Miracle-dz/UniFAR-FTUs huggingface dataset:
Multi-physics modeling of plasma discharge and material removal in micro electro-discharge machining process

Micro electro-discharge machining (micro-EDM) is a machining process capable of removing material in sub-grain size range and machining a range of materials irrespective of their hardness. Due to the unique capabilities offered by micro-EDM process in manufacturing high accuracy micro-scale parts with complex geometries, it has potential to meet wide spectrum of current and future needs in the electronics, automotive, optics and bio-medical industries. Despite these advantages, one of the major disadvantages of the micro-EDM process has been its low productivity in terms of material removal rate (MRR). To improve the MRR, the micro-EDM process has been subjected to numerous parametric optimization studies. However, machining characteristics of the micro-EDM process are influenced by a large number of controllable process parameters. This makes it very cumbersome to conduct full-scale parametric studies and find optimum machining parameters without understanding of material removal mechanism. Therefore, there is a strong need for development of a physics-based model to gain fundamental knowledge of the micro-EDM process. In this research work, a multi-physics model of the micro-EDM process has been developed to understand formation and expansion of micro-EDM plasma, and the process of formation of melt-pool and material removal at the workpiece. Initially, a model of micro-EDM plasma has been developed using a ’Global Model’ approach in which the plasma is assumed to be spatially uniform, and equations of mass and energy conservation are solved simultaneously along with the dynamics of the plasma bubble growth. One of the unique features of this model is the plasma chemistry module that enables understanding of chemical as well as energy interactions of various species in the plasma. Using the micro-EDM plasma model, complete temporal description of the micro-EDM plasma is obtained in terms of the composition of the plasma, temperature of electrons and other species, radius of the plasma bubble, the plasma pressure and heat flux to the electrodes. The model is also used to study the effect of electric field in the inter-electrode gap and the gap distance on the plasma characteristics. The model predicts that the application of higher field at a fixed gap increases the electron density, plasma temperature, plasma radius, plasma pressure and the heat flux to the workpiece, while increasing gap distance for a fixed electric field results in decreased overall plasma density and increased heat flux. The micro-EDM plasma model is further enhanced to predict time-transient electrical characteristics of a micro-EDM discharge such as plasma resistance, voltage, current and discharge energy. In micro-EDM,
Operation and reconstruction of signals based on integrate-and-fire conversion using FPGA

Neurons are diverse in terms of functionality and behaviour; however a family of them can be modeled as an electrical circuit aggregating input currents from neighboring neurons. Integration-and-Fire Neuron (IFN) is a simplified view of a neuron operation that reduces the model to a first order fire-and-reset system. IFN can be used as a modulation technique to transmit data in a very efficient way. It is also possible to perform some signal operations in the IFN space, just looking into the time space in-between IFN spikes, and there are several approaches to reconstruct back the analog signal, at the receiver side, either in time-domain or frequency-domain. After the analysis of the different methods for signal reconstruction based on IFN modulation technique, and also after surveying different methods of doing mathematical operations in the IFN space, the main goal of the thesis is then to synthesize, on an FPGA, the fundamental mathematical operations over the spike based signals, together with a reconstruction method that will convert the IFN signal back to a magnitude/time signal, with a reasonable bit resolution.
Social exclusion and substance use among African immigrants: The role of discrimination

