Kim Model Research Articles

An 80 Gbps Integrated PDM‐OAM‐Enabled‐FSO Transmission for Implementing 5G Services Under Riyadh Weather Conditions

ABSTRACTThe surge in demand of high‐capacity wireless information transmission links has led to emergence of novel multiplexing techniques for free space optics (FSO) over the past few years. Two such important techniques are polarization division multiplexing (PDM) and orbital angular momentum (OAM) multiplexing. This article investigates the integration of PDM and OAM techniques in a FSO transmission system to enable 5G communication services in Riyadh City, Saudi Arabia. Four OAM beams () of 2‐polarization states of a single frequency laser beam are used to transport 10 Gbps data independently. A total of 80 Gbps net transmission rate is achieved. The visibility data for Riyadh city are collected from Saudi Meteorological Department and the attenuation coefficient is calculated using Kim, Kruse, and Al‐Naboulsi attenuation models. The performance of all the PDM‐OAM modulated signals is compared for the three‐attenuation models in terms of bit error rate, eye diagrams, and Q Factor of the signal at the receiver. The results show that using Kim and Kruse models, with attenuation of 0.62 and 0.64 dB/km, the maximum range of 3.8 km is achieved. This is, however, reduced to 2.4 km using Al‐Naboulsi model having attenuation of 2.03 dB/km with acceptable limits of Q Factor (∼6 dB) and BER (∼9).

On the trapped magnetic moment in type-II superconductors

Abstract Measurements of the trapped (remanent) magnetic moment, M trap ( H ) , when a small magnetic field H is turned off after cooling below the superconducting transition temperature, Tc , or ramping a magnetic field up and down after cooling in a zero magnetic field, offer substantial advantages in difficult cases of small samples and large field-dependent backgrounds, which is relevant for hydrogen-based ultra-high-T c superconductors (UHTS). Until recently, there was no need for a separate paper on the trapped magnetic flux for well-known critical-state models due to the simplicity of the physics involved. However, recent publications showed the need for such an analysis. This note summarizes the expectations for the Bean model with constant critical current density and the Kim model with field-dependent critical currents. It is shown that if the trapped moment is fitted to the power law, M trap ∝ H α , the fixed exponent α = 2 is exact for the Bean model, while Kim models show a wide interval of possible values, 2 ⩽ α ⩽ 4 . Furthermore, accounting for reversible magnetization expands the range of possible exponents to 1 ⩽ α ⩽ 4 . In addition, demagnetizing factors are essential and make the trapped moment orientation dependent even in isotropic materials. As a concrete application, it is shown that flux trapping experiments performed on H3S UHTS compounds can be well described using this generalized approach, lending further support to the type-II superconducting nature of H3S under ultra-high pressure.

Destination Resources and the Growth of Cruise Tourism in Mombasa County, Kenya

Kenya is focused on being a piece of the voyage transport circuit. Towards this end, a first voyage terminal whose development is in progress in Mombasa will be finished inside the 2018 – 2022 period. The overall study goal was to determine the relationship between destination resources and the growth of cruise tourism in Mombasa County, Kenya. Cross sectional survey research design will be used in this study. The location of the study was Mombasa County where cruise tourism has developed roots in Kenya. The study was anchored on Dwyer & Kim model on destination competitiveness and Freeman stakeholder theory. Population of the study consisted of 340 respondents drawn from managers of tourism enterprises and senior managers at Kenya Ports Authority (KPA), Kenya Tourism Board (KTB), Ministry of Tourism and Wildlife, as well as coast tourism and hospitality associations. The gathered information was analysed by use of descriptive statistics; mean, mode, median, standard deviation, tables, figures, rates and frequencies. The SPSS 28 was used to analyze the data. Plausible results of the investigation were that port's inalienable attributes, foundations, and travellers assets are just a portion of the variables deciding journey the travel industry advancement hence significant that the administrative structure that bolsters the improvement of this industry and that neighbourhood open and private organizations cultivate compelling associations with voyage lines and mastermind programs guaranteeing a satisfactory progression of journey vacationers every year. The quantitative findings revealed a significant positive relationship between destination resources and the growth of cruise tourism, supported by a high R Square value of 0.794 and a significant F value of 1099.616 (p < 0.001). In conclusion, the study revealed significant relationships between destination resources and the growth of cruise tourism in Mombasa County. To enhance cruise tourism, stakeholders should focus on optimizing destination resources. Recommendations include continuous infrastructure development, targeted marketing campaigns, and community engagement. The study contributes valuable insights for policymakers, industry players, and researchers to foster sustainable growth in Mombasa's cruise tourism sector. Submitted 19th Jul 2024 Reviewed 29th Sep, 2024 Accepted 5th Oct 2024 Published 20th Oct 2024

