Optimization of EDM Injection Flushing Type Control Parameters Using Grey Relational Analysis on AISI 304 Stainless Steel Workpiece

This paper deals with optimization of Electrical Discharge Machining (EDM) Injection flushing type control parameters on multi-performance optimization characteristics instead of single performance optimization using Grey Relational Analysis (GRA) Method. The experimental control parameters were being optimized according to their various machining characteristics namely material removal rate (MRR), electrode wear ratio (EWR) and surface roughness (SR) using copper as the tool and AISI 304 stainless steel as the workpiece. This parameters optimization was based on Taguchi’s orthogonal array (OA) combined with GRA. A grey relational grade (GRG) calculated based on GRA was used to optimize the EDM process with multiple performance characteristics and Taguchi’s L18 OA was used to plan the experiments. The machining parameters selected are polarity, pulse on duration, discharge current, discharge voltage, machining depth, machining diameter and dielectric liquid pressure. Results shown that machining performance was improved effectively using this approach. The predicted responses at optimum parameter levels are in good agreement with the results of confirmation experiments conducted for verification tests

Visualizing the influence of geography, oil and geopolitics on civil wars in the Arab world: A novel application of self-organizing maps and duration models

The aim of this paper is to investigate why some internal conflicts are terminated quickly, while others linger for several decades without a looming resolution in the horizon. In an attempt to achieve this objective, the role played by geopolitical factors in the Arab world's internal conflicts was investigated. More specifically, we used Kohonen self-organizing maps, an artificial intelligence-based neural network technique, along with event duration models to investigate the role played by distance from the capital, access to international borders, terrain, valuable natural resources such as oil, and rebels fighting capability in civil wars in the Arab world. Using recently validated data spanning more than 50 years of Arab civil wars (1948–2003), our findings indicate that previously ignored geopolitical factors seem to play an important role in the duration of internal conflicts in the Arab World

Synthesis, Characterization and Application of Nano-adsorbent Materials in the Sorption of Pb(II), Ni(II), Co(II), Mn(II), Li(I) from Aqueous Solution

In this study, nano-adsorbent materials were synthesized from two different precursors by thermal activation technique. The first was the synthesizing of nano-zinc silicate from chemical reagents of zinc oxide and commercial silica gel. The second was the preparation of nano-pore size activated carbon from different biomass. The synthesized nano-adsorbent materials were characterized by different techniques; Surface Area, FTIR, XRD and SEM. The prepared nano-adsorbent materials were applied in the sorption and separation of some heavy metals from aqueous solution. These metals includes; Pb (II), Ni(II), Co(II), Mn(II) and Li(I). Some factors affecting on the sorption process (e.g. contact time and pH) were investigated. It was found that: the nano-zinc silicate (of ratio 1:1 thermally treated at 700 0C) and nano-pores activated carbon (prepared from saw dust impregnated with 70% H3PO4 overnight, then heated to 500 0C in presence of steam for 80 min.) were the best samples for sorption and separation of concerned heavy metals

Public Knowledge of Oral Cancer and Modelling of Demographic Background Factors Affecting this Knowledge in Khartoum State, Sudan

Objectives: Knowledge of oral cancer affects early detection and diagnosis of this disease. This study aimed to assess the current level of public knowledge of oral cancer in Khartoum State, Sudan, and examine how demographic background factors affect this knowledge. Methods: This cross-sectional study involved 501 participants recruited by systematic random sampling from the outpatient records of three major hospitals in Khartoum State between November 2012 and February 2013. A pretested structured questionnaire was designed to measure knowledge levels. A logistic regression model was utilised with demographic background variables as independent variables and knowledge of oral cancer as the dependent variable. A path analysis was conducted to build a structural model. Results: Of the 501 participants, 42.5% had no knowledge of oral cancer, while 5.4%, 39.9% and 12.2% had low, moderate and high knowledge levels, respectively. Logistic regression modelling showed that age, place of residence and education levels were significantly associated with knowledge levels (P = 0.009, 0.017 and <0.001, respectively). According to the structural model, age and place of residence had a prominent direct effect on knowledge, while age and residence also had a prominent indirect effect mediated through education levels. Conclusion: Education levels had the most prominent positive effect on knowledge of oral cancer among outpatients at major hospitals in Khartoum State. Moreover, education levels were found to mediate the effect of other background variables

Secrecy Performance of Decode-and-Forward Based Hybrid RF/VLC Relaying Systems

https://ieeexplore.ieee.org/document/8606043In this paper, we consider the secrecy of a hybrid radio frequency (RF)/visible light communication (VLC) system equipped with decode-and-forward relaying. We develop physical layer security algorithms that mitigate eavesdropping on both RF and VLC networks based on zero-forcing beamforming techniques. We evaluate the system performance in terms of secrecy capacity (SC) and outage probability (OP) for two network scenarios, namely non-cooperative (NCPS) and cooperative power saving (CPS) models. The NCPS case assumes fixed power at both source and relay while the CPS case assumes total average power shared between the source and relay. Our objective is to find the minimum power that satisfies a specific SC for both cases. Our simulation results show that CPS policy achieves higher SC and maintain lower OP compared with the NCPS one for the same amount of power. We also show that, for both cases, the hybrid RF/VLC network can improve SC compared with standalone RF or VLC networks

A preliminary microbiological assessment of process hygiene of traditional outdoor camel slaughter in Sahrawi refugee camps.

