Search results for: passive solar architecture

Authors: Yulia Eka Putrie, Widjaja Martokusumo

Abstract:

The development of architecture today indicates that an architectural object often does not represent one single identity only. One architectural object could represents layers of multiple identities of an increasingly complex society. Mosque architecture for example, is mainly associated with one religious identity; that mosque architecture serves as the representation of Islamic identity. However, on many occasions, mosque architecture also serves as the representation of other motives, such as political, social, even individual identity. In normal circumstances, these layers of identities are not always seen or realized by common people outside the community. They are only represented implicitly in some symbolic forms, activities, and events. On the other hand, in specific circumstances, these kinds of identities were represented explicitly in mosque architecture. This paper is a part of an initial research on the representation of socio-political identities in Nahdliyyin mosques in East Java, Indonesia. Nahdliyyin mosques were chosen as the object of research because of its significance in Indonesian socio-political context, because majority of Indonesian muslims are culturally associated with Nahdlatul Ulama (NU) with its aswaja doctrine. Some frictions in mosque ownership and management between Nahdliyyin and other islamic school of thoughts, has resulted in preventive efforts, where some of the efforts are related to the representation of their identity in their mosque architecture. The research is a field research that took place in Malang, East Java. Malang is one of main cities in East Java; a cultural and regional basis of NU and Nahdliyyin people. Formal analysis were conducted in ten large Nahdliyyin mosques in Malang. Some structured and in-depth interviews were also held to explore the motives of identity representation in some architectural aspects of the mosques. The result of this initial study indicates that there are layers of identities which were manifested in the studied mosques. These layers of identities in Nahdliyyin mosques were based on the same main values, but represented through various formal expressions. Furthermore, the study also brings the deeper understanding on socio-political context of mosques in Nahdliyyin culture.

Keywords: Nahdliyyin mosque architecture, layers of identities, representation, Nahdlatul Ulama

Procedia PDF Downloads 519

Authors: Mohammad Moonesun, Ehsan Asadi Asrami, Julia Bodnarchuk

Abstract:

In the case of Solar Autonomous Underwater Vehicle, which uses photovoltaic panels to provide its required power, due to limitation of energy, accurate estimation of resistance and energy has major sensitivity. In this work, hydrodynamic calculations by numerical method for a solar autonomous underwater vehicle equipped by two 50 W photovoltaic panels has been studied. To evaluate the required power and energy, hull hydrodynamic resistance in several velocities should be taken into account. To do this assessment, the ANSYS FLUENT 18 applied as Computational Fluid Dynamics (CFD) tool that solves Reynolds Average Navier Stokes (RANS) equations around AUV hull, and K-ω SST is used as turbulence model. To validate of solution method and modeling approach, the model of Myring submarine that it’s experimental data was available, is simulated. There is good agreement between numerical and experimental results. Also, these results showed that the K-ω SST Turbulence model is an ideal method to simulate the AUV motion in low velocities.

Keywords: underwater vehicle, hydrodynamic resistance, numerical modelling, CFD, RANS

Procedia PDF Downloads 205

Authors: Toktam mehrabani

Abstract:

Textiles, fashion, and architecture, though seemingly disparate fields, share a deep and evolving relationship. This paper explores the intersection of these disciplines, examining how the tactile, structural, and aesthetic qualities of textiles have influenced both fashion and architecture over time. By investigating historical and contemporary examples, this paper seeks to unravel the ways in which textiles and fashion have not only shaped architectural design but have also acted as a bridge between functionality, art, and human experience in the built environment.Textiles have been integral to human culture since the dawn of civilization. Their presence transcends mere functionality, serving as a medium for artistic expression, cultural identity, and social commentary. Fashion, derived from textiles, has long been associated with personal identity and societal trends, while architecture reflects human needs, environmental context, and cultural values. This paper posits that the relationship between textiles, fashion, and architecture is more interconnected than often perceived, with each influencing and inspiring the other across time. Textiles in Architectural Design: From ancient draperies in temples to tapestries in castles, textiles have adorned structures, softening rigid spaces and adding layers of warmth and luxury. Fabric screens and curtains have also served functional purposes, such as controlling light, acoustics, and temperature. Fashion as Architectural Expression: Renaissance and Baroque fashion used exaggerated forms, corsetry, and layers to mirror the grandiosity of architectural styles of the time. Clothing acted as wearable architecture, with structured garments mirroring the strong lines and curves of buildings..Structural Textiles in Architecture: In the 21st century, textiles are no longer just decorative; they have become integral to architectural innovation. Materials like tensile fabrics and smart textiles are used in creating flexible, lightweight structures. Iconic examples include Frei Otto’s work with tensile membranes, seen in the Munich Olympic Stadium.Technological advancements have drastically transformed the relationship between textiles, fashion, and architecture. Digital tools like 3D printing and laser cutting allow designers in both fields to push the limits of form and structure. Smart textiles that react to environmental stimuli are being explored for use in both wearable technology and adaptable architecture, such as facades that change in response to weather conditions. Textiles, fashion, and architecture are inextricably linked through their shared exploration of form, structure, and expression. This interdisciplinary relationship continues to evolve, driven by technological advancements and a growing emphasis on sustainability. As fashion becomes more architectural in its construction and architecture more fluid in its forms, the lines between these disciplines blur, offering new possibilities for creativity and functionality in both wearable and built environments.

