bluuebunny/crossref_metadata_2025 huggingface dataset:
The susceptibility of Anopheles lesteri to infection with Korean strain of Plasmodium vivax
Authors: Joshi Deepak , Choochote Wej , Park Mi-Hyun , Kim Jung-Yeon , Kim Tong-Soo , Suwonkerd Wannapa , Min Gi-Sik
Published: March 2009

Background

Following its recent re-emergence, malaria has gained renewed attention as a serious infectious disease in Korea. Three species of the Hyrcanusgroup,Anopheles lesteri, Anopheles sinensisandAnopheles pullus, have long been suspected malaria vectors. However, opinions about their vector ability are controversial. The present study was designed with the aim of determining the susceptibility of these mosquitoes to a Korean isolate ofPlasmodium vivax. Also,An. sinensisis primarily suspected to be vector of malaria in Korea, but in Thailand, the same species is described to have less medical importance. Therefore, comparative susceptibility of Thai and Korean strains ofAn. sinensiswith Thai strain ofP. vivaxmay be helpful to understand whether these geographically different strains exhibit differences in their susceptibility or not.

Methods

The comparative susceptibility ofAn. lesteri,An. sinensisandAn. pulluswas studied by feeding laboratory-reared mosquitoes on blood from patients carrying gametocytes from Korea and Thailand.

Results

In experimental feeding with Korean strain ofP. vivax, oocysts developed inAn. lesteri,An. sinensisandAn. pullus. Salivary gland sporozoites were detected only inAn. lesteriandAn. sinensisbut not inAn. pullus. Large differences were found in the number of sporozoites in the salivary glands, withAn. lestericarrying much higher densities, up to 2,105 sporozoites in a single microscope field of 750 × 560 μM, whereas a maximum of 14 sporozoites were found in any individual salivary gland ofAn. sinensis. Similar results were obtained from a susceptibility test of two different strains ofAn. sinensisto Thai isolate ofP. vivax, and differences in vector susceptibility according to geographical variation were not detected.

Conclusion

The high sporozoite rate and sporozoite loads ofAn. lesteriindicate that this species is highly susceptible to infection withP. vivax.Anopheles sinensisappears to have a markedly reduced ability to develop salivary gland infection, whilst inAn. pullus, no sporozoites were found in the salivary glands. Provided that the survival rate ofAn. lesteriis sufficiently high in the field, it would be a highly competent vector of vivax malaria.
Increased expression of heat shock protein 105 in rat uterus of early pregnancy and its significance in embryo implantation
Authors: Yuan Jin-Xiang , Xiao Li-Juan , Lu Cui-Ling , Zhang Xue-Sen , Liu Tao , Chen Min , Hu Zhao-Yuan , Gao Fei , Liu Yi-Xun
Published: March 2009

Background

Heat shock proteins (Hsps) are a set of highly conserved proteins, Hsp105, has been suggested to play a role in reproduction.

Methods

Spatio-temporal expression of Hsp105 in rat uterus during peri-implantation period was examined by immunohistochemistry and Western blot, pseudopregnant uterus was used as control. Injection of antisense oligodeoxynucleotides to Hsp105 into pregnant rat uteri was carried out to look at effect of Hsp105 on embryo implantation.

Results

Expression of Hsp105 was mainly in the luminal epithelium on day 1 of pregnancy, and reached a peak level on day 5, whereas in stroma cells, adjacent to the implanting embryo, the strongest expression of Hsp105 was observed on day 6. The immunostaining profile in the uterus was consistent with that obtained by Western blot in the early pregnancy. In contrast, no obvious peak level of Hsp105 was observed in the uterus of pseudopregnant rat on day 5 or day 6. Furthermore, injection of antisense oligodeoxynucleotides to Hsp105 into the rat uterine horn on day 3 of pregnancy obviously suppressed the protein expression as expected and reduced number of the implanted embryos as compared with the control.

Conclusion

Temporal and spatial changes in Hsp105 expression in pregnant rat uterus may play a physiological role in regulating embryo implantation.
α-Melanocyte-Stimulating Hormone Counteracts the Suppressive Effect of UVB on Nrf2 and Nrf-Dependent Gene Expression in Human Skin
Authors: Kokot Agatha , Metze Dieter , Mouchet Nicolas , Galibert Marie-Dominique , Schiller Meinhard , Luger Thomas A. , Böhm Markus
Published: March 2009

