Search results for: gypsum partition walls

Authors: E. P. Bhowmik, R. Singh

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Certain materials casually thrown away as by-product household waste, such as used tea leaves, used coffee remnants, eggshells, peanut husks, coconut coir, unwanted paper, and pencil shavings- have scope in the hidden properties that they offer as recyclable raw ingredients. This paper aims to explore and experiment with the sustainable potential of such disposed wastes, obtained from domestic and commercial backgrounds, that could otherwise contribute to the field of interior design if mass-collected and repurposed. Research has been conducted on available recorded methods of mass-collection, storage, and processing of such materials by certain brands, designers, and researchers, as well as the various application and angles possible with regards to re-usage. A questionnaire survey was carried out to understand the willingness of the demographics for efforts of the mass collection and their openness to such unconventional materials for interiors. An experiment was also conducted where the selected waste ingredients were used to create small samples that could be used as decorative panels. Comparisons were made for properties like color, smell, texture, relative durability, and weight- and accordingly, applications were suggested. The experiment, therefore, helped to propose to recycle of the common household as a potential surface finish for floors, walls, and ceilings, and even founding material for furniture and decor accessories such as pottery and lamp shades; for non-structural application in both residential and commercial interiors. Common by-product wastes often see their ends at landfills- laymen unaware of their sustainable possibilities dispose of them. However, processing these waste materials and repurposing them by incorporating them into interiors would serve as a sustainable alternative to ethical dilemmas in the construction of interior design/architecture elements.

Keywords: interior materials, mass-collection, sustainable, waste recycle

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Authors: Krishna Prasad Maity, Narendra Tanty, Ananya Patra, V. Prasad

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Carbon nanotube (CNT) is a well-known material for very good electrical, thermal conductivity and high tensile strength. Because of that, it’s widely used in many fields like nanotechnology, electronics, optics, etc. In last two decades, polyaniline (PANI) with CNT and functionalized CNT (fCNT) have been promising materials in application of gas sensing, electromagnetic shielding, electrode of capacitor etc. So, the study of electrical conductivity of PANI/CNT and PANI/fCNT is important to understand the charge transport and interaction between PANI and CNT in the composite. It is observed that a transition in magnetoresistance (MR) with lowering temperature, increasing magnetic field and decreasing CNT percentage in CNT/PANI composite. Functionalization of CNT prevent the nanotube aggregation, improves interfacial interaction, dispersion and stabilized in polymer matrix. However, it shortens the length, breaks C-C sp² bonds and enhances the disorder creating defects on the side walls. We have studied electrical resistivity and MR in PANI with CNT and fCNT composites for different weight percentages down to the temperature 4.2K and up to magnetic field 5T. Resistivity increases significantly in composite at low temperature due to functionalization of CNT compared to only CNT. Interestingly a transition from negative to positive magnetoresistance has been observed when the filler is changed from pure CNT to functionalized CNT after a certain percentage (10wt%) as the effect of more disorder in fCNT/PANI composite. The transition of MR has been explained on the basis of polaron-bipolaron model. The long-range Coulomb interaction between two polarons screened by disorder in the composite of fCNT/PANI, increases the effective on-site Coulomb repulsion energy to form bipolaron which leads to change the sign of MR from negative to positive.

Keywords: coulomb interaction, magnetoresistance transition, polyaniline composite, polaron-bipolaron

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Authors: S. Hussain, N. Ahmad, S. Alam, M. Bezabhi, W. H. Hendriks, P. Yu, J. W. Cone

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The high content of lignin in cell walls is the major limiting factor in the digestion and utilisation of cereal crop residues by ruminants. The aim of this study was to evaluate the effectiveness of the white rot fungus, Pleurotus ostreatus (P. ostreatus), to degrade lignin and to enhance the rumen degradability of maize stover, rice straw, wheat straw and their mixture in equal proportion on a dry-matter (DM) basis. Four samples of each substrate were incubated aerobically in triplicate with P. ostreatus for 0 (Control), 21, 28 and 35 days under solid-state conditions (temperature, 24 ͦ C; humidity, 70± 5%). The changes in chemical composition, DM and nutrient losses, and rumen fermentation characteristics using in vitro DM digestibility (DMD) and the in vitro gas production (GP) technique were measured. The results showed that incubation with P. ostreatus decreased (P < 0.001) the contents of neutral detergent fibre and lignin with a concomitant increase (P < 0.001) in the contents of ash and crude protein. The losses of nutrients differed (P < 0.001) among the straw types, with rice straw and maize stover showing the largest (P < 0.05) lignin degradation compared to wheat and mixed straws. The DMD and 72-h cumulative GP increased (P < 0.001) consistently with increasing fungal incubation period and for all substrates the highest values of DMD and GP were measured after 35 days of incubation with P. ostreatus. The lignin degradation was strongly associated with hemicellulose degradation (r = 0.71) across the various straws. Results of the present study demonstrated that incubation of low-quality crop residues with P. ostreatus under solid-state conditions upgrades their feeding value by reducing the content of lignin and increasing the content of crude protein and ruminal degradation.

Keywords: crop residues, lignin degradation, maize stovers, wheat straws, white rot fungi

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Authors: Hossam Hegazi

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Global culture museums play a pivotal role in fostering cross-cultural connections, enhancing mutual understanding, and safeguarding the rich tapestry of cultural heritage. These institutions serve as dynamic bridges, facilitating the exchange of ideas and values among diverse societies. One of the primary functions of global culture museums is to connect people from different backgrounds. By showcasing the artistic expressions, traditions, and historical artifacts of various civilizations, these museums create a shared space for dialogue. Visitors are afforded the opportunity to explore and appreciate the nuances of cultures different from their own, promoting a sense of global interconnectedness. Moreover, these museums contribute significantly to mutual understanding. Through interactive exhibits, innovative technologies, and educational programs, they offer immersive experiences that transcend linguistic and geographical barriers. Visitors gain insights into the customs, beliefs, and lifestyles of others, fostering empathy and appreciation for cultural diversity. Preserving cultural heritage stands as another key objective of global culture museums. By housing and curating artifacts, artworks, and historical items, these institutions play a crucial role in safeguarding the collective memory of humanity. This preservation effort ensures that future generations have access to the cultural legacies that have shaped societies across the globe. In conclusion, global culture museums serve as dynamic hubs that bring people together, promote understanding, and safeguard the wealth of human cultural heritage. Their impact extends beyond the walls of exhibition halls, contributing to a more interconnected and culturally enriched world.

