scholarly journals Influence of reduction conditions of NiO on its mechanical and electrical properties

2016 ◽  
Vol 6 (1) ◽  
pp. 113 ◽  
Author(s):  
Yehor Brodnikovskyi ◽  
Bogdan Vasyliv ◽  
Viktoriya Podhurska ◽  
Mariusz Andrzejczuk ◽  
Nikkia McDonald ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Structural Changes ◽  
Reduction Stage ◽  
Mechanical And Electrical Properties ◽  
Before And After ◽  
Mechanical Durability ◽  
And Performance ◽  
The Impact ◽  
Volume Decrease

<p class="PaperAbstract"><span lang="EN-GB">Yttria stabilized zirconia with a nickel catalyst (Ni-YSZ) is the most developed, widely used cermet anode for manufacturing Solid Oxide Fuel Cells (SOFCs). Its electro-catalytic properties, mechanical durability and performance stability in hydrogen-rich environ­ments makes it the state of the art fuel electrode for SOFCs. During the reduction stage in initial SOFC operation, the virgin anode material, a NiO-YSZ mixture, is reduced to Ni-YSZ. The volume decrease associated with the change from NiO-YSZ to Ni-YSZ creates voids and causes structural changes, which can influence the physical properties of the anode. In this work, the structural, mechanical and electrical properties of NiO samples before and after reduction in pure H<sub>2</sub> and a mixture of 5 vol. % H<sub>2</sub>-Ar were studied. The NiO to Ni phase transformations that occur in the anode under reducing and Reduction-Oxidation (RedOx) cycling conditions and the impact on cell microstruc­ture, strength and electrical conductivity have been examined. Results show that the RedOx treatment of the NiO samples influence on their properties controversially, due to structural transfor­mation (formation of large amount of fine pores) of the reduced Ni. It strengthened the treated samples yielding the highest mechanical strength values of 25.7 MPa, but from another side it is resulting in lowest electrical conductivity value of 1.9×10<sup>5</sup> S m<sup>-1</sup> among all reduced samples. The results of this investigation shows that reduction conditions of NiO is a powerful tool for influence on properties of the anode substrate.</span></p>

Effects of Functionalization MWCNTs on the Mechanical and Electrical Properties of nylon-6 Composites

2013 ◽  
Vol 750-752 ◽  
pp. 127-131 ◽  
Author(s):  
Xiang Dong Zhu ◽  
Qing Jie Jiao ◽  
Chong Guang Zang ◽  
Xian Peng Cao
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Volume Ratio ◽  
Nylon 6 ◽  
Coupling Process ◽  
Mechanical And Electrical Properties ◽  
Multi Walled Carbon Nanotube ◽  
The Matrix ◽  
The Impact ◽  
Coupling Treatment

Chemically coupling functionalization multi-walled carbon nanotube (MWCNTs)/nylon-6 (PA6) composites were prepared. The nanotubes were first treated by a volume ratio of 3:1 mixture of concentrated H2SO4/HNO3, and then the γ-aminopropyl-triethoxysilane (KH-550) was carried onto the surface of MWCNTs. Effect of MWCNTs coupling treatment on the mechanical and electrical properties of the MWCNTs/PA6 composites were investigated. The impact strength, tensile strength and modulus of p-MWCNTs (coupling process)/PA6 composites increase by 115.9%, 27.2% and 167.7%, respectively, compared with those of the pure nylon-6 resin. A significant increase of the electrical conductivity of the p-MWCNTs/PA6 composites with respect to the original-MWCNTs and a-MWCNTs/PA6 composites due to the increased compatibility with the matrix due to the formation of an inter face with stronger interconnections.

Degradation of Great Tit (Parus Major) Song Before And After Foliation: Implications for Vocal Communication in a Deciduous Forest

Behaviour ◽  
2004 ◽  
Vol 141 (8) ◽  
pp. 935-958 ◽  
Author(s):  
Sandra Blumenrath ◽  
Torben Dabelsteen
Keyword(s):  
Information Transfer ◽  
Structural Changes ◽  
Vocal Communication ◽  
Deciduous Forest ◽  
Parus Major ◽  
Great Tit ◽  
Transmission Experiment ◽  
Distance Information ◽  
Before And After ◽  
The Impact

