fe Flashcards
1
Q
Plane Surveys
A
Type of survey that disregards the curvature of the earth. Appropriate if the area is small.
2
Q
Geodetic Surveys
A
Type of survey that considers the curvature of the earth.
3
Q
Zoned Surveys
A
Type of survey that allows computations to be performed as if on a plane while accommodating larger areas.
4
Q
State Plane Coordinate System
A
Rectangular systems that use a partial latitude/longitude system for baseline references
5
Q
Stadia Survey
A
Requires the use of a transit, theodolite, or engineer’s level, as well as a rod for reading elevation differences and a tape for measuring horizontal distances
6
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Triangulation
A
The positions of the survey points are determined by measuring the angles of triangles defined by the points. Used primarily for geodetic surveys
7
Q
Trilateration
A
Survey lines form triangles, but the lengths of the triangles sides are measured
8
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Photogrammetric Surveys
A
Conducted using aerial photographs
9
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Airborne LIDAR (Light Detection and Ranging)
A
Aircraft mounted laser systems designed to measure the 3D coordinates of a passive target
10
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NAVSTAR GPS
A
Navigation Satellite Timing and Ranging Global Positioning System; one-way satellite to receiver ranging systems. GPS determines position without referencing any other point
11
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Inertial Survey Systems
A
Determine a position on the earth by analyzing the movement of a transport vehicle. Measures acceleration of the vehicle and converts that to distance
12
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Geographic Information System (GIS)
A
A computer system that stores, organizes, analyzes, and displays geographic data. Contains spatial information, literal information, and characteristics
13
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Sexagesimal System
A
Degrees, minutes, seconds. 60 minutes make up a degree, 60 seconds make up a minute
14
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Positions
A
(a) latitude and logitude
(b) by rectangular (Cartesian) coordinates measured from a reference point
15
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Benchmark
A
The common name given to permanent monuments of known vertical positions
16
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Control Stations (or Triangular Stations)
A
Monuments with known horizontal positions.
17
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Datum
A
Usually mean sea level, the point from where vertical elevations are measured from
18
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Tachyometric Distance Measurement
A
“Involved sighting through a small angle at a distant scale
- Stadia method - angle fixed, length measured
- European method - length fixed, angle measured”
19
Q
Stadia Interval/Reading
A
Interval between two rod readings on a distant stadia rod
20
Q
Electronic Distance Measurement (EDM)
A
Very accurate for short (~2 mile) distances and relatively accurate for longer distances
21
Q
Stations
A
In route surveying, lengths are divided into 100’ sections called stations [sta = units]
length: “the length of curve is 4 sta”
location: “the point of intersection is at sta 4””
22
Q
Stakes
A
Usually laid down at full intervals, but if placed anywhere else (plus station):
825’ from 0+00 : 8+25
2896’ from 0+00 : 28+96
23
Q
Leveling
A
The act of using an engineer’s level (or other leveling instrument) and rod to measure a vertical distance (elevation) from an arbitrary level surface.
24
Q
Actual (Corrected) Rod Height
A
ha = Robserved - hrc
hrc = (2.1 x 10^-8 1/ft)*x^2
25
Direct Leveling
A level is set up at a point approximately midway between the two points whose difference in elevation is desired
26
Differential Leveling
The consecutive application of direct leveling to the measurement of large differences in elevation
27
Indirect Leveling
Does not require backsight
28
Meridian
An arc drawn on a map between the North and South poles. (Vertical)
29
Azimuth
Given as a clockwise angle from the reference direction, either from the north or from the south. May not exceed 360 deg.
ex: NAz 320 deg
30
Deflection Angle
The angle between a line and the prolongation of a preceding line is a deflection angle.
Right - clockwise angles
Left - counterclockwise angles
31
Bearing
Referenced to the quadrant in which the line falls and the angle that the line makes with the meridian in that quadrant. May not exceed 90 deg.
ex: N23 deg W "Northwest quadrant, 23 degrees from north meridian"
32
Latitude
The distance that the line extends in a north or south direction (positive toward North, negative toward South)
33
Departure
Distance that the line extends in an East (+) or West (-) direction
34
Traverse
A series of straight lines whose lengths and directions are known.
35
Open Traverse
A traverse that does not come back to its starting point.
36
Closed Traverse
A traverse that comes back to its starting point.
37
Geometric Requirements of Closed Traverse
Sum of deflection angles is 360 deg and sum of the interior angles (of a polygon) with n sides is (n-2)*(180 deg)
38
Traverse Closure
The line that will exactly close the traverse.
39
Bank Measure
A measure of the volume of earth in its natural position. BCY - bank cubic yards
40
Loose Measure
Volume during transport LCY
41
Compacted Measure
Volume after compaction CCY
42
Grade Point
A point where a cut or fill section meets the natural ground
43
Dynamics
The study of moving objects; concerned with bodies that have accelerated motion
44
Kinematics
The study of a body's motion independent of the forces on the body; a study of the geometry of motion
45
Particle
A body in motion where rotation of the body is absent or insignificant; has no rotational kinetic energy
46
Rigid Body
Type of body that does not deform when loaded and can be considered a combination of two or more particles that remain at a fixed, finite distance from each other.
47
Kinetics
A study of the forces that cause the motion
48
Rectilinear Kinematics
Type of kinematics that refers to straight-line motion.
49
Curvilinear Motion
Type of motion that occurs when a particle moves along a curved path.
50
Potential Energy
Stored energy; when energy comes from the position of the particle.
51
Absolute Pressure
Pressures measured with respect to a true zero pressure reference.
52
Gage Pressure
Pressures measured with respect to atmospheric pressure
53
Surface Tension
The tensile force between two points a unit distance apart on the surface, or as the amount of work required to form a new unit of surface area in an apparatus.
54
Stress
Intensity of Force Per Unit Area.
55
Hooke's Law
A simple mathematical statement of the relationship between elastic stress and strain; stress is proportional to strain.
56
What type of stresses are normal strains accompanied by?
Normal stresses
57
Why type of stresses are shear strains accompanied by?
Shear stresses
58
Normal Strain
A change of length per unit of length
59
Shear Strain
An angular deformation resulting from shear stress
60
In fluids, what is pressure a function of?
Vertical Depth and Density
61
Isotropic Material
A type of material that has the same properties in all directions (i.e. steel)
62
Anisotropic Material
A type of material with properties that vary with the direction of loading.
63
Linear Elastic Material
A material where the stress is proportional to the strain within the elastic region; abides by Hooke's Law
64
Brittle Materials
Materials that have very little or no yielding; can fracture suddenly.
65
Ductile Materials
Any material that can be subjected to large strains before it fails (i.e. mild steel).
66
Coplanar at Vector Forces
Two-dimensional; vector forces acting in the same plane.
67
Bank-Measure
The volume of the earth in its natural state.
68
Loose-Measure
The volume during transport.
69
Compacted-Measure
The volume after compaction.
70
Swell
The change in volume of earth from its natural to loose state.
71
Shrinkage
The decrease in volume of earth from its natural state to its compacted state.
72
Common Borrow
Soil found outside the roadway and brought in to the roadway.
73
Cut
Earthwork that is to be excavated.
74
Fill
Excavation that is placed in embankment
75
Cross Sections
Profiles of the earth taken at right angles to the centerline of an engineering project (such as a highway, canal, dam, or railroad).
76
Typical Sections
Show the cross section view of the project as it will look on completion, including all dimensions.
77
Acidity
A measure of acids in solution. In surface water, it is caused by the formation of carbonic acid (H2CO3) from carbon dioxide in the air. Can cause pipe corrosion if not neutralized
pH > 4.5, bicarbonate forms
pH > 8.3, carbonate ions form
78
Alkalinity
A measure of the ability of water to neutralize acids (i.e. , to absorb hydrogen ions without significant pH change). Measure of alkalinity is the sum of each substance measured as equivalent CaCO3.
OH--, CO3--, and HCO3-
79
Hardness
(In natural water) is caused by the presence of polyvalent (but not singly charged) metallic cations.
Mainly Ca++ and Mg++; expressed in terms of mg/L as CaCO3
80
Carbonate Hardness
Caused by cations from the dissolution of calcium or magnesium carbonate and bicarbonate in the water; chemically equivalent to alkalinity. Can be heated to precipitate carbonate and create scale
81
Noncarbonate Hardness
Caused by cations from calcium (i.e. calcium hardness) and magnesium (i.e., magnesium hardness) compounds of sulfate, chloride, or silicate that are dissolved in the water. Cannot be heated to create scale (permanent hardness).
Can be removed by a precipitation softening process (lime soda ash process)/ ion exchange process
82
What type of ions cause hardness?
Multi-positive ions
83
What type of ions cause alkalinity?
Negative ions
84
What type of determinations are made through colorimetric (i.e. wet titration) analysis?
Iron Determinations
85
Fluorosis
Caused by excessive concentration of fluoride; a brownish discoloration of dental enamel.
86
Eutrophication
Over-fertilization of receiving waters.
87
Iron
A contaminant that is a problem in groundwater pumped from anaerobic aquifers in contact with iron compounds. Effects include taste, staining, and sediment.
88
Manganese
A contaminant similar to iron. Effects include taste and staining.
89
Fluoride
A contaminant that is found in groundwaters as a result of dissolution from geologic formations. Effects include dental fluorosis.
90
Phosphorus
A contaminant that is more of a concern in wastewater treatment. Has a major effect on aquatic plant growth and subsequent eutrophication. Bioavailable phosphorous generally does not exceed 60%. Released more in anaerobic conditions when iron and manganese is reduced
91
Nitrogen
A contaminant that can reach large concentrations in groundwaters that have been contaminated with barnyard runoff or that have percolated through heavily fertilized fields. Excessive amounts of this contaminant can contribute to the illness in infants known as methemoglobinemia (blue baby syndrome). Also, stimulates aquatic plant growth.
