Search results for: External aerodynamics

Authors: M. Brahim, I. Bahri, Y. Bernard

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Traveling Wave Ultrasonic Motor (TWUM) is a compact, precise, and silent actuator generating high torque at low speed without gears. Moreover, the TWUM has a high holding torque without supply, which makes this motor as an attractive solution for holding position of robotic arms. However, their nonlinear dynamics, and the presence of load-dependent dead zones often limit their use. Those issues can be overcome in closed loop with effective and precise controllers. In this paper, robust H-infinity (H∞) and discrete time RST position controllers are presented. The H∞ controller is designed in continuous time with additional weighting filters to ensure the robustness in the case of uncertain motor model and external disturbances. Robust RST controller based on the pole placement method is also designed and compared to the H∞. Simulink model of TWUM is used to validate the stability and the robustness of the two proposed controllers.

Keywords: Piezoelectric motors, position control, H∞, RST, stability criteria, robustness.

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Authors: Ali A. Ahmed, Mohammed I. Hussein

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The amounts of radioactivity in the igneous rocks have been investigated; samples were collected from the total of eight basalt rock types in the northeastern of Kurdistan region/Iraq. The activity concentration of 226Ra (238U) series, 228Ac (232Th) series, 40K and 137Cs were measured using Planar HPGe and NaI(Tl) detectors. Along the study area the radium equivalent activities Raeq in Bq/Kg of samples under investigation were found in the range of 22.16 to 77.31 Bq/Kg with an average value of 44.8 Bq/Kg, this value is much below the internationally accepted value of 370 Bq/Kg. To estimate the health effects of this natural radioactive composition, the average values of absorbed gamma dose rate D (55 nGyh-1), Indoor and outdoor annual effective dose rates Eied (0.11 mSvy-1) . and Eoed (0.03 mSvy-1), External hazard index Hex (0.138) and internal hazard index Hin(0.154), and representative level index Iγr (0.386) have been calculated and found to be lower than the worldwide average values.

Keywords: Absorbed dose, activity concentration, igneousrocks, HPGe, NaI(TI), Natural Radioactivity.

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Authors: Cândida M. Pereira, Amílcar L. Ramalho, Jorge A. Ambrósio

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In the numerical solution of the forward dynamics of a multibody system, the positions and velocities of the bodies in the system are obtained first. With the information of the system state variables at each time step, the internal and external forces acting on the system are obtained by appropriate contact force models if the continuous contact method is used instead of a discrete contact method. The local deformation of the bodies in contact, represented by penetration, is used to compute the contact force. The ability and suitability with current cylindrical contact force models to describe the contact between bodies with cylindrical geometries with particular focus on internal contacting geometries involving low clearances and high loads simultaneously is discussed in this paper. A comparative assessment of the performance of each model under analysis for different contact conditions, in particular for very different penetration and clearance values, is presented. It is demonstrated that some models represent a rough approximation to describe the conformal contact between cylindrical geometries because contact forces are underestimated.

Keywords: Clearance joints, Contact mechanics, Contact dynamics, Internal cylindrical contact, Multibody dynamics.

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Authors: R. Testoni, R. Levizzari, M. De Salve

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Radioactive waste management is fundamental to safeguard population and environment by radiological risks. Environmental assessment of a site, where nuclear activities are located, allows understanding the hydro geological system and the radionuclides transport in groundwater and subsoil. Use of dedicated software is the basis of transport phenomena investigation and for dynamic scenarios prediction; this permits to understand the evolution of accidental contamination events, but at the same time the potentiality of the software itself can be verified. The aim of this paper is to perform a numerical analysis by means of HYDRUS 1D code, so as to evaluate radionuclides transport in a nuclear site in Piedmont region (Italy). In particular, the behavior in vadose zone was investigated. An iterative assessment process was performed for risk assessment of radioactive contamination. The analysis therein developed considers the following aspects: i) hydro geological site characterization; ii) individuation of the main intrinsic and external site factors influencing water flow and radionuclides transport phenomena; iii) software potential for radionuclides leakage simulation purposes.

