scholarly journals Nonuniform Woven Solar Shading Screens: Shading, Mechanical, and Daylighting Performance

2019 ◽  
Vol 11 (20) ◽  
pp. 5652 ◽  
Author(s):  
Yao Lu ◽  
Hankun Lin ◽  
Siwei Liu ◽  
Yiqiang Xiao
Keyword(s):  
Solar Radiation ◽  
Mechanical Performance ◽  
Structural Strength ◽  
Negative Impact ◽  
Optical Performance ◽  
Clear View ◽  
Performance Factors ◽  
Ansys Simulation ◽  
Solar Shading ◽  
Optimal Configurations

This study investigated the potential of using a nonuniform woven panel with nonuniform strips—thick sticks and thin battens—as an external solar shading screen that addressed daylighting, shading, and mechanical performance factors. The sustainable material, namely, bamboo, was used as the demonstration material for the screen. An on-site experiment and ANSYS simulation were carried out to investigate the basic solar optical performance and structural strength of the proposed screen, respectively. Then, a series of daylighting simulations were conducted to optimize the configuration of the screen. The results showed that the nonuniform woven solar shading screen reduced up to 80.3% of the solar radiation gain in a room during summer months while ensuring a relatively even distribution of useful daylight during the year. Moreover, the screen effectively reduced the negative impact of glare to a level below “imperceptible” and enabled a relatively clear view through the window and shading. Regarding the structural strength, the screen with a size smaller than or equal to 1 × 1 m withstood a wind load of 12 m/s. Furthermore, this study proposed two optimal configurations: a screen woven of square sticks and battens with a distance of 10 mm between them, and a screen woven of round sticks and battens with a distance of 8 mm between them. This study illustrated the superiority of the nonuniform woven solar shading screens, which supports a wider application of solar shading screens made of other materials with similar structures and reflectance values.

Variability in Interpreting “Educational Performance” for Children With Speech Sound Disorders

2018 ◽  
Vol 49 (4) ◽  
pp. 938-949 ◽  
Author(s):  
Kelly Farquharson ◽  
Lisa Boldini
Keyword(s):  
United States ◽  
Public Schools ◽  
Negative Impact ◽  
Speech Sound ◽  
Well Being ◽  
The United States ◽  
Educational Performance ◽  
Speech Sound Disorders ◽  
Performance Factors ◽  
State And Local

Purpose Speech sound disorders (SSDs) can have a negative impact on literacy development, social–emotional well-being, and participation across the life span. Despite this, many public schools do not provide appropriate or timely services to this population of children. In large part, this is a result of variation in how state and local agencies interpret “educational performance” as outlined within the Individuals With Disabilities Education Act. The purpose of this study was to explore which educational performance factors speech-language pathologists (SLPs) consider when determining eligibility for children with SSDs. Method This study surveyed public school SLPs to investigate how educational performance is interpreted for children with SSDs. Data from 575 SLPs across the United States are included. Results Results supported variability in interpretation of educational performance within a nationwide sample of SLPs. Specifically, SLPs appear to consider educational performance as multidimensional. We also found within-state and between-states variability, indicating ambiguity in interpreting federal mandates. Finally, caseload size and number of years of experience were significantly related to which educational performance factors SLPs chose. Conclusion There is significant variability across the United States with respect to factors considered part of educational performance for children with SSD. This variability reflects the general quality and specificity of guidelines and/or special education code published by individual states. Clinical and legislative recommendations are included.

scholarly journals A Study on the Effect of Carbon Nanotubes’ Distribution and Agglomeration in the Free Vibration of Nanocomposite Plates

2020 ◽  
Vol 6 (4) ◽  
pp. 79
Author(s):  
D. S. Craveiro ◽  
M. A. R. Loja
Keyword(s):  
Carbon Nanotubes ◽  
Elastic Properties ◽  
Natural Frequencies ◽  
Mechanical Performance ◽  
Negative Impact ◽  
Free Vibrations ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Agglomeration Effect ◽  
Performance Predictions

The present work aimed to characterize the free vibrations’ behaviour of nanocomposite plates obtained by incorporating graded distributions of carbon nanotubes (CNTs) in a polymeric matrix, considering the carbon nanotubes’ agglomeration effect. This effect is known to degrade material properties, therefore being important to predict the consequences it may bring to structures’ mechanical performance. To this purpose, the elastic properties’ estimation is performed according to the two-parameter agglomeration model based on the Eshelby–Mori–Tanaka approach for randomly dispersed nano-inclusions. This approach is implemented in association with the finite element method to determine the natural frequencies and corresponding mode shapes. Three main agglomeration cases were considered, namely, agglomeration absence, complete agglomeration, and partial agglomeration. The results show that the agglomeration effect has a negative impact on the natural frequencies of the plates, regardless the CNTs’ distribution considered. For the corresponding vibrations’ mode shapes, the agglomeration effect was shown in most cases not to have a significant impact, except for two of the cases studied: for a square plate and a rectangular plate with symmetrical and unsymmetrical CNTs’ distribution, respectively. Globally, the results confirm that not accounting for the nanotubes’ agglomeration effect may lead to less accurate elastic properties and less structures’ performance predictions.

