Influence of environmental street characteristics on walking route choice of elderly people

Walking is an important source of outdoor physical activity among elderly people. In order to devise measures aimed at encouraging walking among the elderly it is important to understand how the local environment influences the walking behaviour of elderly people. Here, a model describing the influence of environmental street characteristics on the walking route choice of elderly people is presented. Techniques adapted from the field of transportation research were employed within the model. Data concerning the walking route choice to specific destinations reported by 364 independently living elderly residents (55–80 years) from three Dutch urban districts were collected. Route choice was modelled within a ‘Geographic Information System’ (GIS) database by using ‘resistance factors’ to describe the resistance to walking of street sections (i.e. links) within the street network. These factors were optimized by minimizing the difference between the estimated and the reported number of trips along each link. This is, to the authors' knowledge the first time that this technique has been applied within this context. The influence of link characteristics on link resistance was investigated by multivariate linear regression. The first results of the route choice model and the influence of street characteristics on route choice are reported and discussed.     

UTILIZATION OF AGRICULTURAL WASTE CORN COB FOR THE PREPARATION OF CARBON ADSORBENT

In the present study, a series of activated carbons were prepared from agricultural waste corn cob by chemical and physical activations with potassium hydroxide (KOH)/potassium carbonate (K₂CO₃) and carbon dioxide (CO₂). The effect of process variables such as impregnation ratio, impregnation time, activation temperature and soaking time of CO₂ was studied in order to relate these preparation parameters with the physical properties of final carbon products. The resulting activated carbons were characterized by nitrogen adsorption[ch-[chdesorption isotherms at 77 K. The surface areas and pore volumes of carbons were estimated by the BET equation, the Langmuir equation and the t-plot method. Under the experimental conditions investigated, the main parameters in the activation of corn cob were found to be the impregnation ratio and activation temperature. The soaking time of CO₂ is another important variable, which had a strong effect on the pore volume development. The BET surface area and total pore volume were as large as about 2000 m²/g and about 1.0 cm³/g, respectively. This study showed that the activation of agricultural waste corn cob with KOH/K₂CO₃ and CO₂ was suitable for the preparation of large-surface-area activated carbons.     

Assessment of pesticide availability in soil fractions after the incorporation of winery-distillery vermicomposts

The influence of two vermicomposts from winery and distillery wastes on the distribution of diuron in agricultural soil was studied. Physical soil fractionations at 0, 9, 27, 49 and 77 days, allowed the quantification of pesticide residues in different particle-size fractions, coarse waste (WF), sand-sized (SF), silt-sized (SiF), clay-sized (CF) and dissolved organic matter-sized fraction (DOM). The SiF made a greater contribution to the formation of non-extractable residues in unamended soil, but when vermicomposts were added, new sorption sites in WF appeared, being higher for the more humified vermicompost V2. The dissolved organic carbon (DOC) increased with the addition of vermicompost, but the concentration of the desorbed 14C-radiochemical did not increase. Non-significant increment was observed with time for the non-extractable fraction with amendments. Diuron was transformed in all samples, although less than 0.5% was mineralized. The main effect caused by vermicomposts was a reduction in the availability of diuron in soil.     

Biodegradability of Chemically Modified Starch (RS4)/PVA Blend Films: Part 2

Biodegradable films were successfully prepared by using cornstarch (CS), chemically modified starch (RS4), polyvinyl alcohol (PVA), glycerol (GL), and citric acid (CA). The physical properties and biodegradability of the films using CS, RS4, and additives were investigated. The results of the investigation revealed that the RS4-added film was better than the CS-added film in tensile strength (TS), elongation at break (%E), swelling behavior (SB) and solubility (S). Especially, the RS4/PVA blend film with CA as an additive showed physical properties superior to other films. Furthermore, when the film was dried at low temperature, the properties of the films clearly improved because the hydrogen bonding was activated at low temperature. The biodegradation of films was carried out using the enzymatic, microbiological and soil burial test. The enzyme used in this study was amyloglucosidase (AMG), α-amylase (α-AM) and β-amylase (β-AM). At the enzymatic degradation test, the GL-added films had an approximately 60% degradation, while the CA-added films were degraded about 25%. The low degradation value on CA-added film is attributed to low pH of film added CA that deactivated the enzymatic reaction. The microbiological degradation teat was performed by using Bacillus subtilis and Aspergillus niger.     