Keywords: HYDRUS 1D, radionuclides transport phenomena, site characterization.

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Authors: Haitham Assiri, Majed Eljazzar, Priyadarsi Nanda

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The world is gradually entering the fourth industrial revolution. E-Government services are scaling government operations across the globe. However, as promising as an e-Government system would be, it is also susceptible to malicious attacks if not properly secured. In our study, we found that in Saudi Arabia, the e-Government website, Yesser, is vulnerable to external attacks. Obviously, this can lead to a breach of data integrity and privacy. In this paper, a systematic literature review (SLR) was conducted to explore possible ways the Kingdom of Saudi Arabia can take necessary measures to strengthen its e-Government system using blockchain. Blockchain is one of the emerging technologies shaping the world through its applications in finance, elections, healthcare, etc. It secures systems and brings more transparency. A total of 28 papers were selected for this SLR, and 19 of the papers significantly showed that blockchain could enhance the security and privacy of Saudi’s e-Government system. Other papers also concluded that blockchain is effective, albeit with the integration of other technologies like IoT, AI and big data. These papers have been analyzed to sieve out the findings and set the stage for future research into the subject.

Keywords: blockchain, data integrity, e-Government, security threats

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Authors: Andrey A. Chernousov, Ben Y. B. Chan

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The thermal behavior of a large-scale, phase change material (PCM) enhanced building envelope system was studied in regard to the need for pre-fabricated construction in subtropical regions. The proposed large-scale envelope consists of a reinforced aluminum skin, insulation core, phase change material and reinforced gypsum board. The PCM impact on an energy efficiency of an enveloped room was resolved by validation of the EnergyPlus numerical scheme and optimization of a smart material location in the core. The PCM location was optimized by a minimization method of a cooling energy demand. It has been shown that there is good agreement between the test and simulation results. The optimal location of the PCM layer in Hong Kong summer conditions has been then recomputed for core thicknesses of 40, 60 and 80 mm. A non-dimensional value of the optimal PCM location was obtained to be same for all the studied cases and the considered external and internal conditions.

Keywords: Thermal performance, phase change material, energy efficiency, PCM optimization.

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Authors: A. Eštoková, M. Kovalčíková, A. Luptáková, A. Sičáková, M. Ondová

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Concrete durability as an important engineering property of concrete, determining the service life of concrete structures very significantly, can be threatened and even lost due to the interactions of concrete with external environment. Bio-corrosion process caused by presence and activities of microorganisms producing sulphuric acid is a special type of sulphate deterioration of concrete materials. The effects of sulphur-oxidizing bacteria Acidithiobacillus thiooxidans on various concrete samples, based on silica fume and zeolite, were investigated in laboratory during 180 days. A laboratory study was conducted to compare the performance of concrete samples in terms of the concrete deterioration influenced by the leaching of calcium and silicon compounds from the cement matrix. The changes in the elemental concentrations of calcium and silicon in both solid samples and liquid leachates were measured by using X – ray fluorescence method. Experimental studies confirmed the silica fume based concrete samples were found out to have the best performance in terms of both silicon and calcium ions leaching.

Keywords: Bio-corrosion, concrete, leaching, bacteria.

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Authors: Antonio Carlos Marques Alvim, Fernando Carvalho da Silva, Aquilino Senra Martinez

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For a quick and accurate calculation of spatial neutron distribution in nuclear power reactors 3D nodal codes are usually used aiming at solving the neutron diffusion equation for a given reactor core geometry and material composition. These codes use a second order polynomial to represent the transverse leakage term. In this work, a nodal method based on the well known nodal expansion method (NEM), developed at COPPE, making use of this polynomial expansion was modified to treat the transverse leakage term for the external surfaces of peripheral reflector nodes. The proposed method was implemented into a computational system which, besides solving the diffusion equation, also solves the burnup equations governing the gradual changes in material compositions of the core due to fuel depletion. Results confirm the effectiveness of this modified treatment of peripheral nodes for practical purposes in PWR reactors.

