303 research outputs found
Social stewardship can help managers identify novel solutions amidst the COVID-19 crisis
While agency theory suggests that monetary rewards are a primary source of motivation for managers, stewardship theory suggests that in addition to monetary rewards, managers are motivated by higher order needs such as achievement, recognition from peers, and efforts towards enhancing the organisation as a collective. Niranjan Janardhanan writes that a stewardship-based culture encourages managers to understand the needs of stakeholders and enables them to identify novel solutions to thrive in turbulent times
Exploration of Deep Learning Models for Video Based Multiple Human Activity Recognition
Human Activity Recognition (HAR) with Deep Learning is a challenging and a highly demanding classification task. Complexity of the activity detection and the number of subjects are the main issues. Data mining approaches improved decision-making performance. This work presents one such model for Human activity recognition for multiple subjects carrying out multiple activities. Involving real time datasets, the work developed a rapid algorithm for minimizing the problems of neural networks classifier. An optimal feature extraction happens and develops a multi-modal classification technique and predicts solutions with better accuracy when compared to other traditional methods. This paper discussing on HAR prediction in four phases namely (i) Depthwise Separable Convolution with BiLSTM (DSC-BLSTM); (ii) Enhanced Bidirectional Grated Recurrent Unit with Long Short Term Memory (BGRU-LSTM); (iii) Enhanced TimeSformer Model with Multi-Layer Perceptron Neural Networks classification and (iv) Filtering Single Activity Recognition are described.In comparison to previous efforts like the DSC-BLSTM and BGRU-LSTM classifications, the experimental result of the ETMLP classification attained 98.90%, which was more efficient. The end outcome revealed that the new model performed better in terms of accuracy than the other models
Sulfur Poisoning of SOFCs: A Model Based Explanation of Polarization Dependent Extent of Poisoning
Several experimental studies have shown that, 1) the extent of the poisoning effect due to trace amounts of sulfur compounds in the fuel is lower if a SOFC is operated at a higher current density, and 2) the performance drop due to sulfur poisoning is much lower for Ni-GDC or Ni-ScSZ anodes when compared to Ni-YSZ anodes. This work presents a first principles numerical model that simulates experimental studies of sulfur poisoning on SOFC button cells. The exchange current densities for the electrodes are determined using sulfur-free polarization data for cells fueled by humidified mixtures of H2 and N2. A detailed surface reaction model that predicts the fractional coverage of all adsorbed species at the three phase interface is coupled to the SOFC model and the sulfur coverage is used to alter the anode exchange current density. The resulting model predictions match experimental observations during both galvanostatic and potentiostatic operation. Our analysis shows that the observed lower performance drop at higher current density is due to the non-linear nature of the electrochemical rate equations, and that the lower impact of sulfur poisoning on Ni-GDC and Ni-ScSZ anodes (compared to Ni-YSZ anodes) is due to their higher electrochemical activity
Numerical study of on-board fuel reforming in a catalytic plate reactor for solid-oxide fuel cells
A pseudo-transient numerical model is used for the simulation of a multi-functional catalytic plate reactor (CPR). The work mainly addresses the problems associated with on-board reforming for solid-oxide fuel cells. Heat management is achieved by indirectly coupling partial oxidation with reforming. Water management is achieved by partially recycling the anode stream from a solid-oxide fuel cell. The model uses detailed heterogeneous chemistry for reforming and oxidation reactions occurring on the catalyst beds
Deactivation and regeneration of Ni catalyst during steam reforming of model biogas: An experimental investigation
his paper presents detailed study of biogas reforming. Model biogas with different levels of H2S is subjected to reforming reaction over supported Ni catalyst in a fixed bed reactor at 700 °C and 800 °C. In order to understand the poisoning effects of H2S the reactions have been initially carried out without H2S in the feed stream. Three different H2S concentrations (20, 50 and 100 ppm) have been considered in the study. The H2O to CH4 ratio is maintained in such as way that CO2 also participates in the reforming reaction. After performing the poisoning studies, regeneration of the catalyst has been studied using three different techniques i) removal of H2S from the feed stream ii) temperature enhancement and iii) steam treatment. Poisoning at low temperature is not recoverable just by removal of H 2S from the feed stream. However, poisoning at high temperature is easily reversed just by removal of H2S from the feed stream. Unlike some previous reports by Li et al. (2010) and Rostrup-nielsen (1971) [1,2], catalyst regeneration is achieved in shorter time frames for all the regeneration techniques attempte
Phytochemical and Pharmacological studies on Cyathula Prostrata (Linn) Blume and Heliotropium Indicum (Linn).
Phytochemical and Pharmacological studies on Cyathula Prostrata (Linn) Blume and Heliotropium Indicum (Linn)
Cyathula prostata L. Blume is much branched slender prostrate or decumbent herbaceous perennial plant and Heliotropium indicum is succulent foetidy perennial
herb with densely hirsute ascending branches. The two plants were collected from Kottakal area, Kerala state and aunthenticated. The two plants were undertaken for
pharmacognostical standards such as Macroscopical, Organoleptic characters, and Physicochemical parameters like Total ash, acid insoluble ash, water soluble ash and
sulphated ash values were also determined.
The phytochemical studies of the plant extracts showed the presence of terepenoids, flavonols, phenols, and tannins in both the plants. So, the total phenolic content and flvonoidal content was Cyathula prostata and Heliotropium indicum were estimated respectively. Whereas the estimation of lupeol in Heliotropium indicum was carried out by using HPTLC.
The hydroethanolic extracts of both plants were found to be effective on experimental and drug induced ulcer models such as Modified pylorus ligated (Shay) rat model, Aspirin plus Modified pylorus ligated (Shay) rat model, Acetic induced
chronic ulcer model and Cysteamine induced duodenal ulcer model. The effect of whole plant extracts of Cyathula prostata and Heliotropium indicum on offensive and defensive factors of gastric content was studied on Modified pylorus ligated (Shay) rat model and drug induced ulcer model.
