Search Results

You are looking at 1 - 10 of 24 items for

  • Author: Andrzej Nowak x
Clear All Modify Search
Open access

Andrzej Felski and Aleksander Nowak

Abstract

Any SBAS system, as soon as it is permanently monitored by Earth stations, should deliver to the users correct information about quality of the augmented system. According to many sources of information, among them observations of authors, present accuracy of EGNOS service has accuracy about 1,5m (95%), but availability of the service is still controversial. First of all the quality of the system is guaranteed only inside the border of the system coverage which still do not affect all territory of European Union, however observed accuracy at times is better outside this area than next door to the RIMS station. In addition there are evidences that availability has random character and essential differences as well as lack of correlation of this parameter in the different point of observations has been observed. So in author’s opinion Local Monitoring of EGNOS service can contribute to better confidence of local users, especially in critical operations, like for example berthing of big ships or landing operations with EGNOS procedures. The example of EGNOS monitor which is working in real time and performed by the authors will be presented

Open access

Andrzej Felski, Aleksander Nowak and Tomasz Woźniak

Accuracy and Availability of Egnos - Results of Observations

According to SBAS concept the user should receive timely the correct information about the system integrity and corrections to the pseudoranges measurements, which leads to better accuracy of coordinates. In theory the whole system is permanently monitored by RIMS stations, so it is impossible to deliver the faulty information to the user. The quality of the system is guaranteed inside the border of the system coverage however in the east part of Poland lower accuracy and availability of the system is still observed. This was the impulse to start an observation and analysis of real accuracy and availability of EGNOS service in the context of support air-operations in local airports and as the supplementation in hydrographic operations on the Polish Exclusive Zone.

A registration has been conducted on three PANSA stations situated on airports in Warsaw, Krakow and Rzeszow and on PNA station in Gdynia. Measurements on PANSA stations have been completed permanently during each whole month up to end of September 2011. These stations are established on Septentrio PolaRx2e receivers and have been engaged into EGNOS Data Collection Network performed by EUROCONTROL. The advantage of these registrations is the uniformity of receivers. Apart from these registrations additional measurements in Gdynia have been provided with different receivers, mainly dedicated sea-navigation: CSI Wireless 1, NOVATEL OEMV, Sperry Navistar, Crescent V-100 and R110 as well as Magellan FX420.

The main object of analyses was the accuracy and availability of EGNOS service in each point and for different receivers. Accuracy has been analyzed separately for each coordinate. Finally the temporarily and spatial correlations of coordinates, its availability and accuracy has been investigated.

The findings prove that present accuracy of EGNOS service is about 1,5m (95%), but availability of the service is controversial. The accuracy of present EGNOS service meets the parameters of APV I and even APV II requirements, as well as any maritime and hydrography needs. However introducing this service into the practice demands better availability, because the gaps in receiving the proper information from the system appear too often and are too long at the moment. Additionally it was noticed very random character of availability and no correlation of this parameter in the different point of observations. In spite the correct EGNOS work the accuracy of the coordinates is not predictable in the local conditions. So in authors' opinion Local Airport Monitoring should be deployed if EGNOS would have to serve to the local airport service.

Open access

Damian Nowak, Andrzej Stafiniak and Andrzej Dziedzic

Abstract

Studies on electromigration phenomenon in thick-film structures on alumina and LTCC substrates are presented in this paper. The effects of storage of Au and Ag electrode patterns in temperature range up to 300 °C under voltage bias were examined. The leakage characteristics of electrodes with 100 μm spacing at 50 V dc bias as a function of time and temperature are presented and analyzed. Scanning electron microscope (SEM) equipped with the energy-dispersive X-ray spectroscopy (EDX) detector was applied for determination of metal ions transport. Test structures with Au-based conductive material are much more resistant to electromigration than Ag-based layers.

Open access

Andrzej Nowak, Maciej J. Nowak and Krystyna Cybulska

Abstract

Microorganisms, usually invisible for us, accompany us always and everywhere. Often we do not realize how decisive its impact on our lives is, how much we use their presence, which of our troubles are the result of their actions, and also how surprising effects result from their activity. Microorganisms also very often play a decisive role in the development of societies, politics and history. One of the most spectacular interventions of micro-organisms in human history include the example of a false “oil fever” that exploded in Australia in the second half of the nineteenth century. It was even more significant to redirect Europe's history in the new direction as a result of the “black death” epidemic in the fourteenth century. Microorganisms have created social conditions for the transition to the next epoch - renaissance, which forms the basis of today's shape. Because of the microorganisms J.F. Kennedy could have been in the 1960 President of the United States of America and to direct her development in the new direction and to stop Khrushchev's expansion into the second hemisphere. Microorganisms, not leaders and generals, won battles and wars. It was Rikketsia prowazeki, not the genius of the opponents, that broke Napoleon's power in Europe. Microorganisms fight disease, improving quality of life and prolonging its period. They allowed to control rabies and numerous infectious diseases. In the economy for the cause of microorganisms, powerful monopolies fell. Bacteria were also used to protect civilians in Poland during World War II. There are many similar stories to tell, stories in which microorganisms play an essential role. But would these stories be about microorganisms only? Or perhaps about people who were fascinated by the microscopic world of microbes discovered his secrets, meaning and ... beauty.