Keywords: Transverse leakage, nodal expansion method, power density, PWR reactors

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Authors: Drago Jakovcevic, Mihovil Andelinovic, Igor Husak

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The aim of this paper is to explore the economic circumstances in which the selective credit policy, the least used instrument of four types of instruments on disposal to central banks, should be used. The most significant example includes the use of selective credit policies in response to the emergence of the global financial crisis by the FED. Specifics of the potential use of selective credit policies as the instigator of economic growth in Croatia, a small open economy, are determined by high euroization of financial system, fixed exchange rate and long-term trend growth of external debt that is related to the need to maintain high levels of foreign reserves. In such conditions, the classic forms of selective credit policies are unsuitable for the introduction. Several alternative approaches to implement selective credit policies are examined in this paper. Also, thorough analysis of distribution of selective monetary policy loans among economic sectors in Croatia is conducted in order to minimize the risk of investing funds and maximize the return, in order to influence the GDP growth.

Keywords: Global crisis, Selective credit policy, Small open economy.

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Authors: Vijay Pal Singh, Yogesh Chandra Kotiyal

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Structures are a combination of various load carrying members which transfer the loads to the foundation from the superstructure safely. At the design stage, the loading of the structure is defined and appropriate material choices are made based upon their properties, mainly related to strength. The strength of materials kept on reducing with time because of many factors like environmental exposure and deformation caused by unpredictable external loads. Hence, to predict the strength of materials used in structures, various techniques are used. Among these techniques, Non-destructive techniques (NDT) are the one that can be used to predict the strength without damaging the structure. In the present study, the compressive strength of concrete has been predicted using Artificial Neural Network (ANN). The predicted strength was compared with the experimentally obtained actual compressive strength of concrete and equations were developed for different models. A good co-relation has been obtained between the predicted strength by these models and experimental values. Further, the co-relation has been developed using two NDT techniques for prediction of strength by regression analysis. It was found that the percentage error has been reduced between the predicted strength by using combined techniques in place of single techniques.

Keywords: Rebound, ultra-sonic pulse, penetration, ANN, NDT, regression.

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Authors: Lavish Ordia, A. Venugopal, Amit Agrawal, S. V. Prabhu

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The present study explores flow visualization experiments with various blunt shaped bluff bodies placed inside a circular pipe. The bodies mainly comprise of modifications of trapezoidal cylinder, most widely used in practical applications, such as vortex flowmeters. The present configuration possesses the feature of both internal and external flows with low aspect ratio. The vortex dynamics of bluff bodies in such configuration is seldom reported in the literature. Dye injection technique is employed to visualize the complex vortex formation mechanism behind the bluff bodies. The influence of orientation, slit and after body shape is studied in an attempt to obtain better understanding of the vortex formation mechanism. Various wake parameters like Strouhal number, vortex formation length and wake width are documented for these shapes. Vortex formation both with and without shear layer interaction is observed for most of the shapes.

Keywords: Flow visualization, Reynolds number, Strouhal number, vortex, vortex formation length, wake width.

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Authors: Salah I. Al-Mously, Marai M. Abousetta

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This paper investigates the impact of the hand-hold positions on both antenna performance and the specific absorption rate (SAR) induced in the user-s head. A cellular handset with external antenna operating at GSM-900 frequency is modeled and simulated using a finite difference time-domain (FDTD)-based platform SEMCAD-X. A specific anthropomorphic mannequin (SAM) is adopted to simulate the user-s head, whereas a semirealistic CAD-model of three-tissues is designed to simulate the user-s hand. The results show that in case of the handset in hand close to head at different positions; the antenna total efficiency gets reduced to (14.5% - 5.9%) at cheek-position and to (27.5% to 11.8%) at tilt-position. The peak averaged SAR1g values in head close to handset without hand, are 4.67 W/Kg and 2.66 W/Kg at cheek and tilt-position, respectively. Due to the presence of hand, the SAR1g in head gets reduced to (3.67-3.31 W/Kg) at cheek-position and to (1.84-1.64 W/Kg) at tilt-position, depending on the hand-hold position.

