A modified laboratory approach to determine reaeration rate for river water

It is reported that reaeration rates determined from laboratory investigation may not suit well in predicting reaeration rate of natural streams. Sampling method during reaeration experiment is a potential source of error in laboratory estimation of reaeration rate coefficient for river waters, which has been addressed in this research. A modified method based on sampling procedure in a flume was adopted to develop a reaeration rate equation for Pusu River in Malaysia,which is demographically a very important river. An important feature including several culverts along the course of the river was also considered to model dissolved oxygen (DO) concentration.DOwas calibrated and validated using water quality analysis simulation program (WASP) considering appropriate kinetic rate coefficients for Pusu River. Performance of the new reaeration rate equation and other process equations in the calibration and validation data was assessed in terms of root-mean-square error (RMSE), mean error between observed and predicted data and R2 value. Study results revealed that the equation developed in B Abdullah Al-Mamun [email protected] Md Nuruzzaman [email protected] http://waterzaman.weebly.com/ Md Noor Bin Salleh [email protected] 1 Department of Civil Engineering, Rangpur Engineering College, Rangpur 5403, Bangladesh 2 Department of Civil Engineering, Kulliyyah of Engineering, International Islamic University Malaysia (IIUM), 53100 Kuala Lumpur, Malaysia 3 Bioenvironmental Engineering Research Center (BERC), Kulliyyah of Engineering, International Islamic University Malaysia (IIUM), 53100 Kuala Lumpur, Malaysia this research considering the impact of culverts on reaeration rate predicted DO in Pusu River with improved accuracy as compared to the other equations. RMSEs were found to be 0.083 and 0.067 mg/L for calibration and validation data, respectively. Mean errors of observed and model-predicted data were 0.06 and 0.05 mg/L for calibration and validation,respectively. The R2 value was 0.99 in both cases. The study results facilitate accuracy in future studies on DO of Pusu River

Shape Memory Polyurethane-Based Smart Polymer Substrates for Physiologically Responsive, Dynamic Pressure (Re)Distribution.

Shape memory polymers (SMPs) are an exciting class of stimuli-responsive smart materials that demonstrate reactive and reversible changes in mechanical property, usually by switching between different states due to external stimuli. We report on the development of a polyurethane-based SMP foam for effective pressure redistribution that demonstrates controllable changes in dynamic pressure redistribution capability at a low transition temperature (∼24 °C)-ideally suited to matching modulations in body contact pressure for dynamic pressure relief (e.g., for alleviation or pressure ulcer effects). The resultant SMP material has been extensively characterized by a series of tests including stress-strain testing, compression testing, dynamic mechanical analysis, optical microscopy, UV-visible absorbance spectroscopy, variable-temperature areal pressure distribution, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, differential scanning calorimetry, dynamic thermogravimetric analysis, and 1H nuclear magnetic resonance spectroscopy. The foam system exhibits high responsivity when tested for plantar pressure modulation with significant potential in pressure ulcers treatment. Efficient pressure redistribution (∼80% reduction in interface pressure), high stress response (∼30% applied stress is stored in fixity and released on recovery), and excellent deformation recovery (∼100%) are demonstrated in addition to significant cycling ability without performance loss. By providing highly effective pressure redistribution and modulation when in contact with the body's surface, this SMP foam offers novel mechanisms for alleviating the risk of pressure ulcers

Synthesis of superhydrophobic polymer/tungsten (VI) oxide nanocomposite thin films

A method is presented to enable the preparation of superhydrophobic polymer/tungsten (VI) oxide (WO3) nanocomposite coatings on glass substrates. WO3 nanoparticles were incorporated via the swell-encapsulation-shrink method into superhydrophobic silicone polymer films deposited on glass via aerosol-assisted chemical vapour deposition (AACVD) to produce the novel nanocomposite films. The technique overcomes the limitations of previous methods for nanoparticle incorporation to provide a synthetic route to previously unattainable materials. The nanocomposite films retain the properties of the superhydrophobic polymer while the presence of the nanoparticles is clearly evident. As such, the films have a range of potential applications including high surface area photocatalysis and self-cleaning photochromic or electrochromic coatings. The two-stage synthesis is shown to be flexible and suggests great scope for producing any number of future novel materials. The thin films were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS), infra-red (FTIR) spectroscopy, X-ray diffractometry (XRD) and water droplet contact angle measurements

Determining ammonia nitrogen decay rate of Malaysian river water in a laboratory flume

There is lack of information regarding ammonia nitrogen (AN), (i.e. NH3-N) decay rate of river water in tropical regions like Malaysia. AN decay rate is a very important kinetic parameter to estimate NH3-N, nitrate nitrogen (NO3-N) and dissolved oxygen concentrations of river water by using computer models. This study presents determination of ammonia nitrogen decay rate of river water in the tropical environment of Malaysia. A laboratory flume was used to conduct twelve experiments. The flume was used to represent the turbulent condition of a typical river. Ammonia nitrogen decay rate for the tropical environment of Malaysia was observed to be between 0.194 and 0.554 per day. Median value of AN decay rate was 0.26 per day, which is slightly lower than the global median value of 0.295 per day. To check the accuracy of flume experiments, the AN decay rate of Pusu River obtained from the flume experiment was used to calibrate and validate ammonia nitrogen concentration of the river by using water quality analysis and simulation program (WASP). Very good calibration and validation results were achieved, which substantiated the accuracy of the flume experiments

