Fate of plasticised PVC products under landfill conditions: a laboratory-scale landfill simulation reactor study

The long-term behaviour of plasticised PVC products was investigated in laboratory-scale landfill simulation reactors. The examined products included a cable material and a flooring with different combinations of plasticisers. The objective of the study was to assess whether a degradation of the PVC polymer or a loss of plasticisers occurred under landfill conditions. A degradation of the polymer matrix was not observed. The contents of plasticisers in aged samples was determined and compared to the respective original products. The behaviour of the various plasticisers was found to differ significantly. Losses of DEHP and BBP from the flooring were too low for analytical quantification. No loss of DIDP from the cable was detectable, whereas DINA in the same product showed considerable losses of up to 70% compared to the original contents. These deficits were attributable to biodegradation rather than leaching. There was no equivalent release of plasticisers into the leachate.     

Emissions of DEHP‐free PVC flooring

Degrading 2‐ethylhexyl‐containing PVC floorings (eg DEHP‐PVC floorings) and adhesives emit 2‐ethylhexanol (2‐EH) in the indoor air. The danger of flooring degradation comes from exposing occupants to harmful phthalates plasticisers (eg DEHP), but not from 2‐EH as such. Since the EU banned the use of phthalates in sensitive applications, the market is shifting to use DEHP‐free and alternative types of plasticisers in PVC products. However, data on emissions from DEHP‐free PVC floorings are scarce. This study aimed at assessing the surface and bulk emissions of two DEHP‐free PVC floorings over three years. The floorings were glued on the screed layer of concrete casts at 75%, 85%, and 95% RH. The volatile organic compounds (VOCs) were actively sampled using FLEC (surface emissions) and micro‐chamber/thermal extractor (µ‐CTE, bulk emissions) onto Tenax TA adsorbents and analyzed with TD‐GC‐MS. 2‐EH, C9‐alcohols, and total volatile organic compound (TVOC) emissions are reported. Emissions at 75% and 85% RH were similar. As expected, the highest emissions occurred at 95% RH. 2‐EH emissions originated from the adhesive. Because the two DEHP‐free floorings tested emitted C9‐alcohols at all tested RH, it makes the detection of flooring degradation harder, particularly if the adhesive used does not emit 2‐EH.     

PVC／ABS／CPE共混体系的相容性与性能研究

聚氯乙烯（PVC）／丙烯晴－丁二烯－苯乙烯共聚物（ABS）共混体系为不相容体系。如入增容剂氯化聚乙烯（CPE）后,相容性明显提高,为部分相容;通过改变ABS用量可调节PVC／ABS／CPE共混体系的韧性;就不同ABS含量对PVC／ABS／CPE共混体系的相容性、拉伸强度、弯典强度、冲击强度、硬度、耐热性能以及耐水性能的影响进行了研究,结果表明,随着ABS含量的增加,PVC／ABS／CPE共混体系的拉伸强度、耐热性、吸水性略有增加,冲击强度有较大提高,而弯曲强度略有下降;当ABS含量超过30％（质量分数）后,共混体系的冲击强度基本上与ABS的相当;ABS含量低于70％（质量分数）的共混体系的表面硬度高于ABS的硬度,基本上与硬质PVC的接近。     

PVC／ABS共混物的性能和应用

PVC树脂和ABS树脂能相互进行改性,PVC/ABS共混物则集这两种树脂的特性于一体。阐述了PVC/ABS共混物的性能与组成的关系,介绍了它在化学建材方面的应用。     

Volatile organic components migrating from plastic pipes (HDPE,PEX and PVC) into drinking water

High-density polyethylene pipes (HDPE), crossbonded polyethylene pipes (PEX) and polyvinyl chloride (PVC) pipes for drinking water were tested with respect to migration of volatile organic components (VOC) to water. The odour of water in contact with plastic pipes was assessed according to the quantitative threshold odour number (TON) concept. A major migrating component from HDPE pipes was 2,4-di-tert-butyl-phenol (2,4-DTBP) which is a known degradation product from antioxidants such as Irgafos 168(R). In addition, a range of esters, aldehydes, ketones, aromatic hydrocarbons and terpenoids were identified as migration products from HDPE pipes. Water in contact with HDPE pipes was assessed with respect to TON, and values > or =4 were determined for five out of seven brands of HDPE pipes. The total amount of VOC released to water during three successive test periods were fairly constant for the HDPE pipes. Corresponding migration tests carried out for PEX pipes showed that VOC migrated in significant amounts into the test water, and TON >/=5 of the test water were observed in all tests. Several of the migrated VOC were not identified. Oxygenates predominated the identified VOC in the test water from PEX pipes. Migration tests of PVC pipes revealed few volatile migrants in the test samples and no significant odour of the test water.     

