Search results for: low energy residence

Authors: Wu Xingchun, Chen Xi

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Nowadays, China's building energy consumption constitutes 25% of the total energy consumption, half of which was caused by air conditioning in both summer and winter. The ventilation system in Chinese traditional residence, which is totally passive and environmentally friendly, works effectively to create comfortable indoor environment. The research on the ventilation system in Chinese traditional residence can provide advancements to architecture design and energy savings to the society. Through field investigation, case analysis, strategy proposing and other methods, it comes out that the location and layout, the structure system and the design of atrium are the most important elements for a good ventilation system. Taking every factor into consideration, techniques are deployed extensively such as the organization of draught, the design of the thermal pressure ventilation system and the application of modern materials. With the enlightenment of the ventilation system in Chinese traditional residence, we can take effective measures to achieve low energy consumption and sustainable architecture.

Keywords: ventilation system, chinese traditional residence, energy consumption, sustainable architecture

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Authors: Y. Jin, N. Zhang, X. Luo, W. Zhang

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China with annual increasing 0.5-0.6 billion squares city residence has brought in enormous energy consumption by HVAC facilities and other appliances. In this regard, governments and researchers are encouraging renewable energy like solar energy, geothermal energy using in houses. However, high cost of equipment and low energy conversion result in a very low acceptable to residents. So what’s the equilibrium point of eco-feedback to reach economic benefit and thermal comfort? That is the main question should be answered. In this paper, the objective is an on-site solar PV and heater house, which has been evaluated as a low energy building. Since HVAC system is considered as main energy consumption equipment, the residence with 24-hour monitoring system set to measure temperature, wind velocity and energy in-out value with no HVAC system for one month of summer and winter. Thermal comfort time period will be analyzed and confirmed; then the air-conditioner will be started within thermal discomfort time for the following one summer and winter month. The same data will be recorded to calculate the average energy consumption monthly for a purpose of whole day thermal comfort. Finally, two analysis work will be done: 1) Original building thermal simulation by computer at design stage with actual measured temperature after construction will be contrastive analyzed; 2) The cost of renewable energy facilities and power consumption converted to cost efficient rate to assess the feasibility of renewable energy input for residence. The results of the experiment showed that a certain deviation exists between actual measured data and simulated one for human thermal comfort, especially in summer period. Moreover, the cost-effectiveness is high for a house in targeting city Guilin now with at least 11 years of cost-covering. The conclusion proves that an eco-feedback of a low energy residence is never only consideration of its energy net value, but also the cost efficiency that is the critical factor to push renewable energy acceptable by the public.

Keywords: cost efficiency, eco-feedback, low energy residence, thermal comfort

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Authors: Huashan Tai, Chien-Hui Lung

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Nowadays people use massive fossil fuels which not only cause environmental impacts and global climate change, but also cause the depletion of non-renewable energy such as coal and oil. Bioenergy is currently the most widely used renewable energy, and agricultural waste is one of the main raw materials for bioenergy. In this study, we use orange peel residue, which is easier to collect from agricultural waste to produce bio-coal by torrefaction. The orange peel residue (with 25 to 30% moisture) was treated by torrefaction, and the experiments were conducted with initial temperature at room temperature (approximately at 25° C), with heating rates of 10, 30, and 50°C / min, with terminal temperatures at 150, 200, 250, 300, 350℃, and with residence time of 10, 20, and 30 minutes. The results revealed that the heating value, ash content and energy densification ratio of the solid products after torrefaction are in direct proportion to terminal temperatures and residence time, and are inversely proportional to heating rates. The moisture content, solid mass yield, energy yield, and volumetric energy density of the solid products after torrefaction are inversely proportional to terminal temperatures and residence time, and are in direct proportion to heating rates. In conclusion, we found that the heating values of the solid products were 1.3 times higher than those of the raw orange peels before torrefaction, and the volumetric energy densities were increased by 1.45 times under operating parameters with terminal temperature at 250°C, residence time of 10 minutes, and heating rate of 10°C / min of torrefaction. The results indicated that the residue of orange peel treated by torrefaction improved its energy density and fuel properties, and became more suitable for bio-fuel applications.

Keywords: biomass energy, orange, torrefaction

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Authors: Arsenio Jose Mindu

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The concern to carry out a study related to Energy Efficiency arose based on the various debates in international television networks and not only, but also in several forums of national debates. The concept of Energy Efficiency is not yet widely disseminated and /or taken into account in terms of energy consumption, not only at the domestic level but also at the industrial level in Mozambique. In the context of the energy audit, the time during which each of the appliances is connected to the voltage source, the time during which they are in standby mode was recorded on a spreadsheet basis. Based on these data, daily and monthly consumption was calculated. In order to have more accurate information on the daily levels of daily consumption, the electricity consumption was read every hour of the day (from 5:00 am to 11:00 pm), since after 23:00 the energy consumption remains constant. For ten days. Based on the daily energy consumption and the maximum consumption power, the design of the photovoltaic system for the residence was made. With the implementation of the photovoltaic system in order to guarantee energy efficiency, there was a significant reduction in the use of electricity from the public grid, increasing from approximately 17 kwh per day to around 11 kwh, thus achieving an energy efficiency of 67.4 %. That is to say, there was a reduction not only in terms of the amount of energy consumed but also of the monthly expenses with electricity, having increased from around 2,500,00Mt (2,500 meticais) to around 800Mt per month.

