scholarly journals Method of Air Temperature Forecast in Mechanized Longwall Workings in the Conditions of Vietnamese Mines

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Tien Quan TRUONG ◽  
Rafał ŁUCZAK ◽  
Piotr ŻYCZKOWSKI ◽  
Marek BOROWSKI

In the most recent years, the Vietnam National Coal - Mineral Industries Holding CorporationLimited (VINACOMIN) has been dynamically developing mechanization technologies in undergroundcoal mines. The climatic conditions of Vietnam, as well as increasing the depth of the coal seams and theproduction capacity, contribute to an air temperature increasing in mining excavations. The articlepresents statistical equations enabling air temperature forecasting at the outlet of mechanized longwallworkings. The results of numerical calculations, obtained from the solutions of the adopted mathematicaldescriptions, were compared with the measurement results and the statistical significance of the obtaineddeviations was determined. The performed analysis allowed to assess the practical usefulness of theadopted model for the air temperature forecasting in the workings of mechanized underground mines inVietnam. The presented method can be used as a tool for mining services in the fight against the climatethreat in underground excavations.

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 319
Author(s):  
Cristian Pérez-Granados ◽  
Karl-L. Schuchmann

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.


2021 ◽  
Vol 185 ◽  
pp. 106158
Author(s):  
Maryam Bayatvarkeshi ◽  
Suraj Kumar Bhagat ◽  
Kourosh Mohammadi ◽  
Ozgur Kisi ◽  
M. Farahani ◽  
...  

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 68
Author(s):  
Arkadiusz M. Tomczyk ◽  
Ewa Bednorz ◽  
Katarzyna Szyga-Pluta

The primary objective of the paper was to characterize the climatic conditions in the winter season in Poland in the years 1966/67–2019/20. The study was based on daily values of minimum (Tmin) and maximum air temperature (Tmax), and daily values of snow cover depth. The study showed an increase in both Tmin and Tmax in winter. The most intensive changes were recorded in north-eastern and northern regions. The coldest winters were recorded in the first half of the analyzed multiannual period, exceptionally cold being winters 1969/70 and 1984/85. The warmest winters occurred in the second half of the analyzed period and among seasons with the highest mean Tmax, particularly winters 2019/20 and 1989/90 stood out. In the study period, a decrease in snow cover depth statistically significant in the majority of stations in Poland was determined, as well as its variability both within the winter season and multiannual.


Author(s):  
Joachim Wagner

SummaryThis paper contributes to the literature on the use of anonymized firm level data by reporting results from a replication study. To test for the practical usefulness of anonymized data I selected two of my published papers based on different cross sections of firm data. The data used there were anonymized by micro aggregation. I replicated the analyses reported in the papers with the anonymized data, and then compared the results to those produced with the original data. Frequently, the reported levels of statistical significance differ. Furthermore, statistically significant coefficients sometimes differ by order of magnitude. Therefore, at least for the moderate sample sizes used here micro-aggregated firm data should not be considered as a tool for empirical research.


2020 ◽  
Vol 5 (3) ◽  
pp. 33-48
Author(s):  
Roman M. Radchenko1 ◽  
◽  
Dariusz Mikielewicz2 ◽  
Mykola I. Radchenko1 ◽  
Victoria S. Kornienko1 ◽  
...  

The efficiency of cooling the air at the inlet of marine slow speed diesel engine turbocharger by ejector chiller utilizing the heat of exhaust gases and scavenge air were analyzed. The values of air temperature drop at the inlet of engine turbocharger and corresponding decrease in fuel consumption of the engine at varying climatic conditions on the route line Odesa-Yokogama- Odesa were evaluated.


2021 ◽  
pp. 29-39
Author(s):  
A. A. Poliukhov ◽  
◽  
D. V. Blinov ◽  
◽  

Aerosol effects on the forecast of surface temperature, as well as temperature at the levels of 850 and 500 hPa over Europe and the European part of Russia are studied using various aerosol climatologies: Tanre, Tegen, and MACv2. The numerical experiments with the COSMO-Ru model are performed for the central months of the seasons (January, April, July, and October) in 2017. It is found that a change in the simulated surface air temperature over land can reach 1C when using Tegen and MACv2 data as compared to Tanre. At 850 and 500 hPa levels, the changes do not exceed 0.4C. At the same time, it is shown that a decrease in the root-mean-square error of 2-m air temperature forecast at individual stations reaches 0.5C when using Tegen and MACv2 data and 1C for clear-sky conditions in Moscow.


Author(s):  
V. V. Hrynchak

The decision about writing this article was made after familiarization with the "Brief Climatic Essay of Dnepropetrovsk City (prepared based on observations of 1886 – 1937)" written by the Head of the Dnipropetrovsk Weather Department of the Hydrometeorological Service A. N. Mikhailov. The guide has a very interesting fate: in 1943 it was taken by the Nazis from Dnipropetrovsk and in 1948 it returned from Berlin back to the Ukrainian Hydrometeorological and Environmental Directorate of the USSR, as evidenced by a respective entry on the Essay's second page. Having these invaluable materials and data of long-term weather observations in Dnipro city we decided to analyze climate changes in Dnipropetrovsk region. The article presents two 50-year periods, 1886-1937 and 1961-2015, as examples. Series of observations have a uniform and representative character because they were conducted using the same methodology and results processing. We compared two main characteristics of climate: air temperature and precipitation. The article describes changes of average annual temperature values and absolute temperature values. It specifies the shift of seasons' dates and change of seasons' duration. We studied the changes of annual precipitation and peculiarities of their seasonable distribution. Apart from that peculiarities of monthly rainfall fluctuations and their heterogeneity were specified. Since Dnipro city is located in the center of the region the identified tendencies mainly reflect changes of climatic conditions within the entire Dnipropetrovsk region.


