Search

We present a systematic search for optical counterparts to 13 gravitational wave (GW) triggers involving at least one neutron star during LIGO/Virgo's third observing run (O3). We searched binary neutron star (BNS) and neutron star black hole (NSBH) merger localizations with the Zwicky Transient Facility (ZTF) and undertook follow-up with the Global Relay of Observatories Watching Transients Happen (GROWTH) collaboration. The GW triggers had a median localization area of 4480 deg2, a median distance of 267 Mpc, and false-alarm rates ranging from 1.5 to 10-25 yr-1. The ZTF coverage in the g and r bands had a median enclosed probability of 39%, median depth of 20.8 mag, and median time lag between merger and the start of observations of 1.5 hr. The O3 follow-up by the GROWTH team comprised 340 UltraViolet/Optical/InfraRed (UVOIR) photometric points, 64 OIR spectra, and three radio images using 17 different telescopes. We find no promising kilonovae (radioactivity-powered counterparts), and we show how to convert the upper limits to constrain the underlying kilonova luminosity function. Initially, we assume that all GW triggers are bona fide astrophysical events regardless of false-alarm rate and that kilonovae accompanying BNS and NSBH mergers are drawn from a common population; later, we relax these assumptions. Assuming that all kilonovae are at least as luminous as the discovery magnitude of GW170817 (-16.1 mag), we calculate that our joint probability of detecting zero kilonovae is only 4.2%. If we assume that all kilonovae are brighter than-16.6 mag (the extrapolated peak magnitude of GW170817) and fade at a rate of 1 mag day-1 (similar to GW170817), the joint probability of zero detections is 7%. If we separate the NSBH and BNS populations based on the online classifications, the joint probability of zero detections, assuming all kilonovae are brighter than-16.6 mag, is 9.7% for NSBH and 7.9% for BNS mergers. Moreover, no more than 10-4, or φ > 30° to be consistent with our limits. We look forward to searches in the fourth GW observing run; even 17 neutron star mergers with only 50% coverage to a depth of-16 mag would constrain the maximum fraction of bright kilonovae to

Biodiesel has been chosen as a decent alternative to diesel in the context of establishing environmentally pleasant conditions and saving petroleum‐based resources for future generations. It is well‐established that biodiesel‐powered diesel engines may achieve outcomes equivalent to those of diesel engines. The current investigation was conducted to study the effect of injection pressure (190, 210, and 230 bar) and exhaust gas recirculation (EGR) (5%, 10%, and 15%) on a single‐cylinder variable compression ratio (VCR) diesel engine running using a B20 (20% MB + 80% PD) blend of microalgae biodiesel (MABD). This experiment was conducted in two stages. During the first stage of experimentation, the efficiency and emission characteristics of a diesel engine with a B20 blend of MABD at various fuel injection pressures and fresh air were investigated. During the second phase, fresh air was mixed with 5%, 10%, and 15% exhaust gases, and the experiment was conducted. It was discovered that increasing injection pressure to 230 bar provided considerable improvements. Brake thermal efficiency increased by 2.35%, brake‐specific fuel consumption decreased by 3.57% and pollutants such as carbon monoxide (CO), hydrocarbon, and smoke were reduced by more than 50% compared to conventional diesel. These reductions were similarly significant (over 22%) as compared to the B20 blend at lower injection pressure (210 bar). However, there was a slight trade‐off: nitrogen oxide (NOx) emissions increased partially (3.14%), while exhaust gas temperature (EGT) increased by 1.72% at a higher pressure. The study then investigated the influence of EGR (5%, 10%, and 15%) at various injection pressures. The optimal value seems to be 10% EGR at 230 bar injection pressure. This combination substantially reduced NOx emissions (by over 41% compared to the normal B20 blend) and EGT (by more than 8%), while having no notable effect on other performance or emission variables. Overall, the results show that employing a B20 MABD blend with high injection pressure (230 bar) and moderate EGR (10%) improves engine performance while reducing hazardous emissions. [ABSTRACT FROM AUTHOR]

Making use of the Hurwitz - Lerch zeta operator, we introduce a new subclass of analytic functions defined in the open unit disk and investigate its various characteristics. Further we obtain some usual properties of the geometric function theory such as coefficient bounds, extreme points, closure theorems radius of starlikness and convexity, partial sums and neighbourhood results belonging to the class. [ABSTRACT FROM AUTHOR]

A laboratory experiment was conducted to study the biology of pink bollworm Pectinophora gossypiella (Saunders) on cotton at four different temperature levels. It was found that males have a considerably shorter total life cycle duration on cotton at 35±1°C (29.5 days) followed by 30±1°C (37.2 days), 25±1°C (46.9 days) and highest at 20±1°C (50.8 days). Similarly, minimum total life cycle duration of female P. gossypiella was recorded at 35±1°C (30.2 days) followed by 30±1°C (38.0 days), 25±1°C (47.3 days) and maximum at 20±1°C (51.7 days). The highest fecundity was observed at 30±1°C (106.2) followed by 25±1°C (100.1), 35±1°C (60.1) and lowest at 20±1°C (55.2). Male as to female sex ratio was highest at 35±1°C (1:1.5) followed by 25±1°C (1:1.4), 30±1°C (1:1.3) and lowest at 20±1°C (1:1.2). These findings revealed that variation in temperature significantly influences the life cycle duration, fecundity and sex ratio of pink bollworms on cotton, with higher temperatures accelerating development and enhancing reproductive success. [ABSTRACT FROM AUTHOR]

A radial flow cell (RFC, inlet tube radius 0.95 mm and gaps of 1-4.2 mm) was used to investigate the removal of two thin (80-230 pm thick) model soil layers from glass and 304 stainless steel substrates by the flow of water at 20 °C. Under the flow conditions employed (Reynolds numbers 200-1400), inertial effects give rise to recirculation zones and regions of high shear stress on the bottom, soiled plate. The soils were dried layers of (i) instant coffee and (ii) a domestic abrasive cleaning suspension comprising fine particulates in a soluble matrix. Cleaning data exhibited a constant local erosion rate which varied strongly with radial position. For both soils, cleaning involved the growth of a circular cleaned region and redeposition of particulate matter in a ring at locations close to the foot of the secondary recirculation zone predicted by 2D axisymmetric CED simulations. Removal beyond this location was observed with the coffee layers, indicating that cleaning for this soil was controlled primarily by simple diffusion mechanisms. The effect of channel aspect ratio and flow rate on the location of recirculation zones and shear stress distributions was investigated. The local cleaning rate in these steady flows was not linked simply to local wall shear stress. [ABSTRACT FROM AUTHOR]

Solar water heating system is convincing technology to convert solar energy into thermal energy. According to the survey, approximately 42% of refined crude oil is used in industries and commercial applications for heating processes. Fossil fuel is the main energy source that is depleting continuously. Solar energy is an environment-friendly energy source, which can fulfill energy demand. Solar thermal collectors are most popular in domestic as well as industrial sectors for water heating due to their ease of operation and simple maintenance. Extensive work is going on to improve the thermal performance of solar thermal collectors using passive techniques. Passive techniques include the use of nanofluid, twisted tape, Phase Changing Materials. Active and passive techniques have a significant contribution to solar thermal collector thermal performance enhancement. This paper reviews the work carried out and current progress to enhance the thermal efficiency of solar water heaters using nanofluid. In addition to this, a detailed discussion and limitations of existing research have made from this discussion, research gaps are identified and possible future modifications are suggested. [ABSTRACT FROM AUTHOR]