Autor: Demir, Ahmet - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Scattering of Sound Waves in Two Stepped Non-uniformly Lined Duct
Autorzy:: Tiryakioglu, Ayse
Demir, Ahmet
Powiązania:: https://bibliotekanauki.pl/articles/177113.pdf
Data publikacji:: 2020
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:: Wiener-Hopf
scattering matrices
step discontinuity
impedance discontinuity
duct
Opis:: Scattering of sound waves in two stepped cylindrical duct which walls are coated with different acoustically absorbent materials is investigated by using Wiener-Hopf technique directly and by determining scattering matrices. First, by using Fourier transform technique we obtain a couple of modified Wiener-Hopf equations whose solutions involve four sets of infinitely many unknown expansion coefficients providing systems of linear algebraic equations. Then we determine scattering matrices of the problem and we state the total transmitted field by using generalized scattering matrix method. Numerical results are compared for different parameters.
Źródło:: Archives of Acoustics; 2020, 45, 3; 511-520
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Sound Wave Radiation from Partially Lined Duct
Autorzy:: Tiryakioglu, Burhan
Demir, Ahmet
Powiązania:: https://bibliotekanauki.pl/articles/177899.pdf
Data publikacji:: 2019
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:: Wiener-Hopf
Fourier transform
duct
saddle point
Opis:: The radiation of sound waves from partially lined duct is treated by using the mode-matching method in conjunction with the Wiener-Hopf technique. The solution is obtained by modification of the Wiener-Hopf technique and involves an infinite series of unknowns which are determined from an infinite system of linear algebraic equations. Numerical solution of this system is obtained for various values of the problem parameters, whereby the effects of these parameters on the sound diffraction are studied. A perfect agreement is observed when the results of radiated field are compared numerically with a similar work existing in the literature.
Źródło:: Archives of Acoustics; 2019, 44, 2; 239-249
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Effects of persulfate, peroxide activated persulfate and permanganate oxidation on treatability and biodegradability of leachate nanofiltration concentrate
Autorzy:: Guvenc, Senem Yazici
Varank, Gamze
Demir, Ahmet
Powiązania:: https://bibliotekanauki.pl/articles/2032960.pdf
Data publikacji:: 2021
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: COD
nanofiltration
NF
ChZT
nanofiltracja
Opis:: The effects of persulfate (PS), peroxide activated persulfate (P-PS) and permanganate (PM) oxidation processes on leachate nanofiltration (NF) concentrate treatment have been activated. Additionally, COD fractions were determined and compared before and after each oxidation process. The total COD removal efficiencies by the oxidation processes using PS, P-PS, and PM as the oxidants were determined to be 24.5%, 32.9%, and 39.5%, respectively. The biodegradable COD fraction increased from 6.37% to 9.25%, 11.51%, and 13.64% after the PS, P-PS, and PM oxidation processes, respectively. About 25%, 34%, and 46% removal efficiencies of the inert COD content of the concentrate were obtained after the PS, P-PS and PM oxidation processes, and the soluble COD fraction increased from 71.1% to 87.2%, 89.0% and 84.6% by the PS, P-PS and PM oxidation processes, respectively. Although the highest removal efficiencies were achieved by PM oxidation with the lowest operational cost, all of the processes may be suggested as efficient methods for conversion of insoluble COD into the soluble COD fraction and for inert COD removal. The results of the study showed that the PS, P-PS, and PM oxidation processes may be effectively utilized as post-treatment techniques for leachate NF concentrate treatment.
Źródło:: Environment Protection Engineering; 2020, 46, 3; 97-108
0324-8828
Pojawia się w:: Environment Protection Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Byssinosis and COPD rates among factory workers manufacturing hemp and jute
Autorzy:: Er, Mukremin
Emri, Salih A.
Demir, Ahmet U.
Thorne, Peter S.
Karakoca, Yalcin
Bilir, Nazmi
Baris, Izzettin Y.
