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The Effect of Cyperus Odoratus Size and Loading on the Properties of Polypropylene/Cyperus Odoratus (PP/CY) Composites

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Journal of Physics: Conference Series 2018年第1期1019卷

作者： Omar S Dahham N Z Noriman R Hamzah S Sudin S Z Syed Idrus Z Shayfull T Adam Center of Excellence Geopolymer and Green Technology (CEGeoGTech) Faculty of Engineering Technology (FETech) Universiti Malaysia Perlis (UniMAP) Level 1 Block S2 UniCITI Alam Campus Sungai Chucuh Padang Besar 02100 Perlis Malaysia. School of Human Development and Techno-communication (iKOM) Green Advanced Computing and Technology (GREAT) Research Group – CEGeoGTech Universiti Malaysia Perlis (UniMAP School of Manufacturing Engineering Universiti Malaysia Perlis Arau 02600 Malaysia Green Design and Manufacture Research Group Center of Excellence Geopolymer and Green Technology (CEGeoGTech) Universiti Malaysia Perlis Kangar 0100 Malaysia Institute of Nano Electronic Engineering (INEE) Universiti Malaysia Perlis (UniMAP) 01000 Kangar Perlis Malaysia

In this research, a new bio-plastic composite was developed using Cyperus Odoratus (CY) as natural filler along with Polypropylene (PP) matrix. PP/CY composites were prepared using different CY size, fine size at (0-63) and coarse size at (150-250 ) and using different PP/CY ratio at (100/0, 95/5, 90/10 and 85/15). The extrusion process followed by injection molding process was conducted for PP/CY composites fabrication. The tensile and morphological characteristics of PP/CY samples were evaluated. The results suggest that the addition of CY content (fine size) up to 95/5 PP/CY ratio gave highest tensile strength (TS) value. The increasing of CY content, particularly CY coarse size into PP/CY composites has decreased the TS. By contrast, the high CY content, particularly CY coarse size shows highest Modulus indicating that the sample became stiffer and more rigid. The increasing of stiffness and rigidity of PP/CY composites as CY content increased has reduced the flexibility. Therefore, the elongation at break of the composites decreased. The tensile fractured surface of composites was evaluated using SEM analysis. SEM micrographs show that the low CY content, particularly CY fine size was well bonded in PP matrix in contrast to high CY content, particularly CY coarse size.

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Sawdust Flour Reinforced Epoxidized Natural Rubber: Effect Of Trans-Polyoctylene Rubber on Curing Characteristics and Tensile Properties

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Journal of Physics: Conference Series 2018年第1期1019卷

作者： Omar S Dahham N Z Noriman R Hamzah S Z Syed Idrus Z Shayfull T Adam H Jaya Center of Excellence Geopolymer and Green Technology (CEGeoGTech) Faculty of Engineering Technology (FETech) Universiti Malaysia Perlis (UniMAP) Level 1 Block S2 UniCITI Alam Campus Sungai Chucuh Padang Besar 02100 Perlis Malaysia. School of Human Development and Techno-communication (iKOM) Green Advanced Computing and Technology (GREAT) Research Group – CEGeoGTech Universiti Malaysia Perlis (UniMAP School of Manufacturing Engineering Universiti Malaysia Perlis Arau 02600 Malaysia Green Design and Manufacture Research Group Center of Excellence Geopolymer and Green Technology (CEGeoGTech) Universiti Malaysia Perlis Kangar 0100 Malaysia Institute of Nano Electronic Engineering (INEE) Universiti Malaysia Perlis (UniMAP) 01000 Kangar Perlis Malaysia

In this work, the compatibilization effect of trans-polyoctylene rubber (TOR) on the cure characteristics, tensile properties and morphology of epoxidized natural rubber / sawdust flour (ENR-25/SD) compounds was evaluated. Five different TOR content (2, 4, 6, 8 and 10 phr) was used. Results showed that the increasing of TOR content caused decreasing on scorch and cure time. Moreover, the maximum torque has improved. The minimum torque showed decreasing as TOR content increased indicating that the rubber compound became less viscos and easy to process. The addition of TOR, particularly high TOR content (10 phr) into rubber compounds has increased the interfacial adhesion between SD and ENR-25, which in turn improved the tensile strength and modulus of the rubber compounds. The elongation at break has decreased as TOR content increased indicating that the samples became less flexible. SEM micrographs proved that the high TOR content presented stronger SD/ENR-25 than low TOR content.

