The influence of V addition on the structure, mechanical properties, and oxidation behaviour of TiAlSiN coatings deposited by DC magnetron sputtering

The influence of V content on the morphology, structure, hardness (H) and reduced Young's modulus (E), adhesion, and oxidation resistance of TiAlSiN coatings is investigated. The coatings were produced by DC reactive magnetron sputtering, with increasing V contents from 0, 4.8 and 11.0 at.%. All coatings exhibit a fcc type structure. The coating with 4.8 at.% of V shows the highest values of H and E, whereas the values are similar for the reference coating and the coating with 11.0 at.% of V. The coatings adhere well to the substrates and show a dense and compact columnar growth extending from the adhesive interlayer to the top surface of the coatings. The dynamic thermal gravimetric oxidation curves reveal that V additions decreases the onset point of oxidation significantly and degrades the oxidation resistance of the coatings. A dual oxide layer is formed on the top surface of the reference coating: an outer porous Ti–Al–O rich layer with plate-like features on the top, which classified to TiO2 (rutile and anatase) and Al2O3 phases, and an inner Ti–Si–O rich layer with Al depletion that identified as mixture of amorphous Si–O and Ti–Si–O protective oxides. The diffusion of V to the top surface governs the oxidation process of the V-containing coatings, i.e. increasing V concentration leads to disrupt the formation of the protective continuous oxide layers easily.This research is sponsored by national funds through FCT e Fundação para a Ciência e a Tecnologia, under the projects: UIDB/00285/2020, SMARTLUBdref. “POCI-01-0145-FEDER-031-807”. MCTool21 project “Manufacturing of cutting tools for the 21st century: from nano-scale material design to numerical process simulation” (reference: POCI-01-0247-FEDER-045940), co-financed by the European Regional Development Fund, through Portugal 2020 (PT2020), and by the Competitiveness and Internationalization Operational Programme (COMPETE 2020).info:eu-repo/semantics/publishedVersio

January reversal in the US weekend effect;

Average returns for small firm size portfolios tend to decrease during the week in January, with Monday returns highest and Friday lowest. More striking are the results after controlling for Mondays and Fridays in the first and the last 3 weeks of January. Monday returns in this first week are significantly positive and inversely related to size. Monday returns are also significantly positive for the small firm size portfolio in the last 3 weeks of January. But returns on Friday are insignificantly different from zero after controlling for Fridays in the first week and the last three weeks of January. The first Monday in January is particularly critical to the reversal of the end-of-the-week effect at the turn-of-the-year, with abnormal demand for stocks following the first weekend of a new calendar year possibly responsible for this anomaly within an anomaly

Multi-layer solar selective absorber coatings based on W/WSiAlNx /WSiAlOyNx/SiAlOx for high temperature applications

A simulated and an experimental design of multilayer solar selective absorber coatings for high temperature applications is presented in this study. The optical tandem is composed of four layers deposited by magnetron sputtering on stainless steel substrates at room temperature. The first is a back-reflector tungsten layer, that is followed by two absorption layers based on WSiAlNx/ WSiAlOyNx structure for phase interference. The final layer is an antireflection layer of SiAlOx. The design was conducted with the help of SCOUT software creating a multilayer model based on transmittance (T) and reflectance (R) spectra of individual thin layers deposited on glass substrates. The final design shows simultaneously high solar absorptance α=96.0% and low emissivity ε=10.5% (calculated at 400 °C) together with high thermal stability at 450 °C, in air, and 600 °C in vacuum for 400 h and 300 h, respectively.FCT -Fuel Cell Technologies Program(PTDC/CTM-ENE/2882/2014)info:eu-repo/semantics/publishedVersio

January reversal in the US weekend effect;

Average returns for small firm size portfolios tend to decrease during the week in January, with Monday returns highest and Friday lowest. More striking are the results after controlling for Mondays and Fridays in the first and the last 3 weeks of January. Monday returns in this first week are significantly positive and inversely related to size. Monday returns are also significantly positive for the small firm size portfolio in the last 3 weeks of January. But returns on Friday are insignificantly different from zero after controlling for Fridays in the first week and the last three weeks of January. The first Monday in January is particularly critical to the reversal of the end-of-the-week effect at the turn-of-the-year, with abnormal demand for stocks following the first weekend of a new calendar year possibly responsible for this anomaly within an anomaly

W/AlSiTiNx/SiAlTiOyNx/SiAlOx multilayered solar thermal selective absorber coating

