scholarly journals Monoblock silencers for pistols

2020 ◽  
Vol 2020 (3) ◽  
pp. 3-11
Author(s):  
O.V. Pylypenkо ◽  
◽  
N.A. Konovalov ◽  
V.I. Kovalenko ◽  
D.V. Semenchuk ◽  
...  
Keyword(s):  
Sound Level ◽  
The Body ◽  
Operating Efficiency ◽  
National Academy Of Sciences ◽  
Space Agency ◽  
Firing Range ◽  
Shooting Gallery ◽  
Level Meter ◽  
Full Scale Tests ◽  
Production Company

This paper presents the stages of development of silencers with monoblock spreaders for pistols. The features of two groups of monoblock silencer designs (with and without a central tube) are identified and described. The use of different materials for different silencer parts is substantiated: the body and the monoblock are made of an aluminium alloy, the covers and the unions are made of a titanium alloy, and the perforated tubes are made of steel or titanium. The paper shows the features of design solutions and describes the design of internal components and their effect on the operating efficiency for different embodiments of theirs. The mamufacture of silencers of this design is less labor intensive in comparison with silences with discrete components (bodies, bushings, etc.), thus offering a lower cost due to the use of advanced technologies in the manufacturing of the silencer components and the silencer as a whole. The paper presents the results of firing range and shooting gallery full-scale tests of monoblock silencers with Glock 17 and Fort 14 pistols using 9х18 mm і 9х19 mm cartridges. The results show that: - in sound suppression efficiency, the silencers compare well with their best foreign counterparts and outperform the standard silencers of Research and Production Company Fort at comparable dimensions and mass. The efficiency of the silencers developed was measured with a precision pulsed sound level meter and verified by comparison tests with basic prototypes developed earlier and foreign silencers. The efficiency proved to be (25 – 36) dB(A). - the silencers do not affect pistol automatics and sustain standard firing regimes, - the silencers do not affect the shot grouping characteristics, and - the silencers do not affect other performance characteristics either. Hence the silencers for Fort or similar pistols developed at the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine are efficient and reliable.

scholarly journals Small-size silencers for stub-barreled arms

2020 ◽  
Vol 2020 (4) ◽  
pp. 3-12
Author(s):  
O.V. Pylypenkо ◽  
◽  
N.A. Konovalov ◽  
V.I. Kovalenko ◽  
D.V. Semenchuk ◽  
...  
Keyword(s):  
Sound Level ◽  
Operating Efficiency ◽  
National Academy Of Sciences ◽  
Small Arms ◽  
Space Agency ◽  
Level Meter ◽  
Full Scale Tests ◽  
Enclosed Space ◽  
Academy Of Sciences ◽  
Sound Suppression

This paper describes the designs and manufacturing and testing features of small-size silencers developed at the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine for arms used in enclosed space. The topicality of the development is due to the use of stub-barreled arms by Ukrainian special subunits. With consideration for the features of existing silencers for submachine guns of special subunits, a line of compact silencer development was chosen. The paper formulates requirements for the design of silencers for stub-barreled small arms and material and manufacturing accuracy requirements for their components. The use of silent stub-barreled small arms in enclosed space without damaging the shooter’s organs of hearing is justified. In combat operations, sound suppression allows subunits to contact with one another and their commanders to have the situation under control. The paper shows the features of design solutions and describes the design of the silencers’ internal components and their effect on the operating efficiency for different embodiments of theirs. The paper presents the appearances, construction arrangements, and specifications of the small-size silencers developed and the results of their full-scale tests. The sound suppression efficiency of the silencers developed was measured with a sound level meter and verified by comparison tests with basic prototypes developed earlier. The efficiency proved to be (28 – 34) dBA, which is on a level with their best foreign counterparts. The test showed that: - the silencers do not affect firearm automatics and sustain standard firing regimes, - the silencers do not affect the shot grouping characteristics, and - the silencers do not affect other performance characteristics either. Hence the compact silencers developed for stub-barreled submachine guns (assault rifles) are efficient and reliable.

