Uptake of Radionuclides onto Suspended Particulate Matter in Coastal Water

Distribution coefficients K _ds of several radionuclides on suspended particulate matter (SPM) have been determined with laboratory batch experiments using samples collected in the Kinki district, Japan. Most SPM in coastal water was retained on the initial filter of four sequential filtering stages (20, 5, 1 and 0.45 μm pore size), maximum K _d also being found for the SPM retained in this first stage. When the filtrations were not performed in series, however, but were conducted from the same tracer solution in parallel, the K _d values were identical for the smaller filter sizes (5, 1 and 0.45 μm) and were greater, by ca. 150% than those derived from the 20 μm filter. The degree of association of the radionuclides with SPM was ⁸⁵Sr<¹³⁷Cs<⁶⁵Zn<⁵⁴Mn<⁶⁰Co. The particulate radioactivity fraction of the SPM in coastal water was estimated at most 0.1 for radionuclides with K _d of ca. 5 X 10⁴ ml/g, i.e. which are highly associated with the SPM (2 mg/l). The scavenging effect by SPM seemed to be, however, considerable, the settling velocity being estimated at ca. 25 cm/day for particles of the Stoke's diameter of 30 μm.     

Particulate matter chemical component concentrations and sources in settings of household solid fuel use

Particulate matter (PM) air pollution derives from combustion and non‐combustion sources and consists of various chemical species that may differentially impact human health and climate. Previous reviews of PM chemical component concentrations and sources focus on high‐income urban settings, which likely differ from the low‐ and middle‐income settings where solid fuel (ie, coal, biomass) is commonly burned for cooking and heating. We aimed to summarize the concentrations of PM chemical components and their contributing sources in settings where solid fuel is burned. We searched the literature for studies that reported PM component concentrations from homes, personal exposures, and direct stove emissions under uncontrolled, real‐world conditions. We calculated weighted mean daily concentrations for select PM components and compared sources of PM determined by source apportionment. Our search criteria yielded 48 studies conducted in 12 countries. Weighted mean daily cooking area concentrations of elemental carbon, organic carbon, and benzo(a)pyrene were 18.8 μg m^?3, 74.0 μg m^?3, and 155 ng m^?3, respectively. Solid fuel combustion explained 29%‐48% of principal component/factor analysis variance and 41%‐87% of PM mass determined by positive matrix factorization. Multiple indoor and outdoor sources impacted PM concentrations and composition in these settings, including solid fuel burning, mobile emissions, dust, and solid waste burning.     

Exploratory analysis of excitation-emission matrix fluorescence spectra with self-organizing maps—A tutorial

Large datasets are common in chemical and environmental engineering applications and tools for their analysis are in great demand. Here, the outputs of a series of fluorescence spectroscopy analyses are utilised to demonstrate the application of the self-organising map (SOM) technique for data analysis. Fluorescence spectroscopy is a well-established technique of organic matter fingerprinting in water. The technique can provide detailed information on the physico-chemical properties of water. However, analysis of fluorescence spectra requires the application of robust statistical and computational data pre-processing and analysis tools.This paper presents a tutorial for training engineering postgraduate researchers in the use of SOM techniques using MATLAB^®. Via a tutorial, the application of SOM to fluorescence spectra and, in particular, the characterisation of organic matter removal in water treatment, is presented. The tutorial presents a step-by-step example of the application of SOM to fluorescence data analysis and includes the source code for MATLAB^®, together with presentation and discussion of the results. With this tutorial we hope to popularise this robust pattern recognition technique for fluorescence data analysis and large data sets in general, and also to provide educational practitioners with a novel tool with which to train engineering students in SOM.     

A comparison for Turkish provinces’ performance of urban air pollution

The objective of this paper is to assess the environmental performance of Turkish provinces by using a non-parametric method, Data Envelopment Analysis. The results of ranking are based on the provinces’ ability to produce the largest equi-proportional increase in the desirable output-gross domestic product and decrease in the undesirable output namely, air pollutants. The results indicate that 7.41% of the sample provinces are relatively efficient. The results also show that, regions with the highest level gross domestic product per capita have the highest efficiency scores. New industrial districts have lower efficiencies in spite of relatively higher income per capita. In the second stage of the study the possible relationship between environmental efficiency scores and input, output variables are investigated by a regression analysis. According to the results, there is a positive relationship between gross domestic product and efficiency scores.     

