scholarly journals Moisture transfer modelling in polystyrene mortar with consideration of sorption hysteresis

2019 ◽  
Vol 128 ◽  
pp. 07006 ◽  
Author(s):  
Maroua Maaroufi ◽  
Kamilia Abahri ◽  
Fares Bennai ◽  
Rafik Belarbi
Keyword(s):  
Air Quality ◽  
Numerical Analysis ◽  
Relative Humidity ◽  
Significant Influence ◽  
Moisture Transfer ◽  
The Other ◽  
Hysteresis Phenomenon ◽  
Indoor Climate ◽  
Sorption Hysteresis ◽  
Transfer Modelling

The walls of buildings experience heat, air and moisture transfers. These transfers have a significant influence on indoor climate, since they affect the value of temperature and relative humidity inhouses. High levels of humidity lead to pathologies in the buildings, and influence the air quality and the hygrothermal comfort of the occupants. In this work, a numerical analysis of the behaviour of polystyrene mortar under hydric solicitations was led. The simulations were held using ComsolMultiphysics and MATLAB. There were two different moisture transfer models used in this work: the first one took into account sorption hysteresis phenomenon, and the other one did not. The computed results showed that considering sorption hysteresis in modelling the hydric behaviour of the material allows obtaining more accurate results comparing to a model that does not consider hysteresis.

3D Modelling of Hydric Transfers in Spruce Wood with Consideration of Sorption Hysteresis

2022 ◽  
Author(s):  
Maroua Maaroufi ◽  
Kamilia Abahri ◽  
Alexandra Bourdot ◽  
Chady El Hachem
Keyword(s):  
Building Materials ◽  
3D Modelling ◽  
The Other ◽  
Hysteresis Phenomenon ◽  
Construction Sector ◽  
Environmental Footprint ◽  
Total Energy Consumption ◽  
Acoustic Insulation ◽  
Spruce Wood ◽  
Sorption Hysteresis

Buildings are responsible for a large portion of the total energy consumption, and have a heavy environmental impact. Wood is one of the most used bio-based building materials, as it helps reducing the environmental footprint of the construction sector. Spruce wood is widely available in France and therefore massively used in buildings. It has interesting thermal and acoustic insulation performances and a good hydric regulation property. Spruce wood microstructure is highly heterogeneous and multiphasic, which makes it harder to apprehend. On the other hand, sorption hysteresis phenomenon is responsible for the moisture accumulation in porous building materials. It is often neglected in hygrothermal transfers modelling, which leads to incorrect water content values. The aim of this work is to investigate the influence of the sorption hysteresis phenomenon on the hydric transfers of spruce wood. The heterogeneity of the microstructure is also considered through 3D tomographic reconstructions included in the modelling.

THE EFFECT OF EVENT AND PUBLICITY TOWARDS BRAND AWARENESS ON FINANCIAL SERVICE AUTHORITY (OJK)

2017 ◽  
Vol 2 ◽  
pp. 281-292
Author(s):  
Donant Alananto Iskandar ◽  
Siti Dewi Sri Ratna Sari
Keyword(s):  
Public Relations ◽  
Significant Influence ◽  
Quantitative Method ◽  
Statistical Approach ◽  
Financial Service ◽  
The Other ◽  
Brand Awareness ◽  
Financial Service Authority ◽  
Other Hand ◽  
The People

This study aims to find out the effect of event and publicity towards brand awareness on Indonesia Financial Service Authority, usually called with its abbreviation OJK. The research background is because OJK was newly established as a financial service authority, replacing Bank Indonesia. Therefore, exploring the awareness of the people about the function of OJK is interesting to be a research subject.This method used in this study is the quantitative method with 82 samples as the questionnaire respondents. The population chosen was an OJK’s event held at LPPI and Indonesia Banking School with 122 participants. Validity, reliability, normality, multicollinearity, heteroskedasticity, correlation, determination, regression, hypothesis and ANOVA tests are used as a statistical approach in order to define the outcome of the survey. The results of this study are both event and publicity have a positive and a significant influence towards brand awareness partially and simultaneously. As the conclusion, OJK should continue its programs. On the other hand, OJK should find another public relations strategy to accelerate people awareness about the duties of OJK. Keywords: Event, Publicity, Brand Awareness

scholarly journals Identifying key processes and sectors in the interaction between climate and socio-economic systems: a review toward integrating Earth–human systems

