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Lightning Related Human Risks and Risk Management
Issue:
Volume 2, Issue 5, September 2017
Pages:
65-79
Received:
28 June 2017
Accepted:
12 July 2017
Published:
15 August 2017
Abstract: A comprehensive account of lightning related hazards to human beings, both at general locations and at work place has been given. The injury mechanisms are analyzed from both engineering and medical perspectives with the view of determining the factors to be considered in risk assessment for minimizing adverse impacts of lightning from both direct and indirect effects. The paper provides practical approaches in evaluating the degree of risk of lightning related injury to humans at nearly any given location. The paper highlights many dependent and independent parameters in determining safety assessment schemes against lightning-related human hazard. It also emphasizes the need for development of human safety guidelines in addition to established lightning protection standards that focus on property and services. While most risk index parameters are valid globally, in some cases, there may be special regional or local factors that should be considered.
Abstract: A comprehensive account of lightning related hazards to human beings, both at general locations and at work place has been given. The injury mechanisms are analyzed from both engineering and medical perspectives with the view of determining the factors to be considered in risk assessment for minimizing adverse impacts of lightning from both direct ...
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Truncated Hybrid Double Acceptance Sampling Plan (THDASP) for Weibull Product Life Distribution
Braimah Odunayo Joseph,
Osanaiye Peter Asanaiye
Issue:
Volume 2, Issue 5, September 2017
Pages:
80-88
Received:
20 March 2017
Accepted:
17 April 2017
Published:
23 October 2017
Abstract: In this paper, an improved reliable acceptance sampling plan (Truncated hybrid Double Acceptance Sampling Plan (THDASP)) is proposed for products life that follows Weibull distribution when the testing is truncated at a specified time (t). This type of inspection sampling plan can be used to save the testing time in practical situations. The optimal sample sizes (n) required for testing product quality to ascertain a true mean life is obtained under a given Maximum Allowable Percent Defective (β), test termination ratios and acceptance numbers(C). The operating characteristic (OC) values formula is being developed considering both the Producer’s and Consumer’s risk and the values are generated. The Mean Life Ratios and curves of the plan are examined with varying ratio of the true mean life to the specified life. The advantage of this inspection plan is that could it results in better economic reliability product quality testing that protects the producer from rejecting his good lots and consumers from accepting bad lots of finished products. The mean life ratio values will also guides the producer on how to improve on his product’s quality. A numerical example is also discussed for illustrative purpose.
Abstract: In this paper, an improved reliable acceptance sampling plan (Truncated hybrid Double Acceptance Sampling Plan (THDASP)) is proposed for products life that follows Weibull distribution when the testing is truncated at a specified time (t). This type of inspection sampling plan can be used to save the testing time in practical situations. The optima...
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A Cascaded NPC/H- Bridge Inverter with Superior Harmonic Content and Improved DC Link Voltage Control for Grid Interface Application
Issue:
Volume 2, Issue 5, September 2017
Pages:
89-105
Received:
2 May 2017
Accepted:
13 May 2017
Published:
23 October 2017
Abstract: Modeling of Cascaded Multilevel converter has put more emphasize on conventional cascaded H- bridge inverter. First a new phase shifted SPWM control algorithm for cascaded NPC/H-bridge inverter is proposed. Its Superior harmonic suppression is verified by comparing its harmonic spectrum with that of the conventional multicarrier approach. For DC- bus capacitor voltage control, a new, balance circuit is proposed. Because of its modularity, it is simple and can be easily incorporated in cascaded inverter model with any number of levels. Feedback controller design is presented with main focus on grid voltage regulation and overall system capacitor voltage balance. The validity of grid interface model and its control strategies is substantially confirmed by the extensive simulation results.
Abstract: Modeling of Cascaded Multilevel converter has put more emphasize on conventional cascaded H- bridge inverter. First a new phase shifted SPWM control algorithm for cascaded NPC/H-bridge inverter is proposed. Its Superior harmonic suppression is verified by comparing its harmonic spectrum with that of the conventional multicarrier approach. For DC- b...
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Regularization, Recognition and Complexity Estimation Methods of Automata Models of Discrete Dynamical Systems in Control Problem
Issue:
Volume 2, Issue 5, September 2017
Pages:
106-116
Received:
26 February 2017
Accepted:
26 April 2017
Published:
23 October 2017
Abstract: In paper are considered laws of functioning of discrete determined dynamical systems and specific processes of functioning of such systems. As basic mathematical model of laws of functioning of systems are used automata models with a fundamentally new extension of these models to models with a countable infinite sets of states. This expansion is possible thanks to the proposed and developed by Tverdohlebov V. A. the mathematical apparatus of geometrical images of automaton mappings. Are presented results of development of regularization methods for partially set automata models of systems based on use of geometrical images of automatons mappings and numerical interpolation methods. Also in paper are considered a problem of complexity estimation of laws in a whole and specific processes of functioning of dynamic systems. For these purpose are used recurrent models and methods and also a specific mathematical apparatus of discrete riv-functions. Is spent classification by complexity estimations of automata models.
