bluuebunny/crossref_metadata_2025 huggingface dataset:
Utilization of Filter Feature Selection with Support Vector Machine for Tumours Classification
Authors: Tengku Mazlin T A H , Sallehuddin R , Zuriahati M Y
Published: August 2019

Due to rapid technology advancement, machine learning has been widely used for solving cancer classification problem. Classification performance is highly depending on the quality of input features. With an explosive increase number of features of high dimensional data, the occurrence of ambiguous samples and data redundancy directly leads to poor classification accuracy. Therefore, this paper presents a utilization of filter feature selection using four filter methods such as Information Gain, Gain Ratio, Chi-Squared and Relief-F by performing attribute rankings to remove the irrelevant and redundant features and evaluate the significance and correlation of input data. Then, the classification will be performed using Support Vector Machine (SVM) to measure the accuracy performance based on the number of selected features. The performance measurement will be validated on standard Breast Cancer datasets consisting of 286 instances obtained from the UCI repository. Evaluation metrics such as accuracy, sensitivity, specificity and Area under Receiver Operating Characteristic Curve (AUC) will be used to assess the performance of the SVM classifier using four different filter methods. Experimental result shows that Gain ratio improves the accuracy of SVM classification compared to Information Gain, Chi-Squared and Relief-F in classifying breast cancer data with only small number of features selected.
A Review of Common Features inComputational Thinking Frameworks in K-12 Education
Authors: Zahilah Mohamed Zaki Filzah , Wong Su Luan , Ridzwan Yaakub Mohd
Published: August 2019

Computational Thinking (CT) is not just another application of computer science principles in humans’ life. Computational Thinking has emerged as a systematic way of thinking, and problem-solving process. The awareness of inculcating CT into education, at different curricular level has started in various directions, and contexts. The article aimed to introduce the basic concepts of CT and highlight common key features within K-12 education frameworks, deployed by different bodies. Computational thinking is closely relatedto critical thinking, STEM (science, technology, engineering, and math) learning, as well as project-based learning. From the review, various computational thinking definitions and key features within education frameworks were identified, and this contributed in how computational thinking is being integrated in different context, respectively.
Improved Metaheuristic Algorithms for Metabolic Network Optimization
Authors: Mohd Daud K , Zakaria Z , Hassan R , Mohamad M S , Ali Shah Z
Published: August 2019

Metaheuristic algorithms have been used in various domains to solve the optimization problem. In metabolic engineering, the problem of identifying near-optimal reactions knockout that can optimize the production rate of desired metabolites are hindered by the complexity of the metabolic networks. Through Flux Balance Analysis, different metaheuristics algorithms have been improved to optimize the desired phenotypes. In this paper, a comparative study of four metaheuristic algorithms have been proposed. Differential Search Algorithm (DSA), Particle Swarm Optimization (PSO), Artificial Bee Colony (ABC) and Genetic Algorithm (GA) are considered. These algorithms are tested on succinic acid production in Escherichia coli. The comparative performances are measured based on production rate, growth rate, and computational time. Hence, from the results, the best metaheuristic algorithms to solve the metabolic network optimization is identified.
Electromagnetic control of fluid with magnetic particles in the stenosed region
Authors: Uddin Salah , Mohamad Mahathir , Kamardan Mghazali , Abd Hakim Mohamad Mahmod , Sufahani Suliadi , Rozaini Roslan
Published: August 2019

Hydrodynamic flow of Newtonian blood mixed with magnetic particles (red blood cells) through stenosed region is studied in this paper. The fluid is acted upon by an oscillating pressure gradient in a perpendicular magnetic field. Governing fractional momentum equations are analytically solved for axial velocities. Graphical analysis of velocity profiles against various physiological parameters is developed by coding in Mathematica. Effect of Caputo fractional operator α on axial velocities is also considered. Results show that blood and magnetic particles has increasing effect with maximum height of the stenosis and electric field, whereas, it has a decreasing effect with perpendicular magnetic field. Hence, the flow of blood can be controlled by applying sufficient and strong electric and magnetic field. This is an important fact in medical diagnosis and clinical treatment of various cardiovascular diseases, hypertension and atherosclerosis.
Exclusion Radius Particle Swarm Optimizer
Authors: Soo Chun Kit Alvin , Nuzly Abdull Hamed Haza , Adham Isa Mohd
Published: August 2019

Function optimization is a problem that has existed since modern engineering began. With multiple variables, brute-forcing or simple regression models become unfeasible. This paper proposes a shrinking population control method for a dynamic population particle swarm optimizer. The proposed control mechanism creates an exclusion zone, where particles are periodically purged from the simulation. The selection of particles purged relies on their particle best i.e. the position where it found its personal best fitness. Particles with their particle best outside of the exclusion zone with a predetermined radius from the current global best are removed from the simulation. The purging is done periodically in stages of equal iteration counts, and the radius is shrunk by a factor after every stage. By testing 5 benchmark mathematical functions, the results show that the proposed population control mechanism achieves better final optima than only a basic particle swarm optimizer and a simple shrinking dynamic population particle swarm optimizer where the worst performing particle is removed every so often.
Adoption of Machine Learning Techniques in Software Effort Estimation: An Overview
Authors: Hajar Arbain Siti , Azizah Ali Nor , Haszlinna Mustaffa Noorfa
Published: August 2019

