Dynamic behavior of microcantilevers subjected to fluid-structure interaction using mode-summation method

ABSTRACT Dynamic behavior of microcantilevers subjected to fluid-structure interaction using Mode Summation method Pranav Ashtaputre Several Microsystems exhibit interaction of flexible structures such as beams, plates, membranes with fluid. Some of these systems are micropumps, flow sensors and micro valves. It is crucial to consider the effects of fluid parameters such as density, viscosity, velocity and pressure loading while designing these systems. The design of these systems demand a numerical model to understand the dynamic behavior of various elements involved in these systems. Microcantilever is an important structure which exhibits interaction with fluids in various microsystems. The present thesis focuses on the numerical modeling of dynamics of a microcantilever vibrating under the action of fluid loading. Natural frequencies and mode shapes of cantilever are obtained using characteristic orthogonal polynomials in the Rayleigh Ritz method. Numerical model is formed by solving Euler Bernoulli Equation of beam using mode summation method with normal modes of cantilever. The excitation frequency and fluid pressures are obtained from experimental results are explored for modeling and verification purposes. The results are obtained for the tip deflection of the beam. The results are validated with the results obtained in earlier experiments. The deflection amplitudes from the numerical model and those from experiment are found to be in agreement with each other. A parametric study is also presented with different sizes of microcantilever. The effect of different lengths and widths of microcantilever on the deflection amplitudes is presented. However, the effect of structural deformation due to the changes in fluid pressure is not considered. The model can be further extended to explore the dynamics of microplate used in micropumps with the help of precise fluid pressure data for a particular dynamic system and mode shapes obtained in free vibration analysis. The model provides the first step towards finding a solution to the problems involving fluid loading on microsystems

Cotton based bioactive wound dressing material with high absorbency and antibacterial activity

63-68Cotton gauze fabrics with improved absorbency through yarn twist optimization and antimicrobial property using nanosilver have been prepared. The absorbency, mass loss (%), dehydration rate, wicking rate, surface morphology, surface chemical nature and antibacterial activity of cotton gauze fabrics have been evaluated. The gauze fabric with low twisted yarn shows better absorbency and vertical wicking rate as compared to that with higher twisted yarn. The cotton gauze fabric with optimized twist multiplier (3.0 TM) is then treated with silver nitrate precursor to form in-situ nanosilver on the surface of cotton by applying elevated pressure and temperature. The surface morphology has been studied by SEM and chemical nature by FTIR. The in-situ technique produces an average nanosilver particle size of 120 ± 48 nm and shows 100% reduction for Klebsiella pneumoniae (Gram-negative bacterium) and 99.99% for Staphylococcus aureus (Gram-positive bacterium)

Cotton based bioactive wound dressing material with high absorbency and antibacterial activity

Cotton gauze fabrics with improved absorbency through yarn twist optimization and antimicrobial property using nanosilver have been prepared. The absorbency, mass loss (%), dehydration rate, wicking rate, surface morphology, surface chemical nature and antibacterial activity of cotton gauze fabrics have been evaluated. The gauze fabric with low twisted yarn shows better absorbency and vertical wicking rate as compared to that with higher twisted yarn. The cotton gauze fabric with optimized twist multiplier (3.0 TM) is then treated with silver nitrate precursor to form in-situ nanosilver on the surface of cotton by applying elevated pressure and temperature. The surface morphology has been studied by SEM and chemical nature by FTIR. The in-situ technique produces an average nanosilver particle size of 120 ± 48 nm and shows 100% reduction for Klebsiella pneumoniae (Gram-negative bacterium) and 99.99% for Staphylococcus aureus (Gram-positive bacterium

Characterization of the Exopolysaccharide Produced by Salipiger mucosus A3T, a Halophilic Species Belonging to the Alphaproteobacteria, Isolated on the Spanish Mediterranean Seaboard

We have studied the exopolysaccharide produced by the type strain of Salipiger mucosus, a species of halophilic, EPS-producing (exopolysaccharide-producing) bacterium belonging to the Alphaproteobacteria. The strain, isolated on the Mediterranean seaboard, produced a polysaccharide, mainly during its exponential growth phase but also to a lesser extent during the stationary phase. Culture parameters influenced bacterial growth and EPS production. Yield was always directly related to the quantity of biomass in the culture. The polymer is a heteropolysaccharide with a molecular mass of 250 kDa and its components are glucose (19.7%, w/w), mannose (34%, w/w), galactose (32.9%, w/w) and fucose (13.4%, w/w). Fucose and fucose-rich oligosaccharides have applications in the fields of medicine and cosmetics. The chemical or enzymatic hydrolysis of fucose-rich polysaccharides offers a new efficient way to process fucose. The exopolysaccharide in question produces a solution of very low viscosity that shows pseudoplastic behavior and emulsifying activity on several hydrophobic substrates. It also has a high capacity for binding cations and incorporating considerable quantities of sulfates, this latter feature being very unusual in bacterial polysaccharides

