International Journal of Advances in Applied Sciences
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Second order noise shaping for data-weighted averaging technique to improve sigma-delta DAC performance
Get PDFIn general, the noise shaping responses, a cyclic second-order response is delivered by the method of data weighted averaging (DWA) in which the output of the digital-to-analog converter (DAC) is restricted to one of two states. DWA works efficiently for rather low levels of quantizing; it begins presenting considerable difficulties when internal levels of quantizing are extended further. Though, each added bit of internal quantizing causes an exponentially increasing in power dissipation, complexity, and size of the DWA logic and the DAC. This gives a controlled second-order response accounting for the mismatch of the elements of DAC. The multi-bit DAC is made up of numerous single-bit DACs having values thereof chosen via a digital encoder. This research presents a discussion of the influence of mismatching between unit elements of the delta-sigma DAC. This results in a constrained second-order response accounting for a mismatch of DAC elements. The results of the simulation showed how the effectiveness of the DWA method in reducing band tones. Furthermore, the DWA method has proved its efficiency in solving the mismatching of DAC unit elements. The noise of the mismatching elements is enhanced by 11 dB at 0.01 with the proposed DWA, thereby enhancing the efficiency of the DAC in comparison to the efficiency of the DAC with no use of the circuit of DWA
A numerical algorithm to find a root of non-linearequations using householder’s method
Get PDFIn this paper, we propose a three step algorithm using Householder’s method for find-ing an approximate root of the given non-linear equations in one variable. Severalnumerical examples are presented to illustrate and validation of the proposed method.Implementation of the proposed algorithm in Maple is also discussed with samplecomputations
Design and implementation of an African native language-based programming language
Get PDFMost of the existing high-level programming languages have hitherto borrowed their lexical items from human languages including European and Asian languages. However, there is a paucity of research information on programming languages developed with the lexicons of an African indigenous language. This research explored the design and implementation of an African indigenous language-based programming language using Yoruba as a case study. Yoruba is the first language of over 30 million people in the southwest of Nigeria, Africa; and is spoken by over one hundred million people worldwide. It is hoped, as established by research studies, that making computer programming possible in one’s mother tongue will enhance computer-based problem-solving processes by indigenous learners and teachers. The alphabet and reserved words of the programming language were respectively formed from the basic Yoruba alphabet and standard Yoruba words. The lexical items and syntactic structures of the programming language were designed with appropriate regular expressions and context-free grammar, using Backus-Naur form (BNF) notations. A prototype implementation of the programming language was carried out as a source-to-source, 5-pass compiler. QBasic within QB64 IDE was the implementation language. The results from implementation showed the functional correctness and effectiveness of the developed programming language. Thus, lexical items of a programming language need not be borrowed exclusively from European and Asian languages, they can and should be borrowed from most African native languages. Furthermore, the developed native language programming language can be used to introduce computer programming to indigenous pupils of primary and junior secondary schools
Effects of autoclaving (Pleurotus osteratus) spent mushroom substrate water extract on the minerals, elicitors, cassava yield, and the management of African cassava mosaic virus
Get PDFFarmers all over the world spend millions of dollars to partially control plant diseases that attack their crops using agrochemicals that pollute the environment. Plant diseases reduce crop yield, quality, and shelf life. Enhancing the inherent ability of plants to resist diseases using elicitors and minerals is one of the neglected, sustainable, low-cost, and environmentally friendly approaches to ensure the continued supply of food and fiber. Therefore the aim of this paper is to evaluate the composition of the elicitors and minerals in autoclaved and unautoclaved water extract of Pleurotus osteratus spent mushroom substrate and the effects of its application on the management of African cassava mosaic virus (ACMV), growth, and yield of cassava. The treatments for this investigation comprised Pleurotus osteratus water extract spent mushroom substrate (POWESMS), Pleurotus osteratus autoclaved spent mushroom substrate (POAWESMS), and untreated cassava plants as control. The mineral compositions and the elicitors in the treatments were evaluated using standard procedures. The data generated were subjected to analysis of variance (ANOVA) at (p=0.05). The results obtained from this investigation revealed significant differences in the values of resistant elicitors and minerals. Significant differences were also recorded for the growth, yield parameters, and disease severity evaluated at 4 weeks intervals. The results showed that unautoclaved water extract performed significantly better than the autoclaved in reducing African cassava mosaic disease (ACMD) severity which did not translate to higher crop yield
