bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Exposure Assessment: Basic Elements and Applications in Remedial Engineering Actions at Sites Containing Contaminated Soil and Groundwater
Authors: Dragun J , Erler TG 
Published: December 2008

When a soil or groundwater contamination problem is discovered, the attention of the public and of regulatory agencies focuses on the potential effects on human health. However, human exposure to a chemical at some minimal concentration must occur before an adverse effect on human health is realized. The exposure assessment quantifies this exposure; an exposure assessment is the determination or estimation of the magnitude, frequency, duration, and routes of exposure.
This paper addresses the basic elements and applications of the exposure assessment. First, this paper will define and discuss the six basic elements of an exposure assessment. Second, this paper will discuss the usefulness of the exposure assessment in evaluating remedial actions to be implemented at hazardous waste sites. Third, this paper presents an actual case study, involving an existing Superfund site, in which an exposure assessment was performed to select a cost-effective remedial action plan that provided the greatest benefit at an acceptable risk.
A Proposed In-Vivo/In-Vitro Approach to the Toxicological Assessment of Hazardous Waste
Authors: Lewtas J , Andon B 
Published: December 2008

An in-vivo/in-vitro toxicological screen has been developed to evaluate potentially hazardous waste samples and process stream residuals. The biological methods employed in the screen are designed to be rapid, cost-effective, and capable of screening large numbers of wastes. Emphasis is placed on identifying a wide range of potential toxic responses associated with each waste by employing diverse test methods. The toxic end points identified by the screen include mutagenesis/carcinogenesis, general toxicology, neurotoxicology, reproductive toxicology, teratology, and immunotoxicology.
The protocol, called the toxicological screen, involves the oral administration of waste material to male rodents for ten consecutive days. At the end of the ten-day period the whole animal, body tissues, and fluids are evaluated for toxicity. The toxicological screen also involves the oral treatment of pregnant rodents to wastes for ten consecutive days to assess transplacental effects and neonatal survival. A major goal of the toxicological screen is to maximize the amount and type of potential health effects information that can be obtained by exposing metabolically competent intact animals to complex waste mixtures.
The toxicological screen is being validated by using a series of positive (and negative) control compounds of known and defined toxicity. The validation study ensures that the protocol will be capable of detecting biologically active wastes and will allow assessment of the protocol's use as a predictive tool for known chronic effects. An additional goal of the validation study is to identify a subset of the assays from the toxicological screen that most readily detect the toxic potential of the positive control compounds. These selected assays will constitute a prescreen for the entire protocol. The prescreen can then be used as a rapid means of prioritizing waste samples to be evaluated in the full toxicological screen.
Initial trials of the validation study with four positive control compounds demonstrate the toxicological screen's ability to detect biologically active chemicals and to generate dose-response data.
Test Burns: A Critical Step in the Design of Hazardous Waste Incineration Systems
Authors: Santoleri JJ 
Published: December 2008

With the final implementation of the Resource Conservation and Recovery Act covering the disposal of hazardous wastes by incineration, certain basic criteria have been established. Most critical is the ability to reach levels of 99.99% destruction and removal efficiencies (DRE) of the principal organic hazardous constituents (POHC). In order to be assured that this is possible, a pilot test burn is necessary. If these wastes are presently being burned in a similar incineration system, the data can be used in the permit application.
However, there are many wastes which have been disposed of by landfill, land treatment, and chemical treatment that still present a hazard to our environment, and high-temperature oxidation is the only sure method of reaching destruction to four nines.
Test burns provide information for the proper design of the oxidizer related to air flow, fuel flow, oxidation temperature, mixing technique to achieve turbulence, atomizer type, residence time, and resultant emissions. Other problems inherent in handling the waste—such as pumping, piping, valving and control, atomization fluid and pressure, and atomizer location—are also encountered in the test burn and provide insight in the design of the full-scale system.
Certain control techniques which may be necessary for handling a variety of wastes are encountered in the test burn and provide the opportunity to check the effects of the unit operation.
The need for proper design and operation of a test burn facility will be discussed. Problem test burns will be reviewed and related to the effect on scale-up of full scale operating units. When a process changes, resulting in a different waste product, the pilot unit will permit testing and optimization of design without interruption of the full-scale system.
Finite-Element Analysis of Drilled Piers Used for Slope Stabilization
Authors: Oakland MW , Chameau JA 
Published: December 2008