Nowadays the significant trend of the effort estimation is in demand. It needs more data to be collected and the stakeholders require an effective and efficient software for processing, which makes the hardware and software cost development becomes steeply increasing. This scenario is true especially in the area of large industry, as the size of a software project is becoming more complex and bigger, the complexity of estimation is continuously increased. Effort estimation is part of the software engineering economic study on how to manage limited resources in a way a project could meet its target goal in a specified schedule, budget and scope. It is necessary to develop or adopt a useful software development process in executing a software development project by acting as a key constraint to the project. The accuracy of estimation is the main critical evaluation for every study. Recently, the machine learning techniques are becoming widely used in many effort estimation problems but there are limitations in some of the models and the variation research is still not enough. This paper presents an overview of the effort estimation using machine learning techniques and will be useful for researchers to provide future direction in the field of machine learning adoption in software effort estimation.
Optimum Placement of Piezo-Polymer Power Harvester for Epicardial Pacemaker
Authors: Bin Mohd. Asri Mohd. Hafizulhadi , Haikal Satria Muhammad , Talib Shukor , Samion Hasri
Published: August 2019

The major drawbacks of current pacemaker are the battery replacement. Patient will need additional surgery to replace the pacemaker unit with the new one. Utilization of rechargeable battery has been proposed to overcome this problem. However, recharging a battery within the body is not feasible due to tissue-heating and battery’s charge-and-discharge life-time. By those reasons, the utilization of piezo-polymer is suitable for a self-powered pacemaker as energy harvester. Piezo-polymer has been widely used as energy harvesting but none for cardiothoracic implantable device. This study focuses on specific implementation of piezo-polymer for epicardial pacemaker. The proposed fundamental research aims to identify the optimum location on the heart to put the piezo-polymer. This research will be conducted by simulation of left ventricle of heart via ANSYS. Heart stress-strain Finite Element Analysis (FEA) will be employed to obtain the maximum harvested power. The result shows the location of myocardial contraction that produces sufficient kinetic energy for the placement of the pacemaker. The heart 3-dimensional images are taken from cardiac-CT or cardiac-MRI to search the optimum location on the heart for energy harvesting and minimize pacing energy. In conclusion, the left ventricular wall motion and deformation caused by the cardiac wall movements have been analysed based on the left ventricle model in the simulation to get the location of the maximum kinetic energy formed.
Tensile Toughness Improvement of Poly(ethyleneco-vinyl acetate)(PEVA) by Incorporation of Hybrid Pre-dispersed O-MMT and Destabilized Bentonite
Authors: Fareyhynn Mohammed Fitri Tuty , Fazlina Osman Azlin , Othman Rahimah , Anwar Abdul Halim Khairul
Published: August 2019

Poly (ethylene-co-vinyl acetate) (PEVA) is a biocompatible copolymer, easily processed and designed for intricate biomedical products. However, its toughness; which is the combination of high flexibility and high strength is quite low to resist tearing during long term use in human biological system. In this study, the possibility to enhance the tensile toughness of the PEVA was studied. Several ratios of organically modified MMT and bentonite were used as hybrid nanofillers in the PEVA matrix to form hybrid nanocomposites. Both nanoclays were pre-dispersed and destabilized prior to melt compounding with the PEVA. Results indicated that the use of O-MMT and bentonite in a ratio of 4:1 brought the best increment in the tensile toughness of the PEVA. This could be related to the improved interactions between PEVA with the hybrid nanofillers.
Correlation of Microstructure and Flexural Strength of Fly Ash Geopolymer of Varying Molarities
Authors: Yong-Sing Ng , Yun-Ming Liew , Cheng-Yong Heah , Mustafa Al Bakri Abdullahi Mohd , Hui-Teng Ng , Naveed Amir
Published: August 2019

The present work studies and compares the flexural properties of fly ash geopolymer with varying molarity of sodium hydroxide (NaOH). Different molarities of NaOH solution (6M, 8M, 10M, 12M and 14M) are used to prepare the alkali activator (a mixture of NaOH and sodium silicate). The fly ash geopolymer were synthesised by using the solid/liquid ratio of 2.5 and sodium silicate/NaOH ratio of 2.5. The samples were cured at 60°C for 6 hours. The flexural test and microstructural analysis of fly ash geopolymer are performed after 28 days. Generally, the flexural strength of fly ash geopolymer increases when the molarity of NaOH increases. The 12M geopolymer has the highest flexural strength and a more densified microstructure is observed.
Mechanical Properties and Thermal Conductivity of Lightweight Foamed Geopolymer Concretes
Authors: Fatimah Azzahran Abdullah’ Siti , Yun-Ming Liew , Mustafa Al Bakri Abdullah Mohd , Cheng-Yong Heah , Zulkifly Khairunnisa
Published: August 2019

