Wyniki wyszukiwania - Biblioteka Nauki

1

Towards the Design of Low Noise Level Wind Turbines

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Chaja P. , Koronowicz T.

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2009

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tom Vol. 13, No 4

393-401

EN

According to the authors’ hypothesis generation of high intensity noise is caused by generation of vorticity structures inducing velocities that can be locally higher than the velocity of sound. The localization and magnitude of vorticity concentration can be precisely defined on the basis of a double layer vortex model. Knowing the localization and mechanism of generation of significantly high induced velocities, turbine blades can be shaped in such a way so as to decrease the concentration of vorticity in these zones. According to the hypothesis described in this paper, a modification of turbine blades at the design stage results in their quieter operation for higher loads and wind velocities. The authors base their hypothesis on the experience from design works concerning low noise ship propellers. The following paper focuses on these tasks.

2

Szum mikrofalowych urządzeń odbiorczych telewizji satelitarnej

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Bogucki J.

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1998

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tom nr 6

436-441

PL

Omówiono przyczyny powstania szumów w mikrofalowych urządzeniach odbiorczych. Opisano wpływ szumów na odbiór sygnałów satelitarnych.

EN

Noise of microwave equipments is described. Its inffuence on receiving satellite signal is explained.

3

Wpływ transportu drogowego na klimat akustyczny stref zurbanizowanych w Polsce

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Lebiedowska B.

|

2000

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tom Z. 52

48-54

PL

Obowiązujqce od 1998 roku polskie przepisy o dopuszczalnej emisji hałasu do środowiska zbliżone są do obowiązujqcych w krajach UE. Przemiany zapoczątkowane w 1989r w Polsce doprowadziły do ożywienia działalności gospodarczej kraju i spowodowaly gwałtowny, nie notowany w żadnym z europejskich krajów, przyrost ilości samochodów. Jednocześnie brak obwodnic w dużych miastach oraz mała liczba dróg ekspresowych i autostrad spowodowały utrudniania komunikacyjne w miastach oraz częste przekroczenia dopuszczalnych wartości hałasu o 20 dB.

EN

Inhabitants of big world cities, including Poland, suffer from excessive noise for which road transport bears chief responsibility. Polish regulations concerning the permissible noise emission, in force since 1998, are comparable with EU regulations. Political system changes in Poland dating back to 1989, have encouraged economic activities and brought about a rapid increase in the number of cars, unparalleled in any other European country. However, insufficient number of ring roads, as well as a small number of expressway and motorways (ca. 1%), cause transport difficulies in cities and the level of permissible noise is often exceeded by up to 20 dB.

4

Delay-induced state transition and resonance in periodically driven tumor model with immune surveillance

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Yang T. , Han Q. , Zeng C. , Wang H. , Fu Y. , Zhang C.

Open Physics

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2014

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tom 12

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nr 6

383-391

EN

The phenomenon of stochastic resonance (SR) in a tumor growth model under the presence of immune surveillance is investigated. Time delay and cross-correlation between multiplicative and additive noises are considered in the system. The signal-to-noise ratio (SNR) is calculated when periodic signal is introduced multiplicatively. Our results show that: (i) the time delay can accelerate the transition from the state of stable tumor to that of extinction, however the correlation between two noises can accelerate the transition from the state of extinction to that of stable tumor; (ii) the time delay and correlation between two noises can lead to a transition between SR and double SR in the curve of SNR as a function of additive noise intensity, however for the curve of SNR as a function of multiplicative noise intensity, the time delay can cause the SR phenomenon to disappear, and the cross-correlation between two noises can lead to a transition from SR to stochastic reverse-resonance. Finally, we compare the SR phenomenon for the multiplicative periodic signal with that for additive periodic signal in the tumor growth model with immune surveillance.

5

Environmental Effects of Quarrying Activities in Akure, Ondo State, Nigeria

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Hamzart-Giwa O. G. , Odiyi B. O. , Afolabi O. J.

