A numerical study on the design trade-offs of a thin-film thermoelectric generator for large-area applications

Thin-film thermoelectric generators with a novel folding scheme are proposed for large-area, low energy-density applications. Both the electrical current and heat transfer are in the plane of the thermoelectric thin-film, yet the heat transfer is across the plane of the module - similar to conventional bulk thermoelectric modules. With such designs, the heat leakage through the module itself can be minimized and the available temperature gradient maximized. Different from the previously reported corrugated thermoelectric generators, the proposed folding scheme enables high packing densities without compromising the thermal contact area to the heat source and sink. The significance of various thermal transport, or leakage, mechanisms in relation to power production is demonstrated for different packing densities and thicknesses of the module under heat sink-limited conditions. It is shown that the power factor is more important than ZT for predicting the power output of such thin-film devices. As very thin thermoelectric films are employed with modest temperature gradients, high aspect-ratio elements are needed to meet the - usually ignored - requirements of practical applications for the current. With the design trade-offs considered, the proposed devices may enable the exploitation of thermoelectric energy harvesting in new - large-area - applications at reasonable cost.Comment: 26 pages,5 figures, post-peer-review, pre-copyedit version of an article published in Renewable Energ

Consumer values and eco-fashion in the future

This paper discusses the consumer values, attitudes and expectations regarding sustainable textiles and clothing. Consumers' interest in ethical issues is currently raising ethical questions in the mass market. What does a consumer expect from sustainable products in the apparel industry? and what is future eco-fashion

Knowledge spillovers – Mobility of highly educated workers within high technology sector in Finland

The economic development and technological progress of a region are highly dependent on the accumulation and diffusion of knowledge. There are numerous channels through which knowledge might be transmitted. In this study, it is assumed that regional mobility of highly educated and innovative intensive workers between firms, organisations or institutions secures the diffusion and circulation of the knowledge. Hence, this analysis will concentrate on the regional job flows of individuals working in the high technology sector. The main topics of interest are: (1) to analyse the personal and household characteristics of the typical highly educated migrants within high technology sector, and (2) to evaluate the rate of labour turnover in different sub-sectors and regions. The empirical analysis of the paper is based on data from the Finnish Longitudinal Census File. Methodologically, the worker flows between regions are modelled by the maximum likelihood estimation which employs cross-sectional binary logit model, based on logistic distribution.

Agglomeration economies in the Finnish manufacturing sector

Regional concentration of population and economic activity is a common phenomenon both in Finland and the other most developed countries, which refers to the existence of agglomeration economies. Two types of economies are usually recognised to be important: specialisation (Marshall externalities) and diversity (Jacobs externalities) economies. The former refer to the geographical concentration of a specific industry and the latter to the industrial diversity of the local system. This paper examines the relationship between agglomeration economies and regional productivity in the manufacturing sector in Finland. A distinction is made between the effects of urbanisation and localisation economies. The production function method is applied to the manufacturing sub-sectors in the 83 NUTS 4-level regions in 1995 and 1999. The results find in favour of regional specialisation more than diversification even if some differences can be seen between the manufacturing sub-sectors. Localisation economies seem to be stronger in the regions where the average size of firms is small, which indicates that regions with smaller firms might profit more from localisation.

Exploitation of Transparent Conductive Oxides in the Implementation of a Window-Integrated Wireless Sensor Node

Exploitation of transparent conductive oxides (TCO) to implement an energy-autonomous sensor node for a wireless sensor network (WSN) is studied and a practical solution presented. In the practical implementations, flexible and rigid substrates that is polyimide and glass, are coated with TCO, namely aluminum doped zinc oxide (AZO). AZO-coated flexible substrates are used to form thermoelectric generators (TEG) that produce electricity for the sensor electronics of the node from thermal gradients on a window. As the second solution to utilize AZO, its conductive properties are exploited to implement transparent antennas for the sensor node. Antennas for a UHF RFID transponder and the Bluetooth radio of the node are implemented. A prototype of a flexible transparent TEG, with the area of 67 cm2 when folded, was measured to produce power of 1.6 uW with a temperature difference of 43 K. A radiation efficiency of -9.1 dB was measured for the transparent RFID antenna prototype with the center frequency of 900 MHz. Radiation efficiencies between -3.8 dB and -0.4 dB, depending on the substrate, were obtained for the 2.45 GHz Bluetooth antenna.Comment: 10 pages, 14 figures, last author version accepted for publication in IEEE Sensors Journa

Role of regional policies in promoting networking and innovation activity of firms

