Flocculation of river silt using chitosan

Flocculation of silt in river water using chitosan was studied in the pH range 4-9, and suspended solid concentrations in the range 20-80 mg/L. Chitosan effectively reduces turbidity due to silt by flocculation and settling. Flocculation efficiency is very sensitive to pH, and reaches a maximum at pH 7. The optimal chitosan concentration required to effect flocculation is 0.5 mg/L and is independent of silt concentration within the range examined. Restabilisation of the suspension is observed at higher concentrations of chitosan, and the amount required for restabilisation increases with increasing concentration of suspended solids. Flocculation is faster at higher concentrations of silt and the flocs are large and fibrous.     

Rambutan rind in the management of hyperglycemia

Plant extracts have been suggested as a rich as yet unexplored source of potentially useful anti-diabetic drugs. Recent scientific investigations have confirmed the efficacy of many of these preparations, as effective antioxidants; able to regenerate functional pancreatic beta cells and has a hypoglycemic potential. In this study, the exotic rambutan (Nephelium lappaceum L.) fruit's rind has been shown to be effective in inhibiting the carbohydrate hydrolyzing enzymes, alpha glucosidase (EC₅₀ = 2.7 ??g/mL) and alpha amylase (EC₅₀ = 70.8 ??g/mL), at a much more significant level than the drug acarbose (EC₅₀ = 3500 ??g/mL; alpha glucosidase; EC₅₀ = 12 ??g/mL; alpha amylase). In addition, the geraniin-enriched ethanolic extracts were able to inhibit the key enzyme in the polyol pathway, aldol reductase (EC₅₀ = 0.04 ??g/mL) and prevent the formation of advanced glycation end-products (AGE) by 43%. These findings indicate that the geraniin-standardized N. lappaceum rind may be a potential source of an anti-hyperglycemic agent.     

Human Umbilical Cord Lining-Derived Epithelial Cells: A Potential Source of Non-Native Epithelial Cells That Accelerate Healing in a Porcine Cutaneous Wound Model

Human umbilical cord lining epithelial cells [CLECs) are naïve in nature and can be ethically recovered from cords that are routinely discarded. The success of using oral mucosal epithelial cells for cornea defects hints at the feasibility of treating cutaneous wounds using non-native CLECs. Herein, we characterized CLECs using flow cytometry (FC) and skin organotypic cultures in direct comparison with skin keratinocytes (KCs). This was followed by wound healing study to compare the effects of CLEC application and the traditional use of human skin allografts (HSGs) in a porcine wound model. While CLECs were found to express all the epidermal cell markers probed, the major difference between CLECs and KCs lies in the level of expression (in FC analysis) as well as in the location of expression (of the epithelium in organotypic cultures) of some of the basal cell markers probed. On the pig wounds, CLEC application promoted accelerated healing with no adverse reaction compared to HSG use. Though CLECs, like HSGs, elicited high levels of local and systemic immune responses in the animals during the first week, these effects were tapered off more quickly in the CLEC-treated group. Overall, the in vivo porcine data point to the potential of CLECs as a non-native and safe source of cells to treat cutaneous wounds.     

RF energy harvesting systems: An overview and design issues

One of the main challenges in implementing sensor devices for internet of things (IoTs), is the means for the operating power supply. RF energy harvesting (RFEH) presents a promising solution as RF power is a suitable choice particularly for cases where solar harvesting is not feasible. However, in spite of RF communication system design being a well‐established, there are several challenges poised for the implementation of the RFEH systems especially for harvesting the ambient RF signals. The challenges can be widely categorized as the overall conversion efficiency, bandwidth, and form factor. In this article, an exhaustive survey on the different RFEH system that is reported is carried out and discussed. Important design issues are identified with insights drawn. First, we have presented the challenges in designing antennas for RFEH systems. This is followed by rectifier circuits and matching networks, and eventually a general frame work for designing of ambient RFEH systems is deduced.     

Effect of microstructural arrangement of MDI-based polyurethanes on their photoproperties

Among the vast variety of polyurethane applications, several applications use the fluorescing nature of some of the polyurethanes. Even though 4,4′-methylenebis(phenylisocyanate) (MDI)-based polyurethanes fluoresce, their applications are rare because of the lack of knowledge about the fluorescence behavior of these polymers. In this study, the fluorophores responsible for the emission spectra of MDI-based polyurethanes were identified, and their emission behavior was investigated. When excited, these polymers produce two prominent emission peaks located at 356 nm and 423 nm, which are assigned to the radiative relaxation of excited isolated hard segments and excited crystalline hard segment bundles of the MDI-based polyurethanes, respectively. It was found that both chromophores can be excited by 293 nm UV radiation. The observed intensity variations of the two peaks with exposure time were attributed to the localized UV melting-assisted migration of isolated hard segments. This migration facilitates the formation of crystalline hard segments. As the two chromophore populations are inversely propositional to each other, the relative intensity of the two emission peaks varies with UV exposure in a similar manner. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47431.     