ABSTRACT Due to their racialized identity and immigrant status, African immigrants face increased risk for social exclusion and other negative outcomes. Research indicates that discrimination, social and economic disadvantage increase risk for substance use among Black populations in the United States. While emerging studies on African immigrants have explored consequences of social exclusion on psychological health, little is known about how these conditions impact substance use patterns. This study examined the effects of social exclusion on alcohol and/or other drug use, and non-medical use of prescription drugs among African immigrants, and explored whether perceived discrimination mediated this relationship. Data were collected between 2019 and 2020 from a cross-sectional survey examining experiences of first and second-generation African immigrants across the United States (N = 597). The majority of the sample identified as female (71%) and Black (82%). Structural equation modeling was conducted with probit regression paths to examine the direct and indirect effects of three dimensions of social exclusion (sociocultural, economic, and structural) on alcohol and/or other drug use and non-medical use of prescription drugs, with perceived discrimination as the mediator. Increased sociocultural and structural exclusion significantly increased the likelihood of alcohol and/or other drug use and non-medical use of prescription drugs through the perceived discrimination pathway. Structural exclusion also had direct effects on substance use. Findings highlight the importance of examining social stressors when exploring risk for substance use, and point to the need for prevention efforts that reduce negative attitudes and promote inclusivity of this marginalized population.
Using the Health Belief Model to Identify Predictors of COVID-19 Vaccine Acceptance among a Sample of Pregnant Women in the U.S.: A Cross-Sectional Survey

The aim of the study was to identify factors that predict acceptance of the COVID-19 vaccine among pregnant women. Using the Health Belief Model, the authors administered a cross-sectional survey of pregnant and postpartum women in the United States during the COVID-19 pandemic. Overall, 227 women agreed to participate and completed the entire survey. Over half (59%) the participants had received the COVID-19 vaccine at the time of the study. Perceived barriers to vaccination (p < 0.001) and perceived benefits (p < 0.001) to vaccination were statistically significant predictors of vaccination. Trust in healthcare providers was also statistically predictive of vaccination (p = 0.001). Binary regression results were statistically significant (χ2(9) = 79.90, p < 0.001), suggesting that perceived benefits, barriers, severity, and susceptibility scores had a statistically significant effect on the odds of a participant being vaccinated. Results indicate a need for increased patient education regarding COVID-19 vaccination during pregnancy, including the benefits of vaccination for mother and fetus.
Community of Inquiry Analysis of Alignment between Instructors’ Intentions and Students’ Perceptions in Online Courses

According to the Community of Inquiry model, the online learning experience is optimized when instructors properly address three critical components throughout their teaching: teaching presence (TP), social presence (SP), and cognitive presence (CP). Considering these constructs, this study investigated the following questions: (a) What are instructors’ intentions? (b) What are students’ perceptions? and (c) What is the alignment between the instructor’s intentions and the students’ perceptions? Four instructors teaching five online courses with 44 students completed the CoI surveys. Results indicated that TP received the highest score among instructors (M = 4.05, SD = 0.32) and students (M = 4.01, SD = 0.65) whereas SP was the lowest among instructors (M = 2.64, SD = 0.69) and students (M = 3.60, SD = 0.59). Results also identified two courses with weaker alignments than the other courses. A discussion regarding the variations between traditional and distance learning from a different has merit. If enhancing the distance learning experience is a priority, online instructors should create effective social presence opportunities within their courses.
THE EFFECT OF COMPANY PERFORMANCE ON FIRM VALUE WITH INSTITUTIONAL OWNERSHIP AS AN INTERVENING VARIABLE (AN EMPIRICAL STUDY ON REAL ESTATE AND PROPERTY COMPANIES REGISTERED IN INDONESIAN STOCK EXCHANGE 2016-2019)

The aims of this research is to analyze the impact of Current Ratio and ROA on Company Value with Institutional Ownership as an intervening variable with Empirical Studies on property and real estate companies registered on the IDX in 2016 – 2019.This study used quantitative descriptive method, where the data is measured on a numerical scale with the secondary data,. This study result is Institutional Ownership had not affected significantly by Current Ratio with a t-statistic of 0.883318 and firm value also not significantly affected by CR with a t-statistic of -0.712988, while Institutional Ownership not affected significantly by ROA rwith a t-statistic of 0.303315, but ROA affected significantly by ROA with a t-statistic of 3.088025 and institutional ownership not impacted significantly on firm value with a t-statistic of -0.651118. Also, Current Ratio and ROA simultaneously non affect on Institutional Ownership, but simultaneously there is a significant impact of Institutional Ownership, ROA, and Current Ratio, firm value. Based on the intervening test, can be say that institutional ownership is not able to mediate the impact of CR and ROA on company value.
Optical and electrical characteristics of vertical-cavity surface-emitting lasers for free space optical communications

