bluuebunny/crossref_metadata_2025 huggingface dataset:
Afghanistan: A Legacy of Violence? Internal and External Factors of the Enduring Violent Conflict
Authors: Mishali-Ram Meirav
Published: December 2008

Afghanistan has been the scene of enduring violent conflict for three decades, yet the sources of its conflict date back to the establishment of the Afghan state in the eighteenth century. The American-led military intervention in October 2001 ended the extremist Taliban rule in the torn country and facilitated democratic elections but did not terminate the Afghan turmoil and the threat of its regional spillover effects. Six years after the invasion, hopes for renovation, peace, and stability are entwined with great challenges and fears of continuing insecurity. Alongside efforts to advance social, economic, and security reforms, the Afghan government, assisted by international forces, faces escalating insurgency by Taliban and al-Qaeda militants. This complex and dangerous situation questions the possibility of imminent peace and stable democracy in a country where violence and enduring conflict have been instrumental throughout its history.

The central thesis of this essay is that to understand the Afghan conflict we must take into account a variety of interrelated factors from the global, regional, and internal cycles of analysis, none of which can be isolated or seen as satisfactory in itself. More specifically, it is contended here that efforts made by external powers to manage ethnic conflicts and establish a nation-building process in foreign countries should be based on broad consent of the parties involved.
Where Will I Dwell? A Sociology of Literary Identity within the Iranian Diaspora
Authors: Vahabzadeh Peyman
Published: December 2008

By offering a comprehensive survey of the theories pertaining to the literature produced by Iranian expatriate communities, this essay argues that the many faces of “emigration literature” indeed reflect the immigrants' varied experiences of their departure and their host societies. Furthermore, the essay pursues the points of divergence of this genus of literature to show how, ironically, various strands and different works in Iranian emigration literature contribute to the diversity of literature in their host societies. This “dual function” characterizes emigration literature: on the one hand, as a literature of departure from a homeland that vanishes in memory, this strand of literature narrates the existential dilemmas of the loss of a past in one's homeland; on the other hand, the existential settlement in the host land drifts such narrative into an ever-expanding future not necessarily bound by a place. Emigration literature dwells in this terra nulleum.
Martyrdom and the “Good Life” In the Iranian Cinema of Sacred Defense
Authors: Partovi Pedram
Published: December 2008

This essay investigates the place of cinema in the formulation and maintenance of an Iranian popular civil religion—reworking older ideas and practices largely taken from Islam to articulate with modern social and political change in Iran. Of particular interest is the theme of martyrdom in the Iranian cinema of sacred defense, originally conceived to depict the spiritual dimensions of the Iran-Iraq war (1980-88). I explore the foundational role of this genre in the postrevolutionary Iranian cinema and its development in concert with television. I then argue that representations of martyrdom in the Cinema of Sacred Defense, born of a complex history, are attempts to make the divine manifest in film and in real life. While the Cinema of Sacred Defense is often claimed to be a marked departure from previous Iranian films, some of its preoccupations remain much in line with the now-banned popular commercial cinema of the Pahlavi era, often referred to as filmfarsi (Persian film). The film chosen as the case study, Layli ba man ast (Leily Is with Me; Kamal Tabrizi, 1996), is of particular interest not only because it is among the most popular releases of the Sacred Defense genre but also because it is a parody of the genre. The film also provides an incisive critique of new forms of social organization, social aspirations, and personal success (the “good life”) that the revolution and the war engendered. Finally, I turn to how Leily Is with Me and other popular titles of the past decade may indicate the reconstitution of the much-maligned filmfarsi genre.
Overexpression of Pygopus2 protects HeLa cells from vinblastine-induced apoptosis
Authors: De Degejing , Chen Apeng , Wu Zhiqiang , Lv Songya , He Guoqing , Qi Yipeng
Published: November 2008

Pygopus, a very important component of the Wnt signaling transcriptional complex, has multiple functions in both Wnt-dependent and -independent pathways. Human Pygopus2 (Pygo2) is expressed in many cancers and plays an important role in tumor growth. In the present study, we generated human carcinoma (HeLa) cell lines stably expressing Pygo2, which counteracts vinblastine-induced apoptosis. The anti-apoptotic function was determined by DNA fragmentation, sub-G1 appearance, loss of mitochondrial membrane potential (Δψm) and the activation of caspase-9 and caspase-3. In addition, we found that Pygo2 effectively blocks vinblastine-induced c-Jun and AP-1 activation, maintains the anti-apoptotic protein Bcl-2 in an unphosphorylated state, and thus can render cells resistant to apoptosis. However, Pygo2 does not alter the vinblastine-induced cell cycle changes. Here, we describe an anti-apoptotic activity exerted by Pygo2 through blocking activation of the JNK/AP-1 signaling pathway induced by vinblastine.
Functional genetic mouse models: promising tools for investigation of the proteolytic internet
Authors: Krüger Achim
Published: November 2008

