严格依法管理污染物排放标准

本文提出了当前污染物排放标准工作中存在的问题,论述了规范污染物排放标准管理的严肃性和重要性。     

生态工业理论及其模式实现途径探讨

生态工业是一种全球新兴的工业可持续发展模式,本文着重研究、探讨了生态工业的缘起、生态工业的概念和内涵以及生态工业的理论基础,并就其实现途径提出了具体的建议。     

Detonation transition criteria from the interaction of supersonic shock-flame complexes with different shaped obstacles

The present study is an experimental investigation of the last stages of the deflagration-to-detonation transition. A fast flame following a lead shock was generated by passing a detonation wave through a perforated plate. The shock flame complex then interacts with an obstacle of different shape. We study the influence of the obstacle shape on the transition mechanism to a detonation. The obstacles studied are a single round or square obstacle, a flat plate, a C-shaped and an H-shaped obstacle. The experiments were performed in a thin transparent channel permitting high speed schlieren visualization. Stoichiometric propane-oxygen was investigated at sub-atmospheric conditions. For each obstacle configuration, the initial pressure was changed to modify the flame burning velocity and the Mach number of the leading shock. The burning velocity prior to the interaction was measured experimentally from the displacement velocity of the flame in the videos. This required estimating the speed of the gas ahead of the flame. A linear correction to the speed immediately behind the lead shock was applied using the shock change equations and the measured pressure gradient behind the lead shock in order to account for the non-steadiness of the lead shock and viscous losses to the walls. Three main findings were that the obstacle shape had a minimal influence on the critical flame strength required for transition, although obstacles with a forward facing cavity were able to suppress the transition by isolating the re-initiation event inside the cavity. The main transition mechanism for all geometries was the enhancement of the flame burning velocity through the flame interaction with the shock reflected on the obstacle leading to Richtmyer-Meshkov instability. Finally, it was found that the flame burning velocity of the initial flame required for transition was closely approximated by the Chapman-Jouguet burning velocity. Consistent with the visual observations, this supports the view that transition is favored when the flame is in phase with the acoustic waves, and strong internal pressure waves can be amplified.     

Medical referral and license disposition for drivers in Iowa

Introduction: Driver retirement and determination of fitness-to-drive are important aspects of reducing the risk of motor-vehicle collision for an older driver. A lack of information about the review process may lead to poor evaluation of drivers or an increased testing burden to referred drivers. Methods: This paper evaluates the license review process for the state of Iowa. We evaluated data from January 2014 to January 2018 and described the source of referral, testing process, and ultimate license disposition. Cox proportional hazards for competing risk were used to determine the risk of having a change in restrictions on the license and the risk of license denial. Results: 20,742 individuals were followed through the medical referral process. The most common source of referrals was licensing officials (39.7%). Drivers referred by licensing officials were less likely to be denied their license when compared to drivers from other sources (HR = 0.92 95%CI: 0.87–0.98); however, licensing official referrals were more likely to result in license restrictions compared to other sources (HR = 1.91, 95%CI: 1.82–2.00). Drivers referred by either law enforcement or a physician were more likely to ultimately have their license denied. Conclusions: Physician and law enforcement referred the drivers most likely to have their license denied. A smaller proportion of drivers were referred by physicians and law enforcement compared to licensing officials. Practical Applications: Licensing agencies should work with physicians and law enforcement to identify drivers who may need a review of their license. Comprehensive tracking of all medical referrals for a driver’s license review is important for individual states to understand the burden of their driver referral process and for identifying referral sources with a high proportion of referrals with no licensing change for targeted outreach and education.     