Keywords: textiles in architecture, fashion and architecture, textile architecture, structural textiles, wearable architecture, architectural fashion

Procedia PDF Downloads 31

Authors: Sahba Paktinat, Afshin Salajeghe, Mir Ali Seyyedi, Yousef Rastegari

Abstract:

Service Oriented Architecture (SOA) allows modeling of dynamic interaction between incongruous providers, which enables governing the development of complex applications. However, implementation of SOA comes with some challenges, including its adaptability and robustness. Dynamism is inherent to the nature of service-based applications and of their running environment. These factors lead to necessity for dynamic adaptation. In this paper, we try to describe basics and main structure of SOA adaptation process with a conceptual view to this issue. In this survey, we will review the relevant adaptation approaches. This paper allows studying how different approaches deal with service oriented architecture adaptation life-cycle and provides basic guidelines for their analysis, evaluation and comparison.

Keywords: context-aware, dynamic adaptation, quality of services, service oriented architecture, service based application

Procedia PDF Downloads 455

Authors: P. Sathyakala, G. Sai Sundara Krishnan

Abstract:

The objective of this paper is to derive an exergy model for a solar water heater with honey comb structure in order to identify the element which has larger irreversibility in the system. This will help us in finding the means to reduce the wasted work potential so that the overall efficiency of the system can be improved by finding the ways to reduce those wastages.

Keywords: exergy, energy balance, entropy balance, work potential, degradation, honey comb, flat plate collector

Procedia PDF Downloads 478

Authors: Dimitra Sygkridou, Dimitrios Karageorgopoulos, Elias Stathatos, Evangelos Vitoratos

Abstract:

Transparent nickel doped cobalt sulfide was fabricated on a SnO2:F electrode and tested as an efficient electrocatalyst and as an alternative to the expensive platinum counter electrode. In order to investigate how this electrode could affect the electrical characteristics of a dye-sensitized solar cell, we manufactured cells with the same TiO2 photoanode sensitized with dye (N719) and employing the same quasi-solid electrolyte, altering only the counter electrode used. The cells were electrically and electrochemically characterized and it was observed that the ones with the Ni doped CoS2 outperformed the efficiency of the cells with the Pt counter electrode (3.76% and 3.44% respectively). Particularly, the higher efficiency of the cells with the Ni doped CoS2 counter electrode (CE) is mainly because of the enhanced photocurrent density which is attributed to the enhanced electrocatalytic ability of the CE and the low charge transfer resistance at the CE/electrolyte interface.

Keywords: nickel doped cobalt sulfide, counter electrodes, dye-sensitized solar cells, quasi-solid state electrolyte, hybrid organic-inorganic materials

Procedia PDF Downloads 760

Authors: Azzeddine Abdelalim, Fatiha Rogti

Abstract:

The degradation phenomenon in polymer solar cells (PCSs) has not been clearly explained yet. In fact, there are many causes that show up and influence these cells in a variety of ways. Also, there has been a growing concern over this degradation in the photovoltaic community. One of the main variables deciding PSCs photovoltaic output is defect states. In this research, devices modeling is carried out to analyze the multiple effects of degradation by applying high defect states (HDS) on ideal PSCs, mainly poly(3-hexylthiophene) (P3HT) absorber layer. Besides, a comparative study is conducted between P3HT and other PSCs by a simulation program called Solar Cell Capacitance Simulator (SCAPS). The adjustments to the defect parameters in several absorber layers explain the effect of HDS on the total output properties of PSCs. The performance parameters for HDS, quantum efficiency, and energy band were therefore examined. This research attempts to explain the degradation process of PSCs and the causes of their low efficiency. It was found that the defects often affect PSCs performance, but defect states have a little effect on output when the defect level is less than 1014cm-3, which gives similar performance values with P3HT cells when these defects is about 1019cm-3. The high defect states can cause up to 11% relative reduction in conversion efficiency of ideal P3HT. In the center of the band gap, defect states become more noxious. This approach is for one of the degradation processes potential of PSCs especially that use fullerene derivative acceptors.

