Volume 28, No. 1 (2022)
Articles
SCANNING ELECTRONIC MICROSCOPE EVALUATION OF A TUNISIAN SOIL
MOHAMED ABDELWAHEB(1), VALENTIN NEDEFF(2,3), SONIA DRIDI-DHAOUADI(1), EMILIAN MOSNEGUTU(*2), ALEXANDRA-DANA CHITIMUS(2)
This work present a soil analysis by scanning electronic microscope. The soil was collected from Tunisia. The analysis of soil show the highly presence of carbon and oxygen. The carbon is well used to retain heavy metals and pesticide. The soil presents also a high level of lead, this level present a high risk of water resource pollution.
A COMPUTER PROGRAM FOR ANALYZING CONCRETE MIXTURE EXPERIMENTS BASED ON OSADEBE’S REGRESSION MODEL
IFEANYI AGWUOCHA(1), UCHECHUKWU COLLINS ANYA(1), CHIOMA TEMITOPE GLORIA AWODIJI(*2), LAWRENCE ETTU(1)
The Osadebe’s regression model is associated with lots of strenuous mathematical computations. In this research work, a MATLAB based computer program, named MIX-PRE, was formulated for analyzing concrete mixture experiments using the Osadebe’s regression model. It was tested by comparing results obtained from it to previous studies by Anya and Okere. The highest percentage difference between strength results from MIX-PRE and from these studies was about 3%. The % differences for all other parameters studied were close to zero showing little contrast in the predicting ability of MIX-PRE when compared to the direct use of the Osadebe’s regression model.
FERMENTATIVE-MODIFICATION OF SORGHUM AND MILLET BIOPOLYMERS: IMPACT ON FUNCTIONAL PROPERTIES, PROXIMATE COMPOSITION, AMINO ACIDS AND PROTEIN QUALITY OF MODIFIED FLOURS
SULEIMAN YUSUF BAGIREI(*1), IROH NKAMA(2), MAMUDU HALIDU BADAU(3), YAHAYA SAYYADI MOHAMMAD(1)
Fermentation is being used in the preparation of cereal-based foods to impart changes that can influence the character of the final product, but the processes of are tedious, unhygienic and labor intensive. Scientific improvements can facilitate product standardization, specification, safety and availability. Fermentative modification of the sorghum and millet grains biopolymer was achieved by natural fermentation at 34 oC for 36hours, with the fermentation water being changed every 12 hours. The grains were decanted and dried in a solar dryer at 41 oC, ground and sieved through a 300 μm sieve, while laboratory analyses carried out by standard methods. The functional properties, proximate composition, amino acids profile and protein quality indices of the flours were determined using standard methods. The process led to reduction in functional properties and proximate composition but carbohydrate and energy values were not affected while protein contents were increased by 7.5 % for sorghum and 9.7 % for millet. Reduction of 11.5 % and 17.2 % in leucine and phenylalanine contents respectively were recorded in sorghum, but in millet the values increased by 15.8 % and 6.6 % respectively. There were 2.9 % and 20.6 % increase in lysine and tryptophan contents in sorghum and a decrease of 13.5 % and 7.7 % respectively in millet. There were increases in histidine, isoleucine, methionine, threonine, and valine.
THE OPPORTUNITY OF USING CLOUD-BASED COMPUTING IN NUMERICAL SIMULATIONS ON STRUCTURAL ANALYSIS - CASE STUDY
VLAD ANDREI CIUBOTARIU(*1), COSMIN GRIGORAS(1), CRINA MARIA RADU(1), CATALIN NICOLAE TAMPU(1), VALENTIN ZICHIL(1)
To make the most accurate behavioral assessments of mechanical parts, engineers rely heavily on numerous software solutions. These software solutions are able to solve more or less complex problems with a fairly high degree of accuracy and similarity to physical experiments. The common feature of these software solutions is that they need generous resources from the computer on which they are installed. Can't it be done differently? One possible answer may be the use of cloud-based solutions. The main purpose of this paper is to make a comparison and find the limitations of such a solution relative to the established ones in the field of finite element analysis. Therefore, this paper is a case study in which an industrial component – beam bracket – is subjected to a structural analysis on three different software solutions. The reference systems are: ANSYS, a solution dedicated to finite element analysis and SolidWorks Simulation, a solution often used in industry for the assessment of mechanical structures. The cloud-based solution is SimScale, a software product based on open-source codes: Code_Aster and CalculiX.
SOME COMPARATIVE OPINIONS REGARDING THE WORKING OF FIBERS AND MATRIX ON AXIAL STRESS LIMIT. MATRIX WITH LONGER FIBER EXTENSIONS
RADU I. IATAN(*1), ANDREEA - SILVIA NITU(2), MIHAI STATESCU(3), ELENA SURDU(1), DANA-CLAUDIA FARCAS - FLAMAROPOL(1), MELANIA CORLECIUC (MITUCA)(4), COSMIN CIOCOIU(1)
This paper falls within the current scientific and technical research concerns related to structures made of long fiber composite materials. An essential problem is the co-operation of the matrix material with that of the fibers in the composite layers under the action of external loads, until the structure is damaged. In the present case, the case is taken into account if the material of the matrix is characterized by elongations superior to those of the fibers, so that they will break before the damage of the matrix. The linear-elastic behavior of the fibers is considered until their rupture and, obviously, the destruction of the composite.
