Targeted Energy Transfer and Modal Energy Redistribution in Automotive Drivetrains

The new generations of compact high output power-to-weight ratio internal combustion engines generate broadband torsional oscillations, transmitted to lightly damped drivetrain systems. A novel approach to mitigate these untoward vibrations can be the use of nonlinear absorbers. These act as Nonlinear Energy Sinks (NESs). The NES is coupled to the primary (drivetrain) structure, inducing passive irreversible targeted energy transfer (TET) from the drivetrain system to the NES. During this process, the vibration energy is directed from the lower-frequency modes of the structure to the higher ones. Thereafter, vibrations can be either dissipated through structural damping or consumed by the NES. This paper uses a lumped parameter model of an automotive driveline to simulate the effect of TET and the assumed modal energy redistribution. Significant redistribution of vibratory energy is observed through TET. Furthermore, the integrated optimization process highlights the most effective configuration and parametric evaluation for use of NES

Localization and broadband follow-up of the gravitational-wave transient GW150914

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline, and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams

Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 × 10−21. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410þ160 −180 Mpc corresponding to a redshift z ¼ 0.09þ0.03 −0.04 . In the source frame, the initial black hole masses are 36þ5 −4M⊙ and 29þ4 −4M⊙, and the final black hole mass is 62þ4 −4M⊙, with 3.0þ0.5 −0.5M⊙c2 radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger

Search for gravitational waves associated with gamma-ray bursts detected by Fermi and Swift during the LIGO–Virgo run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate

A review dengue incidence in Kota Bharu, Kelantan from year 1998-2003

Dengue is the most common and widespread arthropod borne arboviral infection in the world today. It is estimated that there are at least 100 million cases of dengue fever (DF) annually and 500,000 cases of dengue hemorrhagic fever (DHF) which require hospitalization. In Malaysia, it has become one of the major public health problems. The incidence rate of clinically diagnosed DF and DHF reported is showing an upward trend from 8.5 cases/l00,000 populations in 1988 to 88.6 cases/100, 000 populations in 2003. The objective of this analysis was to describe the incidence of dengue fever and dengue hemorrhagic fever in Kota Bharu, Kelantan from year 1998-2003. A total of 4716 dengue cases were notified involving 4476 (94.9%) DF and 240 (5.1%) DHF, which was increasing by years. The highest incidence was in January (701 or 14.9%) while the lowest was in May (188 or 4.0%). Forty percent of cases (n=1890) were in the 15-29 years old group. Majorities were Malays (4062 or 86.1%) and 2602 or 55.2% were male. A total of 4477 cases (95%) were local cases and 4289 or 91% came from urban area. For priority areas, 3772 (80%) were from priority 1. More than half of cases have positive serology result. The mean values for age, temperature, systolic and diastolic blood pressure (BP) were 27.8 + 15.4 years, 37.9 + 0.9 degree Celcius, 115 + 15.2mmHg and 73 + 11.1mmHg respectively. The mean value for time interval befween onset of symptoms and diagnosis, onset of symptoms and notification and time of diagnosis to notification were 5.1 + 2.3, 5.9 + 2.5 and 0.8 + 1.1 days respectively. All symptoms occurred in more than 96% of cases and fever was the commonest (99.7%). The incidence of dengue in Kota Bharu is comparable to that of in Malaysia. The increase in the number of cases needs to be addressed promptly with effective surveillance, prevention and control programs

Reconceptions Of Health Education In The Time Of Covid-19 According To The Perspective Of The Islamic Boarding School

The concept of health during the COVID-19 period has changed, especially in the world of Islamic Boarding Schools. The existence of this reconception because the pandemic conditions influenced it since March 2020 that hit Indonesia. This paper aims to examine three things: first, the form of a reconception of health education during the COVID-19 pandemic from the perspective of Islamic Boarding Schools; second, the implementation of the reconceptualization of health education in real life in the pesantren community; third, the reconceptualization of health education as a solution during the pandemic. The method used is through interviews (with Kiai, Ustadz (Teacher) and Santri (Student)), observation of pesantren and documentation in the text of the Qur'an and the hadith of the prophet. The results are three things: first, a form of reconception, that health education is a top priority, worship requires physical and mental health; second, the application of reconception in the life of the pesantren community is influenced by three factors: intentional which is the motive of the pesantren, internal conditions within the pesantren, and external conditions outside the pesantren; third, the reconception of health education from the perspective of pesantren as a solution during a pandemic, namely being more careful in interpreting texts about the disease, improving health care, pesantren opening up and protecting public healt