Influence of crack closure on the stress intensity factor for plates subjected to bending—A 3-D finite element analysis

Plates with central through cracks subjected to bending is analysed taking into account the closure of the crack faces on the compression side. A three-dimensional finite element method employing three-dimensional degenerate solid element is used for the analysis. The crack faces have been modelled such that they come in contact over an area on the compression side and interfere with each other. The influence of the crack closure on the variation of the stress intensity factor across the plate thickness is obtained for finite and infinite plate geometries.     

An implementation of distributed shared memory

Shared memory is a simple yet powerful paradigm for structuring systems. Recently, there has been an interest in extending this paradigm to non-shared memory architectures as well. For example, the virtual address spaces for all objects in a distributed object-based system could be viewed as constituting a global distributed shared memory. We propose a set of primitives for managing distributed shared memory. We present an implementation of these primitives in the context of an object-based operating system as well as on top of Unix.     

The specificity of the N-terminal SH2 domain of SHP-2 is modified by a single point mutation

SH2 domains are small protein domains of approximately 100 amino acids that bind to phosphotyrosine (pY) in the context of a specific sequence surrounding the target pY. In general, the residues C-terminal to the pY of the binding target are considered most important for defining the binding specificity, and in particular the pY + 1 and pY + 3 residues (i.e., the first and third amino acids C-terminal to the pY). However, our previous studies with the SH2 domains of the protein tyrosine phosphatase SHP-2 [Huyer, G., Li, Z. M., Adam, M., Huckle, W. R., and Ramachandran, C. (1995) Biochemistry 34, 1040-1049] indicated important interactions with the pY - 2 residue as well. In the SH2 domains of SHP-2, the highly conserved alphaA2 Arg is replaced by Gly. A comparison of the published crystal structures of the Src SH2 domain and the N-terminal SH2 domain of SHP-2 complexed with high-affinity peptides suggested that the alphaA2 Gly of SHP-2 creates a gap which is filled by the side chain of the pY - 2 residue of the bound peptide. It was predicted that replacing this Gly with Arg would alter or eliminate the involvement of the pY - 2 residue in binding. The alphaA2 Gly --> Arg mutant was constructed, and indeed, this mutant no longer required residues N-terminal to the target pY for high-affinity binding, making its specificity more like that of other SH2 domains. The alphaA2 Gly is clearly involved in directing the unusual requirement for the pY - 2 residue in the binding sequence of this SH2 domain, which has important implications for its in vivo targeting and specificity.     

Design of Compact D-shaped Frequency Reconfigurable Slot Antenna for Ku/K Band Applications

Wireless Personal Communications - In this paper, a new compact design of frequency reconfigurable slot antenna is presented. The proposed radiating patch consists of two symmetrical D shape slots...     

Implementation of an 8-Core, 64-Thread, Power-Efficient SPARC Server on a Chip

The second in the Niagara series of processors (Niagara2) from Sun Microsystems is based on the power-efficient chip multi-threading (CMT) architecture optimized for Space, Watts (Power), and Performance (SWaP) [SWap Rating = Performance/(Space _* Power) ]. It doubles the throughput performance and performance/watt, and provides >10times improvement in floating point throughput performance as compared to UltraSPARC T1 (Niagara1). There are two 10 Gb Ethernet ports on chip. Niagara2 has eight SPARC cores, each supporting concurrent execution of eight threads for 64 threads total. Each SPARC core has a floating point and graphics unit and an advanced cryptographic unit which provides high enough bandwidth to run the two 10 Gb Ethernet ports encrypted at wire speeds. There is a 4 MB Level2 cache on chip. Each of the four on-chip memory controllers controls two FBDIMM channels. Niagara2 has 503 million transistors on a 342 mm² die packaged in a flip-chip glass ceramic package with 1831 pins. The chip is built in Texas Instruments' 65 nm 11LM triple-Vt CMOS process. It operates at 1.4 GHz at 1.1 V and consumes 84 W.     

Synthesis of transfer functions by nonsymmetrical lattice networks using lossy coils

A method for realising a v.t.f.by a nonsymmetrical lattice in which all coils can be made lossy is given.     

Design of 2-D recursive digital filters satisfying prescribed magnitude and constant group delay response

Generation of the 2-variable very-strictly-Hurwitz polynomial (VSHP) using properties of derivatives of even or odd parts of Hurwitz polynomials and their applications in designing 2-D recursive digital filters satisfying prescribed magnitude and constant group delay response is described.     

Optimal Equalization of Discrete Signals Passed Through a Random Channel

The problem of equalizing a discrete signal that has been transmitted through a channel selected at random from an ensemble of channels is considered. Using mean-square error as the performance index, the minimum number of adjustable parameters required to achieve a given level of performance is sought. For certain special cases, it is shown that, using nonrecursive sampled data filters, the optimum tap weights are given by the eigenvectors of the matrix formed from the covariances of the channel's impulse response. A numerical algorithm is developed to find the optimum equalizer structure for a wide class of channels with the restriction that the number of channels in the given ensemble is finite. Results worked out for several examples show that the optimum equalizer structure requires significantly fewer adjustable parameters than the standard transversal equalizer in order to obtain the same level of performance.     

A hybrid fuzzy neural network-expert system for a short term unit commitment problem

The major aim of this paper is to develop a hybrid model to determine the unit commitment schedule of generating units. It is proposed to produce the unit commitment schedules in two steps. In the first step, the input layer of the neural network is designed to adopt nonlinear fuzzy membership values of the load demand profile. In the second step, an adaptive expert system is used to manipulate the schedules by using rule-base and inference mechanism. To demonstrate the effectiveness of this model, extensive studies have been performed for different load profiles belonging to the power systems of Tamilnadu consisting of thermal, nuclear, hydro, wind and diesel power plants.     

Convulsions with meningiomas: incidence and significance

In a study of a consecutive series of 127 surgically treated meningiomas, it was found that 29% of the patients had reported with convulsions as their initial symptom. In this group, surgical excision of the meningioma stopped the convulsions in about half of the patients, but the others continued to have seizures after their operations. Among those patients with meningiomas who did not have preoperative convulsions, about one-sixth (15 patients) developed postoperative seizures. Patients in both groups required prolonged anticonvulsant medication. Factors predisposing to the occurrence of postoperative seizures were the site of the tumor, faulty surgical technique, and a preoperative history of seizures.