scholarly journals Estimating thermal transmittance of the aluminium window profiles in practice

2020 ◽  
Vol 172 ◽  
pp. 24003
Author(s):  
Arkadiusz Witek ◽  
Barbara Pietruszka
Keyword(s):  
Heat Exchange ◽  
Accurate Method ◽  
Radiative Heat Exchange ◽  
Conductivity Method ◽  
Equivalent Thermal Conductivity ◽  
Thermal Transmittance ◽  
Radiation Exchange ◽  
First Case ◽  
Air Cavities ◽  
The Impact

Calculation of the heat flow through the air cavities in the EN ISO 10077-2:2017 standard for the determination of the thermal transmittance of window profiles uses models based on the equivalent thermal conductivity method. The method takes into account the radiative heat exchange in a simplified or accurate manner. In the first case, the heat exchange depends on the average temperature in cavity, in the second case - it is determined accurately by the ray tracing method. It is also of importance to differentiate emissivity of surfaces due to aging or painting what influences calculation time. In this work, the impact of the calculation method and the impact of simplifications in modelling of the untreated surfaces on the value of the thermal transmittance of aluminium profiles was analysed on the example of a real series of products. Comparing the simplified and accurate method of determining the radiation exchange in cavities, the differences in the thermal transmittances of window profiles were up to 22%. The differences between the most simplified and the most accurate modelling of the surfaces emissivity reached 23%.

Impact of hydroxychloroquin/azithromycin protocol on COVID-19 case-fatality rate reduction in Algeria. (Preprint)

2020 ◽  
Author(s):  
Ahmed Youssef Kada
Keyword(s):  
Case Fatality Rate ◽  
Doubling Time ◽  
Case Fatality ◽  
World Health ◽  
Fatality Rate ◽  
Therapeutic Protocol ◽  
First Case ◽  
The World ◽  
The Impact ◽  
At Home

BACKGROUND Covid-19 is an emerging infectious disease like viral zoonosis caused by new coronavirus SARS CoV 2. On December 31, 2019, Wuhan Municipal Health Commission in Hubei province (China) reported cases of pneumonia, the origin of which is a new coronavirus. Rapidly extendable around the world, the World Health Organization (WHO) declares it pandemic on March 11, 2020. This pandemic reaches Algeria on February 25, 2020, date on which the Algerian minister of health, announced the first case of Covid-19, a foreign citizen. From March 1, a cluster is formed in Blida and becomes the epicentre of the coronavirus epidemic in Algeria, its total quarantine is established on March 24, 2020, it will be smoothly alleviated on April 24. A therapeutic protocol based on hydroxychloroquine and azithromycin was put in place on March 23, for complicated cases, it was extended to all the cases confirmed on April 06. OBJECTIVE This study aimed to demonstrate the effectiveness of hydroxychloroquin/azithromycin protocol in Algeria, in particular after its extension to all patients diagnosed COVID-19 positive on RT-PCR test. We were able to illustrate this fact graphically, but not to prove it statistically because the design of our study, indeed in the 7 days which followed generalization of therapeutic protocol, case fatality rate decrease and doubling time increase, thus confirming the impact of wide and early prescription of hydroxychloroquin/azithromycin protocol. METHODS We have analyzed the data collected from press releases and follow-ups published daily by the Ministry of Health, we have studied the possible correlations of these data with certain events or decisions having a possible impact on their development, such as confinement at home and its reduction, the prescription of hydroxychloroquine/azithromycin combination for serious patients and its extension to all positive COVID subjects. Results are presented in graphics, the data collection was closed on 31/05/2020. RESULTS Covid-19 pandemic spreads from February 25, 2020, when a foreign citizen is tested positive, on March 1 a cluster is formed in the city of Blida where sixteen members of the same family are infected during a wedding party. Wilaya of Blida becomes the epicentre of coronavirus epidemic in Algeria and lockdown measures taken, while the number of national cases diagnosed begins to increases In any event, the association of early containment measures combined with a generalized initial treatment for all positive cases, whatever their degree of severity, will have contributed to a reduction in the fatality rate of COVID 19 and a slowing down of its doubling time. CONCLUSIONS In Algeria, the rapid combination of rigorous containment measure at home and early generalized treatment with hydroxychloroquin have demonstrated their effectiveness in terms of morbidity and mortality, the classic measures of social distancing and hygiene will make it possible to perpetuate these results by reducing viral transmission, the only unknown, the reopening procedure which can only be started after being surrounded by precautions aimed at ensuring the understanding of the population. CLINICALTRIAL Algeria, Covid-19, pandemic, hydroxychloroquin, azithromycin, case fatality rate

scholarly journals A Case of COVID-19-Related Thrombocytopenia and Leukopenia in an Adolescent with Mild Symptoms

