Forest biorefineries - A business opportunity for the Finnish forest cluster

Bioenergy and biomass-based products offer the greatest new opportunities for diversifying business in the forest cluster. In particular, biorefineries, which can be integrated into the pulp and paper industry, seem to have immense future potential. This article aims to explore the biorefinery concept and related new products and business operations, as well as new business strategies and company models, which are part of the biorefinery value chain. These factors, which contribute to the establishment and success of forest biorefineries, were examined using internet survey responses and compared between Scandinavia, North America and South America. This article looks at the results of the survey - primarily from the Finnish perspective - to help identify competitive advantages upon which successful business operations in the Finnish forest cluster can be built.According to the survey, the outlooks for technical and raw material choices, as well as barriers to biorefinery diffusion, are very similar in all the studied areas. Biorefineries and related energy products are considered the way to sustainably guarantee the forest cluster’s success. An increase in the price of oil motivates the development of forest biorefineries and wood-based biofuels; however, it is obvious that there is a need to revaluate from a fresh perspective the utilisation of wood and the wood-refining chain in the forest cluster.The survey respondents consider wood-based biofuel and chemical production a serious business opportunity for the forest cluster. In Finland, there is a strong confidence in the production of biofuels. However, all the countries included in the study trust in their own national strengths and in their chance to be a leading actor in the forest biorefinery business worldwide. The forest biorefinery business seems to have market potential, and global competition can thus be expected.     

小风条件下工业园区无组织VOCs溯源方法

为在小风条件下对工业园区周边监测点的无组织VOCs来源进行溯源解析,建立了以烟团积分扩散模型为基础的工业园区无组织VOCs排放溯源模型。通过小风条件下烟团积分扩散模型,计算有组织VOCs排放源对园区下风向监测点的VOCs质量浓度贡献;并结合上风向监测点背景值（VOCs）及下风向监测点质量浓度值（TVOCs）,计算无组织排放源对下风向监测点的质量浓度贡献。根据无组织VOCs排放面源的位置坐标,利用小风条件下烟团积分扩散模型,建立无组织排放源与下风向监测点之间的响应模型;再利用最小二乘法反演出各无组织面源的VOCs排放强度,最后得到VOCs从各无组织排放源到下风向监测点的质量浓度和各监测点的浓度贡献比。在此基础上,推断出各监测点的无组织VOCs来源。溯源结果说明：在监测点S₁,无组织排放源D₁的污染物贡献率为25.71%,D₂的污染物贡献率为5.24%,D₃的污染物贡献率为3.81%;在监测点S₄,无组织排放源D₁的污染物贡献率为14.59%,D₂的污染物贡献率为36.31%,D₃的污染物贡献率为4.83%;在监测点S₁₂,无组织排放源D₁的污染物贡献率为20.17%, D₂的污染物贡献率为0.33%,D₃的污染物贡献率为0.39%。统计结果表明,工业园区无组织VOCs的理论计算值与实际值的误差平方和 R为0.001 5。本研究结果可为小风条件下工业园区无组织VOCs排放溯源解析提供参考。     

Numerical study on the spontaneous ignition of pressurized hydrogen release through a tube into air

Spontaneous ignition of pressurized hydrogen release through a tube into air is investigated using a modified version of the KIVA-3V CFD code. A mixture-averaged multi-component approach is used for accurate calculation of molecular transport. Autoignition and combustion chemistry is accounted for using a 21 step kinetic scheme. Ultra fine meshes are employed along with the Arbitrary Lagrangia–Eulerian (ALE) method to reduce false numerical diffusion. The study has demonstrated a possible mechanism for spontaneous ignition through molecular diffusion.

In the simulated scenario, the tube provided additional time to achieve a combustible mixture at the hydrogen–air contact surface. When the tube was sufficiently long under certain release pressure, autoignition would initiate inside the tube at the contact surface due to mass and energy exchange between low temperature hydrogen and shock-heated air through molecular diffusion. Following further development of the hydrogen jet downstream, the contact surface became distorted. Turbulence plays an important role for hydrogen/air mixing in the immediate vicinity of this distorted contact surface and led the initial laminar flame to transit into a stable turbulent flame.     

瓦斯气体在煤层中的扩散机理及模式

根据气体在多孔介质中的扩散模式 ,结合煤结构的实际特点 ,分析了瓦斯气体在煤孔隙中的扩散机理 ,得出瓦斯在煤体中几种扩散模式 :菲克型扩散、诺森扩散、过渡型扩散、表面扩散和晶体扩散。从微观上看 ,影响瓦斯气体在煤层中扩散的主要因素是瓦斯气体的平均自由程和煤不同尺寸微孔隙的分布情况。根据不同孔隙分布的煤层 ,探讨了各种扩散模式的适用条件     

DETERMINATION OF DDT AND ITS METABOLITES IN CATTLE DIP SOIL AVAILABLE IN AQUEOUS PHASE AFTER REMEDIATION

Soil taken from a former cattle tick dip site in NSW Australia, was remediated with a chemical leaching technology. The pre- and post-remediated soil (20g) was dispersed in water (100mL) and subjected to passive diffusion using polymeric membranes. The remediation reduced tDDT from 1174.3μg/g to 102.9μg/g (ash weight basis), which was further reduced to 43.2μg/g with composting. The membranes accumulated 41.3μg tDDT/g from the dip soil, 49.2μg tDDT/g from the chemically leached soil and 3.1μg tDDT/g from the leached composted soil. The chemical leaching removed over 90% of the tDDT, but released soil bound DDT, which was converted to DDE, while 2.99μg/g was accumulated by the membranes from dip soil, 37.52μg/g was accumulated from remediated soil. Composting, however, almost eliminated the availability for passive diffusion by the membranes from 50 – 60μg/g in remediated soil to 3–3.5μg/g in composted soil. Variability studies of the membranes using eight replicates demonstrated that the accumulation by the membranes was reproducible with an average relative error of 20.3% for p,p'-DDT in soil type two, whilst the lowest average relative error for p,p'-DDE was 4.3%, suggesting that triplicate analyses will achieve acceptable accuracy.     