Total Nitrogen (TN) = nitrates + nitrites + ammonia
92
Turbidity
The resistance of water to the passage of light. A measure of the light-transmitting properties of water and is comprised of suspended and colloidal material. Expressed in NTU, where viruses and bacteria become attached to these particles
93
Total Solids (TS)
The material residue left after the evaporation of the sample. Includes Total Suspended Solids and Total Dissolved Solids.
94
Total Suspended Solids (TSS)
The material retained on a standard glass-fiber filter disk. Can be categorized into volatile suspended solids (vss) and fixed suspended solids (fss).
95
Total Dissolved Solids (TDS)
These solids are in solution and pass through the pores of the standard glass-fiber filter. Can be categorized into volatile dissolved solids (vds) and fixed dissolved solids (fds).
96
Total Volatile Solids (TVS)
The loss in weight during the ignition process (solids capable of digestion)
97
Total Fixed Solids (TFS)
The weight of solids that remain after the ignition used to determine volatile solids.
98
Setteable Solids
The volume measured by allowing a sample to settle for one hour in a graduated conical container.
99
Turbid Waters
Waters with high concentrations of suspended solids
100
Chlorine
The most common disinfectant used in water treatment that deactivates microorganisms.
101
Free Chlorine Residuals
Free chlorine, hypochlorous acid, and hypochlorite ions left in water after treatment
102
Disinfection By-Products (DBPs)
Potential carcinogens! Can take a variety of forms depending on the precursors present, the concentration of free chlorine, the contact time, the pH , and the temperature. The most common ones are the trihalomethanes (THMs), halocetic acids (HAAs), dihaloacetonitriles (DHANs), and various trichlorophenol isomers.
To limit, remove precursors before chlorine treatment
103
Clean Water Act
NPDES permits for discharge to surface waters.
104
Safe Drinking Water Act (SDWA)
Sets maximum contaminant levels (MCLs) and maximum contaminant level goals (MCLGs) for acceptable concentrations of contaminants in public drinking water supplies; sets treatment requirements for pathogens.
105
Clean Air Act (CAA)
Set national ambient air quality standards. Regulates criteria pollutants (CO, ozone, NOx, SOx, PM, lead). Regulates hazardous air pollutants and sets max achiev. control tech
Primary standards - protect public health
Secondary standards - protect public welfare
106
Resource Conservation and Recovery Act (RCRA)
Hazardous waste subtitle c (cradle to grave, defined HazW). Solid waste Title D, Medical waste subtitle J, Underground storage tanks Subtitle I.
107
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
Superfund. Clean up worst historically contaminated sites in the US.
108
National Environmental Policy Act (NEPA)
Requires environmental impact statements (EIS) for federal projects
109
Direct Filtration
Refers to a modern sequence of adding coagulation chemicals, flash mixing, minimal flocculation and subsequent filtration. Applicable when the incoming water is of high initial quality.
110
In-Line Filtration
Refers to another modern sequence that starts with adding coagulation chemicals at the filter inlet pipe. Flocculation and sedimentation facilities are not used
111
MCL
Maximum Contaminate Level, legally enforceable public health goal
112
MCLG
Maximum Contaminant Level Goal; Non-enforceable Limit. Maximum level of a contaminant that is not expected to cause any adverse health effects
113
Apparent Color
Suspended materials or particles that can be removed by centrifugation.
114
True Color
In the form of colloids or vegetative extract - removed by chemical action only.
115
Preliminary Treatment (Pretreatment)
A general term that usually includes all processes prior to the first flocculation operation (includes flow measurement)
116
Screening
Used to protect pumps and mixing equipment from large objects
117
Microstraining
Effective at removing 50-95% of the algae in incoming water.
118
Presedimentation
Purpose is to remove easily settled sand and grit, which can be accomplished by using pure sedimentation basins, sand, and grit chambers, and various passive cyclone degritters.
119
Aeration
In this process, atmospheric oxygen is absorbed by water. Purpose is to reduce taste- and odor-causing compounds, to lower the concentration of dissolved gases, to increase dissolved CO2 or decrease CO2, to reduce iron and manganese, and to increase dissolved oxygen.
120
Clarifiers
Usually rectangular or circular in plan, and are equipped with scrapers or raking arms to periodically remove accumulated sediment.
121
Hydraulic Residence Time (or Detention Time)
The time that water remains in the basin.
122
Sludge
The accumulated sediment. The watery waste that carries off the settled floc and the water softening precipitates.
The mixture of water, organic and inorganic solids, and treatment chemicals that accumulates in settling tanks.
123
Mixers
Coagulants and other water treatment chemicals are added in this.
124
Flocculator-clarifier
Combines mixing, flocculation, and sedimentation into a single tank. (Solid contact units, upflow tanks)
125
Clearwell
Filters discharge into a storage reservoir.
126
Pressure Filters
Operates similarly to rapid sand filters except that incoming water is pressurized up to 25 ft gage. Not used in large installations.
127
Biofilm Filtration (Biofilm Process)
Uses microorganisms to remove selected contaminants. Similar to trickling filters used in wastewater processing.
128
Slow Sand Filters
Operate similarly to rapid sand filters except that the exposed surface (loading) area is much larger and the flow rate is much lower. Alternately exposed to water from a settling tank and to air
129
Ultrafilters
Membranes that act as sieves to retain turbidity, microorganisms, and large organic molecules that are THM precursors, while allowing water, salts, and small molecules to pass through.
130
Adsorption
Occurs when the target contaminant becomes attached to the surface of a medium.
Use Granular Activated Carbon (GAC) or Powdered Activated Carbon (PAC)
131
Precipitation Softening
Using the Lime-Soda ash process adds lime and soda ash to remove calcium and magnesium from hard water.
Soda ash (Na2CO3)
Lime (CaO) forms slaked lime (Ca(OH)2)in an exothermic reaction when added to feed water.
Helps disinfect water but has large quantities of sludge
132
Air Strippers
Device thats primarily used to remove volatile organic compounds (VOCs) or other target substances from water. The compound removed from the liquid phase is transferred to the gas phase
133
Henry's Law
As it applies to water treatment, states that at equilibrium, the vapor pressure of a target substance is directly proportional to the target substance's mole fraction, y.
134
Transfer Unit
A measure of the difficulty of the mass transfer operation and depends on the solubility and concentrations.
135
Height of Packing (Z)
The effective height of the tower.
136
Reverse Osmosis
A type of diffusion in which molecules move under pressure from a solvent to a solution. Membrane demineralization process.
137
Preliminary Treatment
A mechanical process intended to remove floating and larger materials, heavy solids and excessive oils. Odor control, aeration, etc.
138
Primary Treatment
A mechanical (settling) process used to remove oil and most (50%) of the settleable solids.
139
Secondary Treatment
Colloidal and dissolved organics are converted biochemically to settleable biological solids (sludge). Involves biological treatment in trickling filters, rotating contactors, biological beds and activated sludge.
140
Tertiary Treatment (Advanced Wastewater Treatment AWT)
Targeted at specific pollutants or wastewater characteristics that have passed through previous processes in concentrations that are not allowed in discharge, including suspended solids, phosphorous, ammonia, inorganic salts, trace organics
141
Organic Loading Rate
The rate at which organic materials are added to a system. Dependent on the hydraulic loading rate and the amount of organic material in the water source.
142
Solids Loading Rate
The surface loading rate of solids, usually for a sedimentation basin (clarifier).
143
Equalization Tanks
Used to smooth out variations in flow that would otherwise overload wastewater processes.
144
Stabilization Pond
Refers to a pond used to treat organic waste by biological and physical processes. Aquatic plants, weeds, algae, and microorganisms stabilize the organic matter and create oxygen that is used by microorganisms to breakdown organic matter
145
Activated Sludge Process
A secondary biological wastewater treatment process in which a mixture of wastewater and sludge solids is aerated.
146
Secondary Clarifier
Used in activated sludge processes to separate and thicken sludge, enabling recycling of thickened , activated sludge. Essentially sedimentation basins that follow activated sludge processes.
147
MLSS
The bacteria and other suspended material in the mixed liquor; mixed liquor suspended solids.
148
Sludge Volume Index (SVI)
A measure of the sludge's settleability. can be used to determine the tendency toward sludge bulking.
149
Sludge Wasting
The main control of the effluent quality and microorganism population size.
150
Sludge Bulking
Refers to a condition in which the sludge does not settle out
151
Sludge Washout
The loss of solids from the sludge blanket in the settling tank. Can occur during a period of peak flow or even with excess recirculation.
152
Initial Abstraction
The total amount of water that is intercepted (and subsequently evaporates) and absorbed into ground water before runoff begins.
153
Storm Characteristics
The duration, total volume, intensity, and areal distribution of a storm.
154
Volume of Rainfall
The total quantity of precipitation dropping on the watershed.
155
Average Rainfall Intensity
The volume divided by the duration of the storm.
156
Storm Hyetograph
The instantaneous rainfall intensity measured as a function of time.
157
Flood
Occurs when more water arrives than can be carried away.
158
Probable Maximum Flood (PMF)
A hypothetical flood that can be expected to occur as a result of the most severe combination of critical meteorologic and hydrologic conditions possible within a region.
159
Design Flood (or Design Basis Flood, DBF)
The flood that is adopted as the basis for design of a particular project. Usually determined from economic considerations, or it is specified as part of the contract document.