Keywords: energy efficiency, photovoltaic system, residential sector, Mozambique

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Authors: Motlatso Rampedi

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Nigeria has the fifth highest Total Fertility Rate in Sub-Saharan Africa at 5.5 children born to a woman. Some demographic research has found that there is an association between region of residence and fertility in Nigeria, with the Northern regions pertaining to high fertility and the Southern regions pertaining to low fertility levels. Even so, little attention has been given to understanding the effect of region of residence on fertility. Instead, a significant amount of research has been conducted on exploring the proximate determinants of fertility in Nigeria. The objective of this study was to test whether there is an association between region of residence and fertility in Nigeria. Using a sample size of 38 948 women aged 15-49 derived from the 2013 NDHS and the Poisson regression model for analysis, the study has found that region of residence has a significant effect on fertility. Moreover, the ANOVA test has shown that there is a socioeconomic disparity by region of residence in Nigeria. The Northern regions of Nigeria have shown to have higher levels of fertility as compared to the Southern regions. Therefore, while proximate determinants of fertility and socio-demographic characteristics of women are important, region of residence remains one of the fundamental determinants of fertility. Given these findings, it is recommended that government should not exhaust its resources or focus its fertility reduction policies and programmes at entire populations but target specific regions where fertility is most prevalent.

Keywords: high fertility, region, socioeconomic disparity, socio-demographic characteristics

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Authors: Ebrahim Tilahun, Erkan Sahinkaya, Bariş Calli̇

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Raw biogas is a valuable renewable energy source however it usually needs removal of the impurities. The presence of hydrogen sulfide (H2S) in the biogas has detrimental corrosion effects on the cogeneration units. Removal of H2S from the biogas can therefore significantly improve the biogas quality. In this work, a conventional bioscrubber (CBS), and a dense membrane bioscrubber (DMBS) were comparatively evaluated in terms of H2S removal efficiency (RE), CH4 enrichment and alkaline consumption at gas residence times ranging from 5 to 20 min. Both bioscrubbers were fed with a synthetic biogas containing H2S (1%), CO2 (39%) and CH4 (60%). The results show that high RE (98%) was obtained in the DMBS when gas residence time was 20 min, whereas slightly lower CO2 RE was observed. While in CBS system the outlet H2S concentration was always lower than 250 ppmv, and its H2S RE remained higher than 98% regardless of the gas residence time, although the high alkaline consumption and frequent absorbent replacement limited its cost-effectiveness. The result also indicates that in DMBS when the gas residence time increased to 20 min, the CH4 content in the treated biogas enriched upto 80%. However, while operating the CBS unit the CH4 content of the raw biogas (60%) decreased by three fold. The lower CH4 content in CBS was probably caused by extreme dilution of biogas with air (N2 and O2). According to the results obtained here the DMBS system is a robust and effective biotechnology in comparison with CBS. Hence, DMBS has a better potential for real scale applications.

Keywords: biogas, bioscrubber, desulfurization, PDMS membrane

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Authors: Hua-Shan Tai, Yu-Ting Zeng

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In modern and industrial society, enormous amounts of sludge from various of industries are constantly produced; currently, most of the sludge are treated by landfill and incineration. However, both treatments are not ideal because of the limited land for landfill and the secondary pollution caused by incineration. Consequently, treating industrial sludge appropriately has become an urgent issue of environmental protection. In order to solve the problem of the massive sludge, this study uses textile sludge which is the major source of waste sludge in Taiwan as raw material for torrefaction treatments. To investigate the feasibility of producing biofuels from textile sludge by torrefaction, the experiments were conducted with temperatures at 150, 200, 250, 300, and 350°C, with heating rates of 15, 20, 25 and 30°C/min, and with residence time of 30 and 60 minutes. The results revealed that the mass yields after torrefaction were approximately in the range of 54.9 to 93.4%. The energy densification ratios were approximately in the range of 0.84 to 1.10, and the energy yields were approximately in the range of 45.9 to 98.3%. The volumetric densities were approximately in the range of 0.78 to 1.14, and the volumetric energy densities were approximately in the range of 0.65 to 1.18. To sum up, the optimum energy yield (98.3%) can be reached with terminal temperature at 150 °C, heating rate of 20°C/min, and residence time of 30 minutes, and the mass yield, energy densification ratio as well as volumetric energy density were 92.2%, 1.07, and 1.15, respectively. These results indicated that the solid products after torrefaction are easy to preserve, which not only enhance the quality of the product, but also achieve the purpose of developing the material into fuel.

Keywords: biofuel, biomass energy, textile sludge, torrefaction

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Authors: Molshree A. Sharma

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As a result of globalization, it is increasingly common for people to live in different parts of the world. However there is a corresponding rise of international family law issues and competing jurisdictions. The Hague Convention on the Civil Aspects of Child Abduction is a multilateral treaty that provides an expeditious method to return a child to their country of habitual residence when ‘internationally abducted’ by a parent from one member country to another. Specifically, the Convention provides a protocol for expeditious return of the child to their habitual residence unless there is a valid exception, the most common being that return would result in an intolerable situation or cause grave risk of harm to the child. This paper analyzes case law from various signatory countries including the United States, highlighting the differences in interpretation of key terms under the Convention, as well as case law in non-Hague signatory countries, with a focus on India and the Middle East.

