Search results for: Natural Gas Supply Chain.

Authors: Muhammad Salam, Nasir Rashid, Shah Khalid, Muhammad Raees Khan

Abstract:

In this paper a modified version NXM of traditional 5X5 playfair cipher is introduced which enable the user to encrypt message of any Natural language by taking appropriate size of the matrix depending upon the size of the natural language. 5X5 matrix has the capability of storing only 26 characters of English language and unable to store characters of any language having more than 26 characters. To overcome this limitation NXM matrix is introduced which solve this limitation. In this paper a special case of Urdu language is discussed. Where # is used for completing odd pair and * is used for repeating letters.

Keywords: cryptography, decryption, encryption, playfair cipher, traditional cipher.

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Authors: Ian A. Grout

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In this paper, the design and development of a system to provide hand motion and gesture control of laboratory test equipment is considered and discussed. The Leap Motion controller is used to provide an input to control a laboratory power supply as part of an electronic circuit experiment. By suitable hand motions and gestures, control of the power supply is provided remotely and without the need to physically touch the equipment used. As such, it provides an alternative manner in which to control electronic equipment via a PC and is considered here within the field of human computer interaction (HCI).

Keywords: Control, hand gesture, human computer interaction, test equipment.

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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.

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Authors: Lv Xiaopeng, Bian Qiang, Yue Suge

Abstract:

A fully on-chip low drop-out (LDO) voltage regulator with 100pF output load capacitor is presented. A novel frequency compensation scheme using current buffer is adopted to realize single dominant pole within the unit gain frequency of the regulation loop, the phase margin (PM) is at least 50 degree under the full range of the load current, and the power supply rejection (PSR) character is improved compared with conventional Miller compensation. Besides, the differentiator provides a high speed path during the load current transient. Implemented in 0.18μm CMOS technology, the LDO voltage regulator provides 100mA load current with a stable 1.8V output voltage consuming 80μA quiescent current.

Keywords: capacitor-less LDO, frequency compensation, transient response, power supply rejection

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Authors: Yadan Mao, Chengwang Lei, John C. Patterson

Abstract:

The mixing of pollutions and sediments in near shore regions of natural water bodies depends heavily on the characteristics such as the strength and frequency of flow instability. In the present paper, the instability of natural convection induced by absorption of solar radiation in littoral regions is considered. Spectral analysis is conducted on the quasi-steady state flow to reveal the power and frequency modes of the instability at various positions. Results indicate that the power of instability, the number of frequency modes, the prominence of higher frequency modes, and the highest frequency mode increase with the offshore distance and/or Rayleigh number. Harmonic modes are present at relatively low Rayleigh numbers. For a given offshore distance, the position with the strongest power of instability is located adjacent to the sloping bottom while the frequency modes are the same over the local depth. As the Rayleigh number increases, the unstable region extends toward the shore.

Keywords: Instability, Littoral waters, natural convection, Spectral analysis

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Authors: Jessica Lòpez Espejel, Mahaman Sanoussi Yahaya Alassan, Walid Dahhane, El Hassane Ettifouri

Abstract:

Pretrained transformer-based models have shown high performance in natural language generation task. However, a new wave of interest has surged: automatic programming language generation. This task consists of translating natural language instructions to a programming code. Despite the fact that well-known pretrained models on language generation have achieved good performance in learning programming languages, effort is still needed in automatic code generation. In this paper, we introduce JaCoText, a model based on Transformers neural network. It aims to generate java source code from natural language text. JaCoText leverages advantages of both natural language and code generation models. More specifically, we study some findings from the state of the art and use them to (1) initialize our model from powerful pretrained models, (2) explore additional pretraining on our java dataset, (3) carry out experiments combining the unimodal and bimodal data in the training, and (4) scale the input and output length during the fine-tuning of the model. Conducted experiments on CONCODE dataset show that JaCoText achieves new state-of-the-art results.

Keywords: Java code generation, Natural Language Processing, Sequence-to-sequence Models, Transformers Neural Networks.

