Search results for: urban heat islands
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 6688

Search results for: urban heat islands

1048 Phase Optimized Ternary Alloy Material for Gas Turbines

Authors: Mayandi Ramanathan

Abstract:

Gas turbine blades see the most aggressive thermal stress conditions within the engine, due to Turbine Entry Temperatures in the range of 1500 to 1600°C, but in synchronization with other functional components, they must readily deliver efficient performance, whilst incurring minimal overhaul and repair costs during its service life up to 5 million flying miles. The blades rotate at very high rotation rates and remove significant amount of thermal power from the gas stream. At high temperatures the major component failure mechanism is creep. During its service over time under high temperatures and loads, the blade will deform, lengthen and rupture. High strength and stiffness in the longitudinal direction up to elevated service temperatures are certainly the most needed properties of turbine blades. The proposed advanced Ti alloy material needs a process that provides strategic orientation of metallic ordering, uniformity in composition and high metallic strength. 25% Ta/(Al+Ta) ratio ensures TaAl3 phase formation, where as 51% Al/(Al+Ti) ratio ensures formation of α-Ti3Al and γ-TiAl mixed phases fand the three phase combination ensures minimal Al excess (~1.4% Al excess), unlike Ti-47Al-2Cr-2Nb which has significant excess Al (~5% Al excess) that could affect the service life of turbine blades. This presentation will involve the summary of additive manufacturing and heat treatment process conditions to fabricate turbine blade with Ti-43Al matrix alloyed with optimized amount of refractory Ta metal. Summary of thermo-mechanical test results such as high temperature tensile strength, creep strain rate, thermal expansion coefficient and fracture toughness will be presented. Improvement in service temperature of the turbine blades and corrosion resistance dependence on coercivity of the alloy material will be reported. Phase compositions will be quantified, and a summary of its correlation with creep strain rate will be presented.

Keywords: gas turbine, aerospace, specific strength, creep, high temperature materials, alloys, phase optimization

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1047 Assessment Of The Thermal And Mechanical Properties Of Bio-based Composite Materials For Thermal Insulation

Authors: Nega Tesfie Asfaw, Rafik Absi, Labouda B.a, And Ikram El Abbassi

Abstract:

Composite materials have come to the fore a few decades ago because of their superior insulation performances. Recycling natural fiber composites and natural fiber reinforcement of waste materials are other steps for conserving resources and the environment. This paper reviewed the Thermal properties (Thermal conductivity, Effusivity, and Diffusivity) and Mechanical properties (Compressive strength, Flexural strength, and Tensile strength) of bio-composite materials for thermal insulation in the construction industry. For several years, the development of the building materials industry has placed a special emphasis on bio-source materials. According to recent studies, most natural fibers have good thermal insulating qualities and good mechanical properties. To determine the thermal and mechanical performance of bio-composite materials in construction most research used experimental methods. the results of the study show that these natural fibers have allowed us to optimize energy consumption in a building and state that density, porosity, percentage of fiber, the direction of heat flow orientation of the fiber, and the shape of the specimen are the main elements that limit the thermal performance and also showed that density, porosity, Type of Fiber, Fiber length, orientation and weight percentage loading, Fiber-matrix adhesion, Choice of the polymer matrix, Presence of void are the main elements that limit the mechanical performance of the insulation material. Based on the results of this reviewed paper Moss fibers (0.034W/ (m. K)), Wood Fiber (0.043 W/ (m. K)), Wheat straw (0.046 W/ (m. K), and corn husk fibers (0.046 W/ (m. K) are a most promising solution for energy efficiency for construction industry with interesting insulation properties and with good acceptable mechanical properties. Finally, depending on the best fibers used for insulation applications in the construction sector, the thermal performance rate of various fibers reviewed in this article are analyzed. Due to Typha's high porosity, the results indicated that Typha australis fiber had a better thermal performance rate of 89.03% with clay.

Keywords: bio-based materials, thermal conductivity, compressive strength, thermal performance

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1046 Assessing the Impacts of Urbanization on Urban Precincts: A Case of Golconda Precinct, Hyderabad

Authors: Sai AKhila Budaraju

Abstract:

Heritage sites are an integral part of cities and carry a sense of identity to the cities/ towns, but the process of urbanization is a carrying potential threat for the loss of these heritage sites/monuments. Both Central and State Governments listed the historic Golconda fort as National Important Monument and the Heritage precinct with eight heritage-listed buildings and two historical sites respectively, for conservation and preservation, due to the presence of IT Corridor 6kms away accommodating more people in the precinct is under constant pressure. The heritage precinct possesses high property values, being a prime location connecting the IT corridor and CBD (central business district )areas. The primary objective of the study was to assess and identify the factors that are affecting the heritage precinct through Mapping and documentation, Identifying and assessing the factors through empirical analysis, Ordinal regression analysis and Hedonic Pricing Model. Ordinal regression analysis was used to identify the factors that contribute to the changes in the precinct due to urbanization. Hedonic Pricing Model was used to understand and establish a relation whether the presence of historical monuments is also a contributing factor to the property value and to what extent this influence can contribute. The above methods and field visit indicates the Physical, socio-economic factors and the neighborhood characteristics of the precinct contributing to the property values. The outturns and the potential elements derived from the analysis of the Development Control Rules were derived as recommendations to Integrate both Old and newly built environments.

Keywords: heritage planning, heritage conservation, hedonic pricing model, ordinal regression analysis

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1045 Assessing the Impact of Low Carbon Technology Integration on Electricity Distribution Networks: Advancing towards Local Area Energy Planning

Authors: Javier Sandoval Bustamante, Pardis Sheikhzadeh, Vijayanarasimha Hindupur Pakka

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In the pursuit of achieving net-zero carbon emissions, the integration of low carbon technologies into electricity distribution networks is paramount. This paper delves into the critical assessment of how the integration of low carbon technologies, such as heat pumps, electric vehicle chargers, and photovoltaic systems, impacts the infrastructure and operation of electricity distribution networks. The study employs rigorous methodologies, including power flow analysis and headroom analysis, to evaluate the feasibility and implications of integrating these technologies into existing distribution systems. Furthermore, the research utilizes Local Area Energy Planning (LAEP) methodologies to guide local authorities and distribution network operators in formulating effective plans to meet regional and national decarbonization objectives. Geospatial analysis techniques, coupled with building physics and electric energy systems modeling, are employed to develop geographic datasets aimed at informing the deployment of low carbon technologies at the local level. Drawing upon insights from the Local Energy Net Zero Accelerator (LENZA) project, a comprehensive case study illustrates the practical application of these methodologies in assessing the rollout potential of LCTs. The findings not only shed light on the technical feasibility of integrating low carbon technologies but also provide valuable insights into the broader transition towards a sustainable and electrified energy future. This paper contributes to the advancement of knowledge in power electrical engineering by providing empirical evidence and methodologies to support the integration of low carbon technologies into electricity distribution networks. The insights gained are instrumental for policymakers, utility companies, and stakeholders involved in navigating the complex challenges of energy transition and achieving long-term sustainability goals.

