Search results for: Bottom core.

Authors: Amin Abedi, Naser Vosoughi, Mohammad Bagher Ghofrani

Abstract:

Double heterogeneity of randomly located pebbles in the core and Coated Fuel Particles (CFPs) in the pebbles are specific features in pebble bed reactors and usually, because of difficulty to model with MCNP code capabilities, are neglected. In this study, characteristics of HTR-10, Tsinghua University research reactor, are used and not only double heterogeneous but also truncated CFPs and Pebbles are considered.Firstly, 8335 CFPs are distributed randomly in a pebble and then the core of reactor is filled with those pebbles and graphite pebbles as moderator such that 57:43 ratio of fuel and moderator pebbles is established.Finally, four different core configurations are modeled. They are Simple Cubic (SC) structure with truncated pebbles,SC structure without truncated pebble, and Simple Hexagonal(SH) structure without truncated pebbles and SH structure with truncated pebbles. Results like effective multiplication factor (Keff), critical height,etc. are compared with available data.

Keywords: Double Heterogeneity, HTR-10, MCNP, Pebble Bed Reactor, Stochastic Geometry.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2855

Authors: M. Pasbani Khiavi, M. A. Ghorbani

Abstract:

This paper presents an analytical solution to get a reliable estimation of the hydrodynamic pressure on gravity dams induced by vertical component earthquake when solving the fluid and dam interaction problem. Presented analytical technique is presented for calculation of earthquake-induced hydrodynamic pressure in the reservoir of gravity dams allowing for water compressibility and wave absorption at the reservoir bottom. This new analytical solution can take into account the effect of bottom material on seismic response of gravity dams. It is concluded that because the vertical component of ground motion causes significant hydrodynamic forces in the horizontal direction on a vertical upstream face, responses to the vertical component of ground motion are of special importance in analysis of concrete gravity dams subjected to earthquakes.

Keywords: Dam, Reservoir, Analytical solution, Vertical component, Earthquake

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1750

Authors: Michael W. Markowitz

Abstract:

A central element of higher education today is the “core” or “general education” curriculum: that configuration of courses that often encompasses the essence of liberal arts education. Ensuring that such offerings reflect the mission and values of the institution is a challenge faced by most college and universities, often more than once. This paper presents an action model of program planning designed to structure the processes of developing, implementing and revising core curricula in a manner consistent with key institutional goals and objectives. Through presentation of a case study from a university in the United States, the elements of needs assessment, stakeholder investment and collaborative compromise are shown as key components of a planning strategy that can produce a general education program that is comprehensive, academically rigorous, assessable, and mission consistent. The paper concludes with recommendations for both the implementation and evaluation of such programs in practice.

Keywords: Academic assessment, academic program planning, curriculum development, general education reform.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1268

Authors: Seyed Abolhasan Naeini, Mohammad Hossein Zade

Abstract:

This article is an attempt to present a numerically study of the behaviour of an eccentrically loaded circular footing resting on sand to determine ‎its ultimate bearing capacity. A surface circular footing of diameter 12 cm (D) was used as ‎shallow foundation. For this purpose, three dimensional models consist of foundation, and medium sandy soil was modelled by ABAQUS software. Bearing capacity of footing was evaluated and the ‎effects of the load eccentricity on bearing capacity, its settlement, and modulus of subgrade reaction were studied. Three different values of load eccentricity with equal space from inside the core on the core boundary and outside the core boundary, which were respectively e=0.75, 1.5, and 2.25 cm, were considered. The results show that by increasing the load eccentricity, the ultimate load and the ‎modulus of subgrade reaction decreased.

Keywords: Circular foundation, eccentric loading, sand, modulus of subgrade reaction.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1647

Authors: A. Khebli, S. Aguib, Y. Kateb, L. Guenfoud, N. Chikh, M. Tourab, T. Djedid, W. Dilmi, A. Hadidi, H. Meglouli

Abstract:

Composite structures based on magnetorheological elastomers (MREs) are widely used in many industrial sectors, such as automotive, naval, railway, aeronautical, aerospace, and building industries because of their adjustable mechanical properties by an external stimulus. In this work, experimental tests and numerical simulations carried out have shown that the use of these new structures, developed from honeycomb core, and MRE with aluminum skins, make it possible to improve particularly the overall rigidity and to reduce the vibration amplitudes. The results found showed that these hybrid structures have a very good mechanical resistance due mainly to the honeycomb core, and a very good shock absorber due mainly to the core of the MRE. The elaborated composite structure is intended to be used in industrial sectors subject to great efforts and a high amplitude of vibration such as helicopter wings and air turbines.