Foamed geopolymer concretes have a better performance in the thermal insulation properties compared to normal geopolymer concretes. In this research, lightweight aggregate geopolymer concretes was incorporated with different percentage of foaming agents (hydrogen peroxide). Compressive strength and thermal conductivity were measured. From results obtained, increased H2O2 contents will decrease the strength of lightweight foamed geopolymer concretes. Lightweight aggregate foamed geopolymer concretes (LWAFGC) with foaming agent content of 0.2wt.% obtained the highest strength of 19.601 MPa. Furthermore, Increased of H2O2 contents also will decrease the thermal conductivity of lightweight foamed geopolymer concretes. Lightweight foamed geopolymer concretes with 2wt.% H2O2 gave the good thermal insulating behavior when the thermal conductivity value recorded the lowest value compare to other wt.% of H2O2 content. The thermal conductivity value of lightweight foamed geopolymer concretes with 2wt.% of H2O2 was 0.072 W/m. K while, the thermal conductivity of other mixtures ranged between 0.077 W/m. K to 0.087 W/m. K., respectively.
Microstructural Analysis of Fly Ash-based Geopolymers with various Alkali Concentration
Authors: Hui-Teng Ng , Cheng-Yong Heah , Yun-Ming Liew , Mustafa Al Bakri Abdullah Mohd , Yong-Sing Ng
Published: August 2019

In the present work, a comparative study on the effect of different concentration of sodium hydroxide (NaOH) on fly ash-based geopolymer was investigated. The geopolymer synthesis by mixing fly ash with alkali activator (a mixture of NaOH and sodium silicate) at solid/liquid ratio of 2.5. The NaOH were used 6M, 8M, 10M, 12M and 14M with constant sodium silicate/NaOH ratio of 2.5. The geopolymers were cured at room temperature (29°C) for 24 hours and 60°C in oven for another 24 hours. The testing and analysis of the fly ash-based geopolymers were performed after 28 days. The adequate Na+ ions and densified microstructure were observed at optimum 8M-NaOH-activated fly ash-based geopolymers.
Fabrication of Novel Geopolymer Reinforced Tin Copper Solder in Suppressing Intermetallic Layer Growth
Authors: Nadiah ‘Izzati Binti Zulkifli Nur , Mustafa Al Bakri Abdullah Mohd , Arif Anuar Mohd Salleh Mohd
Published: August 2019

Currently, lead-free composite solder technology system is the new approach that have been considered as a promising replacement for toxic SnPb solder alloy. Sn-0.7Cu was used as matrix solder alloy while fly ash geopolymer and kaolin geopolymer with different compositions (0.5 wt.%, 1.0 wt.%, and 1.5 wt.%) was added as a reinforcement to increase the properties of solder alloy. The solder composite was prepared by using powder metallurgy method which consist of mixing, compaction, and sintering process via microwave oven. Microwave sintering approach results in more uniform heating, lower pore coarsening with cost-effective and energy efficiency. The chemical composition and morphology of geopolymer reinforcement was analysed by using X-ray Flourescene and Scanning Electron Microscope. The influences of the geopolymer particulates in the monolithic matrix solder on the interfacial intermetallic compound thickness and wettability were investigated by using optical microscope, while the specific value was measured by using J-image software. The melting point temperature were investigated by using differential scanning calorimeter (DSC). The influences of adding types of geopolymer particulates into Sn-0.7Cu lead free solder were investigated in terms of interfacial intermetallic compounds (IMCs) and thermal properties. It is noted that several addition of fly ash geopolymer and kaolin geopolymer particles can remarkably supressed the thickness of intermetallic layer between composite solder and the substrate and thus gives higher melting temperature but somehow certain composition resulted low in mechanical properties. Overall, the addition of 0.5 wt.% of kaolin geopolymer reinforcements into Sn-0.7Cu lead-free improved all the listed properties of the solder materials.
Investigation of Heat Released during Geopolymerization with Fly Ash based Geopolymer
Authors: Mohamed Rosnita , Abd Razak Rafiza , Mustafa Al Bakri Abdullah Mohd , Khimi Shuib Raa , Aida Mohd Mortar Nurul , Wazien Ahmad Zailani Warid
Published: August 2019

Geopolymerization consists of several chemical reactions that has been reported widely as an exothermic reaction. Previous studies on heat released during geopolymerization used metakaolin and fly ash of F class as a precursor for geopolymer. Meanwhile, in this study, fly ash of C class is used and a preliminary study has been conducted on determining the exothermic reaction of the geopolymerization with various ratios of solid-to-liquid ranging from 1.5 to 2.5. The amount of heat released was determined by using Differential Scanning Calorimeter. It was proven that different solid-to-liquid ratio affected the amount of heat released during geopolymerization as the highest amount of the heat released were recorded at the optimum solid-to-liquid ratio of 2.0.
Morphology Analysis of Spontaneous Tin (Sn) Whisker Growth on Lead-Free Solder
Authors: Noorliyana Hashim Aimi , Arif Anuar Mohd Salleh Mohd , Zaimah Mohd Mokhtar Noor
Published: August 2019

