Search results for: spin center shift

Authors: Chuang-Chang Chang, Keng-Yu Ho, Yu-Jen Hsiao, Hsin-Ni Yang

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Using a sample of detailed ownership data of 1,032 listed commercial bank observations in 30 European countries from 2004 to 2010, we explore what categories of shareholder are more likely to use derivatives and how different types of owners affect the bank value. We find that a shift in equity from bank investors to either non-financial companies or institutional investors have increase incentives to use derivatives. Moreover, we have significant evidence that a shift in equity from bank investors to either family or manager shareholders who attend derivative activities will decrease bank value. However, a shift in equity from bank investors to non-financial companies who use derivative instrument will increase the bank value. Our results are also robustness to address for the potential endogeneity problems.

Keywords: derivative usage, ownership structure, bank value

Procedia PDF Downloads 319

Authors: Amit Tribedi

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Genuine Quantumness present in Quantum Systems is the resource for implementing Quantum Information and Computation Protocols which can outperform the classical counterparts. These Quantumness measures encompass non-local ones known as quantum entanglement (QE) and quantum information theoretic (QIT) ones, e.g. Quantum Discord (QD). In this paper, some well-known measures of QE and QD in some wheel-like frustrated molecular magnetic systems have been studied. One of the systems has already been synthesized using coordination chemistry, and the other is hypothetical, where the dominant interaction is the spin-spin exchange interaction. Exact analytical methods and exact numerical diagonalization methods have been used. Some counter-intuitive non-trivial features, like non-monotonicity of quantum correlations with temperature, persistence of multipartite entanglement over bipartite ones etc. indicated by the behaviour of the correlations and the QIT measures have been found. The measures, being operational ones, can be used to realize the resource of Quantumness in experiments.

Keywords: 0D Magnets, discord, entanglement, frustration

Procedia PDF Downloads 201

Authors: Jayashree Das, V. V. Srinivasu , D. K. Mishra, A. Maity

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Owing to the important potential applications over decades, transition metal (TM: Mn, Fe, Ni, Cu, Cr, V etc.) doped ZnO-based diluted magnetic semiconductors (DMS) always attract research attention for more and newer investigations. One of the interesting aspects of these materials is to study and understand the magnetic property at room temperature properly, which is very crucial to select a material for any related application. In this regard, Electron spin resonance (ESR) study has been proven to be a powerful technique to investigate the spin dynamics of electrons inside the system, which are responsible for the magnetic behaviour of any system. ESR as well as the Raman and Photoluminescence spectroscopy studies are also helpful to study the defects present or created inside the system in the form of oxygen vacancy or cluster instrumental in determining the room temperature ferromagnetic property of transition metal doped ZnO system, which can be controlled through varying dopant concentration, appropriate synthesis technique and sintering of the samples. For our investigation, we synthesised Cu-doped ZnO nanocrystalline samples with composition Zn1-xCux ( 0.005< x < 0.05) by pyrophoric method and sintered at a low temperature of 650 0C. The microwave absorption is studied by the Electron Spin Resonance (ESR) of X-band (9.46 GHz) at room temperature. Systematic analysis of the obtained ESR spectra reveals that all the compositions of Cu-doped ZnO samples exhibit resonance signals of appreciable line widths and g value ~ 2.2, typical characteristic of ferromagnetism in the sample. Raman scattering and the photoluminescence study performed on the samples clearly indicated the presence of pronounced defect related peaks in the respective spectra. Cu doping in ZnO with varying concentration also observed to affect the optical band gap and the respective absorption edges in the UV-Vis spectra. FTIR spectroscopy reveals the Cu doping effect on the stretching bonds of ZnO. To probe into the structural and morphological changes incurred by Cu doping, we have performed XRD, SEM and EDX study, which confirms adequate Cu substitution without any significant impurity phase formation or lattice disorder. With proper explanation, we attempt to correlate the results observed for the structural optical and magnetic behaviour of the Cu-doped ZnO samples. We also claim that our result can be instrumental for appropriate applications of transition metal doped ZnO based DMS in the field of optoelectronics and Spintronics.

Keywords: diluted magnetic semiconductors, electron spin resonance, raman scattering, spintronics.

Procedia PDF Downloads 269

Authors: Kaiwan S. Ismael, Ergun Ercelebi, Majeed Nader

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This paper describes the design and implementation of a hardware setup for online monitoring of 24 refrigerators inside blood bank center using the microcontroller and CAN bus for communications between each node. Due to the security of locations in the blood bank hall and difficulty of monitoring of each refrigerator separately, this work proposes a solution to monitor all the blood bank refrigerators in one location. CAN-bus system is used because it has many applications and advantages, especially for this system due to easy in use, low cost, providing a reduction in wiring, fast to repair and easily expanding the project without a problem.