During the past two decades, the use of bored piles, or drilled piers, has been shown on several occasions to be an effective deterrent to exessive slope movements. The technique is applicable when either the resisting forces of the slope are to be decreased or the driving forces to be increased. These situations arise when cutting a steeper slope or adding a surcharge above a slope, respectively. The movements of landslides can also be controlled by drilled-in piers or piles.
Several investigators have studied the problem of a single pier subject to lateral soil movement, given certain simplifying assumptions with regard to the soil model, soil-pile interface, and repartition of the lateral loads. It is commonly assumed that a plane strain condition prevails, and the piers are analyzed in two dimensions. This does not allow the effects of pier size and spacing to be represented, although finite-difference solutions have shown these to be very significant. Current design practice uses piers spaced closely together in a continuous barrier. Part of the face is usually exposed to form a retaining wall, and in some cases the piers are tied back at the top. The design methods are similar to those used for sheet-pile walls and usually valid for relatively shallow overburden depths. This methodology results in a conservative sizing and spacing of the piers.
In this paper a finite-element based methodology is proposed to model the three-dimensional effects involved in the stabilization of surcharged slopes with drilled piers. The soil is modeled with eight nodes, 24 degrees of freedom isoparametric elements. The piers are represented by three-dimensional spar elements. The program can be used to determine the effects of piers' position, size, spacing, and stiffness on slope movements. This program is the first step towards a more general methodology that will consider soil nonlinearity and creep, and make provisions for slippage around the pile.
Helical Anchor Piles Under Lateral Loading
Authors: Puri VK , Stephenson RW , Dziedzic E , Goen L 
Published: December 2008

Anchors are used in civil engineering practice to provide resistance against uplift and overturning forces for structures such as transmission line towers, aircraft mooring, pipelines, offshore structures, mobile homes, and so forth. Although there are a wide variety of anchor types available, helical screw anchors, consisting of a steel shaft to which one or more helices are attached by welding, are finding wider usage particularly for the support of transmission line towers. Because these anchors are installed by truck mounted power augurs they can be used immediately after installation.
Although there exists in the geotechnical engineering literature a variety of techniques for evaluating lateral-load capacity of piles, there are no published methods for analyzing helical anchor lateral stability when used as piling. The present study was undertaken to develop suitable mathematical models based upon the current state of the art for determination of lateral-load capacity of helical-type anchor piles. The model selected was patterned after Matlock and Reese's elastic theory model. The model was modified to take into account the influence of the method of installation and other unique characteristics of this type of foundation. Based on the results of this study it was found that helical anchor piles can develop significant resistance to lateral loads, and this resistance is almost exclusively controlled by the extension shaft diameter.
Fracture Mist Region in a Soda-Lime-Silica Float Glass
Authors: Ball MJ , Landini DJ , Bradt RC 
Published: December 2008

