Investigation of the skin contamination predictability by means of QForm UK extrusion code

The paper presents an innovative approach implemented in QForm UK Extrusion FEM software to analyse one of the core defects encountered in profile extrusion known as billet skin defect. The validation of the algorithm has been performed based on a number of experimental case studies taken from the literature [1,2]. Additionally, the sensitivity of the accuracy of the results to the variation in initial parameters has been analysed for both types of profile shapes: solid and hollow. Based on this, practical recommendations have been formalised for the successful industrial use of the presented algorithm

Prevalence, genetic diversity and antiretroviral drugs resistance-associated mutations among untreated HIV-1-infected pregnant women in Gabon, central Africa

BACKGROUND: In Africa, the wide genetic diversity of HIV has resulted in emergence of new strains, rapid spread of this virus in sub-Saharan populations and therefore spread of the HIV epidemic throughout the continent. METHODS: To determine the prevalence of antibodies to HIV among a high-risk population in Gabon, 1098 and 2916 samples were collected from pregnant women in 2005 and 2008, respectively. HIV genotypes were evaluated in 107 HIV-1-positive samples to determine the circulating subtypes of strains and their resistance to antiretroviral drugs (ARVs). RESULTS: The seroprevalences were 6.3% in 2005 and 6.0% in 2008. The main subtype was recombinant CRF02_AG (46.7%), followed by the subtypes A (19.6%), G (10.3%), F (4.7%), H (1.9%) and D (0.9%) and the complex recombinants CRF06_cpx (1.9%) and CRF11_cpx (1.9%); 12.1% of subtypes could not be characterized. Analysis of ARVs resistance to the protease and reverse transcriptase coding regions showed mutations associated with extensive subtype polymorphism. In the present study, the HIV strains showed reduced susceptibility to ARVs (2.8%), particularly to protease inhibitors (1.9%) and nucleoside reverse transcriptase inhibitors (0.9%). CONCLUSIONS: The evolving genetic diversity of HIV calls for continuous monitoring of its molecular epidemiology in Gabon and in other central African countries

ВПЛИВ ПЕРЕДНЬОГО НАТЯГУ НА ДЕФОРМОВАНИЙ СТАН ПРИ ПРОКАТЦІ КРУГЛИХ РОЗКАТІВ В ОВАЛЬНОМУ КАЛІБРІ

The purpose of this work is to study the effect of forward tension on the deformed state when rolling round bars in an oval caliber. The work includes experimental and theoretical parts. The experimental part of the work was done in the laboratory. Theoretical part is divided into two other parts - computer modeling and calculations using empirical formulas. The mathematical model was developed in the software package QForm 2D / 3D wich using for modeling and optimization of metal forming processes. Modeling was made for a quarter of the sample, which allowed reducing the time of task solution. Based on previous studies for the conditions of the real experiment on the contact of the sample with the rolls chose the law of friction Coulomb’s with a coefficient of friction of 0.45, most accurately corresponds to the conditions of the experiment. Other boundary conditions are selected from the standard libraries of the QForm software system according to the conditions of the real experiment. Comparison of the calculation results with the experimental data shows that the error does not exceed the engineering accuracy, that is, the process of rolling round samples in an oval caliber with a tension can be studied, based on the results of simulation in QForm. Comparison of the calculation results by the proposed formula and as a result of mathematical modeling showed that the error of determining the profile width by the empirical formula and when modeling in the software package QForm 2D / 3D are close to each other. In other words, both formula and model can be used in engineering calculations anyway. The results of theoretical and experimental studies show that under the influence of front tension reduces the value of widening when rolling round samples in oval calibers. This influence must be taken into account when calculating the deformation mode in finishing wire blocks. The results of work can be used in automated systems of modern rolling mills, which will allow to develop innovative resource-saving technologies of wire rod production on the existing equipment with lower consumption factor as compared to the existing equipment.Целью данной работы является исследование влияния переднего натяжения на деформированное состояние при прокатке круглых раскатов в овальном калибре. Работа включает экспериментальную и теоретическую части. Экспериментальная часть работы выполнена в лабораторных условиях. Теоретическая часть разделена еще на две – компьютерное моделирование и расчеты по эмпирическим формулам. Математическая модель была разработана в программном комплексе для моделирования и оптимизации процессов обработки металлов давлением QForm 2D / 3D. Моделирование проводили для четверти образца, что позволило сократить время решения задачи. На основе предыдущих исследований для условий реального эксперимента на контакте раската с валками выбрали закон трения Кулона с коэффициентом трения 0,45, наиболее точно соответствует условиям эксперимента. Другие граничные условия выбраны из стандартных библиотек программного комплекса QForm в соответствии с условиями натурного эксперимента. Сравнение результатов расчетов с экспериментальными данными показывает, что погрешность не превышает инженерную точность, то есть процесс прокатки круглых образцов в овальном калибре с натяжением можно исследовать, опираясь на результаты моделирования в QForm. Сравнение результатов расчета по предлагаемой формуле и в результате математического моделирования показали, что погрешность определения ширины профиля по эмпирической формуле и при моделировании в программном комплексе QForm 2D / 3D близки друг к другу. То есть при инженерных расчетах все равно могут быть использованы как формула, так и модель. Результаты теоретических и экспериментальных исследований показывают, что под воздействием переднего натяжения уменьшается величина уширения при прокатке круглых образцов в овальных калибрах. Это влияние необходимо учитывать при расчетах режима деформации в чистовых проволочных блоках. Результаты работы можно использовать в автоматизированных системах современных сортовых станах, что позволит разрабатывать инновационные ресурсосберегающие технологии производства катанки на существующем оборудовании с пониженным расходным коэффициентом, по сравнению с существующим.Метою даної роботи є дослідження впливу переднього натягу на деформований стан при прокатці круглих розкатів в овальному калібрі. Робота включає експериментальну та теоретичну частини. Експериментальна частина роботи виконана в лабораторних умовах. Теоретична частина поділена ще на дві – комп’ютерне моделювання та розрахунки за емпіричними формулами. Математична модель була розроблена в програмному комплексі для моделювання та оптимізації процесів обробки металів тиском QForm 2D/3D. Моделювання проводили для чверті зразка, що дозволило скоротити час на рішення задачі. На основі попередніх досліджень для умов реального експерименту на контакті розкату з валками обрали закон тертя Кулона з коефіцієнтом тертя 0,45, що найбільш точно відповідає умовам експерименту. Інші граничні умови обрані зі стандартних бібліотек програмного комплексу QForm у відповідності до умов натурного експерименту. Порівняння результатів розрахунків з експериментальними даними показує, що похибка не перевищує інженерну точність, тобто процес прокатки круглих зразків в овальному калібрі з натягом можна досліджувати, опираючись на результати моделювання в QForm. Порівняння результатів розрахунку за пропонованою формулою та в результаті математичного моделювання показали, що похибка визначення ширини профілю по емпіричній формулі та при моделюванні в програмному комплексі QForm 2D/3D близькі один до одного. Тобто при інженерних розрахунках однаково можуть бути використані як формула, так і модель. Результати теоретичних та експериментальних досліджень показують, що під впливом дії переднього натягу зменшується величина розширення при прокатці круглих зразків в овальних калібрах. Цей вплив необхідно враховувати при розрахунках режиму деформації в чистових проволочних блоках. Результати роботи можна використовувати в автоматизованих системах сучасних сортових станах, що дозволить розробляти інноваційні ресурсозберігаючі технології виробництва катанки на існуючому обладнанні зі зниженим розхідним коефіцієнтом, в порівнянні з існуючим

