Cylindrical Material Research Articles

Evaluating the Durability Assessment of Cementitious Materials Under Sulfate Attack

This paper aims to evaluate whether the aforementioned method represents well the global expansion of the specimens. In the present experimental work, two mixtures of cylindrical cementitious materials exposed to sulfate solution are investigated. Those mixtures differ in the average size of coarse aggregates, yet have an identical specific surface area (SSA), which is the total surface of aggregates in a specimen. This attempt aims to isolate the effect of SSA in the sulfate attack mechanism, as the deterioration level is proportional to the SSA. An advance analysis was performed to observe deeply the phenomena experienced by the specimens, in micro, intermediate, and macro scales. The proposed analysis is also capable to predict the deterioration of the specimens such as mass variation, with excellent results. The results, like the most previous studies, show that the specimen with larger aggregates experienced more elongation. Interestingly, the other specimen, who’s the aggregates are smaller, presented a considerably greater expansion of the radius. The results prove that both specimens likely experienced an identical volumetric expansion but in different ways. Finally, this work suggests that observing expansion by only measuring the elongation should be evaluated.

Influence of design on performance of a latent heat storage system at high temperatures

This work focuses on the design of a low cost utility scale thermal storage, consisted of vertically placed cylindrical phase change material capsules, for next-generation power plants. In this paper a simple model for the design of a storage unit is presented. This model includes both latent and sensible heat stored in phase change material. The exergetic efficiency and the operation time of the storage is considered as the design criterion in this model and the influence of various design parameters on the exergetic efficiency and operation time is investigated. Results show that under study conditions exergetic efficiency varies between 98.991% and 98.692% and operation time changes between 4h and 21h. Higher efficiency values obtained for lower number of capsules, lower heat transfer fluid flow rates and lower distance between capsules. Decreasing number of capsules and the distance between capsules also decreases the operation time. However, the decrease in the flow rate increases the operation time.

An Anisotropic Elastic-plastic Model for the Optimization of a Press Machine’s Auxiliary Worktable Plate Thickness

In this work an anisotropic elastic–plastic finite element model strongly coupled with ductile damage is applied to determine the suitable thickness of added auxiliary worktable plate to a 100 ton maximum capacity press machine. The major focus of this study is to minimize the amount of stress transmitted to the optional worktable plate and the press machine body while allowing them to withstand plastic deformation and damage during compression testing until final sample fracture. The worktable plates and the press machine body are made of TRIP800 grade steel. AISI 316L stainless steel is chosen as test material for the cylindrical billets. The proposed model is based on a non-associative plasticity theory and the “Hill 1948” quadratic (equivalent) stress norm is considered to describe the large plastic anisotropic flow accounting for mixed isotropic and kinematic hardening with isotropic damage effect. For each material the model uses an experimental data base obtained from a set of tensile tests conducted until the final fracture in three directions, the rolling direction (RD) or 0, the transverse direction (TD) or 90, and the 45 direction. After several numerical simulations of compression testing using ABAQUS/Explicit FE® software, thanks to the user’s developed VUMAT subroutine, varying cylindrical billet diameters and material, worktable plates number and thicknesses and spatial plate configurations the solution of 100mm thick worktable plate is selected since in that case the cylinder specimen is totally damaged and the stress state inside the worktable plates and the press machine body remains admissible.

Developing and characterizing human biomimetic arteriole for studying pulmonary hypertension