Keywords: global culture museums, cross-cultural connections, mutual understanding, societal dialogue

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Authors: Hedyeh Gamini, Hadi Abdus

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Tsunami, as a natural disaster, is composed of waves that are usually caused by severe movements at the sea floor. Although tsunami and its consequences cannot be prevented in any way, by examining past tsunamis and extracting key points on how to deal with this incident and learning from it, a positive step can be taken to reduce the vulnerability of human settlements and reduce the risk of this phenomenon in architecture and urbanism. The method is reviewing and has examined the documents written and valid internet sites related to managing and reducing the vulnerability of human settlements in face of tsunami. This paper has explored the tsunamis in Indonesia (2004), Sri Lanka (2004) and Japan (2011), and of the study objectives has been understanding how they dealt with tsunami and extracting key points, and the lessons from them in terms of reduction of vulnerability of human settlements in dealing with the tsunami. Finally, strategies to prevent and reduce the vulnerability of communities at risk of tsunamis have been offered in terms of architecture and urban planning. According to what is obtained from the study of the recent tsunamis, the authorities' quality of dealing with them, how to manage the crisis and the manner of their construction, it can be concluded that to reduce the vulnerability of human settlements against tsunami, there are generally four ways that are: 1-Construction of tall buildings with opening on the first floor so that water can flow easily under and the direction of the building should be in a way that water passes easily from the side. 2- The construction of multi-purpose centers, which could be used as vertical evacuation during accidents. 3- Constructing buildings in core forms with diagonal orientation of the coastline, 4- Building physical barriers (natural and synthetic) such as water dams, mounds of earth, sea walls and creating forests

Keywords: tsunami, architecture, reducing vulnerability, human settlements, urbanism

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Authors: Deria Adi Wijaya, Amad Saeroji, Jimmi Sandi P., Nanang Wijayanto

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Tourism and the creative economy are combinations that can become a sustainable source of welfare that can boost the economy so as to increase the country's foreign exchange. Therefore the development of the tourism sector is one of the priorities in President Joko Widodo's leadership framework for the 2019-2024 period. Entering the current pandemic, each party is required to be able to implement strict health protocols to slow the rate of SARS-Cov2 infection, or what is known as the coronavirus, but on the other hand, the need to turn the wheels of the economy must continue. Therefore, an effort is needed to develop tourism activities that are full of experiences that add health benefits. Anticipating this, the Ministry of Tourism and Creative Economy collaborated with the Ministry of Health to offer an innovative development model, namely wellness tourism. The development of wellness tourism is an alternative that can make a positive contribution to the development of Indonesian tourism during the pandemic. This research seeks to synergize efforts to develop national tourism into the regional sphere; in this case, Baluwarti Tourism Village, which is located within the walls of the Surakarta Sunanate Palace, has the potential to be developed into a wellness tourism destination in Surakarta City. Considering that a village that is in the immediate vicinity of a palace certainly has a variety of potential attractions for royal wellness tourism. The main objectives of this study are 1) to identify the potential for palace-style wellness tourism in Baluwarti Tourism Village; 2) to formulate development in the form of tour packages in Baluwarti Tourism Village. Of course, the development of the wellness tour package is still based on local wisdom, namely a tour package that raises local potential as a palace-style wellness tourism attraction that can improve the economy of the local people through the tourism sector in the post-pandemic era.

Keywords: potential, wellness tourism, Baluwarti Tourism Village, Surakarta Sunanate Palace, Surakarta City

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Authors: Marilia M. Camargo, Luisa A. Gachet-Barbosa, Rosa C. C. Lintz

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The addition of fibers into concrete matrix can enhance some properties of the composite, such as tensile, flexural and impact strengths, toughness, deformation capacity and post-cracking ductility. Many factors affect the mechanical behavior of fiber reinforced concrete, such as concrete matrix (concrete strength, additions, aggregate diameter, etc.), characteristics of the fiber (geometry, type, aspect ratio, volume, orientation, distribution, strength, stiffness, etc.), specimen (size, geometry, method of preparation and loading rate). This research investigates the effects of fiber volume and orientation on the post-cracking behavior of steel fiber reinforced concrete (SFRC). Hooked-end steel fibers with aspect ratios of 45 were added into concrete with volume of 0,32%, 0,64%, 0,94%. The post-cracking behaviour was assessed by double punch test of cubic specimens and the actual volume and orientation of the fibers were determined by non-destructive tests by means of electromagnetic induction. The results showed that the actual volume of fibers in each sample differs in a small amount from the dosed volume of fibers and that the deformation and toughness of the concrete increase with the increase in the actual volume of fibers. In determining the orientation of the fibers, it was found that they tend to distribute more in the X and Y axes due to the influence of the walls of the mold. In addition, it was concluded that the orientation of the fibers is important in the post-cracking behaviour of FRC when analyzed together with the actual volume of fibers, since the greater the volume of fibers, the greater the number of fibers oriented orthogonally to the application of loadings and, consequently, there is a better mechanical behavior of the composite. These results provide a better understanding of the influence of volume and fiber orientation on the post-cracking behavior of the FRC.

Keywords: fiber reinforced concrete, steel fibers, volume of fibers, orientation of fibers, post-cracking behaviour

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Authors: Akbar Khodavirdizadeh

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Gougerd village landslide with area about 150 hectares is located in southwest of Khoy city in northwest of the Iran. This Landslide was commenced more than 21 years and caused some damages in houses like some fissures on walls and some cracks on ground and foundations. The main mechanism of landslide is rotational with the high different of top and foot is about 230 m. The thickness of slide mass based on geoelectrical investigation is about 16m obtained. The upper layer of slope is silty sand and the lower layer of clayey gravel. In this paper, the stability of landslide are analyzed based in static analysis under different groundwater surface conditions and at slope angle changes with limit eqlibrium method and the simplified Bishop method. The results of the 72 stability analysis showed that the slope stability of Gougerd landslide increased with increasing of the groundwater surface depth of slope crown. And especially when decreased of slope angle, the safety facter more than in previous state is increased. The required of safety factor for stability in groundwater surface depth from slope crown equal 14 m and with decreased of slope angle to 3 degree at decrease of groundwater surface depth from slope crown equal 6.5 m obtained. The safety factor in critical conditions under groundwater surface depth from slope crown equal 3.5 m and at decreased of slope angle to 3 degree equal 0.5 m obtained. At groudwater surface depth from slope crown of 3 m, 7 m and 10 m respectively equal to 0.97, 1.19 and 1.33 obtained. At groudwater surface depth from slope crown of 3 m, 7 m and 10 m with decreased of slope angle to 3 degree, respectively equal to 1.27, 1.54 and 1.72 obtained. According to the results of this study, for 1 m of groundwater level decrease, the safety factor increased by 5%, and for 1 degree of reduction of the slope angle, safety factor increased by 15%. And the effect of slope angle on Gougerd landslide stability was felt more than groundwater effect.

