Deformation behaviour of bulk materials during repetitive upsetting-extrusion (RUE)

Repetitive upsetting-extrusion (RUE) that was originally invented to process powder materials for bulk mechanical alloying is currently being used to process bulk materials. Bulk materials are subjected to severe plastic deformation using the same die design that was used to process powder materials. As the deformation behaviour of powder and bulk materials are quite different, it has to be evaluated whether a single die design is suitable to process both these materials. Further, information on the deformation behaviour and strain homogeneity that can be achieved by subjecting bulk materials to RUE process are also currently not available. To address these issues, both numerical analysis and actual experiments on commercial pure copper has been carried out. The results obtained are presented and discussed here     

Characteristics of gold/cadmium sulfide nanowire Schottky diodes

Schottky diode junctions were formed between nanowires of cadmium sulfide and nanowires of gold, through sequential cathodic electrodeposition into the pores of anodized aluminum oxide (AAO) templates. Lengths of CdS and Au nanowires were 100-500 nm and 300-400 nm respectively, while the diameter was 30 nm, each. Analysis of Schottky diodes yielded an effective reverse saturation current (J_o), of 0.32 mA/cm² and an effective diode ideality factor (A) of 8.1 in the dark. Corresponding values under one sun illumination were, J_o = 0.92 mA/cm² and A = 10.0. Dominant junction current mechanisms are thought to be tunneling and/or interface state recombination.     

Effect of friction model in numerical analysis of equal channel angular pressing process

During the last decade or so there has been a tremendous growth in the research and development of equal channel angular pressing (ECAP) process which was originally proposed by Segal et al. Numerical analyses are being used extensively to evaluate the effect of various die design and process parameters in ECAP. Friction is one such important parameter. Coulomb and shear friction models have been used in the numerical analysis of ECAP process and contradicting results have been reported. This study evaluates the effect of coulomb and shear friction models on the deformation pattern, strain distribution and load requirement during ECAP process and suggests which friction model should be used in the numerical analysis of ECAP process.     

Lymphatics in Tumor Progression and Immunomodulation

The lymphatic system consists of a unidirectional hierarchy of vessels responsible for fluid homeostasis, lipid absorption, and the transport of immune cells and antigens to secondary lymphoid organs. In cancer, lymphatics play complex and heterogenous roles that can promote or inhibit tumor growth. While lymphatic proliferation and remodeling promote tumor dissemination, functional lymphatics are necessary for generating an effective immune response. Recent reports have noted lymphatic-dependent effects on the efficacy of immunotherapy. These findings suggest that the impact of lymphatic vessels on tumor progression is organ- and context-specific and that a greater understanding of the interaction of tumor cells, lymphatics, and the tumor microenvironment can unveil novel therapies.     

Tumor-Associated Lymphatics Upregulate MHC-II to Suppress Tumor-Infiltrating Lymphocytes

Steady-state lymphatic endothelial cells (LECs) can induce peripheral tolerance by presenting endogenous antigens on MHC class I (MHC-I) molecules. Recent evidence suggests that lymph node LECs can cross-present tumor antigens on MHC-I to suppress tumor-specific CD8+ T cells. Whether LECs can act as immunosuppressive cells in an MHC-II dependent manner in the local tumor microenvironment (TME) is not well characterized. Using murine heterotopic and spontaneous tumor models, we show that LECs in the TME increase MHC-II expression in the context of increased co-inhibitory signals. We provide evidence that tumor lymphatics in human melanoma and breast cancer also upregulate MHC-II compared to normal tissue lymphatics. In transgenic mice that lack LEC-specific MHC-II expression, heterotopic tumor growth is attenuated, which is associated with increased numbers of tumor-specific CD8+ and effector CD4+ T cells, as well as decreased numbers of T regulatory CD4+ cells in the TME. Mechanistically, we show that murine and human dermal LECs can take up tumor antigens in vitro. Antigen-loaded LECs in vitro can induce antigen-specific proliferation of CD8+ T cells but not CD4+ T cells; however, these proliferated CD8+ T cells have reduced effector function in the presence of antigen-loaded LECs. Taken together, our study suggests LECs can act as immunosuppressive cells in the TME in an MHC-II dependent manner. Whether this is a result of direct tumor antigen presentation on MHC-II requires additional investigation.     