160
Standard Flood (or Standard Project Flood, SPF)
A flood that can be selected from the most severe combinations of meteorological and hydrological conditions reasonably characteristic of the region, excluding extremely rare combinations of events.
161
Interception
A portion of precipitation that is retained on buildings, trees, shrubs, and plants. This is eventually evaporated.
162
Baseflow
The water that percolates deeper into the ground that constitutes the groundwater flow.
163
Detention Storage
A layer of water that is formed as runoff.
164
Transpiration
The water absorbed by plants and crops and eventually discharged into the atmosphere.
165
Water Loss
Precipitation that does not ultimately become available as surface or subsurface runoff.
166
Evapotranspiration
The evaporation of water from soil plus the transpiration of water from plants.
167
Evaporation
The amount of water vaporized into the atmosphere from free water surface and land areas.
168
Unit Hydrograph
Developed by dividing every point on the overland flow hydrograph by the average excess precipitation. Represents 1 in of runoff evenly over the watershed. To use in future settings, multiply unit hydrograph by the total precipitation of the storm
169
Time of Concentration
Defined as the time of travel from the hydraulically most remote (timewise) point in the watershed to the watershed outlet or other design point.
170
Impounding Reservoir (or Retention Watershed or Detention Watershed)
A watershed used to store excess flow from a stream or river.
171
Hydraulics
The study of the practical laws of incompressible fluid flow and resistance in pipes and open channels.
172
Hydraulic Radius
The cross-sectional area in flow divided by the wetted perimeter.
173
Open Channel
A fluid passageway that allows part of the fluid to be exposed to the atmosphere.
174
Reach
A straight section of open channel with uniform shape, depth, slope, and flow quantity.
175
Specific Energy
A term used primarily with open channel flow. It is the total head with respect to the channel bottom. Only kinetic energy and pressure energy contribute (NOT potential)
176
Uniform Flow
Flow with constant width and depth.
177
Impulse-Momentum Principle
States that the impulse applied to a body is equal to the change in that body's momentum.
178
Underground water (or subsurface water)
Contained in saturated geological formations known as aquifers.
179
Aquifers
An underground water reservoir.
Area above GWT is the vadose zone, area below GWT is phreatic zone
180
Free Aquifer (or Unconfined Aquifer)
An aquifer whose water surface is at atmospheric pressure and that can rise or fall with changes in volume.
181
Gravity Well
If a well is drilled into an unconfined aquifer, the water level in the well will correspond to the water table.
182
Storage Capacity (or Storativity or Storage Coefficient)
The change (increase or decrease) in stored aquifer water volume when the aquifer thickness (i.e. piezometric head) changes (increases or decreases).
183
Confined Aquifer
An aquifer that is bounded on all extents.
184
If the confining pressure in a confined aquifer is high enough, the water will be expelled from the surface, and the source is known as an ____________ _______.
Artesian Well
185
Porosity (n)
The volumetric fraction of voids in the soil.
186
Transmissivity (or the coefficient of transmissivity)
An index of the rate of groundwater movement. The product of the aquifer thickness and hydraulic conductivity.
187
Relief Wells
Used to dewater soil.
188
Specific Capacity of a Well
The ratio of short-term sustainable discharge rate to drawdown at the well.
189
Structure
Refers to a system of connected parts used to support a load (i.e. buildings, bridges, towers, pressure vessels, tanks, etc).
190
Dead Loads
Consist of the weights of the various structural members and the weights of any objects that are permanently attached to the structure.
191
Live Loads
Can vary both in their magnitude and location. They may be caused by the weights of objects temporarily placed on a structure, moving vehicles, or natural forces.
192
Concrete
A mixture of cementitious materials, aggregates, water, and air.
193
Workability
Relates to the effort required to transport, place, and finish wet concrete without segregation or bleeding. Closely correlated with slump
194
Durability
Defined as the ability of concrete to resist environmental exposure or service loadings.
195
Modulus of Elasticity (Young's Modulus)
The ratio of stress to strain in the elastic region.Measure of stiffness of an object; defined as the amount of strain resulting from applying a given stress.
196
Structural Steel
Refers to a number of steels that, because of their economy and desirable mechanical properties, are suitable for load-carrying members in structures.
197
Carbon Steels
Use carbon as the chief strengthening element. Divided into four categories based on percentages of carbon.
198
Yield Stress
That unit tensile stress at which the stress-strain curve exhibits a well-defined increase in strain without an increase in stress.
199
Ultimate Tensile Strength
The largest unit stress that the material achieves in a tension test.
200
Ductility
The ability of the material to undergo inelastic deformations without fracture.
201
Toughness
The ability of a specimen to absorb energy and is characterized by the area under a stress-strain curve.
202
Shear Modulus (G)
The ratio of shearing stress to shearing strain during the initial elastic behavior.
203
Service Loads
Designates the loads (forces or moments) that are expected to be actually imposed on a structure during its service life, and for design purposes are taken from building codes.
204
Factored Loads
Designates the service loads increased by various amplifying load factors.
205
Load Factors
Depend both on the uncertainty of the various loads as well as on the load combination being considered.
206
Net Tensile Strain
is the tensile strain at nominal strength exclusive of strains due to effective prestress, creep, shrinkage and temperature.
207
Columns
Vertical members whose primary purpose is to transfer axial compression to lower members
208
Tied Columns
Reinforced concrete columns with transverse reinforcement in the form of closed ties or hoops.
209
Critical Load of Column (or Euler Load)
The load at which a long column fails.
210
Slabs
Structural elements whose lengths and widths are large in comparison to their thicknesses.
211
Flat Plate
Two-way slab supported on a column grid without the use of beams.
212
Flat Slab
A modified version of a flat plate, where the shear capacity around the columns is increased by thickening the slab in those regions.
213
Waffle Slab
A two-way slab often used without beams between column lines.
214
Non-Bearing Walls
A wall supporting their own weight and, occasionally, lateral wind and seismic loads.
215
Shear Walls
A wall designed to resist lateral wind and seismic loads.
216
Ductile Failure
The desirable failure mode. Gives warning and enough time for the occupants of the building to escape prior to collapse.
217
Transverse Loads
Loads that are applied at right angles to the longitudinal axis of the member.
218
Girder
A major beam that often provides support for other beams
219
Floor Beam
A transverse beam in bridge decks.
220
Joist
A light beam that supports a floor.
221
Lintel
A beam spanning an opening (a door or window) usually in masonry construction.
222
Ideal Column
A column that's initially perfectly straight, isotropic, and free of residual stresses.
223
Liquefaction
A sudden drop in shear strength that can occur in soils of saturated cohesionless particles such as sand. When it drops to zero, the sand liquefies (turns to a liquid).
Probable conditions:
1) lightly load sand layer 15-20 m below surface
2) uniform particles of medium size
3) saturated conditions
4) a low N-value
224
Cyclic Stress Ratio
Numerical rating of the potential for liquefaction in sands with depths up to 12m
Th,avg/σ'0
225
Graphical Flow Net
A network of flow paths (outlined by the streamlines) and equal pressure drops (bordered by equipotential lines). Limited to steady, 2D, incompressible, and through a homogenous medium
226
Streamline (Flow Line)
Show the path taken by the seepage (perpendicular to equipotential lines)
227
Equipotential Lines
Contour lines of constant driving (differential) hydraulic head (perpendicular to streamlines)
228
Settling
This is generally due to the consolidation of the supporting soil. The tendency of soils to deform (densify) under applied loads.
229
Confined Compression Tests
Disc of soil confined by a metal ring, covered with porous plates, loaded and submerged in water and measure vertical displacement.
230
Consolidation
A decrease in void fraction.
231
Immediate Settling (Elastic Settling)
Occurs immediately after the structure is constructed. The major settling component in sandy soils.
232
Primary Consolidation
In clayey soil, this type of consolidation occurs gradually due to the extrusion of water from the void spaces.
233
Secondary Consolidation
This type of consolidation occurs in clayey soils at a much slower rate after the primary consolidation has finished.
234
Normally Consolidated Clay
Virgin clay that has never experienced vertical stress higher than its current condition.
235
Overconsolidated Clay
Clay that has previously experienced a stress that is no longer present.
236
Rebound Curve/Reloading Curve
The result on NC clay unloading and reloading. Considered to be OC in this region, because it had experienced higher stress in the past.
237
Compression Index (Cc)
The logarithmic slope of the virgin compression curve (below)
238
Recompression Index (Cr)
The logarithmic slope of the recompression segment (above)
239
Preconsolidation Pressure
The maximum pressure that the soil saw prior to the new (structure) loading.
240
Direct Shear Test
Used to determine the relationship of shear strength to consolidation stress. A disc of soil is inserted into a direct shear box where the top and bottom halves can move laterally; normal stress is applied vertically and a measure of horizontal/vertical displacement and shear load are taken
**forced failure plane along horizontal!
241
Unconfined Compression Test
A cylinder of cohesive soil is loaded axially to compressive failure (clays usually).
242
UU Test
Unconsolidated Undrained test; Angle of internal friction is zero because water is incompressible and and cannot escape the sample, and the effective stress does not change, hence the internal angle of friction is zero.
Undrained shear strength (Su) is equal to the cohesion (c) in this case. Undrained shear strength is half of the unconfined compressive strength (qu)
243
Shallow Foundation
Refers to a foundation system in which the depth of the foundation is shallow relative to its width. includes spread footings, continuous (wall) footings, and mats.