Due to the transition of the electronics industry to lead-free solders, the issue of tin (Sn) whisker has become one of the most imperative issues that need to be resolved. Moreover, with the increasing demand for electronics miniaturization, Sn whisker growth is a severe threat to the reliability of microelectronic devices. Sn whisker is a conductive tin structure that grows spontaneously from tin finished surfaces, which can lead to well-documented system failures in electronics industries. Assessment of the Sn whisker growth is difficult because of the slow and unpredictable nature of the Sn whisker formation. This paper presents the results of morphology analysis of Sn whisker growth in terms of Sn whiskers shape, average density and maximum length of Sn whisker on Sn-Cu solder finished using scanning electron microscope (SEM). Micro-indentation test was used to accelerate the growth of Sn whisker at room temperature storage.
Microstructure and Wettability of Graphene Oxide/TiO2 Thin Film Prepared via Sol-gel Method
Authors: Azani Azliza , Suriyani Che Halin Dewi , Abdul Razak Kamrosni , Mustafa Al Bakri Abdullah Mohd , Arif Anuar Mohd Salleh Mohd , Mahmed Norsuria , Mahyiddin Ramli Muhammad , Sepeai Suhaila
Published: August 2019

The microstructure of graphene oxide TiO2 (GO/TiO2) films on wettability and morphology properties were studied at different amount of Titanium isopropoxide with fixed amount of GO. GO/TiO2 thin films were prepared by using sol-gel method and deposited on glass substrate by spin-coating technique. The formation of GO/TiO2 was confirmed by using Fourier Transform Infrared Spectroscopy (FTIR) study while the morphology of GO/TiO2 was observed by Scanning Electron Microscopy (SEM) analysis. The hydrophilic/hydrophobic interactions of these films were examined by wettability test by measuring the water contact angle of the water drop on the surface of the coating. The wettability tests display that the contact angle of GO/TiO2 was increased from 90.0º to 118.7º after reduce the amount of titanium isopropoxide (TTIP). A small peaks of graphene and Ti were observed in the coated films and more pronounce peaks occur after the films were annealed. However, it was found that the annealing process does not improve the contact angle of the films as compared to the non-annealed films.
Assessment of Surface Ozone Concentration in Northern Peninsular Malaysia
Authors: Izzah Mohd Hashim Nur , Alia Izzati Mohd Yusoff Nur , Mohamed Noor Norazian , Zia Ul-Saufie Ahmad
Published: August 2019

This study investigate the surface ozone variations in northern Peninsular Malaysia which is Penang and Ipoh. A database with hourly air quality data and meteorological parameters covering the period of 2013 – 2016 obtained from Air Quality Division, the Department of Environment (DOE) were analysed. The association between the O3 concentration and meteorological parameter as well as the other air pollutants were identified by using Pearson Correlation Analysis and Principle Component Analysis. In order to predict the next three hour of O3 concentration, two models were developed which is MLR and PCAMLR. The results indicate that Ipoh has higher ozone concentration with maximum concentration of 0.124 ppm. The diurnal pattern of ozone displayed a peak during afternoon and low concentration during night-time until morning. On the other hand, the NO and NO2 concentration shows opposite pattern from ozone concentration. Maximum concentration of O3 reached the peak at late afternoon at approximately 2 p.m. in Penang and Ipoh while the lowest reading was recorded was at 8 a.m. A significant correlation was observed between O3 concentration with temperature and wind speed in both urban areas. MLR was chosen as best predictive and more accurate model in predicting O3 concentration during the peak hour compared to PCA-MLR.
Simulation-Based Optimization of Plastic Injection Molding Parameter for Aircraft Part Fabrication Using Response Surface Methodology (RSM)
Authors: Rosli M.U. , Ikman Ishak Muhammad , Riduan Jamalludin Mohd , Khor C.Y. , Nawi M.A.M. , Mohamad Syafiq A.K.
Published: August 2019

The small size and thin part characteristics of the honeycomb floor panel for the aircraft part product may cause problems in injection molding fabrication process. The objectives of this study is to find the most appropriate parameter in injection molding process for honeycomb floor panel by simulation using MoldFlow software and optimize the quality of injection molding process parameter by using Response Surface Methodology (RSM) as to obtain an optimal response and meets the requirement specification in the aviation scope. The crucial responses are shrinkage and warpage. Melt temperature, filling pressure and injection time are selected as the most influential factor for shrinkage and warpage. Model response was fitted by quadratic model. As the results, the optimum value suggested by the software were melt temperature of 360.02c, 60 MPa filling pressure and 4.70s injection time. With small differences error value between solution and simulation, 0.3% for shrinkage and 0.6% for warpage, the results was acceptable.
Optimization of Laminated Composites Characteristics via integration of Chamis Equation, Taguchi method and Principal Component Analysis
Authors: Syarafuddin Salam Syafiq , Mizamzul Mehat Nik , Kamaruddin Shahrul
Published: August 2019

To date, composite material has drawn significant attention due to its extended properties in various application. Many factors need to be considered in designing the composites which might leads to complex decision making. Therefore, this study focuses on analyzing and optimizing various factors including combination of material, volume fraction of fiber, ply angle, ply quantity, ply thickness and load applied via integration of the Taguchi method / Principal component analysis along with analytical analysis of Chamis equation. The finite element was adopted in conducting the analysis. Three responses were considered for the laminated composites namely displacement, stress and strain. The findings from the main effects analysis showed that the set of optimum parameters was identified as load applied of 2000N, ply thickness of 0.08 mm, ply quantity of 12 plies, ply angle of 0,90,0 °, material combination of boron/epoxy as well as volume fraction of 65%.
Synthesis of Metasilicate Gel from Rice Husk and Its Application as Medium of Growth Single Crystal Calcium Tartrate Tetrahydrate (CaC4H4O6.4H2O)
Authors: Eka Putri Suriati , Hasri  , Side Sumiati , Yunanda FR , Subaer
Published: August 2019

