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1

Assessment of spatiotemporal changes of the length and starting date seasons in the west of Iran

Nazripouya Hadi, Meshram Sarita Gajbhiye, Bahramloo Reza, Sepehri Mehdi, Ali Sk Ajim, Kushwaha Nand Lal, Kiani Harchegani Mahboobeh, Rodrigo-Comino Jesús

Acta Geophysica

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2022

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Vol. 70, no 6

2813--2825

EN

There is evidence that human activities are affecting global dynamics. The consequences of changes in the duration of the annual seasons and daily temperatures will imply drastic impacts on human and natural ecosystems. However, estimations related to the duration of the seasons considering the daily temperatures are scarce and could help to foresee negative effects with irreparable consequences. This study investigates the spatiotemporal variation of length and start date of each annual season based on temperature criteria by analyzing daily data of synoptic stations in western Iran from the period 1977–2015. Our results demonstrated that the starting date of summer shows a tendency advanced and the starting date of winter has been delayed. Moreover, spring is coming earlier. On the other hand, winter ends earlier and fall is delayed, with longer summers and shorter winters as a result. The starting date of summer differs from 0 to 2 d advanced in the southwest of the study area and 4–6 d advanced in the central and southeast parts. The starting date of winter on average has been delayed by 2 days and the length of the season has been shortened by 5 days. The changes for spring and fall are relatively smaller. Particularly, spring started earlier by 4.2 days but was extended by 1.8 days, and the fall season has started delayed by 0.8 days but extended by 0.4 days. This study provides simple information to stakeholders and policymakers so that they should focus on the issue and start developing efficient plans to reduce the negative impacts on the temperatures, shorter winters and the earlier spring, which could affect the floriation and animal behaviors among others.

2

Komory kriogeniczne: sposoby chłodzenia i ich ocena techniczna

Olejniczak Michał

Technika Chłodnicza i Klimatyzacyjna

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2019

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nr 8

279--283

PL

Komory kriogeniczne są obiektami wykorzystywanymi podczas zabiegów krioterapii ogólnoustrojowej. Zabieg taki polega na schłodzeniu całego ciała pacjenta podczas pobytu w takiej komorze w czasie 2-3 minut. Typowe komory kriogeniczne składają się z dwóch części, w ich skład wchodzi przedsionek, nazywany komorą wstępną o temperaturze wewnętrznej -60oC, w którym pacjent aklimatyzuje się do niskich temperatur oraz komora właściwa z temperaturą wewnętrzną regulowaną przez jej obsługę w zakresie od ok. -100°C do -160°C.

EN

For the purpose of cryotherapy low temperature chambers are used. Inside these objects the whole body is cooled for 2-3 minutes. Typical configuration comprises two parts: the preliminary room with -60oC just for acclimation to the very low temperature and the cryogenic chamber itself with temperature controlled in the range of -100°C to -160°C

3

Numerical solutions of steady free convective flow in a rectangular region with discrete wall heat and concentration sources

Ambethkar Vusala, Basumatary Lakshmi Rani

Journal of Applied Mathematics and Computational Mechanics

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2019

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Vol. 18, nr 4

5--18

EN

In this paper, numerical solutions are obtained for steady free convective ﬂow in a rectangular region with discrete wall heat and concentration sources by using the ﬁnite volume method. The governing equations consist of the continuity, momentum, energy and mass transfer. These equations conjointly with suitable boundary conditions are solved numerically by using this method. The novel concept in this work is to generalize the SIMPLE algorithm suitably and thereby compute the numerical solutions of the ﬂow variables such as the temperature (θ) and the concentration (C) in addition to the components of velocity and the pressure. All non-dimensional parameters are chosen suitably in accordance with the physical signiﬁcance of the problem under investigation. With the help of these numerical solutions, we have depicted the proﬁles of the velocity, pressure, temperature and concentration along the horizontal and vertical directions of the geometric centre of the region. The validity of the numerical solutions are ensured by comparing the present solutions with the benchmark solutions. Code validation has been given for the present problem.

4

Fracture toughness analysis of delamineted composites under variable temperatures

El Moufari M., El Bakkali L.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 1

171--178

EN

The main goal of the present paper is to approach the modeling of one of the most important and critical failure modes for composite laminates which is known as interlaminar delamination in the aeronautical structures. The analytical model is based on a fracture mechanics approach; it’s used to estimate the total mixed mode energy release rate for composite laminates. A finite element simulation has been achieved in combination with the virtual crack closure technique (VCCT) to analyze the effect of temperature on the interlaminar fracture toughness growth of a delaminated carbon/epoxy material, namely IM7/8552 subjected to mechanical loading at variable temperatures. The developed model may serve as the basis for treating different types of thermal and mechanical loading, different stacking sequences and thickness of lamina in order to build safe working conditions for composite laminates.

5

Apparatus for Measuring the Bending Fatigue Properties of High Performance Polyethylene Fibre

Cai G., Shi X., Yu W.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 4 (93)

37--40

EN

A test method for bending fatigue has been developed to determine the bending fatigue strength of fibres. This new equipment is capable of performing the bending fatigue testing of fibres under different pre-tensions, bending angles and temperatures. This article presents results from tests on single high performance polyethylene fibre (HPPE) to characterise its bending fatigue behaviour under cyclic loading and temperatures. The curve of the cyclic tension shows that the cyclic tension changes in periods during the cyclic bending process. The S-N and č-N curves indicated that the pre-tension and bending angle had great influences on the bending fatigue life of HPPE fibre. A CCD camera was utilised to allow observation of the bending fatigue fracture morphology of the fibre. It showed the fracture mechanism of the HPPE fibres. The bending fatigue life of HPPE fibre was tested at different temperatures to show that its bending fatigue strength is strongly influenced by the temperature.

PL

Opracowano metodę oceny wytrzymałości zmęczeniowej włókien polietylenowych przy zginaniu. Przewidziano możliwość badania włókien przy rożnym obciążeniu wstępnym, kącie zginania i temperaturze. Przeprowadzono próby badania włókien polietylenowych w różnych temperaturach i przy rożnym kącie zginania. Stwierdzono, że naprężenie zginające zmienia się okresowo podczas cyklicznego procesu zginania. Stwierdzono również, że wstępne naprężenie oraz kąt zginania mają istotny wpływ na wytrzymałość zmęczeniową badanych włókien. Kamerę CCD zastosowano dla obserwacji morfologii przełomu zmęczeniowego włókien, pozwalającego na identyfikację mechanizmu przełomu. Stwierdzono wyraźny wpływ temperatury, w której przeprowadzano próby.

6

Wyznaczanie rozkładu temperatur zaworu dolotowego doładowanego silnika z zapłonem samoczynnym w stanie nieustalonym

Gustof P., Jędrusik D.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2003

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z. 50

7-14

PL

W pracy wyznaczono rozkłady temperatur zaworu dolotowego doładowanego silnika z zapłonem samoczynnym w stanie nieustalonym przy zastosowaniu modelu dwustrefowego procesu spalania oraz metody elementów skończonych (MES) za pomocą programu Cosmos/M.

EN

The thesis determines distribution of temperatures the inlet valve of Diesel turbo engine in an unsteady state performed using model of process of two-zone combustion and the finite elements method (MES) with support of programme Cosmos/M.