Measurement of Noise inside the Compartment and Vibration on both Sides of Elastomeric Powertrain Mounts of Passenger Car

2013 ◽  
Vol 471 ◽  
pp. 59-63
Author(s):  
Mohd Noor Arib Rejab ◽  
Roslan Abd Rahman ◽  
Raja Ishak Raja Hamzah ◽  
Jawaid Iqbal Inayat Hussain ◽  
Nazirah Ahmad ◽  
...  
Keyword(s):  
Fast Response ◽  
Sound Level ◽  
Measurement Noise ◽  
The Other ◽  
Vibration Level ◽  
Test Conditions ◽  
Exhaust Noise ◽  
Run Up ◽  
Level Meter ◽  
High Level

This paper presents an evaluation on elastomeric mount used to isolate vibration from powertrain to chassis or structure vehicle. The assessments started with measurement of noise inside compartment, and exhaust noise. This is followed by the measurement of vibration on both sides of elastomeric mounts. The noise in the compartment and exhaust noise is measured according to BS 6086: 1981 and BS ISO 5130: 2007. The noise in the compartment and vibration is tested in three conditions. Firstly, engine is run-up with load (driving at second gear); secondly, without load; and thirdly, without load but hanging. A microphone is fixed at the ear of the mannequin. The fast response and A weighting sound level meter were used for measurement noise in the compartment and exhaust noise. The vibration is measured in terms of acceleration on both sides of each elastomeric powertrain mounts. Two accelerometer transducers are fixed on both sides of powertrain elastomeric mounts. One side was identified as a source of vibration and the other as receiver of vibrations. The results showed that the pattern of overall vibration level on source and receiver increased from 1050 RPM (idling) to 4000 RPM on all test conditions. Vibration transmitted to chassis or receiver structure was analyzed using transmissibility concept. By evaluating test condition of engine run-up without load, informed that the front and rear mounts showed a high level transmissibility contributing to structure-borne noise.

Testing of Sonic-Absorbent Panels’ Behavior in Open-Air Environment

2012 ◽  
Author(s):  
Petru A. Pop ◽  
Patricia A. Ungur ◽  
Liviu Lazar ◽  
Mircea Gordan ◽  
Florin M. Marcu
Keyword(s):  
High Frequency ◽  
Noise Pollution ◽  
Sound Level ◽  
Sound Level Meter ◽  
Data Logger ◽  
Public Buildings ◽  
Gypsum Plaster ◽  
Level Meter ◽  
And Control

One wildly used method to reduce and control the noise pollution in green city’s buildings is using sonic-absorbent panels. Their applications can be multiple, such as the insulation of buildings, acoustic barriers and fences along the highway or in front of supermarkets, hospitals and other public buildings. This paper presents a method for testing the behavior of sonic-absorbent panels in open-air environment. The work represents a carrying on of previous research about absorbent materials from gypsum family, tested in lab conditions. The experiment setup used a dynamic installation and as a sample a stand formed by six sonic-absorbent panels from special modeling alpha-gypsum plaster. This installation has been composed of two loudspeakers for emitting the sound at a well-defined frequency by the first laptop, the microphone for detecting and transmitting the signal to the second laptop for analyzing and processing the data. All operations were performed using MATLAB Programs, while a Data Logger Sound Level Meter type CENTER 332 was put on near the microphone to compare both results. The first experiment of acoustic stand has been realized by setting up the installation at a frequency from 50 Hz to 1250 Hz and altering the distance between loudspeakers and stand at 0.5m to 1m and 1.5m, respectively. The second experiment kept the same test’s conditions, while two and three layers of sonic-absorbent panels formed the stand, respectively, but at same distance from source of 0.5 m. In both tests, the results underlined the good sonic-absorbent properties of these panels, especially at medium and high frequency, which can recommend using the panels for multiple outside applications.

