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  • Author: Mirosław Kozłowski x
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Open access

Joanna Rymarczyk and Mirosław Kozłowski

Abstract

In this paper a method of determination of Pd in a carbon-palladium film (C-Pd film) deposited on a quartz substrate is presented. This method is based on energy dispersive X-ray spectroscopy (EDX) and all experiments were performed using a scanning electron microscope (SEM) equipped with EDX system. Qualitative and quantitative analyses were carried out for C-Pd films prepared by PVD method in different technological conditions. It was shown that results of the experiments depended on the structural model, film thickness and electron beam energy used for Pd content calculation.

This method enabled us to conclude on the homogeneity of palladium distribution in the whole volume of carbonaceous matrix, depending on the parameters of PVD process. Additionally, these studies showed that a different palladium concentration in C-Pd films had a significant impact on their topography and morphology.

Open access

Michał Kozłowski, Mirosław Szczepkowski, Krzysztof Wunderlich, Bożena Szczepkowska and Iwona Piotrowska

Abstract

The experiment examined the possibility of rearing juvenile pikeperch, Sander lucioperca (L.) in polyculture with sterlet Acipenser ruthenus L. in a recirculating system. Three variants of pikeperch rearing were tested: monoculture (group S), with the addition of sterlet at 10% (group S10) and 20% (group S20) of the initial pikeperch biomass. After 56 days of rearing, no differences in the growth rates or survival of the pikeperch were noted. The value of the feed conversion ratio in the monoculture group was 1.19 and was significantly statistically higher than in the polyculture groups, the values of which were 0.84 (S10) and 0.74 (S20). The mean oxygen consumption and ammonia excretion values did not differ significantly statistically among the studied groups. Including the sterlet stock with the pikeperch permitted obtaining the additional value of the sterlet biomass using the same quantity of feed. Additionally, the inclusion of sterlet decreased the labor intensity of pikeperch rearing since the tanks did not need cleaning as frequently.

Open access

M. Kozłowski, E. Czerwosz, J. Radomska, K. Sobczak and P.A. Dłużewski

Abstract

Properties of palladium nanograins obtained by sedimentation of a soluted C-Pd film prepared by PVD method are presented. These properties were studied using SEM and TEM methods. Dissolved films were prepared by PVD method and after dissolving, they were fractionated to obtain different parts classified with palladium nanograins diameters. Several classes of diameters were determined: below 20 nm, between 20 and 100 nm and above 100 nm. The defects and triple junction were observed. Multishell carbonaceous structures were found in the big and medium size Pd nanograins.

Open access

Joanna Rymarczyk, Elżbieta Czerwosz, Ryszard Diduszko and Mirosław Kozłowski

Abstract

The mechanisms of thermal decomposition of evaporated material during Physical Vapor Deposition (PVD) process depend on the kind of evaporated material. Such parameters of PVD process as deposition rate, source temperature and deposition time should be carefully selected taking into account the properties of material. Deposited films can span the range of chemical compositions based on the source materials. The nanostructural carbon films in form of palladium nanograins embedded in various carbonaceous matrixes were obtained by thermal evaporation during PVD process from two separated sources containing C60 fullerite and palladium acetate, both in a form of powder. The evaporation was realized by resistive heating of sources under a dynamic vacuum of 10-3 Pa. The influence of decomposition path of evaporated materials on the film structure has been discussed. Prepared C-Pd films were characterized using thermo-gravimetric method, differential thermal analysis, infrared spectroscopy and X-ray diffraction. The influence of decomposition of Pd acetate and fullerite on the final film structure was also shown.

Open access

Izabela Stępińska, Elżbieta Czerwosz, Mirosław Kozłowski, Halina Wronka and Piotr Dłużewski

Abstract

Field emission from materials at high electric fields can be associated with unfavorable or even destructive effect on the surface of the investigated cathode. The impact of high voltage electric power supply causes locally very strong electric fields focusing on the cathode surface. It causes a number of phenomena, which can adversely affect the morphology and the structure of the cathode material. Such a phenomenon is, for example, peeling of an emissive layer from the substrate or its burnout. It results in tearing of the layer and a decrease or loss of its ability to electrons emission. The cold cathodes in a form of CNT films with various CNTs superficial distribution are obtained by physical vapor deposition followed by chemical vapor deposition. CNTs are catalyzed in pyrolytic process with xylene (CVD), by Ni in a form of nanograins (few nm in size) placed in carbonaceous matrix. These films are built of emissive CNTs - carbonaceous film deposited on different substrates. In this work, the morphology and topography of superficial changes resulting from external electric field in such films were investigated.

Open access

Joanna Rymarczyk, Elżbieta Czerwosz, Mirosław Kozłowski, Piotr Dłużewski and Wojciech Kowalski

Abstract

The paper describes the preparation and characteristics of films composed of Pd nanograins placed in carbonaceous matrix. Films were obtained in PVD (Physical Vapor Deposition) process from two sources containing: the first one - fullerene powder and the second one - palladium acetate. The topographical, morphological and structural changes due to different parameters of PVD process were studied with the use of Atomic Force Microscopy and Scanning Electron Microscopy, whereas the structure was studied with the application of the Transmission Electron Microscopy and Fourier Transform Infrared Spectroscopy methods. It was shown that topographical changes are connected with the decomposition ratio of Pd acetate as well as the form of carbonaceous matrix formed due to this decomposition. Palladium nanograins found in all films exhibit the fcc structure type and their diameter changes from 2 nm to 40 nm depending on the PVD process parameters.