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The Effects of Different Rice Husk Loading and Size on The Properties of Standard Malaysian Rubber / Rice Husk Composites

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Journal of Physics: Conference Series 2018年第1期1019卷

作者： Omar S Dahham N Z Noriman R Hamzah S Z Syed Idrus Z Shayfull T Adam N R Munirah Center of Excellence Geopolymer and Green Technology (CEGeoGTech) Faculty of Engineering Technology (FETech) Universiti Malaysia Perlis (UniMAP) Level 1 Block S2 UniCITI Alam Campus Sungai Chucuh Padang Besar 02100 Perlis Malaysia. School of Human Development and Techno-communication (iKOM) Green Advanced Computing and Technology (GREAT) Research Group – CEGeoGTech Universiti Malaysia Perlis (UniMAP School of Manufacturing Engineering Universiti Malaysia Perlis Arau 02600 Malaysia Green Design and Manufacture Research Group Center of Excellence Geopolymer and Green Technology (CEGeoGTech) Universiti Malaysia Perlis Kangar 0100 Malaysia Institute of Nano Electronic Engineering (INEE) Universiti Malaysia Perlis (UniMAP) 01000 Kangar Perlis Malaysia

This research is focused on the rice husk (RH) that acts as natural filler in Standard Malaysian Rubber (SMR L). Two ranges of RH size were prepared, coarser size at 10-20 mm and fine size at 150-300 μm. While the RH loading was (10,20,30,40 and 50 Phr). The effects of RH on the tensile properties, physical properties and cure characteristics of the compounds were examined. The results shown that the increasing of rice husk loading in SMR L/RH composites led to decrease in the cure (t90) and scorch time (t2) and increase in the minimum torque (ML) and maximum torque (MH). Despite the values of tensile strength decreased as RH content increase, the physical properties, such as hardness and crosslink density of the composites, particularly the composite with fine size filler were improved due to good filler-rubber interaction than coarser size filler.

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The Influences of Zirconium Dioxide on ENR-25/ZrO2 Composites: FTIR and TGA Analysis

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Journal of Physics: Conference Series 2018年第1期1019卷

作者： Omar S Dahham R Hamzah N Z Noriman A M Alakrach S Z Syed Idrus Z Shayfull T Adam Center of Excellence Geopolymer and Green Technology (CEGeoGTech) Faculty of Engineering Technology (FETech) Universiti Malaysia Perlis (UniMAP) Level 1 Block S2 UniCITI Alam Campus Sungai Chucuh Padang Besar 02100 Perlis Malaysia. School of Human Development and Techno-communication (iKOM) Green Advanced Computing and Technology (GREAT) Research Group – CEGeoGTech Universiti Malaysia Perlis (UniMAP School of Manufacturing Engineering Universiti Malaysia Perlis Arau 02600 Malaysia Green Design and Manufacture Research Group Center of Excellence Geopolymer and Green Technology (CEGeoGTech) Universiti Malaysia Perlis Kangar 0100 Malaysia Institute of Nano Electronic Engineering (INEE) Universiti Malaysia Perlis (UniMAP) 01000 Kangar Perlis Malaysia

The characterization and thermal stability of purified epoxidized natural rubber with 25 mol% epoxidation (ENR-25) and treated epoxidized natural rubber with 25 mol% epoxidation / Zirconium dioxide (ENR-25/ZrO2) Composites were studied using Fourier transform infrared spectroscopy (FTIR) and thermo gravimetric analysis (TGA). The ENR-25/ZrO2 composites were treated with acetic acid and two different loading (50 and 100 mg) of ZrO2 were used to form the composites. FTIR results show the ester (C-O) peaks at 1000-1300 cm-1 due to the presence of acetic acid in the composites. The disappearance of epoxide peak at range 880-875 cm-1 indicated that ZrO2 have formed hybrid bonds with opened epoxide rings. The both ENR/ZrO2 composites showed 2 major thermal degradation steps (304 - 489°C and 493 – 551°C) for 50 mg ZrO2 loading and (306 - 497°C 512 – 581°C) for 100 mg ZrO2 loading indicating that the thermal stability of the composites have improved.