The mist region near the fracture origin was studied in a series of soda-limesilica float glass specimens ranging in strength from about 30 to 90 MPa. Both the mirror/mist and the mist/hackle radii were measured to ascertain the dependence of the width of the mist region on the strength level. The mirror/mist constant was found to be 1.80 ± 0.15 MN/m3/2 and the mist/hackle constant to be 2.42 ± 0.16 MN/m3/2. Both analytically and experimentally, the width of the mist region was found to be inversely related to the square of the fracture stress; that is, (Wmist) is proportional to (1/σf2). This suggests a dependence of the mist region width on the elastic strain energy at fracture initiation.
The surface topography of the mist region was analyzed by a scanning electron microscopy computerized contour mapping technique to determine the surface roughness within the mist region. It was observed that the average root-mean-square roughness in the mist region was proportional to the fracture stress squared. This suggests that the fracture surface roughness of the mist region, or alternatively the true surface area of the mist region, is also determined by the stored elastic strain energy in the specimen before fracture.
It is concluded that the mist region width and the mist region roughness are both determined by a strain energy criterion. It is suggested that they may be related through a generalized mist region parameter.
In-Pile Creep Strain and Failure of Cold-Worked Type 316 Titanium Pressurized Tubes
Authors: Boutard J-L , Maillard A , Carteret Y , Levy V , Boyer J-M 
Published: December 2008

The in-pile creep and failure behavior of cold-worked Type 316 titanium pressurized tubes irradiated in the same rig at temperatures ranging from 430 to 480°C to 650 to 700°C up to 81.4 dpaF (French displacements per atom) maximum in PHENIX are presented and compared to monitors.
At temperatures below 600°C, the in-pile hoop strains are consistent with the expected amount of irradiation creep. In the range of 650 to 700°C, the measured plastic strains are dose rate independent. This supports the assumption that the thermally controlled mechanisms dominate.
Examinations by fractography and optical micrography show that the failures are intergranular either in-pile or out-of-pile. In both cases, the damage consists of intergranular wedge cracks, and no cavitation can be observed by transmission electron microscopy.
The in-pile embrittlement that gives lower failure strain is to be associated with a decrease of the surface energy of grain boundaries rather than growth and coalescence of cavities.
Critical Assessment of Low-Fluence Irradiation Creep Mechanisms
Authors: Henager CH , Simonen EP 
Published: December 2008

A climb-controlled guide (CCG) creep model, which had been used to successfully rationalize low-fluence, light-ion irradiation creep data in pure nickel, accounted for low-fluence irradiation creep rates and loop growth rates in Type 316 stainless steel. The model also predicted a weak stress dependence and a weak temperature dependence in agreement with typical observations. Both light-ion and neutron irradiation creep measurements and microstructural observations at low fluences were examined and compared with predictions of the CCG model. Calculated creep rates compared to measured creep rates demonstrated that dislocation glide was the dominant mode of deformation during low-fluence creep when interstitial loops were small. When the interstitial loop radius approached one half the average dislocation glide distance, the dislocation glide contribution was small. The stress-induced preferred absorption (SIPA) creep mechanism contributed an increasing fraction of the total deformation as the loop radius increased and became dominant at fluences greater than 1 displacement per atom (dpa).
The CCG creep model assumes that glissile network dislocations intersect the small dislocation loop glide barriers, climb into a favorable orientation, and annihilate the loop through a Burgers vector reaction. Dislocation climb controls the rate of loop annihilation that allows dislocation glide between loop barriers. The creep rate is determined by a balance between irradiation-enhanced dislocation climb and interstitial loop growth.
Microsegregation Observed in Fe-35.5Ni-7.5Cr Irradiated in EBR-II
Authors: Brager HR , Garner FA 
Published: December 2008

In another recent study of the compositional dependence of swelling in annealed iron-nickel-chromium alloys, it was found that some annealed alloys densified during irradiation. No precipitate phases were observed to form, however. At 593°C, one alloy, Fe-35.5Ni-7.5Cr, which was particularly resistant to swelling, increased in density 0.9% at 7.6 × 1022 neutrons (n)/cm2 (E &gt; 0.1 MeV).
Examination by energy dispersive X-ray analysis revealed that substantial oscillations occur in the nickel content of the alloy, varying from 25 to 53% about the nominal level of 35.5%. These oscillations exhibit a period of ∼200 nm. Regions enriched in nickel are depleted in chromium and iron, and the reverse is true in regions of low nickel content. This spinodal-like process produces a net densification and also appears to eventually destroy the swelling resistance of the alloy. Once voids form in the nickel-poor chromium-rich regions, further segregation of nickel to void surfaces is expected to accelerate the loss of swelling resistance.
Some Observations on the Effect of Stress on Irradiation-Induced Swelling in AISI Type 316 Stainless Steel
Authors: Lauritzen T , Bell WL , Rosa JM , Vaidyanathan S 
Published: December 2008

