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1
Content available Methodical aspects of determination of parameters which characterize thermal balance of a plastic tunnel
Kurpaska S., Lis W., Vogelgesang J.
Agricultural Engineering
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2016
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Vol. 20, No. 3
83--93
EN
The paper presents methodology of measuring the values which characterize the thermal balance in a horticultural facility. Thermal transmittance through a plastic tunnel cover and the ratio of solar radiation energy conversion into heat were analysed in detail. The research was carried out in real time with closed ventilators, where no plants were cultivated during the tests. The utility surface area was 144 m2, the cover was 289 m2 and its volume was 508 m3. Basing on the standard relations, first of all, thermal transmittance through a cover was measured. The ratio was measured with the use of standard criteria equations. Then, a correlation equation, which makes its course dependent on the climate parameters (the wind speed and temperature difference between the interior of the facility and its surroundings), was found. Knowing the course of the ratio in the function of the climate parameters, the value of the ratio of solar radiation conversion into heat stored in the facility was measured. Both parameters (thermal transmittance and solar radiation conversion ratios) were calculated from the thermal balance equaition where the change of the energy stored inside the facility was compared to the heat losses through a cover (for thenual transmittance) and the profit (in case of solar radiation conversion). For the obtained values, using the non-linear estimation procedure (with quasi-Newtom method with maintenance of the correlation coefficient of 0.001) the change of both ratios in the function of easily measured parameters of climate inside and outside the facility was found out. In the investigated conditions, the average value of thermal transmittance through a cover was 5.32 W·m-2·K-1, and the solar radiation conversion into heat was 0.36. The values and their course from the climate parameters inside and outside the facility may be used for controlling the amount of supplied heat and location of ventilators.
PL
W pracy przedstawiono metodykę do wyznaczania wielkości charakteryzujące bilans cieplny w obiekcie ogrodniczym. Szczegółowej analizie poddano współczynnik przenikania ciepła przez transparentną osłonę tunelu foliowego oraz współczynnik konwersji energii promieniowania słonecznego w ciepło. Badania przeprowadzono w rzeczywistym obiekcie przy zamkniętych wietrznikach, w którym podczas badań nie uprawiano roślin. Powierzchnia użytkowa tunelu wynosiła 144 m2, osłony 289 m2, zaś jego pojemność była równa 508 m3. Bazując na standardowych zależnościach w pierwszej kolejności wyznaczono współczynnik przenikania ciepła przez osłonę. Współczynnik wyznaczono korzystając ze standardowych równań kryterialnych. W następnej kolejności znaleziono równanie korelacyjne uzależniające jego przebieg od parametrów klimatu (prędkość wiatru oraz różnica temperatury między wnętrzem obiektu a jego otoczeniem). Dysponując przebiegiem współ-czynnika w funkcji parametrów klimatu, w następnym etapie wyznaczono wartość współczynnika konwersji promieniowania słonecznego w ciepło zmagazynowane w obiekcie. Obydwa parametry (współczynnik przenikania ciepła oraz konwersji promieniowania słonecznego) wyliczono z równania bilansu ciepła, w którym porównano zmianę energii zmagazynowanej wewnątrz obiektu ze stratami ciepła przez osłonę (dla przenikania ciepła) oraz zyskiem (w przypadku konwersji promieniowania słonecznego). Dla uzyskanych wartości, korzystając z procedury estymacji nieliniowej (metodą quasi-Newtona przy zachowanym współczynniku zbieżności 0,001) znaleziono zmienność obydwu współczynników w funkcji łatwo mierzalnych parametrów klimatu wewnątrz i na zewnątrz obiektu. W badanych warunkach, średnia wartość współczynnika przenikania ciepła przez osłonę była równa 5,32 W·m-2·K-1, zaś współczynnika konwersji promieniowania słonecznego w ciepło wyniosła 0,36. Znalezione wartości i ich przebieg od parametrów klimatu wewnątrz i na zewnątrz obiektu można wykorzystać do sterowania ilością dostarczanego ciepła oraz położeniem wietrzników.