World News of Natural Sciences

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2023

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tom 49

122-136

EN

This study investigated the particulate matters, noise generated and the impacts of the activities on the quarry workers. Three quarries and a control site were selected for this study. A particulate matter counter (CLJ-D particulate counter) was used to count suspended particles and a hand-held device (SL-4012 sound meter) was used to determine the noise levels at different distances away from the crushing point (0 m, 50 m, 100 m, 150 m and 200 m). A well-structured closed questionnaire was used to collect information about demographic, health implications and status of respondents working at the quarry site. Samchaise quarry has the highest total suspended particulate matter (691.82 µg/m3 and 662.19 µg/m3) for 0 m and 50 m sampling point respectively. For 100 m, 150 m and 200 m, Dortmond quarry has the highest total suspended particulate matter of 609.82 µg/m3, 501.57 µg/m3 and 450.34 µg/m3 respectively. Dortmond quarry has the highest noise level (94.90 dB and 88.70 dB respectively) at 0 m and 50 m; Meanwhile, Ebenezer quarry has the highest noise level of 82.50 dB, 79.30 dB and 74.30 dB for 100 m, 150 m and 200 m respectively. Furthermore, out of the seventy (70) respondents interviewed, 22 (31.43%) of the workers had been working for over 5 years. Although, majority of the respondents 66 (94.29%) know the health implication of working in a quarry, only few respondents 6 (8.57%) used the protective gear always. In addition, 21 (39.62%) experienced catarrh monthly, headache 19 (35.85%) weekly, eyes ache 12 (22.64%), ear ringing 7 (13.21) at least daily, body ache 19 (35.85%) daily, skin itch 25 (47.17%) daily, and visual disturbance 10 (18.87%) daily. This study has shown that the quarry workers need to be trained and educated about the impacts of their activities in the environment.

6

Stochastic tumor growth system with two different kinds of time delay

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Dou C.-S. , Li D. , Wang C.-J.

Open Physics

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2011

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tom 9

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nr 3

616-620

EN

The dynamical properties of a noise-driven tumor cell growth system are investigated when there exist two different kinds of time delays, in the deterministic and fluctuating forces, respectively. Using the approximation probability density approach, the delayed Fokker-Planck equation is obtained. The effects of two different time delays on the stationary probability distribution (SPD), the mean value and the mean passage time (MFPT) are discussed. It is found that the time delay τ1 in the deterministic force can enhance tumor cell number, while the time delay τ2 in the fluctuating force can induce a decrease in tumor cell numbers. On the other hand, while τ1 can hold back the extinction of tumor cells, τ2 can speed up their extinction.

7

Effects of noise on periodic orbits of the logistic map

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Li F.-g.

Open Physics

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2008

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tom 6

|

nr 3

539-545

EN

Noise can induce an inverse period-doubling transition and chaos. The effects of noise on each periodic orbit of three different period sequences are investigated for the logistic map. It is found that the dynamical behavior of each orbit, induced by an uncorrelated Gaussian white noise, is different in the mergence transition. For an orbit of the period-six sequence, the maximum of the probability density in the presence of noise is greater than that in the absence of noise. It is also found that, under the same intensity of noise, the effects of uncorrelated Gaussian white noise and exponentially correlated colored (Gaussian) noise on the period-four sequence are different.

8

Investigation of noise in the field of rail transport

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Nader M.

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2000

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tom Vol. 12, iss. 3

39-48

EN

This paper presents experimental investigations of audible noise within the range of frequency 31,5 + 8000 Hz in selected rail-vehicles EN-57, EU-07 and ET-22. Herein the level of audible acoustic pressure that influenced the driver in different working conditions with fixed travel speed is described.

PL

W pracy przedstawiono badania eksperymentalne hałasu słyszalnego w zakresie częstotliwości 31,5-^8000 Hz w wybranych pojazdach szynowych EN-57, EU-07 oraz ET-22. Omówiono badanie poziomu ciśnienia akustycznego hałasu słyszalnego oddziałującego na maszynistę w różnych warunkach pracy.

9

Badania hałasu maszyn i obrabiarek, wykorzystujących przekładnie śrubowe toczne

100%

Pieniecki P.

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2006

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tom nr 7-8

39-42

PL

W artykule omówiono różne źródła hałasu nowoczesnej obrabiarki. Celem pracy konstruktorów jest uzyskanie możliwie minimalnej wartości hałasu, co można zrealizować przez obniżenie hałasu z głównego źródła, jakim jest przekładnia śrubowa toczna. Omówiono zagadnienia związane z problemami hałasu przekładni śrubowych tocznych, a także podjęto próbę ich wyjaśnienia.

EN

In the paper, different sources of the noise in modern machines were discussed. A goal of the work of machine designers was the reduction of noise level. It could be achieved by reduction of nose level of the ball screw system - the main source of the noise. There were discussed problems connected with the noise levels of the ball screw systems.

