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Aim: To assess, from a United States (US) payer's perspective, the cost-effectiveness of gels designed to separate the endometrial surfaces (intrauterine spacers) placed following intrauterine surgery. Materials and methods: A decision tree model was developed to estimate the cost-effectiveness of intrauterine spacers used to facilitate endometrial repair and prevent the formation (primary prevention) and reformation (secondary prevention) of intrauterine adhesions (IUAs) and associated pregnancy- and birth-related adverse outcomes. Event rates and costs were extrapolated from data available in the existing literature. Sensitivity analyses were conducted to corroborate the base case results. Results: In this model, using intrauterine spacers for adhesion prevention led to net cost savings for US payers of $2,905 per patient over a 3.5-year time horizon. These savings were driven by the direct benefit of preventing procedures associated with IUA formation ($2,162 net savings) and the indirect benefit of preventing pregnancy-related complications often associated with IUA formation ($3,002). These factors offset the incremental cost of intrauterine spacer use of $1,539 based on an assumed price of $1,800 and the related increase in normal deliveries of $931. Model outcomes were sensitive to the probability of preterm and normal deliveries. Budget impact analyses show overall cost savings of $19.96 per initial member within a US healthcare plan, translating to $20 million over a 5-year time horizon for a one-million-member plan. Limitations: There are no available data on the effects of intrauterine spacers or IUAs on patients' quality of life. Resultingly, the model could not evaluate patients' utility related to treatment with or without intrauterine spacers and instead focused on costs and events avoided. Conclusion: This analysis robustly demonstrated that intrauterine spacers would be cost-saving to healthcare payers, including both per-patient and per-plan member, through a reduction in IUAs and improvements to patients' pregnancy-related outcomes. PLAIN LANGUAGE SUMMARY: Every year, women in the United States (US) undergo surgery to treat intrauterine abnormalities to maintain or improve the uterus' ability to support fetal development and result in a term delivery. Despite the benefits of these procedures, damage caused to the endometrium (uterine lining) is associated with a risk of adherence of the endometrial cavity surfaces with scar tissue known as intrauterine adhesions (IUAs). Damage to the endometrium and the resulting IUAs may be associated with infertility, light or absent menstruation, pregnancy loss, and other pregnancy-related complications. Treating these conditions within the US healthcare system consumes resources and adds costs for healthcare payers (public and private insurance providers). To facilitate endometrial repair and to reduce or prevent IUAs, researchers have developed materials to place within the endometrial cavity following surgery to separate the endometrial surfaces during the early healing period. These intrauterine "spacers" are intended to improve patients' subsequent clinical outcomes and save money for healthcare payers. It is unknown whether these improved clinical outcomes offset the cost of the routine use of spacers following "at-risk" procedures that involve the endometrial cavity. We developed a model designed to determine the cost-effectiveness of an intrauterine spacer by quantifying improvements in clinical outcomes and the resultant cost savings for patients undergoing uterine surgeries with or without spacers. Our model predicted that routinely using such spacers following at-risk procedures would improve patient outcomes and reduce costs to US payers. [ABSTRACT FROM AUTHOR]

Visible light photocatalysis by semiconductor nanomaterials is one of the promising methods due to its sustainable nature and cost effectiveness. Co-doping in TiO2 by metal as well as non-metal ion is an effective way to make it an efficient visible light photocatalyst. In this work, highly competent nanostructured Ta/N-TiO2 has been standardised by following sequential trials on series of tantalum and nitrogen co-doped TiO2 and characterised by PXRD, UV-Vis-DRS, SEM-EDAX, TEM and XPS. Diffuse reflectance-UV-Vis spectroscopy (UV-Vis-DRS) of the particles revealed that optical band gaps were decreasing only up to 20 mol% of the Ta content. It was observed, the doping percentage of Ta was found to significantly control the extent of N incorporation into the particles. Sunlight stimulated photocatalytic dye degradation experiments were performed over aqueous methylene blue (MB) and the Ta/N co-doped TiO2 particles containing 20 mol% of Ta displayed the paramount photocatalytic activity. Photocatalytic disinfection also performed over E. coli, S. aureus and Bacillus employing 20 mol% of Ta/N-TiO2. Significant amount of inhibition found in E. coli and S. aureus and possible killing mechanism are discussed in 'Result and discussion' section. The co-doped TiO2 has dual advantage to act both as a visible light active photocatalyst and antibacterial agent. [ABSTRACT FROM AUTHOR]