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Slow Release Material from Epoxidized Natural Rubber and Rice Husk Composites for Agriculture Applications

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Journal of Physics: Conference Series 2018年第1期1019卷

作者： Marwa N Al-Samarrai R Hamzah S T Sam N Z Noriman Omar S Dahham S Z Syed Idrus T Adam Center of Excellence Geopolymer and Green Technology (CEGeoGTech) Faculty of Engineering Technology (FETech) Universiti Malaysia Perlis (UniMAP) Level 1 Block S2 UniCITI Alam Campus Sungai Chucuh Padang Besar 02100 Perlis Malaysia. School of Bioprocess Engineering Universiti Malaysia Perlis (UniMAP) Kompleks Pengajian Jejawi 3 02600 Arau Perlis Malaysia. School of Human Development and Techno-communication (iKOM) Green Advanced Computing and Technology (GREAT) Research Group – CEGeoGTech Universiti Malaysia Perlis (UniMAP Institute of Nano Electronic Engineering (INEE) Universiti Malaysia Perlis (UniMAP) 01000 Kangar Perlis Malaysia

This synthesis and characterization of slow release material from epoxidized natural rubber (ENR) and rice husks (RH) composites was conducted. The alkali modification of rice husks was carried using different NaOH concentration. ENR-50 and RH composites were analyzed by FTIR. Furthermore, the release behavior of the composites was invistigated using UV-visible spectroscopy. From the purified ENR-50, it can be characterized the peak epoxide group identified at 875 cm-1 and for the isoprene at 835 cm-1. For RH/urea beads, the CH2 peak of cellulose was obtained at 1457 cm-1. However, the CH2 is overlapped with cellulose at 1741 cm-1 and 1726 cm-1 that resulted for the partial opening of epoxide ring from carbonyl peak for hemi-cellulose and lignin, there are C=C stretching from aromatic group can be obtained at 1512 cm-1 and 1595 cm-1. The release of the composite at 7% NaOH concentration was higher than the composite at 1% NaOH concentration.

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Dynaldroid: A system for automated dynamic analysis of Android applications

Dynaldroid: A system for automated dynamic analysis of Andro...

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National Conference on Recent Advances in Electronics & Computer Engineering (RAECE)

作者： K.P Reddy Babu Rajesh V Himanshu Pareek Mahesh U Patil Center for Development of Advanced Computing (CDAC) Hyderabad India

ISBN: (纸本)9781509021772

Android is an extensively used mobile platform and with evolution it has also witnessed an increased influx of malicious applications in its market place. Availability of multiple sources for downloading applications has aided the malware developers by increasing the consumer base for their applications. This has caused users falling victim to malicious applications. A major hindrance in blocking the entry of malicious applications into the Android market place is scarcity of effective mechanisms to detect malicious applications. Static analysis of an Android application gives a good idea as to what the application is capable of, but it's effectiveness decreases if the application is obfuscated. Dynamic analysis of an Android application shows the true behavior of the application during execution. Thus dynamic analysis is more useful in uncovering the threats that the user has from an application. The contribution of this work includes automation of Android application execution on an emulator to facilitate dynamic analysis of the application. Based on information collected during dynamic analysis of malware samples, we derived a set of patterns which indicate the occurrence of malicious activity. These patterns allowed us to develop `Dynanlroid', a dynamic analysis tool for detecting a set of malicious actions performed by Android applications. The network activity carried out by the application is also analyzed by the Dynaldroid.

关键词： Cryptography Androids Humanoid robots Layout Semantics Performance evaluation

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Study of dimension reduction methodologies in data mining

Study of dimension reduction methodologies in data mining

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International Conference on computing, Communication & Automation (ICCCA)

作者： Nitika Sharma Kriti Saroha School of IT Center for Development of Advanced Computing Noida India

ISBN: (纸本)9781479988914

The data mining applications such as bioinformatics, risk management, forensics etc., involves very high dimensional dataset. Due to large number of dimensions, a well known problem of “Curse of Dimensionality” occurs. This problem leads to lower accuracy of machine learning classifiers due to involvement of many insignificant and irrelevant dimensions or features in the dataset. There are many methodologies that are being used to find the Critical Dimensions for a dataset that significantly reduces the number of dimensions. These feature reduction and subset selection methods reduce feature set, that eventually results in high classification accuracy and lower computation cost of machine learning algorithms. This paper surveys the schemes that are majorly used for Dimensionality Reduction mainly focusing Bioinformatics, Agricultural, Gene and Protein Expression datasets. A comparative analysis of surveyed methodologies is also done, based on which, best methodology for a certain type of dataset can be chosen.