Keywords: FDTD, phantom, specific absorption rate (SAR), cellular handset exposure.

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Authors: V. Arabadzhi

Abstract:

We attempted investigate a boat model, based on the conversion of energy of surface wave into a sequence of unidirectional pulses of jet spurts, in other words - model of the boat, which is thrusting by the waves field on water surface. These pulses are forming some average reactive stream from the output nozzle on the stern of boat. The suggested model provides the conversion of its oscillatory motions (both pitching and rolling) into a jet flow. This becomes possible due to special construction of the boat and due to several details, sensitive to the local wave field. The boat model presents the uniflow jet engine without slow conversions of mechanical energy into intermediate forms and without any external sources of energy (besides surface waves). Motion of boat is characterized by fast jerks and average onward velocity, which exceeds the velocities of liquid particles in the wave.

Keywords: Flat-bottomed boat, Underwater wing, Input and output nozzles, Wave thrust, Conversion of wave into a jet stream, Oscillatory motion and onward motion, Squid-like pump, Hatch-like pump, The thrust due to lifting float, The thrust due to radiation reaction.

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Authors: Gulsevim Yumuk Gunay, Suleyman Gokhan Gunay

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Corporate social responsibility (CSR) can be defined as the management of social, environmental, economical and ethical concepts and firms sensivities to the expectations of the social stakeholders. CSR is seen as an important competitive advantage in the textile sector because this sector has an important impact on the environment and it is labor extensive. Textile sector has a strong advantage when compared with other sectors in Turkey due to its low labor costs and abundancy of raw materials. Turkey was a producer and an exporter of cotton, and an importer of fiber, clothes and dresses until 1950s. After 1950s, Turkey has begun to export fiber, ready-made clothes and become one of the most important textile producers in the world recently. CSR practices of the textile firms that are quoted in Istanbul Stock Exchange and these firms sensivities to their internal and external stakeholders and environment will be presented in this study.

Keywords: corporate social responsibility, Istanbul Stock Exchange, textile sector, Turkey

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Authors: Danielle Sandler dos Passos, Helder Coelho, Flávia Mori Sarti

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Analysing the world banking sector, we realize that traditional risk measurement methodologies no longer reflect the actual scenario with uncertainty and leave out events that can change the dynamics of markets. Considering this, regulators and financial institutions began to search more realistic models. The aim is to include external influences and interdependencies between agents, to describe and measure the operationalization of these complex systems and their risks in a more coherent and credible way. Within this context, X-Events are more frequent than assumed and, with uncertainties and constant changes, the concept of antifragility starts to gain great prominence in comparison to others methodologies of risk management. It is very useful to analyse whether a system succumbs (fragile), resists (robust) or gets benefits (antifragile) from disorder and stress. Thus, this work proposes the creation of the Banking Antifragility Index (BAI), which is based on the calculation of a triangular fuzzy number – to "quantify" qualitative criteria linked to antifragility.

Keywords: Complex adaptive systems, X-events, risk management, antifragility, banking antifragility index, triangular fuzzy number.

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Authors: Mountassar Maamoun, Mehdi Neggazi, Abdelhamid Meraghni, Daoud Berkani

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This paper presents a VLSI design approach of a highspeed and real-time 2-D Discrete Wavelet Transform computing. The proposed architecture, based on new and fast convolution approach, reduces the hardware complexity in addition to reduce the critical path to the multiplier delay. Furthermore, an advanced twodimensional (2-D) discrete wavelet transform (DWT) implementation, with an efficient memory area, is designed to produce one output in every clock cycle. As a result, a very highspeed is attained. The system is verified, using JPEG2000 coefficients filters, on Xilinx Virtex-II Field Programmable Gate Array (FPGA) device without accessing any external memory. The resulting computing rate is up to 270 M samples/s and the (9,7) 2-D wavelet filter uses only 18 kb of memory (16 kb of first-in-first-out memory) with 256×256 image size. In this way, the developed design requests reduced memory and provide very high-speed processing as well as high PSNR quality.