Knockout mice are the gold standard to probe for the role of a specific protease within the interacting network of proteases, substrates, and inhibitors. This proteolytic network, or protease web, determines cell signaling and organ homeostasis. Therefore, protease deficiency or inhibition is intrinsically tied to alterations within this network, always leading to new molecular phenotypes, which define susceptibility of an organ to disease. Furthermore, recent hints, mainly from research on matrix metalloproteinases, about the impact of the protease web on inter-organ signaling molecules suggest the existence of a proteolytic internet of communicating local organ- or molecular polymorphism-specific networks, thereby defining homeostasis and disease susceptibility in the whole organism.
Mercury and cadmium trigger expression of the copper importer Ctr1B, which enables Drosophila to thrive on heavy metal-loaded food
Authors: Balamurugan Kuppusamy , Hua Haiqing , Georgiev Oleg , Schaffner Walter
Published: November 2008

Organisms from insects to mammals respond to heavy metal load (copper, zinc, cadmium, and mercury) by activating the metal-responsive transcription factor 1 (MTF-1). MTF-1 binds to short DNA sequence motifs, termed metal response elements, and boosts transcription of a number of genes, notably those for metallothioneins. In Drosophila, MTF-1 somewhat counter-intuitively also activates transcription of a copper importer gene (Ctr1B) in response to copper starvation. Here, we report that mutant flies lacking Ctr1B are extremely sensitive to cadmium and mercury treatment, but can be rescued by excess copper in the food. We thus propose that copper, by competing for binding sites on cellular proteins, alleviates the toxic effects of mercury and cadmium. Such a scenario also explains a seemingly fortuitous metal response, namely, that cadmium and mercury strongly induce the expression of a Ctr1B reporter gene. Thus, the transcription enhancer/promoter region of the Ctr1B copper importer gene is subject to three modes of regulation. All of them depend on MTF-1 and all make biological sense, namely, (i) induction by copper starvation, (ii) repression by copper abundance, and (iii), as shown here, induction by cadmium or mercury at normal copper supply.
Aptamers selected against the unglycosylated EGFRvIII ectodomain and delivered intracellularly reduce membrane-bound EGFRvIII and induce apoptosis
Authors: Liu Yingmiao , Kuan Chien-Tsun , Mi Jing , Zhang Xiuwu , Clary Bryan M. , Bigner Darell D. , Sullenger Bruce A.
Published: November 2008

Epidermal growth factor receptor variant III (EGFRvIII) is a glycoprotein uniquely expressed in glioblastoma, but not in normal brain tissues. To develop targeted therapies for brain tumors, we selected RNA aptamers against the histidine-tagged EGFRvIII ectodomain, using an Escherichia coli system for protein expression and purification. Representative aptamer E21 has a dissociation constant (K
d) of 33×10-9 m, and exhibits high affinity and specificity for EGFRvIII in ELISA and surface plasmon resonance assays. However, selected aptamers cannot bind the same protein expressed from eukaryotic cells because glycosylation, a post-translational modification present only in eukaryotic systems, significantly alters the structure of the target protein. By transfecting EGFRvIII aptamers into cells, we find that membrane-bound, glycosylated EGFRvIII is reduced and the percentage of cells undergoing apoptosis is increased. We postulate that transfected aptamers can interact with newly synthesized EGFRvIII, disrupt proper glycosylation, and reduce the amount of mature EGFRvIII reaching the cell surface. Our work establishes the feasibility of disrupting protein post-translational modifications in situ with aptamers. This finding is useful for elucidating the function of proteins of interest with various modifications, as well as dissecting signal transduction pathways.
Factors That Affect the Precision of Mechanical Tests
Authors: Papirno R , Weiss HC
Published: December 2008

Description

Seventeen papers describe investigations where the precision of test procedures were either examined or enhanced. Topics include hardness testing, fatigue and fracture testing, and specimen alignment and gripping problems.
Distal Locking for Unstable Femoral Fractures: Is It Necessary? A Preliminary Report
Authors: Behrens F , Johnson J
Published: December 2008

This is a preliminary report of a randomized-surgeon trial. This trial was carried out to determine if nail impaction into the distal femoral metaphysis (IMP) was as effective as distal locking (LOC) in preventing shortening and malalignments in unstable femoral fractures. Fourteen fractures were treated with IMP and 30 with LOC. The two groups had similar demographic, injury, and treatment characteristics and did not significantly differ in healing times, shortening, and rotational or angulatory deformities. There was a slight increase in complications in the LOC group. We concluded that distal nail impaction is an attractive alternative to distal locking with screws or deployable wings. It appears to be safer and has a lower complication rate.
Advances in Thermoplastic Matrix Composite Materials
Authors: Newaz GM
Published: December 2008

Description

Advances in Thermoplastic Matrix Composites Materials Provides an overview of recent accomplishments in advanced aerospace thermoplastic composites. 18 pages cover these important issues:

• Processing

• Thermal and Mechanical Behavior

• Delamination
Vertebrate Pest Control and Management Materials: Sixth Volume
Authors: Fagerstone KA , Curnow RD
Published: December 2008

Description

9 papers cover animal damage control techniques and research methodology, with emphasis on vertebrate pest control and assessment methods for control techniques. For wildlife biologists, pest control operators, and university researchers interested in animal damage control.
Sorption Isotherms: A Catalog and a Data Base
Authors: Hansen KK
Published: December 2008