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Authors: Gang Li, Ghulam Mubashar Hassan, Arcady Dyskin, Cara MacNish

Abstract:

Digital image correlation (DIC) is a contactless fullfield displacement and strain reconstruction technique commonly used in the field of experimental mechanics. Comparing with physical measuring devices, such as strain gauges, which only provide very restricted coverage and are expensive to deploy widely, the DIC technique provides the result with full-field coverage and relative high accuracy using an inexpensive and simple experimental setup. It is very important to study the natural patterns effect on the DIC technique because the preparation of the artificial patterns is time consuming and hectic process. The objective of this research is to study the effect of using images having natural pattern on the performance of DIC. A systematical simulation method is used to build simulated deformed images used in DIC. A parameter (subset size) used in DIC can have an effect on the processing and accuracy of DIC and even cause DIC to failure. Regarding to the picture parameters (correlation coefficient), the higher similarity of two subset can lead the DIC process to fail and make the result more inaccurate. The pictures with good and bad quality for DIC methods have been presented and more importantly, it is a systematic way to evaluate the quality of the picture with natural patterns before they install the measurement devices.

Keywords: Digital image correlation (DIC), Deformation simulation, Natural pattern, Subset size.

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Authors: Zeeshan Hamid, Sarwar Mehmood Azhar, Hammad Basir

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In today’s era, it is no news that organizations should demonstrate honest conduct as well as ethical administration. Therefore, the concept of corporate social responsibility (subsequently CSR) has created its tag upon the company’s focal point as well as marketing communications, and will continue in the future. The importance of CSR has increased in the last decade, and this concept has attracted global attention. The notion of CSR has strategic significance for many organizations. However, businesses are not adapting the activities of CSR that benefit to all of its stakeholders (including society). The main reason is the practitioners are unfortunately unable to comprehend its importance; and therefore, the activities of the CSR are so detached from the business activities. Hence, it is required to develop an understanding that the activities of CSR are not only beneficial for the society but it also benefit to business. This paper focuses on the concept of strategic CSR, and develops a theoretical framework that will help practitioners to filter and chose the activities of CSR that are strategic in nature.

Keywords: Economic responsibility, ethical responsibility, legal responsibility, philanthropic responsibility, strategic corporate social responsibility, value chain activities filter.

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Authors: Farnaz Amin Salehi, David Edward.Cotton, Mohammad Ali Abdoli, Kambiz Rezapour

Abstract:

The daily increase of organic waste materials resulting from different activities in the country is one of the main factors for the pollution of environment. Today, with regard to the low level of the output of using traditional methods, the high cost of disposal waste materials and environmental pollutions, the use of modern methods such as anaerobic digestion for the production of biogas has been prevailing. The collected biogas from the process of anaerobic digestion, as a renewable energy source similar to natural gas but with a less methane and heating value is usable. Today, with the help of technologies of filtration and proper preparation, access to biogas with features fully similar to natural gas has become possible. At present biogas is one of the main sources of supplying electrical and thermal energy and also an appropriate option to be used in four stroke engine, diesel engine, sterling engine, gas turbine, gas micro turbine and fuel cell to produce electricity. The use of biogas for different reasons which returns to socio-economic and environmental advantages has been noticed in CHP for the production of energy in the world. The production of biogas from the technology of anaerobic digestion and its application in CHP power plants in Iran can not only supply part of the energy demands in the country, but it can materialize moving in line with the sustainable development. In this article, the necessity of the development of CHP plants with biogas fuels in the country will be dealt based on studies performed from the economic, environmental and social aspects. Also to prove the importance of the establishment of these kinds of power plants from the economic point of view, necessary calculations has been done as a case study for a CHP power plant with a biogas fuel.