An Innovative Approach to Measuring the Tourism Competitiveness of Bosnia and Herzegovina Using the Integrated (Dwyer & Kim) Model

Abstract Competitiveness is a generally accepted concept that emerges in all social and economic spheres, so understanding competitiveness in the sphere of tourism is also essential for destinations to attract a significantly larger number of tourists and increase tourism expenditure. The aim of the research in this paper is related to the verification of the applicability of the Integrated Competitiveness Model, which was created by Larry Dwyer & Lee Kim. In order to demonstrate the applicability of the Integrated Competitiveness Model using the example of Bosnia and Herzegovina, the paper established a clear methodological framework based on a questionnaire as the main research instrument, which was interpreted by applying a Likert scale, and the responses were analyzed using measures of descriptive statistics. The statistical processing of the collected responses indicates the successful applicability of the Integrated Model, according to which Bosnia and Herzegovina is a moderately competitive destination. A particular significance of the model is its precise suggestion of the multidimensionality and interdependence of competitiveness determinants, highlighting those that need improvement. The research, which utilized an innovative approach through a survey questionnaire, achieved representativeness through careful sample selection, encompassing not only tourists but also representatives of the tourism industry, resulting in original conclusions.

A step length estimation method based on frequency domain feature analysis and gait recognition for pedestrian dead reckoning

Purpose Step length is a key factor for pedestrian dead reckoning (PDR), which affects positioning accuracy and reliability. Traditional methods are difficult to handle step length estimation of dynamic gait, which have larger error and are not adapted to real walking. This paper aims to propose a step length estimation method based on frequency domain feature analysis and gait recognition for PDR, which considers the effects of real-time gait. Design/methodology/approach The new step length estimation method transformed the acceleration of pedestrians from time domain to frequency domain, and gait characteristics of pedestrians were obtained and matched with different walking speeds. Findings Many experiments are conducted and compared with Weinberg and Kim models, and the results show that the average errors of the new method were improved by about 2 meters to 5 meters. It also shows that the proposed method has strong stability and device robustness and meets the accuracy requirements of positioning. Originality/value A sliding window strategy used in fast Fourier transform is proposed to implement frequency domain analysis of the acceleration, and a fast adaptive gait recognition mechanism is proposed to identify gait of pedestrians.

Numerical solutions to Hyperbolic Maxwell quasi-variational inequalities in Bean–Kim model for type-II superconductivity

This paper is devoted to the finite element analysis for the Bean–Kim model governed by the full 3D Maxwell equations. Describing type-II superconductivity at the macroscopic level, this model leads to a challenging coupled system consisting of the Faraday equation and a hyperbolic quasi-variational inequality (QVI) of the second kind with L1-type nonlinearity, that arises explicitly from the magnetic field dependency in the critical current. With the involved Maxwell coupling in the 3D H(curl)-setting, the hyperbolic QVI character poses the primary challenge in the numerical investigation. Two mixed finite element methods based on implicit Euler and leapfrog time-stepping are proposed. On the one hand, the implicit Euler method results in a nonstandard system of curl-curl elliptic QVI with a first-order curl-type nonlinearity. Though the well-posedness of this system is guaranteed, its numerical realization is not straightforward and requires the use of a two-stage iteration process of high computational complexity. On the other hand, by approximating the electric and magnetic fields at two different time step levels, the leapfrog method turns out to be more suitable as it naturally eliminates the notorious QVI structure. More importantly, utilizing suited subdifferential and optimization techniques, we are able to prove an efficiently computable explicit formula for its exact solution in terms of the electric field, which makes its numerical computation substantially more favorable than the Euler method. As further advantages, the leapfrog method applies to broad scenarios involving low regular data of bounded variation (BV) in time for both the applied current source and the temperature distribution. Through nonstandard technical arguments tailored to the BV data, our analysis proves the conditional stability and, eventually, the uniform convergence of the proposed leapfrog method. This paper is closed by 3D numerical tests showcasing the reasonable and efficient performance of the proposed numerical solution.