Open access

Mirosław Dziekiewicz, Tomasz Markiewicz, Wojciech Kozłowski and Marek Maruszyński

Abstract

The study presented an approach to the morphometric image of atherosclerotic lesions of the final segment of the abdominal aorta, femoral and iliac arteries, considering possible endovascular intervention. The evaluation of these arteries is very important, because they are often used as a point of access for endovascular procedures performed on the peripheral arteries, or within the thoracic and abdominal aorta and its branches, as well as coronary arteries.

The aim of the study was to determine morphometric measurements describing the atherosclerotic lesions, including the methodology of their surgical interpretation.

Material and methods. The study group comprised 128 tomograms of patients qualified for surgery. An algorithm based on the mathematical morphology was designed to track the vessels, starting from the division of the common femoral artery, and ending at the bifurcation of the abdominal aorta. We proposed a set of numerical measurements of the observed arterial changes.

Results and conclusions. We analysed 128 tomograms with a 94.5% efficiency, and with the assessment accuracy of the degree of lumen reduction (MAE- 1.5%). We observed much higher measurement values of local tortuosity of the atherosclerotic arteries (0.3 - 1 radians), as compared to their anatomical course in a healthy subject (0 - 0.2 radians). The presented method can be a very accurate and useful tool in the numerical analysis of the lumen distribution of the arteries and atherosclerosis, dedicated to surgeons elaborating management strategies.

Open access

Kamil Pudło, Alan Błotniak, Tomasz Skoczylas, Andrzej Dąbrowski, Andrzej Szawłowski, Mirosław Kozłowski, Paweł Lampe and Grzegorz Wallner

Abstract

Among many various factors affecting the outcome of cancer treatment one can distinguish patient, tumor- and treatment-related factors. The association of patient-related factors and results of a combined modality therapy of esophageal cancer has not been extensively explored.

The aim of the study was to analyze the impact of patient-related constitutional and environmental factors on early results of combined modality therapy of esophageal squamous cell carcinoma.

Material and methods. We retrospectively analyzed prospectively collected data of 84 patients with esophageal cancer randomly assigned to a combined modality treatment. We evaluated the relationship between early outcome of neoadjuvant therapy (overall toxic events, serious toxic events, treatment-related mortality, clinical and pathological response to the treatment) or surgical treatment (postoperative morbidity, mortality and curative resections – R0) and constitutional (age, gender, height, body mass index, Karnofski Performance Status – KPS, blood type) or environmental (inhabitation, smoking duration and intensity, frequency and amount of alcohol consumption and occupational exposure) patient-related factors.

Results. Significantly more neoadjuvant therapy related deaths were found in patients with KPS 70-80 (p=0.0016). Interestingly, significantly more toxic events (p=0.0034) after neoadjuvant therapy and a higher postoperative morbidity rate (p=0.0293) were observed in nonsmokers. Similarly, significantly more toxic events (p=0.0029) after neoadjuvant therapy and a higher postoperative mortality rate (p=0.0405) were found in light drinkers.

Conclusions. Smoking and consumption of excessive amount of alcohol may attenuate toxic effect of neoadiuvant and surgical therapy in patients treated due to esophageal cancer. The information regarding the mentioned above addictions should not result in giving up an attempt to provide a curative treatment.

Open access

Izabela Stępinska, Mirosław Kozłowski, Joanna Radomska, Halina Wronka, Elżbieta Czerwosz and Kamil Sobczak

Abstract

In this paper various types of films made of carbon nanotubes (CNTs) are presented. These films were prepared on different substrates (Al2O3, Si n-type) by the two-step method. The two-step method consists of physical vapor deposition step, followed by chemical vapor deposition step (PVD/CVD). Parameters of PVD process were the same for all initial films, while the duration times of the second step - the CVD process, were different (15, 30 min.). Prepared films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and field emission (FE) measurements. The I-E and F-N characteristics of electron emission were discussed in terms of various forms of CNT films. The value of threshold electric field ranged from few V/μm (for CNT dispersed rarely on the surface of the film deposited on Si) up to ~20 V/μm (for Al2O3 substrate).

Open access

Tomasz Markiewicz, Mirosław Dziekiewicz, Marek Maruszyński, Romana Bogusławska-Walecka and Wojciech Kozłowski

Abstract

In this paper the authors raise the issue of automatic discrimination of atherosclerotic plaques within an artery lumen based on numerical and statistical thresholding of Computerized Tomography Angiographic (CTA) images and their advanced dimensioning as a support for preoperative vessel assessment. For the study, a set of tomograms of the aorta, as well as the ilio-femoral and femoral arteries were examined. In each case a sequence of about 130-480 images of the artery cutoff planes were analyzed prior to their segmentation based on morphological image transformation. A crucial step in the staging of atherosclerotic alteration is recognition of the plaque in the CTA image. To solve this problem, statistical and linear fitting methods, including the least-squares approximation by polynomial and spline polynomial functions, as well as the error fitting function were used. Also, new descriptors of atherosclerotic changes, such as the lumen decrease factor, the circumference occupancy factor, and the convex plaque area factor, are proposed as a means of facilitating preoperative vessel examination. Finally, ways to reduce the computational time are discussed. The proposed methods can be very useful for automatic quantification of atherosclerotic changes visualized by CTA imaging.