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Introduction:During tetralogy of Fallot repair, leaving or even create an interatrial communication may facilitate post-operative course particularly with right ventricle restrictive physiology. The aim of our study is to assess the influence of atrial communication on post-operative course of tetralogy of Fallot repair.Methods:Retrospectively, we studied all children who had tetralogy of Fallot repair (2003–2018). We divided them into two groups: tetralogy of Fallot repair with interatrial communication (TOFASD) group and tetralogy of Fallot repair with intact atrial septum (TOFIAS) group. We performed propensity match score for specific pre- or intra-operative variables and compared groups for post-operative outcome variables. Secondarily, we looked for right ventricle restrictive physiology incidence and influence of early repair performed before 3 months of age on post-operative course.Results:One hundred and sixty children underwent tetralogy of Fallot repair including (93) cases of TOFIAS (58%) and (67) cases of TOFASD (42%). With propensity matching score, 52 patients from each group were compared. Post-operative course was indifferent in term of positive pressure ventilation time, vasoactive inotropic score, creatinine and lactic acid levels, duration and amount of chest drainage and length of intensive care unit and hospital stay. Right ventricle restrictive physiology occurred in 38% of patients with no effects on outcome. 12/104 patients (12%) with early repair needed longer pressure ventilation time (p = 0.003) and intensive care unit stay (p = 0.02).Conclusion:Leaving interatrial communication in tetralogy of Fallot repair did not affect post-operative course. As well, right ventricle restrictive physiology did not affect post-operative course. Infants undergoing early tetralogy of Fallot repair may require longer duration of positive pressure ventilation time and intensive care unit stay.

A V-bending experimental setup has been designed, to analyze the impact of blank geometry and process parameters over the springback in hot-rolled high-tensile-strength sheet metals (JSH590 steel). In this setup, a hydraulic press having the ability to vary load and holding time has been used. JSH590 sheet-metal blanks with varying geometric parameters are bend to acute, right and obtuse angles. Springback in each blank is determined which is found to be varying due to the different combinations of blank geometry and process parameters. To analyze the significance of thickness, width, bend angle, applied load and holding time, analysis of variance is applied, regression model is also derived relating the parameters with the springback, and finally, Genetic Algorithm has been applied to optimize the process parameters for the minimum springback. The outcomes of the research can be used in the industry, to evaluate the outcome in very-high-tensile-strength steel sheets.

To gain the competitive advantage, it has become essential for manufacturing industry to use its resources effectively, efficiently and economically. It is required to understand that such resources are based on 5 Ms (manpower, methods, materials, money, and machinery). In this study an apparel industry was selected to create a directorial plan by using the ideologies of resource management to improve the process efficiency. For this the data related to the product layout, operation plan, and process flow was collected. Time motion study was performed for aspect analysis. Information regarding operation, number of machines and efficiency of the production line was evaluated. The proposed plan successfully increase the efficiency up to 10%. It also shows an improvement in effective utilization of manpower and money.

The main purpose of this research is to examine the outcomes of process parameters of Wire Electro-discharge Machining over the tapered workpieces of Titanium Alloy (Ti6Al-4V). Taper angle, current and pulse-off time are considered as the controllable factors effecting the response variables. Each sample has been cut with varying sets of machine controllable parameters to assess their effect on response variables; kerf width, wire wear, Material Removal Rate and surface roughness. Analysis of variances is applied, and mean Reponses are determined to recognize and compare the most influencing parameters over the response variables for the WEDM Process. Regression model for the response variables are also developed using which optimized WEDM process parameters are determined for the optimal response variables. It can be concluded that varying thickness of materials due to tapered cross section affects all the four-response variable, while, current and pulse-off time along with their interactions have high impact over the response variables.

Surface structuring is a recognised technique to improve frictional properties of interfering surfaces. A sufficient number of studies have confirmed the successful application of structuring on mechanical seals, golf balls, engine cylinder, sliding bearings, hard disk drives, etc. Lately, structuring is applied to metal cutting tools. This study identifies the information regarding the manufacturing process with the vision to improve the machining performance. For this, a comparative analysis of friction and dry sliding wear behaviour of structured and unstructured tungsten cemented carbide was assessed. Tests were performed at different sliding speed at the constant normal load of 40 N. Results show that structuring carbide can improve friction and wear performance by 23%. Also, structuring can decreased the coefficient of friction by 7%. Energy-dispersive X-ray analysis was conducted to quantify elements concentration. Microhardness tests were performed and results revealed the improvement in hardness of structured carbide. The case study confirms that structuring cutting tools can effectively elevate machining performance and improve environmental sustainability. This research is noteworthy for tool manufactures, engineering component/ machine designers and biomedical engineers, as it highlights the comprehensive understanding of structuring carbide.

