Power Conditions Research Articles

Load-dependent wear behavior of novel Fe-based amorphous APS coating derived from compositionally modified high-P pig iron

This study examines the wear resistance of a new amorphous coating fabricated by APS thermal spraying using industrial grade pig iron. The coating's performance is evaluated under varying plasma power conditions at three distinct loads of 40, 50, and 60 N. Scanning electron microscope (SEM) micrographs are analyzed to measure the porosity and thickness of each coating. The average porosities (%) of S1-S4 and S5-S8 coatings are 07 ± 03 and 14 ± 04, respectively. The rates of wear between reference mild steel and among all coatings at three different loads are evaluated, compared, and correlated with plasma powers to arrive at optimal level of plasma power. The plasma power of 30–35 kW corresponding to the least wear rate is found to be optimal at three different loads. Further, the generated debris particles are subjected to morphological and phase analysis by scanning electron microscopy and Fourier-transformed infrared spectroscopy. Detailed microstructural analysis of worn surfaces indicates that the wear modes include delamination, abrasion, and oxidation

A study on the fabrication procedure for a high-D/Ti-ratio-deuterated-titanium film on the disk-type neutron generator target

This study aims to present thin film deposition and deuterium adsorption procedure to fabricate disk-type targets with high D/Ti values for a neutron generator and increase their lifespan. The neutron target consists of a titanium thin film with hydrogen loading, and a copper substrate for heat removal. We optimized the incident deuterium ion beam energy and thin film thickness using Geant4 simulations. Additionally, we calculated the expected neutron yield under the optimized conditions. The hydrogen adsorption conditions were optimized by comparing the H/Ti results as per hydrogen adsorption temperature and loading time using titanium foils of different thickness values. Hydrogen (or deuterium) adsorption ratio is strongly influenced by the surface condition and the deposition conditions of the thin film. A titanium film was deposited in various conditions of plasma DC power and substrate temperature. The quality of the thin film was evaluated through surface roughness evaluation and thin film sheet resistance for each deposition conditions. Subsequently, the hydrogen adsorption results were compared according to the quality of the thin titanium films, and the thin titanium film deposition conditions with the highest hydrogen adsorption ratio were confirmed. The selected conditions were applied to conduct deuterium adsorption. In conclusion, this study underscores the critical relationship between thin film quality and hydrogen (or deuterium) adsorption ratio, reinforcing the importance of optimizing thin film deposition parameters for the design of neutron generator disk-type targets with high quality of film and extended lifespan.

State of the Art of Renewable Sources Potentialities in the Middle East: A Case Study in the Kingdom of Saudi Arabia

The Kingdom of Saudi Arabia is experiencing a surge in electricity demand, with power generation increasing 4 times in 25 years from 1990 to 2014. Despite the abundant primary renewable energy sources, the country has overlooked them in the past in national energy policies. However, in recent years, renewable energy has become a part of the Kingdom of Saudi Arabia’s energy conservation policy due to climate changes, technological progress, economies of scale, and increased competitiveness in supply chains. The Saudi government has created the King Abdullah City for Atomic and Renewable Energy (KACARE) to develop national strategies for effectively utilizing renewable and nuclear energy. This paper reviews the current state of the art of the renewable energy technologies available on the market and evaluates the installation of renewable energy plants near Saudi Arabia’s East Coast for a new town, focusing on technical rather than economic aspects. The paper provides a wide review of the possible technical solutions to exploit the producibility of different renewable sources, considering the challenging climate conditions typical of desert areas. The analysis of a real case study shows a high availability of wind and solar irradiance that allow a net energy production of 354 and 129 GWh, respectively. In addition, the comparison between a typical ground-mounted photovoltaic (PV) system and an emerging floating PV reveals that for the same installed power, occupied area, and environmental conditions, the latter has a 4% greater performance ratio due to the cooling effect of water.

Dynamic thermal response characteristics of a metal foam enhanced horizontal loop thermosyphon

A metal foam horizontal loop thermosyphon (MF-HLTS) for a solar receiver was proposed and investigated under the variable conditions. Meanwhile, a dynamic response model for predicting the thermal response characteristics of MF-HLTS was established using Nusselt theory and lumped parameter method. Results of the dynamic model show good agreement with the experimental data, with a maximum deviation of 3.5 % for temperature response. Under sudden power conditions, the temperature variation curve of MF-HLTS shows a progressive monotonic change with two stages: both rising and decreasing rates of temperature show linear and rapidly changes at first stage, and them begins to decrease and gradually tends to 0 at second stage. The time required to reach steady-state increases with the increase of power step. For start-stop of power and cooling, the recovery time gradually increases with increasing stop time, but start-stop ratio firstly decreases rapidly and then tends to be flat. Dynamic response of MF-HLTS is relatively fast with a temperature time lag of 2 s to 4 s, which can meet the requirements of dynamic regulation of system temperature under actual conditions.