Has been done a research about synthesis metasilicate gel from rice husk and its application as medium of growth single crystal. synthesis This research was carried out in several stage namely sample preparation, metasilicate gel synthesis, crystal CaTT synthesis, and metasilicate gel characterization. Rice husk ash that used content SiO2 of 98.45 %, it was potential to be a sodium silicate filtrate. Filtrate of sodium silicate was reacted with tartrat acid (C4H6O6) and produce metasilicate gel with pH 5,00; 5,25; 5,50; 5,75 and 6,00. The supernatant of calcium chloride (CaCl2) diffuse into the gel and formed the clear white crystal CaTT as much as 0,2659 g at the optimum pH 5,25. Analysis of functional groups of metasilicate gel by FTIR provides the specific absorption of –OH group at 3400.05 cm-1 and 920.05 cm-1, C=O group at 1622.13 cm-1 and C-O group at 1346.31 cm-1, and the Si-O-Si group at 1064.71 cm-1. Characterization of gel metasilicate by XRD indicated that metasilicate gel produced formed on Na2C4H4O6.2H2O, compound of SiO2 and C-Grafit. Based on the analysis of functional groups by FTIR and characterization by XRD, it was concluded that the rice husk was potentially to be a sources of metasilicate gel as medium to grow single crystal of CaTT.
Fabrication of Zeolite-Geopolymer Hybrid Bulk Materials Based on Laterite Soils Deposit Gowa Regency, South Sulawesi, Indonesia
Authors: Dewi Permatasari Anita , Akifah Nur , Syamsih Amalia Nur , Rizal Fahlepy Muhammad , Sudarman Desa Susilo , Subaer
Published: August 2019

In this study, zeolite-geopolymer hybrid bulk materials were fabricated by using laterite soils deposit Gowa regency, South Sulawesi, Indonesia as a precursor for possible heavy metal absorbent. Laterite soils was calcined at 750°C for 6 hours to transform it into the amorphous aluminosilicate phase. Zeolite-geopolymer materials were produced through alkali activation method with curing temperature around 70°C for 2 hours. There were two different oxide molar ratios of SiO2/Al2O3 used to produce zeolite-geopolymer hybrid bulk materials and the specimens were designated as K1 and K2. The presence of zeolitic phase within geopolymer network was examined by using of XRD, FTIR, and SEM-EDS technique. The mechanical properties of the resulting material were studied by means of compressive and tensile strength. The results showed that Gowa laterite soil was succesfully fabricated as zeolite-geopolymer hybrid bulk materials, and the type of zeolite coined with geopolymers were zeolite A in sample K1 and un-named zeolite in sample K2. The mechanical strengths of zeolite-geopolymers produced in this study were below to those of pure geopolymers.
A preliminary study of thermal comfort and lighting in IHL library building
Authors: Hussin Norasikin , Abd Razak Azli , Baharum Faizal , Yaakob Y.
Published: August 2019

IHL (Institute of Higher Learning) library building is greatly utilized to access information from IT connection and materials. This building as a place to study, reading and writing for students and academics in the university. However, the indoor air quality and lighting system in the library building is not comfort and not satisfactory. In this paper, the investigation of thermal comfort and lighting in IHL library buildings. The library building of LBA, LBB and LBC has been selected. This study has been done with distribution of 350 set of questionnaires. The result shows that 63% of respondents claimed that uncomfortable with the environment because is very cold, which is indoor temperature in average of 20ºC. Meanwhile, 54.3% of respondents are unsatisfied with lighting level because it is too dimmed and most of them prefer to study near the window because of daylight. By lux meter reading, the illumination in average of 225 lux. From the reading, recommendations were made in order to enhance the thermal comfort and potential energy saving.
Removal of Nickel, Zinc and Copper from Plating Process Industrial Raw Effluent Via Hydroxide Precipitation Versus Sulphide Precipitation
Authors: Ain Zainuddin Nur , Azwan Raja Mamat Tengku , Imam Maarof Hawaiah , Wahidah Puasa Siti , Rohana Mohd Yatim Siti
Published: August 2019

Electroless plating wastewater contains mixed metals element. Although precipitation is the most common method applied to remove metals from the wastewater, it fails to completely precipitate all the metals at a single pH. The present work evaluates the effectiveness of the sulphide and the hydroxide precipitation for removal of nickel, zinc and copper from industrial wastewater, namely acid rinse and nickel rinse samples. The optimum pH and coagulant dosage were determined via Jar Test for both types of samples. Sulphide precipitation removed heavy metals more efficient than hydroxide precipitation. For the acid rinse sample, 95.32% of nickel was removed using sulphide precipitation while 76.66% removal using hydroxide precipitation. For nickel rinse sample, 93.75% of zinc was removed using sulphide while 68.8% removal using hydroxide. 65.75% of nickel was removed using both sulphide and hydroxide. Total removal of copper was achieved for both hydroxide and sulphide precipitation, either from acid rinse or nickel rinse samples.
Assessment of Ambient Air Pollution in Langkawi Island, Malaysia
Authors: Elis Sharmila Zulazmi Nur , Zia Ul-Saufie Ahmad , Nur Shaziayani Wan Mohd Rosly Wan , Mohamed Noor Norazian , Aida Zubir Nor
Published: August 2019