244
Bearing Capacity
The ability of soil to support foundation loads without shear failure
245
General Shear Failure
Soils resists an increased load until a sudden failure occurs
246
Local Shear Failure
Occurs in looser, more compressible soils and at high bearing pressures
247
Sand vs. Clay
Foundations - sand is good - strong and drains quickly
Excavations - clay is good (good cohesion) - usually lower strength than sand
248
Footing
An enlargement at the base of a load-supporting column that is designed to transmit forces to the soil
249
Spread Footing
A footing used to support a single column
250
Continuous footing
A long footing supporting a continuous wall
251
Combined Footing
A footing carrying more than one column
252
Cantilever Footing
A combined footing that supports a column and an exterior wall or column
253
Differential Settlement
Unequal settlement of the various parts of a building, which may cause excessive stresses in the structural frame or tilting of the building.
254
Allowable Bearing Capacity (qa)
The net pressure in excess of the overburden stress that will not cause shear failure or excessive settlements. The soil pressure used to design the foundation.
qa = qnet/FS
255
Which term dominates the bearing capacity in cohesive soil?
Cohesion term
FS = 3
256
Which term dominates the bearing capacity in cohesionless soil?
The depth term
FS = 2
257
Gravity Wall
A high-bulk structure that relies on self-weight and the weight of the earth over the heel to resist overturning
258
Semi-Gravity Walls
Similar but not as large
259
Buttress Wall
Depends on compression ribs between the stem and the toe to resist flexure and overturning
260
Counterfort Walls
Depends on tension ribs between the stem and the heel to resist flexure and overturning
261
Cantilever Wall
Resists overturning through a combination of the soil weight over the heel and the resisting pressure under the base. Consists of a base, a stem, and an optional key
262
Cohesive Soil
Clay-like, angle of internal friction close to zero
263
Granular Soil
Sand/gravel-like, cohesion close to zero
264
Earth Pressure
The force per unit area exerted by a soil on the retaining wall
265
Active Earth Pressure
Present behind a retaining wall that moves away from and tensions the remaining soil
266
Passive Earth Pressure
Present in the front of a retaining wall that moves toward and compresses the soil
267
σ' for above and below water table
σ' = γ1H1 +H2(γ2 - γw)
where H1 is above the GWT and H2 is below
268
Surcharge
Any additional loading applied externally to the soil
269
Rankine Earth Pressure Theory
Assumes that failure occurs along a flat plane behind the wall inclined at an angle alpha from horizontal
270
Shearing Resistance
The maximum shearing force that a wedge can support
271
Excavation
Any place where soil has been removed from its original location
272
Braced Cut
An excavation in which the active earth pressure from one bulkhead is used to support the facing bulkhead
273
Mudline
Bottom of an excavation (base of the cut)
274
Sheet Piles
Rolled steel sections that are driven into the ground to provide lateral support; act as a continuous wall.
Bending stress is usually 65% of yield stress
275
Cantilever Wall/Bulkhead
Untied flexible bulkhead
276
Anchored Bulkhead
Tied bulkhead. Failure through base layer heave, anchorage failure, toe kick-out (toe embedment at base fails), sheeting failure
277
Spoils
The soil removed from an excavation; must be placed far enough away to not cause surcharge lateral loading
278
Transportation Planning
Involves travel demand analysis and forecasting and utilizes mathematical models to predict the volume of trips between activity centers
279
Travel Time and Delay Study
A study that assesses the time it takes a vehicle to travel between two points along a given route (referred to as the study segment). Usually to and from a Central Business District (CBD)
280
Traffic Volume Studies
Studies used to determine the numbers, movements, and classifications of vehicles (and/or bicycles and pedestrians) at specific locations and times.
281
Trip Generation
A model that requires estimating the number of trips that will result from a particular population or occupancy. Forecasts the number of trips that will be made.
282
Trip Distribution
A model that estimates the number of trips between study regions (zones). Determines where the trips will go.
283
Gravity Model
1) trips generated from one zone will be proportional to the trips ending in another zone
2) the number of trips between two zones is inversely proportional to the distance between them
284
Logit Model
Determine the utility of a mode of transportation (satisfaction of using a mode of transportation, Ux). Can show the probability of choosing certain modes (ex: auto over transit)
285
Freeway
A divided corridor with at least two lanes in each direction that operates in an uninterrupted flow mode (i.e., without fixed elements such as signals, stop signs, and at-grade intersections).
286
Highway
2+ lanes. Contain some fixed elements and access points from at-grade intersections, though relatively uninterrupted flow can occur if greater than 2 miles apart
287
Capacity Planning Analysis
Used to estimate the traffic carrying ability of transportation network segments at prescribed levels of operation
288
Free Flow Speed (FFS)
The theoretical speed (mi/hr) of traffic flow in a given freeway segment during low-volume conditions when traffic density is zero
289
Demand Flow Rate
Expressed in passenger cars per hour per lane (pc/hr/ln)
290
Heavy Vehicle Factor
A way to relate trucks and buses to passenger cars
291
Vehicle Density
The quantity of vehicles within a given freeway segment at a given time (pc/hr/ln)
292
Design Speed
The maximum safe speed that can be maintained over a specified section of roadway when conditions are so favorable that the design features of the roadway govern.
293
Legal Speed
Speed that is often set at approximately the 85th percentile speed. Determined by observation of a sizable sample of vehicles.
294
Volume-Density-Speed
q = kv
```
q = volume
k = density
v = speed
```
295
Peak Hour Factor (PHF)
measure of the fluctuation in traffic flow during the period of analysis. [V/(4*V_15)]
296
Greenshield's Model
linear relationship between speed and density. When density approaches zero, speed approaches zero
297
Signal Phases
- two phase - one phase for each axis of travel
- three phase - provides one road with left turn signal
- four phase - provides both roads with left turn signals
298
Control Delay
Consists of only the portion of delay attributable to the control facility
299
Geometric Delay
caused by the need for cars to slow down in order to negotiate the intersection
300
Queueing Delay
caused by the need to slow down to avoid other vehicles already present
301
Incident Delay
occurs when there is an incident (accident)
302
Yellow Interval
The length of time a design driver, once the signal turns yellow, needs to stop a vehicle before entering the intersection.
303
Red Clearance Interval
The length of time a design-driver needs to completely clear the intersection.
304
Queue
A waiting line.
305
Horizontal Circular Curve
A circular arc between two straight lines known as tangents.
306
Intersection Angle (I)
Has units of degrees unless otherwise noted
307
Deflection Angle of Subchord
If a deflection is given, then it is equal to d/2 (d is the angle of subchord)
308
Superelevation
The difference between the inner and outer elevation of a track or roadway, is also transitioned along the easement, providing a smooth and comfortable ride for passengers by changing the cross slope in proportion to the change in curve radius.
309
Vertical Curve
Used to connect two vertical tangents in order to change the grade of a highway.
310
Sight Distance
The length of roadway a driver can see ahead of the vehicle.
311
Stopping Sight Distance (SSD)
The total distance required for a driver traveling at design speed to stop a vehicle before reaching an object in its path.
312
Decision Sight Distance (DSD)
The distance appropriate where hazards exist that require drivers to make decisions to perform maneuvers other than a stop, such as lane changes or exit ramp selections, in order for traffic to proceed in an orderly and smooth fashion.
313
Passing Sight Distance
The distance applicable on two-lane highways when there are sufficient gaps in opposing flows to allow passing maneuvers to occur and when there are few access points.
314
Water Cement Ratio
The amount of free water available for hydration. Used to determine the strength qualities, workability, and dissolvability of a mix.
315
Fatigue Resistance
Refers to the ability to withstand repeated wheel loads.
316
Skid Resistance
Refers to the ability to resist tire slipping or skidding.
317
ESALs
The number of 18,000 lbf single axles (with dual tires) on pavements specified strength that would produce the same amount of traffic damage over the design life of the pavement.
ESALs = (no. of axles)*(LEF)
318
Igneous Rock
A rock formed from melted rock that has cooled and solidified.
319
Sedimentary Rock
A rocked formed at the surface of the Earth. They are layered accumulations of sediments - fragments of rocks, minerals, or animal or plant material.
320
Metamorphic Rock
A rock that forms when sedimentary and igneous rocks buried in the Earth's crust are subjected to pressures so intense or heat so hight that the rocks are completely changed.
321
Rock Quality Designation (RQD)
A rough measure of the degree of fracturing (jointing) in a rock mass, measured as a percentage of drill core lengths that are unfragmented; considered soil-like when RQD<50%
322
Soil
An aggregate of loose mineral and organic particles. Primarily composed of gravel, sand, silt, and clay.
323
Stokes' Law
Relates the speed of a particle falling out of suspension to its diameter and solid density. What hydrometer analysis is based on.
324
Cu (Hazen Uniformity Coefficient)
Indicates the general shape of the particle size distribution.
D10 = effective grain size - diameter for which 10% of particles have a smaller diameter
325
Well Graded Soils
Soils that have uniformity coefficients greater than 10 and have a continuous, wide range of particle sizes.
326
Uniformly Graded
Cu is less than 4 or 5; all particles fall within a narrow range
327
Gap Graded Soils
Soils that are missing one or more ranges of particle sizes.
328
Coefficient of Curvature (Cc)
measure of curvature of grain size distribution plot;
Cc = D302/D10D60
329
Atterberg Limits Test
The plasticity characteristics of the fines fraction of a soil are measured in the laboratory using this test. Clay changes behavior based on its water content!
330
Liquid Limit
The water content at which the soil rejoins at exactly 25 blows. The water content corresponding to the transition between the plastic and liquid state.
331
Plastic Limit
The water content corresponding to the transition between the semi-solid and plastic state. Rolling a sample into a 1/8" thread until it crumbles. Sand and silts don't have a plastic limit in general!