2
Content available Multifrequency wideband sonar array
Elminowicz A., Lis W., Zajączkowski L.
Hydroacoustics
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2012
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Vol. 15
33-38
EN
This paper describes of new approach to Multifrequency Wideband Arrays (MWA), applied piezocomposite technologies of the array elements. MWA operating in transmitting (Tx) and receiving (Rx) mode on two or three bands, requires state-of-the-art technology and efficient array designing than conventional array in which separate arrays for every band or even separate Tx and Rx transducers/arrays are used. The new piezocomposite elements are designed at OBR Centrum Techniki Morskiej S.A., manufactured by Materials Systems Inc. (Littleton, USA) and tested at the cooperation with Gdansk University of Technology. The article presents research and development work at the multifrequency wideband piezocomposite arrays elements. An example of dual frequency wideband Tx/Rx array with design parameters and its implementation for the dual frequency wideband sonar will be presented. The results of array elements measurements: TVR, RVS, Impedance and Phase versus frequency from 50 kHz to 500 kHz as well as beam patterns, will be also presented.
3
Content available A spice equivalent circuit for modeling the performance of dual frequency echo-sounder
Moszynski M., Lis W.
Hydroacoustics
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2011
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Vol. 14
165-170
EN
The paper presents novel network equivalent circuit of piezoceramic circular disc transducer that takes into account thickness and radial mode of vibrations. The starting point of the analysis is 4-port description of circular disc element representing the solution of wave equation set in radial and thickness directions. The approximate solution for harmonic case is represented in the form of 4x4 matrix, which is synthesized and implemented in circuit analysis software. The network is extended with acoustical port that allows for pressure calculations in the similar manner as when measuring echo-sounder transmitting and receiving parameters. The model is especially useful for simulating complete electronic circuit of dual frequency echo-sounders based on single circular disc transducer.
4
Content available Broadband LFM signal source for a module-based diver detection sonar
Zachariasz K., Lis W., Elminowicz A.
Hydroacoustics
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2010
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Vol. 13
269-278
EN
A new approach to design of the diver detection sonar’s sounding pulse source is pre-sented. It is based on modules comprising 8 or 16 elements of the transducer grouped on the transmitting channel. The basic advantage of this solution is that it reduces significantly the number of group transmitters. The required output power and topology of the transmitters were determined through theoretical estimation and measurements in a four terminal network. Measurements were taken of the frequency characteristics in the transducer modules includ-ing the compensation system used. It is demonstrated that the source level is most irregular in the transducer under examination when the transducer’s voltage has a constant amplitude, i.e. with parallel compensation. It is also demonstrated that by appropriately selecting ele-ments for a series compensation of the transducer, the frequency characteristics becomes more regular and source level is increased at the extreme ends of the working bandwidth. The result is a compensated characteristics on the receiving side.
5
Content available An experimental study on transducer for the DDS technology demonstrator
Elminowicz A., Lis W., Męciński W.
Hydroacoustics
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2009
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Vol. 12
45-52
EN
R&D MTC has began designing and building the next generation wideband Diver Detection Sonar (DDS, with cylindrical multielement piezocomposite transducer. The paper will focus on key features of DDS technology demonstrator, with special attention on technologies of the transducer. The new transducer is designed at the cooperation with the producer of the transducer - Materials Systems Inc. (Littleton, USA), remainder hardware and software solutions are designed in R&D MTC. In this article specific theoretical and technological principles of the wideband cylindrical piezocomposite transducer will be presented. The implementation of the transducer to the wideband Diver Detection Sonar (DDS) will be described. The results of transducer measurements, transmitter modules, matching circuits modeling and examples of application will be also presented.
6
Content available Kompostowanie osadu ściekowego w Sierpcu
Siuta J., Dusik L., Lis W.
