The effect of the pH of the testing liquid on the slake durability of gypsum

It is known that foundation problems are caused by the dissolution of gypsum due to both chemical and mechanical processes. In order to investigate the combined effect of physico-chemical agents on the erodability of gypsum, a series of slake durability tests were carried out on eight different types of gypsum using testing solutions with different pH values. XRD, chemical and petrographical analyses, and basic strength tests such as unconfined compression, Brazilian tensile, and point load were performed on the eight rock types. The slake durability results ranged from medium to very high under the different pH conditions but it was concluded that the slake durability of gypsum is independent of the pH of the testing solution. Mineralogical composition and fabric are considered to have a greater influence on the slake durability of gypsum.     

Renewable energy in India: Historical developments and prospects

Promoting renewable energy in India has assumed great importance in recent years in view of high growth rate of energy consumption, high share of coal in domestic energy demand, heavy dependence on imports for meeting demands for petroleum fuels and volatility of world oil market. A number of renewable energy technologies (RETs) are now well established in the country. The technology that has achieved the most dramatic growth rate and success is wind energy; India ranks fourth in the world in terms of total installed capacity. India hosts the world's largest small gasifier programme and second largest biogas programme. After many years of slow growth, demand for solar water heaters appears to be gaining momentum. Small hydro has been growing in India at a slow but steady pace. Installation of some of the technologies appears to have slowed down in recent years; these include improved cooking stoves (ICSs) and solar photovoltaic (PV) systems. In spite of many successes, the overall growth of renewable energy in India has remained rather slow. A number of factors are likely to boost the future prospects of renewable energy in the country; these include global pressure and voluntary targets for greenhouse gas emission reduction, a possible future oil crisis, intensification of rural electrification program, and import of hydropower from neighbouring countries.     

Improved Method for Approximation of Heating and Cooling Load in Urban Buildings for Energy Performance Enhancement

Abstract

Estimation of a building’s heating and cooling loads is an important factor taken into account implementation of energy saving measures in order to enhance energy performance of the building. In this work, the heating and cooling loads are predicted to enhance the building energy performance using different types of artificial neural networks namely, Elman network, recurrent network and back propagation network. The effect of eight input variables (relative compactness, surface area, wall area, roof area, overall height, orientation, glazing area, glazing area distribution) on two output variables (heating load and cooling load of residential buildings) is studied. The collected features are given as input to various neural networks for predicting the heating and cooling loads. The performance of the method is calculated in terms of mean absolute error, mean square error and mean relative error. Among all the networks back-propagation neural network has highest accuracy. The mean absolute error in predicting the loads is found to be 0.1 for heating load and 0.1254 for cooling load which is much better than already existing methods. The results of the work further reinforce the fact that ANN is an important tool for prediction and analysis of energy performance of a building.     

Collapse simulation of reinforced concrete frame structures

Study of collapse‐resisting properties of structures has attracted widespread attention because of frequently occurring earthquakes and extreme events (e.g. blast) around the world. The developments in computational methods have enabled researchers to numerically simulate the collapse of structures under different kinds of loadings and provide reliable assessments of the collapse performance of structures. The dynamic nature of structural collapse requires a direct integration algorithm to solve the equations of motion of the numerical simulation model. A major concern in such simulations is the computational efficiency, which stems from the need to use a small time step size in both implicit algorithm and explicit algorithm. In this paper, modeling techniques to simulate typical failure mechanisms in reinforced concrete frame structures combined with the application of the recently developed explicit, unconditionally stable, parametrically dissipative KR‐α integration method to investigate collapse simulation are presented. A fiber beam‐column element is used to model the frame members, where the material nonlinearities, especially material softening, are simulated by a plastic damage model combined with a failure criterion. Numerical examples are presented to illustrate the proposed collapse simulation technique. The results indicate that the proposed technique provides an accurate result and has exceptional computational efficiency. Copyright © 2015 John Wiley & Sons, Ltd.     

Study of the effect of different weave constructions on the drapeability of jute woven fabric

The growing global concern for environment on one hand and the alarming danger of carbon footprint generation along with non-biodegradability and higher toxicity generation from the use of synthetic fibres on the other have created a dire need to come back to natural fibres. During the application of fabrics at the sites for geotextile application and even in designing garments in the apparel sector, it has been observed that the ability of the fabric to assume a graceful appearance of the contour is very crucial in conveying the significance of drapeability of the natural fibre-made fabric. An attempt has been made in this work to evaluate the effect of different weave constructions on the drapeability of jute-woven fabrics to justify their application on the sites.     