Human skin is constantly exposed to UV light, the most ubiquitous environmental stressor. Here, we investigated the expression and regulation of Nrf1-3, transcription factors crucially involved in protection against oxidative stress in human skin cells in vitro, ex vivo, and in situ. In particular, we examined whether α-MSH, a UV-induced peptide, is capable of modulating Nrf2 and Nrf-dependent gene expression. Nrf1, -2, and -3 were found to be expressed in various cutaneous cell types in vitro. Surprisingly, UVB irradiation at physiological doses (10 mJ/cm2) reduced Nrf2 and Nrf-dependent gene expression in normal keratinocytes and melanocytes in vitro as well as ex vivo in skin organ cultures. α-MSH alone significantly increased Nrf2 as well as Nrf-dependent heme oxygenase-1, γ-glutamylcysteine-synthetase, and glutathione-S-transferase Pi gene expression in both keratinocytes and melanocytes. This effect of α-MSH occurred at physiological doses and was due to transcriptional induction, mimicked by the artificial cAMP inducer forskolin, and blocked by protein kinase A pathway inhibition. In silico promoter analysis of Nrf2 further identified several putative binding sites for activator protein 1 and cAMP response element-binding protein, transcription factors typically activated by α-MSH. Importantly, α-MSH prevented or even overcompensated the UVB-induced suppression of Nrf2 and Nrf-dependent genes not only in normal keratinocytes and melanocytes in vitro but also in skin organ cultures. These findings, for the first time, show regulation of Nrf2 and Nrf-dependent genes by α-MSH. Our data also highlight a novel facet in the cytoprotective and antioxidative effector mechanisms of α-MSH and perhaps of related melanocortin peptides.
Mechanisms of Protein Kinase C Signaling in the Modulation of 3′,5′-Cyclic Adenosine Monophosphate-Mediated Steroidogenesis in Mouse Gonadal Cells
Authors: Manna Pulak R. , Huhtaniemi Ilpo T. , Stocco Douglas M.
Published: March 2009

The protein kinase C (PKC) signaling pathway plays integral roles in the expression of the steroidogenic acute regulatory (StAR) protein that regulates steroid biosynthesis in steroidogenic cells. PKC can modulate the activity of cAMP/protein kinase A signaling involved in steroidogenesis; however, its mechanism remains obscure. In the present study, we demonstrate that activation of the PKC pathway, by phorbol 12-myristate 13-acetate (PMA), was capable of potentiating dibutyryl cAMP [(Bu)2cAMP]-stimulated StAR expression, StAR phosphorylation, and progesterone synthesis in both mouse Leydig (MA-10) and granulosa (KK-1) tumor cells. The steroidogenic potential of PMA and (Bu)2cAMP was linked with phosphorylation of ERK 1/2; however, inhibition of the latter demonstrated varying effects on steroidogenesis. Transcriptional activation of the StAR gene by PMA and (Bu)2cAMP was influenced by several factors, its up-regulation being dependent on phosphorylation of the cAMP response element binding protein (CREB). An oligonucleotide probe containing a CREB/activating transcription factor binding region in the StAR promoter was found to bind nuclear proteins in PMA and (Bu)2cAMP-treated MA-10 and KK-1 cells. Chromatin immunoprecipitation studies revealed that the induction of phosphorylated CREB was tightly correlated with in vivo protein-DNA interactions and recruitment of CREB binding protein to the StAR promoter. Ectopic expression of CREB binding protein enhanced CREB-mediated transcription of the StAR gene, an event that was markedly repressed by the adenovirus E1A oncoprotein. Further studies demonstrated that the activation of StAR expression and steroid synthesis by PMA and (Bu)2cAMP was associated with expression of the nuclear receptor Nur77, indicating its essential role in hormone-regulated steroidogenesis. Collectively, these findings provide insight into the mechanisms by which PKC modulates cAMP/protein kinase A responsiveness involved in regulating the steroidogenic response in mouse gonadal cells.
EGFR and K-ras Mutations Along the Spectrum of Pulmonary Epithelial Tumors of the Lung and Elaboration of a Combined Clinicopathologic and Molecular Scoring System to Predict Clinical Responsiveness to EGFR Inhibitors
Authors: Sartori Giuliana , Cavazza Alberto , Sgambato Alessandro , Marchioni Alessandro , Barbieri Fausto , Longo Lucia , Bavieri Mario , Murer Bruno , Meschiari Emmanuela , Tamberi Stefano , Cadioli Annamaria , Luppi Fabrizio , Migaldi Mario , Rossi Giulio
Published: March 2009

We tested 418 neoplasms along the whole spectrum of primary lung tumor histotypes for epidermal growth factor receptor (EGFR) and K-ras mutations. Clinicopathologic data from 154 patients undergoing treatment with EGFR tyrosine kinase inhibitors (TKIs) were retrospectively studied. A scoring system assigning a score for each positive or negative characteristic (+1, female sex, nonsmoking status, adenocarcinoma histotype, Asian ethnicity, and EGFR mutation; −1, current smoker and K-ras mutation; and 0, male sex, ex-smoker, nonadenocarcinoma histotype, and no mutations) was elaborated and tested with EGFR-TKI response.

Salivary gland–type, mucin-rich, and neuroendocrine tumors do not harbor EGFR mutations. A subset of nonmucinous adenocarcinomas, not necessarily of the bronchioloalveolar type, is related to EGFR mutations. Three probability groups significantly correlating with response to EGFR-TKIs were identified. Of note, the addition of molecular results did not significantly change the predictive value obtained by the combination of clinicopathologic characteristics alone in this scoring system.