Keywords: Gougerd landslide, stability analysis, slope angle, groundwater, Khoy

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Authors: Tan Dexian Arthur, James Wei Ming Kwek, Ian Loh, Lee Tee Sin

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Statement of the Problem: Mucoceles most commonly affect the frontal sinus, which results from chronic obstruction of the sinus ostium or cystic dilatation of mucous glands with ductal obstruction. They are known to cause bony erosion of the sinus walls, which can lead to large defects. These defects were typically managed by obliteration or cranialization of the frontal sinus. Although short term outcomes of conservative management of significant posterior table defects from fractures are promising, there have been no studies on the long-term outcomes of large dehiscences in the posterior wall of the frontal sinus. Methodology & Findings : Computed Tomography (CT) Paranasal Sinuses images were analyzed and found complete spontaneous osteogenesis of a large dehiscent frontal sinus posterior wall, secondary to a large mucocele, 9 years from functional endoscopic sinus surgery with the defect managed conservatively. Conclusion & Significance: The dura is well known for its osteogenic properties. Prior studies have showed that dura could induce osteogenesis in cutaneous tissue in the absence of other central nervous system structures. It was also demonstrated that osteogenesis and chondrogenesis were possible in zygomatic fractures by transplanting neonatal dura grafts to the bony defects in rats. Extrapolating from these studies, the authors postulate that the presence of dura beneath the bony deformity of the posterior frontal sinus wall had likely initiated the osteogenesis and restored the bony defect in the patient. In our literature review, we did not find any reports of spontaneous osteogenesis of large frontal sinus defects. While our experience is incidental, it reinforces the osteogenetic potential of an intact dura and further highlights that selected large defects of the posterior wall of the frontal sinus can be conservatively managed.

Keywords: paranasal sinus mucocele, mucocele, osteogenesis, dehiscence

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Authors: Junaid Asimiyu Mohammed, Olakunle Docas Tosin

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The housing environment in many developing countries is fraught with risks that have potential negative impacts on the lives of the residents. The study examined the risk factors in residential areas of two neighborhoods in Bosso Local Government Areas of Minna in Nigeria with a view to determining the level of their potential impacts. A sample of 378 households was drawn from the estimated population of 22,751 household heads. The questionnaire and direct observation were used as instruments for data collection. The data collected were analyzed using the Relative Importance Index (RII) rule to determine the level of the potential impact of the risk factors while ArcGIS was used for mapping the spatial distribution of the risks. The study established that the housing environment of Angwan Biri and El-Waziri areas of Bosso is poor and vulnerable as 26% of the houses were not habitable and 57% were only fairly habitable. The risks of epidemics, building collapse and rainstorms were evident in the area as 53% of the houses had poor ventilation; 20% of residents had no access to toilets; 47% practiced open waste dumping; 46% of the houses had cracked walls while 52% of the roofs were weak and sagging. The results of the analysis of the potential impact of the risk factors indicate a RII score of 0.528 for building collapse, 0.758 for rainstorms and 0.830 for epidemics, indicating a moderate to very high level of potential impacts. The mean RII score of 0.639 shows a significant potential impact of the risk factors. The study recommends the implementation of sanitation measures, provision of basic urban facilities and neighborhood revitalization through housing infrastructure retrofitting as measures to mitigate the risks of disasters and improve the living conditions of the residents of the study area.

Keywords: assessment, risk, residential, Nigeria

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Authors: Shyh-Ming Chern, Te-Hsiu Tang

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Hemicellulose is one of the major constituents of all plant cell walls, making up 15-25% of dry wood. It is a biopolymer from many different sugar monomers, including pentoses, like xylose, and hexoses, like mannose. In an effort to gasify real biomass in subcritical and supercritical water in a single process, it is necessary to understand the gasification of hemicellulose, in addition to cellulose and lignin, in subcritical and supercritical water. In the present study, xylose is chosen as the model compound for hemicellulose, since it has the largest amount in most hardwoods. Xylose is gasified in subcritical and supercritical water for the production of higher-valued gaseous products. Experiments were conducted with a 16-ml autoclave batch-type reactor. Hydrogen peroxide is adopted as the oxidant in an attempt to promote the gasification yield. The major operating parameters for the gasification include reaction temperature (400 - 600°C), reaction pressure (5 - 25 MPa), the concentration of xylose (0.05 and 0.30 M), and level of oxidant added (0 and 0.25 chemical oxygen demand). 102 experimental runs were completed out of 46 different set of experimental conditions. Product gases were analyzed with a GC-TCD and determined to be mainly composed of H₂ (10 – 74 mol. %), CO (1 – 56 mol. %), CH₄ (1 – 27 mol. %), CO₂ (10 – 50 mol. %), and C₂H₆ (0 – 8 mol. %). It has been found that the gas yield (amount of gas produced per gram of xylose gasified), higher heating value (HHV) of the dry product gas, and energy yield (energy stored in the product gas divided by the energy stored in xylose) all increase significantly with rising temperature and moderately with reducing pressure. The overall best operating condition occurred at 873 K and 10 MPa, with a gas yield of 54 mmol/g of xylose, a gas HHV of 440 kJ/mol, and an energy yield of 1.3. A seemingly unreasonably energy yield of greater than unity resulted from the external heating employed in the experiments to drive the gasification process. It is concluded that xylose can be completely gasified in subcritical and supercritical water under proper operating conditions. The addition of oxidant does not promote the gasification of xylose.

Keywords: gasification, subcritical water, supercritical water, xylose

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Authors: Berna Istegun, Erkan Celebi

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The main objective of this experimental study is to assess the shear strength and the crack behavior of the triplets built of perforated brickwork masonry elements. In order to observe the influence of shear resistance and energy dissipating before and after retrofitting applications by using the reinforcing system, static-cyclic shear tests were employed in the structural mechanics laboratory of Sakarya University. The reinforcing system is composed of hybrid multiaxial seismic fabric consisting of alkali resistant glass and polypropylene fibers. The plaster as bonding material used in the specimen’s retrofitting consists of expanded glass granular. In order to acquire exact measuring data about the failure behavior of the two mortar joints under shear stressing, vertical load-controlled cylinder having force capacity of 50 kN and loading rate of 1.5 mm/min. with an internal inductive displacement transducers is carried out perpendicular to the triplet specimens. In this study, a total of six triplet specimens with textile reinforcement were prepared for these shear bond tests. The three of them were produced as single-sided reinforced triplets with seismic fabric, while the others were strengthened on both sides. In addition, three triplet specimens without retrofitting and plaster were also tested as reference samples. The obtained test results were given in the manner of force-displacement relationships, ductility coefficients and shear strength parameters comparatively. It is concluded that two-side seismic textile applications on masonry elements with relevant plaster have considerably increased the sheer force resistance and the ductility capacity.