Studies of lagoon ash from Sarawak to assess the impact on the environment

Coal utilization, mainly in thermal power plants, has increased significantly from 4.2 to 13 million tonnes within 2000 to 2005, which resulted in the production of approximately 2 million tonnes of coal ash in Malaysia. Of this only a small percentage is used as a cement ingredient, in concrete industry, as a fill material, etc. and with the rest of the amount being disposed in ash ponds or lagoons. If the lagoons are not properly designed with a landfill liner or if there is spillage from the ash pond, the toxic heavy metal present in coal ash can result in the contamination of the subsurface soil and the ground water. The concentration of heavy metals or trace elements in coal residues depends on the composition of a particular parent coal and the bulk utilization of lagoon ash for various purposes requires a complete characterization of the ash. Hence, this paper analyzes the coal ash for its trace element content and characterizes mainly physical, chemical, mineralogical, morphological and thermal properties of the lagoon ash from a local coal based thermal power plant from Sarawak, Malaysia. The results also indicated that, the concentration of some trace elements is quite high from the environmental perspective in this particular lagoon ash.     

Cellular automata-based forecasting of the impact of accidental fire and toxic dispersion in process industries

The strategies to prevent accidents from occurring in a process industry, or to minimize the harm if an accident does take place, always revolve around forecasting the likely accidents and their impacts. Based on the likely frequency and severity of the accidents, resources are committed towards preventing the accidents. Nearly all techniques of ranking hazardous units, be it the hazard and operability studies, fault tree analysis, hazard indice, etc.--qualitative as well as quantitative--depend essentially on the assessment of the likely frequency and the likely harm accidents in different units may cause. This fact makes it exceedingly important that the forecasting the accidents and their likely impact is done as accurately as possible. In the present study we introduce a new approach to accident forecasting based on the discrete modeling paradigm of cellular automata. In this treatment an accident is modeled as a self-evolving phenomena, the impact of which is strongly influenced by the size, nature, and position of the environmental components which lie in the vicinity of the accident site. The outward propagation of the mass, energy and momentum from the accident epicenter is modeled as a fast diffusion process occurring in discrete space-time coordinates. The quantum of energy and material that would flow into each discrete space element (cell) due to the accidental release is evaluated and the degree of vulnerability posed to the receptors if present in the cell is measured at the end of each time element. This approach is able to effectively take into account the modifications in the flux of energy and material which occur as a result of the heterogeneous environment prevailing between the accident epicenter and the receptor. Consequently, more realistic accident scenarios are generated than possible with the prevailing techniques. The efficacy of the approach has been illustrated with case studies.     

Spur line integrated single‐/dual‐/triple‐notched ultra‐wideband monopole antenna

Design and realization of spur line loaded frequency‐notched planar ultra‐wideband (UWB) antenna is proposed in this article. Accommodating the spur line (lines) of quarter wavelength long on the feeding microstrip line of UWB antenna, contributes to the notch‐filtering action in the feeding section itself which in turn can provides single/double/triple notch (notches) within the UWB spectrum of the antenna. The proposed technique is very simple and radiator independent as the filtering is performed in the feed region and hence the UWB radiator can be independently designed. The spur line based filtering sections are first separately designed and verified by S‐parameter measurements of the fabricated prototypes. Single, double, and triple spur line loaded microstrip sections are separately used as the feed section of a circular monopole antenna (MPA) to invoke single‐, dual‐, and triple‐notched UWB response of the MPA. All the designed prototypes are fabricated and characterized in terms of impedance and radiation parameter measurements, yielding very close correspondence with that of results obtained from full wave simulation.     

An Evaluation of Drapeability of Jute Fabric

From the very inception of the Indian Jute Industry, jute fiber has proved its superiority over other fibers particularly in the area of packaging for food grains, in terms of its functionality and reusability due to its considerable tensile strength, low extensibility, and good dimensional stability, which is obviously the natural choice for packaging. One of the growing alternatives in today’s context is the emergence of technical textiles made out of natural fibers which includes geotextile products for geotechnical applications, agrotextile products as well as other such relevant areas. Jute geotextile can certainly be considered as a potential aspirant replacing majority of today’s popular synthetic products which are posing severe threats to our environment thereby adversely affecting the eco-congruity. During the application of jute fabrics of different types at the sites and even in designing garments in the Apparel Sector, it has been observed that the ability of the fabric to assume a graceful appearance of the contour is very crucial conveying the significance of drapeability of the jute fabric. An attempt has been made in this paper to study the effect of relevant property parameters and their comparative analysis on the drapeability of jute fabric as well as synthetic woven and nonwoven fabrics with respect to their end-use requirements.