K-ras mutations, significantly associated with the mucin-secreting type of adenocarcinoma, consistently predict lack of response in white patients.
Usefulness of EMA, GLUT-1, and XIAP for the Cytologic Diagnosis of Malignant Mesothelioma in Body Cavity Fluids
Authors: Shen Jian , Pinkus Geraldine S. , Deshpande Vikram , Cibas Edmund S.
Published: March 2009

We compared the effectiveness of epithelial membrane antigen (EMA) with 2 newly described markers, X-linked inhibitor of apoptosis protein (XIAP) and an isoform of glucose transporter (GLUT-1), in the distinction between malignant mesothelioma (MM) and benign effusion (BE) in body cavity fluids. Immunohistochemical studies were performed on cell block sections from 35 cases of histologically confirmed MM and 38 BEs, using antibodies to EMA, XIAP, GLUT-1 (GLUT-1m, monoclonal; GLUT-1p, polyclonal). Results were graded based on the percentage of cells staining: negative (0%), 1+ (<25%), 2+ (25%–49%), 3+ (50%–74%), and 4+ (75%–100%). The performance of each marker was compared using receiver operating characteristic curve analysis. EMA demonstrated the best accuracy, with an area under the curve of 0.91 as compared with XIAP (0.67), GLUT-1m (0.74), and GLUT-1p (0.80). Based on these findings, EMA is a better marker than XIAP or GLUT-1 for the diagnosis of MM.
Patriarchy: The Predominant Discourse and Fount of Domestic Violence
Authors: Bettman Cathy
Published: March 2009

While supporting the need to make class and other forms of marginalisation more visible in the understanding of, and response to, domestic violence, this article argues that, domestic violence is ultimately a discursive phenomenon and that patriarchal discourse remains the fount of domestic violence. This conclusion was drawn after data from a qualitative study of 24 men, from different cultural groups (ethnic, religious, racial, age and class), who had used violence in an intimate heterosexual relationship was considered, alongside ethnographical accounts of societies in which domestic violence is deemed not to have occurred, or to have been minimal. Whereas egalitarian and respectful attitudes towards women are enshrined in the discourse and social institutions of tribes such as the Semai and Waorani, in which intimate partner violence was absent, the most overwhelming discovery of the qualitative study was that class and cultural differences, evident in an analysis of the men's narratives, seemed to be eclipsed by the preeminence and strength of gendered discourse, in keeping with Western patriarchal dictates.
Characterization of Surfaces in Wear Tests
Authors: Eiss NS
Published: March 2009

Models for the abrasive wear of polymers have identified several surface topography parameters which significantly influence the wear process: the average slope of the asperities, the peak curvature, the bearing area curve, and the autocorrelation length. Because the values of these parameters depend on the profile length and the reference used for the height data, there is no unique set of values for the parameters which describe a surface. For each surface which will be used in contact with another, the dimension of the contact area in the direction of sliding must be determined. The profile length should be set equal to this dimension.
Evaluation of PV Limits for Plastic Bearing Materials
Authors: Ludema KC
Published: March 2009

Polymeric bearing materials are usually operated below a limit of sliding severity expressed as the PV limit, where P is the average contact pressure and V is the surface sliding speed. In principle the PV limit should relate to the occurrence of melting on the polymer surface but cannot be derived from the physical properties of the polymer. The thermal properties of the counterface material and the manner of formation of transfer film appear to be as important in controlling the rate of wear as the softening temperature of the polymer. The influence of surface finish is not yet clear.
Predicting Polymer Serviceability for Wear Applications
Authors: Grove TH , Budinski KG
Published: March 2009

The following limitations of present polymer wear tests are discussed: it is difficult to get feedback on service life tests; pressure-velocity (PV) and wear (K) factor tests ignore counterface wear and geometry and are best used only for “internal screening;” and standard wear tests are limited in number and scope of applicability.

The suggested approach for predicting the wear of polymers is to use published wear data for screening candidate materials and then conduct simulative tests duplicating as many operating parameters as is practical. A case history of a bearing development project is presented to illustrate this approach.
Disposal of Oily Waste from Oil Spills by Land Farming
Authors: Wahbeh N
Published: March 2009

The Vector Control Division of the California State Department Health Services issues the guidelines and regulations that classify the industrial waste into hazardous and extremely hazardous [1]. California State law requires that the hazardous and extremely hazardous waste must be disposed of in Class 1 disposal sites. Oily waste generated from oil spills is considered hazardous to the environment and must be disposed of in Class 1 disposal sites. A Class 1 disposal site has to meet certain requirements [2] set by the State Water Resources Control Board and other regulatory agencies.

Sometimes the recovery and recycling of oily waste from oil spills is uneconomical, and our experience so far has proved that land farming of oily waste is one of the most economical methods to dispose of this type of waste. The decomposition of petroleum products by microorganisms is an established fact, and the top layer of the soil is heavily populated with these microorganisms such as Pseudomonas and Nocardia. Climatic conditions such as temperature, type of soil, and rainfall determine the design and operating conditions of the land farming operations. The use of the proper mixing equipment to provide adequate aeration for the biodegradation process is of prime importance.

IT Corporation has 30 years of experience in the field of disposal and treatment of chemically hazardous waste. In the past seven years, the company has acquired two large disposal sites that facilitated the acceptance of large volumes of petroleum waste that contains unrecoverable hydrocarbons.

