Search results for: enhanced diffusion

Authors: A. Binnui, O. Kalinowska-Beszczynska, G. Shaw

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It is postulated that innovative deployment of entrepreneurial activities leads to firm's growth. This paper draws upon the key predictions of the core theories on entrepreneurship and innovation to formulate a conceptual framework which can be used to depict the casual chain of events from which entrepreneurs can manage more innovatively and ultimately deliver higher growth which benefits of the regional and national economies. It examines the key firm-based factors extracted from the theories, namely the characteristics of entrepreneurial hi-tech firms, characteristics of innovating firms, and firm growth dynamics that lead to enhanced economic growth. The framework postulates that the key determinants extracted such as entrepreneurial demographics, firm characteristic, skills and competencies, research and development, product/service characteristics, market development, financial of the firm and internationalization might lead to the survival and long term development of high-technology startups.

Keywords: innovative entrepreneurial activities, entrepreneuship, determinants, growth, hi-technology start-upws

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Authors: Dipali Nagaonkar, Mahendra Rai

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Nanotechnology has experienced significant developments in engineered nanomaterials in the core-shell arrangement. Nanomaterials having nanolayers of silver and gold are of primary interest due to their wide applications in catalytical and biomedical fields. Further, mycosynthesis of nanoparticles has been proved as a sustainable synthetic approach of nanobiotechnology. In this context, we have synthesized silver and silver (core)-gold (shell) bimetallic nanoparticles using a fungal extract of Fusarium graminearum by sequential reduction. The core-shell deposition of nanoparticles was confirmed by the red shift in the surface plasmon resonance from 434 nm to 530 nm with the aid of the UV-Visible spectrophotometer. The mean particle size of Ag and Ag-Au nanoparticles was confirmed by nanoparticle tracking analysis as 37 nm and 50 nm respectively. Quite polydispersed and spherical nanoparticles are evident by TEM analysis. These mycosynthesized bimetallic nanoparticles were tested against some pathogenic bacteria and Candida sp. The antimicrobial analysis confirmed enhanced anticandidal and antibacterial potential of bimetallic nanoparticles over their monometallic counterparts.

Keywords: bimetallic nanoparticles, core-shell arrangement, mycosynthesis, sequential reduction

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Authors: N. S. Achour, M. Hamdaoui, S. Ben Nasrallah

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Wicking and evaporation of water in porous knitted fabrics is investigated by combining experimental and analytical approaches: The standard wicking model from Lucas and Washburn is enhanced to account for evaporation and gravity effects. The goal is to model the effect of gravity and evaporation on wicking using simple analytical expressions and investigate the influence of fabrics geometrical parameters, such as porosity and thickness on evaporation impact on maximum reachable height values. The results show that fabric properties have a significant influence on evaporation effect. In this paper, an experimental study of determining water kinetics from different knitted fabrics were gravimetrically investigated permitting the measure of the mass and the height of liquid rising in fabrics in various atmospheric conditions. From these measurements, characteristic pore parameters (capillary radius and permeability) can be determined.

Keywords: evaporation, experimental study, geometrical parameters, model, porous knitted fabrics, wicking

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Authors: Merle Bischoff, Thomas Gries, Gunnar Seide

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Nanocomposites have become more and more important as the implementation of nanoparticles in polymer allows additional functions in common industrial parts. Especially in the fabrication of filaments or fibres nanomodification is important, as only very small fillers can be added to the very fine fibres (common diameter is 20 µm, fine filament are 1 µm). Discharging fibres, conductive fibres, and many other functional fibres raise in their importance nowadays. Especially the dispersion quality is essential for the final enhancement of the filament propertied. In this paper, the dispersion of carbon nanoparticles in polymer melt is enhanced by a newly developed sonication unit of ITA and BANDELIN electronic GmbH & Co. KG. The first development steps of the unit fabrication, as well as the first experimental results of the modification of the dispersion, are shown. Special focus will be laid on the sealing of the new sonication unit as well as the positioning and equipment size when being implemented in an existing melt spinning unit. Furthermore, the influence on the thereby manufactured nano-modified filaments will be shown.

Keywords: dispersion, sonication, carbon nanoparticles, filaments

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Authors: W. J. Kim

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The behaviors of the recovery stress and strain of an ultrafine-grained Ni-50.2 at.% Ti alloy prepared by high-ratio differential speed rolling (HRDSR) were examined by a specially designed tensile-testing set up, and the factors that influence the recovery stress and strain were studied. After HRDSR, both the recovery stress and strain were enhanced compared to the initial condition. The constitutive equation showing that the maximum recovery stress is a sole function of the recovery strain was developed based on the experimental data. The recovery strain increased as the yield stress increased. The maximum recovery stress increased with an increase in yield stress. The residual recovery stress was affected by the yield stress as well as the austenite-to-martensite transformation temperature. As the yield stress increased and as the martensitic transformation temperature decreased, the residual recovery stress increased.