Keywords: Hybrid sandwich structures, magnetorheological elastomer, honeycomb, 3-point bending, mechanical strength.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 180

Authors: Mubarak S. Mohsen, Rosni Abdullah, Yong M. Teo

Abstract:

Advances in processors architecture, such as multicore, increase the size of complexity of parallel computer systems. With multi-core architecture there are different parallel languages that can be used to run parallel programs. One of these languages is OpenMP which embedded in C/Cµ or FORTRAN. Because of this new architecture and the complexity, it is very important to evaluate the performance of OpenMP constructs, kernels, and application program on multi-core systems. Performance is the activity of collecting the information about the execution characteristics of a program. Performance tools consists of at least three interfacing software layers, including instrumentation, measurement, and analysis. The instrumentation layer defines the measured performance events. The measurement layer determines what performance event is actually captured and how it is measured by the tool. The analysis layer processes the performance data and summarizes it into a form that can be displayed in performance tools. In this paper, a number of OpenMP performance tools are surveyed, explaining how each is used to collect, analyse, and display data collection.

Keywords: Parallel performance tools, OpenMP, multi-core.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1922

Authors: Dr. N.H. Mvungi

Abstract:

The control of commutation of switched reluctance (SR) motor has nominally depended on a physical position detector. The physical rotor position sensor limits robustness and increases size and inertia of the SR drive system. The paper describes a method to overcome these limitations by using magnetization characteristics of the motor to indicate rotor and stator teeth overlap status. The method is using active current probing pulses of same magnitude that is used to simulate flux linkage in the winding being probed. A microprocessor is used for processing magnetization data to deduce rotor-stator teeth overlap status and hence rotor position. However, the back-of-core saturation and mutual coupling introduces overlap detection errors, hence that of commutation control. This paper presents the concept of the detection scheme and the effects of backof core saturation.

Keywords: Microprocessor control, rotor position, sensorless, switched reluctance.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1283

Authors: Stamatios A. Theocharis, George A. Tsihrintzis

Abstract:

One of the most important factors for the success of e-government is training and preparing the workforce of the public sector. As changes and innovation in the public sector progress at a very slow pace and more slowly than in the private sector, issues related to human resources require special care. This is because the workforce will eventually seize the opportunities of the technological solutions used in e-Government. Thus, the central administration should provide employees with continuous and focused training not only on new technologies but also on a wide range of subjects and also improve interdepartmental interaction.

To achieve all this, new methods and training tools need to be implemented in addition to assessment of the employees. In this spirit, we propose the development of an educational platform with user personalization features. We propose the development of this platform using Moodle as the basic tool. Incorporating a personalization mechanism is very important since different employees have different backgrounds, education levels, computer skills, or different capability to develop further. Key features of the proposed platform include, besides typical e-learning tools, communities organized in order to exchange experiences and knowledge, groups of users based on certain criteria, automatic evaluation of users and potential self-education and self-assessment. In its fully developed form, this platform can be part of a more comprehensive knowledge management system for the public sector.

Keywords: e-Government, civil employees education, education technologies.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1938

Authors: Sandu L., Topală F., Porojan S.

Abstract:

Restoration of endodontically treated teeth is a common problem in dentistry, related to the fractures occurring in such teeth and to concentration of forces little information regarding variation of basic preparation guidelines in stress distribution has been available. To date, there is still no agreement in the literature about which material or technique can optimally restore endodontically treated teeth. The aim of the present study was to evaluate the influence of the core height and restoration materials on corono-radicular restored upper first premolar. The first step of the study was to achieve 3D models in order to analyze teeth, dowel and core restorations and overlying full ceramic crowns. The FEM model was obtained by importing the solid model into ANSYS finite element analysis software. An occlusal load of 100 N was conducted, and stresses occurring in the restorations, and teeth structures were calculated. Numerical simulations provide a biomechanical explanation for stress distribution in prosthetic restored teeth. Within the limitations of the present study, it was found that the core height has no important influence on the stress generated in coronoradicular restored premolars. It can be drawn that the cervical regions of the teeth and restorations were subjected to the highest stress concentrations.

