Mitigating grid voltage harmonics using a line converter with active filtering feature

A line converter equipped with an LCL-line filter is used as an active filter directly compensating grid voltage harmonics. The control of four individual grid voltage harmonics is implemented using an individual control of corresponding harmonic line currents. The knowledge of the grid impedance is essential to efficient control of the grid voltage harmonics. To overcome the problem of an unknown grid impedance an identification method is used. The method uses the converter control system to measure the grid impedance at selected frequencies. The active voltage harmonic cancellation is tested with a 19 kVA line converter by compensating background voltage distortion and distortion caused by a nonlinear load.     

Experiences in developing mobile applications using the Apricot Agent Platform

The trend of increasing mobile services has set a new challenge for service providers: how to develop more advanced and user-friendly, context-aware and personalized mobile services for the users. Apricot Agent Platform is an agent-based software platform designed for developing context-aware and personalized mobile services. Apricot Agent Platform supports the development of user-friendly mobile services by providing tools for combining various mobile and Internet-based services. Apricot agent architecture consists of an agent platform, agents and agent containers. For the developers of mobile services, it provides built-in functionality and communication mechanism. Furthermore, this paper describes four demonstrators that are built up on the Apricot Agent Platform to evaluate the usability and efficiency of the platform in the processes of building mobile services. The outcome of the evaluation indicates relatively promising results and the further target for development is revealed.     

Expression of ion transport-associated proteins in human efferent and epididymal ducts

Appropriate intraluminal microenvironment in the epididymis is essential for maturation of sperm. To clarify whether the anion transporters SLC26A2, SLC26A6, SLC26A7, and SLC26A8 might participate in generating this proper intraluminal milieu, we studied the localization of these proteins in the human efferent and the epididymal ducts by immunohistochemistry. In addition, immunohistochemistry of several SLC26-interacting proteins was performed: the Na(+)/H(+) exchanger 3 (NHE3), the Cl(-) channel cystic fibrosis transmembrane conductance regulator (CFTR), the proton pump V-ATPase, their regulator Na(+)/H(+) exchanger regulating factor 1 (NHERF-1), and carbonic anhydrase II (CAII). Our results show that SLC26A6, CFTR, NHE3, and NHERF-1 are co-expressed on the apical side of the nonciliated cells, and SLC26A2 appears in the cilia of the ciliated cells in the human efferent ducts. In the epididymal ducts, SLC26A6, CFTR, NHERF-1, CAII, and V-ATPase (B and E subunits) were co-localized to the apical mitochondria rich cells, while SLC26A7 was expressed in a subgroup of basal cells. SLC26A8 was not found in the structures studied. This is the first study describing the localization of SLC26A2, A6 and A7, and NHERF-1 in the efferent and the epididymal ducts. Immunolocalization of human CFTR, NHE3, CAII, and V-ATPase in these structures differs partly from previous reports from rodents. Our findings suggest roles for these proteins in male fertility, either independently or through interaction and reciprocal regulation with co-localized proteins shown to affect fertility, when disrupted.     

Molecular dynamics studies on the thermostability of family 11 xylanases

Twelve members of the family 11 xylanases, including both mesophilic and thermophilic proteins, were studied using molecular dynamics (MD). Simulations of xylanases were carried out in an explicit water environment at four different temperatures, 300, 400, 500 and 600 K. A difference in thermotolerance between mesophilic and thermophilic xylanases became clear: thermophilic xylanases endured heat in higher simulation temperatures better than mesophilic ones. The unfolding pathways seemed to be similar for all simulations regardless of the protein. The unfolding initiates at the N-terminal region or alternatively from the alpha-helix region and proceeds to the 'finger region'. Unfolding of these regions led to denaturated structures within the 4.5 ns simulation at 600 K. The results are in agreement with experimental mutant studies. The results show clearly that the stability of the protein is not evenly distributed over the whole structure. The MD analysis suggests regions in the protein structure which are more unstable and thus potential targets for mutation experiments to improve thermostability.     

Optical detection of the anesthetic agent propofol in the gas phase

The anesthetic agent propofol (2,6-diisopropylphenol) is the most widely used intravenously administered drug in general anesthesia. However, a viable online capability to monitor metabolized levels of propofol in patients does not currently exist. Here we show for the first time that optical spectroscopy has good potential to detect metabolized propofol from patients' exhaled breath. We present quantitative absorption measurements of gas phase propofol both in the ultraviolet and middle-infrared spectral regions. We demonstrate that a detection limit in the subparts-per-billion concentration range can be reached with photoacoustic spectroscopy in the UV spectral region, paving the way for the development of future optical monitors.     

