Resonant Shattering of Neutron Star Crusts

The resonant excitation of neutron star (NS) modes by tides is investigated as a source of short gamma-ray burst (sGRB) precursors. We find that the driving of a crust-core interface mode can lead to shattering of the NS crust, liberating ~10^46-10^47 erg of energy seconds before the merger of a NS-NS or NS-black hole binary. Such properties are consistent with Swift/BAT detections of sGRB precursors, and we use the timing of the observed precursors to place weak constraints on the crust equation of state. We describe how a larger sample of precursor detections could be used alongside coincident gravitational wave detections of the inspiral by Advanced LIGO class detectors to probe the NS structure. These two types of observations nicely complement one another, since the former constrains the equation of state and structure near the crust-core boundary, while the latter is more sensitive to the core equation of state.Comment: 5 pages, 2 figures. Accepted to PR

Will black hole-neutron star binary inspirals tell us about the neutron star equation of state?

The strong tidal forces that arise during the last stages of the life of a black hole-neutron star binary may severely distort, and possibly disrupt, the star. Both phenomena will imprint signatures about the stellar structure in the emitted gravitational radiation. The information from the disruption, however, is confined to very high frequencies, where detectors are not very sensitive. We thus assess whether the lack of tidal distortion corrections in data-analysis pipelines will affect the detection of the inspiral part of the signal and whether these may yield information on the equation of state of matter at nuclear densities. Using recent post-Newtonian expressions and realistic equations of state to model these scenarios, we find that point-particle templates are sufficient for the detection of black hole-neutron star inspiralling binaries, with a loss of signals below 1% for both second and third-generation detectors. Such detections may be able to constrain particularly stiff equations of state, but will be unable to reveal the presence of a neutron star with a soft equation of state.Comment: 4 pages, 4 figure

The Influence of Online Advertising on the Consumer Behavior of Smartphone Customers

Purpose: The fundamental purpose of the study was to determine which domain of the online advertising significantly influence consumer buying behavior. Design/methodology/approach: This study employed a quantitative non-experimental research design utilizing correlational technique. The survey was conducted at Tagum City, Davao del Norte, Philippines. A total of 365 customers participated in this study. Findings: Results revealed that online advertising is much evident as perceived by the customers. On the other hand, the consumer buying behavior towards purchasing smartphones is much observed. The statistical result further revealed that there was a significant relationship between online advertising and consumer buying behavior of smartphone customers. Research limitations/implications: There are only two variables considered in this paper: Online advertising and consumer buying behavior; Intervening variables are not considered and the sample for this study is 365 using a random sampling method.  Practical implications: Among the five indicators, stimulation, brand recall, and necessity were found to have significantly predicted consumer buying behavior in purchasing smartphones. Originality/value: This paper is a collaborative effort of the researchers to understand consumer behavior of smartphone customers relative to online advertising. Paper type: Research paper &nbsp

Inferring the neutron star equation of state from binary inspiral waveforms

The properties of neutron star matter above nuclear density are not precisely known. Gravitational waves emitted from binary neutron stars during their late stages of inspiral and merger contain imprints of the neutron-star equation of state. Measuring departures from the point-particle limit of the late inspiral waveform allows one to measure properties of the equation of state via gravitational wave observations. This and a companion talk by J. S. Read reports a comparison of numerical waveforms from simulations of inspiraling neutron-star binaries, computed for equations of state with varying stiffness. We calculate the signal strength of the difference between waveforms for various commissioned and proposed interferometric gravitational wave detectors and show that observations at frequencies around 1 kHz will be able to measure a compactness parameter and constrain the possible neutron-star equations of state.Comment: Talk given at the 12th Marcel Grossman Meeting, Paris, France, 12-18 Jul 200

Tidal deformability of neutron stars with realistic equations of state and their gravitational wave signatures in binary inspiral

The early part of the gravitational wave signal of binary neutron star inspirals can potentially yield robust information on the nuclear equation of state. The influence of a star's internal structure on the waveform is characterized by a single parameter: the tidal deformability lambda, which measures the star's quadrupole deformation in response to the companion's perturbing tidal field. We calculate lambda for a wide range of equations of state and find that the value of lambda spans an order of magnitude for the range of equation of state models considered. An analysis of the feasibility of discriminating between neutron star equations of state with gravitational wave observations of the early part of the inspiral reveals that the measurement error in lambda increases steeply with the total mass of the binary. Comparing the errors with the expected range of lambda, we find that Advanced LIGO observations of binaries at a distance of 100 Mpc will probe only unusually stiff equations of state, while the proposed Einstein Telescope is likely to see a clean tidal signature.Comment: 12 pages, submitted to PR

