This paper will presents the results of research to study to demonstrate the structural performance integrity of ferrocement composite semicircular lightweight panels for roof construction. This 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 welded wire mesh. The core of the panel was made of light weight fibrous foam concrete. The steel meshes were tied by steel wires of the two skin layers together and to act as shear connectors to transfer shear between the two ferrocement skin layers through the core in-between. The thickness of the ferrocement skin layer was 25 mm. The core material will be 70 mm thick which consisted of pyrite and ad pour 55 as lightweight aggregate. Two types of the steel mesh were used to reinforce the ferrocement skin layers. Namely: welded wire mesh and expanded metal mesh. Steel wire shear connector will be used to tie the top and bottom ferrocement skin layers through lightweight concrete in between and to provide shear reinforcement. Experimental investigation was conducted on the proposed panels. A total of 16 sandwich semicircular panels having the dimensions of 500 mm in width, and 2000 mm. in length will be tested under four lines loadings of span 1900 mm up to failure. The deformation characteristics and cracking behavior were measured and observed for each panel. The results obtained will be compared with theoretical ones by using Abaqous finite elements program version 14. The results will show that high ultimate and serviceability loads, crack resistance control, high ductility ratio 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 countiess alike
The development of expired drugs into directly applicable corrosion inhibitors for metals in acidic media, will help not only help to solve the global problem of corrosion but will also offer legal and profitable outlets for extending the cradle to grave life of those materials and eliminate the need for their illegal resale as currently happens in many developing countries such as Nigeria. The expired, biodegradable and environmental drug; Isoniazid was evaluated for corrosion inhibition capability for API5L steel in 0.5M H2SO4 environment. Electrochemical Impedance Spectroscopy (EIS) reveals a drastic drop in corrosion rate when the pulverized form of expired isoniazid drug was introduced into 0.5M sulphuric acid environment containing immersed steel samples. The impedance diagram shows the same trend (one capacitive loop); however, the diameter of this capacitive loop increases with increasing concentration. The presence of the inhibitor increases the impedance but does not change other aspects of the behaviours. EIS showed that expired isoniazid drugs inhibits corrosion in mild steel in 0.5M H2SO4 in a mixed manner. Conversely, the rate of weight loss in the environment decreased with increasing concentration of expired isoniazid in the environment. Surface Analysis shows a progressive covering and thickening of adsorbed surface layer of expired isoniazid drug film on the immersed API5L steel surface with increasing concentration of the expired drug in the acid environment. The corrosion inhibition was considered to be via a mixed mode adsorption of a layer of expired isoniazid drug molecules across active corrosion sites, gradually cutting off metal-environment contact and thus shutting the relevant corrosion process. The level and effectiveness of achievable corrosion inhibition tend to increase with increased concentration of the expired isoniazid drug in the metal-acid environment. All other evaluation methods support these conclusions.
Residual stresses are those stresses that remain in an object (in particular, in a welded component) even in the absence of external loading or thermal gradients. In some cases, residual stresses result in significant plastic deformation, leading to warping and distortion of an object. This paper investigates the prediction of residual stresses developed in shielded metal arc welding of high thickness DH32 (ASTM A131) steel plates through Finite Element Simulation and experiments. To evaluate the residual stresses in weldment, conventional strain gauges are used. These stresses are developed on the Butt joint and T joint. The geometry of the T joint and butt-welded Low Carbon Steel (ASTM A131) plates was modeled and the residual stresses were simulated using ANSYS V19.2. Sequentially coupled transient thermal-mechanical, three-dimensional finite element models were developed and the Element Birth and Death Technique was used in simulation to evaluate the stresses in simulation. The conventional strain gauges are placed in different weld zones and the obtained results from these gauges are different as per the FE results. These results show that the residual stresses obtained by prediction from the finite element method are in fair agreement with the experimental results. Based on this, it can be concluded that how far we can use the strain gauges used in the measurement of residual stresses. and also the Finite Element Model can be used to replicate and determine the expected residual stresses that would be generated before an actual welding process is carried out.
Purpose: The aim of this study was the evaluation of different plastic optical materials and determination of their behaviour in front of the eye. The study was not for clinical screening but mainly for material determination purposes, where the contrast sensitivity function is inefficient and difficult to interpret.
Methods: Thirty male and female subjects with no ocular or reported systemic abnormality were selected. Twenty-two lenses of +6.00D power, made from 8 different plastic materials following requested: specifications; were edged to round shape and decentred in order to produce a 9∆ prism in front of the subjects’ eye. Measurements of every subject were repeated four times on Bailey-Lovie and Pelli Robson charts, for each lens used in the experiment
Results: A significant decline of visual acuity in correlation to higher index plastic lenses was observed. Also we observed a similar visual acuity decline concerning aspheric design lenses, but with a little better performance than non-aspheric design lenses of the same index material.
Conclusion: The hypothesis of this work was that the higher the index the more the chromatic aberration. The conclusion is that this hypothesis is quite correct. However, the measurement of visual performance is not a very easy task. The wearer may simply experience blur through the periphery of the lens without realising the cause, and therefore the symptoms described to the optician can be confusing.
