Mesh Layers Research Articles

Enterosgel role in neurodegenerative changes in the retina rats under the influence of Cr (VI) - induced retinopathy by study morphological changes in dynamic

Chromium galvanic production have leaded to biosphere pollution. Therefore advisable to study of role in the neurodegenerative development in retinal diseases under experimental conditions. The aim is to study the Enterosgel effect on morphological changes in rats retina with Cr(VI) – induced retinopathy. Materials and methods. An experimental study had carried out on 72 outbred white male rats. The rats had divided into 3 groups: I – control group of intact rats (n = 24). Control rats were received drinking water, II group – rats (n = 24), were received drinking water with Cr (VI) (K2Cr2O7) – 0.02 mol/L, III group – animals (n = 24) were received drinking water with K2Cr2O7– 0.02 mol/L and hydrogel methylsilicic acid (Enterosgel) at a dose of 0.8 mg/kg per day as a corrector. The animals had been decapitated under ether anesthesia. The retina had been studied on days 20, 40 and 60 of the experiment. Morphologically and morphometrically they had analyzed. Results. According to histological studies, it has proved that Cr (VI) causes dystrophic and degenerative changes in all rats retina layers. They increase as the duration of the experiment. The use of Enterosgel as a corrective therapy showed positive results in restoring the morphological structure of rats retina. After Enterosgel 20 days using as a corrector of Cr (VI) exposure, there is a barely noticeable swelling of the outer and inner nuclear layers. Other layers of the retina, morphologically, look undamaged. Forty days Enterosgel treatment have outer and inner nuclear layer edema of retina of animals persists but does not increase. It is easy noticeable swelling of the outer and inner layers of mesh, but no signs of damage processes of cell populations nuclear layers. State ganglionic layer and nerve fiber layer entirely satisfactory. These pathological changes are not critical. After 60 days from the beginning of loading of Cr (VI) and application of Enterosgel in the retina of rats there are initial degenerative changes in the photosensory layer. Cystic dilated outer segments of rods and cones were visible throughout, and areas of their fragmentation were observed. Ganglion neurons are not damaged, but their axons appear somewhat thickened and fluffy. But in general, the typical structure of the retina is preserved. Conclusions. Chromium-induced toxicity in rats is characterized by pronounced histological and morphometric changes and retinal thickness, which appear after 20 days, increase by 40 days and acquire maximum transformations after 60 days of the experiment. The use of Enterosgel improves picture morphological structures of the retina in rats under the influence of Cr (VI). The changes were expressed on days 20 and 40, which indicates the presence of protective properties for the retina

Tailoring catalyst layer interface with titanium mesh porous transport layers

Tailoring the catalyst layer interface is paramount for high performance electrochemical energy conversion, from fuel cells to carbon dioxide electrolyzers. Here, we tailored the catalyst layer (CL) interfacial contact in a polymer electrolyte membrane (PEM) water electrolyzer with bilayer titanium mesh porous transport layers (PTLs). In contrast to typical commercial PTL materials, ohmic losses dominated the overpotentials of a PEM electrolyzer with bilayer mesh PTLs, contributing up to 73% of the overall overpotential (at a current density of 1 A/cm2). Tailoring the mesh opening size (from 1.16 mm to 0.20 mm) led to a 56% reduction in ohmic losses due to the enhanced contact between the mesh PTL and the CL. Non-negligible mass transport losses were attributed to gas pooling at the PTL/CL interface when the pore width exceeded the pore height. However, when the pore height exceeded the pore width, significantly higher mass transport losses were observed, which we attributed to complete gas filling of the pores. Additionally, we found that bilayer mesh PTLs with pore size gradients are susceptible to delamination at the CL/PTL interface due to the misalignment of mesh layers.

