Published: Aug 9, 2021

Brine sludge waste from a Chlor-alkali industry: characterization and its application for non-structural and structural construction materials

Aug 10, 2021
Juliana de Carvalho Izidoro, Denise Alves Fungaro, Luciana Cristina Viviani, Rogério da Costa Silva
Read Statistic: 729

Brine sludge (BS) is an industrial waste generated in large amounts by the Chlor-alkali industry and, usually disposed into industrial landfills. Because BS contains several chemical compounds, also presents a potential environmental impact. The feasibility of the utilization of brine sludge wastes for the preparation of value-added materials was investigated. The characterization of two brine sludge samples was performed in terms of chemical and physical composition, particle size distribution, X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and thermal analysis (DTA/TG). Elements like Ca, Si, Na, Mg, Al, Cl, and Fe were identified in the samples. The XRD results confirmed the crystalline nature of compounds and indicated that the main compounds in brine sludge samples were calcium carbonate, sodium chloride, magnesium hydroxide, and quartz. FTIR showed the presence of varying functional groups like carbonate, siloxane, and hydroxide. The two brine sludge samples can be considered as a fine powder with the mean diameter (d50) of 4.984 µm and 24.574 µm, for the BS from Santo André and Cubatão, respectively. The results indicated that the brine sludge samples presented favorable characteristics to use limestone ?ller and binder alternative to Portland cement in the nonstructural construction materials. The incorporation of brine sludge in geopolymeric materials is another possible use in sustainable construction material products. The production of value-added products from brine sludge will be an important contribution towards sustainable development adopted by the Chlor-alkali industry.

Synthesis and Characterization of Hydroxyapatite from Duck Eggshell by Wet Precipitation Process

Sep 17, 2021
Yelmida Azis, Cory Dian Alfarisi, Komalasari Komalasari, Khairat Khairat, Yusnimar Sahan
Read Statistic: 274

Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) is the most stable form of calcium phosphate and widely used in various medical applications, mainly in orthopedics and dentistry due to its close similarities with the inorganic mineral component of bone and teeth. This study aims to synthesize hydroxyapatite from duck eggshell using the precipitation method. The duck eggshell was calcined, hydrated (slaking) and underwent carbonation to form Precipitated Calcium Carbonate (PCC).  Afterwards, (NH4)2HPO4 was added to produce HAp by varying the molar ratio of Ca/P by 1.67, 1.77 and 1.87 and stirring speed by 200, 250, 300rpm under basic condition (pH 10 – 11). The best results were obtained at a molar ratio of 1.77 with 200rpm stirring speed. Furthermore, the X-ray Diffraction (XRD) analysis showed that its crystals were hexagonal with sizes of 23.062nm, in the absence of other crystalline phases. Therefore, the hydroxyapatite was obtained in the agglomerates form with a specific surface area of ??55.929m2/g.

3D Finite Element Model for Shear-dominant Failure of Reinforced Concrete Beams

Jan 28, 2022
Ridwan Rahman, Ilham Akbar, Rofriantona Rofriantona
Read Statistic: 170

This study explores the 3D FE modelling approach in determining the behaviour of shear-dominant responses of RC beams. Five RC beams (A1, A2, B1, C2 and C3) with different cross-sections, amount of tension reinforcement area, amount of shear reinforcement and the length of the span was analysed and the results were compared with the results of the experiment and 2D analysis available in published literature. RC beams analysed in this FE study were constructed as a discrete model using ABAQUS software. The concrete and the plate for loading as well as for supports were modelled using the C3D8R element while longitudinal steel bars and stirrups were modelled with the T3D2 element. The interaction between the steel bar and the concrete in the FE model was assumed perfectly bond. The material behaviour of concrete was modelled with the damage plasticity model where the yield or failure of the material was governed by the tensile cracking and the compressive crushing of the concrete by introducing the hardening variables. The results showed that crack propagation in the FE analysis matched the cracks observed in the test. The crack pattern on Beam A1, A2, B1 and C2 indicated that the specimens experienced flexure and shear failure while Beam C3 experienced less brittle behaviour. Estimates of strength and the load–deformation response of 3D analysis were certainly achieved with reasonable accuracy compared to that of 2D analysis. The difference of experiment-to-2D strength (Pu,exp - Pu,2D / Pu,exp) had a mean of 4.53 whereas the difference of experiment-to-3D strength (Pu,exp - Pu,3D / Pu,exp) had a mean of 1.83. Furthermore, the displacements at ultimate load gained in the 3D analysis were comparable to those of experiments. The difference of experiment-to-2D (du,exp - du,2D / du,exp) and experiment-to-3D (du,exp - du,3D / du,exp) midspan displacement had a mean of 19.91 and 10.89, respectively.

