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The purpose of this study is to analyze hybrid nanofluid (MWCNTs+Ag+Kerosene oil) over a stretched cylinder. Flow analysis is carried out in presence of stagnation-point. Features of heat transport are examined via melting conditions.

Governed expression (partial differential equations) for flow and heat transfer are transmitted into ordinary differential equations (ODEs) via applying adequate transformations. For solutions development shooting method (bvp4c) is used on these non-linear coupled ODEs.

Comparative observation among hybrid nanofluid (MWCNTs+Ag+Kerosene oil), basefluid (kerosene oil) and nanofluid (MWCNTs+Kerosene oil) are performed. Influences of physical parameters on heat transfer rate, velocity, skinfriction coefficient and temperature are visualized graphically. Higher values nanoparticle volume fractions, curvature parameter, melting parameter and velocity ratio parameter lead to intensification in the velocity profile. The temperature of the fluid reduces with higher values nanoparticle volume fractions, curvature parameter and melting parameter. The surface friction coefficient is minimized via a higher melting parameter and velocity ratio parameter. Heat transmission rate intensifies with velocity ratio parameter, nanoparticle volume friction and curvature parameter while it reduces gradually with larger melting parameter. During comparative study performance of hybrid nanomaterial (MWCNTs+Ag+Kerosene oil) is outstanding and is proceeded by nanomaterial (MWCNTs+ Kerosene oil) and basefluid (kerosene oil).

In the presented study authors have analyzed the flow of hybrid nanomaterial (MWCNTs+Ag+Kerosene oil) by a stretching cylinder. The further cylinder is subjected to stagnation point and melting condition. The authors believe that all the consequences of the presented study and numerical technique (bvp4c) are original and not published before.

The purpose of this study is to look into the hygroscopic and tribo-mechanical properties of a polypropylene/polyamide-6 (PP/PA6) blend and a PP/PA6/Boron sesquioxide composite.

The hygroscopic behaviour of the PP/PA6 blend and PP/PA6/Boron sesquioxide composite was studied using a water contact angle goniometer in this study. To validate the hygroscopic behaviour of the blend and composite, water contact angles and surface energy of the materials were investigated. Tensile strength and hardness tests were used to determine mechanical characteristics, and tribological experiments on a pin-on-disc tribometer were used to demonstrate the friction and wear rates of dry and water-conditioned blends and composites. The melting temperature of dry and water-conditioned composites was determined using DSC analysis.

The hygroscopic effect of the PP/PA6 blend was found to be minimal in the experiment, while it was relatively dominating in the PP/PA6/Boron sesquioxide composite. Tensile strength was found to be somewhat lower in blend and composite compared to virgin PP, whereas hardness was found to be higher in both blend and composite. The composite’s tribological testing findings were fairly outstanding, with the coefficient of friction (COF) and wear rates significantly reduced due to boron sesquioxide reinforcement. The reaction between boron sesquioxide and water molecules produced boric acid, which increased the tribological characteristics of the composite even further. Following 30 days of water conditioning, the weight of the blend increased by 3.64% and the weight of the composite increased by 6.45% as compared to the dry materials. After water conditioning, tensile strength reduced by 0.8% for the blend and 14.16% for the composite. Hardness was determined to be the same in the dry state and after water-conditioning for blend but dropped 1% for composite. As compared to blend, the COF and wear resistance of composite were 15.52% and 25.16% higher, respectively. After absorbing some water, the results increased to 28.57% and 34.9%, respectively.

The mechanical and thermal behaviour of polymer composites (particularly polyamide composites) vary depending on the surrounding environment. Tests were carried out to explore the effect of water treatment on the tribo-mechanical and thermal characteristics of PP/PA6/Boron sesquioxide composite. Water treatment caused polyamides to bind with water molecules, resulting in voids in the material. The interaction between boron sesquioxide and water molecules produced boric acid, which increased the tribological characteristics of the composite.

