First-Principles Investigation of Charge Transfer Mechanism of B-Doped 3C-SiC Semiconductor Material

This study delves into the charge transfer mechanism of boron (B)-doped 3C-SiC through first-principles investigations. We explore the effects of B doping on the electronic properties of 3C-SiC, focusing on a 12.5% impurity concentration. Our comprehensive analysis encompasses structural properties, electronic band structures, and charge density distributions. The optimized lattice constant and band gap energy of 3C-SiC were found to be 4.373 Å and 1.36 eV respectively, which is in agreement with previous research (Bui, 2012;Muchiri et al., 2018). Our results show that B doping narrows the band gap, enhances electrical conductivity, and influences charge transfer interactions. The charge density analysis reveals substantial interactions between B dopants and surrounding carbon atoms. This work not only enhances our understanding of the material’s electronic properties, but also highlights the importance of charge density analysis for characterizing charge transfer mechanisms and their implications in the 3C-SiC semiconductors.

Effect of sinter layer porosity distribution on flow and temperature fields in a sinter cooler

When sinters are filled into the sinter cooler from the sintering machine, it is commonly seen that, due to segregation effects, sinters of larger size usually accumulate closer to the inner wall of the sinter cooler, whereas those of smaller size are to the outer wall. This nonuniform distribution of sinters has led to uneven cooling effect throughout the cooler. This causes the sinters leaving the cooler at a large temperature difference. This undesired temperature difference leads to the deformation and even the destruction of the conveyors. The computational fluid dynamics （CFD） technique was used in the present work to investigate the heat and fluid flow phenomena within the sinter cooler corresponding to the different distribution of sinter layer porosity, which was highly dependent on the arrangement and orientation of sinters within the sinter cooler. It is confirmed that a high mass flow rate within the sinter layer causes a low temperature region and vice versa. The flow fields for vertically reducing porosity distribution and random distribution are almost identical indicating the relative insignificance of convective heat transfer mechanism.

Numerical Simulations of a Florida Sea Breeze and Its Interactions with Associated Convection:Effects of Geophysical Representation and Model Resolution

The Florida peninsula in the USA has a frequent occurrence of sea breeze(SB)thunderstorms.In this study,the numerical simulation of a Florida SB and its associated convective initiation(CI)is simulated using the mesoscale community Weather Research and Forecasting(WRF)model in one-way nested domains at different horizontal resolutions.Results are compared with observations to examine the accuracy of model-simulated SB convection and factors that influence SB CI within the simulation.It is found that the WRF model can realistically reproduce the observed SB CI.Differences are found in the timing,location,and intensity of the convective cells at different domains with various spatial resolutions.With increasing spatial resolution,the simulation improvements are manifested mainly in the timing of CI and the orientation of the convection after the sea breeze front(SBF)merger into the squall line over the peninsula.Diagnoses indicate that accurate representation of geophysical variables(e.g.,coastline and bay shape,small lakes measuring 10-30 km2),better resolved by the high resolution,play a significant role in improving the simulations.The geophysical variables,together with the high resolution,impact the location and timing of SB CI due to changes in low-level atmospheric convergence and surface sensible heating.More importantly,they enable Florida lakes(30 km2 and larger)to produce noticeable lake breezes(LBs)that collide with the SBFs to produce CI.Furthermore,they also help the model reproduce a stronger convective squall line caused by merging SBs,leading to more accurate locations of postfrontal convective systems.

Dynamic Simulation and Hemolysis Evaluation of the Regurgitant Flow over a Tilting-Disc Mechanical Heart Valve in Pulsatile Flow

Regurgitation in the heart diastolic phase represents a critical flow condition associated with many heart valve design considerations. The finite volume method, the Low-Reynolds-Number k-ω turbulent model and sliding mesh model are employed to solve and compare the complex flow field and the torque in each case. The end results expected from a cardiovascular CFD analysis are not limited only to the flowfield investigations. More importantly, it needs an evaluation criterion to judge if the design is acceptable as considered from a broader blood cell damage or activation perspective. In this study, blood cell damage index developed based on stress-time empirical rule and Lagrangian particle tracking is introduced to assess the viscous and turbulence-induced stresses effect to the blood cells.

Hot Cracking Susceptibility of 800H and 825 Nickel-Base Superalloys during Welding via Spot Varestraint Test

Hot cracking susceptibility of fillers 52 and 82 in 800H and 825 nickel-base superalloys was discussed using the Spot Varestraint test.The fillers of 52 and 82 were added into nickel-base superalloys via a gas tungsten arc welding(GTAW).Experimental results showed that the hot cracking sensitivity of the nickel-base superalloys with filler at high temperature was lower than that without filler.The hot cracking sensitivity had a slight effect when the filler 82 was added.The total length of crack was increased,the liquid-solid(L-S)two-phase range is higher so that the hot cracking susceptibility will be raised.The morphologies of cracks included the intergranular crack in the molten pool,molten pool of solidification cracking,heat-affected zone of intergranular cracks,and transgranular crack in the heat-affected zone.

