Characterization of the flow in the molten metal sump during direct chill aluminum casting

A recent analytical model for the liquid aluminum flow in a direct chill (DC) casting sump has been investigated and the scaling coefficients evaluated. The magnitudes of flow-field features, such as the depth of the temperature stratification in the sump and the velocity of the metal in the thermal boundary layer close to the solidification front, have been calculated. The results broadly agree with recent full numerical calculations of the flow in the sump. The variation of these essential flow features has been investigated across a range of typical ingot sizes, casting speeds, and superheats, and critical macro-casting-parameter combinations have been identified. The limitations of the model are discussed and the possible effects the identified structure has on macrosegregation are briefly explored. Finally, the influence on the flow field of the method of feeding the ingot is investigated, and it is concluded that the model and these results are not invalidated if the feeding is nonuniform over the top surface of the sump.     

Covalent immobilization of proteins onto (Maleic anhydride-alt-methyl vinyl ether) copolymers: enhanced immobilization of recombinant proteins

The amazing diversity of extant photosynthetic eukaryotes is largely a result of the presence of formerly free-living photosynthesizing organisms that have been sequestered by eukaryotic hosts and established as plastids in a process known as endosymbiosis. The evolutionary history of these endosymbiotic events was traditionally investigated by studying ultrastructural features and pigment characteristics but in recent years has been approached using molecular sequence data and gene trees. Two important developments, more detailed studies of members of the Cyanobacteria (from which plastids ultimately derive) and the availability of complete plastid genome sequences from a wide variety of plant and algal lineages, have allowed a more accurate reconstruction of plastid evolution.     

Teeth and trauma: res ipsa loquitur in a case of intubation

Autosomal dominant periodic fevers constitute a range of syndromes characterised by recurrent attacks of fever and abdominal pain. Familial Hibernian fever (FHF) has been described in only one United Kingdom based family, but two other Irish families have been found with similar clinical features. FHF resembles familial Mediterranean fever (FMF) in several clinical features, but the mode of inheritance of FHF is dominant whereas FMF is recessive. We have investigated whether autosomal dominant periodic fevers, in particular FHF, map to the FMF susceptibility locus (MEFV) on chromosome 16p13.3. We have used informative microsatellite markers flanking this locus to genotype members of the three families mentioned above. Two point and multipoint lod scores definitively excluded linkage to MEFV in the two larger families. A haplotype study confirmed these findings, indicating that FHF is genotypically as well as phenotypically distinct from FMF.     

A microstructural investigation of the origin of brittle behavior in the transverse direction in Mo-based alloy bars

The mechanical properties of commercial bars of Mo and a Mo alloy have been investigated. Although longitudinal mechanical properties are good, completely brittle behavior is invariably observed in samples tested in the transverse direction. The microstructures of these materials have been examined using optical metallography of bar stock, scanning electron microscopy of fracture surfaces, and Auger electron spectroscopy ofin situ fractured samples. A number of deleterious microstructural features has been identified; these include a large grain size in the transverse direction as a result of a 〈110〉 fiber texture and fractured carbide-crack stringers on grain boundaries. Oxygen segregation to grain boundaries has been shown not to be a factor contributing to brittle behavior. The origin of the carbides and the development of the associated cracks are described. A thermomechanical processing route, based on a recrystallization and forging procedure, has been developed to manufacture disc-shapes from which components having greatly improved mechanical properties can be produced.     

Growth and coarsening of g. p. Zones in Al- Zn alloys

The structural changes during the precipitation of G. P. zones in Al-Zn binary alloys have been investigated by means of anin situ small-angle scattering technique using synchrotron radiation. Defining a specific time, normalized by the half-completion time, the time-dependent evolution of the precipitation process can be divided into three periods, independent of alloy composition and quench-ing conditions. The structural and kinetic features of the first two periods have been analyzed in detail. The first stage represents a growing process of clusters with diffuse interface into the well-defined G. P. zones. The average size of these clusters increases, and the density decreases. The second stage corresponds to the Ostwald ripening process. This mechanism is described by utilizing a modified Lifshitz-Slyozov-Wagner theory.     

Relational properties and memory-based category construction.

