Properties of Nanogenerator Materials for Energy-Harvesting Application

Advancements in nanotechnology and materials science have led to the development of a variety of nanogenerator materials with improved properties, making energy harvesting technologies increasingly viable for various applications, such as powering wearable devices, remote sensors, and even small electronic gadgets in the future. The evolution of hybrid materials consisting of polymers and nanoparticles as efficient energy harvesters and energy storage devices is in high demand nowadays. Most investigations on organic ferroelectric P(VDF-TrFE) as a polymer host of polymer nanocomposite devices were primally focused on the β phase due to its excellent electrical properties for various application purposes. Nanofiller is also introduced into the polymer host to produce a polymer nanocomposite with enhanced properties. A brief description of various physical quantities related to ferroelectric, dielectric, pyroelectric effects and Thermally Stimulated Current (TSC) for energy harvesting applications in nanogenerator materials is presented. This article explores the different materials and uses of various nanogenerators. It explains the basics of the pyroelectric effect and the structure of pyroelectric nanogenerators (PNGs), as well as recent advancements in micro/nanoscale devices. Additionally, it discusses how the performance of ferroelectric, dielectric, pyroelectric, and TSC are impacted by the annealing treatment of P(VDF-TrFE) polymer

Lupus Anticoagulant in Nigerian Children With Homozygous Sickle Cell Disease

Background: Lupus anticoagulant (LA) is an antiphospholipid antibody (APLA), which recognise combinations of phospholipids or phospholipid -binding proteins or both and interfere with coagulation reactions dependent on protein phospholipid complexes in vitro. LA has paradoxically been associated with thrombosis and a myriad of clinical conditions such as cerebrovascular accidents (CVA). APLA have been described in adult homozygous sickle cell disease (SCD) patients and adults with \u3b2- thalassaemia. Our objective was to determine the presence or otherwise of LA in children with homozygous SCD and to see if they were more prone to developing LA compared to normal HbAA controls. Method: A total of 57 children with homozygous SCD between the ages 1-15 years were prospectively screened for the presence of LA using the kaolin clotting time (KCT), while 52 healthy HbAA children served as controls. KCT was performed in duplicates on all 109 subjects. Kaolin clotting time ratio was calculated to determine the presence of LA. A ratio greater than or equal to 1.2 was taken to signify the presence of LA. Results: One (1.8%) child with homozygous SCD had prolonged KCT, and this was not corrected by normal plasma, the KCT ratio was greater than 1.2, signifying the presence of LA. None of the control subjects had LA (p >0.05). Conclusion: One (1.8%) child in this study had LA; this value was not statistically significant when compared with HbAA controls. In spite of the fact that secondary LA is more common in females, the only patient with LA in our study was male and had no prior history of CVA or thrombosis.Fond : L'anticoagulant de lupus (AL) est un anticorps antiphospholipide (AAPL), qui identifie les combinaisons des phospholipides ou du phospholipide prot\ue9ines liantes ou toutes les deux et qui interf\ue8re avec des r\ue9actions de coagulation qui d\ue9pendent sur les complexes phospholipide de prot\ue9ine en vitro. L'AL a \ue9t\ue9 paradoxalement associ\ue9e \ue0 la thrombose et \ue0 une myriade de conditions cliniques tels que les accidents c\ue9r\ue9brovasculaires (ACV). AAPL ont \ue9t\ue9 d\ue9crits dans des malades adultes de dr\ue9panocytose homozygote et adultes de dr\ue9panocytose homozygote et des adultes avec la thalass\ue9mie de b. Notre objectif \ue9tait de d\ue9terminer la pr\ue9sence ou autrement d'AL chez les enfants avec dr\ue9panocytose homozygote et pour voir s'ils \ue9taient plus en pronation au d\ue9veloppement d'AL en comparaison avec les commandes normales de HbAA. M\ue9thode : Un total de 57 enfants avec dr\ue9panocytose homozygote entre les \ue2ges 1-15 ans \ue9taient prospectivement examin\ue9s pour la pr\ue9sence de l'Al en utilisant le temps de coagulation de kaolin (TCK), tandis que 52 enfants en bonne sant\ue9 de HbAA servaient de commandes. Le TCK a \ue9t\ue9 ex\ue9cut\ue9 en reproductions sur chacun des 109 sujets. La proportion de temps de coagulation de kaolin a \ue9t\ue9 calcul\ue9e pour d\ue9terminer la pr\ue9sence de l'AL. Une proportion sup\ue9rieure ou \ue9gale \ue0 1,2 a \ue9t\ue9 prise pour signifier la pr\ue9sence de l' AL. Les r\ue9sultats : Un (1,8 %) enfant avec dr\ue9panocytose homozogote avait prolong\ue9 le TCK, et ceci n'a pas \ue9t\ue9 corrig\ue9 par le plasma normal, la proportion de TCK \ue9tait plus grande que 1,2, signifiant la pr\ue9sence de l'AL. Aucun des sujets de contr\uf4le n'avait AL (p>0,05). Conclusion : Un (1,8%) enfant dans cette \ue9tude a eu l'AL ; cette valeur n'\ue9tait pas statistiquement significative en comparaison avec des commandes de HbAA. Malgr\ue9 le fait que l'AL secondaire est plus commune dans les femelles, le seul malade avec l'AL dans notre \ue9tude \ue9tait un m\ue2le et n'a eu aucune histoire ant\ue9rieure de ACV ou de thrombose