Recently, the usage of melt blown products in many areas has increased. In melt blown process, generally polymers have been used. There are a variety of polymers. Characteristics of melt blown nonwovens have changed significantly depending on the polymer type. Also, there are several parameters such as die temperature, die-to-collector distance (DCD), air pressure, etc. that modify the nonwovens in melt blown process. The purpose of this paper is to investigate the effect of these parameters on the characteristics of nonwovens made up of polyethylene (PE).

In the melt blown process, two die temperatures, three different die air pressures and three different DCDs were used. In total, 18 samples were produced. On produced samples, thickness, tear and tensile strengths, fiber diameter, basis weight tests were done. Also SEM observations were obtained.

It was observed that parameters studied have a significant effect on characteristics of the produced nonwoven. Fiber diameter, basis weight and strength decrease by depending on factors. Also, it was observed that temperature has an effect, but slight. This work shows that higher temperatures should be studied. Finer and uniform fiber diameter is obtained with an increase in air pressure.

PE is becoming increasingly important in nonwovens due to its lower melting point for processing and softer feel in nonwoven products.

Although the use of PE in polymer-laid nonwovens, especially as bicomponent fibers, has been growing in recent years, there are limited data on their processability and performance. In this context, with the availability of relatively higher melt flow rate PE, understanding the processability and structure and properties of the melt blown PE is very helpful in designing and developing the right products. This research was conducted to evaluate the processability of the PE resin using a typical PP melt blowing pilot line and to determine the structure and properties of the formed webs.

PE has superior properties such as excellent chemical resistance, good fatigue, wear resistance and higher impact strength. Also, PE provides good resistance to organic solvents, degreasing agents and electrolytic attack. PE has lower working temperatures than polypropylene, is light in weight, resistant to staining and has low moisture absorption rates. Thus, this study provides important contributions to the area since there are no data reported about the effect of various processing parameters on the structure and properties of PE melt blown nonwovens.

IN recent years several interesting and excellent papers have been read before various Societies, dealing with magnesium and its alloys.

3D printing based on additive manufacturing has advantages in manufacturing products with high geometrical complexity. However, there are many limitations to print plastic products with the existing commercial 3D printers. The polymer materials processing industry needs new devices which can satisfy the trend of processing individual units and small batch sizes of plastic parts.

In this study, a freeform fabrication system with the method of polymer melt droplet deposition is proposed. The performance of this system under different conditions was studied by changing the operating parameters. Furthermore, the dimensional uniformity of droplets and their deposition process are analyzed, and a plastic sample was fabricated with this system as an example.

The results show a clear correlation between the processing parameters and the droplet diameter. In the experiment for examining the dimensional uniformity of the droplet, the droplets become spindles, and there appears a melt filament between the droplets. The variation of the droplet’s diameters is within 5 per cent. Furthermore, a successfully processed rectangular plastic sample verified the feasibility of this technology for the printing of plastic products.

A freeform fabrication system with polymer melt droplet deposition is proposed, which can process a wide variety of materials in the form of standard granulates like injection molding or extrusion. Based on the principle of droplet deposition, multi-component or colorful materials can be printed.

Due to the complexity of and variations in additive manufacturing (AM) processes, there is a level of uncertainty that creates critical issues in quality assurance (QA), which must be addressed by time-consuming and cost-intensive tasks. This deteriorates the process repeatability, reliability and part reproducibility. So far, many AM efforts have been performed in an isolated and scattered way over several decades. In this paper, a systematically integrated holistic view is proposed to achieve QA for AM.

A systematically integrated view is presented to ensure the predefined part properties before/during/after the AM process. It consists of four stages, namely, QA plan, prospective validation, concurrent validation and retrospective validation. As a foundation for QA planning, a functional workflow and the required information flows are proposed by using functional design models: Icam DEFinition for Function Modeling.

The functional design model of the QA plan provides the systematically integrated view that can be the basis for inspection of AM processes for the repeatability and qualification of AM parts for reproducibility.

A powder bed fusion process was used to validate the feasibility of this QA plan. Feasibility was demonstrated under many assumptions; real validation is not included in this study.