Keywords: Anaerobic Digestion, Biogas, CHP, Organic Wastes

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Authors: Shen-Kuei Du, Jen-Chieh Chang, Chia-Hong Kao, Tzu-Chen Hung, Chii-Ray Lin

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This study experimentally investigates the heat transfer effects of forced convection and natural convection under different substrate openings design. A computational fluid dynamics (CFD) model was established and implemented to verify and explain the experimental results and heat transfer behavior. It is found that different opening position will destroy the growth of the boundary layer on substrates to alter the cooling ability for both forced under low Reynolds number and natural convection. Nevertheless, having too many opening may reduce heat conduction and affect the overall heat transfer performance. This study provides future researchers with a guideline on designing and electronic package manufacturing.

Keywords: electronic cooling, experiment, opening concept, CFD.

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Authors: R. Abdulrahman, I. Sebastine

Abstract:

Natural gas is the most popular fossil fuel in the current era and future as well. Natural gas is existed in underground reservoirs so it may contain many of non-hydrocarbon components for instance, hydrogen sulfide, nitrogen and water vapor. These impurities are undesirable compounds and cause several technical problems for example, corrosion and environment pollution. Therefore, these impurities should be reduce or removed from natural gas stream. Khurmala dome is located in southwest Erbil-Kurdistan region. The Kurdistan region government has paid great attention for this dome to provide the fuel for Kurdistan region. However, the Khurmala associated natural gas is currently flaring at the field. Moreover, nowadays there is a plan to recover and trade this gas and to use it either as feedstock to power station or to sell it in global market. However, the laboratory analysis has showed that the Khurmala sour gas has huge quantities of H2S about (5.3%) and CO2 about (4.4%). Indeed, Khurmala gas sweetening process has been removed in previous study by using Aspen HYSYS. However, Khurmala sweet gas still contents some quintets of water about 23 ppm in sweet gas stream. This amount of water should be removed or reduced. Indeed, water content in natural gas cause several technical problems such as hydrates and corrosion. Therefore, this study aims to simulate the prospective Khurmala gas dehydration process by using Aspen HYSYS V. 7.3 program. Moreover, the simulation process succeeded in reducing the water content to less than 0.1ppm. In addition, the simulation work is also achieved process optimization by using several desiccant types for example, TEG and DEG and it also study the relationship between absorbents type and its circulation rate with HCs losses from glycol regenerator tower.

Keywords: Aspen Hysys, Process simulation, gas dehydration, process optimization.

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Authors: Pirada Techaratpong

Abstract:

This research aims to study value-creation process of producing monk-s bowls, Thai traditional handicrafts, which is facing problems in adapting to the changing society. It also aims to identify problems and obstacles to value creation. This research is based on a case study of monk-s bowl manufactures from Ban-Baat Village, Bangkok. The conceptual framework is based on the model of value chain to analyze the process. The research methodology is qualitative. This research found that the value-creation process of monk-s bowls consists of eight activities contributing to adding value to the products and increasing profits to the producers in return. Five major problems and obstacles are found. The research suggests that these problems and obstacles limit the manufacturers- potential for creating more valued product and lead to business stagnation. These problems should be addressed and solved with collaboration among the government, the private sector and the manufacturers.

Keywords: Craft manufacturing, problems and obstacles, value chain, value creation.

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Authors: Meryem Kanzari, Rabah Boukhanouf, Hatem G. Ibrahim

Abstract:

Indirect Evaporative Cooling process has the advantage of supplying cool air at constant moisture content. However, such system can only supply air at temperatures above wet bulb temperature. This paper presents a mathematical model for a Sub-wet bulb temperature indirect evaporative cooling arrangement that can overcome this limitation and supply cool air at temperatures approaching dew point and without increasing its moisture content. In addition, the use of porous ceramics as wet media materials offers the advantage of integration into building elements. Results of the computer show the proposed design is capable of cooling air to temperatures lower than the ambient wet bulb temperature and achieving wet bulb effectiveness of about 1.17.

Keywords: Indirect evaporative cooling, porous ceramic, sub-wet bulb temperature.