Arteriolar resistance vessels control flow to vascular beds. The structure, mechanics, and function of these blood vessels are critically important to our understanding of the mechanisms of cardiovascular disease pathogenesis. Additionally, in vitro arteriolar mimetic approaches are needed to improve the study of cardiovascular disease, because models based upon rodents vascular function and cells in standard culture containers do not accurately recapitulate the native multicellular architecture of a human vessel wall. Here, we describe novel, highly parallel, mass biofabrication of biomimetic tubular vessel constructs composed of biocompatible scaffold materials, pulmonary microvascular endothelial cells (HPMEC), extracellular matrix components including fibronectin and laminin 3, and human pulmonary artery smooth muscle cells (HPASMC). These constructs had a diameter of ~250 microns, and a length of 1–3 mm. Cells were incorporated into these constructs in patterns that mimic the layering and relative alignment observed in human pulmonary arterioles. Finite Element Analysis showed that the ultra‐thin cylindrical scaffold materials used here could be displaced by the cells in these biomimetic vascular walls to an extent that was similar to displacements of thicker tube composed of softer materials. HPMEC in these biomimetic vessel constructs produced more nitric oxide, and demonstrated higher phosophorylation levels of key nitric oxide signaling proteins (eNOS and Akt) than equal numbers of cells grown on equal surface areas that were flat. Additionally, HPASMC were aligned at tunable angles that mimicked in‐vivo organization using biomolecular micropatterning. Thus, biomimetic arterioles produced in this study exhibited improved endothelial functionality together with multi‐cellular layering and anatomically accurate cellular alignment, and provide a platform for investigation of microvascular function.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Biological evaluation and finite-element modeling of porous poly(para-phenylene) for orthopaedic implants

Poly(para-phenylene) (PPP) is a novel aromatic polymer with higher strength and stiffness than polyetheretherketone (PEEK), the gold standard material for polymeric load-bearing orthopaedic implants. The amorphous structure of PPP makes it relatively straightforward to manufacture different architectures, while maintaining mechanical properties. PPP is promising as a potential orthopaedic material; however, the biocompatibility and osseointegration have not been well investigated. The objective of this study was to evaluate biological and mechanical behavior of PPP, with or without porosity, in comparison to PEEK. We examined four specific constructs: 1) solid PPP, 2) solid PEEK, 3) porous PPP and 4) porous PEEK. Pre-osteoblasts (MC3T3) exhibited similar cell proliferation among the materials. Osteogenic potential was significantly increased in the porous PPP scaffold as assessed by ALP activity and calcium mineralization. In vivo osseointegration was assessed by implanting the cylindrical materials into a defect in the metaphysis region of rat tibiae. Significantly more mineral ingrowth was observed in both porous scaffolds compared to the solid scaffolds, and porous PPP had a further increase compared to porous PEEK. Additionally, porous PPP implants showed bone formation throughout the porous structure when observed via histology. A computational simulation of mechanical push-out strength showed approximately 50% higher interfacial strength in the porous PPP implants compared to the porous PEEK implants and similar stress dissipation. These data demonstrate the potential utility of PPP for orthopaedic applications and show improved osseointegration when compared to the currently available polymeric material. Statement of significancePEEK has been widely used in orthopaedic surgery; however, the ability to utilize PEEK for advanced fabrication methods, such as 3D printing and tailored porosity, remain challenging. We present a promising new orthopaedic biomaterial, Poly(para-phenylene) (PPP), which is a novel class of aromatic polymers with higher strength and stiffness than polyetheretherketone (PEEK). PPP has exceptional mechanical strength and stiffness due to its repeating aromatic rings that provide strong anti-rotational biaryl bonds. Furthermore, PPP has an amorphous structure making it relatively easier to manufacture (via molding or solvent-casting techniques) into different geometries with and without porosity. This ability to manufacture different architectures and use different processes while maintaining mechanical properties makes PPP a very promising potential orthopaedic biomaterial which may allow for closer matching of mechanical properties between the host bone tissue while also allowing for enhanced osseointegration. In this manuscript, we look at the potential of porous and solid PPP in comparison to PEEK. We measured the mechanical properties of PPP and PEEK scaffolds, tested these scaffolds in vitro for osteocompatibility with MC3T3 cells, and then tested the osseointegration and subsequent functional integration in vivo in a metaphyseal drill hole model in rat tibia. We found that PPP permits cell adhesion, growth, and mineralization in vitro. In vivo it was found that porous PPP significantly enhanced mineralization into the construct and increased the mechanical strength required to push out the scaffold in comparison to PEEK. This is the first study to investigate the performance of PPP as an orthopaedic biomaterial in vivo. PPP is an attractive material for orthopaedic implants due to the ease of manufacturing and superior mechanical strength.