Effect of width on the fire spreading characteristics of PE metal sandwich panels under the action of double fire sources

The exterior walls of high-rise buildings typically contain substantial thermal insulation materials. Once ignited, these materials can readily induce major fire accidents. In this study, through the constructed reduced-size experimental bench to evaluate the effect of window overflow fire and upper chamber fire on the fire spreading properties of PE metal sandwich panels with different widths. The result shows that the average flame height and flame oscillation intensity increased with an increase in fire source power and sandwich panel width. Temperature curves exhibited a consistent trend under different working conditions. Dimensionless analysis of the sandwich layer temperature indicated that under specific fire source power conditions, the 60 cm sandwich panel reached the highest peak temperature and posed the greatest fire hazard. Based on the width and length of the preheating zone, a model for the rate of flame spreading was created. At a constant sample width, the accelerated spread of the upper part of the plate by the action of fire source B was more obvious. These conclusions are instructive for the study of building facade fire.

Modelling the power threshold and optimum thermal deformation of indirectly liquid-nitrogen cryo-cooled Si monochromators.

Maximizing the performance of crystal monochromators is a key aspect in the design of beamline optics for diffraction-limited synchrotron sources. Temperature and deformation of cryo-cooled crystals, illuminated by high-power beams of X-rays, can be estimated with a purely analytical model. The analysis is based on the thermal properties of cryo-cooled silicon crystals and the cooling geometry. Deformation amplitudes can be obtained, quickly and reliably. In this article the concept of threshold power conditions is introduced and defined analytically. The contribution of parameters such as liquid-nitrogen cooling efficiency, thermal contact conductance and interface contact area of the crystal with the cooling base is evaluated. The optimal crystal illumination and the base temperature are inferred, which help minimize the optics deformation. The model has been examined using finite-element analysis studies performed for several beamlines of the Diamond-II upgrade.

Beta spending function based on conditional power in group sequential design.

Conditional power (CP) serves as a widely utilized approach for futility monitoring in group sequential designs. However, adopting the CP methods may lead to inadequate control of the type II error rate at the desired level. In this study, we introduce a flexible beta spending function tailored to regulate the type II error rate while employing CP based on a predetermined standardized effect size for futility monitoring (a so-called CP-beta spending function). This function delineates the expenditure of type II error rate across the entirety of the trial. Unlike other existing beta spending functions, the CP-beta spending function seamlessly incorporates beta spending concept into the CP framework, facilitating precise stagewise control of the type II error rate during futility monitoring. In addition, the stopping boundaries derived from the CP-beta spending function can be calculated via integration akin to other traditional beta spending function methods. Furthermore, the proposed CP-beta spending function accommodates various thresholds on the CP-scale at different stages of the trial, ensuring its adaptability across different information time scenarios. These attributes render the CP-beta spending function competitive among other forms of beta spending functions, making it applicable to any trials in group sequential designs with straightforward implementation. Both simulation study and example from an acute ischemic stroke trial demonstrate that the proposed method accurately captures expected power, even when the initially determined sample size does not consider futility stopping, and exhibits a good performance in maintaining overall type I error rates for evidentfutility.

SISTEM PENTRU DIAGNOSTICAREA COMPLEXĂ A STĂRILOR MAȘINILOR ELECTRICE ROTATIVE DE MEDIE ȘI MARE PUTERE (ACRONIM SDCME)

The company SIMTECH RESEARCH SRL completed, in the year 2023, the Project entitled System for the complex diagnosis of the condition of medium and high power rotating electrical machines - acronym SDCME, and in this work the objectives, activities and results of this project are briefly presented, together with the conclusions resulting from the realization of the project, as well as some perspectives on future research.

Bespoke climate indicators for the Swedish energy sector − a stakeholder focused approach

Climate change concerns the energy sector to a high degree because the sector is sensitive both to changing conditions for power and heat production, and to changing demand for electricity, heating and cooling. In this study potential consequences of climate change on different parts of the Swedish energy sector were assessed in a series of workshops, where climate and energy scientists, energy systems experts and analysts met with representatives of the energy sector to assess the vulnerability of the sector and consider what climate indicators could be used to assess impacts of relevance.The impact of climate change depends on the energy type. Hydropower, for which production is naturally linked to weather and climate, is significantly impacted by climate change. For other forms of production, such as nuclear power, other factors such as e.g. policy and technology development are more important. The series of workshops held in this study, where different aspects of climate change and consequences were discussed, proved very successful and has increased our understanding of climate impacts on the energy system.