Pemetaan Dan Perhitungan Pemaparan Tingkat Kebisingan Pada Industri Pengolahan Kayu Di Kecamatan Siak, Provinsi Riau

2021 ◽  
Vol 6 (2) ◽  
pp. 68-76
Author(s):  
Aryo Sasmita ◽  
Muhammad Reza ◽  
Rodesia Mustika Rozi
Keyword(s):  
Sound Level ◽  
Sound Level Meter ◽  
Noise Mapping ◽  
Level Meter

Dalam kegiatan operasionalnya CV. X yang bergerak pada pengolahan kayu, berpotensi menimbulkan kebisingan yang berasal dari mesin-mesin yang digunakan dalam proses produksi pallet. Kebisingan di perusahaan ini dapat berpengaruh terhadap kesehatan dan kenyamanan pekerja. Penelitian ini bertujuan untuk mengetahui intensitas kebisingan yang dihasilkan oleh mesin produksi, lama waktu pemaparan, pemetaan kebisingan dan upaya pengendalian kebisingan. Metode pengukuran kebisingan mengacu pada metode noise mapping dan alat yang digunakan adalah Sound Level Meter. Data yang diperoleh kemudian diolah menjadi peta kontur dengan variasi warna biru, hijau, kuning, ungu dan merah. Hasil penelitian menunjukkan tingkat kebisingan tertinggi sebesar 99,4 dB dan tingkat kebisingan terendah sebesar 67,3 dB. Berdasarkan hasil perhitungan menggunakan persamaan NIOSH dari 128 titik pengukuran metode noise mapping terdapat 38 titik dengan tingkat kebisingan >85 dB yang menunjukkan waktu pemaparan di atas standar yang sudah direkomendasikan NIOSH. Tingkat kebisingan tertinggi sebesar 99,4 dB dengan lama pemaparan selama 0,3 jam dan tingkat kebisingan terendah sebesar 67,3 dB dengan lama pemaparan selama 475 jam. Upaya pengendalian yang dapat dilakukan untuk mengurangi kebisingan seperti pengendalian dari sumber, jalur transmisi, dan penerima.

A Sound Level Meter featured with automatic estimation of the measurement uncertainty

Measurement ◽  
2021 ◽  
pp. 110409
Author(s):  
Marco Carratù ◽  
Consolatina Liguori ◽  
Vincenzo Paciello ◽  
Antonio Pietrosanto ◽  
Domenico Russo ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Sound Level ◽  
Sound Level Meter ◽  
Automatic Estimation ◽  
Level Meter

scholarly journals Investigation of Flow Behavior around Corotating Blades in a Double-Spindle Lawn Mower Deck

2005 ◽  
Vol 2005 (1) ◽  
pp. 77-89 ◽  
Author(s):  
W. Chon ◽  
R. S. Amano
Keyword(s):  
Flow Pattern ◽  
High Speed ◽  
Flow Behavior ◽  
Flow Analysis ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Video Camera ◽  
Sound Level ◽  
Lawn Mower ◽  
Level Meter

When the airflow patterns inside a lawn mower deck are understood, the deck can be redesigned to be efficient and have an increased cutting ability. To learn more, a combination of computational and experimental studies was performed to investigate the effects of blade and housing designs on a flow pattern inside a1.1mwide corotating double-spindle lawn mower deck with side discharge. For the experimental portion of the study, air velocities inside the deck were measured using a laser Doppler velocimetry (LDV) system. A high-speed video camera was used to observe the flow pattern. Furthermore, noise levels were measured using a sound level meter. For the computational fluid dynamics (CFD) work, several arbitrary radial sections of a two-dimensional blade were selected to study flow computations. A three-dimensional, full deck model was also developed for realistic flow analysis. The computational results were then compared with the experimental results.