Keywords: 3D models, finite element analysis, dowel and core restoration, full ceramic crown, premolars, structural simulations.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2883

Authors: Amira A. A. Abdallah, Amir A. Beltagi

Abstract:

Background: Core stability training has recently attracted attention for improving muscle balance and optimizing performance in healthy and unhealthy individuals. Purpose: This study investigated the effect of beginner’s core stability exercises on trunk flexors’/extensors’ peak torque ratio and trunk flexors’ and extensors’ peak torques. Methods: Thirty five healthy individuals participated in the study. They were randomly assigned to two groups; experimental “group I, n=20” and control “group II, n=15”. Their mean age, weight and height were 20.7±2.4 vs. 20.3±0.61 years, 66.5±12.1 vs. 68.57±12.2 kg and 166.7±7.8 vs. 164.28 ±7.59 cm. for group I vs. group II. Data were collected using the Biodex Isokinetic system. The participants were tested twice; before and after a 6-week period during which group I performed a core stability training program. Results: The 2x2 Mixed Design ANOVA revealed that there were no significant differences (p>0.025) in the trunk flexors’/extensors’ peak torque ratio between the pre-test and post-test conditions for either group. Moreover, there were no significant differences (p>0.025) in the trunk flexion/extension ratios between both groups at either condition. However, the 2x2 Mixed Design MANOVA revealed significant increases (p<0.025) in the trunk flexors’ and extensors’ peak torques in the post-test condition compared with the pre-test in group I with no significant differences (p>0.025) in group II. Moreover, there was a significant increase (p<0.025) in the trunk flexors’ peak torque only in group I compared with group II in the post-test condition with no significant differences in the other conditions. Interpretation/Conclusion: The improvement in muscle performance indicated by the increase in the trunk flexors’ and extensors’ peak torques in the experimental group recommends including core stability training in the exercise programs that aim to improve muscle performance.

Keywords: Core Stability, Isokinetic, Trunk Muscles.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 3678

Authors: M. Shah Alam, Sarkar Rahat M. Anwar

Abstract:

The effect of thermally induced stress on the modal properties of highly elliptical core optical fibers is studied in this work using a finite element method. The stress analysis is carried out and anisotropic refractive index change is calculated using both the conventional plane strain approximation and the generalized plane strain approach. After considering the stress optical effect, the modal analysis of the fiber is performed to obtain the solutions of fundamental and higher order modes. The modal effective index, modal birefringence, group effective index, group birefringence, and dispersion of different modes of the fiber are presented. For propagation properties, it can be seen that the results depend much on the approach of stress analysis.

Keywords: Birefringence, dispersion, elliptical core fiber, optical mode analysis, stress-optic effect, stress analysis.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2290

Authors: Rui Yu, Huiqing Ying

Abstract:

To enhance installation security, a LNG storage in Rudong of Jiangsu province was adopted as a practical work, and it was analyzed by nonlinear finite element method to research overall and local stability performance, as well as the stress and deformation under the action of wind load and self-weight. Results indicate that deformation is tiny when steel mesh maintains as an overall ring, and stress caused by vertical bending moment and tension of bottom tie wire are also in the safe range. However, axial forces of lap reinforcement in adjacent steel mesh exceed the ultimate bearing capacity of tie wire. Hence, tie wires are ruptured; single mesh loses lateral connection and turns into monolithic status as the destruction of overall structure. Further more, monolithic steel mesh is led to collapse by the damage of bottom connection. So, in order to prevent connection failure and enhance installation security, the overlapping parts of steel mesh should be taken more reliable measures.

Keywords: low temperature steel mesh, installation stability, nonlinear finite element, tie wire.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1767

Authors: Djalal Hamed

Abstract:

The aim of this paper is to perform an analytic solution of steady state natural convection in a narrow rectangular channel between two vertical parallel MTR-type fuel plates, imposed under a cosine shape heat flux to determine the margin of the nuclear core power at which the natural convection cooling mode can ensure a safe core cooling, where the cladding temperature should not be reach the specific safety limits (90 °C). For this purpose, a simple computer program is developed to determine the principal parameter related to the nuclear core safety such as the temperature distribution in the fuel plate and in the coolant (light water) as a function of the reactor power. Our results are validated throughout a comparison against the results of another published work, which is considered like a reference of this study.