The success of firms and regions is increasingly defined by their innovation and learning capabilities. It has been emphasized in several studies that a local operational environment may have a positive impact on innovation activity of firms. From policy point of view, the relationship between firms and their local environment is an important research topic. The purpose of this paper is to explore whether there is a demand for regional policy makers in promoting innovative and networking activity of firms, and what are the appropriate strategies in this regard. The concept of innovative milieu provides a theoretical base for this study. The data used is based on personal interviews representing 30 high tech firms located in Jyväskylä Science Park in Finland. The results show that the firms appreciate an individual-level approach by policy makers which enables them to take the real needs of firms into consideration. A developed service structure, that is planned to meet the demand of new and established firms as well as possible, is an essential part of the well functioning operational environment. Supporting contacts with service providers and experts from different fields and organizing collective meetings for firms are important targets for the policy makers. In the innovation process, a commercial view of external part is considered very crucial. The small advances which alternate between the development of the innovation process and networks among firms and their interest groups could form a favourable path towards an operational environment with efficient innovative networks.

Feeding value of red clover-grass, Persian clover and common vetch for pigs

Red clover-grass, Persian clover, and common fetch that are generally grown for green manuring in organic cropping cycles, are also valuable forages for the feeding of pigs. They could substitute up to 30% of concentrates (on dry matter basis) in the feeding of growing pigs without negative impact on nitrogen (N) retention. This indicates that protein and amino acids of these legumes are well digested and utilised by the pigs. However, inclusion of roughage to pig diets shifts N utilisation so that N excretion to faeces is increased while N excretion to urine is decreased. Persian clover, in particular, is an intriguing roughage for pigs as its protein contains more amino acids that that of red clover-grass or common vetch. In addition, the digestibility of fibre is good in Persian clover, due to lower cellulose and lignin content in the fibre fraction. In practice, the voluntary feed intake of roughages remains lower, from 5% to 20% of pigs’ dry matter intake depending on the production phase

Feeding weaned piglets and growing-finishing pigs with diets based on mainly home-grown organic feedstuffs

In 2000, EU regulations for organic animal production set new guidelines for organic pig feeding requiring that this be based on mainly home-grown organic feedstuffs. Doubts were however raised whether these feeding regimes can maintain good growth performance and carcass quality of pigs. Three experiments were carried out to study different organic feeding regimes in weaned piglets and fattening pigs. In Experiment 1, we evaluated the use of peas and faba beans (0, 120, or 240 g kg-1) in diets for weaned piglets. Piglets fed pea diets performed as well as those fed the control diet, whereas the highest faba bean level resulted in reduced feed intake and growth performance. In Experiment 2, we studied the replacement (0, 33, or 67%) of rapeseed cake with blue lupins in fattening pig diets. The dietary lupin level had a quadratic effect on the weight gain of growing pigs, the best performance being observed at the 33% replacement level. However, dietary lupin level did not influence weight gain during the finishing period and total fattening. Back fat became softer with increasing dietary lupin levels. In Experiment 3, different protein supplements were compared in organic diets from weaning to slaughter. In two-phase feeding, the best performance was observed when whey protein was used as the protein supplement, followed by soya bean cake + whey protein and rapeseed cake + fish meal. The effects of a one-phase organic feeding regime with cold-pressed rapeseed cake + whey protein did not differ from those of the two-phase organic feeding regimes. Fattening pigs fed organic diets required from two to seven days longer to reach slaughter weight than those fed conventional diets. Pigs fed organic diets had fatter carcasses, but the eating quality of organic pork did not differ from that of pork from pigs fed conventional diets. Feed costs and the circulation rate of pigs, weaners in particular, were greater and carcass prices lower in the organic feeding regimes than in the conventional ones

Sensitivity of soil phosphorus tests in predicting the potential risk of phosphorus loss from pasture soil

The objective of this study was to examine the effects of urine and dung additions on the phosphorus (P) chemistry of pasture land and to compare the sensitivity of two soil extraction methods in assessing the P-loading risk. In a field experiment, urine and dung were added to soil in amounts corresponding to single excrement portions and the soil samples, taken at certain intervals, were analysed for pHH2O, acid ammonium acetate extractable P (PAc) and water extractable total P (TPw), and molybdate reactive P (MRPw). Urine additions immediately increased soil pH and MRPw, but no such response was observed in PAc extraction due to the low pH (4.65) of the extractant enhancing the resorption of P. The PAc responded to the dunginduced increase in soil total P similarly as did Pw, which suggests that both tests can serve to detect areas of high P concentration. However, water extraction was a more sensitive method for estimating short-term changes in P solubility. In pasture soils, the risk of P loss increases as a result of the interaction of urination and high P concentration in the topsoil resulting from continuous dung excretion