基于信息扩散理论的江苏省酸雨风险评估

利用江苏省2008-2013年24个站的酸雨监测资料,分析出2008-2013年江苏省酸雨的强度和发生频率都有下降趋势,秋冬季酸雨发生频率高,夏季最低。基于信息扩散理论对全省酸雨进行风险评估,结果发现:年降水p H值和酸雨发生频率在不同风险水平分布特征较为一致,呈西北-东南逐渐增强趋势;年降水p H值80%的可能介于4.5~5.6之间,呈弱酸性;淮河以南地区酸雨发生频率的风险为40%的概率超过90%。     

Effects of pore size and dissolved organic matters on diffusion of arsenate in aqueous solution

Presented here is the influence of membrane pore size and dissolved organic matters on the diffusion coefficient(D) of aqueous arsenate, investigated by the diffusion cell method for the first time. The p H-dependent diffusion coefficient of arsenate was determined and compared with values from previous studies; the coefficient was found to decrease with increasing p H, showing the validity of our novel diffusion cell method. The D value increased dramatically as a function of membrane pore size at small pore sizes, and then increased slowly at pore sizes larger than 2.0 μm. Using the Exp Assoc model, the maximum D value was determined to be 11.2565 × 10~-6cm~2/sec. The presence of dissolved organic matters led to a dramatic increase of the D of arsenate, which could be attributed to electrostatic effects and ionic effects of salts. These results improve the understanding of the diffusion behavior of arsenate, especially the important role of various environmental parameters in the study and prediction of the migration of arsenate in aquatic water systems.     

锶在水中的扩散参数研究

扩散参数是影响物质在水中迁移的一个比较重要的参数，本论文通过自己设计的扩散装置，采用^87Sr(NO3)2作为示踪剂研究了锶元素在水环境中的扩散参数，同时还从理论计算上对试验结果进行了验证。     

An individual-based stochastic hazard model of eastern king prawn (Melicertus plebejus) migration with spatially and temporally varying fishing effort

This paper describes an individual-based stochastic model of eastern king prawn migration along the eastern Australian coast. Migration is treated as one-dimensional diffusion with drift. Capture of a prawn is seen as a failure event driven by movement through a spatially and temporally variable fishing mortality hazard. This hazard is combined with a uniform natural mortality hazard. We use a Monte Carlo method to estimate parameters by comparing expected numbers of tag-returns predicted from the model with previously published tag-release data. As the previous study used a discrete compartmental model, with compartments corresponding to zones of constant fishing effort, we used the same zones and fishing effort in our comparison. The marginal distribution of yield in each zone per single recruit is determined, providing more information compared with the deterministic approach to yield-per-recruit. Using our model we also derive the constant fishing mortality rate equivalent to a spatially variable fishing mortality rate in its impact on the proportion of prawns surviving the migration to reach spawning grounds. Determination of this proportion could contribute significantly to a sustainability assessment of the fishery. It is demonstrated using the AIC that better fits to the data of the previous study and greater parsimony are obtained using our model than were found in the deterministic compartmental analysis of that study. This improvement results from the ability of our model to account separately for average speed of movement and average dispersal rate, whereas in the previous deterministic compartmental model, movement is governed by just one parameter. Our individual-based model includes a parameter that explicitly accounts for dispersal of prawns in migration, so it can distinguish between speed effects and dispersal effects in the data. It also models both types of mortality as processes distinct from those of movement. This enables it to better separate movement and mortality effects compared to the compartmental approach, in which movement and mortality are treated as similar departure processes from a compartment. This separation reduces confounding of movement and mortality effects when parameters are estimated.     

Density-dependent kinetics models for a simple description of complex phenomena in macroscopic mass-balance modeling of bioreactors

From experiments originally proposed by Ardity et al. [Arditi, R., Perrin, N., Saïah, H., 1991. Functional responses and heterogeneities: an experimental test with cladocerans. Oikos 60, 69–75] in the field of fundamental ecology, this paper derives conditions under which mass balance ratio-dependent kinetics models are more appropriate (in a sense to be specified in the sequel) than substrate-dependent kinetics models to macroscopically describe bioprocesses with attached biomass. From literature results, it is also suggested that the use of Contois growth functions should be preferred to substrate-dependent kinetics when macroscopically modeling an immobilized-biomass bioreactor. The “robustness” of this result, rather based on a qualitative reasoning, is investigated in simulation and a number of fundamental properties of ratio-dependent models are highlighted. Furthermore, it is shown that ratio-dependent models are well suited to describe macroscopically bioreactors where the diffusion phenomenon is obviously one of the most important limiting factor.