Open access

Andrzej Felski and Aleksander Nowak

ABSTRACT

Any SBAS system should deliver to the user corrections to pseudoranges as well as information about the system integrity. In theory, as soon as the system is permanently monitored by RIMS stations, it is impossible to deliver the fault information to the user. However many observations shows that accuracy of EGNOS service in the same time are different in different places, which shows the influence of local conditions on them. In addition evidences on possibilities in jamming or spoofing of GPS signals should be seriously taken into account. According to many sources of information, among them observations of authors, present accuracy of EGNOS service has better than declared. In fact EGNOS accuracy is about 1,5m (95%), but availability of the service happens still controversial and it has random character. According to reports essential differences as well as lack of correlation of this parameter in the different point of observations has been observed. So in author’s opinion Local Monitoring of EGNOS service can contribute to better confidence of local users, especially in critical operations, like for example berthing of big ships or in landing operations with EGNOS procedures. An example of such system which works in real time has been elaborated in Polish Naval Academy and will be presented.

Open access

Andrzej Jopkiewicz, Jacek Gawron and Stanisław Nowak

Abstract

Purpose. The aim of the study was to check whether and to what extent leisure-time physical activity and commuting activity constitute a factor differentiating physical fitness in a selected group of females and males aged 20-59 years. Methods. The study was performed in the Świętokrzyskie region of Poland in the spring of 2010. The sample included 1032 adults (517 females and 515 males) employed and at the same time completing extramural education or attending vocational improvement programs. Four age groups were delineated (20-29, 30-39, 40-49 and 50-59). A self-report questionnaire assessed physical activity level whereas physical fitness was determined by tests assessing handgrip strength, upper (dynamic) and lower (explosive) extremity strength, agility, hand movement speed, and endurance. Results. A significant relationship was found between leisure-time physical activity and all the performance-based measures in both females and males. With regard to commuting activity, statistically significant relationships were observed only in the females with regard to handgrip strength, lower extremity strength and endurance. Conclusions. A significant positive relationship between leisure-time physical activity and physical fitness was demonstrated in both females and males aged 20-59 years while commuting activity should significant correlations only in females.

Open access

Andrzej Mastalerz, Ewa Nowak, Iwona Palczewska and Ewa Kalka

Maximal Grip Force During Holding A Cylindrical Handle with Different Diameters

Purpose. The purpose of the study was to estimate the effects of cylindrical handle diameter and handle position on maximal grip force in young males and females. Basic procedures. The maximal voluntary grip force perpendicular to the surface of the handle was estimated using a glove with 320 sensors (Tekscan, USA - GripTM System). Individual digit and palm forces were studied. Different handle diameters (20, 30, 40 and 50 mm) and handle positions (vertical, natural - vertical handle with 12 deg of ulnar deviation of the hand, and horizontal) were applied during measurement. Main findings. Using handles and hand tools frequently leads to the feeling of discomfort in daily life. In a longer term, using improper handles and hand tools may also cause musculoskeletal disorders. Poor wrist positioning and handle diameter can diminish grip strength. The ideal diameter and wrist position during holding a tool handle was determined for males and females using maximal grip strength measurements. The obtained results showed that a tool handle diameter of 20 to 30 mm is optimal for the general population. Further research should be carried out to estimate the impact of wrist positioning in the elderly. Conclusions. The handle positioning is not a significant factor influencing hand grip force capabilities for young men and women. The grip force of three digits did not significantly vary for different handle positions used in the study. The optimal handle diameter for maximal grip force was estimated to be between 20 and 30 mm, and the diameter was larger for men. On the basis of results for individual digits the 30 mm diameter was chosen as optimal for both sexes.

Open access

Szymon Sarbak, Melania Kujawa, Hanna Jurga-Nowak and Andrzej Dobek

Abstract

The effect of 0.01-1 M sodium ions on the conformation of the folded brewer’s yeast tRNAPhe was examined by circular dichroism method in the region 200-350 nm. The minimum peak at about 210 nm for tRNA solution with 50 mM sodium chloride showed a decrease in magnitude by 26-30% in comparison to that recorded for the solution of higher NaCl content. The depths of the peaks at 225 nm and 233 nm for two solutions with the lowest sodium chloride concentrations (cNaCl = 10mM, cNaCl = 50mM) were changed by 3-10% relative to the those in the spectra of other samples, for the 260 nm maximum peak a decrease in height was 21-25%. In the region 300-350 nm no significant difference was observed. The results point to a strong relationship between concentration of sodium ions and stabilization process of secondary and tertiary tRNA structure, which indicates the influence of sodium ions on stacking and base-pairing interactions.

Open access

Iwona Adamiec-Wójcik, Andrzej Nowak and Stanisław Wojciech

Abstract

Dry electrostatic precipitators (ESPs) are widely used for purification of exhaust gases in industrial applications. Maintenance of their high efficiency depends primarily on periodical cleaning of the collecting electrodes (CEs). Dust removal (regeneration of CEs) is realized by inducing periodical vibrations of the electrodes. The paper presents results of vibration modelling of a system of CEs; the results were obtained by means of the finite element method, the hybrid finite element method, the finite strip method and a model formulated using Abaqus. Numerical results are compared with those obtained from experimental measurements. Conclusions concerning numerical effectiveness and exactness of the methods are formulated and reasons for differences are discussed.

Open access

Iwona Adamiec-Wójcik, Andrzej Nowak and Stanisław Wojciech

Abstract

The rigid finite element method (RFEM) has been used mainly for modelling systems with beam-like links. This paper deals with modelling of a single set of electrodes consisting of an upper beam with electrodes, which are shells with complicated shapes, and an anvil beam. Discretisation of the whole system, both the beams and the electrodes, is carried out by means of the rigid finite element method. The results of calculations concerned with free vibrations of the plates are compared with those obtained from a commercial package of the finite element method (FEM), while forced vibrations of the set of electrodes are compared with those obtained by means of the hybrid finite element method (HFEM) and experimental measurements obtained on a special test stand.