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kaoru Tachiiri ◽  
Xuanming Su ◽  
Ken’ichi Matsumoto
Keyword(s):  
Ecosystem Services ◽  
Gross Domestic Product ◽  
Significant Influence ◽  
Ghg Emissions ◽  
Climate Impacts ◽  
Ecological Impacts ◽  
The Other ◽  
Economic Damage ◽  
Economic Systems ◽  
The Impact

AbstractFor the purpose of identifying the key processes and sectors involved in the interaction between Earth and socio-economic systems, we review existing studies on those processes/sectors through which the climate impacts socio-economic systems, which then in turn affect the climate. For each process/sector, we review the direct physical and ecological impacts and, if available, the impact on the economy and greenhouse gas (GHG) emissions. Based on this review, land sector is identified as the process with the most significant impact on GHG emissions, while labor productivity has the largest impact on the gross domestic product (GDP). On the other hand, the energy sector, due to the increase in the demand for cooling, will have increased GHG emissions. Water resources, sea level rise, natural disasters, ecosystem services, and diseases also show the potential to have a significant influence on GHG emissions and GDP, although for most of these, a large effect was reported only by a limited number of studies. As a result, more studies are required to verify their influence in terms of feedbacks to the climate. In addition, although the economic damage arising from migration and conflict is uncertain, they should be treated as potentially damaging processes.

The Numerical Analysis of the Velocity and Pressure Distribution of the Oil Film in Heavy Hydrostatic Thrust Bearing

2014 ◽  
Vol 541-542 ◽  
pp. 658-662
Author(s):  
Jian Li ◽  
Yuan Chen ◽  
Yang Chun Yu ◽  
Zhu Xin Tian ◽  
Yu Huang
Keyword(s):  
Mathematical Model ◽  
Numerical Analysis ◽  
Pressure Distribution ◽  
Working Conditions ◽  
Thrust Bearing ◽  
Rotation Speed ◽  
The Other ◽  
Surface Load ◽  
Oil Film ◽  
Volume Method

To study the velocity and pressure distribution of the oil film in a heavy hydrostatic thrust bearing, a mathematical model of the velocity is proposed and the finite volume method (FVM) has been used to simulate the flow field under different working conditions. Some pressure experiments were carried out and the results verified the correctness of the simulation. It is concluded that the pressure distribution varies small under different rotation speed when the surface load on the workbench is constant. But the velocity of the oil film is influenced greatly by the rotation speed. When the rotation speed of the workbench is as quick as enough, the velocity of the oil film on one radial side of the pad will be zero, that is to say the lubrication oil will be drained from the other three sides of the recess.

scholarly journals Influence of Ceramic Particles Character on Resulted Properties of Zinc-Hydroxyapatite/Monetite Composites

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 499
Author(s):  
Klára Hosová ◽  
Jan Pinc ◽  
Andrea Školáková ◽  
Vilém Bartůněk ◽  
Petr Veřtát ◽  
...  
Keyword(s):  
Significant Influence ◽  
Degradation Rate ◽  
Point Of View ◽  
The Other ◽  
Ceramic Particles ◽  
Biological Aspects ◽  
Strength And Ductility

Zinc and its alloys seem to be promising candidates for biodegradable applications. Those materials are often modified by other elements or compounds in order to enhance their properties. The combination of zinc and apatites is challenging for several reasons. However, the advantages connected with the biological aspects suggest the need for further research into such materials. In this study, three zinc-based composites with 4 and 8 wt. % of nanohydroxyapatite or nanomonetite (Zn-4MO, Zn-4HA, Zn-8HA) were prepared by sintering and subsequent extrusion. Materials prepared in this way were characterized from the microstructural, mechanical and corrosion point of view. The obtained results showed a significant influence of particle character (amount and morphology) on the strength and ductility of the prepared materials. In case of Zn-4MO, the presence of monetite significantly increased the ductility compared with the other materials. In addition, the increment of the degradation rate caused by the presence of monetite was observed as well. All obtained results pointed out to significant advantages of monetite for the preparation of Zn-apatite composites compared with hydroxyapatite.