Abstract: In paper are considered laws of functioning of discrete determined dynamical systems and specific processes of functioning of such systems. As basic mathematical model of laws of functioning of systems are used automata models with a fundamentally new extension of these models to models with a countable infinite sets of states. This expansion is po...
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Infrasound Propagation of Finite Amplitude Wave in the Big Size Horn
Galyna Ivanovna Sokol,
Vladyslav Yurievich Kotlov,
Elena Sergeevna Mironenko,
Sergey Yurievich Kirichenko
Issue:
Volume 2, Issue 5, September 2017
Pages:
117-122
Received:
7 April 2017
Accepted:
21 April 2017
Published:
23 October 2017
Abstract: The analytical expressions, allowing analyzing the laws of increase and decrease of the second harmonic at excitation of the finite amplitude wave in the air-horn, are obtained. The distance, where the second harmonic propagating along the air-horn reaches its maximum, is determined. Comparative analysis for air-horns of different shapes is performed. All calculations were made for the horn, whose length is 10 meters and the diameter of the outlet section 4 meters. The resonant frequency of the acoustic signal in such a mouthpiece is 20 Hz.
Abstract: The analytical expressions, allowing analyzing the laws of increase and decrease of the second harmonic at excitation of the finite amplitude wave in the air-horn, are obtained. The distance, where the second harmonic propagating along the air-horn reaches its maximum, is determined. Comparative analysis for air-horns of different shapes is perform...
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Comparative Analysis on Speed Control of a Three Phase Induction Motor Drive Using Proportional Integral Differential and Scalar Closed Loop Fuzzy Logic Approach
Obinna Christopher Anyim,
Joseph Michael Môm,
Jonathan Uhaa Agber
Issue:
Volume 2, Issue 5, September 2017
Pages:
123-131
Received:
13 March 2017
Accepted:
12 April 2017
Published:
23 October 2017
Abstract: The principles of controlling an AC driven three phase induction motor employing constant volts/hertz (v/f) control method and the space vector pulse width modulation (SVPWM) technique are reviewed. The induction motor is one of the most common electrical motors in usage, owing to its unique characteristics. Its further application strength requires a robust, problem handling, fast and intelligent speed control system. As a result of this, developing an intelligent knowledge based fuzzy logic controller (FLC) became eminent, and on this basis, this paper is presented. By varying the motor speed with input reference speed, an error signal and a feedback loop is generated. The FLC then operates on the principles of mapping with corrective measure of an error signal generated and it is regulated by sets of programmable IF-THEN rules integrating the Mamdani fuzzy inference approach. The rules projected and formed are used to overcome drawbacks such as complexities and insensitivities to changes in model parameters associated to conventional controllers. The application of the constant v/f method was used to maintain constant voltage to frequency ratio, therefore, creating a constant magnetic field and a maximum torque throughout the operating range. This in turn generates a voltage and an angle command for the actualization of the SVPWM technique. This entire set up was repeated but now with a classical control method like the proportional integral differential (PID) controller. With a simulation time of 2s, results showed that with FLC, a better speed response can be achieved from a 5Hp 350V 50Hz AC motor attaining steady-state at 0.21s at no-load conditions. Simulation results showed a superior dynamic scheme of the FLC over the PI controller in terms of sensitivity to changes in model parameters. With a load torque of 10Nm applied at 1s, the FLC achieved stability at 1.2s still maintaining a constant speed of 157rads/s.
Abstract: The principles of controlling an AC driven three phase induction motor employing constant volts/hertz (v/f) control method and the space vector pulse width modulation (SVPWM) technique are reviewed. The induction motor is one of the most common electrical motors in usage, owing to its unique characteristics. Its further application strength require...
