1,179 research outputs found
Quantitying the Effects of Traffic Calming on Emissions Using on-road Measurement
The objective of this work was to determine the effect of
one form of traffic calming on emissions. Traffic calming
is aimed at reducing average vehicle speeds, especially
in residential neighborhoods, often using physical road
obstructions such as speed bumps, but it also results in
a higher number of acceleration/deceleration events
which in turn yield higher emissions. Testing was
undertaken by driving a warmed-up Euro-1 spark ignition
passenger car over a set of speed bumps on a level
road, and then comparing the emissions output to a noncalmed
level road negotiated smoothly at a similar
average speed. For the emissions measurements, a
novel method was utilized, whereby the vehicle was
fitted with a portable Fourier Transform Infrared (FTIR)
spectrometer, capable of measuring up to 51 different
components in real-time on the road. The results
showed that increases in emissions were much greater
than was previously reported by other researchers using
different techniques. When traffic-calmed results were
compared to a smooth non-calmed road, there were
substantial increases in CO2 (90%), CO (117%), NOx
(195%) and THC (148%). These results form the basis
for a good argument against traffic calming using speed
bumps, especially for aggressive drivers. Slowing traffic
down with speed restrictions enforced by speed
cameras is a more environmentally friendly option
Evaluation of a FTIR Emission Measurement System for Legislated Emissions Using a SI Car
A series of chassis dynamometer test trials were
conducted to assess the performance of a Fourier
Transform Infra Red (FTIR) system developed for
on-road vehicle exhaust emissions measurements.
Trials used a EURO 1 emission compliant SI passenger
car which, alongside the FTIR, was instrumented to
allow the routine logging of engine speed, road speed,
throttle position, air-fuel ratio, air flow and fuel flow in
addition to engine, exhaust and catalyst temperatures.
The chassis dynamometer facility incorporated an
‘industry standard’ measurement system comprising
MEXA7400 gas analyzer and CVS bag sampling which
was the ‘benchmark’ for the evaluation of FTIR
legislated gas-phase emissions (CO, NOx, THC and
CO2) measurements.
Initial steady state measurements demonstrated strong
correlations for CO, NOx and THC (R2 of 0.99, 0.97
0.99, respectively) and a good correlation for CO2 (R2 =
0.92). Subsequent transient and total mass emissions
measurements from replicate samplings of four different
driving cycles (two standard cycles, FTP75 and NEDC,
and two novel cycles based on real-world data collected
in Leeds) also show good response of FTIR and
satisfied agreement between the FTIR and CVS bag
sampling measurements.
In general, the trial results demonstrate that the
on-board FTIR emission measurement system provides
reliable in-journey emissions data
Study of PDMS characterization and its applications in biomedicine: a review
Polydimethylsiloxane, also known as PDMS, has been widely used in the biomedical industry because of its biocompatible material and its biomechanical behavior is similar to biological tissues, with applications in the study of aneurysmal behavior and devices such as: Micro pumps, optical systems, microfluidic circuits. Many advances in research have been reached, but further tests are still necessary to understand the mechanical behavior and applicability of the material. For the study of PDMS behavior, two different techniques are employed: numerical and experimental. In experimental studies, it is extremely popular to use a field technique, in which the most appropriate technique to measure the field displacement of PDMS, without decorrelation, is the Digital Image Correlation (DIC) method. In this paper, we revised the most important experimental works with PDMS material and, simultaneously, we present its mechanical properties and its biomedical applications.info:eu-repo/semantics/publishedVersio
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Acceptance Test Report for the 241-AZ-101 Ultrasonic Interface Level Analyzer
This document comprises the Acceptance Test Report for the 241-AZ-101 Ultrasonic Interface Level Analyzer. This document presents the results of Acceptance Testing of the 241-AZ-101 Ultrasonic Interface Level Analyzers (URSILLAs). Testing of the URSILLAs was performed in accordance with ATP-260-001, ''URSILLA Pre-installation Acceptance Test Procedure''. The objective of the testing was to verify that all equipment and components function in accordance with design specifications and original equipment manufacturer's specifications
Numerical characterization of a hyperelastic material to shear stress
In last years, some studies have been proved that there is an association between the wall shear stress with intracranial aneurysm rupture, however, is very difficult to understand the mechanical tissue behaviour when subjected to shear stresses. In this work, it is implemented numerical simulations to characterise the polydimethylsiloxane (PDMS) material when it is subjected to a shear solicitation. For this, it was initially necessary to perform some experimental tests to characterize the mechanical behaviour of the material. Based on these results, several numerical simulations were performed with the most common constitutive models in the simulation of hyperelastic materials by varying numerical factors and parameters of the numerical models.info:eu-repo/semantics/publishedVersio
Characterization of shear strain on PDMS: numerical and experimental approaches
Polydimethylsiloxane (PDMS) is one of the most popular elastomers and has been used in
di erent fields, especially in biomechanics research. Among the many interesting features of this
material, its hyperelastic behavior stands out, which allows the use of PDMS in various applications,
like the ones that mimic soft tissues. However, the hyperelastic behavior is not linear and needs
detailed analysis, especially the characterization of shear strain. In this work, two approaches,
numerical and experimental, were proposed to characterize the e ect of shear strain on PDMS.