Keywords: high-ratio differential speed rolling, tensile testing, severe plastic deformation, shape memory alloys

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Authors: Hadjer Didouh, Mohammed Hadj Meliani, Izzaddine Sameut Bouhaik

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This study employs a multidisciplinary approach to investigate the intricate processes governing biofilm-surface interactions. Results indicate that surface properties significantly influence initial microbial attachment, with materials characterized by increased roughness and hydrophobicity promoting enhanced biofilm adhesion. Moreover, the chemical composition of materials plays a crucial role in impacting the development of biofilms. Environmental factors, such as temperature fluctuations and nutrient availability, were identified as key determinants affecting biofilm formation dynamics. Advanced imaging techniques revealed complex three-dimensional biofilm structures, emphasizing microbial communication and cooperation within these networks. These findings offer practical implications for industries operating in crude oil environments, guiding the selection and design of materials to mitigate biofilm-related challenges and enhance operational efficiency in such settings.

Keywords: biofilm adhesion, surface properties, crude oil environments, microbial interactions, multidisciplinary investigation

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Authors: Rita Gill Singh, Alex Chun Koon, Cindy Sing Bik Ngai, Joanna Wen Ying Ho, Mei Li Khong, Enoch Chan, Terrence Lau

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Although humour is viewed as a beneficial element in teaching, there has been little attempt to systematize humour in teaching, possibly because it is difficult to teach someone to be humorous. This study integrated planned humour pedagogical approach into teaching and learning activities and examined the effect of systematically planned humour on students’ engagement and learning in different courses. Specifically, appropriate types of humour (i.e. analogy, absurdity and wordplay) and incorporation methods and frequency were systematically integrated into the lessons of courses at some higher education institutions in Hong Kong. The results showed that the planned humour pedagogical approach increased student engagement, as well as enhanced learning and motivation while reducing students’ stress. The pedagogical implications of this study will be useful for researchers, practitioners, and educators.

Keywords: higher education, pedagogy, humour, student engagement, learning, motivation

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Authors: Atousa Ataieyan, Salvador A. Gomez-Lopera, Gennaro Sepede

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Today, due to the growing urban population and consequently, the increasing water demand in cities, the amount of contaminants entering the water resources is increasing. This can impose harmful effects on the quality of the downstream water. Therefore, predicting the concentration of discharged pollutants at different times and distances of the interested area is of high importance in order to carry out preventative and controlling measures, as well as to avoid consuming the contaminated water. In this paper, the concentration distribution of an injected conservative pollutant in a square reservoir containing four symmetric blocks and three sources using Finite Volume Method (FVM) is simulated. For this purpose, after estimating the flow velocity, classical Advection-Diffusion Equation (ADE) has been discretized over the studying domain by Backward Time- Backward Space (BTBS) scheme. Then, the discretized equations for each node have been derived according to the initial condition, boundary conditions and point contaminant sources. Finally, taking into account the appropriate time step and space step, a computational code was set up in MATLAB. Contaminant concentration was then obtained at different times and distances. Simulation results show how using BTBS differentiating scheme and FVM as a numerical method for solving the partial differential equation of transport is an appropriate approach in the case of two-dimensional contaminant transfer in an advective-diffusive flow.

Keywords: BTBS differentiating scheme, contaminant concentration, finite volume, mass transfer, water pollution

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Authors: Saleh H. Abud, Z. Hassan, F. K. Yam

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Characteristics of MSM photodetector based on a porous In0.08Ga0.92N thin film were reported. Nanoporous structures of n-type In0.08Ga0.92N/AlN/Si thin films were synthesized by photoelectrochemical (PEC) etching at a ratio of 1:4 of HF:C2H5OH solution for 15 min. The structural and optical properties of pre- and post-etched thin films were investigated. Field emission scanning electron microscope and atomic force microscope images showed that the pre-etched thin film has a sufficiently smooth surface over a large region and the roughness increased for porous film. Blue shift has been observed in photoluminescence emission peak at 300 K for porous sample. The photoluminescence intensity of the porous film indicated that the optical properties have been enhanced. A high work function metals (Pt and Ni) were deposited as a metal contact on the porous films. The rise and recovery times of the devices were investigated at 390 nm chopped light. Finally, the sensitivity and quantum efficiency were also studied.