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PVT Analysis Reports of Akpet GT9 and GT12 Reservoirs
Okotie Sylvester,
Ofesi Samuel,
Ikporo Bibobra
Issue:
Volume 2, Issue 5, September 2017
Pages:
132-144
Received:
30 March 2017
Accepted:
31 July 2017
Published:
24 October 2017
Abstract: The estimation of the volume initial in place and the future performance prediction of hydrocarbon reservoir is associated with uncertainties in the geologic, petrophysical, PVT properties and production data. It is therefore important to a precisely characterize the reservoir fluid properties to successfully simulate the reservoir and size of facilities. To accurately describe these properties, the ideal process is to sample the reservoir fluid and perform a laboratory studies on the fluid samples. This study is carried out to evaluate the PVT properties of Akpet GT9 and GT12 reservoirs to determine parameters for oil in place evaluation, understand fluids behaviour during production and numerical simulations at the field scale. The PVT data was validated with Buckley and material balance plot and performed composition analysis for the reservoir fluids composition up to C11+ or C20+ and physical recombination for field gas-oil ratio (GOR) correction to ensure that the fluid sample used in the PVT analyses is representative.
Abstract: The estimation of the volume initial in place and the future performance prediction of hydrocarbon reservoir is associated with uncertainties in the geologic, petrophysical, PVT properties and production data. It is therefore important to a precisely characterize the reservoir fluid properties to successfully simulate the reservoir and size of faci...
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About One Method of Active Dynamic Damping
Teshaev Muhsin Кhudoyberdiyevich,
Yuliyev Ozod Olimovich,
Oripov Zayniddin Bakhtiyorovich
Issue:
Volume 2, Issue 5, September 2017
Pages:
145-149
Received:
31 March 2017
Accepted:
4 May 2017
Published:
24 October 2017
Abstract: In this article questions of active clearing of vibrations of system are considered. The paper deals with the active damping of the system's oscillations. Considering that the system is constrained by servosvyazami, for a single-mass system it is proposed to perform servosviaz by changing the mass of the absorber. For this it is proposed to build a digital tracking system.
Abstract: In this article questions of active clearing of vibrations of system are considered. The paper deals with the active damping of the system's oscillations. Considering that the system is constrained by servosvyazami, for a single-mass system it is proposed to perform servosviaz by changing the mass of the absorber. For this it is proposed to build a...
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Determination of Trip Attraction Rates of Shopping Centers in Uttara Area, Dhaka
Md. Shamim Al Razib,
Faysal Ibna Rahman
Issue:
Volume 2, Issue 5, September 2017
Pages:
150-155
Received:
31 March 2017
Accepted:
19 April 2017
Published:
24 October 2017
Abstract: Due to the high growth rate of urbanization in developing countries like Bangladesh leads to increase in vehicular traffic. Travel demand models are useful in managing the increased travel demand. So, Trip generation step is essential in planning of transportation facilities for Dhaka the capital of Bangladesh. In this study, the trip attraction rates of the shopping centers at Uttara Road, Uttara area of Dhaka are estimated by using trip rate analysis method. As part of this study, a total of six shopping centers are surveyed, for which the number of vehicles (car) and persons entering the shopping center during peak hour for every 15 minutes time interval are counted. The surveyed data deals with the relationship of trip attraction rates of the shopping center as a whole. Various physical features of the shopping centers are considered of this study, e.g total parking spaces, gross floor area, and the number of stores in the shopping center. This study will help for estimating the traffic volume of newly constructed shopping centers which has remarkable impact on the geometric design of roadways in the contiguous area.
Abstract: Due to the high growth rate of urbanization in developing countries like Bangladesh leads to increase in vehicular traffic. Travel demand models are useful in managing the increased travel demand. So, Trip generation step is essential in planning of transportation facilities for Dhaka the capital of Bangladesh. In this study, the trip attraction ra...
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Development of Cheap LM35-Based Air-Conditional Automation System
Issue:
Volume 2, Issue 5, September 2017
Pages:
156-159
Received:
17 April 2017
Accepted:
12 June 2017
Published:
24 October 2017
Abstract: Convenience, Comfort and Conservation are three undeniable products of Home Automation and Smart Home benefits. To this end, this work aimed to design, construct and implement a Cheap Air Conditional (AC) Automation System that schedules automatically when it should be ON or OFF based on the prevailing ambient temperature. Methods of Electrical/Electronic design and constructions were employed. The Sensor and Switching units were separately designed, constructed using electronic components and tested before and after casing. This system helps in making switching AC convenient for home owners/occupants by removing manual switching and at the same time improving comfort. Another benefit of this system is its ability to conserve energy by automatically switching off the AC when it senses it should not be on. It was evident - from the result- that this system can sense/detect the ambient temperature and switch on/off the AC.
Abstract: Convenience, Comfort and Conservation are three undeniable products of Home Automation and Smart Home benefits. To this end, this work aimed to design, construct and implement a Cheap Air Conditional (AC) Automation System that schedules automatically when it should be ON or OFF based on the prevailing ambient temperature. Methods of Electrical/Ele...
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