Among the number of optical sources, vertical-cavity surface-emitting lasers (VCSELs) are relatively recent type of semiconductor laser devices, which are attractive for a number of applications particularly for free space optical (FSO) communication systems. In such systems reliable optical devices with lower power consumption and low cost are among the key requirements. VCSELs typically operate with unstable output polarization modes, and there is a need to improve their output power regarding to the polarization instability, particularly when introducing the optical feedback (OF). This thesis investigates a number of key properties of VCSEL including the polarization instability, hysteresis loop (HL), relative intensity noise (RIN) and how to control the polarization switching (PS). The investigations are based on the analytical studies and extensive experimental work. PS properties of VCSEL are investigated by introducing variable polarization optical feedback (VPOF) with the modulation frequency and modulation depth. The dependency conditions for the HL, RIN and PS are determined with VPOF. Under OF, the threshold current (Ith) of VCSEL is reduced by 11.5% and the PS, which is demonstrated theoretically and experimentally, is completely suppressed. The PS positions are depending on the polarization angle of OF, OF levels and the bias current. The PS disappeared with the modulation depth of 78.66%, whereas it is entirely vanished with the modulation frequency of 200 MHz. The hysteresis width of the VCSEL polarization modes is reduced by increasing the feedback level. The minimum RIN value of -156 dB/Hz is achieved at a zero degree of the polarization angle for the dominant polarization mode of VCSEL under VPOF. For the first time, a novel technique based on employing orthogonal polarization OF is proposed to supress the nonlinearity associated with the modulated VCSEL, where the second, third, and fourth harmonics are completely suppressed to the noise floor. Finally, optimal operating conditions for a high-quality polarization-resolved chaos synchronization of the polarization modes of VCSEL with VPOF are experimentally and theoretically studied. A perfect value of 99% of the correlation dynamics for the chaotic synchronization of the polarization modes of VCSEL is found with a zero time delay over a wide range of polarization angle. Finally, Simulink and Origin software version 6.1 are used in this work to simulate and plot the results. The simulation results are agreed with the experimental results, which show that the chaotic synchronization dynamic of the polarization modes can be achieved by VPOF.
Design and Preparation of Avermectin Nanopesticide for Control and Prevention of Pine Wilt Disease

Pine wilt disease is a devastating forest disaster caused by Bursaphelenchus xylophilus, which has brought inestimable economic losses to the world’s forestry due to lack of effective prevention and control measures. In this paper, a porous structure CuBTC was designed to deliver avermectin (AM) and a control vector insect Japanese pine sawyer (JPS) of B. xylophilus, which can improve the biocompatibility, anti-photolysis and delivery efficacy of AM. The results illustrated the cumulative release of pH-dependent AM@CuBTC was up to 12 days (91.9%), and also effectively avoided photodegradation (pH 9.0, 120 h, retention 69.4%). From the traceable monitoring experiment, the AM@CuBTC easily penetrated the body wall of the JPS larvae and was transmitted to tissue cells though contact and diffusion. Furthermore, AM@CuBTC can effectively enhance the cytotoxicity and utilization of AM, which provides valuable research value for the application of typical plant-derived nerve agents in the prevention and control of forestry pests. AM@CuBTC as an environmentally friendly nanopesticide can efficiently deliver AM to the larval intestines where it is absorbed by the larvae. AM@CuBTC can be transmitted to the epidemic wood and dead wood at a low concentration (10 mg/L).
The effects of tropospheric ozone on plant species: New perspectives