Estimation of the chloride diffusion from migration test using electrical current

Migration is the movement of ions in a solution under an electrical potential gradient. This paper presents a new method for determining the non-steady-state migration coefficient in mortar by measuring the electrical current from an accelerated chloride migration test (ACMT). Mortar specimens made with different water-to-cement ratios were tested. In this study, the electrochemical technique was applied to accelerate the ingress of chloride ions in the specimen. The non-steady-state migration coefficient in mortar was determined based on the measurements of the time lag (time needed for chloride ion to penetrate through the specimen). Both the chloride concentration in the anode cell and the electrical current were used to obtain the time lag. The non-steady-state migration coefficient obtained from the chloride concentration was compared with that obtained by the electrical current. From the results, a linear correlation between the non-steady-state migration coefficients obtained from chloride concentration and electrical current was obtained.     

Sensory and chemical evaluation of odorous emissions from building products with and without linseed oil

Natural materials of biological origin degrade over time and may emit odorous chemical compounds that can influence the perceived indoor air quality. The objective of this study was to investigate how the perceived air quality is influenced by emissions from building products with linseed oil compared with similar conventional synthetic products without linseed oil. Two types of linoleum, two types of wall paint and two types of floor oil were selected as examples of natural products containing linseed oil. The selected synthetic products were PVC floor covering, a water-based paint, and a synthetic floor oil. The emissions from the products were monitored over a one-year period in small ventilated test chambers. The odorous emissions were evaluated by sensory panel assessments of odour intensity and acceptability and by chemical analysis of the odour-active volatile organic compounds (VOCs) and carbonyl compounds. Odour-active VOCs in the emissions from one floor oil with linseed oil and two pure linseed oils were detected by gas chromatography combined with olfactometry (GC-O) and attempted identified with mass spectrometry (MS). The products with linseed oil influenced the perceived air quality more negatively than the similar synthetic products and the odour was persistent over time. It was found that the products with linseed oil did not qualify for the Danish Indoor Climate Label, because of the persistency of the odour. The results of the GC-O/MS investigations and VOC measurements indicated that an almost constant emission of odour-active VOCs with low odour thresholds resulted in the persistency of the odour. The VOCs probably originated from oxidation products from the linseed oil used as raw material. The study indicates that the acceptability of the emissions from the floor oil was influenced by the linseed oil used as raw material. It is therefore suggested that systematic use of less odorous linseed oils may improve the acceptability of the emission from products with linseed oils. The applied combination of sensory assessment of perceived air quality and GC-O/MS seems to be a useful approach in the effort to eliminate unwanted odours from building products.     

Regional labor markets in Finland: Adjustment to total versus region-specific shocks

This article analyses regional labor market adjustment in the Finnish provinces during 1976–2000. We investigate the inter-relations of employment, unemployment, labor force participation, and migration to see how a change in region-specific and total labor demand is adjusted. The analysis reveals that region-specific labor demand shocks adjust mainly via participation, whereas total shocks are adjusted by unemployment. The region-specific component of labor demand shock has shorter-lived effects on unemployment and participation, but its effect on employment is permanent. Conversely, total shocks leave no permanent effect. Migration is more important in the region-specific case where, after a few years, it acquires a large role in the adjustment process.     

