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Wyświetlanie 1-6 z 6
Tytuł:
Badania zawartości rtęci w węglach przeznaczonych dla odbiorców indywidualnych
Studies of mercury content in coal intended for individual customers
Autorzy:
Klojzy-Karczmarczyk, B.
Mazurek, J.
Powiązania:
https://bibliotekanauki.pl/articles/283213.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
składy opału
węgiel kamienny
sortymenty węgla
rtęć całkowita
fuel depots
coal
coal assortments
total mercury content
Opis:
Polska jest krajem, w którym tradycyjnie od lat budynki jednorodzinne i małe obiekty usługowo-handlowe na terenach zabudowy rozproszonej (wieś, małe miasta) ogrzewane są najczęściej paliwem węglowym. Odbiorcy indywidualni zaopatrują się w węgiel głównie na składach opałowych. Składy opału sprzedają wiele gatunków (sortymentów) węgla z różnych kopalń. Węgiel sprzedawany na składach różni się od urobku wydobytego bezpośrednio z pokładu (jest produktem wzbogaconym głównie poprzez rozdrobnienie i w efekcie pozbawienie skały płonnej). W związku z tym można spodziewać się, że zawartość metali ciężkich (w tym rtęci) w próbkach węgla kamiennego pobranych ze składu jest inna niż w próbkach pobranych bezpośrednio z ociosów eksploatowanej ściany. Obecność rtęci w węglach jest zjawiskiem powszechnie znanym i udokumentowanym. Jej zawartość w próbkach węgla kamiennego pochodzących z różnych złóż światowych kształtuje się najczęściej na poziomie od 0,03 do 0,3 mg/kg, przy czym zawartość rtęci w poszczególnych pokładach jest znacznie zróżnicowana. Z kolei w dostępnej literaturze mało prezentowanych jest wyników badań zawartości rtęci w produkcie końcowym, zlokalizowanym na składach opałowych, a trafiającym w konsekwencji do odbiorcy indywidualnego. W pracy przedstawiono wyniki badań zawartości rtęci całkowitej w 25 próbach różnych sortymentów węgla kamiennego, pochodzących z ośmiu kopalń Górnośląskiego Zagłębia Węglowego. Węgle do badań zostały zakupione w ilości 25 kg z każdego sortu, na jednym z większych, autoryzowanych składów opału z terenu Małopolski, zaopatrującym głównie odbiorców indywidualnych i małe firmy. Wytypowane do badań próby węgli reprezentują zarówno grubsze sortymenty, jak również sortymenty paliwa modyfikowanego (ekogroszek, odsiewka, zmieszany miał węglowy). W opisie prób zastosowano nazewnictwo handlowe, pod jakim sprzedawany jest dany rodzaj paliwa węglowego. Z każdej dużej 25-kilogramowej próby pobrano losowo 5 próbek, które po homogenizacji poddano analizie na zawartość rtęci całkowitej. Wykonane analizy zawartości rtęci wykazały jej zróżnicowaną obecność w całym badanym materiale. Średnia zawartość rtęci w przebadanych próbkach kształtuje się na poziomie zbliżonym, choć niższym w porównaniu do danych podawanych w literaturze dla próbek pobieranych bezpośrednio ze złoża. W badanych węglach nie stwierdzono również sporadycznych wysokich zawartości punktowych rtęci, obserwowanych niekiedy w próbkach złożowych. Zawartość rtęci całkowitej oznaczona we wszystkich przebadanych próbkach węgla kamiennego zawiera się w granicach od 0,0072 do 0,0852 mg/kg, natomiast jej wartość średnia wynosi 0,0416 mg/kg (w stanie powietrzno-suchym). Brak jest większego zróżnicowania zawartości rtęci w zależności od sortymentu. Jedynie dla próbek reprezentujących różne rodzaje miału węglowego oraz w pojedynczych przypadkach dla ekogroszku i groszku można zauważyć ponad dwukrotne podwyższenie zawartości rtęci w stosunku do uzyskanej średniej. Jak wynika z przeprowadzonych badań, wzbogacanie węgla może wpływać na obniżenie zawartości szkodliwych domieszek rtęci w produkcie finalnym, sprzedawanym na składach opałowych.