Although many experiments have investigated factors that constrain perceptual category construction, there have been no investigations of factors that constrain memory-based (MB) category construction. Six experiments examined the extent to which perceptual and MB sorting were influenced by correlated dimensions, family resemblance principles, and conceptual knowledge. Sensitivity to many types of relational information (e.g., correlated features, causal relations, interactive properties of objects, and family resemblance relations) was observed with perceptual sorting, but these properties were rarely used to organize information in MB sorting conditions. Instead, there was a clear preference to organize categories around single dimensions. Even when perfectly correlated features were causally related, Ss in memory conditions did not use correlations to construct categories. The strengths and limitations of MB analyses and categorizations are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of hot pressing parameters on the strength of aluminum/stainless steel composites

Stainless steel fiber reinforced aluminum matrix composites have been fabricated by hot pressing under different conditions of temperature, pressure, and time. The variation in tensile strength of these composites has been studied in detail, and the hot pressing parameters have been optimized in order to fabricate composites having maximum strength at any fiber volume fraction. Microprobe analysis and Scanning Electron Microscopy of these composites have revealed interesting features of fiber/ matrix interface. These features have been found helpful in explaining the dependence of strength of the composites on hot pressing parameters.     

不锈钢板坯在结晶器中的凝固特性

通过拉漏坯壳厚度变化的实际测定结果,研究了板坯在结晶器中的凝固特性,提出了防止拉漏的措施。     

3D structural information as a guide to protein engineering using genetic selection

A great variety of protein systems have been investigated in the past year using structure-guided evolutionary strategies. On the basis of available 3D structural information, critical regions of proteins have been targeted for randomizing mutagenesis and active variants of the corresponding genes have been selected. These approaches help characterize structural and mechanistic features of proteins and have important implications for design.     

Effects of near-tip inhomogeneities on scattering of ultrasonic waves by cracks

The efficacy of ultrasonic methods to detect and characterize a crack depends on topographical features of the crack faces, the presence of inhomogeneities in the crack's environment, and the mechanical properties in the near-crack region. In this paper, the effects on the scattered ultrasonic field of various features of fatigue and stress corrosion cracks such as partial crack closure, the presence of microcracks and microvoids, and near-tip zones of different mechanical properties have been investigated. A representation integral for the scattered field has been used to formulate the ultrasonic scattering problem. Numerical results have been obtained for some canonical configurations. For the configurations examined in this paper, crack closure has the most significant effect on far-field scattering.     

Comparison of the influence of chromium and zirconium on the quench sensitivity of Al-Zn-Mg-Cu alloys

The role played by small additions of chromium and zirconium on the “quench-sensitivity” of Al-Zn-Mg-Cu high purity alloys has been studied. The effects of the quench rate reduction have been evaluated by mechanical testing; the associated microstructural features have been investigated by electron microscopy. The obtained data adequately explain the mechanisms of the “quench-sensitivity”.     

Primary immunodeficiency disorders

The primary immunodeficiency diseases are a relatively rare group of congenital disorders that are linked by the expression of an excessive number, duration, or severity of infections. The clinical features of most of the primary immunodeficiency diseases have been well described by astute physicians over several decades and have provided important clues to our basic understanding of human immunology. In contrast, the genetic basis and potential life-saving therapies for many of these disorders have been established only over the past few years. These recent advances have resulted in the prognosis of many of these disorders being largely dependent on their rapid recognition and treatment. Increased awareness of the differentiating epidemiologic, clinical, laboratory and genetic features of these diseases hold the promise of both furthering our understanding of basic human immunology and providing improved care for this challenging group of patients.     

Fatigue crack initiation and propagation of binder-treated powder metallurgy steels

Many of the targeted applications for powder-metallurgy materials, particularly in the automotive industry, undergo cyclic loading. It is, therefore, essential to examine the fatigue mechanisms in these materials. The mechanisms of fatigue-crack initiation and propagation in ferrous powder-metallurgy components have been investigated. The fatigue mechanisms are controlled primarily by the inherent porosity present in these materials. Since most, if not all, fatigue cracks initiate and propagate at the specimen surface, surface replication was used to determine the role of surface porosity in relation to fatigue behavior. Surface replication provides detailed information on both initiation sites and on the propagation path of fatigue cracks. The effect of microstructural features such as pore size and pore shape, as well as the heterogeneous microstructure on crack deflection, was examined and is discussed. Fracture surfaces were examined to elucidate a mechanistic understanding of fatigue processes in these materials.     

The pedophilic offender with antisocial character

The purpose of the study was to clarify how pedophilic offenders with antisocial character (psychopathy) differ from "ordinary" pedophilic offenders, among whom there are many persons with immaturity and contact difficulties. For this purpose all pedophilia cases subjected to mental examination during a period of 25 years were investigated. Of these 81 cases, 38 could be regarded as antisocial characters on the basis of the current diagnostic criteria. The others were regarded as controls. The criminals with antisocial character had also been involved in other kinds of crimes and had had hyperactivity problems more often than controls. The controls were often immature, had a low intelligence, and were less able to have relations with adult people than were antisocial characters. However, according to the present results, these features might also make criminals with antisocial character more susceptible to pedophilia.     

