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Tytuł:
Efektywność pozyskiwania drewna harwesterem w młodszych trzebieżowych drzewostanach sosnowych w zależności od technologii pracy
Efficiency of timber harvesting using harvester in thinned young pine stands as a function of working technique
Autorzy:
Stańczykiewicz, Arkadiusz
Szewczyk, Grzegorz
Brzoza, Bartosz
Powiązania:
https://bibliotekanauki.pl/articles/18055686.pdf
Data publikacji:
2023
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
metoda drewna krótkiego z międzypolem
trzebieże wczesne
pozyskanie ręczno-maszynowe
pozyskanie maszynowe częściowo zautomatyzowane
wydajność pracy
czasochłonność pracy
CTL method with midfield
early thinning
motor-manual logging
semi-automated logging
work efficiency
worktime consumption
Opis:
In Poland, more and more timber is harvested with the use of harvesters of different types. These machines can also be used in cooperation with chainsaw operators, e.g. in stands damaged by violent winds, in the removal of windthrows, or in stands of younger age classes in the technological variant with the so-called „midfield”. The aim of the study was to characterise the working time structure and to estimate the efficiency of timber harvesting with a harvester in two technological variants. In the first variant, the felling of trees was carried out by a chainsaw operator and the processing was performed by a harvester operator. In the second variant all operations were carried out by a harvester operator. In both variants, the machine worked on the skid trails, but in the second variant, the operator descended from the skid trails a short distance into the stand. Harvesting was conducted in two pine stands that were approximately the same age and differed in site conditions. The structure of the harvester operator's work time was clearly dominated by the moving of felled trees to the skid trails in both variants. Of all the activities studied, the observed differences between their durations in both variants were insignificant only in the case of delimbing and bucking (processing). In the case of cooperation between harvester operator and chainsaw operator, a higher work efficiency was achieved than in the case of timber harvesting with a harvester alone. At the same time, significantly lower work time consumption was observed. However, when considering the efficiency of the entire technologies, thinning with two workers was 30-60% more time consuming. Significant relationships were found between the amount of merchantable timber of harvested trees and the efficiency of the harvester operator.
Źródło:
Leśne Prace Badawcze; 2023, 83; 16-24
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A simulation of thinning of microphone array in near-field broadband beamformers
Autorzy:
Wielgus, Agnieszka
Szlachetko, Bogusław
Powiązania:
https://bibliotekanauki.pl/articles/2146656.pdf
Data publikacji:
2021
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
acoustics
beamforming systems
microphone array
thinning technique
akustyka
beamforming
macierz mikrofonów
technika przerzedzania
Opis:
This paper is devoted to the problem of designing an optimal microphone matrix. We define a criterion function where the performance of our matrix should be as close as possible to the desired one based on L2 norm. In the classical approach, increasing a size of the matrix is used to improve the system performance. However, in many cases it is not a good solution. In this paper we propose a solution based on thinning technique. We work with rectangular, equispaced microphone matrix and using metaheuristic approach called simulated annealing we optimise the set of active microphones (we switch off some of the microphones from the regular matrix). For illustrations, few numerical examples are solved. Comparing to the classical approach we show that thinning microphone matrix can significantly improve system performance.
Źródło:
Vibrations in Physical Systems; 2021, 32, 2; art. no. 2021204
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of thinning of homogeneous material using active thermography and classification trees
Autorzy:
Dudzik, Sebastian
Dudek, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1848987.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active thermography
classification tree
defect detection and characterization
material thinning detection
Opis:
Active thermography is an efficient tool for defect detection and characterization as it does not change the properties of tested materials. The detection and characterization process involves heating a sample and then analysing the thermal response. In this paper, a long heating pulse was used on samples with a low thermal diffusivity and artificially created holes of various depths. As a result of the experiments, heating and cooling curves were obtained. These curves, which describe local characteristics of the material, are recognized using a classification tree and divided into categories depending on the material thickness (hole depths). Two advantages of the proposed use of classification trees are: an in-built mechanism for feature selection and a strong reduction in the dimensions of the pattern. Based on the experimental study, it can be concluded that classification trees are a useful tool for the thinning detection of homogeneous material.
