Wyniki wyszukiwania - Biblioteka Nauki

1

Zmienność parametrów termicznych w Arktyce Norweskiej w okresie 1951-1990

100%

Przybylak R.

Problemy Klimatologii Polarnej

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1999

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tom nr 9

23--36

EN

In the paper, changes in mea n annual intraseasonal (within season) and interannual (between years) temperature variability have been analysed over the Norwegian Arctic for the period 1951 to 1990. The daily maximum (TMAX) r mean (TSR), minimum (TMIN) temperatures and the diurnal temperature range (AMP) for the Jan Mayen and Hopen stations were examined. The temperature variability parameters and the method of computations was the same as in Plummer (1996), except the computation method of the long-term daily mean values, which here were obtained by averaging daily data from the period 1951-1990. Plummer have received these series by performing a Fourier analysis of their monthly mea n and interpolating from their respective average annual cycles. In the Norwegian Arctic, similarly as for Australia (Plummer 1996), trends in intraseasonal temperature variability were mixed and in all cases not statistically significant (Figs 1-8). These results are in good agreement with the observed lack of warming in the studied area over the period 1951-1990 (Przybylak 1996, 1997). Most sensitive to high-frequency temperature variability, of the four thermic parameters, is TMAX. Plummer (1996) also found similar results for Australia. The range of changes in intraseasonal variability and their values decreases when the time-scale of averaging intervals increases. Small, not statistically significant, increases in interannual variability for all thermic parameters were observed in the studied area (Fig. g). The greatest interannual variability in both analysed stations shows TMIN and the lowest AMP. In Australia Plummer found TMAX as the most sensitive to this kind of variability.

2

Influence of traffic flow variability of heavy vehicles and temperature on pavement fatigue life

84%

Spławińska M. , Zieliński P. , Burnos P.

Roads and Bridges - Drogi i Mosty

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2015

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tom Vol. 14, no. 2

117--132

PL

W pracy przedstawiono wpływ zmienności temperatury i natężeń ruchu pojazdów ciężkich na trwałość zmęczeniową podatnych nawierzchni drogowych (nawierzchnie z podbudową z kruszywa niezwiązanego oraz z betonu asfaltowego. Podziału terytorium Polski na grupy jednorodne ruchowo i temperaturowo dokonano przy łącznym wykorzystaniu metod ilościowych (analiza skupień oraz jakościowych (przynależność geograficzno-funkcjonalna. Podstawą podziału był kształt profili zmienności temperatury oraz natężeń ruchu w kolejnych miesiącach w roku i w następujących po sobie sezonach. Po określeniu jednorodnych grup wyznaczono dla nich reprezentatywne profile zmienności natężeń ruchu oraz temperatury, które wykorzystano do obliczenia trwałości zmęczeniowej konstrukcji nawierzchni. Trwałość zmęczeniową wyznaczono wykorzystując kryterium zmęczeniowe warstw asfaltowych według Instytutu Asfaltowego. Obliczenia stanu naprężeń i odkształceń w nawierzchni przeprowadzono z wykorzystaniem programu BISAR. Uzyskane wyniki pozwoliły na porównanie oraz wskazanie różnic w otrzymanych trwałościach nawierzchni w zależności od przyjętych wartości temperatury ekwiwalentnej.

EN

The paper presents the effect of temperature variability and traffic flow variability on fatigue life of flexible road pavements (pavements with the subgrade made of unbound aggregates and asphalt concrete'. The division of the territory of Poland for the homogeneous groups in terms of movement and temperature was made at the use of quantitative methods (cluster analysis' and qualitative methods (geographical and functional affiliation'. The basis for the division was the shape of the profiles of temperature and traffic flow variability in subsequent months of the year and in successive seasons. After determining homogeneous groups, representative profiles of traffic flows and temperature variability were established, which were used to calculate the fatigue life of pavement structure. Fatigue life was determined using the criterion of fatigue of asphalt layers according to the Asphalt Institute. The calculations of stress and strain in the pavement were carried out using the program BISAR. The results have permitted comparison and identification of differences in pavement durability obtained depending on the values of equivalent temperatures.

3

Changes in electromyographic signals and skin temperature during standardised effort in volleyball players

84%

Kuniszyk-Jóźkowiak W. , Jaszczuk J. , Czaplicki A.

