The performance of modified jatropha-based nanofluid during turning process

The industry's extensive use of petroleum-based metalworking fluid (MWF) harms the environment and humans. The production of bio-based MWF, especially from crude jatropha oil (CJO), has therefore taken numerous initiatives. This aimed to formulate newly modified jatropha oil (MJO) with the addition of 0.05wt.% hBN and 0.05wt.% MoS2 as the nanofluid for MWF. The performance of the nanofluids was determined through the turning process in terms of cutting temperature, workpiece surface roughness, tool life and tool wear of the tool lubricated by the nanofluids. The performance of the nanofluid samples was compared with the synthetic ester (SE). From the results, after conducted 100mm axial cutting length MJO+hBN+MoS2 recorded the lowest in cutting temperature and surface roughness compared to all samples. The result shows that MJO+hBN+MoS2 has longer tool life (6500mm) compared to SE (6000mm). Abrasion and adhesion were observed as the dominant tool wear mechanism. In conclusion, MJO+hBN+MoS2 shows better machining performance and has the potential to be an environmentally friendly metalworking fluid

Linear-nonlinear stiffness responses of carbon fiber-reinforced polymer composite materials and structures: a numerical study

The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures

Polyethersulfone/HFO mixed matrix membrane for enhanced oily wastewater rejection

The recent growth of oil and gas industry has led to the increase of oily wastewater release. Membrane technology has been in the spotlight in recent advancement to treat the oily wastewater. Fouling due to surfactant adsorption and/or oil droplets plugging the pore has become one of the major hindrances in most of the research on oily wastewater treatment. In this work, self-synthesized hydrous ferric dioxide nanoparticles (HFO NPs) via chemical precipitation method were incorporated in polyethersulfone (PES) to fabricate a novel nanocomposite mixed matrix membranes (MMMs) for ultrafiltration (UF). The morphologies and physicochemical properties of prepared HFO NPs and MMMs were characterized using Scanning Electron Microscopy (SEM) and Transmission electron microscope (TEM), contact angle goniometer, before further subjected to water permeation test and oil rejection test. It was found that contact angle of membrane decreased remarkably with an increase in HFO nanoparticle loading from 70° to 38° at which proved its improved hydrophilicity which led to a significant rise in permeate flux, achieving 168.06 L/m2h bar in comparison to 63.67 L/m2h bar shown by the plain PES membrane. Total rejection of oil (100% rejection) demonstrated by the MMMs has confirmed the superior potential of PES/HFO UF membrane for total purification of oily wastewater especially to be reused in oilfield and refinery processes as well as to be released to the environment

Analisis Break Even Point sebagai Dasar Pengambilan Keputusan Penetapan Harga Jual pada USAha Kecil dan Menengah (UKM) di Kota Banda Aceh

The purpose of this research is to analyse the break even point on selling price determination, to know the difference of selling price between the one which is stated by SMEs in trading sector in Banda Aceh and the one which is the result of break even point analysis, and also to know the correlation between the break even point and selling price. Type of this research is statistical descriptive analysis. Population in this research are SMEs listed in Dinas Perindustrian, Perdagangan, Koperasi, dan UKM in Banda Aceh. Based on certain criterias, there are 30 SMEs as the samples of the research. This research shows that there is a difference betweet the rate of selling price determined by the SMEs and break even point analysis result. Based on correlation test, there is positive significant correlation between selling price and break even point

Tarekat Naqshabandiyyah Khalidiyyah in Malaysia: a Study on the Leadership of Haji Ishaq Bin Muhammad Arif

: The Tarekat Naqshabandiyyah Khalidiyyah lead by Haji Ishaq has many followers and is also known especially among other tarekat followers in Malaysia. This article is navigating through the leadership of Haji Ishaq Bin Muhammad Arif, the emergence of tarekat Naqshabandiyyah Khalidiyyah he lead and its evolution in Malaysia. Beside the data collected through the manuscript written by Haji Ishaq, his murids works were also studied. Field observations were also performed at several sites that are identified to be the centers of the movement. Also, some senior students of Haji Ishaq were interviewed to strengthen the arguments of the manuscript data. This study had discovered that tarekat Naqshabandiyyah Khalidiyyah lead by Haji Ishaq was large group with many followers, made up of diverse backgrounds, including academicians and professionals. The power of this group is reflected in the extensive network of centers that are located in several states in Malaysia

Pemanfaatan Limbah Jagung sebagai Substrat dalam Menghasilkan Poli-Β-Hidroksi Butirat (Phb) oleh Isolat Bakteri Asal Pabrik Gula Arasoe Bone

The research about Waste of Corn as Substrate In Produce Poly-β-Hydroxy Butyrate (PHB) by Bacterial Isolates Origin Sugar Factory Arasoe Bone. The research purpose to determine the ability of bacterial isolates from sugar mills Arasoe Bone is BA9 and MA4 and nitrogen concentration optimal for producing the PHB. With usewaste of corn as a source of carbon with a concentration 1%, 2%, 3% and as control positive glucose 1%, as well as use of ammonium sulfate as nitrogen source at a concentration of 0.05%, 0.1% and 0.15%. Total Analysis of PHB done with use UV-VIS spectrophotometer and a wavelength of 235 nm and using analysis a regression equation. The result of this study that use of corn as a source of carbon waste can produce PHB either by BA9 and MA4 isolates though still lower than glucose as the carbon source. The concentration of nitrogen source (ammonium sulfate), which accumulate PHB optimal concentration of ammonium sulfate that is at 0.1%