Keywords: best interest of the child, grave risk of harm, habitual residence, well-settled

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Authors: Usman Dahiru, Faisal Saleem, Kui Zhang, Adam Harvey

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Volatile organic compounds (VOCs) are atmospheric contaminants predominantly derived from petroleum spills, solvent usage, agricultural processes, automobile, and chemical processing industries, which can be detrimental to the environment and human health. Environmental problems such as the formation of photochemical smog, organic aerosols, and global warming are associated with VOC emissions. Research showed a clear relationship between VOC emissions and cancer. In recent years, stricter emission regulations, especially in industrialized countries, have been put in place around the world to restrict VOC emissions. Non-thermal plasmas (NTPs) are a promising technology for reducing VOC emissions by converting them into less toxic/environmentally friendly species. The dielectric barrier discharge (DBD) plasma is of interest due to its flexibility, moderate capital cost, and ease of operation under ambient conditions. In this study, a dielectric barrier discharge (DBD) reactor has been developed for the decomposition of cyclohexane (as a VOC model compound) using nitrogen, dry, and humidified air carrier gases. The effect of specific input energy (1.2-3.0 kJ/L), residence time (1.2-2.3 s) and concentration (220-520 ppm) were investigated. It was demonstrated that the removal efficiency of cyclohexane increased with increasing plasma power and residence time. The removal of cyclohexane decreased with increasing cyclohexane inlet concentration at fixed plasma power and residence time. The decomposition products included H₂, CO₂, H₂O, lower hydrocarbons (C₁-C₅) and solid residue. The highest removal efficiency (98.2%) was observed at specific input energy of 3.0 kJ/L and a residence time of 2.3 s in humidified air plasma. The effect of humidity was investigated to determine whether it could reduce the formation of solid residue in the DBD reactor. It was observed that the solid residue completely disappeared in humidified air plasma. Furthermore, the presence of OH radicals due to humidification not only increased the removal efficiency of cyclohexane but also improves product selectivity. This work demonstrates that cyclohexane can be converted to smaller molecules by a dielectric barrier discharge (DBD) non-thermal plasma reactor by varying plasma power (SIE), residence time, reactor configuration, and carrier gas.

Keywords: cyclohexane, dielectric barrier discharge reactor, non-thermal plasma, removal efficiency

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Authors: Reneiloe Seodigeng, John Kabuba, Hilary Rutto, Tumisang Seodigeng

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Urine diversion toilets have become popular as a means of solving the challenges in sanitation. As a result, the source-separated urine must be adequately treated so that it can be disposed of safely and valuable struvite can be extracted for use as fertilizer. In this study, synthetic urine was prepared, and struvite crystallisation experiments carried out using magnesium nitrate. The effect of residence time on crystal growth was studied. At residence time of 10, 30 and 60 minutes, mean particle sizes were 17, 34 and 53 µm showing that with higher residence times, larger crystal sizes can be achieved. SEM analysis of the crystal showed that the resultant crystals had the typical morphology of struvite crystals.

Keywords: struvite, magnesium nitrate, crystallisation, urine treatment

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Authors: Abubakar Halidu, Paul E. Bilsborrow, Anh N. Phan

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Torrefaction is a term that refers to the moderate pyrolysis of biomass at temperatures between 200 and 300oC in an oxygen-free environment to boost its heating value, grindability, and storability. This process can also be used as a pre-treatment for other thermochemical processes. The torrefaction of spelt husks was carried out at temperatures of 200, 250, and 300oC in an inert nitrogen environment with a heating rate of 20oC.min-1 and a residence time of 15–60 min, respectively. We examined the influence of torrefaction temperatures and residence time. The results indicated that increasing the torrefaction temperature increased the higher heating values (HHV) and improved grindability. Torrefied spelt husks at 300oC for 15 minutes exhibited the highest increase in HHV at 30.88 MJ kg-1, compared to non-torrefied spelt husks at 17.56 MJ kg-1.

Keywords: grindability, higher heating value, residence time, temperature, torrefaction

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Authors: Amanda Maria Rodrigues Barroso, Ary Paixao Borges Santana Junior, Caio Araujo Damasceno

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In Piauí, the Brazilian state, solar energy has become one of the renewable sources targeted by internal and external investments, with the intention of leveraging the development of society. However, for a residential or business consumer to be able to deploy this source, there is usually a need for a high initial investment due to its high cost. The countless high taxes on equipment and services are one of the factors that contribute to this cost and ultimately fall on the consumer. Through analysis, a way of reducing taxes is sought in order to encourage consumer adhesion to the use of photovoltaic solar energy. Thus, the objective is to implement the Piauí Solar Program in the state of Piauí in order to stimulate the deployment of photovoltaic solar energy, through benefits granted to users, providing state development by boosting the diversification of the state's energy matrix. The research method adopted was based on the analysis of data provided by the Teresina City Hall, by the Brazilian Institute of Geography and Statistics and by a private company in the capital of Piauí. The account was taken of the total amount paid in Property and Urban Territorial Property Tax (IPTU), in electricity and in the service of installing photovoltaic panels in a residence with 6 people. Through Piauí Solar, a discount of 80% would be applied to the taxes present in the budgets regarding the implementation of these photovoltaic plates in homes and businesses, as well as in the IPTU. In addition, another factor also taken into account is the energy savings generated after the implementation of these boards. In the studied residence, the annual payment of IPTU went from R $ 99.83 reais to R $ 19.96, the reduction of taxes present in the budget for the implantation of solar panels, caused the value to increase from R $ 42,744.22 to R $ 37,241.98. The annual savings in electricity bills were estimated at around R $ 6,000. Therefore, there is a reduction of approximately 24% in the total invested. The trend of the Piauí Solar program, then, is to bring benefits to the state, providing an improvement in the living conditions of the population, through the savings generated by this program. In addition, an increase in the diversification of the Piauí energy matrix can be seen with the advancement of the use of this renewable energy.