Keywords: porous InGaN, photoluminescence, SMS photodetector, atomic force microscopy

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Authors: Francys Souza, Alberto Ohashi, Dorival Leao

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We present a general solution for finding the ε-optimal controls for non-Markovian stochastic systems as stochastic differential equations driven by Brownian motion, which is a problem recognized as a difficult solution. The contribution appears in the development of mathematical tools to deal with modeling and control of non-Markovian systems, whose applicability in different areas is well known. The methodology used consists to discretize the problem through a random discretization. In this way, we transform an infinite dimensional problem in a finite dimensional, thereafter we use measurable selection arguments, to find a control on an explicit form for the discretized problem. Then, we prove the control found for the discretized problem is a ε-optimal control for the original problem. Our theory provides a concrete description of a rather general class, among the principals, we can highlight financial problems such as portfolio control, hedging, super-hedging, pairs-trading and others. Therefore, our main contribution is the development of a tool to explicitly the ε-optimal control for non-Markovian stochastic systems. The pathwise analysis was made through a random discretization jointly with measurable selection arguments, has provided us with a structure to transform an infinite dimensional problem into a finite dimensional. The theory is applied to stochastic control problems based on path-dependent stochastic differential equations, where both drift and diffusion components are controlled. We are able to explicitly show optimal control with our method.

Keywords: dynamic programming equation, optimal control, stochastic control, stochastic differential equation

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Authors: Zain Khan, Steve Ahn, Kathy Monypenny, James Fink

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In Australian public hospitals, there were approximately 34,000 reported inpatient falls between 2015 to 2016. The gold standard for diagnosing intracranial injury is non-contrast enhanced brain computed tomography (CTB). Over a three-month timeframe, a total of one hundred and eighty (180) falls were documented between the hours of 4pm and 8am at a large metro hospital. Only three (3) of these scans demonstrated a positive intra-cranial finding. The rationale for scanning varied. The common indications included a fall with head strike, the presence of blood thinning medication, loss of consciousness, reduced Glasgow Coma Scale (GCS), vomiting and new neurological findings. There are several validated tools to aid in decision-making around ordering CTB scans in the acute setting, but no such accepted tool exists for the inpatient space. With further data collection, spanning a greater length of time and through involving multiple centres, work can be done towards generating such a tool that can be utilized for inpatient falls.

Keywords: computed tomography, falls, inpatient, intracranial hemorrhage

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Authors: Siti Helmyati, Euis Nurdiyawati, Joko Susilo, Endri Yuliati, Siti Fadhilatun Nashriyah, Kurnia Widyastuti

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Background: Iron fortification is one of the most effective and sustainable strategies to overcome anemia. It contradictively, has negative effect on gut microbiota balance. Pathogenic bacteria required iron for their growth. The iron source have greatly affect iron absorption in the intestine. Probiotic can inhibit the growth of pathogen. Lactobacillus plantarum Dad 13, Indonesian local isolate provides many benefits for health while fructo-oligosaccharides (FOS) provides selective substrates for probiotics’ growth. Objective: To determine the effect of iron fortification (NaFeEDTA and FeSO4) on antibacterial activity of synbiotic fermented milk. Methods: The antibacterial activity test was performed using the disc diffusion method. Paper discs were soaked in three kinds of synbiotic fermented milk, which are: 1) fortified with NaFeEDTA, 2) FeSO4 and 3) control. Escherichia coli was inoculated on nutrient agar medium. The ability of inhibition was shown by the formation of clear zone around the paper disc and measured in diameter (mm). Results: Synbiotic fermented milk fortified with iron (either NaFeEDTA or FeSO4) had antibacterial activity against Escherichia coli with diameter of clear zone were 6.53 mm and 12.3 mm, respectively (p<0.05). Compared to control (10.73 mm), synbiotic fermented milk fortified with FeSO4 had similar antibacterial activity (p>0.05). Conclusions: In vitro, synbiotic fermented milk fortified with NaFeEDTA and FeSO4 had different antibacterial activity against Escherichia coli. Iron fortification compound affected the antibacterial activity of synbiotic fermented milk.