Powiązania:: https://bibliotekanauki.pl/articles/2177088.pdf
Data publikacji:: 2015-09-15
Wydawca:: Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:: byssinosis
endotoxin
COPD
hemp
jute
occupational health
Opis:: Objectives Prior studies have been performed on cotton textile plants throughout the world. This study was planned to identify the rate of byssinosis and chronic obstructive pulmonary disease (COPD) in hemp and jute workers and those who worked with both of them. Material and Methods The study was realized in a factory which consecutively processed hemp and jute. The study enrollment included 266 people, 164 of whom were active workers and 102 were retired. A questionnaire, plain chest X-rays, physical examination and pulmonary function tests were performed. Dust levels were measured in various sections of the factory during 8 h work shifts. Endotoxin levels of various quality hemp fibers and dusts were measured. Results The rate of byssinosis (28.2%) was higher among the workers that who exposed to both jute and hemp dust. The frequency of chronic bronchitis in retired workers who previously smoked was higher (20%) as compared to currently smoking workers (17%). High dust levels were measured in some parts of the factory (mean (M) = 2.69 mg/m³). Working in dense dust areas, active smoking, being older than 40 years of age, being an ex-smoker, and working in the factory for a period exceeding 15 years were significantly associated with bronchitis and emphysema development. High endotoxin levels were determined for fine hemp dust (605 EU/mg), coarse hemp dust (336 EU/mg) and poor quality hemp fibers (114 EU/mg), whereas in fresh hemp stalks the level of endotoxin was determined to be lower (0.27 EU/mg). Conclusions Because of high exposures to jute and hemp dusts that are associated with high byssinosis rates, personal protection and environmental hygiene is crucial to prevention of byssinosis.
Źródło:: International Journal of Occupational Medicine and Environmental Health; 2016, 29, 1; 55-68
1232-1087
1896-494X
Pojawia się w:: International Journal of Occupational Medicine and Environmental Health
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Can olive oil prevent distal colon mucosal atrophy caused by disuse in rats with colostomy? An experimental animal study
Autorzy:: Atıcı, Ahmet
Demir, Emel
Gürsoy, Didar
Çelikkaya, Mehmet
Akçora, Bülent
Powiązania:: https://bibliotekanauki.pl/articles/1391554.pdf
Data publikacji:: 2021
Wydawca:: Index Copernicus International
Tematy:: children
distal colon mucosal atrophy caused by disuse
olive oil
Opis:: Aim: This study aims to investigate the effects of pure olive oil on mucosal atrophy of the distal colon in rats. Material and methods: The study included 28 male albino Wistar rats weighing 300–350 g. A total of 28 animals were randomly allocated to four groups: group 1: control group (n = 6); group 2: ostomy group (n = 6); group 3: ostomy + saline group (n = 8); group 4: ostomy + olive oil group (n = 8). By definition, group 1 did not undergo any procedure. The same surgical procedure was performed for groups 2, 3, and 4 as described below. In all animals from these groups, a two-centimeter-long mid-line incision was made and the colon was divided into 5 cm sections, measured from the distal colon to the caecum. Proximal and distal stomas were created 2 cm apart in the midline with the use of single-layer interrupted sutures. All rats were kept under close daily observation until they were terminated postoperatively after the 1st month. Animals from group 2 did not undergo any additional procedures, while those fromgroups 3 and 4 were given 2 mL of saline and olive oil twice a day, respectively. At the end of the 1st month, the rats were re-operated through the same approach. Biopsies were taken from the proximal and distal stomas of all rats in the same manner for further histopathological analysis. Results: Group 1 showed no significant differences in terms of mucosal thickness, muscular thickness, wall thickness or colonic lumen diameter between the proximal and distal segments of the colon. Although there were significant differences between the proximal and distal colostomies for each parameter in groups 2, 3, and 4, the mucosal thickness, muscular thickness, wall thickness, and colonic lumen diameter differences for proximal and distal ostomies were very small in group 4 when compared to groups 2 and 3. Conclusion: The administration of pure olive oil through the distal colon before colostomy closure may reduce the difference in diameter between the proximal and distal intestinal segments. As a result, a more straightforward surgical procedure may be achieved.
Źródło:: Polish Journal of Surgery; 2021, 93, 4; 35-40
0032-373X
2299-2847
Pojawia się w:: Polish Journal of Surgery
Dostawca treści:: Biblioteka Nauki

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