In the present study a multi response optimization method using utility concept is proposed for electrical discharge machining (EDM) of AA 6061/10%Al2O3 AMMC. In the present study the required material is fabricated using stir casting process and characterization is done using SEM and EDX. The machining characteristics that are being investigated are material removal rate (MRR), tool wear rate (TWR), surface roughness (SR) and overcut (OC) along with surface topography of the drilled holes. Taguchi's L27 orthogonal array design is used for experimentation. The Investigation indicated that material removal rate, tool wear rate, overcut and surface roughness increases with increase in pulse-on time and peak current. But duty factor has less effect on these responses. Multi-response optimization with utility concept provides the collective optimization of both responses for improving the mean of the process. [ABSTRACT FROM AUTHOR]

WC–Co composite material is highly demanded in manufacturing industries, because of its unique properties such as excellent hardness with toughness, higher mechanical strength, and good dimensional stability. The present investigation is aimed at studying the impact of different experimental conditions (by varying cobalt content, thickness of work piece, tool profile, tool material, abrasive grit size, and power rating) on responses of interest (material removal rate and tool wear rate) in ultrasonic drilling of WC–Co composite material. The experiments have been planned by using Taguchi's L-36 orthogonal array and grey relation analysis has been applied for optimization of multiple responses. Analysis of variance is also employed to find the significant factors. Significant effects are observed for process variables such as cobalt content, abrasive grain size, and power level. Tools with higher hardness delivered better machining performance. [ABSTRACT FROM PUBLISHER]

In this work, quantitative assessment of surface damage in terms of parameters like surface crack density and recast layer thickness in wire electrical discharge machining (WEDM) process has been undertaken. The effect of processing conditions on crack formation is studied using scanning electron microscope. Surface crack density and recast layer thickness analysis in terms of machining parameters such as pulse on time, pulse off time, peak current, spark gap voltage significantly deteriorate the microstructure of machined samples, which produces the deeper, wider overlapping craters, pockmarks, globules of debris andmicro cracks. The microstructure analysis ofWEDMsurface was based upon the theory of electrical discharge phase and metallurgical physics. It is found that the pulse on time, pulse off time and peak current are the most dominating parameters for both surface crack density and recast layer thickness. [ABSTRACT FROM AUTHOR]

This paper presents the experimental investigation on tool wear rate (TWR) in powder-mixed electrical discharge machining (PMEDM) of aluminum 6061 alloy reinforced with 10% silicon carbide particles (AA6061/10%SiCpcomposite). Composite material is fabricated by mechanical stir casting process and further characterized by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Tungsten powder with concentration of 4 g/L is mixed in the dielectric fluid. To know the influence of powder suspension in dielectric fluid on TWR, comparative study is done on the basis of experiments performed using basic EDM and PMEDM process. Experiments have been designed as per central composite rotatable design (CCRD) using response surface methodology (RSM) approach. Four process parameters, namely, peak current, pulse-on time, pulse-off time, and gap voltage have been considered for TWR investigation. Individual and interactive influence of various parameters on TWR is explained with the help of analysis of variance and three-dimensional graphs. Using RSM approach, results have been further optimized. PMEDM approach provides 51.12% reduction in TWR for machining of AA6061/10%SiCpcomposite. [ABSTRACT FROM PUBLISHER]

This study has focused on the evaluation of the influence of different input variables (cobalt content, thickness of workpiece, tool profile, tool material, size of abrasive grains, and power rating) on the hole quality (dimensional and form accuracy) obtained in ultrasonic machining of WC-Co composite material. Taguchi's approach has been employed for planning the experiments and optimization of the experimental results. Three measures of hole quality (hole oversize, out of roundness, and conicity) have been investigated under controlled experimental conditions. The experimental results showed that abrasive grit size and power rating were most influential for the hole quality. Hole quality has been found to be improved at higher cobalt content, whereas it is found to be degraded with the use of coarse grit size. [ABSTRACT FROM AUTHOR]

