Health risk modifiers of exposure to persistent pollutants among indigenous peoples of Chukotka

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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Features of additive technologies implementation in aerospace equipment production

Additive technologies (AT) are effective when processing relatively small batches of products, when high costs of materials is compensated by lowering fixed costs which are related to the use of traditional technologies. Aerospace equipment production is characterized, as a rule, within single and serial (small and medium series) types of production, which is why additive technologies will be in high demand in this field of engineering production. There is a necessary condition, regarding the widespread implementation and spreading of new technologies. It is its technical and economic efficiency. This article provides specific information on the comparative characteristics of classic and additive technologies of the common purpose and some pros and cons of these technologies. The main disadvantage of layer-by-layer synthesis of complexly shaped products is a relatively long duration of machine processing, resulting in high production costs, depreciation of equipment, and calculation of net costs. It is also noted that the feasibility study of AT use leads to reducing the number of workers and costs for maintaining on-site life safety. Also the usage of AT will lead to the reduction of shop and factory overhead costs due to cheaper logistics. In the field of aerospace engineering the major and promising direction of work in the field of additive manufacturing is to improve the technologies and equipment for the synthesis of products of ceramic and composite materials

Features of additive technologies implementation in aerospace equipment production

Additive technologies (AT) are effective when processing relatively small batches of products, when high costs of materials is compensated by lowering fixed costs which are related to the use of traditional technologies. Aerospace equipment production is characterized, as a rule, within single and serial (small and medium series) types of production, which is why additive technologies will be in high demand in this field of engineering production. There is a necessary condition, regarding the widespread implementation and spreading of new technologies. It is its technical and economic efficiency. This article provides specific information on the comparative characteristics of classic and additive technologies of the common purpose and some pros and cons of these technologies. The main disadvantage of layer-by-layer synthesis of complexly shaped products is a relatively long duration of machine processing, resulting in high production costs, depreciation of equipment, and calculation of net costs. It is also noted that the feasibility study of AT use leads to reducing the number of workers and costs for maintaining on-site life safety. Also the usage of AT will lead to the reduction of shop and factory overhead costs due to cheaper logistics. In the field of aerospace engineering the major and promising direction of work in the field of additive manufacturing is to improve the technologies and equipment for the synthesis of products of ceramic and composite materials

First Calibrated Methane Bubble Wintertime Observations in the Siberian Arctic Seas: Selected Results from the Fast Ice

This paper presents the results of an acoustic survey carried out from the fast ice in the shallow waters of the East Siberian Arctic Shelf (ESAS) using a single beam echosounder. The aim of this paper is to demonstrate an improved approach to study seafloor seepages in the Arctic coastal zone with an echosounder calibrated on site. During wintertime field observations of natural rising gas bubbles, we recorded three periods of their increased activity with a total of 63 short-term ejections of bubbles from the seabed. This study presents quantitative estimates of the methane (CH4) flux obtained in wintertime at two levels of the water column: (1) at the bottom/water interface and (2) at the water/sea ice interface. In winter, the flux of CH4 transported by rising bubbles to the bottom water in the shallow part of the ESAS was estimated at ~19 g·m−2 per day, while the flux reaching the water/sea ice interface was calculated as ~15 g·m−2 per day taking into account the diffusion of CH4 in the surrounding water and the enrichment of rising bubbles with nitrogen and oxygen. We suggest that this bubble-transported CH4 flux reaching the water /sea ice interface can be emitted into the atmosphere through numerous ice trenches, leads, and polynyas. This CH4 ebullition value detected at the water/sea ice interface is in the mid high range of CH4 ebullition value estimated for the entire ESAS, and two orders higher than the upper range of CH4 ebullition from the northern thermocarst lakes, which are considered as a significant source to the atmospheric methane budget

Health risk modifiers of exposure to persistent pollutants among indigenous peoples of Chukotka

The aim of the study was to assess temporal trends in health risks related to most common persistent contaminants, including polychlorinated biphenyls (PCBs), dichloro-diphenyl-trichloroethanes (DDTs), lead (Pb), as well as mercury (Hg) among indigenous peoples living in coastal areas of Chukotka in Arctic Russia. This is examined in relation to exposure pathways and a range of social and behavioral factors capable of modifying the exposure to these contaminants, including place of residence, income, traditional subsistence, alcohol consumption, and awareness of risk prevention. The primary exposure pathway for PCBs is shown to be the intake of traditional foods, which explained as much as 90% of the total health risk calculated employing established risk guidelines. Nearly 50% of past DDT-related health risks also appear to have been contributed by contaminated indoor surfaces involving commonly used DDT-containing insecticides. Individuals who practiced traditional activities are shown to have experienced a 4.4-fold higher risk of exposure to PCBs and a 1.3-fold higher risk for DDTs, Pb, and Hg. Low income, high consumption of marine mammal fat, alcohol consumption, and lack of awareness of health risk prevention are attributed to a further 2- to 6-fold increase in the risk of PCBs exposure. Low socioeconomic status enhances the health risks associated with exposure to the persistent contaminants examined