Keywords: development, economy, energy, taxes

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Authors: Dara Satyadileep, Abdallah S. Berrouk

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Selective absorption of Hydrogen Sulphide (H2S) using methyldiethanol amine (MDEA) has become a point of interest as means of minimizing capital and operating costs of gas sweetening plants. This paper discusses the prominence of optimum design of column internals to best achieve H2S selectivity using MDEA. To this end, a kinetics-based process simulation model has been developed for a commercial gas sweetening unit. Trends of sweet gas H2S & CO2 contents as function of fraction active area (and hence residence time) have been explained through analysis of interdependent heat and mass transfer phenomena. Guidelines for column internals design in order to achieve desired degree of H2S selectivity are provided. Also the effectiveness of various operating conditions in achieving H2S selectivity for an industrial absorber with fixed internals is investigated.

Keywords: gas sweetening, H2S selectivity, methyldiethanol amine, process simulation, residence time

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Authors: Farideh Gheitasi, Zahra Mirzaei Pour

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Considering mutual interactions of industry and residence in an environmental point of view is essential in effective urban management and all the policies must be made based on the results of these interactions. So, District No 21 of Tehran Municipality (Iran) which is almost industrial combined with some residential area was selected to study the consequences of industrial and residential area neighborhood. In this paper the results of two observations conducted in two timescales in 2010 and 2015, according to completed questionnaires by residents of an industrial region in the study area, were analyzed. The questionnaires contain 19 different environmental parameters considering positive and negative effects of industry on human life. The results of this study show that 96% of the target group in 2010 believed if the companies regard the law, mutual coexistence of industry and residency is possible. While this number decreased to 21% in 2015, which indicates that the problem got worse and people became more unsatisfied with the situation.

Keywords: environment, industry, residence, pollution

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Authors: Li-Jun Ren, Wei Pan, Li-Li Xu, Shu-Qing An

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This study evaluated whether different matrix composition volume ratio can improve water quality in the experiment. The mechanism and adsorption capability of wetland matrixes (oyster shell, coarse slag, and volcanic rock) and their different volume ratio in group configuration during pollutants removal processes were tested. When conditions unchanged, the residence time affects the reaction effect. The average removal efficiencies of four kinds of matrix volume ratio on the TN were 62.76%, 61.54%, 64.13%, and 55.89%, respectively.

Keywords: hydraulic residence time, matrix composition, removal efficiency, volume ratio

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Authors: Balram Panjwani, Bernd Wittgens, Jan Erik Olsen, Stein Tore Johansen

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The Norwegian ferroalloy industry is a world leader in sustainable production of ferrosilicon, silicon and manganese alloys with the lowest global specific energy consumption. One of the byproducts during the metal reduction process is energy rich off-gas and usually this energy is not harnessed. A novel concept for sustainable energy recovery from ferroalloy off-gas is discussed. The concept is founded on the idea of introducing a combustion chamber in the off-gas section in which energy rich off-gas mainly consisting of CO will be combusted. This will provide an additional degree of freedom for optimizing energy recovery. A well-controlled and high off-gas temperature will assure a significant increase in energy recovery and reduction of emissions to the atmosphere. Design and operation of the combustion chamber depend on many parameters, including the total power capacity of the combustion chamber, sufficient residence time for combusting the complex Poly Aromatic Hydrocarbon (PAH), NOx, as well as converting other potential pollutants. The design criteria for the combustion chamber have been identified and discussed and sizing of the combustion chamber has been carried out considering these design criteria. Computational Fluid Dynamics (CFD) has been utilized extensively for sizing the combustion chamber. The results from our CFD simulations of the flow in the combustion chamber and exploring different off-gas fuel composition are presented. In brief, the paper covers all aspect which impacts the sizing of the combustion chamber, including insulation thickness, choice of insulating material, heat transfer through extended surfaces, multi-staging and secondary air injection.