Keywords: degradation, high defect states, polymer solar cells, SCAPS-1D

Procedia PDF Downloads 91

Authors: Huiqiang Yang, Domingo Santana

Abstract:

Reducing parasitic power consumption of concentrating solar power plants is the main challenge to increase the overall efficiency, particularly for molten salt tower technology. One of the most effective approaches to reduce the parasitic power consumption is to implement a natural draft dry cooling system instead of the standard utilized mechanical draft dry cooling system. In this paper, a thermo-economic analysis of a natural draft direct cooling system was performed based on a 100MWe commercial scale molten salt power plant. In this configuration with a natural draft direct cooling system, the exhaust steam from steam turbine flows directly to the heat exchanger bundles inside the natural draft dry cooling tower, which eliminates the power consumption of circulation pumps or fans, although the cooling tower shadows a portion of the heliostat field. The simulation results also show that compared to a mechanical draft cooling system the annual solar field efficiency is decreased by about 0.2% due to the shadow, which is equal to a reduction of approximately 13% of the solar field area. As a contrast, reducing the solar field size by 13% in purpose in a molten salt power plant with a natural draft drying cooling system actually will lead to a reduction of levelized cost of electricity (LCOE) by about 4.06% without interfering the power generated.

Keywords: molten salt power tower, natural draft dry cooling, parasitic power consumption, commercial scale

Procedia PDF Downloads 168

Authors: Shuwen Hu, Yuancheng Lou, Dongxu Ji

Abstract:

Photovoltaic (PV) power generation, as one of the most commercialized methods to utilize solar power, can only convert a limited range of solar spectrum into electricity, whereas the majority of the solar energy is dissipated as heat. To address this problem, thermoelectric (TE) module is often integrated with the concentrated PV module for waste heat recovery and regeneration. In this research, a feasibility analysis is conducted for the tandem concentrated photovoltaic-thermoelectric (CPV-TE) hybrid system considering various operational parameters as well as TE material properties. Furthermore, the power output density of the CPV-TE hybrid system is maximized by selecting the optimal TE material with application of a systematic assessment methodology. In the feasibility analysis, CPV-TE is found to be more advantageous than sole CPV system except under high optical concentration ratio with low cold side convective coefficient. It is also shown that the effects of the TE material properties, including Seebeck coefficient, thermal conductivity, and electrical resistivity, on the feasibility of CPV-TE are interacted with each other and might have opposite effect on the system performance under different operational conditions. In addition, the optimal TE material selected by the proposed assessment methodology can improve the system power output density by 227 W/m2 under highly concentrated solar irradiance hence broaden the feasible range of CPV-TE considering optical concentration ratio.

Keywords: feasibility analysis, material assessment methodology, photovoltaic waste heat recovery, tandem photovoltaic-thermoelectric

Procedia PDF Downloads 72

Authors: Sabrina Rahman

Abstract:

The Mosque is Islam’s most symbolic structure, as well as the expression of collective identity. From the explicit words of our Prophet, 'The earth has been created for me as a masjid and a place of purity, and whatever man from my Ummah finds himself in need of prayer, let him pray' (anywhere)! it is obvious that a devout Muslim does not require a defined space or structure for divine worship since the whole earth is his prayer house. Yet we see that from time immemorial man throughout the Muslim world has painstakingly erected innumerable mosques. However, mosque design spans time, crosses boundaries, and expresses cultures. It is a cultural manifestation as much as one based on a regional building tradition or a certain interpretation of religion. The trend to express physical signs of religion is not new. Physical forms seem to convey symbolic messages. However, in recent times physical forms of mosque architecture are dominantly demising from mosque architecture projects in Bangladesh. Dome & minaret, the most prominent symbol of the mosque, is replacing by contextual and contemporary improvisation rather than subcontinental mosque architecture practice of early fellows. Thus the recent mosque projects of the last 15 years established the contemporary architectural realm in their design. Contextually, spiritual lighting, the serenity of space, tranquility of outdoor spaces, the texture of materials is widely establishing a new genre of Muslim prayer space. A case study based research will lead to specify its significant factors of modernism. Based on the findings, the paper presents evidence of recent projects as well as a guideline for the future image of contemporary Mosque architecture in Bangladesh.

Keywords: contemporary architecture, modernism, prayer space, symbolism

Procedia PDF Downloads 121

Authors: Oluropo Stephen Ilesanmi, Oluwole Ayodele Alejo

Abstract:

Architectural education, beyond training the students to become architects, impacts in them the appreciation of the responsibilities relating to public health, safety, and welfare. Architecture is no longer a personal philosophical or aesthetic pursuit by individuals, rather, it has to consider everyday needs of the people and use technology to give a liveable environment. In the present age, architectural education must have to grapple with the recent integration of technology, in particular, facilities offered by information and communication technology. Electronic technologies have moved architecture from the drawing board to cyberspace. The world is now a global village in which new information and methods are easily and quickly available to people at different poles of the globe. It is the position of this paper that in order to remain relevant in the ever-competing forces within the building industry, architectural education must show the impetus to continue to draw from technological advancements associated with the use of computers.

