Some aspects of deformation behavior of Coarse Multiphase Metallic Materials

The deformation behavior of several single- and two-phase coarse microstructures has been examined using microhardness measurements. It has been found that the strength response of a coarse phase in isolation is distinctly different from its response when it exists in a two-phase system. The second phase alters the mechanical state of the first one andvice versa even in the plastically undeformed condition. This phenomenon is explained in terms of the existence of an appreciable amount of residual stresses in two-phase coarse microstructures. These stresses primarily arise due to the difference in thermal expansion coefficients of the phases. The in- fluence of elastic stress field on microhardness response is shown with a new type of experiment to support the proposed explanation. The present results question the existing expressions for deformation modeling of multiphase materials because of the uncertainties in the estimation of the average strength of the phases in a two-phase system.     

Some aspects of deformation behavior of coarse multiphase metallic materials

The deformation behavior of several single-and two-phase coarse microstructures has been examined using microhardness measurements. It has been found that the strength response of a coarse phase in isolation is distinctly different from its response when it exists in a two-phase system. The second phase alters the mechanical state of the first one andvice versa even in the plastically undeformed condition. This phenomenon is explained in terms of the existence of an appreciable amount of residual stresses in two-phase coarse microstructures. These stresses primarily arise due to the difference in thermal expansion coefficients of the phases. The influence of elastic stress field on microhardness response is shown with a new type of experiment to support the proposed explanation. The present results question the existing expressions for deformation modeling of multiphase materials because of the uncertainties in the estimation of the average strength of the phases in a two-phase system.     

Some aspects of impotence

The fine structure of human nasal sero-mucinous glands was studied in 15 chronic allergic patient. There was total absence of the mucous glands, and proliferation of seroud elements, with hugely dilated lumina containing large numbers of intact zymogen granules, and absence of microvilli. The relation between the goblet cells and the nasal glands was discussed. An interchange between the serous and mucous elements was deduced.     

Densification and deformation behavior

The relationships between the longitudinal and thickness strains and between the apparent plastic Poisson's ratio and the relative density achieved during hot rolling of porous nickel strips of initial relative densities 0.36, 0.48, and 0.67 are experimentally determined. The experimental data have been found to agree well with the results predicted from analytical relationships. Hot rolling of such porous metal strips can be divided into three distinct stages. In stage I, the powder particles rearrange and restack as the rolling progresses and the longitudinal elongation and apparent plastic Poisson's ratio are negligibly low. The end of this stage is marked by the situation when no further densification without longitudinal flow is possible by hot rolling. In the present case, stage I continues until a relative density of 0.7 has been achieved in the strip, resulting into a predominantly orthorhombic pattern of particle arrangement. Stage II,i.e., densification from the relative density from 0.70 to 0.95, is associated with the continuous increase in interparticle contact area, longitudinal elongation, and apparent plastic Poisson's ratio as the hot rolling progresses. In this stage, the interconnected porosity changes to the isolated one. In stage III,i.e., densification beyond the relative density of 0.95, pore fragmentation and collapsing of the opposite pore surfaces take place until all the porosity has been eliminated. PRADIP K. BAGDI, formerly Graduate Student, PRADIP K. BAGDI, formerly Graduate Student,     

Some neurophysiologic aspects of consciousness

This article presents the results of an assessment of gynecological morbidity among 385 women with young children residing in a district of Karnataka State, South India. All three main modes of assessment (clinical examination, laboratory tests, and self-reports) reveal a high burden of reproductive tract infections. The two most common conditions, identified by laboratory tests, were bacterial vaginosis and mucopurulent cervicitis. Approximately one-fourth of the women had clinical evidence of pelvic inflammatory disease, cervical ectopy, and fistula. The contribution of sexually transmitted diseases to overall gynecological morbidity appears to be relatively modest; 10 percent were so diagnosed. Associated conditions of anemia and chronic energy deficiency were common. Severe anemia was found in 17 percent of cases and severe chronic energy deficiency in 12 percent. These results indicate that radical improvements in women's health in India will require far more than the diagnosis and treatment of reproductive tract infections.     