Keywords: lactobacillus plantarum Dad 13, FOS, NaFeEDTA, FeSO4, antibacterial activity

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Authors: V. V. Lakshmi, Y. V. S. Annapurna

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Urinary tract infection (UTI) is one of the most common infectious diseases seen in the community. Susceptible individuals experience multiple episodes, and progress to acute pyelonephritis or uro-sepsis or develop asymptomatic bacteriuria (ABU). Ability to cause extraintestinal infections depends on several virulence factors required for survival at extraintestinal sites. Presence of virulence phenotypes enhances the pathogenicity of these otherwise commensal organisms and thus augments its ability to cause extraintestinal infections, the most frequent in urinary tract infections(UTI). The present study focuses on detection of the virulence characters exhibited by the uropathogenic organism and most common factors exhibited in the local pathogens. A total of 700 isolates of E.coli and Klebsiella spp were included in the study. These were isolated from patients from local hospitals reported to be suffering with UTI over a period of three years. Isolation and identification was done based on Gram character and IMVIC reactions. Antibiotic sensitivity profile was carried out by disc diffusion method and multi drug resistant strains with MAR index of 0.7 were further selected.. Virulence features examined included their ability to produce exopolysaccharides, protease- gelatinase production, hemolysin production, haemagglutination and hydrophobicity test. Exopolysaccharide production was most predominant virulence feature among the isolates when checked by congo red method. The biofilms production examined by microtitre plates using ELISA reader confirmed that this is the major factor contributing to virulencity of the pathogens followed by hemolysin production

Keywords: Escherichia coli, Klebsiella sp, Uropathogens, Virulence features.

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Authors: Vasileios Floros

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This article delves into the intricate interplay between leadership styles and teacher satisfaction within the Greek educational framework, underscoring the pivotal role of school leadership in shaping educational success and fostering a conducive school culture. Through a comprehensive analysis, the study explores various leadership theories, the psychological contract between teachers and leaders, and the impact of leadership on teacher job satisfaction and group dynamics within educational institutions. It highlights how leadership efficacy can significantly influence the organizational climate, teacher motivation, and, ultimately, educational outcomes. The findings suggest that effective leadership, characterized by a deep understanding of teacher psychology, thoughtful engagement with the school culture, and strategic application of leadership styles, can lead to heightened teacher satisfaction and enhanced educational performance. This research offers valuable insights for educational policymakers, school leaders, and the broader academic community interested in optimizing leadership practices to foster an enriching educational environment in Greece.

Keywords: educational leadership, teacher satisfaction, school culture, leadership styles, Greek education

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Authors: Zayar Phyo, Ei Chaw Htoon

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In a New-LSB based Steganography method, the Fisher-Yates algorithm is used to permute an existing array randomly. However, that algorithm performance became slower and occurred memory overflow problem while processing the large dimension of images. Therefore, the Text-Based Shuffling algorithm aimed to select only necessary pixels as hiding characters at the specific position of an image according to the length of the input text. In this paper, the enhanced text-based shuffling algorithm is presented with the powered of GPU to improve more excellent performance. The proposed algorithm employs the OpenCL Aparapi framework, along with XORShift Kernel including the Pseudo-Random Number Generator (PRNG) Kernel. PRNG is applied to produce random numbers inside the kernel of OpenCL. The experiment of the proposed algorithm is carried out by practicing GPU that it can perform faster-processing speed and better efficiency without getting the disruption of unnecessary operating system tasks.

Keywords: LSB based steganography, Fisher-Yates algorithm, text-based shuffling algorithm, OpenCL, XORShiftKernel

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Authors: Hamouda M. Mousa, M. Obaid, Chan Hee Park, Cheol Sang Kim

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The rate of copper cementation on iron rod was investigated. The study was mainly dedicated to illustrate the effect of application of electromagnetic field (EMF) on the rate of cementation. The magnetic flux was placed parallel to the iron rod and different magnetic field strength was studied. The results showed that without EMF, the rate of mass transfer was correlated by the equation: Sh= 1.36 Re0. 098 Sc0.33. The application of EMF enhanced the time required to reach high percentage copper cementation by 50%. The rate of mass transfer was correlated by the equation: Sh= 2.29 Re0. 95 Sc0.33, with applying EMF. This work illustrates that the enhancement of copper recovery in presence of EMF is due to the induced motion of Fe+n in the solution which is limited in the range of rod rotation speed of 300~900 rpm. The calculation of power consumption of EMF showed that although the application of EMF partially reduced the cementation time, the reduction of power consumption due to utilization of magnetic field is comparable to the increase in power consumed by introducing magnetic field of 2462 A T/m.