Bio-drilling, Compaction Alleviation, and Fate of Storm-Water Management

Compaction due to urbanization and farm operations disrupt natural soil profiles,increase impervious surface areas and decrease vegetative cover.These disruptions increase storm-water runoff at the expense of ground water recharge,degrading water quality and impairing aquatic habitats.A completely randomized experiment was conducted at the OSU/South Centers,Piketon,OH to assess the effect of Daikon radish(Raphanus sativus L.var.oleiferus)on alleviating compaction.Treatments included long-term tillage,long-term no-till(NT)and a fallow soil compacted with farm equipment with and without Daikon radish.Radish was sown in mid-August and plants were winter-killed at the onset of first frost when the temperature dropped to-2.22°C(28°F).To assess progress in compaction alleviation,a model was developed to extrapolate information on soil porosity as an indicator of hydrological properties of soils.Earthworm population dynamics were also considered as a bio-indicator of compaction alleviation.The adoption of radish used as bio-drilling,alleviated overall compaction by 40%with reductions ranging from 90%at 0-13 cm to 30%at 56-64 cm depth.The fallow compacted soil with radish had the highest population of earthworm with total body mass of 3.6 kg·m-3,followed by NT at 0.8 kg·m^-3,and till at 0.4 kg·m^-3(p<0.05).Mean values of soil porosity were increased by 44%with radish compared to the fields without radish.This increase ranged from 71%in the upper soil depths(0-13 cm depth)to 25%in the lower depths(56-64 cm depths).Use of bio-drilling has potential to synergistically alleviate the effect of compaction,minimize flash-flooding and improve water quality.

A Life Cycle Comparison of Remote, Deployed Expeditionary Waste Management Scenarios

The current barrier to acquisition and utilization of viable waste-to-energy (WTE) technologies at remote or deployed expeditionary sites requires high capital and operation & maintenance costs. The impacts to environment and human health of differing expeditionary waste management strategies were compared using the Life Cycle Assessment software SimaPro 8.0. Emissions of individual waste management scenarios were compiled from peer-reviewed literature, converted to values compatible with SimaPro’s waste scenario inputs, and the calculated impacts compared using SimaPro’s pre-loaded methodologies. These calculated impacts and the economic impacts confirm that open-air burning of waste is not only dangerous to humans and the environment, but is also not cost-effective. Considering the economic effects and the mitigated human and environmental health impacts, WTE technologies may be a viable waste management strategy for the future.

A Life Cycle Assessment Based Evaluation of a Coupled Wastewater Treatment and Biofuel Production Paradigm

A laboratory experiment was performed to determine the feasibility of coupling a conventional wastewater treatment system with an algal photobioreactor (PBR) for the removal of nutrients from wastewater and production of renewable resources. An activated sludge batch reactor was set up in series with an algal PBR to feed synthetic wastewater to Chlorella vulgaris. The nutrient concentration in the water as well as lipid content, carbohydrate content, and growth rate of the algal biomass were tested over 10 cycles to determine the capabilities of the coupled system. The study revealed complete nutrient removal in some cycles, with the average final nutrient content of 2 mg-P/L and 3 mg-N/L in effluent of the PBR. The algae biomass contained 24% ± 3% lipids and 26% ± 7% carbohydrates by dry weight. A life cycle assessment revealed the highest energy demand occurred during harvesting of the algal mixture through centrifugation or filtration, but the highest global warming and eutrophication impacts were due to CO2 use and PBR construction material production. It is feasible for the system to treat wastewater while generating renewable resources, but the system must be optimized to reduce life cycle environmental impacts and result in a net energy gain before large-scale implementation is possible.

Design and Characterization of an Aerosol Test Chamber for Emergency Response Patient Contamination Control Simulation and Research

Contaminated or infected patients present a risk of cross-contamination for emergency responders, attending medical personnel and medical facilities as they enter a treatment facility. The controlled conditions of an aerosol test chamber are required to examine factors of contamination, decontamination, and cross-contamination. This study presents the design, construction, and a method for characterizing an aerosol test chamber for a full-sized manikin on a standard North Atlantic Treaty Organization litter. The methodology combined air velocity measurements, aerosol particle counts and size distributions, and computational fluid dynamics modeling to describe the chamber’s performance in three dimensions. This detailed characterization facilitates future experimental design by predicting chamber performance for a variety of patient-focused research.