Keywords: architecture, education, communication, information, technology

Procedia PDF Downloads 210

Authors: Carlos A. Domínguez Torres, Antonio Domínguez Delgado

Abstract:

In this work we study the thermodynamic behavior of some ventilated facades under summer operating conditions in Southern Spain. Under these climatic conditions, indoor comfort implies a high energetic demand due to high temperatures that usually are reached in this season in the considered geographical area. The aim of this work is to determine if during summer operating conditions in Southern Spain, ventilated façades provide some energy saving compared to the non-ventilated façades and to deduce their behavior patterns in terms of energy efficiency. The modeling of the air flow in the channel has been performed by using Navier-Stokes equations for thermodynamic flows. Numerical simulations have been carried out with a 2D Finite Element approach. This way, we analyze the behavior of ventilated façades under different weather conditions as variable wind, variable temperature and different levels of solar irradiation. CFD computations show that the combined effect of the shading of the external wall and the ventilation by the natural convection into the air gap achieve a reduction of the heat load during the summer period. This reduction has been evaluated by comparing the thermodynamic performances of two ventilated and two unventilated façades with the same geometry and thermophysical characteristics.

Keywords: passive cooling, ventilated façades, energy-efficient building, CFD, FEM

Procedia PDF Downloads 355

Authors: Zahzouh Zoubir

Abstract:

The widespread adoption of photovoltaic panel systems for global electricity generation is a prominent trend. Algeria, demonstrating steadfast commitment to strategic development and innovative projects for harnessing solar energy, emerges as a pioneering force in the field. Heat and radiation, being fundamental factors in any solar system, are currently subject to comprehensive studies aiming to discern their genuine impact on crucial elements within photovoltaic systems. This endeavor is particularly pertinent given that solar module performance is exclusively assessed under meticulously defined Standard Test Conditions (STC). Nevertheless, when deployed outdoors, solar modules exhibit efficiencies distinct from those observed under STC due to the influence of diverse environmental factors. This discrepancy introduces ambiguity in performance determination, especially when surpassing test conditions. This article centers on the performance monitoring of an Algerian photovoltaic project, specifically the Oued El Keberite power (OKP) plant boasting a 15 megawatt capacity, situated in the town of Souk Ahras in eastern Algeria. The study elucidates the behavior of a subfield within this facility throughout the year, encompassing various conditions beyond the STC framework. To ensure the optimal efficiency of solar panels, this study integrates crucial factors, drawing on an authentic technical sheet from the measurement station of the OKP photovoltaic plant. Numerical modeling and simulation of a sub-field of the photovoltaic station were conducted using MATLAB Simulink. The findings underscore how radiation intensity and temperature, whether low or high, impact the short-circuit current, open-circuit voltage; fill factor, and overall efficiency of the photovoltaic system.

Keywords: performance monitoring, photovoltaic system, numerical modeling, radiation intensity

Procedia PDF Downloads 69

Authors: Eman I. Raslan, Haitham S. Hamza, Reda A. El-Khoribi

Abstract:

Fiber-Wireless (FiWi) networks are a promising candidate for future broadband access networks. These networks combine the optical network as the back end where different passive optical network (PON) technologies are realized and the wireless network as the front end where different wireless technologies are adopted, e.g. LTE, WiMAX, Wi-Fi, and Wireless Mesh Networks (WMNs). The convergence of both optical and wireless technologies requires designing architectures with robust efficient and effective bandwidth allocation schemes. Different bandwidth allocation algorithms have been proposed in FiWi networks aiming to enhance the different segments of FiWi networks including wireless and optical subnetworks. In this survey, we focus on the differentiating between the different bandwidth allocation algorithms according to their enhancement segment of FiWi networks. We classify these techniques into wireless, optical and Hybrid bandwidth allocation techniques.

Keywords: fiber-wireless (FiWi), dynamic bandwidth allocation (DBA), passive optical networks (PON), media access control (MAC)

Procedia PDF Downloads 531

Authors: W. N. L. Mahadi, S. N. Syed Zin, W. A. R. Othman, N. A. Mohd Rasyid, N. Jusoh

Abstract:

Public concerns on Extremely Low Frequency (ELF) Electromagnetic Field (EMF) exposure have been elongated since the last few decades. Electrical substations and high tension rooms (HT room) in commercial buildings were among the contributing factors emanating ELF magnetic fields. This paper discussed various shielding methods conventionally used in mitigating the ELF exposure. Nevertheless, the standard methods were found to be impractical and incapable of meeting currents shielding demands. In response to that, remarkable researches were conducted in effort to invent novel methods which is more convenient and efficient such as magnetic aqueous shielding or paint, textiles and papers shielding. A mitigation method using magnetic aqueous substrate in shielding application was proposed in this paper for further investigation. using Manganese Zinc Ferrite (Mn0.4Zn0.6Fe2O4). The magnetic field and flux distribution inside the aqueous magnetic material are evaluated to optimize shielding against ELF-EMF exposure, as to mitigate its exposure.

