Sub-grade characteristics of soil stabilized with agricultural waste,constructional waste,and lime

Bulletin of Engineering Geology and the Environment - The waste generated from the agriculture and construction sector is a serious threat to the environment due to its disposal problems. This...     

Adsorption for removal of Cd(II) from effluents

The adsorption of Cd(II) onto wollastonite has been reported. Adsorption increased from 55.7 to 93.6% by decreasing the concentration of Cd(II) from 2.0 x 10^‐4M to 0.5 x 10^‐4M. The rearranged Lagergren equation has been used for dynamic modelling of the process. However, the value of rate constant at 30°C was found to be 3.17 x 10^‐2min^‐1. Equilibrium modelling was carried out using the Freundlich isotherm equation and constants have been calculated. Thermodynamic studies were carried out and values of standard free energy (?G°), enthalpy (?H°) and entropy (AS°) were calculated at various temperatures. Low temperatures favour the uptake of Cd(II) in the process.     

New correlations for estimation of monthly average daily solar radiation on a horizontal surface using meteorological data

This study deals with the estimation of monthly average daily global solar radiation incident on a horizontal surface at a location using meteorological data for different cities of Andhra Pradesh state. The regression equations of two types of models are developed for various locations of the state having varied climatic regions using measured meteorological parameters obtained from different measuring stations. Parameters such as the latitude and height of the location, maximum and minimum temperature and relative humidity are considered to develop linear and quadratic regression equations to estimate the monthly average daily global radiation. The estimated values are compared with measured data and with other theoretical models in terms of mean percent errors calculated using recognised statistical criteria of MBE, MABE, MPE and RMSE. The proposed quadratic model performs better than the proposed linear models and shows good agreement with the long-term pyranometer data of various locations with a deviation of less than 10%. In comparison with other theoretical models presented so far, the suggested models are expected to perform with a higher degree of accuracy.     

An evaluation tool for design quality: PFI sheltered housing

The complex procurement process entailed by the private finance initiative (PFI) means that clients need new capacities to manage their relationships with bidders and to assess project proposals if the desired level of design quality is to be achieved. To assist local authorities in their client role, a new Architectural Design Quality Evaluation Tool was developed. The aim was to improve the quality of design in residential sheltered housing, procured through the PFI. The tool was developed for and applied to a programme that will see the replacement of a local authority's entire sheltered housing stock. The tool has two functions: (1) to inform the client's assessment process and assist with the selection of the preferred bidding consortium through a series of stages in the PFI process; and (2) to improve the quality of all the submitted designs through an iterative process. Although several existing mechanisms are available for evaluating the performance attributes of buildings, few also tackle the less tangible amenity attributes, which are vital to the feeling of home. The new tool emphasizes the amenity attributes without neglecting performance.     

Apatite accumulation enhances the mechanical property of anammox granules

The strength of granular sludge is essential for the mechanical stability of the granules. Inorganic precipitants form a major factor influencing the strength of the granules. To check the possibility of apatite accumulation in anammox granules, and study its contribution to the mechanical strength of granules, anammox granular sludge was collected from Dokhaven municipal wastewater treatment plant, the Netherlands. Mineral precipitation inside the granules was visualized by micro-computed tomography, and apatite was identified by electron probe microanalysis and X-ray powder diffraction. The mechanical strength of anammox granules was measured by a low load compression tester. The contribution of apatite to the mechanical strength was evaluated by the generalized Maxwell model. Ca–PO₄ minerals are reported to accumulate in anammox granules. A transformation of Ca–PO₄ happens, and apatite is the final stable form. The accumulation of apatite increases the mechanical strength of anammox granules. A fast method to monitor and evaluate the accumulation of minerals in anammox granules was proposed.     

Microstructural and Tribological Behavior of Pulse Electroplated Nickel Barrier on Copper Conductors

The microstructural, mechanical, and tribological behaviors of electroplated Ni on Cu conducting substrates have been investigated in this study. The microstructural studies were performed by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The results showed that initially (111) with (220), (200) Ni texture components were predominant in the coating, and increasing the current density from 0.1 to 0.5 A/cm² led to the development of a strong (111) texture. The presence of ultrafine grains coupled with a (111) Ni texture improved the coating microhardness and wear properties significantly. It was shown that with an increase in current density, wear resistance of the coatings improved significantly and the electrical resistivity increased due to the highly populated grain boundaries.     

