Trapping of vibration energy into a set of resonators: Theory and application to aerospace structures

Cataloged from PDF version of article.This paper presents the theory of a novel mechanism of energy absorption and induced damping in structural systems and its application to aerospace industry. The underlying principles of the physical phenomena have been addressed in several earlier publications, which focused on prototypical systems of absorbers that consist of a set of single-degree-of-freedom resonators. This paper generalizes those theoretical developments to the case of a cluster of beams attached to a continuous primary structure, to develop predictive methods for the expected performance of this new type of absorber, with particular emphasis on its optimal design. An embodiment of the conceived device is illustrated for an aerospace structure, a satellite, with the purpose of reducing the vibration of the electronic components on board during lift-off. Experimental results illustrate the feasibility and the attractiveness of this new absorption technique. (C) 2011 Elsevier Ltd. All rights reserved

Measurement and Monitoring of Microwave Reflection and Transmission Properties of Cement-Based Specimens

The results of measurement and monitoring of reflection and transmission properties of cement-based specimens (blocks of mortar, concrete) during long time of their service lives, including hydration process, and different curing conditions at microwave frequencies (X-band) are presented. A simple and inexpensive measurement system that utilizes the nondestructive and contactless free space method is used. Dependencies of the reflection and transmission coefficients on water-to-cement ratio, preparing and curing conditions of the specimens are demonstrated. It is shown that the reflection coefficient is approximately stable after hydration process while the transmission coefficient changes during long time of the specimen\u27\u27s service life. The complex dielectric permittivity of the cement-based materials is calculated by a new method using only the amplitudes of the reflection and transmission coefficients. The expected applications of the results are discussed

Measurement and Monitoring of Microwave Reflection and Transmission Properties of Cement-Based Materials for Propagation Modeling

A non-destructive, contactless, free-space method is used for measuring and monitoring the properties of cement-based materials. We analyse the propagation factor, penetration depth and reflection and transmission coefficients of the plane wave interacting with the highly lossy specimen. Results are presented of the measurement and monitoring of the properties of cement-based materials during all stages of their lives and different curing conditions The expected applications of the results for propagation modelling are discussed

Measurement and Monitoring of Microwave Reflection and Transmission Properties of Cement-Based Specimens

The results of measurement and monitoring of reflection and transmission properties of cement-based specimens (blocks of mortar, concrete) obtained by using a simple and an inexpensive measurement system at microwave frequencies (X-band) are presented. Dependencies of the reflection and transmission coefficients on water-to-cement (w/c) ratio, preparing and curing conditions of the specimens are demonstrated. It is shown that the amplitudes of reflection and transmission coefficients, together with thickness of the specimens, determine the complex dielectric permittivity of the hardened cement-based specimens. The expected applications of the results for the determination of physical properties of cement-based materials are discussed. The causes and effects of measurement errors and uncertainties are also discussed

Making Tactile Textures with Predefined Affective Properties

A process for the design and manufacture of 3D tactile textures with predefined affective properties was developed. Twenty four tactile textures were manufactured. Texture measures from the domain of machine vision were used to characterize the digital representations of the tactile textures. To obtain affective ratings, the textures were touched, unseen, by 107 participants who scored them against natural, warm, elegant, rough, simple, and like, on a semantic differential scale. The texture measures were correlated with the participants' affective ratings using a novel feature subset evaluation method and a partial least squares genetic algorithm. Six measures were identified that are significantly correlated with human responses and are unlikely to have occurred by chance. Regression equations were used to select 48 new tactile textures that had been synthesized using mixing algorithms and which were likely to score highly against the six adjectives when touched by participants. The new textures were manufactured and rated by participants. It was found that the regression equations gave excellent predictive ability. The principal contribution of the work is the demonstration of a process, using machine vision methods and rapid prototyping, which can be used to make new tactile textures with predefined affective properties

Gambaran Pengetahuan Masyarakat Tentang Penyakit Malaria Di Kecamatan Silian Raya Kabupaten Minahasa Tenggara

: Malaria is a disease caused by the protozoa obligate intracellular species of Plasmodium genus. In Indonesia, malaria is a very complex problem of public health. This was a descriptive study, using questionnaires to the respondents. The study was conducted in Silian Raya (Minahasa Tenggara) during October 2014 until January 2015. There were 194 respondents. Sampling system was based on cluster random sampling in each village, then for sampling of each village we used simple random sampling. All respondents had heard about malaria disease (100%), and most respondents obtained that information from health counseling (65.5%). The knowledge that malaria was due to mosquito bites were found among 99.5% respondents, but most respondents did not know about the type of mosquitoes that caused malaria. The knowledge about the time that the mosquitoes transmitting malaria bit at night was found among 57.7% respondents. The knowledge about the breeding of malaria mosquito was found among 99.5% respondents; about signs and symptoms of malaria 99.5% respondents; and prevention of malaria 99.5% respondents