Experimental Study of LNAPL Migration in the Vicinity of a Steep Groundwater Table

Migration of Light Non-Aqueous Phase Liquids (LNAPLs) in porous soils was studied experimentally, using one-dimensional and two-dimensional laboratory tests. The movement of crude oil under constant pressure was observed in vertical and horizontal transparent columns filled with sand. It was found that in both cases the average oil saturation does not change during the oil propagation. Its value depends on the initial water saturation in sand and the mobility of air in front of the oil front. The hydraulic conductivity to oil was found to be constant along the vertical column, while it decreased exponentially when oil was spreading along the horizontal column. Two-dimensional experiments were carried out in a sand tank with simultaneous water flow and the oil migration. Oil leaked into the sand from a thin feeder above the water table with constant oil level. The experiments were conducted with three types of LNAPL: crude oil, vegetable oil, and engine oil. Evolution of the oil mound was recorded through the transparent front wall of the sand tank, while the water table was monitored using a series of piezometers. Presence of the water table had a major effect on the oil mound shape and size. Downwards movement of the oil front slowed down around the top of the capillary fringe and completely stopped near the water table. The depth of penetration into the capillary fringe depended on the oil viscosity and the pressure at the oil source. Lateral spreading was more pronounced in the direction of the water movement.     

Migration and regional science: opportunities and challenges in a changing environment

Migration studies have a long history within regional science. This paper reviews the current status of migration research within regional science and asks whether migration continues to maintain the presence and import in regional science that appeared in earlier, similar analyses such as Anselin and Rey (Int Reg Sci Rev 23(4):323–344, 2000) and Plane and Bitter (Pap Reg Sci J RSAI 76:133–153, 1997). The paper looks at the relative strength of migration studies within regional science and the challenges (and concomitant) opportunities that are available. It begins by replicating a portion of a 1997 study by Plane and Bitter which evaluated the prevalence of migration research within the regional science literature. Based on findings that the proportion of both migration and population-themed papers have decreased, the paper then considers the challenges facing researchers, including data and training challenges, along with the need to ensure that migration research remains relevant, before offering concluding remarks.     

Performance of oil palm empty fruit bunch fibres coated with acrylonitrile butadiene styrene

Natural fibres are suitable for reinforcement of soils due to their availability, low cost and environment-friendly nature. Oil palm empty fruit bunches (OPEFB), solid waste produced during refinement of oil from oil palm fruit, provide fibres which have been used as reinforcement material for soil improvements. To protect the fibres from biodegrading in reinforced soil, OPEFB fibre is coated with non-biodegradable material. The effect of coating OPEFB fibres with acrylonitrile butadiene styrene (ABS) was evaluated. Morphological characterization, mechanical and physical properties of the coated fibres exhibited improved fibre performance. The ABS treatment protected fibres from water absorption and decreased the biodegradation potential of the fibres in contact with soil. The tensile strength and elasticity moduli of the OPEFB fibres were also improved with the coating. Coating fibres increases interface friction between fibre and soil particles due to increased surface area. The results were shown that the shear strength parameters of the fibre-reinforced soils can be improved significantly.     

从混凝土减水剂的微观特征看减水剂的合成

从混凝土减水剂的活性官能团、分子结构和分子量三个方面分析了减水剂的微观特征及在合成中存在的问题,认为：开展聚磺酸-聚羧酸系高性能减水剂的研究是应该深入而有价值的;减水剂的梳状结构使减水剂具有非常好的分散性能,这是减水剂合成的重要方向;关于减水剂分子量的研究还存在一些问题,还需要深入进行探讨.     

The effect of ignition source exposure and specimen configuration on the fire growth characteristics of a combustible interior finish material

The potential fire hazard presented by plastic based combustible interior finish materials is discussed. Compartment fire experimental methods and apparatus based on Uniform Building Code Standard No. 42-2 were used to study the effect of ignition source exposure and specimen configuration on the actual fire growth characteristics of polyvinyl chloride (PVC) foam wall covering. The results obtained are qualitative in nature, clearly demonstrating two important characteristics of the fire behavior of PVC foam: (i) the PVC foam has a ‘critical’ ignition source strenght of 64–75 kW; (ii) preheating the PVC foam greatly increases its peak net rate of heat release.     