Keywords: CFD, combustion chamber, arc furnace, energy recovery

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Authors: Tomoya Oshiro, Hiroko Ono

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Japan's aging population is increasing due to the decrease in birthrate. It causes various problems like the decrease in the gross domestic product of the country. The reason is why the local government of Japan has been on the way to a sustainable city recently. Then it is essential to get control of an urban structure to make the compact city successful. There are many kinds of paper about the compact city; however, the paper about a compact city of the island-type city is less. The purpose of this study is to clarify difference of urban structure between an island-type and a general city type. The method which has conducted in this research has two steps. First of all, by using evaluation indexes in the handbook, we evaluated the urban structures among each same -population-class cities from 50,000 to 100,000 people. Next, to clear the difference about the urban structure and feature between island-type and general-type cities compare the radar chart which is composed with each evaluation indexes of urban structure. Moreover, in order to clarify the relationship between evaluation indexes and the place of residence by using GIS software to show up population density on the map. As a result of this research, the management of local government and the local economy in evaluation indexes are indicated to be negative point in comparison of island-type cities with general cities. However, evaluation indexes of safety/security and low-carbon/energy are proved to be positive point. The research to find the difference features of the island-type of urban structure proves that the management of local government or the local economy is negative point in these island-type cities. In addition, the public transportation coverage in Miyako Island, Sado Island, and Amakusa Island show low value compare with other islands and average value. Relationship between evaluation indexes of an urban structure and the place of residence prove that the place of residence is related to public transportation coverage. If the place of residence is spread out, the public transportation coverage will be decreased. The results of this research reveal that the finances in island-type cities are negative point compare to general cities. This problem is caused by declining population. In addition, the place of residence is related to the public transportation coverage. Even though, it needs a much money to increase the public transportation coverage. It is possibly to cause other problems furthermore the aspect of finance is influenced by that as well. The conclusion in this research suggests that it is important for creating the compact city in island-type cities that we first need to address solving the problems about the management of local government and the local economy.

Keywords: sustainable city, comparative analysis, geographic information system, urban structure

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Authors: Edgar Gasafi, Robert Pardemann, Linus Perander

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For the production of lithium carbonate or hydroxide out of lithium bearing ores, a thermal activation (calcination/decrepitation) is required for the phase transition in the mineral to enable an acid respectively soda leaching in the downstream hydrometallurgical section. In this paper, traditional processing in Lithium industry is reviewed, and opportunities to reduce energy consumption and improve product quality and recovery rate will be discussed. The conventional process approach is still based on rotary kiln calcination, a technology in use since the early days of lithium ore processing, albeit not significantly further developed since. A new technology, at least for the Lithium industry, is fluidized bed calcination. Decrepitation of lithium ore was investigated at Outotec’s Frankfurt Research Centre. Focusing on fluidized bed technology, a study of major process parameters (temperature and residence time) was performed at laboratory and larger bench scale aiming for optimal product quality for subsequent processing. The technical feasibility was confirmed for optimal process conditions on pilot scale (400 kg/h feed input) providing the basis for industrial process design. Based on experimental results, a comprehensive Aspen Plus flow sheet simulation was developed to quantify mass and energy flow for the rotary kiln and fluidized bed system. Results show a significant reduction in energy consumption and improved process performance in terms of temperature profile, product quality and plant footprint. The major conclusion is that a substantial reduction of energy consumption can be achieved in processing Lithium bearing ores by using fluidized bed based systems. At the same time and different from rotary kiln process, an accurate temperature and residence time control is ensured in fluidized-bed systems leading to a homogenous temperature profile in the reactor which prevents overheating and sintering of the solids and results in uniform product quality.

Keywords: calcination, decrepitation, fluidized bed, lithium, spodumene

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Authors: Faisal Saleem, Kui Zhang, Adam Harvey

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The role of N₂ carrier gas towards the conversion of tar analogue was studied in a non-thermal plasma dielectric barrier discharge (DBD) reactor. The important parameters such as power (5-40W), residence time (1.41-4.23 s), concentration (20-82 g/Nm³), and temperature (Ambient-400°C) were explored. The present study demonstrated that plasma power and residence time played a key role in the decomposition of toluene, and almost complete removal of toluene was observed at 40w and 4.23 s. H₂ is obtained as a major gaseous product with a maximum selectivity of 40% along with some lighter hydrocarbons (5.5%). The removal efficiency of toluene slightly decreases with increasing the concentration of toluene from 20 g/Nm³ to 82 g/Nm³. The solid residue formation takes place inside the plasma reactor. The selectivity of LHC (lower hydrocarbons) increased up to 15% by increasing the temperature to 400°C. Introducing H₂ to the gas at elevated temperature opens up new reaction routes to raise the selectivity to lower hydrocarbons. The selectivity to methane reaches to 42% using 35% H₂ at 400°C and total selectivity of LHC increases to 57%.

Keywords: biomass gasification tar, non-thermal plasma, dielectric barrier discharge, residence time

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Authors: K. M. Etmimi, A. A. Sghayer, A. M. Gsiea, A. M. Abutruma

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Relatively few chemical species can be incorporated into diamond during CVD growth, and until recently the uptake of oxygen was thought to be low perhaps as a consequence of a short surface residence time. Within the literature, there is speculation regarding spectroscopic evidence for O in diamond, but no direct evidence. For example, the N3 and OK1 EPR centres have been tentatively assigned models made up from complexes of substitutional N and substitutional oxygen. In this study, we report density-functional calculations regarding the stability, electronic structures, geometry and hyperfine interaction of substitutional oxygen in diamond and show that the C2v, S=1 configuration very slightly lower in energy than the other configurations (C3v, Td, and C2v with S=0). The electronic structure of O in diamond generally gives rise to two defect-related energy states in the band gap one a non-degenerate a1 state lying near the middle of the energy gap and the other a threefold-degenerate t2 state located close to the conduction band edges. The anti-bonding a1 and t2 states will be occupied by one to three electrons for O+, O and O− respectively.

