Sustainable forest management in Serbia: State and potentials

Starting from the internationally adopted definition of sustainable forest management, this paper points to the demands of sustainable forest management that can be satisfied by meeting the definite assumptions. The first part presents the objectives of forest and woodland management planning and utilisation, hunting management, and protection of protected areas, as well as the all-inclusive compatible goals of forest policy in Serbia. The second part presents the analysis of the present state of forests in Serbia, in relation to the Pan-European criteria for the assessment of sustainability, and the potentials of our forests to meet all the demands

Forest types of Мt. Кopaonik as an ecological basis of real management planning - sustainable management of forest ecosystems

У еколошки променљивом шумском пределу, успех у предвиђању одговора шумских екосистема на поремећаје настале природно и индуковане начинима газдовања је неизвестан ако не можемо експлицитно да идентификујемо и објаснимо варијације у еколошким условима, које одређују продуктивност и отпорност екосистема...In an ecologically variable forest landscape, the success of predicting the response of forest ecosystems to disturbances occurring naturally or induced by modes of management is uncertain if we cannot explicitly identify and explain the variations in environmental conditions that determine the productivity and resilience of ecosystems. This can be efficiently achieved by exploring the ecological classification of habitats. Although created with the primary objective to provide a more complete basis for ecological forest management planning, the typological classification that has been in use in this country can by all its characteristics be considered an ecological classification. The aim of this study was to thoroughly and comprehensively observe all the significant features of the previously defined basic classification units - forest types in the complex of mesophilic beech forests and beech-coniferous forests in the Kopaonik National Park that are significant for modern forest management planning. Among these characteristics are ecotope and biocenosis characterized primarily by the structural shape, mixture ratio, relationships among the tree species and the size, structure, value and safety of wood volume production. In addition, a special goal of this research was to define the objectives of forest management in relation to the existing situation of determined forest types and realistically established priority functions, as well as an orientational functional optimum of these forests. In 27 sample plots of the average size of 0.33 ha, the survey included the following forest coenoecological groups of forest types: forests of spruce, fir and beech (Abieti - Piceenion-Bl. No. 39) on humus-silicate soils, rendzinas, humus, eutric and dystric brown soils, brown and illimerised soils on limestone, the contact of limestone and silicate rocks and brown podzolic soil..

Landscape Planning and Green Infrastructure in Serbia: From National to Belgrade City Planning

The development of landscape planning in Serbia began in the middle of the last century. The principles and objectives of landscape planning were modeled on European trends and developed within the academic framework of the School of landscape architecture at the Faculty of Forestry of the University of Belgrade. The General Plan of Landscapes (1995) was a failed attempt to introduce landscape planning from the framework of academic and scientific debate to institutional spatial planning in Serbia (Vasiljević, 2008). After the ratification of the European Landscape Convention in 2011, a more favorable climate for landscape planning was created in Serbia. As a result of defining a landscape policy, which harmonized the contemporary conceptualization of landscape planning with planning trends in Serbia, ensued the chapter Protection and Arrangement of Landscapes, as part of the Spatial Plan of the Republic of Serbia 2020. For the first time, the spatial concept included all landscapes – urban and rural/ natural, whereas planning principles integrated the principles of landscape ecology (e.g. landscape connectivity) with the principles of aesthetics of landscapes as systems. Landscape character was defined as the target quality and spatial development was supposed to be aligned with it (Vasiljević, 2013). The landscape-ecological approach in the planning of cityscapes, advocated by many authors had little influence on the planning of Belgrade in the past. As the final stage of the project „Green regulations of Belgrade“, the Program for elaboration of the urban plan of the green spaces system of Belgrade is the first bigger shift towards landscape-ecological planning of the City (Cvejić and Teofilović, 2010). The Plan of General Regulation of Green Spaces of the City of Belgrade (2014) was developed as a result of the project in which green infrastructure and its elements were observed through the core, inner and outer ring of the green spaces system. However, this plan has not been adopted yet, and the reason is the insufficiently grounded form of this planning document for which there are no known and well-established planning mechanisms of implementation. In contemporary academic research in Serbia, the concept of green infrastructure is observed through Turner\u27s interpretation of the urban route that is useful from the aspect of environmental quality in a city (Turner, 1995), Ahern’s strategy of landscape planning in which landscapes are designed as green infrastructure (Ahern, 1995), and the spatial planning strategy, which is considered the only way to a certain future of urban landscapes in the light of climate change (Fabos, 2001). The contemporary theoretical approach to planning at the landscape scale was created in such an atmosphere, based on the concept of landscapes as wholes, transdisciplinary approach to research and landscape character as a new value in spatial development planning (Vasiljević, 2012). This theoretical concept is based on unifying the principles of the multifunctionality of landscapes, redundancy and modularity of landscape functions, diversity of landscape structures and connectedness of landscapes at different levels and adaptability of landscapes (Ahern, 2011). Given that the theoretical framework of landscape planning in Serbia is new, as well as its application within the framework of the 2020 SPRS, and that in terms of planning practice in Serbia the understanding of this theoretical concept is in the domain of socialization and cultural reproduction (Vasiljević, 2012 according to Faludi, 2004), it was necessary to find a principle – the idea that local interpretation of theories and their application can be assumed to be consistent with ideas operating at a higher (often national) scale (Allmendinger, 2002). The principle of connectivity, which is materialized through green infrastructure, was considered as a way to implement this theoretical concept at the local level. In order to achieve landscape stability, the principle of connectivity is applied to establish short-term goals, which are seen as long-term adaptation measures to climate change. However, the experience in the implementation of this principle through legal framework points to numerous problems. Although the criteria for establishing green infrastructure are defined through theoretical and strategic research, the existing landscape policies are limited (European Communities, 2008)

