Search results for: Indian adaptive thermal comfort

Authors: Awni Alkhazaleh

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Latent heat storage using Phase Change Materials (PCMs) has attracted growing attention recently in the renewable energy utilization and building energy efficiency. Paraffin (PA) of low melting temperature, which is close to human comfort temperature in the range of 24-28 °C has been considered to be used in building applications. A form-stable composite Paraffin/Expanded perlite (PA-EP) has been prepared by retaining PA into porous particles of EP. DSC (Differential scanning calorimeter) is used to measure the thermal properties of PA in the form-stable composite with/without building materials. TGA (Thermal gravimetric analysis) shows that the composite is thermally stable. SEM (Scanning electron microscope) demonstrates that the layer structure of the EP particles is uniformly absorbed by PA. The mechanical properties in flexural mode have been discussed. The thermal energy storage performance has been evaluated using a small test room (100 mm ×100 mm ×100 mm) with thickness 10 mm. The flammability test of modified sample has been discussed using a cone calorimeter. The results confirm that the form-stable composite PA has the function of reducing building energy consumption.

Keywords: flammability, latent heat storage, paraffin, plasterboard

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Authors: Rasaq Adekunle Olabomi

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More than 30% of the global building energy consumption is attributed to heating, ventilation and air-conditioning (HVAC) due to increasing urbanization and the need for more personal comfort. While heating is predominant in the temperate regions (especially during winter), comfort cooling is constantly needed in tropical regions such as Nigeria. This makes cooling a major contributor to the peak electrical load in the tropics. Meanwhile, the high solar energy availability in the tropical climate region presents a higher application potentials for solar thermal cooling systems; more so, the need for cooling mostly coincides with the solar energy availability. In addition to huge energy consumption, conventional (compressor type) air-conditioning systems mostly use refrigerants that are regarded as environmental unfriendly because of their ozone depletion potentials; this has made the alternative cooling systems to become popular in the present time. The better thermal capacity and less pumping power requirement of chilled water than chilled air has also made chilled water a preferred option over the chilled air cooling system. Radiant floor chilled water cooling is particularly is also considered suitable for spaces such as meeting room, seminar hall, auditorium, airport arrival and departure halls among others. This study did the analysis of the feasibility and energy efficiency of solar thermal chilled water for radiant flood cooling of an office apartment in a tropical climate city in Nigeria with a view to recommend its up-scaling. The analysis considered the weather parameters including available solar irradiance (kWh/m2-day) as well as the technical details of the solar thermal cooling systems to determine the feasibility. Project cost, its energy savings, emission reduction potentials and cost-to-benefits ration are used to analyze its energy efficiency as well as the viability of the cooling system. The techno-economic analysis of the proposed system, carried out using RETScreen software shows that its viability in but SWOT analysis of policy and institutional framework to promote solar energy utilization for the cooling systems shows weakness such as poor infrastructure and inadequate local capacity for technological development as major challenges.

Keywords: cooling load, absorption cooling system, coefficient of performance, radiant floor, cost saving, emission reduction

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Authors: Yong-Sung Kim, Je-Seok Shin, Ho-Jun Jo, Jin-O Kim

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Home Energy Management System (HEMS) which makes the residential consumers contribute to the demand response is attracting attention in recent years. An aim of HEMS is to minimize their electricity cost by controlling the use of their appliances according to electricity price. The use of appliances in HEMS may be affected by some conditions such as external temperature and electricity price. Therefore, the user’s usage pattern of appliances should be modeled according to the external conditions, and the resultant usage pattern is related to the user’s comfortability on use of each appliances. This paper proposes a methodology to model the usage pattern based on the historical data with the copula function. Through copula function, the usage range of each appliance can be obtained and is able to satisfy the appropriate user’s comfort according to the external conditions for next day. Within the usage range, an optimal scheduling for appliances would be conducted so as to minimize an electricity cost with considering user’s comfort. Among the home appliance, electric heater (EH) is a representative appliance which is affected by the external temperature. In this paper, an optimal scheduling algorithm for an electric heater (EH) is addressed based on the method of branch and bound. As a result, scenarios for the EH usage are obtained according to user’s comfort levels and then the residential consumer would select the best scenario. The case study shows the effects of the proposed algorithm compared with the traditional operation of the EH, and it also represents impacts of the comfort level on the scheduling result.

Keywords: load scheduling, usage pattern, user’s comfort, copula function, branch and bound, electric heater

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Authors: J. Zach, J. Hroudova, J. Brozovsky

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Thermal insulation materials based on natural fibers represent a very promising area of materials based on natural easy renewable row sources. These materials may be in terms of the properties of most competing synthetic insulations, but show somewhat higher moisture sensitivity and thermal insulation properties are strongly influenced by the density and orientation of fibers. The paper described the problem of hygrothermal behavior of thermal insulation materials based on natural plant and animal fibers. This is especially the dependence of the thermal properties of these materials on the type of fiber, bulk density, temperature, moisture and the fiber orientation.

