Impact loading of a space nuclear powerplant

Preferred formulation of the problem in two space dimensions are described for solving the threefundamental equations of mechanics (conservation of mass, conservation of momentum, and conservation ofenergy). Models of the behavior of materials provide the closure to the three fundamentals equations forapplications to problems in compressible fluid flow and solid mechanics. Models of fracture and damage aredescribed. A caloric model of the equation of state is proposed to describe thermodynamic properties of solidmaterials with the phase transitions. Two-dimensional problems of a high-velocity impact of a space nuclearpropulsion system reactor are solved. High-velocity impact problems of destruction of reactor are solved for thetwo cases:1) at its crash landing on the Earth surface (the impact velocity being up to 400 m/s);2) at its impact (with velocity up to 16 km/s) with the space debris fragments

CP violation in K±→π0π0π±K^{\pm}\to\pi^0\pi^0\pi^{\pm} decay

CP violation leads to a difference between the parameters $g^+$ and $g^-$ describing the energy distributions of the charged pions produced in the $K^+ \to\pi^0 \pi^0 \pi^+$ and $K^- \to \pi^0\pi^0 \pi^-$ decays. We study the difference $(g^+ - g^-)$ as a function of the relative contributions from the QCD-penguin and the electroweak-penguin diagrams. We find that the combination of these contributions in $(g^+ - g^-)$ is very similar to the corresponding one defining the parameter $\epsilon'$ in the $K_L \to 2\pi$ decays. This observation allows a determination of the value of $(g^+ - g^-)$, using data on $\epsilon'$

Text-only domain adaptation for end-to-end ASR using integrated text-to-mel-spectrogram generator

We propose an end-to-end Automatic Speech Recognition (ASR) system that can be trained on transcribed speech data, text-only data, or a mixture of both. The proposed model uses an integrated auxiliary block for text-based training. This block combines a non-autoregressive multi-speaker text-to-mel-spectrogram generator with a GAN-based enhancer to improve the spectrogram quality. The proposed system can generate a mel-spectrogram dynamically during training. It can be used to adapt the ASR model to a new domain by using text-only data from this domain. We demonstrate that the proposed training method significantly improves ASR accuracy compared to the system trained on transcribed speech only. It also surpasses cascade TTS systems with the vocoder in the adaptation quality and training speed.Comment: Accepted to INTERSPEECH 202

Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer.

To identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Comparison of the resistance of monolithic and layered heterogeneous barriers to penetration by rigid and deformable strikers with an ogival nose based on numerical simulation

To create protective elements, information is needed on the resistance of various combinations of metal, ceramic, and heterogeneous plates, including layered ones, both in contact and with spacing. In addition, an intensive process is underway to create complex materials such as cermet composites. In this work, for verification of the code, numerical calculations of the breakdown of both monolithic and layered steel barriers by a striker with an ogival nose are performed. A series of 2D and 3D calculations for modeling the processes of penetrating heterogeneous barriers has been performed. It is shown that the resistance of heterogeneous barriers to penetration by a rigid striker is approximately the same, whereas the impact of a deformable striker on heterogeneous barriers shows that the resistance of layered barriers is lower compared to a monolithic barrier, and spacing of layers reduces the resistance of the barrier

Modelling of the processes of impact of a projectile with elements of individual defence

A two-dimensional and three-dimensional non-stationary problem of the interaction of a homogeneous impactor and a heterogeneous structure made of steel and ceramics and placed in a Kevlar pocket is considered. The model of the human body is a plate of gelatine with cylindrical inserts-imitators of human bones. The results of numerical simulation using different approaches for describing heterogeneous media are compared. On the basis of direct numerical simulation, it is shown that the gradient armor plate (steel + B4C) has the best weight and size parameters

Numerical Modelling of High-Speed Loading of Periodic Interpenetrating Heterogeneous Media with Adapted Mesostructure

A series of calculations has been conducted to study the high-speed interaction of space debris (SD) particles with screens of finite thickness. For the first time, taking into account the fracture effects, a numerical solution has been obtained for the problem of high-velocity interaction between SD particles and a volumetrically reinforced penetrating composite screen. The calculations were performed using the REACTOR 3D software package in a three-dimensional setup. To calibrate the material properties of homogeneous screens made of aluminum alloy A356, stainless steel 316L, and multilayer screens, methodical load calculations were carried out. The properties of materials have been verified based on experimental data through systematic calculations of the load on homogeneous screens made of aluminum alloy A356, stainless steel 316L, and multilayer screens comprising a combination of aluminum and steel plates. Several options for the numerical design of heterogeneous screens based on A356 and 316L were considered, including interpenetrating reinforcement with steel inclusions and a gradient distribution of steel throughout the thickness of an aluminum matrix. The study has revealed that the screens constructed as a two-layer composite of A356/316L, volumetrically reinforced composite screens, and heterogeneous screens with a direct gradient distribution of steel in the aluminum matrix provide protection for devices from both a single SD particle and streams of SD particles moving at speeds of up to 6 km/s. SD particles were modeled as spherical particles with a diameter of 1.9 mm made of the aluminum alloy Al2017-T4 with a mass of 10 mg

Моделирование процессов группового удара по гетерогенной преграде конечной толщины

Numerical simulation of the processes of high-speed loading of homogeneous and heteroge- neous targets by single projectiles, as well as by a group of projectiles with the same parameters in mass and momentum, has been carried out. Based on a comparison of the numerical simulation results for loading targets with different sets of projectiles, it is found that a projectile in the form of a ring knocks out the maximum hole in the target in terms of geometric dimensions, while a set of seven small disks removes the maximum mass from the target. The ring impact forms a continuous spall plate, which outruns the cloud of fragments of the destroyed material. Adding more than 5% of ceramics to the aluminum target volume does not allow the projectiles to penetrate throughПроведено численное моделирование процессов высокоскоростного нагружения гомогенных и гетерогенных мишеней одиночными ударниками, а также группой ударников с теми же параметрами по массе и импульсу. На основе сравнения результатов численного моделирования процессов нагружения мишеней разными наборами ударников обнаружено, что ударник в виде кольца выбивает в мишени максимальное отверстие по геометрическим размерам, тогда как набор из семи малых дисков удаляет из мишени максимальную массу, удар кольцом формирует сплошную откольную тарелочку, которая опережает в своем движении облако фрагментов разрушенного материала, внесение в алюминиевую мишень керамики более 5 % по объему не позволяет ударникам сквозного пробити