33,248 research outputs found

    People’s perception on agricultural vulnerabilities to climate change and SLR in Bangladesh: adaptation strategies and explanatory variables

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    The objective of this research is to evaluate people’s perception on vulnerabilities of agriculture and to explore effective adaptation options with identifying the underlying demographic, socio-economic and other relevant variables that influence the adaptation strategies in the sea level rise (SLR) hazard induced coastal areas of Bangladesh. The study finds that climate change and induced SLR are emerging threats to coastal agriculture of Bangladesh; hence, farmers are applying different adaptation strategies to reduce the vulnerabilities of coastal agriculture. Selection of effective adaptation strategies to vulnerabilities of agriculture depends not only on the magnitude, intensity and the impacts of climate change and SLR, but also perceptions and types of farmer, land, educational level, indigenous knowledge about adaptation, locational advantages, external support, community awareness and sharing of different effective mechanisms among the farmers. Effective adaptation strategies with high perceptions have significant influence to reduce the vulnerabilities of agriculture considering the adverse impacts of climate change and SLR. In time of extreme climatic hazards when a great loss in agriculture hamper the coastal agrobased economy, different effective indigenous local adaptation strategies through farmer awareness and community co-operation become vital for minimizing the impact of climatic hazards and reducing the vulnerabilities of coastal agriculture.Int. J. Agril. Res. Innov. & Tech. 8 (1): 70-78, June, 201

    Accretion Disks Around Black Holes: Twenty Five Years Later

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    We study the progress of the theory of accretion disks around black holes in last twenty five years and explain why advective disks are the best bet in explaining varied stationary and non-stationary observations from black hole candidates. We show also that the recently proposed advection dominated flows are incorrect.Comment: 30 Latex pages including figures. Kluwer Style files included. Appearing in `Observational Evidence for Black Holes in the Universe', ed. Sandip K. Chakrabarti, Kluwer Academic Publishers (DORDRECHT: Holland

    On suitable codes for frame synchronisation in packet radio LANs

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    Proactivity Toward Workplace Safety Improvement: An Investigation of Its Motivational Drivers and Organizational Outcomes

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    Initiating a safety oriented change - or safety initiative - is conceptually distinct from other forms of safety participation and safety citizenship behaviour, yet little attention has been given to its performance outcomes or its motivational antecedents. An initial study with a sample composed of middle managers (N = 86) showed that safety initiative predicted objective improvement actions six months later, whereas, showing differential validity, safety compliance predicted the implementation of monitoring actions. Two subsequent studies focused on motivational antecedents. First, using a sample of team leaders (N = 295), we tested a higher-order structure of proactive motivation that incorporates three domains: “can do”, “reason to” and future orientation. Second, in a longitudinal study of chemical work operators (N = 188), after checking for the influence of potential confounds (past behaviours; accidents experience; perceived risk), we showed that safety initiative was predicted only by proactive motivation. Instead, safety compliance was found to be associated with affective commitment and scrupulousness, whereas safety helping was found to be associated with affective commitment. Self-reported behaviours were validated against rater assessments. This study supports the importance of distinguishing safety initiative from other safety behaviours, indicating how to create an organizational context supporting a proactive management of workplace safety

    A Novel Blended State Estimated Adaptive Controller for Voltage and Current Control of Microgrid against Unknown Noise

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    © 2013 IEEE. In this study, a novel blended state estimated adaptive controller is designed for voltage and current control of microgrid against unknown noise. The core feature of the microgrid (MG) is its ability to integrate more than one distributed energy resource into the main grid. The state of a microgrid may deteriorate due to many reasons, for example malicious cyber-attacks, disturbances, packet losses, etc. Therefore, it is necessary to achieve the true state of the system to enhance the control requirement and automation of the microgrid. To achieve the true state of a microgrid, this study proposes the use of an algorithm based on the unscented kalman filter (UKF). The proposed state estimator technique is developed using an unscented-transformation and sigma-points measurement technique capable of minimizing the mean and covariance of a nonlinear cost function to estimate the true state of a single-phase, three-phase single-source and three-phase multi-source microgrid system. The advantage of the proposed estimator over using extended kalman filter (EKF) is investigated in simulations. The results demonstrate that the use of the UKF estimator produces a superior estimation of the system compared with the use of the EKF. An adaptive PID controller is also developed and used in system conjunction with the estimator to regulate its voltage and current against the number of loads. Deviation in load parameters hamper the function of the MG system. The performance of the developed controller is also evaluated against number of loads. Results indicate the controller provides a more stable and high-tracking performance with the inclusion of the UKF in the system