The study revealed that 200 mg/kg of hydroethanolic extracts of CP and HI regressed ulcer condition significantly. Whereas 400 mg/kg of both plant extracts effectively reduced the ulcers when compared to 200 mg/kg, showing the dose dependent activity.
The herbal extracts might control the ulcer formation by decreasing the secretion, drug induced damage and also by psychological stress. The herbal extracts were found to be more effective in controlling the ulcer in both the acute and chronic models. Further, cysteamine induced duodenal ulcer study indicated that the extracts possess anti ulcer activity against duodenal ulcers in dose dependent manner.
Hence it can be stated that herbal extracts may be beneficial in preventing the stress (including psychological or environmental stress), drug induced ulcers and also
act as anti secretary which may be attributed to the presence of phytoconstitiuents in plants. Reduction of gastric emptying time, Synthesis of mucosa, Inhibition of hypersecretion of gastric acid are the possible mechanisms through which the herbal extracts are possessing anti-ulcer activity.
Even though the present study revealed the activity of herbal extracts and the mechanism of action, the future studies are needed to be carried out to isolate and screen the phytoprinciples responsible for the anti-ulcer and mucoprotective activity and to correlate them with the mechanism of action. For further understanding of mechanism, the other models of ulcer induction such as ethanol induced gastric ulcers can also be carried out. Works in this direction are in progress, in the institution
A detailed kinetic model for biogas steam reforming on Ni and catalyst deactivation due to sulfur poisoning
This paper deals with the development and validation of a detailed kinetic model for steam reforming of biogas with and without H2S. The model has 68 reactions among 8 gasphase species and 18 surface adsorbed species including the catalytic surface. The activation energies for various reactions are calculated based on unity bond index-quadratic exponential potential (UBI-QEP) method. The whole mechanism is made thermodynamically consistent by using a previously published algorithm. Sensitivity analysis is carried out to understand the influence of reaction parameters on surface coverage of sulfur. The parameters describing sticking and desorption reactions of H2S are the most sensitive ones for the formation of adsorbed sulfur. The mechanism is validated in the temperature range of 873-1200 K for biogas free from H 2S and 973-1173 K for biogas containing 20-108 ppm H2S. The model predicts that during the initial stages of poisoning sulfur coverages are high near the reactor inlet; however, as the reaction proceeds further sulfur coverages increase towards the reactor exit. In the absence of sulfur, CO and elemental hydrogen are the dominant surface adsorbed species. High temperature operation can significantly mitigate sulfur adsorption and hence the saturation sulfur coverages are lower compared to low temperature operation. Low temperature operation can lead to full deactivation of the catalyst. The model predicts saturation coverages that are comparable to experimental observatio
MEDICINAL MUSHROOM BIOACTIVES: POTENTIAL SOURCES FOR ANTI-CANCER DRUG DEVELOPMENT
Mushrooms represent a major yet largely untapped source of therapeutically useful bioactive compounds. Despite mushrooms were in use since antiquity in traditional folk medicine attempts to isolate their bioactive components and to elucidate their medicinal properties have started only recently. Many pharmaceutical substances with unique properties were recently extracted from mushrooms and made their way all over the world. A number of medicinal mushrooms have been identified to possess anticancer effects recently. Some of the well-known examples are Lentinan from Lentinus edodes, Krestin from Trametes versicolor, Ganopoly from Ganoderma lucidum and Schizophyllan from Schizophyllum commune. We investigated the anticancer activities of a number of medicinal mushrooms in our laboratory. Some of the recent scientific evdences on the anticancer activities of Ganoderma lucidum, Phellinus rimosus, and Fomitopsis pinicola are discussed in this short review
Physiology and Biochemistry of a Lignin-Degrading Bacterium Erwinia Sp. Cu 3614.
Previous researchers have reported the isolation of a diphenylether cleaving organism, Erwinia sp., using an enrichment medium containing lignin. A copper and dinitrophenol resistant mutant of this organism, Erwinia sp. Cu3614, has also been reported. To assess the effect of copper on the growth and biochemistry of this organism, continuous cultivation was used employing an apparently optimized medium containing ethanol as carbon source. Upon increasing the concentration of copper sulfate in the medium from 5 g/ml to 10 g/ml increases in maximum specific growth rate and growth yield were seen. Also decrease in the values for doubling time and the coefficient for maintenance energy were seen. At higher levels of copper sulfate a non competitive inhibition of growth was seen as indicated by the values calculated for substrate affinity constant, and inhibition constant. To assess this organism\u27s ligninolytic ability, an assay for residual lignin was developed. The assay measured a reaction between diazotized sulfanilic acid and lignin in alkaline solution by spectrophotometric monitoring of the resulting adduct. Use of this technique indicated that Erwinia sp. Cu3614 could degrade up to 80% of lignin in batch cultures. Further evidence about the ligninolytic ability of this organism was provided by examination of electron micrographs of lignocellulosic substrates incubated with cell suspensions. An assay for monitoring diphenylether cleaving abilities was also developed using resazurin, a redox dye. In vivo assays with cells obtained from continuous culture studies indicated a linear relationship between the rates of reaction with resazurin and the amount of copper associated with cells. In vitro assays, employing cell free extracts and resazurin, were used to obtain a fraction enriched in diphenylether cleaving activity by a heat treatment procedure. This fraction could cleave methoxy groups from an arylether containing molecule, vanillin, to produce vanillyl alcohol and triphenylphosphate. Degradation of lignin in a continuous culture was also demonstrated
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