The aim of this study was to investigate the hygiene performance of a camel (Camelus dromedarius) slaughtering process as carried out with the traditional method in the Sahrawi refugee camps located in southwestern Algeria. The camel slaughtering process in this region differs significantly from that carried out in commercial abattoirs. Slaughtering is performed outdoors in desert areas, and dehiding of the carcass is approached via the dorsoventral route rather than the classic ventrodorsal route. Samples were taken from 10 camel carcasses from three different areas: the hide, the carcass meat immediately after dehiding, and the meat after final cutting. Enterobacteriaceae counts (EC) were enumerated employing conventional laboratory techniques. Carcass meat samples resulted in EC below the detection limit more frequently if the hide samples from the same carcass had also EC counts below the detection limit. Because of the low number of trials, the calculation of statistical significance of the results was not possible. Further experimental research is needed in order to validate the results presented in this study. The comparison of the microbiological hygiene performance between dorsal dehiding and traditional ventral dehiding of slaughtered animals could serve to validate the hypothesis of the potential positive impact of the dorsal dehiding method in carcass meat hygiene

Intraoperative endomanometric laparoscopic Nissen fundoplication improves postoperative outcomes in large sliding hiatus hernia with severe gastroesophageal reflux disease. A retrospective cohort study

Background: Laparoscopic Nissen Fundoplication (LNF) is the gold standard surgical intervention for gastroesophageal reflux disease (GERD). LNF can be followed by recurrent symptoms or complications affecting patient satisfaction. The aim of this study is to assess the value of the intraoperative endomanometric evaluation of esophagogastric competence and pressure combined with LNF in patients with large sliding hiatus hernia (> 5 cm) with severe GERD (DeMeester score >100). Materials and methods: This is a retrospective, multicenter cohort study. Baseline characteristics, postoperative dysphagia and gas bloat syndrome, recurrent symptoms, and satisfaction were collected from a prospectively maintained database. Outcomes analyzed included recurrent reflux symptoms, postoperative side effects, and satisfaction with surgery. Results: 360 patients were stratified into endomanometric LNF (180 patients, LNF+) and LNF alone (180 patients, LNF). Recurrent heartburn (3.9% vs. 8.3%) and recurrent regurgitation (2.2% vs. 5%) showed a lower incidence in the LNF+ group (P=0.012). Postoperative score III recurrent heartburn and score III regurgitations occurred in 0% vs. 3.3% and 0% vs. 2.8% cases in the LNF+ and LNF groups, respectively (P=0.005). Postoperative persistent dysphagia and gas bloat syndrome occurred in 1.75% vs. 5.6% and 0% vs. 3.9% of patients (P=0.001). Score III postoperative persistent dysphagia was 0% vs. 2.8% in the two groups (P=0.007). There was no redo surgery for dysphagia after LNF+. Patient satisfaction at the end of the study was 93.3% vs. 86.7% in both cohorts, respectively (P=0.05). Conclusions: Intraoperative high-resolution manometry (HRM) and endoscopic were feasible in all patients, and the outcomes were favorable from an effectiveness and safety standpoint

Ramadan Observance Is Associated with Impaired Kung-Fu-Specific Decision-Making Skills

The aim of the present study is to evaluate the effect of Ramadan observance (RAM) on decision-making in Kung-Fu athletes. Fourteen male Kung-Fu athletes (mean age = 19 ± 3 years) completed two test sessions: before Ramadan (BR) and at the end of Ramadan (ER). In the afternoon of each session (between 16:00 h and 18:00 h), participants completed: Epworth Sleepiness Scale (ESS), Profile of Mood States (POMS), and Pittsburg Sleep Quality Index (PSQI). Subjects also reported subjective fatigue, alertness, and concentration. Additionally, all participants performed video-based decision-making tasks (i.e., reaction time and decision-making). Results indicated that reaction time decreased by 30% at ER vs. BR (p p p p p < 0.05). In conclusion, Ramadan observance was associated with an adverse effect on sleep and decision making, as well as feelings of fatigue, alertness, and concentration

Design, synthesis, and biological investigation of oxadiazolyl, thiadiazolyl, and pyrimidinyl linked antipyrine derivatives as potential non-acidic anti-inflammatory agents

A novel series of 12 antipyrine derivatives containing 1,3,4-oxadiazoles (4a-d), 1,3,4-thiadiazoles (6a-d), and pyrimidines (8a-d), was preparedand assessed for its potential in&nbsp;vitro COX-2 inhibitors. Compared to Celecoxib, compounds 4b-d and 8d were the most potent derivatives c with a half-maximal inhibitory concentration range of 53-69 nM. Considering COX-2 selectivity index, compounds 4 b and 4c were chosen among these most potent derivatives for further investigation. The in&nbsp;vivo ability of compounds 4 b and 4c to counteract carrageenan-induced paw edoema has been assessed and their potential underlying mechanisms have been elucidated and the results have been further validated using molecular docking simulations