Sunlight exposure: the effects on the performance of paragliding fabric

2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Air Permeability ◽  
Sunlight Exposure ◽  
Test Results ◽  
Coating Materials ◽  
Strength Tests ◽  
Before And After ◽  
The Relationship ◽  
Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

Size Effect on Mechanical Properties of LVL

2014 ◽  
Vol 887-888 ◽  
pp. 824-829
Author(s):  
Qing Fang Lv ◽  
Ji Hong Qin ◽  
Ran Zhu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Size Effect ◽  
Tensile Test ◽  
Compression Test ◽  
Test Results ◽  
Laminated Veneer Lumber ◽  
Object Of Study ◽  
The Relationship

Laminated veneer lumber is taken as an object of study, and use LVL specimens of different sizes for compression test and tensile test. The goal of the experiment is to investigate the size effect on compressive strength and tensile strength as well as the influence of the secondary glued laminated face, which appears in the secondary molding processes. The results show that both compressive strength and tensile strength have the size effect apparently and the existence of the secondary glued laminated face lower the compressive strength of LVL specimens. Afterwards, the relationship between compressive strength and volume along with tensile strength and area are obtained by the test results.

Evaluating Mechanical Properties of Ceramics by Relative Methods

2007 ◽  
Vol 336-338 ◽  
pp. 2406-2410
Author(s):  
Yi Wang Bao ◽  
Xiao Xue Bu ◽  
Yan Chun Zhou ◽  
Li Zhong Liu
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Ceramic Coatings ◽  
Relative Method ◽  
Tempered Glass ◽  
Theoretic Analysis ◽  
Surface Strength ◽  
Indirect Approach ◽  
Before And After ◽  
The Relationship

A relative method, defined as indirect approach to evaluate the material properties via the relationship between unknown properties and a known property, is proposed to estimate some properties that could not be measured by the traditional methods for ceramics. Experiments and theoretic analysis based on the relative method were carried out in this study to estimate the properties in following aspects: determining the temperature dependence of elastic modulus of some machineable ceramics by comparing the deflections; obtaining the modulus and strength of ceramic coatings supported by substrates, from the variation in properties of the rectangular beam samples before and after coating; estimating the residual stresses in tempered glass by comparing the change in the surface strength after strengthening.

Mechanical Nanocrystallization Surface Treatment on the Reheated 400MPa Ultrafine Grained Steel

2009 ◽  
Vol 79-82 ◽  
pp. 377-380
Author(s):  
Hong Yun Zhao ◽  
Guo Dong Wang ◽  
Chun Hua Xu ◽  
Feng Yuan Shu
Keyword(s):  
Mechanical Properties ◽  
Surface Treatment ◽  
Room Temperature ◽  
Performance Testing ◽  
Surface Form ◽  
Test Results ◽  
Ultrafine Grained ◽  
Before And After ◽  
Different Temperatures ◽  
Ultrafine Grained Steel

After reheated at different temperatures for 5 minutes, the 400MPa Ultrafine Grained Steel specimens were air-cooled to room temperature, and then carried out the mechanical nanocrystallization surface treatment and structure performance testing. On the basis of comparing the test results on the specimens before and after the mechanical nanocrystallization surface treatment, the process of mechanical nanocrystallization was analyzed briefly. The results show that: as the reheating temperature rising, the trend of grain size growing increases markedly, and the mechanical properties also drop down to different degrees; when the reheating temperature is around 800°C, because of the pearlite spheroidized significantly, its mechanical properties drop the most seriously; after the mechanical nanocrystallization surface treatment, not only its surface form a layer of fine nano-layer (about 100 nm) structure, but also its mechanical properties rise obviously, and the yield strength is over 450MPa.

Mechanical Properties of Bulk Nanocrystalline Silver-Using Compression Tests

2010 ◽  
Vol 152-153 ◽  
pp. 1313-1316
Author(s):  
Guo Jun Hu ◽  
Zhi Quan Hong
Keyword(s):  
Mechanical Properties ◽  
Coarse Grained ◽  
Strain Rates ◽  
Test Results ◽  
Compression Tests ◽  
Static Test ◽  
Rate Dependent ◽  
Average Grain Size ◽  
Bulk Nanocrystalline ◽  
The Relationship

In this paper, the compression test on the bulk nanocrystalline sliver ( n Ag) with average grain size of 50 nm was made. The stress-strain curves under different strain rates were obtained by test. The test results show that the mechanical behavior of n Ag is rate-dependent, and the dynamic compress yield stress are about 1.5 times of that n Ag in static test condition; The effect of strain harding on n Ag is smaller than that of coarse-grained silver (c Ag) in plastic deformation; The relationship between the yield strength and the logarithm of strain rate is approximately linear.

