534 research outputs found
Helio tracker: P.V. integrated shading device
No full textThe EU is committed to reducing the energy used and Co2 produced by 2050. Every component plays an important part in building an energy efficient building. This thesis looks at P.V. integrated shading devices.Shading devices are designed to block the excess solar radiation coming into the building to reduce the energy load of a building. This surface can be utilized to generate electricity by adding P.V. panels. P.V. panels are more efficient if they track the sun’s movement to increase the amount of solar radiation falling on the surface. The existing solar tracking devices fail due to multiple gears and the load of the panel on the rotational device.To tackle this problem heliotropic plants were studied. Heliotropic plants follow the sun’s movement to receive more solar radiation for photosynthesis. The internal mechanisms and forces of a sunflower (heliotropic plant) that cause this movement was analysed through an experiment and digital image correlation. The analysis showed that the sunflower’s stem utilizes water to expand and contract the sides of the stem in a diurnal pattern so that the stem can track the sun. This expansion and contraction curves the stem to move it 14 degrees which is sufficient to increase the solar radiation on the plant. This property of expansion and contraction was taken forward to design a sun tracking P.V. integrated shading to produce more energy. The expansion and contraction of the device were enabled by utilizing segments that were moved by piezo electric actuators. The Piezo electric actuator uses the energy generated from the P.V. panel and converts it to mechanical energy which enables the rotation of the device.To find the angle for rotation a simulation was made to find the angle at which the P.V. panel produces the most energy and the angle at which the shading device reduces the load on the heating or cooling device. The device is designed to track the change in the sun's altitude as this rotation produces the most energy for a P.V. panel and a shading device. The device responds to the change in altitude four times a year as this corresponds to the seasons to which the shading device rotates. There were two simulations made for the energy saved by the P.V. integrated shading device. The first simulation was for the Netherlands, factoring the energy saved by the shading device and the energy losses by the mechanical parts the device produces 196kW/ year and reduces the heating and cooling load by 16%. In Abu Dhabi, the same device produces 777kW/ year which reduces the cooling load by 15%.<br/
Effects of molecular hydrogen on low-intensity UV photochemistry of germanosilicate glasses
No full textThe one-quantum photo-reactions of oxygen deficient centers (GODC) in H2 loaded germanosilicate preforms and fibers are studied using time-resolved photo-luminescence and ESR spectroscopy
Effects of Ge concentration on one-quantum UV photo-reactions of oxygen deficient centers in germanosilicate glasses
No full textThe effects of Ge concentration, spectroscopic and photochemical inhomogeneity on GODC photochemistry in germanosilicate fibers and preforms are established and their mechanisms are discussed
UV laser-induced current in germanosilicate fibres with built in electrodes
No full textThe nature of photocurrents is studied in germano-silicate single-mode fibres with built in electrodes. It is shown that irradiation by excimer KrF laser pulses at electric field intensities up to 1.6 MV cm-1 there causes a charge formation and transfer in the core of the fibre and the injection of photoelectrons from metal electrodes to the fibre cladding. Both effects facilitate the flow of electric current through the sample. The dependences of the photocurrent on the electric field strength, the energy density in the loser pulse, the fibre temperature, and the impurity hydrogen in the fibre core are obtained. <br/
One photon and two photon process in photo-decomposition of germanium oxygen deficient centres
No full textUV photon-induced transformation of germanium oxygen deficient centres (GODC) in germanium-doped silica glass have been studied using photocurrent measurements, absorption and fluorescence bleaching. It has been identified that the photocurrent are generated via a two photon effect. Evidence have been found suggesting that the UV photon-induced destruction of GODCs is achieved via two reaction pathways, a single photon pathway and a two photon pathway. The process is discussed
Effect of electric field on one-quantum photodecay of oxygen-deficient centers in germanosilicate fibers
No full textThe effect of a strong electric field (up to 106 V/cm) on one-quantum UV photoexcitation and photodecomposition of germanium oxygen deficient centers (GODC) in twin-hole germanosilicate fibers with internal wire electrodes is reported. The fiber has been irradiated with the UV light of a deuterium lamp and triplet photoluminescence of GODC has been used to monitor the kinetics of its photodecay. Applying such an electric field did not affect the spectral characteristics of GODC but increased the rate of their one-quantum photodecomposition, while direct photoionization and charge separation did not take place. We have also shown that this effect is caused by the suppression of secondary photoinduced recombination processes of intermediates, rather than by acceleration of primary photodecomposition of GODC