Fuzzy set based cost model of additive manufacturing with specific example of selective laser sintering

A fuzzy set based cost model for additive manufacturing is proposed. The model is illustrated through an example of selective laser sintering (SLS), a commonly used additive manufacturing (AM) process. Initially, a deterministic cost model is developed. It is then converted to a fuzzy set based model by considering uncertainty in build time estimation and cost components. For the specific case of SLS, a build time estimation procedure is developed as a part of the cost model. A method to evaluate the reliability of the cost estimate in AM and its significance is also introduced. The cost model is illustrated through two examples of products manufactured by SLS.

     

Hydraulic System Component Storage with Military Hydraulic Fluids

In the military aerospace community, most hydraulic fluid pumps and components are currently being stored in rust inhibited fluids containing barium dinonylnaphthalene sulfonate (BSN). Fluids containing barium are hazardous waste after use, with expensive disposal, and have caused operational problems in aircraft hydraulic systems including helicopters and fighter aircraft. In this program, bearings and pistons were stored in jars containing both operational hydraulic fluids (MIL-PRF-83282, MIL-PRF-87257, and MIL-PRF-5606) and rust-inhibited hydraulic fluids containing BSN (MIL-PRF-46170 and MIL-PRF-6083). In addition, hydraulic pumps were filled with MIL-PRF-83282, MIL-PRF-87257, and MIL-PRF-46170. Hydraulic pumps were not filled with MIL-PRF-5606 or MIL-PRF-6083 because these hydraulic fluids are being phased out of military aerospace applications as operational and storage fluids, respectively. Jars, containing bearings and pistons, as well as hydraulic pumps, were stored for up to three years in a laboratory environment to determine if operational fluids would protect them from rusting during storage. After each year, the bearings, pistons, and pumps were inspected for corrosion. At the end of three years of storage, pumps were endurance tested using fresh operational fluid, MIL-PRF-83282. The bearings, pistons, and pumps showed no rusting for the duration of storage with either operational or storage fluids. The pumps stored with the operational fluids, MIL-PRF-83282 and MIL-PRF-87257, were in better condition than the pump stored with the rust-inhibited fluid. The operational hydraulic fluids, MIL-PRF-83282 and MIL-PRF-87257, provided excellent protection against rusting during storage.

     

The Stability Margin of a Roughened Hole-Entry Hybrid Journal Bearing System

The present work describes a theoretical investigation into the effect of surface roughness on the stability margin of an orifice-compensated, hole-entry hybrid journal bearing system. A modified form of the average Reynolds equation is used for the solution of a lubricant flow field in the clearance space of a rough journal bearing system. The effects of surface roughness parameter (Λ), variance ratio (V?_rj), and the surface orientations (γ) on the bearing flow, load-carrying capacity, and stability threshold speed margin are studied. The study indicates that the bearing configurations having surface roughness on one of the opposing surfaces (stationary or moving roughness) show an opposite trend between stability threshold speed margin and load-carrying capacity. However, the bearing configurations having transverse- and isotropic-type roughness patterns on both bearing and journal surfaces provide an improved value of both stability threshold speed margin and load-carrying capacity only when the surface roughness has a variance ratio value between 0.49 and 0.59 for the transverse roughness pattern and between 0.59 and 0.84 for the isotropic roughness pattern.     

A Study of Non-Recessed Hybrid Flexible Journal Bearing With Different Restrictors

For bearings operating under heavy loads, the elastic deformation of bearing surface induced by fluid film pressures can no longer be neglected as it is comparable to the order of magnitude of fluid film thickness. In the present work a theoretical study describing comparative performance of non-recessed hybrid journal bearing using different flow control devices has been carried out by considering bearing shell flexibility into the analysis. The relevant governing equations have been solved using finite element method. The comparative performance of non-recessed hybrid journal bearings of two separate configurations have been studied for various values of bearing flexibility parameter (([Cbar]_d)). The results have been presented for hole-entry type journal bearings compensated by capillary, orifice and constant flow valve restrictors and for a slot-entry type journal bearing, for the same set of values of operating and geometric parameters. The computed results indicates that in order to get an improved performance of non-recessed journal bearing, a proper selection of bearing flexibility parameter (([Cbar]_d)) along with type of flow control device (i.e., capillary, orifice, constant flow valve, slot etc.) and type of bearing configuration (symmetric/asymmetric) are essential.