In the catalog, sorption isotherms are plotted for more than 100 materials. Measured sorption values from different sources are put into a data base, and for each set of values the best curve through desorption and adsorption measuring points are fitted using the extended Posnow equation. A page of the catalog shows both data values and a figure with data points and approximated curves. An IBM PC has been used to build up the data base that is stored on a diskette marked SORPTION. The necessary data input and plotting programs for the data base as well as programs for curve fitting of data points are also stored on the diskette. The programs have been discussed in a separate report where the execution of the programs is also described.
Water Vapor Transmission and Moisture Accumulation in Polyurethane and Polyisocyanurate Foams
Authors: Schwartz NV , Bomberg M , Kumaran MK
Published: December 2008

Water vapor transport through rigid polyurethane and polyisocyanurate foams was investigated using three test methods—two under isothermal conditions and one in the presence of a thermal gradient. All three methods yielded water vapor transmission coefficients of the materials. It is observed that the magnitude of the coefficients increases rapidly with temperature above 20°C. In one of the isothermal methods called a modified cup method, developed at the Institute for Research in Construction, only the temperature has to be controlled and this is considered a definite advantage over the other method, ASTM Test Methods of Water Vapor Transmission of Materials, (E 96-80) dry cup method, in which both temperature and relative humidity are to be controlled. Further, the modified cup method also allows the determination of moisture accumulated in the test specimen during moisture transport. It was conclusively shown that during isothermal transport processes no moisture accumulates in either the polyurethane or the polyisocyanurate specimens.

The accumulation and distribution of moisture in the presence of a thermal gradient was also investigated. Contrary to the isothermal process, the moisture transport in the presence of a thermal gradient acting in the same direction as the vapor pressure gradient results in the accumulation of large quantities of water in the foams. This phenomenon may be partly attributed to the temperature dependence of the water vapor transmission coefficients.
Pressurized Flammability Limits of Metals
Authors: Zabrenski JS , Werley BL , Slusser JW
Published: December 2008

The combustion of seventeen metals was studied using a pressurized oxygen index apparatus. The procedure measures the metal's flammability limits (minimum concentration or minimum pressure that enables equilibrium combustion). Metals tested included 201, 304, and 430 stainless steels, copper, brass 360, Monel® 400, carbon steel, 9% nickel steel, Incoloy® 800, Inconel® 600, Stellite® 6, and to a lesser extent, 316 and 410 stainless steels, zinc, titanium, and Ti-6A1-4V. Vertical rods 6.4-mm (0.25-in.) in diameter were principally studied, although some 3.18-mm (0.125-in.) rods and 6.4-mm (0.25-in.) diameter, 0.89-mm (0.035-in.) wall tubes were also tested. Tests of 304 rods were also conducted with specimens at up to 90° to the vertical to assess the effect of melt drainage patterns. In all cases, the tests explored upward propagation against a small downward gas flow at gage pressures to 10.34 MPa (1500 psig).

Metals were ranked in the following order of lowest to highest compatibility: aluminum, carbon steel, 9% nickel steel, 10.5% aluminum bronze, zinc, 201, 304, 430, and Incoloy® 800, which exhibited propagations at pressures below the 10.34 MPa (1500 psig) limit of the apparatus. Stellite® 6, brass 360, Inconel® 600, copper, and Monel® 400 all resisted propagation at the maximum gage pressure of 10.34 MPa (1500 psig).

Stainless steel 304 rods exhibited much greater thresholds than did tubes; whereas carbon steel rods and tubes produced more nearly equal thresholds. Alloy 304 also exhibited much lower thresholds after annealing and exhibited the lowest threshold with a vertical orientation. An approach to using these and other data to support increased usage of 304 is reviewed.
In Vitro Corrosion of Porous Alloys
Authors: Lucas LC , Lemons JE , Lee J , Dale P
Published: December 2008

Porous metallic surfaces are currently being applied to both orthopedic and dental implant devices. The increased surface areas provided by these systems have caused many in the health sciences to be concerned over an accelerated release of corrosion products into the adjacent and systemic tissues. The objective of this study was to evaluate the corrosion characteristics of six available porous alloy systems by utilizing electrochemical corrosion analyses. The surface area provided by the selected porous structures increased 1.2 to 7.2 times over that of the solid forms of the alloys. The corrosion rate for the porous alloys was in a range of 1.2 to 5.2 times greater than that for the solid alloys. In general, the increase in corrosion rate at the corrosion potential was not of the same magnitude as the increase in surface area. At potentials greater than the corrosion potential, the corrosion rates for the porous alloys were normally greater than the rates experienced by the solid alloys. In conclusion, the porous alloy systems investigated demonstrated increased corrosion magnitudes. Since the long-term effects of the released metallic constituents have not been evaluated at this time, surface treatments aimed at reducing the corrosion rates should continue to be evaluated.
Fracture Surfaces of Irradiated Composites
Authors: Milkovich SM , Sykes GF , Herakovich CT
Published: December 2008

