Earmuffs

Earmuffs are objects designed to cover a person's ears for hearing protection when doing the harsh work field or for warmth on the cool environment . They consist of a thermoplastic or metal head-band, that fits over the top or back of the head, and a cushion or cup at each end, to cover the external ears

Evaluación de desempeño de dos controles básicos sobre el regulador de potencia Boost: Controladores PID y difuso

The Boost converter is a DC-to-DC step-up converter that uses the characteristics of an inductive choke and a capacitor as energy storage to boost the current of the power supply and use it to inject it into the load, producing higher voltage levels at the output. This DC transformer has nonlinear dynamics due to its switching, which makes its controller design complex. In this paper, two control schemes are designed, implemented and evaluated for this power converter, a linear PID controller and a fuzzy controller. For the first case, the frequency response of the converter is considered, while the fuzzy controller is based on the converter’s behaviour with trial-and-error tuning. The results show a better performance in the fuzzy scheme, both in steady state and against transient changes.  El convertidor elevador o tipo Boost es un convertidor DC a DC elevador de tensión que usa las características de un choque inductivo y un capacitor como almacenadores de energía para elevar la corriente de la fuente de alimentación, y usarla para inyectarla a la carga, produciendo niveles de voltaje mayores en la salida. Este transformador DC tiene una dinámica no lineal debido a su conmutación, lo que hace complejo el diseño de su controlador. En este artículo se diseñan, implementan y evalúan dos esquemas de control para este convertidor de potencia, un controlador PID lineal y un controlador difuso. Para el primer caso se considera la respuesta en frecuencia del convertidor, mientras que el controlador difuso se soporta en el comportamiento del convertidor con sintonización por ensayo y error. Los resultados muestran un mejor desempeño en el esquema difuso, tanto en estado estacionario como frente a cambios transitorios. &nbsp

Dynamic performance improvement of an ultra-lift Luo DC–DC converter by using a type-2 fuzzy neural controller

© 2018 Due to the uncertainty associated with the structure and electrical elements of DC–DC converters and the nonlinear performance of these modules, designing an effective controller is highly complicated and also technically challenging. This paper employs a new control approach based on type-2 fuzzy neural controller (T2FNC) in order to improve the dynamic response of an ultra-lift Luo DC–DC converter under different operational conditions. The proposed controller can rapidly stabilize the output voltage of converter to expected values by tuning the converter switching duty cycle. This controller can tackle the uncertainties associated with the structure of converters, measured control signals and measuring devices. Moreover, a new intelligent method based on firefly algorithm is applied to tune the parameters of T2FNC. In order to demonstrate the effectiveness of the proposed control approach, the proposed controller is compared to PI and fuzzy controllers under different operational conditions. Results validate efficiency of proposed T2FNC

Alternative fuel from vegetable oils and animal fats

This study investigated the properties of processing vegetable and animal fat to be used as alternative fuel. The vegetable oil processing industry comprises the abstraction and treating of oils and fats from vegetable sources. Vegetable oils and fats are principally used for human consumption but are also used in animal feed, for medicinal purposes, and certain technical applications. In contrast triglycerides, vegetable waxes lack glycerin in their structure. Although many plant parts may yield oil, in commercial practice, oil is extracted primarily from seeds, for many developing countries, the concept of employing vegetable oils as sources for diesel fuels can be attractive. Often the culture of the appropriate plant is well established, the oil extraction well developed, and handling and storage well defined. Yields per hectare of tropical crops such as palm and coconut oils far exceed the yields of vegetable oils in temperate zones. Also, the production of most tropical vegetable oils has positive energy. A rendering process is performed to remove excess fat from animal carcasses and then turned into oil. Thus, to obtain refined oil, there is process from crude palm oil that involves removal of the products of hydrolysis and oxidation or abstraction process of oil from the palm kernels. After refining, the oil may be split (fractionated) into liquid and solid phases by thermo-mechanical means such as controlled cooling, crystallization, and filtering, the later oil is competing successfully with the more expensive groundnut, corn, and sunflower oils

