scholarly journals Acoustic instrumentation for a bubble chamber towards dark matter searches

2019 ◽  
Vol 88 ◽  
pp. 01002
Author(s):  
M. Reis ◽  
M. Felizardo ◽  
A. C. Fernandes ◽  
A. Kling ◽  
T. Morlat ◽  
...  

Dark matter is one of the top unsolved mysteries in physics. Its existence is well-established although its nature remains unknown. Despite the progress made in the direct search effort, reflecting over 10 orders of magnitude in sensitivity since 1984, no true candidates to explain this phenomenon have appeared in searches covering a range from ~10 GeV to 1 TeV. This article reports on the development of a 1 kg freon bubble chamber prototype, including the chamber recompression system design and testing, initial acoustic detection of bubble formation, and initial neutron and alpha detector response studies. The prototype constructed was a transparent acrylic containment vessel, capable of withstanding recompression cycles to a pressure of 16 bar. The acoustic signal accompanying bubble formation was investigated using three different sensors: a low frequency microphone (Panasonic) with a flat response over 0.020-16 kHz, an ultrasound externallypolarized condenser microphone (AviSoft) with a flat response over 10-150 kHz, and an hydrophone (Reson) with a flat response over 5-170 kHz. Acoustic signatures of several induced events were successfully registered. The data acquisition digitizer used, to meet the range of the three microphones, was the NI PCI-6251 16-Bit, with at least 1.25 MSps for 1-Channel.

Author(s):  
Xiongliang Yao ◽  
Xianghong Huang ◽  
Zeyu Shi ◽  
Wei Xiao ◽  
Kainan Huang

When a research ship sails at a high speed, there is relative motion between the ship and fluid. The ship is slammed by the fluid. To reduce the direct impact of the fluid, sonar is installed in the moonpool, and acoustic detection equipment is installed along the research ship bottom behind the moonpool. However, during high-speed sailing, a large number of bubbles form in the moonpool. Some bubbles escape from the moonpool and flow backward along the bottom of the ship. When a large number of bubbles are around the sonar and acoustic detection equipment, the equipment malfunctions. However, there have been few studies on bubble formation in the moonpool with sonar and distribution along the ship bottom behind the moonpool. Therefore, a related model was developed and prototype tests were carried out in this study. The appropriate similarity criteria were selected and verified to ensure the reliability of the experiment. Considering the influences of speed, sonar, moonpool shape, and draft, the reason and mechanism of bubble formation in a sonar moonpool were studied. An artificial ventilation method was used to simulate a real navigation environment. Because the bubbles are in a bright state under laser irradiation, the bubbles can be used as tracer particles. A high-speed camera captured illuminated bubbles. The distribution mechanism of bubbles along the ship bottom behind the moonpool was investigated using particle image velocimetry under the influence of the moonpool shape and sailing speed. The model experimental results agreed well with those of the prototype test. The air sucked into the water was the dominant factor in bubble formation in the moonpool. The bubbles were distributed in a W shape under the ship bottom.


2010 ◽  
Author(s):  
Peter S. Cooper ◽  
J. C. D’Olivo ◽  
A. Frank ◽  
R. Lopez-Fernandez ◽  
M. A. Perez
Keyword(s):  

