U ovom radu autorica daje osvrt na prednosti i nedostatke ulaganja u nekretnine te provodi analizu proteklih ciklusa na Hrvatskom tržištu nekretnina. Kao neke od glavnih prednosti ističu se ...atraktivan prinos (yield), niska volatilnost i zaštita od inflacije. S druge strane, glavni nedostaci su slaba likvidnost, transakcijski troškovi te u najvećem broju slučajeva aktivno bavljenje investicijom (nije pasivni prihod). Iz analize protekla 2 ciklusa (pada i rasta) potvrđuje se da cijene nekretnina koreliraju s ekonomskom situacijom te da imaju nisku volatilnost, odnosno značajnije promjene cijena se događaju u višegodišnjim periodima.
The Framework Agreement on the Sava River Basin—FASRB (2002) is the first regional (river basin) agreement, except the Dayton Peace Agreement (1995), concluded by the countries originated by the ...decomposed Socialist Federal Republic of Yugoslavia (SFRY). The conclusion of the FASRB was strongly supported by the international comunity, acting intensively in the Balkan region after the wars in the nineties. This Agreement is an example of positive development in managing of natural (i.e. water) resources in a post-war period.
The different phases and aspects of drafting, negotiation, signature, ratification and implementation of the Framework Agreement on the River Sava Basin are presented here. The paper contains brief data on the geographical, historical and political features of the Sava River Basin, on the former Yugoslavia disintegration, on the Stability Pact for South Eastern Europe’s role in the proces of drafting the Agreement as well as on the Sava Initiative description. The paper also contains details on the goals, general principles, areas of cooperation, mechanism of cooperation, monitoring implementation dispute settlement, protocols, the Statute of the International Sava River Basin Commission and the dispute settlement provisions.
A separate part of the paper comprises some details on the current status of cooperation in certain fields covered by the Agreement, including the status of (inland) navigation, with brief references on the FASRB implemenation in the Republic of Croatia. The efforts on the unification of the basic navigation rules, establishment, maintenance and improvement of the uniform waterway marking system as well as on the rehabilitation and development of the Sava River Waterway and development of the River Information Services are presented. The activities concerning water management issues such as the development of the Sava River Basin Management Plan, the establishment of a system of measures, activities, warnings and alarms in case of extraordinary impacts of the water regime caused by pollution or floods, ice occurrence, droughts and water shortages, the establishment of an integrated information system, as well as provisions regulating dispute settlement are highlighted. Activities on drafting new treaties, in terms of Protocols to the FASRB, are also reviewed.
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FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract Comprehensive grasp of heat and mass transfer, particularly in applications involving liquid-vapor phase change, hinges on management of nucleation, growth, and detachment of vapor bubbles. ...Various parameters influence the dynamics of phase-change heat and mass transfer and thus dictate the interactions between the surface, the liquid, and the vapor, profoundly impacting the underlying processes. To tailor these phenomena and harness them for technical applications involving high heat flux densities and intense mass transfer, such as boiling and electrolysis, surface functionalization is under intense development. By designing structured surfaces and creating preferential nucleation sites that promote heterogeneous nucleation, it is possible to exert control over the location and density of active nucleation sites on the surface. This, in turn, enables the regulation of bubble growth and detachment from the surface. With the aim of identifying optimal surface treatments for functionalizing surfaces and enhancing their performance in phase-change applications, we evaluated the nucleation, growth and detachment of a single bubble in a liquid-vapor phase change on untextured and laser-textured surfaces during water electrolysis. Platinum was chosen as the preferential material due to its favourable electrochemical properties for the hydrogen evolution reaction in acidic media. Electrolysis was performed at various voltages and the bubble dynamics were evaluated through high-speed imaging to investigate the intricacies of bubble growth and their mutual interactions. At 3.5 V using the laser textured surface, hydrogen bubbles detaching from the electrode surface had on average 40% smaller diameter, while the frequency of their detachment was 2,5-times higher compared to the untextured surface. This opens the possibility for further research that could lead to improving the efficiency of electrolysis.
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•Surface superheat increases during long-term operation in water and salt solutions.•Nucleation activity drops due to wetting, surface chemistry and topography changes.•Boiling curve ...stability is an uncertain indication of surface’s long-term operation.•Aging mechanisms found in water appear in solutions with lower relative importance.•Laser-texturing improves resistance to boiling-induced degradation by up to tenfold.