An evaluation of the effect of stress on the swelling behavior of 20% cold-worked AISI Type 316 stainless steel was conducted. Beam specimens strained in a four-point bending mode during fast neutron irradiation in Experimental Breeder Reactor-II (EBR-II) were selected for this study. Peak elastic fiber stresses in the beams ranged from 140 to 320 MPa during irradiation to 8 × 1022 neutrons (n)/cm2 (E &gt; 0.1 MeV) at temperatures of 685 and 697 K. Regions of the beams corresponding to tensile, compressive, and neutral loading were examined by transmission electron microscopy (TEM) to evaluate the type, morphology, and distribution of irradiation-induced voids.
TEM revealed a fairly uniform distribution of voids throughout the lower temperature beam with little difference noted in void size, void density, or swelling. In the higher temperature beam, void densities increased by as much as a factor of two from the plane of zero stress—the central portion of the beam—to the tension and compression surfaces. This produced an increase in swelling relative to the neutral axis in both tension and compression regions, the latter showing a slightly lower swelling as the result of a somewhat smaller average void size. The general microstructure was that of a cold-worked material, with similar dislocation arrays in the three regions of the beams. Widely scattered faulted loops were detected but, because of their small size and density, no assessment regarding the influence of stress on such distributions was possible. However, there appeared to be no interaction between voids and dislocations and no encircling of voids with dislocation loops was noted.
Although the irradiation conditions in the present work produced extremely low levels of swelling with associated large uncertainties, the results suggest that swelling is enhanced by a tensile stress such as is produced in bending. Moreover, the results also indicate that a compressive stress similarly produced may also contribute to an increase in swelling.
Influence of Helium on Swelling of Steels
Authors: Levy V , Gilbon D , Rivera C 
Published: December 2008

In this work, we have studied the effect of helium and its injection mode on the microstructure of Type 316 and titanium-modified Type 316 stainless steels, both in their solution-annealed and cold-worked states. Irradiations have been conducted in a dual-beam accelerator to doses up to 150 dpa in a wide range of temperatures, from 550 to 750°C. Different injection modes have been investigated: cold preinjection, hot preinjection, and dual beam.
The results show that the effect of helium on swelling is largely dependent on the injection mode and also on the chemical composition of the alloy considered. In Type 316 steel, the presence of helium decreases swelling, the major effect being observed when helium is preinjected at room temperature. In titanium-modified steels, if a high density of tiny helium bubbles are present in all the specimens containing helium, void swelling only occurs for dual-beam irradiations.
In conclusions, this work shows that the effect of helium on void swelling depends on its injection mode, but also that the sense of this effect is clearly different when comparing the behavior of a low and a high swelling alloy.
Radiation Thermometry—Status and Trends
Authors: Barron WR , Goldberg AE 
Published: December 2008

The use of radiation thermometry has expanded over the past five years and applications will increase to meet new industrial demands and the addition of new technologies. There is the full product spectrum from portables to transmitters to closed loop control systems. Tailored designs also are being developed involving dual wavelength sensors, multihead systems, fiber-optic sensors, and hybrid designs to measure aluminum.
This paper summarizes the present and future trends in radiation thermometry. Instrument development will continue as user demands for accurate product temperature measurements are uncovered.
A Review of Temperature Measurement in the Steel Reheat Furnace
Authors: Martocci AP , Mihalow FA 
Published: December 2008

