Performance evaluation of a piezoelectric energy harvester based on flag-flutter

In the last few decades, piezoelectric (PZT) materials have played a vital role in the aerospace industry because of their energy harvesting capability. PZT energy harvesters (PEH) absorb the energy from an operational environment and can transform it into useful energy to drive nano/micro-electronic components. In this research work, a PEH based on the flag-flutter mechanism is presented. This mechanism is based on fluid-structure interaction (FSI). The flag is subjected to the axial airflow in the subsonic wind tunnel. The performance evaluation of the harvester and aeroelastic analysis is investigated numerically and experimentally. A novel solution is presented to extract energy from Limit Cycle Oscillations (LCOs) phenomenon by means of PZT transduction. The PZT patch absorbs the flow-induced structural vibrations and transforms it into electrical energy. Furthermore, the optimal resistance and length of the flag is predicted to maximize the energy harvesting. Different configurations of flag i.e., with Aluminium (Al) patch and PZT patch for flutter mode vibration mode are studied numerically and experimentally. The bifurcation diagram is constructed for the experimental campaign for the flutter instability of a cantilevered flag in subsonic wind-tunnel. Moreover, the flutter boundary conditions are analysed for reduced critical velocity and frequency. The designed PZT energy harvester via flag-flutter mechanism is suitable for energy harvesting in aerospace engineering applications to drive wireless sensors. The maximum output power that can be generated from the designed harvester is 6.72 mW and the optimal resistance is predicted to be 0.33 MΩ

Crystallographic and NMR Investigation of Ergometrine and Methylergometrine, Two Alkaloids from Claviceps purpurea

Ergometrine and methylergometrine are two alkaloids that are used as maleate salts for the prevention and control of postpartum hemorrhage. Although the two molecules have been known for a long time, few and discordant crystallographic and NMR spectroscopic data are available in the literature. With the aim of providing more conclusive data, we performed a careful NMR study for the complete assignment of the 1H, 13C, and 15N NMR signals of ergometrine, methylergometrine, and their maleate salts. This information allowed for a better definition of their conformational equilibria. In addition, the stereochemistry and the intermolecular interactions in the solid state of the two maleate salts were deeply investigated by means of single-crystal X-ray diffraction, showing the capability of these derivatives to act as both hydrogen-bond donors and acceptors, and evidencing a correlation between the number of intermolecular interactions and their different solubility

(S)-Pramipexole and Its Enantiomer, Dexpramipexole : a New Chemoenzymatic Synthesis and Crystallographic Investigation of Key Enantiomeric Intermediates

A new chemoenzymatic method has been developed for the synthesis of (S)- and (R)-N-(6-hydroxy-4,5,6,7-tetrahydrobenzo[d]thiazol-2-yl) acetamide, two key synthons for the preparation of (S)-pramipexole, an anti-Parkinson drug, and its enantiomer dexpramipexole, which is currently under investigation for the treatment of eosinophil-associated disorders. These two building blocks have been obtained in good yields and high enantiomeric excess (30% and >98% ee for the R-enantiomer, and 31% and >99% ee for the S- one) through a careful optimization of the reaction conditions, starting from the corresponding racemic mixture and using two consecutive irreversible transesterifications, catalyzed by Candida antarctica lipase type A. Single crystal X-ray analysis has been carried out to unambiguously define the stereochemistry of the two enantiomers, and to explore in depth their three-dimensional features

Reliability and validity of opiate use self-report in a population at high risk for esophageal cancer in Golestan, Iran

Objective: To assess the reliability and validity of self-reported opium use in a rural Iranian population at high risk for esophageal cancer in preparation for a large cohort study. Method: 1,057 subjects ages 33 to 84 years were recruited from Gonbad city and three surrounding villages in Golestan province of Iran and completed a questionnaire and provided biological samples. The history and duration of using opium, smoking tobacco, chewing nass, and drinking alcohol were measured by questionnaire in the entire cohort. A subgroup of 130 people was reinterviewed after 2 months to assess reliability. Validity of the opium question was assessed by comparing the questionnaire responses with the presence of codeine and morphine in the urine of 150 selected subjects. Results: Self-reported opiate use is reliable and valid in this population. The reliability of ever opium use and duration of opium use had κ′s of 0.96 and 0.74, respectively. The validity of self-reported opium use was also high. Using urine codeine or morphine as the gold standard for use of opium, self-report had a sensitivity of 0.93 and a specificity of 0.89. Conclusions: The self-reported use of opium can provide a reliable and valid measurement in this population and will be useful for studying associations between opium use and occurrence of esophageal cancer and other diseases

