Litar penuai tenaga hibrid mikro untuk aplikasi bioperubatan

Penggunaan penuai tenaga sebagai bekalan kuasa mendapat perhatian tinggi terutamanya untuk peranti berskala mikro. Ianya memanfaatkan sumber tenaga ambien untuk menghasilkan tenaga elektrik. Kajian yang mendalam telah dilakukan bagi memperolehi penuai tenaga dengan kecekapan dan kepekaan yang tinggi. Tiga sumber tenaga digunakan sebagai masukan iaitu tenaga haba, getaran dan Frekuensi Radio (RF). Masukan tenaga haba adalah dalam bentuk voltan DC manakala masukan getaran dan RF adalah dalam bentuk voltan AC. Kesemua masukan ini masing-masing ditetapkan pada nilai 0.02 V, 0.5 V dan -20 dBm. Frekuensi operasi yang digunakan bagi masukan getaran adalah 10 Hz manakala bagi masukan RF adalah 915 MHz. Litar penerus gelombang penuh digunakan bagi menukarkan isyarat getaran AC kepada DC. Sementara itu, litar pendarab voltan dibina dengan mengaplikasikan teknik modulasi substrat bagi menggandakan voltan masukan. Kesemua litar penuai tenaga tunggal ini digabungkan menggunakan litar penambah voltan untuk membentuk satu sistem penuai tenaga hibrid yang lengkap. Litar-litar penuai tenaga ini dibina dan disimulasi menggunakan perisian PSPICE dengan menyambungkan perintang beban 1 MΩ. Litar lengkap penuai tenaga dengan masukan hibrid berjaya mencapai voltan keluaran lebih kurang 2.12 V dan sesuai digunakan sebagai alternatif bekalan kuasa kepada aplikasi peranti bioperubatan. Peranti tersebut adalah Peranti Pemantau Kesihatan yang memerlukan bekalam masukan minimum 1.7 V

Best practice in questioning child witnesses in Malaysia / Amirul Irfan Ahmad Badaruddin, Farah Nasuha Sudarman and Fatin Syafira Ahmad Zulkifli

This research analysed the weaknesses of the current practise on questioning techniques used for child witnesses and to give recommendation with the intention to increase the reliability and the quality of evidence given by a child witness. The First chapter discussed the research objectives, methodology, scope and limitations and problem statement. In addition, all the necessary conceptual features are introduced to ensure the readers to understand about the research. The second chapter explained on the psychological state and capabilities of a child that needs to be understand before questioning a child witness. In the third chapter, the researchers pointed out other relevant factors that may affect the accuracy of evidence given by a child witness. The fourth chapter discussed on the findings based on several semi-structured interviews. Our research concludes with recommendations in guiding to better techniques in questioning a child witness and other methods that may help in increasing the accuracy of evidence given by children

ULTRA LOW POWER HYBRID MICRO ENERGY HARVESTER USING RF, THERMAL AND VIBRATION FOR BIOMEDICAL DEVICES

The objective of this research is to design ultra-low power Hybrid Micro Energy Harvester (HMEH) circuit using hybrid inputs of radio frequency (RF), thermal and vibration for biomedical devices. In the HMEH architecture, three input sources (RF, thermal and vibration) are combined in parallel to solve the limitation issue of a single source energy harvester and to improve the system performance. Energy will be scavenged from the human body for thermal and vibration sources by converting directly temperature difference and human movement to electrical energy. The inputs are set to 0.02V and 0.5V for thermal and vibration respectively with the frequency of 1 kHz. Meanwhile, RF source is absorbed from radio wave propagation in our surrounding. For this work, the frequency is set to 915MHz and the output voltages for input ranges of-20dBm to 5dBm are recorded. The performance analysis of the HMEH is divided into two; thermal and vibration harvester circuit and RF harvester circuit. These proposed HMEH circuits are modeled, designed and simulated using PSPICE software. Vibration produces AC input and will be converted to DC using a rectifier. A comparator is used to compare the two sources (thermal and vibration) and boost converter is proposed to step-up these small input sources. Meanwhile, due to RF large frequency, the voltage multiplier is practical for both rectify and step up the input instead of the boost converter. LC resonant network is used to amplify low ambient input of RF passively before it goes to 4–stages voltage multiplier. The proposed HMEH able to achieve the output ranges of 2.0 to 4.0V with 1MΩ load. The results obtained in this research work shows that the proposed design able to produce sufficient voltage for biomedical application requirement which lies between 2.0–4.0 V from the ambient input of 0.02 to 0.5V for thermal and vibration while-9dBm for RF signal