Keywords: thermal insulating materials, hemp fibers, sheep wool fibers, thermal conductivity, moisture

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Authors: Sushil Kumar, M. Dakshina Murty

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Thermal network modelling has proven to be important tool for thermal analysis of electrical machine. This article investigates numerical thermal network model and experimental performance of a large-scale AC motor. Experimental temperatures were measured using RTD in the stator which have been compared with the numerical data. Thermal network modelling fairly predicts the temperature of various components inside the large-scale AC motor. Results of stator winding temperature is compared with experimental results which are in close agreement with accuracy of 6-10%. This method of predicting hot spots within AC motors can be readily used by the motor designers for estimating the thermal hot spots of the machine.

Keywords: AC motor, thermal network, heat transfer, modelling

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Authors: Talha Shafiq

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The traditional electricity operation in solar thermal plants is designed to operate on a single path initiating at power plant and executes at the consumer. Due to lack of energy storage facilities during this operation, a decrease in the efficiency is often observed with the power plant performance. This paper reviews the significance of energy storage in supply design and elaborates various methods that can be adopted in this regard which are equally cost effective and environmental friendly. Moreover, various parameters in thermal storage technique are also critically analyzed to clarify the pros and cons in this facility. Discussing the different thermal storage system, their technical and economical evaluation has also been reviewed.

Keywords: thermal energy storage, sensible heat storage, latent heat storage, thermochemical heat storage

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Authors: Bosiacki Mateusz, Anna Lubkowska, Dariusz Chlubek, Irena Baranowska-Bosiacka

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Exposure to cold temperatures can be considered a stressor that can lead to adaptive responses. The present study hypothesized the possibility of a positive effect of cold water exercise on mitochondrial biogenesis and muscle energy metabolism in aging rats. The purpose of this study was to evaluate the effects of cold water exercise on energy status, purine compounds, and mitochondrial biogenesis in the muscles of aging rats as indicators of the effects of cold water exercise and their usefulness in monitoring adaptive changes. The study was conducted on 64 aging rats of both sexes, 15 months old at the time of the experiment. The rats (male and female separately) were randomly assigned to the following study groups: control, sedentary animals; 5°C groups animals - training swimming in cold water at 5°C; 36°C groups - animals training swimming in water at thermal comfort temperature. The study was conducted with the approval of the Local Ethical Committee for Animal Experiments. The animals in the experiment were subjected to swimming training for 9 weeks. During the first week of the study, the duration of the first swimming training was 2 minutes (on the first day), increasing daily by 0.5 minutes up to 4 minutes on the fifth day of the first week. From the second to the eighth week, the swimming training was 4 minutes per day, five days a week. At the end of the study, forty-eight hours after the last swim training, the animals were dissected. In the skeletal muscle tissue of the thighs of the rats, we determined the concentrations of ATP, ADP, AMP, Ado (HPLC), PGC-1a protein expression (Western blot), PGC1A, Mfn1, Mfn2, Opa1, and Drp1 gene expression (qRT PCR). The study showed that swimming in water at a thermally comfortable temperature improved the energy metabolism of the aging rat muscles by increasing the metabolic rate (increase in ATP, ADP, TAN, AEC) and enhancing mitochondrial fusion (increase in mRNA expression of regulatory proteins Mfn1 and Mfn2). Cold water swimming improved muscle energy metabolism in aging rats by increasing the rate of muscle energy metabolism (increase in ATP, ADP, TAN, AEC concentrations) and enhancing mitochondrial biogenesis and dynamics (increase in the mRNA expression of proteins of fusion-regulating factors – Mfn1, Mfn2, and Opa1, and the factor regulating mitochondrial fission – Drp1). The concentration of high-energy compounds and the expression of proteins regulating mitochondrial dynamics in the muscle may be a useful indicator in monitoring adaptive changes occurring in aging muscles under the influence of exercise in cold water. It represents a short-term adaptation to changing environmental conditions and has a beneficial effect on maintaining the bioenergetic capacity of muscles in the long term. Conclusion: exercise in cold water can exert positive effects on energy metabolism, biogenesis and dynamics of mitochondria in aging rat muscles. Enhancement of mitochondrial dynamics under cold water exercise conditions can improve mitochondrial function and optimize the bioenergetic capacity of mitochondria in aging rat muscles.