332
Plasticity Index
The difference between the liquid and plastic limits. Indicates the range in moisture content over which the soil is in a plastic condition.
PI = LL - PL
333
AASHTO Classification System
Based on sieve analysis, LL, and PI.
334
Group Index (GI)
A means of comparing soils within a group, not between groups.
GI = 0; good subgrade material
GI > 20; poor subgrade material
F = percentage of soil passing No 200 sieve
335
United Soil Classification System (USCS)
Based on grain size distribution, LL, and PI.
336
Relative Density (Dr)
A measure of the densification achieved in a granular soil. A fraction representing how much a granular soil is compacted relative to the total possible compaction determined in the lab
337
Effective Stress (σ')
Portion of the total stress that is supported through grain contact. Average stress on a plane through the soil
σ' = σ - u
338
Pore Water Pressure (u)
The hydrostatic pressure below the water table, and it is calculated in the same manner as hydrostatic pressure; the effect of buoyancy
339
Total Stress (σ)
The actual contact stress between two soil particles
340
Permeability
A measure of contiguous voids (supports the flow of water)
341
Constant Head Test
The volume of water over time is measured while keeping the hydraulic gradient constant. For coarse-grained soils.
342
Falling Head Test
Head will change from h1 to h2 and used to find the permeability. For fine-grained soils.
343
Hydraulic Head (i)
The hydraulic head per unit length of the sample soil
344
Project Management
The coordination of the entire process of completing a job, from its inception to final move-in and post-occupancy follow up
345
Partnership
Various stakeholders of a project are brought into the decision-making process.
Pros: shared responsibility, closer communication
Cons: day-to-day management is hard
346
(PMBOK) Project Management Body of Knowledge
Defines the fundamentals of project management; is process based, meaning it describes projects as being the outcome of multiple processes
347
5 PMBOK process groups
1. Initiating
2. Planning
3. Executing
4. Monitoring and Controlling
5. Closing
348
PMBOK 9 Knowledge Areas
1. Integration
2. Scope
3. Time
4. Cost
5. Quality
6. Human Resources
7. Communications
8. Risk
9. Procurement
349
Cost Estimating
Begins with decision to submit a project bid, determine the quantity of materials and labor (takeoff), prepare a cost summary, prepare the bid proposal for submission to owner
350
Scheduling
Includes design sequencing (A) and construction sequencing (GC)
351
Design Sequencing
- SD Phase: general layout and alternative building systems
- DD Phase: Refines and further develops decisions made
- CD Phase: final working drawings/contract documents
- Bidding/Negotiation Phase: bids given, a contractor is selected
- Construction Phase
352
Factors that affect scheduling
Size/complexity of project, number of people working on the project, abilities and design methodology of project team, type of client
353
Construction Sequencing
Creating and following a work schedule that balances the timing and sequencing of land disturbance activities and the installation of erosion and sedimentation control (ESC) measures
354
Time-cost Tradeoff
the cost increases as the project time is decreased and vice versa
355
Direct Costs
vary directly with level of output (labor, materials, etc)
356
Indirect Costs
not directly related to a particular function or product (taxes, admin)
357
Crash time
the shortest possible time to complete an activity
358
Fast Tracking
A schedule compression technique in which activities or phases (design and construction) normally done in sequence are performed in parallel for at least a portion of their duration.
359
Resource Leveling
Used to address overallocation situations. A technique in which start and finish dates are adjusted based on resource constraints with the goal of balancing demand for resources with the available supply/ tasks can be split
360
Critical Path Method (CPM)
a project-management tool that illustrates the relationships among all the activities involved in completing a project and identifies the sequence of activities likely to take the longest to complete
361
Monitoring
Keeping track of the progress of the job to see if the planned aspects of time, fee, and quality are being accomplished
362
The __________________ effectively monitors project progress by integrating both time and cost into a single performance measurement
Earned Value Method
363
Work Breakdown Structure (WBS)
A hierarchical decomposition of the total scope of work to be carried out by the project team to accomplish the project objectives and create the required deliverables.
364
BCWS (Budgeted Cost of Work Scheduled)
Value of all work scheduled to be accomplished in a given period of time
365
ACWP (Actual Cost of Work Performed)
the cost incurred and recorded for performance measurement purposes within a given time period and is simply the actual cost.
366
BCWP (Budgeted Cost of Work Performed)
Also referred to as Earned Value. The value of all work actually accomplished in a given period of time and represents the completion of work.
367
Cost Variance (CV)
CV = BCWP - ACWP
368
Schedule Variance (SV)
SV = BCWP - BCWS
369
Cost Performance Index (CPI)
A measure of the cost efficiency of budgeted resources expressed as the ratio of earned value to actual cost. Greater than 1 is efficient
370
Schedule Performance Index (SPI)
A measure of schedule efficiency expressed as the ratio of earned value to planned value. Greater than 1 is ahead of schedule
371
Budget at Completion (BAC)
The sum of all budgets established for the work to be performed.
372
Estimate to Complete (ETC)
The expected cost to finish all the remaining project work.
373
Estimate at Completion (EAC)
An estimate of what it will cost to complete the project based on performance to date
374
Procurement
When a project manager plans purchases, acquisitions, and contracts, selects suppliers and contractors, etc
375
Design-Bid-Build
A project delivery method in which the owner holds two separate contracts for design and construction. This method is often referred to as the traditional project delivery method.
Pros: lowest cost
Cons: takes longer than other methods
376
Multiple Prime
A contracting methodology in which the owner bypasses the use of a general contractor and enters into multiple separate contracts with trade or specialty contractors for the various sections of the work associated with the project, such as concrete, framing, mechanical, and electrical work. Each of the specialty contractors involved becomes a prime contractor on the project.
Pros: can reduce duration and cost
Cons: complicated!
377
Design-Build
The owner contracts with one entity (a person or firm) to provide both design and construction services, that entity then subcontracts portions of the work to others as needed
Pros: can offer the owner a fixed, guaranteed price and assume all responsibility for design and construction
378
Construction Manager
Third party who is an expert in the construction, costing, and management of the construction process. Can act as an agent to owner, a contractor, or a consultant
379
Management Contracting
Act as an agent to the owner, advising the engineer on material selection, costs, and constructibility, selecting subcontractors, negotiating contracts, etc.
380
Negotiation
The owner, with help of CM or E, works out the final contract price and conditions with each contractor
381
Competitive Bidding
The bid is usually awarded to the lowest responsible bidder. Can't prohibit because it violates the Sherman Antitrust Act (unreasonable restraint of trade)
382
Documentation
Everything done on a project must be documented in writing
383
Change Order
A written order signed by the contracting officer, directing the contractor to make changes that the changes clause of the contract authorizes the contracting officer to order without the consent of the contractor. Due to unexpected conditions or plans after bidding
384
As-Built Construction Documents
Record what was actually installed as opposed to what was shown in the original plans. MUST be certified by the engineer in the project (stamp/seal)
385
Construction Plans
Shows building configuration from top down. Scales include 1/8"=1' (1:100), 1/4"=1' (1:50), and 1/2"=1' (1:25). Should have a consistent scales across plans in the same set of drawings
386
Specifications (Specs)
Dictate which materials and methods must be used for a given construction project. Specific and technical
387
CSI MasterFormat
A systematic listing of construction trades, materials, systems, and administrative requirements published by the Construction Specifications Institute (CSI) for the purpose of organizing construction specifications. Current has 50 divisions
388
Equipment
The most important considerations include its ability to perform work, its cost, and its efficiency. Capability is based on how quickly the work is completed. Cycle time is how long it takes the equipment to finish and begin next action.
389
Cost Per Unit of Production (CPP)
The amount of time it takes to complete the work relative to the cost of renting, operating, and maintaining the equipment for that period of time
390
Dozer
Equation for calculating blade capacity in LCY has a dimensionless factor 0.375
V = 0.375hwl
391
Compaction Equipment
Granular soils (gravel/sand) - smooth wheel roller, vibratory plate, tamper
Loamy soil - rubber tired roller
Highly cohesive soil - Sheep's foot roller
392
Cranes
Evaluation includes determining the type and size of crane needed, the load capacity, and other specs required for the project
393
Mobile Crane
Typically powered by a diesel engine and comprises a base frame, outriggers (increase operating range), a superstructure, a boom, and a hoisting tackle
394
Tower Crane
Comprise a vertical standing lattice-frame central mast. Boom can be set high enough off the ground to clear any obstructions. Good for low-rise construction
395
Tipping Load
The weight at which the crane will tip or otherwise become unsafe. Load capacity is never more than 75% of tipping load
396
Critical Path
in a PERT network, the sequence of tasks that takes the longest time to complete. This is the shortest possible time in which a project can be completed successfully.
397
Productive Work
Work that contributes directly to the completion of that activity
398
Contributory Work
Is not directly contributing but is essential for completion/increases efficiency of direct work
399
Nonproductive Work
Does not contribute to completion/reworked stuff
400
Obstructive Work
Prevents activity from being completed
401
Labor Utilization Factor
An engineer takes random observations of various project crews or pieces of equipment and observes how much work and what type of work each performs on an activity. Usually around 25-50%
402
Learning Curve
"As a contractor works on more projects and gains more experience, they will improve at the job and have a higher rate of productivity. Graph that shows the time spent to produce a unit of work.
