Development of three phase back to back converter with current flow control using raspberry Pi microcontroller

A High-Voltage Direct Current (HVDC) electric power transmission system uses direct current form the bulk transmission of electrical power, in contrast with the common Alternating Current (AC) systems. For a long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses. The overall HVDC system is call back-to-back converter. Therefore, this project is to design and to develop a back-to-back converter with Proportional-Integrative-derivative (PID) control current that could be applied for the resistive load. The basic structure of the PID controller makes it easy to regulate the process output. The control technique is called a current control technique by comparing the output current with the reference current. Thus, the PID controller will force the output current to follow the reference current by creating and changing the pulse width modulation (PWM) signals. The PID controller is developed and simulated by using MATLAB/Simulink software and then implemented to the hardware by using Raspberry Pi Microcontroller. The result from the simulation shows that, the load current follows the reference current from 0 amperes until 1 amperes and the results from the experiment shows that the output current at the load follows the reference current from 0 amperes until 0.4 amperes. The high sensitivity of current sensor and also due to very low resolution of analogue to digital converter effect the result in this project. The results explanation of the project can be divided into three categories; simulation, open loop control and closed loop control

The mediating effects of buyer-supplier relationship on relationship of trust and commitment, and organization performance of agriculture based SMEs in Kelantan

Previous studies had justified that buyer-supplier relationship has a positive relationship with organization performance of SMEs. Plus, the positive relationship between trust and buyer-supplier relationship of SMEs also has been indicated in a past studies. However, not many researches were done to study the commitment effect on buyer-supplier relationship, and the mediating effect of buyer-supplier relationship with trust, commitment, and organization performance of SMEs. In addition, there are few researches done in primary agriculture based SMEs that are focusing on micro enterprise is and this situation needs to be changed since this sector has contributed 7.3% to the Malaysia Gross Domestic Product (GDP). This study fills up the gap by identifying the relationship of trust, commitment, buyer-supplier relationship and organization performance of primary agriculture based SME's concentrating on micro enterprise. Plus, this study has presented the hypothesis regarding this relationship. This study concentrates on SMEs' primary agriculture of micro enterprise type located in Kelantan, whereby Kelantan is the third ranking state with the most number SMEs‟ involvement in Malaysia with a total about 37, 823 SMEs. The questionnaires were distributed to 120 respondents and 100 questionnaires were returned back. However, two questionnaires had to be rejected because there were not fully completed. So, the total number of samples in this study is 98. A list of the respondents was retrieved from Jabatan Pertanian Negeri Kelantan, complete with an email address and contact number. The finding shows that there is a positive relationship between trust and commitment on buyer-supplier relationship, and there is a positive relationship between buyer-supplier relationship and organization performance of primary agriculture based SMEs in micro enterprise type. However, buyer-supplier relationship is a partial mediator of the relationship between trust and commitment to organization performance. The recommendation of the organization and future research were also discussed

Development in Synthesis of Silicon Carbide from Natural Resource

Silicon Carbide (SiC) is categorized as an important structural ceramic material because of its combination of excellence properties which are inherent due to highly covalent bonding. Composition of tetrahedral carbon and silicon atoms with strong bonds in crystal lattice resulted to very hard and strong SiC materials. Silica sands was chosen as the main resource of SiO2 and being the most abundant natural resources available in Tronoh, Perak is used as major reference of the project. The most fundamental synthesis development of SiC is the reduction process of SiO2 by carbonaceous material such as graphite and petroleum coke with addition of Al2O3 as additive. In this project, the development in synthesis of SiC from base materials silica oxide and graphite will be demonstrated using Low Energy Ball Milling and sintering techniques with significant low cost production and environmental concerns. The preparation for developing nano-crystalline particles of SiC is done by prolonged low energy milling process at constant speed of 100 rpm for 100 and 200 hours accordingly. The ball to powder weight ratio and operating speed are two key parameters of effective milling condition during milling and crucial introduce sufficient reaction energy to overcome the activation energy of SiC phase in the powder mixture. Throughout the experiment, comparison analysis between two time interval of milling on the X-ray diffraction (XRD) patterns has proven that the 200 h activated mixture revealed that SiC phase had been formed almost completely after reduction at temperature range from 1400oC to 1600oC. However, SiC crystalline has also developed during 100 h milling time with considerable amount. As the particle sizes and morphology behaviors are concerned, Field Emission Scanning Electron Microscopy (FESEM) was applied and finally revealed that the particle sizes of the powder mixture had been decreased from 63 μm to 300 nm due to the extending milling time. The SiO2 particles had been covered by carbon particles and it is proven that the nano-particles of SiC whiskers were developed using this combination techniqu

Hubungan sikap alam sekitar dan amalan kitar semula di negeri Terengganu.