The electro-thermal stability of tantalum relative to aluminum and titanium in cylindrical liner ablation experiments at 550 kA

Presented are the results from the liner ablation experiments conducted at 550 kA on the Michigan Accelerator for Inductive Z-Pinch Experiments. These experiments were performed to evaluate a hypothesis that the electrothermal instability (ETI) is responsible for the seeding of magnetohydrodynamic instabilities and that the cumulative growth of ETI is primarily dependent on the material-specific ratio of critical temperature to melting temperature. This ratio is lower in refractory metals (e.g., tantalum) than in non-refractory metals (e.g., aluminum or titanium). The experimental observations presented herein reveal that the plasma-vacuum interface is remarkably stable in tantalum liner ablations. This stability is particularly evident when contrasted with the observations from aluminum and titanium experiments. These results are important to various programs in pulsed-power-driven plasma physics that depend on liner implosion stability. Examples include the magnetized liner inertial fusion (MagLIF) program and the cylindrical dynamic material properties program at Sandia National Laboratories, where liner experiments are conducted on the 27-MA Z facility.

Sound radiation of cylinder in shallow water investigated by combined wave superposition method

It can be a difficult problem to precisely predict the sound field radiated from a finite elastic structure in shallow water channel because of its strong coupling with up-down boundaries and the fluid medium, whose sound field cannot be calculated directly by current methods, such as Ray theory, normal mode theory and other different methods, which are adaptable to sound fields from idealized point sources in waveguide. So far, there is no reliable prediction method to solve this kind of problem. A combined wave superposition method is proposed for such a problem, which combines the traditional wave superposition method with the transfer function in shallow water channel and the multi-physics field coupling numerical model. This method mainly consists of three sections:1) obtaining the normal velocity on the elastic structure surface in shallow water channel by the finite element method (FEM), whose FEM model includes the up-down boundaries and the completely absorbent sound boundaries in the horizontal direction; 2) getting the equivalent point source strength by traditional wave superposition method; 3) calculating the total sound field by adding up each point source field which is obtained by normal mode method. This method is verified by numerical simulation and theoretical analysis by using an imaginary and elastic spherical sound source respectively, and the results demonstrate that the method is valid and has high precision and calculating efficiency. The acoustic radiation characteristics from elastic cylindrical shells is investigated for different acoustic radiation sources, ocean environments and measurements. The cylindrical shell material is steel, whose radius and length are 3 m and 30 m respectively. The shallow water channel is an ideal waveguide with 50 m in depth, at the upper boundary, i.e., the free surface, the lower boundary is the Neumann boundary, i.e., the normal derivative of the acoustic pressure should be zero. The analysis frequency range is from 30 Hz to 200 Hz. The results show that due to a significant coupling effect of up-down direction boundaries on the sound field, the elastic structure can be equivalent to the point source only in low frequency and far field. The spatial field directivity distribution is more obvious at high frequency. The acoustic power measured by vertical line arrayis greatly influenced by ocean boundary and the depth of target.

Numerical modelling of cylindrical composite materials heating in dynamic modes

Presented paper describes the dynamic processes, which are happens during the process of creating the steel pipes with protection layer. This protection layer saves the pipes from chemical reactions on inner or outer side during their using in industry processes. The main aim of presented work is receiving of requested temperature profile in the place of connection of the steel and protection material.