Integration under this curve is the total hours needed to complete an activity (used to estimate cost of labor)"
403
Dewatering
removal of water from an excavation before and during excavation
404
Wells
Holes dug or drilled deep into the ground to reach a reservoir of groundwater. Used to lower water table using submersible pumps
405
Vacuum Dewatering
Uses wellpoints to draw water up small diameter tubes with side perforations in the liquid water zone
406
OSHA (Occupational Safety and Health Administration)
Regulates safety of workers in the US
1910 standards - general industry
1926 standards - construction industry
407
Type A Soil
Cohesive soil with an unconfined compression strength of 1.5 tons per square foot or greater. Can't have fissures or be disturbed or not type A
53 degrees max slope
408
Type B Soil
Cohesive soils with an unconfined compression strength between 0.5 and 1.5 tsf, granular cohesionless soils, unstable dry rock, type A soils that are exposed to a strength reduction factor
45 degrees max slope
409
Type C Soil
Cohesive materials with an unconfined compressive strength of 0.5 tsf or less.
34 degrees max slope
410
Layered Geological Strata
classified based on its weakest layer of soil
411
Trenching and Excavation OSHA
Except for excavations on entirely stable rock, anything deeper than 5' must have shoring, trench shields, sloping/benching to protect from cave-ins.
Greater than 20', must be designed by a PE
412
Competent Person
Someone with training, experience, and knowledge, capable of identifying existing and predictable hazards in the surroundings or working conditions that are unsanitary, hazardous, or dangerous to employees, and who has the authority to take prompt corrective measures to eliminate them
413
Trained Person
Has been trained in specific tasks
414
Fall and Impact Protection
Hav fall protection devices, train employees in the equipment being used, have protection from exposed rebar (impalement), helmets and PPE
415
OSHA Noise Exposure Limits
90 dBA 8 hr/day
416
Scaffold
a temporary platform used in work on a building
417
Temporary Structures
High factors of safety required
418
Reeving
The path of the wire rope as it comes off the hoist drum
419
Eccentric Reeving
When hoist line is not centered over the boom tip, the boom twists
420
Qualified Person
A person who, by possession of a recognized degree, certificate, or professional standing, or by extensive knowledge, training, and experience, has demonstrated the ability to solve or prevent problems relating to a certain subject, work, or project.
421
Creed
a statement or oath taken or assented to by an individual in ceremonies
422
Engineer Creed
advancement and betterment of human welfare
423
rule
guide for conduct and acting in certain situation, or a regulation governing procedure
424
statutory rule (statute)
enforced by legislative branch and carries the weight of the law
425
cannon
individual principle or body of principles, rules, standards, or norms
426
Code
a system of principles or rules
427
ASCE
American Society of Civil Engineering
428
ASCE cannons
- focus on safety, health, and welfare / sustainable development
- only in area of their competence
- shall issue public statements only in a truthful manner
- act in professional matter to avoid conflicts
- no unfairly competition/ professional reputation on the merit of their service
- be honorable and have integrity, zero tolerance for bribery, fraud, and corruption
- Continue professional development throughout career
429
Ethics
rules of conducts
430
We need engineer conducts because
it is easy for engineers to take advantage of clients. Engineers must represent the interests of their employers or clients and protect public health, safety, and welfare
431
Sustainability
Any design or development that seeks to minimize negative impacts on the environment so that the present generation's resource needs do not compromise the resource needs of future generations
432
Engineering
Profession rather than an occupation because of special privileges, special knowledge, and special responsibilities; regulated by ethical standards
433
Model Rule (NCEES Rule of Professional Conduct)
- Licensee's obligation to society
- licensee's obligation to employers and clients
- licensee's obligation to other licensees
434
Conceptual Issues
Definitions of terms may be in dispute
435
Most responsibility
-The public welfare
436
Licensee's Obligation to society
- first and foremost responsibility is to the public welfare
- only approve and seal designs that meet standards and safeguard public
- notify client/employer of danger
- truthful report/comprehensive report
- adequate knowledge/ a competent evaluation of subject matter when expressing opinion publically
- no criticism and favoritism on technical matters which are paid for by interested parties
- no using name or company name or associate with fraudulent practices
- rule will be strictly follow and engineer will provide board with info necessary to make a determination on this violation
437
Licensee Obligation to employer and clients
- legitimate education in the field of work
- don't affix their signatures or seals to work outside of their area of competency/outside of their supervision
- Can accept assignments that have components outside of expertise but must get those sections sealed by appropriate people
- no release info without consent/no gratuities from contractors, agents, etc.
- conflict of interest needs to be disclosed
- no earning money from different parties during the same project unless agreed upon
- don't solicit or accept a professional contract from a government body on which a principal or office of their organization is a member
438
Plan stamping
only legal for signing off on a project you design and/ or check
439
Licensee to other Licensee
- no misrepresentation of their, or their associates, professional qualification
- shall not offer, give, solicit, or receive, either directly or indirectly, any commission or gift in order to secure work; shall not make any political contribution with the intent to influence the award of a contract by public authority
- shall not attempt to injure another's reputation, prospects, practice, or employment
440
Ethical Priorities
1. society and the public
2. the law
3. the engineering profession
4. the engineer's client
5. the firm
6. other involved engineers
7. self
441
Dealing with Clients and Employees
Don't accept assignments outside of competency area, protect interest of clients, keep confidential information confidential, avoid conflicts of interest, no compensation from more than one party, explain consequences of rejected recommendation, openly admit errors made
442
Dealing with Suppliers
Don't accept gifts or other valuable considerations, enforce plans but also interpret the contract documents fairly, have complete plans and specs, don't delay performance of suppliers. Suppliers don't have to spend the time or money to furnish materials not called for in the plans or contract documents
443
Dealing with Suppliers, an engineer may
spend personal time outside of contract to ensure adequate performance
444
Dealing with Other Engineers
Should not injure others' reputation, review someone else's work while the other engineer is still employed, replace another engineer, moonlight (compete unfairly using salaried position). An engineer should freely report, publish, and distribute information that would be useful to other engineers
445
Dealing with the Public
Place service and humankind above personal gain, consider the welfare of public, indicate if public statements are on anyone's behalf, develop appreciation of the engineering profession, whistleblow when needed
446
"Whistle-blowing"
"Whistle-blowing" is calling public attention to illegal actions taken in the past or taken currently by your employer. It jeopardizes your own good standing with your employer.
447
Competitive Bidding
Engineers and firms may refuse to bid competitively, clients are not required to seek competitive bids, any prohibition of competitive bid on the state level remain unaffected, can lobby for legislation to prohibit competitive bid
448
The US department of justice successful action in 1970 against engineering code of ethics that formally prohibited competitive bidding was based on premise that
the prohibition violated antitrust statutes
449
Boilerplate clauses
Clauses have specific wording that don't normally changed ex. delays policy, performance policy,
450
Retainer
A minumum amount paid by the client, usually in total and in advance, for a normal amount of work expected during an agreed-upon period
451
Tort
civil wrong committed by one person causing damage to another person or person's property, emotional well-being, or reputation
452
Liens
The lien establishes the supplier's security interest in the property. The property owner is prevented from transferring the title of the property until the lien has been removed from the supplier
Right to hold the property due to various reason such as no payments
453
Engineering is a profession because we have
special knowledge, special privileges, and special responsibilities.
454
plan stamping
the illegal action of signing off on a project didn't design and check
455
The US departmet of justice sucessful action in 1970 against engineering code of ethics and formally prohibited competitive bidding was
based on the premise that the prohibitions violated antitrust statues
456
Contract
a legally binding agreement or promise to exchange goods or services; can be written or verbal
457
Requirements of a Contract (to be binding)
1) There must be a clear, specific, and definite offer with no room for ambiguity or misunderstanding
2) There must be some form of conditional future consideration (i.e. payment)
3) There must be an acceptance of the offer
implicit conditions: must be voluntary for all parties, all parties must have legal capacity, the purpose of the agreement must be legal
458
A contract should include...
- introduction, preamble, or preface indicating the purpose of contract
- name, address, and business forms of both contracting parties
- signature date
- effective date of agreement
- duties and obligations of both parties
- deadlines and requires services
- fee amount / schedule / payment terms
- agreement expiration date
- standard boilerplate clauses
- signatures of parties
- declaration of authority of the signatories to bind the contracting parties
- supporting documents
459
Agent
Acts on behalf of the principal (fiduciary relationship - act in the best interest, honest, loyal). The decision-making authority and right of action are transferred from the owner (principal) who would normally have that authority to the agent (e.g., engineer as the agent).
460
Standard Boilerplate Clauses
- force majeure
- contract doc is the complete agreement
- the contract can be canceled or modified only in writing
- severability - parts of the contract that are voided do not mean the rest of the contract is voided
- assignment of rights or responsibilities
- all notices sent to address in contract
- time is of the essence
- subject headings do not control paragraph content
- laws of state signed in controls interpretation of contract
- disagreements arbitrated by AAA
- lawsuits must be filed in state of contract signature
- specific performance
- prevailing parties are entitled to attorney and court fees in a lawsuit
- consequential damages are not recoverable in a lawsuit
461
Subcontract
When a party to a contract engages a third party to perform work in the original contract, the contract with the third party is a subcontract; whether this can occur is dependent on the assignment clause of the contract
462
Owner
the person, partnership, or corporation that actually owns the land, assumes the financial risk, and ends up with the completed project
463
Developer
Person who contracts with the architect and/or engineer for the design and with the contractors for the construction of a project
Owner-developer - owner is also developer
464
Architect
designs the project according to established codes and guidelines
465
Engineer
Conducts stress and capacity calculations
466
Contractors (Prime, General, Sub)
Who the contractor hires to complete construction
General contractor - acquires entire project, separates into subcontracts
Prime - the GC that hires the subcontractors - liable for damage suffered by owner-developer from acts of subcontractors
467
Construction Manager
The person who manages construction (agent)
468
Standard contracts for design professionals
Major advantage because the meanings of the clauses are well established
469
Lump sum fee
A predetermined fee decided upon by the client and the engineer. Use if a small prject and the scope is clearly defined
470
Unit Price
Contract fees are based on estimated quanitites and unit pricing. Use when material quanitites can be accurately determined and estimated before the contract is finalized
471
Cost Plus Fixed Fee
All costs incurred by the engineer are paid by the client. Use when the scope of services cannot be determined accurately in advance
472
Per Diem Fee
The engineer is paid a specific sum for each day spent on the job
473
Salary Plus
The client pays for the employees on an engineer's payroll (the salary) plus an additional percentage to cover indirect overhead and profit plus certain direct expenses.
