8,136 research outputs found
Vortex Lattice in Bi_{2}Sr_{2}CaCu_{2}O_{8+\delta} Well Above the First-Order Phase-Transition Boundary
Measurements of non-local in-plane resistance originating from transverse
vortex-vortex correlations have been performed on a
Bi_{2}Sr_{2}CaCu_{2}O_{8+\delta} high-T_c superconductor in a magnetic field up
to 9 T applied along the crystal c-axis. Our results demonstrate that a rigid
vortex lattice does exist over a broad portion of the magnetic field --
temperature (H-T) phase diagram, well above the first-order transition boundary
H_{FOT}(T). The results also provide evidence for the vortex lattice melting
and vortex liquid decoupling phase transitions, occurring above the H_{FOT}(T).Comment: 14 pages, 10 figure
Kajian Kinerja Pelayanan Terminal Angkutan Umum (Studi Kasus Terminal Becora Dili - Timor Leste)
Kajian Kinerja Pelayanan Terminal Angkutan Umum (Studi Kasus Terminal Becora Dili - Timor Leste)The Study of Terminal Performance Service of Public Transportation (Case Study Becora Terminal Dili-East Timor)Nelson Francisco A.D.S.Silva1, Harnen Sulistio2, Sobri Abusini31,2,3Jurusan Teknik Sipil, Fakultas Teknik Universitas BrawijayaAlamat korespondensi : Jln. MT. Haryono, No 167 Malange-mail: [email protected] transportation terminal constitute of transportation node that function as a place of passenger transit to the other mode of transportation. The study was conducted at Becora terminal in period of time shown less optimum performance services and poor facility condition as standardized for a type B terminal. The objective of study was to find out factors influencing operational performance in Becora terminal, to make recommendation by increasing terminal performance regarding to terminal customer service and also the formula regression model the correlation between quality service and influential variables. Data analysis to be down by importance performance analysis (IPA) methods and quality funcitional deploymen(QFD) methods, also regression analysis to create predictable model and simulation of influential correlation between service variable to quality service. The result of IPA analysis shown 14 attributes of services stayed in I quadran wich become to principal priority of rehabilitation , whereas the QFD shown 8 technical response collected for rehabilitation attribute of service. Model to be obtained by multiple linear regression analysis were Y= -0,328 + 0.276 X3 with value R2 = 0.274 so that comfortable variables (X3) become influential variables 72.4 % regarding to quality service.Keywords: Terminal, IPA analysis, QFD AnalysisAbstrakTerminal angkutan umum merupakan salah satu simpul transportasi yang berfungsi sebagai tempat transit penumpang untuk beralih ke moda angkutan umum lain. Kajian dilakukan pada Terminal Becora yang pada saat ini kinerja Pelayanannya kurang optimal dan kondisi fasilitas pelayanan terminal yang masih sangat minim dari yang distandarkan oleh suatu terminal tipe B. Tujuan pada penelitian ini adalah untuk mengetahui faktor-faktor yang mempengaruhi kinerja operasional terminal Becora, membuat rekomendasi guna meningkatan kinerja Terminal terhadap kepuasaan pengguna jasa terminal serta membuat model regresi hubungan antara kualitas pelayanan dan variabel yang mempengaruhinya. Analisa data dilakukan dengan metode IPA (importance performance analysis) dan metode quality funcitional deployment (QFD) serta analisa regresi untuk membuat model prediksi dan simulasi pengaruh hubungan yang terjadi antara variabel pelayanan dengan kualitas pelayanan. Hasil analisa IPA menunjukkan 14 atribut pelayanan berada di kuadran I yang menjadi prioritas utama perbaikan, sedangkan pada analisa quality functional deployment (QFD) didapatkan 8 respon teknis yang dapat dilakukan untuk perbaikan atribut-atribut pelayanan tersebut. Model yang didapatkan dari analisa regresi linear berganda yaitu: Y= -0
Exchange interaction effects in the thermodynamic properties of quantum dots
We study electron-electron interaction effects in the thermodynamic
properties of quantum-dot systems. We obtain the direct and exchange
contributions to the specific heat C_v in the self-consistent Hartree-Fock
approximation at finite temperatures. An exchange-induced phase transition is
observed and the transition temperature is shown to be inversely proportional
to the size of the system. The exchange contribution to C_v dominates over the
direct and kinetic contributions in the intermediate regime of interaction
strength (r_s ~ 1). Furthermore, the electron-electron interaction modifies
both the amplitude and the period of magnetic field induced oscillations in
C_v.Comment: 4 pages, 4 figures; To appear in Phys. Rev.