10

Patenty wibroakustyczne bydgoskiego środowiska naukowego

100%

Wernerowski K.

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1999

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tom Z. 44 (221)

171-176

PL

Wykonano analizę patentów bydgoskiego środowiska naukowego zmniejszających poziom parametrów drgań i emisji hałasu. Przedstawiono również patenty osłon, ekranów i przestrzennych pochłaniaczy akustycznych.

EN

Vibroacoustic patents analysis of Bydgoszcz scientific community reducing the vibration and noise parameters level was done. Shield, screen and special acoustic absorber patents were also presented.

11

Annoyance Related to Wind Turbine Noise

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Pawlaczyk-Łuszczyńska M. , Dudarewicz A. , Zaborowski K. , Zamojska-Daniszewska M. , Waszkowska M.

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nr 1

12

Pattern selection processes and noise induced pattern-forming transitions in periodic systems with transient dynamics

100%

Kharchenko D. , Kharchenko V. , Lysenko I.

Open Physics

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2011

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tom 9

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nr 3

698-709

EN

We apply the phase field crystal method for nonequilibrium patterning to stochastic systems with an external source in which transient dynamics is essential. Considering a prototype model for a one-component periodic system subjected to external influence kind of irradiation we study properties of pattern selection processes and external noise induced pattern-forming transitions. These processes are examined by means of the structure function dynamics analysis. Nonequilibrium pattern-forming transitions are analyzed numerically.

13

A sudden sensorineural hearing loss caused by a thunderbolt

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Borowska K. , Pietniczka-Załęska M. , Budzynowska K.

Otolaryngologia Polska

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2008

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tom 62(6)

755-757

EN

The authors present a case of 12-years old girl with sudden sensorineural hearing loss caused by computer adapter explosion during the storm. She denied any tinnitus and vertigo. She was admitted immediately to ENT Ward. Audiometric examination showed rigt ear deaffness. She administered vasodilatators, oxygen, Vitamin B complex, 1% xylocain, dextran, betahistin and steroids i.v. After few days she started to hear her rigt ear. Conrtol audiometric examination showed hearing in normal range. In a case of sudden deaffness is important to strart treatment as qiuck as is possible. And we should remember that new technics with nature could be dangerous to our health.

14

Problemy oceny poziomu hałasu na obszarze parków miejskich

100%

Kujawski E. , Luther L. , Sztubecka M.

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2008

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tom R. 105, z. 2-Ś

165-170

PL

W artykule zwrócono uwagę na odmienność w postrzeganiu słyszanych dźwięków przez urządzenia i ludzi. Próba porównania pomierzonych wartości z odczuciami wykazała większą wrażliwość odbiorców na dochodzące hałasy.

EN

The paper summarizes the dissimilarity in perception of heard sound by soundmeter and people. The test of comparison measurements with feelings shows bigger sensitivity of recipient for coming noise.

15

Noise measurement set-ups for fluctuations-enhanced gas sensing

100%

Kotarski M. , Smulko J.

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2009

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tom Vol. 16, nr 3

457-464

EN

Resistance fluctuations observed as voltage fluctuations across resistance gas sensors can increase the sensibility and selectivity of gas sensing. This conclusion leads to the question how to prepare in practice a cheap measurement system for gas detection when resistance gas sensors of various resistance are applied. Therefore it is valuable to consider different noise measurement systems that would apply fluctuation-enhanced gas sensing. This study presents two solutions of noise systems that can be used for noise measurements in Taguchi gas sensors currently available on the market and the prototype monosized nanoparticle gas sensors having much greater DC resistance than the sensors currently on sale.

16

REQUIREMENTS FOR EVALUATION OF NOISE IN WORK ENVIRONMENT

100%

Čekan P. , Szabová Z. , Belčík M. , Harangozó J.

Problemy Profesjologii

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2014

|

nr 1

141-147

EN

The article analyzes the legislative requirements related to evaluation of noise generated by working environment. Specifies to the detail particular activities within categories of work for which there are declared legislative limits of the standardized sound level LAEX,8h. It also briefly describes the work environment of the process welding from the perspective of noise exposure, whilst focus is on the determination of sound pressure values for the selected welding technology.