scholarly journals Air Ventilation Performance of School Classrooms with Respect to the Installation Positions of Return Duct

2021 ◽  
Vol 13 (11) ◽  
pp. 6188
Author(s):  
Sungwan Son ◽  
Choon-Man Jang
Keyword(s):  
Air Quality ◽  
Numerical Analysis ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Three Dimensional ◽  
Cross Infection ◽  
School Students ◽  
Height Range ◽  
Air Ventilation ◽  
Ventilation Performance

For students, who spend most of their time in school classrooms, it is important to maintain indoor air quality (IAQ) to ensure a comfortable and healthy life. Recently, the ventilation performance for indoor air quality in elementary schools has emerged as an important social issue due to the increase in the number of days of continuous high concentrations of particulate matter. Three-dimensional numerical analysis has been introduced to evaluate the indoor airflow according to the installation location of return diffusers. Considering the possibility of the cross-infection of infectious diseases between students due to the direction of airflow in the classroom, the airflow angles of the average respiratory height range of elementary school students, between 1.0 and 1.5 m, are analyzed. Throughout the numerical analysis inside the classroom, it is found that the floor return system reduces the indoor horizontal airflow that causes cross-infection among students by 20% compared to the upper return systems. Air ventilation performance is also analyzed in detail using the results of numerical simulation, including streamlines, temperature and the age of air.

scholarly journals Developing Relative Humidity and Temperature Corrections for Low-Cost Sensors Using Machine Learning

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3338
Author(s):  
Ivan Vajs ◽  
Dejan Drajic ◽  
Nenad Gligoric ◽  
Ilija Radovanovic ◽  
Ivan Popovic
Keyword(s):  
Machine Learning ◽  
Air Quality ◽  
Relative Humidity ◽  
Low Cost ◽  
Quality Monitoring ◽  
Air Quality Monitoring ◽  
Lower Accuracy ◽  
Wide Range ◽  
The Impact ◽  
Monitoring Stations

Existing government air quality monitoring networks consist of static measurement stations, which are highly reliable and accurately measure a wide range of air pollutants, but they are very large, expensive and require significant amounts of maintenance. As a promising solution, low-cost sensors are being introduced as complementary, air quality monitoring stations. These sensors are, however, not reliable due to the lower accuracy, short life cycle and corresponding calibration issues. Recent studies have shown that low-cost sensors are affected by relative humidity and temperature. In this paper, we explore methods to additionally improve the calibration algorithms with the aim to increase the measurement accuracy considering the impact of temperature and humidity on the readings, by using machine learning. A detailed comparative analysis of linear regression, artificial neural network and random forest algorithms are presented, analyzing their performance on the measurements of CO, NO2 and PM10 particles, with promising results and an achieved R2 of 0.93–0.97, 0.82–0.94 and 0.73–0.89 dependent on the observed period of the year, respectively, for each pollutant. A comprehensive analysis and recommendations on how low-cost sensors could be used as complementary monitoring stations to the reference ones, to increase spatial and temporal measurement resolution, is provided.

SPECTRAL APPROXIMATION OF A SCHRÖDINGER TYPE EQUATION

1994 ◽  
Vol 04 (01) ◽  
pp. 49-88 ◽  
Author(s):  
CHRISTINE BERNARDI ◽  
MARIE-CLAUDE PELISSIER
Keyword(s):  
Numerical Analysis ◽  
Type Equation ◽  
Neumann Boundary ◽  
Rectangular Domain ◽  
The Other ◽  
Well Posedness ◽  
Discrete Problem ◽  
Spectral Approximation ◽  
Numerical Tests ◽  
Continuous Problem

This paper deals with a linear Schrödinger type equation in a rectangular domain with mixed Dirichlet-Neumann boundary conditions. The well-posedness of the continuous problem is proved, then a discrete problem is defined by combining a Legendre type spectral method in the first direction and a leap-frog scheme in the other one. The numerical analysis of the discretization is performed and error estimates are given. Numerical tests are presented.

