785 research outputs found

    A Quantum Key Distribution Network Through Single Mode Optical Fiber

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    Quantum key distribution (QKD) has been developed within the last decade that is provably secure against arbitrary computing power, and even against quantum computer attacks. Now there is a strong need of research to exploit this technology in the existing communication networks. In this paper we have presented various experimental results pertaining to QKD like Raw key rate and Quantum bit error rate (QBER). We found these results over 25 km single mode optical fiber. The experimental setup implemented the enhanced version of BB84 QKD protocol. Based upon the results obtained, we have presented a network design which can be implemented for the realization of large scale QKD networks. Furthermore, several new ideas are presented and discussed to integrate the QKD technique in the classical communication networks.Comment: This paper has been submitted to the 2006 International Symposium on Collaborative Technologies and Systems (CTS 2006)May 14-17, 2006, Las Vegas, Nevada, US

    A Wedge-DCB Test Methodology to Characterise High Rate Mode-I Interlaminar Fracture Properties of Fibre Composites

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    A combined numerical-experimental methodology is presented to measure dynamic Mode-I fracture properties of fiber reinforced composites. A modified wedge-DCB test using a Split-Hopkinson Bar technique along with cohesive zone modelling is utilised for this purpose. Three different comparison metrics, namely, strain-displacement response, crack propagation history and crack opening history are employed in order to extract unique values for the cohesive fracture properties of the delaminating interface. More importantly, the complexity of dealing with the frictional effects between the wedge and the DCB specimen is effectively circumvented by utilising right acquisition techniques combined with an inverse numerical modelling procedure. The proposed methodology is applied to extract the high rate interlaminar fracture properties of carbon fiber reinforced epoxy composites and it is further shown that a high level of confidence in the calibrated data can be established by adopting the proposed methodology

    Solar Light Induced Photo Catalytic Properties of α-Fe2O3 Nanoparticles for Degradation of Methylene Blue Dye

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    The present work describes α-Fe2O3 nanoparticles are prepared by chemical displacement method using CTAB as a stabilizing agent. Glutaric acid as fuel and metal salt like ferrous sulphate was used in synthesis. The structural, morphological, metal percentage and optical properties of as synthesized nanoparticles are investigated by using x-ray diffraction (XRD), UV-Visible Spectra; field emission gun Scanning electron microscopy (FEG-SEM) with EDS, Fourier transforms infrared spectroscopy (FTIR), High-resolution Transmission electron microscopy (HR-TEM) and Photoluminescence Spectroscopy (PL). The photocatalytic degradation of Methylene Blue dye was measured by visible absorption spectroscopy. To obtain the most favorable conditions for degradation of MB dye, the effect of various experimental parameters, i.e., pH, amount of nanoparticles, concentration of dye and light intensity on the rate of reaction was studied. A tentative mechanism for the photocatalytic degradation of Methylene Blue was proposed. Photocatalytic degradation of Methylene Blue dye followed pseudo first-order kinetics. It was found that the dye degradation gave the best results at a pH of 6.0, and using a 70 mW•cm–2 light intensity with 0.3 g of α-Fe2O3 nanoparticles. At room temperature, the photocatalytic degradation of Methylene Blue dye was observed about 92.3%

    Technological Developments and the Role of L2 Motivation in University English Language Teaching Education

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    The 21st century is the era of technology and digitalization in teaching and learning dynamics., The present study explores the function of L2 motivation in university-based English language teaching (ELT) education. It also seeks to comprehend how technological developments are changing L2 motivation and examines teachers coping mechanisms in this changing educational environment. This study employs a qualitative research approach to explore the university teachers choices of technology instruments and pedagogical choices for enhancing students’ L2 motivation. Thus, the study uses semi-structured interviews to collect data from the 15 university teachers, (8 from Pakistan and 7 from Russia). Moreover, the secondary aim of the study is to comprehend the variables influencing L2 teacher motivation, and pedagogical approaches. This study adds to the body of information on language teaching by emphasizing the necessity for university teachers to adapt to changes in L2 motivation by utilizing technology, developing cutting-edge resources, and creating motivating learning settings