Źródło:
Metrology and Measurement Systems; 2021, 28, 1; 89-105
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porównanie efektywności mechanicznego przerzedzania kwiatów do chemicznego i ręcznego przerzedzania zawiązków owocowych jabłoni odmian ‘Gala Must’ i ‘Red Jonaprince’
Comparison of the effectiveness of mechanical thinning of flowers to chemical and manual thinning of fruitlets of apple trees ‘Gala Must’ and ‘Red Jonaprince’
Autorzy:
Buler, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2118897.pdf
Data publikacji:
2021
Wydawca:
Instytut Ogrodnictwa
Tematy:
apple tree
thinning
yielding
fruit quality
Opis:
Eight-year-old abundantly blooming apple trees ‘Gala Must’ and ‘Red Jonaprince’ grafted on a dwarf rootstock M.9, spaced 3.5 × 1.5 m and 3.5 × 1.8 m, were subjected to bloom and fruit thinning. This included 7 types of treatments: 1. (M) mechanical flower thinning in the full bloom stage with the German produced BAUM appliance; 2. (C) chemical thinning of fruitlets with cytokinins (Globaryll product); 3. (R) hand fruit thinning in June; 4. (M+C) mechanical thinning of flowersin full bloom, followed by chemical thinning of fruitlets in June as in point 3; 5. (M+R) mechanical thinning of flowers in full bloom stage, followed by hand fruit thinning in June; 6. (C+R) chemical thinning of fruitlets, followed by hand fruit thinning in June; 7. (K) control – no thinning. All thinning treatments decreased yield but increased the size of the fruit, the mean fruit weight, and the growth of the shoots. Among the treatments applied to ‘Gala Must’ trees, the best results were obtained with the M and M+R treatments. Most of the fruit had a favorable marketing size, in the range of 7.5–8.5 cm. The M+C and C+R treatments resulted in too many overgrown apples, which are prone to physiological disorders during storage. Among the treatments applied to ‘Red Jonaprince’, the best results were obtained with M and M+R. The other treatments resulted in an excessively large drop in yield and a very high share of overgrown fruit over 9.0 cm in diameter, unacceptable on the market. The thinning treatments increased the solubility of the solids in the fruit of both cultivars with no clear effect on their firmness.
Źródło:
Zeszyty Naukowe Instytutu Ogrodnictwa; 2021, 29; 1-14
2300-5882
2391-8969
Pojawia się w:
Zeszyty Naukowe Instytutu Ogrodnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variation Between Voivodships in Terms of Forest Area and Silviculture Activities in Polish Forests in 2015-2019
Autorzy:
Grużewska, Agata
Rymuza, Katarzyna
Niewęgłowski, Marek
Powiązania:
https://bibliotekanauki.pl/articles/2069934.pdf
Data publikacji:
2021
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
forest area
forest regeneration
afforestation
thinning
voivodship
Opis:
The objective of the study reported here was to compare voivodships in terms of forest area, forest regeneration area, afforested area, thinned forest area and natural forest regeneration area Main Statistical Office data for Polish voivodships was analysed. It included forest area, natural forest regeneration and silviculture activities (forest regeneration, afforestations and thinning) in all forests, state-owned forests and privately-owned forests. Voivodships were compared using the arithmetic mean, the indicator of structure, the average rate of change, principal component analysis and cluster analysis. Principal Component Analysis, revealed that state-owned forest area, forest regeneration in state forests, total forest regeneration, and thinning in state-owned forests had the greatest share in the multivariate variation among voivodships analysed in terms of forestry. Cluster analysis yielded two groups of voivodships. The voivodships in the first group had a higher average total forest area, area of state-owned forests, total area of forest regeneration and forest regeneration in state-owned forests, area of natural forest regeneration and thinning in state-owned forests. On average, forests of voivodships which formed group 2 included less privately-owned forests in which fewer forest regeneration and afforestation activities had been conducted. Opolskie and Śląskie Voivodships as well as Łódzkie and Świętokrzyskie Voivodships were the most similar in terms of all the analysed characteristics.