AbstractSongbirds living in temperate forests experience great seasonal changes in habitat acoustics during the part of the breeding season when singing activity is high. These changes, which are brought about by accelerated vegetation growth and leaf burst in spring, affect sound propagation and potentially render vocal communication more difficult as the total number of scattering and absorbing obstacles increases. We investigated this in a sound transmission experiment in which representative great tit (Parus major) songs were broadcast in a typical forest habitat before and after foliation. Speaker and microphone were placed at natural separation distances and in typical sender and receiver positions. For each song note we quantified several aspects of sound degradation and found that they all increased considerably when leaves were present. Before foliation the same amount of degradation would only be obtained by doubling the transmission distance, i.e. foliage shortens the active space of great tit song. This inevitably alters distance information, provided that distance-dependent, structural changes of received songs are used as ranging cues. Moreover, sender and receiver positions within the canopy become unfavourable compared to heights just below the canopy when the aim is to maximise song propagation distances. Altogether, the presence of foliage greatly affects the potential for vocal information transfer in great tits and requires behavioural and/or perceptual adjustment of the communicating individuals to counteract or reduce the impact of foliage on signal degradation.

Equine hindlimb hoof biomechanics: an evaluation of the effect of routine hoof trimming on force and pressure distribution at midstance

2020 ◽  
Vol 16 (4) ◽  
pp. 333-337
Author(s):  
B. Faramarzi ◽  
M. Polniaszek ◽  
F. Dong
Keyword(s):  
Contact Pressure ◽  
Musculoskeletal Injuries ◽  
Medial Aspect ◽  
P Values ◽  
Pressure Plate ◽  
Before And After ◽  
And Performance ◽  
The Impact ◽  
Hindlimb Lameness ◽  
Paired T Test

Proper hoof function is vital for equine health and performance. Many musculoskeletal injuries in horses originate from the foot. Most studies performed to date have focused on the forehoof while the hindhoof (HH) has received less attention. Our goal was to examine the influence of routine hoof trimming on HH medio-lateral hoof balance. The objective of this study was to examine force (F), contact pressure (CP), and contact area (CA) at the medial and lateral aspects of the HH to evaluate the impact of routine hoof trimming on HH biomechanics. Clinically sound Arabian horses (n=9) were walked across a calibrated pressure plate before and after routine hoof trimming and the F, CP, and CA at the medial and lateral aspects of the HH were recorded at midstance pre- and post-trimming. The differences between these regions were investigated using a paired T-test. P-values <0.05 were considered significant. Among measured variables, force increased by 25% (P=0.007) and contact pressure increased by 13% (P=0.032) at the medial aspect of the HH after routine hoof trimming. Analysing data from hindlimb hoof-surface interaction in sound horses will allow for a better understanding of imbalances that may lead to pathologies and hindlimb lameness in horses.

scholarly journals INTELLECTUAL CAPITAL, FINANCIAL CRISIS AND PERFORMANCE OF ISLAMIC BANKS: DOES SHARIAH GOVERNANCE MATTER?

2017 ◽  
Vol 18 (1) ◽  
Author(s):  
Tasawar Nawaz
Keyword(s):  
Financial Crisis ◽  
Intellectual Capital ◽  
Economic Performance ◽  
Islamic Banks ◽  
Knowledge Resources ◽  
Finance Industry ◽  
Before And After ◽  
And Performance ◽  
Shariah Governance ◽  
The Impact

This paper empirically examines the impact of intellectual capital (IC) and Shariah governance on economic performance of 47 Islamic banks (IBs) operating in the Gulf Cooperation Council (GCC) region in pre- and post-financial crisis period. The analysis suggests that higher IC efficiency helps IBs to improve their odds of survival at all times i.e. before- and after-crisis. Further, higher IC efficiency helps IBs to maintain their profitability i.e. ROA and market valuation i.e. Tobin’s Q at all times. Arguably, knowledge-resources i.e. IC is the main line of defence for IBs against negative shocks. Lastly, the study reveals that Shariah governance alone may fall short in explaining the growth trends in Islamic finance industry. Keywords: Intellectual Capital; Shariah Governance; Financial Crisis; Islamic Worldview; Economic Performance.

Os efeitos da aprendizagem da esgrima sobre o controle executivo da memória

2021 ◽  
Author(s):  
Gabriel MenezesPaes Rodrigues ◽  
Nilo Terra Arêas Neto
Keyword(s):  
Executive Control ◽  
Learning Difficulties ◽  
Field Research ◽  
School Failure ◽  
Before And After ◽  
Brazilian Students ◽  
And Performance ◽  
The Impact ◽  
Dependent Samples ◽  
Learning And Performance

