• General Article

    Treatment of synthetic wastewater by using submerged attached growth media in continuous activated sludge reactor system
    Baker Nasser Saleh Al-dhawi, Shamsul Rahman Mohamed Kutty, Lavania Baloo, Najib Mohammed Yahya Almahbashi, Aiban Abdulhakim Saeed Ghaleb, Ahmad Hussaini Jagaba, Vicky Kumar and Anwar Ameen Hezam Saeed
    In wastewater treatment, biological treatment is considered the most efficient among all technologies. An attached-growth system in biological treatment is capable to … + READ MORE
    In wastewater treatment, biological treatment is considered the most efficient among all technologies. An attached-growth system in biological treatment is capable to provide more microorganisms attached to the fixed media and therefore increase the treatment efficiency. Moreover, the conventional wastewater treatment plants can not cope with Malaysian discharge limits. The purpose of this study is to enhance the efficiency of the treatment process using a submerged attached growth system incorporated with the conventional treatment system. Two parallel continuous flow-activated sludge systems treating synthetic wastewater were used. In Reactor A, POC was used as the submerged attached growth media while Reactor B was used as a control reactor. The bioreactor has a volume of 10 L. The studies were carried out at various influent flow rates of 5, 10, 15, 20, 25, and 30 L/d, and constant organic load rate OLR. The influent and effluent were sampled every two days. Parameters COD, MLSS, and MLVSS were monitored. Generally, COD was highly removed. The average removal of COD reached 96% for reactor A while 88% for reactor B. Overall, the system demonstrated higher treatment efficiency of COD removal. Kinetic models, Monod was applied. Monod was ideal for explaining the experimental data in terms of microbial growth parameters. Ks was obtained as 223.97 and 370 g/m3 for reactor A and B respectively, while (µmax) 0.25 and 0.16 per day with a correlation coefficient (R2) of 0.9435 and 0.8799, for reactor A and B, respectively. Therefore, the models can be used in designing a submerged attach growth system and consequently predict the bioreactor behaviour. - COLLAPSE
    31 March 2022
  • General Article

    A Review on fresh concrete, thermal conductivity, and permeability properties of concrete containing cockle shell
    Nabilla Mohamad, Khairunisa Muthusamy and Hanis Nadiah Ruslan
    Concrete has been used in large volumes for so many years. However, the use of concrete contributes to high cement and aggregate … + READ MORE
    Concrete has been used in large volumes for so many years. However, the use of concrete contributes to high cement and aggregate consumption, leading to an increase in material production. The consequences of these activities have been investigated, discussed, and proved that one of the causes of worsening global warming is due to the whole action from concrete industries. On other hand, many researchers found many alternative ways to prevent the extinction of non-renewable material by replacing current material in concrete or cement production with by-products. For example, cockle shell is an aquacultural by-product material that has been dumped after the consumers gain their meat. In this review paper, the new properties, workability, setting time, and other concrete properties containing cockle shells as cement and coarse aggregates such as thermal conductivity, permeability, and porosity, have been discussed. - COLLAPSE
    31 March 2022
  • General Article

    Modeling of octagonal concrete-filled double-skin steel tube stub columns under axial compression
    Shagea Alqawzai, Bo Yang, Belal Alsubari, Hayder Saadoon Abdulaali and Mohamed Elchalakani
    Octagonal concrete-filled double-skin steel tube (OCFDST) columns have drawn the attention of academia and building industries since they combined the advances of … + READ MORE
    Octagonal concrete-filled double-skin steel tube (OCFDST) columns have drawn the attention of academia and building industries since they combined the advances of higher confinement of circular CFDST columns and the better constructability options of square CFDST columns. Therefore, this paper investigates numerically the behavior of axially compressed OCFDST stub columns by the means of finite element analysis employing ABAQUS software. The accuracy of the developed finite element (FE) models was validated against the experimental results in terms of axial load-axial shortening curves and the ultimate strength of the test specimens. Then, subsequent parametric studies considering a wide range of outer parameters were performed by the verified FE model on the effects of various parameters including the thickness of outer steel tube (to), the thickness of inner steel tube (ti), the diameter of inner steel tube (Di) and type and arrangement of stiffening schemes. The numerically generated data were then used to evaluate the applicability of the design guidelines provided by existing European, North American, and Chinese provisions for composite columns. Based on the results, it was found that EC4 and modified EC4 formulas can safely be adopted to predict the design ultimate strength of OCFDST stub columns. AISC360 can also give a reasonable for non-stiffened specimens while, DBJ provides un-conservative predictions of ultimate strength when applied to non-stiffened OCFDST stub columns, while it can accurately calculate the ultimate strength of the OCFDST axial members with different stiffening schemes. - COLLAPSE
    31 March 2022
  • General Article

