旋幕式排风罩收集电焊烟尘的数值模拟

为解决电焊烟尘气流无组织排放对焊工健康和环境造成的严重影响,得出旋幕式排风罩的最佳设计参数及气流组织形式,选择GAMBIT软件建立排风罩的物理模型并进行网格划分,选用雷诺平均N-S方程(RANS)、Realizableκ-ε湍流模型及DPM离散相模型,利用Fluent计算流体力学软件对旋幕式排风罩捕集效率的相关参数进行模拟计算。结果表明:旋幕式排风罩能有效控制电焊烟尘气流的扩散;喷口角度对涡流产生的大小、位置和强度影响最大;最佳设计参数为有效吸程1. 5 m,喷口角度80°,喷口宽度14 mm;在该设计参数条件下,当罩面吸口风速为0. 3 m/s、喷口风速为1. 1m/s时,捕集效率达到最高,为98. 28%。     

相对端面比对旋风除尘器主要性能的影响

为了提高旋风除尘器的分离效率,利用RSM湍流模型构建三维旋风除尘器模型,研究了相对端面比对旋风除尘器主要性能的影响。数值模拟结果表明,随着相对端面比的减小,总压和切向速度随之降低,颗粒的停留时间缩短,因而提高了分离效率,为旋风除尘器的结构优化设计提供参考。     

Evaluating the influence of nature connection and values on conservation attitudes at a tropical deforestation frontier

Inner phenomena, such as personal motivations for pursuing sustainability, may be critical levers for improving conservation outcomes. Most conservation research and policies, however, focus on external phenomena (e.g., ecological change or economic processes). We explored the factors shaping 9 conservation attitudes toward forest and wildlife protection among colonist farmers around an Amazonian deforestation frontier. Our data comprised 241 face-to-face quantitative surveys, complemented with qualitative insights from open-ended questionnaire responses and opportunistic semistructured interviews. To account for the full spectrum of possible inner motivations, we employed measures of nature connection (indicating biospheric motivation) and personal values organized around the traditionalism (traditionalist through to high openness to change) and universalism dimensions (egoistic through to altruistic motivations). We used averaged beta-binomial generalized linear models to assess the role of external factors (socioeconomic, sociodemographic, and environmental) and personal (inner) motivations on the variation in attitudes. Each attitude was modeled separately. The relative importance of each predictor was judged by the proportion of models where it appeared as significant. Proconservation views were expressed by the majority (at least 65%) of the respondents in 7 out of the 9 attitude models. The most consistent predictors were emotional nature connection and personal values (significant in 4–6 out of 9 models), rather than external phenomena (significant in 0–5 models). However, the poorest farmers had lower scores on the agreement with prioritizing nature over development (𝛽 = –0.52, 95% CI: –0.96 to –0.07). Qualitative data also indicated that economic barriers hinder forest conservation on farms. These results suggest that biospheric, traditionalistic, and altruistic motivations promote people's proconservation attitudes, but nurturing these latent motivations is unlikely to improve conservation outcomes if material poverty remains unaddressed. Integrating the inner–outer perspective into conservation thinking and practical interventions could foster environmental stewardship and increase human well-being.     

Cyclone disaster vulnerability and response experiences in coastal Bangladesh

For generations, cyclones and tidal surges have frequently devastated lives and property in coastal and island Bangladesh. This study explores vulnerability to cyclone hazards using first‐hand coping recollections from prior to, during and after these events. Qualitative field data suggest that, beyond extreme cyclone forces, localised vulnerability is defined in terms of response processes, infrastructure, socially uneven exposure, settlement development patterns, and livelihoods. Prior to cyclones, religious activities increase and people try to save food and valuable possessions. Those in dispersed settlements who fail to reach cyclone shelters take refuge in thatched‐roof houses and big‐branch trees. However, women and children are affected more despite the modification of traditional hierarchies during cyclone periods. Instinctive survival strategies and intra‐community cooperation improve coping post cyclone. This study recommends that disaster reduction programmes encourage cyclone mitigation while being aware of localised realities, endogenous risk analyses, and coping and adaptation of affected communities (as active survivors rather than helpless victims).     

The impact of Hurricane Rita on an academic institution: lessons learned

This paper examines the impact of Hurricane Rita on one of the many universities along the Gulf Coast of the United States: Lamar University in Beaumont, Texas. Hurricane Rita, which made landfall between Sabine Pass, Texas, and Johnson's Bayou, Louisiana, on 24 September 2005, is the fourth strongest Atlantic Ocean hurricane on record and the most intense tropical cyclone ever observed in the Gulf of Mexico. This paper assesses the tasks that confronted the administration, faculty, and students of Lamar University in the days and weeks after the event. It concludes that the one factor that will influence more than any other the degree of success after any disaster is whether all levels of the administrative command institutionalise, endorse, promote, and encourage the adopted recovery plan. The research seeks to share valuable insights on the vulnerabilities that academic institutions face during natural disasters and to highlight some of the many lessons learned.     