Keywords: Discrete Wavelet Transform (DWT), Fast Convolution, FPGA, VLSI.

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Authors: Michael Amberg, Dipl. Kfm. Johannes C. Panitz

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Compliance requires an effective communication within an enterprise as well as towards a company-s external environment. This requirement commences with the implementation of compliance within large scale compliance projects and still persists in the compliance reporting within standard operations. On the one hand the understanding of compliance necessities within the organization is promoted. On the other hand reduction of asymmetric information with compliance stakeholders is achieved. To reach this goal, a central reporting must provide a consolidated view of different compliance efforts- statuses. A concept which could be adapted for this purpose is the balanced scorecard by Kaplan / Norton. This concept has not been analyzed in detail concerning its adequacy for a holistic compliance reporting starting in compliance projects until later usage in regularly compliance operations. At first, this paper evaluates if a holistic compliance reporting can be designed by using the balanced scorecard concept. The current status of compliance reporting clearly shows that scorecards are generally accepted as a compliance reporting tool and are already used for corporate governance reporting. Additional specialized compliance IT - solutions exist in the market. After the scorecard-s adequacy is thoroughly examined and proofed, an example strategy map as the basis to derive a compliance balanced scorecard is defined. This definition answers the question on proceeding in designing a compliance reporting tool.

Keywords: Balanced Scorecard, Compliance, ComplianceReporting, Compliance Scorecard.

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Authors: Alaa-Aldin Abdul Rahim A. Al Athmay

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E-governance is an emerging and challenging initiative in developing countries. It is not only concerning the provision of services through the use ICT but rather entails building external interactions with citizen and businesses, enhancing democracy and trust of the political institutions of government. It embraces among other principles, openness, accountability and citizen engagement in public policy process. This study aims at finding users’ satisfaction with three chosen dimensions of e-governance, namely: openness, collaborative governance, and participation. These dimensions of e-governance are neither studied before in the context of Arab countries and nor explored earlier in relation to some demographics variables. A study of 900 users of e-government in United Arab Emirates (UAE) was undertaken to examine how gender, age, education, nationality, and employment affect their satisfaction with e-governance. Generally, satisfaction ratings vary significantly with these variables. However, the overall level of satisfaction with the three attributes was less favorable. Knowing the differences of  citizen’s perceptions towards e-governance services would help policymakers in the design of effective e-governance strategy.   

Keywords: E-governance, United Arab Emirates, Citizens' perceptions.

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Authors: Easa Ali Abbasi, Akbar Allahverdizadeh, Reza Jahangiri, Behnam Dadashzadeh

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Electrical current measurement is a suitable method for the performance determination of electrical devices. There are two contact and noncontact methods in this measuring process. Contact method has some disadvantages like having direct connection with wire which may endamage the system. Thus, in this paper, a bimorph piezoelectric cantilever beam which has a permanent magnet on its free end is used to measure electrical current in a noncontact way. In mathematical modeling, based on Galerkin method, the governing equation of the cantilever beam is solved, and the equation presenting the relation between applied force and beam’s output voltage is presented. Magnetic force resulting from current carrying wire is considered as the external excitation force of the system. The results are compared with other references in order to demonstrate the accuracy of the mathematical model. Finally, the effects of geometric parameters on the output voltage and natural frequency are presented.

Keywords: Cantilever beam, electrical current measurement, forced excitation, piezoelectric.