For many years, Southeast Asia region encountered several ongoing air pollution episodes. These episodes had indirectly significant impact on the air quality of neighboring countries. Hence, this study aims to assess the characteristics and trend of air pollution in Malaysia particularly at Langkawi Island. Air pollution hourly monitoring records from 2003 to 2017 were used in analyzing the statistical data analysis. Eight parameters were selected in this study which known as PM10, CO, SO2, NO2, O3, relative humidity (RH), temperature (T) and wind speed (WS). The results showed that the hourly trends of PM10, CO, SO2, NO2 and O3 in Langkawi Island were below the MAAQG standard. The results also indicated that dispersion of PM10 in Malaysia were significantly affected by temperature, wind speed and relative humidity.
Synthesis of dimercaptosuccinic acid (DMSA) coated magnetic nanoparticles: feasibility on dye decolorization and heavy metal adsorption
Authors: Syazwan Osman Mohamed , Asyiqin Noorossaidy Noorfarah , Azis Najwa , Syifa Salim Nur , Aqilah Zaini Nur , Alwani Ali Bashah Nur
Published: August 2019

As highlighted in UN sustainable development goals 2030 report, one of the important challenge in future is to provide clean water. Thus, enormous efforts have been made to improve water quality from recalcitrant pollutants such as organic dyes, heavy metal and others. Magnetic nanoparticles is one of viable candidate to degrade the above pollutants due to its unique properties such bifunctional (catalytic and adsorption) capability & ease for magnetic separation. However, one of the main challenge is to maintain its colloidal stability to exploit its advantages for water remediation. Thus, this work explored its colloidal stability by coating it with heavy metal chelating agent namely Dimercaptosuccinic Acid (DMSA). The resultant clustered magnetic nanoparticles were evaluated its feasibility by using Rhodamine B dye and lead (Pb) heavy metal as model system. It is revealed that DMSA-coated magnetic nanoparticles is a viable candidate for this model system.
Screening of factors influencing Pectin Extraction of Pomelo peels using 2-Level Factorial Design
Authors: Pagarra Halifah , Rahman Roshanida A. , Muis Abd. , Novia Arifin dan Arifah
Published: August 2019

A study was conducted to vary the parameters affecting the extraction of pectin from pomelo peels (Citrus maxima) using a 2-level factorial design (2LFD). Experimental design was carried out to screen for significant environmental factors for extraction results. The factors involved consisted of pH, temperature and extraction time. The results of the variance analysis (ANOVA) found three main factors that had a statistically significant effect on the results of pectin extraction, namely pH, temperature and extraction time. The following important factors are the interaction factors between pH and temperature, the interaction between temperature and extraction time, the interaction between pH and extraction time, the interaction between temperature and extraction time. Statistical analysis shows that the linear model is significant with R2 value of 0.9715. It was found that pH, temperature and extraction time are the most important parameters that affect the results of pomelo peels pectin extraction.
Study Photodegradation of Acid Orange 7 Using ZnO Waste Batteries
Authors: Hasri  , Sugiarti  , Sadriadi
Published: August 2019

This research aims to determine the ability of ZnO waste batteries to degrade Acid Orange 7. The first, synthesized zinc acetate precursors from Zn waste batteries. Next, synthesized ZnO from the precursor of zinc acetate and impregnated with zeolite to form a ZnO-Zeolite composite used the sol-gel method. Photodegradation test for Acid Orange 7 dye used a time 30, 60, 120, 240, 360 and 480 minute, concentration of 30, 50,75, 100, 150ppm with variations in pH 3, 5, 7, 9 and 11. Measurement of degradation resultsconcentration of Acid Orange 7 dye used a UV-Vis Spectrophotometer at a wavelength of 484.45 nm. The results showed that ZnO-Zeolite composites were able to degrade Acid Orange 7 dyes at pH 7, 480 minute, concentration 50 ppm with a degradation percentage of 94.15%.
Research Design and Identification of the Project Methodology Solutions Using the Finite Element Method
Authors: Bianca Pop Alina , Mihail Țîțu Aurel , Ioan Pop Gheorghe , Ceocea Costel , Țîțu Ștefan
Published: August 2019

The anticipation of the process variables (temperature, cutting forces, and stress distribution) plays an important role in the tool geometry design and cutting conditions optimization. The researchers found that the anticipation of these variables experimentally is costly both from a time requirement and financial point of view. Having this information, the finite element model becomes the most favourable alternative and most useful in all aspects. Existing Empirical models are very useful in demonstrating these matters, but if tests have not been carried out to create these models types, then it brings benefits in the improvement specifically to the process itself. This paper is focus to conduct the research and discover a methodical design solution based on the finite element method. This entails defining the input data used within the research framework, including: application type, finite element analysis, material model, and, of course, choosing the process parameters. After determining the input data, following the completion of the theoretical models of the experiment, respecting the finite element model, the output will take into account the final results of the selected research. In order to obtain optimal solutions and to increase the precision and accuracy of the obtained results, it is necessary to validate this using the experiment.
Characteristics of Wild Orchids in Mallawa Resort at Bantimurung Bulusaraung National Park, South Sulawesi, Indonesia
Authors: Fatmah Hiola Siti , Darma Dirawan Gufran , Wiharto Muhammad , Syamsiah
Published: August 2019