Keywords: ELF shielding, magnetic aqueous substrate, shielding effectiveness, passive shielding, magnetic material

Procedia PDF Downloads 531

Authors: Thirayu Jumsai Na Ayudhya

Abstract:

The study of what architecture means to people in their everyday lives inadequately addresses the contextualized and holistic theoretical framework. This article succinctly presents theoretical framework obtained from the comparative study of how people experience the everyday architecture in three different contexts including 1) Bangkok CBD, 2) Phuket island old-town, and 3) Nan province old-town. The way people make sense of the everyday architecture can be addressed in four super-ordinate themes; (1) building in urban (text), (2) building in (text), (3) building in human (text), (4) and building in time (text). In this article, these super-ordinate themes were verified whether they recur in three studied-contexts. In each studied-context, the participants were divided into two groups, 1) local people, 2) visitors. Participants were asked to take photographs of the everyday architecture during the everyday routine and to participate the elicit-interview with photographs produced by themselves. Interpretative phenomenological analysis (IPA) was adopted to interpret elicit-interview data. Sub-themes emerging in each studied-context were brought into the cross-comparison among three studied- contexts. It is found that four super-ordinate themes recur with additional distinctive sub-themes. Further studies in other different contexts, such as socio-political, economic, cultural differences, are recommended to complete the theoretical framework.

Keywords: sense of place, the everyday architecture, architectural experience, the everyday

Procedia PDF Downloads 157

Authors: Lawal Alkasim, Clement M. Gonah, Zainab S. Aliyu

Abstract:

This work is focus on recovering silicon form photovoltaic cells and repurposing it toward the use in glass, ceramics or glass ceramics as it is made up of silicon material. Silicon is the main back-bone and responsible for the thermodynamic properties of glass, ceramics and glass ceramics materials. Antireflection silicon is soluble in hot alkali. Successfully the recovered material composed of silicon and silicon nitride of the A.R, with a small amount of silver, Aluminuim, lead & copper in the sunshine of crystalline/non-crystalline silicon solar cell. Aquaregia is used to remove the silver, Aluminium, lead & copper. The recovered material treated with hot alkali highly concentrated to produce sodium silicate, which is an alkali silicate glass (water glass). This type of glass is produced through chemical process, unlike other glasses that are produced through physical process of melting and non-crystalline solidification. It has showed a property of being alkali silicate glass from its solubility in water and insoluble in alcohol. The XRF analysis shows the presence of sodium silicate.

Keywords: unrecyclable solar PV, crystalline silicon, hot conc. alkali, sodium silicate

Procedia PDF Downloads 101

Authors: Corinna Barraco, Ornella Salimbene

Abstract:

This research involves the Ethiopian locality of Jeldi (North Africa), an area particularly affected by water shortage and in which the pumping and treatment of drinking water are extremely sensitive issues. The study aims to develop and apply low-cost tools for the design of solar water pumping and water purification systems in a not developed country. Consequently, two technical tools have been implemented in Excel i) Solar photovoltaic Pumping (Spv-P) ii) Water treatment (Wt). The Spv-P tool was applied to the existing well (depth 110 [m], dynamic water level 90 [m], static water level 53 [m], well yield 0.1728 [m³h⁻¹]) in the Jeldi area, where estimated water demand is about 50 [m3d-1]. Through the application of the tool, it was designed the water extraction system of the well, obtaining the number of pumps and solar panels necessary for water pumping from the well of Jeldi. Instead, the second tool Wt has been applied in the subsequent phase of extracted water treatment. According to the chemical-physical parameters of the water, Wt returns as output the type of purification treatment(s) necessary to potable the extracted water. In the case of the well of Jeldi, the tool identified a high criticality regarding the turbidity parameter (12 [NTU] vs 5 [NTU]), and a medium criticality regarding the exceeding limits of sodium concentration (234 [mg/L Na⁺] vs 200 [mg/L Na⁺]) and ammonia (0.64 [mg/L NH³-N] vs 0.5 [mg/L NH³-N]). To complete these tools, two specific manuals are provided for the users. The joint use of the two tools would help reduce problems related to access to water resources compared to the current situation and represents a simplified solution for the design of pumping systems and analysis of purification treatments to be performed in undeveloped countries.

Keywords: drinking water, Ethiopia, treatments, water pumping

Procedia PDF Downloads 156

Authors: Timothy J. Considine, Edward J. M. Manderson

Abstract:

This paper develops an econometric forecasting system of energy demand coupled with engineering-economic models of energy supply. The framework is used to quantify the impact of state-level renewable portfolio standards (RPSs) achieved predominately with solar generation on electricity rates, electricity consumption, and environmental quality. We perform the analysis using Arizona’s RPS as a case study. We forecast energy demand in Arizona out to 2035, and find by this time the state will require an additional 35 million MWh of electricity generation. If Arizona implements its RPS when supplying this electricity demand, we find there will be a substantial increase in electricity rates (relative to a business-as-usual scenario of reliance on gas-fired generation). Extending the current regime of tax credits can greatly reduce this increase, at the taxpayers’ expense. We find that by 2025 Arizona’s RPS will implicitly abate carbon dioxide emissions at a cost between $101 and $135 per metric ton, and by 2035 abatement costs are between $64 and $112 per metric ton (depending on the future evolution of nature gas prices).