Electron microscopy was used to analyze the fracture surfaces of T300/934 graphite/epoxy, unidirectional, off-axis tensile coupons which were subjected to 1.0 MeV electron radiation at a rate of 5.0 × 107 rad/h for a total dose of 1.0 × 1010 rad. Fracture surfaces from irradiated and nonirradiated specimens tested at 116 K (−250°F), room temperature, and 394 K (+250°F) were analyzed to assess the influence of radiation and temperature on the mode of failure and variations in constituent material as a function of environmental exposure. Micrographs of fracture surfaces indicate that irradiated specimens are more brittle than nonirradiated specimens at low temperatures. However, at elevated temperatures the irradiated specimens exhibit significantly more plasticity than nonirradiated specimens. The increased plasticity in irradiated specimens tested at elevated temperature is much more evident in 10° offaxis specimens. This is the result of the high shear stresses in these specimens. The same high degree of plasticity is not observed in the 90° specimens which fail at a much lower ultimate strain. Little difference in fracture surfaces and material behavior for irradiated and nonirradiated specimens is noted for room temperature specimens. The analysis of the photomicrographs is shown to correspond well with mechanical behavior of the specimen.
Principles of Calibration
Authors: Taylor JK
Published: December 2008

Measurement consists of comparison of samples of unknown composition with standards of known composition or with scales calibrated with respect to such standards. The standards used must simulate the unknowns with respect to matrix and level of analyte if the comparisons are to be valid. This paper reviews the fundamental aspects of calibration, describes various approaches that may be utilized, and considers the sources of error in the calibration process. The evaluation of calibration uncertainty and ways to minimize it are discussed. A general discussion of linear relationships as applied to calibration is presented.
Microstructural Effects on the Irradiation Growth of Zr-2.5Nb
Authors: Parker JD , Perovic V , Leger M , Fleck RG
Published: December 2008

Irradiation growth tests at 553 K and a fast (E > 1.6 × 10−13 J) neutron flux of about 6.5 × 1017 n m−2s−1 were performed on specimens of Zr-2.5Nb pressure tubes to a neutron fluence of 3.5 × 1025 n m−2. The tubes were produced by different routes designed to change texture, grain shape, and dislocation density, but X-ray diffraction studies showed only minor changes in texture and dislocation density. However, electron microscopy revealed marked differences in dislocation substructure and second-phase distribution.

All transverse specimens exhibited similar negative growth behavior. However, the longitudinal specimens showed different growth characteristics. Generally a three-stage growth curve was observed showing an initial offset, a low growth rate regime, and a region of apparent steady-state growth. This behavior does not fit with the normal texture, grain shape, and dislocation density dependencies which have previously been reported. An explanation is presented based on partitioning of irradiation-induced point defects, with interstitials attracted to -type dislocations or second-phase boundaries and vacancies migrating to both grain and sub-grain boundaries.
Light Scattering Characteristics of Some Metal Surfaces—A Smoothing Effect?
Authors: McNeil JR , Wei LJ , Casstevens J , Herrmann WC , Stover JC
Published: December 2008

Angularly resolved light scattering measurements of several materials are discussed. Root mean square values of surface roughness, slope and total integrated scatter are calculated. Results are compared to measurements made using a noncontact, optical profilometer. Samples of polished and diamond turned Cu, Si, Mo and electroless Ni are examined. Some surfaces show a change in angular scatter characteristic upon deposition of films using ion beam and magnetron sputtering; scattering is changed to become more in the specular direction. In some cases, total integrated scatter is reduced up to a factor of four, and surface microroughness at high spatial frequencies is reduced by a factor of ten.
Alumina/Silica Multilayer Coatings for Excimer Lasers
Authors: Foltyn SR , Jolin LJ
Published: December 2008

The coating parameter that most strongly influences optical damage resistance is the choice of materials used to produce a component. During the course of testing of hundreds of ultraviolet reflectors involving 12 different material combinations, multilayer stacks of Al2O3/SiO2 have demonstrated a superior ability to resist laser-induced damage. Further, damage thresholds for these coatings are at least twice as high as for reflectors composed of other materials: In particular, thresholds of 6 J/cm2 at 248 nm (15 ns) and 12 J/cm2 at 351 nm (12 ns) have been measured. Comparative results are presented for a variety of materials at both wavelengths as are preliminary results for alumina-based antireflective coatings.
Constant-Amplitude Fatigue Behavior of Five Carbon or Low-Alloy Cast Steels at Room Temperature and −45°C
Authors: Stephens RI , Chung JH , Lee SG , Lee HW , Fatemi A , Vacas-Oleas C
Published: December 2008