Źródło:
Rocznik Ochrona Środowiska; 2021, 23; 524--538
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ mechanicznego przerzedzania kwiatów urządzeniem BAUM na plonowanie i jakość owoców czereśni odmiany ‘Summit’
Effect of mechanical thinning of flowers by BAUM device on yielding and fruit quality of sweet cherry ‘Summit’
Autorzy:
Filipczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/2118941.pdf
Data publikacji:
2021
Wydawca:
Instytut Ogrodnictwa
Tematy:
sweet cherry
mechanical flower thinning
BAUM
Opis:
Thinning of flowers or fruitlets is currently one of the most important agrotechnical treatments in the cultivation of some fruit trees. This paper presents the results of the research on the effect of mechanical thinning of flowers on the yield and fruit quality of ‘Summit’sweet cherries. The experiment was carried out in 2018 at the Pomological Orchard of the National Institute of Horticultural Research in Skierniewice. Mechanical thinning of flowers was carried out with a BAUM machine at two rotor speeds: 300 rpm and 420 rpm. Compared with the control, the obtained results showed that mechanical flower thinning at the rotor speed of 420 rpm resulted in the greatest reduction in the fruit yield (21,5%) and the greatest increase in the weight of a single fruit (26,9%).
Źródło:
Zeszyty Naukowe Instytutu Ogrodnictwa; 2021, 29
2300-5882
2391-8969
Pojawia się w:
Zeszyty Naukowe Instytutu Ogrodnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extraction of Ziziphus lotus fruit syrups: effect of enzymatic extraction and temperature on their rheological and chemical properties
Autorzy:
Letaief, T.
Mejri, J.
Ressureicao, S.
Abderrabba, M.
Costa, R.
Powiązania:
https://bibliotekanauki.pl/articles/2083051.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
Ziziphus lotus L.
syrup
shear-thinning
rheology
enzymatic extraction
Opis:
Fruit syrups are attracting increasing interest in the food industry. Ziziphus lotus fruit syrups were elaborated through the traditional and enzymatic methods with 30, 50 and 70° Brix. A chemical analysis revealed that Ziziphus lotus fruit powder and syrups present a potential source of energy through their relatively higher content of carbohydrates. Rheological oscillatory tests showed that syrups of 30°Brix demonstrate a viscous type of behaviour, the 70°Brix syrups possess an elastic behaviour, while the 50°Brix syrups present a mixed behaviour over the temperature range of 20 to 80°C. These syrups did not demonstrate any thixotropy or time dependence of viscosity. The complex viscosity was described successfully with a mathematical model that incorporates both independent variables, with an Arrhenius-type dependence on temperature, with an activation energy of 21.94 kJ mol-1 for the whole Brix range. The flow behaviour evaluation of the 30 and 50°Brix showed that these are shear-thinning fluids, tending to Newtonian fluids at higher temperatures. The dynamic viscosity was well described by the power law and the dependence of its parameters on temperature was adequately described by a Turian approach. The syrups of Ziziphus lotus fruit demonstrated a potential for further beneficial research with a view to obtaining a commercial food product.
Źródło:
International Agrophysics; 2021, 35, 1; 31-40
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rozmiar uszkodzeń drzew pozostających podczas nasiębiernej zrywki w drzewostanie sosnowym przy wykorzystaniu posztucznej metody szacowania
Size of the damage to the trees remaining during the digging skidding in Scots pine stand using the original method of estimation
Autorzy:
Wójcik, K.
Powiązania:
https://bibliotekanauki.pl/articles/978984.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
drzewostany sosnowe
zrywka drewna
zrywka nasiebierna
forwardery
uszkodzenia drzew
leśnictwo
oddziaływanie na las
metody szacowania szkód
damaged trees
frequency of injuries
selective thinning
skidding
forwarder
Opis:
The purpose of the research was to present problems related to the damage to the stand resulting from the scraping works performed on its surface, mainly with the use of forwarder skidding. The research was conducted in thinned Scots pine stands in the IV and V age class in the Wipsowo Forest District (northern Poland). In the selected stands we carried out the inventory of the stand layers. Based on the obtained data, the level of damage to trees after thinning operations was calculated. Damage resulting from the skidding with forwarder in the individual manipulation plots was at a level of 18.2−18.7% in the method used by the Wipsowo Forest District, while in the method proposed by the author damage level equaled 3.9−9.8%. It was found out that the highest number of damage occurred in the belt up to 5 m from the skidding trail, especially at the width of the trails below 4 m. The damage is most affected by the stand density – the higher it is, the more trees are damaged.
Źródło:
Sylwan; 2020, 164, 03; 216-225
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of chemical thinning with Armothin® on fruit set, yield and quality of Japanese plum (Prunus salicina Lindl.) cv. ‘Fortune’
Autorzy:
Bennewitz von, E.