Feasibility of Treatment of Refinery Wastewater by a Pilot Scale MF/UF and UF/RO System for Reuse at Boilers and Cooling Towers

A pilot-scale hybrid membrane system, consisting of a ceramic microfilter (MF), two differentpolyvinyl chloride (PVC) and polyacrylonitrile (PAN) ultrafilters (UF), and a polyamide reverse osmosis (RO) filter, has been utilized to decrease harmful and damaging components in wastewater produced from Tehran Refinery with aim to be reused at boilers and cooling towers. Taguchi method was employed to find optimum operating conditions including transmembrane pressure, cross flow velocity (CFV), temperature, and backwash time. Further, analysis of variance (ANOVA) was performed to determine the significance of controlling factors on total organic carbon rejection and normalized permeate flux. MF (ceramic)/UF (PVC) system reduced, %: oil 99.7; chemical oxygen demand (COD) 82; biochemical oxygen demand (BOD) 79.3; conductivity 60.5; total dissolved solids (TDS) 52.6; turbidity 99.7 and total hardness 73.2. MF(ceramic)/UF (PAN) system reduced: oil, COD, BOD, conductivity, TDS, turbidity, and total hardness by 99.8; 84.2; 80.8; 62.72; 55; 99.9 and 78.4%, respectively. UF (PAN)/RO system decreased, %: oil 99.5; COD 99; BOD 99; conductivity 98; TDS 98; turbidity 98.7 and total hardness 99.94. Obtained treated wastewater by this system can be reused as feed water of boilers.     

Phytoplankton,pelagic community and nutrients in a deep oligotrophic alpine lake: ratios as sensitive indicators of the use of P-resources (DRP:DOP:PP and TN:TP:SRSi)

The different use of P-resources between two sites in the deep oligotrophic Traunsee was studied by seasonal and vertical patterns of phytoplankton and nutrients from 12/1997 to 10/1998. The P-resources were evaluated from the proportion between the P-fractions, the dissolved reactive P (DRP), dissolved non-reactive P (DOP) and particulate organic P (PP) and from the stoichiometry between nutrients, the total N (TN), the total P (TP) and soluble reactive Si (SRSi). Significant differences between an inshore site impacted by industrial tailings (Ebensee Bay, EB) and an open water reference site (Viechtau, VI) were evident from vertical profiles of both the P-accumulation (%PP of TP) evaluated by DRP:DOP:PP and the distribution of phytoplankton assessed by Si-exhaustion (TN:TP:SRSi), but not from the seasonal patterns of phytoplankton composition, S:V ratios of the algal community or surface layer nutrient dynamics. Low TP and the stable stratification from May to September triggered the relative accumulation of epilimnetic P at VI as it was evident from both the higher portion of particulate P within TP (%PP of TP) and from the shift towards P-enrichment in nutrient stoichiometry of TN:TP:SRSi. The predominance of around 55-52% algal carbon over bacteria at the surface layer to 20m coincided spatially with the lowest Si content relative to N and P. The disturbances at the impacted site was summarised by: up to 11% less P accumulation by organisms at the surface, no stoichiometric shift towards TP in the epilimnion when compared with deeper layers and a reduction of the trophogenic zone to the top 10m. Reasons for this disturbance are seen in the unstable stratification, turbidity, higher TP and the metazoan dominated food chain. Both triple ratios, DRP:DOP:PP and TN:TP:SRSi, were sensitive indicators of the use of P-resources by plankton communities, while inorganic dissolved fractions (DIN:DRP:SRSi, DIN = dissolved inorganic N) provided only insufficient information on nutrient resources in Traunsee.     

Effect of copper slag and cement by-pass dust addition on mechanical properties of concrete

This research was undertaken to study the effect of copper slag (CS) and cement by-pass dust (CBPD) addition on concrete properties. In addition to the control mixture, two different trial mixtures were prepared using different proportions of CS and CBPD. CBPD was primarily used as an activator. One mixture consisted of 5% copper slag substitution for portland cement. The other mixture consisted of 13.5% CS, 1.5% CBPD and 85% portland cement. Three water-to-binder (w/b) ratios were studied: 0.5, 0.6 and 0.7. Concrete cubes, cylinders and prisms were prepared and tested for strength after 7 and 28 days of curing. The modulus of elasticity of these mixtures was also evaluated. Results showed that 5% copper slag substitution for portland cement gave a similar strength performance as the control mixture, especially at low w/b ratios (0.5 and 0.6). Higher copper slag (13.5%) replacement yielded lower strength values. Results also demonstrated that the use of CS and CBPD as partial replacements of portland cement has no significant effect on the modulus of elasticity of concrete, especially at small quantities substitution.     