Model validation for a noninvasive arterial stenosis detection problem

Copyright @ 2013 American Institute of Mathematical SciencesA current thrust in medical research is the development of a non-invasive method for detection, localization, and characterization of an arterial stenosis (a blockage or partial blockage in an artery). A method has been proposed to detect shear waves in the chest cavity which have been generated by disturbances in the blood flow resulting from a stenosis. In order to develop this methodology further, we use both one-dimensional pressure and shear wave experimental data from novel acoustic phantoms to validate corresponding viscoelastic mathematical models, which were developed in a concept paper [8] and refined herein. We estimate model parameters which give a good fit (in a sense to be precisely defined) to the experimental data, and use asymptotic error theory to provide confidence intervals for parameter estimates. Finally, since a robust error model is necessary for accurate parameter estimates and confidence analysis, we include a comparison of absolute and relative models for measurement error.The National Institute of Allergy and Infectious Diseases, the Air Force Office of Scientific Research, the Deopartment of Education and the Engineering and Physical Sciences Research Council (EPSRC)

Thoracoscopic Repair of Congenital Diaphragmatic Hernia in Neonates: Lessons Learned

Abstract Purpose: We sought to characterize our recent experience with thoracoscopic congenital diaphragmatic hernia (CDH) repair and identify patient selection factors. Methods: We reviewed the medical records of full-term neonatal (<1 month of age) patients who underwent thoracoscopic CDH repair between 2004 and 2008 (n=15). We obtained data on prenatal diagnosis, characteristics of the CDH and repair, complications, and outcome. Results: All patients were stabilized preoperatively and underwent repair at an average of 5.7+/-1.3 days. Six patients were prenatally diagnosed, including the 5 inborn. Thirteen defects were left-sided. All were intubated shortly after birth and 2 required extracorporeal membrane oxygenation (ECMO). Twelve of 15 (80%) patients underwent successful thoracoscopic primary repair, including 1 of the patients who required ECMO prior to repair. Conversion to open repair occurred in 3 of 15 (20%) patients because of the need for patch closure or intraoperative instability. Among those converted to open, all had left-sided CDH defects and 3 had stomach herniation (of 5 such patients). Patients spent an average of 6.9+/-1.0 days on the ventilator following repair. The average time until full-enteral feeding was 16.7+/-2.25 days, and average length of hospital stay was 23.8+/-2.73 days. All patients survived to discharge, and average length of follow-up was 15.3+/-3.6 months. Conclusions: Thoracoscopic repair of CDH is a safe, effective strategy in patients who have undergone prior stabilization. Stomach herniation is associated with, but does not categorically predict, conversion to open repair. ECMO use prior to repair should not be an absolute contraindication to thoracoscopic repair.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78119/1/lap.2009.0129.pd

C8‐BTBT‐C8 Thin‐Film Transistors Based on Micro‐Contact Printed PEDOT:PSS/MWCNT Electrodes

Advances in organic materials manufacturing have enabled the creation of electronic devices using solution‐processing techniques by employing soluble materials with high conductivity grade. In this exploratory study, the use of micro‐contact for poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymer ink deposition as high‐quality structured electrodes for organic field‐effect transistors (OFETs) in top‐contact geometry is demonstrated. The optimized OFET's solution‐processed fabrication is a promising strategy to be realized in the simple, cost‐effective roll‐to‐roll manufacturing processes. The electrical performance of the fabricated devices is comparable to transistors with gold electrodes prepared via vacuum deposition, and even exceeding the values of the charge carriers’ mobilities and featuring lower contact resistance (Rc), due to lower charge‐carrier injection barrier for carbon‐based organic electrodes. An addition of multi‐walled carbon nanotubes to the PEDOT:PSS decreases Rc even further, changing the work function for better energy alignment with semiconductor materials

Emigration, remittances, and the subjective well-being of those staying behind

© 2018, The Author(s). We offer the first global perspective on the well-being consequences of emigration for those staying behind using several subjective well-being measures (evaluations of best possible life, positive affect, stress, and depression). Using the Gallup World Poll data for 114 countries during 2009–2011, we find that having family members abroad is associated with greater evaluative well-being and positive affect, and receiving remittances is linked with further increases in evaluative well-being, especially in poorer contexts—both across and within countries. We also document that having household members abroad is linked with increased stress and depression, which are not offset by remittances. The out-migration of family members appears less traumatic in countries where migration is more common, indicating that people in such contexts might be able to cope better with separation. Overall, subjective well-being measures, which reflect both material and non-material aspects of life, furnish additional insights and a well-rounded picture of the consequences of emigration on migrant family members staying behind relative to standard outcomes employed in the literature, such as the left-behind’s consumption, income, or labor market outcomes