Investigation of steel wire mesh reinforcement method for 3D concrete printing

3D concrete printing has received widespread attention and been developed for an increasing number of applications. However, a major challenge facing this technology is an effective way to introduce reinforcement into continuously deposited cementitious material. In this study, different layers of steel wire meshes (SWM) are employed to reinforce the 3D printed structures to improve mechanical capacities. Both destructive (bending, compression and splitting) and non-destructive (using electro-mechanical impedance) tests are employed to characterize the impact of this reinforcement method. The damage accumulation process is measured through the smart PZT patches based on the electro-mechanical impedance method. The results indicate that reinforced 3D-printed components with SWM change their failure modes from brittle to ductile. The peak loads are increased by 59.2–173.3% and the deflection capacity can be increased by more than 11 times than the non-reinforced one. Different mechanical responses of print and cast samples under compression are studied. The splitting tensile strength of wire mesh reinforced concrete is also measured, which is 43.7% higher than the non-reinforced sample. The calculating methods of the cracking moment and ultimate moment of steel wire mesh reinforced 3D printed concrete are presented. Comparison between the calculated and the experimental results verifies the effectiveness in predicting the ultimate moment. Experimental results show that it is feasible and effective to employ steel wire mesh for strength and toughness enhancement of 3D printed structures.

Optically transparent and very thin structure against electromagnetic pulse (EMP) using metal mesh and saltwater for shielding windows

An electromagnetic pulse (EMP) with high energy can damage electronic equipment instantly within a wide range of thousands of kilometers. Generally, a metal plate placed inside a thick concrete wall is used against an EMP, but it is not suitable for an EMP shielding window, which requires not only strong shielding effectiveness (SE) but also optical transparency (OT). In this paper, we propose a very thin and optically transparent structure with excellent SE for EMP shielding window application. The proposed structure consists of a saltwater layer held between two glass substrates and two metal mesh layers on the outside of the glass, with a total thickness of less than 1.5 cm. The SE and OT of the structure are above 80 dB and 45%, respectively, which not only meet the requirement of EMP shielding for military purposes but also retain the procedure of good observation. Moreover, the OT of the structure can be significantly improved using only one metal mesh film (MMF) layer, while the SE is still maintained high to satisfy the required SE for home applicants. With the major advantages of low cost, optical transparency, strong SE, and flexible performance, the proposed structure can be considered a good solution for transparent EMP shielding windows.

Experimental investigation of shear connector behaviour in composite beams with metal decking

Presented are experimental results from 24 full-scale push test specimens to study the behaviour of composite beams with trapezoidal profiled sheeting laid transverse to the beam axis. The tests use a single-sided horizontal push test setup and are divided into two series. First series contained shear loading only and the second had normal load besides shear load. Four parameters are studied: the effect of wire mesh position and number of its layers, placing a reinforcing bar at the bottom flange of the deck, normal load and its position, and shear stud layout. The results indicate that positioning mesh on top of the deck flange or 30 mm from top of the concrete slab does not affect the stud\' s s strength and ductility. Thus, existing industry practice of locating the mesh at a nominal cover from top of the concrete slab and Eurocode 4 requirement of placing mesh 30 mm below the stud\' s head are both acceptable. Double mesh layer resulted in 17% increase in stud strength for push tests with single stud per rib. Placing a T16 bar at the bottom of the deck rib did not affect shear stud behaviour. The normal load resulted in 40% and 23% increase in stud strength for single and double studs per rib. Use of studs only in the middle three ribs out of five increased the strength by 23% compared to the layout with studs in first four ribs. Eurocode 4 and Johnson and Yuan equations predicted well the stud strength for single stud/rib tests without normal load, with estimations within 10% of the characteristic experimental load. These equations highly under-estimated the stud capacity, by about 40-50%, for tests with normal load. AISC 360-16 generally over-estimated the stud capacity, except for single stud/rib push tests with normal load. Nellinger equations precisely predicted the stud resistance for push tests with normal load, with ratio of experimental over predicted load as 0.99 and coefficient of variation of about 8%. But, Nellinger method over-estimated the stud capacity by about 20% in push tests with single studs without normal load.

