Search results for " material"
showing 10 items of 17428 documents
Vortex dynamics in rotating counterflow and plane Couette and Poiseuille turbulence in superfluid Helium
2008
An equation previously proposed to describe the evolution of vortex line density in rotating counterflow turbulent tangles in superfluid helium is generalized to incorporate nonvanishing barycentric velocity and velocity gradients. Our generalization is compared with an analogous approach proposed by Lipniacki, and with experimental results by Swanson et al. in rotating counterflow, and it is used to evaluate the vortex density in plane Couette and Poiseuille flows of superfluid helium.
Like Parents, like Teenagers: A Romanian Youth Smoking Overview
2015
AbstractThis paper estimates how family model influences youth's smoking behaviors and describes smoking behavior in Romania nowadays. A questionnaire-based survey was used and data was collected from a national sample (1,364 people: 536 male and 828 female; average age 22,71 years and SD=3,128). The paper analyses only the items relevant for smoking behavior.Using a quasi-experimental design, we found a significant difference determinated by father's model (ρ(1364)= 0,158, p < 0,05), mother's model (ρ(1362)=0,155, p < 0,05), and brothers/sisters’ model (ρ(1362)=0,219, p < 0,05), regarding smoking behavior.Keywords: smoking behaviour, Romanian teenagers, parental model, Health Psychology
Finnish upper secondary level students' experiences and preferences of user-generated media content in the EFL classroom
2017
Kielten opiskelu on yhä multimodaalisempaa. Tutkimustieto tietyistä medioista ja välineistä luokkahuoneessa on kasvanut viimeisen vuosikymmenen aikana sekä kansainvälisesti, että Suomessa. Erityisesti opettajien näkemyksiä ja kokemuksia erilaisten internet materiaalien käytöstä osana opetusta on tutkittu, mutta tämän seurauksena oppilaiden näkökulma on jäänyt vähäiseksi. Tutkielman fokukseksi valikoitui käyttäjäkeskeiset mediat. Käyttäjäkeskeisillä medioilla tarkoitetaan internet materiaaleja, joiden sisältö on sivun käyttäjien tuottamaa ja jakamaa. Käyttäjäkeskeisten medioiden huomio keskittyy siis luovaan sisältöön ja sen tuottamiseen. Tästä hyviä esimerkkejä ovat muun muassa YouTube ja W…
Nuevos materiales inorgánicos mediante estrategias de síntesis biomiméticas
2015
Hace cincuenta años que un físico llamado Robert Feynman divisó el principio de la era nanotecnológica, en la que actualmente nos estamos adentrando. Lo que no llegó a imaginar, es hasta que punto se multiplicarían las aplicaciones en el mundo de lo extremadamente pequeño. Microrrobots que navegan por nuestras arterias, ordenadores del tamaño de una mota de polvo, materiales con propiedades extraordinarias e incluso algunos sistemas para eliminar residuos, son algunos de los prodigios que anuncia esta disciplina. Algunos ejemplos de los nuevos materiales que se podrían obtener gracias a la nanotecnología podrían ser: nanotubos de carbono para el desarrollo de células o pilas de combustible …
Polímeros de coordinación porosos biocompatibles y su aplicación en catálisis y remediación ambiental
2023
Esta tesis se enmarca en el campo de la Ciencia de Materiales y la Química de Coordinación, ya que se centra en el diseño de nuevos materiales porosos. Específicamente, explora la síntesis, caracterización y aplicaciones de nuevos Marcos Metal-Orgánicos (MOFs) basados en zinc. En general, los principales objetivos de esta tesis son dos. En primer lugar, obtener y caracterizar nuevos polímeros de coordinación porosos (MOFs) ensamblados con ligandos oxamidato derivados de biomoléculas como aminoácidos, así como metales biocompatibles como el zinc. En segundo lugar, estudiar las propiedades y aplicaciones potenciales de estos materiales. En este sentido, se pretende proporcionar ejemplos de ap…
Rac1-Regulated Endothelial Radiation Response Stimulates Extravasation and Metastasis That Can Be Blocked by HMG-CoA Reductase Inhibitors
2011
Radiotherapy (RT) plays a key role in cancer treatment. Although the benefit of ionizing radiation (IR) is well established, some findings raise the possibility that irradiation of the primary tumor not only triggers a killing response but also increases the metastatic potential of surviving tumor cells. Here we addressed the question of whether irradiation of normal cells outside of the primary tumor augments metastasis by stimulating the extravasation of circulating tumor cells. We show that IR exposure of human endothelial cells (EC), tumor cells (TC) or both increases TC-EC adhesion in vitro. IR-stimulated TC-EC adhesion was blocked by the HMG-CoA reductase inhibitor lovastatin. Glycyrr…
High Bias Voltage CZT Detectors for High-flux Measurements
2017
In this work, we present the performance of new travelling heater method (THM) grown CZT detectors, recently developed at IMEM-CNR Parma, Italy. Thick planar detectors (3 mm thick) with gold electroless contacts on CZT crystals grown by Redlen Technologies (Victoria BC, Canada) were realized, with a planar cathode covering the detector surface (4.1 x 4.1 mm(2)) and a central anode (2 x 2 mm(2)) surrounded by a guard ring electrode. The detectors, characterized by low leakage currents at room temperature (4.7 nA/cm(2) at 1000 V/cm), allow good room temperature operation even at high bias voltages (> 7000 V/cm). At low rates, the detectors exhibit an energy resolution around 4 % FWIEM at 59.5…
Strongly Coupled Coherent Phonons in Single-Layer MoS 2
2019
We present a transient absorption setup combining broadband detection over the visible-UV range with high temporal resolution ($\sim$20fs) which is ideally suited to trigger and detect vibrational coherences in different classes of materials. We generate and detect coherent phonons (CPs) in single layer (1L) MoS$_2$, as a representative semiconducting 1L-transition metal dichalcogenide (TMD), where the confined dynamical interaction between excitons and phonons is unexplored. The coherent oscillatory motion of the out-of-plane $A'_{1}$ phonons, triggered by the ultrashort laser pulses, dynamically modulates the excitonic resonances on a timescale of few tens fs. We observe an enhancement by…
STRUCTURAL OPTIMIZATION AND STRUCTURAL ANALYSIS OF COMPOSITE MATERIAL PANEL FOR NAVAL USE
2008
The purpose of the work is the realization of a composite material with long glass fibers having better characteristic than a fiber random composite, to permit the reduction of weight and costs to shipyards for pleasure craft. Structural optimization is performed by ANSYS for the choice of the layers disposition to obtain the maximum stiffness with minimum material employment, saving weight. The study is centered on the research of the better configurations of plies packing in relation of pure shear stress for four different plies. Unidirectional plies, both symmetric orthotropic and symmetric non-orthotropic ones, are realized successively by the vacuum bag technique. Experimental tests of…
The production cycle of lime based plasters in the Late Roman settlement of Scauri, Island of Pantelleria (Italy)
2016
This paper deals with the archaeometric study and analysis of lime based plasters recently found in the archaeological settlement of Scauri, located in the homonymous bay at the island of Pantelleria (central Mediterranean, Strait of Sicily). The Bay of Scauri is sited in the south-west part of the island. It can be considered a natural harbour overlooking the coast of Cape Bon in Tunisia. Since the 1999, the archaeological importance of place was reconsidered thanks to the recovering of huge remains of a Late Roman settlement dating back to the 4th-5th century AD. A production quarter, a residential area, a necropolis and a religious area were brought to light. The economy of the settlemen…