    Corrosion behavior of plain carbon steels under different heat treatment conditions in freely aerated 3.5% NaCl solution
    Prvan Kumar Katiyar, Rita Maurya and Prince Kumar Singh
    The present work discusses the effect of the role of interlamellar spacing, % pearlite and pearlite colony size on corrosion behaviour of … + READ MORE
    The present work discusses the effect of the role of interlamellar spacing, % pearlite and pearlite colony size on corrosion behaviour of plain carbon steels (0.002%C, 0.17%C, 0.43%C, and 0.7%C) under different heat treatment conditions using the electrochemical tests in freely aerated 3.5% NaCl solution. Hence, ultra-low carbon (~100% ferrite), low and medium carbon (ferrite-pearlite steels having ~ 32.74% and ~ 52.34% pearlite, respectively) and high carbon steels (~100% pearlite) have been used in annealed conditions. In addition, four different variants (coarse, medium, fine, and very fine) of pearlite steels have also been developed by suitable heat treatment (annealing, as-received, normalizing and force normalizing, respectively) processes using the 0.7% carbon steels to understand the role of interlamellar spacing and pearlite colony size on corrosion mechanisms of pearlitic steels. The corrosion rate of the steel was increased as the carbon content increased. However, the corrosion susceptibility of high carbon pearlite steels was increased in the following sequence: air-cooled - forced air-cooled - as-received - furnace annealed steel since variations in the finesse of the pearlite microstructure significantly alter the corrosion behaviour of pearlite steels. The normalized steel has shown the lowest corrosion susceptibility as compared to the force normalized steel due to the entanglement of cementite causing short-circuiting of the galvanic couples. The FE-SEM was used to examine the corroded specimens after polarization tests and found that the corrosion performance of the steels has mainly been guided by the joint effect of fraction of pearlite, interlamellar spacing, and pearlite colony size. - COLLAPSE
    31 March 2022
  • General Article

    Optimizing energy performance using silica aerogel material in building envelope
    Amr Soliman Elgohary, Haytham M. Elbadrawy and Shereen Khashaba
    Transparent or translucent insulation materials (TIMs) represent a new class of efficient materials with high thermal resistance that have an increased demand … + READ MORE
    Transparent or translucent insulation materials (TIMs) represent a new class of efficient materials with high thermal resistance that have an increased demand lately due to its environmentally friendly characteristics. An overview of the TIMs types as smart and green building’s envelope material, geometrical structure classification and properties will be illustrated. The research investigates the thermal energy and daylighting performance of the silica aerogel as a TIM material applied to the external envelope of an existing office building located in New Cairo - Egypt compared to its installed glazing base case. The results indicated that the application of silica aerogel to the glazing system can reduce the annual cooling loads by around 45% in a typical office building and reducing the spaces needed to create internal courtyards to enhance the natural lighting and reduce heat gain on the building. With respect to the existing envelope glazing, the reduction could exceed than that if the glazing system is replaced with a different thickness of silica aerogel, which affects the U value of the envelope and its thermal performance. Applying the TIMs to buildings’ envelope has a great impact concerning energy performance in the green building assessment tools i.e. LEED and GPRS. The drivers and barriers of applying the TIMs are discussed according to the potential Egyptian market base case. - COLLAPSE
    31 March 2022
  • General Article

    Architectural space changes during covid-19 pandemic
    Seda Simsek Tolacı, Ilker Erkan, Ali Gokaslan, Arzu Sahin, Ali Musab Kayhan, Munevver Sanlı and Elif Tugce Demir
    The pandemic caused people to spend more time in quarantine spaces (living spaces) than ever before and continuously interact with that space. … + READ MORE
    The pandemic caused people to spend more time in quarantine spaces (living spaces) than ever before and continuously interact with that space. With the emphasis that architectural designs affect subjective human experiences, it has been revealed by scientific studies that people need spaces that are intertwined with nature with gardens and terraces during periods like this. While these studies refer to the spatial configurations that will make individuals feel good psychologically, they also mention the buildings’ features such as their location, size, space quality, and comfort content. The main aim of running this paper is to identify the emotional state changes that occur in individuals during the quarantine period and to use these determinations in designs within the framework of the concept of “pandemic space,” a concept that emerged after the pandemic started. Seven hypotheses have been developed in this context. As method, a questionnaire consisting of 39 items designed to measure individuals’ emotional state changes was chosen. The meaningfulness of the hypotheses was questioned using the statistical values obtained as a result of the data analysis of the data collected from 1500 people. As a result of the study, several design approaches to pandemic spaces were put forward by trying to interpret this meaningfulness in terms of space. - COLLAPSE
    31 March 2022
  • General Article