Structural Behavior of Reinforced Concrete Slabs Containing Fine Waste Aggregates of Polyvinyl Chloride

In several areas worldwide, the high cost and shortage of natural resources have encouraged researchers and engineers to explore the serviceability and feasibility of using recycled aggregates in concrete mixtures, substituting a normal aggregate percentage. This technique has advantages for the environment by reducing the accumulation of waste materials, while it impacts the fresh and hardened concrete performances, reducing workability, flexural strength, compressive strength, and tensile strength. However, most studies have investigated the influence of replacing normal aggregates with waste aggregates on the concrete mechanical properties without examining the impact of using waste materials on concrete structural performance. The aim of this research is to investigate the effect of replacing 75% of sand volume with polyvinyl chloride (PVC) fine waste aggregates on the performance of reinforced concrete slabs. Different thicknesses of the concrete layer (0%, 25%, 50%, and 100% of slab thickness) containing PVC fine waste aggregates are investigated. Based on the reductions in the toughness and flexural strength capacity due to incorporating 75% PVC fine aggregate dosage, two approaches are used to strengthen the slabs with 75% PVC fine aggregates. The first approach is adding polyvinyl alcohol (PVA) to the PVC fine aggregate concrete mix to improve the mechanical properties of the concrete. The PVA increases the water viscosity in the concrete, which reduces the dry out phenomenon. With that said, the PVA modified fresh concrete does enable the use of the limits of the PVC fine aggregate dosage for high dosage plastic aggregate concrete. The second approach uses two fiber wire mesh layers as an additional reinforcement in the tested slab. Results show that the PVC-30 slab exhibits an 8% decrease in total area toughness compared to the control (Con) slab, while for PVC-60 slab toughness, the total area shows 26% less. Additionally, the inclusion of PVA in the concrete with 75% PVC plastic waste fine aggregate replacement greatly influences the pre-and post-cracking ductile performance among other slabs, representing that using PVA with higher contents might increase the flexural performance. Therefore, due to the substantial effect of PVA material on the concrete flexural performance, it is proposed to utilize PVA with an optimum PCV fine aggregate dosage in the concrete mix.

Sustainable utilization of industrial wastes for the cleaner production of ferrocement structures: A comprehensive review

Creative development of ferrocement technology in the construction industry has enhanced dynamically due to its faster construction, lighter weight, higher strength, durability and economical advantages than the reinforced concrete structures. The use of smaller diameter closely spaced mesh layers which is uniformly distributed throughout the cross section improved the moment of resistance, deflection and ductility of the ferrocement members. To achieve the environmental friendliness and sustainability in the durable ferrocement technology, this paper aims to provide a comprehensive implication reviewed from the previous research works carried out to explore the application of industrial waste materials in the ferrocement construction. Influence of various industrial waste materials on the behaviour of both mortar and meshing reinforcement were discussed separately. The optimum level replacement, effect on the structural behaviour and the suitability in the various environmental conditions were inferred. For instance, Ground Granulated Blast furnace Slag (GGBS) could be utilized as a binder at the maximum of 50% by weight, where as the use of metakaolin in ferrocement construction is optimum at 15% by weight as further addition caused the undesirable effect on the mechanical properties due to the delay in hydration process and inefficient filler effect. Grain size modified nano industrial wastes like nano silica and nano fly ash resulted in improved mechanical and micro structural behaviour of ferrocement products due to its nano filling effect. The use of nano fly ash was found to be successful as nano binder to the maximum of 10% which is not possible in case of other costlier nano materials like nano silica, alumina, titanium oxide, etc. The major issues of corrosion and chemical attack in ferrocement mesh were easily solved by the implementation of high molar geopolymer mortar which also resulted in cleaner and greener production of ferrocement products.

Modulating a 2D heterointerface with g-C3N4 mesh layers: a suitable hetero-layered architecture for high-power and long-life energy storage

2D heterointerfaces are modulated with mesh-like g-C3N4 layers, which aim at developing a suitable hetero-layered architecture for high-performance energy storage devices.

Experimental investigation of air pressure drops on different mesh layers using air filter performance test rig

Abstract This paper focuses on the experimental investigation of pressure drops obtained on different mesh layers setup with the use of Air Filter Performance test rig according to EN 61591 and verification of specially designed test piece and results in quality. Two different mesh sizes and a combination of both were investigated during the experiment. Pressure drops on filters setups were measured, plotted against flow rate, and compared. Test outcome proves that test piece was designed appropriately and pressure drop results obtained on filter setups are aligned with the theory.

