scholarly journals Breakdown Properties of Cables with Different Inorganic, Insulating Nanomaterials

Inorganics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 90
Author(s):  
Yujia Cheng ◽  
Guang Yu ◽  
Zhuohua Duan

The insulation performance of cable insulating materials can be optimised via matrix modification. Typically, low-density polyethylene (LDPE) is used as the matrix, and a certain proportion of nanoparticles are added to this matrix. To explore the effects of nanoparticles with different forms on the structural interface and crystal morphology of the material, nano-MMT and nano-ZnO were added to LDPE, and comparative experiments were carried out. Based on microscopic test results, material insulation performance changes before and after optimisation were observed. Then, simulation cable models with different insulating materials were developed. Based on the simulated electrical measurements, the thermal breakdown performance of the different insulating materials was tested. According to infrared stereo vision detection results, anomalous temperature points in the cables can be located accurately. Finally, based on macroscopic test results, we verified whether the inorganic, insulating nanomaterials meet the requirements for high-voltage transmission.

Author(s):  
R.A. Herring

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.


1994 ◽  
Vol 71 (04) ◽  
pp. 499-506 ◽  
Author(s):  
Mark W C Hatton ◽  
Bonnie Ross-Ouellet

SummaryThe behavior of 125I-labeled recombinant hirudin towards the uninjured and de-endothelialized rabbit aorta wall has been studied in vitro and in vivo to determine its usefulness as an indicator of thrombin activity associated with the aorta wall. Thrombin adsorbed to either sulfopropyl-Sephadex or heparin-Sepharose bound >95% of 125I-r-hirudin and the complex remained bound to the matrix. Binding of 125I-r-hirudin to the exposed aorta subendothelium (intima-media) in vitro was increased substantially if the tissue was pre-treated with thrombin; the quantity of l25I-r-hirudin bound to the de-endothelialized intima-media (i.e. balloon-injured in vitro) correlated positively with the quantity of bound 131I-thrombin (p <0.01). Aortas balloon-injured in vivo were measured for thrombin release from, and binding of 125I-r-hirudin to, the de-endothelialized intimal surface in vitro; 125I-r-hirudin binding correlated with the amount of active thrombin released (p <0.001). Uptake of 125I-r-hirudin by the aorta wall in vivo was proportional to the uptake of 131I-fibrinogen (as an indicator of thrombin activity) before and after balloon injury. After 30 min in the circulation, specific 125I-r-hirudin binding to the uninjured and de-endo- thelialized (at 1.5 h after injury) aorta wall was equivalent to 3.4 (± 2.5) and 25.6 (±18.1) fmol of thrombin/cm2 of intima-media, respectively. Possibly, only hirudin-accessible, glycosaminoglycan-bound thrombin is measured in this way.


2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK

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


2017 ◽  
Vol 10 (2) ◽  
pp. 94
Author(s):  
Ji Meng

This research investigated a comparison between the effect of cooperative learning and lecture teaching on Comprehensive English classes in a Chinese Independent College. An empirical study for two semesters was carried out in the forms of pretest, posttest, questionnaire and interviews. While control class was taught in the conventional way, experiment class was instructed based on cooperative base groups with positive interdependence structured on purpose. Compared with traditional instructions, cooperative learning as pedagogy can improve students’ performance on course exams, but not necessarily their language competence as shown in national English competency tests taken before and after the experiement. Test results also indicate students from experiment class who excelled in competency test outnumbered those from control class, revealing that cooperative learning has positive impacts especially on students at a relatively higher academic level. Questionaire results show that students are most inclined to agree they have more chances to practice the language in a cooperative environment.


2011 ◽  
Vol 312-315 ◽  
pp. 583-588 ◽  
Author(s):  
Grzegorz Moskal ◽  
Lucjan Swadźba ◽  
Marek Hetmańczyk ◽  
Bartosz Witala

The paper presents test results and characterizes the structural stability of powders, which form a mixture of aluminium oxide (Al2O3) and gadolinium, based on rare earth zirconates. This mixture is provided to create thermal barrier coatings (TBCs) by spraying. The purpose of the tests was to determine the influence of temperature on reactions, occurring between those powders within a temperature range from 25°C to 1500°C, while such conditions were to simulate the conditions, which occur during creation of TBCs and they give an answer to the question concerning mutual reactivity of the powders. The requirements for new materials, provided to spray the TBCs, indicate the necessity to prepare the materials, which do not show tendency towards reactions with the Al2O3, formed during oxidation of Ni (Co) CrAlY, while this reaction is of type bond coat. The tests included differential scanning calorimetric (DSC) analysis and differential thermal analysis (DTA) of powder mixtures. Diffraction analysis was also performed before and after the tests have been finished. The DSC analysis results, obtained at a range of high temperature, did not show any thermal effects, which indicate a low level of mutual reactivity of the powders. However, the DTA analysis suggests presence of such effects at temperature close to 1300°C, and it indicates the necessity to verify exactly the obtained results. Results of the XRD measurement showed that after annealing process already at 1100°C the perovskite oxide of GdAlO3 was present.