Application of PSO for optimal coordination of directional over-current relays in distribution system with distributed renewable energy sources
Get PDFThe use of distributed renewable energy sources (D-RES) in the electrical network has expanded greatly. However, integration of these resources into distribution systems caused more problems in protection related issues such as mis-coordination and changes the direction and value of fault currents. When connecting new D-RES to electrical power distribution networks, it is required to re-coordinate directional over-current relays (DOCR) to ensure the continuity of the power transmission when the short circuits take place. This work presented a particle swarm optimization (PSO) algorithm to determine two independent variables called pickup current (Ip) and time dial setting (TDS) for optimal setting of relays. From analysis result, the impacts of RES location in the distribution system on DOCRs had been observed on the optimal relays settings
Overview of microgrid systems
Get PDFThis research paper discusses the different types of microgrids, their structural arrangements and the technology adopted for different power management projects. It also deals with various control strategies and security plans used for optimal performance. A detailed overview of the direct current (DC) microgrid system is discussed, outlining its configurations and technical-economic aspects. Performance evaluation of microgrid carried out through various reliability codes is also provided
Hydrodynamic characteristics of marine composite propeller blade using a numerical approach
Get PDFThe aim of the present research work is to investigate the hydrodynamic characteristics (pressure distribution, rotational speed, thrust, and torque) of the conventional B-series composite propeller blade. The open water efficiency for the scaled model of the composite propeller blade is computed using computational fluid dynamics (CFD) fluent simulation tool. The obtained numerical results show that the propeller will operate at optimum efficiency for the given speed condition and perform with reduced efficiency at other operational speeds. The computed responses are also validated with the standard B-series data which verifies the accuracy and robustness of the present numerical approach in analyzing the performance characteristics of propellers. The deviation in solution ranges from 5 to 15% in the case of thrust, and 10 to 20% in the case of torque. Pressure estimation is usually quite accurate with a 5 to 8% variation. The tabular data of pressure distribution over the propeller blade may be used for further structural analysis
Real power loss diminution by rain drop optimization algorithm
Get PDFIn this work, the rain drop optimization (RDO) algorithm is projected to reduce power loss. Proceedings of rain drop have been imitated to model the RDO algorithm. The natural action of rain drop is flowing downwards from the peak and it may form small streams during the headway from the mountain or hill. As by gravitation principal rain drop flow as a stream as a river from the peak of mountains or hill then it reaches the sea as global optimum. Proposed rain drop optimization (RDO) algorithm evaluated in IEEE 30, bus test system. Power loss reduction, voltage deviation minimization, and voltage stability improvement have been achieved
On optimization of manufacturing of a step-down DC-DC converter to increase integration density of elements
Get PDFWe consider the possibility to increase the field-effect transistor's density in a switched-capacitor step-down DC-DC converter. Based on this approach we analyzed the manufacturing of the converter in a heterostructure with a special structure. Some specific sections of the heterostructure must be doped by ion implantation or by diffusion. After this procedure optimized annealing has been done. We also obtained conditions for decreasing mismatch-induced stress value in this heterostructure. An analytical approach for the analysis of heat and mass transport in multilayer structures has been introduced. The approach gives a possibility without crosslinking of solutions on interfaces between layers, taking into account (i) spatial variation of parameters of considered processes; (ii) temporal variation of parameters of considered processes; (iii) nonlinearity of considered processes; and (iv) mismatch-induced stress
Single phase seven level Z-source cascaded H-bridge inverter for photovoltaic systems
Get PDFThe multilevel inverter (MLI) is identified as a viable power electronic unit for distributed energy conversion applications. In this paper discusses the performance of a single phase seven level Z (impedance) source cascaded H-bridge inverter topology suited for solar photovoltaic systems. A modified sinusoidal pulse width modulation technique is used to control the switches of the H-bridge inverter. The simulation results are obtained in terms of inverter output voltage and harmonic analysis confirms improvement in voltage boost and reduction in harmonic distortion of the suggested inverter topology. The experimental results match the simulation values, as verified through a scaled-down prototype