Keywords: expanded glass granular, perforated brickwork, retrofitting, seismic fabric, triplet shear tests

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Authors: Iqra Raza

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This paper attempts to conceptualize the (de)humanization of the Muslim subject in Karen J. Greenberg and Janet Hamlin’s transmedia Sketching Guantanamo through a close study of the aesthetics and semiotics of the text. The Muslim experience, the paper shall argue, is mediated through a (de)humanization confined and incarcerated within the chains of artistic representation. Hamlin’s reliance on the distortions offered by stereotypes is reminiscent of the late Victorian epistemology on criminality, as evidenced most starkly in the sketch of Khalid Sheikh Mohammad. The position of the white artist thus becomes suspect in the enterprise of neo-Victorian ethnography. The visual stories of movement from within Guantanamo become potent; the paper shall argue, especially in juxtaposition with the images of stillness that came out from the detention centers, which portrayed the enactment of violence on individual bodies with a deliberate erasure of faces. So, while art becomes a way for reclaiming subjectivity or humanizing these identifiable bodies, the medium predicates itself on their objectification. The paper shall explore various questions about what it means for the (criminal?) subjects to be rendered into art rather than being photographed. Does art entail a necessary departure from the assumed objectivity of the photographic images? What makes art the preferred medium for (de)humanization of the violated Muslim bodies? What happens when art is produced without a recognition of the ‘precariousness’ of the life being portrayed? Rendering the detainees into art becomes a slippery task complicated by Hamlin’s privileged position outside the glass walls of the court. The paper shall adjourn analysis at the many dichotomies that exist in the text viz. between the White men and the brown, the Muslims and the Christians, Occident and the Orient problematized by Hamlin’s politics, that of a ‘neutral outsider’ which quickly turns on its head and becomes complicity in her deliberate erasure of the violence that shaped and still shapes Guantanamo.

Keywords: Abu Ghraib, Derrida, Guantanamo, graphic journalism, Muslimness, orient, spectrality

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Authors: Amany Haridy, Ahmed Elseragy, Fahd Omar

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The issue of temperature increase in the urban microclimate has been at the center of attention recently, especially in dense urban areas, such as the City of Alexandria in Egypt, where building surfaces have become the dominant element (more than green areas and streets). Temperatures have been rising during daytime as well as nighttime, however, the research focused on the rise of air temperature at night, a phenomenon known as the urban heat island. This phenomenon has many effects on ecological life, as well as human health. This study provided evidence of the possibility of reducing the urban heat island by using a green building envelope (green wall and green roof) in Alexandria, Egypt. This City has witnessed a boom in growth in its urban fabric and population. A simulation analysis using the Envi-met software to find the ratio of air temperature reduction was performed. The simulation depended on the orientation of the green areas and their density, which was defined through a process of climatic analysis made by the Diva plugin using the Grasshopper software. Results showed that the reduction in air temperature varies from 0.8–2.0 °C, increasing with the increasing density of green areas. Many systems of green wall and green roof can be found in the local market. However, treating an existing building requires a careful choice of system to fit the building construction load and the surrounding nature. Among the systems of choice, there was the ‘geometric system’ of vertical greening that can be fixed on a light aluminum structure for walls and the extensive green system for roofs. Finally, native plants were the best choice in the long term because they fare well in the local climate.

Keywords: envi-met, green building envelope, urban heat island, urban microclimate

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Authors: Anna Yagodnitsyna, Alexander Kovalev, Artur Bilsky

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The efficiency of certain technological processes in two-phase microfluidics such as emulsion production, nanomaterial synthesis, nitration, extraction processes etc. depends on two-phase flow regimes in microchannels. For practical application in chemistry and biochemistry it is very important to predict the expected flow pattern for a large variety of fluids and channel geometries. In the case of immiscible liquids, the plug flow is a typical and optimal regime for chemical reactions and needs to be predicted by empirical data or correlations. In this work flow patterns of immiscible liquid-liquid flow in a rectangular microchannel with T-junction are investigated. Three liquid-liquid flow systems are considered, viz. kerosene – water, paraffin oil – water and castor oil – paraffin oil. Different flow patterns such as parallel flow, slug flow, plug flow, dispersed (droplet) flow, and rivulet flow are observed for different velocity ratios. New flow pattern of the parallel flow with steady wavy interface (serpentine flow) has been found. It is shown that flow pattern maps based on Weber numbers for different liquid-liquid systems do not match well. Weber number multiplied by Ohnesorge number is proposed as a parameter to generalize flow maps. Flow maps based on this parameter are superposed well for all liquid-liquid systems of this work and other experiments. Plug length and velocity are measured for the plug flow regime. When dispersed liquid wets channel walls plug length cannot be predicted by known empirical correlations. By means of particle tracking velocimetry technique instantaneous velocity fields in a plug flow regime were measured. Flow circulation inside plug was calculated using velocity data that can be useful for mass flux prediction in chemical reactions.

Keywords: flow patterns, hydrodynamics, liquid-liquid flow, microchannel

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Authors: Nan Xu

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In airlines, the crew scheduling problem is usually decomposed into two stages: crew pairing and crew rostering. In the crew pairing stage, pairings are generated such that each flight is covered by exactly one pairing and the overall cost is minimized. In the crew rostering stage, the pairings generated in the crew pairing stage are combined with off days, training and other breaks to create individual work schedules. The paper focuses on cabin crew rostering problem, which is challenging due to the extremely large size and the complex working rules involved. In our approach, the objective of rostering consists of two major components. The first is to minimize the number of unassigned pairings and the second is to ensure the fairness to crew members. There are two measures of fairness to crew members, the number of overnight duties and the total fly-hour over a given period. Pairings should be assigned to each crew member so that their actual overnight duties and fly hours are as close to the expected average as possible. Deviations from the expected average are penalized in the objective function. Since several small deviations are preferred than a large deviation, the penalization is quadratic. Our model of the airline crew rostering problem is based on column generation. The problem is decomposed into a master problem and subproblems. The mater problem is modeled as a set partition problem and exactly one roster for each crew is picked up such that the pairings are covered. The restricted linear master problem (RLMP) is considered. The current subproblem tries to find columns with negative reduced costs and add them to the RLMP for the next iteration. When no column with negative reduced cost can be found or a stop criteria is met, the procedure ends. The subproblem is to generate feasible crew rosters for each crew member. A separate acyclic weighted graph is constructed for each crew member and the subproblem is modeled as resource constrained shortest path problems in the graph. Labeling algorithm is used to solve it. Since the penalization is quadratic, a method to deal with non-additive shortest path problem using labeling algorithm is proposed and corresponding domination condition is defined. The major contribution of our model is: 1) We propose a method to deal with non-additive shortest path problem; 2) Operation to allow relaxing some soft rules is allowed in our algorithm, which can improve the coverage rate; 3) Multi-thread techniques are used to improve the efficiency of the algorithm when generating Line-of-Work for crew members. Here a column generation based algorithm for the airline cabin crew rostering problem is proposed. The objective is to assign a personalized roster to crew member which minimize the number of unassigned pairings and ensure the fairness to crew members. The algorithm we propose in this paper has been put into production in a major airline in China and numerical experiments show that it has a good performance.

