Polystyrene/wood composites and hydrophobic wood coatings from water-based hydrophilic-hydrophobic block copolymers

The combination of synthetic thermoplastic polymers and wood is normally problematic because wood surfaces are hydrophilic while typical thermoplastic polymers are hydrophobic. A possible solution is to use block copolymer coupling agents. In this work we show the use of a potentially useful synthetic method of producing hydrophilic-hydrophobic block copolymers as hydrophobic coatings and coupling agents in polystyrene/wood flour composites. In particular, wood veneers are coated with water-based emulsions of hydrophilic-hydrophobic block copolymers from styrene and methacrylic acid. Dried coated surfaces are shown to become hydrophobic through dynamic contact angle measurements. When wood flour is coated with the hydrophilic-hydrophobic block copolymer based on styrene and acrylic acid, significant improvement in the ultimate tensile properties of composites formed from coated wood flour/polystyrene mixtures is realized. Since no volatile organic compounds (VOCs) are used in coating wood surfaces and subsequent composite production, improvement in mechanical properties of thermoplastic/wood flour composites are shown to occur in environmentally responsible formulations.     

高原气候环境对涂层材料性能的影响研究

太阳辐射是引起有机涂层老化的最主要原因。由于高原拉萨地区的太阳辐射年总量比内地同纬度高出约一倍,分别将3种同基材同镀层但不同底漆和面漆的6类常用防护涂层在高原气候条件下自然暴露试验一年。经过对比,能较快速优选出性能相对稳定的涂层。     

MODELING A CONCRETE BLOCK IRRIGATION DIVERSION SYSTEM1

ABSTRACT: Concrete block irrigation diversion systems have been proposed as alternatives to permanent dams of concrete or rock or temporary gravel berms. Permanent dams can cause stream channel instability, bank erosion, sediment pollution, ice flow blockage, and safety problems for recreational floating craft. Temporary berms can require substantial streambed disturbance and can promote sediment pollution, stream bank instability, and bank erosion. A design procedure was developed based on a model of the hydraulic performance of concrete block diversion systems. The procedure was used to model a site on the Gallatin River in Montana. The method relies on HEC-RAS (Hydrologic Engineering Center -River Analysis System) software combined with analytical techniques in an iterative scheme. The hydraulic performance of different diversion configurations (the existing heavy-rock diversion system, concrete blocks oriented parallel to flow, and concrete blocks oriented diagonally) was assessed using the model under a range of flow rates. The minimum diversion dimensions (length, number, and size of blocks) that maintained block stability while diverting the requisite flow were determined for each model run. At the Gallatin River site, the block system oriented parallel to flow required less diversion material than the diagonal orientation. The recommended diversion length was 51.8 m (170 ft). Trapezoidal blocks with a top width of 20.3 cm (8 in), a height of 45.7 cm (18 in), and side slopes of 2 vertical to 1 horizontal were specified. This configuration minimizes the total block mass, diverts the required flow, and has a factor of safety of 2.0 against block displacement.     

有机涂层户外失效分析及对策

我国气候类型复杂,有机涂层在一些典型气候条件下经过一段时间的户外暴露后都会出现粉化、颜色变化、剥落、沾污等明显变化.综合起来分析,当地太阳辐射强度、辐射量、温湿度等是有机涂层失效的主要因素;同时空气中的污染物、沙尘等也加速了有机涂层失效.因此研制新型户外涂料时要确保有机涂层既能起防护作用,又能起装饰作用,以增强有机涂层...     

南通市典型臭氧污染过程VOCs特征及来源分析

利用在线挥发性有机物自动监测仪TH300B对2020年8月12—17日南通市典型臭氧污染过程中VOCs排放进行监测。结果表明,南通市此次臭氧污染过程主要受VOCs排放影响,污染中VOCs体积浓度均值为23.44 ppb,较污染前下降了12.0%,其中芳香烃体积浓度占比下降幅度最大,较污染前下降23.4%,OVOCs体积浓度绝对值下降最大,较污染前下降1.42 ppb。污染中,VOCs总OFP贡献为162.0μg/m3,较污染前下降22.2%,OPF与臭氧的日变化呈明显的相反关系,关键活性物种为甲苯、乙烯和异戊烷等。PMF模型解析结果显示,机动车尾气、工业排放、油气挥发、涂料和溶剂使用、天然气源对VOCs的贡献占比分别为38.6%,35.4%,9.5%,8.8%和7.8%。     