Keywords: electricity demand, renewable portfolio standard, solar, carbon dioxide

Procedia PDF Downloads 485

Authors: Meriem Boukais, B. Dennai, A. Ould- Abbas

Abstract:

The efficiency of SiGe solar cells might be improved by a wide-band-gap window layer. In this work we were simulated using the one dimensional simulation program called analysis of microelectronic and photonic structures (AMPS-1D). In the modeling, the thickness of silicon window was varied from 80 to 150 nm. The rest of layer’s thicknesses were kept constant, by varying thickness of window layer the simulated device performance was demonstrate in the form of current-voltage (I-V) characteristics and quantum efficiency (QE).

Keywords: modeling, SiGe, AMPS-1D, quantum efficiency, conversion, efficiency

Procedia PDF Downloads 721

Authors: Mrinalini Amritkar, Disha Patil, Swapna Kulkarni, Sukratu Barve, Suresh Gosavi

Abstract:

Micro-mixers play an important role in the lab-on-a-chip applications and micro total analysis systems to acquire the correct level of mixing for any given process. The mixing process can be classified as active or passive according to the use of external energy. Literature of microfluidics reports that most of the work is done on the models of steady laminar flow; however, the study of unsteady laminar flow is an active area of research at present. There are wide applications of this, out of which, we consider nanoparticle synthesis in micro-mixers. In this work, we have developed a model for unsteady flow to study the mixing performance of a passive micro mixer for reactants used for such synthesis. The model is developed in Finite Volume Method (FVM)-based software, OpenFOAM. The model is tested by carrying out the simulations at Re of 0.5. Mixing performance of the micro-mixer is investigated using simulated concentration values of mixed species across the width of the micro-mixer and calculating the variance across a line profile. Experimental validation is done by passing dyes through a Y shape micro-mixer fabricated using polydimethylsiloxane (PDMS) polymer and comparing variances with the simulated ones. Gold nanoparticles are later synthesized through the micro-mixer and collected at two different times leading to significantly different size distributions. These times match with the time scales over which reactant concentrations vary as obtained from simulations. Our simulations could thus be used to create design aids for passive micro-mixers used in nanoparticle synthesis.

Keywords: Lab-on-chip, LOC, micro-mixer, OpenFOAM, PDMS

Procedia PDF Downloads 161

Authors: Boukais Meriem, B. Dennai, A. Ould-Abbas

Abstract:

The efficiency of SiGe solar cells might be improved by a wide-band-gap window layer. In this work we were simulated using the one dimensional simulation program called analysis of microelectronic and photonic structures (AMPS-1D). In the simulation, the thickness of silicon window was varied from 80 to 150 nm. The rest of layer’s thicknesses were kept constant, by varying thickness of window layer the simulated device performance was demonstrate in the form of current-voltage (I-V) characteristics and quantum efficiency (QE).

Keywords: SiGe, AMPS-1D, simulation, conversion, efficiency, quantum efficiency

Procedia PDF Downloads 805

Authors: Joel Y. Y. Loh, Geoffrey A. Ozin, Charles A. Mims, Nazir P. Kherani

Abstract:

A major goal in the emerging field of solar fuels is to realize an ‘artificial leaf’ – a material that converts light energy in the form of solar photons into chemical energy – using CO2 as a feedstock to generate useful chemical species. Enabling this technology will allow the greenhouse gas, CO2, emitted from energy and manufacturing production exhaust streams to be converted into valuable solar fuels or chemical products. Indium Oxide (In2O3) with surface hydroxyl (OH) groups have been shown to reduce CO2 in the presence of H2 to CO with a reaction rate of 15 μmol gcat−1 h−1. The likely mechanism is via a Frustrated Lewis Pair sites heterolytically splitting H2 to be absorbed and form protonic and hydric sites that can dissociate CO2. In this study, we investigate the dependence of oxygen composition of In2O3 on the CO2 reduction rate. In2O3-x films on quartz fiber paper were DC sputtered with an Indium target and varying O2/Ar plasma mixture. OH surface groups were then introduced by immersing the In2O3-x samples in KOH. We show that hydroxylated In2O3-x reduces more CO2 than non-hydroxylated groups and that a hydroxylated and higher O2/Ar ratio sputtered In2O3-x has a higher reaction rate of 45 μmol gcat-1 h-1. We show by electrical resistivity-temperature curves that H2 is adsorbed onto the surface of In2O3 whereas CO2 itself does not affect the indium oxide surface. We also present activation and ionization energy levels of the hydroxylated In2O3-x under vacuum, CO2 and H2 atmosphere conditions.