Program kitar semula yang telah diperkenalkan oleh pihak berkuasa untuk mengurangkan penjanaan sisa pepejal gagal mencapai matlamatnya. Penjanaan sisa pepejal telah meningkat pada setiap tahun

Tun Seri Lanang: dari Istana Batu Sawar ke Naggaroe Acheh Darussalam

Tun Seri Lanang adalah seorang ahli politik dan pujangga ternama yang berasal dari istana Johor di Batu Sawar. Pada tahun 1613, Tun Seri Lanang telah di tawan oleh bala tentera Sultan Iskandar Muda Mahkota Alam dari Acheh, kemudian dibawa ke Acheh bersama-sama Sultan Alauddin Riayat Shah III dan adindanya Raja Abdullah. Sumber sejarah di Tanah Melayu menganggap Tun Seri Lanang meninggal dunia di Acheh. Peranannya selepas ditawan dan dibawa ke Acheh tidak banyak diperkatakan. Sungguh pun begitu, sumber-sumber sejarah dari Acheh menunjukkan bahawa Tun Seri Lanang tidak dipenjarakan atau meninggal dunia di dalam penjara, sebaliknya beliau telah dilantik menjadi Raja Samarlanga. Beliau juga dilantik menjadi penasihat kepada paduka Sultan Mahkota Alam dan dua orang penggantinya. Beliau mungkin telah diselamatkan atas pengaruh Raja Puteri Kamaliah, iaitu puteri Pahang yang telah dikahwini Sultan Iskandar Muda Mahkota Alam yang kemudiannya menjadi permaisuri Acheh. Artikel ini merupakan laporan penyelidikan mengenai kehidupan dan sumbangan Tun Seri Lanang semasa di Acheh. Pada masa ini Tun Seri Lanang menjadi tokoh kepada tiga buah negara iaitu Malaysia, Singapura dan Naggaroe Acheh Darussalam

A framework for an application based mobile cache consistency method.

In a mobile environment, maintaining cache consistency is challenging. Applying one type of consistency levels either strict or weak is not suitable all the time, as the consistency requirements mainly depend on the mobile application system and differ from one to another. Also forcing the mobile client to use its cache data for the purpose of reading only limits the functionality of the caching. The stateful scheme Multi-level Mobile Cache Consistency Protocol that works in client-server architecture supports different levels of consistency. The Mobile client is able to issue updates transactions, and determine the consistency requirements upon its interest. Based on the Multi-Level Mobile Cache Consistency Protocol this paper presents a framework of stateful strategy; Application Based Multi-level Mobile Cache Consistency Method (ABMMCCM) that preserves the advantages of multi-level mobile cache consistency protocol and enhances its drawbacks. In ABMMCCM the consistency requirements are designed at the server side based on the application requirements, and each data item has a single consistency requirement entry. The proposed framework is initially compared to Multi-level Mobile Cache Consistency Protocol, and it appears that ABMMCCM reduces the number of messages transfer between the base server and the mobile client, which helps in better utilizing the wireless network, and reduces the overhead from the mobile client and the base server

Conformable Fractional Differintegral Method For Solving Fractional Equations

The standard approaches to the problem of conformable fractional calculus has been studied extensively. Many researchers have shown that the obtained conditions for the theorem describing the general solution of; y a ( x ) y b ( x ) are generally weaker than those derived by using the classical norm-type expansion and compression theorem. In this paper, we propose conformable method for the fractional differential transform and established the prove for basic properties of differintegrals. Some solved examples have been reported to illustrate the possible application of the obtained results.The authors wish to thank A, B, C. This work was supported in part by a grant from XYZ

Modeling and simulating semantic social overlay peer-to-peer systems.

The complexity of Peer-to-Peer (P2P) systems makes their analytical evaluation complicated. To conquer this problem, simulation studies are usually used to evaluate such systems. However, evolution of P2P systems, from simply a Gnutella-like network to advanced overlays, makes their comparison difficult in a similar condition. Using different inputs, outputs and datasets is the main cause of this problem. On the other hand, network simulators cannot be used for such systems because of high scalability and dynamicity of P2P systems. Most network simulators can simulate few nodes in high detail without considering dynamicity of systems. In this study, a generic model, parameters and datasets are presented and used to design a flow-based P2P simulator with the capability of implementing different P2P protocols to simplify the evaluation of P2P systems. Then, the behavior of a semantic social overlay P2P system is investigated and compared with two various types of overlays, namely random and interest-based systems to show the applicability of the simulator. Although three different types of overlays have been chosen, the generic model and selected parameters used in the proposed simulator provide a uniform environment to evaluate and compare different types of overlays in similar conditions

A social network Peer-to-Peer model for peer clustering

Peer clustering is a way for managing the structure of Peer-to-Peer (P2P) networks. It can be done on physical structure of the network like physical proximity of peers or semantic relationship among them. Our proposed model uses social network concepts as the main physical structure for clustering peers. Nodes in the model are grouped into several communities and sub communities with similar interests. The order and relation among communities are defined and controlled by a shared ontology. This structure provides lower distance and better locality in search. A simulation of the model shows lower path and better clustering than a random network

ABMMCCS: Application based multi-level mobile cache consistency scheme

Maintaining cache consistency in mobile computing system is a critical issue due to the inheritance limitations in mobile environment such as limited network bandwidth and mobile device energy power.Most of the existing schemes maintaining mobile cache consistency support only one level of consistency that is either strict or weak which is not suitable all the time, as various mobile applications systems have different consistency requirements on their data.Also majority of the schemes restrict the using of cached data for reading only which is limits the functionality of the caching system.In this paper, a new scheme is proposed to maintain the mobile cache consistency in a single cell wireless network called Application Based Multi-Level Mobile Cache Consistency Scheme (ABMMCCS).The main idea in ABMMCCS is to be suitable to various real mobile application systems, by supporting multiple levels of consistency based on the application requirements, while savingthe mobile client energy power and reducing the consumption of the network bandwidth.The initial evaluation results show that, ABMMCCM reduces the number of uplink messages issued from the mobile client, which is assist in saving the mobile client energy and better utilizing the limited network bandwidth