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Evaluating and Modeling of Chainsaw Noise Propagation by Using Artificial Neural Network in Selective Cutting
Get PDFThe investigation of the effects of the noise generated by harvesting equipment on the environment is one of the important topics in sustainable forestry. During timber harvesting, not only workers but also wildlife are exposed to the noise generated. Exposure to noise has both direct and indirect effects on humans and wildlife. The negative effects of noise exposure can be observed depending on its intensity and duration. Noise exposure, which has various psychological and physiological effects on humans, also negatively affects plants and animals. In this study, sound measurements of the chainsaw were conducted during thinning operations within the boundaries of the Alara Forest Management Directorate in Alanya, Antalya Province. The measurement area is a Turkish red pine (Pinus brutia Ten.) stand with a canopy density of 60–65%, a slope of 30–35%, and tree diameters ranging from 20 to 35 centimeters. The noise emitted by the chainsaw during production, ranging from approximately 1 meter to 200 meters, has been modeled using a feedforward Artificial Neural Network (FANN) for sound propagation. The measurement data was used 60% for training, 20% for testing, and 20% for validation. Random trees were assigned to noise attenuation effects on the sound according to the stand characteristics of the study area. Thus, it was aimed to create a realistic sound propagation model and estimation maps. The average performance metrics of the model, RMSE and R² values, were calculated as 4.84 and 0.88, respectively. According to the sound propagation model predicted by the FANN as a static model, it is estimated that the distance at which the chainsaw could affect wildlife behavior is 400 meters or less
Climatic, Hydrological and Air Quality Determinants of Black Alder (Alnus glutinosa [L.] Gaertn.) Ecological Niche Model in the Bosna River Basin
Get PDFIn Bosnia and Herzegovina, black alder appears in scattered smaller forest stands, fragments and patches that are still not spatially separated and allocated in management plans, despite its high ecological importance. The objective of this study is to model a black alder ecological niche considering combined effects of climate, hydrological and air quality determinants to support decision-making of conservation and restoration activities on a local/regional level. Black alder occurrence was registered on 72 temporary sample plots representing about 1500 trees in the Bosna River basin corresponding to Level 6, EU-Hydro River Network Database. Six climatic variables (average annual temperature, minimum temperature, maximum temperature, sum of temperature above 5°, sum of precipitation, maximum precipitation), five hydrological variables (average annual flow, minimum flow, maximum flow, flow between 1961–1990 and water level) and five air quality variables (average annual concentration of air particulate matter of PM2.5 and PM10 mm, SO2, NO2, maximum CO2) were interpolated spatially on 10 m grain size based on hydro-meteorological data from 13 national stations. The MaxEnt method was used to predict spatial distribution model, where predicted occurrence probabilities are classified in habitat suitability classes. The MaxEnt model revealed high-quality spatial prediction (AUC=0.95). The most significant determinants were average annual sum of precipitation and average annual 24-hour maximum CO2 concentration (cumulative about a 72% contribution). The highest occurrence probabilities were related to areas with less than 1400 mm of annual sum precipitation and elevated CO2 linked to low NO2. The areas with high species occurrence are mainly located in continental Bosnian Internal Dinarides in the valley and partly on hilly and sub-mountainous positions overlapping pedunculated oak-hornbeam and Illyrian sub-mountainous beech forests. Modeled ranges of precipitations and air variables concentrations indicate that black alder prefers continental low hilly and plane positions covering forest edges, although some suitable ecological niches are predicted in sub-urban and peri-urban green areas. The obtained model of species distribution determined spatially ecological niches important for conservation and restoration to maintain ecological services and biodiversit
Unlocking the Future of Travel – Understanding the Acceptance of Railway Passenger Services in Germany
No full textPassenger railway transport plays a crucial role in reducing carbon emissions from car use, making its increased adoption essential for meeting climate goals. This study examines the factors influencing the adoption and utilisation of rail transport in Germany, utilising the technology acceptance model (TAM) as a theoretical framework. The adapted model confirms the relevance of TAM in service-oriented contexts, identifying perceived usefulness and perceived ease of use as key drivers of acceptance. A notable finding is the gap between intention and actual behaviour. While many participants expressed a willingness to use rail services, this intention often failed to translate into regular use. This highlights a major challenge in promoting sustainable mobility, as positive attitudes alone are insufficient to shift travel behaviour. The study provides valuable insights for rail service providers seeking to enhance usage and improve public perception. However, limitations must be acknowledged. The sample may not fully reflect the broader population, and a potential selection bias, such as a high proportion of car owners, may affect generalisability. Despite these issues, the study contributes to the literature on TAM in consumer services and underscores the need for further research into the factors influencing the gap between intention and action