A Method to Assess Transverse Vibration Energy of Ship Propeller Shaft for Diagnostic Purposes

Abstract The article discusses a key problem of ship propulsion system vibration diagnostics, which concerns assessing this part of mechanical energy transmitted from the main engine to the ship propeller which is dissipated due to propeller shaft vibration. A simplified calculation model is proposed which allows the total energy of the generated torsional vibration to be assessed from the shaft deflection amplitude measured at the mind-span point between the supports. To verify the developed model, pilot tests were performed on the laboratory rotational mechanical system test rig. In those tests, cyclic bending moment was applied to a unified (cylindrical) material sample, which modelled, at an appropriate scale, structural and functional properties of a real propeller shaft.

Utilization of rice husks in a water-permeable material for passive evaporative cooling

This research aims to use the byproducts of rice processing: the rice husk, coarse rice bran and rice polish, to experimentally develop a water-permeable material for evaporative cooling. The starting materials consisted of laterite, fine sand, Portland cement, rice byproducts and water. Mixtures with different material proportions were molded into interlocking blocked and cylindrical shapes, dried and cured in air indoors. In interlocking blocks connected into a column, the proportion of laterite, fine sand, Portland cement and coarse rice bran with a ratio of 4:2:1:3 absorbed the most water and yielded a maximum water height of 42 cm. In the cylindrical porous material, the maximum water height of 54 cm was found in the mixture with volumetric proportions of 3:2:1:4. The pore sizes of the porous cylinder were in the range of 0.03–3 μm. The investigation of the thermal performance of the developed material was conducted in an experimental chamber with an air temperature of 32–37 °C and relative humidity of 54–76% flowing through four rows of water soaking porous cylinders. The distance between two rows of water soaking porous cylinders was also varied from 11.2 cm to 14.0 cm and 16.8 cm. The air temperature was found to be reduced by 0.5-2.7 °C. The highest temperature reduction was found in the porous cylinders that had a distance between the rows of 16.8 cm and operated under high air temperature. The water consumption of 31.6 mL/h was lowest for the porous cylinder with a distance between two rows 16.8 cm apart. The developed product was appropriate for evaporative cooling in agricultural houses and outdoor spaces.

Characterization and machining performance of laser-textured chevron shaped tools coated with AlTiN and AlCrN coatings

Owing to increased demands of more efficient cutting tools for machining difficult to cut materials and environment friendly cutting operations, laser textured tools have become necessary. The characterization and machining studies with such laser textured tools coated with hard ceramic coatings are the prime motivation for this present work. The main aspect of the study is to evaluate two different PVD coated (AlTiN and AlCrN) laser textured tools. In the first stage, laser textured tools were prepared with novel chevron shaped textures on tool rake face using nanosecond pulse laser. This stage is followed by PVD coatings of AlTiN and AlCrN coatings by cathodic arc evaporation (CAE) technique. Coating characterization studies were conducted considering coating morphology, surface roughness, coating elemental analysis and phase analysis of coated and coated textured tools. The performance of the different tools thus manufactured was evaluated by carrying out suitable turning experiments on cylindrical Ti6Al4V work material under dry cutting environment. Machining results were evaluated in terms of cutting force, flank wear progress, rake surface analysis, and chip underside study. Further, static diffusion couple test (SDCT) has been conducted to understand diffusion wear mechanism in plain and textured tools. A new concept of derivative cutting or interfacial multipoint micro-cutting (IMP-μC) on chip underside surface due to texture patterns and a reduction of derivative cutting due to coatings on the textured tools have been proposed.