Keywords: aircrew rostering, aircrew scheduling, column generation, SPPRC

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Authors: Maryam Pirdehghan

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During the Ba'ath Party's rule in Iraq, propaganda was utilized to justify and to promote Saddam Hussein's image in the collective memory as the greatest Arab leader. Consequently, urban walls were routinely covered with images of Saddam. Relying on these images, the regime aimed to provide a basis for evoking meanings in the public opinion, which would supposedly strengthen Saddam’s power and reconstruct facts to legitimize his political ideology. Nonetheless, Saddam was not always portrayed with common and explicit elements but in certain periods of his rule, the paintings depicted him in an unusual context, where various historical and contemporary elements were combined in a narrative background. Therefore, an understanding of the implied socio-political references of these elements is required to fully elucidate the impact of these images on forming the memory and collective unconscious of the Iraqi people. To obtain such understanding, one needs to address the following questions: a) How Saddam Hussein is portrayed in mural during his rule? b) What of elements and mythical-historical narratives are found in the paintings? c) Which Saddam's political views were subject to the collective memory through mural? Employing visual semiotics, this study reveals that during Saddam Hussein's regime, the paintings were initially simple portraits but gradually transformed into narrative images, characterized by a complex network of historical, mythical and religious elements. These elements demonstrate the transformation of a secular-nationalist politician into a Muslim ruler who tried to instill three major policies in domestic and international relations i.e. the arabization of Iraq, as well as the propagation of pan-arabism ideology (first period), the implementation of anti-Israel policy (second period) and the implementation of anti-American-British policy (last period).

Keywords: Ba'ath Party, Saddam Hussein, mural, Iraq, propaganda, collective memory

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Authors: Sweta Agrawal, Sachin Chaugule, Gargi Rane, Shashank More, Madhavi Indap

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Angiogenesis and metastasis are two of the most important hallmarks of cancer. Hence, most of the cancer therapies nowadays are multi-targeted so as to reduce resistance and have better efficacy. As synthetic molecules arise with a burden of their toxicities and side-effects, more and more research is being focussed on exploiting the vast natural resources of drugs, in the form of plants and animals. Although, the idea of using marine organisms as a source of pharmaceuticals is not new, the pace at which marine drugs are being discovered, has definitely up surged! In the present study, we have assessed the anti-angiogenic and in vitro anti-metastatic activity of aqueous fraction from the extract of marine gastropod Euchelus asper. The soft body of Euchelus Asper was extracted with methanol and named EAME. Partition chromatography of EAME gave three fractions EAME I, II and III. Biochemical analysis revealed the presence of proteins in EAME III. Preliminary analysis had revealed the anti-angiogenic activity was exhibited by EAME III out of the three fractions. Hereafter, EAME III (concentration 25µg/ml-400µg/ml) was tested on chick chorioallantoic membrane (CAM) model for the detailed analysis of its potential anti-angiogenic effect. In vitro testing of the fraction (concentration 0.25µg/ml - 1µg/ml), involved cytotoxicity by SRB assay, cell cycle analysis by flow cytometry and anti-proliferative effect by scratch wound healing assay on A549 lung carcinoma cells. Apart from this, a portion of treated CAM as well as conditioned medium from treated A549 were subjected to gelatin zymography for assessment of matrix metalloproteinases MMP-2 and MMP-9 levels. Our results revealed that EAME III exhibited significant anti-angiogenic activity on CAM which was also supported by histological observations. During histological studies of CAM, it was found that EAME III caused reduction in angiogenesis by altering the extracellular matrix of the CAM membrane. In vitro analysis disclosed that EAME III exhibited moderate cytotoxic effect on A549 cells and its effect was not dose-dependent. The results of flow cytometry confirmed that EAME III caused cell cycle arrest in A549 cell line as almost all of the treated cells were found in G1 phase. Further, the migration and proliferation of A549 was significantly reduced by EAME III as observed from the scratch wound assay. Moreover, Gelatin zymography analysis revealed that EAME III caused suppression of MMP-2 in CAM membrane and reduced MMP-9 and MMP-2 expression in A549 cells. This verified that the anti-angiogenic and anti-metastatic effects of EAME III were correlated with the suppression of MMP-2 and -9. To conclude, EAME III shows dual anti-tumour action by reducing angiogenesis and exerting anti-metastatic effect on lung cancer cells, thus it has the potential to be used as an anti-cancer agent against lung carcinoma.

Keywords: angiogenesis, anti-cancer, marine drugs, matrix metalloproteinases

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Authors: Camila Parodi, Viviana Letelier, Giacomo Moriconi

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The cement industry is responsible for around a 5% of the CO2 emissions worldwide and considering that concrete is one of the most used materials in construction its total effect is important. An alternative to reduce the environmental impact of concrete production is to incorporate certain amount of residues in the dosing, limiting the replacement percentages to avoid significant losses in the mechanical properties of the final material. Previous researches demonstrate the feasibility of using brick and rust residues, separately, as a cement replacement. This study analyses the variation in the mechanical properties of mortars by incorporating masonry residue composed of clay bricks and cement mortar. In order to improve the mechanical properties of masonry residue, this was subjected to a heat treatment of 650 ° C for four hours and its effect is analyzed in this study. Masonry residue was obtained from a demolition of masonry perimetral walls. The residues were crushed and sieved and the maximum size of particles used was 75 microns. The percentages of cement replaced by masonry residue were 0%, 10%, 20% and 30%. The effect of masonry residue addition and its heat treatment in the mechanical properties of mortars is evaluated through compressive and flexural strength tests after 7, 14 and 28 curing days. Results show that increasing the amount of masonry residue used increases the losses in compressive strength and flexural strength. However, the use of up to a 20% of masonry residue, when a heat treatment is applied, allows obtaining mortars with similar compressive strength to the control mortar. Masonry residues mortars without a heat treatment show losses in compressive strengths between 15% and 27% with respect to masonry residues with heat treatment, which demonstrates the effectiveness of the heat treatment. From this analysis it can be conclude that it is possible to use up to 20% of masonry residue with heat treatment as cement replacement without significant losses in mortars mechanical properties, reducing considerably the environmental impact of the final material.