474
Incentive
Based on established target costs and fees; lists minimum and maximum fees and an adjustment formula (payment calculated based on this formula)
475
Percentage of Construction Cost
Pays A/E a percentage of the final total cost of a project
476
Contract discharge
- all parties have satisifed their obligations
- mutual agreement of all parties to terminate
- impossibility of performance
- illegality of the contract
- material breach
- fraud
- failure of consideration
** Extreme difficulty in satisfying the contract does not discharge it
477
Contract Breach
Failure to perform a contractual obligation. Can be willful or unintentional
478
Material Breach
A breach that occurs when a party renders inferior performance of his or her contractual duties.
479
Specific Performance
An equitable remedy in which the court orders the contract to be performed as agreed to by the parties. Punitive damage is usually unavailable
480
Negligence
An action, willful or unwillful, taken without proper care or consideration for safety, resulting in damages to property or injury to persons. Must prove duty, breach, causation, and harm to win
481
Proper Care
The diligence that would be exercised by a reasonably prudent person
482
Comparative Negligence
A theory in tort law under which the liability for injuries resulting from negligent acts is shared by all parties who were negligent (including the injured party), on the basis of each person's proportionate negligence.
483
Fraudulent Misrepresentation
Any misrepresentation, either by misstatement or by omission of a material fact, knowingly made with the intention of deceiving another and on which a reasonable person would and does rely to his or her detriment. Can receive punitive damages for this
484
Tort Action
A civil lawsuit is brought by the alleged injured party (plaintiff) against the defendant. Must have been injury (damage). Usually concerned with compensation for an injury
485
Strict Liability
The injured party wins if the injury can be proven (most common in product defect cases - forseeable damage). Do NOT need evidence of willful/unwillful negligence or intent
486
Standard of Care
Design professionals are expected to maintain a standard of care and have comparable skills to their peers
In the absence of a contract, design professionals are not held to be guarantors of their work in a strict legal liability - could have tort action, not really breach
487
Consumer Product Manufacturer Rules
Manufacturers are held liable for all phases of design, held to strict liability in tort without regard to negligence
Designer is usually not punished, but company is
488
Caveat Emptor
"Let the buyer beware"
489
Damages
The award made by the court for losses incurred by the injured party
- General - make up for injury
- Special - awarded for direct financial loss due to the breach of a contract
- Nominal - responsibility est. but injury is inconsequential
- Liquidated - amounts specified in the contract for nonperformance
- Punitive - in tort/fraud cases to punish and make an example of the defendant
- Consequential - provide compensation for indirect losses incurred by the injured party but not directly related to the contract
490
Errors and Omissions Insurance
Insurance which financially protects an architect against claims for damages resulting from professional negligence. Also called professional liability insurance.
491
Engineering Licensing
An examination process by which a state's board of engineering licensing determines and certifies that an engineer has achieved a minimum level of competence
492
US Licensing Procedure
FE/EIT exam, then the PE/P&P (Principles and Practices Examination)
493
Uniform Examinations
Each state adopted the NCEES exam score cutoffs and exam itself
494
Reciprocity
The issuance of an engineering license based on another state's licensing
495
Stationing on a Horizontal Curve
The PT station is equal to the PC station plus the length of the curve (because it is the actual distance the vehicle would drive on)
496
Sag Vertical Curve
Concave upwards \/ (- to +)
497
Crest Vertical Curve
Concave downwards /\ (+ to -)
498
Turning Point
High point - crest curves
Low point - sag curves
The location where the slope is zero
499
Perception Reaction Time (PIEV)
Measured from the moment a driver sees an object to the time the brakes are applied. AASHTO 2.5 SECONDS
500
Pavement Design
Involves matching a project's strength and durability requirements to a given material
501
Horizontal loads
Those from braking, accelerating, turning, etc. included in asphalt but not concrete
502
Pavement loadings (stationary)
Wheel load repetitions not accounted for but max load applied for concrete and distribution of load for asphalt is considered
503
Highway Pavement Thickness
Heavily traveled - 300 mm
| Frost area - 152 mm +
504
Soils and Subgrade
Best to have good load strengths, drain well, not affected by frost or heaving, free of organic materials, and can be shaped and compacted into a stable mass
A-1 or A-2; have less than 35% fines
505
Concrete Pavement
High strength, durable, resistant to abrasion, chemical attack, and spilled fuel solvents, higher cost
506
Asphalt Pavement
Can be rapidly placed, requires less skill, can be installed on weaker subgrade sections, environmental concerns. Elastically rebounds (flexible pavement); visco-elastic
507
Hot Mix Asphalt (HMA)
A mixture of asphalt cement and well-graded, high quality aggregate that is heated and compacted into a uniform, dense mass.
Easily repaired
508
Deep Strength Asphalt Pavement
Holds heat longer (easier to roll), lifts can be placed in cooler weather, one lift is faster to place and more economical, and less distortion occurs
509
Asphalt Grades
Softer grades in cold climates (resists expansion), harder grades in warm climates (reduce rutting)
510
Performance Grading
ex: PG 64-22 (the high and low seven day average temp the asphalt will most likely experience in its lifetime)
**If the sum of these two numbers is above 90, should probably have a polymer modified asphalt
**Second number is negative and in celsius !!
511
Nominal Maximum Aggregate Size
The largest sieve that retains not more than 10% of the aggregate
512
Stability
Ability to resist permanent deformation
513
Concrete Slab Thickness
127 mm for lightly traveled streets. Influenced by Hveem's resistance values (R-values) or California Bearing Ratio (CBR)
514
Marshall Mix Design
Determines the optimal asphalt content. Disregards shear strength
515
Hveem Mix Design
Measures resistance to shear and considers asphalt absorption by aggregates. Basically want as much asphalt binder as possible without reducing stability
516
Superpave
Superior Performing Asphalt Pavement
- Level 1 mix design used by most highway agencies
- Level 2 mix design - measures primary mixture performance factors
- Level 3 is computer aided mix design
517
Structural Number Equation
SN = a1D1 + a2D2m2 + ...
SN is unknown but assumed to be 3 for low volume roads and 5 for high volume roads
518
ESALs over number of years
ESALS40 = ESALs (F|A, g%, 40)
519
Change in Pavement Serviceability Index
ΔPSI = p0 - pt
p0 = represents the actual ride quality of a new roadway
pt = the lowest pavement serviceability index before rehabilitation is needed (~2.5)
520
Recycled Asphalt Pavement (RAP)
Cost effective without sacrificing strength and reliability
521
Profiling
Surface recycling - modification of the visible surface of the pavement
522
Cold Planing
The removal of asphalt pavement by special pavement milling and planing machines. Creates even road surface and resistance to skidding
523
Cold in-place Recycling
Employs a cold train of equipment to mill 25-150 mm of pavement. Has at least 6% voids. Need roller compaction
524
Hot in-place Recycling
Heat pavement to 120 C, remove layer of 50 mm, can be used almost immediately after
525
Hot Mix Recycling
** Most Common
Removes existing asphalt pavement, hauls it to an offsite plant, and blends it with asphalt cement and virgin rock aggregate
526
Microwave Asphalt Recycling
Produces hot mix with 100% RAP
527
Subgrade Drains
applicable when:
1) high groundwater levels that reduce subgrade stability and provide a source of water for frost action
2) subgrade soils of silts and very fine sands that become quick or spongy when saturated
3) water seepage from underlying water-bearing strata
4) drainage path of higher elevations intercepts sag curves with low-permeability subgrade soils below
**should not be placed too close to the pavement. Roofing felt/ geotextile sleeves can be placed around drains for this purpose
528
Three Severity Categories
1) Property damage only (PDO) accidents
2) personal injuries
3) fatalities
529
Impact Attenuators
Used to provide crash protection at bridge pillars, center piers, etc. Usually have crash cushions
530
Roadside safety barrier types
Jersey barrier - 32" tall, 55 to 85 degrees
Ontario barrier - 42" tall
Constant slope barrier - 42" with slope of 79 degrees
F-shape barrier - jersey except different slope
Heavy vehicle median barrier - Reinforced version of the jersey barrier used in medians
**should not curve/ slope from from ground because can cause rollover
531
Design Driver
Encompasses a range of drivers whose differences and limitations are accounted for during road, vehicle, and traffic control designs
532
Perception-reaction time (PRT)
How quickly a driver can react to a situation (2.5s)
533
PIEV
- Perception - occurs when a driver sees a control device/object
- Identification - the nature of the perceived
- Emotion - encompasses a driver's decision-making process to take action
- Volition - executing action
** same as PRT
534
National Highway Work Zone Safety Program
Focuses on standardizing and evaluating to improve work zone safety. By FHWA
535
NCHRP 350
National Cooperative Highway Research Program Report 350; contains federal standards and guidelines for all work zone safety devices
536
Hydrologic Cycle
the full "life cycle" of water
537
Total Precipitation
Total Precipitation = initial abstraction + infiltration + surface runoff
538
Hydrograph
Plot of stream discharge versus time. Time base is the length of time that the stream flow exceeds the original base flow.