Keywords: copper cementation, electromagnetic field, copper ions, iron cylinder

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Authors: Everdeanne Javier, Kelvin Louie Abat, Alodia Rizzalynn Cabaya, Chynna Allyson Manzano, Vlasta Sai Espiritu, Raniah May Puzon, Michelle Tobler

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Teledermatology is becoming a more popular form of providing dermatologic healthcare worldwide, and it will almost certainly play a larger role in the future. As the current pandemic continues to worsen, Teledermatology is seen as the primary alternative to face-to-face dermatology consultation; therefore, it needs to be enhanced and developed to become as convenient and reliable as it can be for both patients and doctors. This research paper seeks to know the processes used in teledermatology regarding delivery modalities and proper consultation. This study's research design is a Qualitative Descriptive approach to describe further the processes used by teledermatologists. An online survey questionnaire was used to collect data from Teledermatology Clinics in San Fernando City, La Union. Research showed that patients tend to embrace and be pleased with teledermatology as a way of accessing healthcare. On the other hand, clinicians have usually reported positive outcomes from teledermatology. Furthermore, it is not intended to be used instead of a face-to-face appointment with a dermatologist.

Keywords: teledermatology, online dermatology consultation, dermatology, dermatologist

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Authors: A. P. Joshi, H. V. Warrior, J. P. Panda

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This paper is a continuation of the work carried out by various turbulence modelers in Oceanography on the topic of oceanic turbulent mixing. It evaluates the evolution of ocean water temperature and salinity by the appropriate modeling of turbulent mixing utilizing proper prescription of eddy viscosity. Many modelers in past have suggested including terms like shear, buoyancy and vorticity to be the parameters that decide the slow pressure strain correlation. We add to it the fact that dissipation anisotropy also modifies the correlation through eddy viscosity parameterization. This recalibrates the established correlation constants slightly and gives improved results. This anisotropization of dissipation implies that the critical Richardson’s number increases much beyond unity (to 1.66) to accommodate enhanced mixing, as is seen in reality. The model is run for a couple of test cases in the General Ocean Turbulence Model (GOTM) and the results are presented here.

Keywords: Anisotropy, GOTM, pressure-strain correlation, Richardson critical number

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Authors: Saja M. Nabat Al-Ajrash, Charles Browning, Rose Eckerle, Li Cao, Robyn L. Bradford, Donald Klosterman

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An additive manufacturing process and subsequent pyrolysis cycle were used to fabricate SiC matrix/carbon fiber hybrid composites. The matrix was fabricated using a mixture of preceramic polymer and acrylate monomers, while polyacrylonitrile (PAN) precursor was used to fabricate fibers via electrospinning. The precursor matrix and reinforcing fibers at 0, 2, 5, or 10 wt% were printed using digital light processing, and both were simultaneously pyrolyzed to yield the final ceramic matrix composite structure. After pyrolysis, XRD and SEAD analysis proved the existence of SiC nanocrystals and turbostratic carbon structure in the matrix, while the reinforcement phase was shown to have a turbostratic carbon structure similar to commercial carbon fibers. Thermogravimetric analysis (TGA) in the air up to 1400 °C was used to evaluate the oxidation resistance of this material. TGA results showed some weight loss due to oxidation of SiC and/or carbon up to about 900 °C, followed by weight gain to about 1200 °C due to the formation of a protective SiO2 layer. Although increasing carbon fiber content negatively impacted the total mass loss for the first heating cycle, exposure of the composite to second-run air revealed negligible weight chance. This is explained by SiO2 layer formation, which acts as a protective film that prevents oxygen diffusion. Oxidation of SiC and the formation of a glassy layer has been proven to protect the sample from further oxidation, as well as provide healing of surface cracks and defects, as revealed by SEM analysis.

Keywords: silicon carbide, carbon fibers, additive manufacturing, composite

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Authors: Sandy Elsayed, Aya Mohamed, Noha Nassar

