A STUDY ON DIFFERENT PROPERTIES OF CEMENT MORTAR BY PARTIAL REPLACEMENT OF FINE AGGREGATE WITH BOTTOM ASH

This paper consists of the results of an experimental research on the effect of bottom ash as partial replacement of natural sand on the properties of cement mortar. The experimental works were carried out by replacement of fine aggregate with varying percentages of bottom ash i.e. 15%, 20%, 25% and 30%. As the microstructure of mortar matrix changes with varying water cement ratio, the w/c was kept constant i.e. 0.45.Mortar cubes of 70.6mm×70.6mm×70.6mm were casted and vibrated on an electrically operated vibrator. Then various tests including compressive strength, water permeable porosity (apparent porosity), percentage of water absorption, sorptivity were performed on mortar cubes replaced with bottom ash. The results were compared with the results of control mix and all the tests were performed at 3, 7, 28, 56 and 90 days. Based on the results, it is concluded that fine aggregates can be replaced up to 20% with bottom ash in cement mortar.

A STUDY ON DIFFERENT PROPERTIES OF CEMENT MORTAR BY PARTIAL REPLACEMENT OF FINE AGGREGATE WITH BOTTOM ASH

This paper consists of the results of an experimental research on the effect of bottom ash as partial replacement of natural sand on the properties of cement mortar. The experimental works were carried out by replacement of fine aggregate with varying percentages of bottom ash i.e. 15%, 20%, 25% and 30%. As the microstructure of mortar matrix changes with varying water cement ratio, the w/c was kept constant i.e. 0.45.Mortar cubes of 70.6mm×70.6mm×70.6mm were casted and vibrated on an electrically operated vibrator. Then various tests including compressive strength, water permeable porosity (apparent porosity), percentage of water absorption, sorptivity were performed on mortar cubes replaced with bottom ash. The results were compared with the results of control mix and all the tests were performed at 3, 7, 28, 56 and 90 days. Based on the results, it is concluded that fine aggregates can be replaced up to 20% with bottom ash in cement mortar.

Analysis of the forced convection of two-phase Ferro-nanofluid flow in a completely porous microchannel containing rotating cylinders

In the present work, the forced convection of nanofluid flow in a microchannel containing rotating cylinders is investigated in different geometries. The heat flux applied to the microchannel wall is 10,000 W m−2. The effects of Reynolds number, the volume fraction of nanoparticles, and the porosity percentage of the porous medium are investigated on the flow fields, temperature, and heat transfer rate. Reynolds number values vary from Re = 250–1000, non-dimensional rotational velocities 1 and 2, respectively, and volume fraction of nanoparticles 0–2%. The results show that increasing the velocity of rotating cylinders increases the heat transfer; also, increasing the Reynolds number and volume fraction of nanoparticles increases the heat transfer, pressure drop, and Cf,ave. By comparing the porosity percentages with each other, it is concluded that due to the greater contact of the nanofluid with the porous medium and the creation of higher velocity gradients, the porosity percentage is 45% and the values of are 90% higher than the porosity percentage. Comparing porosity percentages with each other, at porosity percentage 90% is greater than at porosity percentage 45%. On the other hand, increasing the Reynolds number reduces the entropy generation due to heat transfer and increases the entropy generation due to friction. Increasing the volume fraction of nanoparticles increases the entropy generations due to heat transfer and friction.

Piezoelectric and Electromechanical Characteristics of Porous Poly(Ethylene-co-Vinyl Acetate) Copolymer Films for Smart Sensors and Mechanical Energy Harvesting Applications

This paper investigates energy harvesting performances of porous piezoelectric polymer films to collect electrical energy from vibrations and power various sensors. The influence of void content on the elastic matrix, dielectric, electrical, and mechanical properties of porous piezoelectric polymer films produced from available commercial poly(ethylene-co-vinyl acetate) using an industrially applicable melt-state extrusion method (EVA) were examined and discussed. Electrical and mechanical characterization showed an increase in the harvested current and a decrease in Young’s modulus with the increasing ratio of voids. Thermal analysis revealed a decrease in piezoelectric constant of the porous materials. The authors present a mathematical model that is able to predict harvested current as a function of matrix characteristics, mechanical excitation and porosity percentage. The output current is directly proportional to the porosity percentage. The harvested power significantly increases with increasing strain or porosity, achieving a power value up to 0.23, 1.55, and 3.87 mW/m3 for three EVA compositions: EVA 0%, EVA 37% and EVA 65%, respectively. In conclusion, porous piezoelectric EVA films has great potential from an energy density viewpoint and could represent interesting candidates for energy harvesting applications. Our work contributes to the development of smart materials, with potential uses as innovative harvester systems of energy generated by different vibration sources such as roads, machines and oceans.

Fabricating Lattice Structures via 3D Printing: The Case of Porous Bio-Engineered Scaffolds

Over time, the fabrication of lattice, porous structures has always been a controversial field for researchers and practitioners. Such structures could be fabricated in a stochastic way, thus, with limited control over the actual porosity percentage. The emerging technology of 3D printing, offered an automated process that did not require the presence of molds and operated on a layer-by-layer deposition basis, provided the ability to fabricate almost any shape through a variety of materials and methods under the umbrella of the ASTM terminology “additive manufacturing”. In the field of biomedical engineering, the technology was embraced and adopted for relevant applications, offering an elevated degree of design freedom. Applications range in the cases where custom-shaped, patient-specific items have to be produced. Scaffold structures were already a field under research when 3D printing was introduced. These structures had to act as biocompatible, bioresorbable and biodegradable substrates, where the human cells could attach and proliferate. In this way, tissue could be regenerated inside the human body. One of the most important criteria for such a structure to fulfil is the case-specific internal geometry design with a controlled porosity percentage. 3D printing technology offered the ability to tune the internal porosity percentage with great accuracy, along with the ability to fabricate any internal design pattern. In this article, lattice scaffold structures for tissue regeneration are overviewed, and their evolution upon the introduction of 3D printing technology and its employment in their fabrication is described.