    Impact of change in the design of naturally ventilated mass housing on life cycle energy and life cycle cost
    Aniket Sharma and Vandna Sharma
    In the state of Himachal Pradesh, Housing and Urban Development Authority is responsible for providing mass housing and has developed prototypic housing … + READ MORE
    In the state of Himachal Pradesh, Housing and Urban Development Authority is responsible for providing mass housing and has developed prototypic housing colonies using standard house designs at various locations in the state. This paper analyses the most common design of High-Income House, which has been used to develop mass housing at the case study location in District Hamirpur for its Life Cycle Energy and Life Cycle Cost. The study calculates the embodied energy of existing houses using material specifications, operational energy, total Life Cycle Energy and their respective costs for the life span of 50 years using Himachal Pradesh Schedule of Rates /market survey and Rs. 4.7/kWh (in INR) as operational energy cost. The study further identifies and compares the embodied energy, operational energy, Life Cycle Energy, and Life Cycle Cost of three other alternatives developed in the same plot area but with varying plot sizes and design characteristics such as house type, room sizes, built-up area, exposed surface area, volume, compactness ratio, exposed walls area, window area and Window to Wall Ratio (WWR) and finally, the impact of each factor on embodied, operational and Life Cycle Energy and their respective costs is determined. - COLLAPSE
    31 March 2022
  • General Article

    Sustainable rehabilitation of infrastructural mobility and the coastal built environment
    Francesca Ciampa
    In the context of the built environment and infrastructural mobility criticality in coastal cities, the research aims to establish a strategy for … + READ MORE
    In the context of the built environment and infrastructural mobility criticality in coastal cities, the research aims to establish a strategy for the sustainable rehabilitation of sites with a high density of tourism. In line with the European directives of Sustainable Development and Environmental Protection, the proposed strategy for the governance and management of the transformations of the built environment, aims to reconnect the identity and functional specificities of the territory at different scales. While respecting the historical and environmental values of the Sorrento Peninsula, the contribution experiments with a cross-analysis methodology, combining the systemic and performance approach with the need of urban transition. The results return a reticular and stratified model, which is operationally adaptable and replicable in other contexts. - COLLAPSE
    31 March 2022
  • General Article

    Study of thermal comfort in naturally ventilated educational buildings of hot and dry climate - A case study of Vadodara, Gujarat, India
    Sonal Gangrade and Aniket Sharma
    This study analyses the effect of environmental factors and use of adaptive methods on the occupants’ thermal comfort in naturally ventilated educational … + READ MORE
    This study analyses the effect of environmental factors and use of adaptive methods on the occupants’ thermal comfort in naturally ventilated educational buildings in the hot and dry climate of Vadodara. A questionnaire survey was conducted on 2674 occupants of six lecture halls of two buildings in September 2019 & January 2020 to record measures of activity, clothing level, and thermal preferences. A handheld anemometer was used to measure air temperature, relative humidity, and airspeed. It was found that the level of clothing was 0.37 to 0.69 clo in rainy and 0.52 to 1.1 clo in winter season respectively, showcasing adaptive behaviour of the occupant. The findings reveal that occupants were relatively more satisfied in January (winter season) than in September (rainy season). It is found that the thermal comfort range for RH ≥ 60%, in rainy and winter season is 27.4°C to 30.8°C (3.4°C) and is 24.1°C to 27.1°C (3°C), whereas for RH <60%, it is 27.4°C to 30.8°C (3.4°C) and 24.1°C to 27.1°C (3°C) respectively. It also establishes that the occupants preferred a slightly cooler temperature in the rainy season but preferred a slightly warmer temperature in the winter season. - COLLAPSE
    31 March 2022
Journal Informaiton International Journal of Sustainable Building Technology and Urban Development International Journal of Sustainable Building Technology and Urban Development
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