Keywords: energy planning, energy systems, digital twins, power flow analysis, headroom analysis

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1044 Magnetic Bio-Nano-Fluids for Hyperthermia

Authors: Z. Kolacinski, L. Szymanski. G. Raniszewski, D. Koza, L. Pietrzak

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Magnetic Bio-Nano-Fluid (BNF) can be composed of a buffer fluid such as plasma and magnetic nanoparticles such as iron, nickel, cobalt and their oxides. However iron is one of the best elements for magnetization by electromagnetic radiation. It can be used as a tool for medical diagnosis and treatment. Radio frequency (RF) radiation is able to heat iron nanoparticles due to magnetic hysteresis. Electromagnetic heating of iron nanoparticles and ferro-fluids BNF can be successfully used for non-invasive thermal ablation of cancer cells. Moreover iron atoms can be carried by carbon nanotubes (CNTs) if iron is used as catalyst for CNTs synthesis. Then CNTs became the iron containers and they screen the iron content against oxidation. We will present a method of CNTs addressing to the required cells. For thermal ablation of cancer cells we use radio frequencies for which the interaction with human body should be limited to minimum. Generally, the application of RF energy fields for medical treatment is justified by deep tissue penetration. The highly iron doped CNTs as the carriers creating magnetic fluid will be presented. An excessive catalyst injection method using electrical furnace and microwave plasma reactor will be presented. This way it is possible to grow the Fe filled CNTs on a moving surface in continuous synthesis process. This also allows producing uniform carpet of the Fe filled CNTs carriers. For the experimental work targeted to cell ablation we used RF generator to measure the increase in temperature for some samples like: solution of Fe2O3 in BNF which can be plasma-like buffer, solutions of pure iron of different concentrations in plasma-like buffer and in buffer used for a cell culture, solutions of carbon nanotubes (MWCNTs) of different concentrations in plasma-like buffer and in buffer used for a cell culture. Then the targeted therapies which can be effective if the carriers are able to distinguish the difference between cancerous and healthy cell’s physiology are considered. We have developed an approach based on ligand-receptor or antibody-antigen interactions for the case of colon cancer.

Keywords: cancer treatment, carbon nano tubes, drag delivery, hyperthermia, iron

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1043 Spatial Distribution and Time Series Analysis of COVID-19 Pandemic in Italy: A Geospatial Perspective

Authors: Muhammad Farhan Ul Moazzam, Tamkeen Urooj Paracha, Ghani Rahman, Byung Gul Lee, Nasir Farid, Adnan Arshad

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The novel coronavirus pandemic disease (COVID-19) affected the whole globe, though there is a lack of clinical studies and its epidemiological features. But as per the observation, it has been seen that most of the COVID-19 infected patients show mild to moderate symptoms, and they get better without any medical assistance due to a better immune system to generate antibodies against the novel coronavirus. In this study, the active cases, serious cases, recovered cases, deaths and total confirmed cases had been analyzed using the geospatial inverse distance weightage technique (IDW) within the time span of 2nd March to 3rd June 2020. As of 3rd June, the total number of COVID-19 cases in Italy were 231,238, total deaths 33,310, serious cases 350, recovered cases 158,951, and active cases were 39,177, which has been reported by the Ministry of Health, Italy. March 2nd-June 3rd, 2020 a sum of 231,238 cases has been reported in Italy out of which 38.68% cases reported in the Lombardia region with a death rate of 18%, which is high from its national mortality rate followed by Emilia-Romagna (14.89% deaths), Piemonte (12.68% deaths), and Vento (10% deaths). As per the total cases in the region, the highest number of recoveries has been observed in Umbria (92.52%), followed by Basilicata (87%), Valle d'Aosta (86.85%), and Trento (84.54%). The COVID-19 evolution in Italy has been particularly found in the major urban area, i.e., Rome, Milan, Naples, Bologna, and Florence. Geospatial technology played a vital role in this pandemic by tracking infected patient, active cases, and recovered cases. Geospatial techniques are very important in terms of monitoring and planning to control the pandemic spread in the country.

Keywords: COVID-19, public health, geospatial analysis, IDW, Italy

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1042 Understanding the Issue of Reproductive Matters among Urban Women: A Study of Four Cities in India from National Family Health Survey-4

Authors: Priyanka Dixit

Abstract:

Reproductive health problem is an important public health issue in most of the developing countries like India. It is a common problem in India for women in the reproductive age group to suffer from reproductive illnesses and not seek care. Existing literatures tell us very little about the several dimensions of reproductive morbidity. In addition the general perception says, metros have better medical infrastructure, so its residents should lead a healthier life. However some of the studies reveal a very different picture. Therefore, the present study is conducted with the specific objectives to find out the prevalence of reproductive health problem and treatment seeking behavior of currently married women in four metro cities in India namely; Mumbai, Delhi, Chennai and Kolkata. In addition, this paper also examines the effect of socio-economic and demographic factors on self-reported reproductive health problems. Bi-variate and multivariate regression have been applied to achieve the proposed objectives. Study is based on National Family Health Survey 2015-16 data. The analysis shows that the prevalence of any reproductive health problem among women is the highest in Mumbai followed by Delhi, Chennai, and Kolkata. A bulk of women in all four metro cities has reported abdominal pain, itching and burning sensation as the major problems while urinating. However, in spite of the high prevalence of reproductive health problems, a huge proportion of such women in all these cities do not seek any advice or treatment for these problems. This study also investigates determinants that affect the prevalence of reproductive health problem to policy makers plan for proper interventions for improving women’s reproductive health.