    Multi-category Bangla News Classification using Machine Learning Classifiers and Multi-layer Dense Neural Network

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    Online and offline newspaper articles have become an integral phenomenon to our society. News articles have a significant impact on our personal and social activities but picking a piece of an appropriate news article is a challenging task for users from the ocean of sources. Recommending the appropriate news category helps find desired articles for the readers but categorizing news article manually is laborious, sluggish and expensive. Moreover, it gets more difficult when considering a resource-insufficient language like Bengali which is the fourth most spoken language of the world. However, very few approaches have been proposed for categorizing Bangla news articles where few machine learning algorithms were applied with limited resources. In this paper, we accentuate multiple machine learning approaches including a neural network to categorize Bangla news articles for two different datasets. News articles have been collected from the popular Bengali newspaper Prothom Alo to build Dataset I and dataset II has been gathered from the famous machine learning competition platform Kaggle. We develop a modified stop-word set and apply it in the preprocessing stage which leads to significant improvement in the performance. Our result shows that the Multi-layer Neural network, Naïve Bayes and support vector machine provide better performance. Accuracy of 94.99%, 94.60%, 95.50% has been achieved for SVM, Logistic regression and Multi-layer dense neural network, respectively

    Understanding the Complexity of Motivational Orientations towards Learning English among Pakistani Female University Students

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    The present study goal is to investigate female university students’ motivation toward learning English as Second Language (ESL) studying at the University of Sindh, Pakistan. Two main objectives of the study were to evaluate the motivational orientation of the female learners in terms of integrativeness or instrumentality. Second, to study the factors that affect the learners motivation towards learning English. A mixed-method approach was employed with descriptive and inferential statistics were performed on the data to evaluate the data. A number of 158 female students from both the Science and Arts faculties at the English and Chemistry departments filled the structured questionnaire. Additionally, to gain a deeper understanding of the researched phenomenon, the semi-structured interviews were conducted with 20 students. The findings revealed a complex portrait of the target population, with the most prominent motivational factors being integrative motive, classroom environment, and instrumental motive. Besides, the influence of teachers was found to induce behavioral changes, while gender did not appear to significantly impact the learning process

    Identification of major factors influencing ELISpot-based monitoring of cellular responses to antigens from mycobacterium tuberculosis

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    A number of different interferon-c ELISpot protocols are in use in laboratories studying antigen-specific immune responses. It is therefore unclear how results from different assays compare, and what factors most significantly influence assay outcome. One such difference is that some laboratories use a short in vitro stimulation period of cells before they are transferred to the ELISpot plate; this is commonly done in the case of frozen cells, in order to enhance assay sensitivity. Other differences that may be significant include antibody coating of plates, the use of media with or without serum, the serum source and the number of cells added to the wells. The aim of this paper was to identify which components of the different ELISpot protocols influenced assay sensitivity and inter-laboratory variation. Four laboratories provided protocols for quantifying numbers of interferon-c spot forming cells in human peripheral blood mononuclear cells stimulated with Mycobacterium tuberculosis derived antigens. The differences in the protocols were compared directly. We found that several sources of variation in assay protocols can be eliminated, for example by avoiding serum supplementation and using AIM-V serum free medium. In addition, the number of cells added to ELISpot wells should also be standardised. Importantly, delays in peripheral blood mononuclear cell processing before stimulation had a marked effect on the number of detectable spot forming cells; processing delay thus should be minimised as well as standardised. Finally, a pre-stimulation culture period improved the sensitivity of the assay, however this effect may be both antigen and donor dependent. In conclusion, small differences in ELISpot protocols in routine use can affect the results obtained and care should be given to conditions selected for use in a given study. A pre-stimulation step may improve the sensitivity of the assay, particularly when cells have been previously frozen