Alleviating the new user problem in collaborative filtering by exploiting personality information

The final publication is available at Springer via http://dx.doi.org/10.1007/s11257-016-9172-zThe new user problem in recommender systems is still challenging, and there is not yet a unique solution that can be applied in any domain or situation. In this paper we analyze viable solutions to the new user problem in collaborative filtering (CF) that are based on the exploitation of user personality information: (a) personality-based CF, which directly improves the recommendation prediction model by incorporating user personality information, (b) personality-based active learning, which utilizes personality information for identifying additional useful preference data in the target recommendation domain to be elicited from the user, and (c) personality-based cross-domain recommendation, which exploits personality information to better use user preference data from auxiliary domains which can be used to compensate the lack of user preference data in the target domain. We benchmark the effectiveness of these methods on large datasets that span several domains, namely movies, music and books. Our results show that personality-aware methods achieve performance improvements that range from 6 to 94 % for users completely new to the system, while increasing the novelty of the recommended items by 3-40 % with respect to the non-personalized popularity baseline. We also discuss the limitations of our approach and the situations in which the proposed methods can be better applied, hence providing guidelines for researchers and practitioners in the field.This work was supported by the Spanish Ministry of Economy and Competitiveness (TIN2013-47090-C3). We thank Michal Kosinski and David Stillwell for their attention regarding the dataset

Design and performance analysis of hybrid solar powered geyser in Islamabad, Pakistan

As a consequence of energy crisis and pollution around the globe, many countries are shifting towards the renewable energy resources which are environmental friendly too i.e., solar energy. The aim of this research work is to design a solar powered geyser that can be used for domestic as well as for industrial purposes. The analytical model is constructed to understand the behavior of water temperature with respect to time and to the energy that can be generated from solar panel with and without glass glazing. The extensive experimentation was carried out at self designed test rig in Islamabad, Pakistan for six months i.e., Aug 2017 - Jan 2018. The response of the power output to the time in specific month and its efficiency is predicted and optimized. Moreover, electrical backup was integrated in closed loop feedback circuit to achieve maximum efficiency even in dark cloudy weather or a sunny day. Moreover, it is calculated that how much external power is required by the system in order to perform the task at different time intervals of the day. Analytical results were in good agreement with experimental results, with error of 9%

Validity and reliability of a new food frequency questionnaire compared to 24h recalls and biochemical measurements: Pilot phase of Golestan cohort study of esophageal cancer

Background: A pilot study was carried out to evaluate validity and reproducibility of a food frequency questionnaire (FFQ), which was designed to be used in a prospective cohort study in a population at high risk for esophageal cancer in northern Iran. Methods: The FFQ was administered four times to 131 subjects, aged 35-65 years, of both sexes. Twelve 24-h dietary recalls for two consecutive days were administered monthly during 1 year and used as a reference method. The excretion of nitrogen was measured on four 24-h urine samples, and plasma levels of β-carotene, retinol, vitamin C and α-tocopherol was measured from two time points. Relative validity of FFQ and 24-h diet recall was assessed by comparing nutrient intake derived from both methods with the urinary nitrogen and plasma levels of β-carotene, retinol, vitamin C and α-tocopherol. Results: Correlation coefficients comparing energy and nutrients intake based on the mean of the four FFQ and the mean of twelve 24-h diet recalls were 0.75 for total energy, 0.75 for carbohydrates, 0.76 for proteins and 0.65 for fat. Correlation coefficients between the FFQ-based intake and serum levels of β-carotene, retinol, vitamin C and vitamin E/α-tocopherol were 0.37, 0.32, 0.35 and 0.06, respectively. Correlation coefficients between urinary nitrogen and FFQ-based protein intake ranged from 0.23 to 0.35. Intraclass correlation coefficients used to measure reproducibility of FFQ ranged from 0.66 to 0.89. Conclusion: We found that the FFQ provides valid and reliable measurements of habitual intake for energy and most of the nutrients studied. © 2006 Nature Publishing Group. All rights reserved