Performance investigation of a liquid immersion cooling system with fish-shaped bionic structure for Lithium-ion battery pack

A battery thermal management system (BTMS) is crucial for the safety and performance of lithium-ion batteries (LIBs) in electric vehicles. To improve the BTMS in terms of cooling performance and pumping cost, an innovative liquid immersion battery cooling system (LIBCS) using flow guides with fish-shaped holes is proposed. The design of this flow guide is grounded in conformal mapping technology and bionics principles. An electrochemical-thermal model for the battery module is established by the Multi-Scale Multi-Domain approach with the Newman, Tiedemann, Gu, and Kim model. The simulation and experimental results show good agreement, with mean absolute errors of 0.0174 V, 0.126 °C, and 0.042 Pa for LIB voltage, maximum temperature, and average pressure drop, respectively. Furthermore, the effects of four different battery pack structures on the performance of LIBCSs under different operating conditions are investigated. For LIBs at a 3C discharge rate, the LIBCS using common flow guides decreases the maximum LIB temperature by 5.3 % at a mass flow rate of 0.00273 kg/s compared to the without flow guide case, but it increases the pump power consumption by 81.4 %. However, using flow guides with circular holes or fish-shaped holes reduces the maximum LIB temperature by 9.2 % and 12.2 %, respectively, compared to LIBCS using common flow guides, while maintaining maximum temperature differences within 5 °C. Interestingly, the LIBCS using flow guides with fish-shaped holes reduces the pump power consumption by 42.1 % and 11.8 %, respectively, compared to the common flow guide and flow guide with circular holes cases under the same operating conditions. Additionally, the comprehensive performance factor of LIBCS using flow guides with fish-shaped holes improves by 24 %, 39.3 % and 7.3 % at a mass flow rate of 0.00273 kg/s, respectively, compared to cases using no flow guide, common flow guides and flow guides with circular holes, indicating greater value for application in practical engineering.

Influence of width-to-depth and effective length-to-depth ratio on shear strength of reinforced concrete slender beams without shear reinforcement: comparative analysis

PurposeFrom the factors that affect shear strength of reinforced concrete (RC) beams, the study examines the effect of controversial parameters, width-to-depth (b/d) and effective length-to-depth (leff/d) ratio on shear strength of RC slender beams.Design/methodology/approachThe researchers utilized a database of 676 experimental test results from ACI-DAfStb database, Conducted regression analysis to examine relationship between b/d and leff/d ratios and shear strength, compare and analyze sensitivity to changes in b/d and leff/d ratios for the selected 12 shear models for RC beams.FindingsIncreasing b/d ratio enhanced shear strength until b/d ˜ 3, but further increases had limited impact and increasing leff/d ratio resulted in decreased shear strength. From comparative analysis, the models provided by various design standards were found to be safe, with EC-2 and JSCE models being conservative. From considered research models, Campione and Arslan models were conservative, while Kim and White model were observed to be unsafe. Sensitivity analysis indicated ACI318-19, JSCE, CEB-FIP-90 and Arslan models were sensitive to changes in b/d and leff/d ratios. National code models generally captured shear strength characteristics well. Certain models suggested a constant/decreasing b/d effect despite observed shear strength enhancement. Most models indicated improved shear strength with an increasing leff/d ratio, contrary to experimental findings while TS500 and Hwang models aligned with experimental results.Research limitations/implicationsThe study's limitations include the dependence on the available database, which may not encompass all possible experimental scenarios. Further research should aim to expand the database and investigate additional parameters that may influence shear strength in RC beams.Practical implicationsThe findings of this study have practical implications for the design and analysis of RC beams by suggesting that the width-to-depth and length-to-depth ratios should be carefully considered to optimize shear strength. The identified models can assist engineers in selecting appropriate shear strength prediction models based on specific design scenarios.Social implicationsThe study contributes to the advancement of knowledge in the field of reinforced concrete beam design, which has implications for the safety and reliability of structural systems. By understanding the factors influencing shear strength, engineers can design more efficient and robust structures, ensuring the safety of buildings and infrastructure.Originality/valueThis study provides valuable insights into the influence of the width-to-depth and effective length-to-depth ratios on shear strength in reinforced concrete beams. It contributes to the understanding of these factors and their impact on shear strength, addressing the lack of consensus among researchers. The comparative analysis of shear models and the sensitivity analyses add value by identifying the models that align better with experimental observations. The study emphasizes the need for accurate models that account for these factors and highlights the importance of further research to refine and develop improved predictive models.