Collective cell migration: leadership,invasion and segregation

A number of biological processes, such as embryo development, cancer metastasis or wound healing, rely on cells moving in concert. The mechanisms leading to the emergence of coordinated motion remain however largely unexplored. Although biomolecular signalling is known to be involved in most occurrences of collective migration, the role of physical and mechanical interactions has only been recently investigated. In this study, a versatile framework for cell motility is implemented in silico in order to study the minimal requirements for the coordination of a group of epithelial cells. We find that cell motility and cell–cell mechanical interactions are sufficient to generate a broad array of behaviours commonly observed in vitro and in vivo. Cell streaming, sheet migration and susceptibility to leader cells are examples of behaviours spontaneously emerging from these simple assumptions, which might explain why collective effects are so ubiquitous in nature. The size of the population and its confinement appear, in particular, to play an important role in the coordination process. In all cases, the complex response of the population can be predicted from the knowledge of the correlation length of the velocity field measured in the bulk of the epithelial layer. This analysis provides also new insights into cancer metastasis and cell sorting, suggesting, in particular, that collective invasion might result from an emerging coordination in a system where single cells are mechanically unable to invade.     

含水固形物干燥脱水蒸汽再利用专利技术工艺及设备

在无机盐产品生产过程中,中间产品和副产品通常需要进行干燥,文章对含水固形物干燥脱水蒸汽再利用工艺及设备进行了论述。并就干燥脱水蒸汽再利用专利工艺及设备对节省能源消耗进行了分析。     

基于云物元的混凝土坝裂缝危害性评价模型

针对数据的随机性和等级标准划分模糊的特点,建立了水工混凝土坝裂缝危害性评估的云物元模型,首先依据已有的指标体系和等级评价标准确定相应的云模型参数,采用AHP-熵权法计算评估指标的综合权重;然后以某重力坝为例,计算样本指标属于各评价等级的隶属度,依据最大隶属度原则确定裂缝对坝体结构影响的危害级别。最后将云物元模型与可变模糊模型进行比较,两种模型的评价等级相同,由此证明云物元模型合理、可行,为裂缝的危害性评价提供了一种新方法。     

Characterization of EfOM Fraction Responsible for Short-Term Fouling in Ultrafiltration

Based on our earlier diagnosis that hydrophobic and hydrophilic (HPO/HPI) acids are the primary cause of short-term fouling in the ultrafiltration of secondary effluent, the HPO/HPI acids were extracted and subsequently characterized in comparison with commercial organic materials. HPO/HPI acids isolated from secondary effluent contained significantly fewer complex mixtures than humic substances that have been implicated as the dominant foulants in the filtration of surface water using porous membranes. The physicochemical and spectroscopic characterization demonstrated that the aromaticity and apparent molecular weight of HPO/HPI acids were lower than that observed for other humic materials, while the oxygenated functional groups were relatively higher.     

Wastewater desalination system utilizing a low‐temperature heat pump

A wastewater desalination system based on a low‐temperature air source heat pump was developed and studied in this paper. The system consists of 2 main parts: the wastewater flow process and the heat pump cycle. A series of experiments were conducted on the system under different conditions, and the effect of the evaporation temperature was investigated. This system can reach equilibrium at any evaporation temperature using the combination of the compressor and vacuum pump. To treat wastewater with low boiling point organic matter, the system was operated at a low evaporation temperature of 48°C. The organic matter remained in the concentrated wastewater, and the organic removal was approximately 97%. Three kilograms of treated water was produced in 1 hour with an energy consumption of 250 W. The performance ratio (PR) obtained from the experiments ranged from 4.6 to 7.3. The cost for treating 1 kg of water was 0.038 yuan CNY assuming 0.5 yuan CNY per kWh at the compressor frequency of 50 Hz.     

Inhalation risk of indoor aerosol spray products commercially available in Bangladesh

Today, urbanised people spend most of their time in indoor environments, and the risk of exposure to toxic materials in an indoor environment is of great concern. This paper considers sources for the inhalation risk of aerosol sprays by measuring the particle size distributions of some of the most popular products that are commercially available in Bangladesh, and examines the degree of toxicity and the health risk via the respirability of the products. Results show that thoracic and respirable fractions of the suspended particulate matter are present in the tested samples and hence the spray products may pose a significant health risk.