Affordable housing: Cost effective construction materials for economically weaker section

In any populous country shelter for everyone is an emerging need. This leads to a concept of affordable housing for developing countries, especially for the Economically Weaker Section (EWS). An experimental investigation has been made with an aim to suggest a cost effective construction technique in order to build an affordable house for EWS people. In this attempt, various cost effective materials such as EPS (Expanded polystyrene), coconut shell, Foundry sand, Fly ash were used. A separate concrete mix proportion was designed and adopted for every cost effective material used in this work. The slab panel with the size of1.5′×2′ and their companion test specimens were also cast and tested. Three different types of reinforcements were adopted in this investigation such as Geogrid, Mild steel rod of 6 mm diameter and two layer of wire mesh having 1 mm diameter with 10 mm spacing on both the directions were adopted as three different reinforcements in this investigation. Finally, 15 numbers of slab panels were tested for gradually increased uniformly distributed load with simply supported condition. The cost analysis to cast every slab was made and obtained an optimum cost effective material with high strength.

Structural behavior of concrete walls reinforced with ferrocement laminates

The present work focuses on experimental and numerical performance of the ferrocement RC walls reinforced with welded steel mesh, expanded steel mesh, fiber glass mesh and tensar mesh individually. The experimental program comprised twelve RC walls having the dimensions of 450 mmx100 mmx1000 mm under concentric compression loadings. The studied variables are the type of reinforcing materials, the number of mesh layers and volume fraction of reinforcement. The main aim is to assess the influence of engaging the new inventive materials in reinforcing the composite RC walls. Non-linear finite element analysis; (NLFEA) was carried out to simulate the behavior of the composite walls employing ANSYS-10.0 Software. Parametric study is also demonstrated to check out the variables that can mainly influence the mechanical behavior of the model such as the change of wall dimensions. The obtained numerical results indicated the acceptable accuracy of FE simulations in the estimation of experimental values. In addition, the strength gained of specimens reinforced with welded steel mesh was higher by amount 40% compared with those reinforced with expanded steel mesh. Ferrocement specimens tested under axial compression loadings exhibit superior ultimate loads and energy absorbing capacity compared to the conventional reinforced concrete one.

Mesh layer jamming: Development of a variable-stiffness sheet that can cover curved surfaces

Mesh layer jamming: Development of a variable-stiffness sheet that can cover curved surfaces

Study Smart-layer effect on the physical and mechanical characteristics of the samples from polymer composite materials under quasi-static loading

Currently, developments of the so-called Smart-constructions are relevant as they enable a real-time monitoring of changes in required values. Smart designs are widely used in the construction, automotive and aerospace industries. Technologies of creating products from polymer composite materials make it possible to introduce various sensors directly into the structure of a material, thereby create systems monitoring the state of structures. The most recommended for such implementation are fiber-optic sensors, which have a number of advantages over other sensors (luminescent, strain gauge, piezoelectric ones). However, when introducing the fiber-optic sensors, there is a number of difficulties, which are primarily associated with fragility of the optical fiber and lead to the breakdown of fiber-optic lines. As a result, it is necessary to develop a Smart-layer that will protect the optical fiber leads and will not significantly change the physical and mechanical characteristics. This paper aims to determine the stiffness and strength characteristics of samples made of polymer composite materials: reference samples, samples with embedded fiber-optic sensors, samples with embedded Smart-layers. In this work, a Smart-layer is understood as a coating that protects the fiber-optic sensors at the stage of implementation into a structure. The paper considers the following configurations of the Smart-layer: polymer reinforced mesh, polyamide and polyurethane layer. We analyzed and compared the influence of the embedded optical fiber and various configurations of the Smart-layer in the composite structure on the physicomechanical characteristics of the samples obtained under quasi-static loading (tension, compression, and interlayer shear). For a more detailed analysis of using the fiber-optic sensors and various configurations of the Smart-layer, the corresponding loads were simulated to assess their mechanical behavior. Based on the obtained physical and mechanical characteristics, a specific configuration of the Smart-layer was selected and justified for further researches.