scholarly journals Pig behaviour in relation to weather conditions – a review

2015 ◽  
Vol 15 (3) ◽  
pp. 601-610 ◽  
Author(s):  
Katarzyna Olczak ◽  
Jacek Nowicki ◽  
Czesław Klocek
Keyword(s):  
Solar Radiation ◽  
Low Temperatures ◽  
Negative Impact ◽  
Weather Conditions ◽  
Farm Animals ◽  
Semen Parameters ◽  
Wild Pigs ◽  
Resting Behaviour ◽  
Wide Range ◽  
Characteristic Behaviour

Abstract Weather conditions (temperature, humidity, solar radiation, air pressure, wind strength, wind direction and precipitation) have a significant impact on the behaviour of farm animals. Pigs have developed a wide range of thermoregulatory behaviours that are particular for this species. With increases in temperature the most characteristic behaviour for pigs is decreased activity and increased wallowing in wet surfaces. In addition to this, rooting and wallowing are highly influenced by temperature and humidity. The lack of possibility to express these behaviours leads to development of stereotypies. Interestingly, low temperatures do not increase the use of shelter if not in combination with wind or precipitation. Furthermore, wild pigs build stronger nests in severe conditions. Also, resting behaviour and reproduction may be disturbed by high temperatures. There is a negative impact of foehn wind on boars’ libido and semen parameters.

scholarly journals Investigation of the mechanical and thermal characteristics of an eco-insulating material made of plaster and date palm fibers

2021 ◽  
Vol 16 (2) ◽  
pp. 55-66
Author(s):  
Mokhtar Rachedi ◽  
Abdelouahed Kriker
Keyword(s):  
Building Materials ◽  
Date Palm ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Negative Impact ◽  
Low Cost ◽  
Natural Fibers ◽  
Thermal Characteristics ◽  
Chemical Degradation ◽  
Date Palm Fibers

Abstract The negative impact of the production and use of building materials on the environment has become evident, so in recent decades, to find more sustainable, eco-friendly, and low-cost materials, the last research tends to reconsider the use of natural fibers and traditional building materials. This paper aims to develop a bio-composite based on the southern Algerian region's local materials consisting mainly of plaster and waste from date palm trees. Many properties were examined experimentally through previous research of our team (physical, mechanical, and microstructure characteristics) [1, 2] to characterize these materials. Several samples of bio-composite of plaster configurations with short length (20mm) and eight-weight ratios (0.5% - 4%) of palm fibers were prepared for mechanical, thermal, and physical characterizations. In addition, tested all previous properties on the specimens after 28 days of curing in normal conditions. The results show a clear improvement in the bio-composites mechanical performance (an increase in the bending strength with achieving compressive strength) and their thermal properties, which have been well developed (density, thermal conductivity, and specific heat capacity). To enhance the resistance of palm fibers to chemical degradation in the plaster's alkaline environment and improve the adhesion between them, these fibers were treated with a NaOH solution of 1% concentration. The plaster's composites reinforced with date palm fibers can be qualified as eco-friendly and thermal insulation building materials.

scholarly journals Determination of physical characteristics of horizontally positioned solar module in real climate conditions in Nis, Serbia

2016 ◽  
Vol 14 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Lana Pantic ◽  
Tomislav Pavlovic
Keyword(s):  
Solar Radiation ◽  
Ambient Temperature ◽  
Output Power ◽  
Radiation Intensity ◽  
Negative Impact ◽  
Open Circuit ◽  
Physical Characteristics ◽  
Solar Module ◽  
Climate Conditions ◽  
Solar Radiation Intensity

The aim of this paper was to investigate the influence of solar radiation intensity, ambient temperature, wind speed and solar module temperature on the modules physical characteristics, in local climate conditions and for all seasons in Nis, Serbia. Twelve sunny days, for each month of the year, from the period September 2014 - June 2016 were selected. During each day meteorological parameters, solar module temperature and solar module output parameters were measured. The highest values of solar radiation intensity, ambient temperature and solar module temperature were measured in summer months, while the lowest values were in winter months. The maximal values of the output power were measured in summer months due to the high values of solar radiation intensity on the solar modules surface. A negative impact of high solar module temperature on the open circuit voltage, the output power, the fill factor and the efficiency was observed. In the winter months the local climatic conditions and air pollution have an adverse impact on the solar module efficiency and lead to a noticeable reduction of the efficiency.

scholarly journals Concrete with Partial Substitution of Waste Glass and Recycled Concrete Aggregate

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 430
Author(s):  
Jawad Ahmad ◽  
Rebeca Martínez-García ◽  
Jesús de-Prado-Gil ◽  
Kashif Irshad ◽  
Mohammed A. El-Shorbagy ◽  
...  
Keyword(s):  
Performance Test ◽  
Coarse Aggregate ◽  
Mechanical Performance ◽  
Negative Impact ◽  
Strength Properties ◽  
Waste Glass ◽  
Recycled Concrete ◽  
Partial Substitution ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate

The current practice of concrete is thought to be unsuitable because it consumes large amounts of cement, sand, and aggregate, which causes depletion of natural resources. In this study, a step towards sustainable concrete was made by utilizing recycled concrete aggregate (RCA) as a coarse aggregate. However, researchers show that RCA causes a decrease in the performance of concrete due to porous nature. In this study, waste glass (WG) was used as a filler material that filled the voids between RCA to offset its negative impact on concrete performance. The substitution ratio of WG was 10, 20, or 30% by weight of cement, and RCA was 20, 40, and 60% by weight of coarse aggregate. The slump cone test was used to assess the fresh property, while compressive, split tensile, and punching strength were used to assess the mechanical performance. Test results indicated that the workability of concrete decreased with substitution of WG and RCA while mechanical performance improved up to a certain limit and then decreased due to lack of workability. Furthermore, a statical tool response surface methodology was used to predict various strength properties and optimization of RCA and WG.

scholarly journals Thermo-mechanical characterization of a bio-composite mortar reinforced with date palm fiber

2020 ◽  
Vol 15 ◽  
pp. 155892502094823
Author(s):  
Samir Benaniba ◽  
Zied Driss ◽  
Mokhtar Djendel ◽  
Elhadj Raouache ◽  
Rabah Boubaaya
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Building Materials ◽  
Date Palm ◽  
Mechanical Performance ◽  
Negative Impact ◽  
Natural Fibers ◽  
Palm Fiber ◽  
Date Palm Fibers

Due to respect for the environment and the search for more sustainable materials, scientists have started in recent decades to launch studies on bio-composite materials. It is well known that building materials are among the most commonly used materials and have an obvious negative impact on the environment. The development of environmentally friendly composites as insulating materials in buildings offers practical solutions to reduce energy consumption. Therefore, this work presents the use of a new bio-composite material composed of natural fibers, date palm fibers, cement, and sand. In addition, the study on the effect of adding date palm fibers on the thermo-mechanical characteristics of mortars assesses the thermal insulation properties as well as the water absorption and mechanical performance of this new bio-composite material to use it in the construction of buildings. The percentage by weight of date palm fiber in the test samples varied from 0% to 30% for a fiber size of length equal to 7 mm. The characteristics of these samples were determined experimentally in terms of resistance to bending and compression as well as thermal conductivity. The results show that while increasing the weight of date palm fiber, an obviously reduction in thermal conductivity, flexural, and compressive strength of the composite is observed. Hence, date palm fiber has a positive effect on the thermo-mechanical properties of the composite material. Therefore, it considerably improves the insulating capacity of the mortar.

Experimental Research on Effect of Hot Works on Mechanical Performance of Ship Steel Plate

2011 ◽  
Vol 311-313 ◽  
pp. 1859-1862
Author(s):  
Hua Ming Wang ◽  
Han Xing Zhao ◽  
Yong Jia Dai ◽  
Xiao Song Rui
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Steel Plate ◽  
Mechanical Performance ◽  
Structural Strength ◽  
High Strength ◽  
Shipbuilding Industry ◽  
Important Method ◽  
Fairing Process

Hot works is an important method for fairing the ship steel plate to improve the quality of shipbuilding, while the mechanical performance of the ship steel plate may be affected during the fairing process, which could result to some safe problems on the structural strength. DH32 high-strength ship steel plate, which is a kind of widely used material in shipbuilding industry, is taken as an object of the present experimental study. Some main parameters of the plate’s mechanical property through hot-works treatment for different times are investigated systematically. Through analyzing the variation of the mechanical properties, some conclusions are drawn and some useful suggestions put forward.

Structural Design and Analysis of the Toroidal Heliostat

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Chuncheng Zang ◽  
Zhifeng Wang ◽  
Wenfeng Liang ◽  
Xiaoyu Wang
Keyword(s):  
Structural Design ◽  
Mechanical Performance ◽  
Great Influence ◽  
The Sun ◽  
Optical Performance ◽  
The Finite Element Method ◽  
Advantages And Disadvantages ◽  
Property Evaluation ◽  
Solar Power Tower ◽  
The Cost

Heliostat is an important component in the solar power tower station because its cost, optical performance, and mechanical performance have great influence on the overall property evaluation of the station. The T-shape heliostat tracking the sun in the azimuth-elevation mode has been commonly developed and successfully applied in many stations. In recent years, some researchers have developed spinning-elevation heliostats and have analyzed their optical performance. In this paper, the structure of a 16 m2 toroidal heliostat tracking the sun in the spinning-elevation mode is designed, and the mechanical performance of the structure under wind load is analyzed by means of the finite element method. The trends of force, moments, and vibration modes with the change in elevation have been presented, and the classic status is analyzed in detail when their maximum values occur. Furthermore, the advantages and disadvantages of a toroidal heliostat in reducing the cost are discussed compared with those of a traditional T-shape heliostat.

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