1,143 research outputs found
Formula SAE Intake System
The Formula SAE Intake System is intended to optimize the airflow into a restricted 600cc engine. The intake system is designed, fabricated, and installed in accordance with the FSAE rule book with a focus on maximizing the vehicle’s acceleration. It is directly responsible for determining the drivability of the car and how much horsepower the flow restricted engine produces.
Design of the intake was conceptualized based on researching a number of factors including venturi diffusion angles, plenum volumes, and runner lengths. Initial tests were performed utilizing computational fluid dynamics for a total of 367 flow simulations and 261 running hours on various intake components in SolidWorks Flow Simulation 2016. From the beginning, it was known that the intake needed to possess certain contours that would be very difficult to create with sheet metal. It was for this reason that a composite construction was pursued for the plenum of the intake manifold, utilizing fused deposition modeling to form the mold. Flow testing and dynamometer testing will be utilized to verify the effectiveness of the design. In the end, the intake system will provide peak performance in the flow restricted system. The increased brake horsepower and improved vehicle drivability will provide a competitive advantage on any race course.https://scholarscompass.vcu.edu/capstone/1198/thumbnail.jp
Pseudo-Dirac Neutrino Scenario: Cosmic Neutrinos at Neutrino Telescopes
Within the "pseudo-Dirac" scenario for massive neutrinos the existence of
sterile neutrinos which are almost degenerate in mass with the active ones is
hypothesized. The presence of these sterile neutrinos can affect the flavor
composition of cosmic neutrinos arriving at Earth after traveling large
distances from astrophysical objects. We examine the prospects of neutrino
telescopes such as IceCube to probe the very tiny mass squared differences
10^(-12) eV^2<\Delta m^2<10^(-19) eV^2, by analyzing the ratio of -track
events to shower-like events. Considering various sources of uncertainties
which enter this analysis, we examine the capability of neutrino telescopes to
verify the validity of the pseudo-Dirac neutrino scenario and especially to
discriminate it from the conventional scenario with no sterile neutrino. We
also discuss the robustness of our results with respect to the uncertainties in
the initial flavor ratio of neutrinos at the source.Comment: 24 pages, 5 figure
Analisa FRF secara teoritik dan eksperimental pada komponen struktur dengan profil pelat aluminium akibat eksitasi kejut dan random
The dynamic behaviour of the vibration system in the experimental analysis is observed from the response to the stimulus acting on it. In this case, the relationship between the stimulus at a certain location and direction is specifically related to its response respectively. The relationship between stimulus and response is called the Frequency Response Function (FRF) or better known as the transfer function. In measuring the transfer function, the stimulus to the structure is given in the form of an excitation force while the vibration response measurement depends on the type of sensor or transducer used. Diverging from the above problems, vibration testing is carried out on a structural model. This test uses an Aluminum beam as a specimen by using an excitation signal that comes from an exciter and an impact hammer. This research aims to examine the dynamic response in the form of vibration characteristics response in the frequency spectrum of an Aluminum beam. Based on this spectrum maps, we can observe the dominant frequency (a frequency with large amplitude). Furthermore, from these frequency data, it is expected to determine which frequency components are derived from component element defects and indications of resonance frequencies on machine elements or noise originating frequencies
2-Aminobenzoic acid–4-(pyridin-4-yldisulfanyl)pyridine (1/1)
The title 1:1 co-crystal, C7H7NO2·C10H8N2S2, features a highly twisted 4-(pyridin-4-yldisulfanyl)pyridine molecule [dihedral angle between the pyridine rings = 89.06 (10)°]. A small twist is evident in the 2-aminobenzoic acid molecule, with the C—C—C—O torsion angle being −7.7 (3)°. An N—H⋯O hydrogen bond occurs in the 2-aminobenzoic acid molecule. In the crystal, molecules are linked by O—H⋯N and N—H⋯N hydrogen bonds into a supramolecular chain along the b axis. These are connected into layers by π–π interactions occurring between pyridine rings [centroid–centroid distance = 3.8489 (15) Å]. The layers are connected along the a axis by C—H⋯O contacts. The crystal studied was a racemic twin
2-Phenylacetic acid–3-{(E)-2-[(E)-pyridin-3-ylmethylidene]hydrazin-1-ylidenemethyl}pyridine (2/1)
The asymmetric unit of the title 1:2 adduct, C12H10N4·2C8H8O2, comprises a single molecule of 2-phenylacetic acid and half a molecule of 3-pyridinealdazine; the latter is completed by crystallographic inversion symmetry. In the crystal, molecules are connected into a three-component aggregate via O—H⋯N hydrogen bonds. As the carboxyl group lies above the plane through the benzene ring to which it is attached [C—C—C—C = 62.24 (17)°] and the 4-pyridinealdazine molecule is almost planar (r.m.s. deviation of the 16 non-H atoms = 0.027 Å), the overall shape of the aggregate is that of a flattened extended chair. Layers of these aggregates are connected by C—H⋯O and C—H⋯π interactions and stack parallel to (220)
