Journal of Science and Technology https://publisher.uthm.edu.my/ojs/index.php/JST <p class="MsoNormal" style="text-align: justify;">The Journal of Science and Technology (JST) is a peer reviewed journal that publishes twice a year&nbsp; (June and December) on articles concerning&nbsp;all areas of science and technology in both theoretical and applied research. JST welcome article submissions from all science and technology research areas including Physics, Chemistry, Biology, Mathematics, Statistics, Biodiversity, Food Science Technology, Engineering Science and Educational Science. JST is intended to provide a forum for the expression of new ideas, as well as a place for exposition of these areas of knowledge&nbsp;that can further understanding of science and technology issues and concerns.</p> Universiti Tun Hussein Onn Malaysia en-US Journal of Science and Technology 2229-8460 <p><strong>Open access licenses</strong></p> <p>Open Access is by licensing the content with a&nbsp;<a href="http://creativecommons.org/choose/">Creative Commons (CC) license</a>.&nbsp;</p> <p><a href="https://creativecommons.org/licenses/by-nc-sa/4.0/" rel="license"><img src="https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png" alt="Creative Commons License"></a><br>This work is licensed under a&nbsp;<a href="https://creativecommons.org/licenses/by-nc-sa/4.0/" rel="license">Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License</a>.</p> <p>&nbsp;</p> Researches of Yield and Quality Characteristics of Lavandin (Lavandula X İntermedia Emeric Ex Loisel) Under Continental Type of Climate https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/4962 <p>This study was carried out in Lavandin (Lavandula x intermedia Emeric ex Loisel) planted in the farmers' land in Kayseri, Turkey in 2015-2017. Kayseri is a region with a continental climate in Turkey's Central Anatolia Region. In this study, dry flower weight, essential oil content, essential oil yield, and essential oil components were investigated in demonstrations established in 14 locations in Kayseri. Accordingly, in Lavandin, with dry flower weight of 30-127 kg ha<sup>-1</sup>, the essential oil content was 2.72-9.00% and the essential oil yield was found between 17-77 lt ha<sup>-1</sup>. A total of 37 components were identified in the essential oil analysis including linalool (37.59-50.48%), linalyl acetate (1.10-40.23%), 1.8 cineole (2.09-17.72%), and camphor (4.13-9.21%). In Lavandin (Lavandula x intermedia Emeric ex Loisel) cultivation studies in the Kayseri, altitude below 1350-1400 m positive results were obtained in the region.</p> Ahmet YENİKALAYCI Kemal Gul Mahmut Gunes Copyright (c) 2019 Journal of Science and Technology 2019-12-30 2019-12-30 11 2 1 7 Inhibitive Effect of Glutaraldehyde on the Corrosion of Aluminum in Hydrochloric Acid Solution https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/4408 <p>The inhibition effect of glutaraldehyde on the corrosion of aluminum in 1.4 M HCl solution at 308-318 K was investigated by using weight loss method and characterized by Fourier Transform Infrared Spectroscopy (FTIR) &amp; Scanning Electron Microscopic Analysis (SEM). The results show that the inhibition efficiency increases with increasing inhibitor concentration and decreases with rising temperature. The activation energy value was 20.48 kJ mol<sup>-1</sup> for the uninhibited acid solution which increased to 33.79 kJ mol<sup>-1</sup> in the presence of 0.1 M inhibitor concentration. Langmuir adsorption isotherm was found to provide an accurate description of the adsorption behavior of the investigated inhibitor. The thermodynamic parameters such as adsorption equilibrium constant (K<sub>ads</sub>), free energy of adsorption (ΔG<sub>ads</sub>), heat of adsorption (ΔH<sub>ads</sub>) and entropy of adsorption (ΔS<sub>ads</sub>) have been calculated and discussed in detail.</p> Musa Husaini Bishir Usman Muhammad Bashir Ibrahim Copyright (c) 2019 Journal of Science and Technology 2019-12-30 2019-12-30 11 2 8 16 Using Historical Return Data in the Black-Litterman Model for Optimal Portfolio Decision https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/3965 <p>In this paper, the Black-Litterman model which is the improved mean-variance optimization model, is discussed. Basically, the views given by the investors were incorporated into this model so that their views on risk and return, and risk tolerance could be quantified. For doing so, the market rates of return for the assets were calculated from the geometric mean. Moreover, the views of the investors were expressed in the matrix form. Then, the covariance matrix and the diagonal covariance matrix of the assets return were calculated. Accordingly, the mean rate of the asset return was computed. On this basis, the Black-Litterman optimization model was constructed. This model formulation was done by taking a set of possible rates of return for the assets. Particularly, the corresponding optimal portfolios of the assets with lower risk and higher expected return were further determined. For illustration, the historical return data for S&amp;P 500, 3-month Treasury bill, and 10-year Treasury bond from 1928 to 2016 were employed to demonstrate the formulation of the ideal investment portfolio model. As a result, the efficient frontier of the portfolio is shown and the discussion is made. In conclusion, the Black-Litterman model could provide the optimal investment decision practically.</p> Stephanie See Weng Su Sie Long Kek Mohd Asrul Affendi Abdullah Copyright (c) 2019 Journal of Science and Technology 2019-12-30 2019-12-30 11 2 17 25 Statistical Clustering Performance in Pavement Condition Prediction as Decision Supporting System Tool https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/4737 <p>Mathematical methods and statistical patterns have always been considered by managers, designers and science and technology expert in order to develop technology and engineering objectives. During the development of data-gathering tools and increment of data-bases, data mining have made suitable tools in management and engineering. The assessment of roads' maintenance is highly important in order to prevent early deterioration of roads and performing maximum road capacity during the service-life. Pavement management of roads has also implemented this tool to make proper decisions and preferences of pavement repair methods, using decision tree. Through engineering management, cluster analysis is one of the basic tools of data mining and knowledge discovery and makes the decision making, easier in engineering. Data categorization is helpful for planning and is important in picking proper methods. This study was performed by using recorded data from other scientific sources considering data mining method and analyzing data with respect to statistical clustering. The results indicate that bitumen content in asphalt mix, pavement age, marshal strength and rate of passing vehicles have the most important effect on decrement of condition index of pavement, relatively. Also, the highest deterioration in asphalt happens in 5.5% and higher values of bitumen content and the progressive deteriorations take place when the pavement age exceeds 35 years.</p> Mohammad Mehdi Khabiri Copyright (c) 2019 Journal of Science and Technology 2019-12-30 2019-12-30 11 2 26 35 An Approximate Performance of Self-Similar Lognormal M 1 K Internet Traffic Model https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/5049 <p>Modeling Internet traffic data with the inherent condition of concurrent arrival of packets requires the use of heavy-tailed distributions. In this paper, we present log-normal distribution as a suitable heavy-tailed distribution for modeling self-similar Internet arrival process. Specifically, we developed its approximate performance measures for large buffer size. Results using the simulated data confirm the adequacy of the proposed model.</p> Jumoke Popoola Olusogo Popoola Oyebayo Ridwan Olaniran Copyright (c) 2019 Journal of Science and Technology 2019-12-30 2019-12-30 11 2 36 42