Kinetic modeling of LDPE pyrolysis using coats-Redfern method

Pyrolysis of polymer waste can potentially be a source of renewable energy, as it is a possible way to produce liquid fuel. In order to industrialize the process, the kinetic behavior of the pyrolysis has to be well understood. In this study, pyrolysis of virgin low density polyethylene (LDPE) was studied using thermogravimetric analysis (TGA). The test was carried out from 303-923 K at 20K/min in a nitrogen atmosphere. The TGA result was used to develop suitable models to calculate the activation energy, E, and pre-exponential factor, A, using Coats-Redfern method. Proximate and elemental analysis was also carried out on the LDPE sample. It was discovered that all reaction models were able to produce satisfactory linear fit of the data, with high correlation coefficients. Therefore, Coats-Redfern method cannot be used alone, but must be coupled with other methods to determine the correct reaction mechanism for the pyrolysis. By assuming first-order reaction, the calculated activation energy and pre-exponential factor are 166.75 kJ/mol and 4.97 x 1011 s-1, respectively

Metacognitive skills of Malaysian students in non-routine mathematical problem solving

Metacognitive skills play an important role in solving mathematical problems. However, there is a lack of empirical studies on the role of metacognitive skills in solving mathematical problems, particularly non-routine ones. Therefore, this study was undertaken to identify students' metacognitive skills and the impact of such skills on non-routine mathematical problem solving. By using a quantitative method, a total of 304 students in Johor Bahru district were involved in the study. A Self-Monitoring Questionnaire (SMQ) and a mathematical test were used in data collection. Data were analysed using descriptive and inferential statistics such as frequency, percentage, mean, the Mann-Whitney U test, and the Kruskal-Wallis H test. Results showed that the level of the students' performance in solving non-routine mathematical problems was very low. There was also a significant difference in the metacognitive skills among students with different performance levels in solving non-routine mathematical problems, and we concluded that these metacognitive skills should be emphasised in this process

Pengaruh Karakteristik Merek, Diferensiasi Produk, Kepercayaan Merek Terhadap Loyalitas Merek Telepon Seluler Blackberry

Trust in brand became the basis of the creation of the customer\u27s brand loyalty considering problems brand to be one of the issues that should be monitored constantly by each company. Increasingly fierce competition and growing customer expectations Blackberry encourage companies to focus more on efforts to retain existing customers, through increased consumer loyalty to the brand. The increase in consumer brand loyalty is influenced by many factors, including brand characteristics, product differentiation and brand trust. The problem in this study was a decrease in the number of BlackBerry users in 2010 amid rise in the number of users in each year over the last 6 years. This study aims to determine whether there is influence between brand characteristics, product differentiation and brand trust on brand loyalty.This research used explanatory research. From 221 research population taked 69 respondents as sample with Simple Random Sampling method. Collecting data used questionnaire. Analysis data used correlation coefficient, determination coefficient, regression analysis, t test, and F test.The Result this research show that brand characteristic, product differentiation and brand trust have positive influence and significant on brand loyalty (with result as bis as 26,9%, 44,9%, and 33,2% for each variable) as well as in simultaneous as big as 52,1% with product differentiation gave biggest influence.For to the Blackberry should still perform periodic evaluations and improvements that can be better compared with other products, and has its own character, must maintain a viable product differentiation for consumers that is based on the quality and features are given, as well as providing design and warranty in accordance with the product the. For further research needs to be conducted research on factors other than the characteristics of the brand, product differentiation and brand trust on brand loyalty as price, equity, consumer satisfaction

Self-efficacy of catering students of Faculty Technical and Vocational Education, University Tun Hussein Onn Malaysia in the Field of Career to be pursued

The increasing rate of unemployed graduates in Malaysia has received alarming attention in recents years. One of the factors that contribute to the unemployment problem is the lack of self-efficacy among graduates in making career choices. Therefore, this study was conducted to identify the self-efficacy of catering students to make decision on career field options to be pursued either as a teacher, hospitality employee or entrepreneur. The design of this study is a quantitative descriptive study through survey and questionnaire is used as research instruments. A total of 66 catering students of year 3 and 4 from Faculty of Technical and Vocational Education (FPTV) were selected as the study sample. The data obtained were analyzed using Statistical Package for Social Science (SPSS) version 22.00 software involving mean, standard deviation, and ANOVA. The results showed that the mean scores of self-efficacy of catering students were high to become teachers (M= 4.11, SD=0.617) and followed by hospitality employee (M= 3.87, SD= 0.574) and entrepreneurs (M= 3.93, SD=0.514). However, there was no significant difference between the three career fields with a value of p = 0.052. In conclusion, catering students have high self-efficacy in venturing into the field of career when graduating from university. Graduates need to see the importance of enhancing self-efficacy because it opens paths for career opportunities and advancement