This study aims to determine the characteristics of wild orchids in the area of Resort Mallawa, Bantimurung Bulusaraung National Park. This type of research is descriptive with the exploration method, which is tracking the study area which is known to have a fairly high distribution of wild orchids. Exploration of wild orchids is carried out at 85 distribution points, with an altitude of 432 meters above sea level to 849 m above sea level. The results showed that there were 40 types of orchids, 33 species identified, and 7 species not identified. Based on the growth properties of wild orchids found were dominated by 35 species of epiphytic orchids, while for the type of growth was dominated by 24 species of sympodial orchids. The most found locations of wild orchids are in Mallenreng Hamlet I. The most common species is Trichoglottis geminata. Based on the height of the place, the species that grows at the highest position is Coelogyne sp., while in the lowest position is Dendrobium sp. 1. Based on the visual intensity of light, orchids were found in the shade as many as 5 species, half sheltered as many as 21 species, while in the open as many as 4 species. There are 5 orchid species that can grow in the shade and half shade, 3 species that grow in half shade and open places, and 2 species that can grow in three places. By knowing the presence and diversity of wild orchids in the study area shows that the ecosystem in the area is still quite good, considering that wild orchids are plants that are quite susceptible to interference.
Possibilities of ammonium ions fixation into mixed binders
Authors: Hajzler J , Novotny R , Opravil T , Ptacek P
Published: August 2019

The purpose of this study is to analyze the usability of ammonium ions fixation in mixed binders with the addition of high temperature fly ash. The experiment used high-temperature fly ash from operations in which the secondary flue gas denitrification methods have been implemented, specifically by the method of the selective non-catalytic reduction, known as DeNOx. The fixation of ammonium ions was performed by the addition of sodium hexanitrocobaltate(III). The study examines the influence of addition of cobalt(III) complex compound on the release of ammonia into the environment during the mixing the mixed binder. The released ammonia was quantitatively captured into the acid and subsequently titrated. The effect of cobalt(III) complex compound on the rate of hydration and mechanical properties of the mixed binders was also studied. The influence on the environment in terms of leachability was observed.
The effect of burnt lime addition on hydration of Ultra-high performance cementitious composites
Authors: Novotný R , Bartoníčková E , Kotrla J
Published: August 2019

The paper deals with the burnt lime utilization as a source of calcium ions participated during hydration process of ultra-high performance cementitious composites. These type of ultra-high performance cementitious composites are based on the high content of silica fume that together with calcium ions form the binder phase. In the case of ordinary Portland cement, the hydration during induction period supposed to be too slow for dissolution of required amount of calcium ions necessary for the pozzolanic reaction of presented silica fume. The low addition of the lime should be a sufficient calcium source that allow the starting of the pozzolanic reaction before the acceleration period occurs. The calcium ions content from the beginning of the reaction was controlled by an addition of soft-burnt and dead-burnt lime. Its influence was studied in terms of hydration process by isothermal calorimetry. Based on the experimental data, the hydration reaction mechanism was proposed.
Preparation and properties of Portland limestone cements
Authors: Stanek T , Bohac M , Rybova A , Zezulova A
Published: August 2019

Limestone is a suitable substitute for economically less favourable Portland clinker in Portland blended cements. Limestone in cement not only serves as a very fine filler, but can also act as a reaction component. In this work, the properties of laboratory Portland cements with limestone were studied. The cements were prepared from two limestone types and two clinker types with a graded limestone content of up to 30 wt. %. The limestones had a different CaCO3 content. Clinkers were distinguished by a marked difference in C3A content and hydraulic activity. The effect of limestones on the technological properties of cements, the hydration process and the impact of separate and together grinding of limestone and clinker were studied. In this case, the type of clinker had stronger impact than the type of limestone on the technological parameters. It was also confirmed that a low limestone content has a positive effect on cement hydration.
The effect of zinc, water to binder ratio and silica fume on the hydration and mechanical properties of Portland cement mixtures
Authors: Siler P , Kolarova I , Bednarek J , Janca M , Masilko J , Novotny R , Opravil T
Published: August 2019

The amount of zinc in the clinker or in the secondary raw materials has been increasing in recent years mainly due to the processing of waste materials containing zinc. The aim of this work is to show the effect of zinc on hydration of Portland cement and mechanical properties. These effects were studied by isoperibol calorimetry and mechanical properties testing. Zinc was added to the cement in the form poorly soluble compound ZnO. The concentration of zinc added was chosen as 1wt. percent. The newly formed compounds during hydration were identified by X-ray diffraction method (XRD). Another objective is to show the effect of silica fume (microsilica, SF) as the secondary raw material and water to binder ratio on hydration of cement in the presence of zinc.
Rheological study on influence of hydroxypropyl derivatives of guar gum, cellulose, and chitosan on the properties of natural hydraulic lime pastes
Authors: Zizlavsky T , Vysvaril M , Rovnanikova P
Published: August 2019