Treated as one of the biggest challenges in the Brazilian educational system, school failure, despite being multi-causal, is closely linked to learning difficulties associated with aspects of cognition, with special attention to the Executive Control of Memory, which in this study will be represented by the variables: Working Memory (MT), Concentrated Attention (AC) and Motor Reaction Time (TRM). Under neuropsychological aspects, the executive control of memory comprises closely linked phenomena and mechanisms and learning, such as: cognitive flexibility, decision making, attention mechanisms, inhibitory control, selection and integration of current information with information already memorized, in addition to planning and monitoring their own learning and performance. This form of cognitive ability is defined by renowned researchers in the “field” as being preponderant to human learning and performance. Dysfunctions in the executive control of memory are commonly a reflection of innate or non-innate psychopathological issues, may be associated with other comorbidities, and are determinants of school failure in a significant number of Brazilian students. Thus, the main objective of this research project is to verify the impact of the practice of the fighting modality Fencing on the executive control of the memory of students from the public school system, participants of this action research, included in psychopedagogical care for issues related to learning difficulties cognitive. The Field Research technique will be used in this study, with the process of testing the variables under study in moments before and after the intervention with fencing classes. The data obtained in the testing process will be treated in a descriptive statistical perspective. For the inference of the data obtained, the Student T Test for dependent samples will be used. To verify the distribution of data, the Shapiro-Wilk test will be used. As a result, research participants are expected to obtain statistically significant results in the studied variables.

Mechanical and Electrical Properties of Carbon Nanotube / Polydimethylsiloxane Composites Yarn

2016 ◽  
Vol 11 (4) ◽  
pp. 155892501601100 ◽  
Author(s):  
Wei Liu ◽  
Fujun Xu ◽  
Nianhua Zhu ◽  
Shuang Wang
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Electrical Properties ◽  
Strain Sensors ◽  
Electromechanical Properties ◽  
Average Strength ◽  
Mechanical And Electrical Properties ◽  
Carbon Nano Tube ◽  
Droplet Infiltration

Carbon nano tube (CNT) yarn is an axially aligned CNT assembly. It has great potential many applications. In this study, the mechanical and electrical properties of the aerogel-spun CNT yarns and CNT/Polydimethylsiloxane (PDMS) composite yarns were investigated. The CNT/PDMS yarn was fabricated by droplet infiltration of PDMS solution into the aerogel-spun CNT yarn. The mechanical properties of the CNT/PDMS yarns were significantly improved with an average strength of 837.29 MPa and modulus of 3.66 GPa, over 100% improvement compared to the original CNT yarns. The electrical conductivity of the CNT/PDMS yarn increased from 1636 S/cm to 3555 S/cm. The electromechanical properties of CNT/PDMS yarns demonstrated that such CNT yarn could be suitable for strain sensors.

scholarly journals Theoretical Description of Carbon Felt Electrical Properties Affected by Compression

2019 ◽  
Vol 9 (19) ◽  
pp. 4030 ◽  
Author(s):  
Moshe Averbukh ◽  
Svetlana Lugovskoy
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Close Contact ◽  
Internal Surface ◽  
Theoretical Models ◽  
Theoretical Description ◽  
Carbon Felt ◽  
Long Carbon Fibers ◽  
Carbon Filaments ◽  
The Impact

Electro-conductive carbon felt (CF) material is composed by bonding together different lengths of carbon filaments resulting in a porous structure with a significant internal surface that facilitates enhanced electrochemical reactions. Owing to its excellent electrical properties, CF is found in numerous electrochemical applications, such as electrodes in redox flow batteries, fuel cells, and electrochemical desalination apparatus. CF electro-conductivity mostly arises from the close contact between the surface of two electrodes and the long carbon fibers located between them. Electrical conductivity can be improved by a moderate pressing of the CF between conducting electrodes. There exist large amounts of experimental data regarding CF electro-conductivity. However, there is a lack of analytical theoretical models explaining the CF electrical characteristics and the effects of compression. Moreover, CF electrodes in electrochemical cells are immersed in different electrolytes that affect the interconnections of fibers and their contacts with electrodes, which in turn influence conductivity. In this paper, we investigated both the role of CF compression, as well as the impact of electrolyte characteristics on electro-conductivity. The article presents results of measurements, mathematical analysis of CF electrical properties, and a theoretical analytical explanation of the CF electrical conductivity which was done by a stochastic description of carbon filaments disposition inside a CF frame.

scholarly journals Assessment of the Impact of Stagnation Temperatures in Receiver Prototypes of C-PVT Collectors

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2967 ◽  
Author(s):  
João Gomes
Keyword(s):  
Solar Cells ◽  
Thermal Stress ◽  
Structural Integrity ◽  
Heat Transfer Fluid ◽  
Strain Relief ◽  
Prototype Test ◽  
Before And After ◽  
And Performance ◽  
Initial Power ◽  
The Impact