Keywords: cold water immersion, adaptive responses, muscle energy metabolism, aging

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Authors: Natalie Pomerantz, Nicholas Dugan, Molly Richards, Walter Zukas

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The primary research question to be answered for Chemical/Biological (CB) protective clothing, is how to protect wearers from a range of chemical and biological threats in liquid, vapor, and aerosol form, while reducing the thermal burden. Currently, CB protective garments are hot, heavy, and wearers are limited by short work times in order to prevent heat injury. This study demonstrates how to incorporate different levels of protection on a material level and modify fabric composites such that the thermal burden is reduced to such an extent it approaches that of a standard duty uniform with no CB protection. CB protective materials are usually comprised of several fabric layers: a cover fabric with a liquid repellent coating, a protective layer which is comprised of a carbon-based sorptive material or semi-permeable membrane, and a comfort next-to-skin liner. In order to reduce thermal burden, all of these layers were laminated together to form one fabric composite which had no insulative air gap in between layers. However, the elimination of the air gap also reduced the CB protection of the fabric composite. In order to increase protection in the laminated composite, different nonwoven aerosol protective liners were added, and a super repellent coating was applied to the cover fabric, prior to lamination. Different adhesive patterns were investigated to determine the durability of the laminate with the super repellent coating, and the effect on air permeation. After evaluating the thermal properties, textile properties and protective properties of the iterations of these fabric composites, it was found that the thermal burden of these materials was greatly reduced by decreasing the thermal resistance with the elimination of the air gap between layers. While the level of protection was reduced in laminate composites, the addition of a super repellent coating increased protection towards low volatility agents without impacting thermal burden. Similarly, the addition of aerosol protective liner increased protection without reducing water vapor transport, depending on the nonwoven used, however, the air permeability was significantly decreased. The balance of all these properties and exploration of the trade space between thermal burden and protection will be discussed.

Keywords: aerosol protection, CBRNe protection, lamination, nonwovens, repellent coatings, thermal burden

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Authors: Hussein Shaman

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This study introduces an innovative design for an RF phase shifter that can maintain a consistent phase shift across a broad spectrum of frequencies. The proposed design integrates an adaptive control system into a reflective-type phase shifter, typically showing frequency-related variations. Adjusting the DC voltage according to the frequency ensures a more reliable phase shift across the frequency span of operation. In contrast, conventional frequency-dependent reflective-type phase shifters may exhibit significant fluctuations in phase shifts exceeding 60 degrees in the same bandwidth. The proposed phase shifter is configured to deliver a 90-degree operation with an expected deviation of around 15 degrees. The fabrication of the phase shifter and adaptive control circuit has been verified through experimentation, with the measured outcomes aligning with the simulation results.

Keywords: phase shifter, adaptive control, varactors, electronic circuits.

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Authors: Bouchemha Amel, Chachoui Takieddine, H. Maalem

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Automatic detection of targets in a modern communication system RADAR is based primarily on the concept of adaptive CFAR detector. To have an effective detection, we must minimize the influence of disturbances due to the clutter. The detection algorithm adapts the CFAR detection threshold which is proportional to the average power of the clutter, maintaining a constant probability of false alarm. In this article, we analyze the performance of two variants of adaptive algorithms CA-CFAR and OS-CFAR and we compare the thresholds of these detectors in the marine environment (no-Gaussian) with a Weibull distribution.

Keywords: CFAR, threshold, clutter, distribution, Weibull, detection

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Authors: Andrew Fife, Jean-Francois Esculier, Codi Ramsey, Kim Hebert-Losier

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Objectives: We aimed to identify how an evidence-based educational video influences how runners select shoes, and perceive shoe comfort, satisfaction, and performance over three months in comparison with a control video. Design: Two groups participated in a double-blind randomised controlled trial. Method: Fifty-six runners were randomly assigned to view one of two video presentations prior to purchasing new shoes for road running in speciality stores. Runners completed a survey with regards to their own shoes and one in reference to the new shoes purchased at three timepoints: before first use, onemonth post-purchase, and three-months post-purchase. Perceived shoe comfort, satisfaction, and performance were assessed using 100 mm visual analogue scales. Factors that influenced their shoe purchase were ranked in order of importance. Results: Comfort and satisfaction were not significantly different between groups and timepoints. The perceived performance of new shoes (75.6 mm) was significantly greater than own shoes (mean: 67.6 mm) before first use, but ratings returned to own-shoe levels one month later in both groups. The group receiving the evidence-based presentation reported their purchased shoes as being influenced more by the video (55.4 mm) than the control group (21.8 mm), although both chose the same brand and model as previously worn over half of the time. Runners in both groups prioritised fit, comfort, and choosing similar shoes to the ones they previously used. Conclusions: In contrast to expectations, the evidence-based educational video did not appear to influence running shoe selection, or overall perceived shoe comfort, satisfaction, or performance.

Keywords: comfort, consumer behaviour, consciousness, education, running, shoes

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Authors: R. Resmi, M. R. Baiju

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The thermal damping of a dynamic vibrating micromirror is an important factor affecting the design of MEMS based actuator systems. In the development process of new micromirror systems, assessing the extent of energy loss due to thermal damping accurately and predicting the performance of the system is very essential. In this paper, the depth of the thermal penetration layer at different eigenfrequencies and the temperature variation distributions surrounding a vibrating micromirror is analyzed. The thermal penetration depth corresponds to the thermal boundary layer in which energy is lost which is a measure of the thermal damping is found out. The energy is mainly dissipated in the thermal boundary layer and thickness of the layer is an important parameter. The detailed thermoacoustics is used to model the air domain surrounding the micromirror. The thickness of the boundary layer, temperature variations and thermal power dissipation are analyzed for a Si based torsional mode micromirror. It is found that thermal penetration depth decreases with eigenfrequency and hence operating the micromirror at higher frequencies is essential for reducing thermal damping. The temperature variations and thermal power dissipations at different eigenfrequencies are also analyzed. Both frequency-response and eigenfrequency analyses are done using COMSOL Multiphysics software.