A Quantitative Evaluation of the Quality of Recycled Steel in Uganda

2012 ◽  
Author(s):  
C. Senfuka ◽  
J. B. Kirabira ◽  
J. K. Byaruhanga
Keyword(s):  
Mechanical Properties ◽  
Raw Material ◽  
Emission Spectrometry ◽  
Test Results ◽  
Geometrical Properties ◽  
Direct Reduced Iron ◽  
The Relationship ◽  
Recycled Steel ◽  
Made In

All steel made in Uganda is currently manufactured from scrap. Such steel has often been characterized by unpredictable performance in consonance with its inconsistent raw material inputs. This study evaluates and relates the mechanical, metallurgical and geometrical properties of these bars in order to identify the factors underlying the performance of the products from this steel and examine the relationship with their scrap content. In order to study the steels, tensile, torsion and micrographic tests have been carried out together with spark emission spectrometry on samples collected from different plants. The test results generally indicate impressive steel resilience, strength and metallographic properties in spite of relatively high and irregular carbon content. Limited weldability, uniaxiality of properties, uneven scatter of microelements and substantial non-uniformity of longitudinal mechanical properties have been observed. Rolling and post rolling defects have been noted. The geometric reliability of the bars has also been found generally low. Improvement of secondary refinement, use of direct reduced iron (DRI) diluent and more diligent sorting have suggested as solutions.

scholarly journals PENGARUH PENAMBAHAN PELEPAH KELAPA SAWIT SEBAGAI BAHAN CAMPURAN TERHADAP SIFAT MEKANIK KUAT TEKAN DAN POROSITAS BATU BATA

2019 ◽  
Vol 1 (2) ◽  
pp. 47-53
Author(s):  
Seno Aji ◽  
Teguh Satria Mahlindo ◽  
Sari Anggraini
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Oil Palm ◽  
Block Design ◽  
Test Results ◽  
Oil Palm Fronds ◽  
Randomized Block Design ◽  
Strength Tests ◽  
Palm Fronds ◽  
Palm Frond

This study aimed to determine the effect of oil palm fronds addition as a mixture to the mechanical properties of bricks in terms of porosity testing, and compressive strength, and to determine the proper percentage of oil palm frond additions. This research is a type of experiment with a randomized block design (RBD) arranged non-factorial and the data is processed using the SPSS 20 Tukey test program. This study used a brick-shaped sample with a length of 19 cm, a width of 9.5 cm and a height of 4.5 cm. Variations in the composition of the added oil palm fronds are 0%, 5%, 10%, 15%, and 20%. Parameter mechanical properties of bricks included porosity, and compressive strength tests. The addition of oil palm fronds with a composition percentage of 0% to 10% affected the mechanical properties of the bricks by reducing porosity and increasing the compressive strength of the bricks. Based on the test results obtained by each of the best test values, namely the minimum porosity value achieved in the percentage of oil palm fronds as much as 10%, which is 18.4%. The optimum compressive strength value is achieved on the percentage of oil palm fronds as much as 10% which is equal to 20.5 N / mm².

scholarly journals The Effect of Cooling Rate on Mechanical Properties of Carbon Steel (St 35)

2014 ◽  
Vol 7 (1) ◽  
pp. 109-118
Author(s):  
Jenan Mohammed Nagie
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Carbon Steel ◽  
Cooling Rate ◽  
Experimental Results ◽  
Heat Treated ◽  
Before And After ◽  
Water Media ◽  
The Relationship

This paper is aimed to study the effect of cooling rate on mechanical properties of Steel 35. Specimens prepared to apply tensile, torsion, impact and hardness tests.Many prepared specimens heat treated at (850ºC) for one hour and subsequently were cooled by three different media [Water-Air-furnace] to show the effect of Medias cooling rate on mechanical properties. Microstructures of all specimens examined before and after heat treatment by an optical microscopy.To figure the phases obtained after heat treatment and its effect on the mechanical properties Experimental results have shown that the microstructure of steel can be changed and significantly improved by varying line cooling rate thus, improving one property will effect on the others because of the relationship between all properties.In water media tensile, torsion and hardness improved while impact results reduced. Air media contributed in improving most of the mechanical properties because of grain size homogeneity. At furnace media ductility and impact improved

Relationship Between Fatigue and Changes in Swim Technique During an Exhaustive Swim Exercise