Keywords: Buoyancy force, friction force, friction factor, MTR-type fuel, natural convection, vertical heated rectangular channel.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 773

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

Abstract:

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.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2228

Authors: Y. Djouadi., F. Souam.

Abstract:

Most of the existing text mining approaches are proposed, keeping in mind, transaction databases model. Thus, the mined dataset is structured using just one concept: the “transaction", whereas the whole dataset is modeled using the “set" abstract type. In such cases, the structure of the whole dataset and the relationships among the transactions themselves are not modeled and consequently, not considered in the mining process. We believe that taking into account structure properties of hierarchically structured information (e.g. textual document, etc ...) in the mining process, can leads to best results. For this purpose, an hierarchical associations rule mining approach for textual documents is proposed in this paper and the classical set-oriented mining approach is reconsidered profits to a Direct Acyclic Graph (DAG) oriented approach. Natural languages processing techniques are used in order to obtain the DAG structure. Based on this graph model, an hierarchical bottom up algorithm is proposed. The main idea is that each node is mined with its parent node.

Keywords: Graph based association rules mining, Hierarchical document structure, Text mining.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2057

Authors: Ulrica Pettersson

Abstract:

Collection of information on incidents is regularly done through pre-printed incident report forms. These tend to be incomplete and frequently lack essential information. ne consequence is that reports with inadequate information, that do not fulfil analysts’ requirements, are transferred into the analysis process. To improve an incident reporting form, theory in design science, witness psychology and interview and questionnaire research has been used. Previously three experiments have been conducted to evaluate the form and shown significant improved results. The form has proved to capture knowledge, regardless of the incidents’ character or context. The aim in this paper is to describe how design science, in more detail a design hierarchy can be used to construct a collection form for improvements in safety science.

Keywords: Design science, data collection, form, incident report, safety science.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 834

Authors: M. Das, R. K. Saha, B. C. Meikap

Abstract:

Iron ore and coal are the two major important raw materials being used in Iron making industries. Usually ore fines containing around 5% Alumina are rejected due to higher proportion of alumina. Therefore, a technology or process which may reduce the alumina content by 2% by beneficiation process will be highly attractive . In addition fine coals with ash content is used nearly 12% is directly injected in blast furnace. Fast fluidization is a technology by using dry beneficiation of coal and iron ore can be done. During the fluidization process the iron ore band coal is fluidized at high velocity in the riser of a fast fluidized bed, the heavier and coarse particles is generally settled at the bottom in a dense zone of the riser while the finer and lighter particle are entrained to the top dilute zone and then via a cyclone is fed back to the bottom of the riser column. Most of the alumina and low ash fine size coals being lighter are expected to move up to the riser and by a natural beneficiation of ores is expected to take place in the riser. Therefore in this study an attempt has been made for dry beneficiation of iron ore and coal in a fluidized bed and its hydrodynamic characterization.

Keywords: beneficiation, fluidization, gas-solid fluidization, riser .

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2190

Authors: The Jaya Suteja, Stephany Tedjohartoko

Abstract:

Not all types of mobile phone are successful in entering the market because some types of the mobile phone have a negative perception of user. Therefore, it is important to understand the influence of mobile phone's characteristics in the local user perception. This research investigates the influence of QWERTY mobile phone's forms in the perception of Indonesian user. First, some alternatives of mobile phone-s form are developed based on a certain number of mobile phone's models. At the second stage, some word pairs as design attributes of the mobile phone are chosen to represent the user perception of mobile phone. At the final stage, a survey is conducted to investigate the influence of the developed form alternatives to the user perception. Based on the research, users perceive mobile phone's form with curved top and straight bottom shapes and mobile phone's form with slider and antenna as the most negative form. Meanwhile, mobile phone's form with curved top and bottom shapes and mobile phone-s form without slider and antenna are perceived by the user as the most positive form.