Keywords: control area network (CAN), monitoring blood bank center, PIC microcontroller, MPLAB IDE

Procedia PDF Downloads 443

Authors: Jui Chen Wu, Ming Yi Hsu

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Background and Purpose: Shift work of nursing staff is inevitable in hospital to provide continuing medical care. However, shift work is considered as a health hazard that may cause physical and psychological problems. Serious workplace fatigue of nursing shift work might impact on family, social and work life, moreover, causes serious reduction of quality of medical care, or even malpractice. This study aims to explore relationships among nursing staff’s shift, workplace fatigue and quality of working life. Method: Structured questionnaires were used in this study to explore relationships among shift work, workplace fatigue and quality of working life in nursing staffs. We recruited 590 nursing staffs in different Community Teaching hospitals in Taiwan. Data analysed by descriptive statistics, single sample t-test, single factor analysis, Pearson correlation coefficient and hierarchical regression, etc. Results: The overall workplace fatigue score is 50.59 points. In further analysis, the score of personal burnout, work-related burnout, over-commitment and client-related burnout are 57.86, 53.83, 45.95 and 44.71. The basic attributes of nursing staff are significantly different from those of workplace fatigue with different ages, licenses, sleeping quality, self-conscious health status, number of care patients of chronic diseases and number of care people in the obstetric ward. The shift variables revealed no significant influence on workplace fatigue during the hierarchical regression analysis. About the analysis on nursing staff’s basic attributes and shift on the quality of working life, descriptive results show that the overall quality of working life of nursing staff is 3.23 points. Comparing the average score of the six aspects, the ranked average score are 3.47 (SD= .43) in interrelationship, 3.40 (SD= .46) in self-actualisation, 3.30 (SD= .40) in self-efficacy, 3.15 (SD= .38) in vocational concept, 3.07 (SD= .37) in work aspects, and 3.02 (SD= .56) in organization aspects. The basic attributes of nursing staff are significantly different from quality of working life in different marriage situations, education level, years of nursing work, occupation area, sleep quality, self-conscious health status and number of care in medical ward. There are significant differences between shift mode and shift rate with the quality of working life. The results of the hierarchical regression analysis reveal that one of the shifts variables 'shift mode' which does affect staff’s quality of working life. The workplace fatigue is negatively correlated with the quality of working life, and the over-commitment in the workplace fatigue is positively related to the vocational concept of the quality of working life. According to the regression analysis of nursing staff’s basic attributes, shift mode, workplace fatigue and quality of working life related shift, the results show that the workplace fatigue has a significant impact on nursing staff’s quality of working life. Conclusion: According to our study, shift work is correlated with workplace fatigue in nursing staffs. This results work as important reference for human resources management in hospitals to establishing a more positive and healthy work arrangement policy.

Keywords: nursing staff, shift, workplace fatigue, quality of working life

Procedia PDF Downloads 248

Authors: P. V. Leksin, A. A. Kamashev, N. N. Garifyanov, I. A. Garifullin, Ya. V. Fominov, J. Schumann, Y. Krupskaya, V. Kataev, O. G. Schmidt, B. Büchner

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We report on experimental evidence for the occurrence of the long range triplet correlations (LRTC) of the superconducting (SC) condensate in the spin-valve heterostructures CoOx/Fe1/Cu/Fe2/Pb. The LRTC generation in this layer sequence is accompanied by a Tc suppression near the orthogonal mutual orientation of the Fe1 and Fe2 layers’ magnetization. This Tc drop reaches its maximum of 60mK at the Fe2 layer thickness dFe2 = 0.6 nm and falls down when dFe2 is increased. The modification of the Fe/Pb interface by using a thin Cu intermediate layer between Fe and Pb layers reduces the SC transition width without preventing the interaction between Pb and Fe2 layers. The dependence of the SSVE magnitude on Fe1 layer thickness dFe1 reveals maximum of the effect when dFe1 and dFe2 are equal and the dFe2 value is minimal. Using the optimal Fe layers thicknesses and the intermediate Cu layer between Pb and Fe2 layer we realized almost full switching from normal to superconducting state due to SSVE.

Keywords: superconductivity, ferromagnetism, heterostructures, proximity effect

Procedia PDF Downloads 383

Authors: Ahmed I. Alutabi, Naghmeh Dezhabad, Sudhakar Ganti

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Data centers have been growing in size and dema nd continuously in the last two decades. Planning for the deployment of resources has been shallow and always resorted to over-provisioning. Data center operators try to maximize the availability of their services by allocating multiple of the needed resources. One resource that has been wasted, with little thought, has been energy. In recent years, programmable resource allocation has paved the way to allow for more efficient and robust data centers. In this work, we examine the predictability of resource usage in a data center environment. We use a number of models that cover a wide spectrum of machine learning categories. Then we establish a framework to guarantee the client service level agreement (SLA). Our results show that using prediction can cut energy loss by up to 55%.

Keywords: machine learning, artificial intelligence, prediction, data center, resource allocation, green computing

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Authors: Marsden Jacques, Dennis Wong

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A weak order is a way to rank n objects where ties are allowed. In this talk, we present a recursive framework to generate Gray codes for weak orders. We then describe a simple algorithm based on the framework that generates 2-Gray codes for weak orders in constant amortized time per string. This framework can easily be modified to generate other Gray codes for weak orders. We provide an example on using the framework to generate the first Shift Gray code for weak orders, also in constant amortized time, where consecutive strings differ by a shift or a symbol change.

Keywords: weak order, Cayley permutation, Gray code, shift Gray code

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Authors: Chak Kwong Lau

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Many buildings in Hong Kong are graced with enchanting works of Chinese calligraphy. An excellent example is Tao Fong Shan Christian Center founded by a Norwegian missionary, Karl Ludvig Reichelt (1877-1952) in 1930. Adorned with many inspiring works of Chinese calligraphy, the center functions as a place for the study of Christianity where people of different religions can meet to have religious discussions and intellectual exchanges. This paper examines the pivotal role played by Chinese calligraphy in creating a significant context for the center to fulfill her visions and missions. The methodology of this research involves stylistic and textual analyses of works of calligraphy, in particular through an examination and interpretation of their extended meanings in terms of architectural symbology and social and cultural contexts. Findings showed that Chinese calligraphy was effectively used as a powerful vehicle for a purposeful development of contextual Christian spirituality in Hong Kong.