Keywords: Eigen frequency analysis, micromirrors, thermal damping, thermoacoustic interactions

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Authors: Rim Zgueb, Noureddine Yacoubi

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The objective of this study was to investigate the thermal property of magnesium oxychloride cement (MOC) using glass powder as a substitute. Glass powder by proportion 0%, 5%, 10%, 15% and 20% of cement’s weight was added to specimens. At the end of a drying time of 28 days, thermal properties, compressive strength and bulk density of samples were determined. Thermal property is measured by Photothermal Deflection Technique by comparing the experimental of normalized amplitude and the phase curves of the photothermal signal to the corresponding theoretical ones. The findings indicate that incorporation of glass powder decreases the thermal properties of MOC.

Keywords: magnesium oxychloride cement (MOC), phototharmal deflection technique, thermal properties, Ddensity

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Authors: Satish Y. Deodhar

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Science without history is like a man without memory. The colossal history of India stores many ideas on economic ethics and public policy, which have been forgotten in the course of time. This paper is an attempt to bring to the fore contributions from ancient Indian treatises. In this context, the paper briefly summarizes alternative economic ideas such as communism, capitalism, and the holistic approach of ancient Indian writings. Thereafter, the idea of a welfare brick for an individual consisting of three dimensions -Purusharthas, Ashramas, and Varnas is discussed. Given the contours of the welfare brick, the concept of the state, its economic policies, markets, prices, interest rates, and credit are covered next. This is followed by delving into the treatment of land, property rights, guilds, and labour relations. The penultimate section summarises the economic advice offered to the head of a household in the treatise Shukranitisara. Finally, in concluding comments, the relevance of ancient Indian writings for modern times is discussed -both for pedagogy and economic policies.

Keywords: ancient Indian treatises, history of economic thought, science of political economy, Sanskrit

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Authors: Matthew D. Baffa

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Infrared thermography is a non-destructive test method used to estimate surface temperatures based on the amount of electromagnetic energy radiated by building envelope components. These surface temperatures are indicators of various qualitative building envelope deficiencies such as locations and extent of heat loss, thermal bridging, damaged or missing thermal insulation, air leakage, and moisture presence in roof, floor, and wall assemblies. Although infrared thermography is commonly used for qualitative deficiency detection in buildings, this study assesses its use as a quantitative method to estimate the overall thermal conductance value (U-value) of the exterior above-grade walls of a study home. The overall U-value of exterior above-grade walls in a home provides useful insight into the energy consumption and thermal comfort of a home. Three methodologies from the literature were employed to estimate the overall U-value by equating conductive heat loss through the exterior above-grade walls to the sum of convective and radiant heat losses of the walls. Outdoor infrared thermography field measurements of the exterior above-grade wall surface and reflective temperatures and emissivity values for various components of the exterior above-grade wall assemblies were carried out during winter months at the study home using a basic thermal imager device. The overall U-values estimated from each methodology from the literature using the recorded field measurements were compared to the nominal exterior above-grade wall overall U-value calculated from materials and dimensions detailed in architectural drawings of the study home. The nominal overall U-value was validated through calendarization and weather normalization of utility bills for the study home as well as various estimated heat loss quantities from a HOT2000 computer model of the study home and other methods. Under ideal environmental conditions, the estimated overall U-values deviated from the nominal overall U-value between ±2% to ±33%. This study suggests infrared thermography can estimate the overall U-value of exterior above-grade walls in low-rise residential homes with a fair amount of accuracy.

Keywords: emissivity, heat loss, infrared thermography, thermal conductance

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Authors: Josue Javier Martinez Flores, Jaime Alvarez Quintana

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A thermal rectifier consists of a device which can load a different heat flow which depends on the direction of that flow. That device is a thermal diode. It is well known that heat transfer in solids basically depends on the electrical, magnetic and crystalline nature of materials via electrons, magnons and phonons as thermal energy carriers respectively. In the present research, we have synthesized polycrystalline Ni-Cu alloys and identified the Curie temperatures; and we have observed that by way of secondary phase transitions, it is possible manipulate the heat conduction in solid state thermal diodes via transition temperature. In this sense, we have succeeded in developing solid state thermal diodes with a control gate through the Curie temperature via the activation and deactivation of magnons in Ni-Cu ferromagnetic alloys at room temperature. Results show thermal diodes with thermal rectification factors up to 1.5. Besides, the performance of the electrical rectifiers can be controlled by way of alloy Cu content; hence, lower Cu content alloys present enhanced thermal rectifications factors than higher ones.