Do ultrafast exciton-polaron decoherence dynamics govern photocarrier generation efficiencies in polymer solar cells?
All-organic-based photovoltaic solar cells have attracted considerable
attention because of their low-cost processing and short energy payback time.
In such systems the primary dissociation of an optical excitation into a pair
of photocarriers has been recently shown to be extremely rapid and efficient,
but the physical reason for this remains unclear. Here, two-dimensional
photocurrent excitation spectroscopy, a novel non-linear optical spectroscopy,
is used to probe the ultrafast coherent decay of photoexcitations into
charge-producing states in a polymer:fullerene based solar cell. The
two-dimensional photocurrent spectra are interpreted by introducing a
theoretical model for the description of the coupling of the electronic states
of the system to an external environment and to the applied laser fields. The
experimental data show no cross-peaks in the two-dimensional photocurrent
spectra, as predicted by the model for coherence times between the exciton and
the photocurrent producing states of 20\,fs or less
The Hubble Rate Trouble: An Effective Field Theory of Dark Matter
The Hubble constant inferred from the 6-parameter fit to the CMB power
spectrum conflicts with the value obtained from direct measurements via type Ia
supernova and Cepheids observations. We write down effective operators
involving spin-0, spin-1/2, and spin-1 dark matter that lead to the
relativistic production of dark matter particles at early times, and
consequently lead to an increase in the number of relativistic degrees of
freedom. This mechanism which is amenable to CMB, BBN, and structure formation
observables can sufficiently raise the value of the Hubble constant derived
from CMB and reconcile local and CMB probes of the Hubble constant. This
mechanism alone increases up to , and with
the help of a Phantom-like cosmology, reach . Lastly, we outline the region of parameter space which reproduces
while obeying all relevant
constraints.Comment: 10 pages and 14 figure
Unveiling the Dynamics of the Universe
We explore the dynamics and evolution of the Universe at early and late
times, focusing on both dark energy and extended gravity models and their
astrophysical and cosmological consequences. Modified theories of gravity not
only provide an alternative explanation for the recent expansion history of the
universe, but they also offer a paradigm fundamentally distinct from the
simplest dark energy models of cosmic acceleration. In this review, we perform
a detailed theoretical and phenomenological analysis of different modified
gravity models and investigate their consistency. We also consider the
cosmological implications of well motivated physical models of the early
universe with a particular emphasis on inflation and topological defects.
Astrophysical and cosmological tests over a wide range of scales, from the
solar system to the observable horizon, severely restrict the allowed models of
the Universe. Here, we review several observational probes -- including
gravitational lensing, galaxy clusters, cosmic microwave background temperature
and polarization, supernova and baryon acoustic oscillations measurements --
and their relevance in constraining our cosmological description of the
Universe.Comment: 94 pages, 14 figures. Review paper accepted for publication in a
Special Issue of Symmetry. "Symmetry: Feature Papers 2016". V2: Matches
published version, now 79 pages (new format
Um modelo de crescimento de Paleosuchus trigonatus (Crocodylia: Alligatoridae) do Rio Negro prevê o crescimento de indivíduos do rio Xingu, Brasil
Patterns of growth of crocodilians vary geographically within the same species, so models developed in one area may not predict size-age relationships in others. We used recapture data for three females and six males of Paleosuchus trigonatus from the Belo Monte hydroelectric dam area on the Xingu River to validate a growth model developed on a tributary of the Rio Negro. Individuals were recaptured between two and 10 years after marking (2012–2022). The data indicate that the monomolecular (von Bertalanffy by length) model is adequate to model growth of intermediate size animals. Recapture of one female after eight years indicates that the Rio Negro model can be used to model growth with accuracy for individuals from the Xingu River.Os padrões de crescimento dos crocodilianos variam geograficamente dentro da mesma espécie, de modo que os modelos desenvolvidos em uma área não preveem relações tamanho-idade em outras. Usamos dados de recaptura de três fêmeas e seis machos de Paleosuchus trigonatus da área da hidrelétrica de Belo Monte no rio Xingu para validar um modelo de crescimento desenvolvido em um afluente do rio Negro. Os jacarés foram recapturados entre dois e dez anos após a marcação (2012–2022). Os dados indicam que o modelo monomolecular (von Bertalanffy por comprimento) é adequado para modelar o crescimento de animais de tamanho intermediário, e a recaptura de uma fêmea após oito anos indica que o modelo Rio Negro pode ser usado para modelar o crescimento com razoável precisão para indivíduos do Rio Xingu