A comprehensive study on reduction of NOx emission applying EGR technique in a diesel engine using biodiesel (POME) as fuel with ether-based additives

The energy consumption is increasing rapidly due to population growth, improved living standards and industrialisation. A significant amount of fossil fuels is consumed by the transportation sector, which causes the fast depletion of fossil fuels and environmental pollution. These problems can be overcome by using Biodiesel. This research work aims to reduce the NO_x emission in diesel engines. The literature survey reveals that the use of a fuel additive reduces the emissions by oxygenating the fuel. Among oxygenates, ether proves to behave better than alcohols. Hence, for this present work, two different types of ethers were selected which were not used in earlier occasions. DGME (Diethylene Glycol Monomethyl Ether) and DGMB (Diethylene Glycol Monobutyl Ether) are the two additives selected from the ether group and used as additives with palm oil methyl ester (POME) biodiesel in various proportions and tested in a direct injection compression ignition engine which reduced the emissions. To start with, the engine was run with diesel and subsequently with biodiesel and with the additives. The performance tests were carried out in a single-cylinder, four-stroke, water-cooled engine with and without exhaust gas recirculation (EGR). This engine is coupled with eddy current dynamometer. The use of biodiesel in conventional diesel engines results in substantial reduction in emission of carbon monoxide, particulates and unburned hydrocarbons, but increases NO_x emission. This review focuses on reduction of NO_x emission. Combustion and performance analysis of the engine have also been evaluated.     

Export of dissolved organic matter in relation to land use along a European climatic gradient

The terrestrial export of dissolved organic matter (DOM) is associated with climate, vegetation and land use, and thus is under the influence of climatic variability and human interference with terrestrial ecosystems, their soils and hydrological cycles. We present a data-set including catchments from four areas covering the major climate and land use gradients within Europe: a forested boreal zone (Finland), a temperate agricultural area (Denmark), a wet and temperate mountain region in Wales, and a warm Mediterranean catchment draining into the Gulf of Lyon. In all study areas, DOC (dissolved organic carbon) was a major fraction of DOM, with much lower proportions of DON (dissolved organic nitrogen) and DOP (dissolved organic phosphorus). A south-north gradient with highest DOC concentrations and export in the northernmost catchments was recorded: DOC concentrations and loads were highest in Finland and lowest in France. These relationships indicate that DOC concentrations/export are controlled by several factors including wetland and forest cover, precipitation and hydrological processes. DON concentrations and loads were highest in the Danish catchments and lowest in the French catchments. In Wales and Finland, DON concentrations increased with the increasing proportion of agricultural land in the catchment, whereas in Denmark and France no such relationship was found. DOP concentrations and loads were low compared to DOC and DON. The highest DOP concentrations and loads were recorded in catchments with a high extent of agricultural land, large urban areas or a high population density, reflecting the influence of human impact on DOP loads.     

Migration history,migration behavior and selectivity

A series of proportional hazards models are used to study the relationship between migration history and migration behavior for a sample of young adults from the National Longitudinal Survey of Youth. The results support the argument that migration is a selective process. College educated young adults have a greater hazard rate of making an initial migration but a lower hazard rate of re-migration, suggesting they have less need of corrective geographic behavior. Individuals who have moved two or more times are less responsive to national unemployment conditions than first time migrants. Migration is related to the timing of unemployment within a sojourn. The findings suggest that migrant stock is an important determinant of how labor markets function.     

Studies on vinyl chloride migrating into drinking water from polyvinyl chloride pipe and reaction between vinyl chloride and chlorine

To determine the conditions for the migration of vinyl chloride monomer (VCM) into water from polyvinyl chloride (PVC) pipes and to examine the reaction between VCM and the chlorine present in drinking water, we studied the migration of VCM into water. It was found that migration of VCM into water from PVC pipes (containing 29.5 ppm VCM) could only be detected by using an apparatus that prevented volatilization of VCM and increasing the surface area of the pipe wall in contact with the water. The amount of VCM which could undergo action of the chlorine in the water decreased markedly with the age of the pipes and when the pH was lowered. VCM occurred in the water was converted to chloroacetaldehyde, chloroacetic acid, etc., by its reaction with chlorine, while the amounts of these reactants varied with pH of the solution was changed.