电镀锌镍合金与热渗锌涂层热带海洋大气环境腐蚀规律对比分析

目的 解决钢铁表面金属涂层在热带海洋大气环境中易腐蚀损伤或失效的问题,选择对热带海洋大气环境耐腐蚀性能优良的金属涂层,提高钢铁工件的使用寿命。方法 在某热带海域进行户外暴露试验,对钢铁试片电镀锌镍合金和热渗锌2种金属涂层的腐蚀规律进行研究。通过扫描电镜、X射线能谱仪、光学显微镜、划格试验等,对锌镍合金镀层和热渗锌涂层的表面形貌、化学成分、截面形貌、涂层厚度及附着力等分别进行观察与测试。结果 电镀锌镍合金镀层主要发生选择性腐蚀和点蚀,在720d内具有较好的腐蚀防护性能。热渗锌层以均匀腐蚀为主,涂层微裂纹促进了腐蚀,在90 d内基体无腐蚀,360～720 d涂层的腐蚀速率较快。结论 在采用的2种金属涂层工艺中,电镀锌镍合金镀层的耐腐蚀性能远优于热渗锌涂层。相对于该热渗锌涂层,电镀锌镍合金镀层更加适合作为钢铁工件金属涂层在该海域大气环境中长期使用。     

Effects of Weed-Management Burning on Reptile Assemblages in Australian Tropical Savannas

Abstract: Fire is frequently used for land management purposes and may be crucial for effective control of invasive non‐native plants. Nevertheless, fire modifies environments and may affect nontarget native biodiversity, which can cause conflicts for conservation managers. Native Australian reptiles avoid habitat invaded by the alien plant rubber vine (Cryptostegia grandiflora) and may be susceptible to the impacts of burning, a situation that provides a model system in which to examine possible conservation trade‐offs between managing invasive plants and maintaining native biodiversity. We used replicated, experimental fire treatments (unburned, dry‐season burned, and wet‐season burned) in 2 habitats (riparian and adjacent open woodland) to examine the short‐ (within 12 months of fire) and longer‐term (within 3 years of fire) changes of reptile assemblages in response to wet‐ and dry‐season burning for weed management in tropical savannas of northern Australia. Within 12 months of fire, abundances of the skink Carlia munda (Scincidae) were higher in the burned sites, but overall reptile composition was structured by habitat type rather than by effects of burning. Within 3 years of a fire, the effects of fire were evident. Reptiles, especially the gecko Heteronotia binoei (Gekkonidae), were least abundant in dry‐season burned sites; litter‐associated species, including Carlia pectoralis (Scincidae), were rarely observed in burned habitat; and there were fewer species in the wet‐season burned sites. Reptile abundance was associated with vegetation structure, which suggests that fire‐induced changes detrimentally altered the availability of resources for some reptiles, particularly leaf‐litter species. Invasive alien plants, such as rubber vine, have severe effects on native biodiversity, and control of such species is a fundamental land management objective. Nevertheless, fire management of invasive alien plants may adversely affect native biodiversity, creating a conservation conundrum. In such scenarios, land managers will need to identify the most desired conservation goal and consider the consequences for native biota.     

西双版纳热带森林挥发性有机物的观测研究

2002年7月中旬利用异戊二烯通量测定系统对云南西双版纳热带森林异戊二烯的排放通量进行了连续测量,同时对光合有效辐射(PAR)、气温、湿度、风等参数进行了观测.结果表明,热带地区人工橡胶林区域湿季异戊二烯的排放有明显的日变化规律,中午前后为一天中的最大值,异戊二烯排放通量的日平均值在0.85～0.24mgC/(m²h)之间.对小时值和日平均值而言,异戊二烯的排放与PAR和气温的变化规律比较一致,但它对PAR比对气温更加敏感.不同的天气状况对异戊二烯的排放有非常明显的影响.橡胶林是一个单萜烯排放者,其单萜烯的排放速率明显依赖于PAR.橡胶林和热带雨林冠层上空异戊二烯和单萜烯的浓度也有明显的日变化规律,而且橡胶林区域的异戊二烯和单萜烯的浓度均明显高于热带雨林.     

超细颗粒的旋风除尘

针对细颗粒旋风除尘 ,以分子筛 空气为实验物系 ,测定了 3种不同结构的环流循环除尘系统的分离性能。实验结果表明 ,加设带有导流锥整流器的除尘系统分离效率最高 ,但压降也略有增加。由该除尘系统的粒级效率曲线可以看出 ,直径在 2 8μm左右的细颗粒由于容易被大颗粒夹带分离 ,其分离效率比 4 μm左右的颗粒高     

增江流域河流颗粒有机碳的来源、含量变化及输出通量

对华南增江径流进行了 1个水文年度的 1 5次等时段采样 ,分析了河流悬移质中主要生源元素 (C、N、H)的含量 ,并估算了不同物源的贡献 .结果表明 ,增江悬移质中的有机碳以水生藻类的贡献为主 ,土壤侵蚀来源的有机碳在悬移质粗粒组中的份额平均为 37 2 4 % ,在细粒组中仅占 1 1 1 1 % 增江流域颗粒有机碳的输出通量为 0 83× 1 0 6g·km-2 ·a-1 ,其中来自土壤的颗粒有机碳通量为 0 2 2× 1 0 6g·km-2 ·a-1 .