Biological phenol removal using immobilized cells in a pulsed plate bioreactor: effect of dilution rate and influent phenol concentration

The continuous aerobic biodegradation of phenol in synthetic wastewater was carried out using Nocardia hydrocarbonoxydans immobilized over glass beads packed between the plates in a pulsed plate bioreactor at a frequency of pulsation of 0.5s(-1) and amplitude of 4.7 cm. The influence of dilution rate and influent phenol concentration on start up and steady state performance of the bioreactor was studied. The time taken to reach steady state has increased with increase in dilution rate and influent phenol concentration. It was found that, as the dilution rate is increased, the percentage degradation has decreased. Steady state percentage degradation was also reduced with increased influent phenol concentration. Almost 100% degradation of 300 and 500 ppm influent phenol could be achieved at a dilution rate of 0.4094 h(-1) and more than 99% degradation could be achieved with higher dilution rates. At a higher dilution rate of 1.0235 h(-1) and at concentrations of 800 and 900 ppm the percentage degradation has reduced to around 94% and 93%, respectively. The attached biomass dry weight, biofilm thickness and biofilm density at steady state were influenced by influent phenol concentration and dilution rate.     

Raft-forming agents: antireflux formulations

Gastroesophageal reflux disease (GERD) is caused by excessive reflux of gastric content and duodenal bile into the esophagus, and impaired clearance of refluxate from the esophagus. In this perspective, raft-forming antireflux formulations offer better alternatives to the conventional therapies for treatment of uncomplicated GERD. In addition to the alginate-based systems, various natural polysaccharides have generated interest as raft-forming agents because of their bioadhesive/mucoprotective nature. Inclination of current therapy is towards natural products for healing of the disease, which also underlines the market potential of this class, demanding for thorough investigation and development of evaluation methods with better in vitro-in vivo correlation.     

Fruit and Vegetable Waste: Bioactive Compounds,Their Extraction,and Possible Utilization

Fruits and vegetables are the most utilized commodities among all horticultural crops. They are consumed raw, minimally processed, as well as processed, due to their nutrients and health‐promoting compounds. With the growing population and changing diet habits, the production and processing of horticultural crops, especially fruits and vegetables, have increased very significantly to fulfill the increasing demands. Significant losses and waste in the fresh and processing industries are becoming a serious nutritional, economical, and environmental problem. For example, the United Nations Food and Agriculture Organization (FAO) has estimated that losses and waste in fruits and vegetables are the highest among all types of foods, and may reach up to 60%. The processing operations of fruits and vegetables produce significant wastes of by‐products, which constitute about 25% to 30% of a whole commodity group. The waste is composed mainly of seed, skin, rind, and pomace, containing good sources of potentially valuable bioactive compounds, such as carotenoids, polyphenols, dietary fibers, vitamins, enzymes, and oils, among others. These phytochemicals can be utilized in different industries including the food industry, for the development of functional or enriched foods, the health industry for medicines and pharmaceuticals, and the textile industry, among others. The use of waste for the production of various crucial bioactive components is an important step toward sustainable development. This review describes the types and nature of the waste that originates from fruits and vegetables, the bioactive components in the waste, their extraction techniques, and the potential utilization of the obtained bioactive compounds.     

Machine fault diagnosis using a cluster-based wavelet feature extraction and probabilistic neural networks

In this paper, a cluster-based feature extraction from the coefficients of a discrete wavelet transform and probabilistic neural networks are proposed for machine fault diagnosis. The proposed approach first divides the matrix of wavelet coefficients into clusters, which are centered around the discriminative coefficient positions identified by an unsupervised procedure, based on the entropy value of coefficients from a set of representative signals. The features that contain the informative attributes of the signals are computed from the energy content of the obtained clusters. Then, machine faults are diagnosed based on these feature vectors using a probabilistic neural network. The experimental results from the application on bearing fault diagnosis have shown that the proposed approach is able to effectively extract important intrinsic information content of the test signals and increase the overall fault diagnostic accuracy, as compared to conventional methods.     

Virucidal efficacy of sodium bicarbonate on a food contact surface against feline calicivirus, a norovirus surrogate

Norovirus-associated foodborne outbreaks have become a major public health concern all over the world. Food service establishments are always looking for disinfectants and sanitizers that are effective against various microbes but are non-corrosive and non-toxic to food and food contact surfaces. The efficacy of sodium bicarbonate against certain bacteria and fungi has been documented but its role as a disinfectant against viruses is not known. In this study, anti-calicivirus efficacy of sodium bicarbonate alone and in combination with aldehydes or hydrogen peroxide was evaluated using feline calicivirus (FCV) as a surrogate for norovirus (NoV). Sodium bicarbonate at concentrations of 5% and above was found to be the most effective with 4 log(10) (99.99%) reduction in FCV titers on food contact surfaces within a contact time of 1 min. The virucidal efficacy of sodium bicarbonate was enhanced when it was used in combination with aldehydes or hydrogen peroxide. An advantage of sodium bicarbonate over the available chemical disinfectants for food contact surfaces is its safety, ready availability and low cost. The use of sodium bicarbonate alone or in combination with aldehydes can be an effective and inexpensive method of disinfecting food contact surfaces.     