Characterization of total volatile organic compound emissions from paints

Recently, Homeswest in Western Australia and Murdoch University developed a project to construct low allergen houses (LAH) in a newly developed suburb. All potential volatile organic compound (VOC) emission materials used in LAH are required to be measured before the construction of LAH, to ensure they are low VOCs emission materials. To protect people sensitive to exposure to VOCs it is important to evaluate and select low VOCs emitting paints. In this paper, therefore, twelve different paints provided by local manufacturers were selected for analysis to characterize total volatile organic compounds (TVOC) emissions. Emissions of TVOCs from six organic solvent-soluble paints and six water-soluble paints were evaluated using a small test chamber under controlled temperature, relative humidity and air exchange rates. The major volatile organic compounds in these paints were also identified. The time dependence of TVOC emissions from paint products in the chamber was evaluated. TVOC emissions from organic solvent-soluble and water-soluble paints were compared. The influence of air exchange rate on the TVOC concentrations emitted from organic solvent-soluble and water-soluble paints was also investigated. A double-exponential equation was used to evaluate emission characteristics of TVOC from paint products. With this double-exponential model, the physical processes of TVOC emissions can be explained. A variety of emission parameters can be calculated and used to estimate real indoor TVOCs concentrations.     

DEVELOPING CONFIDENCE IN CONCRETE REVETMENT PRODUCTS FOR BANK STABILIZATION1

ABSTRACT: There is a need to provide flood protection while maintaining stable bed and bank conditions in the riverine system, to stabilize earth embankment dams and spiliways, and to stabilize highway or railway embankments and levee systems. One approach to providing erosion protection and stabilization of channel banks, embankments and spill conveyances is with articulated concrete block systems. Numerous articulated concrete block systems are available for bank stabilization. However, prior to field installations few means are available to evaluate how well these block systems perform. To assist the designer in predicting site specific suitability, a series of hydraulic testing protocols have been developed to analyze block system performance. Two articulated block system testing protocols are presented to indicate how block hydraulic characteristics may be determined and provide performance assurance to both the designer and the owner.     

活性炭纤维复合材料的脱硫性能

本实验以粘胶基活性炭纤维和酚醛树脂复合,制备出了一种可用于烟气脱硫的活性炭纤维复合材料（ACFM）,考察了制备工艺条件对脱硫性能和比表面积的影响,测试其在填充床的压降。结果表明：粘结剂用量、炭化及活化条件对样品的脱硫性能和比表面积有较大的影响;与其他活性炭材料相比ACFM压降相对较低,只有活性炭纤维的1／20。     

Hydro-abrasive erosion in hydro turbines: a review

The flow of sediment particles in rivers is a big challenge to develop hydropower plants across the sediment-laden rivers. Hard particles such as quartz and feldspar are available in high amount in the Asian mountain range. The abrasive action of these particles causes the hydro turbines to suffer from erosion in particular at high- and medium-head hydroelectric power plants. This has become a serious economic issue due to maintenance costs and production losses. The treatment without prevention is simply unsustainable. Facilities for sediment exclusion, typically sand traps as well as turbine design, and materials have been improved considerably. In the present paper, studies have been discussed extensively undertaken by several investigators in this field. Based on literature survey several aspects related to reducing the sediment load on turbines, useful ways to improve the turbine surface performance and various erosion models to characterize the effect of erosion on the performance of turbines have been discussed. To calibrate and validate the developed erosion models, more measurements from both physical model tests in laboratories and continuous monitoring of sediment parameters and their impact on the operational hydro turbines are required. As well as the state-of-art in the modeling and simulation using computational fluid dynamics (CFD) has made it possible to optimize the hydraulic design of hydro turbines in order to minimize the erosion level without much sacrifice in the efficiency. To mitigate the hydro-abrasive erosion effects on the performance of turbines, significant improvements have been achieved so far and development is ongoing.     

Development of blending chart for different degrees of blending of RAP binder and virgin binder

Recent studies have consistently shown that RAP mixed with virgin binder and aggregates results in partial blending; that is, a phase between 100% blending and the “black rock” effect occurs. The impact of partial blending on new virgin binder content is apparent and may cause under-asphalting of mixture, resulting in poor pavement performance. Influence of partial blending on critical grade of RAP mixes and allowable percentages of RAP have not been evaluated. The purpose of this paper is to develop the blending chart for different degrees of blending to study the impacts of partial blending on the critical grade of blended binder. To achieve the objective, blending charts for 100%, 70% and 50% degree of blending have been developed for PG 70-28 and PG 58-28 binder by mixing virgin and RAP binders in differing proportions. The higher critical grade of blended binder does not change for different degrees of blending (70% and 50%) for low percentages of RAP binder (25% and 35%) with PG 70-28 binder. However, for high percentages of RAP binder (50%) and low degree of blending (50%), higher critical grade of blended binder can cause grade change.     