Intoxicating Messages: A Study on Memorable Messages and Binge Drinking

Binge drinking amongst college students is a concerning issue for parents and professionals who are trying to combat this maladaptive behavior. In 2018, 19.9 million people were projected to attend colleges in the U.S. (National Center for Education Statistics, n.d.) and nearly 38% of college students ages 18-22 binge drink (National Institute on Alcohol Abuse and Alcoholism [NIAAA], 2018). About 1,825 of them die from alcohol-related deaths each year (NIAAA, 2015). Despite years of national efforts to reduce binge drinking, it appears that little change has occurred. This may be due to the paucity of information and research on the communication practices people encounter in interpersonal and media contexts surrounding drinking. Some of these practices and ways information is communicated could be damaging and could be a component of why people choose to drink excessively. To date, no research has examined alcohol/drinking-related messages students recall and their perceptions of binge drinking. To fill the gap as to why college students’ binge drink, this research uses memorable messages and the health belief model as a guide to understand the message content that individuals remember of alcohol-related messages and how those messages are linked to binge drinking. The study surveyed 441 undergraduate students enrolled in communication courses at a large southwestern university during the Spring of 2019. Qualitative and quantitative data was collected in order to obtain the actual memorable messages that were recalled and the themes that emerged, as well as understanding the association between the memorable message and binge drinking. Results indicated that undergraduates were able to recall memorable messages about drinking, the messages mostly come from friends and mothers, and that the messages were about drinking responsibly and managing alcohol, promoting drinking, and warning messages about the dangers of drinking. Additionally, this study revealed that there was an association between pro-binge drinking messages and binge drinking, compared to no memorable message and recalling an anti-binge drinking message, and that binge drinking was mediated by benefits, barriers, and drinking-refusal self-efficacy

Boys Go, Girls Go Along: exploring gender and price differences regarding themes present on children’s graphic t-shirts

Purpose: Using gender schema theory, this study aims to explore how children’s graphic t-shirts from clothing retailers in the USA differed on gendered themes for graphic t-shirts targeting boys or girls, in addition to differences for shirts that were higher in cost. Design/methodology/approach: This content analysis of children’s t-shirts included 866 child-targeted shirts taken from the online retail portals from 11 clothing retailers in the USA. Shirts were coded for gendered themes on the front torso part of the shirt and included traditional boy themes (e.g. aggression, instrumentality) and girl themes (e.g. compassion, passivity). In addition, the retail prices for each shirt were recorded at the time of data collection. Findings: The results demonstrated that children’s graphic t-shirts starkly differentiate between femininity and masculinity based on their target. Boys’ shirts were significantly more likely to feature active themes, whereas girls’ shirts were more likely to focus on social belonging and interpersonal connection. Boys’ shirts were also more likely to display themes linked to dominance/aggression but not compassion. Girls’ shirts were more likely to tout both shyness and attention seeking. Finally, results generally showed that higher priced t-shirts were less likely to feature gender stereotypes than lower-priced t-shirts. Originality/value: To the best of the authors’ knowledge, this is the first known study that has looked at the marketing of children’s clothes in retail environments with a specific focus on gender and gender stereotyping.Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

A novel tissue engineering technique for regeneration of lost interdental papillary height

Open interdental spaces caused by papillary gingival recession are one of the most common problems faced in dentistry. Surgical and nonsurgical periodontal treatments for regeneration of lost papillary height have been reported with limited success. The present study reports effectiveness of autologous cultured fibroblast injections, a tissue engineering technique for papillary regeneration. A black triangle caused by Tarnow′s and Nordland′s class I papillary gingival loss was reported in maxillary anterior region of a young male patient. An autologous gingival biopsy was cultured in a biotechnology lab for the growth and expansion of fibroblasts. Cultured fibroblast suspension was injected into the receded papilla twice at an interval of 5 days. Follow-ups were recorded on the 6th day, 15 th day, at 1 month and at 2 months. Complete fill of black triangle was noted at the end of 2 months. No inflammatory or immune reactions were noted at the site of injection. Autologous cultured fibroblast injections are safe, efficacious, and an acceptable treatment option for the regeneration of lost papillary height

Enhanced field emission from ZnO nanoneedles on chemical vapour deposited diamond films

ZnO nanoneedles were coated on hot filament chemical vapour deposited diamond thin films to enhance the field emission properties of ZnO nanoneedles. The virgin diamond films and ZnO nanoneedles on diamond films were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The field emission studies reveal that the ZnO nanoneedles coated on diamond film exhibit better emission characteristics, with minimum threshold field (required to draw a current density ~ 1 μA/cm2) as compared to ZnO needles on silicon and virgin diamond films. The better emission characteristic of ZnO nanoneedles on diamond film is attributed to the high field-enhancement factor resulting due to the combined effect of the ZnO nanoneedles and diamond film

Scenario of Wilt Incidence of Chickpea in Major Chickpea Growing Regions of Northern Karnataka, India

The chickpea (Cicer arietinum L.) is one of the important pulse crops grown in India. Chickpea wilt complex is one of the most devastating crop diseases in northern Karnataka. Because of abundant inoculum in the soil and suitable environment circumstances, infected plants die, resulting in full loss of yield. A random roaming study was done in important chickpea farming districts of northern Karnataka, namely Dharwad, Belagavi, Haveri, Gadag, Bagalkot, Kalaburgi, and Vijayapur, during Rabi 2021-22 and 2022-22, to establish disease incidence and its in severity in different places. The survey results demonstrated a link between three pathogens: Fusarium oxysporum f. sp. ciceri, Rhizoctonia bataticola, and Sclerotia rolfsii. Dharwad district has the highest illness incidence (30.20%), followed by Kalburgi district.with 29.85 per cent