A Concept Analysis of Spiritual Self-Care in Hospice Team Members by Hybrid Model

Purpose: The study aimed to clarify the concept of spiritual self-care in hospice team members. Methods: To analyze the concept of spiritual self-care of hospice care team, the study was carried out using Schwartz-Barcott and Kim's hybrid model including theoretical, fieldwork and final analytic stages. In the theoretical stage, 'spirituality', 'spiritual well-being', 'spiritual health', 'spiritual care', and 'self-care' were set as search terms, and the resulting 107 related works of domestic and international literature were analyzed. In the field survey stage, data were collected from nurses and spiritual experts with more than 5 years of experience in spiritual self-care.Results: The concept of spiritual self-care is to realize the meaning and purpose of life while constantly maintaining relationships with oneself, neighbors, communities, and the absolute, utilize transcendence and internal resources, strengthen professional competence, maintain work-life balance, and achieve spiritual well-being. It was identified as a dynamic state to realize. The quality attributes of the concept of spiritual self-care were found to have 5 attributes and 15 indicators. Conclusion: The attributes and indicators derived through this study will be helpful in understanding the concept of hospice team members' spiritual self-care. In addition, as a way to continuously grow and train professional hospice team members, it can be used to develop a spiritual self-care assessment tool and an educational program to prevent burnout.

Enhancing Battery Thermal Management in Li-ion-Powered Electric Vehicles using Phase Change Material-based Systems: A Multi-Scale CFD Simulation Study

Electric cars (EVs) and hybrid electric vehicles (HEVs) are propelled by Li-ion batteries for a clean and sustainable future. Under harsh and abusive conditions, a battery pack generates a lot of heat, which could result in a disastrous thermal runaway. The current work suggests a Battery Thermal Management System (BTMS) based on Phase Change Material (PCM) to prevent thermal runaway. Using ANSYS's multi-scale, multi-dimensional Newman, Tiedemann, Gu, and Kim (NTGK) model, a 3D simulation of a single battery with PCM, is carried out. The thermal performance and discharge behavior of the battery pack is analyzed by the NTGK model. The solidification and melting model is combined with the NTGK for PCM-based BTMS. Under harsh and abusive circumstances, the effect of different discharge rates on the thermal performance of 26650 Li-ion cell with and without PCM is investigated. The PCM-based BTMS reduces the maximum battery temperature by 2.243 K ,1.44 K, and 2.5 K and increases temperature uniformity at 0.5C ,1C and 1.5C discharge rates, respectively. The data available from this research will be useful in the development of passive BTMS for EV applications.

Analysis of ternary hybrid nanofluid in microchannel-cooled cylindrical Li-ion battery pack using multi-scale multi-domain framework

For cylindrical Li-ion battery packs, the battery thermal management system can be properly designed and analyzed from an energy-exergy viewpoint during charging and discharging to ensure the proper functionality of batteries; however, not been explored yet. Hence, cylindrical Li-ion battery pack with novel-designed serpentine microchannel-cooled thermal management system are analyzed. Applying the Multi-Scale Multi-Domain Newman, Tiedemann, Gu, and Kim model, an electrochemical model is used for the 3D battery thermal modeling. Effects of circular and rectangular cross-sectional shaped microchannels and using ternary hybrid nanofluids [THNF1 (Al2O3 (0.5%) + Cu (0.5%) + MWCNT (1%)/water) and THNF2 (Al2O3 (0.5%) + Cu (0.5%) + Graphene (1%)/water] are investigated at a 3C-discharge rate. Results indicate that the use of ternary hybrid nanofluid and microchannel cross-sectional shape has a strong influence. Maximum temperature, temperature uniformity, pumping power, heat transfer coefficient to pressure drop ratio, and entropy generation are the key factors. The present simulation can predict individual battery thermal behavior during charging and discharging. The suggested design successfully lowers the cell temperature to 305.24 K by using THNF2 and the temperature difference to 5.23 K of the 26,650-type cylindrical cell. Rectangular cross-sectioned microchannel is found to be more effective. The thermal control of batteries is greatly enhanced by using ternary hybrid nanofluid. The suggested technique will improve the battery life.

