The potential of efficient water management system in high-rise design

Water is a natural gift upon all life forms since the early civilization of mankind and Malaysia is one of the nation that is rich with water resources. Since decades ago, the development in the water sector spurs the social economic growth of this country (Mohd. Azhar, 2000). As time goes by with rapid urbanisation across Malaysia, the demand for water especially in buildings, increase to accommodate a growing population and their needs. Roodman et al. (1995) and the United Nations Environment Programme (UNEP) (Al-Tamimi, 2011) highlight that the World watch Institute estimates building consumption to be at least 40% of the world’s energy and 16% of the water used annually. However, issues like increasing wastages and mismanagement of water leads to a problem towards this resources. Hence, the first part of the paper assesses the issues faced globally and locally towards water resources and the principles of water quality cascade in relation to sustainable water management in buildings. The next part are collective reviews of two selected case studies that include sustainable water management in the respective building design approach. The significant of this paper is to encourage the mind set of designers to contemplate and develop a more efficient water management system in high-rise buildings design as well as the importance for regulatory authorities and consultants to integrate the principles of sustainable water management onto development governing

The correlation of surface roughness and tool edge condition under sustainable cryogenic machining

This paper investigates the correlation between surface roughness of Inconel 718 and tool edge condition of ball nose inserts when milled at high speed. The cutting parameters were varied as follows; cutting speed: 120–140 m/min, feed rate: 0.15–0.25 mm/tooth, and axial depth of cut: 0.3–0.7 mm. For a sustainable machining approach, the experimental works were carried out under a smooth supply of cryogenic coolant which is a mix of liquid CO2, gas CO2, and compressed air. The experimental results revealed that the range of surface roughness obtained is from 0.114 to 0.197 µm. Along the cutting process, the tool wear patterns such as the abrasion, chipping, and the intermittent build-up-edge near the depth of cut cause the rapid increase of tool wear as well as the roughness of the machined surface with a significant correlation between them. However, the roughness was slowly reduced and became stable with the increase of notch wear. The finding could be used as a prediction reference for monitoring surface roughness and tool wear progress under cryogenic conditions. It also provides foundations for further research on machinability under this sustainable approach

Low Noise Amplifier For Front End Transceiver At 5.8 GHz

This paper presents the design of 5.8 GHz front end Low Noise Amplifier application for IEEE standard 802.11 systems for WLAN application. Revolution and demand of WLAN technology have urged development of low cost, low power and small size transceiver by using microstrip technology [1]. This paper is present design and simulation of single stage LNA circuits. This paper is focusing on development of Low Noise Amplifier operating at 5.75-5.85GHz (5GHz upper U-NII band) for WLAN application. The amplifier design used FHX76LP Low noise SuperHEMT from Eudyna Device USA Inc. The design circuit uses lumped elements to implement the matching networks. The purpose single stage of input and output matching network is to produces 50Ω impedance at the input and output port of the LNA. The matching network is used at both sides of the transistor [2],[3]. The target simulation are gain (S21)with >10dB, noise figure with <10dB and input and output return loss <-10dB at 5.8 GHz. A single stage LNA has successfully designed with 15.924 dB forward gain , 0.552 dB noise figure, -11.182 dB output return loss(S22) and -13.246 dB input return loss(S11) by using ADS software

Influences of Draw Forming Process on the Crash Analysis of a Circular Cup

The change of a structural part that occurred after forming process can affect crash response. Current industrial practice only utilizes the geometry in crash analysis. This study investigates the effect of forming histories of a circular cup formed by draw forming process in the crash simulation. Crash analysis at an initial velocity of 50km/h was performed using the explicit finite element code Radioss. The Johnson-Cook constitutive material model was used to characterize the material properties of advanced high strength steel DP600. Crash simulations are conducted in two different cases using a geometrical cup model with case 1 no forming history and case 2 all forming histories obtained from forming process. Results from this study indicate that the mechanical response of steel DP600 in a crash differ by 80.7 % for contact force and 5.87% for energy absorption when forming effects were considered. The contact force tends to increase more with displacement in case 2 compared to case 1. The non-uniform thickness and work hardening from forming process do alter significantly the crashworthiness of a structural part in the subsequent crash event

Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

[no abstract available

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. © 2022. The Author(s). Published by the American Astronomical Society

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

On the progenitor of binary neutron star merger GW170817

On 2017 August 17 the merger of two compact objects with masses consistent with two neutron stars was discovered through gravitational-wave (GW170817), gamma-ray (GRB 170817A), and optical (SSS17a/AT 2017gfo) observations. The optical source was associated with the early-type galaxy NGC 4993 at a distance of just ∼40 Mpc, consistent with the gravitational-wave measurement, and the merger was localized to be at a projected distance of ∼2 kpc away from the galaxy's center. We use this minimal set of facts and the mass posteriors of the two neutron stars to derive the first constraints on the progenitor of GW170817 at the time of the second supernova (SN). We generate simulated progenitor populations and follow the three-dimensional kinematic evolution from binary neutron star (BNS) birth to the merger time, accounting for pre-SN galactic motion, for considerably different input distributions of the progenitor mass, pre-SN semimajor axis, and SN-kick velocity. Though not considerably tight, we find these constraints to be comparable to those for Galactic BNS progenitors. The derived constraints are very strongly influenced by the requirement of keeping the binary bound after the second SN and having the merger occur relatively close to the center of the galaxy. These constraints are insensitive to the galaxy's star formation history, provided the stellar populations are older than 1 Gyr