Keywords: Chinese calligraphy, Hong Kong architecture, Hong Kong calligraphy, Johannes Prip-Møller, Karl Ludvig Reichelt, Norwegian missionary, Tao Fong Shan Christian Center, traditional Chinese architecture

Procedia PDF Downloads 245

Authors: Niu Shu Fen

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Sleep disturbance is highly prevalent among shift-working nurses. We aimed to evaluate whether aerobic exercise (i.e., walking combined with jogging) improves objective Sleepparameters among female nurses at the end of an 8-week exercise program and 4 weeks after study completion. This single-blinded, parallel design, randomized controlled trial was conducted in the floor classroom of a would-be medical center in northern Taiwan. Sixtyeligible female nurses were randomly assigned to either aerobic exercise (n = 30) or usual care (n = 30) group. The moderate-intensity aerobic exercise program was performed over 5days (60 min per day) a week for 8 weeks after work hours. Objective sleep outcomes including total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency (SE), were retrieved using an Actigraph device. A generalized estimated equation model was used for data analyses. The aerobic exercise group had significant improvements in TST and SE at 4 weeks and 8 weeks compared with baseline evaluation(TST: B = 70.49 and 55.96, both p < 0.001; SE: B = 5.21 and 3.98, p < 0.001 and 0.002).Significant between-group differences were observed in SOL and WASO at 4 weeks but not8 weeks compared with the baseline evaluation (SOL: B = −7.18, p = 0.03; WASO: B =−11.38, p = 0.008). The positive lasting effects for TST were observed only until the 4-week follow-up. To improve sleep quality and quantity, we encourage female nurses to regularly perform moderate-intensity aerobic exercise.

Keywords: sleep quality, aerobic exercise, nurses, shift work

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Authors: Mohammad Saeed Bahramy

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Transition metal dichalcogenides have experienced a resurgence of interest in the past few years owing to their rich properties, ranging from metals and superconductors to strongly spin-orbit-coupled semiconductors and charge-density-wave systems. In all these cases, the transition metal d-electrons mainly determine the ground state properties. This presentation focuses on the chalcogen-derived states. Combining density-functional theory calculations with spin- and angle-resolved photoemission, it is shown that these states generically host a coexistence of type I and type II three-dimensional bulk Dirac fermions as well as ladders of topological surface states and surface resonances. It will be discussed how these naturally arise within a single p-orbital manifold as a general consequence of a trigonal crystal field, and as such can be expected across many compounds. Our finding opens a new route to design topological materials with advanced functionalities.

Keywords: topology, electronic structure, Dirac semimetals, transition metal dichalcogenides

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Authors: Victoria Bila, Iryna Ventskivska, Oleksandra Zahorodnia

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The goal of the study: To study the distribution of patients of the Kiyv Perinatal Center according to the Robson system and compare it with world data. Materials and methods: a comparison of the distribution of patients of Kiyv Perinatal center according to the Robson system for 2 periods - the first quarter of 2019 and 2020. For each group, 3 indicators were analyzed - the share of this group in the overall structure of patients of the Perinatal Center for the reporting period, the frequency of abdominal delivery in this group, as well as the contribution of this group to the total number of abdominal delivery. Obtained data were compared with those of the WHO in the guidelines for the implementation of the Robson system in 2017. Results and its discussion: The distribution of patients of the Perinatal Center into groups in the Robson classification is not much different from that recommended by the author. So, among all women, patients of group 1 dominate; this indicator does not change in dynamics. A slight increase in the share of group 2 (6.7% in 2019 and 9.3% - 2020) was due to an increase in the number of labor induction. At the same time, the number of patients of groups 1 and 2 in the Perinatal Center is greater than in the world population, which is determined by the hospitalization of primiparous women with reproductive losses in the past. The Perinatal Center is distinguished from the world population and the proportion of women of group 5 - it was 5.4%, in the world - 7.6%. The frequency of caesarean section in the Perinatal Center is within limits typical for most countries (20.5-20.8%). Moreover, the dominant groups in the structure of caesarean sections are group 5 (21-23.3%) and group 2 (21.9-22.9%), which are the reserve for reducing the number of abdominal delivery. In group 2, certain results have already been achieved in this matter - the frequency of cesarean section in 2019 here amounted to 67.8%, in the first quarter of 2020 - 51.6%. This happened due to a change in the leading method of induction of labor. Thus, the Robson system is a convenient and affordable tool for assessing the structure of caesarean sections. The analysis showed that, in general, the structure of caesarean sections in the Perinatal Center is close to world data, and the identified deviations have explanations related to the specialization of the Center.