Keywords: solar fuels, photocatalysis, indium oxide nanoparticles, carbon dioxide

Procedia PDF Downloads 240

Authors: Slamet Subiyantoro, Mulyanto

Abstract:

Revealing the structure and symbolism meaning of the walisanga’s mosque arts in Java is very important to explain the philosophy of religious foundation which is a manifestation of the norms/ value system and behavior of the Javanese Islam society that support the culture. This research's aims are also to find the structure pattern of walisanga’s mosque and its symbolic meaning in the context of Javanese Islam society. In order to obtain the research objectives, the research were done in several walisanga’s mosques in Java using anthropological approach which is focused on its interpretation and semiotic analysis. The data were collected through interviews with key informants who well informed about the shape and symbolism of walisanga’s mosques in Java. The observation technique is done through visiting walisanga’s mosques to see directly about its structure/ architecture. In completing the information of comprehensive result of the research, it is also used documents and archives as well as any other source which is analyzed to deepen the discussion in answering the problems research. The flow of analysis is done using an interactive model through stages of data collection, data reduction, data presentation and verification. The analysis is done continuously in a cycle system to draw valid conclusions. The research result indicates that the structure/architecture of walisanga’s mosque in Java is structured/built up vertically as well as horizontally. Its structure/architecture is correlated to each other which is having a sacred meaning that is a process represents the mystical belief such as sangkan paraning dumadi and manuggaling kawula gusti.

Keywords: Walisanga’s mosques, Java, structure and architecture, meaning

Procedia PDF Downloads 369

Authors: Piyush Sharma, Laltu Chandra, P. S. Ghoshdastidar, Rajiv Shekhar

Abstract:

Metals processing operations such as melting and heat treatment of metals are energy-intensive, requiring temperatures greater than 500oC. The desired temperature in these industrial furnaces is attained by circulating electrically-heated air. In most of these furnaces, electricity produced from captive coal-based thermal power plants is used. Solar thermal energy could be a viable heat source in these furnaces. A retrofitted solar convective furnace (SCF) concept, which uses solar thermal generated hot air, has been proposed. Critical to the success of a SCF is the design of an open volumetric air receiver (OVAR), which can heat air in excess of 800oC. The OVAR is placed on top of a tower and receives concentrated solar radiation from a heliostat field. Absorbers, mixer assembly, and the return air flow chamber (RAFC) are the major components of an OVAR. The absorber is a porous structure that transfers heat from concentrated solar radiation to ambient air, referred to as primary air. The mixer ensures uniform air temperature at the receiver exit. Flow of the relatively cooler return air in the RAFC ensures that the absorbers do not fail by overheating. In an earlier publication, the detailed design basis, fabrication, and characterization of a 2 kWth open volumetric air receiver (OVAR) based laboratory solar air tower simulator was presented. Development of an experimentally-validated, CFD based mathematical model which can ultimately be used for the design and scale-up of an OVAR has been the major objective of this investigation. In contrast to the published literature, where flow and heat transfer have been modeled primarily in a single absorber module, the present study has modeled the entire receiver assembly, including the RAFC. Flow and heat transfer calculations have been carried out in ANSYS using the LTNE model. The complex return air flow pattern in the RAFC requires complicated meshes and is computational and time intensive. Hence a simple, realistic 1-D mathematical model, which circumvents the need for carrying out detailed flow and heat transfer calculations, has also been proposed. Several important results have emerged from this investigation. Circumferential electrical heating of absorbers can mimic frontal heating by concentrated solar radiation reasonably well in testing and characterizing the performance of an OVAR. Circumferential heating, therefore, obviates the need for expensive high solar concentration simulators. Predictions suggest that the ratio of power on aperture (POA) and mass flow rate of air (MFR) is a normalizing parameter for characterizing the thermal performance of an OVAR. Increasing POA/MFR increases the maximum temperature of air, but decreases the thermal efficiency of an OVAR. Predictions of the 1-D mathematical are within 5% of ANSYS predictions and computation time is reduced from ~ 5 hours to a few seconds.

Keywords: absorbers, mixer assembly, open volumetric air receiver, return air flow chamber, solar thermal energy

Procedia PDF Downloads 197

Authors: C. S. Seema, P. R. Prince

Abstract:

The characterization of spatio-temporal inhomogeneities occurring in the ionospheric F₂ layer is remarkable since these variations are direct consequences of electrodynamical coupling between magnetosphere and solar events. The temporal and spatial variations of the F₂ layer, which occur with a period of several days or even years, mainly owe to geomagnetic and meteorological activities. The hourly F₂ layer critical frequency (foF2) over 23rd solar cycle (1996-2008) of three ionosonde stations (Wakkanai, Kokunbunji, and Okinawa) in northern hemisphere, which falls within same longitudinal span, is analyzed using continuous wavelet techniques. Morlet wavelet is used to transform continuous time series data of foF2 to a two dimensional time-frequency space, quantifying the time evolution of the oscillatory modes. The presence of significant time patterns (periodicities) at a particular time period and the time location of each periodicity are detected from the two-dimensional representation of the wavelet power, in the plane of scale and period of the time series. The mean strength of each periodicity over the entire period of analysis is studied using global wavelet spectrum. The quasi biennial, annual, semiannual, 27 day, diurnal and 12 hour variations of foF2 are clearly evident in the wavelet power spectra in all the three stations. Critical frequency oscillations with multi-day periods (2-3 days and 9 days in the low latitude station, 6-7 days in all stations and 15 days in mid-high latitude station) are also superimposed over large time scaled variations.