Keywords: Influence, mobile phone, form, user perception.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1370

Authors: S. A. H. Feghhi, Z. Gholamzadeh, Z. Alipoor, C. Tenreiro

Abstract:

Currently, thorium fuel has been especially noticed because of its proliferation resistance than long half-life alpha emitter minor actinides, breeding capability in fast and thermal neutron flux and mono-isotopic naturally abundant. In recent years, efficiency of minor actinide burning up in PWRs has been investigated. Hence, a minor actinide-contained thorium based fuel matrix can confront both proliferation resistance and nuclear waste depletion aims. In the present work, minor actinide depletion rate in a CANDU-type nuclear core modeled using MCNP code has been investigated. The obtained effects of minor actinide load as mixture of thorium fuel matrix on the core neutronics has been studied with comparing presence and non-presence of minor actinide component in the fuel matrix. Depletion rate of minor actinides in the MA-contained fuel has been calculated using different power loads. According to the obtained computational data, minor actinide loading in the modeled core results in more negative reactivity coefficients. The MA-contained fuel achieves less radial peaking factor in the modeled core. The obtained computational results showed 140 kg of 464 kg initial load of minor actinide has been depleted in during a 6-year burn up in 10 MW power.

Keywords: Minor actinide burning, CANDU-type reactor, MCNPX code, Neutronic parameters.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2148

Authors: J.C. Umavathi

Abstract:

The linear stability of nanofluid convection in a horizontal porous layer is examined theoretically when the walls of the porous layer are subjected to time-periodic temperature modulation. The model used for the nanofluid incorporates the effects of Brownian motion and thermopherosis, while the Darcy model is used for the porous medium. The analysis revels that for a typical nanofluid (with large Lewis number) the prime effect of the nanofluids is via a buoyancy effect coupled with the conservation of nanoparticles. The contribution of nanoparticles to the thermal energy equation being a second-order effect. It is found that the critical thermal Rayleigh number can be found reduced or decreased by a substantial amount, depending on whether the basic nanoparticle distribution is top-heavy or bottom-heavy. Oscillatory instability is possible in the case of a bottom-heavy nanoparticle distribution, phase angle and frequency of modulation.

Keywords: Brownian motion and thermophoresis, Porous medium, Nanofluid, Natural convection, Thermal modulation.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2170

Authors: Ghada Abdelmouez M., Fathy S. Helail, Abdellatif A. Elkouny

Abstract:

It is known that symmetric encryption algorithms are fast and easy to implement in hardware. Also elliptic curves have proved to be a good choice for building encryption system. Although most of the symmetric systems have been broken, we can create a hybrid system that has the same properties of the symmetric encryption systems and in the same time, it has the strength of elliptic curves in encryption. As DES algorithm is considered the core of all successive symmetric encryption systems, we modified DES using elliptic curves and built a new DES algorithm that is hard to be broken and will be the core for all other symmetric systems.

Keywords: DES, Elliptic Curves, hybrid system, symmetricencryption.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1737

Authors: Andreas L. Savvides

Abstract:

These This paper looks into frameworks which aim at furthering the discussion of the role of regenerative design practices in a city-s historic core and the tool of urban design to achieve urban revitalization on the island of Cyprus. It also examines the region-s demographic mix, the effectiveness of its governmental coordination and the strategies of adaptive reuse and strategic investments in older areas with existing infrastructure. The two main prongs of investigation will consider the effect of the existing and proposed changes in the physical infrastructure and fabric of the city, as well as the catalytic effect of sustainable urban design practices. Through this process, the work hopes to integrate the contained potential within the existing historic core and the contributions and participation of the migrant and immigrant populations to the local economy. It also examines ways in which this coupling of factors can bring to the front the positive effects of this combined effort on an otherwise sluggish local redevelopment effort. The data for this study is being collected and organized as part of ongoing urban design and development student workshop efforts in urban planning and design education. The work is presented in graphic form and includes data collected from interviews with study area organizations and the community at large. Planning work is also based on best practices initiated by the staff of the Nicosia Master Plan task force, which coordinates holistic planning efforts for the historic center of the city of Nicosia.

Keywords: Urban Design, Urban Development, Urban Regeneration, Historic Core, Cultural Planning.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1674

Authors: Rehab Abdullah Shendi

Abstract:

The use of customised soft-core processors in which instructions can be integrated into a system in application hardware is increasing in the Field Programmable Gate Array (FPGA) field. Specifically, the partial run-time reconfiguration of FPGAs in specialised processors for a particular domain can be very beneficial. In this report, the design and implementation for the customisation of a soft-core MIPS processor using an FPGA and partial reconfiguration (PR) of FPGA technology will be addressed to achieve efficient resource use. This can be achieved using a PR design flow that helps the design fit into a smaller device. Moreover, the impact of static power consumption could be reduced due to runtime reconfiguration. This will be done by configurable custom instructions implemented in the hardware as an extension on the MIPS CPU. The aim of this project is to investigate the PR of FPGAs for run-time adaptations of the instruction set of a soft-core CPU, including the integration of custom instructions and the exploration of the potential to use the MultiBoot feature available in Xilinx FPGAs to carry out the PR process. The system will be evaluated and tested on a Nexus 3 development board featuring a Xilinx Spartran-6 FPGA. The system will be able to load reconfigurable custom instructions dynamically into user programs with the help of the trap handler when the custom instruction is called by the MIPS CPU. The results of this experiment demonstrate that custom instructions in hardware can speed up a certain function and many instructions can be saved when compared to a software implementation of the same function. Implementing custom instructions in hardware is perfectly possible and worth exploring.

Keywords: Customisation, FPGA, MIPS, partial reconfiguration.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1186

Authors: M.E.khosroshahi , M.S.Nourbakhsh

Abstract:

Wet chemistry methods are used to prepare the SiO2/Au nanoshells. The purpose of this research was to synthesize gold coated SiO2 nanoshells for biomedical applications. Tunable nanoshells were prepared by using different colloidal concentrations. The nanoshells are characterized by FTIR, XRD, UV-Vis spectroscopy and atomic force microscopy (AFM). The FTIR results confirmed the functionalization of the surfaces of silica nanoparticles with NH2 terminal groups. A tunable absorption was observed between 470-600 nm with a maximum range of 530-560 nm. Based on the XRD results three main peaks of Au (111), (200) and (220) were identified. Also AFM results showed that the silica core diameter was about 100 nm and the thickness of gold shell about 10 nm.

Keywords: Gold nanoshells, Synthesis, UV-vis spectroscopy, XRD, AFM

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 3279

Authors: Sachin Kumar, Vivek Tiwari, Goutam Dutta

Abstract:

The paper investigates parallel channel instabilities of natural circulation boiling water reactor. A thermal-hydraulic model is developed to simulate two-phase flow behavior in the natural circulation boiling water reactor (NCBWR) with the incorporation of ex-core components and recirculation loop such as steam separator, down-comer, lower-horizontal section and upper-horizontal section and then, numerical analysis is carried out for parallel channel instabilities of the reactor undergoing both in-phase and out-of-phase modes of oscillations. To analyze the relative effect on stability of the reactor due to inclusion of various ex-core components and recirculation loop, marginal stable point is obtained at a particular inlet enthalpy of the reactor core without the inclusion of ex-core components and recirculation loop and then with the inclusion of the same. Numerical simulations are also conducted to determine the relative dominance between two modes of oscillations i.e. in-phase and out-of-phase. Simulations are also carried out when the channels are subjected to asymmetric power distribution keeping the inlet enthalpy same.

Keywords: Asymmetric power distribution, Density wave oscillations, In-phase and out-of-phase modes of instabilities, Natural circulation boiling water reactor

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2260

Authors: Mohammad Gholizadeh, Khairun Yahya, Anita Talib, Omar Ahmad

Abstract:

The distribution of macrobenthic polychaetes along the coastal waters of Penang National Park was surveyed to estimate the effect of various environmental parameters at three stations (200m, 600m and 1200m) from the shoreline, during six sampling months, from June 2010 to April 2011.The use of polychaetes in descriptive ecology is surveyed in the light of a recent investigation particularly concerning the soft bottom biota environments. Polychaetes, often connected in the former to the notion of opportunistic species able to proliferate after an enhancement in organic matter, had performed a momentous role particularly with regard to effected soft-bottom habitats. The objective of this survey was to investigate different environment stress over soft bottom polychaete community along Teluk Ketapang and Pantai Acheh (Penang National Park) over a year period. Variations in the polychaete community were evaluated using univariate and multivariate methods. The results of PCA analysis displayed a positive relation between macrobenthic community structures and environmental parameters such as sediment particle size and organic matter in the coastal water. A total of 604 individuals were examined which was grouped into 23 families. Family Nereidae was the most abundant (22.68%), followed by Spionidae (22.02%), Hesionidae (12.58%), Nephtylidae (9.27%) and Orbiniidae (8.61%). It is noticeable that good results can only be obtained on the basis of good taxonomic resolution. We proposed that, in monitoring surveys, operative time could be optimized not only by working at a highertaxonomic level on the entire macrobenthic data set, but by also choosing an especially indicative group and working at lower taxonomic and good level.

