Thermal stability of a laser-clad NiCrBSi coating hardened by frictional finishing

Frictional treatment decreases surface roughness of a NiCrBSi laser coating and increases its microhardness and abrasive wear resistance. Even after softening annealing at 900 °C, the coating subjected to frictional treatment preserves its advantage in hardness and wear resistance over the original clad coating. Annealing at 1000 °C after frictional treatment ensures less effective growth of the hardness and wear resistance of the coating as compared to annealing of the undeformed coating due to the limited precipitation of large Cr23C6 carbides on the deformed surface, which form a wear-resistant framework. © 2017 Author(s).Russian Foundation for Basic Research, RFBR: 16-38-00452-mol-a01201375904108692015Federal Agency for Scientific Organizations: 01201463331Federal Agency for Scientific OrganizationsUral Branch, Russian Academy of Sciences, UB RAS: 15-9-12-45The study was financially supported by the Russian Foundation for Basic Research (RFBR), grant No. 16-38-00452-mol-a, by the Foundation for Assistance to Small Innovative Enterprises (FASIE), project UMNIK No. 108692015; the work was done within the Complex Program of UB RAS, project No. 15-9-12-45, within the state order for IES UB RAS, No. 01201375904 and within the state order of The Federal Agency for Scientific Organizations (FASO Russia) on the subject “Structure”, No. 01201463331. The experimental research was done on the equipment installed at the Plastometriya Collective Use Center of IES UB RAS

METHODOLOGICAL APPROACHES TO EVALUATING BEER AND NON-ALCOHOLIC PRODUCTS SHELF LIFE

The article discusses the relevance of developing methodological approaches to the beer and soft drinks accelerated aging method in the market. The controlled indicators selection principles, mainly affecting the quality of the finished product, and the basic equation describing the dependence of changes in indicators on the main temperature factor are given. Studies of the influence of various physical factors (temperatures in the range of 50–60 °C, UV-radiation), both individually and jointly, on the physicochemical and organoleptic characteristics of packaged water for various experimental versions did not show statistically significant changes in the normalized parameters of the basic salt and microelement composition investigated water during storage. The optimal mode of accelerated «aging» of packaged water at an elevated temperature (up to 60 °C) and UV-radiation was established. In the case of soft drinks, thermostating was used when changing the temperature regimes (heat 50 ± 2 °C / cold 6 ± 2 °C) at an exposure time of 30 days, which made it possible to observe a decrease in taste and aroma compared with the control, as well as a decrease in sweetness and the appearance of a slight plastic taste for non-carbonated drink. The influence a temperature regime change on brewing products, which cannot be estimated using the existing method due to the high turbidity, is shown.The article discusses the relevance of developing methodological approaches to the beer and soft drinks accelerated aging method in the market. The controlled indicators selection principles, mainly affecting the quality of the finished product, and the basic equation describing the dependence of changes in indicators on the main temperature factor are given. Studies of the influence of various physical factors (temperatures in the range of 50–60 °C, UV-radiation), both individually and jointly, on the physicochemical and organoleptic characteristics of packaged water for various experimental versions did not show statistically significant changes in the normalized parameters of the basic salt and microelement composition investigated water during storage. The optimal mode of accelerated «aging» of packaged water at an elevated temperature (up to 60 °C) and UV-radiation was established. In the case of soft drinks, thermostating was used when changing the temperature regimes (heat 50 ± 2 °C / cold 6 ± 2 °C) at an exposure time of 30 days, which made it possible to observe a decrease in taste and aroma compared with the control, as well as a decrease in sweetness and the appearance of a slight plastic taste for non-carbonated drink. The influence a temperature regime change on brewing products, which cannot be estimated using the existing method due to the high turbidity, is shown

Сравнительные аналитические характеристики поликапиллярных хроматографических колонок с различным диаметром капилляров

Straight gas chromatography multicapillary columns (MCC) with 40 µm diameter capillaries (hereafter – 40 µm MCC) have been known for quite a long time and are well studied; they are used in portable gas analyzers. Some chromatographic characteristics of 25 µm MCCs, which appeared relatively recently, were also studied, while commercially available 60 and 80 µm MCCs are poorly studied. In this work the main analytical characteristics of 60 and 80 µm MCCs were determined and compared with the characteristics of 25 and 40 µm MCCs. It was shown that the maximum specific efficiency of the columns decreased with increasing column capillary diameter and is approximately 24.8, 18.2, 13.7 and 9.5 thousand theoretical plates (t.p.) per meter for 25, 40, 60 and 80 µm MCCs, respectively. It was established that the height equivalent to a theoretical plate of 60 and 80 μm MCCs was not varied significantly over a wide range of carrier gas velocities (nitrogen and helium), which allowed operating MCCs at high carrier gas flows essentially without loss of their efficiency. Moreover, for all MCCs the separation rate for peaks with a retention factor over 10 exceeded 600 t.p./s, and for peaks with a lower retention factor could be several thousand t.p./s, which is significantly higher than for conventional capillary and packed columns. It was established that it was possible to create very high carrier gas flows (up to 1000 cm3/min or more) for 60 µm MCCs and especially 80 µm MCCs at a relatively low pressure drop across the column. Therefore they can work as a part of chromatographic systems that require high carrier gas flow.Keywords: fast gas chromatography, multicapillary column, column efficiency, column height equivalent to the theoretical plate, separation rate, carrier gas velocity, carrier gas pressure.Прямые газохроматографические поликапиллярные колонки (ПКК) с капиллярами диаметром 40 мкм (далее ПКК 40 мкм) известны достаточно давно и хорошо изучены, они находят применение в составе портативных газоанализаторов. Исследованы также некоторые хроматографические характеристики появившихся относительно недавно ПКК 25 мкм, между тем коммерчески доступные ПКК 60 и 80 мкм малоизучены. В данной работе определены основные аналитические характеристики ПКК 60 и 80 мкм и проведено их сравнение с характеристиками ПКК 25 и 40 мкм. Показано, что максимальная удельная эффективность колонок уменьшается с увеличением диаметра капилляров колонок и составляет примерно 24.8, 18.2, 13.7 и 9.5 тысяч теоретических тарелок (т.т.) на метр длины для ПКК 25, 40, 60 и 80 мкм соответственно. Установлено, что высота, эквивалентная т.т., ПКК 60 и 80 мкм не сильно изменяется в широком интервале скоростей газа-носителя (азот и гелий), что позволяет эксплуатировать ПКК при высоких потоках газа-носителя без существенной потери их эффективности. При этом для всех ПКК скорость разделения для пиков с фактором удерживания более 10 превышает 600 т.т./с, а для пиков с меньшим фактором удерживания может составлять несколько тысяч т.т./с, что значительно выше, чем для обычных капиллярных и наполненных колонок. Установлено, что для ПКК 60 мкм и особенно ПКК 80 мкм возможно создание очень высоких потоков газа-носителя (до 1000 см3/мин и более) при относительно низком перепаде давлений на колонке. Поэтому они могут работать в составе хроматографических систем, требующих высокий поток газа-носителя.Ключевые слова: скоростная газовая хроматография, поликапиллярные колонки, высота, эквивалентная теоретической тарелке, скорость разделения, эффективность колонки, скорость газа-носителя, давление газа-носителя