Keywords: DFT, oxygen, diamond, hyperfine

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Authors: T. Costa, D. Narvaez, K. Melo, M. Villalva

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Installation of micro-generators based on renewable energy in power distribution system has increased in recent years, with the main renewable sources being solar and wind. Due to the intermittent nature of renewable energy sources, such micro-generators produce time-varying energy which does not correspond at certain times of the day to the peak energy consumption of end users. For this reason, the use of energy storage units next to the grid contributes to the proper leveling of the buses’ voltage level according to Brazilian energy quality standards. In this work, the effect of the addition of a photovoltaic solar generator and a store of energy in the busbar voltages of an electric system is analyzed. The consumption profile is defined as the average hourly use of appliances in a common residence, and the generation profile is defined as a function of the solar irradiation available in a locality. The power summation method is validated with analytical calculation and is used to calculate the modules and angles of the voltages in the buses of an electrical system based on the IEEE standard, at each hour of the day and with defined load and generation profiles. The results show that bus 5 presents the worst voltage level at the power consumption peaks and stabilizes at the appropriate range with the inclusion of the energy storage during the night time period. Solar generator maintains improvement of the voltage level during the period when it receives solar irradiation, having peaks of production during the 12 pm (without exceeding the appropriate maximum levels of tension).

Keywords: energy storage, power distribution system, solar generator, voltage level

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Authors: Jenan Shakoor

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Obesity prevalence is increasing worldwide. University life is a challenging period especially for students who have to leave their familiar surroundings and settle in a new environment. The current study aimed to assess the diet and exercise habits and their association with body mass index (BMI) among nursing college students living at Kirkuk University residence. This was a descriptive study. A non-probability (purposive) sample of 101 students living in Kirkuk University residence was recruited during the period from the 15^th November 2015 to the 5^th May 2016. A questionnaire was constructed for the purpose of the study which consisted of four parts: the demographic characteristics of the study sample, eating habits, eating at college and healthy habits. The data were collected by interviewing the study sample and the weight and height were measured by a trained researcher at the college. Descriptive statistical analysis was undertaken. Data were prepared, organized and entered into the computer file; the Statistical Package for Social Science (SPSS 20) was used for data analysis. A p value≤ 0.05 was accepted as statistical significant. A total of 63 (62.4%) of the sample were aged20-21with a mean age of 22.1 (SD±0.653). A third of the sample 38 (37.6%) were from level four at college, 67 (66.3%) were female and 46 45.5% of participants were from a middle socio-economic status. 14 (13.9%) of the study sample were overweight (BMI =25-29.9kg/m²) and 6 (5.9%) were obese (BMI≥30kg/m²) compared to 73 (72.3%) were of normal weight (BMI =18.5-24.9kg/m²). With regard to eating habits and exercise, 42 (41.6%) of the students rarely ate breakfast, 79 (78.2%) eat lunch at university residence, 77 (78.2%) of the students reported rarely doing exercise and 62 (61.4%) of them were sleeping for less than eight hours. No significant association was found between the variables age, sex, level of college and socio-economic status and BMI, while there was a significant association between eating lunch at university and BMI (p =0.03). No significant association was found between eating habits, healthy habits and BMI. The prevalence of overweight and obesity among the study sample was 19.8% with female students being more obese than males. Further studies are needed to identify BMI among residence students in other colleges and increasing the awareness of undergraduate students to healthy food habits.

Keywords: body mass index, diet, obesity, university residence

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Authors: Harveen Kaur Tatla, Parisa Niknejad, Rajender Gupta, Bipro Ranjan Dhar, Mohd. Adana Khan

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Sewage sludge management presents a pressing challenge in the realm of wastewater treatment, calling for sustainable and efficient solutions. This study explores the integration of Hydrothermal Liquefaction (HTL) and Anaerobic Digestion (AD) as a promising approach to address the complexities associated with sewage sludge treatment. The integration of these two processes offers a complementary and synergistic framework, allowing for the mitigation of inherent limitations, thereby enhancing overall efficiency, product quality, and the comprehensive utilization of sewage sludge. In this research, we investigate the optimal sequencing of HTL and AD within the treatment framework, aiming to discern which sequence, whether HTL followed by AD or AD followed by HTL, yields superior results. We explore a range of HTL working temperatures, including 250°C, 300°C, and 350°C, coupled with residence times of 30 and 60 minutes. To evaluate the effectiveness of each sequence, a battery of tests is conducted on the resultant products, encompassing Total Ammonia Nitrogen (TAN), Chemical Oxygen Demand (COD), and Volatile Fatty Acids (VFA). Additionally, elemental analysis is employed to determine which sequence maximizes energy recovery. Our findings illuminate the intricate dynamics of HTL and AD integration for sewage sludge management, shedding light on the temperature-residence time interplay and its impact on treatment efficiency. This study not only contributes to the optimization of sewage sludge treatment but also underscores the potential of integrated processes in sustainable waste management strategies. The insights gleaned from this research hold promise for advancing the field of wastewater treatment and resource recovery, addressing critical environmental and energy challenges.

Keywords: Anaerobic Digestion (AD), aqueous phase, energy recovery, Hydrothermal Liquefaction (HTL), sewage sludge management, sustainability.