Cabalín, A.
Lošák, T.
Powiązania:
https://bibliotekanauki.pl/articles/12686808.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
plant cultivation
Japanese plum
Prunus salicina
Fortune cultivar
chemical thinning
Armothin preparation
Opis:
The effects of the application of the chemical thinner Armothin® on fruit set, yield and quality of Japanese plum (Prunus salicina Lindl.) cv. ‘Fortune’ were studied during two seasons in Central Chile (34.56°S, 71.5°W). Trees were sprayed with Armothin® at 0.5%, 1% and 2% concentrations. All thinning treatments reduced the fruit set and fruitlet number (fruitlets/50 cm of branch). Armothin® at 2% conc. was the most aggressive treatment, drastically reducing the fruit set from 85.9% and 82.9% of the control and crop load to unprofitable levels during both seasons. Chemical thinning treatments at the two lowest concentrations (0.5 and 1%) did not significantly alter the crop load compared with the unsprayed control during both study seasons. Thinning costs were reduced (Armothin® 0.5%, 25.0% and 21.5% of the control treatment and Armothin® 1%, 24.6% and 24.1% of the control, during the first and second season, respectively). In general, chemical thinning increased the fruit size and total soluble solids content (TSS). Taking into account the effects on thinning, crop load, fruit quality and thinning costs, Armothin® 1% and Armothin® 0.5% are the most advantageous treatments in the case of this study.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2019, 18, 3; 211-217
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimisation of thinning of apple fruitlets cv. 'Braeburn Mariri Red'
Autorzy:
Szot, I.
Lipa, T.
Powiązania:
https://bibliotekanauki.pl/articles/13925588.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
apple tree
Braeburn Mariri Red cultivar
thinning
chemical thinning
fruitlet thinning
fruit size
benzyladenine
cytokinin
metamitron
thinning agent
Źródło:
Acta Agrophysica; 2019, 26, 3; 65-76
1234-4125
Pojawia się w:
Acta Agrophysica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ ogłowienia i przerzedzenia na wzrost grabu (Carpinus betulus L.) w młodniku dębowym (Quercus petraea (Matt.) Liebl.)
Influence of decapitating and thinning on growth of hornbeam (Carpinus betulus L.) in the oak (Quercus petraea (Matt.) Liebl.) thicket
Autorzy:
Andrzejczyk, T.
Brzeziecki, B.
Szeligowski, H.
Powiązania:
https://bibliotekanauki.pl/articles/979514.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
hodowla lasu
drzewostany mieszane
drzewostany grabowo-debowe
mlodniki
grab pospolity
Carpinus betulus
zabiegi pielegnacyjne
przerzedzanie
oglawianie
wzrost roslin
przyrost wysokosci
przyrost piersnicy
interspecific competition
pre−commercial thinning
decapitating
mixed stand
Opis:
The aim of this study was to quantify 4−year growth and increment of 11− to 15−year−old, artificially regenerated hornbeam (Carpinus betulus L.) playing the role of the tending (nursery) species in the oak stand of the same age, after the silvicultural treatments aimed at reducing its competition against the oak. The study included three types of experimental treatments: decapitating of all hornbeam trees (OG), schematic reduction of hornbeam density (R50, removal of every second hornbeam in a row) and control (K, without treatment). The trial stand is located in Rogów (51.827023° N, 19.922315° E) and was established in 2004 on a moderately fertile site. The experiment was carried out in the spring 2013 (9 years after planting). Height and breast height diameter (dbh) of trees were measured every two years. During the study period, the height increment of decapitated trees was significantly larger than in R50 and K variants, while the dbh increment of trees in R50 variant was significantly larger than in K and OG variants. The height increment of hornbeam in R50 and OG variant and the dbh increment in R50 variant were positively correlated with height and diameter of trees before the treatment, while the dbh increment after decapitating was negatively correlated with tree dimensions before treatment. The decapitating treatment reduced the competitive ability of hornbeam more effectively than the schematic thinning removing 50% of hornbeam trees. After 4 years in the first case, oaks were on average 1 m higher than hornbeams, and in the second case, there was an opposite situation. In order to improve the effectiveness of the thinning treatment, a selective cutting should be performed (removal of the largest hornbeams), and in order to slow down the regeneration of hornbeams after decapitating, the treatment should be carried out during the top of the growing season.
