Computer Simulation of Hydrostatic Co-Extrusion of Bimetallic Compounds.

A study of hydrostatic co-extrusion of a hard-core/soft-clad bi-metallic compound has been conducted. The research employs the Sachs\u27 boring-out technique to determine the residual stress distribution in a hydrostatically co-extruded copper-clad Gildcop composite. A parallel simulation of the residual stress distribution in such composites extruded to extrusion ratios of 2.25, 4.0, and 7.5 was conducted using the ABAQUS finite element code. The version of the code employed uses an elastic-plastic constitutive law for material behavior and does not simulate deformation heating effects. Data for the mechanical properties were obtained experimentally by constant true strain-rate tests on material identical to that used in the extrusion experiments. The results indicate that the extrusion pressure varies linearly with the natural logarithm of the extrusion ratio. The simulation results obtained for this pressure, however, are generally higher than those found in experiments. Comparison of the experimental and numerical results of the residual stresses indicate that although the two results are qualitatively similar, they are quantitatively different. In all cases, the experimental results were much lower than those of numerical calculations, implying that some recovery has occurred during the extrusion process. The investigation shows, however, that finite element analysis in conjunction with experimental measurements can be applied successfully to predict and verify the qualitative residual stress patterns developed in hydrostatically extruded products

Changing QRS Morphology: What is the mechanism?

ECG in sinus rhythm with ventricular preexcitation and changing QRS morphology was seen that was initially interpreted as the multiple accessory pathway from elsewhere. (Figure 1A). The following mechanisms are potentially involved in the electrogenesis of changing QRS morphology in WPW syndrome: 1) multiple accessory pathways1; 2) simultaneous occurrence of aberrant atrioventricular conduction with accessory pathway conduction 2; 3) ventricular fusion of preexcited sinus impulse with ectopic impulse. Electrophysiologic study showed short PR (75 ms) interval with wide QRS (152 ms) and negative HV (-12 ms) interval. No change in delta wave polarity was observed during HRA and CS pacing. In full preexcitation, no breakthrough was seen in the CS. During incremental ventricular pacing, atrial breakthrough site is initially recorded on the HRA catheter and then changed to distal pole of CS catheter with progressive decrease in pacing cycle length. During ventricular pacing at cycle length of 500 ms (S1), earliest atrial activity is recorded on HRA catheter. Changing QRS could not be explained by presence of multiple APs because only right-sided AP had bidirectional conduction and no distal CS breakthrough was seen simultaneous with changing QRS morphology. The possibility of aberrant conduction is excluded by presence of negative HV interval in the beats with differing QRS morphology. No sinus cycle length variation before and after the beats with different morphologies are against the occurrence of functional LBBB. The prematurity of ventricular electrogram in His recording catheter with variable HV (H-electrogram is recorded after V-electrogram in second beat and before V-electrogram in third beat) and fixed V-RB intervals (interval from ventricular electrogram in His to the RB potential) are compatible with ventricular fusion of preexcited sinus impulse with ectopic ventricular impulse originating from parahissian area (explaining LBBB and inferior axis morphology of the beats with changing QRS) but not from the His bundle or RBB itself (because H-electrogram and RB potential is recorded after V-electrogram in the second beat with greater degree of ventricular fusion)(Figure 1B)

LTE-advanced, and the way forward

Long Term Evolution Advanced (LTE-Advanced) is the next step in LTE evolution and allows operators to improve network performance and service capabilities through smooth deployment of new techniques and technologies. LTE-Advanced uses some new features on top of the existing LTE standards and protocols to provide better user experience and higher throughputs. Some of the most significant features introduced in LTE-Advanced are carrier aggregation, enhancements in heterogeneous networks, coordinated multi-point transmission and reception, enhanced Multiple Input Multiple Output (MIMO) usage and deployment of relay nodes in the radio network. This paper presents an overview of the key features and functionalities of the LTE-Advanced radio access network supported by simulation results, and provides discussion on the current challenges, roadmap and the way forward from LTE-Advanced toward future mobile communications systems

Semantics of "Verse" in the Qur'an in the light of the Syntagmatic and Paradigmatic Relations

One of the most frequent words of the Holy Qur'an is "Verse", whose association with various vocabularies has provided a very broad semantic field for the term. Therefore understanding the conceptual scope and thus the precise explanation of its semantic domain is indispensable in order to properly understand the Divine Viewpoint. This paper with an analytical-descriptive method and in the light of the Syntagmatic and Paradigmatic relations studies the semantic domain of "verse" in the semantic system of the Qur'an, and explains the semantic differences in the conjunctive fields and also the assessment of different semantic relations; and has concluded that in the discourse of the Qur'an, the "verse" is used to express the relation between sign and meaning, the sign that is sometimes used in genetic affairs, sometimes in religious affairs, and in tangibles  and Intangibles affairs, and its purpose is to pay attention to some matters including materiality and spirituality for the sake of peace and security. The semantics of the verse with regard to Syntagmatic and Paradigmatic relations as well as lexical proofs, which support the semantic findings, indicate that the divine verses are a sign of attaining guidance, thanks, piety, science, certainty, thought , remembrance and .... In fact, God has revealed His genetic and religious verses to man with the purpose of providing a foundation for faith, which ultimately leads to peace and security

A Survey From Distributed Machine Learning to Distributed Deep Learning

Artificial intelligence has achieved significant success in handling complex tasks in recent years. This success is due to advances in machine learning algorithms and hardware acceleration. In order to obtain more accurate results and solve more complex problems, algorithms must be trained with more data. This huge amount of data could be time-consuming to process and require a great deal of computation. This solution could be achieved by distributing the data and algorithm across several machines, which is known as distributed machine learning. There has been considerable effort put into distributed machine learning algorithms, and different methods have been proposed so far. In this article, we present a comprehensive summary of the current state-of-the-art in the field through the review of these algorithms. We divide this algorithms in classification and clustering (traditional machine learning), deep learning and deep reinforcement learning groups. Distributed deep learning has gained more attention in recent years and most of studies worked on this algorithms. As a result, most of the articles we discussed here belong to this category. Based on our investigation of algorithms, we highlight limitations that should be addressed in future research