Keywords: reproductive health, India, national family health survey-4, city

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1041 Modeling Waiting and Service Time for Patients: A Case Study of Matawale Health Centre, Zomba, Malawi

Authors: Moses Aron, Elias Mwakilama, Jimmy Namangale

Abstract:

Spending more time on long queues for a basic service remains a common challenge to most developing countries, including Malawi. For health sector in particular, Out-Patient Department (OPD) experiences long queues. This puts the lives of patients at risk. However, using queuing analysis to under the nature of the problems and efficiency of service systems, such problems can be abated. Based on a kind of service, literature proposes different possible queuing models. However, unlike using generalized assumed models proposed by literature, use of real time case study data can help in deeper understanding the particular problem model and how such a model can vary from one day to the other and also from each case to another. As such, this study uses data obtained from one urban HC for BP, Pediatric and General OPD cases to investigate an average queuing time for patients within the system. It seeks to highlight the proper queuing model by investigating the kind of distributions functions over patient’s arrival time, inter-arrival time, waiting time and service time. Comparable with the standard set values by WHO, the study found that patients at this HC spend more waiting times than service times. On model investigation, different days presented different models ranging from an assumed M/M/1, M/M/2 to M/Er/2. As such, through sensitivity analysis, in general, a commonly assumed M/M/1 model failed to fit the data but rather an M/Er/2 demonstrated to fit well. An M/Er/3 model seemed to be good in terms of measuring resource utilization, proposing a need to increase medical personnel at this HC. However, an M/Er/4 showed to cause more idleness of human resources.

Keywords: health care, out-patient department, queuing model, sensitivity analysis

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1040 Enhancement in Antimicrobial and Antioxidant Activity of Cuminum cyminum L. through Niosome Nanocarries

Authors: Fatemeh Haghiralsadat, Mohadese Hashemi, Elham Akhoundi Kharanaghi, Mojgan Yazdani, Mahboobe Sharafodini, Omid Javani

Abstract:

Niosomes are colloidal particles formed from the self-assembly of non-ionic surfactants in aqueous medium resulting in closed bilayer structures. As a consequence of this hydrophilic and hydrophobic structure, niosomes have the capacity to entrap compounds of different solubilities. Niosomes are promising vehicle for drug delivery which protect sensitive drugs and improve the therapeutic index of drugs by restricting their action to target cells. Essential oils are complex mixtures of volatile compounds such as terpenoids, phenol-derived aromatic components that have been used for many biological properties including bactericidal, fungicidal, insecticidal, antioxidant, anti-tyrosinase and other medicinal properties. Encapsulation of essential oils in niosomes can be an attractive method to overcome their limitation such as volatility, easily decomposition by heat, humidity, light, or oxygen. Cuminum cyminum L. (Cumin) is an aromatic plant included in the Apiaceae family and is used to flavor foods, added to fragrances, and for medical preparations which is indigenous to Egypt, the Mediterranean region, Iran and India. The major components of the Cumin oil were reported as cuminaldehyde, γ -terpinene, β-pinene, p-cymene, p-mentha-1, 3-dien-7-al, and p-mentha-1, 4-dien-7-al which provide the antimicrobial and antioxidant activity. The aim of this work was to formulate Cumin essential oil-loaded niosomes to improve water solubility of natural product and evaluate its physico-chemical features and stability. Cumin oil was obtained through steam distillation using a clevenger-type apparatus and GC/MS was applied to identify the main components of the essential oil. Niosomes were prepared by using thin film hydration method and nanoparticles were characterized for particle size, dispersity index, zeta potential, encapsulation efficiency, in vitro release, and morphology.

Keywords: Cuminum cyminum L., Cumin, niosome, essential oil, encapsulation

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1039 Mob Justice in Ghana: Implication for Peace

Authors: Ishaq Alhassan Meriga

Abstract:

This study examined the phenomenon of mob violence and its implication for peace in Ghana. The study used the archival study of media reports and content analysis of other secondary data as well as eyewitness accounts. The study examined trends and patterns of vigilante violence within the Ghanaian context. Results showed a considerable increase in the occurrence of mob violence within the last 10 years. Theft and robbery emerged as the most frequently suspected crimes for which victims were attacked, while the LGBT community is not left out. Cases of mob violence were most frequently reported in urban areas. This study has shown that the patterns, scope, nature, and implication of mob justice in Ghana are fairly and comparatively similar to those found in other parts of Africa and the globe. Mob violence is identified as undermining the rule of law and thereby infringing on the fundamental human rights of the victims. It is confirmed to have a cycle of effects that is an impediment to the peace of the country. The study underscores the implications of mob violence in terms of disdaining human life and dignity, revisiting our justice systems and punishment procedures, resourcing, and empowering law enforcers to fight the menace of vigilantism. First, the archival study had a limitation regarding missing data. The majority of the cases used for the study lack information mostly on perpetrators and the steps taken by public authorities and security agencies after reports of a mob attack have been lodged with them. The study recommends for further research to be undertaken on the perpetrators and survivors of mob actions in order to get a holistic understanding of the phenomenon. This will give a more comprehensive view of the issue of mob violence in Ghana. From the findings, it can be concluded that mob justice is a social canker in Ghanaian communities, which has a great impact on the peace of the country.

Keywords: LGBT, mob justice, peace, vigilantism

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1038 Research on the Evolutionary Character of Capital in Rural Areas and Counter-Measure of Planning

Authors: Han Song, Tingting Wei, Dong Chen

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The combination of capital and rural areas in China has shown its great significance in promoting urban-rural integration and new-style urbanization, enhancing regional capacity for sustainable rural development and optimizing human settlement environment. The purpose of this study is to find capital operation mechanism in rural area and rural planning guidance in China. Based on case studies in Chinese rural areas, two types of capital operation mechanism in rural areas are summed up: intervention in the field of agriculture promoting the upgrading and innovation of agricultural industry chain, intervention in rural life and leisure areas updating rural connotation and form. In the light of experiences in Japan and Taiwan, it is proposed that government's norms and guidance, rural investment intensity and rural self-organization are three important factors for capital to drive rural development. It is also found that the unique land tenure and rural governance tradition are two important factors effecting the combination of capital and rural regions in China, which requires full attention in rational policy-making and rural planning. It comes to a conclusion as four directions of the overall reform of the rural planning: targeting at enhancing the viability of rural and sustainable capacity, encouraging differences in investment incentives and planning policies, providing land usage in the rural areas with planning support and reforming the village system. Directional guidance is also made for different types of capital investments, suggesting that capital should be rooted in agriculture and rural land to benefit farmers and update human settlements.

