http://dspace.zu.edu.ly/xmlui/handle/1/1159 Wed, 08 Apr 2026 21:44:42 GMT 2026-04-08T21:44:42Z http://dspace.zu.edu.ly/xmlui/handle/1/1725 غلاف+محتويات العدد 23 المجلد الرابع cover+issue content, غلاف+محتويات Fri, 31 Dec 2021 00:00:00 GMT http://dspace.zu.edu.ly/xmlui/handle/1/1725 2021-12-31T00:00:00Z http://dspace.zu.edu.ly/xmlui/handle/1/1724 The Optizmum Condition for Lactic Acid Yield From Pineapple Wastewater Using Lactobacillus Casei Hassan, Saber Salem For several reasons, the utilization of the fermentation process to produce lactic acid has been studied from carbohydrate sources and other sources. Accordingly, the use of biotechnology to produce lactic acid is found to be less costly compared to chemical synthesis. Lactic acid, which is the raw material for the production of biodegradable poly lactic acid, can easily be obtained from industrial wastes such as pineapple waste. The process can positively affect the environment by reducing the amount of liquid and solid waste that is harmful to the environment. This study aims to optimize the conditions for the lactic acid yield from pineapple wastewater using lactobacillus casei. The lactobacillus casei was propagated in MRS broth for three successive times before the fermentation of pineapple wastewater as the substrate, using the cheapest and simplest technique, namely shake flask fermentation in aerobic conditions at different temperatures (30°C, 37°C, 45°C), different inoculum sizes (5%, 10%, 15%) and pH. The viability of probiotics was determined spectrophotometrically at a 600nm wavelength. The results showed that the best bacterial growth to produce an optimum lactic acid concentration was obtained at 37°C and a 5% inoculum size at pH 6. The effect of the pineapple wastewater culture medium on bacterial growth was comparable to that of MRS. Fri, 31 Dec 2021 00:00:00 GMT http://dspace.zu.edu.ly/xmlui/handle/1/1724 2021-12-31T00:00:00Z http://dspace.zu.edu.ly/xmlui/handle/1/1723 Experimentally Determination of Burst Pressure and Failure Location of Liquefied Petroleum Gas Cylinder Fadel, Abdulnaser Hamza; Yahya, Najeeb A. Liquefied Petroleum Gas (LPG) cylinder is a thin pressure vessel used to meet energy requirements in household applications. Bursting of a pressure vessel is disastrous and many fatal accidents are happened due to pressure vessel bursting. The main goal of the current paper is focused to determine experimentally the burst pressures (BP) and failure locations of LPG cylinders. To ensure that the cylinders are in conformance with International Standards. The experiments were carried out on two samples of LPG cylinders used in Libya (C1 and C2). The experimental burst test investigations done by hydrostatic test in which the cylinders were internally pressurized with water. The permanent volume expansions of the LPG cylinders due to internal pressure were also examined. All tests in this study were subject to standard specifications (ISO 4706), which is needed to be conducted on LPG cylinders before introducing them to the Libyan market. Among these tests, the hydro-tests are major tests to be conducted on LPG Cylinders to get approval and acceptance. Hydro-tests on LPG cylinders reveal permanent volumetric expansion of the cylinder, nominal hoop stresses at the time of destruction and the internal pressure at which a cylinder burst. These values are important to ensure that the design and construction of cylinders are safe and compiled to standards. Fri, 31 Dec 2021 00:00:00 GMT http://dspace.zu.edu.ly/xmlui/handle/1/1723 2021-12-31T00:00:00Z http://dspace.zu.edu.ly/xmlui/handle/1/1722 Darcy Flow and Heat Transfer Through Porous Media Inside a Horizontal Fixed Packed Bed Ahmed, Alhassen A.; Gennish, Ramadan; Bilrrazig, Amhimmid; Jolgam, Shaban A. The present work is focused on the simulation of forced convection airflow through a horizontal fixed packed bed. The flow was considered at low Reynolds numbers (0.01 to 5), where the problem was governed by the Darcy model and the solution performed by COMSOL Multiphysics 05. The analysis was carried out under the assumptions of steady, incompressible, Newtonian, constant fluid properties. For the thermal conditions, a uniform wall heat flux at the wall boundary is taken to be constant as q = 150 W/m² while the porosity of the bed is set to be as ԑ = 0.39. The results showed that the temperature is greatly affected by the Reynolds number. As the Reynolds number increases the Nusselt number and convective heat transfer coefficient increase consequently the temperature decreases through all the bed, also the pressure drop through the bed increases as the Reynolds number increases and vice versa. Fri, 31 Dec 2021 00:00:00 GMT http://dspace.zu.edu.ly/xmlui/handle/1/1722 2021-12-31T00:00:00Z