Keywords: cesarian section, Robson system, Kyiv Perinatal Center, labor induction

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Authors: Saeid Mehvari, Yolanda Sanchez-Vicente, Sergio González Sánchez, Khalid Lafdi

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Abstract- Materials with a combination of transparency, electrical conductivity, and flexibility are required in the ‎growing electronic sector. In this research, electrically conductive and flexible films have been prepared. These ‎composite films consist of dispersing micro-copper particles into polyurethane (PU) matrix. Two sets of samples were ‎made using both spin coating technique (sample thickness lower than 30 μm) and materials casting (sample thickness ‎lower than 100 μm). Copper concentrations in the PU matrix varied from 0.5 to 20% by volume. The dispersion of ‎micro-copper particles into polyurethane (PU) matrix were characterised using optical microscope and scanning electron ‎microscope. The electrical conductivity measurement was carried out using home-made multimeter set up under ‎pressures from 1 to 20 kPa through thickness and in plane direction. It seems that samples made by casting were not ‎conductive. However, the sample made by spin coating shows through-thickness conductivity when they are under ‎pressure. The results showed that spin-coated films with higher concentration of 2 vol. % of copper displayed a ‎significant increase in the conductivity value, known as percolation threshold. The maximum conductivity of 7.2 × 10-1 ‎S∙m-1 was reached at concentrations of filler with 20 vol. % at 20kPa. A semi-empirical model with adjustable ‎coefficients was used to fit and predict the electrical behaviour of composites. For the first time, the finite element ‎method based on the representative volume element (FE-RVE) was successfully used to predict their electrical ‎behaviour under applied pressures. ‎

Keywords: electrical conductivity, micro copper, numerical simulation, percolation threshold, polyurethane, RVE model

Procedia PDF Downloads 161

Authors: Ali Raad Hassan

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In this paper, an (irregular) case relating to base circle, root circle, and pressure angle has been discussed and a computer programme has been developed to simulate and plot spur gear tooth profile, including involute and trochoid curves based on the formulation of rack cutter using different values of pressure angle and profile shift factor and it gave the values of all important geometric parameters. The results showed the flexibility of this approach and versatility of the programme to draw many different cases of spur gear teeth of any module, pressure angle, profile shift factor, number of teeth and rack cutter tip radius. The procedure developed can be extended to produce finite element models of heretofore intractable geometrical forms, to exploring fabrication of nonstandard tooth forms also. Finite elements model of these irregular cases have been built using above programme, and modal analysis has been done using ANSYS software, and natural frequencies of these selected cases have been obtained and discussed.

Keywords: involute, trochoid, pressure angle, profile shift factor, natural frequency

Procedia PDF Downloads 244

Authors: Lalith Edirisinghe, Zhihong Jin, A.W. Wijeratne, Hansa Edirisinghe, Lakshmi Ranwala Rashika Mudunkotuwa

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A paradigm shift in container inventory management (CIM) is a long-awaited industry need. Virtual container yard (VCY) is a concept developed in 2013 and its primary objective is to minimize shipping transport cost through implementing container exchange between carriers. Shipping lines always try to maintain lower container idle time and provide higher customer satisfaction. However, it is disappointing to note that carriers turn a blind eye to the escalating cost resulted from the present inefficient CIM mechanism. The cost of empty container management is simply transferred to the importers and exporters as freight adjustments. It also creates an environmental hazard. Therefore, it has now become a problem for the society. Therefore, a paradigm shift may be required as the present CIM system is not working for common interests of human beings as it should be.

Keywords: collaboation, inventory, shipping, virtual container yard

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Authors: S. Boorboor, S. A. H. Feghhi, H. Jafari

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The ionizing radiations cause different kinds of damages in electronic components. MOSFETs, most common transistors in today’s digital and analog circuits, are severely sensitive to TID damage. In this work, the threshold voltage shift of CD4007 device, which is an integrated circuit including P-channel and N-channel MOS transistors, was investigated for low dose gamma irradiation under different gate bias voltages. We used linear extrapolation method to extract threshold voltage from I_D-V_G characteristic curve. The results showed that the threshold voltage shift was approximately 27.5 mV/Gy for N-channel and 3.5 mV/Gy for P-channel transistors at the gate bias of |9 V| after irradiation by Co-60 gamma ray source. Although the sensitivity of the devices under test were strongly dependent to biasing condition and transistor type, the threshold voltage shifted linearly versus accumulated dose in all cases. The overall results show that the application of CD4007 as an electronic buffer in a radiation therapy system is limited by TID damage. However, this integrated circuit can be used as a cheap and sensitive radiation dosimeter for accumulated dose measurement in radiation therapy systems.

Keywords: threshold voltage shift, MOS transistor, linear extrapolation, gamma irradiation

Procedia PDF Downloads 254

Authors: Jyothirmayee Pola

Abstract:

Ideally, a test-driven development (TDD) or agile or any other process should be able to define and implement performance, scalability, and reliability (PSR) of the product with a higher quality of service (QOS) and should have the ability to fix any PSR issues with lesser cost before it hits the production. Most PSR test strategies for new product introduction (NPI) include assumptions about production load requirements but never accurate. NPE (New product Enhancement) include assumptions for new features that are being developed whilst workload distribution for older features can be derived by analyzing production transactions. This paper talks about how to shift left PSR towards design phase of release management process to get better QOS w.r.t PSR for any product under development. It also explains the ROI for future customer onboarding both for Service Oriented Architectures (SOA) and Microservices architectures and how to define PSR requirements.

