Flowfield-dependent variant method for moving-boundary problems

A novel numerical scheme using the combination of flowfield-dependent variation method and arbitrary Lagrangian–Eulerian method is developed. This method is a mixed explicit–implicit numerical scheme, and its implicitness is dependent on the physical properties of the flowfield. The scheme is discretized using the finite-volume method to give flexibility in dealing with complicated geometries. The formulation itself yields a sparse matrix, which can be solved by using any iterative algorithm. Several benchmark problems in two-dimensional inviscid and viscous flow have been selected to validate the method. Good agreement with available experimental and numerical data in the literature has been obtained, thus showing its promising application in complex fluid–structure interaction problems

Assessment of Recycled Plastic Performance in The City of Zawia Libya

Plastic particles and other plastic pollutants exist in our environment and in the food chain and threaten human health. Inappropriate handling and disposal of plastic waste is a global problem and is still not resolved in many countries. When recycling companies need to deal with complex plastic, the problem becomes even more serious, which can prevent their recycling initiatives. The main purpose of this research is to determine whether recycled products can be used as post-consumer materials in various recycling ratios to produce new products without reducing quality. In the study, 0 percent, 20%, 50%, 70%, and 100 percent regrind ratios were used. Reduction, hardness, and solid density are the qualities studied. The results show that the properties did not change significantly

Assessment of Recycled Plastic Performance in The City of Zawia Libya

Plastic particles and other plastic pollutants exist in our environment and in the food chain and threaten human health. Inappropriate handling and disposal of plastic waste is a global problem and is still not resolved in many countries. When recycling companies need to deal with complex plastic, the problem becomes even more serious, which can prevent their recycling initiatives. The main purpose of this research is to determine whether recycled products can be used as post-consumer materials in various recycling ratios to produce new products without reducing quality. In the study, 0 percent, 20%, 50%, 70%, and 100 percent regrind ratios were used. Reduction, hardness, and solid density are the qualities studied. The results show that the properties did not change significantly

Effect of Various Plasticizers in Different Concentrations on :Physical, Thermal, Mechanical, and Structural Properties of :Wheat Starch-Based Films

Biocomposite materials are essential for environmental protection, as they have the ability of substituting synthetic plastic with natural materials. This work investigated how different plas¬ticizers (Glycerol (G), Fructose (F), Sorbitol (S), and Urea (U)) affect the morphological, mechanical, thermal, and physical characteristics of films made of wheat starch at various concentrations (0%, 15%, 25%, and 35%). Plasticizers were added to improve the flexibility and homogeneity of the wheat starch-based bioplastic. Control film exhibited high tensile strength (38.7 MPa) with low elon¬gation (1.9%). However, films plasticized with 35% sorbitol showed the highest elongation, which was 60.7% at break. At 35% of all plasticizers, fructose showed the highest tensile strength, with 7.6 MPa. The addition of different plasticizers shows improvement in water resistance; films plasticized with glycerol had the lowest water absorption at 35% fructose (187.4%) and also showed coherent surfaces. Glycerol, sorbitol, and urea films showed a higher mass loss compared to fructose films. Fructose showed the highest performance after the analysis of the results, with low water absorp¬tion, water content, and mass loss and with high mechanical performance at 35% of fructose. SEM images show that the addition of fructose and glycerol improves the surface homogenate, while sorbitol and urea have a less compact structure with large pores

Fear causes tears - Perineal injuries in home birth settings. A Swedish interview study

<p>Abstract</p> <p>Background</p> <p>Perineal injury is a serious complication of vaginal delivery that has a severe impact on the quality of life of healthy women. The prevalence of perineal injuries among women who give birth in hospital has increased over the last decade, while it is lower among women who give birth at home. The aim of this study was to describe the practice of midwives in home birth settings with the focus on the occurrence of perineal injuries.</p> <p>Methods</p> <p>Twenty midwives who had assisted home births for between one and 29 years were interviewed using an interview guide. The midwives also had experience of working in a hospital delivery ward. All the interviews were tape-recorded and transcribed. Content analysis was used.</p> <p>Results</p> <p>The overall theme was "No rushing and tearing about", describing the midwives' focus on the natural process taking its time. The subcategories 1) preparing for the birth; 2) going along with the physiological process; 3) creating a sense of security; 4) the critical moment and 5) midwifery skills illuminate the management of labor as experienced by the midwives when assisting births at home.</p> <p>Conclusions</p> <p>Midwives who assist women who give birth at home take many things into account in order to minimize the risk of complications during birth. Protection of the woman's perineum is an act of awareness that is not limited to the actual moment of the pushing phase but starts earlier, along with the communication between the midwife and the woman.</p

Comparison of High-order Accurate Schemes for Solving the Nonlinear Viscous Burgers Equation

Abs tract: In this paper, a comparis on between h ig h e r order s chemes has been performed in terms of numerical accuracy. Four finite difference s chemes, the e xp lic it fourth-order compact Pade scheme, the implicit fourth-order Pade scheme, flowfield dependent variation (FDV) meth o d a n d h igh order compact flowfie ld dependent variation (HOC-FDV) s cheme are tes ted. The FDV s cheme is us ed for time dis c retization and the fourth-order compact Pade scheme is us ed for s patial derivatives. The s olution procedures c o n s is t of a number of tri-diagonal matrix operations and produce an efficient s olver. The comparis ons are performed u s in g one dimens ional nonlinear vis cous Burgers equation to demons trate the accuracy and the convergence characteris tics o f the high-resolution s chemes. The numerical results s how that HOC-FDV is highly accurate in co mparis on with analytical and with other higher order schemes

A High Order Compact-Flowfield Dependent Variation (HOC-FDV) method for inviscid flows

In this paper, a single high-order compact flowfield-dependent variation (HOC-FDV) method is developed, valid for two�dimensional inviscid compressible as well as incompressible flow problems. The method has third-order accuracy in time and fourth�order accuracy in space. The FDV scheme is used for time dis�cretization and the fourth-order compact Pade scheme is used for spatial derivatives. The solution procedure consists of a number of tri-diagonal matrix operations and produces an accurate solver. Numerical examples are solved to demonstrate the accuracy and convergence characteristics of the high-resolution scheme. The test cases are flow over a compression corner, a channel flow with com�pression/expansion, and a flow past NACA 0012 airfoil. The numer�ical results show an excellent agreement with analytical and pub�lished numerical results and they clearly demonstrate the higher accuracy of a single HOC-FDV scheme for both incompressible and compressible flows

Higher Order Compact-Flowfield Dependent Variation (HOC-FDV) solution of one-dimensional problems

In this paper, a novel higher order accurate scheme, namely high order compact flowfield dependent variation (HOC-FDV) method has been used to solve one-dimensional problems. The method is fourth order accurate in space and third order accurate in time. Four numerical problems; the nonlinear viscous Burger’s equation, transient Couette flow, the shock tube (Sod problem) and the interaction of two blast waves are solved to test the accuracy and the ability of the scheme to capture shock waves and contact discontinuities. The solution procedure consists of tri-diagonal matrix operations and produces an efficient solver. The results are compared with analytical solutions, the original FDV method, and other standard second order methods. The results also show that HOC-FDV scheme provides more accurate results and gives excellent shock capturing capabilities