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Authors: Fernanda M. Assef, Maria Teresinha A. Steiner, David Gabriel F. de Barros

Abstract:

Review researches are useful in terms of analysis of research problems. Between the types of review documents, we commonly find bibliometric studies. This type of application often helps the global visualization of a research problem and helps academics worldwide to understand the context of a research area better. In this document, a bibliometric view surrounding clustering techniques and sustainability problems is presented. The authors aimed at which issues mostly use clustering techniques and even which sustainability issue would be more impactful on today’s moment of research. During the bibliometric analysis, we found 10 different groups of research in clustering applications for sustainability issues: Energy; Environmental; Non-urban Planning; Sustainable Development; Sustainable Supply Chain; Transport; Urban Planning; Water; Waste Disposal; and, Others. Moreover, by analyzing the citations of each group, it was discovered that the Environmental group could be classified as the most impactful research cluster in the area mentioned. After the content analysis of each paper classified in the environmental group, it was found that the k-means technique is preferred for solving sustainability problems with clustering methods since it appeared the most amongst the documents. The authors finally conclude that a bibliometric assessment could help indicate a gap of researches on waste disposal – which was the group with the least amount of publications – and the most impactful research on environmental problems.

Keywords: Bibliometric assessment, clustering, sustainability, territorial partitioning.

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Authors: A. Vasan

Abstract:

Particle swarm optimization (PSO) technique is applied to design the water distribution pipeline network. A simulation-optimization model is formulated with the objective of minimizing cost and is applied to a benchmark water distribution system optimization problem. The benchmark problem taken for the application of PSO technique to optimize the pipe size of the water distribution network is New York City water supply system problem. The results from the analysis infer that PSO is a potential alternative optimization technique when compared to other heuristic techniques for optimal sizing of water distribution systems.

Keywords: Water distribution systems, Optimization, Particle swarm optimization, Swarm intelligence, New York water supply system.

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Authors: Binu Thomas, Raju G., Sonam Wangmo

Abstract:

In Data mining, Fuzzy clustering algorithms have demonstrated advantage over crisp clustering algorithms in dealing with the challenges posed by large collections of vague and uncertain natural data. This paper reviews concept of fuzzy logic and fuzzy clustering. The classical fuzzy c-means algorithm is presented and its limitations are highlighted. Based on the study of the fuzzy c-means algorithm and its extensions, we propose a modification to the cmeans algorithm to overcome the limitations of it in calculating the new cluster centers and in finding the membership values with natural data. The efficiency of the new modified method is demonstrated on real data collected for Bhutan-s Gross National Happiness (GNH) program.

Keywords: Adaptive fuzzy clustering, clustering, fuzzy logic, fuzzy clustering, c-means.

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Authors: Belkacem Selma, Boumediene Selma, Samira Chouraqui, Hanifi Missoum, Tourkia Guerzou

Abstract:

Natural disasters have occurred and will continue to cause human and material damage. Therefore, the idea of "preventing" natural disasters will never be possible. However, their prediction is possible with the advancement of technology. Even if natural disasters are effectively inevitable, their consequences may be partly controlled. The rapid growth and progress of artificial intelligence (AI) had a major impact on the prediction of natural disasters and risk assessment which are necessary for effective disaster reduction. Earthquake prediction to prevent the loss of human lives and even property damage is an important factor; that, is why it is crucial to develop techniques for predicting this natural disaster. This study aims to analyze the ability of artificial neural networks (ANNs) to predict earthquakes that occur in a given area. The used data describe the problem of high energy (higher than 104 J) seismic bumps forecasting in a coal mine using two long walls as an example. For this purpose, seismic bumps data obtained from mines have been analyzed. The results obtained show that the ANN is able to predict earthquake parameters with  high accuracy; the classification accuracy through neural networks is more than 94%, and the models developed are efficient and robust and depend only weakly on the initial database.

Keywords: Earthquake prediction, artificial intelligence, AI, Artificial Neural Network, ANN, seismic bumps.

