Konzervacijska poljoprivreda sa svojim temeljnim principima (trajna pokrovnost tla, minimalna obrada i plodored) jedan je od najučinkovitijih sustava za prilagodbu poljoprivredne proizvodnje ...nepovoljnim uvjetima klimatskih promjena. Brojne prednosti konzervacijske poljoprivrede dodatno su izražene integracijom pokrovnih usjeva u plodored. Pokrovni usjevi uvode se u inovativne sustave biljne proizvodnje u svrhu poboljšanja kemijskih, fizikalnih i bioloških svojstava tla uz pozitivan utjecaj na bioraznolikost i doprinos održivosti poljoprivredne proizvodnje. Cilj ovoga rada je pregledno prikazati neke od glavnih uloga pokrovnih usjeva u konzervacijskoj poljoprivredi s osvrtom na zaštitu tla od erozije, konzervaciju vode i hraniva te utjecaj na organsku tvar i strukturu tla.
Conservation agriculture with its basic principles (permanent soil cover, minimal soil disturbance and crop rotation) is one of the most effective tools for adapting agricultural production to the adverse conditions of climate change. The numerous advantages of conservation agriculture are further expressed by the integration of cover crops into the crop rotation. Cover crops are introduced into innovative plant production systems for the purpose of improving the chemical, physical and biological properties of the soil with a positive impact on biodiversity and contributing to the sustainability of agricultural production. The aim of this paper is to present some of the main roles of cover crops in conservation agriculture with emphasis on soil erosion protection, water and nutrient conservation, and the impact on organic matter and soil structure.
Team formation in an environment where some relevant parameters are not known in advance is a challenging problem. Communicating automata and distributed algorithms have been used to describe ...protocols for team formation. A high‐level specification provides a mathematical description of a protocol or a program. TLA +$$ {}^{+} $$ is a formal specification language designed to provide high‐level specifications of concurrent and distributed systems. The associated model checker known as TLC is capable of model checking the TLA +$$ {}^{+} $$ specifications. Recently, formal specification of a team formation protocol is given using TLA +$$ {}^{+} $$ when there is a single initiator (an agent or a robot) that initiates the team formation. Using TLA +$$ {}^{+} $$, we examine the formal specification for the multiple initiator situation and demonstrate that a composition technique can yield a single monolithic specification for the multiple initiator situation from the single initiator situation specification. We have used models of varying sizes, and the TLC model checker has confirmed that the protocol's specifications meet certain desired characteristics in each case.
One of the major tools for power system operators is optimal power flow (OPF) which is an important tool in both planning and operating stages, designed to optimize a certain objective over power ...network variables under certain constraints. Without doubt one of the simple but powerful optimization algorithms in the field of evolutionary optimization is imperialist competitive algorithm (ICA); outperforming many of the already existing stochastic and direct search global optimization techniques. The original ICA method often converges to local optima. In order to avoid this shortcoming, we propose a new method that profits from teaching learning algorithm (TLA) to improve local search near the global best and a series of modifications is purposed to the assimilation policy rule of ICA in order to further enhance algorithm’s rate of convergence for achieving a better solution quality. This paper investigates the possibility of using recently emerged evolutionary-based approach as a solution for the OPF problem which is based on hybrid modified ICA (MICA) and TLA (MICA–TLA) for optimal settings of OPF control variables. The performance of this approach is studied and evaluated on the standard IEEE 30-bus and IEEE 57-bus test systems with different objective functions and is compared to methods reported in the literature. The hybrid MICA–TLA provides better results compared to the original ICA, TLA, MICA, and other methods reported in the literature as demonstrated by simulation results.
•A novel hybrid algorithm.•Hybrid MICA–TLA has been offered as a novel solution for solving OPF problem.•Hybrid MICA–TLA was successfully implemented.