Nanostructured materials for sensing Pb(II) and Cd(II) ions: Manganese oxohydroxide versus carbonized polyanilines?

Nanostructured materials including three different carbonized polyanilines and manganese oxyhydroxide were prepared and evaluated as electrode materials for sensing of lead and cadmium ions in aqueous media. Anodic stripping voltammetry results indicated that all prepared materials could be successfully used for determination of these two heavy metal ions. Carbonized polyaniline-based electrodes have higher signal and lower limits of detection (10-7 М) compared to manganese oxyhydroxide-based electrode. Among the three studied carbonized polyanilines, the one that was derived from polyaniline precursor produced in the presence of 3,5-dinitrosalicyclic acid showed the highest electrocatalytic activity towards the lead and cadmium oxidation. [Projekat Ministarstva nauke Republike Srbije, br. OI172043 i br. III45014

Electrochemical Sensing of Cadmium and Lead Ions in Water by MOF-5/PANI Composites

For the first time, composites of metal-organic framework MOF-5 and conjugated polymer polyaniline (PANI), (MOF-5/PANI), prepared using PANI in its conducting (emeraldine salt, ES) or nonconducting form (emeraldine base, EB) at various MOF-5 and PANI mass ratios, were evaluated as electrode materials for the electrochemical detection of cadmium (Cd2+) and lead (Pb2+) ions in aqueous solutions. Testing of individual components of composites, PANI-ES, PANI-EB, and MOF-5, was also performed for comparison. Materials are characterized by Raman spectroscopy, scanning electron microscopy (SEM) and dynamic light scattering (DLS), and their electrochemical behavior was discussed in terms of their zeta potential, structural, morphology, and textural properties. All examined composites showed high electrocatalytic activity for the oxidation of Cd and Pb to Cd2+ and Pb2+, respectively. The MOF/EB-1 composite (71.0 wt.% MOF-5) gave the highest oxidation currents during both individual and simultaneous detection of two heavy metal ions. Current densities recorded with MOF/EB-1 were also higher than those of its individual components, reflecting the synergistic effect where MOF-5 offers high surface area for two heavy metals adsorption and PANI offers a network for electron transfer during metals’ subsequent oxidation. Limits of detection using MOF/EB-1 electrode for Cd2+ and Pb2+ sensing were found to be as low as 0.077 ppm and 0.033 ppm, respectively. Moreover, the well-defined and intense peaks of Cd oxidation to Cd2+ and somewhat lower peaks of Pb oxidation to Pb2+ were observed at voltammograms obtained for the Danube River as a real sample with no pretreatment, which implies that herein tested MOF-5/PANI electrodes could be used as electrochemical sensors for the detection of heavy metal ions in the real water samples

Effect of carbon support on the activity of monodisperse Co45Pt55 nanoparticles for oxygen evolution in alkaline media

Oxygen evolution reaction (OER) represents the efficiency-limiting reaction in water electrolyzers, metal-air batteries, and unitized regenerative fuel cells. To achieve high-efficiency OER in alkaline media, we fabricated three novel electrocatalysts by the assembly of as-prepared Co45Pt55 alloy nanoparticles (NPs) on three different carbon-based support materials: reduced graphene oxide (CoPt/rGO), mesoporous graphitic carbon nitride (CoPt/mpg-CN), and commercial Ketjenblack carbon (CoPt/KB). Voltammetry studies revealed that CoPt/rGO electrocatalyst provided lower OER overpotentials accompanied by higher currents and specific current density values than the other two studied materials. Moreover, CoPt/rGO outperformed commercial CoPt/C electrocatalysts in terms of notably higher specific current densities. Additionally, it was found that CoPt/rGO electrocatalyst activity increases with increasing temperature up to 85°C, as suggested by the increase in the exchange current density. Electrochemical impedance spectroscopy studies of three electrocatalysts in OER revealed similar charge transfer resistance, although CoPt/rGO provided a higher current density. The main issue observed during long-term chronoamperometry and chronopotentiometry studies is the materials’ instability under OER polarization conditions, which is still to be tackled in future work