The incentive for conducting research and development on reheat furnaces is substantial; the domestic steel industry spent approximately one billion dollars on fuel in reheat furnaces in 1981. Bethlehem Steel Corp. spent $145 million of that total, and neither figure includes fuel consumed in soaking pits or annealing furnaces. If we set a goal to save 10% of these annual fuel costs, that translates into $100 million for the domestic steel industry and $14.5 million for Bethlehem Steel. These large sums of money are significant incentives.
The purpose of this paper is to review the historical heating practices and equipment at steel reheat furnaces along with current practices and instrumentation.
Thermal Insulation Materials: Generic Types and Their Properties
Authors: Lang GE 
Published: December 2008

Thermal insulation plays a very important function in all of our lives. Without it the cost of energy used in our homes would skyrocket, perishable foods would be available only within a short distance of the source, plastic items and many petroleum products would not exist, and we would have to get used to warm beer and soupy ice cream.
Now to the generic and functional differences of the various types of thermal insulation. One of the most defining properties of a thermal insulation is its service temperature range. Since we are discussing generic types of insulation, and some manufacturers' recommended service temperatures vary slightly, the du Pont Company's established recommended service temperatures are listed in the paper. The properties, good and bad, of generic thermal insulation materials that have a bearing on their individual influence on corrosion of the metals they cover will be discussed.
Controlling Carbon Steel Corrosion Under Insulation
Authors: Krystow PE 
Published: December 2008

Corrosion under hot and cold thermal insulation can be a serious problem in chemical plants. Not only has corrosion under insulation caused staggering maintenance costs in the millions of dollars but also has led to lost production time as well as affected plant safety. Many of the chemical plants have experienced a variety of problems and some of the specific experiences will be described in this symposium.
As a result, Exxon Chemical Company and many other chemical companies have embarked on a major effort to address the problem. In a companion paper, Exxon Chemicals at Baton Rouge will describe identifiable factors that cause the problem. This paper will review the important steps that Exxon Chemical has taken to control carbon steel corrosion under insulation. Specifically, the review will include (1) organizing and scheduling more rigorous programs of inspection including typical examples, (2) preparation of improved insulation specifications that address each of the factors affecting corrosion, and (3) action programs required to assure that improved insulation specifications are implemented.
An important aspect of controlling corrosion under insulation is through an appropriate inspection program. Unfortunately under normal circumstances, inspection requires the removal of the insulation during downtime, which is both costly and extremely difficult particularly on large towers and complex piping systems. There is an urgent need to develop a nondestructive onstream examination (NDE) method to detect corrosion without removal of insulation. In this connection, the Materials Technology Institute for the Chemical Process Industries is investigating some of the NDE methods. A brief synopsis will be made of the NDE methods employed. However, these methods have had only limited success, and a breakthrough inspection method is still needed. This need for breakthrough represents an important challenge to the international scientific community.
Prevention of Chloride Stress Corrosion Cracking Under Insulation
Authors: Sumbry LC , Vegdahl EJ 
Published: December 2008

Chloride stress corrosion cracking of stainless steel under insulation can occur because of concentration of chlorides at the metal surface. This paper discusses our company's current recommended practices for controlling this type of corrosion and results of a research program to improve our recommended practices.
Our current recommended practice for controlling corrosion of stainless steel under insulation is to select insulation materials low in extractable chlorides, jacket or coat insulation to exclude water and chlorides from the environment, and to coat the stainless steel equipment where applicable. Coating stainless steel to prevent contact with chlorides is recommended with some reservation because of generally poor experience in coating stainless steel equipment.
A research program is being conducted on coatings for stainless steel equipment. A variety of coatings have been evaluated using adhesion and flexibility tests, outdoor exposure, salt fog cabinet, environmental cabinet containing hydrogen sulfide, carbon dioxide, nitrogen dioxide, and wet air, a Weatherometer cabinet, elevated temperature exposure (260 to 500°C), thermal shock tests, and chloride permeability tests. Adhesion to stainless steel is generally fair. For elevated temperature applications, straight silicones are generally superior. Many coatings are adequate for ambient temperature applications if protected from mechanical damage.