Keywords: thermal rectification, Curie temperature, ferromagnetic alloys, magnons

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Authors: Gilda Santos, Rita Marques, Francisca Marques, João Ribeiro, André Fonseca, João M. Miranda, João B. L. M. Campos, Soraia F. Neves

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Every year, an unacceptable number of firefighters are seriously burned during firefighting operations, with some of them eventually losing their life. Although thermal protective clothing research and development has been searching solutions to minimize firefighters heat load and skin burns, currently commercially available solutions focus in solving isolated problems, for example, radiant heat or water-vapor resistance. Therefore, episodes of severe burns and heat strokes are still frequent. Taking this into account, a consortium composed by Portuguese entities has joined synergies to develop an innovative protective clothing system by following a procedure based on the application of numerical models to optimize the design and using a combinationof protective clothing components disposed in different layers. Recently, it has been shown that Phase Change Materials (PCMs) can contribute to the reduction of potential heat hazards in fire extinguish operations, and consequently, their incorporation into firefighting protective clothing has advantages. The greatest challenge is to integrate these materials without compromising garments ergonomics and, at the same time, accomplishing the International Standard of protective clothing for firefighters – laboratory test methods and performance requirements for wildland firefighting clothing. The incorporation of PCMs into the firefighter's protective jacket will result in the absorption of heat from the fire and consequently increase the time that the firefighter can be exposed to it. According to the project studies and developments, to favor a higher use of the PCM storage capacityand to take advantage of its high thermal inertia more efficiently, the PCM layer should be closer to the external heat source. Therefore, in this stage, to integrate PCMs in firefighting clothing, a mock-up of a vest specially designed to protect the torso (back, chest and abdomen) and to be worn over a fire-resistant jacketwas envisaged. Different configurations of PCMs, as well as multilayer approaches, were studied using suitable joining technologies such as bonding, ultrasound, and radiofrequency. Concerning firefighter’s protective clothing, it is important to balance heat protection and flame resistance with comfort parameters, namely, thermaland water-vapor resistances. The impact of the most promising solutions regarding thermal comfort was evaluated to refine the performance of the global solutions. Results obtained with experimental bench scale model and numerical simulation regarding the integration of PCMs in a vest designed as protective clothing for firefighters will be presented.

Keywords: firefighters, multilayer system, phase change material, thermal protective clothing

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Authors: Selin Öztürk Demirkiran

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Approaches towards sustainability and energy efficiency are significant topics of our era. These approaches need to be addressed across various fields and are relevant to multiple disciplines. Building facades, as the first surface encountering external weather conditions, should be considered and analyzed within this context. Current seasonal changes due to global warming and the influence on climates have highlighted the necessity for building systems to adapt to these changes, emphasizing the need for long-lasting solutions. Therefore, this study aims to examine adaptive system applications using examples from similar climatic regions and buildings of different functions, classifying them according to adaptive system criteria. It also aims to explore and evaluate the current stage of such systems in Turkey and the potential for their implementation. In this study, six building examples with different functions, including two examples for each adaptive type, were analyzed from regions with climates similar to those in Turkey, with detailed examination sheets prepared. The purpose of this study is to contribute to ongoing developments by presenting findings on current concepts and analyses and proposing a distinct approach for the characterization of these elements at the scale of Turkey. From this perspective, there is a considerable amount of literature on adaptive facade designs, and while application examples exist, adaptive approaches have been developed and partially implemented. It is expected that innovative solutions in this field will find a place in Turkey in the near future, following the increasing number of examples globally.

Keywords: adaptive facade, smart building facades, facade innovation, sustainability.

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Authors: Maatouk Khoukhi

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Nowadays the reduction of the energy consumed by buildings to achieve mainly the thermal comfort for the occupants represent the main concern for architects and building designers. The common and traditional solution to achieve this target is the design of a highly insulated envelope and reduce the opening and the transparent elements such windows. However, this will lead to the artificial lighting system to consume more energy to compensate the lack of natural lighting coming through the glazed parts of the building envelope. Therefore, a good balance between sufficient daylight and control thermal heat through the building envelope should be considered for energy saving purpose. To achieve a better indoor environment the windows size and spacing including the interior finishing and the location of the partition must be assessed accurately. Daylighting is the controlled admission of natural light into space through windows and transparent elements of the building envelope which helps create a visually stimulating and productive environment for building occupants. The main concern is not to provide enough daylight to an occupied space, but how to achieve this without any undesirable side effect. Indeed, the glare is a major problem in glazed façade buildings, and this could be reduced by using tinted windows. The main target of this research is to investigate the daylight adequacy of functional needs in old Omani Forts and how they have been designed and built to avoid glare and overheating with the appropriate window-to-floor ratio. Because more windows do not automatically result in more daylighting but that is natural light has been controlled and distributed properly throughout the space. Spaces from different Omani and Portuguese Forts under the same climate conditions are considered in order to compare the daylight illuminance levels and examine the similarities and differences in visual attributes between them. The result of this study indicates that lighting preference is not universal and people from different geographical locations are adapted to certain illuminance levels. Therefore, the standards could not be generalized for the entire world. This would be useful to practitioners who are designing to effectively address the diversity of user’s lighting levels preferences in our globally connected society.