Characteristics of STILT footprints driven by KIM model simulated meteorological fields: implication for developing near real-time footprints

This study presents an analysis of the atmospheric footprint sensitivities and CO2 enhancements measured at three in situ stations in South Korea (Anmyeondo (AMY), Gosan (JGS), Ulleungdo (ULD)) using the KIM-STILT and WRF-STILT atmospheric transport models. Monthly aggregated footprints for each station were compared between the models for July and December 2020. The footprints revealed major source regions and the sensitivity of atmospheric mole fractions at the receptor to upstream surface fluxes. In July, both models showed similar major source regions for the AMY station, including Korea, the Yellow Sea, and Japan. However, a discrepancy was observed in the Eastern Pacific Ocean, with KIM-STILT showing larger sensitivity compared to WRF-STILT. In December, both models indicated strong sensitivity over Northeast and Eastern China, but KIM-STILT exhibited smaller sensitivities towards Northwestern China and Mongolia compared to WRF-STILT. At station ULD in July, both models exhibited comparable source regions, but a notable difference was found in Southeast China, where KIM-STILT showed stronger sensitivity. For the JGS station, both models agreed on major sources, but WRF-STILT demonstrated stronger sensitivity over North and Northeastern China. Regarding CO2 enhancements, both models generally underestimated the amplitude of CO2 enhancements, especially in July. However, in December, there was better agreement with observed data. The models were able to reproduce the phase of measured ΔCO2 reasonably well despite the underestimation of CO2 amplitudes. The contribution of biospheric CO2 to the observed enhancements, along with fossil-fuel emissions, was highlighted. In specific cases with significant CO2 enhancements, the models provided varying estimates of CO2ff values, particularly in the source regions of Eastern China. The differences in sensitivity estimations emphasize the need for further investigation to understand the underlying factors causing disparities. Overall, this study provides valuable insights into the potential advantages of each model in capturing dispersion patterns in specific regions, highlighting the importance of understanding these differences to improve the accuracy of atmospheric transport models. Further work is necessary to address the observed disparities and enhance our understanding of the transport models in the studied regions.

Levitation force approximation of YBCO hybrid superconductors using critical-state theory and partitioning method

Introducing the second-generation coated conductor tapes (2G tapes) can enhance the performance of yttrium-barium-copper-oxide bulk superconductors (SCs) in terms of force, damping, and shape diversity. In this study, we investigate a hybrid SC that utilizes 2G tapes wrapped around the pivotal bulk component to achieve performance improvements. We also present a straightforward method, based on critical-state theory, to approximate the levitation force of this hybrid SC. This method characterizes the stack of tapes as an equivalent bulk with higher anisotropy and applies a fitting Kim model as an integrated expression of J (H) and J anisotropy. The partitioning method divides the SC into several isolated elements where the external field is approximately uniform within each sub-volume. Comparisons of calculated results with experiments indicate that this method can predict levitation properties with reasonable accuracy in just a few seconds. Furthermore, we propose two geometries of hybrid SC, namely, width-hybrid, and height-hybrid SC, for practical applications. Among them, the width-hybrid form exhibits higher efficiency in levitation. Our findings highlight the importance of applying the coated conductor stack when the magnetic field orientation is perpendicular to the a–b planes.

Comparative life cycle environmental assessment of recycled aggregates concrete blocks using accelerated carbonation curing and traditional methods