Keywords: capital, rural areas, rural planning, rural governance

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1037 The Moment of Departure: Redefining Self and Space in Literacy Activism

Authors: Sofie Dewayani, Pratiwi Retnaningdyah

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Literacy practice is situated within the identity enactment in a particular time and space. The literacy practices in public places, ranging from city parks, urban slums to city roads are meeting places of discursive practices produced by dynamic interactions, and sometimes contestations, of social powers and capitals. The present paper examines the ways the literacy activists construct their sense of space in attempts to develop possibilities for literacy programs as they are sent to work with marginalized communities far away from their hometowns in Indonesia. In particular, this paper analyzes the activists’ reflections of identity enactment - othering, familiarity, and sense of comfort - as they are trying to make meaning of the communities’ literacy capitals and practices in the process of adapting with the communities. Data collected for this paper were travel diaries - serving as literacy narratives - obtained from a literacy residency program sponsored by the Indonesian Ministry of Education and Culture. The residency program itself involved 30 youths (18 to 30 years old) to work with marginalized communities in literacy activism programs. This paper analyzes the written narratives of four focal participants using Bakhtin’s chronotopes - the configurations of time and space - that figure into the youth’s meaning-making of literacy as well as their exercise of power and identity. Follow-up interviews were added to enrich the analysis. The analysis considers the youth’s ‘moment of departure’ a critical point in their reconstructions of self and space. This paper expands the discussions of literacy discourse and spatiality while lending its supports to literacy activism in highly diverse multicultural settings.

Keywords: chronotopes, discourse, identity, literacy activism

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1036 High-Pressure Steam Turbine for Medium-Scale Concentrated Solar Power Plants

Authors: Ambra Giovannelli, Coriolano Salvini

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Many efforts have been spent in the design and development of Concentrated Solar Power (CPS) Plants worldwide. Most of them are for on-grid electricity generation and they are large plants which can benefit from the economies of scale. Nevertheless, several potential applications for Small and Medium-Scale CSP plants can be relevant in the industrial sector as well as for off-grid purposes (i.e. in rural contexts). In a wide range of industrial processes, CSP technologies can be used for heat generation replacing conventional primary sources. For such market, proven technologies (usually hybrid solutions) already exist: more than 100 installations, especially in developing countries, are in operation and performance can be verified. On the other hand, concerning off-grid applications, solar technologies are not so mature. Even if the market offers a potential deployment of such systems, especially in countries where the access to grid is strongly limited, optimized solutions have not been developed yet. In this context, steam power plants can be taken into consideration for medium scale installations, due to the recent results achieved with direct steam generation systems based on paraboloidal dish or Fresnel lens solar concentrators. Steam at 4.0-4.5 MPa and 500°C can be produced directly by means of innovative solar receivers (some prototypes already exist). Although it could seem a promising technology, presently, steam turbines commercially available do not cover the required cycle specifications. In particular, while low-pressure turbines already exist on the market, high-pressure groups, necessary for the abovementioned applications, are not available. The present paper deals with the preliminary design of a high-pressure steam turbine group for a medium-scale CSP plant (200-1000 kWe). Such a group is arranged in a single geared package composed of four radial expander wheels. Such wheels have been chosen on the basis of automotive turbocharging technology and then modified to take the new requirements into account. Results related to the preliminary geometry selection and to the analysis of the high-pressure turbine group performance are reported and widely discussed.

Keywords: concentrated solar power (CSP) plants, steam turbine, radial turbine, medium-scale power plants

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1035 Remittances and Water Access: A Cross-Sectional Study of Sub Saharan Africa Countries

Authors: Narges Ebadi, Davod Ahmadi, Hiliary Monteith, Hugo Melgar-Quinonez

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Migration cannot necessarily relieve pressure on water resources in origin communities, and male out-migration can increase the water management burden of women. However, inflows of financial remittances seem to offer possibilities of investing in improving drinking-water access. Therefore, remittances may be an important pathway for migrants to support water security. This paper explores the association between water access and the receipt of remittances in households in sub-Saharan Africa. Data from round 6 of the 'Afrobarometer' surveys in 2016 were used (n= 49,137). Descriptive, bivariate and multivariate statistical analyses were carried out in this study. Regardless of country, findings from descriptive analyses showed that approximately 80% of the respondents never received remittance, and 52% had enough clean water. Only one-fifth of the respondents had piped water supply inside the house (19.9%), and approximately 25% had access to a toilet inside the house. Bivariate analyses revealed that even though receiving remittances was significantly associated with water supply, the strength of association was very weak. However, other factors such as the area of residence (rural vs. urban), cash income frequencies, electricity access, and asset ownership were strongly associated with water access. Results from unadjusted multinomial logistic regression revealed that the probability of having no access to piped water increased among remittance recipients who received financial support at least once a month (OR=1.324) (p < 0.001). In contrast, those not receiving remittances were more likely to regularly have a water access concern (OR=1.294) (p < 0.001), and not have access to a latrine (OR=1.665) (p < 0.001). In conclusion, receiving remittances is significantly related to water access as the strength of odds ratios for socio-demographic factors was stronger.

Keywords: remittances, water access, SSA, migration

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1034 A Comparative Study of the Techno-Economic Performance of the Linear Fresnel Reflector Using Direct and Indirect Steam Generation: A Case Study under High Direct Normal Irradiance

Authors: Ahmed Aljudaya, Derek Ingham, Lin Ma, Kevin Hughes, Mohammed Pourkashanian

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Researchers, power companies, and state politicians have given concentrated solar power (CSP) much attention due to its capacity to generate large amounts of electricity whereas overcoming the intermittent nature of solar resources. The Linear Fresnel Reflector (LFR) is a well-known CSP technology type for being inexpensive, having a low land use factor, and suffering from low optical efficiency. The LFR was considered a cost-effective alternative option to the Parabolic Trough Collector (PTC) because of its simplistic design, and this often outweighs its lower efficiency. The LFR has been found to be a promising option for directly producing steam to a thermal cycle in order to generate low-cost electricity, but also it has been shown to be promising for indirect steam generation. The purpose of this important analysis is to compare the annual performance of the Direct Steam Generation (DSG) and Indirect Steam Generation (ISG) of LFR power plants using molten salt and other different Heat Transfer Fluids (HTF) to investigate their technical and economic effects. A 50 MWe solar-only system is examined as a case study for both steam production methods in extreme weather conditions. In addition, a parametric analysis is carried out to determine the optimal solar field size that provides the lowest Levelized Cost of Electricity (LCOE) while achieving the highest technical performance. As a result of optimizing the optimum solar field size, the solar multiple (SM) is found to be between 1.2 – 1.5 in order to achieve as low as 9 Cent/KWh for the direct steam generation of the linear Fresnel reflector. In addition, the power plant is capable of producing around 141 GWh annually and up to 36% of the capacity factor, whereas the ISG produces less energy at a higher cost. The optimization results show that the DSG’s performance overcomes the ISG in producing around 3% more annual energy, 2% lower LCOE, and 28% less capital cost.