Some aspects of zygomaticomaxillary fractures

A better understanding of the effects of energy deposited in cells by incorporated isotopes can be expected from an analysis of differential cell doses. With this thought in mind, the distributions of specific energies in tissue were calculated for 239Pu and 131I. A program written in Fortran IV makes use of a matrix of spherical cells and cell nuclei of 10 and 8 mum diameter, respectively. The cells are arranged in close-packed structure. The radioactivity is considered as being compiled to point sources of 1 dps activity. The sources are located in the common centers of cells and nuclei. The calculations yield discrete values of specific energy using the mass of the nuclei for mass of reference. The numbers of cell nuclei receiving given amounts of specific energy are functions of the specific activity of the isotopes in the tissue. The specific activity is varied by changing the number of sources per g of tissue. The program also allows to calculate the numbers of cell nuclei with zero energy deposition. From the 1 dps point sources an average specific energy of 831 rads/h results for plutonium for cell nuclei within the range of the 5.14 MeV alpha-particles. For iodine, the value is 35 mrads/h within the range of the beta-particles of 188 KeV mean energy. If the volumes irradiated by the sources begin to overlap these values begin to increase accordingly.     

Some aspects of cervical chordoma

This paper reviews 13 cases of chordoma in the cervical spine and base of the skull which have been seen at the Pack Medical Foundation over the past 25 years. Chordomas are dysonto genetic, malignant, slow-growing neoplasms that arise in remnants of the embryonic notochord. Concealed along the axial skeleton, these slow-growing tumors are usually well entrenched before they are accurately diagnosed. The majority of the chordomas of the spine occur in the sacroccygeal region. Of the 13 cases in the area of the cervical spine, 39% occurred in the region of the base of the skull and 61% in the area of the cervical spine. The treatment of the cervical tumors consisted of laminectomy to relieve the pressure on the cord and to remove as much of the neoplasm as possible. Some of the tumors at the base of the skull were nonresectable and were treated with radiotherapy. Radiotherapy was ultimately used in every case, either in combination with surgery or as a primary or subsequent method of management. The overall prognosis for palliation was fair but ineffective for cure.     

Ti-Al-Nb-W合金的高温变形行为

在Thermecmastor-Z动态热模拟试验机上对Ti-43Al-4Nb-1.4W合金进行高温压缩变形实验,实验温度范围为1 050~1 150℃,应变速率范围为0.001~1 s 1。根据该合金的真应力-真应变曲线,建立合金高温变形的本构方程和热加工图,并对不同变形区域的组织进行分析。结果表明:Ti-43Al-4Nb-1.4W合金高温压缩变形峰值应力与变形条件的关系可用双曲正弦函数来表示,其变形激活能为567.05 kJ/mol,高温变形的本构方程为:ε=3.37×1018.[sinh(0.0043σ)]3.27exp[567.05/(RT)];加工图显示该合金最佳加工区域的应变速率为0.001~0.01 s 1(η范围在40%~55%),在此加工区域内合金发生较明显的动态再结晶和β相的球化。     

金属层合板板形翘曲变形行为

采用经典弹性力学方法建立了金属层合板翘曲解析计算力学模型,获得了厚度方向不均匀延伸与板形翘曲之间的定量关系;并分别建立了在线和离线两种状态下金属层合板翘曲变形的有限元数值模拟模型,对解析计算力学模型进行了验证;在此基础上,揭示了金属层合板产生板形翘曲缺陷的力学根源以及各因素对金属层合板板形翘曲缺陷演变的影响规律,同时对比分析了双层和三层结构层合板与均质板的翘曲变形差异以及铜/碳钢层合板与不锈钢/碳钢层合板二者之间的翘曲变形差异。研究表明,金属层合板翘曲高度与延伸差、厚度比呈正比关系,与厚度呈反比关系,且基层与覆层的切变模量相差越大,厚度比对金属层合板翘曲变形的影响越大。基于数值模型,模拟研究了层合板在理想均匀分布的初始温度下,历经去应力退火过程时,其板形翘曲的变形行为及规律,并与均质板进行比较。最后,在工业生产现场取样已翘曲层合板,通过测量其弯曲变形量进而反求其初始延伸差,验证了解析计算力学模型的准确性。      