A terrestrial biotic ligand model. 1. Development and application to Cu and Ni toxicities to barley root elongation in soils

A Terrestrial Biotic Ligand Model (TBLM) was developed using noncalcareous soils from Europe based on Cu and Ni speciation and barley (Hordeum vulgare cv. Regina) root elongation bioassays. Free metal ion (M2+) activity was computed by the WHAM VI model using inputs of soil metal, soil organic matter, and alkali and alkaline earth metals concentrations, and pH in soil solution. The TBLM assumes that metal in soil and in the solution are in equilibrium. Metal ions react with the biotic ligand, the receptor site, and inhibit root elongation. Other ions, principally H+, Ca2+ and Mg2+, compete with M2+ and, therefore, affect its toxicity. Toxicity is correlated only to the fraction of the total biotic ligand sites occupied by M2+. Compared to other models using either the soil metal concentration or M2+ activity as the toxic dose, the TBLM provides a more consistent method to normalize and compare Cu and Ni toxicities to root elongation among different soils. The TBLM was able to predictthe EC50 soil Cu and Ni concentrations generally within a factor of 2 of the observed values, a level of precision similar to that for the aquatic Biotic Ligand Model, indicating its potential utility in metals risk assessment in soils.     

Environmental radioactivity studies in the proposed Lambapur and Peddagattu uranium mining areas of Andhra Pradesh, India

The present work was aimed at the establishment of baseline radioactive data in the proposed Lambapur and Peddagattu uranium mining areas in the Andhra Pradesh state, India. The background concentrations of naturally occurring radioactivity in the near-surface soils of the study areas were estimated and the results were analysed. The (238)U concentration in the near-surface soil of the study area was found to vary from 100 to 176 Bq kg(-1), with a mean of 138±24 Bq kg(-1). (232)Th in the study area soils was found to vary between 64 and 116 Bq kg(-1), with a mean of 83±15 Bq kg(-1). The (40)K concentration was found to vary between 309 and 373 Bq kg(-1), with a mean of 343±20 Bq kg(-1). The mean natural background radiation levels were also measured with thermoluminescence (TL) dosimetry technique and with a μR-survey meter, in the villages of the study area. Dose rates measured by TL are found to vary from 1287 to 3363 μGy y(-1), with a mean of 2509 ± 424 μGy y(-1). The dose rates measured in the same villages with a μR-survey meter were found to be in the range of 1211-3255 μGy y(-1), with a mean of 2524 ± 395 μGy y(-1). The mean radiation levels in the study area are found to be relatively high when compared with (Indian) national and international averages. Correlations among radon, thoron and gamma dose rates were found to be poor. The pre-operational data produced in this work will be useful for comparison with future radiation levels during the proposed uranium mining operations.     

Potential biomass supply for agro-pellet production from agricultural crop residue in Nepal

Nepal, a country rich in biomass, still does not have any commercial pellet production plants and is wasting large amounts of agricultural crop residue. The current study showed that about 5.61 million tonnes (Mt) of biomass in the form of pellets are potentially available from agricultural crop residues. The brick and cement industries could use these agro-pellets. Co-firing of pellets in such industries could play an important role in reducing the import volume of coal and minimize the related environmental loadings.     

Modeling and Experimental Studies on 3D-Magnetic Flux Leakage Testing for Enhanced Flaw Detection in Carbon Steel Plates

ABSTRACT

For enhanced detection of flaws in engineering components using magnetic flux leakage (MFL) technique, measurement of the leakage magnetic field components along the three perpendicular directions is beneficial. This article presents the three dimensional-magnetic flux leakage (3D-MFL) modeling and experimental studies carried out on carbon steel plates. Magnetic dipole model has been used for the prediction of MFL signals and images. Sensitivity of the MFL signals peak amplitudes of tangential (H_X), circumferential (H_Y), and normal (H_Z) components with respect to flaw length, width, depth and lift-off have been studied. A 3D-GMR sensor has been used for simultaneous measurement of all the three components of leakage magnetic fields from surface flaws in 12 mm thick carbon steel plates. The experimental MFL images have been compared with the model predicted MFL images. The sensor has shown the capability to detect and image 0.9 mm deep surface flaws with a signal to noise ratio of 8 dB. Principal component analysis (PCA)-based image fusion has been performed for fusion of the 3D-MFL images to obtain a geometrical profile of the flaws. Study reveals that 3D-GMR enhances the capability for detection of flaws having irregular geometries.     

Study of different approaches for management of contaminated emulsified aqueous secondary waste

The underlying objective governing the management of radioactive waste is protection of human being and the environment, now as well as in the future. As a waste management philosophy, utmost emphasis is given to waste volume minimization at all stages of design, operation and maintenance [1]. The development of innovative treatment processes for low and intermediate level wastes (LLW and ILW) in recent times has focused on volume reduction as one of the main objectives [2]. During reprocessing of spent fuel, an optimized mixture of tri-n-butyl phosphate (TBP) and dodecane is used as an extracting agent for actinides. During their repeated use, solvent undergoes chemical/radiolytic degradation, loosing its efficiency and hence to be discarded as spent organic solvent waste. This waste is presently being treated by alkaline hydrolysis process where spent solvent is refluxed with concentrated sodium hydroxide solution at 110°C [3]. TBP component of the spent solvent waste gets hydrolyzed and is converted into sodium salt of di-butyl phosphate (DBP). The other products obtained during hydrolysis include sodium salt of mono-butyl phosphate (MBP), butanol and phosphoric acid. Dodecane component of the spent solvent waste does not take part in the hydrolysis reaction and appears as a clear phase. The dodecane waste thus separated is subjected for thermal destruction by incineration. The emulsified aqueous layer thus obtained retains most of the activity present in the spent solvent waste. The present paper describes experimental studies performed to look for various approaches for management of this type of waste.