خيارات البحث
النتائج 81 - 90 من 126
Research of 'duration of load' effects in timber elements in bending
2012
Brokans, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The Duration of Load (DOL) effect is the combined influence of the mechanical loading history and climatic history on the strength of materials. DOL effect is one of the most important characteristics of wood and wood-based materials. The material degradation or damage induces strength reductions. Creep is one of the most important effects of DOL. Creep is a phenomenon that negatively affects functional compliance, behaviour and strength of timber structures in extended years of exploitation. The creep phenomenon is affected by surrounding temperature, relative humidity, timber moisture content and other factors. The study aimed to establish a correct factor system for accurate prediction of long-term deformations of timber structures that is corresponding to environmental conditions and timber properties in the region of Latvia. The experimental research was made in Jelgava, Latvia, and represents timber beam four-point long-term loading in bending with variable cross section height-span length ratio under uncontrolled climatic conditions. There were 12 timber beams with two different span lengths – 1.32 m and 1.50 m used. The timber beam cross section dimensions: height – 60 mm, width – 30 mm. The timber beams were not dried and the moisture content at the start of the experiment varied from 19% to 33%. The applied load values – 0.40 kN and 0.31 kN. Moisture content fluctuations and negative air temperature accelerated creep development and intensity. Prediction of final long-term deformations should rate not only the type of timber material and service class but the strength class, too.
اظهر المزيد [+] اقل [-]Regulated streams rehabilitation using bioengineering methods
2012
Maziliauskas, A., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Baublys, R., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Geguzis, R., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
Within several decades many natural Lithuanian rivers were straightened and adapted for needs of soil drainage. By 1998, 63.4 thousands kilometres of trenches of which approximately 46 thousands kilometres were regulated rivers and streams were excavated. It is calculated that trenches of regulated rivers and streams currently cover 82.6, and natural – only 17.4% of total rivers network. While straightening rivers, their channels were extended, their slopes were changed, and bends were removed. Thus, it ensured a fast removal of excess water from drained areas of ground. However, as in the straightened rivers an equal stream was present, unfavourable conditions arouse for ichthyofauna, as well as for settlement and evolution of the invertebrates. Furthermore, possibilities for selfpurification of water running through the channel were reduced. In order to restore morphological, hydraulic, and especially ecological conditions, close to natural ones, of the straightened rivers, it is necessary to renaturalize them. The analysis of river naturalization and renaturalization ways and means was performed on the basis of the reviewed projects carried out in foreign countries. Four renaturalization methods were identified: self-naturalization, soft naturalization, partial and full renaturalisation. The possibility to use these naturalization methods were evaluated taking into account environmental conditions of Lithuania. The analysis of naturalization projects implementation showed that the best way to rehabilitate Lithuania‘s straightened rivers is to use partial renaturalization method that lets form more favourable ecological environment of rivers. The object of the research was - to evaluate the most suitable naturalization methods for Lithuanian conditions.
اظهر المزيد [+] اقل [-]Churchyard elements in Latgale Upland [Latvia]
2012
Markova, M., Latvia Univ. of Agriculture, Jelgava (Latvia)
Churchyard of Latgale Upland is one of the most important parts of cultural historic space of Latvia. The study is based on the materials from expedition made in summer and autumn 2011, as well as on literary studies. Architecturally compositional form of the church is a key part of the landscape, supplemented by other landscape elements. Research and evaluation of the individual elements give specific cultural space characteristics of each investigated area. Visibility in the main view points and links with residential buildings for the churchyard is vital. Each study of landscape area schemes formation is based not only on the church as a domination point expression. Separate churchyard elements - crucifixes, procession paths, burial area, meditation area and a planting in church gardens - are important in describing churchyards. The aim of the research was to find most common elements in churchyards to establish general guidelines for recording and evaluation of the churchyard in Latgale Upland in future. In perspective that could be used as basis for making the landscape typology. Results showed typical landscape elements in the churchyard. In describing churchyards is important to divide typical and unique elements. The research provides information that is important for the further local territorial development plans, focusing attention on the region’s cultural values and identity preservation.