Inżynieria Ekologiczna
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2007
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Nr 19
97-105
PL
Kompostowanie osadu ściekowego, zawierającego 18% wody z udziałem słomy prowadzono w pryzmach doświadczalnych na powierzchni utwardzonej i zadaszonej. Zawartości organicznych i mineralnych składników w osadzie są bardzo korzystne do produkcji kompostu spełniającego wymogi prawa nawozowego. Nawozowe użytkowanie osadu wymaga biologicznej i odrowej sanitacji oraz przekształcenia konsystencji i mazistej do postaci ziemistej. Kompostowanie osadu z odpowiednim udziałem masy roślinnej spełnia powyższe wymogi. Mała zawartość suchej masy w osadzie sprawiła konieczność nadmiernego udziału słomy. W doświadczeniu zastosowano osad nie wapnowany i osad wapnowany z odpowiednimi udziałami słomy. Przebieg temperatury zniszczył chorobotwórcze organizmy. Kompost miał bardzo korzystne warunki nawozu organicznego.
EN
Composting of sewage sludge containing 18% of water with an admixture of straw was conducted in experimental prisms located on stabilized and sheltered surface. Contents of organic and mineral elements in the sludge are advantageous as regards the production of compost which meets the requirements of the fertilizer legislation. Applying the sludge for fertilization purposes necessitates its treatment in terms of biological and odour sanitation. Its consistence shall also be changed from a greasy- to earth like one. The composting of sludge together with an appropriate share of plant mass does meet the abovementioned requirements. As the dry mass content was low in the sludge the excess amount of straw was used. In the experiment, a non-limed and limed sludge was used with appropriate shares of straw. The temperature course has destroyed pathogenic microorganisms and the compost has ShOWl1 the quality of an organic fertilizer.
7
Content available Determining the impedance of ultrasonic transducers by the added elements method
Lis W., Schmidt J., Wojan Z.
Hydroacoustics
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2005
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Vol. 8
99-104
EN
There are a number of problems involved in measuring complex electrical impedance of ultrasonic transducers. This is because in the frequency function impedance tends to change values rapidly, in particular where resonances are involved. Measuring impedance using accurate bridge methods is a tedious and time-consuming process. While modern automated systems offer shorter test periods and high accuracy, they are very costly. This is why the project aims to implement new methods for computing impedance without these limitations. The article proposes a new, simplified method for measuring the electrical impedance of ultrasonic transducers. In the method complex impedance is calculated from results of two measurements of the transducer’s impedance magnitude only: with the known reactance and without it. To demonstrate the practicality of this method the authors included in the article the value of complex electrical impedance computed using the method and compared these with the results of measurements taken with an automated typical measurement system.
8
Content available remote Analiza skuteczności oczyszczania ścieków obciążonych dużym ładunkiem zanieczyszczeń browarniczych w oczyszczalni w Sierpcu
Wochowska D., Jeznach J., Lis W.
Przegląd Naukowy Inżynieria i Kształtowanie Środowiska
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2004
|
Vol. 13, No. 2
106--114
EN
The paper presents the characteristic of the sewage treatment plant in Sierpc and the study analysis of the effecctiveness of pollutant removal from sewage with great load of brewery pollutant. We performed analysis of study: the flow of sewage in 1999-2003, concentrations and load parametres of pollutions (BZT5, ChZT, nitrogen, phosphorus and suspension) contained in sewage discharge and supply, reduction of concentration and reduction of load of all the parameters in 1999-2003.
9
Content available Measuring the impedance of ultrasonic transducers
Lis W., Schmidt J.
Hydroacoustics
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2004
|
Vol. 7
143-148
EN
For ultrasonic transducers whose impedance is usually highly variable with frequency, impedance measurement is quite difficult. Cheap and easy devices which are currently available are not suitable for this purpose. Expensive scientific devices are known to be used; usually, they are designed for such measurements in a wide frequency band, from acoustic to microwave range. Simpler and cheaper devices with a narrower band are not commercially available. For hydroacoustic applications, the frequency range may be reduced to 1MHz or even 250 kHz in most cases. This article discusses the possibilities of building a simple and cheap automated system of measuring electric impedance of ultrasonic transducers used in hydroacoustics. The presented results are based on the concept of using a digital oscilloscope as the basic tool for measuring the impedance magnitude and phase. The results have been verified in the original measurement system.