Procedia PDF Downloads 80

Authors: Angelica Gonzalez O, Leonardo Rivera Cadavid, Diego Fernando Manotas

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Energy poverty considers a population that does not have access to modern energy service. In particular, an area of a country that is not connected to the national electricity grid is known as a Non-Interconnected Zone (NIZ). Access to electricity has a significant impact on the welfare and development opportunities of the population. Different studies have shown that most health problems have an empirical cause and effect relationship with multidimensional energy poverty. Likewise, research has been carried out to review the consequences of not having access to electricity, and its results have concluded a statistically significant relationship between energy poverty and sources of drinking water, access to clean water, risks of mosquito bites, obesity, sterilization, marital status, occupation, and residence. Therefore, extensive research has been conducted in the construction of an energy poverty measure based on an index. Some of these studies introduce a Multidimensional Energy Poverty Index (MEPI), Compose Energy Poverty Index (CEPI), Low Income High Costs indicator (LIHC), among others. For this purpose, this study analyzes the energy poverty index using a multicriteria analysis determining the set of feasible alternatives - for which Colombia's ZNI will be used as a case study - to be considered in the problem and the set of relevant criteria in the characterization of the ZNI, from which the prioritization is obtained to determine the level of adjustment of each alternative with respect to the performance in each criterion. Additionally, this study considers the installation of Micro-Grids (MG). This is considered a straightforward solution to this problem because an MG is a local electrical grid, able to operate in grid-connected and island mode. Drawing on those insights, this study compares an energy poverty index considering an MG installation and calculates the impacts of different criterias in an energy poverty index in NIZ.

Keywords: multicirteria, energy poverty, rural, microgrids, non-interconnect zones

Procedia PDF Downloads 117

Authors: Gyo Woo Lee, Man Young Kim

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A mathematical heat transfer model for the prediction of transient heating of the slab in a direct-fired walking beam type reheating furnace has been developed by considering the nongray thermal radiation with given furnace environments. The furnace is modeled as radiating nongray medium with carbon dioxide and water with five-zoned gas temperature and the furnace wall is considered as a constant temperature lower than furnace gas one. The slabs are moving with constant velocity depending on the residence time through the non-firing, charging, preheating, heating, and final soaking zones. Radiative heat flux obtained by considering the radiative heat exchange inside the furnace as well as convective one from the surrounding hot gases are introduced as boundary condition of the transient heat conduction within the slab. After validating thermal radiation model adopted in this work, thermal fields in both model and real reheating furnace are investigated in terms of radiative heat flux in the furnace and temperature inside the slab. The results show that the slab in the furnace can be more heated with higher slab emissivity and residence time.

Keywords: reheating furnace, steel slab, radiative heat transfer, WSGGM, emissivity, residence time

Procedia PDF Downloads 287

Authors: A. Alzeyadi, E. Loffill, R. Alkhaddar

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Continuous upflow filters can combine the nutrient (nitrogen and phosphate) and suspended solid removal in one unit process. The contaminant removal could be achieved chemically or biologically; in both processes the filter removal efficiency depends on the interaction between the packed filter media and the influent. In this paper a residence time distribution (RTD) study was carried out to understand and compare the transfer behaviour of contaminants through a selected filter media packed in a laboratory-scale continuous up flow filter; the selected filter media are limestone and white dolomite. The experimental work was conducted by injecting a tracer (red drain dye tracer –RDD) into the filtration system and then measuring the tracer concentration at the outflow as a function of time; the tracer injection was applied at hydraulic loading rates (HLRs) (3.8 to 15.2 m h-1). The results were analysed according to the cumulative distribution function F(t) to estimate the residence time of the tracer molecules inside the filter media. The mean residence time (MRT) and variance σ2 are two moments of RTD that were calculated to compare the RTD characteristics of limestone with white dolomite. The results showed that the exit-age distribution of the tracer looks better at HLRs (3.8 to 7.6 m h-1) and (3.8 m h-1) for limestone and white dolomite respectively. At these HLRs the cumulative distribution function F(t) revealed that the residence time of the tracer inside the limestone was longer than in the white dolomite; whereas all the tracer took 8 minutes to leave the white dolomite at 3.8 m h-1. On the other hand, the same amount of the tracer took 10 minutes to leave the limestone at the same HLR. In conclusion, the determination of the optimal level of hydraulic loading rate, which achieved the better influent distribution over the filtration system, helps to identify the applicability of the material as filter media. Further work will be applied to examine the efficiency of the limestone and white dolomite for phosphate removal by pumping a phosphate solution into the filter at HLRs (3.8 to 7.6 m h-1).

Keywords: filter media, hydraulic loading rate, residence time distribution, tracer

Procedia PDF Downloads 277

Authors: Chayanoot Sangwichien, Taweesak Reungpeerakul, Kyaw Thu

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Oil palm mills in Southern Thailand produced a large amount of biomass solid wastes. Lignocellulose biomass is the main source for production of biofuel which can be combined or used as an alternative to fossil fuels. Biomass composed of three main constituents of cellulose, hemicellulose, and lignin. Thermochemical conversion process applied to produce biofuel from biomass. Pyrolysis of biomass is the best way to thermochemical conversion of biomass into pyrolytic products (bio-oil, gas, and char). Operating parameters play an important role to optimize the product yields from fast pyrolysis of biomass. This present work concerns with the modeling of reaction kinetics parameters for fast pyrolysis of empty fruit bunch in the fluidized bed reactor. A global kinetic model used to predict the product yields from fast pyrolysis of empty fruit bunch. The reaction temperature and vapor residence time parameters are mainly affected by product yields of EFB pyrolysis. The reaction temperature and vapor residence time parameters effects on empty fruit bunch pyrolysis are considered at the reaction temperature in the range of 450-500˚C and at a vapor residence time of 2 s, respectively. The optimum simulated bio-oil yield of 53 wt.% obtained at the reaction temperature and vapor residence time of 450˚C and 2 s, 500˚C and 1 s, respectively. The simulated data are in good agreement with the reported experimental data. These simulated data can be applied to the performance of experiment work for the fast pyrolysis of biomass.