This study provides an innovative and transformative methodology that can lead to greater productivity and improved quality of AM parts across industries. Furthermore, the QA guidelines and functional design models provide the foundation for the development of a QA architecture and management system.

This systematically integrated view and the corresponding QA plan can pose fundamental questions to the AM community and initiate new research efforts in the in-situ digital inspection of AM processes and parts.

Describes a new finite element scheme for the large‐scale analysis of compressible and incompressible viscous flows. The scheme is based on a combined compressible‐ incompressible Galerkin least‐squares (GLS) space‐time variational formulation. Three‐ dimensional unstructured meshes are employed, with piecewise‐constant temporal interpolation, local time‐stepping for steady flows, and linear continuous spatial interpolation in all the variables. The scheme incorporates automatic adaptive mesh refinement, with a choice of various error indicators. It is implemented on a distributed‐memory parallel computer, and includes an automatic load‐balancing procedure. Demonstrates the ability to solve both compressible and incompressible viscous flow problems using the parallel adaptive framework via numerical examples. These include Mach 3 flow over a flat plate, and a divergence‐free buoyancy‐driven flow in a cavity. The latter is a model for the steady melt flow in a Czochralski crystal growth process.

A survey of licensed premises in Leeds was carried out during 1986. The quality of ice was investigated and survey sheets were completed. Hygienic practices were found to be poor and contamination of the ice was found to have occurred, largely due to staff not following manufacturers' instructions in the use of ice‐making machines, and to handling the ice as opposed to using a utensil. A wider study is recommended.

In Northern Regions, ice covers that form on rivers, streams, and lakes with the onset of winter, cause various problems related to winter navigation and pollution dispersion among others. Warm water, from industrial plants, discharged into these rivers cause partial or total melting of the ice cover over considerable distances. The present work investigates the melting of a thin non‐uniform ice cover subject to varying water and air temperatures under turbulent flow conditions. A two‐dimensional depth averaged turbulence model coupled with a heat transfer model is used to simulate laboratory conditions of ice cover melting. Computational results were compared with experimental investigations. The average melting of the ice cover was found to be in close agreement with the experimental measurements with the exception of the leading edge region.

Depending on an experimental approach to find optimal parameters for producing fully dense (relative density > 99%) Inconel 718 (IN718) components in the selective laser melting (SLM) process is expensive and offers no guarantee of success. Accordingly, this study aims to propose a multi-scale simulation framework to guide the choice of processing parameters in a more pragmatic manner.

In the proposed approach, a powder layer, ray tracing and heat transfer simulation models are used to calculate the melt pool dimensions and evaporation volume corresponding to a small number of laser power and scanning speed conditions within the input design space. A layer-heating model is then used to determine the inter-layer idle time required to maximize the temperature convergence rate of the solidified layer beneath the power bed. The simulation results are used to train surrogate models to construct SLM process maps for 3,600 pairs of the laser power and scanning speed within the input design space given three different values of the underlying solidified layer temperature (i.e., 353 K, 673 K and 873 K). The ideal selection of laser power and scanning speed of each process map is chosen based on four quality-related criteria listed as follows: without the appearance of key-hole melting; an evaporation volume less than the volume of the d90 powder particles; ensuring the stability of single scan tracks; and avoiding a weak contact between the melt pool and substrate. Finally, the optimal laser power and scanning speed parameters for the SLM process are determined by superimposing the optimal regions of the individual process maps.

The feasibility of the proposed approach is demonstrated by fabricating IN718 test specimens using the optimal processing conditions identified by the simulation framework. It is shown that the maximum density of the fabricated parts is 99.94%, while the average density is 99.88% and the standard deviation is less than 0.05%.

The present study proposed a multi-scale simulation model which can efficiently predict the optimal processing conditions for producing fully dense components in the SLM process. If the geometry of the three-dimensional printed part is changed or the machine and powder material is altered, users can use the proposed method for predicting the processing conditions that can produce the high-density part.