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Authors: A. R. Malekpour, A.R. Seifi

Abstract:

This paper discusses a genetic algorithm (GA) based optimal load shedding that can apply for electrical distribution networks with and without dispersed generators (DG). Also, the proposed method has the ability for considering constant and variable capacity deficiency caused by unscheduled outages in the bulked generation and transmission system of bulked power supply. The genetic algorithm (GA) is employed to search for the optimal load shedding strategy in distribution networks considering DGs in two cases of constant and variable modelling of bulked power supply of distribution networks. Electrical power distribution systems have a radial network and unidirectional power flows. With the advent of dispersed generations, the electrical distribution system has a locally looped network and bidirectional power flows. Therefore, installed DG in the electrical distribution systems can cause operational problems and impact on existing operational schemes. Introduction of DGs in electrical distribution systems has introduced many new issues in operational and planning level. Load shedding as one of operational issue has no exempt. The objective is to minimize the sum of curtailed load and also system losses within the frame-work of system operational and security constraints. The proposed method is tested on a radial distribution system with 33 load points for more practical applications.

Keywords: DG, Load shedding, Optimization, Capacity Deficiency Modelling.

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Authors: Rishabh Garg

Abstract:

Traditionally, business parties build trust with a centralized operating mechanism, such as payment by letter of credit. However, the increase in cyber-attacks and malicious hacking has jeopardized business operations and finance practices. Emerging markets, due to their high banking risks and the large presence of digital financing, are looking for technology that enables transparency and traceability of any transaction in trade, finance or supply chain management. Blockchain systems, in the absence of any central authority, enable transactions across the globe with the help of decentralized applications. DApps consist of a front-end, a blockchain back-end, and middleware, that is, the code that connects the two. The front-end can be a sophisticated web app or mobile app, which is used to implement the functions/methods on the smart contract. Web apps can employ technologies such as HTML, CSS, React and Express. In this wake, fintech and blockchain products are popping up in brokerages, digital wallets, exchanges, post-trade clearance, settlement, middleware, infrastructure and base protocols. The present paper provides a technology driven solution, financial inclusion and innovative working paradigm for business and finance.

Keywords: Authentication, blockchain, channel, cryptography, DApps, data portability, Decentralized Public Key Infrastructure, Ethereum, hash function, Hashgraph, Privilege creep, Proof of Work algorithm, revocation, storage variables, Zero Knowledge Proof.

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Authors: T. Basitah

Abstract:

This study was to explore and utilize the fresh rind of mangosteen Index Colour 5 as an upcoming raw material for the production of natural dyes. Rind from the fresh mangosteen Index Colour 5 was utilized to extract the dyes. The established extracts were experimented on silk fabrics via three types of mordanting and dyeing procedures; pre-mordanting, simultaneous mordanting and post-mordanting. As a result, the applications of the freeze-drying methodology and mechanizable equipment have helped to produce excellent range of natural colours. Silk fabric treated simultaneously with mordanting and dyeing with extract dye Index Colour 5 produced a brilliant shade of the red colour and the colour from this index is also discovered sensitive to light and washing during the fastness tests. The preliminary evaluation and instrumentation analysis allowed us to examine whether the application of different mordanting and dyeing procedures with the same extract samples and concentrations affected the colours and shades of the fabric samples.

Keywords: Natural dye, Freeze-drying, Garcinia mangostana Linn, Mordanting.

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Authors: Charles P. Mukumba, Kahilu K. Shakantu

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Achieving the Sustainable Development Goals (SDGs) is critical to achieving transformational results that support Zambia's developmental agenda. Public procurement is integral to the government's mission to deliver goods and services in a timely and economical manner beyond the value of money spent. This study explores the link between sustainable public procurement and the SDGs in Zambia. To validate the established links with public sector procurement in Zambia, the study employed qualitative research using semi-structured interviews with 12 public procurement officials. The collected data were analysed using thematic analysis. The findings indicate that public procurement plays a fundamental role in achieving the SDGs by helping deliver core public services that support SDGs and systematizing and co-delivering added value along the way. The study further established the importance of sustainable public procurement within the development context. The interviews were limited to mainstream public sector procurement entities in Lusaka, Zambia. Sustainable public procurement actions have the potential to impact SDGs. Promoting sustainable public procurement will enhance sustainable development and significantly improve the supply chain, benefiting the economy, society and environment. Findings will inform policy-makers how to strategically design sustainable public procurement policy by attuning it to procuring entities' objectives and priorities to contribute to attaining SDGs.