Investigation of evaporation and condensation processes specific to grooved flat heat pipes

International audienceTemperature and liquid-vapor interface measurements obtained with a flat plate heat pipe (FPHP) in various experimental conditions are presented. The grooved FPHP is made of copper. The results are compared to a thermal model, developed in a previous work, in which heat conduction in the FPHP wall as well as evaporation and condensation heat transfer phenomena are taken into account. The model depends on the shape of the liquid-vapor interface in the grooves and on the fins at the condenser. A good agreement is found between the evaporation model and the experimental data. However the results of the condensation model overestimate the heat transfer coefficient, due to a bad estimation of the condensate film on the fins. Experimental measurements obtained with a second FPHP made of silicon are used to analyze the shape of this film. For both evaporation and condensation models, the results show a strong influence of the accommodation coefficient

Combined effects of the filling ratio and the vapour space thickness on the performance of a flat plate heat pipe

International audienceAn experimental study of a flat plate heat pipe (FPHP) is presented. Temperature fields in the FPHP are measured for different filling ratios, heat fluxes and vapour space thicknesses. The system is hermetically sealed with a transparent plate for meniscus curvature radius observations by confocal microscopy. Experimental results show that the liquid distribution in the FPHP - and thus its thermal performance - depends strongly on both the filling ratio and the vapour space thickness. A small vapour space thickness induces liquid retention and thus reduces the thermal resistance of the system. Nevertheless, the vapour space thickness influences the level of the meniscus curvature radii in the grooves and hence reduces the maximum capillary pressure. As a result, it has to be carefully optimised to improve the performance of the FPHP. In all the cases, the optimum filling is in the range one to two times the total volume of the grooves. A theoretical approach, in non working conditions, has been developed to model the distribution of the liquid inside the FPHP in function of the filling ratio and the vapour space thickness

Analysis of Pedestrian Performance by Integrating both Quantitative and Qualitative Factors

The importance of non-motorized movements, explicitly walking, and its corresponding impact on social, economic, and environmental aspects has always been overlooked due to the convenience brought by motorized vehicles. An automobile-dependent society mirrors the rise and worsening of several transportation problems, such as road-wide traffic congestion, massive fuel consumption, and excessive CO2emissions. In response to these aggravating situations and in support of various national and international calls, the main objective of this study was to extract the significant factors influencing the pedestrian level of service and walkability and to subsequently develop a predictive mathematical model for evaluating pedestrian conditions. Factors influencing the pedestrian level of service and walkability were initially identified through an extensive review and evaluation of existing studies, literature, and other relevant resources. A cause-and-effect analysis was used to develop an Ishikawa Diagram tackling pedestrian performance. The finalized factors were incorporated into the development of the Pedestrian Performance Assessment Questionnaire (PPAQ), which was utilized for data acquisition. Survey responses were then subjected to factor analysis after satisfying several tests for assumptions and suitability to extract the root causes influencing pedestrian performance. The validated root causes were then integrated to form the Pedestrian Performance Audit Tool (PPAT), a tool used in evaluating pedestrian areas in Tarlac City, Philippines. Data was analyzed through ordinal regression analysis to develop the multi-objective pedestrian performance prediction model. Results showed that there are six critical predictors of pedestrian performance unified in the final mathematical model: Pedestrian Space (PS), Official’s Intervention (OI), Ambiance (A), Vibrance (V), Street Vendors (SV), and Trash Bins (TB), and is the most significant contribution of the study. The model's validity was ascertained through a confusion matrix, which resulted in an acceptable rating. The comparison between calculated and perceived values together with the use of odds ratios served as the basis for the interpretation of some of the key results and findings. Finally, recommendations were also presented which can be a basis for the development of sustainable programs and interventions for the improvement of the pedestrian system. Doi: 10.28991/CEJ-2022-08-06-02 Full Text: PD