The BPMN standard notation allows business process designers to model both intra-organizational processes and inter-organizational collaborations. A great effort has been devoted in proposing formal ...semantics for BPMN, and, fewer, in providing dedicated verification tools. Still, some advanced features of BPMN, namely communication or time-related constructs, are often set aside. This becomes an issue as BPMN gains interest outside of its original scope, e.g., for the IoT where communication and time play an important role. In this paper, we propose a formal semantics for a subset of BPMN. This semantics takes into account not only the usual gateways, but also sub-processes, inter-process communication, and time-related constructs. In contrast to transformational approaches, which give a semantics to BPMN by mapping it to some formal model (e.g., transition systems or Petri nets), our approach is based on a direct formalization in first-order logic that is then realized in a straightforward way into the TLA+ formal language. We build on the TLA+ model-checker, TLC, to provide process designers with a verification framework, fbpmn, that one may use to check BPMN and workflow specific properties. Our tools and our model database are open source and freely available online.
•A direct formal semantics for a subset of BPMN, including sub-processes, communication and time constructs.•Automated verification of intra-organization workflows and inter-organization collaborations.•Seven models for communication, two models for time.•Communication models and properties of interest are easily extensible.•Open source and freely available tools and model repository.
Gujavice se smatraju jednim od najvažnijih skupina životinja koje žive u tlu. Vrste iz porodice Lumbricidae karakterizira uočljiv zadebljali prsten na kolutićavom tijelu, dok su vrste iz porodice ...Enchytraeidae manje i najčešće prozirne. Gujavice imaju razne važne uloge u ekosustavima. Značajno modificiraju fizička, kemijska i biološka svojstva tla. Svojim načinom hranjenja pospješuju miješanje i inkorporiranje organskih ostataka u tlo te njihovu razgradnju, čime utječu na kruženje hranjivih tvari i njihovu dostupnost drugim organizmima. Ukopavanjem u tlo potiču drenažu, prozračivanje i razvoj strukture tla. Svime time mogu utjecati na stanište i aktivnosti drugih organizama unutar ekosustava tla. Gujavice stoga često nazivaju „inženjerima ekosustava“ jer svojom aktivnošću uvelike pridonose plodnosti tla.
The loss of soil organic carbon stock and increased CO2 emission from soil are induced by various human activities. The aim of this study was to examine whether an anthropogenic influence during the ...regeneration of a pedunculate oak ( Quercus robur L.) stand can affect the increment of CO2 emission from the soil. The research was carried out within three plots, out of which two were exposed to different degrees of anthropogenic influence. The air samples were collected using the soil respiratory chambers and analysed using the gas chromatograph Agilent 8890. Based on the obtained results, soil temperature and moisture as the most dominant drivers of the CO2 emission had different effects on the CO2 flux from soil depending on the intensity of anthropogenic influences and environmental conditions. Within the experimental plot with the significant soil alteration, a reliable positive correlation was detected for the CO2 flux with the soil temperature (r = 0.77, p < 0.05). High significant correlation was observed considering soil moisture (r = 0.85, p < 0.05) in the natural soil where the application of pesticides was conducted. The results showed that both soils that were exposed to the anthropogenic influences had notably higher values of the CO2 flux in comparison to the reference natural soil without anthropogenic impacts.
Rad u šumarstvu razumijeva sve ljudske aktivnosti koje su prijeko potrebne za obavljanje planiranih šumarskih poslova, a radi ostvarivanja dobrobiti od šume i šumskoga zemljišta. U skladu s tim šumarski radnici, tj. ljudi s potrebnim znanjima, vještinama i sposobnostima, uz odgovarajuća sredstva za rad i predmet rada predstavljaju temeljni čimbenik šumarske proizvodnje. Stručno osposobljeni, odgovorni, savjesni i motivirani šumarski radnici imaju odlučujuću ulogu u ostvarivanju uspješnih proizvodnih i poslovnih rezultata te čine neodvojivu sastavnicu u suvremenoj, općeprihvaćenoj paradigmi održivoga gospodarenja šumama. Međutim, danas u svijetu stalnih promjena šumarstvo se neprestano nalazi pred izazovom osiguranja kvalificirane i održive radne snage. Nedostatak šumarskih radnika postaje sve učestaliji problem u europskom i svjetskom šumarstvu, a razlog tomu su različiti globalni demografski, ekonomski, tehnološki i politički procesi, kao i specifičnosti samog sektora. U radu se stoga, uz opće značajke šumarskog rada prikazuju neki pokazatelji stanja i položaja radne snage u šumarstvu Europe i svijeta. Posebno se obrađuju aktualna pitanja i problemi u regrutiranju potrebne šumarske radne snage (nedostatak radnika, manjak interesa kod mladih ljudi, starenje postojeće radne snage, šumarski poduzetnici, neformalno zapošljavanje i sl.) te određeni alati i instrumenti važni za uspješno privlačenje i zadržavanje šumarskih radnika (razumijevanje motivacije, kompenzacije za rad, obrazovanje i trening radnika, nove tehnologije i sl.). Svrha rada se sastoji u pružanju podloga koje mogu biti važan doprinos u unapređenju stanja i održivosti radne snage u šumarstvu.