DEVELOPMENT AND IMPROVEMENT OF THE FORGING AND STAMPING TECHNOLOGY BY MEANS OF QFORM3D

One of the color programs for modeling of volume stamping by means of QF0RM3D is considered

Automatic Topics Identification for Reviewer Assignement

Scientific conference management involves many complex and multi-faceted activities, which would make highly desirable for the organizing people to have a Web-based management system that makes some of them a little easier to carry out. One of such activities is the assignment of submitted papers to suitable reviewers, involving the authors, the reviewers and the conference chair. Authors that submit the papers usually must fill a form with paper title, abstract and a set of conference topics that fit their submission subject. Reviewers are required to register and declare their expertise on the conference topics (among other things). Finally, the conference chair has to carry out the review assignment taking into account the information provided by both the authors (about their paper) and the reviewers (about their competencies). Thus, all this subtasks needed for the assignment are currently carried out manually by the actors. While this can be just boring in the case of authors and reviewers, in case of conference chair the task is also very complex and time-consuming. In this paper we propose the exploitation of intelligent techniques to automatically extract paper topics from their title and abstract, and the expertise of the reviewers from the titles of their publications available on the Internet. Successively, such a knowledge is exploited by an expert system able to automatically perform the assignments. The proposed methods were evaluated on a real conference dataset obtaining good results when compared to handmade ones, both in terms of quality and user-satisfaction of the assignments, and for reduction in execution time with respect to the case of humans performing the same process

Multi-class Protein Fold Recognition through a Symbolic-Statistical Framework

Protein fold recognition is an important problem in molecular biology. Machine learning symbolic approaches have been applied to automatically discover local structural signatures and relate these to the concept of fold in SCOP. However, most of these methods cannot handle uncertainty being therefore not able to solve multiple prediction problems. In this paper we present an application of the symbolic-statistical framework PRISM to a multi-class protein fold recognition problem. We compare the proposed approach to a symbolic-only technique and show that the hybrid framework outperforms the symbolic-only one in terms of predictive accuracy in the multiple prediction problem

A General Similarity Framework for Horn Clause Logic

First-Order Logic formulæ are a powerful representation formalism characterized by the use of relations, that cause serious computational problems due to the phenomenon of indeterminacy (various portions of one description are possibly mapped in different ways onto another description). Being able to identify the correct corresponding parts of two descriptions would help to tackle the problem: hence, the need for a framework for the comparison and similarity assessment. This could have many applications in Artificial Intelligence: guiding subsumption procedures and theory revision systems, implementing flexible matching, supporting instance-based learning and conceptual clustering. Unfortunately, few works on this subject are available in the literature. This paper focuses on Horn clauses, which are the basis for the Logic Programming paradigm, and proposes a novel similarity formula and evaluation criteria for identifying the descriptions components that are more similar and hence more likely to correspond to each other, based only on their syntactic structure. Experiments on real-world datasets prove the effectiveness of the proposal, and the efficiency of the corresponding implementation in the above tasks