After two years of experimental work in small lots, based on information obtained from published literature [3–11], the company decided to adopt a large-scale land farming operation.
The Oily Debris Disposal Problem in Maine
Authors: Aho H , Guerin M
Published: March 2009

This paper examines the problems of oil spill debris disposal encountered in the State of Maine. As well documented in many other states, the final disposition of oil spill debris is not an easy task. In Maine, this problem is compounded by geological, hydrological, and seasonal variations. To make matters even more difficult, recent contamination of groundwaters in several towns has caused the general public to view oil spill debris disposal sites in a negative light.

This paper addresses the aforementioned conditions and the problems they cause in finding an acceptable oily waste disposal site. These objectives are to be accomplished by: (a) discussing the physical and sociological problems encountered in attempting to create an acceptable disposal site which will not endanger the environment, (b) discussing the historic and present methods of disposal, and (c) discussing proposed plans for future disposal sites, including an examination of several present day disposal methods and how it is believed they might work in Maine.

This paper has been written in order to give an objective view of the problems of disposal site location encountered in Maine. It is hoped that other states, with similar problems, may gain insight from it.
An In Situ Experimental Method for Toxicological Studies on Natural Plankton Communities
Authors: Marshall JS , Mellinger DL
Published: March 2009

During 1976 and 1977, the authors developed and tested a new in situ method for toxicological studies on natural plankton communities using small-volume (8- and 25-litre) enclosures. The effects of enclosure for 4 to 21 days on the plankton in northern Green Bay, Lake Michigan, were studied in connection with cadmium addition experiments. In situ incubations in opaque enclosures or in translucent ones at depths of >8 m caused large changes in the zooplankton community structure, as measured by two similarity indexes, the coefficient of community (CC) and the percentage similarity (PS), whereas incubations in translucent enclosures at 3 to 8 m caused relatively small changes. The effect of cadmium additions (0 to 5 µg cadmium per litre) on total zooplankton abundance in translucent enclosures at 3 to 5 m was significantly greater than in those at 6 to 8 m. This interaction between cadmium and light (depth) was probably due to a reduction of phytoplankton photosynthesis, as indicated by changes in dissolved oxygen (DO) concentrations. Zooplankton abundance was not significantly affected by <1.6 µg cadmium per litre, whereas DO and PS were significantly reduced by ≥0.2 µg cadmium per litre. Values of PS for zooplankton communities in large-volume (1.5 × 105 litre) enclosures in a small Canadian lake in northwestern Ontario 3 weeks after the addition of cadmium were within the 95 percent confidence limits predicted from the results of 3-week experiments in Lake Michigan.
A Dynamic Viscoelastic Analysis of Crack Propagation and Crack Arrest in a Double Cantilever Beam Test Specimen
Authors: Popelar CH , Kanninen MF
Published: March 2009

Studies of dynamic crack propagation and arrest in polymeric materials are generally interpreted using rate-independent elastic analyses. To ascertain the importance of the viscoelastic constitutive behavior exhibited by polymers that is neglected in these approaches, a simple mathematical model for dynamic viscoelastic crack propagation in wedge-loaded double cantilever beam (DCB) test specimens has been developed. Computational results have been obtained for four different polymers using a three-parameter solid linear viscoelastic constitutive representation. In comparing these results with rate-independent elastic behavior, it is found that significant differences in the crack propagation/arrest process do exist. However, close correlations can nevertheless be obtained if, in displaying experimental results, proper account is taken of the viscoelastic properties.
Influence of Specimen Geometry on Crack Propagation and Arrest Toughness
Authors: Dahlberg L , Nilsson F , Brickstad B
Published: March 2009

A number of crack propagation experiments on four different specimen geometries were performed in order to investigate the existence of a unique relationship between crack propagation toughness and crack-tip velocity. For one geometry, dynamic finite-element method (FEM) calculations were found to be necessary in order to obtain proper stress-intensity factors, whereas quasi-static FEM-calculations were found to be sufficient for the other geometries. Crack-tip velocities were determined from continuous recordings of crack length versus time, which was measured by an impedance method. The stress-intensity factor and the instantaneous crack-tip velocity were obtained for a number of crack lengths for each experiment. The experimental results do not contradict the hypothesis of a unique relationship between these two quantities at low load levels; neither do they contradict the hypothesis of a geometry-independent crack arrest toughness. At high load levels a deviation from the uniqueness was observed. The height of the specimens was found to influence the crack propagation toughness level at the beginning of deviation from the unique relationship.
Comparison of Crack Behavior in Homalite 100 and Araldite B
Authors: Metcalf JT , Kobayashi T
Published: March 2009

Currently, two polymeric materials, Homalite 100 and Araldite B, are extensively utilized in the study of dynamic fracture. Homalite 100 is employed in the dynamic photoelastic studies of Dally et al of the University of Maryland, and Kobayashi et al of the University of Washington. They have determined the instantaneous stress-intensity factor from the isochromatic fringe loops and have studied the influence of specimen geometry on crack propagation and arrest, postarrest oscillations, and K-versus-˙a relationships.