Numerical data used for producing failure assessment diagram in integrity analysis of cylindrical shell with crack

PurposeIntegrity assessment is used to ensure reliability operation of a pressurized equipment containing defects. Based on data of cylindrical shell dimensions, operation conditions, material properties and crack dimensions, an assessment can be carried out, using either Level 1, Level 2 or Level 3 procedure. Assessment using Level 3 procedure within the code requires a finite element simulation in order to generate both the evaluation point and the failure assessment diagram (FAD) that serves as the acceptance criteria. The purpose of this paper is to provide the numerical data which are used for integrity assessment of a pressure vessel containing crack. Here, a parametric study has been carried out to generate such result for the cases of longitudinal crack defect in a cylindrical shell for a number of common cases, in terms of thickness-to-radius ratio, crack size ratio and crack aspect ratio.Design/methodology/approachThe evaluation of stress intensity factor is determined through J-integral parameter found using a finite element analysis with a specially meshed strategy incorporating the crack. A comparison is made against stress intensity factor provided by the code.FindingsA good agreement is obtained with percent error of 2.13 percent for low aspect ratio crack, and 0.57 percent for high aspect ratio crack. Furthermore, a study has been carried out using the methodology for 160 cases, covering both cases already available in the code and other cases of crack in cylindrical shells. The result can be used as a complement to the existing tabular data available in the code for Level 2 assessment, to be used for integrity analysis of damaged cylindrical shells based on the FAD criteria.Originality/valueThe result can be used as a complement to the existing tabular data available in the API 579 code for Level 2 assessment, to be used for integrity analysis of damaged cylindrical shells based on the FAD criteria. New equations were generated based on finite element analysis and can be used for Level 3 assessment of the code.

Ligno-cellulosic materials as air-water separators in low-tech microbial fuel cells for nutrients recovery

Low-cost materials and low-tech architectures could give competitive advantage in scaling-up applications of microbial fuel cells (MFC), especially for nutrients recovery from wastewater. Here a novel concept is presented, based on cylindrical ligno-cellulosic materials, available as agricultural residues or spontaneous vegetation. Giant canes (Arundo Donax L.) and maize (Zea Mays) stalks were used as porous separators (naturally tubular) for air-cathode MFC modules (GC-MFC and MS-MFC, meaning Giant Cane and Maize Stalk, respectively), with carbon cloth-based electrodes. The MFCs were operated across 100 Ω external load, enriching swine-farming wastewater with addition of sodium acetate (3 g L−1). Initially, these systems showed relatively high internal resistances (especially GC, with Rint = 5600 Ω), before the material was completely imbibed by the anolyte. After 10–20 days acclimation, despite sufficient electrolytic conductivity was established in both systems (internal resistance around 60–90 Ω), relatively low power densities (around 40 mW m−2, normalized by cathode's surface projection) were achieved, if compared to state-of-the-art MFCs, oriented to electricity harvesting. However, the generated electric field was enough to sustain electro-osmotic ions mobility and to establish high pH conditions (pH 11–12) at the cathode. Over 70 days of operation, electro-migration and deposition phenomena of valuable elements (Na, Ca, Mg, Mn, K, etc.) were observed, both inside the separator and on the cathode surface. Simultaneously, partial biodegradation of the ligno-cellulosic biomass, especially for MS, drove partial release of organic carbon, nitrogen, phosphorous and other elements in the anodic chamber. These relevant phenomena have to be taken into account in view of possible applications of ligno-cellulosic materials in MFC-driven nutrients recovery from wastewater.

Determination of heat transfer parameters by use of finite integral transform and experimental data for regular geometric shapes

This article offers a study on estimation of heat transfer parameters (coefficient and thermal diffusivity) using analytical solutions and experimental data for regular geometric shapes (such as infinite slab, infinite cylinder, and sphere). Analytical solutions have a broad use in experimentally determining these parameters. Here, the method of Finite Integral Transform (FIT) was used for solutions of governing differential equations. The temperature change at centerline location of regular shapes was recorded to determine both the thermal diffusivity and heat transfer coefficient. Aluminum and brass were used for testing. Experiments were performed for different conditions such as in a highly agitated water medium (T = 52 °C) and in air medium (T = 25 °C). Then, with the known slope of the temperature ratio vs. time curve and thickness of slab or radius of the cylindrical or spherical materials, thermal diffusivity value and heat transfer coefficient may be determined. According to the method presented in this study, the estimated of thermal diffusivity of aluminum and brass is 8.395 × 10−5 and 3.42 × 10−5 for a slab, 8.367 × 10−5 and 3.41 × 10−5 for a cylindrical rod and 8.385 × 10−5 and 3.40 × 10−5 m2/s for a spherical shape, respectively. The results showed there is close agreement between the values estimated here and those already published in the literature. The TAAD% is 0.42 and 0.39 for thermal diffusivity of aluminum and brass, respectively.