Keywords: cement replacement, environmental impact, masonry residue, mechanical properties of recycled mortars

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Authors: Jerzy Smardzewski

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Structures with negative Poisson's ratios are called auxetic. They are characterized by better mechanical properties than conventional structures, especially shear strength, the ability to better absorb energy and increase strength during bending, especially in sandwich panels. Commonly used paper cores of cellular boards are made of hexagonal cells. With isotropic facings, these cells provide isotropic properties of the entire furniture board. Shelves made of such panels with a thickness similar to standard chipboards do not provide adequate stiffness and strength of the furniture. However, it is possible to transform the shape of hexagonal cells into polyhedral auxetic cells that improve the mechanical properties of the core. The work aimed to transform the hexagonal cells of the paper core into auxetic cells and determine their basic mechanical properties. Using numerical methods, it was decided to design the most favorable proportions of cells distinguished by the lowest Poisson's ratio and the highest modulus of linear elasticity. Standard cores for cellular boards commonly used to produce 34 mm thick furniture boards were used for the tests. Poisson's ratios, bending strength, and linear elasticity moduli were determined for such cores and boards. Then, the cells were transformed into auxetic structures, and analogous cellular boards were made for which mechanical properties were determined. The results of numerical simulations for which the variable parameters were the dimensions of the cell walls, wall inclination angles, and relative cell density were presented in the further part of the paper. Experimental tests and numerical simulations showed the beneficial effect of auxeticization on the mechanical quality of furniture panels. They allowed for the selection of the optimal shape of auxetic core cells.

Keywords: auxetics, honeycomb, panels, simulation, experiment

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Authors: Rony Reátegui, Cesar Chácara, Benjamin Castañeda, Rafael Aguilar

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Nowadays, heritage building information modeling (HBIM) is considered an efficient tool to represent and manage information of cultural heritage (CH). The basis of this tool relies on a 3D model generally obtained from a cloud-to-BIM procedure. There are different methods to create an HBIM model that goes from manual modeling based on the point cloud to the automatic detection of shapes and the creation of objects. The selection of these methods depends on the desired level of development (LOD), level of information (LOI), grade of generation (GOG), as well as on the availability of commercial software. This paper presents the 3D modeling of a stone masonry chapel using Recap Pro, Revit, and Dynamo interface following a three-step methodology. The first step consists of the manual modeling of simple structural (e.g., regular walls, columns, floors, wall openings, etc.) and architectural (e.g., cornices, moldings, and other minor details) elements using the point cloud as reference. Then, Dynamo is used for generative modeling of complex structural elements such as vaults, infills, and domes. Finally, semantic information (e.g., materials, typology, state of conservation, etc.) and pathologies are added within the HBIM model as text parameters and generic models families, respectively. The application of this methodology allows the documentation of CH following a relatively simple to apply process that ensures adequate LOD, LOI, and GOG levels. In addition, the easy implementation of the method as well as the fact of using only one BIM software with its respective plugin for the scan-to-BIM modeling process means that this methodology can be adopted by a larger number of users with intermediate knowledge and limited resources since the BIM software used has a free student license.

Keywords: cloud-to-BIM, cultural heritage, generative modeling, HBIM, parametric modeling, Revit

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Authors: Paulinus W. Ihuah, Iyenemi Ibimina Kakulu, Victor A. Akujuru

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The development of the residential property is very expensive in Nigeria, especially as it is observed in Port Harcourt, although it is also investment costly in the other cities of Nigeria. The costly development nature incidentally reasons to the high deficits in residential property availability and affordability for the low-income people. Therefore, the main purpose of this paper is to provide sustainable accommodation design, which should improve residential property expensiveness and shortages for the low-income people. This is achieved through investigation of the tangible requirements and needs of the end-user of the property (low-income people), which thereafter would enhance sustainable and affordable residential property accommodation design for the end-users. Both the quantitative and qualitative instruments of data collection were utilised. The quantitative instrument via questionnaires was designed to examine the real needs and r requirement of the low-income people. However, the qualitative instrument via structured interview was espoused for the gathering of professionals’ opinions on the three predicted sustainable accommodation design alternatives. The analysis employed content analysis parameters, which offered a sustainable accommodation design and designed alternatives minimises costs and environmental impacts whereas exploiting the social satisfaction in residential accommodation developments. The finding underscores that sustainable accommodation design and development is practicable in Nigeria, so that cost of residential accommodation provided through this system is cheap to the low-income people. Further, erection of multi-storey residential accommodation units such as bedsit structure by utilising the concrete frame structure and building the internal and external walls with hollow concrete blocks within areas 60-130 square meters is encouraged. This paper philosophy indicates that by using sustainable accommodation design practices in Nigeria, improvements in the costs and shortages of residential accommodation can be attained for low-income people. However, policies support the government cannot be overemphasised for proper implementation of the suggested scheme.

Keywords: sustainable accommodation, housing design, residential property, low-income people

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Authors: Sherman Ho, Ahmed Cherif Megri

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Headers play a critical role in conveying steam to regulate heating system temperatures. While various materials like steel grades 91 and 92 have been traditionally used for pipes, this research proposes the use of a robust and innovative material, INCONEL Alloy 740H. Boilers in power plant configurations are exposed to cycling conditions due to factors such as daily, seasonal, and yearly variations in weather. These cycling conditions can lead to the deterioration of headers, which are vital components with intricate geometries. Header failures result in substantial financial losses from repair costs and power plant shutdowns, along with significant public inconveniences such as the loss of heating and hot water. To address this issue and seek solutions, a mechanical analysis, as well as a structural analysis, are recommended. Transient analysis to predict heat transfer conditions is of paramount importance, as the direction of heat transfer within the header walls and the passing steam can vary based on the location of interest, load, and operating conditions. The geometry and material of the header are also crucial design factors, and the choice of pipe material depends on its usage. In this context, the heat transfer coefficient plays a vital role in header design and analysis. This research employs ANSYS Fluent, a numerical simulation program, to understand header behavior, predict heat transfer, and analyze mechanical phenomena within the header. Transient simulations are conducted to investigate parameters like heat transfer coefficient, pressure loss coefficients, and heat flux, with the results used to optimize header design.