Concentrating Photovoltaic Thermal (C-PVT) solar collectors produce both thermal and electric power from the same area while concentrating sunlight. This paper studies a C-PVT design where strings of series-connected solar cells are encapsulated with silicone in an aluminium receiver, inside of which the heat transfer fluid flows, and presents an evaluation on structural integrity and performance, after reaching stagnation temperatures. Eight test receivers were made, in which the following properties were varied: Size of the PV cells, type of silicone used to encapsulate the cells, existence of a strain relief between the cells, size of the gap between cells, and type of cell soldering (line or point). The test receivers were placed eight times in an oven for one hour at eight different monitored temperatures. The temperature of the last round was set at 220 °C, which exceeds the highest temperature the panel design reaches. Before and after each round in the oven, the following tests were conducted to the receivers: Electroluminescence (EL) test, IV-curve tracing, diode function, and visual inspection. The test results showed that the receivers made with the transparent silicone and strain relief between cells experienced less microcracks and lower power degradation. No prototype test receiver lost more than 30% of its initial power, despite some receivers displaying a large number of cell cracks. The transparent and more elastic silicone is better at protecting the solar cells from the mechanical stress of thermal expansion than the compared silicone alternative, which was stiffer. As expected, larger cells are more prone to develop microcracks after exposure to thermal stress. Additionally, existing microcracks tend to grow in size relatively fast under thermal stress. EL imaging taken during our experiment leads us to conclude that it is far more likely for existing cracks to expand than for new cracks to appear.

Influence of alcohol on mechanical and electrical properties of thin organic films

Open Physics ◽  
2007 ◽  
Vol 5 (3) ◽  
Author(s):  
Martin Kopáni ◽  
Martin Weis
Keyword(s):  
Electrical Properties ◽  
Conformational Changes ◽  
Structural Changes ◽  
Pure Water ◽  
Contactless Method ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Mechanical And Electrical Properties ◽  
Methanol Solutions ◽  
The Stability ◽  
Displacement Currents

AbstractStability of organic materials properties is essential for further applications and was intensely investigated in last few decades. The aim of this study is to detect the structural changes of dipalmitoyl-phosphatidylcholine (DPPC) monolayer as a model system of organic material under influence of alcohols solutions. As subphases of monolayers (Langmuir films), pure water, ethanol and methanol solutions were used. For detection of changes in charge states of the molecules as well as relation with structural and conformational changes, a contactless method employing Maxwell’s displacement currents (MDC) was used. In DPPC monolayer on the subphase of methanol-water, a gradual absorption of methanol molecules into the layer can appear. In DPPC monolayer on the subphase of ethanol-water adsorption of ethanol molecules on the layer can be observed. Influence of alcohols results in a significant change of mechanical and electrical properties as well as in the stability of thin films.

scholarly journals Effects of caloric restriction on anthropometrical and specific performance in highly-trained university judo athletes

2018 ◽  
Vol 3 (3) ◽  
pp. 105 ◽  
Author(s):  
Lalia CHRARA ◽  
RIAD A.Raoui ◽  
Adel Belkadi ◽  
Hocine ASLI ◽  
Othman BENBERNOU
Keyword(s):  
Weight Loss ◽  
Caloric Restriction ◽  
Body Mass ◽  
Weight Maintenance ◽  
Food Record ◽  
Fitness Test ◽  
Before And After ◽  
Judo Athletes ◽  
And Performance ◽  
The Impact

Purpose:The purpose of this study was to determine the ultimate body mass, performance, and nutritional characteristics of the Algerian judo junior athletes, and also analysing the impact of nutritional intakes on stabilising Weight loss according to special performance of judo athletes. Material:Twenty-one male university athletes (aged: 21.45 ± 1.32; height: 1.81 ± 0.45 m; and body mass: 73.9 ± 4.1 kg) participated in this study during a period of stabilising Weight loss before and after 15 days of caloric restriction. Athletes were submitted to anthropometrical measurements and performed the Special Judo Fitness Test. Values for nutrient intakes were obtained from a 15 day food record kept during a training camp period of Weight maintenance and after a 15-day caloric restriction.Results:caloric restriction resulted in significant decreases in body mass (73.73 ± 2.1) and performance. However, Special Judo Fitness Test index increased significantly (14.00 ± 1.75) during caloric restriction in comparison to stabilising Weight loss.Conclusion:Exercise and caloric restriction lead to determine the ultimate Weight and physical performance. The present study provides baseline nutritional data that can be used in the prescription of individual training programs for university  judo Athletes.

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