Discrete Event Simulation-Based Evaluation of a Single-Lane Synchronized Dual-Traffic Light Intersections

This research involved an exploratory evaluation of the dynamics of vehicular traffic on a road network across two traffic light-controlled junctions. The study uses the case study of a one-kilometer road system modelled on Anylogic version 8.8.4. Anylogic is a multi-paradigm simulation tool that supports three main simulation methodologies: discrete event simulation, agent-based modeling, and system dynamics modeling. The system is used to evaluate the implication of stochastic time-based vehicle variables on the general efficiency of road use. Road use efficiency as reflected in this model is based on the percentage of entry vehicles to exit the model within a one-hour simulation period. The study deduced that for the model under review, an increase in entry point time delay has a domineering influence on the efficiency of road use far beyond any other consideration. This study therefore presents a novel approach that leverages Discrete Events Simulation to facilitate efficient road management with a focus on optimum road use efficiency. The study also determined that the inclusion of appropriate random parameters to reflect road use activities at critical event points in a simulation can help in the effective representation of authentic traffic models. The Anylogic simulation software leverages the Classic DEVS and Parallel DEVS formalisms to achieve these objectives.

Expert System for the Diagnosis and Prognosis of Common Dental Diseases Using Bayes Network

Expert systems are being utilized increasingly in medical fields for the purposes of assisting diagnosis and treatment planning. Existing systems used few symptoms for dental diagnosis. In Dentistry, few symptoms are not enough for diagnosis. In this research, a conditional probability model (Bayes rule) was developed with increased number of symptoms associated with a disease for diagnosis. A test set of recurrent cases was then used to test the diagnostic capacity of the system. The generated diagnosis matched that of the human experts. The system was also tested for its capacity to handle uncommon dental diseases and the system portrayed useful potential.

How to Support Communication among Stakeholders during Software Requirements Prioritization

Existing prioritization techniques do not support communication among stakeholders and this makes it difficult for stakeholders to understand the meaning and essence of requirements before prioritization commences. When this happens, the ordered list of requirements can be misleading. The aim of this research is to develop a method capable of supporting and computing ranks of requirements based on the criteria defined for each requirement. The proposed method is developed based on fuzzy logic. Results show that ordered requirements reproduced ranks with strong correlations when compared to their linguistic values provided by the stakeholders. The contribution of this paper centers on an improved way of prioritizing requirements with understanding.

The economic impacts of cataract surgery on sustainable vision and quality of life in Katsina state

Background:This study investigates the economic impacts of eye care interventions on the quality of life in Katsina state.Eye care intervention is a requirement for equitable and inclusive development in the state.Methods:The study used a survey method and 5-point Likert scale questionnaire to collect data.A multistage sampling strategy was employed to select 300 beneficiaries from the existing beneficiaries of Noor Dubai Foundation(NDF)eye care interventions.Results:The findings show that cataract surgery interventions improve economic benefits and quality of life of beneficiaries in Katsina state.The results show that productivity,income,employability,dignity and skills of beneficiaries have improved significantly after the cataract surgery.Precisely,96.2%of the beneficiaries agree that their productivity has improved;99.6%of the beneficiaries revealed that their income has improved;99%of respondents evidence that their employability has improved;90%of beneficiaries have experienced an improvement in their dignity;while 97%agreed that their skills have improved.Conclusion:The implication of these findings is that poor eye health is negatively related to economic benefits and quality of life while good eye health is a vital determinant of standard of living.Without good eye health,it is hard to participate in the labour force,produce goods and earn income.Thus,the Katsina state government should further improve awareness of good eye health to mitigate preventable cases of blindness for equitable and inclusive development.

Machine Learning Models for Heterogenous Network Security Anomaly Detection

The increasing amount and intricacy of network traffic in the modern digital era have worsened the difficulty of identifying abnormal behaviours that may indicate potential security breaches or operational interruptions. Conventional detection approaches face challenges in keeping up with the ever-changing strategies of cyber-attacks, resulting in heightened susceptibility and significant harm to network infrastructures. In order to tackle this urgent issue, this project focused on developing an effective anomaly detection system that utilizes Machine Learning technology. The suggested model utilizes contemporary machine learning algorithms and frameworks to autonomously detect deviations from typical network behaviour. It promptly identifies anomalous activities that may indicate security breaches or performance difficulties. The solution entails a multi-faceted approach encompassing data collection, preprocessing, feature engineering, model training, and evaluation. By utilizing machine learning methods, the model is trained on a wide range of datasets that include both regular and abnormal network traffic patterns. This training ensures that the model can adapt to numerous scenarios. The main priority is to ensure that the system is functional and efficient, with a particular emphasis on reducing false positives to avoid unwanted alerts. Additionally, efforts are directed on improving anomaly detection accuracy so that the model can consistently distinguish between potentially harmful and benign activity. This project aims to greatly strengthen network security by addressing emerging cyber threats and improving their resilience and reliability.