Sol–gel deposited xerogel, aerogel and porogen based porous low-k thin films: A comparative investigation

Low dielectric constant (Low-[Formula: see text]) films are used as inter layer dielectric (ILD) in nanoelectronic devices to reduce interconnect delay, crosstalk noise and power consumption. Tailoring capability of porous low-[Formula: see text] films attracted more attention. Present work investigates comparative study of xerogel, aerogel and porogen based porous low-[Formula: see text] films. Deposition of SiO2 and incorporation of less polar bonds in film matrix is confirmed using Fourier Transform Infra-Red Spectroscopy (FTIR). Refractive indices (RI) of xerogel, aerogel and porogen based low-[Formula: see text] films observed to be as low as 1.25, 1.19 and 1.14, respectively. Higher porosity percentage of 69.46% is observed for porogen-based films while for shrinked xerogel films, it is lowered to 45.47%. Porous structure of low-[Formula: see text] films has been validated by using Field Emission Scanning Electron Microscopy (FE-SEM). The pore diameters of porogen based annealed samples were in the range of 3.53–25.50 nm. The dielectric constant ([Formula: see text]) obtained from RI for xerogel, aerogel and porogen based films are 2.58, 2.20 and 1.88, respectively.

Kualitas Batugamping Gorontalo Sebagai Reservoir Air Tanah Berdasarkan Analisis Jenis Porositas

The potential of limestone in Gorontalo City is not only the use of industrial minerals but also its availability as a reservoir of groundwater reservoirs. The availability of groundwater is the main focus in preserving the environment. For this reason, this research focuses on the quality of limestone reservoirs by analyzing limestone porosity. The purpose of this study was to determine the average porosity percentage, porosity type and porosity quality both semi-quantitative and qualitative. In order to achieve these objectives, two methods are used namely the field survey method and petrographic analysis. The results showed the average percentage of porosity quality of limestone as a reservoir of groundwater in the excellent category with the type of porosity is fracturing and growing (vugular).

Characterization and Monitoring of Titanium Bone Implants with Impedance Spectroscopy

Porous titanium is a metallic biomaterial with good properties for the clinical repair of cortical bone tissue, although the presence of pores can compromise its mechanical behavior and clinical use. It is therefore necessary to characterize the implant pore size and distribution in a suitable way. In this work, we explore the new use of electrical impedance spectroscopy for the characterization and monitoring of titanium bone implants. Electrical impedance spectroscopy has been used as a non-invasive route to characterize the volumetric porosity percentage (30%, 40%, 50% and 60%) and the range of pore size (100–200 and 355–500 mm) of porous titanium samples obtained with the space-holder technique. Impedance spectroscopy is proved to be an appropriate technique to characterize the level of porosity of the titanium samples and pore size, in an affordable and non-invasive way. The technique could also be used in smart implants to detect changes in the service life of the material, such as the appearance of fractures, the adhesion of osteoblasts and bacteria, or the formation of bone tissue.

Resin Mould for Ceramic Slip Rotary Moulding (CSRM) System

A type of porous resin was proposed to replace the existing plaster mould for Ceramic Slip Rotary Moulding (CSRM) system. The proposed resin is often used in high pressure casting of ceramic sanitary ware and table ware. The effect of resin mould in terms of mechanical strength (flexural properties), porosity percentage and percentage of water absorption as well as moulding process were recorded and compared with previous studies of plaster mould. Five (5) samples of porous resin were prepared according to ASTM 790 for flexural test and ASTM D570 for water absorption test. To determine the porosity percentage, mercury porosimeter test was conducted. The result shows that higher the water plaster ratio resultant in higher porosity percentage and water absorption. The result showed that, the proposed porous resin has great potential in replacing plaster mould as mould material for CSRM system. The mould has a uniform open pore to enable the filtration process to take place within the mould and the slip and has a great mechanical strength. However, porous resin is still a semi-permanent mould with definite service life.

Fabrication Study of Cu-C-Ni for EDM Electrode by a Sintering Technique

The aim of this research was to study the feasibility for applications related to powder metallurgy in EDM electrode fabrication by combination of the percentage Cu-C-Ni element. The experiment was performed by comparing preliminary distribution results of particle size before and after the grinding of metal powders. The work-piece was pressed at a pressure of 200 Psi using a uniaxial press machine. The pressed green compact work-piece was then baked in a furnace. The gas inside the furnace that was used to control the temperature during the cold press procedure had a mixture gas ratio between argon and hydrogen of 95:5 (common grade) at 1030 oC and a soaking time of one hour. The results were examined by comparing the electric resistivity property, apparent density, bulk density as well as the porosity percentage inside the work piece material. The results revealed that the optimum combination of percentage Cu-C-Ni element was Cu92-C3-Ni5 (%wt), leading to the satisfactory Copper distribution in most of the structure. The size of sub sieve powder after grinding was found to be 22-31 micron with an electric resistivity of 1.45829E-05 k-ohm*cm. The minimum porosity percentage was found to be 2.19 %. Therefore, the element properties were found to be suitable for using as an electrode in EDM work when compared to that of the electrode prototype (EDM C3).