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Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social deficits and repetitive behavior. Multiple studies suggest that oxidative stress and neuroinflammation are key factors in the etiology of ASD and often associated with worsening of ASD-related behaviors. Nuclear factor erythroid 2-related factor 2 (NRF-2) is a transcription factor that promotes expression of antioxidant response element genes in oxidative stress. In ASD subjects, decreased expression of NRF-2 in frontal cortex shifted the redox homeostasis towards oxidative stress, and resulted in inflammation evidenced by elevation of nuclear factor kappa B (NF-κB) transcriptional activity. Dimethyl fumarate (DMF) is a NRF-2 activator that is used in the treatment of psoriasis and multiple sclerosis. It participates in the transcriptional control of inflammatory factors via inhibition of NF-κB and its downstream targets. This study aimed to investigate the role of DMF in alleviating the cognitive impairments and behavior deficits associated with ASD through mitigation of oxidative stress and inflammation in prenatal valproic acid (VPA) rat model of autism. Methods: Pregnant female Wistar rats received a single intraperitoneal injection of VPA (600 mg/kg) to induce autistic-like-behavioral and neurobiological alterations in their offspring. Chronic oral gavage of DMF (150mg/kg/day) started from postnatal day (PND) 24 till PND62 (39 days). Prenatal VPA exposure elicited autistic behaviors including decreased social interaction and stereotyped behavior. Social interaction was evaluated using three-chamber sociability test and calculation of sociability index (SI), while stereotyped repetitive behavior and anxiety associated with ASD were assessed using marble burying test (MBT). Biochemical analyses were done on prefrontal cortex homogenates including NRF-2, and NF-κB expression. Moreover, inducible nitric oxide synthase (iNOS) gene expression and tumor necrosis factor (TNF-) protein expression were evaluated as markers of inflammation. Results: Prenatal VPA elicited decreased social interaction shown by decreased SI compared to control group (p < 0.001) and DMF enhanced SI (p < 0.05). In MBT, prenatal injection of VPA manifested stereotyped behavior and enhanced number of buried marbles compared to control (p < 0.05) and DMF reduced the anxiety-related behavior in rats exhibiting ASD-like behaviors (p < 0.05). In prefrontal cortex, NRF-2 expression was downregulated in prenatal VPA model (p < 0.0001) and DMF reversed this effect (p < 0.0001). The inflammatory transcription factor NF-κB was elevated in prenatal VPA model (p < 0.0001) and reduced (p < 0.0001) upon NRF-2 activation by DMF. Prenatal VPA expressed higher levels of proinflammatory cytokine TNF- compared to control group (p < 0.0001) and DMF reduced it (p < 0.0001). Finally, the gene expression of iNOS was downregulated upon NRF-2 activation by DMF (p < 0.01). Conclusion: This study proposes that DMF is a potential agent that can be used to ameliorate autistic-like-changes through NRF-2 activation along with NF-κB downregulation and therefore, it is a promising novel therapy for ASD.

Keywords: autism spectrum disorders, dimethyl fumarate, neuroinflammation, NRF-2

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Authors: Talebi Aliasghar, Ebrahimpour Komeleh Hooman, Maghsoudi Ali Akbar

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In reinforced concrete (RC) structures, beam-column connection region has a considerable effect on the behavior of structures. Using fiber reinforcement polymer (FRP) for the strengthening of connections in RC structures can be one of the solutions to retrofitting this zone which result in the enhanced behavior of structure. In this paper, these changes in behavior by using FRP for high strength concrete beam-column connection have been studied by finite element modeling. The concrete damage plasticity (CDP) model has been used to analyze the RC. The results illustrated a considerable development in load-bearing capacity but also a noticeable reduction in ductility. The study also assesses these qualities for several modes of strengthening and suggests the most effective mode of strengthening. Using FRP in flexural zone and FRP with 45-degree oriented fibers in shear zone of joint showed the most significant change in behavior.

Keywords: HSC, beam-column connection, Fiber Reinforcement Polymer, FRP, Finite Element Modeling, FEM

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Authors: A. Arya, R. Laha, V. R. Dantham

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We report the enhancement of Raman scattering signal by one order of magnitude using photonic nanojet (PNJ) of a lollipop shaped dielectric microstructure (LSDM) fabricated by a pulsed CO₂ laser. Here, the PNJ is generated by illuminating sphere portion of the LSDM with non-resonant laser. Unlike the surface enhanced Raman scattering (SERS) technique, this technique is simple, and the obtained results are highly reproducible. In addition, an efficient technique is proposed to enhance the SERS signal with the help of high quality factor optical resonance (whispering gallery mode) of a LSDM. From the theoretical simulations, it has been found that at least an order of magnitude enhancement in the SERS signal could be achieved easily using the proposed technique. We strongly believe that this report will enable the research community for improving the Raman scattering signals.

Keywords: localized surface plasmons, photonic nanojet, SERS, whispering gallery mode

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Authors: Ramanjit Kaur, N. C. Kothiyal

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The present study compares the improved mechanical strength of cement mortar nanocomposites (CNCs) using polycarboxylate superplasticizer (PCE-SP) stabilized graphene oxide or functionalized carbon nanotubes (SP-GO and SP-FCNT) as reinforcing agents. So, in the present study, GO, and FCNT have been sterically stabilized via superplasticizer. The obtained results have shown that a dosage of 0.02 wt% of SP-GO and 0.08 wt% of SP-FCNTs showed an improvement in compressive strength by 23.2% and 16.5%, respectively. On the other hand, incorporation of 0.04% SP-GO and SP-FCNT resulted in an enhanced split tensile strength of 38.5% and 35.8%, respectively, as compared to the control sample at 90 days of curing. Mercury Intrusion Porosimetry (MIP) observations presented a decline in the porosity of 0.02% SP-GO-CNCs and 0.08% SP-FCNT-CNCs by 25% and 31% in comparison to the control sample. The improved hydration of CNCs contributing to the enhancement of physicomechanical strength has also been shown by SEM and XRD studies.