Simulations of the Crude Oil Tank Refurbishment Project Risks Using Monte Carlo

Feb 24, 2022
Ari Sandhyavitri, Arvin Arvin, Fajar Restuhadi
Read Statistic: 134

Simulation technology has assisted project stakeholders in predicting a range of the project results in the future under risks and uncertainties. The objectives of this article are to improve a comprehensive project planning in the perspective of the project scheduling by conducting simulations for the refurbishment of crude oil tank project risks using Monte Carlo simulations. The practical approaches for simulating the risks encompassed 3 stages: risk identification, assessment, and risk analysis using the Monte Carlo simulations. The implementation of Monte Carlo simulation in the form of stochastic approach however were not new, but the application of these approaches in the area of oil industrial projects was challenging. A Free Water Knock-Out (FWKO) tank project located in Duri, Indonesia was taken as a case study. The initial FWKO project duration was set up to be 180 working days, and it was delayed (up to 140% from the initial duration of the project planning). This study conducted deep questioner surveys from 25 oil industry stakeholders. It was identified 29 risk factors have been considered as the major causes of the project delay. The risk factors were then calculated qualitatively for performing risk indexes.  Based on the risk simulations (after 1000 iterations) using Monte Carlo simulations utilizing @risk application package (under uncertainties) there was found that the possibility of this project would  experience delays at the range of 47 days (126%) to 80 days (144%) from the initial project planning. This simulation had also identified the most sensitive activities causing project delays. The results was presented in the form of the spider graph diagram which assisted the project main stakeholders in developing a strategic decision during project planning phase.

A Review on Optimal Siting and Sizing of DSTATCOM

Feb 25, 2022
Dansarki Nanly Wesley, Abubakar Abdulkarim, P.U. Okorie, Adamu Halilu Jabire, Sani Saminu, Nasir Faruk, I.S. Madugu, A. U. Lawan, Iswadi Hasyim Rosma
Read Statistic: 92

The continuous demand for electrical energy by industries and domestic users have stressed the electricity consumption to a high level. Because most components of domestic and industrial systems are made of power electronics devices in their designs. In addition, modern electrical power distribution networks (DNs) are subjected to major disturbances. Consequently, today’s power system is laden with power quality problems such as excessive energy losses, voltage deviations, poor power factor (PF), voltage instability and reliability issues to mentioned just a few. To forestall these disturbances, Distribution Engineers have introduced the use of Custom Power Devices (CPDs) in order to reduce power losses so as improve power quality. Amongst CPDs, Distribution Static Compensator (D-STATCOM) proves most promising in minimizing power quality issues because it generates minimal harmonics, waste less power, has small size, high regulatory capability and cost effective. Researchers in recent years have focused on methodologies required for identifying the most suitable location and rating of D- STATCOM device based on divergent views. However, to date, only one author has so far reviewed a paper on this aspect of study. This paper discusses the latest study on appropriate installation and rating of D-STATCOM techniques for balanced and unbalanced radial distribution networks (UBRDNs). The paper has also provided a comprehensive literature study on the location of DSTATCOM in RDNs for power loss reduction and power quality enhancement. Comparative analyses of various techniques for development of DSTATCOM Objective functions and constraints; Merits and Demerits are presented.