关键词： Clustering algorithms Accuracy Principal component analysis Classification algorithms Algorithm design and analysis Data mining Machine learning algorithms

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All-sky search for continuous gravitational waves from isolated neutron stars using advanced LIGO and advanced Virgo O3 data

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Physical Review D 2022年第10期106卷 102008-102008页

作者： R. Abbott H. Abe F. Acernese K. Ackley N. Adhikari R. X. Adhikari V. K. Adkins V. B. Adya C. Affeldt D. Agarwal M. Agathos K. Agatsuma N. Aggarwal O. D. Aguiar L. Aiello A. Ain P. Ajith T. Akutsu S. Albanesi R. A. Alfaidi A. Allocca P. A. Altin A. Amato C. Anand S. Anand A. Ananyeva S. B. Anderson W. G. Anderson M. Ando T. Andrade N. Andres M. Andrés-Carcasona T. Andrić S. V. Angelova S. Ansoldi J. M. Antelis S. Antier T. Apostolatos E. Z. Appavuravther S. Appert S. K. Apple K. Arai A. Araya M. C. Araya J. S. Areeda M. Arène N. Aritomi N. Arnaud M. Arogeti S. M. Aronson H. Asada Y. Asali G. Ashton Y. Aso M. Assiduo S. Assis de Souza Melo S. M. Aston P. Astone F. Aubin K. AultONeal C. Austin S. Babak F. Badaracco M. K. M. Bader C. Badger S. Bae Y. Bae A. M. Baer S. Bagnasco Y. Bai J. Baird R. Bajpai T. Baka M. Ball G. Ballardin S. W. Ballmer A. Balsamo G. Baltus S. Banagiri B. Banerjee D. Bankar J. C. Barayoga C. Barbieri B. C. Barish D. Barker P. Barneo F. Barone B. Barr L. Barsotti M. Barsuglia D. Barta J. Bartlett M. A. Barton I. Bartos S. Basak R. Bassiri A. Basti M. Bawaj J. C. Bayley M. Bazzan B. R. Becher B. Bécsy V. M. Bedakihale F. Beirnaert M. Bejger I. Belahcene V. Benedetto D. Beniwal M. G. Benjamin T. F. Bennett J. D. Bentley M. BenYaala S. Bera M. Berbel F. Bergamin B. K. Berger S. Bernuzzi D. Bersanetti A. Bertolini J. Betzwieser D. Beveridge R. Bhandare A. V. Bhandari U. Bhardwaj R. Bhatt D. Bhattacharjee S. Bhaumik A. Bianchi I. A. Bilenko G. Billingsley S. Bini R. Birney O. Birnholtz S. Biscans M. Bischi S. Biscoveanu A. Bisht B. Biswas M. Bitossi M.-A. Bizouard J. K. Blackburn C. D. Blair D. G. Blair R. M. Blair F. Bobba N. Bode M. Boër G. Bogaert M. Boldrini G. N. Bolingbroke L. D. Bonavena F. Bondu E. Bonilla R. Bonnand P. Booker B. A. Boom R. Bork V. Boschi N. Bose S. Bose V. Bossilkov V. Boudart Y. Bouffanais A. Bozzi C. Bradaschia P. R. Brady A. Bramley A. Branch M. Branchesi J. E. Brau M. Breschi T. Briant J. H. Briggs A. Brillet M. Brinkmann P. Brockill A. F. Brooks J. Brooks D. D. Brown LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Graduate School of Science Tokyo Institute of Technology Meguro-ku Tokyo 152-8551 Japan Dipartimento di Farmacia Università di Salerno I-84084 Fisciano Salerno Italy INFN Sezione di Napoli Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy OzGrav School of Physics and Astronomy Monash University Clayton 3800 Victoria Australia University of Wisconsin-Milwaukee Milwaukee Wisconsin 53201 USA Louisiana State University Baton Rouge Louisiana 70803 USA OzGrav Australian National University Canberra Australian Capital Territory 0200 Australia Max Planck Institute for Gravitational Physics (Albert Einstein Institute) D-30167 Hannover Germany Leibniz Universität Hannover D-30167 Hannover Germany Inter-University Centre for Astronomy and Astrophysics Pune 411007 India University of Cambridge Cambridge CB2 1TN United Kingdom Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena D-07743 Jena Germany University of Birmingham Birmingham B15 2TT United Kingdom Northwestern University Evanston Illinois 60208 USA Instituto Nacional de Pesquisas Espaciais 12227-010 São José dos Campos São Paulo Brazil Cardiff University Cardiff CF24 3AA United Kingdom INFN Sezione di Pisa I-56127 Pisa Italy International Centre for Theoretical Sciences Tata Institute of Fundamental Research Bengaluru 560089 India Gravitational Wave Science Project National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Advanced Technology Center National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Dipartimento di Fisica Università degli Studi di Torino I-10125 Torino Italy INFN Sezione di Torino I-10125 Torino Italy SUPA University of Glasgow Glasgow G12 8QQ United Kingdom Università di Napoli “Federico II ” Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy Université de Lyon Université Claude Bernard Lyon 1

