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The object of research is the complex realm of energy localization and coherent ballistic electronic transport within low-dimensional silicon quantum wires, specifically those doped with germanium atoms. Unlike their three-dimensional counterparts, low-dimensional systems exhibit unique electronic transport behaviors, necessitating novel analytical approaches for a comprehensive understanding. The core of this investigation leverages the Phase Field Matching Theory (PMFT) and the tight-binding (TB) approximation, sophisticated methodologies that enable a deep dive into the quantum mechanical nuances of these systems. Through this lens, we examine the intricate dynamics of dispersion relationships, phase factors, group velocities, and notably, the impact of defects introduced by the germanium doping. This research meticulously analyzes how these defects affect electronic and thermal conductivities, along with densities of states, offering new insights into the role of Fano resonances in the fluctuation of transmission and reflection spectra. These resonances, we find, are crucially dependent on the nature of the defects, their configuration, and the electronic parameters in their vicinity, underscoring the nuanced interplay between material composition and electronic properties in low-dimensional systems. The implications of our findings extend far beyond the theoretical. They pave the way for significant advancements in nanotechnology and the design of electronic devices, highlighting the potential for creating more efficient, high-performance components. Furthermore, this work proposes a framework for developing non-destructive testing methodologies that could revolutionize material science by enabling the precise analysis of defects in low-dimensional systems without causing damage. This is particularly critical for the ongoing development of materials with optimized properties for various applications, from electronics to energy storage. In essence, this research not only enriches our understanding of the physics governing low-dimensional systems but also offers practical insights into leveraging these properties for technological innovation. By bridging the gap between theoretical physics and material science, our study sets the stage for the next generation of electronic components and non-destructive evaluation techniques, marking a significant step forward in the application of quantum mechanics to real-world challenges. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effect of 4-week unknown vs known loads strength training intervention on power output performance and throwing velocity in junior team handball players. Methods: Twenty-eight junior team-handball players (17.2 ± 0.6 years, 1.79 ± 0.07 m, 75.6 ± 9.4 kg)were divided into two groups (unknown loads: UL; known loads: KL). Both groups performed two sessions weekly consisting of four sets of six repetitions of the bench press throw exercise, using the 30%, 50% and 70% of subjects’ individual 1 repetition maximum (1RM). In each set, two repetitions with each load were performed, but the order of the loads was randomised. In the KL group, researchers told the subjects the load to mobilise prior each repetition, while in the UL group, researchers did not provide any information. Maximal dynamic strength (1RM bench press), power output (with 30, 50 and 70% of 1RM) and throwing velocity (7 m standing throw and 9 m jumping throw) were assessed pre- and post-training intervention. Results: Both UL and KL group improved similarly their 1RM bench press as well as mean and peak power with all loads. There were significant improvements in power developed in all the early time intervals measured (150 ms) with the three loads (30, 50, 70% 1RM) in the UL group, while KL only improved with 30% 1RM (all the time intervals) and with 70% 1RM (at certain time intervals). Only the UL group improved throwing velocity in both standing (4.7%) and jumping (5.3%) throw (p > 0.05). Conclusions: The use of unknown loads has led to greater gains in power output in the early time intervals as well as to increases in throwing velocity compared with known loads. Therefore unknown loads are of significant practical use to increase both strength and in-field performance in a short period of training. [ABSTRACT FROM AUTHOR]