4-Aza-1-azoniabicyclo[2.2.2]octane–2-aminobenzoate–2-aminobenzoic acid (1/1/1)
A 4-aza-1-azoniabicyclo[2.2.2]octane cation, a 2-aminobenzoate anion and a neutral 2-aminobenzoic acid molecule comprise the asymmetric unit of the title compound, C6H13N2
+·C7H6NO2
−·C7H7NO2. An intramolecular N—H⋯O hydrogen bond occurs in the anion and in the neutral 2-aminobenzoic acid molecule. The cation provides a charge-assisted N—H⋯O hydrogen bond to the anion, and the 2-aminobenzoic acid molecule forms an O—H⋯N hydrogen bond to the unprotonated amino N atom in the cation. In this way, a three-component aggregate is formed. These are connected into a three-dimensional network by amino–carboxylate N—H⋯O hydrogen bonds. N—H⋯N hydrogen bonds are also observed
Elastic Compton Scattering from 3He and the Role of the Delta
We report observables for elastic Compton scattering from He in Chiral
Effective Field Theory with an explicit degree of freedom
(EFT) for energies between 50 and 120 MeV. The He amplitude
is complete at N3LO, , and in general converges well
order by order. It includes the dominant pion-loop and two-body currents, as
well as the Delta excitation in the single-nucleon amplitude. Since the cross
section is two to three times that for deuterium and the spin of polarised
He is predominantly carried by its constituent neutron, elastic Compton
scattering promises information on both the scalar and spin polarisabilities of
the neutron. We study in detail the sensitivities of 4 observables to the
neutron polarisabilities: the cross section, the beam asymmetry and two double
asymmetries resulting from circularly polarised photons and a longitudinally or
transversely polarised target. Including the Delta enhances those asymmetries
from which neutron spin polarisabilities could be extracted. We also correct
previous, erroneous results at N2LO, i.e.~without an explicit Delta, and
compare to the same observables on proton, neutron and deuterium targets. An
interactive Mathematica notebook of our results is available from
[email protected]: 37 pages LaTeX2e (pdflatex) including 16 figures as .pdf files using
includegraphics; minor corrections, triggered by referee comments, plus
typographical errors; text-identical to version published as EPJA 54 (2018)
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Human platelet activation by Escherichia coli: roles for FcγRIIA and integrin αIIbβ3
Gram-negative Escherichia coli cause diseases such as sepsis and hemolytic uremic syndrome in which thrombotic disorders can be found. Direct platelet–bacterium interactions might contribute to some of these conditions; however, mechanisms of human platelet activation by E. coli leading to thrombus formation are poorly understood. While the IgG receptor FcγRIIA has a key role in platelet response to various Gram-positive species, its role in activation to Gram-negative bacteria is poorly defined. This study aimed to investigate the molecular mechanisms of human platelet activation by E. coli, including the potential role of FcγRIIA. Using light-transmission aggregometry, measurements of ATP release and tyrosine-phosphorylation, we investigated the ability of two E. coli clinical isolates to activate platelets in plasma, in the presence or absence of specific receptors and signaling inhibitors. Aggregation assays with washed platelets supplemented with IgGs were performed to evaluate the requirement of this plasma component in activation. We found a critical role for the immune receptor FcγRIIA, αIIbβ3, and Src and Syk tyrosine kinases in platelet activation in response to E. coli. IgG and αIIbβ3 engagement was required for FcγRIIA activation. Moreover, feedback mediators adenosine 5’-diphosphate (ADP) and thromboxane A₂ (TxA₂) were essential for platelet aggregation. These findings suggest that human platelet responses to E. coli isolates are similar to those induced by Gram-positive organisms. Our observations support the existence of a central FcγRIIA-mediated pathway by which human platelets respond to both Gram-negative and Gram-positive bacteria
A new null diagnostic customized for reconstructing the properties of dark energy from BAO data
Baryon Acoustic Oscillations (BAO) provide an important standard ruler which
can be used to probe the recent expansion history of our universe. We show how
a simple extension of the Om diagnostic, which we call Om3, can combine
standard ruler information from BAO with standard candle information from type
Ia supernovae (SNIa) to yield a powerful novel null diagnostic of the
cosmological constant hypothesis. A unique feature of Om3 is that it requires
minimal cosmological assumptions since its determination does not rely upon
prior knowledge of either the current value of the matter density and the
Hubble constant, or the distance to the last scattering surface. Observational
uncertainties in these quantities therefore do not affect the reconstruction of
Om3. We reconstruct Om3 using the Union 2.1 SNIa data set and BAO data from
SDSS, WiggleZ and 6dFGS. Our results are consistent with dark energy being the
cosmological constant. We show how Om and Om3 can be used to obtain accurate
model independent constraints on the properties of dark energy from future data
sets such as BigBOSS.Comment: 9 pages, 4 figures, discussions extended, results unchanged, matches
the final version published in PR
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