Viscosity enhancing admixtures are widely used to improve properties of concrete and ready-mix mortars. Guar gum derivatives and chitosan ethers are reported to have water-retaining effect, which is beneficial for the adhesion of the mixture as well as for the hydratation of hydraulic particles in the binder phase of concrete or natural hydraulic lime (NHL) mortars. Influence of addition of admixtures in doses of 1, 5, and 10‰ of the binder weight has been studied on NHL based pastes with constant water:binder ratio. The measurements were carried out on the Discovery HR-1 rheometer with DIN concentric cylinders geometry. The flow properties and viscoelastic properties were studied on the specified mixtures. Pastes expressed shear-thinning behaviour with thixotropic character of flow curves. Admixture addition caused increase of yield stress, fluidity index and consistency coefficient varying on the amount and type of the admixture. Differences in the effectivity of admixtures were observed, the dosage-dependency of the admixtures varied.
Influence of soil-cement composition on its deformability
Authors: Tracz T , Brasse K , Zdeb T , Bielecka J
Published: August 2019

The paper discusses the results of deformability tests of soil-cement composites made with cohesive and non-cohesive soils. The compositions of the materials analysed were diversified in terms of their cement paste volume fractions and water-cement ratios. The aim of the research was to determine the secant modulus of elasticity in uniaxial compression of soil-cement composites in accordance with the EN 12390-13 standard dedicated to concrete testing. Due to the lower level of strength of the materials in question in comparison with ordinary concrete, nominal stress was lowered and the loading and unloading rates were modified. The number of loading cycles required for the determination of stabilised deformations was verified. The test results obtained and their analysis indicate the significant impact of the type of soil on the deformability of soil-cement composites. It was also found that the deformability of the materials tested is sensitive to changes in their compositions.
Packing density modelling of non-spherical aggreg ates for particle composite design
Authors: Koutny O , Kratochvil J , Drdlova M , Bystrianska E
Published: August 2019

The presented study follows the author’s results of research where 3-parameter packing model for packing density determination was derived and calibrated for multimodal particular system. In this study previously derived model is extended by fourth parameter related to particle shape and its effect on bulk packing density. The model is primary derived for high performance cementitious composite design where compact structure and low binder content is preferred to maximise mechanical properties and durability. The effect of aggregate packing density on mechanical properties of ultra-high performance cementitious composites is investigated, using derived packing model
Effect of curing environment on length changes of alkali-activated slag/cement kiln by-pass dust mixtures
Authors: Bilek V , Kalina L , Simonova H
Published: August 2019

This paper investigates the combination of commonly used blast furnace slag (BFS) and quite non-traditional cement kiln by-pass dust (BD) for the preparation of alkali-activated binder. More specifically, the possibilities of alkali-activated slag (AAS) shrinkage compensation and cracking mitigation using BD were studied. For this purpose, mixtures with ratios of BFS/BD ranging from 100/0 to 60/40 were prepared and cured in different environment, namely autogenous conditions, water curing, air curing and their combinations. The results showed that curing regime is a determinative parameter for performance of the mixtures: BD containing specimens showed a certain expansion during the first days of water curing leading to AAS shrinkage compensation, while in absence of water curing increasing dose of BD increased drying shrinkage significantly.
Development of acoustic insulating materials from recycled textile fiber
Authors: Zach J , Bubenik J , Novak V , Trisko P
Published: August 2019

Nowadays, there is an increasing demand for recycling materials and hence for greater environmental friendliness. The issue of waste management and recycling is a very actual topic in the society of most developed countries. One area where the vast amount of waste is generated every year is the textile industry. Textile waste (old clothing, fashion accessories, car upholstery, home textiles and other textile products) is most often made up of a combination of different types of natural fibers (cotton, silk) and man-made fibers (polyester, viscose). Thanks to the large amount of this waste and recycling technologies available, the secondary textile fibers are an interesting secondary raw material that can be used for the production of thermal and acoustic insulators. The article describes research results in the development of medium and heavy insulating mats usable in vertical constructions and floating floor structures.
Substitution of aeration additive with recycled rubber and its effect on compressive strength and modulus of elasticity
Authors: Chylik R , Trtik T , Fladr J , Seps K
Published: August 2019

The article follows on previous research by authors dealing with the properties of concrete with the addition of recycled rubber. This paper describes the substitution of aeration additives with rubber recycled material and the effect of this substitution on strength and modulus of elasticity. For concrete mixes containing 40 kg/m3 of recycled rubber, the air content of the fresh concrete was measured. Concrete with the same amount of fresh air was made using an aeration additive. Compressive strength and modulus of elasticity were compared.
Proposal of methodology for testing resistance of building materials against mold infestation
Authors: Kukletova I , Chromkova I
Published: August 2019

Molds attack buildings on a broad scale, cause significant damage and carry a number of negative effects on human health. The design of the methodology is based on EN 60068-2-10 “Environmental Impact Testing – Parts 2-10: Tests – Test J and Instructions: Mold Growth” and ČSN 72 4310 “Testing the Resistance of Building Products and Materials against Mold”. However, the first of these standards is intended for electrical industry and the other was published in 1975 with no later revisions. The design of the new methodology aims at simplifying and updating and, last but not least, imitating the success of already implemented methodology for testing resistance to green algae growth. The proposed methodology was successfully verified on both standards and real samples.