Acta of Bioengineering and Biomechanics

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2018

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tom Vol. 20, no. 3

115--122

EN

The state of athletes’ muscles is not constant, but it differs depending on the stage of sports training, which is associated with different degrees of muscle fatigue. There is thus a need to find a non-invasive and simple method to assess muscle fatigue. The aim of the study was to determine the relationship between muscle fatigue due to physical effort and changes in skin temperature, measured using a thermographic camera. Methods: The study involved 12 volleyball players. The participants were to maintain 70% of peak torque in the joint for as long as possible. We measured peak torque and the time of maintaining 70% of its value (tlim) as well as continuously recording skin temperature and electromyographic (EMG) signals in the region of the belly of the rectus femoris. The measurements were taken twice: before and after a series of squats. Results: The study found that tlim decreased when isometric contraction was performed after physical effort. Pre- and post-exercise skin temperature did not differ significantly, however, the increase rates of temperature and the root mean square (RMS) of the EMG signals grew significantly. In most of the players, skin temperature also correlated with the RMS, median frequency (MDF), and mean frequency (MF) of the EMG signals. Conclusions: Measuring the time of maintaining submaximal torque during isometric contraction and the slope coefficient for the increase in temperature recorded using a thermographic camera can be a simple, cost-effective, and non-invasive method of assessing fatigue and efficiency decreases in the muscles in volleyball players.

4

Wykorzystanie analizy skupień do analizy szeregów czasowych zmian temperatury w lokalach mieszkalnych w sezonie grzewczym

84%

Bylicki J. , Stańczyk J. , Kajewska-Szkudlarek J. , Łomotowski J. , Licznar P.

Instal

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2017

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tom nr 9

46--49

PL

Indywidualne wymagania mieszkańców, co do komfortu cieplnego w pomieszczeniach mieszkalnych, mają wpływ na wielkość poboru ciepła. Czynniki te nakładają się na losową zmienność temperatury powietrza zewnętrznego, co wpływa w istotny sposób na prognozowanie ilości ciepła dostarczanego do pomieszczeń mieszkalnych w okresie grzewczym. W artykule przedstawiono wyniki badań zmian temperatury powietrza zewnętrznego oraz temperatury wewnętrznej w mieszkaniach w budynku wielorodzinnym. Podjęto próbę określenia wpływu temperatury zewnętrznej na zachowania się użytkowników mieszkań celem utrzymania temperatury wewnątrz pomieszczeń. Wykazano, że analiza skupień (ang. Cluster Analysis) pozwala na wyodrębnienie charakterystycznych grup pomieszczeń, których mieszkańcy mają podobne wymagania w stosunku do temperatury wewnętrznej. Wyniki badań mogą być przydatne przy opracowaniu algorytmów sterowania pracą wewnętrznych instalacji centralnego ogrzewania.

EN

The individual residents' requirements concerning the heat comfort in the living space affect the amount of heat they use. These factors overlap with the random variation of outdoor air temperature, which significantly influences the forecasting of the amount of heat delivered to the living space during the heating season. The article presents the results of the outdoor air temperatures and indoor temperature changes in a multi-family building studies. An attempt to determine the outdoor temperature influence on the behavior of apartment residents in order to maintaining indoor temperature was made. It was shown that Cluster Analysis allows for the isolation of characteristic groups of premises whose residents have similar requirements with respect to indoor temperature. Study results may be useful for developing control algorithms for internal central heating systems.

5

Variability of shoulder girdle temperature in the initial phase of the snatch in weightlifting

84%

Kuniszyk-Jóźkowiak W. , Jaszczuk J. , Czaplicki A. , Szyszka P.

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2019

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tom Vol. 21, no. 3

143--148

EN

The identification of activation, synchronization and work of individual muscles in the subsequent stages of lifting weights is interesting for researchers and trainers. Unfortunately, the existing methods of research do not provide such possibilities. Such information could be gathered from infrared measurements as they are non-invasive and can be carried out without the direct involvement of the weightlifter. The purpose of the study was to analyse temperature changes in the shoulder girdle in the first phase of the snatch in weightlifting. Methods: The study involved 11 weightlifters who competed in two weight categories, 94 and 105 kg, during the World University Championships in 2018. The performance of the snatch was recorded using a thermographic camera in three consecutive attempts. We analysed the temperature changes in the left and right shoulder girdles in the two initial stages of the snatch. Statistical analysis of empirical data was performed using linear mixed effects models. Results: Statistically significant temperature increases were found from the moment of gripping the barbell to the moment it was pulled. These effects were different in individual weightlifters, but did not depend on the attempt or the side of the body. Conclusions: Temperature increases in the initial phase of the snatch are most likely the result of activating successive motor units in order to perform the effort needed to pull the barbell and cause it to accelerate. The results obtained confirm that thermography is an effective method of monitoring muscle activity in weightlifting, which may be useful for coaches and athletes.