Keywords: CFD, header, power plant, heat transfer coefficient, simulation using experimental data

Procedia PDF Downloads 66

Authors: Mustapha A. Tijjani, Fanna I. Abdulrahman, Irfan Z. Khan, Umar K. Sandabe, Cong Li

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Air dried sample V. doniana after collection and identification was extracted with ethanol and further partition with chloroform, ethyl acetate and n-butanol. Ethanolic extract (11.9g) was fractionated on a silica gel accelerated column chromatography using solvents such as n-hexane, ethyl acetate and methanol. Each eluent fractions (150ml aliquots) were collected and monitored with thin layer chromatography. Fractions with similar Rf values from same solvents system were pooled together. Phytochemical test of all the fractions were performed using standard procedure. Complete elution yielded 48 fractions (150ml/fraction) which were pooled to 24 fractions base on the Rf values. It was further recombined and 12 fractions were obtained on the basis on Rf values and coded Vd1 to Vd12 fractions. Vd8 was further eluted with ethylacetate and methanol and gave fourteen sub fractions Vd8-a, -Vd8-m. Fraction Vd8-a (56mg) gave a white crystal compound coded V1. It was further checked on TLC and observed under ultraviolet lamp and was found to give a single spot. The Rf values were calculated to be 0.433. The melting point was determined using Gallenkamp capillary melting point apparatus and found to be 241-243°C uncorrected. Characterization of the isolated compound coded V1 was done using FT-infra-red spectroscopy, HNMR, 13CNMR(1and 2D) and HRESI-MS. The IR spectrum of compound V1 shows prominent peaks that corresponds to OHstr (3365cm-1) and C=0 (1652cm-1) etc. This spectrum suggests that among the functional moiety in compound V1 are the carbonyl and hydroxyl group. The 1H NMR (400 MHz) spectrum of compound V1 in DMSO-d6 displayed five singlet signals at δ 0.72 (3H, s, H-18), 0.79 (3H, s, H-19), 1.03 (3H, s, H-21), 1.04 (3H, s, H-26), 1.06 (3H, s, H-27) each integrating for three protons indicating the five methyl functional groups present in the compound. It further showed a broad singlet at δ 5.58 integrated for 1 H due to an olefinic H-atom adjacent to the carbonyl carbon atom. Three signals at δ 3.10 (d, J = 9.0 Hz, H-22), 3.59 (m, 1H, 2H-a) and 3.72 (m, 1H, 3H-e), each integrating for one proton is due to oxymethine protons indicating that three oxymethine H-atoms are present in the compound. These all signals are characteristic to the ecdysteroid skeletons. The 13C-NMR spectrum showed the presence of 27 carbon atoms, suggesting that may be steroid skeleton. The DEPT-135 experiment showed the presence of five CH3, eight CH2, and seven CH groups, and seven quaternary C-atoms. The molecular formula was established as C27H44O7 by high resolution electron spray ionization-mass spectroscopy (HRESI-MS) positive ion mode m/z 481.3179. The signals in mass spectrum are 463, 445, and 427 peaks corresponding to losses of one, two, three, or four water molecules characteristic for ecdysterone skeleton reported in the literature. Based on the spectral analysis (HNMR, 13CNMR, DEPT, HMQC, IR, HRESI-MS) the compound V1 is thus concluded to have ecdysteriod skeleton and conclusively conforms with 2β, 3β 14α, 20R, 22R, 25-hexahydroxy-5 β cholest-7-ene-6- one, or 2, 3, 14, 20, 22, 25 hexahydroxy cholest-7-ene-6-one commonly known as 20-hydroxyecdysone.

Keywords: vitex, phytochemical, purification, isolation, chromatography, spectroscopy

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Authors: Rene Jimenez, Sonia E. Ruiz, Miguel A. Orellana

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On 09/19/2017, a Mw = 7.1 intraslab earthquake occurred in Mexico causing the collapse of about 40 buildings. Many of these were 5- or 6-story buildings with soft first story; so, it is desirable to perform a structural fragility analysis of typical structures representative of those buildings and to propose a reliable structural solution. Here, a typical 5-story building constituted by regular R/C moment-resisting frames in the first story and confined masonry walls in the upper levels, similar to the collapsed structures on the 09/19/2017 Mexico earthquake, is analyzed. Three different structural solutions of the 5-story building are considered: S1) it is designed in accordance with the Mexico City Building Code-2004; S2) then, the column dimensions of the first story corresponding to S1 are reduced, and S3) viscous dampers are added at the first story of solution S2. A number of dynamic incremental analyses are performed for each structural solution, using a 3D structural model. The hysteretic behavior model of the masonry was calibrated with experiments performed at the Laboratory of Structures at UNAM. Ten seismic ground motions are used to excite the structures; they correspond to ground motions recorded in intermediate soil of Mexico City with a dominant period around 1s, where the structures are located. The fragility curves of the buildings are obtained for different values of the maximum inter-story drift demands. Results show that solutions S1 and S3 give place to similar probabilities of exceedance of a given value of inter-story drift for the same seismic intensity, and that solution S2 presents a higher probability of exceedance for the same seismic intensity and inter-story drift demand. Therefore, it is concluded that solution S3 (which corresponds to the building with soft first story and energy dissipation devices) can be a reliable solution from the structural point of view.

Keywords: demand hazard analysis, fragility curves, incremental dynamic analyzes, soft-first story, structural capacity

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Authors: Syed Ameer Haider Jafri

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The primary goal of a root canal treatment in deciduous teeth is to eliminate infection and to retain the tooth in a functional state until it gets physiologically exfoliated and replaced by permanent successor. Important requisite of a root canal filling material for primary teeth is that, it should resorb at a similar rate as the roots of primary tooth, be harmless to the periapical tissue and to the permanent tooth germ, resorb readily if pushed beyond the apex, be antiseptic, radio-opaque, should not shrink, adhere to the walls, not discolor the tooth and easy to fill & remove, if required at any stage. Presently available, commonly used obturating materials for primary teeth are zinc oxide eugenol, calcium hydroxide and iodoform based pastes. None of these materials so far meet the ideal requirement of root canal filling material. So in search of ideal obturating material, this study was planed, in which mixture of calcium hydroxide, zinc oxide & sodium fluoride and mixture of calcium hydroxide & sodium fluoride was compared clinically and radiographically with calcium hydroxide for the obturation of root canals of 75 carious exposed primary mandibular second molars of 59 children aged 4-9 years. All the three material shows good results, but after a follow-up of 9 months mixture of calcium hydroxide, two percent sodium fluoride & zinc oxide powder closely follow the resorption of root, mixture of calcium hydroxide, two percent sodium fluoride follow resorption of root in the beginning but later on majority of cases shows faster resorption whereas calcium hydroxide starts depleting from the canal from the beginning even as early as 3 months. Thus mixture of calcium hydroxide, two percent sodium fluoride & zinc oxide found to be best obturaring material for primary tooth.