Fuzzy additive hybrid operators for network-based decision making

Evidence Aggregation Networks based on multiplicative fuzzy hybrid operators were introduced by Krishnapuram and Lee. They have been used for image segmentation, pattern recognition, and general multicriteria decision making. One of the drawbacks to these networks is that the training is complex and quite time consuming. In this article, we modify these aggregation networks to implement additive fuzzy hybrid connectives. We study the theoretical properties of two classes of such aggregation operators, one where the union and intersection components are based on multiplication, and the other where these components are derived from Yager connectives. These new networks have similar excellent properties such as backpropagation training and node interpretability for decision making under uncertainty as do their multiplicative precursors. They also have the advantage that training is easier since the derivatives of the additive hybrid operators are not as complex in form. the appropriate training algorithms are derived, and several examples given to illustrate the properties of the networks. © 1994 John Wiley & Sons, Inc.     

A scalability test for parallel code

Code scalability, crucial on any parallel system, determines how well parallel code avoids becoming a bottleneck as its host computer is made larger. The scalability of computer code can be estimated by statistically designed experiments that empirically approximate a multivariate Taylor expansion of the code's execution response function. Each suspected code bottleneck corresponds to a first-order term in the expansion, the coefficient for that term indicating how sensitive execution is to changes in the suspect location. However, it is the expansion coefficients for second-order interactions between code segments and the number of processors that are fundamental to discovering which program elements impede parallel speedup. A new, unified view of these second-order coefficients yields an informal relative scalability test of high utility in code development. Discussion proceeds through actual examples, including a straightforward illustration of the test applied to SLALOM, a complex, multiphase benchmark. A quick graphical shortcut makes the scalability test readily accessible.     

Rational bitmap scaling

A simple mathematical approach is presented for scaling a bitmap image by a rational factor without interpolation. The transformation is reversible. As application of these results, we present a step-by-step scaling algorithm.     

TEAM BUILDING FOR IS SUCCESS

The growth of end-user computing and increased service options available to users maximize the importance of well-managed user relations. Team building, a method of changing people's attitudes and behavior, helps IS managers earn users' trust and generate the enthusiasm necessary to complete projects successfully.     

Parallelism in logic programs

There is a tension between the objectives of avoiding irrelevant computation and extracting parallelism, in that a computational step used to restrict another must precede the latter. Our thesis, following [3], is that evaluation methods can be viewed as implementing a choice ofsideways information propagation graphs, or sips, which determines the set of goals and facts that must be evaluated. Two evaluation methods that implement the same sips can then be compared to see which obtains a greater degree of parallelism, and we provide a formal measure of parallelism to make this comparison.Using this measure, we prove that transforming a program using the Magic Templates algorithm and then evaluating the fixpoint bottom-up provides a most parallel implementation for a given choice of sips, without taking resource constraints into account. This result, taken in conjunction with earlier results from [3,27], which show that bottom-up evaluation performs no irrelevant computation and is sound and complete, suggests that a bottom-up approach to parallel evaluation of logic programs is very promising. A more careful analysis of the relative overheads in the top-down and bottom-up evaluation paradigms is needed, however, and we discuss some of the issues.The abstract model allows us to establish several results comparing other proposed parallel evaluation methods in the logic programming and deductive database literature, thereby showing some natural, and sometimes surprising, connections. We consider the limitations of the abstract model and of the proposed bottom-up evaluation method, including the inability of sips to describe certain evaluation methods, and the effect of resource constraints. Our results shed light on the limits of the sip paradigm of computation, which we extend in the process.