Keywords: day lighting, energy, forts, thermal comfort

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Authors: Lima Antony

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In G. M. Hopkins’s poetics and aesthetics there is scope for a comparative study with Indian discourses on aesthetics, an area not adequately explored so far. This exploration will enrich the field of comparative study of diverse cultural expressions and their areas of similarity. A comparative study of aesthetic and religious experiences in diverse cultures will open up avenues for the discovery of similarities in self-experiences and their transcendence. Such explorations will reveal similar patterns in aesthetic and religious experiences. The present paper intends to prove this in the theories of Hopkins and Indian aesthetics. From the time of the Vedas Indian sages have believed that aesthetic enjoyment could develop into a spiritual realm. From the Natyasastra of Bharata, Indian aesthetics develops and reaches its culmination in later centuries into a consciousness of union with the mystery of the Ultimate Being, especially in Dhvanaāloka of Anandavardhana and Locana of Abhinavagupta. Dhvanyaloka elaborates the original ideas of rasa (mood or flavor) and dhvani (power of suggestion) in Indian literary theory and aesthetics. Hopkins was successful, like the ancient Indian alankarikas, in creating aesthetically superb patterns at various levels of sound and sense for which he coined the term ‘inscape’. So Hopkins’s aesthetic theory becomes suitable for transcultural comparative study with Indian aesthetics especially the dhvani theories of Anandavardhana and Abhinavagupta. Hopkins’s innovative approach to poetics and his selection of themes are quite suitable for analysis in the light of Indian literary theories. Indian philosophy views the ultimate reality called Brahman, as the 'soul,' or inner essence, of all reality. We see in Hopkins also a search for the essence of things and the chiming of their individuality with the Ultimate Being in multidimensional patterns of sound, sense and ecstatic experience. This search culminates in the realization of a synthesis of the individual self with the Ultimate Being. This is achieved through an act of surrender of the individuality of the self before the Supreme Being. Attempts to reconcile the immanent and transcendent aspects of the Ultimate Being can be traced in the Indian as well as Hopkins’s aesthetics which can contribute to greater understanding and harmony between cultures.

Keywords: Dhvani, Indian aesthetics, transcultural studies, Rasa

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Authors: Alireza Alesaadi

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Reliability analysis is a powerful method for determining the weak points of the electrical networks. In designing of electrical network, it is tried to design the most reliable network with minimal system shutting down, but it is usually associated with increasing the cost. In this paper, using adaptive genetic algorithm, a method was presented that provides the most reliable system with a certain economical cost. Finally, the proposed method is applied to a sample network and results will be analyzed.

Keywords: reliability, adaptive genetic algorithm, electrical network, communication engineering

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Authors: Hossein Kheiri, Bashir Naderi, Mohamad Reza Niknam

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In this paper we study the optimal synchronization of chaotic T-system with complete uncertain parameter. Optimal control laws and parameter estimation rules are obtained by using Hamilton-Jacobi-Bellman (HJB) technique and Lyapunov stability theorem. The derived control laws are optimal adaptive control and make the states of drive and response systems asymptotically synchronized. Numerical simulation shows the effectiveness and feasibility of the proposed method.

Keywords: Lyapunov stability, synchronization, chaos, optimal control, adaptive control

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Authors: Lu Yanru, Handojo Djati Utomo, Yin Xi Jiang, Li Xiaodong

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Insulation plays a key role in the sustainable building due to the contribution of energy consumption reduction. Without sufficient insulation, a great amount of the energy used to heat or cool a building will be lost to the outdoors. In this study, we developed a highly efficient thermal insulation paint with the incorporation of silica aerogel. Silica aerogel, with a low thermal conductivity of 0.01 W/mK, has been successfully prepared from the solid waste from the incineration plants. It has been added into water-based paints to increase its thermal insulation properties. To investigate the thermal insulation performance of silica aerogel additive, the paint samples were mixed with silica aerogel at different sizes and with various portions. The thermal conductivity, water resistance, thermal stability and adhesion strength of the samples were tested and evaluated. The thermal diffusivity measurements proved that adding silica aerogel additive could improve the thermal insulation properties of the paint significantly. Up to 5 ˚C reductions were observed after applying paints with silica aerogel additive compare to the one without it. The results showed that the developed thermal insulation paints have great potential for an application in green and sustainable building.