MAGNESIUM ALLOY AZ31B FORMING LIMIT CURVE USING THE NAKAZIMA TEST
AUGUSTIN JITARU(1), COSMIN CONSTANTIN GRIGORAȘ(*1), GHEORGHE BRABIE(1), ANA-MARIA ROȘU(1), LUCIAN-MARIUS ROȘU(1)
The behaviour of a metal sheet when forming can be predicted with accuracy if the forming limit curve is known (FLC). Generating an FLC is a two-step process that involves forming the material blanks and measuring the strain. This can be done by using the Marciniak or Nakazima tests. In this experimental paper, the Nakazima test was used and is conducted using a hemispherical punch, retaining plate, and draw beads, to prevent the blank from slipping, along with the ARAMIS digital image correlation (DIC) system, used for measuring. Metal sheets of magnesium alloy AZ31B were used, with thicknesses of 0.5 mm and 1.0 mm. The settings of the testing equipment have been selected to allow the material to break at different strains: from uniaxial to biaxial stretches. Each specimen represents specific stress in the strain limit diagram. The geometries of the material and its thicknesses have the same leading role in creating tensions. Compared to the tensile compression test, this test confirms better formability of sheets with a thickness of 0.5 mm.
SPECTRUM OCCUPANCY MEASUREMENT AND ANALYSIS AT OSUN STATE UNIVERSITY CAMPUS, OSOGBO, NIGERIA
HAMMED OYEBAMIJI LASISI(1), BOLATITO FATIMAH ADERINKOLA(*2), FUNMILOLA MARGARET ADEAGBO(1)
The rapid growth of new wireless communication applications and services has increased the demand for effective radio spectrum usage. However, present spectrum allocation policy has left some bands unoccupied. Through spectrum measurement, unoccupied spectrum can be identified and reallocated to unlicensed users without interfering with licensed users. This paper presents spectrum occupancy measurement of UHF TV bands from 470 MHz – 870 MHz conducted at six different locations in Osun State University, main campus, Osogbo. The results revealed that the spectrum occupancy values for the locations considered are: 16.6%, 11.9%, 18.9%, 23.1%, 17.7% and 19.4% respectively for locations 1, 2, 3, 4, 5 and 6. Only 17.9% of the spectrum, on the average, is effectively utilized. This indicated that large portion of the spectrum is unoccupied, and cognitive radio, stands a good chance of being deployed in the examined bands.
MODELING AND SIMULATION OF PROXIMITY SENSORS
SORIN EUGEN POPA
In the context of the pandemic caused by the COVID-19 virus, the transition to online education was forced. Also, the laboratory works from the engineering disciplines must be adapted to the online environment. This paper presents the study of infrared proximity sensors, raising the operating characteristic and comparing it with that provided by the sensor manufacturer. The transfer function of the sensor will be determined annalistically and will be compared with the one obtained from the simulation. At the end, the conclusions we can draw will be presented.
DEVELOPMENT OF CASHEW NUT PROCESSING MACHINE
OYETUNJI ROPO(1), AKINFENWA AYOBAMI(*2), ADEWUYI FESTUS(1)
The stress, injuries and hazardous effects incurred during processing of cashew nut is huge. This work considered the design and development of cashew nut processing machine to help farmers improve the process efficiency. Cashew nuts were fed into the machine containing the heating and shelling chamber. The designed machine dried, roast and shelled the nuts. The shelled cashew nuts were then cooled, and kernels separated from shell manually. An efficiency of 80% was determined in terms of number of whole kernel recovery, roasting and cracking time.
APPROACH TO ADJUSTING LAMPS’ HEIGHTS AND ANGLES: DESIGN AND IMPLEMENTATION OF AN ELEVATING DEVICE FOR ILLUMINATION IN SLEDGE TESTS
ZHE WEI(*1), HAITAO ZHANG(1), JINLONG GONG(2), YI QIANG(2), FADHLIYAH MUHAMMAD YUSUF(3)
In order to achieve the aim of adjusting heights and angles of lamps in sledge tests, detailed requirements were analyzed, and the implementation scheme was devised. The prototype of the elevating device was designed to validate the effect. Both the power circuit and the control circuit were researched on to power and control the 4 3-phase asynchronous motors respectively. An effective solution was provided to the adjustment of the essential parameters in sledge tests’ illumination. Manual control and remote control modes were both designed and employed to make the necessary adjustments possible. On-site application validated that the elevating device was effective and could be used to adjust parameters relevant with lamps’ spatial positions.