Keywords: concentrated solar power, levelized cost of electricity, linear Fresnel reflectors, steam generation

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1033 Continuity of Place-Identity: Identifying Regional Components of Kerala Architecture through 1805-1950

Authors: Manoj K. Kumar, Deepthi Bathala

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Man has the need to know and feel as a part of the historical continuum and it is this continuum that reinforces his identity. Architecture and the built environment contribute to this identity as established by the various identity theories exploring the relationship between the two. Architecture which is organic has been successful in maintaining a continuum of identity until the advent of globalization when the world saw a drastic shift to architecture of ‘placelessness’. The answer to the perfect synthesis of ‘universalization’ and ‘regionalism’ is an ongoing quest. However, history has established a smooth transition from vernacular to colonial to modern unlike the architecture of today. The traditional Kerala architecture has evolved from the tropical climate, geography, local needs, materials, skills and foreign influences. It is unique in contrast to the architecture of the neighboring states as a result of the geographical barriers however influenced by the architecture of the Orient due to trade relations. Through 1805 to 1950, the European influence on the architecture of Kerala resulted in the emergence of the colonial style which managed to establish a continuum of the traditional architecture. The paper focuses on the identification of the components of architecture that established the continuity of place-identity in the architecture of Kerala and examines the transition from the traditional Kerala architecture to colonial architecture during the colonial period. Visual surveys based on the principles of urban design, cognitive mapping, typology analysis followed by the strong understanding of the morphological and built environment along with the matrix method are the research tools used. The understanding of these components of continuity can be useful in creating buildings which people can relate to in the present day. South-Asia shares the history of colonialism and the understanding of these components can pave the way for further research on how to establish a regional identity in the era of globalization.

Keywords: colonial, identity, place, regional

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1032 Geometry, the language of Manifestation of Tabriz School’s Mystical Thoughts in Architecture (Case Study: Dome of Soltanieh)

Authors: Lida Balilan, Dariush Sattarzadeh, Rana Koorepaz

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In the Ilkhanid era, the mystical school of Tabriz manifested itself as an art school in various aspects, including miniatures, architecture, urban planning and design, simultaneously with the expansion of the many sciences of its time. In this era, mysticism, both in form and in poetry and prose, as well as in works of art reached its peak. Mysticism, as an inner belief and thought, brought the audience to the artistic and aesthetical view using allegorical and symbolic expression of the religion and had a direct impact on the formation of the intellectual and cultural layers of the society. At the same time, Mystic school of Tabriz could create a symbolic and allegorical language to create magnificent works of architecture with the expansion of science in various fields and using various sciences such as mathematics, geometry, science of numbers and by Abjad letters. In this era, geometry is the middle link between mysticism and architecture and it is divided into two categories, including intellectual and sensory geometry and based on its function. Soltaniyeh dome is one of the prominent buildings of the Tabriz school with the shrine land use. In this article, information is collected using a historical-interpretive method and the results are analyzed using an analytical-comparative method. The results of the study suggest that the designers and builders of the Soltaniyeh dome have used shapes, colors, numbers, letters and words in the form of motifs, geometric patterns as well as lines and writings in levels and layers ranging from plans to decorations and arrays for architectural symbolization and encryption to express and transmit mystical ideas.

Keywords: geometry, Tabriz school, mystical thoughts, dome of Soltaniyeh

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1031 The Sensitivity of Electrical Geophysical Methods for Mapping Salt Stores within the Soil Profile

Authors: Fathi Ali Swaid

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Soil salinization is one of the most hazardous phenomenons accelerating the land degradation processes. It either occurs naturally or is human-induced. High levels of soil salinity negatively affect crop growth and productivity leading land degradation ultimately. Thus, it is important to monitor and map soil salinity at an early stage to enact effective soil reclamation program that helps lessen or prevent future increase in soil salinity. Geophysical method has outperformed the traditional method for assessing soil salinity offering more informative and professional rapid assessment techniques for monitoring and mapping soil salinity. Soil sampling, EM38 and 2D conductivity imaging have been evaluated for their ability to delineate and map the level of salinity variations at Second Ponds Creek. The three methods have shown that the subsoil in the study area is saline. Salt variations were successfully observed under either method. However, EM38 reading and 2D inversion data show a clear spatial structure comparing to EC1:5 of soil samples in spite of that all soil samples, EM38 and 2D imaging were collected from the same location. Because EM38 readings and 2D imaging data are a weighted average of electrical soil conductance, it is more representative of soil properties than the soil samples method. The mapping of subsurface soil at the study area has been successful and the resistivity imaging has proven to be an advantage. The soil salinity analysis (EC1:5) correspond well to the true resistivity bringing together a good result of soil salinity. Soil salinity clearly indicated by previous investigation EM38 have been confirmed by the interpretation of the true resistivity at study area.

Keywords: 2D conductivity imaging, EM38 readings, soil salinization, true resistivity, urban salinity

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1030 Technology of Gyro Orientation Measurement Unit (Gyro Omu) for Underground Utility Mapping Practice

Authors: Mohd Ruzlin Mohd Mokhtar

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At present, most operators who are working on projects for utilities such as power, water, oil, gas, telecommunication and sewerage are using technologies e.g. Total station, Global Positioning System (GPS), Electromagnetic Locator (EML) and Ground Penetrating Radar (GPR) to perform underground utility mapping. With the increase in popularity of Horizontal Directional Drilling (HDD) method among the local authorities and asset owners, most of newly installed underground utilities need to use the HDD method. HDD method is seen as simple and create not much disturbance to the public and traffic. Thus, it was the preferred utilities installation method in most of areas especially in urban areas. HDDs were installed much deeper than exiting utilities (some reports saying that HDD is averaging 5 meter in depth). However, this impacts the accuracy or ability of existing underground utility mapping technologies. In most of Malaysia underground soil condition, those technologies were limited to maximum of 3 meter depth. Thus, those utilities which were installed much deeper than 3 meter depth could not be detected by using existing detection tools. The accuracy and reliability of existing underground utility mapping technologies or work procedure were in doubt. Thus, a mitigation action plan is required. While installing new utility using Horizontal Directional Drilling (HDD) method, a more accurate underground utility mapping can be achieved by using Gyro OMU compared to existing practice using e.g. EML and GPR. Gyro OMU is a method to accurately identify the location of HDD thus this mapping can be used or referred to avoid those cost of breakdown due to future HDD works which can be caused by inaccurate underground utility mapping.