Keywords: silica aerogel, thermal insulation, water-based paints, water resistant

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Authors: Bessaad Taieb, Benbouali Abderrahmen

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Fuzzy controllers are a powerful tool for controlling complex processes. However, its robustness capacity remains moderately limited because it loses its property for large ranges of parametric variations. In this paper, the proposed control method is designed, based on a fuzzy adaptive controller used as a remedy for this problem. For increase the robustness of the vector control and to maintain the performance of the five-phase asynchronous machine despite the presence of disturbances (variation of rotor resistance, rotor inertia variations, sudden variations in the load etc.), by applying the method of behaviour model control (BMC). The results of simulation show that the fuzzy adaptive control provides best performance and has a more robustness as the fuzzy (FLC) and as a conventional (PI) controller.

Keywords: fuzzy adaptive control, behaviour model control, vector control, five-phase asynchronous machine

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Authors: Tamar Trop, Boris Portnov

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Public Space Lighting (PSL) of outdoor urban areas promotes comfort, defines spaces and neighborhood identities, enhances perceived safety and security, and contributes to residential satisfaction and wellbeing. However, if excessive or misdirected, PSL leads to unnecessary energy waste and increased greenhouse gas emissions, poses a non-negligible threat to the nocturnal environment, and may become a potential health hazard. At present, PSL is designed according to international, regional, and national standards, which consolidate best practice. Yet, knowledge regarding the optimal light characteristics needed for creating a perception of personal comfort and safety in densely populated residential areas, and the factors associated with this perception, is still scarce. The presented study suggests a paradigm shift in designing PSL towards a user-centered approach, which incorporates pedestrians' perspectives into the process. The study is an ongoing joint research project between China and Israel Ministries of Science and Technology. Its main objectives are to reveal inhabitants' perceptions of and preferences for PSL in different densely populated neighborhoods in China and Israel, and to develop a model that links instrumentally measured parameters of PSL (e.g., intensity, spectra and glare) with its perceived comfort and quality, while controlling for three groups of attributes: locational, temporal, and individual. To investigate measured and perceived PSL, the study employed various research methods and data collection tools, developed a location-based mobile application, and used multiple data sources, such as satellite multi-spectral night-time light imagery, census statistics, and detailed planning schemes. One of the study’s preliminary findings is that higher sense of safety in the investigated neighborhoods is not associated with higher levels of light intensity. This implies potential for energy saving in brightly illuminated residential areas. Study findings might contribute to the design of a smart and adaptive PSL strategy that enhances pedestrians’ perceived safety and comfort while reducing light pollution and energy consumption.

Keywords: energy efficiency, light pollution, public space lighting, PSL, safety perceptions

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Authors: Hamed Reza Heshmat Mohajer, Lan Ding, Mattheos Santamouris

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One of the worst environmental dangers for people who live in cities is the Urban Heat Island (UHI) impact which is anticipated to become stronger in the coming years as a result of climate change. Accordingly, the key aim of this paper is to study the interaction between the urban configuration and mitigation strategies including increasing albedo of the urban environment (reflective material), implementation of Urban Green Infrastructure (UGI) and/or a combination thereof. To analyse the microclimate models of different urban categories in the metropolis of Sydney, this study will assess meteorological parameters using a 3D model simulation tool of computational fluid dynamics (CFD) named ENVI-met. In this study, four main parameters are taken into consideration while assessing the effectiveness of UHI mitigation strategies: ambient air temperature, wind speed/direction, and outdoor thermal comfort. Layouts with present condition simulation studies from the basic model (scenario one) are taken as the benchmark. A base model is used to calculate the relative percentage variations between each scenario. The findings showed that maximum cooling potential across different urban layouts can be decreased by 2.15 °C degrees by combining high-albedo material with flora; besides layouts with open arrangements(OT1) present a highly remarkable improvement in ambient air temperature and outdoor thermal comfort when mitigation technologies applied compare to compact counterparts. Besides all layouts present a higher intensity on the maximum ambient air temperature reduction rather than the minimum ambient air temperature. On the other hand, Scenarios associated with an increase in greeneries are anticipated to have a slight cooling effect, especially on high-rise layouts.

Keywords: sustainable urban development, urban green infrastructure, high-albedo materials, heat island effect

Procedia PDF Downloads 94

Authors: K. O. Oriola, A. O. Raji, O. E. Akintola, O. T. Ismail

Abstract:

Thermal properties of roots of three improved cassava varieties (TME419, TMS 30572, and TMS 0326) were determined on samples harvested at 12, 15 and 18 Months After Planting (MAP) conditioned to moisture contents of 50, 55, 60, 65, 70% (wb). Thermal conductivity at 12, 15 and 18 MAP ranged 0.4770 W/m.K to 0.6052W/m.K; 0.4804 W/m.K to 0.5530 W/m.K and 0.3764 to 0.6102 W/m.K respectively, thermal diffusivity from 1.588 to 2.426 x 10-7m2/s; 1.290 to 2.010 x 10-7m2/s and 0.1692 to 4.464 x 10-7m2/s and specific heat capacity from 2.3626 to 3.8991 kJ/kg.K; 1.8110 to 3.9703 kJ/kgK and 1.7311 to 3.8830 kJ/kg.K respectively within the range of moisture content studied across the varieties. None of the samples over the ages studied showed similar or definite trend in variation with others across the moisture content. However, second order polynomial models fitted all the data. Age on the other hand had a significant effect on the three thermal properties studied for TME 419 but not on thermal conductivity of TMS30572 and specific heat capacity of TMS 0326. Information obtained will provide better insight into thermal processing of cassava roots into stable products.