Five common carbon or low-alloy cast steels—SAE 0030, SAE 0050A, C-Mn, Mn-Mo and AISI 8630—were subjected to constant-amplitude fatigue tests at room temperature and at the common low climatic temperature of −45°C (−50°F). Tests included smooth specimen axial low and high cycle fatigue and compact type (CT) specimen crack growth behavior from 10−5 n/cycle (4 × 10−4 in./cycle) to threshold values at 10−10 m/cycle (4 × 10−9 in./cycle). Three of the five steels had nil ductility transition temperatures above the low test temperature. Despite this, all five cast steels showed equivalent or better fatigue resistance at the low temperature, except for some very short life low-cycle fatigue tests and for some very high fatigue crack growth rates where fracture was imminent. Scanning electron fractographic analysis indicated that ductile type fatigue crack growth mechanisms with or without striations occurred for all steels at both test temperatures except for a few interdispersed cleavage facets in 0050A steel at very high crack growth rates. At the low temperature, monotonic and cyclic stress-strain properties Su, Sy, and Sy' increased by an average of about 10%, fatigue limits increased from 2 to 25%, and ΔKth increased from 0 to 90%. No consistent correlations existed between fatigue and monotonic properties at either temperature. Mean stress effects at near ΔKth levels appeared to be influenced by crack closure.
Indentation of Brittle Materials
Authors: Marshall DB , Lawn BR
Published: December 2008

The use of indentation testing as a method for investigating the deformation and fracture properties of intrinsically brittle materials, glasses, and ceramics is examined. It is argued that the traditional plasticity models of hardness phenomena can be deficient in some important respects, notably in the underlying assumptions of homogeneity and volume conservation. The penetrating indenter is accommodated by an intermittent “shear faulting” mode, plus (to a greater or lesser extent, depending on the material) some structural compaction or expansion. These faults provide the sources for initiation of the indentation cracks. Once generated, the cracks can grow under the action of subsequent external tensile stresses, thereby taking the specimen to failure.

In this presentation the mechanical basis for describing these phenomena will be out-lined, with particular emphasis on the interrelations between hardness and other characteristic material parameters, such as elastic modulus and fracture toughness. Procedures for quantitative determination of these parameters will be discussed. Extension of the procedures to the measurement of surface residual stresses in brittle materials will be made to illustrate the power of the indentation method as an analytical tool for materials evaluation.
Recent Developments in Test Methods for Investigating Crevice Corrosion
Authors: Kain RM , Lee TS
Published: December 2008

The ultimate successful utilization of stainless steels and related alloys in marine and other chloride containing environments will depend on a more complete understanding of the factors affecting crevice corrosion. To this end, numerous test methods have been devised to investigate the effects of various metallurgical and environmental parameters. While not totally ignored in past research, more recent investigations have also emphasized the importance of crevice geometry considerations. For example, mathematical modelling of chemistry changes in the crevice electrolyte indicates a strong dependency on crevice gap and crevice depth dimensions. In addition, the bulk environment chloride level will affect the ultimate crevice electrolyte pH and chloride level. Accordingly, a given stainless steel may encounter a range of crevice solutions of varying pH and chloride level dependent upon the crevice geometry and bulk environment conditions encountered.

Two experimental approaches for studying crevice corrosion are presented. A remote crevice assembly and a compartmentalized cell have been used to study both the initiation and propagation phases of crevice corrosion. Both methods make use of two specimen components consisting of physically separated but electrically connected anodes (crevice portion) and cathode members. Accordingly, corrosion potential and current data along with conventional mass loss and penetration data can be gathered. A significant feature of these methods is that neither requires the application of current from an external source. Both initiation and propagation of crevice corrosion occur spontaneously. The two techniques differ slightly in that the remote crevice assembly requires creation of a physical crevice on the anode while the compartmentalized cell approach uses a nonoccluded anode in a simulated crevice electrolyte. With the compartmentalized cell, crevice electrolytes are simulated based on the predictions of a mathematical model of crevice corrosion.

Results from recent tests investigating the effects of variations in crevice tightness, bulk solution composition, and crevice solution pH are described in the present article. Remote crevice assembly research has focused on efforts to provide a consistent and reproducible condition of crevice tightness on the anode. The compartmentalized cell research has dealt with the effects of changes in both bulk environment conditions and crevice solution pH. Insights gained on the relative influence of these various factors on crevice corrosion lend credence to the testing concepts embodied by both the remote crevice assembly and the compartmentalized cell.
Evaluating the Suitability of the NACE Standard Test, TM-01-77, for Testing 13% Chromium Martensitic Stainless Steels for Sulfide Stress Cracking Resistance
Authors: Whitehead TD , Baloun CH
Published: December 2008

Potentiostatic anodic polarization curves were used to study the pitting resistance of American Iron and Steel Institute (AISI) Type 420 (Unified Numbering System [UNS] S42000) stainless steel in solutions containing bicarbonate, sodium chloride, hydrogen sulfide, and carbon dioxide. The effect of applied potential on the sulfide stress cracking (SSC) of this material was also investigated. The appropriateness of the test solution, described in the National Association of Corrosion Engineers (NACE) (TM-01-77), for determining the SSC of Type 420 stainless steel is then evaluated in light of the results of this investigation.
A Study of Defect Structures in Fast Neutron Irradiated Nickel and Iron by Measurements of Magnetic Anisotropy
Authors: Maeta H , Ono F
Published: December 2008