Long-term boiling stability marks an important and often overlooked characteristic when engineering advanced interfaces for efficient phase-change heat removal. This study presents long-term pool boiling on functionalized smooth and laser-textured copper interfaces in de-ionized water and in an aqueous solution of calcium sulphate. Each surface was exposed to nucleate boiling for several hundred hours and wettability, morphology and surface chemistry were evaluated prior to and after each test. In addition, consecutive pool boiling curves were recorded on all samples. Our findings indicate an increase of wall superheat on all samples, caused by added thermal resistance in the salt solution and by diminished nucleation activity in water. The latter resulted from spatially non-uniform and interconnected mechanisms of wettability transition towards hydrophilicity, surface chemistry changes and topography deformation. These mechanisms also appeared in salt solutions, where their relative importance compared to dominant influence of scaling was linked to crystallization-mitigative ability of the interface. In both liquids, laser-textured surfaces exhibited up to an order of magnitude lower degradation rates. Our results also emphasize the importance of evaluation times of several days to accurately gauge boiling-induced changes to the surface and the ambiguity of evaluating the latter through boiling curve stability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract After sustaining long-term nucleate boiling, any surface is prone to changes over time, which signifies an important operational characteristic for reliable thermal management; however, ...recent research of this topic is extremely scarce. In this work, we first present long-term pool boiling experiments on samples of different surface topography and morphology in de-ionized water and in an aqueous salt solution. We show the changes induced by vigorous bubble nucleation over the course of several hundred hours of operation, discussing the underlying degradation phenomena. Following this, we present an adaptive data-driven prognostic approach, capable of estimating the remaining useful life (RUL) of a boiling surface in real time, based on change of surface temperature. The method consists of (i) a Kalman filter to identify the degradation drift model and (ii) a Monte Carlo simulation to propagate the drift to the terminal threshold, obtaining a distribution of predicted RUL values. Its practical applicability, validated on experimental results, is reinforced by its advantageous features of (i) prognostic performance not depending on the boiling surface or its degradation mechanisms, (ii) low computational demand and (iii) numerous options for individual tuning and extensions.
The enhancement of boiling heat transfer has been extensively shown to be achievable through surface texturing or fluid property modification, yet few studies have investigated the possibility of ...coupling both enhancement approaches. The present work focuses on exploring the possibility of concomitant enhancement of pool boiling heat transfer by using TiO2-water nanofluid in combination with laser-textured copper surfaces. Two mass concentrations of 0.001 wt.% and 0.1 wt.% are used, along with two nanoparticle sizes of 4–8 nm and 490 nm. Nanofluids are prepared using sonification and degassed distilled water, while the boiling experiments are performed at atmospheric pressure. The results demonstrate that the heat transfer coefficient (HTC) using nanofluids is deteriorated compared to using pure water on the reference and laser-textured surface. However, the critical heat flux (CHF) is significantly improved at 0.1 wt.% nanoparticle concentration. The buildup of a highly wettable TiO2 layer on the surface is identified as the main reason for the observed performance. Multiple subsequent boiling experiments using nanofluids on the same surface exhibited a notable shift in boiling curves and their instability at higher concentrations, which is attributable to growth of the nanoparticle layer on the surface. Overall, the combination of nanofluids boiling on a laser-textured surface proved to enhance the CHF after prolonged exposure to highly concentrated nanofluid, while the HTC was universally and significantly decreased in all cases.
Prior studies have evidenced the potential for enhancing boiling heat transfer through modifications of surface or fluid properties. The deployment of nanofluids in pool boiling systems is ...challenging due to the deposition of nanoparticles on structured surfaces, which may result in performance deterioration. This study addresses the use of TiO
-water nanofluids (mass concentrations of 0.001 wt.% and 0.1 wt.%) in pool boiling heat transfer and concurrent mitigation of nanoparticle deposition on superhydrophobic laser-textured copper surfaces. Samples, modified through nanosecond laser texturing, were subjected to boiling in an as-prepared superhydrophilic (SHPI) state and in a superhydrophobic state (SHPO) following hydrophobization with a self-assembled monolayer of fluorinated silane. The boiling performance assessment involved five consecutive boiling curve runs under saturated conditions at atmospheric pressure. Results on superhydrophilic surfaces reveal that the use of nanofluids always led to a deterioration of the heat transfer coefficient (up to 90%) compared to pure water due to high nanoparticle deposition. The latter was largely mitigated on superhydrophobic surfaces, yet their performance was still inferior to that of the same surface in water. On the other hand, CHF values of 1209 kW m
and 1462 kW m
were recorded at 0.1 wt.% concentration on both superhydrophobic and superhydrophilic surfaces, respectively, representing a slight enhancement of 16% and 27% compared to the results obtained on their counterparts investigated in water.