Araldite B is employed by Kalthoff et al of the Institüt für Festköpermechanik of the Federal Republic of Germany. In their study of dynamic fracture with Araldite B, however, the instantaneous stress-intensity factor is determined by the method of shadow patterns (caustics). The results of photoelastic studies with Homalite 100 and caustic studies with Araldite B show good agreement in some areas, but disagreement in other areas. Since dynamic fracture behavior is studied with two different materials and two different methods, it is difficult to determine whether the points of disagreement are due to material properties or experimental method.

This paper presents the results of a characterization of the physical and mechanical properties and photoelastic observations of dynamic crack behavior of Homalite 100 and Araldite B. Also presented are detailed observations of the differences in fracture surface features of the two materials, and a discussion of the effect of material properties and specimen geometry on crack propagation, crack arrest, and postarrest oscillation.
Some Effects of Specimen Geometry on Crack Propagation and Arrest
Authors: Gates RS
Published: March 2009

Fast crack propagation and arrest have been studied in steel specimens of the double cantilever beam type using three different geometries and either a fixed grip or compliant loading system. A finite-difference computer program was used to measure values of the dynamic stress-intensity factor KD. The relationship between values of KD and KS, the stress-intensity factor for a quasi-statically growing crack depended on the specimen geometry and loading system used.

Stable crack arrest was easier to obtain in the specimens loaded with fixed grips. This probably resulted from the rigidity of the loading system, which produced specimen oscillations after arrest of insufficient magnitude to reinitiate crack growth. An examination of the energy associated with a moving crack suggests that kinetic energy may be reabsorbed to aid further crack propagation but is not all reabsorbed at arrest. The remaining fraction causes oscillations of the cracked specimen halves which may reinitiate the crack, or be damped out as the stress intensity rings down to its static value. Examination of the data suggests that intermediate arrests, characterized by a minimum in the crack length velocity curve, were a common feature of all tests. The stress intensity for crack arrest appeared to depend on specimen geometry.
Fast Fracture Toughness and Crack Arrest Toughness of Reactor Pressure Vessel Steel
Authors: Hahn GT , Hoagland RG , Lereim J , Markworth AJ , Rosenfield AR
Published: March 2009

Crack propagation and arrest measurements have been made using six pressure vessel steels and a submerged-arc weldment. The base-metal crack arrest toughness, KIm, is found to increase linearly with temperature above nil-ductility transition (NDT), and between NDT and (NDT + 100°C) is substantially greater than KIR. NDT is found to be a more consistent reference temperature than room temperature NDT (RTNDT). It is suggested that the absolute value of KIm at any temperature is composed of cleavage and dimpled-rupture contributions, with regions of dimpled rupture being contained in shear walls normal to the crack plane and parallel to the direction of crack travel. Shear walls which do not completely fracture are the source of unbroken ligaments observed on the fracture surface. The arrest toughness of the weldment is significantly lower than that of the baseplate and displays little evidence of unbroken ligaments or shear walls.
A Theoretical Model for Crack Propagation and Crack Arrest in Pressurized Pipelines
Authors: McGuire PA , Sampath SG , Popelar CH , Kanninen MF
Published: March 2009

The further development of a mathematical model for steady-state crack propagation in a pressurized pipeline is described. A key parameter in the model—the location of the plastic yield hinge relative to the moving crack tip—was determined by forcing agreement with crack speeds observed in the full-scale line pipe tests. The maximum crack driving force predicted by the model was then taken as a measure of the minimum fracture toughness value required for crack arrest. Comparisons with existing empirical formulations derived by Battelle, the American Iron and Steel Institute, British Steel, and the British Gas Council for the minimum required toughness values for crack arrest were made to demonstrate the reasonableness of this approach.
Degradation of Metal-Fiber-Reinforced Concrete Exposed to a Marine Environment
Authors: Rider R , Heidersbach R
Published: March 2009

The object of this research was to determine the effects of a marine environment on the integrity of metal-fiber-reinforced concrete. Metal-fiber-reinforced concrete has potential for uses in marine structures where the metal fiber may introduce tensile strength, abrasion resistance, and fatigue properties which may justify the added cost when compared with conventional concrete. Metal-fiber-reinforced concrete specimens were tested in flowing seawater and freshwater laboratory exposures. Comparisons were made to specimens exposed in the tidal zone of Narragansett Bay. Freeze-thaw experiments were also conducted. Results were obtained using standard and modified ASTM testing procedures as well as electrochemical corrosion rate monitoring techniques. The results indicate that stainless steel fibers are needed in marine applications.
Prediction Model for Fatigue Crack Growth in Windmill Structures
Authors: Finger RW
Published: March 2009

The 30-year life requirement of the Boeing Mod II windmill results in a service life load spectrum having an excess of 200 million cycles. Determination of allowable stress levels for the type of steels being used in construction of the systems, requires a detailed knowledge of their crack growth behavior under representative spectrum. A spectrum load test program was conducted, using uniaxially loaded surface flaw specimens, to provide the data needed to ascertain the impact of differences in load spectra on crack growth behavior.