Background: Lead-free hunting bullets are an alternative to lead-containing bullets which cause health risks for humans and endangered scavenging raptors through lead ingestion. However, doubts concerning the effectiveness of lead-free hunting bullets hinder the wide-spread acceptance in the hunting and wildlife management community. Methods: We performed terminal ballistic experiments under standardized conditions with ballistic soap as surrogate for game animal tissue to characterize dimensionally stable, partially fragmenting, and deforming lead-free bullets and one commonly used lead-containing bullet. The permanent cavities created in soap blocks are used as a measure for the potential wound damage. The soap blocks were imaged using computed tomography to assess the volume and shape of the cavity and the number of fragments. Shots were performed at different impact speeds, covering a realistic shooting range. Using 3D image segmentation, cavity volume, metal fragment count, deflection angle, and depth of maximum damage were determined. Shots were repeated to investigate the reproducibility of ballistic soap experiments. Results: All bullets showed an increasing cavity volume with increasing deposited energy. The dimensionally stable and fragmenting lead-free bullets achieved a constant conversion ratio while the deforming copper and lead-containing bullets showed a ratio, which increases linearly with the total deposited energy. The lead-containing bullet created hundreds of fragments and significantly more fragments than the lead-free bullets. The deflection angle was significantly higher for the dimensionally stable bullet due to its tumbling behavior and was similarly low for the other bullets. The deforming bullets achieved higher reproducibility than the fragmenting and dimensionally stable bullets. Conclusion: The deforming lead-free bullet closely resembled the deforming lead-containing bullet in terms of energy conversion, deflection angle, cavity shape, and reproducibility, showing that similar terminal ballistic behavior can be achieved. Furthermore, the volumetric image processing allowed superior analysis compared to methods that involve cutting of the soap blocks. [ABSTRACT FROM AUTHOR]

Over last few decades, Al-based metal matrix composites (MMCs) have become a promising material of choice for lightweight armors in vehicles. Recent development in ultra-fine-grain and nanostructured material technology provides a new opportunity for the substantial strength enhancement of MMCs unattainable with the conventional microstructure of microscale, leading to significant weight reduction in armor packages. In this article, we will present the latest development of a novel class of nanostructured metal matrix composites (NMMCs) based on submicron SiC particulates reinforced nanocrystalline Al alloys. The successful fabrication of large-dimension NMMCs plates with a cost-effective synthesis and consolidation process that can be scaled up for mass production will be demonstrated. The microstructure, processing, mechanical properties, and their correlations of this class of NMMCs will also be reported. The ballistic performance of the NMMCs is investigated through a real test of high-speed machinegun bullets, and a numerical modeling as well. [ABSTRACT FROM AUTHOR]

In the present work, a ballistic material-model development approach is combined with transient non-linear dynamics simulations of the projectile/armour interactions to explore the armour-hard-facing potential of multi-walled carbon nanotube (MWCNT) reinforced, poly-vinyl-ester-epoxy (PVEE)-matrix composite mats. This approach is applied to improving the ballistic-protection performance of E-glass fibre-mat reinforced PVEE-matrix laminate armour. Two different architectures of the MWCNT-reinforced/PVEE-matrix composite mats were considered: (a) a MWCNT-ply mat structure in which the MWCNT reinforcements are aligned parallel to the armour faces and (b) a MWCNT-forest mat structure in which the MWCNT reinforcements are aligned orthogonally to the armour faces. The projectile/armour interaction simulation results showed that, at low volume fractions of MWCNTs, both armour architectures yield no discernable increase in the armour ballistic-protection performance as measured by the armour. On the other hand, at high MWCNT volume fractions of MWCNTs, the first armour architecture remained ineffective whereas the second showed a minor improvement in the ballistic-protection performance relative to the corresponding monolithic armour. These results were rationalized using published experimental observations pertaining to the effect of MWCNTs on the in-plane and the through-the-thickness properties of fibre-mat/polymer-matrix composite materials. [ABSTRACT FROM AUTHOR]

Abstract: The present paper examines the high-velocity impact behaviour of agglomerated cork-cored structures. The ballistic performance was studied by impact-perforation tests. Three different types of specimens were tested: an agglomerated cork, two spaced thin aluminium plates, and a pair of thin aluminium plates separated by an agglomerated-cork core. The behaviour of the agglomerated cork and the effects of the cork core were analysed in terms of the ballistic limit, residual velocity, and energy absorption. The ballistic limit of cork-cored structures increased slightly, whereas the absorbed energy was strongly augmented by the presence of the cork core. [Copyright &y& Elsevier]