Keywords: Sustainable public procurement, sustainable development goals, SDG targets, Zambia.

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Authors: Foad Nazari, Seyed Mahmood Hosseini, Mohammad Hossein Abolbashari, Mohammad Hassan Abolbashari

Abstract:

The present study is concerned with the optimal design of functionally graded plates using particle swarm optimization (PSO) algorithm. In this study, meshless local Petrov-Galerkin (MLPG) method is employed to obtain the functionally graded (FG) plate’s natural frequencies. Effects of two parameters including thickness to height ratio and volume fraction index on the natural frequencies and total mass of plate are studied by using the MLPG results. Then the first natural frequency of the plate, for different conditions where MLPG data are not available, is predicted by an artificial neural network (ANN) approach which is trained by back-error propagation (BEP) technique. The ANN results show that the predicted data are in good agreement with the actual one. To maximize the first natural frequency and minimize the mass of FG plate simultaneously, the weighted sum optimization approach and PSO algorithm are used. However, the proposed optimization process of this study can provide the designers of FG plates with useful data.

Keywords: Optimal design, natural frequency, FG plate, hybrid meshless method, MLPG method, ANN approach, particle swarm optimization.

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Authors: Djalal Hamed

Abstract:

The aim of this paper is to perform, by mean of the finite volume method, a numerical solution of the transient natural convection in a narrow rectangular channel between two vertical parallel Material Testing Reactor (MTR)-type fuel plates, imposed under a heat flux with a cosine shape 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 reach a specific safety limits (90 °C). For this purpose, a computer program is developed to determine the principal parameters 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 core power. Throughout the obtained results, we noticed that the core power should not reach 400 kW, to ensure a safe passive residual heat removing from the nuclear core by the upward natural convection cooling mode.

Keywords: Buoyancy force, friction force, friction factor, finite volume method, transient natural convection, thermal hydraulic analysis, vertical heated rectangular channel.

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Authors: H. Kazemi Karegar, S. Jalilzadeh, V. Nabaei, A. Shabani

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In this paper, the problem of finding the optimal topological configuration of a deregulated distribution network is considered. The new features of this paper are proposing a multiobjective function and its application on deregulated distribution networks for finding the optimal configuration. The multi-objective function will be defined for minimizing total Energy Supply Costs (ESC) and energy losses subject to load flow constraints. The optimal configuration will be obtained by using Binary Genetic Algorithm (BGA).The proposed method has been tested to analyze a sample and a practical distribution networks.

Keywords: Binary Genetic Algorithm, Deregulated Distribution Network, Minimizing Cost, Reconfiguration.

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Authors: Olufisayo A. Olufayo, Fred A. O. Otieno, George M. Ochieng

Abstract:

Abstraction of water from the dry river sand-beds is well-known as an alternative source of water during dry seasons. Internally, because of the form of sand particles, voids are created which can store water in the riverbeds. Large rivers are rare in South Africa. Many rivers are sand river types and without water during the prolonged dry periods. South Africa has not taken full advantage of water storage in sand as a solution to the growing water scarcity both in urban and rural areas. The paper reviews the benefits of run-off storage in sand reservoirs gained from other arid areas and need for adoption in rural areas of South Africa as an alternative water supply where it is probable.

Keywords: Groundwater, Perennial river, Run-off storage, Sandreservoir.

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Authors: Suparman

Abstract:

Piecewise polynomial regression model is very flexible model for modeling the data. If the piecewise polynomial regression model is matched against the data, its parameters are not generally known. This paper studies the parameter estimation problem of piecewise polynomial regression model. The method which is used to estimate the parameters of the piecewise polynomial regression model is Bayesian method. Unfortunately, the Bayes estimator cannot be found analytically. Reversible jump MCMC algorithm is proposed to solve this problem. Reversible jump MCMC algorithm generates the Markov chain that converges to the limit distribution of the posterior distribution of piecewise polynomial regression model parameter. The resulting Markov chain is used to calculate the Bayes estimator for the parameters of piecewise polynomial regression model.