Keywords: kinetics, empty fruit bunch, fast pyrolysis, modeling

Procedia PDF Downloads 213

Authors: Letizia Marchetti, Federica Annunzi, Federico Fiorini, Cristiano Nicolella

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Automotive shredder residue (ASR) is a mixture of waste that makes up 20-25% of end-of-life vehicles. For many years, ASR was commonly disposed of in landfills or incinerated, causing serious environmental problems. Nowadays, thermochemical treatments are a promising alternative, although the heterogeneity of ASR still poses some challenges. One of the emerging thermochemical treatments for ASR is pyrolysis, which promotes the decomposition of long polymeric chains by providing heat in the absence of an oxidizing agent. In this way, pyrolysis promotes the conversion of ASR into solid, liquid, and gaseous phases. This work aims to improve the performance of a two-step pyrolysis process. After the characterization of the analysed ASR, the focus is on determining the effects of residence time on product yields and gas composition. A batch experimental setup that reproduces the entire process was used. The setup consists of three sections: the pyrolysis section (made of two reactors), the separation section, and the analysis section. Two different residence times were investigated to find suitable conditions for the first sample of ASR. These first tests showed that the products obtained were more sensitive to residence time in the second reactor. Indeed, slightly increasing residence time in the second reactor managed to raise the yield of gas and carbon residue and decrease the yield of liquid fraction. Then, to test the versatility of the setup, the same conditions were applied to a different sample of ASR coming from a different chemical plant. The comparison between the two ASR samples shows that similar product yields and compositions are obtained using the same setup.

Keywords: automotive shredder residue, experimental tests, heterogeneity, product yields, two-step pyrolysis

Procedia PDF Downloads 126

Authors: Robson C. Santos, David D. Oliveira, Matheus M. Reis, Gerson G. Cunha, Marcos A. C. Moreira

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The project demonstrates the construction of a solar power generation, integrated inverter equipment to a "Grid-Tie" by converting direct current generated by solar panels, into alternating current, the same parameters of frequency and voltage concessionaire distribution network. The energy generated is quantified by smart metering module that transmits the information in specified periods of time to a microcontroller via GSM modem. The modem provides the measured data on the internet, using networks and cellular antennas. The monitoring, fault detection and maintenance are performed by a supervisory station. Employed board types, best inverter selection and studies about control equipment and devices have been described. The article covers and explores the global trend of implementing smart distribution electrical energy networks and the incentive to use solar renewable energy. There is the possibility of the excess energy produced by the system be purchased by the local power utility. This project was implemented in residences in the rural community of the municipality of Cabo Frio/RJ. Data could be seen through daily measurements during the month of November 2013.

Keywords: rural residence, supervisory, smart grid, solar energy

Procedia PDF Downloads 593

Authors: Denise Bianco

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Several studies on innovation and creativity in organisations emphasise the need to expand horizons and take on alternative and unexpected views to produce something new. This paper theorises the potential impact artists can have as creative catalysts, working embedded in non-artistic organisations. It begins from an understanding that in today's ever-changing scenario, organisations are increasingly seeking to open up new creative thinking through deviant behaviours to produce innovation and that art residencies need to be critically revised in this specific context in light of their disruptive potential. On the one hand, this paper builds upon recent contributions made on workplace creativity and related concepts of deviance and disruption. Research suggests that creativity is likely to be lower in work contexts where utter conformity is a cardinal value and higher in work contexts that show some tolerance for uncertainty and deviance. On the other hand, this paper draws attention to Artist-in-Residence as a vehicle for epistemic friction between divergent and convergent thinking, which allows the creation of unparalleled ways of knowing in the dailiness of situated and contextualised social processes. In order to do so, this contribution brings together insights from the most relevant theories on organisational creativity and unconventional agile methods such as Art Thinking and direct insights from ethnographic fieldwork in the context of embedded art residencies within work organisations to propose a redefinition of Artist-in-Residence and their potential impact on organisational creativity. The result is a re-definition of embedded Artist-in-Residence in organisational settings from a more comprehensive, multi-disciplinary, and relational perspective that builds on three focal points. First the notion that organisational creativity is a dynamic and synergistic process throughout which an idea is framed by recurrent activities subjected to multiple influences. Second, the definition of embedded Artist-in-Residence as an assemblage of dynamic, productive relations and unexpected possibilities for new networks of relationality that encourage the recombination of knowledge. Third, and most importantly, the acknowledgment that embedded residencies are, at the very essence, bi-cultural knowledge contexts where creativity flourishes as the result of open-to-change processes that are highly relational, constantly negotiated, and contextualised in time and space.

Keywords: artist-in-residence, convergent and divergent thinking, creativity, creative friction, deviance and creativity

Procedia PDF Downloads 97