Keywords: component PSR, performance engineering, performance tuning, reliability, return on investment, scalability, system PSR

Procedia PDF Downloads 40

Authors: Biao Ma, Jikai Liu, Man Chen, Jianpeng Wu, Liyong Wang, Changsong Zheng

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Proposing an appropriate control strategy is an effective and practical way to address the overheat problems of the wet multi-plate clutch in Direct Shift Gearbox under the long-time creeping condition. To do so, the temperature variation of the wet multi-plate clutch is investigated firstly by establishing a thermal resistance model for the gearbox cooling system. To calculate the generated heat flux and predict the clutch temperature precisely, the friction torque model is optimized by introducing an improved friction coefficient, which is related to the pressure, the relative speed and the temperature. After that, the heat transfer model and the reasonable friction torque model are employed by the vehicle powertrain model to construct a comprehensive co-simulation model for the Direct Shift Gearbox (DSG) vehicle. A creeping control strategy is then proposed and, to evaluate the vehicle performance, the safety temperature (250 ℃) is particularly adopted as an important metric. During the creeping process, the temperature of two clutches is always under the safety value (250 ℃), which demonstrates the effectiveness of the proposed control strategy in avoiding the thermal failures of clutches.

Keywords: creeping control strategy, direct shift gearbox, temperature variation, wet clutch

Procedia PDF Downloads 101

Authors: Sh. Sousani, Z. Shadrokh, M. Hofbauerová, J. Kollár, M. Jergel, P. Nádaždy, M. Omastová, E. Majková

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Perovskite quantum dots (PQDs) have the potential to increase the performance of the perovskite solar cell (PSCs). The integration of PQDs into PSCs can extend the absorption range and enhance photon harvesting and device efficiency. In addition, PQDs can stabilize the device structure by passivating surface defects and traps in the perovskite layer and enhance its stability. The integration of PQDs into PSCs is strongly affected by the type of ligands on the surface of PQDs. The ligands affect the charge transport properties of PQDs, as well as the formation of well-defined interfaces and stability of PSCs. In this work, the CsPbBr₃ QDs were synthesized by the conventional hot-injection method using cesium oleate, PbBr₂ and two different ligands, namely oleic acid (OA) oleylamine (OAm) and didodecyldimethylammonium bromide (DDAB). The STEM confirmed regular shape and relatively monodisperse cubic structure with an average size of about 10-14 nm of the prepared CsPbBr₃ QDs. Further, the photoluminescent (PL) properties of the PQDs/perovskite bilayer with the ligand OA, OAm and DDAB were studied. For this purpose, ITO/PQDs as well as ITO/PQDs/MAPI perovskite structures were prepared by spin coating and the effect of the ligand and oxygen plasma treatment was analyzed. The plasma treatment of the PQDs layer could be beneficial for the deposition of the MAPI perovskite layer and the formation of a well-defined PQDs/MAPI interface. The absorption edge in UV-Vis absorption spectra for OA, OAm CsPbBr₃ QDs is placed around 513 nm (the band gap 2.38 eV); for DDAB CsPbBr₃ QDs, it is located at 490 nm (the band gap 2.33 eV). The photoluminescence (PL) spectra of CsPbBr₃ QDs show two peaks located around 514 nm (503 nm) and 718 nm (708 nm) for OA, OAm (DDAB). The peak around 500 nm corresponds to the PL of PQDs, and the peak close to 710 nm belongs to the surface states of PQDs for both types of ligands. These surface states are strongly affected by the O₃ plasma treatment. For PQDs with DDAB ligand, the O₃ exposure (5, 10, 15 s) results in the blue shift of the PQDs peak and a non-monotonous change of the amplitude of the surface states' peak. For OA, OAm ligand, the O₃ exposition did not cause any shift of the PQDs peak, and the intensity of the PL peak related to the surface states is lower by one order of magnitude in comparison with DDAB, being affected by O₃ plasma treatment. The PL results indicate the possibility of tuning the position of the PL maximum by the ligand of the PQDs. Similar behavior of the PQDs layer was observed for the ITO/QDs/MAPI samples, where an additional strong PL peak at 770 nm coming from the perovskite layer was observed; for the sample with PQDs with DDAB ligands, a small blue shift of the perovskite PL maximum was observed independently of the plasma treatment. These results suggest the possibility of affecting the PL maximum position and the surface states of the PQDs by the combination of a suitable ligand and the O₃ plasma treatment.

Keywords: perovskite quantum dots, photoluminescence, O₃ plasma., Perovskite Solar Cells

Procedia PDF Downloads 35

Authors: Sh. Sousani, Z. Shadrokh, M. Hofbauerová, J. Kollár, M. Jergel, P. Nádaždy, M. Omastová, E. Majková

Abstract:

Perovskite quantum dots (PQDs) have the potential to increase the performance of the perovskite solar cells (PSCs). The integration of PQDs into PSCs can extend the absorption range and enhance photon harvesting and device efficiency. In addition, PQDs can stabilize the device structure by passivating surface defects and traps in the perovskite layer and enhance its stability. The integration of PQDs into PSCs is strongly affected by the type of ligands on the surface of PQDs. The ligands affect the charge transport properties of PQDs, as well as the formation of well-defined interfaces and stability of PSCs. In this work, the CsPbBr₃ QDs were synthesized by the conventional hot-injection method using cesium oleate, PbBr₂, and two different ligands, namely oleic acid (OA)@oleylamine (OAm) and didodecyldimethylammonium bromide (DDAB). The STEM confirmed regular shape and relatively monodisperse cubic structure with an average size of about 10-14 nm of the prepared CsPbBr₃ QDs. Further, the photoluminescent (PL) properties of the PQDs/perovskite bilayer with the ligand OA@OAm and DDAB were studied. For this purpose, ITO/PQDs, as well as ITO/PQDs/MAPI perovskite structures, were prepared by spin coating, and the effect of the ligand and oxygen plasma treatment was analysed. The plasma treatment of the PQDs layer could be beneficial for the deposition of the MAPI perovskite layer and the formation of a well-defined PQDs/MAPI interface. The absorption edge in UV-Vis absorption spectra for OA@OAm CsPbBr₃ QDs is placed around 513 nm (the band gap 2.38 eV); for DDAB CsPbBr₃ QDs, it is located at 490 nm (the band gap 2.33 eV). The photoluminescence (PL) spectra of CsPbBr₃ QDs show two peaks located around 514 nm (503 nm) and 718 nm (708 nm) for OA@OAm (DDAB). The peak around 500 nm corresponds to the PL of PQDs, and the peak close to 710 nm belongs to the surface states of PQDs for both types of ligands. These surface states are strongly affected by the O₃ plasma treatment. For PQDs with DDAB ligand, the O₃ exposure (5, 10, 15 s) results in the blue shift of the PQDs peak and a non-monotonous change of the amplitude of the surface states' peak. For OA@OAm ligand, the O₃ exposition did not cause any shift of the PQDs peak, and the intensity of the PL peak related to the surface states is lower by one order of magnitude in comparison with DDAB, being affected by O₃ plasma treatment. The PL results indicate the possibility of tuning the position of the PL maximum by the ligand of the PQDs. Similar behaviour of the PQDs layer was observed for the ITO/QDs/MAPI samples, where an additional strong PL peak at 770 nm coming from the perovskite layer was observed; for the sample with PQDs with DDAB ligands, a small blue shift of the perovskite PL maximum was observed independently of the plasma treatment. These results suggest the possibility of affecting the PL maximum position and the surface states of the PQDs by the combination of a suitable ligand and the O₃ plasma treatment.

Keywords: perovskite quantum dots, photoluminescence, O₃ plasma., perovskite solar cells

Procedia PDF Downloads 39

Authors: Essam Amerian

Abstract:

The aim of this study was to investigate the effects of improving waist-to-hip ratio (WHR) and visceral fat components on the health of shift workers in an offshore petrochemical company. A total of 100 male shift workers participated in the study, with an average age of 40.5 years and an average BMI of 28.2 kg/m². The study employed a randomized controlled trial design, with participants assigned to either an intervention group or a control group. The intervention group received a 12-week program that included dietary counseling, physical activity recommendations, and stress management techniques. The control group received no intervention. The outcomes measured were changes in WHR, visceral fat components, blood pressure, and lipid profile. The results showed that the intervention group had a statistically significant improvement in WHR (p<0.001) and visceral fat components (p<0.001) compared to the control group. Furthermore, there were statistically significant improvements in systolic blood pressure (p=0.015) and total cholesterol (p=0.034) in the intervention group compared to the control group. These findings suggest that implementing a 12-week program that includes dietary counseling, physical activity recommendations, and stress management techniques can effectively improve WHR, visceral fat components, and cardiovascular health among shift workers in an offshore petrochemical company.

Keywords: body composition, waist-hip-ratio, visceral fat, shift worker, work efficiency

Procedia PDF Downloads 52

Authors: N. A. Parvin, E. B. Ferranti, L. A. Chapman, C. A. Pfrang

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This study intends to investigate the effects of the Urban Heat Island on public health in Birmingham. Birmingham is located at the center of the West Midlands and its weather is Highly variable due to geographical factors. Residential developments, road networks and infrastructure often replace open spaces and vegetation. This transformation causes the temperature of urban areas to increase and creates an "island" of higher temperatures in the urban landscape. Extreme heat in the urban area is influencing public health in the UK as well as in the world. Birmingham is a densely built-up area with skyscrapers and congested buildings in the city center, which is a barrier to air circulation. We will investigate the city regarding heat and cold-related human mortality and other impacts. We are using primary and secondary datasets to examine the effect of population shift and land-use change on the UHI in Birmingham. We will also use freely available weather data from the Birmingham Urban Observatory and will incorporate satellite data to determine urban spatial expansion and its effect on the UHI. We have produced a temperature map based on summer datasets of 2020, which has covered 25 weather stations in Birmingham to show the differences between diurnal and nocturnal summer and annual temperature trends. Some impacts of the UHI may be beneficial, such as the lengthening of the plant growing season, but most of them are highly negative. We are looking for various effects of urban heat which is impacting human health and investigating mitigation options.

Keywords: urban heat, public health, climate change

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Authors: Khaidan Hatami, Mehran Nasiri

Abstract:

The aim of following research was the analysis between sport motivation and control center of football players of Iran. All the players employed in Iran’s football league are included in the population of the research. So, 360 players, every level 120 players ( Youth, U-21 and adults ) playing in Guilan, Kurdistan and Kermanshah province having professional football league in first and second level league were randomly and selectively taken and included the population. The current research is of descriptive and solidarity types. Instruments of measurement are three personal questionnaires, sport motivation (SMS) of Politer and partners (1995), control center of Berger (1986) which their valid content were confirmed by experts in sport management field. The internal stability of questions were analyzed by Alfa Cronbach respectively for sport obligation questionnaire (0.82) and control center (0.86) to analysis and evaluate data, Kolmogrouf-Smirnov, Spearman Correlation, Kruskal-Wallis test, Whitney U, Freedman and T-Wilcoxon were used in a meaningful level (P ≤ 0/05). The results showed positive and meaningful relation between control center of football players in youth, U-21 and adults and sport motivation of football players. So, it can be concluded, people with internal control against those with external one have more internal sport motivation and follow the team goals with more mental power. So, it’s recommended to coaches to use sport psychologist in their teams to internalize the people’s needs by scientific method by taking the mental issues and the type of control in people on life events.