Poland is a country where traditionally for many years houses and small commercial buildings in dispersed settlements (rural villages, small towns) are most commonly heated using coal. Individuals buy the coal mainly from fuel depots. These depots sell many assortments of coal from different mines. Coal sold at the depots is different from the raw material extracted directly from the seam. It is a product beneficiated mainly by fragmentation, resulting in deprivation of waste rock. Therefore, it can be expected that the content of heavy metals (including mercury) in samples taken from the coal at a depot is different than in samples taken directly from an operating face of a mining longwall. The presence of mercury in coal is a well-known and documented phenomenon. Its content in coal samples from different deposits around the world is usually at a level between 0.03 and 0.3 mg/kg, although the mercury content in particular seams varies significantly. However, existing research offers only a few studies of mercury content in the final product located at fuel depots, which is consequently utilized by individual customers. This paper presents the results of a study of the total mercury content in 25 samples of various coal assortments from eight mines of the Upper Silesian Coal Basin. The examined coal was purchased in quantities of 25 kg of each assortment at one of the largest, authorised fuel depots in the Malopolska region which supplies mainly individuals and small businesses. The coal samples selected for the study represent both thicker assortments as well as modified fuel assortments (eco-pea coal, remnant, mixed coal dust). In the description of the samples, trade names under which a particular type of coal fuel is sold were used. From each large, 25-kilogram test sample, five smaller samples were randomized and, after homogenization, analyzed for total mercury content. The completed analyses of mercury content indicated its diverse presence throughout the studied material. The average mercury content in the tested samples is at a similar level, but significantly lower than the data reported in studies of samples taken directly from the deposit. In the analysed coal, the occasional spikes in mercury content sometimes found in the deposit samples were not observed. Total mercury content determined for all the tested samples of coal ranged from 0.0072 to 0.0852 mg/kg, whereas the mean value was 0.0416 mg/kg (in the air-dry state). No bigger differences in mercury content were observed regardless of the assortment. Only in samples from various types of coal dust and in one case of eco-pea coal and pea coal was increased mercury content of more than double the obtained mean value noticed. As is clear from the conducted research, the beneficiation of coal can result in a lower content of harmful mercury impurities in the final product sold at fuel depots.
Źródło:
Polityka Energetyczna; 2013, 16, 4; 151-161
1429-6675
Pojawia się w:
Polityka Energetyczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metoda standaryzacji kosztów jednostkowych ścinki i wyrobu sortymentów
Method of standardizing of unit costs of felling and production of wood assortments
Autorzy:
Kocel, J.
Powiązania:
https://bibliotekanauki.pl/articles/978876.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
standard costs
felling and production of wood assortments
grouping method for forest districts
financial
system of the state forests
Opis:
The paper presents the standardization of felling and production of assortments costs by the method of grouping forest districts with similar natural conditions. The standard costs were compared with the incurred (actual) and planned costs, and the method of determining the standard unit costs of felling and production of assortments was assessed in terms of its use in the State Forests National Forest Holding financial system. Source materials for 2017 were obtained from the databases of the State Forests Information System for all forest districts and used to develop standard unit costs. The method of costs standardization determined 12 uniform groups of forest districts in terms of the structure of harvested timber assortments and the share of dominant tree species in the total area of forest districts. Then for each group 5% of outlying values were excluded based on mean and standard deviation. Next, average value for such truncated number of cases was calculated and defined as the standard costs. Pearson linear correlation was used to examine the relationship between actual, planned and standard unit costs. We found significant relationship between the investigated types of costs. The significant relationship was found also among weighted averages of actual, planned and standard unit costs calculated for regional directorates of the State Forests. No significant differences was observed between average unit costs not reflected in the financial practice of the State Forests. Slight differences in analysed costs constitute significant cost values on the scale of the whole company as felling and production of assortments consists of many tasks. The presented method of forest districts grouping should be used to standardize unit costs of felling and assortments production, which would be helpful in financial planning at the various levels of the management in the State Forests. Values omitted in the presented method require additional analyzes. Separate assessment is also required for the factors (justified or unreasonable) causing deviations in forest districts obtaining actual costs departing from the costs of other forest districts included in the same assortment and species group.