10
Content available remote Analiza parametrów techniczno-eksploatacyjnych Miejskiej Oczyszczalni Ścieków w Sierpcu
Wochowska D., Jeznach J., Lis W.
Przegląd Naukowy Inżynieria i Kształtowanie Środowiska
|
2003
|
Vol. 12, No. 1
66--70
EN
The paper presents the characteristic of the sewage-treatment plant in Sierpc. We performed the cycle of thorough study in the sewage treatment plant: the flow of sewage in 1999-2002, concentrations and load parameters: BZT5, ChZT, nitrogen, phosphorus and suspension contained in sewage discharge and supply, reduction of concentration and reduction of load of all the parameters.
11
Content available The use of numerical methods for the analysis of phase phenomena in multi-element antennas
Lis W., Moszyński M.
Hydroacoustics
|
2003
|
Vol. 6
215--220
EN
The article describes an analysis of the effects of mutual impedance on the phase of multi-element antenna signals. The calculations were made using a substitute model of a Mason ultrasonic transducer. The effects of self and mutual impedance on the phase of multielement antenna signals were considered.
12
Badania diagnostyczne stawu skroniowo żuchwowego wybranej grupy pacjentów metodami akustycznymi
Lis W., Schmidt J., Zedler A., Zienkiewicz J.
Prace Naukowe Instytutu Telekomunikacji i Akustyki Politechniki Wrocławskiej. Konferencje
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2001
|
Vol. 83, nr 27
337-340
PL
Artykuł prezentuje kolejne osiągnięcia w dziedzinie poszukiwania istotnych cech sygnału akustycznego emitowanego przez badany staw skroniowo żuchwowy świadczących o jego stanie patologicznym. Fakt trudnego diagnozowania stawów uniemożliwia jednoznaczną korelację zarejestrowanych dźwięków z stanem chorobowym stawu. Jedyny rozsądnym rozwiązaniem wydaje się tu prowadzenie szeregu badań umożliwiających weryfikację wyników badań na drodze statystycznej z zastosowaniem współczesnych metod akwizycji i przetwarzania sygnału , W artykule opisano wyniki badań grupy pacjentów ze zróżnicowanymi dolegliwościami. Wyodrębniono tu 2 grupy rozpoznanych typowymi badaniami (wywiad i dokładne oględziny) patologii i schorzeń. Jako narzędzia rozpoznawania patologii wykorzystano klasyfikator w postaci trzy warstwowej sieci neuronowej. Uzyskane wyniki badań opublikowane w artykule potwierdzają przydatność zarówno samej metody akustycznego nasłuchu dźwięków emitowanych przez badane stawy jak i sposobu akwizycji i przetwarzania rejestrowanych sygnałów.
EN
Themporomandibular joints of the young people group was investigated using acoustic method. Closed age allows to create the representative shape of acoustic signal emitted by tmj. characteristic for healthy people. Used in system modern method of signal process and neural network technique can make more correct diagnosis. The method allows increasing subjective factor during medical examination.
13
Content available Microcontroller driven miniaturized digital depth sounder
Stepnowski A., Moszyński M., Postawka I., Lis W.
Hydroacoustics
|
2001
|
Vol. 4
221--224
EN
A miniaturized autonomous digital depth. sounder was developed for automatic storing and recording of sea bottom depth, along with communication to various marine equipment, (chart plotter, GPS) using NMEA 0183 protocol. The analog part of the sounder consists of the miniature HEXFET transmitter and the one chip double opamp receiver. The digital part constitutes the PIC microcontroller, with a built-in analog-to-digital converter (ADC) and universal asynchronous transmitter (UART). Such an. architecture allows sampling and storing the echo in compressed form in PIC's RAM memory. The UART allows transmission of the data acquired by the sounder between successive pings, via the serial line. The sounder software provides bottom tracking procedure, which can be remotely set up and reconfigured by operator. The sounder design is now under commercialization in C-MAP Group in Italy.