Keywords: sport motivation, control center, internal, external football players

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Authors: El Sayed A. Sharara, A. Tsuji, K. Terada

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Call centers have been expanding and they have influence on activation in various markets increasingly. A call center’s work is known as one of the most demanding and stressful jobs. In this paper, we propose the fatigue detection system in order to detect burnout of call center agents in the case of a neck pain and upper back pain. Our proposed system is based on the computer vision technique combined skin color detection with the Viola-Jones object detector. To recognize the gesture of hand poses caused by stress sign, the YCbCr color space is used to detect the skin color region including face and hand poses around the area related to neck ache and upper back pain. A cascade of clarifiers by Viola-Jones is used for face recognition to extract from the skin color region. The detection of hand poses is given by the evaluation of neck pain and upper back pain by using skin color detection and face recognition method. The system performance is evaluated using two groups of dataset created in the laboratory to simulate call center environment. Our call center agent burnout detection system has been implemented by using a web camera and has been processed by MATLAB. From the experimental results, our system achieved 96.3% for upper back pain detection and 94.2% for neck pain detection.

Keywords: call center agents, fatigue, skin color detection, face recognition

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Authors: Khalid Al Saleh, Najlaa AlSayed

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Background: Palliative care is changing from just ‘end of life care’ to care delivered earlier in the disease course. Metanalysis showed that Palliative Performance Scale (PPS) is associated with increased length of survival. The Palliative Care Center (PCC) in Kuwait is the only stand-alone center in Eastern Mediterranean Region with a capacity of 92 beds. We compared clinical characteristics between patients referred from the Specialized Cancer Center and general hospitals in Kuwait to PCC. Method: A cross Sectional survey was conducted since the opening of PCC in January 2011 to June 2013. Patients’ data on demographics, type of the cancer, PPS score and referring hospital were collected and analyzed. Results: Total number of the patients was 142. Mean age was 61.05±14.79 years, 66 patients (47.1%) were males and 74 (52.9%) were females. The most common cancers in males were lung (n=18, 27.3%) followed by head and neck cancers (n=8, 12.1%) and brain tumors (n=7, 10.6%) while in females, the most common cancers were breast cancer (n=12, 16.7%) followed by ovarian cancer (n=10, 13.9%) and Cancer Colon (n=8, 11.1%). Patients with PPS score 30% were 27.9% (n=39), 40% in 40.7% (n=57), and 50% in 17.1% (n=24) respectively. Patients referred from the Specialized Cancer Center had significantly higher portion of patients with PPS score > 30% (73.4%, n=94), compared to patients coming from general hospitals (33.3%, n=4), P value= 0.007. Conclusion: There is significant difference in PPS scores between patients referred from the Specialized Cancer Center compared to patients referred from general hospitals. We encourage that all cancer patients should be treated in Specialized Cancer Centers and earlier involvement of Palliative Care Centers to achieve better survival. Training workshops are needed for health care professionals working in general hospitals to raise awareness about earlier referral of patients to palliative care services.

Keywords: palliative care, kuwait, performance scale differences, pps score, specialized hospitals

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Authors: Nasser Ghassembaglou, Abdullah Bolek, Oktay Yilmaz, Ertan Oznergiz, Hikmet Kocabas, Safak Yilmaz

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High quality air filters production using nanofibers, as a functional material, has frequently been investigated. As it is more environmentally friendly, melting method has been selected to produce nanofibers. Spun-bond production systems consist of extruder, spin-pump, nozzle package and attenuators. Spin-pump makes molten polymer steady, which flows through extruder. Fibers are formed by regular melts passing through nuzzle holes under high pressure. Attenuator prolongs fibers to micron size to be collected on a conveyor. Different designs of attenuator systems have been studied in this research; new analysis have been done on existed designs considering fibers effect on air flow; it was comprehended that, at fibers presence, there is an air flow which agglomerates fibers as a negative effect. So some new representations have been designed and CFD analysis have been done on them. Afterwards, one of these representations selected as the most optimum and effective design which is brought in this paper.

Keywords: attenuator, CFD, nanofiber, spun-bond

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Authors: V. V. Srinivasu, Jayashree Das