Formulation of the problem. Understanding that solar energy is the main source of the majority of biological, chemical and physical processes on Earth, investigation of its influence on different climatic fields allows us to define the features of its space and hour fluctuations. To define radiation and temperature regime of the territory it is necessary to determine climatic features of the spreading surface, which absorbs and will transform solar energy. Considering the fact that modern climatic changes and their consequences cover all components of the system, today there is a problem of their further study for comprehension of atmospheric processes, modeling weather conditions on different territories depending on the properties. The purpose of the article is to determine interrelations between indexes of solar radiation (the Wolf's number) and air temperature, atmospheric pressure on the territory of Ukraine during 1965-2015, their change in space and time. Methods. Correlative method is one of the main methods of a statistical analysis which allows us to receive correlation coefficients of solar radiation variability indexes, air temperature, atmospheric pressure on the territory of the research. This technique estimates the extent of solar radiation influence on temperature regime of the territory and distribution of atmospheric pressure. Results. Coefficients of correlation, which characterize variability of solar radiation indexes, air temperature and atmospheric pressure on the explored territory have been received by means of statistical correlation analysis method. This technique allows us to estimate the degree and nature of solar radiation influence on a temperature regime of the territory and distribution of atmospheric pressure. It has been defined that direct correlative connection between indexes of solar radiation is characteristic of air temperature and atmospheric pressure fields. Significant statistical dependence between incoming solar radiation on the territory of Ukraine and atmospheric pressure has been noted during the spring and autumn periods mainly at the majority of stations. Between indexes of solar radiation and air temperature the inverse correlative connection in winter will be transformed to a direct connection during the spring and summer periods. Scientific novelty and practical significance. Physical processes, which happen in the atmosphere, are characterized by complex interrelations. For further research it is important to define solar radiation value and the extent of influence on climatic conditions.


Vestnik MGSU ◽  
2021 ◽  
pp. 486-492
Author(s):  
Oleg D. Samarin

Introduction. It is noted that the improvement of the technology for calculating the thermal regime of premises in the conditions of automation of climate systems is still relevant. The aim of the work is to find a universal dependence of the air temperature in the building premises on time in conditions of a jump in heat access or heat loss for the integral law of regulating the compensatory heat flow from microclimate systems. In the form of a scientific hypothesis, we consider the statement about the power nature of such a dependence with the presence of a maximum and an asymptotic tendency to zero. Materials and methods. The study involves the use of basic equations that relate the most significant components of heat flows in rooms serviced by microclimate systems equipped with integrated controllers under conditions of abrupt changes in thermal disturbances. The method of dimension analysis is used to identify dimensionless complexes that are essential for obtaining engineering dependencies, as well as software calculation of sums of infinite series with a given accuracy, numerical solution of nonlinear equations, and the method of power series economization. Results. An analytical expression is found for changes in room temperature under integrated control of climate equipment under conditions of a jump in heat availability, which has the form of an infinite series in degrees of a dimensionless parameter that characterizes the properties of the room and the automation system. A simplified expression for the deviation of air temperature is obtained and a formula for the required control time is derived, as well as its estimation is given on the example of one residential building in the climatic conditions of Moscow. Conclusions. It is shown that the dependence of the air temperature in a room serviced by microclimate systems with integrated controllers on time is represented in a universal dimensionless form, suitable for any objects regardless of their specific characteristics. The previously discovered relationships for the moment of maximum deviation and the value of the dynamic control error depending on the air exchange of the room, the transmission coefficient of the controller and the room’s own heat stability are confirmed and refined.


2021 ◽  
Vol 2105 (1) ◽  
pp. 012013
Author(s):  
Ioannis Maznas

Abstract This document presents measurement results of the ZZ production via Vector Boson Scattering interactions in 139fb −1 of data recorded by the ATLAS detector from pp collisions at s = 13 TeV during LHC Run-II (2015-2018). In this study, 127 candidate events with a fully leptonic final state (ℓℓℓℓjj) have been observed and another 82 events for ℓℓvvjj final state, with a contribution of the purely electroweak ZZjj process estimated to be 20.6 ± 2.5 and 12.3 ± 0.7 events respectively. The measured cross sections were found to be 1.27 ± 0.14fb (1.22 ± 0.35fb) for ℓℓℓℓjj (ℓℓvvjj) in their respective fiducial regions. Using multivariant methods, the EW production of ZZjj events (combining the ℓℓℓℓjj and ℓℓvvjj channels) was measured to have a signal strength of 1.35± 0.34, which leads to a rejection of the no-electroweak hypothesis with a statistical significance of 5.5σ.


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