The experimental method was implemented as a simple shear testing associated with 3D digital
image correlation and was made using two specimens with two thicknesses of PDMS (2 and 4 mm).
A finite element software was used to implement the numerical simulations, in which four di erent
simulations using the Mooney–Rivlin, Yeoh, Gent, and polynomial hyperelastic constitutive models
were performed. These approaches showed that the maximum value of shear strain occurred in the
central region of the PDMS, and higher values emerged for the 2 mm PDMS thickness. Qualitatively,
in the central area of the specimen, the numerical and experimental results have similar behaviors and
the values of shear strain are close. For higher values of displacement and thicknesses, the numerical
simulation results move further away from experimental values.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: CIMO UIDB/00690/2020info:eu-repo/semantics/publishedVersio
q-Newton binomial: from Euler to Gauss
A counter-intuitive result of Gauss (formulae (1.6), (1.7) below) is made
less mysterious by virtue of being generalized through the introduction of an
additional parameter
Applications of the ACGT Master Ontology on Cancer
In this paper we present applications of the ACGT Master Ontology (MO) which is a new terminology resource for a transnational network providing data exchange in oncology, emphasizing the integration of both clinical and molecular data. The development of a new ontology was necessary due to problems with existing biomedical ontologies in oncology. The ACGT MO is a test case for the application of best practices in ontology development. This paper provides an overview of the application of the ontology within the ACGT project thus far
Abundance and evolution of galaxy clusters in cosmological models with massive neutrino
The time evolution of the number density of galaxy clusters and their mass
and temperature functions are used to constrain cosmological parameters in the
spatially flat dark matter models containing a fraction of hot particles
(massive neutrino) additional to cold and baryonic matter. We test the modified
MDM models with cosmic gravitational waves and show that they neither pass the
cluster evolution test nor reproduce the observed height of the first acoustic
peak in spectrum, and therefore should be ruled out. The models
with a non-zero cosmological constant are in better agreement with
observations. We estimate the free cosmological parameters in MDM with
a negligible abundance of gravitational waves, and find that within the
parameter ranges , , (i) the value of
is strongly affected by a small fraction of hot dark matter,
:
( CL), and (ii) the redshift evolution of galaxy clusters alone
reveals the following explicit correlation between and
: . The present accuracy of
observational data allows only to bound the fraction of hot matter, (the number of massive neutrino species remains undelimited, ).Comment: 9 pages, 7 figures, submitted in A&
Stress Concentration on PDMS: An evaluation of three numerical constitutive models using digital image correlation
The examination of hyperelastic materials’ behavior, such as polydimethylsiloxane (PDMS), is crucial for applications
in areas as biomedicine and electronics. However, the limitations of hyperelastic models for specific
stress scenarios, with stress concentration, are not well explored on the literature. To address this, firstly, three
constitutive models were evaluated (Neo-Hookean, Mooney-Rivlin, and Ogden) using numerical simulations and
Digital Image Correlation (DIC) analysis during a uniaxial tensile test. The samples were made of PDMS with
stress concentration geometries (center holes, shoulder fillets, and edge notches). Results of ANOVA analysis
showed that any of the three models can be chosen for numerical analysis of PDMS since no significant differences
in suitability were found. Finally, the Ogen model was chosen to obtain the stress concentration factors for
these geometries, a property which characterize how discontinuities change the maximum stress supported by an
element. Our study provides new values for variables needed to analyze and design hyperelastic elements and
produce a foundation for understanding PDMS stress-strain behavior.The authors acknowledge the projects EXPL/EME-EME/0732/2021
and 2022.06207.PTDC for the financial support, through national funds
(OE), within the scope of the Scientific Research and Technological
Development Projects (IC&DT) program in all scientific domains
(PTDC), PORTUGAL 2020 Partnership Agreement, European Regional
Development Fund (FEDER), via the Foundation for Science and Technology,
I.P. (FCT, I.P) and the R&D Units projects (UIDB/00690/2020
and UIDP/00690/2020) (CIMO), SusTEC (LA/P/0007/2020), UIDB/
04077/2020, UIDP/04077/2020, UIDB/04436/2020 and UIDB/00532/
2020. Andrews Souza acknowledges FCT for the Ph.D. scholarship
2021.07961.BD.info:eu-repo/semantics/publishedVersio
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