6,778 research outputs found

    Investigation of electrical properties for cantilever-based piezoelectric energy harvester

    Get PDF
    In the present era, the renewable sources of energy, e.g., piezoelectric materials are in great demand. They play a vital role in the field of micro-electromechanical systems, e.g., sensors and actuators. The cantilever-based piezoelectric energy harvesters are very popular because of their high performance and utilization. In this research-work, an energy harvester model based on a cantilever beam with bimorph PZT-5A, having a substrate layer of structural steel, was presented. The proposed energy scavenging system, designed in COMSOL Multiphysics, was applied to analyze the electrical output as a function of excitation frequencies, load resistances and accelerations. Analytical modeling was employed to measure the output voltage and power under pre-defined conditions of acceleration and load resistance. Experimentation was also performed to determine the relationship between independent and output parameters. Energy harvester is capable of producing the maximum power of 1.16 mW at a resonant frequency of 71 Hz under 1g acceleration, having load resistance of 12 k Omega. It was observed that acceleration and output power are directly proportional to each other. Moreover, the investigation conveys that the experimental results are in good agreement with the numerical results. The maximum error obtained between the experimental and numerical investigation was found to equal 4.3%

    Antimicrobial and phytotoxic screening of various fractions of Sonchus asper

    Get PDF
    Sonchus asper is used in the treatment of many diseases ethnopharmacologically in Pakistan. In the present manuscript we demonstrate the antimicrobial and phytotoxic effects of various fractions of S.asper. Six (6) different bacteria (Escherichia coli, Bacillus subtilis, Micrococcus luteus, klebsiella pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa) are used in the screening of extract as well as 4 strains of fungi are characterized. Raddish root inhibition assay was used for phytotoxic screening. Methanolic fraction of S. asper showed best activities in all of assays, in inhibition of microbes and phytotoxic activities. The potency of these activities is due to the presence of bioactive flavonoids, saponins and phenolic compounds

    Phytotoxic characterization of various fractions of Launaea procumbens

    Get PDF
    Allelopathic screening of various fractions of Launaea procumbens, collected from Wah Cantt (Punjab) Pakistan, was conceded to identify potent allelopathic fraction for future phytochemical analyses. For this purpose, radish root inhibition method was used to test allelopathic potential. Two different concentrations of 100 ppm and 1000 ppm of Launaea procumbens were used in this study. Methanolic and ethyl acetate fraction potently inhibited root and radical growth; comparative to other fractions, it might be due to the presence of bioactive allelochemicals. Based on this screening, both of these fractions were recommended for future bioassay guided isolation of allelochemicals.Key words: Launaea procumbens, radish seeds, root inhibition, Launaea procumbens methanolic fraction

    A molecular phylogeny of selected species of genus Prunus L. (Rosaceae) from Pakistan using the internal transcribed spacer (ITS) spacer DNA

    Get PDF
    Prunus is found in all four provinces of Pakistan, that is, Punjab, NWFP, Sindh and Baluchistan including Azad Kashmir region. Studies on the family Rosaceae is scanty in the Flora of Pakistan and there is a lot of taxonomic work yet to be done, for the proper classification and placement of different genera under different sub-families. In the present study, the genus Prunus was studied in detail to find out the phylogenetic relationship among the 23 species of Prunus, selected from different regions of Pakistan and GenBank using maximum parsimony analysis of sequence polymorphism in nuclear ITS-9 and ITS-6 spacer DNA. The results for the internal transcribed spacer (ITS)- 9 and ITS- 6 primers confirm the work done by early phylogenetists with additions of new species from Pakistan including Prunus bokhariensis, Prunus dulcis (Mill.) D.A. Webb. (Syn. Prunus amygdalus) and Prunus cornuta (Wall. ex. Royle) Steudel. These are indigenous to Pakistan. In the ITS strict consensus results for example, the clade consisting of Laurocerasus, Padus and Cerasus subgenera are sister to the rest of the clades in the phylogenetic tree.Key words: Phylogeny, Prunus, Pakistan, molecular phylogeny, nuclear primers

    Production of bioethanol through enzymatic hydrolysis of potato

    Get PDF
    Due to gradual decrease in petroleum resources and impacts of these wastes on the environment, there is a need to utilize the wastes of potatoes to get wealth out of wastes and clean the environment. In this study, potato wastes were investigated as source of bioethanol. 100 g potato powder was mixed with 1 L distilled water in two separate beakers to form potato slurry. Bioethanol production was investigated using effect of pH, temperature and mixture of digesting enzymes after scarification and fermentation. The results show that significant (p<0.05) bioethanol was produced at 35¬įC and at pH 5.5. This investigation also reveals that mixture of enzymes significantly enhanced (p<0.05) bioethanol production compared to non treated mixture. Maximum bioethanol productions were due to the presence of sugar in potatoes.Key words: Bioethanol, potato, ph, temperature, liquefaction

    Estimation of Para Red Dye in Chilli Powder and Tomato Sauces by a Simple Spectrophotmetric Method followed by Thin layer Chromatography