我国标准气体应用于涉VOCs重点行业监测管理中的不足及建议

随着我国对VOCs监测控制的持续推进,VOCs标准气体的配套应用及其管理思路也面临着新要求和挑战。本文通过梳理我国VOCs类标准气体对涉VOCs企业污染物监测和管理支撑的现状,指出了VOCs监测管理中对标准气体的应用要求尚待细化、已有VOCs标准气体应用不够充分、VOCs标准气体对排放标准实施的精准支撑作用不足等问题。在探究现状与问题的基础上,提出进一步细化VOCs排放监测对标准气体应用要求、加强企业自行监测中VOCs标准气体的应用指导、加强短缺标准气体的研制与应用的建议。     

Occurrence of Volatile Organic Compounds in Aquifers of the United States1

Abstract: Samples of ambient ground water were collected during 1985‐2002 from 3,498 wells in 98 aquifer studies throughout the United States. None of the sampled wells were selected because of prior knowledge of nearby contamination. Most of these samples were analyzed for 55 volatile organic compounds (VOCs) to characterize their national occurrence. Volatile organic compounds were found in samples collected from 90 of the 98 aquifer studies. Occurrence frequencies of one or more VOCs for the 98 aquifer studies ranged from 0 to about 77% at an assessment level of 0.2 microgram per liter (μg/l). The aquifer studies with the largest occurrence frequencies were in southern Florida, southern New York, southern California, New Jersey, and Nevada. Trihalomethanes and solvents were the most frequently occurring VOC groups. Of the 55 VOCs included in this assessment, 42 occurred in at least one sample at an assessment level of 0.2 μg/l. Chloroform, perchloroethene, and methyl tert‐butyl ether were the most frequently occurring VOCs. Many factors, such as the hydrogeology of the aquifer, use of VOCs, land use, and the transport and fate properties of VOCs, affect the occurrence of VOCs in ground water.     

Nanoparticle aggregation: challenges to understanding transport and reactivity in the environment

Unique forms of manufactured nanomaterials, nanoparticles, and their suspensions are rapidly being created by manipulating properties such as shape, size, structure, and chemical composition and through incorporation of surface coatings. Although these properties make nanomaterial development interesting for new applications, they also challenge the ability of colloid science to understand nanoparticle aggregation in the environment and the subsequent effects on nanomaterial transport and reactivity. This review briefly covers aggregation theory focusing on Derjaguin-Landau-Verwey-Overbeak (DLVO)-based models most commonly used to describe the thermodynamic interactions between two particles in a suspension. A discussion of the challenges to DLVO posed by the properties of nanomaterials follows, along with examples from the literature. Examples from the literature highlighting the importance ofaggregation effects on transport and reactivity and risk of nanoparticles in the environment are discussed.     

油漆涂层老化黄变分析

汽车涂装后形成的涂层,既要具备较好的外观装饰效果,又必须具有优良的防护性能,而在实际使用过程中,常因涂层老化而发生的黄变,严重影响了其原有的性能要求。文章分析了涂层老化黄变的原因,对比分析了几种面漆的耐老化性能,并提出提高涂层耐黄变性能的措施。     

Magnetic particle technology in environmental remediation and wildlife rehabilitation

The use of magnetic particles in environmental remediation and wildlife rehabilitation is currently under investigation at Victoria University, in collaboration with the Phillip Island Research Centre, Victoria, Australia. Iron powder has been shown to be very effective for the magnetic cleansing of feathers and plumage and is almost ideal for this purpose, being non-toxic, a non-irritant and recyclable. Detailed investigations have demonstrated that by varying particle size, particle structure and surface texture, the efficacy of oil removal from feathers and plumage can be successfully manipulated. In this regard, it is possible to identify a grade of iron powder whereby, within experimental error, effectively 100% removal of a variety of fresh contaminants from different matrices, including feathers, can be achieved. Our investigations have been extended to the application of such particles to the successful removal of tarry and weathered/tarry contamination. The results of these investigations have indicated that, for such contaminants, removals ranging from 97–99% may be achieved. Magnetic particle technology may also be adapted for the screening of pre-conditioning agents that can further assist in the removal of tarry and weathered/tarry contamination from feathers. These investigations suggest that magnetic particles could have an important role to play in environmental remediation and wildlife rehabilitation as a clean and effective technology.     

