• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.2
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• pp.58-64
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• 2012

Hysteresis phenomena in fluid flow systems are frequently encountered in many industrial and engineering applications and mainly appear during the transient processes of change of the pressure ratio. Shock-containing flow field in supersonic nozzles is typically subject to such hysteresis phenomena, but associated flow physics is not yet understood well. In the present study, experimental work has been carried out to investigate supersonic nozzle flows during the transient processes of change in the nozzle pressure ratio. Time-dependent surface wall pressures were measured by a multiple of pressure transducers and the flow field was visualized using a nano-spark Schlieren optical method. The results obtained show that the hysteresis phenomenon is strongly dependent on the nozzle geometry as well as the time scale of the change of pressure ratio.

• Journal of radiological science and technology
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• v.24 no.1
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• pp.11-15
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• 2001

Symptoms of caliceal diverticular stones are commonly associated with pain, recurrent urinary tract infection and hematuria. The aim of this study is to select the proper patient for the application of more successful extracorporeal shock wave lithotripsy(ESWL) as a treatment of caliceal diverticular stone. 16 patients with caliceal diverticular stones were treated with ESWL, and all patients had single caliceal diverticulum. The diagnosis of caliceal diverticulum with stones was made by intraveneous pyelography to all patients. On these intravenous pyelogram, we also classified diverticular type, whether the diverticular neck is connected with urinary tract patently, diverticular site and stone number and size. All patients were followed after ESWL by plain film of the kidneys, ureters and bladder and interviewed. Of all patients 44% was shown stone-free completely, also 83% was rendered symptom-free. All patients whose diverticular neck connected with urinary tract patently on the intraveneous pyelogram became stone- free. Of solitary stone 60% and multiple stones(more than 2) 17% became stone free. All patients rendered stone-free became symptom-free, and of patients with residual stones 44% became symptom-free. The patients with infection before ESWL 75% had residual stones, of these patients 33% had slightly flank pain, and 25% of patients with stones recurred become stone-free. We propose that more successful ESWL for patients with caliceal diverticular stones select satisfactory patients including that the diverticular neck is connected with urinary tract patently, solitary stone and no infection simultaneously.

• Journal of Korea Port Economic Association
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• v.24 no.1
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• pp.1-10
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• 2008

This paper analyses the dynamic causal relationship between vessel export and economic growth using annual data over the period from 1977 to 2006. Tests for ADF unit-roots, the dynamic vector using Johansen's multiple cointegration procedure, dynamic vector error correction model and impulse response function are presented. The findings of the Granger test suggest that vessel export Granger-causes economic growth in the short-run and economic growth Granger-causes exports in the short and long-run. The empirical results of impulse-response analysis show that the vessel export to a shock in real GDP responds positively and the real GDP responds positively to the shocks in vessel export. Also, the results indicate that the impact of vessel export shock on the real GDP is short-lived.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.7 no.1
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• pp.83-86
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• 2004

Food allergy is not uncommon among small children. Cow milk and eggs are most frequently incriminated as the major cause of food allergy. A 4-month-old female infant who did not have a previous history of contact with the egg developed anaphylactic shock when an emulsion of raw egg white was rubbed on the buttock by her mother to relieve erosive diaper dermatitis. She had been fed on breast milk. She had no past medical history of any other allergy and no family history of atopy, asthma or allergic rhinitis. Her IgE PRIST was 29.46 IU/ml and multiple antigen simultaneous testing chemiluminescent assay for food specific IgE antibody showed a level 4 positive value only to egg white.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.25 no.3
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• pp.125-130
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• 2019

Shock and vibration inputs are transmitted from the vehicle through the packaging to the fruit. Inside, these cause sustained bouncing of fruits against each other and container wall. These steady state vibration input may cause serous fruit injury, and this damage is particularly severe whenever the fruit inside the package is free to bounce, and is vibrated at its resonance frequency. The determination of the resonance frequencies of the fruit and vegetables may help the packaging designer to determine the proper packaging system providing adequate protection for the fruit, and to understand the complex interaction between the components of fruit when they relate to expected transportation vibration inputs. Instrumentation and technologies are described for determining the vibration response characteristics of the pears for exporting with frequency range from 10 to 200 Hz, sweep rate of 1 octave/min, sweep method of logarithmic up and down and acceleration levels of 0.2, 0.4, 0.6, 0.8 and 1.0 G considering the domestic transportation environment. The resonance frequency of the pears ranged from 49.04 to 87.16 Hz and the amplitude at resonance was between 0.96 and 4.02 G in test frequency band and acceleration level. The resonance frequency and amplitude at resonance frequency band of the pears decreased with the increase of the sample mass. The multiple nonlinear regression equations for predicting the resonance frequency of the pears were developed using the independent variables such as mass, input acceleration.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.12 no.2
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• pp.97-102
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• 2006