Keywords: graphene oxide, functionalized CNTs, steric stabilization, microstructure, crystalline behavior, pore structure refinement

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Authors: Stuart Bradley, Mathew Legg, Lilyan Panton

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Ultrasonic remote sensing is a useful tool for assessing the interior structure of complex targets. For these methods, significantly enhanced spatial resolution is obtained if the pulse is coded, for example using a linearly changing frequency during the pulse duration. Such pulses have a time-dependent spectral structure. Interpretation of the backscatter from targets is, therefore, complicated if the scattering is frequency-dependent. While analytic models are well established for steady sinusoidal excitations applied to simple shapes such as spheres, such models do not generally exist for temporally evolving excitations. Therefore, models are developed in the current paper for handling such signals so that the properties of the targets can be quantitatively evaluated while maintaining very high spatial resolution. Laboratory measurements on simple shapes are used to confirm the validity of the models.

Keywords: linear FM chirp, time-dependent acoustic scattering, ultrasonic remote sensing, ultrasonic scattering

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Authors: Melaku Takele Abate, Abbi Lemma Wodajo, Adula Bekele Hunde

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This study aimed at exploring mathematics teachers' reactions, learning, school leaders’ support, and use of the Lesson Study for Transformative Assessment (LSforTA) program ideas in practice. The LSforTA program was new, and therefore, a local and grounded approach was needed to examine teachers’ knowledge and skills acquired using LSforTA. So, a design-based research approach was selected to evaluate and refine the LSforTA approach. The results showed that LSforTA increased teachers' knowledge and use of different levels of mathematics assessment tasks. The program positively affected teachers' practices of transformative assessment and enhanced their knowledge and skills in assessing students in a transformative way. The paper concludes how the LSforTA procedures were adapted in response to this evaluation and provides suggestions for future development and research.

Keywords: classroom assessment, feedback practices, lesson study, mathematics, design-based research

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Authors: Rana I. Abdulghani, Amera I. Melhum

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With the abnormal growth of the usage of computers over networks and under the consideration or agreement of most of the computer security experts who said that the goal of building a secure system is never achieved effectively, all these points led to the design of the intrusion detection systems(IDS). This research adopts a comparison between two techniques for network intrusion detection, The first one used the (Particles Swarm Optimization) that fall within the field (Swarm Intelligence). In this Act, the algorithm Enhanced for the purpose of obtaining the minimum error rate by amending the cluster centers when better fitness function is found through the training stages. Results show that this modification gives more efficient exploration of the original algorithm. The second algorithm used a (Back propagation NN) algorithm. Finally a comparison between the results of two methods used were based on (NSL_KDD) data sets for the construction and evaluation of intrusion detection systems. This research is only interested in clustering the two categories (Normal and Abnormal) for the given connection records. Practices experiments result in intrude detection rate (99.183818%) for EPSO and intrude detection rate (69.446416%) for BP neural network.

Keywords: IDS, SI, BP, NSL_KDD, PSO

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Authors: Ankit Nagar, Dinesh Kumar Nauriyal, Sukhpal Singh

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This paper examines the key determinants of farmers’ access to agricultural extension services, sources of agricultural extension services preferred and accessed by the farmers. An ordered logistic regression model was used to analyse the data of the 360 sample households based on a primary survey conducted in western Uttar Pradesh, India. The study finds that farmers' decision to engage in the agricultural extension programme is significantly influenced by factors such as education level, gender, farming experience, social group, group membership, farm size, credit access, awareness about the extension scheme, farmers' perception, and distance from extension sources. The most intriguing finding of this study is that the progressive farmers, which have long been regarded as a major source of knowledge diffusion, are the most distrusted sources of information as they are suspected of withholding vital information from potential beneficiaries. The positive relationship between farm size and ‘Access’ underlines that the extension services should revisit their strategies for targeting more marginal and small farmers constituting over 85 percent of the agricultural households by incorporating their priorities in their outreach programs. The study suggests that marginal and small farmers' productive potential could still be greatly augmented by the appropriate technology, advisory services, guidance, and improved market access. Also, the perception of poor quality of the public extension services can be corrected by initiatives aimed at building up extension workers' capacity.

