ZNANSTVENA ETIKA ZAGREBAČKIH STUDENATA Knežević, Lovro; Ježovita, Josip
Media, culture and public relations (Online),
09/2023, Volume:
14, Issue:
2
Journal Article
Peer reviewed
Open access
Ključne riječi znanstvena etika, profesionalne vrijednosti, etički upitna ponašanja, studenti Abstract Doubly researched, through professional values and ethically questionable behaviors, scientific ...ethics among students appears in the same way as in similar scientific research, but with certain differences and emphases specific to student life. The paper presents the results on scientific ethics, which were obtained using survey and interview methods. The results refer to the following research aims: (1) representation of professional scientific values and norms among Zagreb students; and (2) the level of perception of ethically questionable behavior among Zagreb students. The analysis showed that among the professional norms objectivity and precision stand out, and among the ethically questionable behaviors according to the respondents' perception, various forms of plagiarism, discrimination, and inadequate attribution of (co)authorship are most present. Keywords scientific ethics, professional values, ethically questionable behaviors, students Uvod S velikim promjenama koje su nastupile ili tek dolaze na području studiranja i znanstvene prakse javlja se mogućnost i potreba za odgovornim praćenjem tih procesa.
The reliability of marine propulsion systems depends on the reliability of several sub-systems of a diesel engine. The scavenge air system is one of the crucial sub-systems of the marine engine with ...a turbocharger as an essential component. In this paper, the failures of a turbocharger are analyzed through the fault tree analysis (FTA) method to estimate the reliability of the system and to predict the cause of failures. The quantitative method is used for assessing the probability of faults occurring in the turbocharger system. The main failures of a scavenge air sub-system, such as air filter blockage, compressor fouling, turbine fouling (exhaust side), cooler tube blockage and cooler air side blockage, are simulated on a Wärtsilä-Transas engine simulator for a marine two-stroke diesel engine. The results obtained through the simulation can provide improvement in the maintenance plan, reliability of the propulsion system and optimization of turbocharger operation during exploitation time.
This paper presents a method of adjusting and designing the maintenance scheme for the high-pressure fuel pumps of a slow-speed two-stroke marine engine, MAN 6S70MC-C. The maintenance database for ...the marine fuel system was obtained from the planned maintenance software, and covered a period of 11 years. During this period, 29 failures occurred that required corrective actions. Our methodology includes failure mode analysis, risk analysis, reliability calculation and maintenance interval adjustment. Each failure is described using a failure mode analysis, based on a combination of the mode and cause of failure. The objective of this study is to recommend a new preventive maintenance interval based on the exponential reliability results and the analysed maintenance data. The initial maintenance plan for each fuel pump was set to 8,000 running hours, whereas in the modified plan, it is recommended to set this to 4,000 hours. Our results show an increase in the system reliability from 60% to 95% when the new modified maintenance plan is applied. In addition, the results and the recommended initial maintenance schedule are validated based on three similar types of engine with the same fuel pump system. The new maintenance approach can reduce the risk of component failure, which will lead to increased reliability of the fuel pump system and the optimisation of maintenance costs.
Increasingly stringent environmental requirements for marine engines imposed by the International Maritime Organisation and the European Union require that marine engines have the lowest possible ...emissions of greenhouse and harmful exhaust gases into the atmosphere. In this research, exhaust gas emissions were measured on three Ro-Pax vessels sailing in the Adriatic Sea. Testo 350 Maritime exhaust gas analyser was used for monitoring the dry exhaust gas concentrations of CO2 and O2 in percentage, concentrations of CO and NOx in ppm and exhaust gas temperature in °C after the turbocharger at different engine loads. In order to compare and validate measured values, exhaust gas measurement data were also obtained from a Wartsila-Transas simulator model of a similar Ro-Pax vessel during the joint operation of the engine room and navigational simulators. All analysed main engines on three vessels had complete combustion processes in the cylinders with small differences which should be further investigated. Comparison of on board measured parameters with simulated parameters showed that significant fuel oil reduction per voyage could be accomplished by voyage and/or engine operation optimization procedures. Results of this analysis could be used for creating additional emission database and data-driven models for further analysis and improved estimation of exhaust gasses under various marine engine conditions. Additionally, the results could be useful to all interested parties in reducing the fuel oil consumption and emissions of greenhouse and harmful exhaust gases from vessels into the atmosphere.
The association between human papillomavirus (HPV) types and oral lesions has been shown in many studies. Considering the significance that HPV has in the development of malignant and potentially ...malignant disorders of the oral mucosa, the purpose of this study was to investigate the prevalence of HPV DNA in different oral lesions. In addition, we wanted to elucidate whether the HPV infection is associated predominantly with either the lesion or a particular anatomic site of the oral cavity.