A total of four different load spectra were tested to provide enough diversity in test parameters to ensure that the actual load spectra for the system would be enveloped by those tested. The test results were analyzed using different crack growth models to determine which produced the best correlation between actual and predicted results. Excellent correlation between predicted and actual test results was obtained when a crack growth model containing both a threshold and retardation term was used. This model can be used to estimate the spectrum load crack growth behavior of steels covered by the ASTM Specification for General Requirements for Rolled Steel Plates, Shapes, Sheet Piling, and Bars for Structural Use (A 6–76a) and Specification for General Requirements for Steel Plates for Pressure Vessels (A 20–76b).
Infrasonic Measurement of Building Air Leakage: A Progress Report
Authors: Card WH , Sallman A , Graham RW , Drucker EE
Published: March 2009

This research compares a new infrasonic method with the conventional blower method for determining the composite effective size of all the air-leakage passages in a house or apartment. In the frequency range used (0.1 to 7 Hz) small buildings are characterized mainly by one acoustic capacitance and one nonlinear leakage resistance. Infrasonic apparatus comprising a motor-driven source having known output, a sensitive pressure pickup, and an electronic signal processor has been constructed and used to measure leakage from several apartments and a house. Under field conditions the results of the infrasonic and blower measurements agree within a factor of two or three. Since the infrasonic system requires no through-the-wall blower vent or pressure taps, it is easier to set up than a blower system.
Analysis of Trace Metals and Cyanide in Complicated Waste Matrices
Authors: El-Beck WK , Miller ML
Published: March 2009

The analysis for soluble heavy metals and cyanide in waste materials and other complex matrices can be assisted by the use of chloroform. Chloroform was used in a test procedure designed to simulate codisposal of waste with municipal refuse. Chloroform was found to be effective in removing interferences to metals analysis.
Elemental Composition of Simulated In Situ Oil Shale Retort Water
Authors: Fox JP
Published: March 2009

This paper presents the abundances of 47 elements in 23 unfiltered retort waters from three simulated in situ retorts and of 17 elements in the dissolved and particulate fraction of 11 of these waters. This work indicates that for most of the unfiltered waters, the carbon, hydrogen, nitrogen, and sulfur occur at concentrations greater than 0.1 percent; that aluminum, arsenic, calcium, iron, potassium, sodium, nickel, and chlorine occur at concentrations greater than 1 ppm and less than 0.1 percent; and that all other measured elements occur at concentrations of less than 1 ppm. The particulate fraction in these waters ranges from 203 to 2984 mg/litre, and, in most waters, iron, nickel, potassium, and calcium occur at concentrations that are greater than 0.1 mg/litre. (Carbon, hydrogen, nitrogen, and sulfur were not measured in the particulates.) All other measured elements (titanium, vanadium, chromium, manganese, gallium, arsenic, selenium, bromine, rubidium, strontium, yttrium, mercury, and lead) typically occur at concentrations of less than 0.05 mg/litre in the particulates. About 1 percent of the total elemental mass of potassium, arsenic, and selenium occurs in the particulates, while significantly greater than 1 percent of the elemental mass of iron, chromium, mercury, and nickel may be present as particulate matter. The dissolved metal content of some waters was significantly reduced during filtration by crystallization and bacterial uptake.
Paraho Waters—Characteristics and Analysis of Major Constituents
Authors: Wildeman TR , Hoeffner SL
Published: March 2009

Eight types of water samples were obtained from the Paraho above-ground oil shale retort. These samples include three from different sampling sites on the retort, two from different sites in the oil storage facilities, and three samples from different sites at the evaporation pond. Analyses of the pH, oxidizing capacity as Eh, conductivity, alkalinity, ammonia, total sulfur, and thiosulfate are described. Also, the results of these analyses are presented for water samples prepared and stored by different methods. Special methods were developed for the conductivity analysis. The results for the total sulfur analysis are doubtful; a number of problems are still to be solved for this analysis. The water parameters that appear to be most vulnerable to handling and storage are the pH and conductivity.
Measurement of Contamination from PCB Sources
Authors: MacLeod KE , Lewis RG
Published: March 2009

When monitoring atmospheric polychlorinated biphenyl (PCB) levels, the sampling method used should depend on the type of source and the level of contamination. The different types of sampling equipment used, both low- and high-volume, are discussed briefly in connection with the types of sources monitored and the efficiency of the equipment in collecting and retaining the PCBs. The methodology employed in the extraction, cleanup, and analysis of the samples is also discussed. The actual PCB sources tested, both indoor and outdoor, are discussed at some length with respect to the source type, sampling methodology used, and PCB levels found. Particular attention is given to monitoring the cleanup of a PCB spill site.
Nitrosamine Air Sampling Using a New Artifact-Resistant Solid Sorbent System
Authors: Rounbehler DP , Reisch JW , Fine DH
Published: March 2009

A new air-sampling system, consisting of a mixture of magnesium silicate and an amine-trapping agent has been tested for the collection and concentration of airborne nitrosamines in atmospheres that also contain the precursors of these readily formed compounds. The new technique has been demonstrated to be resistant to in situ artifact formation and to quantitatively retain a variety of volatile nitrosamines. Two other solid sorbents, activated charcoal and Tenax-GC, were also compared for in situ formation of nitrosamines from added amines and air containing nitrogen oxides. The test conditions of preloaded amines and airborne nitrogen oxides were selected to simulate reported levels of these precursors in industrial atmospheres. Field data showing the reliability of the new technique in parallel studies with dilute (1 N potassium hydroxide) alkali impinger traps are also presented.
The Influence of Tooling Temperature on the Formability of Stainless Steel Sheets
Authors: Granzow WG
Published: March 2009

The effect of small changes in tooling temperature on the press-forming performance of ferritic and austenitic stainless steels is described. It is shown that draw depths can be increased and breakage eliminated by warming the die and cooling the punch components of the tooling. The largest improvement occurs in the austenitic steels, since the effect of temperature on strength (and therefore formability) is enhanced by increased control over the transformation of austenite to ferrite.