Acute kidney injury (AKI) is a frequent complication in ST-elevation myocardial infarction (STEMI) patients. Factors other than contrast exposure have been suggested as major contributors to renal ...dysfunction in patients undergoing primary percutaneous coronary intervention (PPCI). Our aim was to assess the incidence and risk factors of AKI in high-risk STEMI patients, mostly treated by PPCI with implemented measures to prevent contrast-induced AKI. We retrospectively analyzed data of 245 STEMI patients (165 men, mean age 63.9 ± 11.9 years) admitted to the Department of Medical Intensive Care Unit. Demographic, clinical, and mortality data were compared between AKI and non-AKI group. AKI was defined as a 1.5-fold increase in serum creatinine from baseline level within 24-48 hours. AKI developed in 34/245 (13.9%) patients. PPCI was performed in 226/245 (92.2%) of all STEMI cases, with no difference between AKI and non-AKI group. There were significant differences between AKI and non-AKI group in diabetes mellitus (41.2% vs. 20.9%), prior MI (26.5% vs. 11.8%), prior resuscitation (38.2% vs. 12.4%), admission acute heart failure AHF (44.1% vs. 12.8%), in-hospital AHF (70.6% vs. 17.5%), and hospital-acquired infection HAI (79.4% vs. 18.0%). Significantly more AKI patients had increased admission CRP ≥25 mg/L (38.2% vs. 11.8%), peak CRP ≥50 mg/L (91.2% vs. 36%), admission troponin I ≥10 mg/L (44.1% vs. 24.6%), peak troponin I ≥50 mg/L (64.7% vs. 44.1%), peak NT-proBNP ≥400 pmol/L (82.4% vs. 27.5%), and ejection fraction <45% (76.5% vs. 33.6%). Mortality was significantly increased in AKI group, including in-hospital (52.9% vs. 7.1%), 30-day (64.7% vs. 10.7%) and 6-month mortality (70.6% vs. 13.7%). Significant independent predictors of AKI were prior resuscitation (OR 4.171, 95% CI 1.088-15.998), HAI (OR 7.974, 95% CI 1.992-31.912), and peak NT-proBNP (OR 21.261, 95% CI 2.357-191.795). To reduce the risk of AKI in STEMI patients, early diagnosis and treatment of AHF and HAIs are advisable.
Acute kidney injury (AKI) is a frequent complication in ST-elevation myocardial infarction (STEMI) patients. Factors other than contrast exposure have been suggested as major contributors to renal ...dysfunction in patients undergoing primary percutaneous coronary intervention (PPCI). Our aim was to assess the incidence and risk factors of AKI in high-risk STEMI patients, mostly treated by PPCI with implemented measures to prevent contrast-induced AKI. We retrospectively analyzed data of 245 STEMI patients (165 men, mean age 63.9 + or - 11.9 years) admitted to the Department of Medical Intensive Care Unit. Demographic, clinical, and mortality data were compared between AKI and nonAKI group. AKI was defined as a 1.5-fold increase in serum creatinine from baseline level within 24-48 hours. AKI developed in 34/245 (13.9%) patients. PPCI was performed in 226/245 (92.2%) of all STEMI cases, with no difference between AKI and non-AKI group. There were significant differences between AKI and non-AKI group in diabetes mellitus (41.2% vs. 20.9%), prior MI (26.5% vs. 11.8%), prior resuscitation (38.2% vs. 12.4%), admission acute heart failure AHF (44.1% vs. 12.8%), in-hospital AHF (70.6% vs. 17.5%), and hospital-acquired infection HAI (79.4% vs. 18.0%). Significantly more AKI patients had increased admission CRP greater than or equal to25 mg/L (38.2% vs. 11.8%), peak CRP greater than or equal to50 mg/L (91.2% vs. 36%), admission troponin I greater than or equal to10 microg/L (44.1% vs. 24.6%), peak troponin I greater than or equal to50 microg/L (64.7% vs. 44.1%), peak NT-proBNP greater than or equal to400 pmol/L (82.4% vs. 27.5%), and ejection fraction <45% (76.5% vs. 33.6%). Mortality was significantly increased in AKI group, including in-hospital (52.9% vs. 7.1%), 30-day (64.7% vs. 10.7%) and 6-month mortality (70.6% vs. 13.7%). Significant independent predictors of AKI were prior resuscitation (OR 4.171, 95% CI 1.088-15.998), HAI (OR 7.974, 95% CI 1.992-31.912), and peak NT-proBNP (OR 21.261, 95% CI 2.357-191.795). To reduce the risk of AKI in STEMI patients, early diagnosis and treatment of AHF and HAIs are advisable. KEY WORDS: ST-elevation myocardial infarction; STEMI; acute kidney injury; AKI; predictors; mortality; acute heart failure; infection
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