Odumiranjem stabala mijenjaju se stanišne prilike u šumskom ekosustavu, uslijed čega dolazi do promjene mikroklime i mikrobiološke aktivnosti tla. Cilj ovoga istraživanja je utvrditi razlike u ...mikroklimi staništa te u enzimatskoj aktivnosti šumskog tla u trima šumskim progalama i trima šumskim sastojinama obične jele s rebračom (Blechno-Abietetum Ht. 1950). Od mikroklimatskih elemenata mjerene su temperatura zraka, temperatura tla, relativna vlažnost zraka i volumetrijska vlažnost tla. Za određivanje kemijskih svojstava tla te dehidrogenazne i proteolitičke aktivnosti tala prikupljeni su kompozitni uzorci tla s dubine od 0 do 10 cm. U šumskim progalama utvrđene su značajno više vrijednosti temperatura zraka i tla te značajno niže vrijednosti relativne vlažnosti zraka i volumetrijske vlažnosti tla nego u šumskoj sastojini. Provedenim istraživanjem nisu utvrđene značajne razlike u kemijskim svojstvima tala između šumskih progala i sastojina. Zbog nesignifikantnih promjena kemijskih karakteristika tla, nisu utvrđene značajne promjene u enzimatskoj aktivnosti tala u progalama u odnosu na šumske sastojine. Temperatura zraka i temperatura tla povezane su s dehidrogenaznom aktivnosti tala, dok su temperatura tla i volumetrijska vlažnost tla povezane s proteolitičkom aktivnosti tala u šumskim progalama. Kemijska su svojstva tla također imale značajan utjecaj na enzimatsku aktivnost, jer se povećanjem udjela organske tvari, dušika, humusa i ugljika u tlu povećava i enzimatska aktivnost šumskih tala. Najveće korelacije enzimatske aktivnosti i kemijskih svojstava tla utvrđene su za proteolitičku aktivnost šumskih tala. Enzimatska aktivnost šumskih tala bila je najveća na početku vegetacijskog razdoblja u uvjetima optimalne temperature i vlažnosti tla.
With the decline of trees, habitat conditions change, resulting in changes in the microclimate and microbiological activity of the soil. The aim of the research is to determine the differences in the microclimate of habitats and in the enzymatic activity of forest soil in three forest gaps and three forest stands of silver fir with hard fern (Blechno-Abietetum Ht. 1950). Of the microclimatic elements, air temperature, soil temperature, relative air humidity and volumetric soil moisture were measured. Composite soil samples from a depth of 0 to 10 cm were collected to determine the chemical properties of the soil and the dehydrogenase and proteolytic activity of the soil. Significantly higher values of air and soil temperatures and significantly lower values of relative air humidity and volumetric soil moisture were found in forest gaps. The research did not reveal any differences in the chemical properties of the soil between forest gaps and stands. Due to insignificant changes in soil chemical characteristics, no significant changes in soil enzymatic activity were found in the gaps in relation to forest stands. Air temperature and soil temperature are related to soil dehydrogenase activity, while volumetric soil moisture is associated with proteolytic soil activity in forest gaps. Soil chemical characteristics also had a significant effect on enzymatic activity. By increasing the share of organic matter, nitrogen, humus and carbon in the soil, the enzymatic activity of forest soils also increases. The highest correlations between enzymatic activity and soil chemical characteristics were found for proteolytic activity of forest soils. The enzymatic activity of forest soils was highest at the beginning of the vegetation period under conditions of optimal soil temperature and soil moisture.