اظهر المزيد [+] اقل [-]Probability distributions of wave heights in the Lithuanian coast
2012
Kasiulis, E., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
Since discovering that signals of random waves submit to the known laws of probability, this became widely used in engineering and energetics for probability distributions analysis of wave height. From an energetic point of view, it is necessary to know the average wave height in, for example, highly wavy (1% probability), medium wavy (25% probability) or non-wavy (95% probability) years. Whereas, maximum multi-year value of wave height characteristics is essential for engineering resistant wave energy converters that could withstand severe marine conditions. Average and maximum annual values of wave height data collected from Klaipėda coastal hydrometeorological station are used for this study. Probability distributions of average and maximum wave heights in the Lithuanian coast are analyzed in this paper. The best fitting is obtained using HYFRAN and EASY FIT software. Both, a test for independence (Wald- Wolfowitz) and stationarity test (Kendall) are carried out for every time series using HYFRAN software. Maximum like hood method is selected for distribution estimation. Fitting is determined using chi-square test and the best fitting is verified with comparison (BIC and AIC) criterion. Fitting for one of the most commonly used distributions in the analysis of wave climate – Rayleigh distribution – cannot be determined with HYFRAN software. For this purpose, EASY FIT software is used additionally. The fit of the distribution is evaluated via the chi-square test similarly. Calculated wave heights based on lognormal probability distribution that fits best according to HYFRAN software are similar to those calculated using Rayleigh probability distribution.
اظهر المزيد [+] اقل [-]Financial distress determinants: the survey of Lithuanian farms
2012
Stulpiniene, V., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Alekneviciene, V., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
Farm financial distress can be determined by many factors. Farm failure can be the result of macroeconomic environment, unsuccessful farmer’s management decisions, and even natural forces. Different financial distress determinants may have different influence on a farm financial position. This study presents average financial ratios (leverage, return on assets, and return on equity) and single ratio of rental equivalent to gross margin according to farm size, land quality, economic size, farmer’s age and type of farming in Lithuania. The new approach to financial distress diagnosis requires classifying farms into financial positions. Considering average financial ratios and single ratio of rental equivalent to gross margin, farms were classified according to financial positions in order to estimate these methods’ suitability for financial distress diagnoses. Using study results, farmers can identify their position according to the average ratios. This study could be a guide for farmers making the financial management decisions.
اظهر المزيد [+] اقل [-]Perspective of sustainable food consumption in Latvia
2012
Dzene, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Eglite, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Food consumption becomes an increasingly important topic considering global and local environmental problems as well as health issues and wellbeing of nations in general. Also in Latvia people are becoming more aware of importance of food and its direct and indirect impact on their everyday life. Therefore it is very important to evaluate sustainable aspects of food consumption and look for the barriers and drivers in order to form more sustainable consumption patterns which are based on information, knowledge and consciousness. The aim of the study is to investigate the perspective of sustainable food consumption in Latvia. The tasks of the study are: 1. to review present food consumption patterns from sustainability perspective; 2. to elucidate consumers’ understandings, attitudes and behaviour towards sustainable food consumption. The empirical research was based on the online survey with a sample of 82 women in the age group from 19-35. Descriptive statistics were used to analyze the results of the questionnaire and data obtained from Central Statistical Bureau of Latvia. The results of the study indicate the gap between positive attitudes towards sustainable food and stated purchasing behaviour. There is an obvious perspective of growth of sustainable food market if we increase the awareness of consumers regarding sustainable consumption issues.
اظهر المزيد [+] اقل [-]Estimation of potential impact of coastal erosion protection in Latvia
2012
Brunina, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Konstantinova, E., Information Systems Management Inst., Riga (Latvia)
The Baltic Sea problems in context of erosion always have been very topical and since ancient times have been caused by uncontrollable and unpredictable natural factors (storms). These factors combine with the impact of human economic activities of the direct effect of factors -building offshore and aquatorium, deficit of sediment and marine dredging and growth of recreational tourism growth that promote load of coastal vegetation and dune relief. The identification of costs and benefits is significant step for evaluation of the impact of the Project and usefulness of the costs. The positive impact or benefits can occur at once, after a while or long term perspective. The economic evaluation techniques particularly cost-benefit and cost-effectiveness analysis for coastal protection in this case used for ascertain the most effective alternative. The sensitivity analysis was made for verifying impact of alternatives on taken solution. The aim of research is to verify the economic methods for application to coastal management in Latvia. The world’s coastal scientists believe that the future of coastal policy will become increasingly polarized and discussed; therefore, gradual implementation of the assessment process and development of socio-economic indicators is recommended.
اظهر المزيد [+] اقل [-]Current situation of cavy production in Cameroon: Challenges and opportunities
2012
Niba, A.T. | Meutchieye, F. | Fon, D. | Laisin, A.G. | Taboh, H. | Njakoi, H. | Bela Tomo, A. | Maass, Brigitte L. | Djikeng, Appolinaire | Manjeli, Y.