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Authors: Yongsei Lee, Hyunsu Park, Youngseob Yu, Heechan Yoo, Sungin Yoo

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A horizontal anaerobic digester was developed and tested in pilot scale for Korean food waste with high water contents (>80%). The hydrogen sulfide in the biogas was removed by a biological desulfurization equipment integrated in the horizontal digester. A mixer of the horizontal digester was designed to easily remove the sediment in the bottom and scum layers on surface in the digester. Experimental result for 120 days of operation of the pilot plant showed a high removal efficiency of 81.2% for organic substance and high stability during the whole operation period were acquired. Also food waste was treated at high organic loading rates over 4 kg•VS/m3∙day and a methane gas production rate of 0.62 m3/kg•VSremoved was accomplished. The biological desulfurization equipment inside the horizontal digester was proven to be an economic and effective method to reduce the biogas desulfurization cost by removing hydrogen sulfide more than 90% without external desulfurization equipments.

Keywords: Biogas, Biological desulfurization, Horizontal anaerobic digester, Korean food waste

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Authors: Atheel Hassan Alwash, Ahmad Zuhairi Abdullah, Norli Ismail

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Characteristics and sonocatalytic activity of zeolite Y catalysts loaded with TiO2 using impregnation and ion exchange methods for the degradation of amaranth dye were investigated. The Ion-exchange method was used to encapsulate the TiO2 into the internal pores of the zeolite while the incorporation of TiO2 mostly on the external surface of zeolite was carried out using the impregnation method. Different characterization techniques were used to elucidate the physicochemical properties of the produced catalysts. The framework of zeolite Y remained virtually unchanged after the encapsulation of TiO2 while the crystallinity of zeolite decreased significantly after the incorporation of 15 wt% of TiO2. The sonocatalytic activity was enhanced by TiO2 incorporation with maximum degradation efficiencies of 50% and 68% for the encapsulated titanium and titanium loaded onto the zeolite, respectively after 120min of reaction. Catalysts characteristics and sonocatalytic behaviors were significantly affected by the preparation method and the location of TiO2 introduced with zeolite structure. Behaviors in the sonocatalytic process were successfully correlated with the characteristics of the catalysts used.

Keywords: Sonocatalytic degradation, TiO2 loaded, ionexchange, impregnation, amaranth dye, process behavior.

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Authors: Ifedapo Francis Awolowo

Abstract:

The unrelenting series of embarrassing audit failures should stimulate a paradigm shift in accounting. And in this age of information revolution, there is need for a constant improvement on the products or services one offers to the market in order to be relevant. This study explores the perceptions of external auditors, forensic accountants and accounting academics on whether a paradigm shift to forensic accounting can reduce financial statement frauds. Through Neo-empiricism/inductive analytical approach, findings reveal that a paradigm shift to forensic accounting might be the right step in the right direction in order to increase the chances of fraud prevention and detection in the financial statement. This research has implication on accounting education on the need to incorporate forensic accounting into present day accounting curriculum. Accounting professional bodies, accounting standard setters and accounting firms all have roles to play in incorporating forensic accounting education into accounting curriculum. Particularly, there is need to alter the ISA 240 to make the prevention and detection of frauds the responsibilities of bot those charged with the management and governance of companies and statutory auditors.

Keywords: Financial statement fraud, forensic accounting, fraud prevention and detection, auditing, audit expectation gap, corporate governance.

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Authors: Yasar Bicer, Serif Yilmaz

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In present study, two kinds of thermal power plant ashes; one the fly ash and the other waste ash are mixed with adhesive tragacanth and cement to produce new composite materials. 48 new samples are produced by varying the percentages of the fly ash, waste ash, cement and tragacanth. The new samples are subjected to some tests to find out their properties such as thermal conductivity, compressive strength, tensile strength and sucking capability of water. It is found that; the thermal conductivity decreases with increasing amount of tragacanth in the mixture. The compressive, tensile strength increases when the rate of tragacanth is up to 1%, whilst as the amount of tragacanth increases up to 1.5%, the compressive, tensile strength decreases slightly. The rate of water absorption of samples was more than 30%. From this result, it is concluded that these materials can not be used as external plaster or internal plaster material that faces to water. They can be used in internal plaster unless touching water and they can be used as cover plaster under roof and riprap material in sandwich panels. It is also found that, these materials can be cut with saw, drilled with screw and painted with any kind of paint.