Shaping Ethnoracial Identities: State-Society Relations and Programmatic Differentiation in the Andes

Under what circumstances do ethnoracial groups become programmatically differentiated? This article argues that ethnoracial programmatic differentiation results from major transformations in groups’ access to state power. Access to state power conditions ethnoracial groups’ perceptions of the state and their support for state-centric programmatic policies. As historically-excluded groups gain access to power, and historically-advantaged ones lose theirs, programmatic differentiation increases, the product of shifting relationships with the state. I evaluate this argument using survey data from the Andean region and demonstrate that ethnoracial groups have become programmatically differentiated where the indigenous have recently gained political power, but not elsewhere despite widespread structural inequalities and extensive indigenous organizational capacity. The findings shed light on why ethnoracialized preferences vary across contexts in unexpected ways.

Mechanism Analysis and Experimental Research on Leaching Zn from Zinc Oxide Dust with an Ultrasound-Enhanced NH3-NH4Cl-H2O System

Zinc oxide dust (ZOD) is an industrial solid waste produced in the production process of wet smelting Zn, with large output and great pollution to the environment. The recycling of metallurgical solid waste such as zinc oxide dust is very important to achieve the sustainable development of the circular economy. An experimental study of zinc (Zn) leaching from zinc oxide dust using an ultrasound-enhanced ammonia–ammonium chloride system was performed. The effects of ultrasonic power, leaching time, total ammonia concentration, and other factors on the leaching rate of zinc from zinc oxide dust were investigated. The results revealed that the leaching rate of Zn reached up to 80.70% under the condition of ultrasound power of 1000 W, reaction time of 15 min, total ammonia concentration of 6 mol/L, [NH3]:[NH4+] of 1:1, L/S of 5:1, temperature of 45 °C, and stirring speed of 100 r/min. The conventional leaching was conducted under similar conditions, except that the time was controlled to 40 min and the zinc leaching rate was 71.15%. The leaching rate of Zn in the ultrasound condition was improved by 9.55% compared with that in the conventional leaching process. XRD, laser particle size, and SEM-EDS analyses were conducted to study the leaching residues of ZOD. The analysis results showed that in the ultrasound condition, the largest leaching rate of soluble ZnO phases was achieved after 15 min of leaching. Under the ammoniacal system, it was difficult to leach ZnFe2O4, Zn2SiO4, and ZnS phases, which partly accounted for the low zinc leaching rate. Additionally, through ultrasound-enhanced treatment, the ZnO particles encapsulated in ZOD particles were broken into smaller sizes and exposed to the leaching solution. Thus, the leaching rate of Zn was improved. The experimental results show that ultrasound can tremendously improve the effect of Zn extraction from ZOD, shorten reaction time, and help reduce energy consumption and environmental pollution, making it a promising application in the treatment of secondary Zn resources.

Influence of RF power in the sputter deposition of amorphous InGaZnO film on the transient drain current of amorphous InGaZnO thin-film transistors

The device electrical and transient current characteristics of the amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) are comprehensively investigated according to the radio-frequency (RF) power during the sputter-deposition of IGZO active film. The RF power dependencies of the oxygen vacancy (VO) concentration in IGZO and the surface morphology of IGZO film are analyzed through X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). According to the RF power change in the range of 100 ∼ 250 W, the optimal point in terms of threshold voltage (VT), ON current (Ion), field-effect mobility in the linear region (μFE_lin), hysteresis voltage (VHys), and the VT shift under current stress (ΔVT) is found to be 200 W. The existence of the optimal power condition originates from the RF-power dependencies of the electron carrier concentration, the density of electron traps in gate insulator (GI), and the interface trap density related to surface roughness.Furthermore, compared to the direct current (DC) current stress (CS) condition, it is found that when VGS rises rapidly, a total transient current ΔID can be decomposed into three components, i.e., ΔIOS, ΔIBOOST, ΔIDEG. While ΔIOS is attributed to the non-quasi static Fermi-level rising, ΔIBOOST and ΔIDEG result from the donor creation in IGZO and the electron trapping into GI and interface. Noticeably, the occurrence level of each component changes sensitively according to RF power.Our result suggests that the 200 W device has the least overshoot of transient current and shows the best reliability in terms of deterioration due to transient current characteristics.