PL

W artykule przeanalizowano wymagania prawne dotyczące oceny hałasu generowanego w środowisku pracy. Określono szczegóły działań odnoszących się do kategorii prac, dla których nie są deklarowane ograniczenia prawne, znormalizowanego poziomu dźwięku LAEX,8h. Opisano również środowisko pracy w odniesieniu do procesu spawania z punktu widzenia narażenia na hałas, ze szczególnym uwzglednieniem wartości ciśnienia dźwięku dla wybranej technologii spawania.

17

Antyhałasowe tendencje w konstrukcjach reduktorów ciśnienia gazu

100%

Menżyński M.

|

2001

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tom Nr 7

231-236

EN

Noise generating in a traditional regulator. Gas flow throttling with concurrent acoustic energy dissipation. Use of multistage gas expansion. Gas flow directing in a valve axle. Schemes of regulators by different producers.

18

Algorithms of chemicals detection using Raman spectra

100%

Kwiatkowski A. , Gnyba M. , Smulko J. , Wierzba P.

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2010

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tom Vol. 17, nr 4

549-559

EN

Raman spectrometers are devices which enable fast and non-contact identification of examined chemicals. These devices utilize the Raman phenomenon to identify unknown and often illicit chemicals (e.g. drugs, explosives) without the necessity of their preparation. Now, Raman devices can be portable and therefore can be more widely used to improve security at public places. Unfortunately, Raman spectra measurements is a challenge due to noise and interferences present outside the laboratories. The design of a portable Raman spectrometer developed at the Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology is presented. The paper outlines sources of interferences present in Raman spectra measurements and signal processing techniques required to reduce their influence (e.g. background removal, spectra smoothing). Finally, the selected algorithms for automated chemicals classification are presented. The algorithms compare the measured Raman spectra with a reference spectra library to identify the sample. Detection efficiency of these algorithms is discussed and directions of further research are outlined.

19

GPS kontra zagłuszanie

100%

Figurski M. , Szołucha M. , Mielnik P. , Gałuszkiewicz M. , Wrona M. , Szymański P.

|

2011

|

tom nr 1

46-51

PL

Wpływ zakłóceń na pomiary GPS. Czasami wykonanie pomiaru GPS jest z niewiadomych przyczyn niemożliwe lub otrzymane wyniki bardzo mocno odbiegają od zakładanych dokładności. Powodów najczęściej doszukujemy się w czynnikach zewnętrznych. Analizując różne przypadki wadliwych pomiarów, można stwierdzić, że najczęstrzą przyczyną problemów są zakłócenia elektromagnetyczne. Oczywiste jest, że nie wszystkie i nie zawsze oddziaływania promieniowania elektromagnetycznego powodują zanik lub degradację częstotliwości nadawanych przez GNSS. Dlatego Zespół Centrum Geomatyki Stosowanej wykonał szereg badań, których efekty zostały opisane w tym artykule. Generalizując, wpływ zewnętrznych pól magnetycznych można podzielić na dwie grupy: tzw. częstotliwości harmonicznych (których oddziaływanie może w określonych warunkach wpływać na odbiór sygnałów GPS) i celowe zakłócenia przy wykorzystaniu dostępnych w handlu urządzeń do eliminowania sygnałów GPS.

EN

Influence of interferences on GPS measurements. Using GPS receivers we come across various problems related to the measurement accuracy. There are cases where the measurement procedures are hard to follow or a measurement is almost impossible and the results are far from being precise/perfect. The reasons of measurement failure might be different, but they are usually caused by the external factors. We may assume that the most possible explanation is the electromagnetic disturbance, but we should also remember that electromagnetic influence is not always the reason of GNSS frequencies fading and degrading. The Centre of Applied Geomatics has done a series of research and the results are described in this article. The influence of external electromagnetic field might be divided into two classes: harmonic frequency (which may, in certain environment, influence the GPS signals) and so called disturbance on purpose (witch is obtained through the use of available disturbance equipment to eliminate GPS signals).

20

Zasady oceny uciążliwości hałasu przemysłowego

100%

Żuchowicz-Wodnikowska I.

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2004

|

tom nr 4

16-17

PL

W artykule przedstawiono podstawowe zasady postępowania przy określaniu uciążliwości hałasu od źródeł przemysłowych. W celu właściwej oceny przewidywanego hałasu w środowisku przeprowadzono obliczenia uwzgędniające parametry akustyczne źródeł hałasu oraz warunki propagacji dźwięku.