Keywords: Gyro Orientation Measurement Unit (Gyro OMU), Horizontal Directional Drilling (HDD), Ground Penetrating Radar (GPR), Electromagnetic Locator (EML)

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1029 The Counselling Practice of School Social Workers in Swedish Elementary Schools - A Focus Group Study

Authors: Kjellgren Maria, Lilliehorn Sara, Markström Urban

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This article describes the counselling practice of school social workers (SSWs) with individual children. SSWs work in the school system’s pupil health team, whose primary task is health promotion and prevention. The work of SSWs is about helping children and adolescents who, for various reasons, suffer from mental ill-health, school absenteeism, or stress that make them unable to achieve their intended goals. SSWs preferably meet these children in individual counselling sessions. The aim of this article is to describe and analyse SSWs’ experience of counselling with children and to examine the characteristics of counselling practice. The data collection was conducted through four semi-structured focus group interviews with a total of 22 SSWs in four different regions in Sweden. SSWs provide counselling to children in order to bring about improved feelings or behavioural changes. It can be noted that SSWs put emphasis on both the counselling process and the alliance with the child. The interviews showed a common practice among SSWs regarding the structure of the counselling sessions, with certain steps and approaches being employed. However, the specific interventions differed and were characterised by an eclectic standpoint in which SSWs utilise a broad repertoire of therapeutic schools and techniques. Furthermore, a relational perspective emerged as a most prominent focus for the SSWs by re-emerging throughout the material. We believe that SSWs could benefit from theoretical perspectives on ‘contextual model’ and ‘attachment theory’ as ‘models of the mind’. Being emotionally close to the child and being able to follow their development requires a lot from SSWs, as both professional caregivers and as “safe havens”.

Keywords: school social conselling, school social workers, contextual model, attachment thory

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1028 Hardy Type Inequalities of Two-Dimensional on Time Scales via Steklov Operator

Authors: Wedad Albalawi

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The mathematical inequalities have been the core of mathematical study and used in almost all branches of mathematics as well in various areas of science and engineering. The inequalities by Hardy, Littlewood and Polya were the first significant composition of several science. This work presents fundamental ideas, results and techniques and it has had much influence on research in various branches of analysis. Since 1934, various inequalities have been produced and studied in the literature. Furthermore, some inequalities have been formulated by some operators; in 1989, weighted Hardy inequalities have been obtained for integration operators. Then, they obtained weighted estimates for Steklov operators that were used in the solution of the Cauchy problem for the wave equation. They were improved upon in 2011 to include the boundedness of integral operators from the weighted Sobolev space to the weighted Lebesgue space. Some inequalities have been demonstrated and improved using the Hardy–Steklov operator. Recently, a lot of integral inequalities have been improved by differential operators. Hardy inequality has been one of the tools that is used to consider integrity solutions of differential equations. Then dynamic inequalities of Hardy and Coposon have been extended and improved by various integral operators. These inequalities would be interesting to apply in different fields of mathematics (functional spaces, partial differential equations, mathematical modeling). Some inequalities have been appeared involving Copson and Hardy inequalities on time scales to obtain new special version of them. A time scale is defined as a closed subset contains real numbers. Then the inequalities of time scales version have received a lot of attention and has had a major field in both pure and applied mathematics. There are many applications of dynamic equations on time scales to quantum mechanics, electrical engineering, neural networks, heat transfer, combinatorics, and population dynamics. This study focuses on double integrals to obtain new time-scale inequalities of Copson driven by Steklov operator. They will be applied in the solution of the Cauchy problem for the wave equation. The proof can be done by introducing restriction on the operator in several cases. In addition, the obtained inequalities done by using some concepts in time scale version such as time scales calculus, theorem of Fubini and the inequality of H¨older.

Keywords: time scales, inequality of Hardy, inequality of Coposon, Steklov operator

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1027 Modeling and Simulation of Multiphase Evaporation in High Torque Low Speed Diesel Engine

Authors: Ali Raza, Rizwan Latif, Syed Adnan Qasim, Imran Shafi

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Diesel engines are most efficient and reliable in terms of efficiency, reliability, and adaptability. Most of the research and development up till now have been directed towards High Speed Diesel Engine, for Commercial use. In these engines, objective is to optimize maximum acceleration by reducing exhaust emission to meet international standards. In high torque low speed engines, the requirement is altogether different. These types of engines are mostly used in Maritime Industry, Agriculture Industry, Static Engines Compressors Engines, etc. On the contrary, high torque low speed engines are neglected quite often and are eminent for low efficiency and high soot emissions. One of the most effective ways to overcome these issues is by efficient combustion in an engine cylinder. Fuel spray dynamics play a vital role in defining mixture formation, fuel consumption, combustion efficiency and soot emissions. Therefore, a comprehensive understanding of the fuel spray characteristics and atomization process in high torque low speed diesel engine is of great importance. Evaporation in the combustion chamber has a rigorous effect on the efficiency of the engine. In this paper, multiphase evaporation of fuel is modeled for high torque low speed engine using the CFD (computational fluid dynamics) codes. Two distinct phases of evaporation are modeled using modeling soft wares. The basic model equations are derived from the energy conservation equation and Naiver-Stokes equation. O’Rourke model is used to model the evaporation phases. The results obtained showed a generous effect on the efficiency of the engine. Evaporation rate of fuel droplet is increased with the increase in vapor pressure. An appreciable reduction in size of droplet is achieved by adding the convective heat effects in the combustion chamber. By and large, an overall increase in efficiency is observed by modeling distinct evaporation phases. This increase in efficiency is due to the fact that droplet size is reduced and vapor pressure is increased in the engine cylinder.