Vibration Energy Harvesting with Printed P(VDF:TrFE) Transducers to Power Condition Monitoring Sensors for Industrial and Manufacturing Equipment

A vibration energy harvesting system based on fully printed piezoelectric transducers is realized. The transducers have a butterfly‐like architecture based on two single‐optimized cantilevers with a resonance frequency tuned to 49.5 Hz and can be easily mounted to an industrial engine. By comparing single‐ and multistack configurations of the piezoelectric layers combined with full‐wave or voltage doubler rectifiers, the power transfer characteristics and impedance can be matched to the electrical requirements of the sensing circuitry. A single stack with 21 μm thickness results in the maximum power output of 14.4 μW at a vibration velocity of 11.5 mm s−1, typical for industrial engines. The system is used to power a wireless sensor node on a 1 kW rotary pump in normal operation. The system can harvest up to 138 mJ within 24 h, sufficient for daily remote monitoring of the engine's vibration spectrum and temperature state. The system is thus suitable as a low‐cost, ecofriendly power source for industrial IoT applications.

Calculation and measurement of trapping stiffness in femtosecond optical tweezers.

Due to the characteristics of ultra-short pulse width and ultra-high peak power, femtosecond pulse laser can effectively induce nonlinear optical effects in trapped objects. As a result, it holds great value in the fields of micro and nano manipulation, microfluidics, and cell biology. However, the nonlinear optical effects on the stiffness of femtosecond optical traps remain unclear. Calibration of trap stiffness is crucial for accurately measuring forces and manipulating small particles. In this paper, we compare the stiffness between femtosecond optical traps and continuous wave optical traps. Experimental results demonstrate that the stiffness of the femtosecond optical trap in the splitting direction is greater than that in other directions and the stiffness of the continuous wave optical trap under the same laser power condition. Additionally, as the laser power increases, the stiffnesses of both the femtosecond optical trap and the continuous wave optical trap gradually increases. In contrast to a linear increase of the continuous wave optical trap, the stiffness of the femtosecond optical trap exhibits an exponential rise with increasing laser power. This research provides guidance and reference for improving the force measurement accuracy of femtosecond optical tweezer system.

Numerical study of the induction of intratumoral apoptosis under microwave ablation by changing slot length of microwave coaxial antenna.

Recent advances in technology have led to an increase in the detection of previously undetected deep-located tumor tissue. As a result, the medical field is using a variety of methods to treat deep-located tumors, and minimally invasive treatment techniques are being explored. In this study, therapeutic effect of microwave ablation (MWA) on tumor generated inside liver tissue was analyzed through numerical analysis. The distribution of electromagnetic fields in biological tissues emitted by microwave coaxial antenna (MCA) was calculated through the wave equation, and the thermal behavior of the tissue was analyzed through the Pennes bioheat equation. Among various treatment conditions constituting MWA, tumor radius and the slot length inside the MCA were changed, and the resulting treatment effect was quantitatively confirmed through three apoptotic variables. As a result, each tumor radius has optimal power condition for MWA, 2.6W, 2.4W, and 3.0W respectively. This study confirmed optimal therapeutic conditions for MWA. Three apoptotic variables were used to quantitatively identify apoptotic temperature maintenance inside tumor tissue and thermal damage to surrounding normal tissue. The findings of this study are expected to serve as a standard for treatment based on actual MWA treatment.

From wide to ultrawide-bandgap semiconductors for high power and high frequency electronic devices

Abstract Wide and ultrawide-bandgap (U/WBG) materials have garnered significant attention within the semiconductor device community due to their potential to enhance device performance through their substantial bandgap properties. These exceptional material characteristics can enable more robust and efficient devices, particularly in scenarios involving high power, high frequency, and extreme environmental conditions. Despite the promising outlook, the physics of UWBG materials remains inadequately understood, leading to a notable gap between theoretical predictions and experimental device behavior. To address this knowledge gap and pinpoint areas where further research can have the most significant impact, this review provides an overview of the progress and limitations in U/WBG materials. The review commences by discussing Gallium Nitride, a more mature WBG material that serves as a foundation for establishing fundamental concepts and addressing associated challenges. Subsequently, the focus shifts to the examination of various UWBG materials, including AlGaN/AlN, Diamond, and Ga2O3. For each of these materials, the review delves into their unique properties, growth methods, and current state-of-the-art devices, with a primary emphasis on their applications in power and radio-frequency electronics.

