• Title/Summary/Keyword: Velocity Level

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The Vibration Velocity and Vibration Level of Near-field Blasting Vibration in an Urban Blasting Site (근접장 발파진동에서 진동속도와 진동레벨의 비교)

  • Lee, Yeon-Soo;Chang, Seo-Il
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.8 s.101
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    • pp.918-923
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    • 2005
  • The vibration level (dB(V)) and vibration velocity (cm/sec) on the ground and buildings due to the differences of the measuring sites from the blasting source was investigated. To compare with vibration level and vibration velocity theirs magnitude was not surely directly proportional and vibration velocity 0.1 cm/sec was $45\~50$ dB(V). The difference between the measured vibration level and the calculated vibration level by Ejima's equation using vibration velocity PVS(peak vector sum) showed $21.0\~30.9$ dB(V) on the ground, $15.3\~23.6$ dB(V) on the apartment, respectively. And the correlation of vibration velocity and nitration level at the measuring sites of lower altitude showed higher than that of higher altitude.

A Study on the Prediction Method of Blasting Vibration (발파진동 예측방법에 관한 연구)

  • Lee, Yeon-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.361-365
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    • 2006
  • In order to predict method of blasting vibration in ground and it's resident located around blasting field in urban area, blasting vibration characteristics were measured the vibration velocity(cm/sec), vibration acceleration($cm/sec^2$), vibration acceleration level(dB) and vibration level(dB(V)). The charged powder were used to 1.25kg and measuring sites were 25 points front 4m to 90m at the ground. The correlation of vibration velocity, vibration acceleration, vibration acceleration level and vibration level by square root scaled distance and cube root scaled distance were investigated. The correlation of PPV(peak particle velocity) velocity by SRSD(square root scaled distance) and CRSD(cube root scaled distance) was 0.85 and 0.86 and the correlation of PVS(peak vector sum) velocity by SRSD and CRSD was 0.82. Also vibration acceleration, vibration acceleration level and vibration level by SRSD and CRSD was 0.61, 0.62 and 0.82, respectively. As results, the vibration velocity and vibration level(dB(V)) was showed good correlation, but the vibration acceleration and vibration acceleration level was not showed good correlation.

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The Vibration Velocity and Vibration Level of Near-field Blasting Vibration in an Urban Blasting Site (근접장 발파진동에서 진동속도와 진동레벨)

  • Lee, Yeon-Soo;Chang, Seo-Il
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.766-771
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    • 2005
  • To compare blasting vibration at blasting construction field in urban area, the vibration level (dB(V)) and vibration velocity (cm/sec) on the ground and the structure of buildings due to the differences of the measuring sites from the blasting source is investigated and the difference between the measured vertical vibration level and the calculated vibration level by using vibration velocity PVS and the correlation between vibration velocity and vibration level and is studied in the thesis.

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An Estimation Of Average Current Velocity In The Western Channel Of The Korea Strait From Mean Sea Level Data

  • Lee, Jae Chul;Jung, Chang Hee
    • 한국해양학회지
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    • v.12 no.2
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    • pp.67-74
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    • 1977
  • With the serial observation data and the tidal records at Busan and Izuhara from 1966 to 1973, the geostrophic current velocity and its relation to the difference of mean sea level of both sides were studied in order to estimate indirectly the average current velocity from the tidal observations. The results shows that the current velocity is estimated by the relationship V=4.016(H-98.3) with the 95% confidence limits of V 4.2 cm/sec. Ther relationship between the observed current velocity and the simultaneous daily mean sea level difference shows a similar result, V=4.717(H-99.6). The two equations were applied to the evaluation of annual variations of current velocity from the average monthly mean sea level data of both stations.

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A Study on the Related Equation of the Blast Vibration Velocity and the Vibration Level (발파진동속도와 진동레벨과의 관계식 연구)

  • Kim, Il-Jung;Ki, Kyoung-Chul;Cho, Young-Dong
    • Explosives and Blasting
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    • v.27 no.1
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    • pp.79-87
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    • 2009
  • The regression analysis of the ground vibration data (particle velocity and vibration level) was carried out to find an empirical relation between the vibration velocity (PVS, PPV, $V_V$) and the vibration level. The regression results revealed that the correlation of the blast vibration velocity and vibration level was quite good. It seems that the empirical relation obtained in this research will be applied to evaluating and managing the various environmental vibrations.

Hydrodynamic Characteristics in a Hexagonal Inverse Fluidized Bed (장방형 역유동층의 동력학적 특성)

  • 박영식;안갑환
    • Journal of Environmental Science International
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    • v.5 no.1
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    • pp.93-102
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    • 1996
  • Hydrodynamic characteristics such as gas holdup, liquid circulation velocity and bed expansion in a hexagonal inverse fluidized bed were investigated using air-water system by changing the ratio ($A_d$/$A_r$) of cross-sectional area between the riser and the downcomer, the liquid level($H_1$/H), and the superficial gas velocity($U_g$). The gas holdup and the liquid circulation velocity were steadily increased with the superficial gas velocity increasing, but at high superficial gas velocity, some of gas bubbles were carried over to a downcomer and circulated through the column. When the superficial gas velocity was high, the $A_d$/$A_r$ ratio in the range of 1 to 2.4 did not affect the liquid circulation velocity, but the maximum bed expansion was obtained at $A_d$/$A_r$ ratio of 1.25. The liquid circulation velocity was expressed as a model equation below with variables of the cross-sectional area ratio($A_d$/$A_r$) between riser to downcomer, the liquid level($H_1$/H), the superficial gas velocity($U_g$), the sparser height[(H-$H_s$)/H], and the draft Plate level($H_b$/H). $U_{ld}$ = 11.62U_g^{0.75}$${(\frac{H_1}{H})}^{10.30}$${(\frac{A_d}{A_r})}^{-0.52}$${(\frac({H-H_s}{H})}^{0.91}$${(\frac{H_b}{H})}^{0.13}$

