Pyrolysis is an optimal thermochemical process for obtaining valuable products (char, oil, and gas) from waste tires. The preliminary research was done on the three groups of samples acquired by cutting the same waste tire of a passenger vehicle into cylindrical granules with a base diameter of 3, 7, and 11 mm. Each batch weighed 10 g. The heating rate was 14 °C/min, and the final pyrolysis temperature was 750 °C, with 90 s residence time. After the pyrolysis product yields were determined for all of the three sample groups, further research was performed only on 3 mm granules, with the same heating rate, but with altered final pyrolytic temperatures (400, 450, 500, 550, 600, 650, 700, and 750 °C). The results of this study show that thermochemical decomposition of the waste tire sample takes place in the temperature range of 200–500 °C, with three distinct phases of degradation. The highest yield of the pyrolytic oil was achieved at a temperature of 500 °C, but further heating of volatile matters reduced the oil yield, and simultaneously increased the yield of gas, due to the existence of secondary cracking reactions. The analysis of pyrolytic oil and char showed that these products can be used as fuel.
This work presents the results of the first Serbian monitoring campaign performed to assess the occupational exposure of petrochemical industry workers to benzene (B), toluene (T), ethylbenzene (E), and xylene (X), known collectively as BTEX. The following urinary biomarkers were investigated: phenol, hippuric acid, o-Cresol, p-Cresol, and creatinine. BTEX compounds were collected in 2014 using Casella passive samplers. Multivariate statistical analysis was performed to put in evidence the correlation between the BTEX measured in air and the concentration of urinary biomarkers. While the results indicate an elevated presence of benzene in the air in the working environment studied that surpasses the national and European Occupational Exposure Limits (OEL), the levels of the remaining (TEX) parameters measured were below the OEL. The high relative standard deviations (RSD) for the concentrations of each BTEX compound (68–161 mg m−3) point toward an intensive occupational exposure to BTEX. This was confirmed by relevant urine biomarkers, particularly by the mean values of phenol, which were ten and fourteen times higher than the ones found in the control group (14–12 mg g−1 of creatinine). On average, workers are at a higher risk of developing cancer (6.1 × 10−3), with risk levels exceeding the US EPA limits. Benzene levels should therefore be maintained under tight controls and monitored via proper urinary biomarkers.
11 July 2016 in Waste Management & Research: The Journal for a Sustainable Circular Economy
This paper outlines the approach that can assist decision makers to have first preliminary insights regarding costs of complying with requested European Union municipal waste management goals in transition and developing countries. Serbia, as a joining member of European Union, must confront itself with the challenges resulting from European Union waste management directives. Implementation of waste separation units and the construction of sanitary landfills is already in place in Serbia. However, new waste management practice will need additional transformation and will require implementation of waste treatment technologies for additional management of generated waste. Implementation of analyzed best available technology/techniques for waste treatment can support the country’s effort in reaching the policy goals. However, the question here is how much will the implementation of additional waste treatments influence the overall waste management costs? Results of the scenario’s financial viability show that composting and sanitary landfill are the most viable solutions regarding the costs, even under increasing discount rates. Although different discount rates influence the overall gate fees and net present values, the level of affordability for different scenarios remains the same.
Aims: This study aimed to assess nursing workload in Cardiac Intensive Care Unit (CICU) after three cardiothoracic surgery procedures during first four postoperative days using Nursing Activities Score (NAS) and Nine Equivalents of Nursing Manpower Use Score (NEMS) systems, to compare their performance for that purpose and to investigate association between nursing workload and type of surgery.Design: A comparative study.Methods: The research environment includes CICU of the University Hospital for Cardiovascular Diseases in Serbia. A total of 808 patients who underwent coronary, valvular, or combined surgery, resulting in 2282 filled NAS and NEMS pairs chart. Statistical analysis was performed using SPSS‐19. The correlation between NAS and NEMS was tested by Spearman's correlation coefficient. Differences were considered statistically significant at p < 0.05.Results: The lowest median of cumulative NAS 176 (175‐257) and NEMS 76 (64‐91) had coronary surgery patients, the highest NAS 224.5 (178‐334.5) and NEMS 83 (69‐121) had those with combined surgery; this difference was statistically significant (p < 0.001). The median of both scores decreased after surgery, with the following values from the first to the fourth postoperative day: NAS from 104 (102‐105) to 81 (74‐85) and NEMS from 46 (42–46) to 30 (30–37). The difference in mean values of both scores between the first and the fourth postoperative day was statistically significant (p < 0.001). NAS and NEMS were in a positive, strong correlation (r = 0.913; p < 0.005).Conclusion: Both scores can be used to measure nursing workload, identify the required number of nurses in CICU, and support task allocation. NAS may have an advantage because it better describes extensive postoperative monitoring and care needed for cardiac surgery patients. Nursing workload is associated with type of surgery, with the highest workload measured in patients who underwent combined surgery procedure and on the first postoperative day.
1 June 2024 in International Journal of Technology and Design Education
Considering that the determination of fire hazard zones in warehouses is not sufficiently researched and studied, this paper aims to present a new methodological approach concerning the mentioned issue. Based on the COPRAS multi-criteria decision-making method, a new method was developed for the precise determination of potential zones where there is a risk of fire. The advantage of the described method is that it allows the quick and easy determination of all-orientation fire risk zones. The method requires fewer hardware resources compared to the existing ones and enables the display of the warehouse space in the form of a 3D model with calculated fire hazard zones. The mentioned procedure represents the first step when planning the layout and arrangement in the warehouse itself. The effectiveness of the proposed method was confirmed through a suitable numerical example.