NiA and NiX zeolites as bifunctional electrocatalysts for water splitting in alkaline media

NiA and NiX zeolites were prepared and characterised using XRD, FTIR and SEM, and subsequently tested as electrodes for hydrogen (HER) and oxygen (OER) evolution reactions in alkaline media. Linear sweep voltammetry and chronoamperometry techniques showed that NiA has higher catalytic activity for these two reactions, as evidenced by higher current densities, which can be correlated with a higher weight fraction of Ni in this electrocatalyst than in the NiX and with its higher conductivity. HER and OER kinetic parameters, including Tafel slope, exchange current density and apparent activation energy were evaluated. Electrochemical impedance spectroscopy analysis yielded values of the resistance of the solution, charge transfer and mass transfer, as well as double layer capacitance and pseudo-capacitance of the working electrode, at different potentials and temperatures. Unlike the HER, during which the mass transfer resistance of the adsorbed intermediate is dominant in the case of NiA, the OER impedance response is controlled by the charge transfer process itself at the potentials of interest for these process. The overall resistance related to the HER is lower for NiA than for NiX. © 2018 Hydrogen Energy Publications LL

Fe, Cu-decorated carbon material produced from ionic liquids as resourceful electrocatalyst for water splitting

The quest for highly efficient, stable, and economically viable bifunctional electrocatalysts is of paramount relevance for advancing in water splitting for the hydrogen energy sector, particularly in facilitating hydrogen (HER) and oxygen evolution evolution (OER) as cathodic and anodic reaction, respectively. In this study, two ionic liquids containing transition metal Fe or Cu, as well as a mixture of these ionic liquids, were used as precursors to synthesize Fe-, Cu-, and Fe,Cu-decorated carbon materials through simple, straightforward, and inexpensive carbonization processes. Comprehensive characterization via SEM-EDS, TEM, XRD, and XPS established the formation of Fe3O4 and Cu2O species. These materials were systematically evaluated for OER and HER in alkaline electrolyte. Fe,Cu-decorated carbon electrocatalyst exhibited favorable performance for OER, including a low onset potential, and reaching 10 and 50 mA cm−2 at overpotential values of 325 mV and 364 mV, respectively. Notably, grafting both Fe and Cu in the material further augmented its electrocatalytic properties, underscoring the enhanced potential of transition metal-decorated carbon materials for OER applications

Electrochemical Performance of Niobium MXenes with Lanthanum

MXenes are the newest class of two-dimensional nanomaterials characterized by large surface area, high conductivity, and hydrophilicity. To further improve their performance for use in energy storage devices, heteroatoms or functional groups can be inserted into the Mxenes’ structure increasing their stability. This work proposes insertion of lanthanum atoms into niobium-MXene (Nb-MX/La) that was characterized in terms of morphogy, structure, and electrochemical behavior. The addition of La to the Nb-MXene structure was essential to increase the spacing between the layers, improving the interaction with the electrolyte and enabling charge/discharge cycling in a higher potential window and at higher current densities. Nb-MX/La achieved a specific capacitance of up to 157 mF cm-2, a specific capacity of 42 mAh cm-2 at 250 mV s-1, a specific power of 37.5 mW cm-2, and a specific energy of 14.1 mWh cm-2 after 1000 charge/discharge cycles at 50 mA cm-

The current state of transition metal-based electrocatalysts (oxides, alloys, POMs, and MOFs) for oxygen reduction, oxygen evolution, and hydrogen evolution reactions

Climate change is showing its impacts now more than ever. The intense use of fossil fuels and the resulting CO2 emissions are mainly to blame, accentuating the need to develop further the available energy conversion and storage technologies, which are regarded as effective solutions to maximize the use of intermittent renewable energy sources and reduce global CO2 emissions. This work comprehensively overviews the most recent progress and trends in the use of transition metal-based electrocatalysts for three crucial reactions in electrochemical energy conversion and storage, namely, the oxygen evolution (OER), oxygen reduction (ORR), and hydrogen evolution (HER) reactions. By analyzing the state-of-the-art polyoxometalates (POMs) and metal-organic frameworks (MOFs), the performance of these two promising types of materials for OER, ORR, and HER is compared to that of more traditional transition metal oxides and alloy-based electrocatalysts. Both catalytic activity and stability are highly influenced by the adsorption energies of the intermediate species formed in each reaction, which are very sensitive to changes in the microstructure and chemical microenvironment. POMs and MOFs allow these aspects to be easily modified to fine-tune the catalytic performances. Therefore, their chemical tunability and versatility make it possible to tailor such properties to obtain higher electrocatalytic activities, or even to obtain derived materials with more compelling properties towards these reactions