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Comparative Study on Relationship between Vibration Level and Vibration Velocity (진동레벨과 진동속도의 상관성에 관한 비교연구)

  • Song, Ha-Lim;Noh, Young-Bae;Kang, Choo-Won
    • Explosives and Blasting
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    • v.29 no.2
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    • pp.43-50
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    • 2011
  • This study measured a vibration level at each distance of construction fields where blasts occur using Lion measuring instrument and used BlastmateIII to measure vibration velocity at the same distance. A total 130 blasts occurred with the weight of a total of 5,180 kg and the number of blast holes per blast was 5, 10 and 20. The weight of 4 kg was used for each hole. Vibrations caused by blast was measured at the distance with the same velocity and level. Measurements were carried 15~102 m away from the blast source. and 273 data on vibration velocity and level were obtained from eight measurements. It analysed data on vibration velocity measured based on existing correlation formulas and compared them to real measurements to analyse interrelationship.

The Effects of Cervical Manipulation on Blood Flow Velocity of Cranial Artery and Pain Level in Cervicogenic Headache Patients

  • Kang, Da-Haeng;Park, Seung-Kyu;Kang, Jeong-Il;An, Chang-Sik;Kim, Yong-Nam;Yoon, Hee-Jong;Koo, Ja-Pung;Chang, Duncan;Lee, Joon-Hee
    • Journal of International Academy of Physical Therapy Research
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    • v.1 no.2
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    • pp.99-106
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    • 2010
  • The purpose of this study was to identify the effects of manipulation on the velocity of cerebral blood flow and level of pain in cervicogeinc headache patients. The velocity of cerebral blood flow of 30 cervicogeinc headache patients(male=15, female=15, age=$24.00{\pm}3.60$) and 33 normal subjects(male=15, female=18, age=$23.27{\pm}3.00$) was compared. The 30 cervicogeinc headache patients were divided into suboccipitalis relaxation group, cervical manipulation group, and placebo group, and each were given different interventions. The velocity of cerebral blood flow and pain level was measured before intervention, and 1, 2, 3 weeks after intervention. The velocity of cerebral blood flow was measured with the Transcranial Doppler(TCD), and pain level was measured with visual analog scale(VAS). Blood flow velocity of middle cerebral artery in cervicogeinc headache patients was slower than those in healthy subjects. Physical therapy intervention did not have significant effect on velocity of cerebral blood flow, but slowly decreased at intervention for pain level increased. The suboccipitalis relaxation group and cervical manipulation group showed significant effect in decreasing pain level compared to the placebo group(p<.05). Directly applied manipulation therapy in the neck area not only has effect on joint of cervical and soft tissue but also on blood vessels and nerves which pass the neck area, and because of those results of manual therapy seems to help recovery.

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The Characteristics of Blasting Vibration in the Construction of Apartment and Buildings in Urban Area (도심지 발파공사장의 발파진동 특성)

  • 이연수;장서일
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.521-526
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    • 2004
  • In order to evaluate the effect of blasting vibration in buildings and it's resident located around blasting construction field in urban area, blasting vibration characteristics were measured the vibration level, vibration velocity. The 250g and 750g of charged powder were used at the apartment and at the ground, respectively. In the measurement of the ground, Z(perpendicularity) axis was the highest value in vibration level, but vertical axis was the highest value at 25m point and longitudinal axis was the highest value at 50m point in vibration velocity. The amount of measurement was high value when measuring point is higher than blasting source, while that of measurement was low value when measuring point is lower than blasting source. In the measurement of the apartment, 2 axis was the highest value in vibration level, but in vibration velocity transverse axis was the highest value at ground, was vertical axis at 1st floor, was longitudinal axis at 3rd floor and was vertical and longitudinal axis at 5th floor. The vibration level and the vibration velocity of 50m point showed higher correlation value than 25m point at the ground, but those of 25m point showed higher correlation value than 50m point at the apartment.

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The Characteristics of Blasting Vibration in the Construction of Apartment and Buildings in Urban Area (도심지 발파공사장의 발파진동 특성)

  • 장서일;이연수
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.7
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    • pp.632-638
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    • 2004
  • In order to evaluate the effect of blasting vibration in buildings and it's resident located around blasting construction field in urban area, blasting vibration characteristics were measured by the vibration level, vibration velocity. The 250g and 750g of charged powder were used at the apartment and at the ground, respectively. In the measurement of the ground, 2 (perpendicularity) axis was the highest value in vibration level, but vertical direction was the highest value at 25 m point and longitudinal direction was the highest value at 50 m point in vibration velocity. The amount of measurement was high value when measuring point is higher than blasting source, while that of measurement was low value when measuring point is lower than blasting source. In the measurement of the apartment, Z axis was the highest value in vibration level, but in vibration velocity transverse direction was the highest value at ground, was vertical direction at 1st floor, was longitudinal direction at 3rd floor and was vertical and longitudinal direction at 5th floor. The vibration level and the vibration velocity of 50 m point showed higher correlation value than 25 m point at the ground, but those of 25 m point showed higher correlation value than 50 m point at the apartment.