Weak Solutions to the Degenerate Viscous Cahn-Hilliard Equation

The Cahn--Hilliard equation is a common model to describe phase separation processes of a mixture of two components. In this paper, we study the viscous Cahn--Hilliard equation with degenerate phase-dependent mobility. We define a notion of weak solutions and prove the existence of such weak solutions by considering the limits of the viscous Cahn--Hilliard equation with positive mobility. Also, we prove that such weak solutions satisfy an energy dissipation inequality under some additional conditions

Design of an Ultra-Wideband Frequency-Modulated Continuous Wave Short Range Radar System for Extending Independent Living

Falls in the disabled and elderly people have been a cause of concern as they can be immobilized by the fall and have no way to contact others and seek assistance. The proposed frequency modulated continuous wave (FMCW) short range radar (SRR) system, which uses ultra-wideband (UWB) signals can provide immediate assistance by monitoring and detecting fall events. The unique characteristics of this system allow for a frequency-based modulation system to carry out triangulation and sense the location of the fall through the usage of a continuous chirp signal that linearly sweeps frequency. This project focuses on the development, design and simulation of a ring oscillator that exhibits the frequency modulated signal on a single integrated circuit chip. The ring oscillator is controlled by a voltage ramp signal generator and a voltage to current (V-I) converter. The circuit is designed in Cadence using TSMC 180nm process technology and operates in the frequency range of 3.409 GHz to 5.349 GHz with a spectral bandwidth of 1.94 GHz, which meets the Federal Communications Commission’s standards for unlicensed ultra-wideband transmissions

Universal classification of twisted, strained and sheared graphene moir\'e superlattices

Moir\'e superlattices in graphene supported on various substrates have opened a new avenue to engineer graphene's electronic properties. Yet, the exact crystallographic structure on which their band structure depends remains highly debated. In this scanning tunneling microscopy and density functional theory study, we have analysed graphene samples grown on multilayer graphene prepared onto SiC and on the close-packed surfaces of Re and Ir with ultra-high precision. We resolve small-angle twists and shears in graphene, and identify large unit cells comprising more than 1,000 carbon atoms and exhibiting non-trivial nanopatterns for moir\'e superlattices, which are commensurate to the graphene lattice. Finally, a general formalism applicable to any hexagonal moir\'e is presented to classify all reported structures.Comment: 14 pages, 6 figure

Prétraitement et post-traitement pour le codec MPEG1

Le standard de compression MPEG1 a pour but d'offrir une grande compression du signal vidéo tout en conservant la qualité de l'image acceptable. À un débit aux alentours de 4 à 5 Mbit/s, la compression MPEG1 effectue en général une tâche remarquable. Par contre, à un débit de 1.2 Mbit/s visé pour les disques compacts, le codec éprouve des difficultés lorsque la source contient beaucoup de détails et de mouvements. Il introduit ainsi des artefacts dans les images de sortie. Ce travail de recherche vise à réduire ces artefacts afin d'améliorer la qualité des images à la sortie du codec et de réduire le débit de transmission. Pour y parvenir, les deux systèmes de traitement proposés sont le prétraitement et le post-traitement.Le prétraitement élabore en premier lieu une conversion de format CCIR 601 en format SIF adéquate afin de réduire le repliement spectral vertical existant dans le SIF standard. Suite à cela, un filtrage de forme losange est introduit pour aider l'encodeur à compresser plus efficacement. Quant au post-traitement, il débute par un filtrage de forme losange, compatible avec celui de l'encodeur, qui permet d'atténuer les bruits aléatoires et partiellement l'effet de bloc. Ensuite, pour réduire le bruit de moustique résiduel, un système de filtrage adaptatif spatial est proposé. Finalement, la conversion inverse de format SIF en format original CCIR 601, basée sur l'interpolation temporelle, complète le système de post-traitement

Contribution à l'utilisation du lactulose comme additif fonctionnel dans la fabrication de pain riche en son de blé

Ce projet a démontré la faisabilité de fabrication de pain à base de farine riche en son de blé additionnée de lactulose jusqu'à 5%. La pâte enrichie de lactulose est caractérisée par une acidité titrable légèrement inférieure au témoin. Ceci est attribuable à l'incapacité des levures à fermenter le lactulose. La cuisson a montré que l'ajout de lactulose à la formule de pain à un niveau allant jusqu'à 5% n'a pas d'incidence négative sur la qualité du pain. L'évaluation visuelle et sensorielle a montré que l'ajout de 5% de lactulose à la formulation de pain de blé ne modifie pas le profil de texture du produit. La structure de la mie du pain témoin est légèrement plus poreuse que celle du pain additionné de lactulose à 5%. Le volume massique du pain est également plus faible, ce qui indique que des changements de texture se sont produits, mais restent acceptables

