181 research outputs found

    The Impact of Financial Risks on the Firms’ Performance

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    Firms are exposed to a variety of risks including credit risk, liquidity risk, foreign exchange risk, market risk and interest rate risk. An efficient risk management system is needed in time in order to control these risks. Managing risk is one of the basic tasks to be done, once it has been identified and known. The risk and return are directly related to each other, which means that increasing one will subsequently increase the other and vice versa. Financial risks have a great impact on firm’s performance. The study also assessed the current risk management practices of the firms and linked them with the firms’ financial performance. The findings confirm whether financial risks can be contained or managed in order for firms to achieve profit maximization for its shareholders. Keywords: Financial Risk; Firm’s Performance; Interest rate parity; Liquidity gap; Liquidity risk; Risk Management

    Seismic Microzonation of Central Khartoum, Sudan

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    A preliminary seismic microzonation of Central Khartoum, Sudan is proposed. Khartoum, the capital of Sudan, is located at the confluence of White and Blue Niles. The city is heavily populated. The Central Khartoum with its high rise buildings is the center of governmental and business activities and is located on strip adjacent to the Blue Nile. Geological and geotechnical data indicated that the subsoil conditions at Central Khartoum are characterized by alluvial deposits underlain by Nubian Sandstone below a depth of 20 m. The alluvial deposits locally known as Gezira formations, consist of clays grading into silt and sand with depth. Macro seismic zonation of Sudan and its vicinities, developed by the authors, gave the ground acceleration at the bed rock surface. The effect of alluvial deposits at Central Khartoum on propagation of seismic motion parameters to the ground surface is investigated in this study. Correlations are proposed for pertinent cyclic soil properties such as shear modulus, damping, and shear wave velocity. The classical shear beam model developed by Idriss and Seed is used to study the effect of local soil conditions on ground motion parameters. In absence of strong motion records, artificial time histories of ground motion parameters are used. Plots showing the time histories of ground motion parameters at the ground surface are obtained. The results indicated amplification of ground acceleration of up to 1.15. Because of the presence of saturated loose to medium dense sand at some locations within Central Khartoum, the risk of earthquake-induced liquefaction is evaluated. The susceplity of subsoils in Central Khartoum to liguefaction is evaluated probabilistically by modifying the classical method developed by Seed and Idriss. The risk of earthquake-induced liquefaction is computed by combining the seismic hazard and the conditional probability of liquefaction. The study showed that the risk of liquefaction is low

    A framework of a route optimization scheme for nested mobile network

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    Network mobility technology is now being accomplished with the foundation of NEMO (NEtwork MObility), developed by Internet Engineering Task Force (IETF). Although, it achieves optimal and continuous communication, it still suffers from some limitations, especially when the level of nesting increases. To overcome these drawbacks, this paper will present a route optimization framework for nested mobile network using hierarchical structure with Binding Update Tree (BUT). This framework should reduce packet overhead, handoff latency, packet transmission delay, and achieve optimal routing. At last, a comparison will be done with bi-directional tunneling used by NEMO Basic Support to evaluate the performance of the proposed framework

    Shear strengthening of reinforced concrete beams using externally-bonded aluminum alloy plates: An experimental study

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    Citation: Jamal A. Abdalla, Adi S. Abu-Obeidah, Rami A. Hawileh, Hayder A. Rasheed, Shear strengthening of reinforced concrete beams using externally-bonded aluminum alloy plates: An experimental study, Construction and Building Materials, Volume 128, 15 December 2016, Pages 24-37 http://dx.doi.org/10.1016/j.conbuildmat.2016.10.071Recently developed high strength aluminum alloys (AA) have desirable characteristics that make them attractive as externally bonded strengthening materials. This paper investigates the potential of using AA plates for shear strengthening of reinforced concrete (RC) beams. Five shear deficient RC beams were externally strengthened using AA plates with different orientations. It is observed that the shear capacity of the strengthened beams has increased in the range of 24%–89% compared to the un-strengthened beam. Shear capacity of the strengthened beams was also predicted using the ACI440, FIB14, TR55 and SMCFT design guidelines with the later one giving the most accurate predictions