The technique is being used to prevent breakage in the automotive and appliance industries, and a brief description of three typical applications is included.
Formability of the Next Generation of High-Strength Low-Alloy Steels: The Effects of Low Temperatures and Processing Conditions
Authors: Krishnadev MR , Cutler LR , Sojka GJ , Guérette J
Published: March 2009

To meet the challenge of transporting mineral and energy resources from the Canadian North as well as the need to conserve materials and energy, many new high-strength low-alloy (HSLA) steels have been and are being developed. This paper presents the results of the effect of low-temperature environments on steels. Four Arctic HSLA steels, a dual-phase steel, three experimental HSLA weathering steels and three experimental boron-HSLA steels have been used in the study. Tension tests have been carried out from room temperature to −196°C (−321°F) to evaluate the formability parameters (mainly uniform elongation and strain hardening exponent). Instrumented impact tests have also been carried out on the dual-phase steel to study its ductility under high rates of deformation. The relevance of this study to formability practice (in situ as well as “shop”) of HSLA steels are pointed up. The areas where further work is needed are also discussed.
Nondestructive Evaluation of Damage in FP/Aluminum Composites
Authors: Ulman DA , Henneke EG
Published: March 2009

A wide variety of nondestructive evaluation (NDE) techniques was used to characterize the damage state of FP/aluminum (FP/Al) composite materials. (FP/Al is a material manufactured by Du Pont containing alumina fibers in an aluminum matrix.) The NDE techniques used in the present work were X-ray radiography, ultrasonic C-scan and pulse-echo, stiffness change, eddy current, thermography, acoustic emission and edge replication. The capabilities of these NDE methods to determine the in situ and fatigue damage in this material system were evaluated. After thorough initial nondestructive characterization, the specimens were subjected to several different mechanical test procedures. The mechanical tests were used to initiate damage and to monitor the subsequent material response. At several intermediate intervals in the damage development process, the specimens were removed from the test machine and resubjected to the same nondestructive characterization procedures. Three-point bending was the primary loading mechanism used to initiate and grow damage. To control the location of damage initiation, notches were machined into several specimens. Longitudinal cracks propagating from these notches were closely monitored and correlated to a reduction in material properties.
Durability/Life of Fiber Composites in Hygrothermomechanical Environments
Authors: Chamis CC , Sinclair JH
Published: March 2009

Statistical analysis and multiple regression were used to determine and quantify the significant hygrothermomechanical (HGTM) variables which influence the tensile durability/life (cyclic loading, fatigue) of boron-fiber/epoxy-matrix (B/E) and high-modulus-fiber/epoxy-matrix (HMS/E) composites. The use of the multiple regression analysis reduced the variables from 15, assumed initially, to 6 or less with a probability of greater than 0.999. The reduced variables were used to derive predictive models for compression and intralaminar shear durability/life of B/E and HMS/E composites assuming isoparametric fatigue behavior. The predictive models were subsequently “generalized” to predict the durability/life of graphite-fiber/resin-matrix composites. The “generalized” model is of simple form, predicts conservative values compared with measured data, and should be adequate for use in preliminary designs.
Experimental Investigations of Fiber Composite Reinforcement of Cracked Metallic Structures
Authors: Ratwani MM , Kan HP , Fitzgerald JH , Labor JD
Published: March 2009

The results of an experimental program, carried out to investigate the influence of composite repair patches on the life of cracked metallic structures, are discussed. The influence of parameters such as moisture, temperature, composite patch material, thickness, width, length, and ply orientations on the crack growth life of the repaired metallic structure has been investigated. The metallic materials selected were 7075-T6 and 2024-T3 aluminum alloys, and the composite patch materials selected were graphite/epoxy and boron/epoxy. The adhesive used was FM73. All the repaired specimens were tested under typical wing spectrum loading with a maximum stress of 270 MPa (39.2 ksi) tension and a minimum stress of 68.9 MPa (10.0 ksi) compression.

Experimental results indicate that composite patches can significantly reduce crack growth rate. Moisture conditioning of the composite patch increases the crack growth rate as compared with the dry patch. However, the improvement is still substantial over that of unreinforced cracked metal part. The width of the patch has considerable influence on the crack growth life. Wider patches give longer life. The length and thickness of the patch have no significant effect on the crack growth life if the patch length and thickness are sufficient to cause full load transfer to the patch.