A contribution to the phytochemical survey of Peninsular Malaysia

Specimens of 216 plants representing 150 genera and 50 families were collected from four areas in the western and central parts of Peninsular Malaysia. The leaves ofeach species were screened for alkaloids, steroids and triterpenes, and for saponins. 28 specz'es (13%) gave a positive test for alkaloids, 86 (40%) for saponins and 55 (25%) for triterpeneslsteroids

Improving Lung Cancer Screening Selection:The HUNT Lung Cancer Risk Model for Ever-Smokers Versus the NELSON and 2021 United States Preventive Services Task Force Criteria in the Cohort of Norway: A Population-Based Prospective Study

Background: Improving the method for selecting participants for lung cancer (LC) screening is an urgent need. Here, we compared the performance of the Helseundersøkelsen i Nord-Trøndelag (HUNT) Lung Cancer Model (HUNT LCM) versus the Dutch-Belgian lung cancer screening trial (Nederlands-Leuvens Longkanker Screenings Onderzoek (NELSON)) and 2021 United States Preventive Services Task Force (USPSTF) criteria regarding LC risk prediction and efficiency. Methods: We used linked data from 10 Norwegian prospective population-based cohorts, Cohort of Norway. The study included 44,831 ever-smokers, of which 686 (1.5%) patients developed LC; the median follow-up time was 11.6 years (0.01–20.8 years). Results: Within 6 years, 222 (0.5%) individuals developed LC. The NELSON and 2021 USPSTF criteria predicted 37.4% and 59.5% of the LC cases, respectively. By considering the same number of individuals as the NELSON and 2021 USPSTF criteria selected, the HUNT LCM increased the LC prediction rate by 41.0% and 12.1%, respectively. The HUNT LCM significantly increased sensitivity (p &lt; 0.001 and p = 0.028), and reduced the number needed to predict one LC case (29 versus 40, p &lt; 0.001 and 36 versus 40, p = 0.02), respectively. Applying the HUNT LCM 6-year 0.98% risk score as a cutoff (14.0% of ever-smokers) predicted 70.7% of all LC, increasing LC prediction rate with 89.2% and 18.9% versus the NELSON and 2021 USPSTF, respectively (both p &lt; 0.001). Conclusions: The HUNT LCM was significantly more efficient than the NELSON and 2021 USPSTF criteria, improving the prediction of LC diagnosis, and may be used as a validated clinical tool for screening selection.</p

Slip Resistance Test Apparatus of Synthetic Rubber Trackpad on Photovoltaic Surface

The increasing development of the solar energy industry in many countries has led to a rising frequency of human and robot presence in this area. To ensure occupational safety, various protective equipment, including rubber material, is commonly used for slip resistance while moving on the surface of solar PV panels. Therefore, the slip resistance test apparatus is built for testing the slip resistance between the synthetic rubber trackpad and the photovoltaic panel (PV) surface. Synthetic rubber is a man-made material, so it is difficult to control the parameters of its mechanical and chemical properties absolutely. Variations in wet/dry working conditions or Shore hardness are factors that make slip computation more challenging. Therefore, an apparatus with the principle of converting the reciprocating motion of the screw and the casters into the rotation of the hinge is introduced to adjust the tilt angle of the upper surface, detect and evaluate the slippage of the rubber trackpad by sensors. Some parameters related to accuracy such as vibration and theoretical-empirical assessment, are also mentioned. In addition to designing a reliable apparatus, the article also succeeded in providing a safety standard for synthetic rubber with Shore A30-A40 when moving on PV surfaces.Comment: 4 pages, 10 figures, The 20th International Conference on Ubiquitous Robots (UR 2023

Modeling of parallel power MOSFETs in steady-state

In high-power applications, multiple power MOSFETs are connected in parallel and treated as a single switch in order to handle much larger total currents. In this paper, a parallel power MOSFETs model from the turnoff state until they reach their steady state is introduced. The model represents the relationship between each power MOSFET's gate voltage and the current distribution among them. The study's key purpose is to use the model for dealing with the asymmetry in sharing current and power loss between these semiconductor devices during the steady state region.Comment: 10 pages, 7 figures, The 2023 INTERNATIONAL SYMPOSIUM ON ADVANCED ENGINEERING (ISAE2023