Measurements of the magnetic anisotropy in pure nickel and bcc iron after fast neutron irradiation at 5 K and after successive isochronal anneals at various temperatures between 5 and 320 K were carried out at 4.2 and 77 K for nickel and iron, respectively. The existences of 110-dumbbell-type interstitial configurations in iron and 100-dumbbell-type in nickel have been confirmed. By analyzing the intensity data after isochronal anneals, we found that the clusters of 100-dumbbell interstitials on the (100) planes in nickel transfer onto (111) planes after a 320 K anneal and grow into Frank-type dislocation loops. For iron they are initially aggregated on (110) planes and slip onto (111) planes after a 220 K anneal. Comparing the results of magnetic anisotropy in iron with those in nickel, we have also explained the high migration temperature of interstitials in bcc iron by considering the ferromagnetic condition of the 3d-up and 3d-down spin subbands.
Flexible Manufacturing Systems: The MODIAC Project
Authors: Bruno G , Demartini C , Rivoira S , Valenzano A
Published: December 2008

Flexible manufacturing systems consist of an heterogeneous collection of different devices such as machine tools, programmable logic units, robots, and computers. The efficient organization of the system depends on the integration level of these different elements. This paper discusses the use of MODIAC (Modular Integrated System for Automation and Process Control), the Local Area Network developed within the Computer Science Project sponsored by the Italian National Research Council, as an efficient solution for implementing a computer-integrated manufacturing cell. Advanced communication methodologies that rely on Local Area Network Technology as the interconnection structure for the cell components are also discussed.
J-RCurve Determination Using Precracked Charpy Specimens and the Load-Drop Method for Crack Growth Measurements
Authors: Kapp JA
Published: December 2008

J-R curves for two aluminum alloys, a titanium alloy, and a high strength, low alloy steel at two different strength levels were determined using precracked Charpy specimens. Three methods were used to measure crack growth: (1) multi-specimen, (2) compliance unloading, and (3) the “load-drop” method. The “load-drop” method assumes that crack growth occurs only after peak load has been attained and the amount which the load decreases after peak load is related to the size of the uncracked ligament. Comparisons between the three methods for all the materials show remarkably similar J-R curves. Also, using these curves to determine a JIc indicates very little difference between the “load-drop” method and the others in the measurement of toughness.
High-Temperature Oxidation of Zircaloy in Hydrogen-Steam Mixtures
Authors: Chung HM , Thomas GR
Published: December 2008

Oxidation rates of Zircaloy-4 cladding tubes have been measured in hydrogen-steam mixtures at 1200 to 1700°C. For a given isothermal oxidation temperature, the oxide layer thicknesses have been measured as a function of time, steam supply rate, and hydrogen overpressure. The oxidation rates in the mixtures were compared with similar data obtained in pure steam and helium-steam environments under otherwise identical conditions. The rates in pure steam and helium-steam mixtures were equivalent and comparable to the parabolic rates obtained under steam-saturated conditions and reported in the literature. However, when the helium was replaced with hydrogen of equivalent partial pressure, a significantly smaller oxidation rate was observed. For high steam supply rates, the oxidation kinetics in a hydrogen-steam mixture were parabolic, but the rate was smaller than for pure steam or helium-steam mixtures. Under otherwise identical conditions, the ratio of the parabolic rate for hydrogen-steam to that for pure steam decreased with increasing temperature and decreasing steam supply rate. The smaller parabolic rates in the hydrogen-steam mixtures indicate that, under the test conditions, a considerable amount of hydrogen was dissolved in Zircaloy during oxidation and, as a consequence, oxygen transport in both the oxide and alpha-phases was slower than in the corresponding phases produced in pure steam or helium-steam mixtures. The findings are discussed in relation to some reported high-temperature transport characteristics of oxygen ions in the oxide formed in hydrogen-steam mixtures. For smaller steam supply rates (sufficiently small but still larger than the “steam starvation” limit), significantly smaller linear oxidation rates were observed in the hydrogen-steam mixture, which indicates that the oxidation rate was limited either by the gaseous transport of the steam molecules or as a result of chemical reaction between the chemisorbed oxygen on the zirconium oxide surface and the gaseous hydrogen molecules. This phenomenon of “hydrogen blanketing” is discussed in relation to fuel rod heatup in a degraded-core-accident situation.
Measurement of Stable Crack Growth Including Detection of Initiation of Growth Using the DC Potential Drop and the Partial Unloading Methods
Authors: Schwalbe K-H , Hellmann D , Heerens J , Knaack J , Müller-Roos J
Published: December 2008

The ability of the DC potential drop method and the partial unloading technique to measure crack growth and to detect initiation of crack growth has been investigated using a number of steels and aluminum alloys. It was found that within the range of parameters investigated both of these methods can be recommended for the determination of the R curve; however, since at small amounts of crack growth, the DC potential drop method gave more consistent results, it is therefore considered to be superior. The initiation values Jo of the J integral determined by fractography were compared with JIc as obtained by current practice. It was found that ductile fracture toughness JIc is poorly related to initiation or to a specific amount of crack growth. A modification of the JIc procedure is proposed.