Structural Behavior of Light Weight Ferrocement Walls

This paper presents the experimental results of research to develop ferrocement sandwich panels for use as wall bearing units. The proposed panels are lighter in weight relative to the conventional reinforced concrete panels The sandwich panels consisted of two thin ferrocement layers reinforced with one or two layers of closely spaced galvanized welded wire mesh and expanded steel mesh. The core of the panel was made of light weight brick. Steel wires were used to tie the steel meshes of the two skin layers together and to act as shear connectors to transfer shear between the two ferrocement skin layers. These steel wires were embedded in the mortar joints of the brick. The thickness of the ferrocement skin layer was 10mm when single layer of wire mesh was used and 15mm when two layers of mesh reinforcement were used. Experimental investigation was conducted on the proposed panels. A total of 10 sandwich panels Having the dimensions of 600mm width and 700mm height were tested under compressive loadings until failure. The deformation characteristics and cracking behavior were measured and observed for each wall panel. The results showed that high ultimate and serviceability loads, crack resistance control, high ductility, and good energy absorption properties could be achieved by using the proposed panels. This could be of great construction advantages for both developed and developing counties.

Design of a Wide Planar Waveguide Antenna for UHF Near-Field RFID Reader With High Reading Rate

UHF near-field RFID reader antenna based on leaky waveguide is proposed and the performance is evaluated using numerical simulation and experiment. In order to suppress the standing wave along transverse direction, a pair of notches is placed on the transverse edge of the mesh layer of the planar waveguide. Diversity operation by switching impedance of the end terminal of the planar waveguide antenna is also introduced to suppress the standing wave effect along longitudinal direction. Numerical simulation and experiment show that the near-field null lines parallel to the longitudinal direction is almost removed by the presence of the notches and the distribution of the field strength becomes almost uniform because of the utilization of the switching diversity. It is demonstrated that the reading performance of the commercial RFID tags is greatly improved by using the proposed RFID reader antenna with the diversity operation of termination impedance.

High Detectivity Ammonia Gas Sensor of Pentacene Based Organic Material with OXIDE MESH

Ammonia gas sensing properties of pentacene based organic gas sensor fabricated by thermal evaporation method on amorphous oxide semiconductor (a-SiInZnO) mesh. The amorphous oxide semiconductor mesh layer was fabricated by RF sputtering and conventional photolithography. Insertion of a dense mesh layer has been found to significantly improve gas sensing properties. In the case of a conventional pentacene thin film, the SEM image analysis resulted in a uniform surface. This means that ammonia gas cannot be adsorbed well on the surface. The insertion of the mesh layer improves the surface volume ratio of the organic thin film and induces more ammonia gas to be adsorbed on the pentacene surface. As a result, it was confirmed that even when the ammonia gas concentration was 5 ppm or less, the detection rate was higher than that of a conventional pentacene thin film. It is expected to be applied to various high-sensitivity organic-based gas sensors.

The study of the strength of materials printed using additive technology and comparing their properties with the data obtained using the CAE-system

The paper presents the results of an experimental study of bending tests of the samples printed by means of additive technology according to various schemes for filling cells and constructing a frame of plates, as well as their positioning on the printer table. It has been found that to increase the strength of the printed material during bending, it is advisable to create mesh layers with large strength properties in the layers of the parts that are opposite to the applied force, since it is the lower layer that undergoes stretchig, while the upper layer is compressed. This conclusion opens up the possibility of creating 3D-printed samples with variable strength properties in certain directions. Test samples were created with the formation of the borders consisting of 1, 2, 3 and 4 threads. The analysis of the experimental data makes it possible to note that the samples having 3 and 4 threads are similar in their strength characteristics. That suggests that for optimal industrial use it is enough to create structures with 2, 3 threads of the boundary shell. The scientific substantiation of the reason for the difference in the strength parameters of the printed material depending on its internal structure and positioning on the printer table was further developed. Based on the results of this work, we can conclude that modelling the strength properties of objects created by 3D-printing is possible, provided that the enterprise creates a library of the correction factors obtained based on the analysis of statistical information. In Ukraine, additive technologies are not yet the subject of the first choice. Therefore, the development at the Department of Mechanical Engineering Technology of the Priazovsky State Technical University and the manufacture on a 3D-printer of the «Lubricating» Gear part of a cylindrical gearbox is a pioneering solution in the heavy engineering industry. The obtained Implementation Act is the result of the first stage of promising work, for the continuation of which both production stands and engineering training, which includes the widespread use of CAE-systems, are necessary. It should be noted that even high-level, generally accessible CAE-systems do not yet have separate applications for working with the parts created using additive technology, which creates the need to create user-developed macros for this purpose

