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Open access

Tomasz Muszyński and Sławomir Marcin Kozieł

Abstract

Two-dimensional numerical investigations of the fluid flow and heat transfer have been carried out for the laminar flow of the louvered fin-plate heat exchanger, designed to work as an air-source heat pump evaporator. The transferred heat and the pressure drop predicted by simulation have been compared with the corresponding experimental data taken from the literature. Two dimensional analyses of the louvered fins with varying geometry have been conducted. Simulations have been performed for different geometries with varying louver pitch, louver angle and different louver blade number. Constant inlet air temperature and varying velocity ranging from 2 to 8 m/s was assumed in the numerical experiments. The air-side performance is evaluated by calculating the temperature and the pressure drop ratio. Efficiency curves are obtained that can be used to select optimum louver geometry for the selected inlet parameters. A total of 363 different cases of various fin geometry for 7 different air velocities were investigated. The maximum heat transfer improvement interpreted in terms of the maximum efficiency has been obtained for the louver angle of 16 ° and the louver pitch of 1.35 mm. The presented results indicate that varying louver geometry might be a convenient way of enhancing performance of heat exchangers.

Open access

Tomasz Grenda, Elżbieta Kukier, Magdalena Goldsztejn, Krzysztof Kwiatek and Nina Kozieł

Abstract

As the test material mink feed with natural microflora was used. The analyses were conducted using Wrzosek and TPGY broth media, and Willis–Hobbs and Zeissler differential agar media. Wrzosek, Willis–Hobbs, and Zeissler media are described in Polish Standards approved by the National Standards Body in Poland and routinely used in detection of anaerobic bacteria in Poland. Detection and identification of C. botulinum was performed with a previously validated real-time PCR method based on ntnh gene detection, which is common in all C. botulinum toxotypes. The use of Wrzosek broth and Zeissler agar in routine analyses for detection and identification of C. botulinum was ineffective and limited. The obtained results showed the highest culturing process effectiveness in TPGY broth with 72 h incubation at 30°C and isolation on Willis–Hobbs agar. The real-time PCR method based on ntnh gene detection used in this study could be utilised as a supplementary tool to the mouse lethality assay.

Open access

Jakub Kuchinka, Łukasz Nawacki, Piotr Bryk, Jarosław Matykiewicz, Iwona Wawrzycka, Dorota Kozieł, Tomasz Rogula and Stanisław Głuszek

Abstract

Obesity, at present, seems to be a very serious health problem all over the world. The surgery is said to be the most successful treatment of obesity. With the increase in the quantity of conducted bariatric procedures, the number of revision treatments increases as well.

The aim of the study was to analyze the indications, results and complications after repeated bariatric surgeries.

Material and methods. The repeated bariatric procedures performed in 2009-2015 have been retrospectively analyzed. The endpoint of the study was the evaluation of early surgical treatment results-up to 30th day after repeated surgery.

Results. Overall, amongs 103 obese patients with a BMI over 35 kg / m2, qualified for bariatric treatment 7 revision surgeries were conducted (6.8%). Two operations were carried out by laporotomy, other by laparoscopy. In the study group, neither any deaths were noted in perioperative period nor life-threatening complications. The frequency of complications-Surgical site infection and bleeding from the staple lines of stapler in the study group appeared to be 28.6%.

Conclusions. Qualification for repeated bariatric surgeries should be based on a thorough analysis of the condition of the patient, previous outcome of the bariatric treatment: evaluation of weight loss as well as possible complications of the original surgery.

Open access

Sebastian Zduński, Witold Rongies, Marcin Ziółkowski, Tomasz Kozieł, Piotr Kazimierski, Rafał Hałaj and Janusz Sierdziński

Abstract

Introduction: In the majority of cases, anterior cruciate ligament (ACL) injuries require specialist surgical and physiotherapeutic treatment. The fact that the patient regains a full range of flexion and extension in the knee joint as well as the reduction or elimination of pain is a significant determinant of successful physiotherapy. Material and methods: The study included 72 randomly selected individuals with a complete ACL tear who were qualified for its surgical reconstruction. The research group included 37 patients aged 18-60 (mean age 37±10.3 years). All the participants from this group underwent physiotherapy based on recognised schemes of rehabilitation and performed for 4 weeks before the reconstruction surgery. The control group included 35 patients aged 18-60 (mean age 34±10.0 years) who did not undergo any presurgical physiotherapy programme. Results: Both in the research group and in the control group, subsequent measurements revealed a statistically significant improvement in the range of flexion and extension (p<0.05). Statistical analysis revealed a significantly better extension 1 week and 6 weeks after the ACL reconstruction (p<0.05) in the research group. Statistically significant differences in the level of pain in patients from both groups were noted in subsequent measurements (p<0.05). Also, a statistically significant difference concerning pain assessment 12 weeks after the reconstruction was noted in the research group (p<0.05). Conclusions: A quicker recovery of the range of extension in the operated knee joint and lower intensity of pain in the final measurement noted in the research group may indicate a certain therapeutic value of presurgical physiotherapy.