Źródło:
Sylwan; 2019, 163, 03; 179-187
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ sposobu zrywki i doświadczenia wykonawcy na wielkość uszkodzeń drzew na powierzchniach trzebieżowych Nadleśnictwa Chojnów
Influence of skidding method and the contractors experience on the size of tree damage on the thinning areas in the Chojnow Forest District
Autorzy:
Maciak, A.
Popczyński, B.
Powiązania:
https://bibliotekanauki.pl/articles/980293.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewostany potrzebiezowe
pozyskiwanie drewna
zrywka drewna
zrywka nasiebierna
zrywka nasiebierna laczona z wleczona
uszkodzenia drzew
operatorzy maszyn lesnych
doswiadczenie zawodowe
Nadlesnictwo Chojnow
thinning
skidding
forwarder
tractor ground skidding
damage to trees
Opis:
Skidding includes timber transport from the place of its harvest to the place of its storage, loading or pre−treatment. This process in the thinned stands can result in serious damage to the remaining trees. The purpose of the described research was to characterize and compare the size and location of damage in the thinned stands after forwarder skidding with the damages resulting from the combined forwarder and tractor ground skidding. These tests also aimed at determining whether the contractor’s experience affects the level of damage. The research was carried out on four study plots located in the Chojnów Forest District (C Poland). Although the works on each plot were performed by different contractor, they had equipment of comparable technical and overall parameters.The height of the damage, the distance of the damaged tree from the skidding trail and the size of the damage were measured. Damage was classified according to the degree of the tissue damage. The most serious damage occurs at a distance of up to 1 m from the skidding trail and at a height of up to 1 m. The most severe damage was over 1/8 of the trunk perimeter. No significant dependence of the size and location of damages on the skidding method was found.The highest fraction of the damaged trees was recorded on the area in the Młochów Forest Range (5.17%) where only the forwarder skidding took place. In the Sierzechów Forest Range (the same method of skidding, but almost twice as dense stand), there was significantly less damage (0.62%). In this case, the share of the damaged trees was the smallest, despite the highest number of trees. The reason for this may be the impact of the human factor on the amount of damage as the most experienced contractor worked on that study plot.
Źródło:
Sylwan; 2019, 163, 01; 25-34
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of thinning on Pinus pinea L. development and physico-chemical soil characteristics in northwestern Tunisia: modeling of radial growth under thinning intensity
Autorzy:
Jaouadi, W.
Mechergui, K.
Riahi, M.A.
Khouja, M.L.
Powiązania:
https://bibliotekanauki.pl/articles/2077939.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Pinion pine
silviculture
thinning intensity
stem volume
radial growth
cones production
Opis:
In this study, the potential beneficial impacts that the thinnings intensity on stand behavior and soil properties are also studied. This study was designed to test the hypothesis that thinning to various stand densities at young age enhance productivity of wood, cones and the physicochemical characteristics of the soil in Pinus pinea stands. We based our study on four thinning intensity (30, 40, 50 and 65%) in comparison with the control plot. The study was supplemented by a haracterization of radial growth of trees under the four thinning intensity. It was based on a complete randomized experimental field installed in 1994 in Tabarka forest, in Tunisia. For the radial growth analysis, three cores were taken from 125 trees at a rate of one tree per plot.The study showed that thinning has a significant effect on all dendrometric parameters. They revealed that a thinning intensity of 65% produces the best wood production (180.710 m3/ha), in annual growth in volume (4.634 m3/ha/year) and cone production (1211 cones/ha) compared to other thinning and control plot. Associated vegetation was also influenced by thinning intensities. The physicochemical characteristics of the soil were improved by thinning compared with the control. Signif- icant radial growth thinning was recorde especially in a thinning of 65% intensity (increases of 3.5 to 6.1 mm/year) compared to the control (1.1 to 2 mm/year). A strong relationship between radial growth and age was recorded at Thinning 4 (R2 = 0.923). These results can be used as an initial basis to refine silvicul- ture of pinion pine in order to improve stand productivity in Tunisia in wood and especially in cones given their importance on the world market.
Źródło:
Dendrobiology; 2018, 80; 70-80
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nondestructive investigation of wall thinning in ferromagnetic material by Magnetic adaptive testing: influence of yoke size
Nieniszczące badanie przewężenia materiałów ferromagnetycznych za pomocą adaptacyjnych testów magnetycznych: wpływ rozmiaru jarzma
Autorzy:
Vértesy, G.