Keywords: obturating material, primary teeth, root canal treatment, success rate

Procedia PDF Downloads 305

Authors: David L. Olson, Stephen B. H. Bruder, Adam S. Watkins, Cleon E. Davis

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In global navigation satellite systems (GNSS), denied settings such as indoor environments, autonomous mobile robots are often limited to dead-reckoning navigation techniques to determine their position, velocity, and attitude (PVA). Localization is typically accomplished by employing an inertial measurement unit (IMU), which, while precise in nature, accumulates errors rapidly and severely degrades the localization solution. Standard sensor fusion methods, such as Kalman filtering, aim to fuse precise IMU measurements with accurate aiding sensors to establish a precise and accurate solution. In indoor environments, where GNSS and no other a priori information is known about the environment, effective sensor fusion is difficult to achieve, as accurate aiding sensor choices are sparse. However, an opportunity arises by employing a depth camera in the indoor environment. A depth camera can capture point clouds of the surrounding floors and walls. Extracting attitude from these surfaces can serve as an accurate aiding source, which directly combats errors that arise due to gyroscope imperfections. This configuration for sensor fusion leads to a dramatic reduction of PVA error compared to traditional aiding sensor configurations. This paper provides the theoretical basis for the depth camera aiding sensor method, initial expectations of performance benefit via simulation, and hardware implementation, thus verifying its veracity. Hardware implementation is performed on the Quanser Qbot 2™ mobile robot, with a Vector-Nav VN-200™ IMU and Kinect™ camera from Microsoft.

Keywords: autonomous mobile robotics, dead reckoning, depth camera, inertial navigation, Kalman filtering, localization, sensor fusion

Procedia PDF Downloads 207

Authors: Ruthanne Tobin

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The shift to a personalized learning (PL) curriculum in Canada represents an innovative approach to teaching and learning that is also evident in various initiatives across the 32-nation OECD. The premise behind PL is that empowering individual learners to have more input into how they access and construct knowledge, and express their understanding of it, will result in more meaningful school experiences and academic success. In this paper presentation, the author reports on a document analysis of the new curriculum in the province of British Columbia. Three theoretical frameworks are used to analyze the new curriculum. Framework 1 focuses on five dominant aspects (FDA) of PL at the classroom level. Framework 2 focuses on conceptualizing and enacting personalized learning (CEPL) within three spheres of influence. Framework 3 focuses on the integration of three types of knowledge (content, technological, and pedagogical). Analysis is ongoing, but preliminary findings suggest that the new curriculum addresses framework 1 quite well, which identifies five areas of personalized learning: 1) assessment for learning; 2) effective teaching and learning; 3) curriculum entitlement (choice); 4) school organization; and 5) “beyond the classroom walls” (learning in the community). Framework 2 appears to be less well developed in the new curriculum. This framework speaks to the dynamics of PL within three spheres of interaction: 1) nested agency, comprised of overarching constraints [and enablers] from policy makers, school administrators and community; 2) relational agency, which refers to a capacity for professionals to develop a network of expertise to serve shared goals; and 3) students’ personalized learning experience, which integrates differentiation with self-regulation strategies. Framework 3 appears to be well executed in the new PL curriculum, as it employs the theoretical model of technological, pedagogical content knowledge (TPACK) in which there are three interdependent bodies of knowledge. Notable within this framework is the emphasis on the pairing of technologies with excellent pedagogies to significantly assist students and teachers. This work will be of high relevance to educators interested in innovative school reform.

Keywords: curriculum reform, K-12 school change, innovations in education, personalized learning

Procedia PDF Downloads 282

Authors: Palak J. Shukla, Atul K. Desai, Chentankumar D. Modhera

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For any country in the world, it has become a priority to protect the critical infrastructure from looming risks of terrorism. In any infrastructure system, the structural elements like lower floors, exterior columns, walls etc. are key elements which are the most susceptible to damage due to blast load. The present study revisits the state of art review of the design and analysis of reinforced concrete panels subjected to blast loading. Various aspects in association with blast loading on structure, i.e. estimation of blast load, experimental works carried out previously, the numerical simulation tools, various material models, etc. are considered for exploring the current practices adopted worldwide. Discussion on various parametric studies to investigate the effect of reinforcement ratios, thickness of slab, different charge weight and standoff distance is also made. It was observed that for the simulation of blast load, CONWEP blast function or equivalent numerical equations were successfully employed by many researchers. The study of literature indicates that the researches were carried out using experimental works and numerical simulation using well known generalized finite element methods, i.e. LS-DYNA, ABAQUS, AUTODYN. Many researchers recommended to use concrete damage model to represent concrete and plastic kinematic material model to represent steel under action of blast loads for most of the numerical simulations. Most of the studies reveal that the increase reinforcement ratio, thickness of slab, standoff distance was resulted in better blast resistance performance of reinforced concrete panel. The study summarizes the various research results and appends the present state of knowledge for the structures exposed to blast loading.

Keywords: blast phenomenon, experimental methods, material models, numerical methods

Procedia PDF Downloads 157

Authors: R. Adwaith, J. Gopinath, Vasantha Kohila B., R. Chandru, Arul Prakash R.

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The turbofan engine is a type of air breathing engine that is widely used in aircraft propulsion produces thrust mainly from the mass-flow of air bypassing the engine core. The present research has developed an effective method numerically by increasing the thrust generated from the bypass air. This thrust increase is brought about by heating the walls of the bypass valve from the combustion chamber using convective heat transfer method. It is achieved computationally by the use external heat to enhance the velocity of bypass air of turbofan engines. The bypass valves are either heated externally using multicell tube resistor which convert electricity generated by dynamos into heat or heat is transferred from the combustion chamber. This increases the temperature of the flow in the valves and thereby increase the velocity of the flow that enters the nozzle of the engine. As a result, mass-flow of air passing the core engine for producing more thrust can be significantly reduced thereby saving considerable amount of Jet fuel. Numerical analysis has been carried out on a scaled down version of a typical turbofan bypass valve, where the valve wall temperature has been increased to 700 Kelvin. It is observed from the analysis that, the exit velocity contributing to thrust has significantly increased by 10 % due to the heating of by-pass valve. The degree of optimum increase in the temperature, and the corresponding effect in the increase of jet velocity is calculated to determine the operating temperature range for efficient increase in velocity. The technique used in the research increases the thrust by using heated by-pass air without extracting much work from the fuel and thus improve the efficiency of existing turbofan engines. Dimensional analysis has been carried to prove the accuracy of the results obtained numerically.

Keywords: turbofan engine, bypass valve, multi-cell tube, convective heat transfer, thrust

Procedia PDF Downloads 358