Keywords: agriculture, access, extension services, ordered logistic regression

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Authors: Deepika Biswas

Abstract:

Acinetobacter baumannii, a hospital-acquired pathogen, causes nosocomial infections including pneumonia, urinary tract infection, and secondary meningitis. Carbapenem is most effective antibiotics against it. Its increased resistance to carbapenems has been a rising global concern. Antibiotics such as carbapenem are unable to use on hospital setups to eradicate A. baumannii, hence different concentrations of disinfectants including phenol; sodium hypochlorite and ethanol are increasingly being used. The objective of the present study is to find an effective concentration of above disinfectants against carbapenem-resistant strain RS307 of A. baumannii. Growth kinetics of RS307 has been determined using UV-Vis spectrophotometer in the presence and absence of disinfectants in triplicate and its standard deviation has also been calculated which make the results more reliable. Differential growth curves were plotted, which showed the effective concentration among all the concentrations of phenol, sodium hypochlorite and ethanol. On disc diffusion assay, antimicrobial effect was observed by comparing all the concentrations of disinfectants to check its synergy with imipenem, most effective carbapenem. All the results collectively revealed that 0.5% phenol, 0.5% sodium hypochlorite, and 70% ethanol could preferably be used as disinfectant for hospital setup against the carbapenem-resistant strain of A. baumannii. SDS PAGE analysis showed differential expression in the protein profile of A. baumannii after treatment. The present study highlighted that few disinfectants even in low concentration had shown better antimicrobial activity hence may be recommended for regular use in the hospitals, which will be cost effective and less harmful.

Keywords: Acenatobacter bomunii, phenol, sodium hypoclirite, ethanol, carbapenem resistance, disinfectant

Procedia PDF Downloads 252

Authors: RuiJin Zhang, HengJiang Cai, JinSong Gui

Abstract:

It takes Patinopecten yessoensis larvae more than 20 days from spawning to settlement. Due to the natural environmental factors such as current, Patinopecten yessoensis larvae are transported to a distance more than hundreds of kilometers, leading to a high instability of their spatial and temporal distribution and great difficulties in the natural spat collection. Therefore predicting the distribution is of great significance to improve the operating efficiency of the collecting. Hydrodynamic model of Northern China Yellow Sea was established and the motions equations of physical oceanography and verified by the tidal harmonic constants and the measured data velocities of Dalian Bay. According to the passivity drift characteristics of the larvae, combined with the hydrodynamic model and the particle tracking model, the spatial and temporal distribution prediction model was established and the spatial and temporal distribution of the larvae under the influence of flow and wind were simulated. It can be concluded from the model results: ocean currents have greatest impacts on the passive drift path and diffusion of Patinopecten yessoensis larvae; the impact of wind is also important, which changed the direction and speed of the drift. Patinopecten yessoensis larvae were generated in the sea along Zhangzi Island and Guanglu-Dachangshan Island, but after two months, with the impact of wind and currents, the larvae appeared in the west of Dalian and the southern of Lvshun, and even in Bohai Bay. The model results are consistent with the relevant literature on qualitative analysis, and this conclusion explains where the larvae come from in the perspective of numerical simulation.

Keywords: numerical simulation, Patinopecten yessoensis larvae, predicting model, spatial and temporal distribution

Procedia PDF Downloads 300

Authors: V. V. Lakshmi, Y. V. S. Annapurna

Abstract:

Urinary tract infection (UTI) is one of the most common infectious diseases seen in the community. Susceptible individuals experience multiple episodes, and progress to acute pyelonephritis or uro-sepsis or develop asymptomatic bacteriuria (ABU). Ability to cause extraintestinal infections depends on several virulence factors required for survival at extraintestinal sites. Presence of virulence phenotypes enhances the pathogenicity of these otherwise commensal organisms and thus augments its ability to cause extraintestinal infections, the most frequent in urinary tract infections(UTI). The present study focuses on detection of the virulence characters exhibited by the uropathogenic organism and most common factors exhibited in the local pathogens. A total of 700 isolates of E.coli and Klebsiella spp were included in the study.These were isolated from patients from local hospitals reported to be suffering with UTI over a period of three years. Isolation and identification was done based on Gram character and IMVIC reactions. Antibiotic sensitivity profile was carried out by disc diffusion method and multi drug resistant strains with MAR index of 0.7 were further selected. Virulence features examined included their ability to produce exopolysaccharides, protease- gelatinase production, hemolysin production, haemagglutination and hydrophobicity test. Exopolysaccharide production was most predominant virulence feature among the isolates when checked by congo red method. The biofilms production examined by microtitre plates using ELISA reader confirmed that this is the major factor contributing to virulencity of the pathogens followed by hemolysin production.

Keywords: Escherichia coli, Klebsiella spp, Uropathogens, virulence features

Procedia PDF Downloads 315