Morphology of Chitosan-Based Hollow Cylindrical Materials with a Layered Structure

The surface morphology and supramolecular structure of chitosan-based hollow cylindrical structures (microtubes) obtained by wet and dry–wet spinning were studied with the use of salting-out agents of various chemical nature by scanning electron microscopy. All samples are characterized by a layer-oriented porous structure, whose morphological features are determined by the spinning process and the chemical nature of the reagent for the polymer conversion polysalt → polybase reaction. An explanation of the formation of this layered structure is proposed within the framework of the Liesegang phenomenon. The influence of the nature of the salting-out agent on the mechanism of the chemical reaction and the polymer material structure was assessed. All microtube samples are shown to be characterized by anisotropy of their mechanical properties. When stretching in the longitudinal direction, an almost linear load–strain relationship is observed with the elastic component predominance, while stretching in the transverse direction yields a nonlinear one with the predominance of plastic deformation.

Acoustic absorption of fibro-granular composite with cylindrical grains

This paper reports the influence of cylindrical granular materials on the acoustic absorption performance of a natural fiber composite. The acoustic absorption behavior of an innovative fibro-granular composite composed of natural fibers combined with granular materials was investigated. The fibrous part of this new composite is fabricated using coconut coir fiber and the granular part by cylindrical rice husk grain. This study was motivated by a desire to improve the acoustical performance of materials made from natural (coir) fibers. The amount of binder additive added during composite preparation was considered by reconstructing the equation using fiber diameter as a new parameter. The acoustic properties of the novel composite were investigated based on the well-known Johnson-Champoux-Allard model by varying different physical parameters. The experimental analysis was performed in impedance tube to validate the analytical outcome. The developed analytical model employing Johnson-Champoux-Allard model was found to give predictions in good agreement with absorption coefficient data for the composite material samples with four different thicknesses. The effect of varying the different factors, such as sample thickness, fiber–grain size and fiber-grain ratio, on the acoustic absorption performance and the effect of the binder additive were also investigated. Results confirmed the potential of the new material as a promising acoustic absorber in the low-frequency region (less than 1kHz).

Cyclic extrusion compression angular pressing (CECAP) as a novel severe plastic deformation method for producing bulk ultrafine grained metals

In the current study, a novel severe plastic deformation (SPD) technique entitled cyclic extrusion channel angular pressing (CECAP) is proposed appropriate for producing ultrafine grained cylindrical material. In this new method, cyclic extrusion compression (CEC) and equal channel angular pressing (ECAP) processes are combined which solves drawbacks of both processes. Advantageous of the new process may be considered in two views of points of processing and properties. This new process increases the hydrostatic compressive stress of ECAP as well as shear to the total strain of CEC. Also, CECAP solves needing back pressure problem of CEC process which is an important feature of the new process. The process treated an AZ91 alloy and remarkable grain refinement and significant improvement in strength, ductility and hardness were achieved because of higher hydrostatic compressive stresses.