An increasing number of elderly people in recent years have raised the issue of disability/dependency. The common cause of disability/dependency in elderly people is musculoskeletal pain and related indications (Urwin, Symmons et al. 1998). Therefore, Musculoskeletal disorders (MSDs) has become worldwide dilemma (Sanders 1997). The risk of MSDs occurs both within and outside the work environment where it is being performed (Hedge, Rudakewych et al. 2002). If MSDs risk is identified at an early stage of life, then it might help people to manage the MSDs risks in performing daily tasks before it can interfere in their life and make them dependent on others. Also early management of person’s own risk can help the healthcare professionals to helps people in the society to maintain their independence in later life and reduced the social care cost burden on community. The main objective of this study is to address the known statement that there is an increased risk in later life of injury which is associated with loss of independence. Therefore, this study evaluates a person’s risk of having MSDs through performing domestic tasks. And thus with a greater understanding of that risk put in place an assessment methodology with the aim of increasing independence by decreasing or managing risks related to bad postures associated with the performance of domestic tasks. A survey was conducted to identify the hardest tasks, to be performed in home environment. A newly developed tool called “task assessment tool for ease and risk (TAER)”(Zaheer, Yoxall et al. 2018) is used to identify associated risk involved. Survey result showed that top three main task, numerous people struggle with, are general housekeeping (mopping), laundry and food cooking. It was found that TEAR analysed results were in accordance with the survey results. It is concluded from the study that, TEAR analysed results were in accordance with the survey results and people were struggling with three main task, that are general housekeeping (mopping), laundry and food cooking. Also, TAER can easily distinguish between those tasks which help the individual to take heed of the way in which he or she is performing the tasks. Also conclude that, if this tool (TAER) provide to general people in the community through healthcare services, will enable people to know their risks in performing domestic tasks and maintain their independence by acting upon the recommendation provided, which results in decrease in the likelihood of disability/dependency and stay in their own home as long as possible.

Metal cutting operations involve intense heat generation owing to plastic deformation of the work piece and due to friction at the tool-work piece and tool-chip interface. The heat generated in metal cutting unfavourably affects the quality and thus the functional performance of the product. It is known that quality and functional performance is the function of roughness and dimensional accuracy. To maintain a longer component life, along with the robust material choice, a component should have good surface finish and dimensional accuracy. While, for the organization to monitor and control their environmental issues in a holistic manner, emphasis in adopting eco-friendly practices and protecting environment has been growing continuously across all the business sectors. In this study, an attempt is made to optimize the process parameter of stainless steel AISI-410 alloy, a nuclear graded material, for better surface finish. For this, Taguchi L9 orthogonal array was utilise to identify the process parameter and cutting environment. Analysis of variance (ANOVA) was also conducted to highlight the significant parameter that affects the surface finish most. A statistical model to forecast the surface roughness was also developed and was validated by an experiment with a maximum error of 12%. Results indicates that feed rate is the most critical factor that effects the surface roughness with the contribution of 91.5%, followed by environment with 5.22% contribution, cutting speed and depth of cut with 2.7 % and 0.4 % respectively. The correlation coefficient of 0.9213 and conformation tests reveals that developed statistical model predicts surface roughness with the statistical error limit.

Springback in hot-rolled, high tensile strength sheet-metals (JSH440) are measured to evaluate the influence of blank geometry and process parameters over the springback outcomes. Sheet-metal thickness, width, bend angle, applied load and holding time are considered as controllable factors, whereas, other factors are kept constant. Analysis of Variance (ANOVA) and sensitivity analysis Are applied to observe the significance of controllable factors over the springback magnitude. Analytical models considering all the controllable parameters have been developed to predict the springback in JSH440 sheet-metals, whereas, simplified analytical models based on bend angles are also developed for different geometries of sheet-metals. Finally, the Genetic Algorithm has been applied for the determination of optimal applied load and holding times are determined for the minimum springback in different geometries of the JSH440 steel-sheets. This research can be used in the industry to predict the springback, optimize the blank geometries and process parameters for the minimum springback in JSH440 sheet-metals.

Sheet metal bending is a typical operation and springback is an unintended consequence of this operation. Since it causes fitting issues in the assembly, which leads to quality problems, anticipating it long before the bending operation is done is essential in today's production, so that machining parameters can be adjusted accordingly. In order to predict springback with minimum errors, this paper presents the idea for the development of machine learning models using tree-based learning algorithms (A class of machine learning algorithms). Tree-based learning algorithms are employed because they are precise, consistent, and easy to understand. Experimental studies provided the data for training and testing the models. The model's input parameters were sheet Material, Thickness, Width, Initial Angle (Desired angle), and Machine used to perform the bending. Following the training and testing of different tree-based learning algorithms, the results were evaluated using MAE and MSE. It was determined that Gradient boosting algorithms (a class of tree-based learning) gave the best results. Later on further evaluation of algorithms, it was found that LightGBM produced the best results, with MAE and MSE of 0.41 and 0.25, respectively.