We present results of an all-sky search for continuous gravitational waves which can be produced by spinning neutron stars with an asymmetry around their rotation axis, using data from the third observing run of the advanced LIGO and advanced Virgo detectors. Four different analysis methods are used to search in a gravitational-wave frequency band from 10 to 2048 Hz and a first frequency derivative from −10−8 to 10−9 Hz/s. No statistically significant periodic gravitational-wave signal is observed by any of the four searches. As a result, upper limits on the gravitational-wave strain amplitude h0 are calculated. The best upper limits are obtained in the frequency range of 100 to 200 Hz and they are ∼1.1×10−25 at 95% confidence level. The minimum upper limit of 1.10×10−25 is achieved at a frequency 111.5 Hz. We also place constraints on the rates and abundances of nearby planetary- and asteroid-mass primordial black holes that could give rise to continuous gravitational-wave signals.

关键词： Gravitational wave sources Neutron stars & pulsars Gravitational wave detection

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All-sky search for gravitational wave emission from scalar boson clouds around spinning black holes in LIGO O3 data

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Physical Review D 2022年第10期105卷 102001-102001页

作者： R. Abbott H. Abe F. Acernese K. Ackley N. Adhikari R. X. Adhikari V. K. Adkins V. B. Adya C. Affeldt D. Agarwal M. Agathos K. Agatsuma N. Aggarwal O. D. Aguiar L. Aiello A. Ain P. Ajith T. Akutsu S. Albanesi R. A. Alfaidi A. Allocca P. A. Altin A. Amato C. Anand S. Anand A. Ananyeva S. B. Anderson W. G. Anderson M. Ando T. Andrade N. Andres M. Andrés-Carcasona T. Andrić S. V. Angelova S. Ansoldi J. M. Antelis S. Antier T. Apostolatos E. Z. Appavuravther S. Appert S. K. Apple K. Arai A. Araya M. C. Araya J. S. Areeda M. Arène N. Aritomi N. Arnaud M. Arogeti S. M. Aronson K. G. Arun H. Asada Y. Asali G. Ashton Y. Aso M. Assiduo S. Assis de Souza Melo S. M. Aston P. Astone F. Aubin K. AultONeal C. Austin S. Babak F. Badaracco M. K. M. Bader C. Badger S. Bae Y. Bae A. M. Baer S. Bagnasco Y. Bai J. Baird R. Bajpai T. Baka M. Ball G. Ballardin S. W. Ballmer A. Balsamo G. Baltus S. Banagiri B. Banerjee D. Bankar J. C. Barayoga C. Barbieri B. C. Barish D. Barker P. Barneo F. Barone B. Barr L. Barsotti M. Barsuglia D. Barta J. Bartlett M. A. Barton I. Bartos S. Basak R. Bassiri A. Basti M. Bawaj J. C. Bayley M. Bazzan B. R. Becher B. Bécsy V. M. Bedakihale F. Beirnaert M. Bejger I. Belahcene V. Benedetto D. Beniwal M. G. Benjamin T. F. Bennett J. D. Bentley M. BenYaala S. Bera M. Berbel F. Bergamin B. K. Berger S. Bernuzzi D. Bersanetti A. Bertolini J. Betzwieser D. Beveridge R. Bhandare A. V. Bhandari U. Bhardwaj R. Bhatt D. Bhattacharjee S. Bhaumik A. Bianchi I. A. Bilenko G. Billingsley S. Bini R. Birney O. Birnholtz S. Biscans M. Bischi S. Biscoveanu A. Bisht B. Biswas M. Bitossi M.-A. Bizouard J. K. Blackburn C. D. Blair D. G. Blair R. M. Blair F. Bobba N. Bode M. Boër G. Bogaert M. Boldrini G. N. Bolingbroke L. D. Bonavena F. Bondu E. Bonilla R. Bonnand P. Booker B. A. Boom R. Bork V. Boschi N. Bose S. Bose V. Bossilkov V. Boudart Y. Bouffanais A. Bozzi C. Bradaschia P. R. Brady A. Bramley A. Branch M. Branchesi J. E. Brau M. Breschi T. Briant J. H. Briggs A. Brillet M. Brinkmann P. Brockill A. F. Brooks J. Brooks D LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Graduate School of Science Tokyo Institute of Technology Meguro-ku Tokyo 152-8551 Japan Dipartimento di Farmacia Università di Salerno I-84084 Fisciano Salerno Italy INFN Sezione di Napoli Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy OzGrav School of Physics and Astronomy Monash University Clayton 3800 Victoria Australia University of Wisconsin-Milwaukee Milwaukee Wisconsin 53201 USA Louisiana State University Baton