Pulse-periodic laser action to create an ordered heterogeneous structure based on copper and zinc oxides

Разработан метод импульсно-периодического лазерного воздействия для создания упорядоченной гетерогенной структуры CuO / ZnO. Осуществлялось импульсно-периодическое воздействие излучением CO2-слэб лазера ROFIN DC 010 на два типа образцов из латуни Л62: шлифованные и подвергнутые поверхностному травлению после шлифовки. Установлено, что при повышении мощности излучения в диапазоне 270...330 Вт плотность нановолокон возрастала, формировались более короткие и широкие нановолокна. Синтезированные нановолокна, укрепленные на подложке, имели длину ~0,5...3 мкм, диаметр ~40...90 нм. Поверхность Cu-Zn сплава, подвергнутая травлению имела четко различимую межзеренную границу с размером зерен в диапазоне ~40...100 мкм. Поверхность образцов после травления состояла из чистой меди. В результате оксидирования на границах зерен, размер которых уменьшается до ~20...30 мкм, наблюдался рост нановолокон ZnO. При увеличении времени оксидирования лазерным воздействием на воздухе, рост нановолокон ZnO становился более интенсивным. A method of pulse-periodic laser action has been developed to create an ordered heterogeneous structure of CuO / ZnO. The pulse-periodic irradiation of a CO2 slab ROFIN DC 010 laser into two types of brass samples L62: ground and surface etched after grinding was performed. It was found that when the beam power was increased in the range 270–330 W, the density of nanowires increased, shorter and wider nanowires formed. The synthesized nanowires reinforced on the substrate had a length of ~ 0.5–3 μm, a diameter of ~ 40–90 nm. The surface of the Cu-Zn alloy subjected to etching had a clearly discernable grain boundary with a grain size in the range of ~ 40–100 μm. The surface of the samples after etching consisted of pure copper. As a result of oxidation at the grain boundaries, whose size decreases to ~ 20–30 μm, growth of ZnO nanowires was observed. With an increase in the time of oxidation by laser exposure to air, the growth of ZnO nanowires became more intense

Chemical contaminants in juvenile gray whales (\u3ci\u3eEschrichtius robustus\u3c/i\u3e) from a subsistence harvest in Arctic feeding grounds

Gray whales are coastal migratory baleen whales that are benthic feeders. Most of their feeding takes place in the northern Pacific Ocean with opportunistic feeding taking place during their migrations and residence on the breeding grounds. The concentrations of organochlorines and trace elements were determined in tissues and stomach contents of juvenile gray whales that were taken on their Arctic feeding grounds in the western Bering Sea during a Russian subsistence harvest. These concentrations were compared to previously published data for contaminants in gray whales that stranded along the west coast of the US during their northbound migration. Feeding in coastal waters during their migrations may present a risk of exposure to toxic chemicals in some regions. The mean concentration (standard error of the mean, SEM) of Σ PCBs [1400 (130) ng/g, lipid weight] in the blubber of juvenile subsistence whales was significantly lower than the mean level [27 000 (11 000) ng/g, lipid weight] reported previously in juvenile gray whales that stranded in waters off the west coast of the US. Aluminum in stomach contents of the subsistence whales was high compared to other marine mammal species, which is consistent with the ingestion of sediment during feeding. Furthermore, the concentrations of potentially toxic chemicals in tissues were relatively low when compared to the concentrations in tissues of other marine mammals feeding at higher trophic levels. These chemical contaminant data for the subsistence gray whales substantially increase the information available for presumably healthy animals

АНАЛИЗ ЭФФЕКТИВНОСТИ ПРИМЕНЕНИЯ ГИДРОПРИВОДА ШТАНГОВОГО СКВАЖИННОГО НАСОСА "ГЕРОН" В КАЧЕСТВЕ АЛЬТЕРНАТИВЫ СТАНКУ-КАЧАЛКЕ

The work is devoted to the analysis of the effectiveness of the replacement of pumpjacks for modern hydraulic drives of the “Geron” type, as well as to an overview of these drives. The results of field tests of real companies were used as initial data. Energy efficiency and ease of maintenance achieved in Heron hydraulic drives through the introduction of an intelligent electronic control system were decisive criterias of the comparison. As a result of the work carried out, conclusions about the profitability of replacing pumpjacks with hydraulic drives “Geron” were drawn.Работа посвящена анализу эффективности замены станковкачалок на современные гидравлические приводы типа «Герон», а также обзору этих приводов. В качестве исходных данных использовались результаты промысловых испытаний реальных компаний. Важными критериями сравнения были энергоэффективность и простота обслуживания, достигаемые в гидравлических приводах «Герон» за счёт внедрения электронной системы управления. В результате проведённой работы были сделаны выводы о рентабельности замены станков качалок на гидравлические приводы «Герон»

Exchanging traditional pumping unit for a "geron" hydraulic drive

This work was devoted to analysis of the efficiency of the application of a "Geron" hydraulic drive as an alternative to a beam pumping unit. The issue of replacement old drives for new one was considered in the context of economic profitableness taking into account field conditions of Russia and neighbor countries. To prepare this scientific article, different data about field experience of usage the machines in different countries and fields were asked for and obtained. Thanks to information got general characteristics of both machines with their advantages and disadvantages based generally on technological, energetical and economic data were composed. After this the drives were compared with each other. As a result, hydraulic drive "Geron" was taken to be a good alternative of traditional pumping unit. © Published under licence by IOP Publishing Ltd