Технология сборки и сварки хребтовой балки рамы железнодорожной платформы

При производстве деталей вагонов поездов особое значение отдается технологии сборки и сварки, от которой будет зависеть качество и работоспособность конструкции. Одной из наиболее нагруженных деталей вагона является хребтовая балка. Хребтовая балка служит для крепления на ней автосцепного и тормозного оборудования. Предметом изучения является технология автоматической сварки под слоем флюса плавящимся электродом. Объектом изучения в выпускной квалификационной работе является технология изготовления хребтовой балки. Цель работы – является разработка технологического процесса сборки и автоматической сварки под слоем флюса вагонной хребтовой.In the production of train car parts, special emphasis is given to assembly and welding technology, on which the quality and performance of the structure will depend. One of the most loaded parts of the car is a spinal beam. Spinal beam serves to attach the auto-coupling and brake equipment on it. The subject of study is the technology of automatic welding under a layer of flux by a consumable electrode. The object of study in the final qualifying work is the technology of making a spinal beam. The purpose of the work is the development of the technological process of assembly and automatic welding under a layer of flux wagon spinal

Анализ термодинамических параметров нефтепровода с предварительным подогревом нефти в условиях Севера

Объектом исследования является трубопровод, на котором применяется технология перекачки нефти с предварительным подогревом. Цель работы – определить влияние термодинамических характеристик трубопроводного транспорта нефти в условиях Севера на эффективность технологии перекачки нефти с предварительным подогревом. В процессе исследования проводились гидравлические и тепловые расчеты, расчет оптимальной температуры транспорта, расчет экономической эффективности использования технологии транспорта с подогревом. Рассмотрены вопросы корректного описания вязкостно-температурной характеристики нефти для определения оптимальной температуры подогрева нефти, влияния термодинамических параметров системы «нефтепровод-окружающая среда» на эффективность применения предварительного подогрева.The object of research is the hot oil pipeline. Purpose - to determine the influence of the thermodynamic characteristics of the pipeline transport of oil in the North on the effectiveness of technology of hot oil transfer. The study carried out hydraulic and thermal calculations, the calculation of optimal transport temperature, calculation of economic efficiency of use of hot oil transport. The questions of the correct description of viscosity-temperature characteristics of the oil to determine the optimum temperature of heating oil, the effect of thermodynamic parameters of the system "pipeline-environment" on the effectiveness of transport. Presents measures for health and safety point of operation of oil heating, environmental protection, technical and economic part

Формирование проектных команд на основе анализа социальных сетей

Цель исследования – разработка социальной технологии равномерного разделения сложившегося коллектива на проектные группы. В процессе исследования проводилось разделение группы, состоящей из 20 студентов, на четыре мини-группы по 5 человек для реализации проектов, ранжирование полученных мини-групп по уровню сложности выполняемых задач и статистическая оценка эффективности разделения. В результате исследования учебная группа из 20 студентов была разделена на четыре мини-группы по 5 человек с коэффициентом модулярности кластеризации 0,284, проведено ранжирование полученных мини-групп по уровню сложности выполняемых задач, статистически оценено положительное влияние взаимодействия внутри мини-групп на индивидуальную академическую успеваемость студентов.The purpose of study is a development of social technology of uniform division of the existing staff in the project groups. During the study, there were conducted division of the group consisting of 20 students into four mini-groups of 5 people for the projects' realization, ranking of received mini-groups by the level of the task complexity to perform, and statistical evaluation of the division efficiency. As a result, the group of 20 students was divided into four mini-groups of 5 people with modularity coefficient of clustering equals to 0.284, ranking of received mini-groups by the level of the task complexity to perform was conducted, positive influence of interaction within mini-groups on individual academic performance of students was statistically estimated

Global gene flow releases invasive plants from environmental constraints on genetic diversity

When plants establish outside their native range, their ability to adapt to the new environment is influenced by both demography and dispersal. However, the relative importance of these two factors is poorly understood. To quantify the influence of demography and dispersal on patterns of genetic diversity underlying adaptation, we used data from a globally distributed demographic research network comprising 35 native and 18 nonnative populations of Plantago lanceolata. Species-specific simulation experiments showed that dispersal would dilute demographic influences on genetic diversity at local scales. Populations in the native European range had strong spatial genetic structure associated with geographic distance and precipitation seasonality. In contrast, nonnative populations had weaker spatial genetic structure that was not associated with environmental gradients but with higher within-population genetic diversity. Our findings show that dispersal caused by repeated, long-distance, human-mediated introductions has allowed invasive plant populations to overcome environmental constraints on genetic diversity, even without strong demographic changes. The impact of invasive plants may, therefore, increase with repeated introductions, highlighting the need to constrain future introductions of species even if they already exist in an area

Transcranial magnetic stimulation, synaptic plasticity and network oscillations

Transcranial magnetic stimulation (TMS) has quickly progressed from a technical curiosity to a bona-fide tool for neurological research. The impetus has been due to the promising results obtained when using TMS to uncover neural processes in normal human subjects, as well as in the treatment of intractable neurological conditions, such as stroke, chronic depression and epilepsy. The basic principle of TMS is that most neuronal axons that fall within the volume of magnetic stimulation become electrically excited, trigger action potentials and release neurotransmitter into the postsynaptic neurons. What happens afterwards remains elusive, especially in the case of repeated stimulation. Here we discuss the likelihood that certain TMS protocols produce long-term changes in cortical synapses akin to long-term potentiation and long-term depression of synaptic transmission. Beyond the synaptic effects, TMS might have consequences on other neuronal processes, such as genetic and protein regulation, and circuit-level patterns, such as network oscillations. Furthermore, TMS might have non-neuronal effects, such as changes in blood flow, which are still poorly understood

The handbook for standardised field and laboratory measurements in terrestrial climate-change experiments and observational studies

Climate change is a worldwide threat to biodiversity and ecosystem structure, functioning, and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate‐change impacts across the soil–plant–atmosphere continuum. An increasing number of climate‐change studies is creating new opportunities for meaningful and high‐quality generalisations and improved process understanding. However, significant challenges exist related to data availability and/or compatibility across studies, compromising opportunities for data re‐use, synthesis, and upscaling. Many of these challenges relate to a lack of an established “best practice” for measuring key impacts and responses. This restrains our current understanding of complex processes and mechanisms in terrestrial ecosystems related to climate change

Determination of nutrient salts by automatic methods both in seawater and brackish water: the phosphate blank

9 páginas, 2 tablas, 2 figurasThe main inconvenience in determining nutrients in seawater by automatic methods is simply solved: the preparation of a suitable blank which corrects the effect of the refractive index change on the recorded signal. Two procedures are proposed, one physical (a simple equation to estimate the effect) and the other chemical (removal of the dissolved phosphorus with ferric hydroxide).Support for this work came from CICYT (MAR88-0245 project) and Conselleria de Pesca de la Xunta de GaliciaPeer reviewe