Keywords: Fly ash, tragacanth, cement, composite material.

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Authors: Sasitorn Chetanont, Benjaporn Yamjameung

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The objectives of this study are to increase tourism products and to develop family agro-tourism. The research methodology was to analyze internal and external situations according to MP-MF and the MC-STEPS principles.

The results of this study highlight following necessary improvements; extend the cycling routes, increase the number of bicycle rental shops, offer a recreation place for the elders, organize a space for the floating market products and increase tourism activities throughout the year. In ‘places or distribution channel’ we discuss the improvement of facilities, specifically the routes to facilitate elder visitors and visitors on wheelchairs and furthermore the arrangement of educational trips to relevant centers in the community. In ‘promotions’, we discuss the implementation of an “all inclusive package” were the agro-tourism program, health-conscious program and the elderly fun program converge.

Keywords: Marketing Planning Strategy, Agro-tourism, Bang Nam Phueng.

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Authors: Nariman O. Kandil, Ehab K. Abou-Elkheir, Amr M. Kotb

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Effective IT governance guarantees the strategic alignment of IT and business goals, risk mitigation control, and better IT and business performance. This study seeks to examine empirically the extent of IT governance implementation within the firms listed on the Egyptian Stock Exchange (EGX30) and its determinants. Accordingly, 18 semi-structured interviews, face to face, phone, and video-conferencing, using various tools (e.g., WebEx, Zoom, and Microsoft Teams) were undertaken at the interviewees’ offices in Egypt between the end of November 2019 and the end of August 2020. Results suggest that there are variances in the extent of IT Governance (ITG) implementation within the firms listed on the EGX30, mainly caused by the industry type and internal and external triggers. The results also suggest that the organization size, the type of auditor, the criticality of the industry, the effective processes & key performance indicators (KPIs), and the information intensity expertise of the chief information officers (CIOs) have a significant impact on ITG implementation within the firms.

Keywords: Effective IT governance, Egyptian Market, information security, risk controls.

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Authors: Teryima Oralu, Babatunde Kasim Oladele

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This paper looks at the management and funding of education in Nigeria. The concept of management and administration has been concisely defined. Also the historical background of educational management in Nigeria has been discussed alongside the management of primary education, secondary education and tertiary education in Nigeria. Furthermore, the funding of education has also been concisely discussed in this paper alongside the various sources of funds available to education in Nigeria. The sources include government grant, school fees, external aids, school revenue yielding businesses and so on. The budgetary allocation of Nigeria to education from 1999 to 2013 was also highlighted in this in paper and it was discovered that the lowest allocation was in 1999 with 4.46% while the highest allocation was in 2006 with 10.43%. It is also of note that, Nigeria is still yet to meet the recommendation of UNESCO of 26% budgetary allocation to education by developing countries. Recommendations have been drawn that the government should increase budgetary allocation to this sector in a consistent manner because of its importance to the national economy, hoping that with proper monitoring of fund, it would contribute more significantly to the development of the country. An effective utilization of such funds is also advocated for greater achievements. All organs of the government should exhibit good corporate governance and transparency and so on.

Keywords: Education, funding, management, Nigeria.