Two contacting arrangements of the DC potential drop method were checked for initiation detection: one indicates initiation by a potential minimum (related to a J value Jmin), the other by the intersection of the R curve with the blunting line (related to a J value Jint).
The Use of Small-Format Aerial Photography in Aquatic Macrophyton Sampling
Authors: Breedlove BW , Dennis WM
Published: December 2008

Standard 35- and 70-mm low altitude aerial photography provides a low cost, effective means for sampling aquatic macrophyte communities. Both color and color infrared (CIR) film have been used successfully. A haze filter should be used with color film, and a Wratten® 12 or 15 filter should be used with color infrared. Adequate water penetration is provided by color film in waters with high turbidity and suspended matter while CIR film may be preferable in low turbidity waters. Ground coverage tables provide scale and areal coverage in tabular form at various altitudes, focal lengths, and appropriate time intervals to ensure 60% stereo overlap. Various cameras and lens combinations can be used; however, a 28-mm lens with the 35-mm single-lens reflex (SLR) camera and a 40- or 80-mm lens with a 70-mm camera have proven very effective and allow maximum areal coverage at lower altitudes. This flexibility allows photo missions to be flown below cloud bases in less than optimum conditions while still obtaining good quality photography.

When combined with appropriate ground surveys and knowledgeable photointerpretation, small-format photography can provide detailed documentation of the areal extent of macrophyte communities and, in many instances, of species composition as well.
Fire Performance of Reinforced Concrete Columns
Authors: Lie TT , Lin TD
Published: December 2008

To develop general methods for the prediction of the fire resistance of reinforced concrete columns, experimental and theoretical studies were carried out. Results obtained in the first phase of the study, which involved the testing of twelve columns, are given. Of the variables studied in this phase, load, cross-section size, and type of aggregate had the largest influence on the fire resistance of the columns. The influence of concrete moisture content was, within the range studied, insignificant. Column temperatures, deformations, and fire resistance, calculated using a mathematical model, were in good agreement with those measured. The variables that will be studied in a second phase study are outlined.
Mode I Fatigue Crack Growth Under Biaxial Stress at Room and Elevated Temperature
Authors: Brown MW , Miller KJ
Published: December 2008

Fatigue crack growth rates have been measured in different biaxial stress fields for a variety of stress ranges at two temperatures. It is shown that a negative T-stress accelerates the crack propagation, the increase in growth rate being greater for high stresses. Different methods of determining plastic zone size are compared, and a crack growth correlation with crack-tip plasticity is proposed for remote loads not greater than the yield stress.
Short-Cut Chronic Toxicity Estimates Using Daphnia magna
Authors: Adams WJ , Heidolph BB
Published: December 2008

The use of a partial life cycle test together with an application factor (AF) is a reliable way to estimate the traditional Daphnia magna 21-day GM-MATC. Application factors were determined for twelve different endpoints from 20 D. magna 21-day chronic tests by dividing the respective endpoints by the 21-day GM-MATC for each chemical. The data indicate that the 48-h no-effect concentration, the 7-, 14-, and 21-day EC50 values, and the 7- and 14-day geometric mean no-effect/effect concentrations can be used with small AFs to reliably estimate the 21-day GM-MATC. The respective AFs are 2.9, 6.0, 2.0, 4.2, and 2.7.

The cost associated with obtaining an estimate of the 21-day GM-MATC from a 2-, 7-, 14-, or 21-day study is $800, $5000, $10 000, and $15 000, respectively. The 48-h no-effect concentration provides the shortest and most effective test and does so without sacrificing accuracy.

For purposes of ranking chemicals and obtaining preliminary estimates of environmental safety margins, the use of a 48-h no-effect concentration from an acute toxicity test and an AF (33) is recommended as a cost effective way to estimate the chronic geometric mean maximum acceptable toxicant concentration (GM-MATC) for D. magna.

The results of this study indicate that there are only minor differences between 14- and 21-day GM-MATCs. Therefore we recommend that standard protocols for testing D. magna be changed to require only a 14-day period of exposure instead of 21 days. The results of this study also provide evidence that a chronic test as short as 7 days could be conducted without significant loss of accuracy.
Delamination Threshold and Loading Effect in Fiber Glass Epoxy Composite
Authors: Bathias C , Laksimi A
Published: December 2008

Helicopter rotor heads made of glass fiber-epoxy composite show good strength, particularly in fatigue failures. However, interlaminar defects may always grow under the effect of loading in bending. To predict the development of these plane defects, the delamination threshold and low crack growth rate were studied in double cantilever beam type specimens calibrated by compliance. Experimentally, a delamination threshold exists below which a plane crack does not propagate, either in Mode I or Mode II testing. Fatigue loading may cause the growth of delamination between adjacent plies at a strain energy release rate ΔGth five times lower than the fracture energy Gc. This difference is relatively insignificant by comparison with metals since in numerous alloys the difference can be as high as 100. This demonstrates the importance of determining a delamination threshold to evaluate the damage tolerance of the composite.