    Safety and immunogenicity of a new tuberculosis vaccine, MVA85A, in mycobacterium tuberculosis–infected individuals

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    Copyright © 2009 by the American Thoracic Society.Rationale: An effective new tuberculosis (TB) vaccine regimen must be safe in individuals with latent TB infection (LTBI) and is a priority for global health care. Objectives: To evaluate the safety and immunogenicity of a leading new TB vaccine, recombinant Modified Vaccinia Ankara expressing Antigen 85A (MVA85A) in individuals with LTBI. Methods: An open-label, phase I trial of MVA85A was performed in 12 subjects with LTBI recruited from TB contact clinics in Oxford and London or by poster advertisements in Oxford hospitals. Patients were assessed clinically and had blood samples drawn for immunological analysis over a 52-week period after vaccination with MVA85A. Thoracic computed tomography scans were performed at baseline and at 10 weeks after vaccination. Safety of MVA85A was assessed by clinical, radiological, and inflammatory markers. The immunogenicity of MVA85A was assessed by IFNγ and IL-2 ELISpot assays and FACS. Measurements and Main Results: MVA85A was safe in subjects with LTBI, with comparable adverse events to previous trials of MVA85A. There were no clinically significant changes in inflammatory markers or thoracic computed tomography scans after vaccination. MVA85A induced a strong antigen-specific IFN-γ and IL-2 response that was durable for 52 weeks. The magnitude of IFN-γ response was comparable to previous trials of MVA85A in bacillus Calmette-Guérin–vaccinated individuals. Antigen 85A–specific polyfunctional CD4+ T cells were detectable prior to vaccination with statistically significant increases in cell numbers after vaccination. Conclusions: MVA85A is safe and highly immunogenic in individuals with LTBI. These results will facilitate further trials in TB-endemic areas.Oxford Biomedical Research Centre, Wellcome Trust, and AFTBVAC

    Adsorption of Eriochrome Black-T dye by batch investigations using waste tea@Fe NPs as low-cost adsorbent

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    This work has examined the efficaciousness of iron nanoparticles made from tea waste extract in the elimination of Eriochrome black T (EBT) dye. Field emission gun scanning electron microscopy (FEG-SEM) with EDAX, High- resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and FTIR spectroscopy were used to evaluate the synthesized iron capped nanoparticles. Iron nanoparticles seemed amorphous, according to the X-ray diffraction patterns. The spherical form of the Fe NPs was discernibly shown by scanning electron microscopy. Particle size of Fe NPs is found to be in the 30–40 nm range using transmission electron microscopy (HR-TEM). Additionally, research was done on the deterioration of the Eriochrome black T pigment (EBT). It was investigated how several experimental factors, such as the amount of adsorbent, pH, dye concentration, and contact duration, affected the pace of reaction in order to determine the ideal conditions for dye degradation. There are pseudo-first-order kinetics involved in the adsorption of the dye Eriochrome black T (EBT). At a pH of 3, 50 ppm of Eriochrome Black T (EBT) dye concentration, and 0.60 g of adsorbent, the dye degradation was observed to exhibit optimized results. The highest dye elimination was accomplished by stirring for 90 minutes at a Room temperature

    Caesarean myomectomy in a patient with multiple maternal and fetal comorbidities: a rare interesting case report

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    Caesarean myomectomy has been traditionally discouraged due to the fear of complications like intractable haemorrhage, peripartum hysterectomy, and increased postoperative morbidity. Recently, a number of authors in their studies have shown that myomectomy during caesarean section does not increase the risk of haemorrhage or postoperative morbidity, if adequate haemostatic methods are used and done by skilled surgical hands. Caesarean myomectomy was performed in a case of elderly primigravida with 36-week gestation with chronic hypertension with polyhydramnios with anterior wall pedunculated fibroid of 8.6×7.2×8 cm and multiple small fibroids in the anterior wall, fundus and subserosal plane. Caesarean myomectomy is a safe and effective procedure in a tertiary care centre at hands of an experienced surgeon
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