    Derivative chromosome 9 deletions in chronic myeloid leukaemia: Interpretation of atypical D-FISH pattern

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    Background/Aims: New molecular cytogenetic techniques are increasingly applied as a routine investigative tool in haematological malignancies, both at diagnosis and subsequent monitoring. This report describes the interpretation of atypical signal patterns encountered using BCR-ABL dual colour dual fusion fluorescence in situ hybridisation (D-FISH) translocation probes in chronic myeloid leukaemia (CML). Methods: Interphase FISH experiments were carried out using BCR-ABL D-FISH probes in 46 patients with CML at diagnosis and during subsequent disease monitoring. Atypical hybridisation signal patterns were characterised by molecular cytogenetic techniques and correlated with conventional karyotyping. Results: Two patients showed atypical interphase D-FISH patterns with one orange, one green, and one fusion (1O1G1F) signal. The presence of BCR-ABL gene fusion was documented by a dual colour single fusion (S-FISH) probe. The submicroscopic deletion of the ABL-BCR fusion gene on the derivative chromosome 9 in these cases was subsequently characterised by metaphase FISH on relocated G banded metaphases. Conclusions: Atypical interphase D-FISH patterns should not be interpreted in isolation and should be considered in conjunction with other cytogenetic or molecular genetic investigations.published_or_final_versio

    Disturbance observer based sliding mode control for a continuous stirred tank reactor (CSTR)

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    A continuous stirred tank reactor (CSTR) is typical of equipment found in the process control industry. The dynamics represent a wide class of second order nonlinear systems and thus as well as having specific industrial application, control of the CSTR is frequently used as a benchmark problem for application and testing of new control algorithms. Due to the high complexity of the CSTR system, the robust control design problem is challenging. This paper first establishes a mathematical model of the system. A disturbance observer is then designed to estimate the disturbance and a corresponding asymptotically stable sliding mode control is developed. Stability analysis is presented in terms of the Lyapunov method. Finally, based on experimental data, the proposed method is validated using simulation experiments

    Undoped gallium antimonide studied by positron annihilation spectroscopy

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    Positron lifetime spectroscopy has been used to study the vacancy type defects in undoped gallium antimonide. Temperature dependent positron trapping into the VGarelated defect having a characteristic lifetime of 310ps was observed in the as-grown sample. The lifetime data were well described by a model involving the thermal ionization (0/-) of the VGa-related defect and its ionization energy was found to be E(0/)=83meV. For the electron irradiated sample, the VGa-related defect with lifetime of 310ps that was found in the non-irradiated samples was also identified. Moreover, another lifetime component (280ps) was only observed in the electron irradiated sample but not in the non-irradiated sample. It was also attributed to the V Ga-related defect. The two identified VGa-related defects should have different microstructures because of their difference in characteristic lifetimes. The 280ps component remains thermally stable after the 500°C annealing while the 310ps component anneals at 300°C.published_or_final_versio

    Barriers to big data analytics in manufacturing supply chains: A case study from Bangladesh

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    © 2018 Elsevier Ltd Recently, big data (BD) has attracted researchers and practitioners due to its potential usefulness in decision-making processes. Big data analytics (BDA) is becoming increasingly popular among manufacturing companies as it helps gain insights and make decisions based on BD. However, there many barriers to the adoption of BDA in manufacturing supply chains. It is therefore necessary for manufacturing companies to identify and examine the nature of each barrier. Previous studies have mostly built conceptual frameworks for BDA in a given situation and have ignored examining the nature of the barriers to BDA. Due to the significance of both BD and BDA, this research aims to identify and examine the critical barriers to the adoption of BDA in manufacturing supply chains in the context of Bangladesh. This research explores the existing body of knowledge by examining these barriers using a Delphi-based analytic hierarchy process (AHP). Data were obtained from five Bangladeshi manufacturing companies. The findings of this research are as follows: (i) data-related barriers are most important, (ii) technology-related barriers are second, and (iii) the five most important components of these barriers are (a) lack of infrastructure, (b) complexity of data integration, (c) data privacy, (d) lack of availability of BDA tools and (e) high cost of investment. The findings can assist industrial managers to understand the actual nature of the barriers and potential benefits of using BDA and to make policy regarding BDA adoption in manufacturing supply chains. A sensitivity analysis was carried out to justify the robustness of the barrier rankings
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