Źródło:
Sylwan; 2020, 164, 09; 736-746
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pozyskanie drewna w nadleśnictwach Puszczy Białowieskiej w latach 2008-2015
Harvest of timber in forest districts of the Bialowieza Forest in 2008-2015
Autorzy:
Zastocki, D.
Lachowicz, H.
Sadowski, J.
Moskalik, T.
Nietupska, M.
Powiązania:
https://bibliotekanauki.pl/articles/985925.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Puszcza Bialowieska
gospodarka lesna
nadlesnictwa
pozyskiwanie drewna
sortymenty drewna
lata 2008-2015
białowieża forest
cutting categories
assortments
nature−valuable areas
Opis:
The paper presents a multifaceted structure of timber harvest in 2008−2015 in the Białowieża, Browsk and Hajnówka forest districts located in the Białowieża Forest. The object of the research, including the Białowieża National Park being a remnant of the primeval forests, is considered one of the most valuable forest areas of natural origin in Europe. The studies were made on the basis of the data from the reports created by the State Forests Information System and forest management plans, as well as the nature conservation programs of the surveyed forest districts. In the analysed period, a total of 665,032.5 m3 of merchantable timber was harvested in the analysed area. The highest volume of merchantable timber was harvested in the Browsk Forest District – 305,934 m3 (46%), then in the Hajnówka Forest District – 219,300 m3 (33%), with the lowest volume harvested in the Białowieża Forest District 139,788 m3 (21%). Among the individual assortment groups, the medium−sized timber was the most common and its harvested volume amounted to 413,579 m3, while the harvested volume of large−sized timber amounted to 251,454 m3. The lowest harvested volume concerned the small−sized timber and amounted to 21,652 m3. In the analysed period, softwood had the largest share in timber harvest and amounted to 443,469 m3. Hardwood was obtained in the volume of 243,215 m3. According to the cutting category, the timber harvest structure was as follows: the highest volume was harvested in pre− commercial thinning 382,495 m3 (54%), that from incidental felling amounted to 251,003 m3 (38%), while the lowest volume of harvested timber was from final cutting – 53,186 m3 (8%). Forest districts located in the Białowieża Forest encounter many difficulties affecting timber harvest. The main reason for this lies in the numerous restrictions imposed on the management of areas covered by various forms of nature protection, including the exclusion of some habitats, or stands of 100 years of age and older from management, which significantly affects the yield. The lack of a determined rotation age for stands in the Białowieża Forest also has a significant impact on timber harvest.
Źródło:
Sylwan; 2018, 162, 11; 941-948
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ klęsk żywiołowych na rynek drzewny
The effect of natural disasters on the timber market
Autorzy:
Sikora, A.T.
Powiązania:
https://bibliotekanauki.pl/articles/1293666.pdf
Data publikacji:
2017
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
lesnictwo
lasy
kleski zywiolowe
skutki ekonomiczne
rynek drzewny
surowce drzewne
sortymenty drewna
odbiorcy
timber market
timber assortments
wood buyers
natural disasters
Opis:
The aim of the study was to determine the impact an increased wood supply from the Beskid forests after natural disasters on the timber economy of the Węgierska Górka Forest District and its surroundings in the years 2004–2010. The analysis was based on the wood raw material sales recorded in the database of the State Forestry Information System (SILP). Information on the buyers’ location and their main use for the raw material were obtained through the Central Statistical Office. Furthermore, wood material buyers were classified according to the Polish Classification of Activities (PCA) based on the year 2007, using only a subjective analysis designed for enterprises and other economic units in the national economy. Changes in sales of wood material to the selected buyer groups were investigated using statistical analyses of linear trends. A Pearson’s correlation analysis verified the relationships between the buyer groups and the supply of timber assortments by the Węgierska Górka Forest District. Other studies have also shown that an increased supply of raw material in the context of natural disasters affects the types of wood buyers and their location. In addition, they have shown an increase in interest towards the purchase of raw materials among buyers engaged in the wholesale trade of wood and other non-wood producers which in turn decrease the share purchased by sawmills.