Keywords: thermal conductivity, thermal diffusivity, specific heat capacity, moisture content, tuber age

Procedia PDF Downloads 520

Authors: Yuchen Yang, Zhenming Wang, Jun Zhu, Ning Zhao

Abstract:

An easy-to-implement and robust finite volume multi-resolution Weighted Essentially Non-Oscillatory (WENO) scheme is proposed on adaptive cartesian grids in this paper. Such a multi-resolution WENO scheme is combined with the ghost cell immersed boundary method (IBM) and wall-function technique to solve Navier-Stokes equations. Unlike the k-exact finite volume WENO schemes which involve large amounts of extra storage, repeatedly solving the matrix generated in a least-square method or the process of calculating optimal linear weights on adaptive cartesian grids, the present methodology only adds very small overhead and can be easily implemented in existing edge-based computational fluid dynamics (CFD) codes with minor modifications. Also, the linear weights of this adaptive finite volume multi-resolution WENO scheme can be any positive numbers on condition that their sum is one. It is a way of bypassing the calculation of the optimal linear weights and such a multi-resolution WENO scheme avoids dealing with the negative linear weights on adaptive cartesian grids. Some benchmark viscous problems are numerical solved to show the efficiency and good performance of this adaptive multi-resolution WENO scheme. Compared with a second-order edge-based method, the presented method can be implemented into an adaptive cartesian grid with slight modification for big Reynolds number problems.

Keywords: adaptive mesh refinement method, finite volume multi-resolution WENO scheme, immersed boundary method, wall-function technique.

Procedia PDF Downloads 148

Authors: Ochuko K. Overen, Edson L. Meyer

Abstract:

Uncontrolled heat transfer between the inner and outer space of low-cost housings through the thermal envelope result in indoor thermal discomfort. As a result, an excessive amount of energy is consumed for space heating and cooling. Thermo-optical properties are the ability of paints to reduce the rate of heat transfer through the thermal envelope. The aim of this study is to analyze the thermal performance of a low-cost house with its walls inner surface coated with transparent infrared reflective paint. The thermo-optical properties of the paint were analyzed using Scanning Electron Microscopy/ Energy Dispersive X-ray spectroscopy (SEM/EDX), Fourier Transform Infra-Red (FTIR) and thermal photographic technique. Meteorological indoor and ambient parameters such as; air temperature, relative humidity, solar radiation, wind speed and direction of a low-cost house in Golf-course settlement, South Africa were monitored. The monitoring period covers both winter and summer period before and after coating. The thermal performance of the coated walls was evaluated using time lag and decrement factor. The SEM image shows that the coat is transparent to light. The presence of Al as Al2O and other elements were revealed by the EDX spectrum. Before coating, the average decrement factor of the walls in summer was found to be 0.773 with a corresponding time lag of 1.3 hours. In winter, the average decrement factor and corresponding time lag were 0.467 and 1.6 hours, respectively. After coating, the average decrement factor and corresponding time lag were 0.533 and 2.3 hour, respectively in summer. In winter, an average decrement factor of 1.120 and corresponding time lag of 3 hours was observed. The findings show that the performance of the coats is influenced by the seasons. With a 74% reduction in decrement factor and 1.4 time lag increase in winter, it implies that the coatings have more ability to retain heat within the inner space of the house than preventing heat flow into the house. In conclusion, the results have shown that transparent infrared reflective paint has the ability to reduce the propagation of heat flux through building walls. Hence, it can serve as a remedy to the poor thermal performance of low-cost housings in South Africa.

Keywords: energy efficiency, decrement factor, low-cost housing, paints, rural development, thermal comfort, time lag

Procedia PDF Downloads 283

Authors: Mohammad Ghavami, Reza S. Dilmaghani

Abstract:

This paper presents an adaptive framework for modelling financial markets using equity risk premiums, risk free rates and volatilities. The recorded economic factors are initially used to train four adaptive filters for a certain limited period of time in the past. Once the systems are trained, the adjusted coefficients are used for modelling and prediction of an important financial market index. Two different approaches based on least mean squares (LMS) and recursive least squares (RLS) algorithms are investigated. Performance analysis of each method in terms of the mean squared error (MSE) is presented and the results are discussed. Computer simulations carried out using recorded data show MSEs of 4% and 3.4% for the next month prediction using LMS and RLS adaptive algorithms, respectively. In terms of twelve months prediction, RLS method shows a better tendency estimation compared to the LMS algorithm.

Keywords: adaptive methods, LSE, MSE, prediction of financial Markets

Procedia PDF Downloads 336