Acoustic performance of a concentric circular Helmholtz resonator with an extended neck is investigated theoretically, numerically, and experimentally. The effect length shape of, the perforations on extension examined resonance frequency transmission loss. A two-dimensional analytical method developed for constant cross-sectional area, while three-dimensional boundary element applied variable area perforated extension. Lumped one-dimensional approaches are also included to illustrate higher...

Hydrogen peroxide plays a key role as second messenger in the normal cellular signaling but its overproduction has been implicated various life-threatening diseases. Peroxalate chemiluminescence is light emission from three component reaction between peroxalate, hydrogen and fluorophores. It proven great potential methodology to detect physiological environments because of excellent sensitivity specificity peroxide. We developed chemiluminescent micelles composed amphiphilic polymers,...

Acoustic impedance of perforations in contact with fibrous material, as well air alone, is experimentally determined the absence mean flow. Different porosities (2.1, 8.4, 13.6, and 25.2%) hole diameters (0.249 0.498cm) are applied for perforations, along two fiber filling densities (100 200kg∕m3) to illustrate effect variations such parameters on perforation impedance. A modified tube setup developed measurement acoustic alone. The complex wave-number characteristic material also obtained...

The effect of perforation impedance on the acoustic behavior reactive and dissipative silencers is investigated using experimental computational approaches. boundary element method (BEM) applied for prediction transmission loss with different geometries. variations are considered in porosity (8.4 25.7%) hole diameter (0.249 0.498cm) perforations both silencers, as well fiber filling density (100 200kg∕m3) latter. a number contact air alone fibrous material has been incorporated into...

Tinea incognito (TI) is a dermatophytic infection of the skin that modified by steroid use. As result, it shows atypical clinical presentations can lead to misdiagnosis. TI occurring on face most frequently misdiagnosed as cutaneous fungal infection, however, very limited information available facial TI. This study aimed characterize clinical, dermoscopic and mycological features We retrospectively evaluated 38 patients with mycologically proven at single institution in Korea between July,...

Torsional systems with clearance-type nonlinearities have inherent vibratory problems such as gear rattle. Such vibro-impacts generally occur on the unloaded pairs of a vehicle correlated firing excitation an engine. This study investigates rattle phenomena different conditions and various system parameters. First, linear time-invariant model six degrees freedom is constructed then numerical analysis applied to motion. Smoothening factors for clutch stiffness hysteresis are employed...

Tinea capitis is an infection of the scalp hair follicles and surrounding skin that primarily occurs in prepubertal children. Microsporum canis remains most common pathogen causing tinea Asian countries, including South Korea, although causative organism this condition varies across geographical regions time periods. Systemic antifungal agents are mainstay treatments for capitis; however, therapeutic responses to drugs may vary depending on species, treatment failure occur owing drug...

Vitiligo is a common acquired skin depigmentation disorder and associated with various other autoimmune diseases which include thyroid disease rheumatoid arthritis. Similarly, adenotonsillar (ATD) may induce inflammatory or in organs the skin. However, influence of ATD on development vitiligo has not been studied.To determine association between adenotonsillectomy, vitiligo.Using data from National Health Insurance Service database, patients diagnosed 2008 2010 were included study. We...

The present analytical, computational, and experimental work investigates the effects of length shape an extended neck on acoustic attenuation performance a concentric circular Helmholtz resonator with fixed cavity. For extension constant cross-sectional area, 2-D analytical approach is developed to determine behavior, while 3-D boundary element method employed when area allowed vary. These results are compared with: (1) data obtained from impedance tube setup, (2) classical lumped analysis...

Bullous pilomatricoma is a rare variant of pilomatricoma. As it has been published in sporadic case reports, limited understanding its clinicopathological characteristics restricts effective diagnosis and treatment. This study aimed to analyze the immunohistochemical bullous better understand transformation The authors conducted retrospective 12 patients with compared their clinical, histopathological, data those ordinary showed no sex preference, mean onset age 31.2 years. common sites were...

The acoustic performance of Helmholtz resonators with different configurations in the presence mean flow is experimentally investigated. transmission loss measured using a flow-impedance tube setup to identify effects. First, under two conditions, grazing and direct flow, are considered at Ma=0.05 0.1. Then impact on leakage holes also demonstrated. For holes, single peak identified Ma=0.0 However, peaks appear as number opening increases. experimental results show that effect strongly...

Stevens-Johnson syndrome and concurrent hand foot during treatment with capecitabine: A case report

Helmholtz resonator has been used, especially in intake and exhaust systems of vehicles, due to its good noise reduction characteristics at low frequencies. Many approaches have developed predict the acoustic behavior with assumption that there is no leakage from resonator. However, may be affected by which exist manufacturing processes or on purpose. This study investigates effect two practical examples. One a gap between baffle housing other one drain holes baffle. The measured...

Based on ISO 7235, an experimental setup to measure the acoustic performance of splitter type dissipative silencers was fabricated. The length each duct, sound source, microphone locations, modal filter, and anechoic termination were considered in design this setup. filter is a particularly important factor because it affects limit measurement. effects number splitters, absorptive material density, perforate plate, media noise reduction sample experimentally investigated. results show that...

Acoustic performance of splitter silencers was investigated by using 3-dimensional commercial software and experiments. Flow resistivity sound absorbing material indirectly estimated an impedance tube setup a curve fitting method. In addition the acoustic perforated plate determined empirical formulation. Such properties have been used as input parameters in software. The prediction for silencer with 1000 mm length compared experimental result. numerical method is then applied to identify...

The effect of leakage in Helmholtz resonators has been experimentally and numerically investigated. Transmission loss a resonator having gap between the cavity main duct is measured using an impedance tube setup. on transmission examined different amounts openings. Experimental results are then compared with predictions from boundary-element method. study shows that increases resonance frequency substantially widens loss. Hence, needs to be taken into account for accurate resonators.

Acoustic impedance of perforations in contact with fibrous material is experimentally determined for various hole geometries and filling densities the absence mean flow. Two setups are developed to measure perforation acoustic properties absorbent, while yielding empirical expressions both. The experimental results show that both real imaginary components substantially increase as a result material, whereas they generally decrease increasing porosity given density. this study implemented...