GIS-Based Forest Fire Susceptibility Zonation with IoT Sensor Network Support, Case Study-Nature Park Golija, Serbia.

The territory of the Republic of Serbia is vulnerable to various natural disasters, among which forest fires stand out. In relation with climate changes, the number of forest fires in Serbia has been increasing from year to year. Protected natural areas are especially endangered by wildfires. For Nature Park Golija, as the second largest in Serbia, with an area of 75,183 ha, and with MaB Reserve Golija-Studenica on part of its territory (53,804 ha), more attention should be paid in terms of forest fire mitigation. GIS and multi-criteria decision analysis are indispensable when it comes to spatial analysis for the purpose of natural disaster risk management. Index-based and fuzzy AHP methods were used, together with TOPSIS method for forest fire susceptibility zonation. Very high and high forest fire susceptibility zone were recorded on 26.85% (Forest Fire Susceptibility Index) and 25.75% (fuzzy AHP). The additional support for forest fire prevention is realized through an additional Internet of Thing (IoT)-based sensor network that enables the continuous collection of local meteorological and environmental data, which enables low-cost and reliable real-time fire risk assessment and detection and the improved long-term and short-term forest fire susceptibility assessment. Obtained results can be applied for adequate forest fire risk management, improvement of the monitoring, and early warning systems in the Republic of Serbia, but are also important for relevant authorities at national, regional, and local level, which will be able to coordinate and intervene in a case of emergency events.

Calculation of reaction forces in the boiler supports using the method of equivalent stiffness of membrane wall.

The values of reaction forces in the boiler supports are the basis for the dimensioning of bearing steel structure of steam boiler. In this paper, the application of the method of equivalent stiffness of membrane wall is proposed for the calculation of reaction forces. The method of equalizing displacement, as the method of homogenization of membrane wall stiffness, was applied. On the example of "Milano" boiler, using the finite element method, the calculation of reactions in the supports for the real geometry discretized by the shell finite element was made. The second calculation was performed with the assumption of ideal stiffness of membrane walls and the third using the method of equivalent stiffness of membrane wall. In the third case, the membrane walls are approximated by the equivalent orthotropic plate. The approximation of membrane wall stiffness is achieved using the elasticity matrix of equivalent orthotropic plate at the level of finite element. The obtained results were compared, and the advantages of using the method of equivalent stiffness of membrane wall for the calculation of reactions in the boiler supports were emphasized.

Hip and Knee Osteoarthritis in Patients with Chronic Myeloproliferative Neoplasms: A Cross-Sectional Study.

BACKGROUND: Osteoarthritis (OA) is a progressive degenerative disease with an inflammatory background. Chronic myeloproliferative neoplasms (MPN) are clonal hematopoietic disorders characterized by chronic inflammation and a tendency for connective tissue remodeling. AIM: This study aimed to investigate the prevalence and associated risk factors of symptomatic OA (sOA) in MPN patients. PATIENTS AND METHODS: A total of 100 consecutive MPN (39 essential-thrombocythemia, 34 polycythemia-vera, 27 myelofibrosis) patients treated in two community hematologic centers were cross-sectionally evaluated. Patients were required to have both symptoms attributable to hip and/or knee OA and radiographic confirmation to be considered as having sOA. RESULTS: The prevalence of hip and/or knee sOA was significantly higher among MPN patients than the previously reported prevalence in the general population of similar age (61% vs. 22%, p < 0.001). Hip sOA was present in 50%, knee sOA in 51% and sOA of both localizations in 41% of patients. A high proportion of MPN patients had radiographic signs of hip OA (94%) and knee OA (98%) in the presence of attributable symptoms. Among the other factors, sOA was univariately associated with the presence of JAK2 mutation, myelofibrosis phenotype, older age, higher body weight, and higher MPN-SAF score (p < 0.050 for all analyses). In the multivariate analysis, older age (odds ratio = 1.19, 95% confidence interval-CI 1.06-1.33) and higher body weight (OR = 1.15, 95% CI 1.06-1.25) were recognized as independent risk factors for sOA. On the other hand, cytoreductive treatment was a protective factor for sOA (OR = 0.07, 95% CI 0.006-0.86). CONCLUSIONS: The prevalence of sOA in MPN patients was higher than that in the general population and seems to correlate with older age, increased myeloproliferation and a higher inflammatory state. Whether cytoreductive treatment may postpone OA development in MPN patients warrants additional confirmation.

Influence of Anticorrosive Pigment, Dry-Film Thickness and Conditioning Time on Protective Properties of Two-Component Epoxy Primer.

The main protective properties of two-component epoxy coating are connected by the formation of a barrier of a certain thickness between the material and aggressive, environmentally induced reactants. Anticorrosive pigment is added to the coating in order to improve its protective effects. The conditioning time refers to the time interval required for the achievement of satisfactory cohesion bonds between the coating components, as well as a satisfactory adhesion force between the coating and the base material surface. This paper presents insights obtained after experimental research into the influence of input variables (the content of anticorrosive pigment in the coating, dry-film thickness, and conditioning time) on corrosion resistance. The specimens were kept in the aggressive atmosphere of a salt-spray test chamber within time intervals of 120, 240 and 480 h, where they were cyclically sprayed with a 5% sodium chloride (NaCl) solution, and then examined in laboratory conditions. Such a procedure imitated the aggressive conditions of a service environment. After exposure in the salt-spray test chamber, the specimens were tested to determine the protective properties of the coating and to evaluate damage occurring on the coating, with the purpose of assessing the coating quality in relation to the stated input variables. At all times, when the test samples were exposed to the salt chamber atmosphere, the anti-corrosion pigment content was found to have the greatest influence with the thickness of the dry coating film. The conditioning time was an influential factor to a lesser extent, and only in some observed cases. By analyzing the interactions of the input variables and the results obtained based on mathematical models and reaction surfaces, it was possible to define the most optimal values of the input parameters. For example, after 480 h of exposure in a salt chamber, notch corrosion of 0.6 mm was observed at a dry-film thickness of D1 and an anti-corrosion pigment content of 10%.