南水北调中线水源地汉江上游流域主要生态环境问题及对策

汉江上游是南水北调中线水源地，流域生态环境建设是保障水源地水质安全的关键。针对上游流域水环境污染、土地利用以及水土流失等重大生态环境问题，结合流域数字高程模型及水质调查对其进行了系统分析。结果表明：（1）丹江流域、库区流域及汉中盆地水质较差，CODMn和氨氮成为水源区主要污染物；（2）各子流域区植被覆盖占各自面积的712%~957%，表明流域植被覆盖较好，但沿河岸100 m范围内农业用地占292%~434%，且多为坡耕地；（3）流域水土流失严重，2000年左右流域侵蚀图显示汉江源头、秦岭南及大巴山北均出现了大片年均侵蚀模数>2 200 t/km2的区域，且有日益增强的趋势。提出加大水环境污染整治力度、加强农业用肥管理及河岸带建设、水土保持建设以及加强流域水环境及水土保持监测和科研工作等对策。     

略谈安全预案预控活动

从事故统计分析结果表明,90％以上的事故是由操作者违章作业造成的。因而提出了安全预案预控活动的有效方法,并介绍了实现这一方法的阶段及效果。     

Determinants of coverage in Community‐based Therapeutic Care programmes: towards a joint quantitative and qualitative analysis

One of the most important elements behind the success of Community‐based Therapeutic Care (CTC) programmes for the treatment of severe acute malnutrition has been their ability to achieve high levels of coverage. In CTC, coverage is measured using the Centric System Area Sampling (CSAS) method, which provides accurate and reliable estimates of programme coverage as well as information on the primary reasons for non‐attendance. Another important feature of CTC programmes is their use of socio‐cultural assessments to determine potential barriers to access and to develop context‐specific responses. By analysing data on non‐attendance provided by CSAS surveys, in conjunction with data from socio‐cultural assessments, it is possible to identify common factors responsible for failures in programme coverage. This paper focuses on an analysis of data from 12 CTC programmes across five African countries. It pinpoints three common factors (distance to sites, community awareness of the programme, and the way in which rejections are handled at the sites) that, together, account for approximately 75 per cent of non‐attendance.     

How you start matters: A comparison of Gold Fields' Tarkwa and Damang Mines and their divergent relationships with local small-scale miners in Ghana

This paper argues that actions of large-scale mining companies at the early stages of a mining project establish a legacy which sets the tone for that mine's long-term relationship with the local artisanal and small-scale mining (ASM) stakeholders. This paper compares the experiences of Gold Fields' Tarkwa and Damang mines and the divergent histories of each of these mines' relationship with local small-scale mining stakeholders. Circumstances at Damang during the discovery and early development of the project drove a rift between the mine and the ASM community. As the mine developed, a chain of ASM engagement strategies were enacted in an attempted to repair the relationship but which has never able to regain sufficient trust between the mine and ASM stakeholders. At the nearby Tarkwa mine, ASM confrontations have been much easier to manage. Despite early disagreements at Tarkwa, a relationship characterized by greater trust between the mine and ASM communities was established early and therefore ASM engagement strategies have been simpler and more effective. This paper will conclude that establishing and maintaining a positive mine legacy as early as the exploration phase of a mining project is critical to maintaining a positive, trust-based relationship between LSM companies and their local ASM stakeholders over the life of a mine.     

“Hypersensitivity to Electricity” in the Office; Symptoms and Improvement

Nineteen persons “hypersensitive” to electricity and 20 nonafflicted persons were studied for 1 ½ years. The most discernible hypersensitivity symptoms were pricking sensations and redness in the face, but these symptoms were present in only half of the afflicted. Other symptoms were similar to symptoms experienced during office work and this study does not support the idea that electrosensitivity is one single syndrome. The “hypersensitive” persons improved significantly, mainly on neuropsychiatric symptoms, but the skin problems sustained— as did the belief about their cause. The afflicted persons used less conventional medication than the group of the nonafflicted, which suggests a general tendency for attribution to environmental factors.     

A Contribution to the Study of the Antidust Respirators’ Real Performance

In most industrial enterprises, hazardous factors are present in quantities exceeding permissible levels. Such a situation requires using antidust respiratory protection. It has been suggested, however, that filters for respirators are not assessed properly and that lab results might not be related to real filtering efficiency in industry. This article contains test results of some commercially available filtering half-masks, including the effect of loading with real dust, high humidity, high temperature, and a combination of loading with dust and high humidity on the half-masks’ performance. The results show that the effect of these factors is considerable and that a combination of loading with silica dust and exposing to high humidity can cause a complete loss of performance.