Porous poly(ethylene glycol)–polyurethane hydrogels as potential biomaterials

We report the synthesis of porous poly(ethylene glycol)–polyurethane (PEG‐PU) hydrogels using PEG‐4000 as a soft segment and 4,4′‐methylenebis(cyclohexylisocyanate) as a hard segment. The degree of swelling in the hydrogels could be controlled by varying the amount of crosslinking agent, namely 1,2,6‐hexanetriol. Structural characterization of the hydrogels was performed using solid‐state ¹³C NMR and Fourier transform infrared spectroscopy. Wide‐angle X‐ray diffraction studies revealed the existence of crystalline domains of PEG and small‐angle X‐ray scattering studies showed the presence of lamellar microstructures. For generating a porous structure in the hydrogels, cryogenic treatment with lyophilization was used. Scanning electron microscopy and three‐dimensional micro‐computed tomography imaging of the hydrogels indicated the presence of interconnected pores. The mechanical strength of the hydrogels and xerogels was measured using dynamic mechanical analysis. The observed dynamic storage moduli (E′) for the equilibrium swollen and dry gels were found to be 0.15 and 4.2 MPa, respectively. Interestingly, the porous PEG‐PU xerogel also showed E′ of 5.6 MPa indicating a similar mechanical strength upon incorporating porosity into the gel matrix. Finally, preliminary cytocompatibility studies showed the ability of cells to proliferate in the hydrogels. These gels show promise for applications as scaffolds and implants in tissue engineering. © 2014 Society of Chemical Industry     

The effect of change of ionomer/polyol molar ratio on dispersion stability and crystalline structure of films produced from hydrophilic polyurethanes

In this study, we report the effect of the DMPA/PTHF molar ratio on dispersion properties of the MDI‐based hydrophilic polyurethane dispersions. In addition, the effect of the DMPA/PTHF molar ratio on the crystallinity and thermal properties of the polyurethane films prepared from dispersions are also discussed. The variation in stability was studied using a particle size analyzer. DSC and XRD analyses were used to study variations in crystallinity of films with the change of DMPA/PTHF molar ratio. FT‐IR spectra were used to monitor the formation of hydrogen bonds through urethane linkages to produce hard‐segment crystalline areas. The zeta potential increased with the increase of DMPA/PTHF molar ratio (hard‐segment content), while particle size of polyurethane particles decreased. Hence, the stability of dispersions was increased with DMPA/PTHF molar ratio due to the increase of hydrophilicity in polymer chain. Crystallinity of the films was increased with DMPA/PTHF molar ratio due to the increase of interchain interactions through Coulombic interactions and hydrogen bonding. Consequently, crystalline melting temperature was increased with the increase of DMPA/PTHF molar ratio. However, molten films formed crystalline soft segments instead of crystalline hard segments during slow cooling. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44475.     

Enhancing multimodal disaster tweet classification using state-of-the-art deep learning networks

During disasters, multimedia content on social media sites offers vital information. Reports of injured or deceased people, infrastructure destruction, and missing or found people are among the types of information exchanged. While several studies have demonstrated the importance of both text and picture content for disaster response, previous research has primarily concentrated on the text modality and not so much success with multi-modality. Latest research in multi-modal classification in disaster related tweets uses comparatively primitive models such as KIMCNN and VGG16. In this research work we have taken this further and utilized state-of-the-art models in both text and image classification to try and improve multi-modal classification of disaster related tweets. The research was conducted on two different classification tasks, first to detect if a tweet is informative or not, second to understand the response needed. The process of multimodal analysis is broken down by incorporating different methods of feature extraction from the textual data corpus and pre-processing the corresponding image corpus, then we use several classification models to train and predict the output and compare their performances while tweaking the parameters to improve the results. Models such as XLNet, BERT and RoBERTa in text classification and ResNet, ResNeXt and DenseNet in image classification were trained and analyzed. Results show that the proposed multimodal architecture outperforms models trained using a single modality (text or image alone). Also, it proves that the newer state-of-the-art models outperform the baseline models by a reasonable margin for both the classification tasks.

     

Influence of water quality on plankton in tropical ponds: A multivariate analysis approach

Plankton are highly sensitive to environmental changes, therefore being excellent water indicators. This study was conducted to classify water and sediment quality characteristics and different genera of phytoplankton and zooplankton in three ponds. The prominent water and sediment quality characteristics responsible for the occurrence of phytoplankton and zooplankton were also studied. The nutrient pollution factor is mainly responsible for the abundance of Cyanophyceae and for reduction in Rotifera, Cladocera, Copepoda and Ostracoda. The organic pollution factor is responsible for the abundance of Bacillariophyceae and Protozoa. The products of mineralization have more influence on the decreased Chlorophyceae. Thus, it is essential to control the disposal of pollutants into the study pond system.     

Case study on energy audit in HPCL,Mazgaon Dock Ltd,Mumbai

ABSTRACT

The paper comprises Energy Audit of Mechanical Equipment in HPCL (Hindustan Petroleum Corporation Limited), Mazgaon Dock, Mumbai. It represents the energy audit of counter-flow-type-induced draft cooling tower and other mechanical equipment. The technical data have been taken from Paharpur cooling tower (series 3800) HPCL, Mazgaon. Lube Plant 1 Cooling towers are generally heat-removal devices for industrial processes as well as for for chemical plants. The present review is aimed at study and research on the cooling tower for increasing the efficiency and power savings to make it more economical and efficient. Using boiler of high efficiency helps in reducing the cost which is an important factor in industries and to reduce the emissions. The direct efficiency method can be used but it does not focus on energy losses so the standard methods are used. But the modified Siegert’s equation is a very common equation for finding out the boiler efficiency.