The effect of tropospheric ozone on the physiology of plants has been well established using physicochemical analysis and visual assessment. One of the main metabolic processes, in plants that is affected by ozone, is photosynthesis. This in turn affects a number of secondary processes required for the survival of plants. This study focused on two main aspects; the qualitative determination of damage through visual assessment and the quantification of damage through the determination of the content of chlorophyll and other quality parameters using spectrophotometric techniques in a number of plant species. Three distinct setups were considered, mainly rural, urban and semiurban, representing the topography of the islands of Malta and Gozo. It was observed that chlorosis was not the sole factor contributing to the yellowing of the leaves. Another important finding was the correlation between ozone levels (50.18-69.35 ppb) and the anthocyanin content (2.57-28.99 mg/kg) of leaves. From the three plant species that were extensively studied (Nerium oleander, Pinus halepensis and Schinus terebinthifolius), the N. oleander exhibited promising results as a bioindicator for ozone-induced damage. Due to the presence of this ornamental plant in rural and urban areas, it can be used by researchers and authorities as a tool for assessment of tropospheric ozone levels.
Culture of Healthy Eating and Food Environments, Policies, and Practices in Regional New Zealand Schools

The school food environment plays an important role in shaping students’ dietary choices, which often influence future dietary behaviours. We surveyed primary and secondary schools in Hawke’s Bay, New Zealand, to measure the comprehensiveness and strength of food policies, describe the culture of food provision, and identify barriers to improving school food environments. Fifty-one schools were included in the final analysis, with 58.8% having a food policy, most of which used a generic template. Schools with food policies and those participating in the free and healthy lunch programme were more likely to have a strong culture around healthy eating. Common barriers to healthy eating were food outlets near school and resistance from students. Secondary schools reported facing more barriers to implementing healthy eating cultures, were more likely to use food as classroom rewards and to sell food to students, most of which was unhealthy. Hawke’s Bay schools participating in food provision programmes are successfully improving their food environments through improved culture and delivery of healthy food; however, more action is needed to strengthen the wording and guidance in food policies and reduce the provision of unhealthy food in schools before effective change can be achieved.
VERIFICATION OF THE CROWN WALL STABILITY TAKING INTO ACCOUNT THE HYDRAULIC PERFORMANCE CURVES

The design of a breakwater requires that the failure modes which can affect its security, functionality and operationality in its useful life are bounded. The failure modes can be verified by means of the corresponding verification equation. In this work, a unified methodology to verify simultaneously the failure modes produce by wind waves in front or face of the breakwater is presented. This methodology is based on formulate the verification equations of the failure modes forced by wind waves in the front or face of the breakwater in terms of the kinematic and dynamic variables of the flow at these locations. It has been applied to analyse the failure mode that considers sliding of the crown wall. Results show that the parameters of the pdf of these variables depend on the total wave height at the same location and therefore, the verification equation can be also formulated in terms of this variable.
The Prevalence of Histopathological Features of Pneumonia in Goats with Symptomatic Caprine Arthritis-Encephalitis

Chronic interstitial pneumonia (CIP) is a main pathology of sheep infected with small ruminant lentivirus (SRLV). Caprine arthritis-encephalitis (CAE) is caused by the same pathogen; however, the presence of CIP has been only occasionally reported in SRLV-infected goats. We carried out a cross-sectional study to determine the prevalence of histopathological lesions indicative of CIP in goats with symptomatic CAE, and to investigate whether CIP was associated with a higher prevalence of other types of pneumonia (purulent bronchopneumonia, fibrinous pleuropneumonia) or bacterial infections. Lung specimens and bronchial swabs were collected for histopathological and bacteriological examination, respectively, from 116 goats from a CAE-affected herd. All goats were euthanized due to severe clinical signs of CAE. The goats were seropositive for SRLV infection in two different ELISAs and the presence of SRLV antigen in the lung tissue was confirmed by immunohistochemistry. Histopathologically, pneumonia of any type was confirmed in 82 goats (70.7%) and CIP was present in 67 goats (57.8%). In most goats, the severity of the histopathological features of pneumonia was mild. Bacteria were detected in bronchial swabs from 73 goats (62.9%). CIP proved to be significantly positively linked to the occurrence of purulent bronchopneumonia (p < 0.001), fibrinous pleuropneumonia (p = 0.001), and of the infection of lungs with bacteria capable of causing pneumonia (p = 0.050). The causal character of these associations should be considered and warrants further investigation.
Evidence-Based Application of Acupuncture for Pain Management in Companion Animal Medicine