Design and topological optimization of rear pressure bulkhead for a typical aircraft

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Marshal Thakran ◽  
Meenakshi ◽  
Jitender Sharma ◽  
Charles Gilbert Martin
Keyword(s):  
Numerical Analysis ◽  
Significant Influence ◽  
Design Methodology ◽  
Structural Integrity ◽  
Topological Optimization ◽  
Content Type ◽  
Iterative Design ◽  
Practical Implications ◽  
Insight Into ◽  
Selection Of

Purpose The purpose of this paper is to evaluate the model of a rear pressure bulkhead with different design optimizations to meet the pressurized cabin requirements of an aircraft. Design/methodology/approach This paper presents the results of the static analysis of a dome-shaped rear pressure bulkhead model designed in Catia-v5. Numerical analysis of model meshed in hyper-mesh and solved using Opti-Struct for iterative design optimizations. Findings All the iterative models are analyzed at 9 Psi. Rear pressure bulkhead designed with L-section stringer shows better results than the model optimized with T-section stringer for the same thickness. The model optimized with L-shaped stinger also reduces the weight of the bulkhead without affecting the structural integrity. Practical implications It has been concluded in this paper that the selection of specific shapes of the stringers shows a significant influence on weight reduction. Originality/value This paper provides a topical, technical insight into the design and development of a rear pressure bulkhead. It also outlines the future development of dome-shaped rear pressure bulkhead.

IAGOS Research Infrastructure for Global-Scale Atmosphere Monitoring by Instrumented Passenger Aircraft

2021 ◽  
Author(s):  
Andreas Petzold ◽  
Valerie Thouret ◽  
Christoph Gerbig ◽  
Andreas Zahn ◽  
Martin Gallagher ◽  
...  
Keyword(s):  
Climate Change ◽  
Air Quality ◽  
Relative Humidity ◽  
Water Vapour ◽  
Research Infrastructure ◽  
Good Resolution ◽  
European Research ◽  
Commercial Aircraft ◽  
High Quality

<p>IAGOS (www.iagos.org) is a European Research Infrastructure using commercial aircraft (Airbus A340, A330, and soon A350) for automatic and routine measurements of atmospheric composition including reactive gases (ozone, carbon monoxide, nitrogen oxides, volatile organic compounds), greenhouse gases (water vapour, carbon dioxide, methane), aerosols and cloud particles along with essential thermodynamic parameters. The main objective of IAGOS is to provide the most complete set of high-quality essential climate variables (ECV) covering several decades for the long-term monitoring of climate and air quality. The observations are stored in the IAGOS data centre along with added-value products to facilitate the scientific interpretation of the data. IAGOS began as two European projects, MOZAIC and CARIBIC, in the early 1990s. These projects demonstrated that commercial aircraft are ideal platforms for routine atmospheric measurements. IAGOS then evolved as a European Research Infrastructure offering a mature and sustainable organization for the benefits of the scientific community and for the operational services in charge of air quality and climate change issues such as the Copernicus Atmosphere Monitoring Services (CAMS) and the Copernicus Climate Change Service (C3S). IAGOS is also a contributing network of the World Meteorological Organization (WMO).</p> <p>IAGOS provides measurements of numerous chemical compounds which are recorded simultaneously in the critical region of the upper troposphere – lower stratosphere (UTLS) and geographical regions such as Africa and the mid-Pacific which are poorly sampled by other means. The data are used by hundreds of groups worldwide performing data analysis for climatology and trend studies, model evaluation, satellite validation and the study of detailed chemical and physical processes around the tropopause. IAGOS data also play an important role in the re-assessment of the climate impact of aviation.</p> <p>Most important in the context of weather-related research, IAGOS and its predecessor programmes provide long-term observations of water vapour and relative humidity with respect to ice in the UTLS as well as throughout the tropospheric column during climb-out and descending phases around airports, now for more than 25 years. The high quality and very good resolution of IAGOS observations of relative humidity over ice are used to better understand the role of water vapour and of ice-supersaturated air masses in the tropopause region and to improve their representation in numerical weather and climate forecasting models. Furthermore, CAMS is using the water vapour vertical profiles in near real time for the continuous validation of the CAMS atmospheric models. </p>

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