Environmental Heat Stress Among Young Working Women: A Pilot Study

BackgroundHeat waves are increasing significantly in frequency and severity and threaten the health and income of outdoor workers. Pregnant women workers are particularly at risk due to their delicate physiological systems and accountabilities to future generations. Animal and human studies propose that elevated body temperatures during pregnancy can induce adverse pregnancy outcomes.ObjectiveTo measure the change in internal body temperature (Tcore) in young working women before, after, and during work (both outdoor and indoor) on hot humid days and relate threshold temperature to the upshot adverse effects of pregnancy (teratogenicity and related miscarriage).MethodsTympanic temperatures were measured using infrared ear thermometers and workplace temperatures were collected using Lascar Data Logger. Brief exploratory interviews were conducted to gather qualitative data, and content analysis was also carried out.FindingsBody temperatures were found elevated among outdoor women workers compared with that of indoor women workers.ConclusionsThe present study found that outdoor work during pregnancy in hot, humid days might increase body temperature up to levels that could induce fetal destruction or anomaly

KANO MODEL APPROACH FOR DESIGN IMPROVEMENT ASSOCIATED WITH ERGONOMICS ISSUES IN CNC MACHINE DESIGN

Application of Computer Numerical Control (CNC) technology in manufacturing industry has been recognized as one of the effective solutions to high productivity, efficiency, and precision. In advancement of CNC machine tool technology development; however, the ergonomic issues related to human-machine design are still less-addressed by scholars. This study was carried out to analyze a CNC machining center based on the operators’ requirements. The functional and dysfunctional questionnaireform developed based on Kano method was applied to determine the operators’ requirements related to technical specifications of the CNC machining center. Another questionnaire form equipped with a diagram of human body parts and ergonomics features was used to acquire information on the CNC machining center design.This study found that there is a significant correlation between the ergonomics problems in the feet towards facilities required for theCNC machining center – an adjustable standing platform. This study concluded that application of Kano model can contribute to operators’ satisfaction in terms of ergonomic design of CNC machining center

Automatic Laser Welding Defect Detection and Classification using Sobel-Contour Shape Detection

This paper describes a detection of common defects in laser welding of structural aluminum alloy. To overcome these problems, a technique has been proposed to detect defects automatically and effectively using the image segmentation technique. Although, this technique has been well developed, it does suffer from several disadvantages of radiographic images taken to be poor in quality, as well as the microscopic size of the defects together with poor orientation relatively to the small size and thickness of the evaluated parts. Using image segmentation algorithm allows the defects to be automatically inspected and measured within the welded surface such as cracks, porosity and foreign inclusions, which may be weakening the welded parts. This paper proposes a system to automatically identifies and classifies the faults from the welding process by using the existing image segmentation algorithms. The output of the developed system produces a measured analysis which can be then used to describe the mechanical properties of welded part of the alloy such as its tensile and force. The benefits of this project will improve the welding process to reduce faults and defects for both constructing and manufacturing field

Research trends in combinatorial optimization

Acknowledgments This work has been partially funded by the Spanish Ministry of Science, Innovation, and Universities through the project COGDRIVE (DPI2017-86915-C3-3-R). In this context, we would also like to thank the Karlsruhe Institute of Technology. Open access funding enabled and organized by Projekt DEAL.Peer reviewedPublisher PD

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society