Rouge Louisiana 70803 USA OzGrav Australian National University Canberra Australian Capital Territory 0200 Australia Max Planck Institute for Gravitational Physics (Albert Einstein Institute) D-30167 Hannover Germany Leibniz Universität Hannover D-30167 Hannover Germany Inter-University Centre for Astronomy and Astrophysics Pune 411007 India University of Cambridge Cambridge CB2 1TN United Kingdom Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena D-07743 Jena Germany University of Birmingham Birmingham B15 2TT United Kingdom Northwestern University Evanston Illinois 60208 USA Instituto Nacional de Pesquisas Espaciais 12227-010 São José dos Campos São Paulo Brazil Cardiff University Cardiff CF24 3AA United Kingdom INFN Sezione di Pisa I-56127 Pisa Italy International Centre for Theoretical Sciences Tata Institute of Fundamental Research Bengaluru 560089 India Gravitational Wave Science Project National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Advanced Technology Center National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Dipartimento di Fisica Università degli Studi di Torino I-10125 Torino Italy INFN Sezione di Torino I-10125 Torino Italy SUPA University of Glasgow Glasgow G12 8QQ United Kingdom Università di Napoli “Federico II” Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy Université de Lyon Université Claude Bernard Lyon 1

This paper describes the first all-sky search for long-duration, quasimonochromatic gravitational-wave signals emitted by ultralight scalar boson clouds around spinning black holes using data from the third observing run of advanced LIGO. We analyze the frequency range from 20 to 610 Hz, over a small frequency derivative range around zero, and use multiple frequency resolutions to be robust towards possible signal frequency wanderings. Outliers from this search are followed up using two different methods, one more suitable for nearly monochromatic signals, and the other more robust towards frequency fluctuations. We do not find any evidence for such signals and set upper limits on the signal strain amplitude, the most stringent being ≈10−25 at around 130 Hz. We interpret these upper limits as both an “exclusion region” in the boson mass/black hole mass plane and the maximum detectable distance for a given boson mass, based on an assumption of the age of the black hole/boson cloud system.

关键词： Classical black holes Gravitational wave detection Gravitational wave sources Particle astrophysics Particle dark matter

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Search for gravitational waves from Scorpius X-1 with a hidden Markov model in O3 LIGO data

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Physical Review D 2022年第6期106卷 062002-062002页

Results are presented for a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to allow for spin wandering. This search improves on previous HMM-based searches of Laser Interferometer Gravitational-Wave Observatory data by including the orbital period in the search template grid, and by analyzing data from the latest (third) observing run. In the frequency range searched, from 60 to 500 Hz, we find no evidence of gravitational radiation. This is the most sensitive search for Scorpius X-1 using a HMM to date. For the most sensitive subband, starting at 256.06 Hz, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=6.16×10−26, assuming the orbital inclination angle takes its electromagnetically restricted value ι=44°. The upper limits on gravitational wave strain reported here are on average a factor of ∼3 lower than in the second observing run HMM search. This is the first Scorpius X-1 HMM search with upper limits that reach below the indirect torque-balance limit for certain subbands, assuming ι=44°.

关键词： Gravitational waves Binary stars Neutron stars & pulsars

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