Keywords: continuous wavelet analysis, critical frequency, ionosphere, solar cycle

Procedia PDF Downloads 220

Authors: Aušra Černauskienė

Abstract:

The heritage of modern architecture is closely related to the materiality and technology used to implement the buildings. Concrete is one of the most ubiquitous post-war building materials with enormous aesthetic and structural potential that architects have creatively used for everyday buildings and exceptional architectural objects that have survived. Concrete's material, structural, and architectural development over the post-war years has produced a remarkably rich and diverse typology of buildings, for implementation of which unique handicraft skills and industrialized novelties were used. Nonetheless, in the opinion of the public, concrete architecture is often treated as ugly and obsolete, and in Lithuania, it also has negative associations with the scarcity of the Soviet era. Moreover, aesthetic non-appreciation is not the only challenge that concrete architecture meets. It also no longer meets the needs of contemporary requirements: buildings are of poor energy class, have little potential for transformation, and have an obsolete surrounding environment. Thus, as a young heritage, concrete architecture is not yet sufficiently appreciated by society and heritage specialists, as it takes a short time to rethink what they mean from a historical perspective. However, concrete architecture is considered ambiguous but has its character and specificity that needs to be carefully studied in terms of cultural heritage to avoid the risk of poor renovation or even demolition, which has increasingly risen in recent decades in Lithuania. For example, several valuable pieces of post-war concrete architecture, such as the Banga restaurant and the Summer Stage in Palanga, were demolished without understanding their cultural value. Many unique concrete structures and raw concrete surfaces were painted or plastered, paying little attention to the appearance of authentic material. Furthermore, it raises a discussion on how to preserve buildings of different typologies: for example, innovative public buildings in their aesthetic, spatial solutions, and mass housing areas built using precast concrete panels. It is evident that the most traditional preservation strategy, conservation, is not the only option for preserving post-war concrete architecture, and more options should be considered. The first step in choosing the right strategy in each case is an appropriate assessment of the cultural significance. For this reason, an evaluation matrix for post-war concrete architecture is proposed. In one direction, an analysis of different typological groups of buildings is suggested, with the designation of ownership rights; in the other direction – the analysis of traditional value aspects such as aesthetic, technological, and relevant for modern architecture such as social, economic, and sustainability factors. By examining these parameters together, three relevant scenarios for preserving post-war concrete architecture were distinguished: conservation, renovation, and reuse, and they are revealed using examples of concrete architecture in Lithuania.

Keywords: modern heritage, value aspects, typology, conservation, upgrade, reuse

Procedia PDF Downloads 143

Authors: Rasaq Adekunle Olabomi

Abstract:

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

Procedia PDF Downloads 27

Authors: V. E. Selaule, R. M. Schoeman H. C. Z. Pienaar

Abstract:

Research has shown that solar energy is a renewable energy resource with the most potential when compared to other renewable energy resources in South Africa. There are many makes of Photovoltaic (PV) panels on the market and it is difficult to assess which to use. PV panel manufacturers use Standard Test Conditions (STC) to rate their PV panels. STC conditions are different from the actual operating environmental conditions were the PV panels are used. This paper describes a practical method to determine the most cost effective available PV panel. The method shows that PV panel manufacturer STC ratings cannot be used to select a cost effective PV panel.

Keywords: PV orientation, PV panel, PV STC, Solar energy

Procedia PDF Downloads 473

Authors: Sreejith Gopinath, Aspen Olmsted

Abstract:

This paper is based on our previous work that proposed a risk-transference-based architecture for healthcare systems to store sensitive data outside the system boundary, rendering the system unattractive to would-be bad actors. This architecture also allows a compromised system to be abandoned and a new system instance spun up in place to ensure business continuity without paying a ransom or engaging with a bad actor. This paper delves into the details of various attacks we simulated against the prototype system. In the paper, we discuss at length the time and computational costs associated with storing and retrieving data in the prototype system, abandoning a compromised system, and setting up a new instance with existing data. Lastly, we simulate some analytical workloads over the data stored in our specialized data storage system and discuss the time and computational costs associated with running analytics over data in a specialized storage system outside the system boundary. In summary, this paper discusses the total costs of data storage, access, and analytics incurred with the proposed architecture.

Keywords: cybersecurity, healthcare, ransomware, resilience, risk transference

Procedia PDF Downloads 133