185 research outputs found
The relation between student behaviours in group presentations and their teamwork modalities using Belbin and MBTI analysis
This research paper aims to investigate the relationship between learners’ profiles as analysed according to MBTI and Belbin and their behaviour during group presentations while not being the active presenter. This paper is part of a research study in the field of video tagging as a mechanism for analysing individual behaviour in learning activities. As part of this study, the authors analysed videos of student group presentation and associated behavioural patterns to individual student profiles as produced by the Belbin and MBTI analysis models. The aim of the study was to identify how social and teamwork characteristics of individual learners can relate to certain behaviours. Such relations would help to better assess video content of learning activities including meetings and presentations. A primary aim of the study is to identify associations between human behaviour and individual’s teamwork characteristics. Such associations could facilitate the judgment of learners’ ability to work in a team. The study included quantitative research methods for analysing videos in combination with personality profiling analysis, with emphasis on social and teamwork activities. The Belbin and Myers–Briggs Type Indicator (MBTI) models were used for the purpose of this study. Furthermore, the behavioural patterns monitored during the video analysis included ‘eye contact with presenter’ and ‘eye focus out’ as the most prominent observable behaviours. The paper’s conclusion is that based on the analysis results, learners classified as Coordinators (Belbin) or Virtuosos (MBTI) are less likely to lose focus while they are not presenting, and students classified as Monitor Evaluators (Belbin) or Logisticians (MBTI) are more likely to look and take care of their team members while presenting
ELECTROCHEMICAL AND CHEMOMETRIC DETERMINATION OF DORZOLAMIDE AND TIMOLOL IN EYE DROPS USING MODIFIED MULTIWALL CARBON NANOTUBE ELECTRODE
Objective: This work is focused on the construction of simple and sensitive electrochemical sensor for quantitative determination of dorzolamide (DOR) and timolol maleate (TIM). This method is based on the incorporation of multiwall carbon nanotubes (MWCNT) into the carbon paste electrode which improve the characteristics of the electrode.Methods: The electrochemical response of modified electrode was based on voltammetric oxidation, using cyclic voltammetry (CV) and impedance spectroscopy (EIS). The structural morphology of the surface modified electrode was characterized by scanning electron microscope (SEM). Quantitative analysis for each of the two compounds in a mixture has been examined by using of chemometric tools for resolving overlapping signals. The prediction performance of the chemometric method was analyzed by principal component regression (PCR) and partial least square (PLS).Results: Fractional factorial design was constructed from set of synthetic mixtures of two drugs in concentration ranges of 0.05 to 1.6µg/ml for DOR and 1.5-20 µg/ml for TIM. Under optimum experimental conditions, DOR and TIM gave rectilinear response over the concentration range of 0.072-1.88 µg/ml and 1.16-20.84 µg/ml, respectively. The limit of detection (LOD) was found to be 0.098 and 1.025 µg/ml, for DOR and TIM, respectively. It found that the % of relative prediction error (RPE) was acceptable and satisfactory.Conclusion: In these work, for the first time, a new voltammetric simultaneous method developed for a rapid and efficient determination of DOR and TIM from eye dropper sample at nano modified electrode with satisfactory results. These results indicate that MWCNT holds great promise in practical application
Serum Leptin and Bone Mineral Density in Hemodialysis Patients with or without Liver Diseases
Introduction: Leptin is a hormone secreted by adipocytes that plays an important role in regulating appetite and energy expenditure. Our aim was to evaluate serum leptin level in hemodialysis (HD) patients with or without chronic liver disease (CLD) and study the relationship between serum leptin level and bone mineral density in these groups of patients. Methods: we recruited 20 healthy volunteers as controls (group I), 20 patients on regular HD with normal liver function (group II), 20 CLD patients with normal kidney function (group III) and 20 patients on regular HD with CLD (group IV). We measured serum calcium, phosphorus, parathyroid hormone (PTH), total alkaline phosphatase (ALP), serum leptin, 24-hours urinary hydroxyproline and bone mineral density (BMD) of the lumber spine and femoral neck by DEXA scan. Results: Serum leptin level was significantly higher (P <0.001) in HD patients and CLD patients compared to controls. Its level was also significantly elevated in HD patients without liver disease (group II) compared to patients with CLD who had no renal failure (group III). Urinary hydroxyproline level was increased in both HD patients and CLD patients. We detected a positive correlation between serum leptin level and urinary hydroxyproline in all patient groups. There was a significant decrease in BMD in HD and CLD patients. BMD was significantly lower in HD patients without CLD compared to HD patients with CLD. There was a significant negative correlation between serum leptin level and BMD in CLD patients without renal disease but not in other groups (r = - 0.6, P = 0.01). Conclusion: Serum leptin is elevated in HD patients with or without liver disease and in CLD patients. Serum leptin level is inversely correlated with BMD in CLD patients without renal disease.Keywords: Bone Mineral Density; Cirrhosis; Chronic Liver Disease; Hemodialysis; Lepti
The transverse shear deformation behaviour of magneto-electro-elastic shell
Compared to the large number of possible magneto-electro-elastic shell theories, very few exact solutions determining the in-plane stresses, electric displacements and magnetic inductions are possible. While, solving the magneto-electro-elastic shell equations in terms of thermo-magneto-electro-elastic generalized field functions on arbitrary domains and for general conditions exactly are not always possible. In the present work, a linear version of magneto-electro-elastic shell with simply supported boundary conditions, solved exactly, provided that the lamination scheme is cross-ply or anti-symmetric angle-ply laminates. The exact solution that introduced herein can measure the in-plane stresses, electric displacements and magnetic inductions. It also allow for an accurate and usually elegant and conclusive investigation of the various sensations in a shell structure. However, it is important for micro-electro-mechanical shell applications to have an approach available that gives the transverse shear deformation Behaviourfor cases that cannot examine experimentally. An investigated examples were accompanied and noteworthy conclusions were drawn which highlight the issues of the implementation of the exact solution, implication of the effects of the material properties, lay-ups of the constituent layers, and shell parameters on the static Behaviour