Optimization of Synchropulsed MIG Welding Process Parameters for Welding of AW 5083 Sheets.

Metal inert gas (MIG) welding is one of the processes most commonly used for joining metals, especially for joining aluminum and its alloys. The application of a pulsed current in an electric arc allows better controllability of the molten droplets and the arc transition, which subsequently leads to welds with characteristic flaky joints of better quality. In this paper, the optimization of parameters for welding aluminum alloys using the synchropulse welding process is investigated. By observing the input variables that have the greatest influence on the change in appearance of the welding current characteristics (delta wire feed from 0.1 to 6.0 m/min, frequency F from 0.5 to 3 Hz, duty cycle from 10% to 90%), it is possible to perform an optimization to achieve the desired output values. The output variables of the experiments are defined as insufficient/excessive throat thickness (mm), depth of penetration (mm), and weld width (mm); and for the desired quality of the welded joint the most acceptable range of its values is selected, the numerical optimization implementation. The experiment has shown that the delta wire feed has the greatest effect on the observed properties, while the influence of frequency F and duty cycle is somewhat smaller, but the factors responsible for the observed output properties are still significant. From all this, it is possible to select specific values of these input variables to define the best possible observed properties and to determine the characteristics of the defined mathematical models.

Modeling and Optimization of Cut Quality Responses in Plasma Jet Cutting of Aluminium Alloy EN AW-5083.

The plasma jet cutting process has a high potential for the machining of aluminium and its alloys. Aluminium is well known as a highly thermally conductive and sensitive material, and because of that there exist uncertainties in defining process parameters values that lead to the best possible cut quality characteristics. Due to that, comprehensive analysis of process responses as well as defining optimal cutting conditions is necessary. In this study, the effects of three main process parameters-cutting speed, arc current, and cutting height-on the cut quality responses: top kerf width, bevel angle, surface roughness Ra, Rz, and material removal rate were analyzed. Experimentations were conducted on aluminium EN AW-5083. In order to model relations between input parameters and process responses and to conduct their optimization, a novel hybrid approach of response surface methodology (RSM) combined with desirability analysis was presented. Prediction accuracy of developed responses regression models was proved by comparison between experimental and predicted data. Significance of process parameters and their interactions was checked by analysis of variance (ANOVA). Desirability analysis was found as an effective way to conduct multi-response optimization and to define optimal cutting area. Due to its simplicity, the novel presented approach was demonstrated as a useful tool to predict and optimize cut quality responses in plasma jet cutting process of aluminium alloy.

CMT Additive Manufacturing Parameters Defining Aluminium Alloy Object Geometry and Mechanical Properties.

Additive manufacturing technologies based on metal melting use materials mainly in powder or wire form. This study focuses on developing a metal 3D printing process based on cold metal transfer (CMT) welding technology, in order to achieve enhanced productivity. Aluminium alloy test specimens have been fabricated using a special 3D printing technology. The probes were investigated to find correlation between the welding parameters and geometric quality. Geometric measurements and tensile strength experiments were performed to determine the appropriate welding parameters for reliable printing. The tensile strength of the product does not differ significantly from the raw material. Above 60 mm height, the wall thickness is relatively constant due to the thermal balance of the welding environment. The results suggest that there might be a connection between the welding parameters and the printing accuracy. It is demonstrated that the deviation of ideal geometry will be the smallest at the maximum reliable welding torch movement speed, while printing larger specimens. As a conclusion, it can be stated that CMT-based additive manufacturing can be a reliable, cost-effective and rapid 3D printing technology with enhanced productivity, but without significant decrease in mechanical stability.

Total hip arthroplasty in avascular necrosis of the femoral head in a patient with transplanted heart.

With the improvement of transplantation techniques and immunosupresive treatment of transplanted patients, the number of heart transplantations increases worldwide including Croatia. The survival of such patients is significantly increased. Therefore, the prevalence of known complications is high, one of which is avascular necrosis of the femoral head. This paper presents a case of the first patient in Croatia who underwent bilateral hip arthroplasty due to bilateral avascular necrosis of the femoral head as a side effect of corticosteroid therapy after heart transplantation.

Traumatic optic neuropathy - to treat or to observe?

We present a case of acute traumatic optic neuropathy in 54 year old male patient. The patient presented with acute loss of vision in the right eye due to a blunt trauma to the eye. Lid haematoma and subconjunctival hemorrhage were present. Fluorescein staining was negative, anterior chamber and lens was clear. Intraocular pressure was normal. Retina and optic nerve head appeared normal on fundoscopy. The vision was "counting fingers at 1 meter" in the right eye. Color test indicated color perception dysfunction of the right eye. Relative afferent pupillary defect (RAPD) was positive. Ocular ultrasound, orbital X ray and CT scan was normal, but visual evoked potentials test was pathologic. The consideration was made whether to treat a patient or not since there are no consensus on the treatment of traumatic optic neuropathy. We decided to treat the patient immediately with the megadoses of steroids following the protocol suggested by Cerovski. The patient responded well to the treatment and recovered vision to normal.