Natural Weathering of Polypropylene and Waste Tire Dust (PP/WTD) Blends

Three series of polypropylene and waste tire dust (PP/WTD) blends using three different WTD sizes were prepared, compression-molded and cut into dumbbells. The specimens were exposed to natural weathering in the northern part of Malaysia for a period of 6 months. The results show that at the same blend composition, blends with fine WTD size exhibit higher mechanical properties than that of blends with coarse WTD after exposure to natural weathering. Regardless of WTD size, the retention of tensile strength and elongation at break, E_b increases with the increase in WTD content. From the exposed surface morphology, it is apparent that the blends with fine WTD and WTD-rich blends were able to withstand weathering better than blends with coarse WTD and PP-rich blends. The DSC thermograms suggest that the overall drop in melting temperature (T_m) of the exposed blends decreases as the WTD content increases.     

Environmental personalization and elementary school children's self-esteem

Prior research indicates that the physical classroom environment has the potential to affect children's behaviors, academic performance, and cognitive development. However, less is understood about the effect on the socio-emotional development of children. This study investigates the potential role of one aspect of the classroom's physical environment, personalization displays, on children's self-esteem. The study employed a classroom intervention in a quasi-experiment to examine the effects of increasing environmental personalization on children's self-esteem. Thirty-eight kindergarteners and first graders in six classrooms of two elementary schools in a rural community of a north-eastern state were assessed on pretests and post-tests of the Self-Esteem Index (SEI) scale and the Children's Inventory of Self-Esteem (CISE) scale. The findings were mixed but encouraging. On both measures of self-esteem, there was a significant positive effect of classroom personalization for first graders. However, for kindergarteners there was a significant positive effect for only one measure, the CISE. Although there are limitations with the study design, the findings suggest that young children's self-esteem may be influenced and enhanced by specific aspects of the classroom's physical environment.     

污染底泥释放控制技术的研究进展

从受污染底泥的危害入手 ,提倡在有效控制外源的同时 ,积极对受污染底泥的释放进行控制。根据控制方法原理的不同将污染底泥释放控制技术分为物理控制技术及生物控制技术 ,并综述了上述控制技术的研究及应用概况 ,并对其利弊作出评价 .最后 ,分析了受污染底泥释放控制技术的发展方向。     

重金属污染土壤修复技术现状与展望

目前重金属污染土壤修复主要采用物理化学技术和植物修复技术。根据其作用过程和机理,物理化学技术主要包括化学固化、土壤淋洗和动电修复;植物修复技术包括植物稳定、植物挥发和植物提取。本文就修复技术的原理、优缺点、实用性及研究现状与发展动态等方面进行了综述与分析。     

基于非洗井情况下地下水样品代表性探讨

将非洗井法采样筛管部位取样的可行性和洗井前后样品代表性作对比,当监测井中地下水流量为0.1 L/min~0.5 L/min时,用微扰动采样器在非洗井情况下采样。洗井前后常规无机离子浓度和5种物理指标的研究对比结果显示,在非洗井情况下用微扰动地下水采样器在筛管部位取样的样品与洗井之后的样品十分接近。6口监测井水中无机离子含量单方向方差分析结果显示,p值0.05(显著性),验证概率FF crit,表明在95%的置信度上可总结为无机化学参数在洗井前后无显著性差异。     

3-D dispersion model for simulation of accidental toxic gas releases in a metropolitan area

Computational fluid dynamic (CFD) simulations were performed to assess the potential chlorine leak scenario in the super-urban area of South Korea, where the human population density is very high and numerous buildings exist near operational water treatment facilities. Flame acceleration simulator (FLACS) was used to predict the consequence from accidental chlorine releases out of one of the water treatment facilities for the nearby area having a size of 5 km × 3 km approximately. The ability to precisely implement 3-D geometries is crucial for a successful 3-D simulation. Thus, a method was proposed to rapidly and accurately implement geometry by importing computer aided-design (CAD) files provided by a government agency, and processing them using Auto CAD and MicroStation software programs. An accidental release from an 18-ton tank was simulated with three different wind directions to determine the expected evacuation distances. Results from the study showed that the endpoint distances varied depending on the density and arrangement of the buildings. Moreover, we employed physical barriers with varying heights for mitigating the effects of toxic gas releases and simulated how effectively they decreased the concentration of released chlorine.