Experimental data show that the stacking sequence of the composite patch—that is, putting ±45 or 0 deg plies near the crack surface—has no effect on the crack growth life of the metallic structure.
Practical Applications of Variable Rate Impact Testing of Reaction Injection Molding Urethanes
Authors: Driscoll SB
Published: March 2009

Instrumented variable rate impact testing has been found to be an effective analytical tool for identifying the important load-deflection response of reaction injection molding (RIM) materials. Molded parts of varying geometries can now be tested using many impacting probes or tups over a wide impacting rate range and temperature region. Complete load-deflection analysis allows the engineer to formulate, design, process, and assemble a product having improved, reliable functional performance.
Load-Environment Interaction Effects on Crack Growth in Landing Gear Steels
Authors: Saff CR , Rosenfeld MS
Published: March 2009

Recent research into the crack growth behavior of aircraft landing gear steels shows that combinations of aggressive chemical environment and high sustained loading can cause significant reduction in the fatigue crack growth life of 300M steel. Crack growth behaviors of 300M and HP 9-4-0.30 steels are compared for continuous salt water immersion and alternate immersion in synthetic sea water environments. An analysis approach which sums the crack growth due to cyclic loading in an inert environment is shown to accurately correlate and predict the combined effects of chemical environment and mechanical loading on crack growth. Crack growth behavior under landing gear stress spectra typical of Air Force and Navy usage is compared.
Fatigue-Life Prediction for Spotweld Using Neuber's Rule
Authors: Oh HL
Published: March 2009

Neuber's Rule, which states that the theoretical stress concentration factor is equal to the geometric mean of the actual stress and strain concentration factors, is employed to treat the inelastic behavior of material localized around the spotweld. The stress and strain concentrations estimated by the Rule are compared with published results obtained by the finite-element method. Results show that comparable accuracy of stress-strain estimation can be obtained with Neuber's Rule at a negligible cost and effort. Treating residual stress as a prestressing of the spotweld and using Neuber's Rule to estimate the corresponding stress-strain concentration, fatigue life of a spotweld under constant-amplitude cycling is predicted. The predicted life is in agreement with published results.
A Unified Creep-Plasticity Model for Halite
Authors: Krieg RD
Published: March 2009

Two national energy programs are considering caverns in geological salt (NaCl) as a storage repository. One is for the disposal of nuclear wastes and the other is for the storage of oil. Both short-time and long-time structural deformations and stresses must be predictable for these applications. At 300 K, the nominal initial temperature for both applications, the salt is at 0.28 of the melting temperature and exhibits a significant time-dependent behavior. A constitutive model has been developed that describes the behavior observed in an extensive set of triaxial creep tests. Analysis of these tests showed that a single deformation mechanism seems to be operative over the stress and temperature range of interest so that the secondary creep data can be represented by a power of the stress over the entire test range. This simple behavior allowed a new unified creep-plasticity model to be applied with some confidence. The resulting model recognizes no inherent difference between plastic and creep strains yet models the total inelastic strain reasonably well including primary and secondary creep and reverse loadings. A multiaxial formulation is applied with a back stress. A Bauschinger effect is exhibited as a consequence and is present regardless of the time scale over which the loading is applied. The model would be interpreted as kinematic hardening in the sense of classical plasticity. Comparisons are made between test data and model behavior.
Deformation Modeling in Sodium Chloride at Intermediate and Elevated Temperatures
Authors: Arieli A , Heard HC , Mukherjee AK
Published: March 2009

The flow stress dependence on temperature and strain rate of annealed, isotropic polycrystalline NaCl has been determined at temperatures of 296 to 673 K (0.28 to 0.63 TM) and strain rates of 10−1 to 10−8 s−1.

At elevated temperatures (T > ∼ 0.44 TM) and relatively low stress the Na+ diffusion-controlled climb of dislocations was found to be the rate-controlling deformation mechanism, and the experimental data could be fitted by a power-law function. In the same range of temperatures, at high stresses the deformation process was controlled by dislocation climb creep due to Cl− ion diffusion. At intermediate temperatures and low strain rates and at elevated temperatures and high strain rates the deformation was rate-controlled by the lattice resistance to the dislocation glide motion (Peierls mechanism).

The constitutive equations for each deformation mechanism as well as that for the transition from one deformation mechanism to another were developed in terms of strain rate, temperature, and stress. The implications of the transition from one deformation mechanism to another over a wide range of temperatures on the deformation modeling for this material are discussed. The application of such analysis to understand and predict the rheological behavior of halite aggregates in nature in buried salt deposits is considered.
Brittle Behavior of a Varved Clay During Triaxial Undrained Shear Strength Tests
Authors: Bemben SM
Published: March 2009

The brittle behavior aspects of the undrained shear strength of a varved clay deposited in a glacial-era lake are presented. The cause of the brittle behavior is surmised to be calcareous in nature. The calcareous material is an integral part of the natural soil structure. The influences of rate of strain, relative level of consolidation stress during shear in comparison with the consolidation stress, specimen quality, and mode of loading are illustrated by diagrams of shear strength versus mean effective stress (q-p) paths. The undrained shear strength to consolidation stress (c/p) ratio varies systematically. The brittle behavior is less prominent during laboratory shear strength testing, when the soil's natural structure is disturbed. The correlation of laboratory-measured undrained shear strength with field-measured vane shear strength values is presented.