Study on recycled asphalt concrete for use in surface course in airport pavement

This research investigated the possibility of using recycled asphalt concrete as surface course in airport pavement. The basic properties of recycled asphalt binder after short- and long-term aging were firstly tested and compared with those of the virgin asphalt. Then, a series of laboratory tests were performed to evaluate the performance of recycled asphalt concrete (containing 40% and 70% RAP), in which the HMA mixture without RAP was used as a control. Furthermore, an experimental pavement consisting of three sections (corresponding to 0%, 40% and 70% RAP content) was constructed to verify the laboratory test results. These results indicated that the recycled asphalt could achieve the similar properties against long-term aging as virgin asphalt. Recycled asphalt concrete containing 40% RAP could be used as surface course in airport pavement as it exhibited similar performance as control mixture both from the laboratory and experimental pavement test results. On the contrary, recycled asphalt concrete containing 70% RAP was not recommended as its fatigue property was much poorer compared with that of virgin asphalt mixture.     

Different formats of imprinted polymers for determining organotin compounds in environmental samples

Organotin compounds and their degradation products enter the environment mainly as a result of their use as biocides and antifouling paints. Analysis of these compounds in environmental samples has to be very sensitive and selective so that their concentrations corresponding to the low environmental target values can also be detected. Generally, analysis of a complex matrix leads to high interferences during the different process steps; clean-up procedures are recommended to overcome this problem. For the past many years, solid phase extraction by employing imprinted materials has been extensively used for many organic substances that are used for pre-concentration and clean-up purposes with excellent results. Here, we present three different imprinted polymers prepared via bulk, precipitation, and emulsion polymerization methods that use similar compositions. The synthesized polymer particles were characterized morphologically by employing scanning electron microscopy and Brunauer-Emmett-Teller analysis. Binding properties were calculated using the Langmuir-Freundlich isotherm. Depending on the properties of the materials, different analytical applications for complex matrices are proposed. These applications are mainly used on tributyltin and its degradation products for environmental analysis.     

挥发性有机废气净化技术研究进展

本文对生物净化技术、等离子体净化技术、吸附和催化氧化技术在控制废气中挥发性有机物的研究进展及应用进行了综述。气体生物净化技术在VOCs混合物和改进设备工艺方面开展的研究工作较多,等离子体净化技术与催化技术的组合越来越受到关注。吸附和催化氧化方面则着重在吸附剂（活性炭和沸石）吸附性能的进一步研究和新型催化剂的研制。     

TURBULENCE MEASUREMENT OF A FLOW WITH SUSPENDED SOLID PARTICLES1

ABSTRACT: Success in measuring turbulence in water has been achieved by replacing the hot-wire probe by the hot-film probe. Accordingly, these results have greatly increased knowledge and understanding of hydromechanics. However, there are few published measurements of turbulent properties of flow with suspended solid particles. With this in mind, the authors conducted measurements of turbulent properties of flow with suspended solid particles by using a quartz-coated, wedge-shaped hot-film probe. Turbulent intensities and macroscale of eddy change in the flow with suspended solid particles on a movable bed is discussed.     

Functional classification of swine manure management systems based on effluent and gas emission characteristics

Gaseous emissions from swine (Sus scrofa) manure storage systems represent a concern to air quality due to the potential effects of hydrogen sulfide, ammonia, methane, and volatile organic compounds on environmental quality and human health. The lack of knowledge concerning functional aspects of swine manure management systems has been a major obstacle in the development and optimization of emission abatement technologies for these point sources. In this study, a classification system based on gas emission characteristics and effluent concentrations of total phosphorus (P) and total sulfur (S) was devised and tested on 29 swine manure management systems in Iowa, Oklahoma, and North Carolina in an effort to elucidate functional characteristics of these systems. Four swine manure management system classes were identified that differed in effluent concentrations of P and S, methane (CH4) emission rate, odor intensity, and air concentration of volatile organic compounds (VOCs). Odor intensity and the concentration of VOCs in air emitted from swine manure management systems were strongly correlated (r2 = 0.88). The concentration of VOC in air samples was highest with outdoor swine manure management systems that received a high input of volatile solids (Type 2). These systems were also shown to have the highest odor intensity levels. The emission rate for VOCs and the odor intensity associated with swine manure management systems were inversely correlated with CH4 and ammonia (NH3) emission rates. The emission rates of CH4, NH3, and VOCs were found to be dependent upon manure loading rate and were indirectly influenced by animal numbers.