Accelerated carbonization curing has been a technically feasible alternative to the conventional curing method in the production of recycled aggregate concrete blocks (RACB). However, the environmental impacts of the curing scenarios on production have not yet been studied. Therefore, the paper evaluated the environmental feasibility of curing methods to produce RACB based on the LCA framework. The system boundary from the cradle to the door was selected to compare the overall influence of accelerated carbonation curing methods (pressurized carbonation curing, wet carbonation curing) and traditional curing methods (standard curing, autoclave curing) on the environmental impact. CO2 absorption was calculated by the Kim and Chae carbonation model combined with experimental carbonation depth. Environmental emission calculated from the inventory database was distributed to ten midpoint indicators and three endpoint indicators by the CML 2016 baseline and ReCiPe endpoint method. The distribution of contributions to the environmental impacts of the four production stages (raw material processing stage, raw material transportation stage, block manufacture stage, and block curing stage) was subdivided to facilitate decision-making and improve the management of the block plant. A sensitivity analysis ultimately complements the effect of curing time on the environmental sustainability of RACB production. The results showed that the traditional curing method had a more significant environmental impact, while accelerated carbonization curing had a relatively lower environmental impact. Compared with standard curing, the GWP value of pressurized and wet carbonization curing decreased by 33.3% and 52.8%, respectively. The 1 m3 RACB showed the lowest GWP value of 254.7 kg CO2-eq under wet carbonization curing and the highest GWP value of 539.5 kg CO2-eq under standard curing. The CO2 absorption capacity of −73.0 kg CO2-eq and −99.3 kg CO2-eq was demonstrated by pressurized and wet carbonization curing, respectively. The ranking from all midpoint and endpoint indicators is standard curing > autoclaved curing > pressurized carbonization curing > wet carbonization curing. Contribution analysis based on midpoint indicators showed that the raw material handling stage has the highest percentage contribution. Cement is still the most significant contributor to the environmental impact, followed by significant energy consumption, while water consumption hardly negatively impacts the environment. The results of sensitivity analysis indicate that accelerated carbonation curing (especially wet carbonation curing) is less relevant to the variation of curing time, while conventional curing methods are strongly influenced by curing time.

Presidential Personality and Foreign Policy Decision-Making: The Sunshine Policy under Kim Dae-jung (1998–2003)

This study uses leadership trait analysis to examine the link between personality and policy regarding South Korea's Sunshine Policy toward North Korea and demonstrates that Kim Dae-jung's personality characteristics largely accounted for this policy's content, process, and outcome. With an analytical focus on the decision-making system, this study finds that Kim's formal model was characterized by a control deemed inherently more indirect, subtle, and socialized than direct, personalized, or outright. Specifically, this type of control can be attributed to Kim's personality traits, such as a persistently high need for power and relationship focus, along with other idiosyncratic style variables, such as disinclination toward interpersonal conflict, a sense of efficacy, and a sophisticated cognitive quality. President Kim's resulting management style had the e ect of empowering members of his advisory group and invigorating the policy process. In addition, the president's trusted chief of staff, who served as a competent and thoughtful custodian manager with substantial authority, helped manage the system effectively and enhanced its stability. The study concludes that Kim Dae- jung's management style, incorporating socialized control over decision- making, combined with his advocate leadership style in implementation (marked by a relentless push for his rapprochement agenda and a tendency to challenge constraints indirectly), helped accelerate the overall policy process. This contributed to the improvement of inter-Korean relations during his presidency.

Performance evaluation of a hydrostatic flow immersion cooling system for high-current discharge Li-ion batteries

A Li-ion battery can experience thermal runaway when its temperature rise and temperature distribution are uneven due to fast charging/discharging and extreme hot/cold ambient temperature conditions. In Electric vehicles, a battery thermal management system is used to address these challenges and assure superior battery pack performance. The conventional methods include air and indirect liquid (cold plate) cooling thermal management systems are influencing the high thermal gradients from the top to bottom of the cell and from the cell to cell in a battery pack. Also, when the battery is being discharged at a high current rate, it is difficult to achieve the expected heat dissipation requirements. In order to solve these issues, this research article provides a hydrostatic flow single-phase dielectric immersion cooling technique for an 18,650 cylindrical cell Li-ion battery. The three-dimensional electrochemical-thermal model of an 18,650-cell submerged in dielectric fluid is designed using a Multiscale, Multi-Dimensional (MSMD) approach with the Newman, Tiedemann, Gu, and Kim (NTGK) model. The accuracy of the numerical results is validated as being within 2 °C with experimental data at 3C discharge rate. The experimental results are exhibited a better cooling effect with a 33 % reduction in temperature rise at 3C battery discharge rate in 25 °C ambient temperature. With respect to both 25 °C and 60 °C ambient temperature conditions, this cooling system has a superior cooling effect of <10 °C temperature rise in a cell during a high current (3C) discharge rate. The study showed that at extremely high current discharge rates and various ambient temperature circumstances, the Li-ion battery submerged in a dielectric coolant provides enhanced cooling performance and uniform temperature distribution on the battery surface compared to natural convection. This article highlighted that the immersion cooling technique is an effective cooling phenomenon during electrical abuse conditions.

The concept analysis of helplessness in nurses during the COVID-19 pandemic: A hybrid model.