Non-traditional machining processes are popular for generating complex features on the work piece. With advances in material engineering, new ways of cutting technologies has been emerged. However, EDM (Electric Discharge Machining) has gained recognition for producing extraordinary surface finished, intricate part geometries with accuracy and its ability to cut through difficult to machined materials. However, like every product cycle, manufacturing processes also require energy to convert raw materials into finished product. In manufacturing operations, energy input gives carbon footprints which have an effect on our environment. It is observed that reducing energy consumption is becoming the main concern of manufacturers because of enforcing environmental laws and due to the economics of the processing. It is argued that world’s 70% of energy consumption is consumed by manufacturing sector. The aim of the work was to identify direct energy demands in wire cut EDM. The variability in energy demand was explored by operating wire cut EDM at no-load and loaded conditions.Stainless steel S304 was used as a work piece. Experiments were performed on three different wire-cut EDM.Molybdenum wire, brass wire and copper wire were used as an electrode wire and distilled water was used as a working fluid. During the experiment, electrical current was measured and the variation of power requirement was evaluated. Power required by different features of EDM was compared with the existing energy models and factors were identified that consume most of the electrical energy. Further, a comparison is made between traditional and non-traditional machining processes. This contribution will help to assess energy efficiency of EDM technology and identify priority areas for improvements. This work is also significant for machine tool designers for optimum utilization of energy,reduced environmental impact and reduced production cost of their machine tool.

One of the promising and emerging techniques used to improve the tool chip contact phenomenon is to create micro- and/or nanostructures on the surfaces of cutting tools. The rake face structuring o...

Surface structuring has been long existed to improve the tribological application. Recently, it has been applied to the cutting tools and has shown the promising results. However, no study has been yet conducted that identified the suitable shape of structures that can be meritoriously applied to the cutting tool. In this study, laser-radiated micro-structures in shape of holes and slots were created on the rake face of cutting tools. Their machining performance was observed over the range of cutting speed and compared to unstructured cutting tool. Machining factors such as cutting force, compression ratio, contact length and tool wear were selected as a criterion of performance. Wide range of orthogonal cutting experiments was performed to identify shapes of micro-structures that can bring elevated results in mechanical machining. Sticking and sliding contact characterization were executed. For the greater advantage, the assessment of machinability rating has also been taken under consideration. It was found that the end goal (better performance or reduced energy consumption) of mechanical machining process is associated with structure shape.

In this study, femtosecond laser was used to create micro-structures on the flank face of a cutting tool. For the first time, a nature-inspired design (shape) of structure was created and explored. The inspiration for the nature-inspired design was the ball python (snake). This is because these creatures have high resistance to damage, originating from skin surface design feature. This was the main reason in replicating its scale design on cutting tool surface. Orthogonal cutting test was performed on AISI/SAE 4140 at the cutting speeds of 283 and 628 m/min and a feed of 0.1 mm/rev to study the effects of structure shapes. Results showed that nature-inspired design structures significantly reduced forces, temperature, compression ratio, contact length and power consumption. Characterisation of sticking and sliding contact was also made.

MHD visco elastic Fluid flow and heat transfer over a stretching surface in presence of viscous dissipation, internal heat generation or absorption and work due to deformation has been investigated. The flow is influenced by linearly stretching sheet, in presence of heat generation/absorption of the wall. The problem has been solved numerically by shooting technique with fourth order RUNGE-KUTTA integration scheme. Heat Transfer analysis has been carried out for both prescribed surface temperature (PST) and prescribed power law heat flux (PHF) to get the effect of visco –elasticity (k1),Eckert number (Ec), heat source /sink (), and Prandle number (Pr) in presence and absence of magnetic field (Mn).

Surface structuring on cutting tools is a modern application of surface structuring that has shown improve- ments in tribological phenomena at tool-chip interface. Liter- ature suggests that this technique has been used mainly to structure the rake face of a cutting tool. This study reports on the performance of femtosecond laser-generated structures on both rake and flank faces of the cutting tool. The premise for fabricating structures on both faces of cutting tool was to have strong impact on tool wear and cutting forces so as to reduce power demands. Fabricated structures were in a form ofconventional micro-grooves.Performanceofstructureswas assessed in the machining of AISI/SAE 4140 over a conven- tional range of cutting speeds for the selected workpiece ma- terial. The orthogonal cutting tests to investigate the effects of structured tool on cutting forces, friction coefficient and flank land wear rate were performed. Results show that the struc- tured tool is effective in delivering better machining perfor- mance as compared to unstructured tool in terms of reduced friction coefficient by 14 %, cutting forces by 10 %, feed forces by 23 %, and compression ratio by 10 %. Characteri- sation of sticking and sliding contact was evaluated.

The creation of textures and structures on contact surfaces is of importance for improving contact conditions for mating surfaces. Laser machining shows promise as a prospective technique in the fabrication of micro- and nanometre scale structures on difficult-to-cut materials. This study provides new information on manufacturing process operating variables for the use of femtosecond lasers in structuring the carbide tool rake face with a view to improving the tool–chip contact phenomena. Experiments were based on a femtosecond Ti:sapphire laser system with a wavelength of 800 nm, pulse duration of 100 fs and repetition rate of 1 kHz. The effect of laser fluence and scanning speeds on the geometry and quality of the structures was investigated. The research draws upon the requirements for cutting tools and defines the best laser process parameters to preserve the effectiveness of the carbide material in machining. This work is important for innovative development of cutting tools, alleviating critical contact conditions on the tool–chip flow faces and reducing energy demand in machining.