High efficiency smart voltage regulating module for green mobile computing

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.In this thesis a design for a smart high efficiency voltage regulating module capable of supplying the core of modern microprocessors incorporating dynamic voltage and frequency scaling (DVS) capability is accomplished using a RISC based microcontroller to facilitate all the functions required to control, protect, and supply the core with the required variable operating voltage as set by the DVS management system. Normally voltage regulating modules provide maximum power efficiency at designed peak load, and the efficiency falls off as the load moves towards lesser values. A mathematical model has been derived for the main converter and small signal analysis has been performed in order to determine system operation stability and select a control scheme that would improve converter operation response to transients and not requiring intense computational power to realize. A Simulation model was built using Matlab/Simulink and after experimenting with tuned PID controller and fuzzy logic controllers, a simple fuzzy logic control scheme was selected to control the pulse width modulated converter and several methods were devised to reduce the requirements for computational power making the whole system operation realizable using a low power RISC based microcontroller. The same microcontroller provides circuit adaptations operation in addition to providing protection to load in terms of over voltage and over current protection. A novel circuit technique and operation control scheme enables the designed module to selectively change some of the circuit elements in the main pulse width modulated buck converter so as to improve efficiency over a wider range of loads. In case of very light loads as the case when the device goes into standby, sleep or hibernation mode, a secondary converter starts operating and the main converter stops. The secondary converter adapts a different operation scheme using switched capacitor technique which provides high efficiency at low load currents. A fuzzy logic control scheme was chosen for the main converter for its lighter computational power requirement promoting implementation using ultra low power embedded controllers. Passive and active components were carefully selected to augment operational efficiency. These aspects enabled the designed voltage regulating module to operate with efficiency improvement in off peak load region in the range of 3% to 5%. At low loads as the case when the computer system goes to standby or sleep mode, the efficiency improvent is better than 13% which will have noticeable contribution in extending battery run time thus contributing to lowering the carbon footprint of human consumption

Konflik pengambilan tanah Orang Asli: kajian kes di Johor dan Selangor

Orang Asli merupakan golongan minoriti yang terdapat di Semenanjung Malaysia. Sistem Torrens yang diamalkan oleh Malaysia melalui Kanun Tanah Negara 1965 hanya memberi kepentingan terhadap tanah yang didaftarkan di Pejabat Pendaftaran Tanah, manakala tanah saka Orang Asli yang diwarisi dari generasi ke generasi tidak termasuk dalam sistem pendaftaran. Objektif kajian ini adalah (1) Mengenalpasti konflik yang berlaku akibat daripada pengambilan tanah Orang Asli yang terlibat, (2) Menganalisis kesan pengambilan tanah terhadap masyarakat Orang Asli yang terlibat dan (3) Menjelaskan usaha penyelesaian konflik pengambilan tanah Orang Asli yang terlibat. Bagi mencapai objektif kajian ini, kaedah kualitatif telah digunakan melalui kaedah temubual semi struktur. Temubual ini telah dijalankan ke atas lima belas responden utama daripada pihak berkepentingan iaitu enam orang Tok Batin dan Penolong Batin bagi setiap kampung yang terlibat, dua pegawai daripada pejabat tanah Negeri Johor dan Selangor, tiga pegawai daripada Jabatan Kemajuan Orang Asli , seorang pegawai daripada Suruhanjaya Hak Asasi Malaysia (SUHAKAM), seorang wakil badan bukan kerajaan iaitu Persatuan Orang Asli Semenanjung Malaysia , dan seorang ahli akademik. Hasil kajian mendapati bahawa terdapat konflik di antara masyarakat Orang Asli, konflik di antara Orang Asli dan Pihak Berkuasa serta konflik di antara agensi kerajaan Negeri dan Persekutuan. Kesan pengambilan tanah dapat dilihat melalui kesan terhadap sosiobudaya, persekitaran dan ekonomi masyarakat Orang Asli yang terlibat. Kaedah penyelesaian bagi pengambilan tanah Orang Asli yang terlibat adalah melalui rundingan, bayaran pampasan, menggunakan saluran mahkamah, Dasar Pemberi Milikan Tanah Orang Asli oleh Jabatan Kemajuan Orang Asli dan Inkuiri Nasional oleh Suruhanjaya Hak Asasi Kemanusiaan Malaysia

Measurements, Models, Systems and Design

531 s.