The study included 246 subjects with different oral lesions, and 73 subjects with apparently healthy oral mucosa (controls). The oral lesions were classified according to their surface morphology and clinical diagnosis. The epithelial cells were collected with a cytobrush from different topographic sites in the oral cavity of the oral lesions and controls. The presence of HPV DNA was evaluated by consensus and type-specific primer-directed polymerase chain reaction. The HPV positivity was detected in 17.7% of oral lesions, significantly more than in apparently healthy mucosa (6.8%), with a higher presence in benign proliferative mucosal lesions (18.6%). High-risk HPV types were predominantly found in potentially malignant oral disorders (HPV16 in 4.3% and HPV31 in 3.4%), while benign proliferative lesions as well as healthy oral mucosa contained mainly undetermined HPV type (13.6 and 6.8%, respectively).
The distribution of positive HPV findings on the oral mucosa seems to be more associated with a particular anatomical site than the diagnosis itself. Samples taken from the vermilion border, labial commissures, and hard palate were most often HPV positive. Thus, topography plays a role in HPV prevalence findings in oral lesions. Because of the higher prevalence of the high-risk HPV types in potentially malignant oral disorders, these lesions need to be continuously controlled and treated.
The paper presents the initial case of a research of analysing maintenance interval adjustment in the shipping industry. This case is an example of the adjustment of the maintenance interval carried ...out by ship's crew on starting air compressor system. The example is found and followed through the records in the computerized Planned Maintenance System. Maintenance interval adjustment proposal and actual adjustment were carried out based on user's experience, after rechecking maintenance data and actual machinery condition, without theoretical approach or analysis. That process created new maintenance plan which is in use on the system for past ten years. Missing actions in the process, i.e. theoretical analysis of the initial and modified maintenance, are performed using the MA-CAD method with a modified reliability testing and are described in the paper. Results obtained by the theoretical analysis are compared with the requested and performed modification of the Maintenance Plan and a conclusion about performed action has been derived.
This paper presents an analysis of the low duty compressor for marine steam generators and its running conditions. The analysed low duty compressor was observed under three different running zones ...caused by a throttled flow towards main steam generators. All examples were explained according to real exploitation conditions. As the low duty compressor has the highest influence on the flame stability for the main steam generators while running, it is very important to observe the constant flow towards the main steam generators. Possible flow fluctuation implies instabilities which are explained in the article and the same have to be avoided in order to assure a reliable life span of the low duty compressor and smooth operation of the main steam generators. Furthermore, for preventing efficiency losses of a steam power plant, some methods for avoiding surge effects are emphasized and recommended.
The objective of this study was to determine differential expression of TFF1, TFF2 and TFF3 genes and proteins in breast tumor subtypes. In addition, we investigated the correlation between TFF genes ...within tumor subgroups, and TFF genes with clinical and pathologic characteristics of the tumor. Study group included 122 patients with surgically removed breast tumors. Samples were investigated using qRT-PCR and immunohistochemistry. TFF1 and TFF3 genes and proteins were expressed in breast tumors, while the levels of TFF2 gene and protein expression were very low or undetectable. TFF1 was significantly more expressed in benign tumors, while TFF3 was more expressed in malignant tumors. Gene and protein expression of both TFF1 and TFF3 was greater in lymph node-negative tumors, hormone positive tumors, tumors with moderate levels of Ki67 expression, and in grade II tumors. A strong positive correlation was found between TFF1 and TFF3 genes, and the expression of both negatively correlated with Ki67 and the level of tumor histologic differentiation. Our results suggest that TFF1 and TFF3, but not TFF2, may have a role in breast tumor pathogenesis and could be used in the assessment of tumor differentiation and malignancy.
Multiparametric magnetic resonance is assuming an increasingly important role in the diagnosis, initial assessment and monitoring of patients with prostate cancer. This paper offers a more complex ...insight into the application of magnetic resonance imaging with prostate cancer, with a current literature overview. The focus is on the problem of initial prostate cancer evaluation which strongly affects further decision-making and therapeutic interventions. Clinical suggestions based on the current guidelines are also offered.
The aim of this prospective clinical study was to determine the detection rate of prostate cancers by multiparametric magnetic resonance and transrectal ultrasound (mpMRI-TRUS) cognitive fusion ...biopsies in patients with a previously negative TRUS-guided biopsy. Between 1 October 2016 and 1 July 2017, in 101 consecutive patients with elevated antigen (PSA) and/or positive digital rectal examination and after a negative first TRUS biopsy, a second, repeated prostate biopsy was performed. In 24 patients, cognitive fusion mpMRI-TRUS biopsy of the prostate with 8-10 system cores and 1-3 target biopsies was performed, in line with the European Association of Urology guidelines. In 77 patients, only a classic, repeated TRUS guided biopsy was performed. In patients with mpMRI, the detection rate according to PIRADS-v2 reporting system was: PIRADS 1, n = 0; PIRADS 2, n = 0; PIRADS 3, n = 0; PIRADS 4, n = 6/8 (75%); and PIRADS 5, n = 2/3 (67%). In the group of patients with MR-TRUS cognitive fusion biopsy, the prostate cancer detection rate was 8/24 (33%), while in the control group the detection rate was 12/77 (16%), which was statistically significant (t test, p = 0.037, CI 95% is 0.01 to 0.37). Patients with PIRADS ≤ 3 (54%) could have avoided the biopsy.
PDF