In situ hydrodeoxygenation of phenol with liquid hydrogen donor over three supported noble-metal catalysts

In situ hydrodeoxygenation of phenol with liquid hydrogen donor over three supported Pd, Pt, and Ru catalysts was investigated. The method of incipient wetness impregnation was used to load the three noble metals on the support of MCM-41, which is a cylindrical mesoporous material with a hierarchical structure. The in situ hydrodeoxygenation of phenol was conducted at 280°C, under pressures from saturated vapor of solvent and compressed initial N2 with gas products. Among the three catalysts, Ru/MCM-41 was found to be the best one, with highest phenol conversion of 73.9% and deoxygenation degree of 72.2%. The performance of Ru/MCM-41 increased with increasing theoretical loading amount of Ru and with reduction temperature. However, when the reduction temperature reached to 500°C, or the Ru theoretical loading amount increased to 15wt%, the activity of Ru/MCM-41 decreased reversely. Through the characterizations by small-angle XRD, wide-angle XRD, H2-TPR, and SEM analysis, the reason for the deteriorated performance of Ru/MCM-41 under high reduction temperature or high Ru loading amount was deduced as the collapse of MCM-41 structure and severe overlaps of Ru atoms. Hydrogen donors were also tested, and formic acid was found in best performance owing to its fast decomposition rate and high productivity of hydrogen. Though an increased feed ratio of formic acid to phenol could improve the hydrodeoxygenation potential of phenol, much simultaneously generated COx from decomposition of formic acid might occupy active sites of the catalyst and led to a decreased growth rate of phenol conversion.

Observational study of modified solar still coupled with oil serpentine loop from cylindrical parabolic concentrator and phase changing material under basin

The performance of a cylindrical parabolic concentrator with focal pipe - coupled with a developed solar still with (oil heat exchanger, Phase Change Material (PCM)) have been experimentally investigated to improve the freshwater productivity. The cylindrical parabolic concentrator with focal pipe and oil heat exchanger (serpentine loop) represent the external heat source to increase the temperatures of the basin water and PCM. The PCM used as a heat storage medium. The influences of high heat exchanger oil temperature on the performance of the developed solar still are experimental investigated. A comparison between a developed solar still and the convenstional solar still is carried out to evaluate the enhancement in the freshwater productivity under the same ambient conditions. The experimental results indicated that, the freshwater productivity approximately reached 10.77L/m2day for the developed solar still, while its value is recorded 4.48L/m2day for conventional solar still. The freshwater productivity of the developed solar still is 140.4% higher than that of the conventional solar still in average. Also, the daily efficiency approximately reached 25.73% for the developed solar still, while its value is recorded 46% for conventional solar still. The percentage decrease in the daily efficiency for the developed solar still about 44% compared to the convenstional solar still in average. In the present experimental work the estimated cost of one liter of freshwater productivity reaches approximately 0.1359 LE (0.0174 $) and 0.1378LE (0.0177 $) for developed solar still and conventional solar still, respectively. This results is obtained during the period from June to August 2015 under the Egyptian conditions.

Mechanical properties of a novel plymetal manufactured by laser-assisted direct metal deposition

Plymetal is the term used here to describe a composite structure where more than one solid metals are joined or pressed to gain unique set of properties. Mostly flat plates are used, which are then bonded together to form sheets for further forming processes. In this work, a novel plymetal is designed to create a structure with alternating layers of metals both in radial and in axial directions. In the radial direction, the plymetal was conceived by having a cylinder surrounded by annular structure of alternate material. In the axial direction, the centre cylindrical material is changed, followed by annular structure of alternate material. Such a plymetal is realised by laser-assisted direct metal deposition additive manufacturing technology. Two different metal powders, AISI H13 tool steel and AISI 316L stainless steel, were used to create the plymetal. The uniaxial compressive test was performed on the plymetal, and the results were compared with the individual solid structure of H13 tool steel and 316L stainless steel, also made by direct metal deposition. Young’s modulus, yield strength and yield strain of the samples were determined in compression. The dual modulus of elasticity in the region before yielding was observed in all samples. An analytical equation to calculate Young’s modulus of the plymetal based on a stiffness method was also derived. Microstructure of the plymetal was observed through optical and scanning electron microscopy, which revealed perfect bonding between the two metals and small pores with sizes less than 1 μm. It is expected that the variant of plymetal will be able to give better tuneable control on the mechanical properties for numerous applications.