Keywords: diesel fuel, CFD, evaporation, multiphase

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1026 The Effect of Oil Pollution on Marine Microbial Populations in Israeli Coastal Waters

Authors: Yael Shai, Dror L. Angel, Dror Zurel, Peleg Astrahan, Maxim Rubin-Blum, Eyal Rahav

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The high demand for oil and its by-products is symptomatic of the 21st century and occasionally leads to oil spills and pollution of coastal waters. Marine oil pollution may originate from a variety of sources -urban runoff, tanker cleaning, drilling activities, and oil spills. These events may release large amounts of highly toxic polycyclic aromatic hydrocarbons (PAHs) and other pollutants to coastal water, thereby threatening local marine life. Here, we investigated the effects of crude oil on the temporal dynamics of phytoplankton and heterotrophic bacteria in Israeli coastal waters. To this end, we added crude oil (500 µm thick layer, with and without additional nutrients; NO₃ and PO₄) to mesocosms (1m³ bags) containing oligotrophic surface coastal water collected near Haifa during summer and winter. Changes in phytoplankton biomass, activity and diversity were monitored daily for 5-6 days. Our results demonstrate that crude oil addition resulted in a pronounced decrease in phytoplankton biomass and production rates, while heterotrophic bacterial production increased significantly. Importantly, a few days post addition we found that the oil-degrading bacteria, Oleibacter sp. and Oleispira sp. appeared in the mesocosms and that the addition of nutrients (along with the crude oil) further increased this trend. This suggests that oil-degrading bacteria may be NO₃ and PO₄ limited in Israeli coastal waters. The results of this study should enable us to establish improved science-based environmental policy with respect to handling crude oil pollution in this region.

Keywords: heterotrophic bacteria, nutrients, mesocosm, oil pollution, oligotrophic, phytoplankton

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1025 The Effects of Cooling during Baseball Games on Perceived Exertion and Core Temperature

Authors: Chih-Yang Liao

Abstract:

Baseball is usually played outdoors in the warmest months of the year. Therefore, baseball players are susceptible to the influence of the hot environment. It has been shown that hitting performance is increased in games played in warm weather, compared to in cold weather, in Major League Baseball. Intermittent cooling during sporting events can prevent the risk of hyperthermia and increase endurance performance. However, the effects of cooling during baseball games played in a hot environment are unclear. This study adopted a cross-over design. Ten Division I collegiate male baseball players in Taiwan volunteered to participate in this study. Each player played two simulated baseball games, with one day in between. Five of the players received intermittent cooling during the first simulated game, while the other five players received intermittent cooling during the second simulated game. The participants were covered in neck and forehand regions for 6 min with towels that were soaked in icy salt water 3 to 4 times during the games. The participants received the cooling treatment in the dugout when they were not on the field for defense or hitting. During the 2 simulated games, the temperature was 31.1-34.1°C and humidity was 58.2-61.8%, with no difference between the two games. Ratings of perceived exertion, thermal sensation, tympanic and forehead skin temperature immediately after each defensive half-inning and after cooling treatments were recorded. Ratings of perceived exertion were measured using the Borg 10-point scale. The thermal sensation was measured with a 6-point scale. The tympanic and skin temperature was measured with infrared thermometers. The data were analyzed with a two-way analysis of variance with repeated measurement. The results showed that intermitted cooling significantly reduced ratings of perceived exertion and thermal sensation. Forehead skin temperature was also significantly decreased after cooling treatments. However, the tympanic temperature was not significantly different between the two trials. In conclusion, intermittent cooling in the neck and forehead regions was effective in alleviating the perceived exertion and heat sensation. However, this cooling intervention did not affect the core temperature. Whether intermittent cooling has any impact on hitting or pitching performance in baseball players warrants further investigation.

Keywords: baseball, cooling, ratings of perceived exertion, thermal sensation

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1024 Crustal Deformation Study across the Chite Fault Using GPS Measurements in North East India along the Indo Burmese Arc

Authors: Malsawmtluanga, J. Malsawma, R. P. Tiwari, V. K. Gahalaut

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North East India is seismically one of the six most active regions of the world. It is placed in Zone V, the highest zone in the seismic zonation of India. It lies at the junction of Himalayan arc to the north and the Burmese arc to the east. The region has witnessed at least 18 large earthquakes including two great earthquakes Shillong (1987, M=8.7) and the Assam Tibet border (1950, M=8.7).The prominent Chite fault lies at the heart of Aizawl, the capital of Mizoram state and this hilly city is the home to about 2 million people. Geologically the area is a part of the Indo-Burmese Wedge and is prone to natural and man-made disasters. Unplanned constructions and urban dwellings on a rapid scale have lead to numerous unsafe structures adversely affecting the ongoing development and welfare projects of the government and they pose a huge threat for earthquakes. Crustal deformation measurements using campaign mode GPS were undertaken across this fault. Campaign mode GPS data were acquired and were processed with GAMIT-GLOBK software. The study presents the current velocity estimates at all the sites in ITRF 2008 and also in the fixed Indian reference frame. The site motion showed that there appears to be no differential motion anywhere across the fault area, thus confirming presently the fault is neither accumulating strain nor slipping aseismically. From the geological and geomorphological evidence, supported by geodetic measurements, lack of historic earthquakes, the Chite fault favours aseismic behaviour in this part of the Indo Burmese Arc (IBA).

Keywords: Chite fault, crustal deformation, geodesy, GPS, IBA

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1023 Two-Level Separation of High Air Conditioner Consumers and Demand Response Potential Estimation Based on Set Point Change

Authors: Mehdi Naserian, Mohammad Jooshaki, Mahmud Fotuhi-Firuzabad, Mohammad Hossein Mohammadi Sanjani, Ashknaz Oraee

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In recent years, the development of communication infrastructure and smart meters have facilitated the utilization of demand-side resources which can enhance stability and economic efficiency of power systems. Direct load control programs can play an important role in the utilization of demand-side resources in the residential sector. However, investments required for installing control equipment can be a limiting factor in the development of such demand response programs. Thus, selection of consumers with higher potentials is crucial to the success of a direct load control program. Heating, ventilation, and air conditioning (HVAC) systems, which due to the heat capacity of buildings feature relatively high flexibility, make up a major part of household consumption. Considering that the consumption of HVAC systems depends highly on the ambient temperature and bearing in mind the high investments required for control systems enabling direct load control demand response programs, in this paper, a recent solution is presented to uncover consumers with high air conditioner demand among large number of consumers and to measure the demand response potential of such consumers. This can pave the way for estimating the investments needed for the implementation of direct load control programs for residential HVAC systems and for estimating the demand response potentials in a distribution system. In doing so, we first cluster consumers into several groups based on the correlation coefficients between hourly consumption data and hourly temperature data using K-means algorithm. Then, by applying a recent algorithm to the hourly consumption and temperature data, consumers with high air conditioner consumption are identified. Finally, demand response potential of such consumers is estimated based on the equivalent desired temperature setpoint changes.