Impediments to river rehabilitation

Rehabilitation of river ecosystems is generally initiated when a river is no longer able to provide benefits to humans and other living beings. The major purposes of river rehabilitation projects are improving water quality, conserving nature, rehabilitating fisheries and riparian habitats, flood mitigation, and creating recreational opportunities.For a river rehabilitation project to be successful,it must have specific and clearly explained objectives, although these objectives will vary for each project depending upon factors such as economics, public demand,ecosystem benefits, and the like. In this article, we provide a critical analysis of the purposes that drive river rehabilitation projects and we identify and discuss impediments that can cause a project to deviate from its intended goals. We also discuss major constraints on rehabilitation efforts that can result in failed projects

A brief account of river rehabilitation experiences

Rivers are vital water resources which are being altered due to urbanization and industrialization, causing threats to the environment. As a result, rehabilitation of polluted rivers has gained great importance during the last century in many countries of the world. Literature on river rehabilitation projects has been reviewed in this paper, highlighting the experiences gathered in the developed nations of the world; such as the USA, the UK, Japan, etc. Rehabilitation issues of the rivers crossing borders have also been discussed in this paper. Key lessons from different experiences in different regions have been extracted and a comparison has been made. Summarised statistics on different experiences also have been presented. Finally, some guidelines have been provided based on various experiences, which should be helpful for developed and developing nations while making their river rehabilitation efforts

UPGRADING OF SMALL SEWAGE TREATMENT PLANTS FOR AMMONIA REMOVAL -CASE OF A UNIVERSITY CAMPUS

ABSTRACT Fourteen small sewage treatment plants (STPs) are constructed to treat the sewage generated from the International Islamic University Malaysia (IIUM) Gombak campus. These plants are required to fulfil the effluent Standard B of the revised environmental quality act of Malaysia. Effluent quality data of these plants was evaluated to check the compliance with the revised effluent quality standards set by the Department of Environment (DOE), Malaysia. Secondary data (monthly) of the STPs was analysed for this study. Performance of the STPs were evaluated in terms of ammoniacal nitrogen (AN) and biochemical oxygen demand (BOD). The statistical analyses of the data revealed that the median effluent concentration of AN from all the plants usually fails to meet the allowable concentration of 20 mg/L set for Standard B. However, all of the plants are able to meet the BOD standard of 50 mg/L. This study recommends additional aeration for extended time to reduce AN concentration from the effluents of the existing plants. Another alternate solution is to construct a centralized treatment plant, preferably a sequenced batch reactor (SBR), to provide further treatment of effluent released from the existing small plants, which are unable to meet the standard set for allowable AN concentration

A BRIEF ACCOUNT OF RIVER REHABILITATION EXPERIENCES

Rehabilitation of polluted rivers has gained great importance to many countries in the world since the last century as the river is a vital water resource and it is being altered because of urbanization and industrialization causing great threat to the environment. Literatures on river rehabilitation projects have been reviewed focusing on the developing part of the world such as USA, UK, Japan etc. Rehabilitation issues of rivers crossing borders have also been discussed in this paper. Key lessons from different experiences in different regions have been extracted and comparison has been done. Statistics on different experiences has also been presented. Finally, some guidelines have been provided based on different experiences, which should be helpful for developed and developing nations making river rehabilitation efforts

Tensile Properties of Glass Fiber Reinforced Polyamide 6-Polypropylene Composites

In this research study, glass fiber (GF) reinforced polyamide 6 (PA6)-polypropylene blends were prepared using injection molding machine. Test specimens of five different compositions such as, 70%PA6+30%PP, 65%PA6+30%PP+5%GF, 60%PA6+30%PP+10%GF, 55%PA6+30%PP+15%GF and 50%PA6+30%PP+20%GF were prepared successfully. The effects of glass fiber content on the tensile properties of the composites were investigated. Test results reveal that yield strength, elastic modulus, tensile strength and tensile elongation are influenced by glass fiber content. Results show that yield strength is low for 70%PA6+30%PP pure polymer blend whereas 50%PA6+30%PP+20%GF composite shows high yield strength. Test results also show that elastic modulus is low for 70%PA6+30%PP, it increases with the increase in fiber content and elastic modulus is remarkably high for 50%PA6+30%PP+20%GF composite. On the other hand, tensile strength is low for 70%PA6+30%PP blend and tensile strength of GF reinforced composite increases steadily with the increase in glass fiber content. In addition, the tensile elongation of 70%PA6+30%PP pure blend is very high, whereas the composite shows reduced tensile elongation with the increase in fiber content and particularly, 50%PA6+30%PP+20%GF composite shows notably low tensile elongation

Influence of glass fiber content on tensile properties of polyamide-polypropylene based polymer blend composites

In recent years, the rapid development of polymer composites is replacing the use of metals and alloys in high performance engineering applications, particularly in automotive and aerospace industries. In this research study, influence of glass fiber (GF) content on tensile properties of polyamide-polypropylene (PA-PP) based blend composites was investigated. Considering, 0%, 3%, 6%, 9% and 12% GF content, PA6-PP-GF composites of five compositions were prepared through injection molding method. In the experiments, tensile tests were performed under strain rate of 5 mm/min for all types of composite specimens. Test results show that tensile properties of composites of five different compositions are influenced by glass fiber content. In general, tensile strength of composite increases gradually with increase in fiber content. On the other hand, tensile modulus increases significantly with increase in fiber content. Experimental data also revealed that yield strength, strength at fracture and strain at break of the composites are influenced by the content of glass fiber. Test data also show that tensile strain at maximum load almost corresponds to the tensile strain at break for all composite specimens