Flow rate increases on rising limb and decreases on falling limb
539
Stream discharge consists of...
surface runoff and subsurface groundwater flows
540
Straight line method
Draw a horizontal line from the start of the rising limb to the falling limb. Everything beneath this line is base flow
541
Fixed-base method
Base flow is projected until the crest of the hydrograph curve, then a horizontal line is drawn from crest point to falling limb.
542
Variable slope method
Slope of base flow before storm will match after storm. This occurs at an inflection point on the falling limb
543
Curve number
NCRS method to classify land use and soil type. Used to calculate total and peak runoff
544
Energy Equation Reminders
- open to atmosphere - pressure = 0!
- area doesn't change - v1=v2
- elevation doesn't change - z1=z2
- when coming from a large reservoir, the velocity at the surface of reservoir is approximately 0
545
Manning's Equation
Typically used to estimate the velocity of flow in any open channel
546
Hazen-Williams Equation
Commonly used for pipes flowing less than full. Table given in FE handbook for coefficients
547
Hydraulic Jumps
Occur when a supercritical flow changes rapidly to subcritical flow
548
Froude Number
Fr < 1, flow is subcritical
Fr = 1, critical
Fr > 1, the flow is supercritical
549
Well Drawdown
When an aquifer has a pump that begins to work, the GWT lowers in that vicinity and creates a cone of depression. The decrease in water level at some distance r from the well is known as the drawdown.
550
As Substance Concentration
the gravimetric amount of the substance in the volumetric water basis
551
Milliequivalent Concentration
the number of equivalent weights of the substance in the volumetric water basis times 1000 meq/eq
552
Equivalent Weight
the molecular weight divided by the oxidation number (valence, or number of charges on the ion)
EW = MW/valence
553
National Secondary Drinking Water Regulations
Protect the public WELFARE (not health); provide helpful guidelines regarding the taste, odor, color, and other aesthetic aspects of drinking water
554
Chloramines
When hypochlorous acid reacts with ammonia. Known as a combined residual
555
Average Annual Daily Flow (AADF)
the average number of gallons used by each person each day. minimum for planning is 165 gpcd (625 L/d)
556
Conventional (Complete) Filtration
describes the traditional sequence of adding coagulation chemicals, flash mixing, coagulation-flocculation, sedimentation, and subsequent filtration. Best for high turbidity, color, or impure waters
557
Algae Pretreatment
Can use copper sulfate to pretreat, but can be toxic to fish and other aquatic life
558
Flow Measurement
incorporated when water is conditioned enough to be compatible with measuring equipment (before chlorination). Takes place in a Parshall flume
559
Coagulants
Chemicals work by agglomerating particles in the water to form floc (precipitate that forms when the coagulant allows colloidal particles to agglomerate)
560
Hydrolyzing metal ion coagulants
Aluminum sulfate, ferrous sulfate, chlorinated copperas
561
Flocculator
a downstream location with a reduced velocity gradient
562
Flash (Rapid) Mixing
the basin volume is small, time for mixing is low
563
Rapid Sand Filters
are commonly used to filter out non-settling flocs, algae, suspended precipitates from softening, and metallic ions. Beds of gravel, sand, and other granulated materials.
564
Log-removal value
Logarithm of a concentration ratio:
1-log: 90%
2-log: 99%
3-log: 99.9%
4-log: 99.99%
565
Backwashing
needed when the pores between the filter particles clog up.
**used more frequently and is more aggressive when treating wastewater instead of water supply
566
Fluidized bed
A bed whose particles have been made to act like a fluid rather than a granular plug. Depth depends on the backflow velocity
567
Adsorbent
usually activated carbon. the medium where adsorption occurs
568
Recarbonation
After softening, this lowers the pH and reduces the scale-forming potential
569
Theoretical Detention Time (TDT)
the amount of time that it rakes for wastewater to pass though a tank
570
Baffling Factor (BF)
describes the degree of mixing (absence of short circuiting) within a basin
571
Distillation
the raw water is vaporized, leaving the salt and minerals behind
572
Nanofiltration
Softening membranes; similar to ultrafiltration and reverse osmosis with pore size and operating size between the two
573
Electrodialysis
positive and negative ions flow through selective membranes under the influence of an induced electrical current
574
Solute Flux
the rate at which solute is removed in a flow
575
Facultative Ponds
used in small communities; have an anaerobic lower zone, a facultative middle zone, and an aerobic upper zone. raw wastewater enters the center of the pond
576
Aerated Lagoon
a stabilization pond that is mechanically aerated. basis for design is based on organic loading or detention time. typically deeper and have shorter detention times than non-aerated ponds
577
Aerated Grit Chamber
a bottom-hoppered tank with a short detention time. keeps organic matter in suspension and capture grit
578
Chemical Flocculation
similar to the way that the operation in chemical sedimentation basins are for supply water, but coagulant doses are much higher.
```
aluminum sulfate
ferric chloride
ferric sulfate
ferrous sulfate
chlorinated copperas
```
579
Trickling Filters
beds of rounded river rocks, wood slats, or modern synthetic media. the biological slime growth on the bed purifies the wastewater as it trickles down
580
Recirculation
used to keep the filter medium from drying out and to smooth out fluctuations in the hydraulic loading. returning some of the collected filter water back to the filter
581
Rotating Biological Contactors (RBCs)
large diameter plastic disks, partially immersed in wastewater, on which biofilm is allowed to grow; removes organic solids from the wastewater
582
Phosphorous Removal (Precipitation)
soluble P is removed by precipitation and settling. dosage should be determined from testing
583
Ammonia Removal
- biological (nitrification and denitrification) - ammonia converted to nitrite --> nitrate --> nitrogen gas
- air stripping - lime added to water to increase pH to 10, changes it to NH3 (ammonia gas); air strips gas out of tower. Recarbonation after to remove excess lime
584
Breakthrough
when carbon becomes saturated with the target compound and can hold no more
585
Chlorination
disinfects and deodorizes; one of the final steps to discharge. contact tanks are baffled to prevent short circuiting that would reduce chlorination time and effectiveness
586
Dechlorination
Primarily use sulfur dioxide and sodium thiosulfate. used because toxicity, by-products, and strict limits on total residual oxidants (TROs) make dechlorination mandatory
587
Waste Activated Sludge (WAS)
The sludge that does not go back to feed the bacteria in the aeration tank. This is chlorinated and discharged
588
MLVSS
Mixed liquor volatile suspended solids
589
Food-to-microorganism ratio
F:M
590
Prevention of Significant Deterioration (PSD)
a program that is designed to protect air quality in clean-air areas that already meet the NAAQS
591
Nonattainment areas (NA)
areas that can't meet the NAAQS
592
Hazardous pollutants
compounds that pose particular, usually localized, hazards to exposed population (ex: asbestos, benzene, mercury, etc.)
593
Criteria pollutants
Ozone, CO, NO2, SO2, particulate matter, leads
594
Nitrogen Oxides
Emitted from motor vehicles, power plants, and other combustion operations.
Environmental Effects - visibility impairment, acidification of fresh water, increase of aquatic toxins, and change in vegetation.
Human - respiratory infection
595
Ozone
Formed by the reaction of volatile organic compounds (VOCs) and NOx in the presence of heat and sunlight
Human effects - respiratory infection, lung inflammation, chest pain, cough
Environmental - reduction in harvest yield, plant disease,
596
Acid Rain
A mixture of wet and dry atmospheric deposition containing higher than normal amounts of nitric and sulfuric acids
Environmental - acidification of soils, lakes and streams, corrosion of buildings, reduced visibility
597
Carbon Monoxide (CO)
Formed when carbon in fuel is not burned completely.
Atmospheric inversions occur when pollutants are trapped in a cold layer of air beneath a warmer one
Human - reduce oxygen delivery to the body, visual impairment, learning disability,
598
Smog
A mixture of pollutants and water; classic smog comes from large amounts of coal burning, while photochemical smog comes from a mixture of air pollutants and sunlight reacting
599
Lead
Comes from smelting, power plants fueled by coal, and oil shale production
Human - seizures, behavioral disorders
600
Radon
Formed by the natural decay of uranium
Human - lung cancer
601
PCBs
Polychlorinated Biphenyls (PCBs) are manufactured mixtures up to 209 individual chlorinated compounds
602
Particulate Matter (PM)
A complex mixture of extremely small particles and liquid droplets (acids, organic chemicals, metals, dust)
603
Sulfur Dioxide (SO2)
Produced in the combustion of coal or petroleum; can cause acid rain if oxidized
Human - respiratory illness, visibility impairment,
Environmental - acid rain, plant and water damage, damage to structures
604
Dioxins
PCDFs and PCDDs, TCDD. Form as a by-product of many industrial processes involving chlorine
605
Air Quality Index (AQI)
Developed by the EPA to quantify and describe the daily air quality for the general public. A higher AQI indicates lower air quality
AQI > 100 - unhealthy
606
Pollution Prevention
the process of reducing or eliminating waste at the source, modification of waste producing processes, use less toxic substances, conservation, reusing materials
607
as CaCO3
= C as substance * (EW CaCO3 which is 50)/(EW substance)
608
Ellipse
B^2 - 4AC < 0
609
Parabola
B^2 - 4AC = 0
610
Hyperbola
B^2 - 4AC > 0
611
Circle
B = 0 !
612
Orthogonal Vectors
A*B = 0 (A dot B = 0)
613
Parallel Vectors
AxB = 0 (Cross product of A and B is 0)