Children ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 509
Author(s):  
Lydia Kossiva ◽  
Athanasios Thirios ◽  
Eleni Panagouli ◽  
Alexandros Panos ◽  
Stavroula Lampidi ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Viral Infection ◽  
Nasal Congestion ◽  
Pediatric Population ◽  
Clinical Manifestations ◽  
Bone Marrow Aspiration ◽  
White Blood Count ◽  
Chronic Obstructive ◽  
First Case ◽  
The Impact

Since the beginning of the COVID-19 pandemic, there have been numerous reports and reviews on the complications caused by the disease, analyzing the acute and chronic consequences. The main symptoms of SARS-CoV-2 are dry cough, fever, and fatigue. COVID-19 appears to affect all systems, including renal, cardiovascular, circulatory, and respiratory systems, causing chronic obstructive pulmonary disease. We report on a 14-year-old male adolescent, who presented with thrombocytopenia (platelet count 92 × 109 /L) and leukopenia (white blood count 4.2 × 103 /μL) that was observed two months ago. Ten days before the first blood test, a viral infection with nasal congestion and runny nose was reported, without other accompanying symptoms. Viral antibodies screening revealed positivity for all the three specific COVID-19 antibodies. Further haematological evaluation with bone marrow aspiration revealed non-specific dysplastic features of the red cell and megakaryocyte progenitors. Although haematological alterations due to COVID-19 infection are available from adult patients’ reports, the effect of COVID-19 infection in the pediatric population is underestimated and this is the first case with such haematological involvement. Noteworthy, in the current case, the impact of the COVID-19 infection was not related to the severity of the disease, as the symptoms were mild. In similar cases, bone marrow aspiration would not be performed as a part of routine work-up. Thus, it is important when evaluating pediatric patients with COVID-19 infection to search and report those alterations in order to better understand the impact and the spectrum of clinical manifestations of the specific viral infection in children and adolescents.

RESPONSE OF STOCK MARKET DURING COVID-19 AND 2008 FINANCIAL CRISIS: A COMPARATIVE EVIDENCE FROM BRICS NATIONS

2021 ◽  
pp. 1-24
Author(s):  
SANJEEV KUMAR ◽  
JASPREET KAUR ◽  
MOSAB I. TABASH ◽  
DANG K. TRAN ◽  
RAJ S DHANKAR
Keyword(s):  
South Africa ◽  
Financial Crisis ◽  
Stock Market ◽  
Stock Returns ◽  
Stock Markets ◽  
2008 Financial Crisis ◽  
First Case ◽  
Egarch Model ◽  
The 2008 Financial Crisis ◽  
The Impact

This study attempts to examine the response of stock markets amid the COVID-19 pandemic on prominent stock markets of the BRICS nation and compare it with the 2008 financial crisis by employing the GARCH and EGARCH model. First, average and variance of stock returns are tested for differences before and after the pandemic, t-test and F-test were applied. Further, OLS regression was applied to study the impact of COVID-19 on the standard deviation of returns using daily data of total cases, total deaths, and returns of the indices from the date on which the first case was reported till June 2020. Second, GARCH and EGARCH models are employed to compare the impact of COVID-19 and the 2008 financial crisis on the stock market volatility by using the data of respective stock indices for the period 2005–2020. The results suggest that the increasing number of COVID-19 cases and reported death cases hurt stock markets of the five countries except for South Africa in the latter case. The findings of the GARCH and EGARCH model indicate that for India and Russia, the financial crisis of 2008 has caused more stock volatility whereas stock markets of China, Brazil, and South Africa have been more volatile during the COVID-19 pandemic. The study has practical implications for investors, portfolio managers, institutional investors, regulatory institutions, and policymakers as it provides an understanding of stock market behavior in response to a major global crisis and helps them in taking decisions considering the risk of these events.

Effect of Buoyancy and Density Ratio on Heat Transfer in a Smooth Cooling Channel of a Gas Turbine Blade

2018 ◽  
Author(s):  
Mandana S. Saravani ◽  
Saman Beyhaghi ◽  
Ryoichi S. Amano
Keyword(s):  
Heat Transfer ◽  
Rotational Speed ◽  
Cfd Simulation ◽  
Density Ratio ◽  
Reynolds Numbers ◽  
Buoyancy Effect ◽  
Square Channel ◽  
First Case ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact

The present work investigates the effects of buoyancy and density ratio on the thermal performance of a rotating two-pass square channel. The U-bend configuration with smooth walls is selected for this study. The channel has a square cross-section with a hydraulic diameter of 5.08 cm (2 inches). The lengths of the first and second passes are 514 mm and 460 mm, respectively. The turbulent flow enters the channel with Reynolds numbers of up to 34,000. The rotational speed varies from 0 to 600 rpm with the rotational numbers up to 0.75. For this study, two approaches are considered for tracking the buoyancy effect on heat transfer. In the first case, the density ratio is set constant, and the rotational speed is varied. In the second case, the density ratio is changed in the stationary case, and the effect of density ratio is discussed. The range of Buoyancy number along the channel is 0–6. The objective is to investigate the impact of Buoyancy forces on a broader range of rotation number (0–0.75) and Buoyancy number scales (0–6), and their combined effects on heat transfer coefficient for a channel with aspect ratio of 1:1. Several computational fluid dynamics (CFD) simulation are carried out for this study, and some of the results are validated against experimental data.

scholarly journals Thermal bridge effect of vertical diagonal tie connectors in precast concrete sandwich panels: an experimental and computational study

2020 ◽  
Vol 172 ◽  
pp. 08001
Author(s):  
Paul Klõšeiko ◽  
Reimo Piir ◽  
Marti Jeltsov ◽  
Targo Kalamees
Keyword(s):  
Computational Study ◽  
Precast Concrete ◽  
Sandwich Panels ◽  
Building Envelope ◽  
Heat Fluxes ◽  
Air Cavity ◽  
Thermal Transmittance ◽  
Thermal Bridge ◽  
Thermal Bridging ◽  
Air Cavities

The purpose of this work was to quantify the thermal bridge effect of vertical diagonal tie connectors in precast concrete sandwich panels (PCSPs). Special interest was in cases where the use of rigid insulation (e.g. PIR) would leave air gaps between insulation boards and diagonal ties, thus intensifying the thermal bridge. A climate chamber experiment using 5 different joint types was performed to gather reference data for CFD model validation. In the experiment, natural convection was observed in joints where no additional insulation was used, i.e. in air cavities. Significantly larger heat fluxes were measured in these cavities compared to insulated joints. The thermal bridging effect was evaluated for a typical PCSP (thermal transmittance without thermal bridges U = 0.11 W/(m²·K)) using CFD software taking into account 3D heat conduction and convection. Simulation results indicate that diagonal ties without adjacent air cavities increased the average thermal transmittance (U-value) of the envelope by 8%, diagonal ties with a 6 mm air cavity – 19...33% and diagonal ties with a 10 mm air cavity – 45...56%. In conclusion, it was found that the joints in insulation caused by diagonal ties affect the overall thermal performance of the building envelope significantly when efforts are not made to fill the air cavities around the connectors.

scholarly journals PEMBERDAYAAN MASYARAKAT MELALUI BUDIDAYA JAMUR TIRAM UNTUK MEWUJUDKAN KEMANDIRIAN BERWIRAUSAHA DI ERA NEW NORMAL PADA KELOMPOK WANITA TANI (KWT) MAJU BERSAMA DUSUN PELEMPAT KABUPATEN LOMBOK BARAT

2021 ◽  
Vol 1 (1) ◽  
pp. 1-10
Author(s):  
Mey Susanti AS ◽  
Dewi Rispawati ◽  
Basuki Srihermanto ◽  
Suryaningsih
Keyword(s):  
Health Sector ◽  
Monitoring And Evaluation ◽  
Women Farmers ◽  
New Normal ◽  
Community Activities ◽  
First Case ◽  
The Family ◽  
High Motivation ◽  
The Government ◽  
The Impact

Indonesia reported the first case of Covid-19 on March 2, 2020. Data as of March 31, 2020 showed that there were 1.528 confirmed cases and 136 deaths. The Covid-19 death rate in Indonesia is 8.9%, the highest in Southeast Asia. After confirming the first case, the Government of Indonesia took various countermeasures to reduce the impact of the Covid-19 pandemic in various sectors. Not only the health sector but also the economic sector has suffered no less serious impacts due to this pandemic. At the family level, the small and middle levels of society become weak and decline, this is due to restrictions on community activities. Due to these conditions, it is necessary to make efforts that we must do to be able to restore the economic condition of the family by utilizing the potential that exists around it. This service was carried out at the Women Farmers Group called ‘Kelompok Wanita Tani (KWT) Maju Bersama’  Pelempat, Meninting Village, West Lombok District, West Nusa Tenggara Province. The method used in this activity is implemented in 4 (four) activity stages, namely 1) Preparation, 2) Socialization, 3) Activity Implementation, and 4) Monitoring and Evaluation. The results of the activity showed that members of  Kelompok Wanita Tani (KWT) Maju Bersama have understood the technique of developing oyster mushroom cultivation and have high motivation to become entrepreneurs through cultivating oyster mushrooms as well as making it to increase people's income in the New Normal Era of the Covid-19 pandemic.

scholarly journals Estimating COVID-19 cases in Makkah region of Saudi Arabia: Space-time ARIMA modeling