Shock and vibration inputs are transmitted from the transporting vehicle through the packaging to the fruit. The vibration causes sustained bouncing of fruits against each other and the container wall. The steady state vibration input may cause serous fruit injury, and the damage is particularly severe if the fruits are bounced at its resonance frequency. The determination of the resonance frequencies of the fruits and vegetables may help the packaging designer to determine the proper packaging system providing adequate protection for the fruits, and to understand the complex interaction between the components of the fruits when they relate to expected transportation vibration inputs. To analyze the vibration properties of the watermelon for optimum packaging design during transportation, sinusoidal sweep vibration tests were carried out. The resonance frequency of the watermelon ranged from 19 to 32 Hz and the amplitude at resonance was between 1.6 and 2.9 G. The resonance frequency and amplitude at resonance frequency band of the watermelon decreased with the increase of the sample mass. The multiple nonlinear regression equation for predicting the resonance frequency of the watermelon were developed using the independent variables such as mass, input acceleration and sphericity.

• The Journal of the Acoustical Society of Korea
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• v.34 no.1
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• pp.60-65
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• 2015

In this paper, we used the sound of gunshots recorded by multiple microphones to increase the accuracy of the calculation of the distance between sniper and the microphone array. This method is crucial for achieving military objectives. Gunshots are comprised of the explosion of driving gas from the muzzle and the supersonic shock wave from the flying bullet. The original distance calculation method compares the time difference of arrival and angle of incidence to estimate the sniper's location. The disadvantage of this method is that when the angles of incidence coincide the margin of error increases, to solve this problem we suggest a new method using the characteristic changes of the shock wave with the increase of perpendicular distance between the microphone and the trajectory of the bullet. This theory is verified by experiments.

• Journal of Ocean Engineering and Technology
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• v.33 no.4
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• pp.364-376
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• 2019

When underwater blasting is conducted, both shock waves and water waves have an effect on adjacent coastal areas. In this study, an empirical formula for estimating the details of water waves caused by underwater blasting was applied to a non-reflected wave generation system, and a 3D numerical wave tank (NWT) was improved to reproduce the generation and propagation of such water waves. The maximum elevations of the propagated water waves were comparatively analyzed to determine the validity and effectiveness of the NWT. Good agreement was demonstrated between the empirical and simulation results. The generation and propagation of water waves were also simulated under each underwater blasting scenario for the removal of the Todo islet at the Busan Newport International Terminal (PNIT). It was determined that the water waves generated by the underwater blasting scenario examined in this study did not have a significant impact on the PNIT. In addition, multiple-charge blasting caused higher wave heights than single-charge blasting. As the amount of firing charge increased, the wave height also increased. Finally, larger water waves were generated during the later blasting conducted at a deeper depth as compared with an earlier blasting conducted at a relatively shallow depth.

• Iberoamérica
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• v.23 no.2
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• pp.273-307
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• 2021

The covid 19 pandemic led to an economic collapse and multiple impacts upon Argentina's labour dynamics. As well as in other parts of the region, falls in employment rates (both due to an increase in unemployment and significant withdrawals from the labour force) were combined with wage reductions for those who were able to keep their jobs. Thus, two important processes for the labour market complimented each other: a structural shock associated with a tasks automation as a reorganisation and substitution of factors, with a cyclical recession caused by the pandemic. The international experience shows the amplifying impact the latter has on the former, generating long-term consequences mainly in routine-intensive jobs. However, the knowledge-intensive services sector appears to be the most capable of cushioning the recessionary shock (both in terms of wages and labour absorption), even with nuances within the sector depending on the extent of the shutdown measures and its capability to switch to remote work. Finally, the task approach is decisive in capturing the ability to adapt both the cyclical and structural processes, absorbing a large part of the explanatory potential that sectoral classifications tend to bring about.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.576-582
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• 2019

Staphylococcus pseudintermedius is an opportunistic pathogen in dogs and is recognized as a zoonotic pathogen causing public health concern. Although canine-associated S. pseudintermedius has mainly been recognized for its antimicrobial resistance and ability to cause skin infections in dogs, information on antimicrobial resistance profiles and enterotoxigenicity of S. pseudintermedius in livestock is very limited. In this study, we investigated the prevalence of 18 different staphylococcal enterotoxin (SE) genes and toxic shock syndrome toxin gene (tst-1) in S. pseudintermedius strains isolated from dogs, pigs, and beef cattle. Moreover, antimicrobial resistance profiles of the strains were determined along with the presence of mecA and SCCmec types. Except for one bovine isolate, all S. pseudintermedius isolates from dogs and pigs were resistant to multiple drugs (≥ 4 different drugs). Four out of six canine isolates were methicillin resistant and carried SCCmec type V. In addition, 11 different SE genes (seb, sec, see, seg, sei, sej, sel, seo, sep, seq, and seu) and tst-1 were identified in S. pseudintermedius isolates from dogs, pigs, and beef cattle. Most S. pseudintermedius isolates (83%) harbored multiple SE genes, and sel (42%) and sep (42%) were most frequently detected in the isolates. Our results suggested that S. pseudintermedius isolates from livestock and companion animals may serve as a reservoir for SE genes and antimicrobial resistance.