Formation and anisotropic magnetoresistance of Co/Pt nano-contacts through aluminum oxide barrier

We report on the observation of anisotropic magnetoresistance (AMR) in vertical asymmetric nano-contacts (NCs) made through AlO$_x$ nano-oxide layer (NOL) formed by ion-assisted oxidation method in the film stack of Co/AlO$_x$-NOL/Pt. Analysis of NC formation was based on \emph{in situ} conductive atomic force microscopy and transmission electron microscopy. Depending on the purity of NCs from Al contamination, we observed up to 29% AMR ratio at room temperature

Teaching English in Elqubba Primary Schools: Issues and Directions

The Libyan Ministry of Education has taken important steps to introduce English from the 1st grade (age 6) since autumn semester 2018/2019, yet without taking into considerations the issues that will be faced in teaching English in primary schools. This study, therefore, aimed to identify the issues encountered in the teaching of English from the 1st grade to the 4th grade in primary schools in Elqubba, a city in Eastern Libya and how to overcome these issues. Data were collected through focussed observations and semi-structured interviews. The findings revealed that crowded classrooms, lack of teaching tools and equipments, insufficient exposure to the target language, extensive use of Arabic language, some deficiencies in "English for Libya" coursebooks, poor knowledge of teaching methods, and non-English major teachers were the challenges faced in teaching English. Directions are proposed to overcome these issues

Finite Element Analysis of Spring Back Phenomenon in V- bending of Sheet Metals

The objective of this study is to determine numerically, the effect of different parameters on springback phenomenon during sheet metal forming process. Nonlinear numerical simulation was performed using a finite element commercial MSC MARC software. Numerical results were verified with available experimental data obtained from the literature. Four parameters namely, the effect of material type, sheet thickness, friction and punch radius were evaluated in springbak phenomena. In evaluating the effect of material types on springback phenomenon, high tensile steel (HTS), mild steel (MS), deep drawing steel @DS) and commercially pure aluminium (CA) were used. The computational results showed that the value of springback is influenced by type of material.Deep drawing steel displayed the highest value of springback (3.48"), while the lowest springback value was recorded for mild steel (2.06"). The effect of friction coefficient on springback phenomenon was determined using different friction coefficient ranging between 0.1 and 0.5 with increment of 0.1. Friction coefficient 0.5 displayed the highest value of springback (3.8") and the lowest value of springbak (2.4") was recorded for friction coefficient 0.1 which means that springback increases as friction coefficient increases. Sheets have thickness of (3mq 5mm, 8.3rnrn, lOmm and 12.8mm were evaluated for springback phenomenon. The results showed that the springback values decreases as sheet thickness increases. 3 mm sheet computed to have the highest value of springback (7.65"), 12.8 mm sheet had the lowest springback value (2.88"). Finally, (3mm, 5mm, 8mm, lOmm and 12mm) punch radius were also evaluate to study their effect on developed springback,. The results showed that as the punch radius increases the springback vaIues increases. The punch with 12mm radius exhibited the highest value of springback (5.84") and the lowest springback value of lo was computed for punch with radius of 3mm

Acquisition of the verb movement parameter in English by adult Arabic speakers

This study investigates the acquisition of the verb movement parameter in English by adult Arabic-speaking learners of English as a Second Language (ESL) 1 . English and Arabic differ in the settings they adopt for the verb movement parameter. English is [-strong], while Arabic is [+strong]. Accordingly, the placement of the verb with respect to negation, adverbs and floating quantifiers (FQs) in English are considered difficult to acquire for adult Arabic ESL learners. In order to examine the nature of adult Arabic ESL learners’ interlanguage (IL) grammar at the L2 ultimate attainment level as well as the extent to which the adult Arabic ESL learners can reset the verb movement parameter and correctly place the verb with respect to negation, adverbs and FQs in finite and non-finite contexts with lexical and auxiliary verbs, an oral production task was conducted with 77 adult Arabic ESL learners who were subdivided into three proficiency levels (lower-intermediate, upper-intermediate and advanced). The results reveal that the Arabic ESL learners, even at ultimate attainment level, have great difficulty in resetting the parameterized property associated with the verb movement. These results support the Failed Functional Features Hypothesis (FFFH) (Hawkins and Chan, 1997) which proposes that post-childhood adult L2 learners are unable to reset parameters from their L1 values to the L2 settings where these differ from the L1 setting

Resistance of built-up cold-formed steel channel columns filled with concrete

Cold-formed steel (CFS) channel infilled with concrete could increase its ability and stiffness by avoiding failure due to local buckling. Besides, the built-up bolted CFS channel column could serve as permanent formwork, decreased waste material and yet increase economical construction. This study aims to investigate the strength of built-up CFS channel columns infilled with concrete. Two CFS channel sections are situated face to face, connected and strengthen by using M10 bolts and nuts. Then, the 900 mm built-up column is filled with normal concrete of grade C30. Six samples with different end and central bolt spacing were tested. Material properties of CFS and concrete, and the mechanical properties of bolts are also investigated. From the result, the column with concrete on shortest end bolt spacing gave highest ultimate load and reported 68 – 78 % different when compared to similar column without concrete infilled. The failure mode of the column is global buckling and supports yielding, and the concrete is failed due to cracking and breaking. Equation of the relationship between bolt spacing either at the end or central and ultimate load is established

Strengthening method and structural performance of cold-formed cut-curved steel under compression

Cold-formed steel section (CFSS) is a popular material in the steel structure that has been recognised in construction work. CFSS with curved section is a new section that proposed in the CFSS and still being studied by researchers. Steel curved section, whether by using hot-rolled or cold-formed steel become essential and significant in the design that be suited by the architectural demand. For this reason, the CFSS is recommended to provide the curve in the structure and dispute the use of the hot-rolled steel. In the study, the CFSS is curved by using a clamp, small bender and welding machine. Through this process, CFSS with cut-curved (CFSS-C) is strengthened by welding in particular location at flange and web. The CFSS-C are established into five specimens with different of welding location and added with one normal specimen (CFSS-N) as a control specimen. The CFSS is tested for the structural performance of the column specimens with the height, 1000 mm under compression load and lastly the suitable strengthens method with highest of ultimate load is selected. From the testing, CFSS-C4 is reported to decrease about 32.26 % when compared with normal specimen

Isolation and characterization PHB producing bacteria from waste cooking oil using pomegranate molasses as carbon source

Polyhydroxyalkanoates (PHAs) are biopolymers which have similar characteristics with petrochemical plastic but a step better due to its biodegradable property. Polyhydroxybutyrate (PHB) producing bacteria from waste cooking oil (WCO) was isolated and characterized based on its morphological and biochemical properties. Only one strain was isolated from different samples of WCO collected from different restaurants. The isolated bacterium was related to Bacillus thuringensis LMA which was identified and characterized using morphological, biochemical and molecular biology methods. In order to detect the PHAs granules, the strain of bacteria was first screened with Sudan Black B staining and Nile Blue A staining was done for further confirmation. During the stationary phase, the LMA strain was subjected to 5 % (w/v) of pomegranate molasses (carbon source). Samples were collected for two time of the incubation period for detection of PHAs using Sudan Black B staining. The PHAs production accumulated up to 50.4% of its cell dry weight. The PHAs produced was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance Spectroscopy (NMR). By using these two methods, it was confirmed that the polymer produced by the isolated bacteria is Polyhydroxybutyrate (PHB) polymer