    Geopolymer concrete incorporating recycled aggregates: A comprehensive review

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    Several industrial by-products are extensively used again as a supplementary cementitious material or aggregates in the interest to reduce environmental footprints in terms of energy depletion, pollution, waste disposition, resource depletion, and global warming related with conventional cement. A remarkable quantity of industrial scrap materials, primarily designated as construction and demolition waste from the construction industry, has transformed into crucial apprehension of governments. In the recent past, substantial explorations have been accomplished to appreciate the distinct characteristics of concrete, employing recycled aggregates from construction and demolition waste. Geopolymer composite is a new cementitious material, and it appears to be a potential replacement for conventional cement concrete. This paper summarises the previous research concerning the utilisation of recycled aggregate as a partial or complete supplants for conventional aggregates in geopolymer concrete. The influence of recycled aggregate addition on the fresh and hardened properties of geopolymer concrete is comprehensively reviewed in this paper. The studies suggest significant improvement in the workability on addition of recycled aggregates to geopolymer concrete. However, the addition results in increased water absorption and sorptivity

    Sustainable use of palm oil fuel ash as a supplementary cementitious material: A comprehensive review

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    Cement concrete has been popularly used as a construction material with an approximate annual consumption of 10 billion tons. Increase in urbanization and industrialization increased the demand of concrete materials at recent days. It has been estimated that the cement industry alone generates approximately 6–7% of the total CO2 emissions. These environmental concerns demand the use of alternative renewable and sustainable materials to produce green concrete. Meanwhile, a large amount of agricultural waste, especially palm oil waste is disposed into the open area and landfills, causing serious environmental problems. An estimated 12 million tons of palm oil fuel ash (POFA) is generated in the world per annum. To minimize the passive effects of concrete production using traditional Portland cement, it was recommended by many researchers to adopt the palm oil waste fall-outs as a supplementary cementitious material. It may be considered a suitable and reliable source for better solutions to magnify the sustainability of the construction industry. This paper reviews the potential utilization of POFA as an alternative cementitious material in concrete. The impact of POFA on the fresh, hardened and durability properties of concrete are deliberated, providing a brief of the current knowing about a suitable utilization of POFA as SCM to promote a sustainable environment in the construction industry. The grinding treatment of raw POFA particles significantly enhances the quality of POFA in terms of compressive strength, resistance against aggressive environments and assist in reducing the drying shrinkage of concrete, although there is a tendency to increase the water absorption and delay the hydration heat of cement mortar. The high quantity of SiO2 in POFA enables pozzolanic reaction and delays the setting times with the addition of CaO to produce further C–S–H gels. The utilization of POFA (20%), ultrafine POFA and nano POFA (30%) can produce high strength and durable concrete, proving to be a promising contribution towards the sustainability of the construction industry

    Automated reliability assessment for spectroscopic redshift measurements

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    We present a new approach to automate the spectroscopic redshift reliability assessment based on machine learning (ML) and characteristics of the redshift probability density function (PDF). We propose to rephrase the spectroscopic redshift estimation into a Bayesian framework, in order to incorporate all sources of information and uncertainties related to the redshift estimation process, and produce a redshift posterior PDF that will be the starting-point for ML algorithms to provide an automated assessment of a redshift reliability. As a use case, public data from the VIMOS VLT Deep Survey is exploited to present and test this new methodology. We first tried to reproduce the existing reliability flags using supervised classification to describe different types of redshift PDFs, but due to the subjective definition of these flags, soon opted for a new homogeneous partitioning of the data into distinct clusters via unsupervised classification. After assessing the accuracy of the new clusters via resubstitution and test predictions, unlabelled data from preliminary mock simulations for the Euclid space mission are projected into this mapping to predict their redshift reliability labels.Comment: Submitted on 02 June 2017 (v1). Revised on 08 September 2017 (v2). Latest version 28 September 2017 (this version v3
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