Solar thermal energy has often been used as a renewable green energy source. Here we present a design composed of a highly selective solar thermal absorber coating that has been deposited by DC magnetron sputtering. This will consist of four layers: W/AlSiTiNx/SiAlTiOyNx/SiAlOx. The coating that was utilised revealed an excellent average solar thermal absorbance, (alpha = 95.5%) with very low emittance, (epsilon = 9.6% calculated for 500 degrees C) together with an excellent thermal stability after annealed at 500 degrees C, in air for 350 h, and at 630 degrees C in vacuum for 220 h.FCT in the framework of the Strategic Funding UID/FIS/04650/2013 and the financial support of FCT, POCI and PORL operational programs through the project POCI01-0145-FEDER-016907 (PTDC/CTM-ENE/2892/2014), co-financed by European community fund FEDER

Characterization of magnetron sputtered sub-stoichiometric CrAlSiNx and CrAlSiOyNx coatings

The influence of varying nitrogen and oxygen partial pressures on microstructure, mechanical and optical properties of magnetron sputtered CrAlSiNx and CrAlSiOyNx coatings has been studied. The partial pressure of nitrogen reactive gaswas varied from0.037 Pa to 0.15 Pa for CrAlSiNx films, and the N2/O2 (85%:15%) partial pressure was varied from 0.046 Pa to 0.21 Pa for CrAlSiOyNx layers. Transmittance and reflectance of samples were measured and were modeled to obtain the spectral optical constants, n and k. Chemical state, composition, morphology and microstructure of films were analyzed by XPS, RBS, XRD, Raman Spectroscopy and SEM. Films' hardness was evaluated using nanoindentation method. XRD results revealed that the two samples CrAlSiNx with PN =0.15 Pa and CrAlSiOyNx with PNO = 0.21 Pa are polycrystalline with cubic (fcc-B1) structure. On contrary, all other films prepared with lower reactive gases partial pressures are amorphous. The chemical composition changed with the variation of reactive gases partial pressure, although the Cr: Al: Si composition ratio remained approximately constant, 1.25:1.5:1. All samples showed low hardness, mainly due to lower content of reactive gases and higher content of Si. However, the sample CrAlSiNx with PN = 0.15 Pa has the highest value of 11.1 GPa. Optical constants are seen to be very sensitive to reactive gases partial pressure. The refractive index and extinction coefficient were lower for coatings with higher reactive gases partial pressure. These coatings are good candidates for designing selective solar absorber stacks for different applications.The authors acknowledge the support of FCT in the framework of the Strategic Funding UID/FIS/04650/2013 and the financial support of FCT, FOCI and PORL operational programs through the project POCI-01-0145-FEDER-016907 (PTDC/C11/1-ENE/2882/2014), co-financed by European community fund FEDER.info:eu-repo/semantics/publishedVersio

The effect of length and inclination of carbon fiber reinforced polymer laminates on shear capacity of near-surface mounted retrofitted reinforced concrete beams

© 2021 The Authors. This study undertakes a comprehensive investigation of the shear behavior of reinforced concrete (RC) beams strengthened by near surface mounted (NSM) carbon fiber reinforced polymer (CFRP) laminates. Different strengthening configurations were employed by varying the length and inclination angle of the CFRP laminates. Results indicated that NSM-CFRP strengthening increased the load-carrying capacity, ductility, stiffness, and toughness from 8% to 41%, 9% to 78%, 24% to 159%, and 22% to 254%, respectively. Results also confirmed that as the CFRP laminate length decreases, the efficacy of the strengthening process increases, where the load-carrying capacity, ductility, stiffness, and toughness improved from 8% to 19%, 10% to 21%, 8% to 68%, and 26% to 119%, respectively. Also, the comparative results revealed that specimens strengthened with 45°-inclined CFRP laminates versus those strengthened with vertical laminates had higher load-carrying capacity (2%–10%), ductility (1%–35%), stiffness (24%–40%), and toughness (13%–32%). Two analytical formulations to predict the contribution of the possible distinct NSM-CFRP shear strengthening configurations for the shear resistance of RC beams were considered. Results indicated an agreement between the experimental and the analytical results for both formulas, where the average values for the safety factor, k, urn:x-wiley:14644177:media:suco202100198:suco202100198-math-0001 were 0.80 and 0.73, with corresponding values of standard deviation of 0.195 and 0.125, respectively.Deanship of Research at Jordan University of Science and Technology. Grant Number: 214/2016