A continuous 2-D analytical drain current model of double-gate (DG) heterojunction tunnel field-effect transistors (HJTFETs) with a SiO 2 /HfO 2 stacked gate-oxide structures has been presented in ...this paper. The surface potential model has been developed by considering the effect of accumulation/inversion charges and depletion region at source/channel and drain/channel junctions. The electric field-dependent band-to-band tunneling generation rate has been derived from the surface potential model. The tangent line approximation method has been used to calculate the drain current of DG HJTFETs. The developed model is valid for all regions (subthreshold to strong accumulation/inversion region) of operation. The model has been developed for Si/Ge hetero and Si homojunction-based tunnel field-effect transistor devices. The model is also applicable for other structures such as III-V materials-based InAs/GaSb DG HJTFET and silicon-on-insulator-based HJTFET. The analytical model results are validated by 2-D ATLAS simulation data.
Visokogorsko područje dinarskog krša obilježeno je raznolikošću reljefnih formi, koje su u kombinaciji s humidnom klimom i različitim odnosima dolomita i vapnenaca, posebice u pogledu brzine i načina ...trošenja, dodatni izvor varijabilnosti fiziografije tla. U Nacionalnom parku Risnjak dimenzijama se ističu dvije ponikve (Viljska ponikva - VIP i Velika ponikva - VP) gdje smo testirali hipotezu o postojanju značajnih razlika u fiziografiji površinskog dijela tla. Cilj je bio istražiti u kojoj se mjeri uzduž osojne i prisojne padine ponikve mijenjaju kemijske značajke površinskog dijela tla i očituje li se pri tomu i razlika između dviju ponikvi, s obzirom na postojanje razlike u njihovoj litološkoj građi i poziciji unutar gorskog masiva. Istraživanja su provedena tako da je u svakoj ponikvi postavljen transekt u pravcu ~sjever-jug preko dna ponikve, na komu je obavljeno uzorkovanje tla do dubine od 15 cm (ili do stijene, ako je tlo pliće). Pokazalo se da je u VIP izraženija diferencijacija prirode humusa u organičnom horizontu i da ona dobro korespondira s diferencijacijom vegetacije. U VP se fizička trošivost stijena (dolomitični supstrat) odražava na fiziografiji tla u obliku karbonatnosti i više pH-vrijednosti, koja u VIP raste od dna prema rubu ponikve, dok se u VP pH-vrijednost značajno ne mijenja uzduž padina. Na osojnoj ekspoziciji u VIP je udio organskog ugljika u tlu značajno veći (377 g kg–1) od udjela na prisojnoj ekspoziciji (97 g kg–1), pri čemu na osojnoj ekspoziciji udio organskog ugljika opada od dna prema rubu ponikve, a na prisojnoj ekspoziciji se očituje blagi rast. Za razliku od navedonoga, u VP udjel organskog ugljika ima obrnuti trend. Slične odnose i trendove pokazuje i udjel ukupnog dušika, osim pri dnu osojne padine u VIP, gdje je Ntot relativno nizak, a Corg relativno visok. Zaključno, fiziografija tla dubokih gorskih ponikvi krša pod snažnim je utjecajem prirode stijena u pogledu dolomitičnosti. Tlo povrh dolomita i dolomitičnih vapnenaca obilježeno je karbonatnošću. U ponikvama u masivima čvrstih vapnenaca može se očekivati na njihovim osojnim padinama karakteristične trendove pH-vrijednosti tla te udjela organskog ugljika i ukupnog dušika zbog vrlo izraženog hidrotermičkog, odnosno bioklimatskog trenda. Na prisojnim ekspozicijama takvih ponikvi analogni trendovi s karakterističnim gradijentima izostaju, što korespondira i s izostankom prepoznatljivog vegetacijskog slijeda.
