Volume 25, No. 2 (2019)

DETERMINATION OF ACETIC AND PROPANOIC ACIDS CONCENTRATION IN NIGERIAN KEROSENE

ISAAC KAYODE ADEGUN(*1), OLUWATOSIN ADEDAMOLA ADESOYE(1), ADIO-YUSUF SELIA IYAGBA(2), DAVID ADEBOLA ADETORO(1)

The paper aims to determine acetic and propanoic acid concentrations in some selected samples of kerosene used in Nigeria. The Armfield Liquid-Liquid Extraction Unit was employed to carry out the study. Distilled water and kerosene samples from five different sources were used for the investigation. The parameters taken into consideration during the course of the experiments were time, thermal conductivity, temperature, flow rates and concentration of the acid. It was deduced from the research that the temperature and the conductivity decreased with significant decrease in concentration of the acid and vice versa. The results gotten from the extraction of the kerosene samples also showed that sample A, sample D, and sample E did not contain acetic acid while sample B and sample C had traces of acetic acid, with sample C having traces of propanoic acid. After comparing the values with the standard classification of acetic acid, it was discovered that the concentration of both acetic and propanoic acid in the samples were not significantly sufficient to harm human beings.

ROUTE FIRST-CLUSTER SECOND METHOD FOR PERSONAL SERVICE ROUTING PROBLEM

MELİKE KÜBRA EKİZ(*1, MUHAMMET BOZDEMİR(2), BURCU OZCAN TÜRKKAN(1)

The Vehicle Routing Problem (VRP), which has many sub-branches, is a difficult problem that cannot be solved using classical methods. This study includes a case study for Service Routing Problem, which is one of the sub-branches of VRP. The case study is a problem of determining service routes for staffs of a company. In this context, we first assigned the employees to the stations, and then we reached a solution using the route first-cluster second heuristic method. We used the Genetic Algorithm (GA) to improve the route and compared the results by creating different scenarios in clustering methods.

MATERIALS FOR AUTOMOTIVE INDUSTRY AND THEIR INFLUENCE ON THE DYNAMICS OF A CAR CRASH

NAVODARIU NICOLAE(*1), CIOCOIU ROBERT(1), TRANTE OCTAVIAN(1), ANTONIAC VASILE IULIAN(1)

The aim of this research was to determine the influence of the metallic materials characteristics on the dynamics of a car crash. Another important aspect is that the metallic parts are sometimes repaired after minor accidents and this fact influence strongly the mechanical characteristics and their influence on the dynamics of a car crash. In this paper, we analyze the mechanical characteristics of thin steel plates repaired by local heating associated with plastic deformation (similar to hot working) and cold straightening (similar to local cold working) for automotive side and door panels made of structural steel. Thin sheet plates, 0.9mm thickness, were deformed by impact and repaired by local heating using the flame and induction heating then plastically deformed while hot as well as straightened without heating. The heat repaired samples were studied by light microscopy to determine microstructure change and samples were tensile tested to determine their mechanical characteristics. Local excessive grain growth generates anisotropy, the assembly behaves as a composite material with regions that show significant plastic deformations while others little or no deformations at all. Without procedures adjusted to each material repairs involving heating are to be avoided, cold working should be employed when replacement is not possible.

VIBRATIONAL CASE STUDY FOR THE MOLD OSCILLATOR WITH HYDRAULIC SERVO SYSTEM

YONGHUI PARK(*1), CHANGWOO LEE(2, 3), DONGWOOK KIM(2, 3)

We have conducted sensitivity analysis to investigate the two-hydraulic-servo system for the mold oscillator. By modelling mathematical models for operating fluid flow to control a hydraulic cylinder, we changed design parameters and environment conditions including friction, additional spring stiffness and fluid leakage. From the one-hydraulic servo system to the two-hydraulic cylinder, modal analysis was conducted to figure out dynamic characteristics of the real system. Especially, we categorized important natural mode shape. When the system was excited into the natural frequency, the 1st mechanical natural frequency could cause a pressure gain by reducing internal pressure of a hydraulic cylinder, but other natural frequencies were critically dangerous by generating imbalance, over-vibration and distortion. By comparing the results to the experimental data, we could find a dramatic pressure drop near 3 Hz oscillation when the system has the 1st mechanical natural frequency 2.499 Hz. Also, the system has the imbalance near 6 Hz oscillation when the system has 2nd mechanical natural frequency 5.446 Hz. Based on these fact, we have suggested some tips to oscillate a mold efficiently and safely.

NONCONVENTIONAL TECHNIQUE FOR PRODUCING HIGH MECHANICAL STRENGTH GLASS FOAM FROM GLASS WASTE

LUCIAN PAUNESCU(*1), MARIUS FLORIN DRAGOESCU(1), SORIN MIRCEA AXINTE(1, 2), ANA CASANDRA SEBE(3)

In the work experimental results on the manufacture of glass foam with high mechanical strength from glass waste are presented. By replacing the usual conventional energy source with a nonconventional energy (electromagnetic waves) the heating efficiency allows a fast and economical manufacturing process. Calcium carbonate as a foaming agent and an addition of sodium silicate (aqueous solution) as a binder were used. By their physico-mechanical and morphological features (0.40-0.66 g/ cm3 the apparent density, 0.054-0113 W/ m·K the thermal conductivity, 2.2-6.3 MPa the compressive strength, below 1.2 % the water absorption and under 2 mm the pore size), the foams are appropriate for their use as replacer of existing similar building materials on the market.

CINEMATICAL ANALYSIS OF THE PRE-TAKING AND PRE-COMPACTING MECHANISMS OF SOME GARBAGE TRUCKS

GHEORGHE VOICU(*1), MIRCEA LAZEA(1), BIANCA-STEFANIA ZABAVA)1), PAULA TUDOR(1), VICTOR MOISE(1)

The paper presents several constructive variants of power systems and makes a comparative analysis of them, both constructively and functionally. The kinematic analysis of a bar and lever mechanism is also realized, which is used in a wide range of compaction by translation. Elucidation of the movement of the working organs of these mechanisms is necessary for a good understanding of their operation, but especially for redesigning and improving their functional parameters for a low loss and low energy operation.