Abundantly available cassava peels waste was used to prepare porous activated carbon using a nontoxic activating agent, sodium thiosulphate (Na2S2O3). The activation was done under nitrogen flow at 8000C. The resulting porous carbon showed good surface area of 306 m2g-1. The supercapacitor electrodes fabricated from the activated carbon exhibited excellent electrochemical characteristics; showing a specific capacitance of 93.4 Fg-1 while withstanding excellent performance even up to a voltage window of 1.1V.
Introduction: Low cost refractory mixes of adequate resistance to molten glass attack is required for frit furnace lining, but when the corrosion behaviour of alumino-silicate type refractories are studied, kaolin is often neglected. Meanwhile clay is cheap in the study area and studies had shown that clays that are comprised largely of kaolinite are refractory, and are applicable for various refractory purposes. In this study, the effect of addition of zirconia and alumina to selected kaolin on its physicomechanical properties and corrosion resistance were examined.
Aims: The study is aimed at developing a corrosion resistant refractory for lining frit furnaces used in studio practice by fortifying a locally available kaolin in Nigeria know refractory materials.
Study Design: The experimental design in which the effect of percentage addition of alumina and zircon on the sintering properties and corrosion resistance of base kaolin were measured against the desired properties of the resultant bodies.
Methodology: The clay mineralogical analysis was conducted using XRD. The refractoriness was measured by the pyrometric cone equivalence (PCE) method. The effects of varying percentage additive refractory material on the sintering properties of bodies formulated and sintered at 1300 oC were assessed using the ASTMC20 00 Standard test method. The corrosion resistance of the bodies was assessed using the crucible (slag cup) method.
Results: Results indicated that the clay was predominantly kaolinite. The addition of alumina increases the porosity of the mix. The stabilized zircon increased the specific gravity the most. It increased the bulk density at both 5% and 10 % addition but decreased at 15% addition. The sample mix which contained 10% stabilized zircon and 5% alumina shows appreciable resistance to corrosion by the molten frit.
Conclusion: This study confirms that clay that is predominantly composed of kaolinite is a potential base material for composing refractory lining for a fritting furnace.
The stability of polymer-based organic solar cells is a crucial factor for the commercialization of solar cells. Testing of organic-inorganic nanostructures in polymer solar cells (PSCs) would be a better option to minimize the drawbacks due to the short lifetime. In this study, PSCs were fabricated incorporating gold (Au) and copper oxide (CuO) nanoparticles(NPs) in the active layer of the device. Bulk heterojunction blend of regioregular poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) was used as the active material and poly-(4,3-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was used as the hole transport layer (HTL) in fabrication. The electrical parameters of the fabricated devices showed a significant improvement after incorporating both CuO and Au NPs with the highest power conversion efficiency (PCE) of 3.139%. The relevant short circuit current (Jsc), open-circuit voltage (Voc) and fill factor (FF) were 7.206 mAcm-2, 0.66 V, and 66 respectively. The stability measurements were obtained for a 20-day period. These measurements are clearly indicated that the CuO NPs have a significant influence on the stability of the PSCs.
In the world of nanotechnology, a green approach for the synthesis of nanoparticles is becoming a focal point of modern research. Being environmentally friendly, biosynthesized nanoparticles are very stable and exhibit variations in their size, shape, strength, surface area and other specific properties that can easily be used in planned applications. However, a lot of metallic nanoparticles are available, but on the basis of distinctive physical, biological and chemical features silver, copper, zinc, iron and gold nanoparticles attract more interest. The majority of plants and microorganisms are commonly used for the synthesis of nanoparticles, however as a renewable solution, the synthesis of nanoparticles has been an option to overcome the other method’s deficiencies. Since the green approach to nanoparticles' synthesis is more robust, their synthesis is too rapid. Different plants have different biomolecules available, hence increasing the rate of stabilization and reduction of synthesized nanoparticles due to their stabilization and reduction agents. The focus of this study is on the green synthesis strategies of copper, zinc, silver, gold, iron and cobalt nanoparticles. This review paper covers various metallic nanoparticles synthesized on green basis arranged on alphabetical manner and other characteristics viz. shape of nanoparticles, size of nanoparticles, and name of the plant part under observation and finally year of paper publication.
Large quantities of non-biodegradable waste effluents pollutants discharged globally have remained very challenging to adsorption removal or photodegradation treatment. They introduce a significant decrease in water flux, expensive treatment costs, and some with carcinogenic potential. Several options of different adsorbents from natural, synthetic, and agricultural waste have been applied in the removal of numerous contaminants from the effluent matrix without a panacea. There is therefore the research need in finding cheap, readily available, and cost-efficient naturally occurring materials for effluent treatment. Periwinkle shell and periwinkle ash is an emerging material among animal shells with promising adsorption potentials and photocatalytic capabilities for effluent treatment. A well-established background about the periwinkle shells and periwinkle ash was presented. Studies on periwinkle composites (PCM) in adsorption and photocatalysis, showed effectiveness in both neutral, acidic, and alkaline mediums in the removal of wastewater effluents. PCM possesses a large surface area, high porosity, and presence of functional groups on the surface of the activated material which denotes a promising low-cost material for the production of adsorbent/photocatalyst of high efficiency in the removal of waste effluents. In the last section, the outlook pointed out what should likely be the next steps required to advance periwinkle composite materials in waste effluent treatments.