The high mountain area of the Dinaric karst is characterized by a variety of relief forms, which in combination with humid climate and different relationships of dolomite and limestone, especially in terms of rate and nature of weathering, are an additional source of variability of soil physiography. In the Risnjak National Park, two sinkholes stand out in terms of dimensions (Viljska ponikva - VIP and Velika ponikva - VP), where we tested the hypothesis of the existence of significant differences in the physiography of the surface part of the soil. The aim was to investigate the extent to which the chemical characteristics of the surface part of the soil change along the shady and sunny slopes of the sinkhole and whether the difference between the two sinkholes is evident, given the difference in their lithological structure (VIP is sinkhole in limestone and VP is sinkhole in dolomitic limestones and calcite dolomites) and positions within the mountain massif. The research was carried out in such a way that in each sinkhole a transect was placed in the direction north-south over the bottom of the sinkhole, on which soil sampling was performed to a depth of 15 cm (or to the rock, if the soil is shallower). Sampling was performed on rows of profiles in 5 replicates, which were placed perpendicular to the transect with a height difference of 10 m (Fig. 1). In each sinkhole, 22 rows of profiles were set up, on which 110 soil samples were collected, and the pH value, carbonate content, organic carbon content and total nitrogen content were measured on them. The research showed that on the shady slope in VIP, in addition to vertical vegetation differentiation, there is also a differentiation of the nature of humus in the organic horizon (hemimor, modermor, sphagnomor). This differentiation is much less pronounced in the VP, and on the sunny slope in both sinkholes it is almost absent. In VP, the physical weathering of rocks (dolomitic substrate) is reflected in the physiography of the soil in the form of free carbonate and higher pH values (Figs. 9 and 10). In VIP the pH rises from the bottom towards the edge of the sinkhole, both on the shady and sunny slope, while in VP the pH value does not change significantly, both along the shady and along the sunny slope. A recognizable factor in the spatial variability of carbonate content and pH value of this soil is phytopedoturbation in the form of tree felling and ejection of carbonate particles on the surface of the sinkhole slope, where they are exposed to gravitational and water erosion and further redistribution down the slope. At the shady slope in VIP, the share of organic carbon in the soil is significantly higher (377 g kg – 1) than the share at sunny slope (97 g kg – 1). At the shady slope the share of organic carbon decreases from the bottom to the edge of the sinkhole (Fig. 11), and a slight increase is evident on the sunny slope. In VP, the mean values on the slopes and the trends of these shares on the slopes in relation to VIP have the opposite relationship (Fig. 12). Similar relatios and trends are shown by the share of total nitrogen (Fig. 13), except at the bottom of the shady slope in VIP. Here, the share of Ntot is relatively low, and the share of Corg is relatively high, so only in this part within both transects does C/N differ significantly from the remaining parts of the transects (Fig. 14). In conclusion, the soil physiography of deep karst sinkholes is strongly influenced by the nature of the rocks in terms of dolomiticity. The soil above the dolomite and dolomitic limestones is marked by carbonates. In deep sinkholes in solid limestone massifs, characteristic trends of soil pH and the content of organic carbon and total nitrogen can be expected on their shady slopes due to a very pronounced hydrothermal and bioclimatic trend. Analogous trends with characteristic gradients are absent on the sunny slopes of such sinkholes, which corresponds to the absence of a recognizable vegetation sequence.
•SBS modifiers enhanced low-temperature crack resistance of asphalt binder.•High strain fatigue life of the SBS modified mastic asphalt mixtures was improved.•The SBS modified mixtures had greater ...flexural toughness than control mixtures.•The SBS modifiers was more substantial in retarding fatigue crack growth.
This study evaluated the fatigue performance of Styrene–Butadiene–Styrene (SBS) modified mastic asphalt mixtures used for bridge deck pavements. The effect of the type and content of newly developed SBS modifiers was investigated using typical binder tests. Four-point bending beam fatigue and indirect strength tests were conducted to examine fatigue and fracture behaviors of the SBS modified mastic asphalt mixtures. The SBS modifiers without CC double bonds enhanced the mechanical properties of the mastic asphalt binder and mixtures: lower stiffness after short- and long-term oxidation, significantly greater fatigue resistance at a higher strain level, and higher crack development resistance.