Axial Compressive Performance of Corroded Concrete Columns Strengthened by Alkali-Activated Slag Ferrocement Jackets

Chloride-induced corrosion of reinforcement has endangered the safety of reinforced concrete (RC) structures. It is, therefore, necessary to strengthen the corroded RC members to ensure structural safety. This study aims to investigate the effectiveness of alkali-activated slag (AAS) ferrocement jackets in strengthening corroded RC columns. AAS ferrocement specimens with various layers of stainless steel wire mesh (SSWM) were subjected to direct tensile tests. Square RC columns suffered artificially accelerated corrosion and were subsequently strengthened by AAS ferrocement jackets. Axial compressive tests were conducted on the column specimens. Experimental results have shown that corroded specimens suffer severe losses in loading capacity up to 46% as compared with the control one. Volume fraction of transverse SSWM (ρv) plays primary role in loading capacity and ductility of ferrocement and its confinement on column specimens. Ferrocement with ρv of 0.266% can rehabilitate loading capacity of specimens with corrosion degrees of 8.9% and 18.3% by 37% and 46%, respectively. Corroded specimen strengthened by ferrocement with ρv of 0.532% achieves approximately two times the ductility than the one without strengthening. Ferrocement jackets provide better and uniform confinement to core concrete than new stirrups. Analytical models are proposed to predict tensile strength of AAS ferrocement and loading capacity of specimens strengthened by ferrocement jackets. The prediction is in good agreement with experimental results.

A study on flexural behavior of geopolymer mortar based ferrocement

Abstract The aim of this work is to investigate the presence of ferrocement mesh in geopolymer mortar and the obtained results are compared with cement mortar prisms. GGBS and class F Fly ash are used as binders in geopolymer mortar and the alkaline activator solution (sodium hydroxide + sodium silicate) with 8 M sodium hydroxide solution having an alkaline modulus (Na20/SiO2) of 0.6 is used. Three different mixes i.e., Binder: Fine aggregate ratio of 1:1, 1:1.5, 1:2 and different layers of wire mesh (i.e., 0layers, 1layer, 2layers, 3layers) were considered in this study. Prisms of size 500 mm*100 mm*25 mm and cubes of size 100 mm*100 mm*100 mm were cast with cement mortar and geopolymer mortar. The obtained results indicate that increase in layers of wire mesh had a positive effect on flexural strength and toughness. Both cement mortar and geopolymer mortar specimens showed nearly same flexural strength when more layers of wire mesh are present.

STRENGTHENING OF REINFORCED CONCRETE SQUARE COLUMNS BY MEANS OF FERRO CEMENT JACKET

This paper presents an experimental investigation to clarify the behaviour of reinforced concrete square columns strengthened using ferrocement jacket. Strengthening using ferrocement jacket is relatively a new technique, which has a high strength/weight ratio, good resistance to cracking and impact loading, acceptable resistance to fire, and more resistance to corrosion than traditional materials. Ten reinforced concrete short columns with nominal cross-sectional dimensions of 200 × 200 mm with a total length of 1200 mm were cast and tested under axial loading until failure. The main parameters in this study were the number of layers of wire mesh, type of wire mesh, and the cement mortar strength. The results showed the effectiveness of the ferrocement jacket in improving the column capacity and reducing the vertical and lateral deformation. The results from the experiment were compared with the theoretical results obtained from the modified ECP 203 and modified ACI 318 equation codes.