In the present work, aluminum alloy 6061/10%SiC composite is machined using numerical controlled Z-axis (ZNC) electrical discharge machining (EDM) process. Improvement in material removal rate (MRR) is explored using tungsten powder suspended dielectric fluid in EDM process (powder-mixed electrical discharge machining (PMEDM)). Peak current, pulse on time, pulse off time, and gap voltage are studied as process parameters. Mathematical relation between process parameters and MRR is established on basis of response surface methodology. The results obtained are further compared with MRR achieved from machining using simple EDM. The existence of tungsten particles in kerosene resulted in 48.43% improvement in MRR. The influence of tungsten powder-mixed dielectric fluid on machined surface is analyzed using scanning electron microscope and energy dispersive spectroscopy (EDS). The results revealed improvement in surface finish and reduction in recast layer thickness with PMEDM. EDS analysis reported presence of tungsten and carbon in recast layer deposited on machined surface. [ABSTRACT FROM PUBLISHER]

In this study, machining of AA6061/10%SiC composite fabricated by mechanical stir casting process has been experimentally investigated using electrodischarge machining (EDM) process with tungsten-powder-mixed dielectric fluid (PMEDM). Peak current, pulse on-time, pulse off-time, and gap voltage are selected as machining parameters. Mathematical relation has been established for response quality characteristics like surface roughness with and without tungsten powder dielectric fluid using Central Composite Rotatable Design (CCRD) through response surface methodology (RSM). Surface characteristics like microhardness, surface topography, and white recast layer have been evaluated through scanning electron microscope (SEM), electrodispersive X-ray spectroscopy (EDS), and micro-Vicker hardness. Results have also been compared with simple EDM of AA6061/10%SiC composite without powder-mixed dielectric fluid. The existence of tungsten powder in dielectric fluid increases surface quality owing to decrease in number, size, and depth of craters formed while machining. Thickness of white recast layer is reduced whereas surface hardness is increased when machined with powder-mixed EDM. [ABSTRACT FROM AUTHOR]

In this study, effects of input parameters such as pulse on time (TON), pulse off time (TOFF), peak current (IP), wire feed (WF), wire tension (WT) and servo voltage (SV) on machining characteristics such as material removal rate (MRR), surface roughness (SR) and wire weight consumption (WWC) were investigated in wire electric discharge machining (WEDM) process using commercially pure titanium as work material. The consumption of wire and its correlation with wire wear was also investigated. The responses were optimized simultaneously using grey-fuzzy logic approach. Surface integrity aspects such as microstructure analysis (including recast layer thickness, debris and cracks, crater size and shape, etc.) of the selected machined titanium samples have also been investigated to evaluate the suitability of WEDM for machining titanium. The material transfer mechanism between the zinccoated wire electrode and the work surface has been studied using energy dispersive X-ray analysis. A mechanistic model has also been developed and validated for prediction of the response parameter (MRR) over a wide range of input variables. [ABSTRACT FROM AUTHOR]

The wire electric discharge machining process is an alternative for machining of the high strength temperature resistant materials. The present research work is mainly focused on the investigation of integrity of the work surface and wire electrode surface after machining with WEDM. Experimental results showed that pulse-on time, pulse-off time and peak current significantly affected the surface integrity with the formation of deep-wide overlapping craters, pock marks, debris, micro-cracks and recast layer. Both carbides and oxides were formed either in free form and/or in compound form due to decomposition of de-ionized water, machined samples and wire material. The compounds like titanium dioxide (rutile)(TiO2),(TiO0.325),Ti2O3, Ilmenite(Fe2Ti4O), titanium carbides(TiC)and copper titanium dioxide(Cu3TiO4)were formed due to phase transformations that were analyzed through X-ray diffraction and energy dispersive X-ray method. The effect of process parameters on the wear of wire surface has also been considered. [ABSTRACT FROM AUTHOR]

Ultrasonic machining (USM) is a mechanical material removal process used to erode holes and cavities in hard or brittle workpieces by using shaped tools, high-frequency mechanical motion, and an abrasive slurry. The fundamental principles of stationary ultrasonic machining, the material removal mechanisms involved, proposed models for estimation of machining rate, the effect of operating parameters on material removal rate, tool wear rate, and workpiece surface finish, research work reported on rotary mode USM, hybrid USM, process capabilities of USM have been extensively reviewed in this article. The limitations of USM, gaps observed from the literature review, and the directions for future research have also been presented. Overall, this article presents a comprehensive review of USM process for advancement of the process through fundamental insights into the process. [ABSTRACT FROM PUBLISHER]