'Helplessness' is one of the psychological concepts that exploring nurses' helplessness during the COVID-19 pandemic can lead to timely intervention and empowerment of nurses. Concept development. It was carried out using Schwartz-Barcott and Kim's hybrid model. In the literature review, helplessness is characterized by anxiety symptoms (muscle tension, headache, anorexia and insomnia) and, to some extent, depression (loneliness, guilt, apathy and insensitivity). In the fieldwork, five categories were obtained, including antecedents of helplessness (the nature of the disease, professional responsibility, personal lifestyle disruption and social behaviours), attributes of helplessness (inability to do more for the patient, inability to control the situation, feeling of uselessness, frustration, giving up and uncertainty to continue), consequences of helplessness (increase clinical error, physical manifestations and psychological manifestations), strategies to reduce feelings of helplessness and the difference among helplessness, powerlessness and hopelessness. Nurses' helplessness occurs when the nurse has no control over the situation and cannot change it.

Integration of Optical and Free Space Optics Network Architecture for High-Speed Communication in Adverse Weather using suitable Optical Bands

Free Space Optics (FSO) is a highly viable solution for high-speed wireless communication and is widely preferred over radio frequency communication systems because of its faster data transmission, no regulatory requirements and highly secure long-range operations. However, the capacity and availability of FSO optical bands are a significant concern in varying atmospheric conditions. Our objective is to enhance network flexibility and expand wireless network coverage in adverse weather conditions by combining optical and FSO links using optical bands C, S, and O. The study analyzed the performance of a hybrid 4 channels FSO-WDM system with a 100GHz or 0.8 nm channel spacing under different conditions, including adverse weather and varying data rates. An attenuation of 0.25 dB/km was fixed, and the system's performance was analyzed up to 3 km. The results showed that as the data rate increased, the system's performance declined, and the O band was the best performer up to 25 Gbit/s. BER values were analyzed at different weather conditions using the Kim model, and the O band consistently outperformed the S and C bands. Eye diagrams were used to evaluate the signal quality, and the O band was shown to perform better than the other two bands, even in adverse weather conditions. Overall, the study suggests that FSO is a viable solution for high-speed wireless communication, particularly when using the O band.

Optimized cooling and thermal analysis of lithium-ion pouch cell under fast charging cycles for electric vehicles

This study used a multidomain modeling approach to perform a thermal analysis of commercial 65 Ah pouch-type batteries configured in a 1P4S configuration (1 parallel and 4 series battery). The study aimed to analyze the thermal behavior of four different cooling configurations, namely single cell with ambient cooling, 1P4S with ambient cooling, 1P4S with only bottom liquid cooling, and 1P4S with two-side liquid cooling. The Newman, Tiedemann, Gu, and Kim (NTGK) model was used for the subscale electrochemical modeling, while Computational Fluid Dynamics (CFD) was used to analyze the thermal behavior during different fast charging rates that are commonly used for electric vehicles. The results of the study showed that using two cooling plates with opposing flow directions instead of one-side cooling reduced the maximum temperature difference by 50 % from 10 °C to 5 °C and reduced the maximum temperature by 7 °C during charging at 1.98C. This suggests that the use of two-side liquid cooling can significantly improve the thermal performance of the battery, which is essential for fast charging and overall battery performance. The implications of this study for the industry are significant, as it provides insight into how to improve the design and thermal management of battery packs for electric vehicles. By using multidomain modeling and CFD analysis, battery manufacturers can optimize the design of their battery packs to improve thermal management, reduce the risk of thermal runaway, and improve battery performance and longevity. This can lead to the development of more reliable and efficient electric vehicles, which can help to accelerate the adoption of electric vehicles worldwide.

Analysis of Buyer Trust in Web E-Commerce Shop and Travel

The development of information technology is increasing rapidly until now the latest technologies are being developed so that the role of technology can also improve the regional economy. Economic growth and technological developments in the business world have developed very rapidly, marked by the emergence of companies that are trying to create products and services to meet consumer needs. Business development illustrates that people's welfare is increasing, thus causing an increase in people's purchasing power. This study aims to develop a research model that uses Kim's approach model by representing based on Trust, Benefit, Risk, Intention and Purchasing with this model so that factors can be identified. anything that influences public trust to conduct online transactions (E-commerce), especially on web shops and travel.