Keywords: Piecewise, Bayesian, reversible jump MCMC, segmentation.

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Authors: Norzita Ngadi, John Abrahamson, Conan Fee, Ken Morison

Abstract:

Nonspecific protein adsorption generally occurs on any solid surfaces and usually has adverse consequences. Adsorption of proteins onto a solid surface is believed to be the initial and controlling step in biofouling. Surfaces modified with end-tethered poly(ethylene glycol) (PEG) have been shown to be protein-resistant to some degree. In this study, the adsorption of β-casein and lysozyme was performed on 6 different types of surfaces where PEG was tethered onto stainless steel by polyethylene imine (PEI) through either OH or NHS end groups. Protein adsorption was also performed on the bare stainless steel surface as a control. The adsorption was conducted at 23 °C and pH 7.2. In situ QCM-D was used to determine PEG adsorption kinetics, plateau PEG chain densities, protein adsorption kinetics and plateau protein adsorbed quantities. PEG grafting density was the highest for a NHS coupled chain, around 0.5 chains / nm2. Interestingly, lysozyme which has smaller size than β-casein, appeared to adsorb much less mass than that of β- casein. Overall, the surface with high PEG grafting density exhibited a good protein rejection.

Keywords: QCM-D, PEG, stainless steel, β-casein, lysozyme.

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Authors: Nasser Erfani Majd, Mojtaba Lotfizad

Abstract:

In this paper, an ultra low power and low jitter 12bit CMOS digitally controlled oscillator (DCO) design is presented. Based on a ring oscillator implemented with low power Schmitt trigger based inverters. Simulation of the proposed DCO using 32nm CMOS Predictive Transistor Model (PTM) achieves controllable frequency range of 550MHz~830MHz with a wide linearity and high resolution. Monte Carlo simulation demonstrates that the time-period jitter due to random power supply fluctuation is under 31ps and the power consumption is 0.5677mW at 750MHz with 1.2V power supply and 0.53-ps resolution. The proposed DCO has a good robustness to voltage and temperature variations and better linearity comparing to the conventional design.

Keywords: digitally controlled oscillator (DCO), low power, jitter; good linearity, robust

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Authors: Sarah Taheri, Shahram Ghanbari Pakdehi, Arash Rezaei

Abstract:

Natural gas usually includes H2S component which is very toxic, hazardous and corrosive to environment, human being and process equipments, respectively. Therefore, sweetening of the gas (separation of H2S) is inevitable. To achieve this purpose, using packed-bed columns with liquid absorbents such as MEA or DEA is very common. Due to some problems of usual packed columns especially high pressure drop of gas phase, a novel kind of them called wetted-wire column (WWC) has been invented. The column decreases the pressure drop significantly and improves the absorption efficiency. The packings are very thin rods (like wire) and as long as column. The column has 100 wires with a triangular arrangement and counter current flows of gas and liquid phases. The observation showed that at the same conditions, the absorption performance was quite comparable to conventional packed-bed towers and a very low pressure drop.

Keywords: H2S, Natural gas, separation, wetted-wire column (WWC).

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Authors: Galya Kapanen, Jaan–Mati Punning, Irina Blinova, Külli Kangur

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In this paper we discuss the problems of the long-term management policy of Lake Peipsi and the roles of natural and anthropogenic factors in the ecological state of the lake. The reduction of the pollution during the last 15 years could not give significant changes of the chemical composition of the water, what implicates the essential role that natural factors have on the ecological state of lake. One of the most important factors having impact on the hydrochemical cycles and ecological state is the hydrological regime which is clearly expressed in L. Peipsi. The absence on clear interrelations of climate cycles and nutrients suggest that complex abiotic and biotic interactions, which take place in the lake ecosystem, plays a significant role in the matter circulation mechanism within lake.

Keywords: Lake Peipsi, ecosystem, eutrophication, waterfluctuation, NAO.

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