    Get PDF
    A number of grinded chilli powder samples and tomato sauce samples were collected from various localities of Karachi city. All the samples were estimated for the presence of para red which is an azo dye and more specifically belongs from the group of sudan dyes. According to the regulation of various governmental agencies its use in food is strictly prohibited because of its ability to form carcinogenic compounds. Although there were a number of sophisticated chromatographic methods for the estimation of this dye but we developed here a simple, convenient, expeditious spectrophotometric method followed by thin layer chromatography technique and compared the results by single point and multiple point external standard methods. On the basis of these results we also specify the localities of Karachi city where the contamination is more prominent. © JASE

    The Use of Software Design Patterns to Teach Secure Software Design: An Integrated Approach

    Get PDF
    Part 2: Software Security EducationInternational audienceDuring software development, security is often dealt with as an add-on. This means that security considerations are not necessarily seen as an integral part of the overall solution and might even be left out of a design. For many security problems, the approach towards secure development has recurring elements. Software design patterns are often used to address a commonly occurring problem through a ‚Äúgeneric‚ÄĚ approach towards this problem. The design pattern provides a conceptual model of a best-practices solution, which in turn is used by developers to create a concrete implementation for their specific problem. Most software design patterns do not include security best-practices as part of the generic solution towards the commonly occurring problem. This paper proposes an extension to the widely used MVC pattern that includes current security principles in order to teach secure software design in an integrated fashion

    Detection of non-melanoma skin cancer by in vivo fluorescence imaging with fluorocoxib A.

    Get PDF
    Non-melanoma skin cancer (NMSC) is the most common form of cancer in the US and its incidence is increasing. The current standard of care is visual inspection by physicians and/or dermatologists, followed by skin biopsy and pathologic confirmation. We have investigated the use of in vivo fluorescence imaging using fluorocoxib A as a molecular probe for early detection and assessment of skin tumors in mouse models of NMSC. Fluorocoxib A targets the cyclooxygenase-2 (COX-2) enzyme that is preferentially expressed by inflamed and tumor tissue, and therefore has potential to be an effective broadly active molecular biomarker for cancer detection. We tested the sensitivity of fluorocoxib A in a BCC allograft SCID hairless mouse model using a wide-field fluorescence imaging system. Subcutaneous allografts comprised of 1000 BCC cells were detectable above background. These BCC allograft mice were imaged over time and a linear correlation (R(2) = 0.8) between tumor volume and fluorocoxib A signal levels was observed. We also tested fluorocoxib A in a genetically engineered spontaneous BCC mouse model (Ptch1(+/-) K14-Cre-ER2 p53(fl/fl)), where sequential imaging of the same animals over time demonstrated that early, microscopic lesions (100 őľm size) developed into visible macroscopic tumor masses over 11 to 17 days. Overall, for macroscopic tumors, the sensitivity was 88% and the specificity was 100%. For microscopic tumors, the sensitivity was 85% and specificity was 56%. These results demonstrate the potential of fluorocoxib A as an in vivo imaging agent for early detection, margin delineation and guided biopsies of NMSCs

    Multi-response optimization of face milling performance considering tool path strategies in machining of Al-2024

    Get PDF
    It is hypothesized that the orientation of tool maneuvering in the milling process defines the quality of machining. In that respect, here, the influence of different path strategies of the tool in face milling is investigated, and subsequently, the best strategy is identified following systematic optimization. The surface roughness, material removal rate and cutting time are considered as key responses, whereas the cutting speed, feed rate and depth of cut were considered as inputs (quantitative factors) beside the tool path strategy (qualitative factor) for the material Al 2024 with a torus end mill. The experimental plan, i.e., 27 runs were determined by using the Taguchi design approach. In addition, the analysis of variance is conducted to statistically identify the effects of parameters. The optimal values of process parameters have been evaluated based on Taguchi-grey relational analysis, and the reliability of this analysis has been verified with the confirmation test. It was found that the tool path strategy has a significant influence on the end outcomes of face milling. As such, the surface topography respective to different cutter path strategies and the optimal cutting strategy is discussed in detail

    The disproportionate case‚Äďfatality ratio of COVID-19 between countries with the highest vaccination rates and the rest of the world

    Get PDF
    Objectives: The global reported cumulative case‚Äďfatality ratios (rCFRs) and excess mortality rates of the 20 countries with the highest coronavirus disease 2019 (COVID-19) vaccination rates, the rest of the world and Sub-Saharan Africa (SSA) were compared before and after the commencement of vaccination programmes. Methods: A time series model was used to understand the trend of rCFR over time, and a generalized linear mixed model was used to understand the effect of vaccination on rCFR. Results: By 31 December 2022, an average of 260.3 doses of COVID-19 vaccine per 100 population had been administered in the top 20 vaccinated countries, compared with 152.1 doses in the rest of the world and 51.2 doses in SSA. The mean rCFR of COVID-19 had decreased by 69.0% in the top 20 vaccinated countries, 26.5% in the rest of the world and 7.6% in SSA. Excess mortality had decreased by 48.7% in the top 20 vaccinated countries, compared with 62.5% in the rest of the world and 60.7% in SSA. In a generalized linear mixed model, the reported number of vaccine doses administered (/100 population) (odds ratio 0.64) was associated with a steeper reduction in COVID-19 rCFR. Conclusions: Vaccine equity and faster roll-out across the world is critically important in reducing COVID-19 transmission and CFR
    • ‚Ķ
    corecore