Achieving global environmental benefits through local development of clean energy? The case of small hilly hydel in India

Energy and development are closely intertwined. Yet, increasing fossil fuel-based energy consumption contributes significantly to environmental problems both locally and globally. This article explores the interlinkages between local livelihood and environmental benefits from the provision of energy to remote rural households through small hydropower development. The analysis is based on research carried out around a large development project designed to assist the Government of India in the optimum utilization of small hydropower resources in the Himalayan and sub-Himalayan regions. There are about 100,000 villages in India that are not connected to electricity supply, many of them in the hilly regions with ample hydropower potential. The project aimed to demonstrate the utility of and options for providing electricity to such villages through clean mini-hydro. The article addresses the nature of the impacts of the demonstration small hydel schemes on the local communities, to what extent they translate into environmental benefits both locally and globally, and the perceptions and participation of the local communities in these small hydro schemes. The study explores the impacts of the schemes on financial capital, natural capital, social capital, physical capital, human capital, and gender equity in the local communities. It further provides a discussion on the links between local and global environmental benefits. Overall, it is found that the schemes’ impacts both on the local communities and the environment are mostly marginally positive or neutral, although achieving clearly demonstrable benefits would require major upscaling of the effort involving broader changes than possible under this project. Furthermore, it is argued that some of the assumptions behind the project design were faulty. Involvement of the local communities and direct livelihood benefits to them are essential for the long-term sustainability of the small hydro schemes. The discussion and conclusions are intended to provide guidance to programmes and projects that aim to promote environmentally sound energy in the rural areas of developing countries.     

Cost-optimal energy performance measures in a new daycare building in cold climate

New municipal service buildings must be energy effective, and cost-optimality is one of the criteria for selecting the suitable energy performance improvement measures. A daycare building in a cold climate was studied by means of simulation-based, multi-objective optimisation. Using a genetic algorithm, both target energy use and life-cycle cost of the selected measures were minimised. It was found that extensive insulation of the building envelope is not a cost-optimal method to reduce the daycare building energy use. Improving energy efficiency of the ventilation system, utilising solar energy on-site and employing a light control strategy are preferable ways of improving the building energy performance. Ground-source heat pump is a more cost-optimal heating system for the daycare building than district heating. The cost-optimal sizing of the heat pump is small, only 28% of the required maximum heating power.

Abbreviations: AHU: air handling unit; CAV: constant air volume; COMBI: comprehensive development of nearly zero-energy municipal service buildings; COP: coefficient of performance; DH: district heating; DHW: domestic hot water; EPBD: energy performance of buildings directive; EU: European Union; FINVAC: Finnish Association of HVAC Societies; GSHP: ground-source heat pump; HRU: heat recovery unit; IDA ICE: IDA Indoor Climate and Energy; LED: light-emitting diode; MOBO: multi-objective building optimisation tool; NSGA-II: Non-dominated Sorting Genetic Algorithm II; nZEB: nearly zero-energy building; PV: photovoltaic; TRY: test reference year; VAV: variable air volume; ZEB: zero-energy building     

Control of swelling properties of polyvinyl alcohol/hyaluronic acid hydrogels for the encapsulation of chondrocyte cells

Hydrogel scaffolds for tissue engineering are important biomaterials. The target in this study was to prepare polyvinyl alcohol/hyaluronic acid hydrogels for the encapsulation of chondrocyte cells by a simple cross‐linking reaction. Control of the swelling properties and morphology of the hydrogels for cultivation of chondrocytes was studied. The hydrogels were prepared from polyvinyl alcohol and hyaluronic acid derivatives bearing primary amine and aldehyde functionalities, respectively. The formation of the hydrogel upon mixing the aqueous solutions of the polymer derivatives took place at room temperature in a few seconds. The swelling properties of the hydrogels were found to depend on the polymer concentration and degree of substitution of the modified polymers. Scanning electron microscopy studies showed that the hydrogels had a suitable porous morphology for cell encapsulation. Furthermore, in vitro cell viability tests with the hydrogels showed no cytotoxicity for chondrocytes and that the cells grew well in the hydrogel scaffolds. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42272.     

Predicting effects of exploitation rate on weight-at-age, population dynamics, and bioaccumulation of PCDD/Fs and PCBs in herring (Clupea harengus L.) in the Northern Baltic Sea

The Baltic Sea ecosystem and fish stocks contain high concentrations of environmental chemicals such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs). This study forecasts how changes in fishing or natural mortality would probably influence concentrations of PCDD/F and PCB in the Bothnian Sea (Northern Baltic) herring (Clupea harengus L.). An age-structured simulation model was developed to forecast herring stock dynamics, catches, and weight-at-age under different assumptions about exploitation and natural mortality. The simulated herring weight-at-age estimates were employed in a bioenergetics model capable of simultaneous estimation of bioaccumulation of 17 PCDD/F and 37 PCB congeners. Although the natural variability in recruitment greatly influences the stock dynamics, considerable changes in weight-at-age would ensue changes in exploitation rate or in natural mortality rate. If exploitation rates increase, growth rates would be higher and herring in the weight categories of commercial fisheries would be younger and contain less PCDD/F and PCB. Hence, the average toxicant concentrations in catches would also decline. However, it is likely that only fairly small changes would occur in toxicant concentrations-at-age. On the other hand, a drastic decrease in herring fishing would substantially increase PCDD/F and PCB concentrations in herring. The study indicated that, in spite of the clear influences of fishing on the toxicant concentrations, fishing alone cannot resolve the problems associated with a high concentration of toxicants in herring; further decreases in loading are still required.