Keywords: communication infrastructure, smart meters, power systems, HVAC system, residential HVAC systems

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1022 A Multiple Case Study of How Bilingual-Bicultural Teachers' Language Shame and Loss Affects Teaching English Language Learners

Authors: Lisa Winstead, Penny Congcong Wang

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This two-year multiple case study of eight Spanish-English speaking teachers explores bilingual-bicultural Latino teachers’ lived experiences as English Language Learners and, more recently, as adult teachers who work with English Language Learners in mainstream schools. Research questions explored include: How do bilingual-bicultural teachers perceive their native language use and sense of self within society from childhood to adulthood? Correspondingly, what are bilingual teachers’ perceptions of how their own language learning experience might affect teaching students of similar linguistic and cultural backgrounds? This study took place in an urban area in the Pacific Southwest of the United States. Participants were K-8 teachers and enrolled in a Spanish-English bilingual authorization program. Data were collected from journals, focus group interviews, field notes, and class artifacts. Within case and cross-case analysis revealed that the participants were shamed about their language use as children which contributed to their primary language loss. They similarly reported how experiences of mainstream educator and administrator language shaming invalidated their ability to provide support for Latino heritage ELLs, despite their bilingual-bicultural expertise. However, participants reported that counter-narratives from the bilingual authorization program, parents, community and church organizations, and cultural responsive teachers were effective in promoting their language retention, pride, and feelings of well-being.

Keywords: teacher education, bilingual education, English language learners, emergent bilinguals, social justice, language shame, language loss, translanguaging

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1021 Assessing Walkability in New Cities around Cairo

Authors: Lobna Ahmed Galal

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Modal integration has given minimal consideration in cities of developing countries, as well as the declining dominance of public transport, and predominance of informal transport, the modal share of informal taxis in greater Cairo has increased from 6% in 1987 to 37% in 2001 and this has since risen even higher, informal and non-motorized modes of transport acting as a gap filler by feeding other modes of transport, not by design or choice, but often by lack of accessible and affordable public transport. Yet non-motorized transport is peripheral, with minimal priority in urban planning and investments, lacking of strong polices to support non-motorized transport, for authorities development is associated with technology and motorized transport, and promotion of non-motorized transport may be considered corresponding to development, as well as social stigma against non-motorized transport, as it is seen a travel mode for the poor. Cairo as a city of a developing country, has poor quality infrastructure for non-motorized transport, suffering from absence of dedicated corridors, and when existing they are often encroached for commercial purposes, widening traffic lanes at the expense of sidewalks, absence of footpaths, or being overcrowded, poor lighting, making walking unsafe and yet, lack of financial supply to such facilities as it is often considered beyond city capabilities. This paper will deal with the objective measuring of the built environment relating to walking, in some neighborhoods of new cities around Cairo, In addition to comparing the results of the objective measures of the built environment with the level of self-reported survey. The first paper's objective is to show how the index ‘walkability of community neighborhoods’ works in the contexts in neighborhoods of new cities around Cairo. The procedure of objective measuring is of a high potential to be carried out by using GIS.

Keywords: assessing, built environment, Cairo, walkability

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1020 Cultural Reflection within Contemporary Residential Interior in India

Authors: Icy Vinod Sanghvi

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In the light of rising modernism within the residential design industry, a significant growth of the western concepts of maximalism or minimalism is observed in the Indian housings. Although dynamism in design styles is natural due to the constant emergence of new innovations, it is imperative that local houses reflect cultural identity. This paper highlights the importance of ‘Indian Modernism’, and how to incorporate the same in residential design. Thus, helping the Indian culture to flourish and become a significant part of housing design in the future. A literature review was conducted to analyze and derive effective methods to build cultural value whilst catering to the urban and contemporary design industry. Alongside, a questionnaire survey was conducted to observe how the local houses are designed and to understand the preferences of people with regards to the design styles incorporated in their homes. In addition, their opinions on the excessive use of contemporary styles in home designs was recorded. The results of the same provided a better understanding of the local audience, their demands, and their willingness to adapt to contemporary designs. Studying color, materials, ornamentation, symbolism, detail, and structure offers an in-depth understanding of the essence of traditional Indian homes. These variables further provided effective solutions for design ideation and mockups for efficient traditional yet contemporary spaces. Design interventions like these can build a revolutionary set of practices that involve creating a balance between contemporary and traditional styles. The emergence of this synergy will not only make contemporary homes communicative but also allow India to compete within the global residential architecture industry with a strong foundation of its rich heritage.

Keywords: balance, contemporary design, cultural identity, Indian modernism

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1019 Laser - Ultrasonic Method for the Measurement of Residual Stresses in Metals

Authors: Alexander A. Karabutov, Natalia B. Podymova, Elena B. Cherepetskaya

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The theoretical analysis is carried out to get the relation between the ultrasonic wave velocity and the value of residual stresses. The laser-ultrasonic method is developed to evaluate the residual stresses and subsurface defects in metals. The method is based on the laser thermooptical excitation of longitudinal ultrasonic wave sand their detection by a broadband piezoelectric detector. A laser pulse with the time duration of 8 ns of the full width at half of maximum and with the energy of 300 µJ is absorbed in a thin layer of the special generator that is inclined relative to the object under study. The non-uniform heating of the generator causes the formation of a broadband powerful pulse of longitudinal ultrasonic waves. It is shown that the temporal profile of this pulse is the convolution of the temporal envelope of the laser pulse and the profile of the in-depth distribution of the heat sources. The ultrasonic waves reach the surface of the object through the prism that serves as an acoustic duct. At the interface ‚laser-ultrasonic transducer-object‘ the conversion of the most part of the longitudinal wave energy takes place into the shear, subsurface longitudinal and Rayleigh waves. They spread within the subsurface layer of the studied object and are detected by the piezoelectric detector. The electrical signal that corresponds to the detected acoustic signal is acquired by an analog-to-digital converter and when is mathematically processed and visualized with a personal computer. The distance between the generator and the piezodetector as well as the spread times of acoustic waves in the acoustic ducts are the characteristic parameters of the laser-ultrasonic transducer and are determined using the calibration samples. There lative precision of the measurement of the velocity of longitudinal ultrasonic waves is 0.05% that corresponds to approximately ±3 m/s for the steels of conventional quality. This precision allows one to determine the mechanical stress in the steel samples with the minimal detection threshold of approximately 22.7 MPa. The results are presented for the measured dependencies of the velocity of longitudinal ultrasonic waves in the samples on the values of the applied compression stress in the range of 20-100 MPa.

Keywords: laser-ultrasonic method, longitudinal ultrasonic waves, metals, residual stresses

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