Powiązania:
https://bibliotekanauki.pl/articles/107904.pdf
Data publikacji:
2018
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
electromagnetic nondestructive testing
wall thinning
magnetic hysteresis measurements
magnetic adaptive testing
magnetic field simulation
elektromagnetyczne badania nieniszczące
przewężenie materiału
pomiary histerezy magnetycznej
magnetyczne testy adaptacyjne
symulacja pola magnetycznego
Opis:
Magnetic adaptive testing is a powerful way of nondestructive evaluation. Minor magnetic hysteresis loops are systematically measured and evaluated. In the present work this technique was applied for detection of local thinning of ferromagnetic plates. The same plate with a given artificial slot was tested by different size magnetizing yokes. A definite maximum of magnetic descriptors was found, as a function of yoke size, which made possible the optimization of the yoke size for a given size of defect. The character of the maximum also revealed that the measurement is not sensitive for the geometrical parameters: the same yoke is suitable for detection of defects in a wide range. It was proved by simulation that the change of the magnetic flux density in the yoke − due to local thinning − was responsible for the observed effect. Good correlation was found between simulation and experimental data. The result of this work will help to find the optimal parameters of the experimental arrangement.
Magnetyczne testy adaptacyjne są skutecznym sposobem oceny nieniszczącej. W ich trakcie mniejszościowe pętle histerezy magnetycznej są systematycznie mierzone i oceniane. W niniejszej pracy zastosowano tę technikę do wykrywania miejscowego przewężenia płytek ferromagnetycznych. Ta sama płyta ze sztucznymi defektami została zbadana przy wykorzystaniu jarzma magnetyzującego o różnych rozmiarach. Określono maksymalną liczbę deskryptorów magnetycznych, zależnych od wielkości jarzma, co umożliwiło optymalizację rozmiaru jarzma dla danej wielkości defektu. Uzyskana charakterystyka ujawniła również brak wrażliwości wyników pomiaru na parametry geometryczne: to samo jarzmo nadaje się do wykrywania defektów w szerokim zakresie. Udowodniono, że za obserwowany efekt odpowiedzialna była zmiana gęstości strumienia magnetycznego w jarzmie - będąca wynikiem lokalnego przerzedzania. Stwierdzono dobrą korelację między symulacją a danymi eksperymentalnymi. Uzyskane wyniki umożliwią wyznaczenie optymalnych parametrów układu pomiarowego.
Źródło:
Badania Nieniszczące i Diagnostyka; 2018, 2; 45-49
2451-4462
2543-7755
Pojawia się w:
Badania Nieniszczące i Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Above- and below-ground tree parameters and their development after modelling of thinning in young elm stands
Autorzy:
Šrámek, Martin
Hurt, Václav
Čermák, Jan
Powiązania:
https://bibliotekanauki.pl/articles/956995.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
elm
leaf area
absorptive root area
biomass
thinning
Opis:
During the last century almost two-thirds of all elms were lost due to the Dutch elm disease. Therefore, elms are an endangered species with a lasting lack of knowledge about ecosystem functions of elms in forest stands. The study describes several above- and below-ground tree parameters and their changes after simulation of thinning in one young forest stand with dominant Ulmus laevis Pall. in the Czech Republic. The distribution of the leaves was measured using the ‘cloud’ technique. The absorptive root area was measured with the aid of the modified earth impedance method to evaluate below-ground tree parameters. Using allometric equations, it was possible to calculate certain tree parameters of individual trees as well as the entire forest stand. The modelling of four thinning intensities (low, medium, high and very high) helped to establish the changes of these tree parameters after treatment. The leaf area index of the stand was 5.6, the absorptive root area index was 1.7 and the total biomass of foliage was 8.5 Mg ha–1 prior to the treatment. The absorptive root area amounted to 30% of the foliage area. The exponential models were developed to predict the above- and below-ground tree parameters. Under the different thinning intensities, the following were found: a negative correlation with the number of trees for the leaf area index, the foliage biomass and the absorptive root area index. This knowledge is important in the process of maintaining the presence of endangered elms in forest stands and in ecosystem services (e.g. carbon storage) throughout Europe.
Źródło:
Dendrobiology; 2017, 77; 77-90
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
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