Recognition for Spindle Speeds of Drill Press Based on Sound Signals Produced from Drilling

2008 ◽  
Vol 375-376 ◽  
pp. 535-538
Author(s):  
Xiang Feng Li ◽  
Gen Lian Yang ◽  
Dun Wen Zuo
Keyword(s):  
Wavelet Packet ◽  
Sound Level ◽  
Effective Characteristics ◽  
Frequency Bands ◽  
Training Samples ◽  
Bp Networks ◽  
Training Error ◽  
Effective Network ◽  
Level Meter ◽  
Drill Press

Effects of running state and spindle speeds on the sound signals produced from a drill press are investigated. And the obtained sound signals by using of a sound level meter are analyzed in both time domain and frequency domain. It is evident that there is more high frequency energy for drilling sound signals with load than without load. And spindle speeds still affect their energy distribution of drilling sound signals. Using wavelet decomposition and wavelet packet decomposition, drilling sound signals are decomposed into a number of frequency bands. And energy percentages of the divided frequency bands are extracted to be the effective characteristics to recognize spindle speeds. Meanwhile, training error of different BP networks is compared to obtain the effective network for recognition spindle speeds. By using of the obtained network structure named 16-30-5, the study rate for training samples and the recognize rate for testing samples are all above 95%.

S254 – Bone Conduction Noise Exposure via Ventilators in the NICU

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P160-P160
Author(s):  
Angela P Black ◽  
James D Sidman
Keyword(s):  
Ambient Noise ◽  
Noise Exposure ◽  
Bone Conduction ◽  
Sound Level ◽  
Noise Levels ◽  
High Noise ◽  
Endotracheal Tubes ◽  
Level Meter ◽  
Hearing Damage ◽  
Air Conduction

Objectives To demonstrate that neonatal ventilators produce high noise levels through bone conduction (BC) via endotracheal tubes, as well as air conduction (AC) from ambient noise. Methods A sound level meter was used to measure the noise levels 4 feet from the ventilator and in direct contact at the end of a balloon attached to the ETT to simulate the noise presented to the infant. 3 commonly used neonatal ventilators (Sensormedics 3100A, VIP Bird and Bunnell Jet) were examined. Results Noise levels were significantly higher (6 – 14 dB) at the end of the ETT than 4 ft from the ventilator for all ventilators studied. Conclusions Previous studies have shown high ambient noise levels in NICUs, but have failed to address the actual noise presented to the infant. ETT transmission of noise as a direct bone stimulus through the skull has been overlooked. This study has shown that high noise intensities are being presented not only as AC, but as BC to the infants though the ETT. This study demonstrates, therefore, that ear protection alone will not save these at-risk infants from hearing damage. More must be done to decrease noise exposure and develop quieter machines.

Noise Exposure Associated With Hearing Aid Use in Industry

1996 ◽  
Vol 39 (2) ◽  
pp. 251-260 ◽  
Author(s):  
Thomas G. Dolan ◽  
James F. Maurer
Keyword(s):  
Hearing Aids ◽  
Noise Exposure ◽  
Hearing Aid ◽  
Sound Field ◽  
High Gain ◽  
Sound Level ◽  
Weighted Averages ◽  
Hearing Aid Use ◽  
Listening Environments ◽  
Level Meter

Although noise may be innocuous in many vocational environments, there is a growing concern in industry that it can reach hazardous levels when amplified by hearing aids. This study examined the daily noise exposures associated with hearing aid use in industry. This was done by both laboratory and site measurements in which hearing aids were coupled to the microphone of an integrating sound level meter or dosimeter. The former method involved the use of recorded railroad and manufacturing noise and a Bruel and Kjaer 4128 Head and Torso simulator. In the latter procedure, a worker wore one of three hearing aids coupled to a dosimeter during 8-hour shifts in a manufacturing plant. Both methods demonstrated that even when amplified by mild-gain hearing aids, noise exposures rose from time-weighted averages near 80 dBA to well above the OSHA maximum of 90 dBA. The OSHA maximum was also exceeded when moderate and high gain instruments were worn in non-occupational listening environments. The results suggest that current OSHA regulations that limit noise exposure in sound field are inappropriate for hearing aid users.

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