Neurotoxicity of Micrurus lemniscatus lemniscatus (South American coralsnake) venom in vertebrate neuromuscular preparations in vitro and neutralization by antivenom
We investigated the effect of South American coralsnake (Micrurus lemniscatus lemniscatus) venom on neurotransmission in vertebrate nerve-muscle preparations in vitro. The venom (0.1-30 µg/ml) showed calcium-dependent PLA2 activity and caused irreversible neuromuscular blockade in chick biventer cervicis (BC) and mouse phrenic nerve-diaphragm (PND) preparations. In BC preparations, contractures to exogenous acetylcholine and carbachol (CCh), but not KCl, were abolished by venom concentrations ≥ 0.3 µg/ml; in PND preparations, the amplitude of the tetanic response was progressively attenuated, but with little tetanic fade. In low Ca2+ physiological solution, venom (10 µg/ml) caused neuromuscular blockade in PND preparations within ~ 10 min that was reversible by washing; the addition of Ca2+ immediately after the blockade temporarily restored the twitch responses, but did not prevent the progression to irreversible blockade. Venom (10 µg/ml) did not depolarize diaphragm muscle, prevent depolarization by CCh, or cause muscle contracture or histological damage. Venom (3 µg/ml) had a biphasic effect on the frequency of miniature end-plate potentials, but did not affect their amplitude; there was a progressive decrease in the amplitude of evoked end-plate potentials. The amplitude of compound action potentials in mouse sciatic nerve was unaffected by venom (10 µg/ml). Pre-incubation of venom with coralsnake antivenom (Instituto Butantan) at the recommended antivenom:venom ratio did not neutralize the neuromuscular blockade in PND preparations, but total neutralization was achieved with a tenfold greater volume of antivenom. The addition of antivenom after 50% and 80% blockade restored the twitch responses. These results show that M. lemniscatus lemniscatus venom causes potent, irreversible neuromuscular blockade, without myonecrosis. This blockade is apparently mediated by pre- and postsynaptic neurotoxins and can be reversed by coralsnake antivenom
Numerical simulation of the flow inside a horizontal closed refrigerated display cabinet
A refrigerated display cabinet is a device often used to preserve the products contained inside while enabling the costumer to have a view to the products stored. The main objective of this work was to investigate, using the ANSYS Fluent software, the airflow in a horizontal closed refrigerated display cabinet to better understand the fluid flow behavior in its interior. The turbulent airflow and non-isothermal heat transfer process were computed in a 2D transient state mathematical model where the basic equations governing the transport phenomena inside of the refrigerated display cabinet were solved. Regarding the turbulence model, this was modeled with the three-equation model since it can address the boundary-layer transition regions within the cabinet. After a complete understanding of the fluid flow behavior inside the cabinet, the influence of the door opening was analyzed. Results of the CFD simulations allowed to achieve a detailed mapping of the cooling process inside the equipment. Generally, stabilizing the interior temperature for an empty cabinet is rapidly achieved with minimal heat losses. The inclusion of products that are at a higher temperature than the cooling air creates a zone of high thermal inertia and makes the temperature stabilization a longer process. Even though specific equipment is used, the results provide standard information on the phenomena occurring inside the cabinet and contribute to the industry and academic society to understand and improve industrial products and obtain more information that is very reduced in the literature.This work has been supported by the Portuguese Foundation for Science and Technology (FCT) within the R&D Units Project Scope UIDB/00319/2020 (ALGORITMI) and R&D Units Project Scope UIDP/04077/2020 (METRICS). The first author would like to express his gratitude for the support given by the FCT through the PhD Grant SFRH/BD/130588/2017
Global persistence exponent of the two-dimensional Blume-Capel model
The global persistence exponent is calculated for the
two-dimensional Blume-Capel model following a quench to the critical point from
both disordered states and such with small initial magnetizations.
Estimates are obtained for the nonequilibrium critical dynamics on the
critical line and at the tricritical point.
Ising-like universality is observed along the critical line and a different
value is found at the tricritical point.Comment: 7 pages with 3 figure
- …