Dialdehyde starch and zein plastic: Mechanical properties and biodegradability

Dialdehyde starch (DAS) and zein, a hydrophobic corn protein, were investigated to produce biodegradable plastics with improved water resistance and mechanical properties. In the study, dialdehyde starch and zein ratio, plasticizers, and degree of starch oxidation were examined. Increased molding temperature and level of starch oxidation decreased water absorption of the plastic. Tensile strength and Young's modulus increased with starch oxidation. The biodegradation of starting materials and ground plastic specimens was studied in aerobic soil reactors maintained at 25°C for 180 days. Biodegradation of corn starch, zein, and dialdehyde starch for 180 days produced CO₂ equivalent to 64, 63, and 10% of theoretical carbon, respectively. Specimens of molded DAS and zein (3 : 1) plastic showed accelerated CO₂ evolution compared to DAS and other raw materials alone. By 180 days, specimens made with starch of low oxidation (1 and 5% oxidized) demonstrated a 60% biodegradation, and specimens with highly oxidized starch (90% oxidized) achieved 37% biodegradation.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.Journal Paper J-15927 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Project No. 3258.     

民航与环境

国际民航组织(ICAO)理事会的航空环境保护委员会(cAEP)提出了与民航有关的主要的环境问题:飞机噪音和来自飞机发动机的排放.在源头减少飞机的噪音是CAEP的工作重点,但是消除噪声和土地利用计划也受到相当大的注意.有关排放的工作可分为三类:技术和标准、管理措施和基于市场的机制.国际民航组织通过技术合作和培训计划给一些国家提供与环境有关的帮助.     

An empirical investigation of construction and demolition waste generation rates in Shenzhen city, South China

The construction and demolition waste generation rates (C&D WGRs) is an important factor in decision-making and management of material waste in any construction site. The present study investigated WGRs by conducting on-site waste sorting and weighing in four ongoing construction projects in Shenzhen city of South China. The results revealed that WGRs ranged from 3.275 to 8.791 kg/m² and miscellaneous waste, timber for formwork and falsework, and concrete were the three largest components amongst the generated waste. Based on the WGRs derived from the research, the paper also discussed the main causes of waste in the construction industry and attempted to connect waste generation with specific construction practices. It was recommended that measures mainly including performing waste sorting at source, employing skilful workers, uploading and storing materials properly, promoting waste management capacity, replacing current timber formwork with metal formwork and launching an incentive reward program to encourage waste reduction could be potential solutions to reducing current WGRs in Shenzhen. Although these results were derived from a relatively small sample and so cannot justifiably be generalized, they do however add to the body of knowledge that is currently available for understanding the status of the art of C&D waste management in China.     

'It'll never happen to me': understanding public awareness of local flood risk

Following the severe flood events of 1998 and 2000, the United Kingdom's Environment Agency prioritised the need to increase public flood risk awareness. Drawing on data collected during research undertaken for the Environment Agency, this paper contributes to understanding of one aspect of flood awareness: people's recognition that their property is in an area that is potentially at risk of flooding. Quantitative analyses indicate that class is the most influential factor in predicting flood risk awareness, followed by flood experience and length of time in residence. There are also significant area differences. Our qualitative work explores how those defined as 'at risk' account for their lack of awareness or concern about their risk status. We conclude that the problem is often not simply a lack of awareness, but rather, assessments of local risk based on experience that underestimate the impact of rare or extreme events. We underline the importance of engaging with local perspectives on risk and making local people part of 'awareness-raising' processes.     

First-trimester screening: dealing with the fall-out

The articles collected together in this issue describe first-trimester screening for a variety of complications. With the advance of both technology and research, early pregnancy screening is becoming ever more sophisticated and complex. While there are clear benefits to most women receiving early reassurance that their baby is developing as expected, there is no evidence to suggest that an earlier prenatal diagnosis has less long-term emotional impact than at later gestations. The poignancy of ultrasound images for many parents means that it can be especially difficult to manage the anxiety when an ultrasound marker is highlighted as potential cause for concern. They can then face a journey of anxiety-laden uncertainty, which can extend through much of the pregnancy, and even beyond. Professionals involved in screening need to recognise and acknowledge such adverse side-effects and develop the skills necessary to help parents understand and cope with the uncertainties inherent in the process. Copyright © 2011 John Wiley & Sons, Ltd.     

Syndromic associations with congenital anomalies of the fetal thorax and abdomen

Anomalies of the thorax and abdomen can be found in a number of genetic syndromes. Whilst it may not be possible to make a definitive diagnosis before birth, knowledge of the potential associations can be useful for the prenatal diagnostician when examining the fetus and counselling the parents. In this article, we describe conditions where other features may be detectable using prenatal ultrasound. We describe the features, potential diagnostic aids and prognosis. The tables list other potential features that may be identified. The range of conditions that can occur emphasises the value of genetic input in the management of a fetus with an apparently normal karyotype and multiple anomalies, the need to save material for future molecular analysis and the requirement of a detailed examination after delivery. These are needed in order to make accurate diagnoses and advise parents with regard to recurrence risks and the potential for prenatal diagnosis in future pregnancies. Copyright © 2008 John Wiley & Sons, Ltd.     

A Lifecycle Assessment and Economic Valuation of Recycling

The financial costs of recycling schemes fail to account for external costs and benefits such as environmental pollution, road congestion and accidents. This paper compares the environmental and social impacts of a kerbside collection scheme for recyclable household waste, with a bring scheme, using lifecycle assessment. Economic valuation is used to assign relative weights to these impacts. A second comparison examines the relative external costs of recycling and landfill disposal of waste. The results show that the kerbside collection scheme has a lower external cost than the bring scheme, but this is of less importance than the benefits to be gained within the manufacturing system by using secondary materials. It is concluded that the combination of lifecycle assessment and economic valuation is an effective means of evaluation to direct the sustainable development of waste management.     

“Killing them with kindness”? A study of service employees' responses to uncivil customers

Experiencing uncivil customers is a frequent reality for many people working in the service industry. Past research has established that dealing with uncivil customers can be distressing for employees and can sometimes lead them to engage in reciprocal, discourteous behavior. The purpose of our research is to delve deeper into the experience of customer incivility from the perspective of service employees in order to better understand the various ways in which they respond to customer incivility. We conducted 64 interviews with service employees across an array of occupations and developed a typology of responses to customer incivility. These responses fell into four categories based on the extent to which service employees' actions were intended to promote social harmony (and therefore could broadly be considered civil or uncivil), as well as their perceived agency in the situation. We describe how each response was associated with different interpersonal and intrapersonal consequences and explain the implications of our typology for management theory and practice.     

How do I like thee? Let me appraise the ways

This study examined the effect of leader-member exchange (LMX) on the relationship between employee performance (measured objectively) and the supervisor's rating of that performance. To date, no field study has tested whether high and low LMX members receive differential ratings based on their LMX relationship, beyond their actual performance. Data were collected from employees (directory assistants, cable technicians, and dispatch clerks) and their supervisors in a telephone company. The objective measures of performance which were available for these jobs were related to supervisory ratings of performance for high and low LMX employees. The results showed that poorly performing high LMX employees were given high performance ratings, regardless of their actual performance. The ratings of low LMX employees were consistent with their actual performance. The effect of LMX was more pronounced with more general task and relationship rating categories. Alternative explanations of the results, as well as the theoretical and practical implications for performance appraisal and LMX research, were discussed.