2009 ◽  
Vol 297 (5) ◽  
pp. R1312-R1321 ◽  
Author(s):  
Gurjit Nagra ◽  
Lena Koh ◽  
Isabelle Aubert ◽  
Minhui Kim ◽  
Miles Johnston

In some tissues, the injection of antibodies to the β1-integrins leads to a reduction in interstitial fluid pressure, indicating an active role for the extracellular matrix in tissue pressure regulation. If perturbations of the matrix occur in the periventricular area of the brain, a comparable lowering of interstitial pressures may induce transparenchymal pressure gradients favoring ventricular expansion. To examine this concept, we measured periventricular (parenchymal) and ventricular pressures with a servo-null micropipette system (2-μm tip) in adult Wistar rats before and after anti-integrin antibodies or IgG/IgM isotype controls were injected into a lateral ventricle. In a second group, the animals were kept for 2 wk after similar injections and after euthanization, the brains were removed and assessed for hydrocephalus. In experiments in which antibodies to β1-integrins ( n = 10) but not isotype control IgG/IgM ( n = 7) were injected, we observed a decline in periventricular pressures relative to the preinjection values. Under similar circumstances, ventricular pressures were elevated ( n = 10) and were significantly greater than those in the periventricular interstitium. We estimated ventricular to periventricular pressure gradients of up to 4.3 cmH2O. In the chronic preparations, we observed enlarged ventricles in many of the animals that received injections of anti-integrin antibodies (21 of 29 animals; 72%) but not in any animal receiving the isotype controls. We conclude that modulation/disruption of β1-integrin-matrix interactions in the brain generates pressure gradients favoring ventricular expansion, suggesting a novel mechanism for hydrocephalus development.


2008 ◽  
Vol 35 (5) ◽  
pp. 454-460 ◽  
Author(s):  
Krzysztof Zieliński

This article describes the effect of heat aging and styrene–butadiene–styrene (SBS) content in bitumen on the adhesion properties of mastics (bitumen-filler mix) to concrete and steel substrates. Test results showed that the adhesion strength of bituminous mastics to concrete and steel substrates decreased as the SBS content increased. Bitumen types modified with 9%–12% of SBS, commonly used in waterproofing materials, showed an approximately three times weaker bond with concrete and steel substrates than the nonmodified equivalents. Results also showed that after heat aging, the adhesion strength of the nonmodified bitumen was always higher than that of the unheated bitumen modified with 9%–12% of SBS.


2021 ◽  
pp. 21-24
Author(s):  
Neha Sharma ◽  
Ayush Anand ◽  
Shreyas Joshi ◽  
Samrat Ray

BACKGROUND: India, with the declaration of COVID-19 as a pandemic, started imposing restrictions in the country th and initiated a nationwide lockdown under Section 6 of the Disaster Management Act, 2005 on 24 March 2020, followed by four phases of lockdown and then gradual unlock of the country. The rationale behind the same was to avoid social contact. Alcohol dispensing was also stopped during this time and was among the rst services to be reopened by the States. We propose in this paper that this lifting of ban on alcohol sale during the pandemic has led to a signicant increase in the number of COVID-19 cases in the country. METHODS: This is a prospective, observational study, done by collecting data from the Aargya Setu App, which is a mobile application launched by the Ministry of Health and Family Welfare on 2 April 2020 for contact tracing and elf assessment of COVID-19. The data of cumulative number of cases in 12 selected states of the country were compared before and after the lift of ban of alcohol and signicance was shown by the paired t test. RESULTS: The number of COVID-19 positive cases in the country during nationwide lockdown with simultaneous ban on alcohol sale when compared to cumulative number of cases after the lift of ban of alcohol sale during Lockdown and initial Unlock is statistically signicant (p = 0.04) CONCLUSION: We found that the decision to restart the sale of Alcohol could have been a factor for rise in number of cases in the country in the given timeframe. The decision to start the sale has also not been in accordance with the Indian Constitution and against the nation's founding ethics.


2018 ◽  
pp. 1870
Author(s):  
Ika Putri Adnyani ◽  
Gayatri Gayatri

This research is conducted on all acquisition companies that conduct acquisitions listed on Indonesia Stock Exchange 2011-2016 period. Sampling method using purposive sampling. The number of samples of this research is 50 companies. The market reaction in this study used abnormal return and trading volume activity. The testing of information content will be done by looking at differences in cumulative abnormal return and the average trading volume of shares five days before and five days after the announcement of the acquisition. Data analysis technique used is paired sample t-test. Based on the test results, found there are significant differences in the abnormal return of the acquirer company before and after the announcement of the acquisition. However, there is no difference in trading volume activity of the acquirer's stock before and after the acquisition announcement   Keywords: acquisitions, stock market, abnormal return, trading volume activity


Author(s):  
Enea Mustafaraj ◽  
Yavuz Yardim

In this paper, it is presented the experimental results of a campaign on diagonal compression tests, as of ASTM E519-02, to assess and compare the in-plane behavior of standard size of 1200 × 1200 × 250 mm, for three unreinforced and three reinforced wall panels by glass fiber reinforced polymer (GFRP) embedded in an inorganic matrix.From the diagonal compression test results, were determined some of the main mechanical parameters such as: shear strength, modulus of rigidity and ductility, before and after application of the reinforcement.The experimental results showed that the GFRP reinforced panels exhibited a significant increase of 127% in shear resistance, 1100% in ductility and 650% in modulus of rigidity when compared to unreinforced panels.It was concluded that this technique provided satisfactory results and can be considered a suitable method for repair of masonry structures.


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