Adolescents'' promotion of nonsmoking and smoking

Intraepithelial neoplasia of the female genital tract has long been associated with human papillomavirus infection. To date, there have been no previously published studies of oral dysplasia that have identified light microscopic features predictive of the presence of human papillomavirus. We identified a variant of oral epithelial dysplasia, koilocytic dysplasia, that exhibited light microscopic features suggestive of HPV infection. To determine if these microscopic features were specifically correlated with human papillomavirus infection, DNA in situ hybridization for human papillomavirus 6/11, 16/18, and 31/33/51 was performed on 31 lesions diagnosed histologically as koilocytic dysplasia. Seventeen matched control cases of conventional oral epithelial dysplasia were also analyzed for human papillomavirus. Human papillomavirus DNA was detected significantly more often (p < 0.001) in koilocytic dysplasia (80.6%) than conventional oral epithelial dysplasia (0.0%). Positive cases of koilocytic dysplasia contained either intermediate-risk (31/33/51) or high-risk (16/18) human papillomavirus types whether or not they contained low-risk human papillomavirus types (6/11). The histologic and clinical presentation of koilocytic dysplasia was unique. Lesions demonstrated koilocytes and other microscopic characteristics of human papillomavirus infection, as well as features of conventional epithelial dysplasia. A striking male predominance was noted, as was a relatively young average age of presentation (39.0 years). On the basis of our preliminary analysis, we conclude that oral koilocytic dysplasia represents a unique pathologic entity and that the presence of human papillomavirus can be predicted on light microscopy with at least 80% accuracy. The clinical significance and potential for malignant transformation of koilocytic dysplasia remain to be investigated.     

对溴苯甲醚的合成研究

对溴苯甲醚是合成许多有机化合物的重要中间体，本文探讨了反应条件，试剂用量以及改进的两条合成路线对合成对溴苯甲醚产率的影响，经改进的合成方法反应条件温和、操作简便、产率更高。     

Minimal-deviation endometrioid adenocarcinoma of the uterine cervix. A report of five cases of a distinctive neoplasm that may be misinterpreted as benign

We describe five cervical adenocarcinomas with unusual, deceptively benign histological features that occurred in women 34 to 42 years of age and caused problems in interpretation. The tumors were incidental findings in hysterectomy or cone-biopsy specimens in four patients; the fifth patient was investigated because abnormal glandular cells were found on a Papanicolaou smear. One patient had been exposed in utero to diethylstilbestrol. The cervix is known to have been abnormal on gross evaluation in only one case. Microscopic examination disclosed a deceptively benign-appearing proliferation of glands and cysts for the most part unassociated with a stromal reaction. Cilia were present in four neoplasms and apical snouts in three. Features that indicated the neoplastic nature of the glandular proliferation in these cases, to varying extents in individual cases, included the number of glands and their distribution, the shapes of the glands, their presence deep in the cervical wall, the focal presence of a stromal reaction, and moderate cytologic atypicality with occasional mitotic figures. None of the tumors is known to have recurred or metastasized. In our opinion, these distinctive neoplasms represent minimal-deviation endometrioid adenocarcinomas of the cervix.     

The ultrastructure of the rabbit submandibular gland

The secretory granules of the terminal and pre-terminal tracts of the rabbit submandibular gland display distinct features, while the cell morphology is quite similar. Among these cells, some smaller ones presenting an highly dilated endoplasmic reticulum have been identified in the pre-terminal tracts. Some hypothesis have been formulated concerning the function of these cells.     

Advanced directives: do they really mean what they mean?

Basaloid squamous cell carcinoma (BSCC) is an aggressive variant of squamous cell carcinoma (SCC) that was first described in 1986. In the English literature, only 28 cases of this histopathological entity have been reported in the larynx. Proliferative features of this infrequent tumor were investigated by proliferating cell nuclear antigen immunoreactivity, and the presence of P53 mutation was also investigated in a series of 4 cases. BSCC was found to share similar features with regular SCC in terms of its proliferation rate and P53 mutation positivity, as well as biological behavior and clinical outcome.     

Hydraulics of Circular Drop Manholes

Circular drop manholes are widely employed in steep urban drainage systems. Drop manholes may lead to poor hydraulic conditions if their energy dissipation is inadequate. The dominant hydraulic features of drop manholes depend on the flow regimes, characterized in terms of the dimensionless impact parameter. Depending on the latter parameter, the energy dissipation can vary within large limits, affecting thereby the downstream flow features. Also, the water pool depth inside the manhole and the air entrainment have been studied in terms of both the hydraulic and geometric parameters. Moreover, the conditions for which a drop manhole generates flow choking at its inlet or outlet have been investigated. Empirical equations for practical manhole design are provided. The importance of suitable manhole aeration is highlighted.