Źródło:
Leśne Prace Badawcze; 2017, 78, 4
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ceny surowca drzewnego w warunkach klęsk żywiołowych w Nadleśnictwie Węgierska Górka
Timber prices after natural disasters in the Forest District of Wegierska Gorka
Autorzy:
Sikora, A.T.
Ukalska, J.
Powiązania:
https://bibliotekanauki.pl/articles/1317481.pdf
Data publikacji:
2014
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
lesnictwo
Nadlesnictwo Wegierska Gorka
kleski zywiolowe
pozyskiwanie drewna
surowce drzewne
drewno
sortymenty drewna
ceny jednostkowe
rynek drzewny
natural disasters
timber assortments
unit prices
the timber market
Opis:
The aim of the study was to determine the impact of increased timber logging after natural disasters on timber assortments, unit prices, as well as average prices of timber spruce and total timber. The net sales prices of the years 2004-2010, available from the database of the State Forests Information System (SFIS) for the Forest District of Węgierska Górka, were analysed and compared to the prices of selected forest districts within the Regional Directorate of State Forests in Cracow (RDSF). The forest districts were classified based on the volume of logged timber leading to a separation into two groups of two and six forest districts. Moreover, we tested for significance in the linear trends of relevant characteristics and determined confidence intervals. Furthermore, we calculated the rate of growth (decrease) of the unit prices. Our studies show a decrease in price of only some of the timber assortments despite a significantly increased supply. Price declines were observed for the average prices of timber spruce and total timber due to their lowered quality. The price of timber assortments was mainly determined by effects of macroeconomic factors.
Źródło:
Leśne Prace Badawcze; 2014, 75, 2; 201-212
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ceny sprzedaży drewna w użytkowaniu przedrębnym w drzewostanach sosnowych w zależności od ich wieku
Prices of timber sales in the intermediate harvest in Scots pine stands depending on their age
Autorzy:
Mandziuk, A.
Parzych, S.
Powiązania:
https://bibliotekanauki.pl/articles/979471.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Panstwowe Gospodarstwo Lesne Lasy Panstwowe
drzewostany sosnowe
wiek drzewostanu
uzytkowanie przedrebne
surowce drzewne
drewno
sortymenty drewna
ceny sprzedazy
site class index
timber price
assortments
intermediate harvest
Opis:
The research concerned the implementation of tasks in the field of harvesting timber in 2008−2012 in pure pine stands aged 10−140. Numerical data from the SILP database were used for calculating the average price of timber in the intermediate harvest. The data on the volume harvested covered late cleaning, early thinning and late thinning. The assortment structure concerned the following groups of large− (WA0, WA1, WB0, WB1, WC0, WC1 and WD), medium− (S10, S11, S2A, S2B, S3A, S3B and S4) as well as small−sized (M1 and M2) assortment groups. The data on the size and value of wood assortments sold across the country concerned the year 2011 and were used to calculate the average price of wood in age subclasses according to the site quality described with site index class. Subsequently, for each site quality class polynomial equations of the trend line was determined and average timber price for each age subclass was calculated for small−, medium− and large−sized assortments. The analysis showed that S2 is the most frequently harvested assortment in the intermediate cuts in Scots pine stands, whose share depending on the site quality class is at the level of 65.7−72.7% of total harvest. The share of small−sized assortments decreases with age in all site quality classes. The opposite tendency is seen for large−sized assortments, whose share decreases with the deterioration of the site quality. Fraction of medium−sized assortments reaches its peak at the age of ca 45 in IA site index class and the shift in the peak with age is associated with the deterioration of the site quality. The higher the site quality, the higher the prices of assortments in the intermediate harvest. This trend occurs in all age subclasses.
Źródło:
Sylwan; 2019, 163, 11; 883-891
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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