Search

The incorporation of frequency vibration into the powder mixed electric discharge machining (PMEDM) process has the potential to significantly enhance the productivity and quality of the machining process, as well as to provide a great deal of opportunities in this sector. An analysis and evaluation of the machining productivity (material removal rate [MRR]) in PMEDM with low-frequency vibration was carried out in this work by considering SKD61 as a workpiece. The oil dielectric solution mixed with titanium powder was used as a dielectric medium with red copper (Cu) as the electrode. At this point in time, the process technology parameters that have been chosen for inquiry are as follows: current (I), pulse on time (T on), powder concentration (C p), P, F, and A. The Taguchi technique (L25) was used to create the experimental matrix. With the use of analysis of variance, it was able to examine the impact that the factors had on MRR, and the analysis was utilized to ascertain the highest possible value of MRR. I was the parameter that has the most significant effect, according to the findings, whereas T on was the parameter that has the least significant effect. The maximum value of the MRRmax is equal to 31.29 mm3/min.

In this study, the effects of low-frequency vibrations on machining SKD61 steel workpiece in electrical discharge machining (EDM) with titanium powder-mixed dielectric fluid were investigated. The results showed that the vibrations incorporated into the workpiece in powder-mixed EDM (PMEDM) led to significant improvement in machining efficiency. The material removal rate had the maximum increase of 141.7% with 70.2% of lower electrode wear rate and 69.9% of lower surface roughness. Hence, it is proved that the effectiveness of vibration in PMEDM can be improved. [ABSTRACT FROM AUTHOR]

This study deals about the influence of vibrations incorporated into a workpiece during powder-mixed electrical discharge machining (PMEDM) on quality measures such as material removal rate (MRR), surface roughness (R a) and microhardness. It has been found that the low-frequency vibration incorporated into the workpiece positively affects the processing efficiency of electrical discharge machining (EDM) and PMEDM. However, the effect of low-frequency vibration in PMEDM has been better than EDM. The higher vibration frequency significantly improves the MRR and R a in PMEDM. The MRR has been improved by 95.89% and with lower R a of 63.2% in PMEDM. The hardness of the machined surface after PMEDM using titanium powder mixed in dielectric liquid was increased approximately two times as compared with conventional EDM. [ABSTRACT FROM AUTHOR]

Purpose: The overall objective of the survey was to systematically examine patients' perspectives on lower urinary tract symptoms (LUTS) and their treatment in Southeast Asia. Methods: A multinational cross-sectional survey involving adult men seeking consultation at urology outpatient clinics because of LUTS in Southeast Asia was conducted using convenience sampling. Self-reported prevalence, bother, treatment and treatment satisfaction of selected LUTS including urgency, nocturia, slow stream, and post-micturition dribble were evaluated. Results: In total, 1535 eligible patients were enrolled in the survey. A majority of respondents were aged 56-75 years, not employed, and had not undergone prostate operation before. Overall, the self-reported prevalence of nocturia was 88% (95% CI 86-90%), slow stream 61% (95% CI 59-63%), post micturition dribble 55% (95% CI 52-58%), and urgency 52% (95% CI 49-55%). There were marked differences in the country specific prevalence of LUTS complaints. Frequently, symptoms coexisted and were combined with nocturia. More than half of patients felt at least some degree of bother from their symptoms: 61% for urgency, 57% for nocturia, 58% for slow stream, and 60% for post-micturition dribble. Before seeing the present urologists, nearly half of patients have received some form of prescribed treatment and more than 80% of patients indicated they would like to receive treatment. Conclusion: Men who sought urologist care for LUTS often presented with multiple symptoms. Nocturia emerged as the most common symptom amongst the four core symptoms studied. [ABSTRACT FROM AUTHOR]

Temporal and spatial water quality data are essential to evaluate human health risks. Understanding the interlinking variations between water quality and socio-economic development is the key for integrated pollution management. In this study, we applied several multivariate approaches, including trend analysis, cluster analysis, and principal component analysis, to a 15-year dataset of water quality monitoring (1999 to 2013) in the Thi Vai estuary, Southern Vietnam. We discovered a rapid improvement for most of the considered water quality parameters (e.g., DO, NH4, and BOD) by step trend analysis, after the pollution abatement in 2008. Nevertheless, the nitrate concentration increased significantly at the upper and middle parts and decreased at the lower part of the estuary. Principal component (PC) analysis indicates that nowadays the water quality of the Thi Vai is influenced by point and diffuse pollution. The first PC represents soil erosion and stormwater loads in the catchment (TSS, PO4, and Fetotal); the second PC (DO, NO2, and NO3) determines the influence of DO on nitrification and denitrification; and the third PC (pH and NH4) determines point source pollution and dilution by seawater. Therefore, this study demonstrated the need for stricter pollution abatement strategies to restore and to manage the water quality of the Thi Vai Estuary. [ABSTRACT FROM AUTHOR]