The use of veterinary acupuncture for pain relief is expanding among small animal practitioners. Although acupuncture was developed as part of the medical system in Ancient China, research into the scientific basis of its effects is expanding rapidly. Acupuncture is very effective for analgesia on a local, segmental, and suprasegmental level. Many forms of acupuncture can be used independently or as part of a balanced multi-modal approach for the control of acute and chronic pain. In the hands of a skilled practitioner, acupuncture can be a safe and effective modality for treating pain in companion animals. This article outlines the mechanisms of action of acupuncture, its related neurophysiology and provides examples from the literature demonstrating its effectiveness.
E-portfolios in teaching, learning and assessment: tensions in theory and praxis

ABSTRACT E-portfolios are increasingly used in innovative ways, particularly in higher education, where they have the potential to transform teaching, learning and assessment. Given that students are learning in a hypertextual, digitalised and multimedia world, there is an ever-pressing need for assessment to be more authentic, engaging, and to develop transversal skills. This research analysed the challenges and opportunities of e-portfolios in secondary schools and universities. A review of the literature was undertaken in which studies conducted primarily across Europe and the US over the last 20 years were evaluated. Analysis identified several tensions relating to e-portfolio theory and praxis which were organised according to three main themes: the theory and research underpinning e-portfolios; the uses and purposes of e-portfolios; and the challenges and opportunities related to e-portfolio implementation. These tensions both deepen our understanding of e-portfolios as pedagogical tools as well as inform internationally relevant recommendations for implementation.
Comparison of Testing Designs for Flexural Strength of 3Y-TZP and 5Y-PSZ Considering Different Surface Treatment

The aim of this study was to analyze the influence of different surface treatments and the corresponding surface roughness on the ball-on-three-balls test and piston-on-three-balls test for measuring flexural strength 3Y-TZP and 5Y-PSZ. Additionally, the influence of cutting the material into the specimens when pre-sintered or fully sintered was analyzed. A total of 120 specimens for each material group, 3Y-TZP zirconia (Katana HT, Kuraray) and the 4 different layers of multilayered 5Y-PSZ zirconia (Katana UTML, Kuraray), were produced. The used material was cut into half of the specimens in a fully sintered stage, the other half was cut when pre-sintered. Each subgroup was divided into 3 different surface treatment groups being air abraded with 50 µm alumina particles at 1 bar pressure, ground with 600 SiC paper or polished up to 1 µm with a polycristalline diamond suspension. These were then analyzed by X-ray diffraction (XRD) (N = 3) and tested for flexural strength using the ball-on-three-balls test (N = 10) or piston-on-three-balls test (N = 10). For 3Y-TZP groups different surface roughness did not result in statistically significant differences in flexural strength but cutting the specimens in fully sintered state significantly reduced flexural strength of 1133 ± 109 to 741 ± 81 MPa. For 5Y-PSZ groups air abrasion of the specimens with alumina particles significantly reduced the flexural strength of 562 ± 68 MPa to 358 ± 58 MPa. Cutting and surface treatment in pre-sintered or fully sintered state had no significant influence. Flexural strength testing with the ball-on-three-balls test resulted in about 20% higher strengths compared to the piston-on-three-balls test. Results of both tests showed the same tendencies when compared.