The review looks at the current status of cavy production in Cameroon and situates cavy culture in the area of their contribution to meat production, income generation for cavy farmers in Cameroon. It also reviews research and development of cavy culture in Cameroon. It indicates that cavy culture is an affordable way out of malnutrition for rural women and their families as well as a sustainable way of income generation for these women. It highlights the work done by the various promotion agencies like Heifer international Cameroon and the programme for the support of non-conventional livestock production (PAPENOC) in capacity building for cavy farmers as well as providing material support (improved animals, forage resources and veterinary care). It stresses the need for capacity building for cavy farmers as a means of promoting cavy culture in Cameroon and summarises present and past student/staff research on cavies at the Faculty of Agronomy and Agricultural Sciences, University of Dschang in collaboration with the Institut de Recherches Zootechniques et Vétérinaires (presently Institute of Research for Agricultural Development-IRAD). Development needs are also summarised in the challenges for research on breeding and selection, nutrition, animal health and management practices. The paper indicates that cavy production in Cameroon will have a face lift as a new project on ‘Harnessing husbandry of domestic cavy for alternative and rapid access to food and income in Cameroon and the eastern Democratic Republic of the Congo’ has been implemented since early 2012. It concludes that this project offers a golden opportunity to move the agenda for domestic cavy production forward in Cameroon.
اظهر المزيد [+] اقل [-]Aviculture familiale au Bas-Congo, République Démocratique du Congo (RDC) | Village poultry in Bas-Congo, Democratic Republic of Congo (DRC)
2012
Moula, Nassim | Detiffe, Nicolas | Farnir, Frédéric | Antoine-Moussiaux, Nicolas | Leroy, Pascal | Département des productions animales, Faculté de Médecine vétérinaire, Université de Liège,
peer reviewed | La République Démocratique du Congo (RDC) souffre, à l’instar d’une majorité de pays africains, d’une précarité alimentaire conséquente. Le développement du secteur de l’élevage y est une pièce importante de la stratégie de lutte contre cette insécurité alimentaire, par l’apport de protéines de haute qualité aux populations pauvres ainsi que plus globalement par la création de richesses et la diversification du secteur agricole. A ce titre, le secteur avicole offre incontestablement, par son cycle de production court, une solution rapide et abordable par le plus grand nombre. Cette étude aborde les contraintes à la production de la poule locale au Bas-Congo. Plusieurs facteurs y sont identifiés, tels que les pathologies, l’alimentation, l’habitat et les prédateurs. L’amélioration de la situation économique et nutritionnelle des paysans de la Province du Bas-Congo peut être envisagée en améliorant le potentiel de production des poulets de race locale. Afin d’y arriver, une attention particulière doit être accordée à une alimentation équilibrée et une meilleure conduite générale de l’élevage, incluant un accès aux soins vétérinaires. L’amélioration génétique des races locales est également une voie envisageable, pour autant que l’adéquation entre l’animal et le cadre de son élevage soit respectée.
اظهر المزيد [+] اقل [-]A cross-sectional survey on fasciolosis in selected settlements of Taveta Division, Coast Province, Kenya
2012
Mungube, E.O. | Sila, D.M. | Kariuki, C.W. | Bauni, S.M. | Tenhagen, B.-A. | Wamae, L. | Nginyi, J. | Omondi, G.A.
A cross-sectional survey on fasciolosis was conducted in March 2009 in Taveta Division. Bura Ndogo, Challa, Kiwalwa, Kitogoto and Lake Jipe Gicheha settlements participated in the study. A total of 338 (197 cattle, 111 goats and 30 sheep) faecal samples from 42 herds were examined using the sedimentation technique. Similarly, husbandry practices and aspects of herd owner education in the same settlements were captured using a standard questionnaire. Selective deworming targeted at the sick and /or weak looking animals was done by some herd owners interviewed. Fasciolosis prevalence in cattle, goats and sheep was 25.9%, 23.4% and 33.3%, respectively. Extensive grazing and age stratum 7 - 12 months were identified as potential fasciolosis risk factors with the latter being significantly (p<0.05) associated with the disease. On the contrary, home watering, training on livestock husbandry practices and deworming were significant (p< 0.05) protective factors of fasciolosis. Improved husbandry practices assisted by the selective anthelmintic treatments targeting the young animals were identified as feasible fasciolosis control options for Taveta division. In conclusion, the results of the study have clearly shown that fasciolosis is widespread in Taveta Division making it necessary for further longitudinal studies on the disease for establishment of an effective control programme
اظهر المزيد [+] اقل [-]