Multi-objective optimisation of heat transfer and structural strength of aero-piston air-cooled engine cylinder based on orthogonal test

Owing to their compact and lightweight structure, air-cooled aviation piston engines are used in general aviation, agriculture, and military fields. To address the kind of engine thermal load problem, this study used a horizontal four-cylinder four-stroke aviation piston air-cooled gasoline engine as the research object. Tested the engine cylinder temperature and pressure under calibrated power conditions, built a one-dimensional simulation model and a fluid–structure interaction simulation model. Four main structural parameters—fin thickness, fin spacing, fin length, and cylinder wall thickness—were considered as factors. Each factors have five levels to construct orthogonal tests to analyse their influence on the cylinder heat transfer and structural strength performance. A range analysis of the orthogonal test showed that the fin thickness had the most significant influence on the thermal stress, while the fin length most significantly influenced the temperature and cylinder hole deformation. A comprehensive frequency analysis method combining intuitive and range analyses is used to determine the optimal combination scheme, and the heat transfer and strength performance of the engine cylinder before and after optimization is compared. The results indicated that the fin thickness and length had the most influence on cylinder performance. After optimisation, the temperature decreased by 3.3 % from 198.3 ℃ to 191.8 ℃, while the thermal stress decreased by 21.9 % from 100.5 MPa to 78.5 MPa. In addition, the cylinder hole deformation decreased by 11 %, from 0.273 mm to 0.243 mm. These research results can provide a reference for the design and optimisation of heat fins of air-cooled aviation piston engines.

Diagnosis of multiple gases using a multi-pass ring cavity to enhance Raman scattering

Spontaneous Raman scattering is widely used to enable simultaneous concentration measurements of all relevant species with overcomes whose signal is weak and susceptible to fluorescence interference. A multi-pass ring-cavity scheme is proposed to enhance Raman scattering signal. The Raman spectra of CO2, N2, O2 and H2O in the air are acquired under condition of low excitation power which is 200 mW laser of 532 nm. Compared with the results obtained by single collection without ring cavity, the Raman signal level is enhanced 40 times and the signal-to-noise ratio is improved by 43 times at maximum. Power of pump is taken into consideration to analyze its impact on signal. A limit of detection (3σ criterion standard) of 83 ppm for CO2 is calculated for the multi-pass ring-cavity. The limit of detection of 14 ppm for CH4 is also estimated by the theoretical ratio of cross section values of CO2 and CH4. When power of excitation is low, high level of signal of multi-species gases is acquired with fine detection sensitivity through ring cavity.

Experimental Research on the Carbon Dioxides Reduction Potential by Substitution Gasoline with Ethanol and Propane Under Reactivity Controlled Compression Ignition in a Single Cylinder Engine

In this experiment, it was experimentally investigated the combustion and exhaust characteristics, as well as the thermal efficiency, of RCCI combustion using gasoline, ethanol, and propane as low-reactivity fuels under four operating conditions. For each operating condition, gISNOx was limited to 0.15 g/kWh, and gISSmoke was limited to below 15 mg/kWh. The experiment was conducted by determining the operating conditions that satisfied these limitations and resulted in the highest city thermal efficiency. The low-reactivity fuels were supplied by port injection, while diesel was directly injected into the combustion chamber using a diesel injector. As a result, when gasoline is replaced with low-carbon fuels like ethanol and propane, the reduction in CO2 emissions occurred. Under maximum power conditions, using ethanol allowed for a maximum reduction in CO2 emissions of 6.81%. Depending on the driving conditions, ethanol showed a reduction ranging from 3.60 to 6.81%, while propane exhibited a reduction ranging from 3.10 to 5.64%. Additionally, by substituting with ethanol and propane, the GIE could be improved up to 44.73 and 43.56%, respectively.

الثقافة الحاسوبية لدى تدريسيي الجامعة

The current research aims to identify: . 1- Management of wisdom among postgraduate students 2- Differences in the management of wisdom among postgraduate students according to the variables of gender (male - female), academic specialization (scientific - human) and type of study (Master's – PhD). In order to achieve the objectives of the research, the researcher relied on the following: 1- Using the (descriptive-relational approach) to detect wisdom management. 2-Building the wisdom management scale according to the theory of (Sternberg 2004), and the scale consisted in its final form after completing the conditions of honesty, stability, discriminatory power, and internal consistency, from (33) items. As a complement to this, the researcher applied the scale to a sample of (400) male and female postgraduate students, who were selected using the stratified random method of a proportional method. After collecting the data and processing it statistically using the Statistical Bag for Social Sciences (SPSS). The search results found: . - Graduate students have a management of wisdom - The results showed that the difference between males and females on the wisdom management scale is statistically significant, and in favor of males. The results also showed that the difference between scientific and human specialization on the wisdom management scale is not statistically significant. Statistically. As a complement to the findings of the research, the researcher recommended several recommendations and proposals. Keywords: wisdom management.