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250149
Author(s):  
Fuad A. Awwad ◽  
Moataz A. Mohamoud ◽  
Mohamed R. Abonazel
Keyword(s):  
Saudi Arabia ◽  
Moving Average ◽  
Arima Model ◽  
Daily Basis ◽  
World Health ◽  
Arima Models ◽  
Autoregressive Integrated Moving Average ◽  
First Case ◽  
Novel Coronavirus ◽  
The Impact

The novel coronavirus COVID-19 is spreading across the globe. By 30 Sep 2020, the World Health Organization (WHO) announced that the number of cases worldwide had reached 34 million with more than one million deaths. The Kingdom of Saudi Arabia (KSA) registered the first case of COVID-19 on 2 Mar 2020. Since then, the number of infections has been increasing gradually on a daily basis. On 20 Sep 2020, the KSA reported 334,605 cases, with 319,154 recoveries and 4,768 deaths. The KSA has taken several measures to control the spread of COVID-19, especially during the Umrah and Hajj events of 1441, including stopping Umrah and performing this year’s Hajj in reduced numbers from within the Kingdom, and imposing a curfew on the cities of the Kingdom from 23 Mar to 28 May 2020. In this article, two statistical models were used to measure the impact of the curfew on the spread of COVID-19 in KSA. The two models are Autoregressive Integrated Moving Average (ARIMA) model and Spatial Time-Autoregressive Integrated Moving Average (STARIMA) model. We used the data obtained from 31 May to 11 October 2020 to assess the model of STARIMA for the COVID-19 confirmation cases in (Makkah, Jeddah, and Taif) in KSA. The results show that STARIMA models are more reliable in forecasting future epidemics of COVID-19 than ARIMA models. We demonstrated the preference of STARIMA models over ARIMA models during the period in which the curfew was lifted.

scholarly journals The Impact of ‘Stay At Home’ Orders on Emergency Room Admissions

2020 ◽  
Vol 18 (3) ◽  
pp. 165-169
Author(s):  
Abdullah Osman Kocak ◽  
◽  
Sinem Dogruyol ◽  
Ilker Akbas ◽  
Bugra Kerget ◽  
...  
Keyword(s):  
Emergency Room ◽  
Retrospective Cohort ◽  
Geriatric Patients ◽  
Demographic Data ◽  
Admission Diagnosis ◽  
The Public ◽  
Hospitalization Rates ◽  
First Case ◽  
Novel Coronavirus ◽  
The Impact

Introduction. The 2019-novel-coronavirus (2019-nCoV) outbreak has become a common problem for the whole world. Aim. To investigate the impact of the 2019-nCoV pandemic period in our country on emergency room admissions. Materials and methods. The study was designed as a retrospective cohort. The first case of pneumonia infected with nCoV in our country was diagnosed on March 11, 2020. Considering the date of March 11, 2020, emergency room admissions for two periods of 7 days were investigated, pre-COVID-19 and COVID19. Demographic data, admission diagnosis, vital findings, stay times in emergency room, terminations and emergency department mortality examined. A group of ‘geriatric’ patient populations were created to examine the admission characteristics of patients aged-65 and over. Results. The 3466 patients included in the study. The average number of daily admissions was significantly higher in the pre-COVID-19 period (350.4 ± 54.5), compared to the COVID-19 period (144.7 ± 20.2, p=0001). While the proportion of cardiac- caused admissions increased during the COVID period, the proportion of gastrointestinal-induced admissions decreased (p<0001). Hospitalization rates for both adult and geriatric patients increased during the COVID period (p<0001). Conclusion. Despite all the negativity caused by the outbreak, this period has been one in which the public is aware of unnecessary emergency room which has been subsequently lessened.

scholarly journals Fachadas vidriadas: cálculo de transmitancia térmica

2021 ◽  
Vol 11 (1) ◽  
pp. 08-19
Author(s):  
Maureen de Gastines ◽  
◽  
Andrea Pattini
Keyword(s):  
Numerical Calculation ◽  
Energy Demand ◽  
Design Parameters ◽  
Thermal Transmittance ◽  
Operational Energy ◽  
Glazed Facade ◽  
Profile Design ◽  
Contemporary Architecture ◽  
The Impact

Glazing is one of the dominant features of modern and contemporary architecture. This envelope design may have a great impact on operational energy demand of buildings. In this work, glazed façade systems available in Argentina are analyzed, with the purpose of determining the associated thermal transmittance ranges, in terms of the profiles’ design, the type of glazing and the size of glass panes. First, by using bidimensional numerical calculation, the impact of several profile design parameters on thermal transmittance is studied, highlighting the relevance of glazing fixing methods, to then calculate the thermal transmittance of the entire facade. The results indicate that the thermal transmittance value of glazed facades, mainly depends on the transmittance of the glass used, and exceeds this by 24% on average.

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