Author(s):  
Syaiful Anwar ◽  
Muhamad Taufiq Tamam ◽  
Itmi Hidayat Kurniawan

Seiring perkembangan jaman, saat ini energi listrik telah menjadi salah satu kebutuhan primer dalam kehidupan sehari-hari, baik untuk melakukan pekerjaan ataupun kegiatan yang lainnya. Pembangkit Listrik Tenaga Air atau PLTA dengan menggunakan konsep hydrocat merupakan sebuah konsep pembangkit listrik yang diciptakan untuk aliran jalur irigasi yang memiliki ukuran tidak terlalu besar dan tingkat kedalamannya yang rendah. Oleh karena itu dibuatlah rancang bangun sistem pembangkit listrik menggunakan konsep hydrocat. Pada penelitian ini menggunakan generator DC sebagai sumber tenaga listrik dan menggunakan jenis turbin undershot. Penelitian ini dilakukan di Desa Karang Cegak Kecamatan Kutasari Kabupaten Purbalingga. Beban pada penelitian ini menggunakan lampu LED SMD 1,2 Watt, 2,4 Watt 3,6 Watt, dan 4,8 Watt. Alat ini mampu menghasilkan putaran pulley turbin air sebesar 69,2 rpm, 60,8 rpm, 59,0 rpm, 58,7 rpm, 57,1 rpm, dan 56,7 rpm. Putaran pulley generator DC sebesar 595,9 rpm, 586,1 rpm, 520,1 rpm, 506,2 rpm, dan 496,0 rpm. Besar tegangan yang dihasilkan 31,86 Volt, 9,20 Volt, 8,61 Volt, 8,38 Volt, dan 8,25 Volt. Besar arus yang dihasilkan sebesar 0,02 Ampere, dan besar daya yang dihasilkan sebesar 0,1836 Watt, 0,1718 Watt, 0,1671 Watt, dan 0,165 Watt.Along with the development of the times, nowadays electrical energy has become one of the primary needs in everyday life, both for doing work or other activities. Hydroelectric Power or Hydroelectric Power using the hydrocat concept is a power generation concept created for irrigation channel flow that is not too large and has a low depth level. Therefore, a power plant system design using the hydrocat concept was made. In this study using a DC generator as a source of electricity and using a type of undershot turbine. This research was conducted in Karang Cegak Village, Kutasari District, Purbalingga Regency. The load in this study uses 1.2 Watt SMD LED lamps, 2.4 Watt 3.6 Watt, and 4.8 Watt. This tool is capable of producing water turbine pulley rotation of 69.2 rpm, 60.8 rpm, 59.0 rpm, 58.7 rpm, 57.1 rpm, and 56.7 rpm. DC generator pulley rotation of 595.9 rpm, 586.1 rpm, 520.1 rpm, 506.2 rpm, and 496.0 rpm. The resulting voltages are 31.86 Volts, 9.20 Volts, 8.61 Volts, 8.38 Volts, and 8.25 Volts. The amount of current generated is 0.02 Ampere, and the amount of power generated is 0.1836 Watt, 0.1718 Watt, 0.1671 Watt, and 0.165 Watt.


2017 ◽  
Vol 118 (25) ◽  
Author(s):  
C. Amole ◽  
M. Ardid ◽  
I. J. Arnquist ◽  
D. M. Asner ◽  
D. Baxter ◽  
...  

Author(s):  
I. S. Pearsall

The onset of cavitation in a hydraulic machine can be determined visually and its effect on performance by performance tests. It would be convenient to have an alternative method that required neither transparent sections nor expensive tests. Initial tests have been made measuring noise over a frequency range of 20 c/s-20 kc/s in one-third octave bands, on a number of pumps and turbines. An accelerometer attached to the casing was used. The tests indicated that, generally, the onset of cavitation was accompanied by a rise in the high-frequency noise, whilst the low-frequency noise increased as the cavitation developed. A maximum of cavitation noise was reached before the efficiency and load fell off. In some cases difficulty was experienced because blade cavitation was drowned by noise caused by other cavitation, such as the vortex in a Francis turbine. It also appears that the noise following the onset of cavitation is at the frequency which is used as a critical frequency in accelerated erosion tests. Further development of techniques is required, but the initial tests are encouraging.


2018 ◽  
Vol 23 (3) ◽  
pp. 254-265 ◽  
Author(s):  
Syed Furqan Rafique ◽  
Jianhua Zhang ◽  
Muhammad Hanan ◽  
Waseem Aslam ◽  
Atiq Ur Rehman ◽  
...  

Designs ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 40
Author(s):  
Alessandro Pracucci ◽  
Sara Magnani ◽  
Oscar Casadei

The European Commission has identified the building industry as one of the key sectors to achieve its 2020 strategy to create conditions for smart, sustainable, and inclusive growth. In this frame, the aim of Horizon 2020′s Eensulate project is the development of innovative lightweight and highly insulating energy efficient unitized building façades, suitable for both new and existing buildings. The Eensulate façade module integrates two components developed within the project: Vacuum Insulated Glass (VIG) for architectural purposes, with a U-value of 0.3 W/sqm∙K; a highly insulating foam for automated manufacturing and insulation for the spandrel part. This article presents the Eensulate façade system design simulations and achievements related to VIG integration to solve issues that emerged by the utilization of its innovative components (sealant thermal bridge and getter strips). VIG design and testing have gradually changed the façade module and consequently, façade components have been progressively designed to achieve the expected target of 0.641 W/sqm∙K for thermal transmittance. The results demonstrate that the target can be achieved by aluminum profiles, Ethylene Propylene Diene Monomer (EPDM) thermal bridge, and additional insulating components, obtaining a new product for unitized façades able to reduce energy consumption in buildings with large glass surfaces.


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