Some current aspects of environmental fluoride

This review presents a Total Environment evaluation of current inorganic fluoride intake by human populations. Inorganic fluoride is a persistant bioaccumulator, and the ever-increasing use (and release) of fluoride compounds in the environment should be of long-term concern in population sub-groups who are most susceptible, and therefore, most "at risk". One of these sub-groups consists of people with impaired kidney function, including subjects with nephorphatic diabetes. The diabetes factor is of particular relevance, not only because the incidence of diabetes has increased by 6%/yr during the period 1965-1975, but also because subjects with nephropathic diabetes can exhibit a polydipsia-polyurea syndrome that results in increased intake of fluoride, along with greater-than-normal retention of a given fluoride dosage. People with inadequate dietary intakes (particularly of Ca and/or Vitamin C) are also likely to be more "at risk" as a consequence of low-dose long-term fluoride ingestion. Evidence is presented, showing that there has been an escalation in dialy fluoride intake via the total human food-and-beverage chain, with the likelihood that this escalation will continue in the future. Recent observations, relating to an increasing incidence of chronic fluoride intoxication among humans, is also emphasized.     

Some legal aspects of mental capacity

This article discusses some practical matters which arise when competence to make decisions is in question. Consent, testamentary capacity, powers of attorney, the Court of Protection, "living wills," and research on people with dementia are briefly considered.     

Some genetic aspects of ovarian tumors

BACKGROUND: Propranolol and isosorbide-5-mononitrate (ISMN) are increasingly used in the prophylaxis of variceal haemorrhage in cirrhosis. However, recent studies have suggested that these drugs may compromise renal function, possibly by reducing renal blood flow. AIMS: To assess the acute effects of propranolol and ISMN on renal blood flow and other haemodynamic parameters in cirrhosis. PATIENTS AND METHODS: Twenty six cirrhotic patients were given either 80 mg propranolol, 20 mg ISMN, or a combination of the two drugs. Unilateral renal blood flow (RBF), azygos blood flow (AZBF), hepatic venous pressure gradient (HVPG), mean arterial pressure (MAP), and heart rate (HR) were recorded prior to and one hour after drug administration. RESULTS: Propranolol caused a reduction in HR (p < 0.005), AZBF (p < 0.01), and HVPG (p = 0.05), but no change in MAP or RBF (454.1 (77.3) versus 413.9 (60.3) ml/min). ISMN reduced MAP (p < 0.005) and HVPG (p < 0.01), but had no effect on HR, AZBF, or RBF (302.5 (49.4) versus 301.7 (58.8) ml/min). Combined treatment reduced MAP (p < 0.005), AZBF (p < 0.05), and HVPG (p = 0.002), but HR and RBF (419.2 (62.6) versus 415.1 (61.1) ml/min) remained unchanged. CONCLUSIONS: Despite the anticipated changes in other haemodynamic parameters, acute propranolol and/or ISMN administration did not reduce RBF. These drugs do not seem to compromise RBF in cirrhosis.     

Some cognitive aspects of motivation.

Consider the possibility that "what we call motives are really a particular kind of perceptual or cognitive event… . We desperately need to discover the dimensions of motivated behavior." Factors discussed relating to motivated behavior include difficulty and novelty (encompassing change, unpredictability, and surprise). The cognitive approach to motivation is most promising in esthetics. The "cognitive contribution to why we do what we do is an important one. It is also one that we know very little about." Behavioral facts and relationships must precede a physiological theory of motivation. From Psyc Abstracts 36:01:3CC03P. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some aspects of tyrosine secondary metabolism

p53 tumor suppressor gene controls cell response to a variety of stresses inducing growth arrest or apoptosis in damaged cells. It largely determines the sensitivity of tumor and normal cells to radiation and chemotherapy, and, therefore, defines both the efficacy and limitations of anti-cancer treatment. To determine molecular mechanisms of p53-dependent stress response in normal tissues we identified and compared the spectra of radiation-responsive genes in cells of different origin and p53 status using a cDNA array hybridization technique. The majority of genes identified were p53-dependent and cell type specific. Several of the new p53 responders encode known secreted growth inhibitory factors. This suggests that p53, in addition to its intrinsic antiproliferation activity, can cause 'bystander effect' by inducing export of growth suppressive stimuli from damaged cells to neighboring cells. Consistently, a p53-dependent accumulation of factors, which causes growth inhibitory effects in a variety of cell lines, was found after gamma irradiation in the media from established and primary cell cultures and in the urine of irradiated mice. Moreover, p53-dependent factors released by normal human fibroblasts potentiated the cytotoxic effect of a chemotherapeutic drug on co-cultivated tumor cells. This suggests a previously unknown role for normal cells in chemo- and radiation therapy of cancer.