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Owing to the industrial and technological importance, transition metal (TM) doped ZnO has been widely chosen for many practical applications in electronics and optoelectronics. Besides, though still a controversial issue, the reported room temperature ferromagnetism in transition metal doped ZnO has added a feather to its excellence and importance in current semiconductor research for prospective application in Spintronics. Anticipating non controversial and improved optical and magnetic properties, we adopted co doping method to synthesise polycrystalline Mn:TM (Fe,Ni) and Mn:RE(Gd,Sm) co doped ZnO samples by solid state sintering route with compositions Zn1-x (Mn:Fe/Ni)xO and Zn1-x(Mn:Gd/Sm)xO and sintered at two different temperatures. The structure, composition and optical changes induced in ZnO due to co doping and sintering were investigated by XRD, FTIR, UV, PL and ESR studies. X-ray peak profile analysis (XPPA) and Williamson-Hall analysis carried out shows changes in the values of stress, strain, FWHM and the crystallite size in both the co doped systems. FTIR spectra also show the effect of both type of co doping on the stretching and bending bonds of ZnO compound. UV-Vis study demonstrates changes in the absorption band edge as well as the significant change in the optical band gap due to exchange interactions inside the system after co doping. PL studies reveal effect of co doping on UV and visible emission bands in the co doped systems at two different sintering temperatures, indicating the existence of defects in the form of oxygen vacancies. While the TM: TM co doped samples of ZnO exhibit ferromagnetism at room temperature, the TM: RE co doped samples show paramagnetic behaviour. The magnetic behaviours observed are supported by results from Electron Spin resonance (ESR) study; which shows sharp resonance peaks with considerable line width (∆H) and g values more than 2. Such values are usually found due to the presence of an internal field inside the system giving rise to the shift of resonance field towards the lower field. The g values in this range are assigned to the unpaired electrons trapped in oxygen vacancies. TM: TM co doped ZnO samples exhibit low field absorption peaks in their ESR spectra, which is a new interesting observation. We emphasize that the interesting observations reported in this paper may be considered for the improved futuristic applications of ZnO based materials.

Keywords: co-doping, electro spin resonance, microwave absorption, spintronics

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Authors: Prandesha Govender, Chris Cloete

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Purpose: The objective of the paper is to develop a tool for the evaluation of the financial risk of a shopping center. Methodology: Important factors that indicate the success of a shopping center were identified from the available literature. Weights were allocated to these factors and a risk rating was calculated for 505 shopping centers in the largest province in South Africa by taking the factor scores, factor weights, and category weights into account. The ratings for ten randomly selected shopping centers were correlated with consumer feedback and standardized against the ECAI (External Credit Assessment Institutions) data for the same centers. The ratings were also mapped to corporates with the same risk rating to provide a better intuitive assessment of the meaning of the inherent risk of each center. Results: The proposed risk tool shows a strong linear correlation with consumer views and can be compared to expert opinions, such as that of fund managers and REITs. Interpretation of the tool was also illustrated by correlating the risk rating of selected shopping centers to the risk rating of reputable and established entities. Conclusions: The proposed Shopping Centre Risk Tool, used in conjunction with financial inputs from the relevant center, should prove useful to an investor when the desirability of investment in or expansion, renovation, or purchase of a shopping center is being considered.

Keywords: risk, shopping centres, risk modelling, investment, rating tool, rating scale

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Authors: Mohammad Imani, JabraeilNasl Seraji, Abolfazl Zakerian

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Background: Reaction time is the amount of time it takes to respond to a stimulus. In fact The time that passes between the introduction of a stimulus and the reaction by the subject to that stimulus. The aim of this interventional study is evaluation of bright light effects on concentration and diffuse attention reaction time, tension, angry, fatigue and alertness among shift workers. There are several incentives that can reduce the reaction time or added. Bright light as one of the environmental factors can reduce reaction time. Material &Method: This cross-sectional descriptive study was conducted in 1391, in 88 subjects (44 Fixed morning worker and 44 shift worker ) In a 24 h time (13-16-19-22-1-4-7-10) in an ordinary light situation after a randomly selected sample size calculation, concentration and diffuse attention test (reaction time) has been done. After intervention and using of bright light (4500lux), again reaction time test was done. After analyzing by ElISA method obtained data were analyzed by statistical software SPSS 19 and using T-test and ANOVA statistical analysis. Results: Between average of reaction time tests in ordinary light exposed to fixed morning workers and bright light exposed to shift worker, with 95% CI, (P>%5) there was no significant relationship. After the intervention and the use of bright light (4500 lux),between average of concentration and diffused attention reaction time tests in ordinary light exposure on the fixed morning workers and bright light exposure shift workers with 95% CI, (P<5%) there was significant relationship. Conclusion: In sometimes of 24 h during ordinary light exposure concentration and diffused attention reaction time has changed in shift workers. After intervention, during bright light (4500lux) exposure as a light shower, focused and diffuse attention reaction time, tension ,angry and fatigue decreased.

Keywords: bright light, reaction time, tension, angry, fatigue, alertness

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Authors: Dae-gun Kim, Hyun-joo Kang

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Purpose: The purpose of this study was to investigate the effects of aging on center of pressure, gait angle and gait time. Methods: 29 healthy female college students(FCS) and 28 elderly women (EW) were recruited to participate in this study. A gait analysis system( Gaitview, Korea) was used to collect the center of pressure in static state and gait angle with gait time in dynamic state. Results: Results of the center of pressure do not have significant differences between two groups. In the gait angle test, the FCS showed 1.56±5.2° on their left while the EW showed 9.76±6.54° on their left. In their right, the FCS showed 2.85±6.47° and the EW showed 10.27±6.97°. In the gait angle test, there was a significant difference in the gait time between the female college students and elderly women. A significant difference was evident in the gait time. The FCS on the left was 0.87±0.1sec while the EW’s was 1.28±0.44sec. The FCS on the right was 0.86±0.09sec and the EW was 1.1±0.21sec. The results of this study revealed that the elderly participants aging musculoskeletal system and subsequent changes in their posture altered gait angle and gait time. Therefore, this widening is due to their need to leave their feet on the ground longer for stability slowing their movement. Conclusions: In conclusion, it is advisable to develop an exercise program for the elderly focusing on stability the prevention of falls.

Keywords: center of pressure, gait angle, gait time, elderly women

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