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Authors: Ashish Payal, C. S. Rai, B. V. R. Reddy

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With the increasing use and application of Wireless Sensor Networks (WSN), need has arisen to explore them in more effective and efficient manner. An important area which can bring efficiency to WSNs is the localization process, which refers to the estimation of the position of wireless sensor nodes in an ad hoc network setting, in reference to a coordinate system that may be internal or external to the network. In this paper, we have done comparison and analysed Sigmoidal Feedforward Artificial Neural Networks (SFFANNs) and Radial Basis Function (RBF) networks for developing localization framework in WSNs. The presented work utilizes the Received Signal Strength Indicator (RSSI), measured by static node on 100 x 100 m² grid from three anchor nodes. The comprehensive evaluation of these approaches is done using MATLAB software. The simulation results effectively demonstrate that FFANNs based sensor motes will show better localization accuracy as compared to RBF.

Keywords: Localization, wireless sensor networks, artificial neural network, radial basis function, multi-layer perceptron, backpropagation, RSSI.

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Authors: Dib Djalel, Haddouche Ali, Chellali Benachiba

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When a lightning strike falls near an overhead power line, the intense electromagnetic field radiated by the current of the lightning return stroke coupled with power lines and there induced transient overvoltages, which can cause a back-flashover in electrical network. The indirect lightning represents a major danger owing to the fact that it is more frequent than that which results from the direct strikes. In this paper we present an analysis of the electromagnetic coupling between an external electromagnetic field generated by the lightning and an electrical overhead lines, so we give an important and original contribution: We are based on our experimental measurements which we carried in the high voltage laboratories of EPFL in Switzerland during the last trimester of 2005, on the recent works of other authors and with our mathematical improvement a new particular analytical expression of the electromagnetic field generated by the lightning return stroke was developed and presented in this paper. The results obtained by this new electromagnetic field formulation were compared with experimental results and give a reasonable approach.

Keywords: Lightning, overhead lines, electromagneticcoupling, return stroke, models, induced overvoltages.

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Authors: H. Paredes Gutiérrez, S. T. Pérez-Merchancano

Abstract:

Motivated by recent experimental and theoretical developments, we investigate the influence of embedded quantum dot (EQD) of different geometries (lens, ring and pyramidal) in a double barrier heterostructure (DBH). We work with a general theory of quantum transport that accounts the tight-binding model for the spin dependent resonant tunneling in a semiconductor nanostructure, and Rashba spin orbital to study the spin orbit coupling. In this context, we use the second quantization theory for Rashba effect and the standard Green functions method. We calculate the current density as a function of the voltage without and in the presence of quantum dots. In the second case, we considered the size and shape of the quantum dot, and in the two cases, we worked considering the spin polarization affected by external electric fields. We found that the EQD generates significant changes in current when we consider different morphologies of EQD, as those described above. The first thing shown is that the current decreases significantly, such as the geometry of EQD is changed, prevailing the geometrical confinement. Likewise, we see that the current density decreases when the voltage is increased, showing that the quantum system studied here is more efficient when the morphology of the quantum dot changes.

Keywords: Quantum semiconductors, nanostructures, quantum dots, spin polarization.

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Authors: H. Elomari, M. Fallah, A. Elmousadik

Abstract:

This work was conducted in the Souss region, known by severe water scarcity and a high agricultural activity dominated by the citrus (representing 40% of the area of Morocco's citrus). The objective of this work is to diagnose the current situation of the water efficiency in citrus irrigation and analyze the impact of various production factors on water productivity and its sustainability in the context of climate change. A field survey was conducted on 65 farms with areas varying from 0.5 to 350 ha. The stratification method was adopted as a sampling frame. Initial result indicates that the use of water shows a huge shortfall, since 31% of farms in the region are still using the surface irrigation system and 67% of farms are still using only the experience of the manager to control and adjust irrigation. The assessment of water productivity showed a value of 1.2 kg/m³ for surface irrigation and 3.8 kg/m³ for drip irrigation. The use of tools for control and adjustment of irrigation increases the water productivity of drip irrigation by 25%. The availability of the technical staff (internal or external) allows an increase in productivity of 172.4% compared to farms without technical advice.

Keywords: Citrus, irrigation efficiency, water productivity, drip irrigation.

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