The influence of green modification of lignin on the electrochemical properties of biocomposites for industrial applications
It’s a report on a novel approach; preparation and electrochemical properties of modified lignin. Wax and starch were used as natural, green adhesives for enhancing the electrical resistivity of lignin in acidic medium, forming eco-friendly high insulator biocomposite. Scanning electron microscopy (SEM) was used to characterize the fabricated biocomposite. The modified lignin was characterized using Fourier transform infrared (FTIR), while the electrochemical behavior was examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The innovative approach described in this work provides a promising eco- friendly method for lignin modification with highly electrical resistivity and stability with time.Â
Radiation effect on viscous flow of a nanofluid and heat transfer over a nonlinearly stretching sheet
In this work, we study the flow and heat transfer characteristics of a viscous nanofluid over a nonlinearly stretching sheet in the presence of thermal radiation, included in the energy equation, and variable wall temperature. A similarity transformation was used to transform the governing partial differential equations to a system of nonlinear ordinary differential equations. An efficient numerical shooting technique with a fourth-order Runge-Kutta scheme was used to obtain the solution of the boundary value problem. The variations of dimensionless surface temperature, as well as flow and heat-transfer characteristics with the governing dimensionless parameters of the problem, which include the nanoparticle volume fraction ϕ, the nonlinearly stretching sheet parameter n, the thermal radiation parameter NR, and the viscous dissipation parameter Ec, were graphed and tabulated. Excellent validation of the present numerical results has been achieved with the earlier nonlinearly stretching sheet problem of Cortell for local Nusselt number without taking the effect of nanoparticles
Influence of chip serration frequency on chatter formation during end milling of Ti6Al4V
This paper includes the findings of an experimental study on instabilities of the chip formation process during end milling of Ti6Al4V alloy and the influence of these instabilities on chatter formation. It has been identified that the chip formation process has a discrete nature, associated with the periodic shearing process during machining. The chip formed during machining of titanium alloy Ti6Al4V is found to be mainly with primary serrated teeth appearing in the main body of the chip. Secondary serrated teeth resulting from the coagulation of a certain number of primary serrated teeth also happen to appear at the free or constrained edge of the chip, especially when the system enters into chatter. In order to identify the interaction of these chip instabilities with the prominent natural vibration of the machine tools system components, the different mode frequencies of the vibrating components of the system have been identified using experimental and finite element modal analyses, and vibration responses during actual cutting have also been recorded using an online vibration monitoring system. The vibration signals in frequency domain (fast Fourier transform) have been analyzed to identify the chatter frequencies and the peak amplitude values. Chatter was found to occur at two dominant mode frequencies of the spindle. These mode frequencies at which chatter occurred have been compared with the chip serration frequencies in a wide cutting speed range for different conditions of cutting. It has been concluded from these findings that chatter occurs during end milling due to the resonance of the machine tools system component when the frequency of primary serrated teeth formation is approximately equal to the "prominent natural frequency" modes of the system components, which are the two mode frequencies of the VMC machine spindle in this particular case
DNA Fingerprinting, Chemical Composition and Antimicrobial Activity of the Essential Oil isolated from the Fruits of Serenoa repens W. Bartram
The chemical composition of the essential oil obtained from the fruits of Serenoa repens W. Bartram by hydrodistillation has been studied by GC/MS analysis. The analysis of the essential oil revealed the presence of 60 identified compounds (monoterpene and sesquiterpene) oxygenated and non-oxygenated compounds in the oil sample including about 53 compounds which were not reported in GC/MS analysis of the essential oil before. GC/MS analysis revealed 4-(1-methylethyl)-Benzaldehyde to be the major constituent of the essential oil of the fruits 58.56% followed by 2-Caren-10-al and 3-Caren-10-al (11.83% and 2.87%, respectively). So far nothing could be traced concerning the oil biological activity. The antimicrobial sensitivity as well as the MIC against different fungal, gram positive and gram negative strains was carried out. The antimicrobial snsitivity was higher as antifungal followed by the Gram-positive strains, and Gram-negative bacteria strains compared to the positive controls. The essential oil showed high selective antimicrobial potential (MIC 1.95–62.5 μg/mL for bacteria; and MIC 3.9–31.25 μg/mL for fungi). DNA fingerprinting of the cultivated leaves were carried out for authentication of the plant. Keywords: Serenoa repens, essential oil, 4-(1-methylethyl)-Benzaldehyde, Antimicrobial, GC/MS, DNA
Optimization of robust and LQR control parameters for half car model using genetic algorithm
To test the performance of the half car system, two types of controller are used, namely Robust H-infinity control and LQR control. Robust H-infinity and LQR controller is designed to control the suspension system and to reduce the vibrations in the car and to improve handling. A half car model is considered in this research to study the effects in passenger owing to different road profiles. The weights of Robust H-infinity and LQR controller are obtained using Genetic Algorithm on a half car model with two different types of usually existing road disturbance.The design parameters of both the active controller varies with various road profiles. This proves that particular design parameters in Robust and LQR controller do not have the ability to adapt to the variations in road surface. Furthermore, active controllers significantly improve the performance of the system in all aspects when compared to passive system. © 2019 SERSC
Synthesis and some reactions of 4-aroyl and 4-aryl-6-(p-acetamidophenyl)pyridazin-3(2H)-ones
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