Search results for "Protection"
showing 10 items of 1623 documents
A New Solution for Low-Voltage Distributed Generation Interface Protection System
2015
In this paper, a new solution is proposed for the remote monitoring and control of distributed generators (DGs) and energy storage systems (ESSs) connected to low-voltage distribution networks. The proposed system fulfills the in-force standard requirements for the connection of DGs to the utility grid. Moreover, it allows implementing some enhanced functions for the remote control of inverters of DGs and ESSs, not only in terms of disconnection but also in terms of voltage regulation and power shuttering. The proposed solution is based on a new interface protection system and a dedicated secondary substation concentrator, which allows the communication between the distributed system operat…
Vides aizsardzības kluba darbība 1987-1989
2021
Maģistra darba mērķis ir raksturot Vides Aizsardzības kluba laika periodā no 1987.–1989. gadam un izvērtēt organizācijas nozīmi Latvijas atmodas procesos. Aplūkoto laika periodu raksturo plašas politiskās izmaņas PSRS, kuru rezultāta sākas plašāka sabiedrības iesaiste politiskajos procesos. Pētījumā tiek sniegts ieskats organizācijas priekšvēsturē un izveidē, tās galvenajos darbības virzienos, problēmjautājumos, kuru risināšanā organizācija iesaistījās visplašāk, kā arī iemeslos, kādēļ 1989. gadā klubs nolēma kļūt par apolitisku organizāciju. Maģistra darbā izmantoti Latvijas valsts arhīvā un Zaļās Atmodas muzejā pieejamie materiāli par VAK darbību, tostarp organizācijas dibināšanas materiā…
Multitemporal mapping of peri-urban carbon stocks and soil sealing from satellite data.
2017
Abstract Peri-urbanisation is the expansion of compact urban areas towards low-density settlements. This phenomenon directly challenges the agricultural landscape multifunctionality, including its carbon (C) storage capacity. Using satellite data, we mapped peri-urban C stocks in soil and built-up surfaces over three areas from 1993 to 2014 in the Emilia-Romagna region, Italy: a thinly populated area around Piacenza, an intermediate-density area covering the Reggio Emilia-Modena conurbation and a densely anthropized area developing along the coast of Rimini. Satellite-derived maps enabled the quantitative analysis of spatial and temporal features of urban growth and soil sealing, expressed …
A review of soil carbon dynamics resulting from agricultural practices
2019
Abstract Literature related to the carbon cycle and climate contains contradictory results with regard to whether agricultural practices increase or mitigate emission of greenhouse gases (GHGs). One opinion is that anthropogenic activities have distinct carbon footprints – measured as total emissions of GHGs resulting from an activity, in this case, “agricultural operations”. In contrast, it is argued that agriculture potentially serves to mitigate GHGs emissions when the best management practices are implemented. We review the literature on agricultural carbon footprints in the context of agricultural practices including soil, water and nutrient management. It has been reported that the ma…
Environmentally Friendly Fuel Usage: Economic Margin of Feasibility
2019
Abstract In the world there are two main problems concerning energy and ecology. Despite the crude oil price fluctuation, it has tended to increase. Moreover fossil fuel burning emits hazard compounds, including greenhouse gas. To solve them alternative fuels for vehicle have to be used. In due to properties, their usage impacts on the engine efficiency. The alternative fuel usage needs additional investment costs on the vehicle engines adaptation and fuel supply infrastructure. So, decisions must be based on mathematical apparatus. Three submodels were used in the suggested mathematical model: energy and economic indicator for fuels; energy and economic indicator for vehicles; criteria for…
Evaluation of the current status of operating and closed landfills in Russia, Finland and Ireland with regard to water pollution and methane emission
2003
The annual production of municipal solid wastes (MSW) in Russia, Finland and Ireland in the late 1990s accounts for 37.5, 2.5 and 2.05 mln. tonnes or 252, 488 and 566 kg per capita, respectively. 96.5, 64 and 91% of these wastes (for Russia, Finland and Ireland, correspondingly) are currently disposed of via landfilling. However, nowadays, MSW management in these countries is undergoing drastic changes (source separation, closure of old landfills, reduction of the number of landfills etc.) forced by recent legislation set by the European Union and Russian authorities. This paper evaluates the current status of MSW landfills, as well as information on current leachate and methane emissions i…
Polychlorinated biphenyls and some pesticides in perch (Perca Fluviatilis) from inland waters of Latvia
1999
Polychlorinated biphenyls (PCBs), DDT - related substances, hexachlorocyclohexane (HCH) isomers and hexachlorobenzene (HCB) were analysed in perch (Perca fluviatilis) from Latvian lakes and rivers. DDE is present in the highest concentrations in all samples; 62–170 ng/g lipid weight in perch from rural areas and 460 ng/g in perch from the Riga area. Individual dominating PCB congeners were in the range 16–45 ng/g and 200–210 ng/g, respectively. The degree of contamination of rural areas in Latvia of these organohalogen substances is in the same range as in background areas in Sweden. Riga, the major urban area in Latvia, is shown to be more polluted with PCBs than other areas in Latvia.
Agricultural land abandonment in Mediterranean environment provides ecosystem services via soil carbon sequestration
2016
Abandonment of agricultural land leads to several consequences for ecosystem functions. Agricultural abandonment may be a significant and low cost strategy for carbon sequestration and mitigation of anthropogenic CO2 emissions due to the vegetation recovery and increase in soil organic matter. The aim of this study was to: (i) estimate the influence of different Soil Regions (areas characterized by a typical climate and parent material association) and Bioclimates (zones with homogeneous climatic regions and thermotype indices) on soil organic carbon (SOC) dynamics after agricultural land abandonment; and (ii) to analyse the efficiency of the agri-environment policy (agri-environment measur…
The use of mosses in biomonitoring of selected areas in Poland and Spitsbergen in the years from 1975 to 2014
2015
We have compared historical changes in concentrations of the heavy metals Mn, Ni, Cu, Zn, Cd and Pb accumulated in samples from the Polish woodlands of Beskidy and Karkonosze (S, SE Poland) and the north-east regions of the country, versus the relatively little polluted areas of Spitsbergen of the Svalbard Archipelago. We have combined the results from literature with new results from 2014. The regions of Beskidy and Karkonosze were the most exposed to heavy metals deposition. However, from 1975 to 2014 there was a considerable decrease of concentrations of Cu, Zn, Cd and Pb at all Polish sites, clearly signifying improvement of environmental quality. For example, the average Cd concentrati…
Willingness of Student to Favour the Protection of Endangered Species in a Trade-off Conflict in Finland
1994
Abstract This paper explores the willingness of Finnish students to favour protection of endangered species in a hypothetical trade-off conflict, where conservation would cause an increase in the household energy cost. The most striking result was the very distinct preference of species which the students felt worth protecting. The students favoured species which are well known, taxonomically close to man and actually endangered. Major differences occurred among students due to sex, educational institute, nature-related activity groups, as well as knowledge of nature and conservation issues.