14
Content available remote Semi-automatic detection of cartographic objects in digital images
Lis W., Kasprzak W.
Machine Graphics and Vision
|
2000
|
Vol. 9, No. 1/2
447-452
EN
A computer system for semi-automatic detection of specific 2-D objects in digital images of cartographic maps is presentad. The system design combines image analysis methods with computer graphics and data base technologies. The purpose of this application system is to speed up the work of human specialist, to increase its efficiency and to transform cartographic maps into a symbolic, vector-based shape, i. e. to represent them in a general purpose data base. The system consists of three main modules: image analysis, graphic editor and data base administration. Up to now the object types being detected are: roads, cities, textured areas and some characteristic signs.
15
Content available High resolution methods of the analysis of acoustic signals in medicine
Lis W., Schmidt J.
Hydroacoustics
|
1999
|
Vol. 2
335--340
EN
The paper describes an analysis of the possible parametric methods used to estimate the spectrum of short acoustic signals of law oscillations. These kinds of signals often appear in acoustic waves emitted by the temporomandibular joint as it moves [1-2,5]. There is reason to suppose that the frequency which is characteristic of these oscillations could be an essential parameter confirming the pathology of the joint under examination. The measurement of low oscillations is difficult and not accurate, especially when nonparametric methods are used. The paper presents the results of analysis of a simulated short oscillating pulse using the DFT non-parametric method and the parametric method of linear prediction, using Burg algorithm. Finally, results of patient analysis are given, using the FFT and parametric methods.
16
Content available remote Ultrasonic transducer for the reception of acoustic emission signals of the temporomandibular joint
Salomon R., Lis W., Zienkiewicz J.
Archives of Acoustics
|
1999
|
Vol. 24, no. 3
331-364
EN
Auscultation and analysis of acoustic signals emitted by the human body are widely used in medical diagnosing. Acoustic signals are also emitted by joints, including the temporomandibular joint, which is the subject of this paper. A system was developed to receive, record, process and display the signals emitted by this particular joint. The article presents an essential fragment of the system, namely a special ultrasonic transducer designed to receive acoustic signals emitted by the temporomandibular joint. At first, the particular requirements were established in the area of the parameters and functions of the transducer. Following that, a technological solution was proposed. Next, a model of the transducer was analysed using the difference equation method with continuous time. The solution of these equations is the pulse response of the transducer and in the frequency domain, it is the shift function. These functions were used for an in-depth analysis of the effects of the transducer's construction on its parameters and values. Based on these findings, a methodology of the design of the transducer was developed. The transducer was designed and built according to the methodology. It was subsequently studied in detail. The results of the study have confirmed that the method of the analysis and the design were correct. Finally, the article presents some examples of real signals of acoustic emission of the temporomandibular joint as they were received by the ultrasonic transducer built in the course of the work.
17
Content available remote Studying the acoustic emission of the temporomandibular joint
Lis W., Salomon R., Zienkiewicz J.
Archives of Acoustics
|
1999
|
Vol. 24, no. 3
303-318
EN
The method of acoustic emission is widely used for testing the strength of materials and in passive underwater acoustics. Recently in the field of medicine, acoustic emission signals received in the traditional phonendoscope method are recorded and processed using advanced electronic technology. Presented in this paper is an example of this work. It is a system that tests the acoustic emission of the temporomandibular joint which when in a pathological state seriously impairs important physiological functions of man. The presented system receives and records acoustic signals emitted by the joint. This is synchronised with the registration of the jaw displacement. Based on that, parameters and characteristics of acoustic emission signals which could indicate a specific disease of the joint are determined. In the research to date the focus has been on determining the statistical distributions of root-mean-square and maximal values of the signals and the current spectrums linked to the movement of the mandible. Clinical tests carried out at the Clinic of Maxillofacial Surgery at the Medical Academy of Gdańsk have provided preliminary confirmation of the usefulness of the system for diagnostic functions. The tests are being continued and are systematically contributing to the collection of signals and cases. This in turn is the condition of progress of continued work on the use of acoustic emission in diagnosing the temporomandibular joint.
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