Complex loadings were introduced into our tests by programming tempory overloads and sequences of loading at two stress levels during cycling. The glass fiber-epoxy composites do not show significant memory effect, but are sensitive to the load ratio R.
Placement and Compaction of Asphalt Mixtures
Authors: Wagner FT
Published: December 2008

Description

Examines the effect of low mixing and compaction temperature on engineering properties of asphalt pavement; low density resulting from insufficient rolling equipment and improper construction procedures; asphalt concrete density measurements; procedures for estimating the service life of pavement when materials do not conform to specifications; and the value of creep tests in determining an asphalt mixture’s ability to resist traffic densification.
Damage Tolerance of Metallic Structures: Analysis Methods and Applications
Authors: Chang JB , Rudd JL
Published: December 2008

Description

Discusses damage tolerance design requirements, analysis procedures, and their application to primary structures made of conventional metallic materials.
Refractory Metals and Their Industrial Applications
Authors: Smallwood RE
Published: December 2008

Description

STP 849 provides a comprehensive description, including their properties and uses, of molybdenum, niobium, tantalum, and tungsten. Includes discussion of electrical, electronic, and corrosion-resistant applications at ambient temperatures.
Measurement of Rock Properties at Elevated Pressures and Temperatures
Authors: Pincus HJ , Hoskins ER
Published: December 2008

Description

Summarizes the state of this experimental art and documents new testing techniques. Focuses on permeability, pore and bulk compressibility, deformation, rock salt creep and deformation, dynamic properties, thermal conductivity and expansion, and thermo mechanical and transport properties.
Masonry: Research, Application, and Problems
Authors: Grogan JC , Conway JT
Published: December 2008

Description

Provides never before published information on test methods, field applications, and field problems in masonry, as well as current research on masonry assemblages.
Thermal Insulation: Materials and Systems
Authors: Powell FJ , Matthews SL
Published: December 2008

Description

STP 922 is intended to cover both industrial and residential types of thermal insulation. This collection of 47 papers imparts technical information on
Postoperative mortality in parathyroid surgery in Sweden during five decades: improved outcome despite older patients
Authors: Norenstedt S , Ekbom A , Brandt L , Zedenius J , Nilsson I-L
Published: November 2008

Objective

Primary hyperparathyroidism (pHPT) is a common endocrine disorder. In Europe, pHPT has been associated with premature death in cardiovascular disorders. Our question was whether the risk of postoperative death has been affected by the increased proportion of elderly patients referred for parathyroid surgery.

Methods

The nationwide Cancer Registry and Causes-of-Death Registry were used to analyze mortality among 14 635 Swedish patients subjected to parathyroid adenomectomy (PTx) during 1961–2004. Standard mortality ratios (SMR) and the 95% confidence intervals (CI) were calculated with the entire Swedish population as control, standardized for age, gender and calendar year.

Results

The observation period was more than 166 000 person-years. The overall perioperative (30-day) mortality rate was 1.3% (185/14 635; SMR 7.9; CI 6.82–9.15); 1.1% for women (132/11 500; SMR 7.56; CI 6.32–8.96), and 1.7% for men (53/3135; SMR 9.01; CI 6.75–11.78). Cardiovascular disorder was the dominant cause of death in both sexes and in all the investigated age groups (age 15–54 years; SMR 29.0; CI 9.42–67.71, age 55–74 years; SMR 6.12; CI 3.96–9.03, age 75 years: SMR 5.26; CI 3.74–7.19). The SMR decreased over the calendar year period notwithstanding a rising proportion of elderly individuals. In the most recent period, 1997–2004, the perioperative mortality rate was only 0.5%, which represents a normalization of the excess mortality risk during the first post-PTx year (SMR 1.17; CI 0.92–1.46).

Conclusion

PTx is a safe procedure, regardless of patient age. Today, the perioperative mortality risk is not a reason for excluding elderly patients from parathyroid surgery.
Recovery of suppressed male reproduction in mice exposed to progesterone during embryonic development by testosterone
Authors: Harini C , Sainath S B , Reddy P Sreenivasula
Published: November 2008

The present study aimed to examine whether transplacental exposure to progesterone caused male reproductive abnormalities and whether the changes can be reversed after testosterone administration. Progesterone was injected to mice on day 1, 3, and 7 of pregnancy. The male pups (F1 generation) were allowed to grow for 50 days and assessed for reproductive performance. Gestational exposure to progesterone (7 mg/kg body weight) resulted in significant body weight gain with a decrease in reproductive tissue indices in mice. Total sperm count, viable sperm, and motile sperm decreased in experimental mice. Hypo-osmotic swelling test revealed that experimental mice sperm membrane integrity was severely altered. The activity levels of testicular steroidogenic marker enzymes (hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase cluster (HSD3B) and hydroxysteroid (17-beta) dehydrogenase 1 (HSD17B)) decreased significantly in mice exposed to progesterone during embryonic development when compared with the controls. The levels of serum testosterone decreased with an increase in serum FSH and LH in mice exposed to progesterone during embryonic development. Prenatal exposure to progesterone caused significant reduction in the number of spermatozoa and increase in the lumen of seminiferous tubule. The experimental mice that cohabited with normal females showed fertility reduction. Administration of testosterone (4.16 mg/kg body weight) on postnatal day 20, 30, and 40 to progesterone-exposed prenates resulted in recovery of progesterone-induced suppressed male reproduction. It is suggested that the impairment of male reproduction in mice exposed to progesterone during embryonic development could be mediated through the inhibition of testosterone production. These results also indicate thatin uteroexposure to progesterone affects male reproduction and that supplementation of testosterone restores the suppressed male reproduction.