The influence of an applied magnetic field on the collective dynamics of novel anisotropic colloidal particles whose shape resembles peanuts is reported. Being made up of hematite cores and silica shells, these micrometer-sized particles align in a direction perpendicular to the applied external magnetic field, and assemble into chains along the field direction. The anisotropic dynamics of these particles is investigated using multispeckle ultrasmall-angle X-ray photon correlation spectroscopy (USA-XPCS). The results indicate that along the direction of the magnetic field, the particle dynamics strongly depends on the length scale probed. Here, the relaxation of the intermediate scattering function follows a compressed exponential behavior at large distances, while it appears diffusive at distances comparable or smaller than the particle size. Perpendicular to the applied field (and along the direction of gravity), the experimental data can be quantitatively reproduced by a combination of an advective term originating from sedimentation and a purely diffusive one that describes the thermal diffusion of the assembled chains and individual particles.
With the rapid development and modernisation, cities are growing at a very fast pace and the buildings are the main component of cities. Building construction in the world annually consumes around 25% of the global wood harvest, 40% of stone, sand and gravel and 16% of water. It generates 50% of global output of GHG and agents of acid rains. The manufacturing process of building material contributes to Green House Gases such as CO2 to the atmosphere to a great extent. The natural disasters like global warming, ozone layer depletion, unexpected seasonal variations and decreasing land surface have now moved the centre of attraction from development to sustainable development. Since we have limited resources and energy, our development should focus on conserving the energy. Due to the continuous exploitation of natural resources, there is an urge to produce environmentally responsive building material for the construction of new buildings to meet the rapid urban growth. Sustainable buildings are designed, constructed, maintained, rehabilitated, and demolished with an emphasis throughout their life cycle on using natural resources efficiently while also protecting global ecosystems. Selection of appropriate building material helps to use the energy efficiently. In the rapidly changing scenario of building sector, planners, architects, engineers and builders are looking for new materials and technologies to adopt in future constructions that benefits like energy efficiency, resources and water conservation, improved indoor air quality, life cycle cost reduction and durability. This paper presents a brief study of sustainable aspects of building materials and a tool for Life Cycle Assessment criteria that helps in selecting proper building materials.
Here we present the field induced self-assembly of anisotropic colloidal particles whose shape resembles peanuts. Being made up of hematite core and silica shell, these particles align in a direction perpendicular to the applied external magnetic field. Using small-angle X-ray scattering with microradian resolution (μrad-SAXS) in sedimented samples, we have found that one can tune the self-assembled structures by changing the time of application of the external field. If the field is applied after the sedimentation, the self-assembled structure is a nematic one, while dipolar chains are formed if the field is applied during the sedimentation process. Interestingly, within each chain particles form a smectic phase with defects. Further, these aforementioned nematic and smectic phases are of oblate type in spite of the prolate shape of the individual particles. For dipolar chains, an unusual diffraction peak shape has been observed with highly anisotropic tails in the transverse direction (perpendicular to the external field). The peak shape can be rationalized by considering the fact that the dipolar chains can act as a building block aligned along the field direction to form a para-nematic phase.
The traditional bricks are the main building materials that are used extensively in the construction and building industry. Autoclaved Aerated Concrete blocks are recently one of the newly adopted building materials. The Autoclaved aerated concrete (AAC) is a product of fly ash which is mixed with lime, cement, and water and an aerating agent. The AAC is mainly produced as cuboid blocks and prefabricated panels. The Autoclaved aerated concrete is a type of concrete that is manufactured to contain lots of closed air voids. The AAC blocks are energy efficient, durable, less dense, and lightweight. It is manufactured by adding a foaming additive to concrete in different sizes of molds as per requirement, then wire-cutting these blocks or panels from the resulting ‘cake lump’ and ‘heating them with steam. This process is called as Autoclaving. It has been observed that this material is an eco-friendly building material that is being manufactured from industrial waste and is composed of non-toxic ingredients. In this paper, an overview of AAC blocks with reference to its potential and sustainability as a novel building material has been presented. The paper also presents a comparative cost analysis of AAC Blocks with the Red clay bricks and its suitability and potential use in the construction in the building industry.
The construction sector is responsible for the 40% of consumed resources, 40% of CO2 emissions, and approximately 40% of construction and demolition waste. For the assessment of the building, there exists a standardized method, life cycle assessment (LCA), however, the process requires time, cost, and most importantly expertise. In this paper, a method is proposed and analyzed for the life cycle assessment of the building for the embodied carbon in the three stages, construction, operation, and demolition. Moreover, the result of the analysis is considered as the base result, and de-carbonization strategies identified through literature study for the three stages of construction, operation, and demolition are assessed with the same method to know how much each strategy will be effective in minimizing the embodied carbon. For the base case, a high-rise residential building in an urban region of India is analyzed, based on existing conditions through the building information modeling (BIM) method. The carbon emission of the selected building comes out to be 414 kg CO2e/m2/year, and assessing different decarbonization strategies, considering the first analysis as the baseline, it can be minimized to 135 kg CO2e/m2/year.
The environment demands a reduction in greenhouse gas (GHG) emissions, as building and construction are responsible for more than 40% of the energy consumed worldwide and 30% of the world’s GHG emissions. Many countries have aligned themselves with the Paris agreement, following its target of achieving net zero carbon emissions, although some governments are focused on the operational energy efficiency part of the equation instead of the whole equation. This study emphasizes the significance of incorporating the minimization of embodied emissions into all parts of the building, with a focus on the measurement of embodied carbon, concepts of its management and strategies proposed and enacted for mitigation. As estimate is an important part of any debate, the measurement approach covers the uncertainty analysis from diverse points of view through a novel approach; management covers the early design tools, and the significance of the lifecycle stages; mitigation covers the reduction strategies of embodied carbon, although reduction in embodied carbon is a subjective topic and depends on region. The analysis covers the ideal approaches for mitigation irrespective of the region.
The main purpose of this paper is to examine the development and current status of prefabrication techniques and their application in building construction and why its use is still limited in the housing sector in India and why prefabrication is not being used so far to provide affordable housing to all. Prefabrication is the practice of assembling components of a structure in factories, and then transporting the complete assemblies or sub-assemblies to the construction site where the structure is to be located. The important aspect is how much of a potential difference it can establish so that appropriate development can be implemented. This paper reviews the current prefabrication system scenario for housing in India. The paper begins with a brief introduction about different types of prefabrication system. Subsequent topics address the need of prefabrication and ethical dilemma of technology transfer for prefabricated building system in India. In this paper, a qualitative descriptive evaluation research method has been used. The research methodology comprises of case studies, visual observation and data collection. Finally, two case studies around the world have been presented to validate and illustrate the various modern trends and application of design and construction methods of prefabricated building system in housing.
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