Keywords: Polychaete families, environment parameters, Bioindicators, Pantai Acheh, Teluk Ketapang.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1999

Authors: G. K. Pandey, D. Ramadasu, I. Banerjee, V. Vinod, G. Padmakumar, V. Prakash, K. K. Rajan

Abstract:

Detailed thermal hydraulic investigations are very  essential for safe and reliable functioning of liquid metal cooled fast  breeder reactors. These investigations are further more important for  components with complex profile, since there is no direct correlation  available in literature to evaluate the hydraulic characteristics of such  components directly. In those cases available correlations for similar  profile or geometries may lead to significant uncertainty in the  outcome. Hence experimental approach can be adopted to evaluate  these hydraulic characteristics more precisely for better prediction in  reactor core components.  Prototype Fast Breeder Reactor (PFBR), a sodium cooled pool  type reactor is under advanced stage of construction at Kalpakkam,  India. Several components of this reactor core require hydraulic  investigation before its usage in the reactor. These hydraulic  investigations on full scale models, carried out by experimental  approaches using water as simulant fluid are discussed in the paper. 

Keywords: Fast Breeder Reactor, Cavitation, pressure drop, Reactor components.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2936

Authors: Nerey H. Mvungi, Mosses Makoko

Abstract:

In today-s highly globalised and competitive world access to information plays key role in having an upper hand between business rivals. Hence, proper protection of such crucial resource is core to any modern business. Implementing a successful information security system is basically centered around three pillars; technical solution involving both software and hardware, information security controls to translate the policies and procedure in the system and the people to implement. This paper shows that a lot needs to be done for countries adapting information technology to process, store and distribute information to secure adequately such core resource.

Keywords: security, information systems, controls, technology, practices.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2612

Authors: J. Ruenin, S. Sukprasong, R. Phatthanakun, N. Chomnawang, P. Kuntanawat

Abstract:

In this paper, a simple microfluidic device for monitoring algal cell behavior is proposed. An array of algal microwells is fabricated by PDMS soft-lithography using X-ray LIGA mold, placed on a glass substrate. Two layers of replicated PDMS and substrate are attached by oxygen plasma bonding, creating a microchannel for the microfluidic system. Algal cell are loaded into the microfluidic device, which provides positive charge on the bottom surface of wells. Algal cells, which are negative charged, can be attracted to the bottom of the wells via electrostatic interaction. By varying the concentration of algal cells in the loading suspension, it is possible to obtain wells with a single cell. Liquid medium for cells monitoring are flown continuously over the wells, providing nutrient and waste exchange between the well and the main flow. This device could lead to the uncovering of the quantitative biology of the algae, which is a key to effective and extensive algal utilizations in the field of biotechnology, food industry and bioenergy research and developments.

Keywords: Algal cells, microfluidic device, X-ray LIGA, X-ray lithography, metallic mold, synchrotron light, PDMS

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2428

Authors: Nnamdi N. Omehe, Chibuzo Emeruwa

Abstract:

ZnIn2Se4 and ZnIn2Te4 are vacancy defect materials whose properties have been investigated using Density Functional Theory (DFT) framework. The pseudopotential method in conjunction with the LDA+U technique and the Projector Augmented Wave (PAW) was used to calculate the electronic band structure, total density of state, and the partial density of state; while the norm-conserving pseudopotential was used to calculate the dielectric response function with scissors shift. Both ZnIn2Se4 and ZnIn2Te4 were predicted to be semiconductors with energy band gap of 1.66 eV and 1.33 eV respectively, and they both have direct energy band gap at the gamma point of high symmetry. The topmost valence subband for ZnIn2Se4 and ZnIn2Te4 has an energy width of 5.7 eV and 6.0 eV respectively. The calculations of partial density of state (PDOS) show that for ZnIn2Se4, the top of the valence band is dominated by Se-4p orbital, while the bottom of the conduction band is composed of In-5p, In-5s, and Zn-4s states. PDOS for ZnIn2Te4, shows that the top of the valence band is mostly of Te-5p states, while its conduction band bottom is composed mainly of Zn-4s, Te-5p, Te-5s, and In-5s states. Dielectric response function calculation yielded (0) of 11.9 and 36 for ZnIn2Se4 and ZnIn2Te4 respectively.

Keywords: Optoelectronic, Dielectric Response Function, LDA+U, band structure calculation.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 107