利用Agent实现新的电网后备保护

提出了一种新的利用Agent实现的电网后备保护系统。它优于由传统第Ⅲ段保护构成的后_ 备保护系统,动作更快而且更具有选择性,其自检和纠错能力能减少保护的不正确动作。阐述了Agent的基本思想,分析了Agent保护通信特点,提出了基于Agent的电网后备保护系统原理结构、算法和IP通信实现,利用电力和通信系统同步仿真平台EPOCHS在一简单电力系统上对所提出的保护系统进行了仿真实现,证明了所提出的方法的有效性。

碳纳米管纱作为填料应用于硝基芳烃污水处理（英文）

碳纳米管纱(CNTY)因具有优异的力学强度、化学稳定性、热稳定性和高比表面积而成为去除废水中有机污染物的潜在材料。本文将CNTY用于含2,4-二硝基甲苯(DNT)的污水处理。CNTY对DNT的吸附能力与文献报道值作对比研究,同时探讨吸附动力学。采用SEM-EDX、HRTEM、Raman与XPS表征CNTY吸附DNT前后的尺寸、表面形貌及表面化学。结果表明,经CNTY对DNT污水处理后的水质达到实验室无离子水级纯度。CNTY对DNT吸附符合Freundlich吸附等温线,Freundlich参数由K/nF为55.0 mg/g(L/mg)1,指数1/n为0.737得到,表明其比活性炭吸附性弱,但更易再生。CNTY比活性炭的吸附性速率更快,遵循拟二级动力学模型。CNTY吸附DNT引起D、G常偏移,归因于CNTs与DNT间电子受体和供体效应。

Using Inductance as a Tuning Parameter for RF Meta-atoms

The resonant frequency of metamaterials structured with split ring resonator(SRR) meta-atoms is determined primarily through the capacitance and inductance of the individual meta-atoms. Two designs that vary inductance incrementally were modeled, simulated, fabricated, and tested to investigate the role inductance plays in metamaterial designs. The designs consisted of strategically adding sections to the SRR to increase the inductance, but in a manner that minimized capacitance variations. Each design showed a shift in resonant frequency that was proportional to the length of the added section. As the length of each section was increased, the resonant frequency shifted from 2.78 GHz to 2.18 GHz.

碳纳米管纱的时间依赖电性能(英文)

碳纳米管(CNTs)在电力转换领域具有潜在前景。本文表征碳纳米管纱随时间变化对电力的转换性能影响。通过建立I-V关系,结果表明存在3个区域,即线性、非线性和下降区域。线性区域表明呈现低且恒定电阻。当恒定电压处于I-V线性区域时,输出电流强度不随时间而改变。然而,当恒定电压处于非线性区域时,电流强度以指数级下降后随时间而趋平。在恒电流测试下,电压仅在电流强度处于非线性区时增加。依赖时间的导电性能可通过短路来理解。短路发生在非线性区域的碳纳米管纱中炽热部位,会导致热性能降低。通过热图像、热重分析、扫描电镜和能谱分析等手段对碳纳米管纱进行分析。

Planning for LVC Simulation Experiments

The use of Live, Virtual and Constructive (LVC) simulations are increasingly being examined for potential analytical use particularly in test and evaluation. In addition to system-focused tests, LVC simulations provide a mechanism for conducting joint mission testing and system of systems testing when fiscal and resource limitations prevent the accumulation of the necessary density and diversity of assets required for these complex and comprehensive tests. LVC simulations consist of a set of entities that interact with each other within a situated environment (i.e., world) each of which is represented by a mixture of computer-based models, real people and real physical assets. The physical assets often consist of geographically dispersed test assets which are interconnected by persistent networks and augmented by virtual and constructive entities to create the joint test environment under evaluation. LVC experiments are generally not statistically designed, but really should be. Experimental design methods are discussed followed by additional design considerations when planning experiments for LVC. Some useful experimental designs are proposed and a case study is presented to illustrate the benefits of using statistical experimental design methods for LVC experiments. The case study only covers the planning portion of experimental design. The results will be presented in a subsequent paper.

James Salter＇s Pilots and Wingmen, Then and Now

This essay examines the stylistic changes James Salter made when he revised his first two published novels, The Hunters （1956） and Arm of Flesh （1960）. Examination of the revised versions, The Hunters （revised, 1997） and Cassada （2000） shows that changes made in The Hunters are primarily minor stylistic changes designed to improve visual and narrative clarity, while the revisions in Arm of Flesh/Cassada are more substantial, bringing the central character into clearer focus and making the events of the novel more accessible to non-military readers.