2016 ◽  
Vol 11 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Natália M. Bassan ◽  
Tadeu E.A.S. César ◽  
Benedito S. Denadai ◽  
Camila C. Greco
Keyword(s):  
Peak Torque ◽  
Stroke Rate ◽  
Elbow Flexors ◽  
Front Crawl ◽  
Stroke Length ◽  
Swim Test ◽  
Strength Tests ◽  
Before And After ◽  
Arm Muscles ◽  
The Relationship

Purpose:To analyze the relationship between the responses of isometric peak torque (IPT) and maximal rate of force development (RFDmax) with the changes in stroking parameters in an exhaustive exercise performed in front crawl.Methods:Fifteen male swimmers performed, on different days, the following protocols: maximal 400-m trial, strength tests before and after an exhaustive test at 100% of the mean speed obtained during the 400-m test, and the same procedures on day 2.Results:The IPT of elbow flexors (79.9 ± 19.4 and 66.7 ± 20.0 N·m) and elbow extensors (95.1 ± 28.0 N·m and 85.8 ± 30.5 N·m) was decreased after the swim test, as was RFDmax (521.8 ± 198.6 and 426.0 ± 229.9 N·m/s; 420.6 ± 168.2 and 384.0 ± 143.5 N·m/s, respectively). Stroke length decreased during the swim test (1.96 ± 0.22 and 1.68 ± 0.29 m/stroke), while stroke rate increased (37.2 ± 3.14 and 41.3 ± 4.32 strokes/min). The propulsive phases increased while the nonpropulsive phases decreased during the test. Significant correlation was found between the changes in IPT and stroke length, stroke rate and recovery (elbow flexors), and entry and catch phase (elbow extensors). In addition, significant correlation was found between the changes in RFDmax of elbow flexors with the changes in pull and recovery phases.Conclusion:Changes in swim technique during an exhaustive test can be, at least in part, associated with fatigue of the arm muscles.

Effect of Hydroentanglement on Structures and Properties of Wet-Laid Paper Sheets

2019 ◽  
Vol 821 ◽  
pp. 201-205
Author(s):  
Chao Deng ◽  
Xian Gyu Jin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Air Permeability ◽  
Water Absorbency ◽  
Structures And Properties ◽  
Before And After ◽  
Properties Of Materials ◽  
Scanning Electron

In this work, pulp/lyocell wet-laid paper sheets have been consolidated by hydroentanglement techniques. Scanning electron microscopy has been used to evaluate the structures of wet-laid paper sheets before and after hydroentanglement. Wet tensile strength along longitudinal (preferential) and transverse directions show the effect of hydroentanglement techniques on the mechanical properties of wet-laid paper sheets. In addition, the air permeability and water absorbency properties of materials have been evaluated. The results show that the structures of wet-laid paper sheets become fluffy and fiber entanglements increase after consolidation. The wet tensile strength values of wet-laid paper sheets at the longitudinal and transverse directions are increased by 109.0% and 78.7%, respectively after hydroentanglement. The air permeability and water absorbency of wet-laid paper sheets are increased by 957.6% and 137.0%.

scholarly journals Polypropylene/ZnO Nanocomposites: Mechanical Properties, Photocatalytic Dye Degradation, and Antibacterial Property

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 914 ◽  
Author(s):  
Ampawan Prasert ◽  
Somchoke Sontikaew ◽  
Dilok Sriprapai ◽  
Surawut Chuangchote
Keyword(s):  
Mechanical Properties ◽  
Zno Nanoparticles ◽  
Dye Degradation ◽  
Antibacterial Properties ◽  
Sunlight Exposure ◽  
Zno Nanoparticle ◽  
Chemical Structures ◽  
Time Period ◽  
Before And After ◽  
Twin Screw

Nanocomposite materials were prepared by compounding polypropylene (PP) with zinc oxide (ZnO) nanoparticles, using a twin-screw extruder. The compound was molded by injection molding to form dumbbell-shaped specimens. The influence of ZnO nanoparticle content on the morphology, mechanical properties, chemical structure, photocatalytic activity, and antibacterial properties of the obtained nanocomposites was investigated. The morphological images showed that the ZnO nanoparticles were well distributed in the PP matrix. Characterizations of the mechanical properties and chemical structures before and after sunlight exposure found that at the shortest exposure time, crosslinks could occur in the nanocomposites, which resulted in improved mechanical properties. However, sunlight exposure with the time period longer than 18 weeks caused the reduction of the mechanical properties, due to degradation of the PP matrix. It was found that PP with 2% ZnO could achieve the photocatalytic degradation of methylene blue up to 59%. Moreover, the result of antibacterial tests indicated that the nanocomposites had better antibacterial properties than neat PP.

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