Direct observation of ultraviolet laser induced photocurrent in oxygen deficient silica and germanosilicate glasses
No full textUV laser induced ionization of silicon oxygen deficient centers (SODC) in silica glasses and germanium oxygen deficient centers (GODC) in germanosilicate glasses has been studied by direct displacement photocurrent measurements. For both SODC and GODC the two‐photon (two‐step) nature of photoionization has been established. The cross sections of transitions from first excited to upper (ionizable) states were estimated as σ12 = 6×10−18 cm2 for SODC and (0.5–1.0)×10−19 cm2 for GODC. The effect of pulse‐to‐pulse degradation of the photocurrent signal caused by the screening effect is applied to estimate the lifetimes and ranges of the free carriers. The conclusion was drawn, that ionized SODC and GODC play the key role for free charge trapping.<br/
Book Review on Puspayurvedah - A unique contribution of Prof. P.V. Sharma
No full text"Puspayurvedah" authored by Prof. P.V. Sharma, is a scholarly collection of the use of flowers in the Ayurvedic system of medicine. Despite being a specialized subject, traditional Indian medicine heavily relies on the therapeutic qualities, historical importance, and medicinal qualities of diverse flowers. The author painstakingly catalogs a vast variety of flowers using the botanical features and medicinal properties found in traditional Ayurvedic texts. The book offers academicians and clinicians, a thorough knowledge of traditional uses of flowers. "Puspayurvedah" is not only a useful academic resource but also a useful guide for anyone who wants to use floral remedies in Ayurvedic therapy because of its practical formulations and applications. The book is notable for its comprehensiveness and depth of knowledge
From “Made in China” to “Created in China”: Development of ICT-enabled medical device and system for rural China
No full textHealth problems are a major concern for rural Chinese people. One of the causes is shortages of medical resources, such as medical equipment and skilled medical staff. Information and Communication Technology (ICT) is usually seen as a useful tool, by which medical resources in urban areas can be accessed for rural areas. Design and development of ICT-enabled Medical device and system for Rural China (DIMRC) is therefore considered to be a key approach of the Chinese central government in the development of rural healthcare. In practice, however, the gap between ideal ICT-enabled medical devices and systems and what is currently available in rural markets is still huge. Both the quantity and quality of existing ICT-enabled medical applications fall short of meeting the requirements of patients and doctors. To bridge this gap, the Chinese government has been encouraging local Chinese Research and Development (R&D) teams (from local companies and universities) to design and develop ICT-enabled medical devices and systems with appropriate innovations, suitable specifically for China. This is a part of China’s recent product development strategy, dubbed “Created in China”. This strategy encourages the local development of products in China by national brands, and increasingly replaces the “Made in China” strategy. There are several steps to be taken to reduce the gap between the ideal ICT-enabled medical devices and systems and those currently available in the rural markets. This PhD study focuses on one aspect: exploring what design competences of Chinese R&D teams should be improved and how to improve them. Three methods are used in this study: literature analysis, practice-based research, and interviews. The results of this thesis have revealed three issues that demand attention if the design competences of Chinese R&D teams are to be augmented: (1) R&D teams should have a deep understanding of China’s culture with reference to DIMRC; (2) the teams should have more knowledge about identification of design factors for DIMRC; and (3) the teams should have more knowledge to apply existing design methodologies to DIMRC. The results of this thesis were utilised to develop a new framework for DIMRC. In addition, an education module for integration into Chinese biomedical engineering education has been created. Finally both results were evaluated by one Chinese biomedical engineering professor and one senior biomedical engineer from a Chinese medical device company.Design EngineeringIndustrial Design Engineerin
Meanings of Materials
No full textThis book is about meanings we attribute to materials of the objects around us. Materials convey meanings: they look traditional, they express luxury, they are associated with factories, or they conjure up one’s childhood. How do materials obtain these meanings? How do they interact with other elements of product design in expressing certain meanings? How can designers systematically incorporate meaning considerations into their materials selection processes? This book presents the concept of meanings of materials and has made a start in making this concept more actionable in design thinking.Design EngineeringIndustrial Design Engineerin
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