CrAlSiN barrier layer to improve the thermal stability of W/CrAlSiNx/ CrAlSiOyNx/SiAlOx solar thermal absorber

The influence of adding CrAlSiN barrier layer between the back-reflector tungsten (W) and stainless-steel substrate on thermal stability has been investigated. In previous work, after the annealing in vacuum at 600 ºC, tungsten diffusion from the back-reflection layer towards the stainless-steel substrate was found. In this study, a barrier layer was added and its influence upon the W diffusion was studied. Several designs of multilayer solar selective absorber for high temperature applications were used to test the thermal and chemical stability and oxidation resistance after vacuum annealing. These samples were characterized by Scanning Electron Microscopy (SEM), Rutherford Backscattering Spectrometry (RBS), X-ray diffraction (XRD), Fourier-transform Infrared Spectroscopy (FTIR) and UV–VIS–NIR spectroscopy. All absorber tandems show good thermal stability after vacuum annealing at 600 ºC and the changes in optical constants solar absorptance (α) and thermal emittance (ε) are negligible. In some cases, small changes in the reflectance curves after the first step of annealing were seen. Some changes were found in the oxide layer, due to the incomplete oxidized Si atoms, as confirmed by FTIR analyses. This cannot justify the increase of NIR reflectance observed in the optical stacks after annealing, which can be due to the phase changes of the back-reflector tungsten layer. All layers of stacks are amorphous, except the tungsten layer, which is polycrystalline and shows a columnar growth. The addition of a CrAlSiNP= 0.11 Pa barrier layer between tungsten and stainless-steel substrate proved to be a good solution to control the diffusion of W atoms towards the substrate, whereas using higher nitrogen partial pressure in the high and the low absorption layers reduce the diffusion of Cr from those layers to surface.The authors acknowledge the support of FCT in the framework of the Strategic Funding UID/FIS/04650/2013 and the financial support of FCT, POCI and PORL operational programs through the project POCI01-0145-FEDER-016907 (PTDC/CTM-ENE/2882/2014), co-financed by European community fund FEDER.info:eu-repo/semantics/publishedVersio

A design of selective solar absorber for high temperature applications

This study presents a design of multilayer solar selective absorber for high temperature applications. The optical stack of this absorber is composed of four layers deposited by magnetron sputtering on stainless steel substrates. The first is a back-reflector tungsten layer, which is followed by two absorption layers based on CrAlSiNx/ CrAlSiOyNx structure for phase interference. The final layer is an antireflection layer of SiAlOx. The design was theoretically modelled with SCOUT software using transmittance and reflectance curves of individual thin layers, which were deposited on glass substrates. The final design shows simultaneously high solar absorbance = 95.2 % and low emissivity ε= 9.8% (at 400 ºC) together with high thermal stability at 400 ºC, in air, and 600 ºC in vacuum for 650 h.The authors acknowledge the support of FCT in the framework of the Strategic Funding UID/FIS/04650/2013 and the financial support of FCT, POCI and PORL operational programs through the project POCI-01-0145- FEDER-016907 (PTDC/CTM-ENE/2882/2014), co-financed by European community fund FEDER.info:eu-repo/semantics/publishedVersio

Factors and issues affecting electronic insurance adoption in an emerging market

This study examines the factors and issues affecting the adoption of electronic insurance (EI) in the Jordanian insurance sector. The methodology of the study is based on convenience sampling, thus, the sample consists of 175 respondents familiar with E-services, with different backgrounds, professions, businesses, income groups, sectors, and regions. Questionnaires were distributed and disseminated electronically using SurveyMonkey. The study employs both descriptive and ANOVA analyses to analyze the responses. The results show that EI promotes sustainability, reduces costs, saves time and holds some operational benefits beneath. The ANOVA results show that the impact of income and age on sustainability, cost-effectiveness, and operational benefits is significant at least at the 5% significance level. Respondents are also aware that EI may involve issues and challenges related to security and privacy, customer-related issues such as lack of knowledge about repositories, and insurer-related issues such as data shifting. The ANOVA results indicate that gender affects customers’ perceptions of EI adoption regarding customer-related issues; its effect is significant at the 5% level of significance. On the other hand, age and income level are important factors that shape respondents’ perceptions of EI in Jordan. Age is only significant for security-related issues, and income level is a deciding factor in insurer-related issues; their effect is strong and highly significant at the 5% and 1% levels, respectively