ANALIZA STABILNOSTI KANALA BUŠOTINE NA TEMELJU HOEK-BROWNOVA KRITERIJA LOMA KORIŠTENJEM GEOMEHANIČKIH JEDINICA I PROCJENE DISKONTINUITETA
No full textThe accuracy of wellbore instability assessment becomes reliable when sufficient geomechanical model data and appropriate failure criteria parameters are used. The Hoek-Brown failure criterion is widely used in wellbore instability analysis; however, limited focus has been given to parameter determination and the specific conditions for its application (intact rock or rock mass) within wells. In this study, theoretical wellbore analysis was conducted using various failure criteria, with a primary focus on comparing the Hoek-Brown criterion for both intact rock and rock mass conditions. A geomechanical model was developed using petrophysical logs, laboratory tests, and downhole measurements. The geomechanical units of the wellbore were determined through clustering algorithms, supported by downhole plugs. Natural discontinuities within the wellbore were identified using image logs, and their distribution was mapped for each geomechanical unit. The parameters for intact rock in the Hoek-Brown criterion were derived from laboratory test results, while those for the rock mass condition were determined using the rock mass rating (RMR) and geological strength index (GSI). The results indicate that applying the Hoek-Brown criterion assuming intact rock does not provide a reliable estimation of wellbore instability. However, by using the criterion under rock mass conditions, wellbore failures can be accurately predicted according to the wellbore conditions. Additionally, evaluating the wellbore conditions based on geomechanical units improves the theoretical analysis’s accuracy and identifies stable and unstable zones.Točnost procjene stabilnosti kanala bušotine postaje pouzdana kada se koristi dovoljno podataka geomehaničkoga modela i odgovarajući kriteriji za predviđanje loma stijena. U analizi stabilnosti kanala bušotine često se koristi Hoek-Brownov kriterij; međutim, malo je pozornosti posvećeno određivanju parametara i specifičnih uvjeta za njegovu primjenu (netaknuta stijena ili stijenska masa) unutar bušotina. U ovome je radu provedena teorijska analiza stabilnosti kanala bušotine primjenom raznih kriterija za predviđanje loma stijena s primarnim fokusom na usporedbu Hoek-Brownova kriterija za uvjete netaknute stijene ili stijenske mase. Razvijen je geomehanički model korištenjem rezultata petrofizičkih svojstava stijena, laboratorijskih testova i karotažnih mjerenja u bušotinama. Geomehaničke jedinice kanala bušotine određene su primjenom klasterskih algoritama, uz podršku sondi u bušotini. Prirodni diskontinuiteti unutar bušotine utvrđeni su snimanjem stijenki kanala bušotine (engl. image logs), a njihova je distribucija mapirana za svaku geomehaničku jedinicu. Parametri za netaknutu stijenu u Hoek-Brownovu kriteriju dobiveni su iz rezultata laboratorijskih testova, dok su oni za uvjete stijenske mase određeni pomoću RMR klasifikacije stijenske mase (engl. rock mass rating, RMR) i geološkoga indeksa čvrstoće (GSI). Rezultati pokazuju da primjena Hoek-Brownova kriterija uz pretpostavku netaknute stijene ne pruža pouzdanu procjenu stabilnosti kanala bušotine. Međutim, korištenjem toga kriterija u uvjetima stijenske mase mogu se točno predvidjeti nestabilnosti kanala bušotine s obzirom na uvjete u bušotini. Osim toga, procjena uvjeta u bušotini na temelju geomehaničkih jedinica poboljšava točnost teorijske analize i omogućava identifikaciju stabilnih i nestabilnih zona
Core and frame insulation of power transformers - Part I: History, past and present issues
Get PDFThis paper reviews the evolution of core and frame (clamp) insulation failures in power transformers and examines representative fault cases attributable to manufacturing defects, transportation-related displacement of the active part, and in-service malfunctions. Drawing on historical experience and recent field evidence, it shows how dominant failure mechanisms have shifted over time, from degraded insulation of bolted core assemblies to increasingly consequential core-ground and multipoint-grounding faults that can drive circulating currents, localized overheating, and abnormal gas generation. The study underscores the need for continued, systematic, and comparable data collection on core damage to strengthen root-cause attribution and improve prevention strategies. To reduce recurrence and enhance diagnosability, the authors recommend standardizing a robust, monitorable grounding design for transformer cores and frames, particularly for units rated 10 MVA and above
Mechanical complications of myocardial infarction: a retrospective analysis of five-year experience at the Slavonski Brod General Hospital
No full textSatellite monitoring of marine litter in the Adriatic Sea during 2015–2021
No full textAim: To analyze the spatiotemporal distribution and accumulation patterns of floating marine litter in the Adriatic Sea from 2015 to 2021 using satellite observations, with particular focus on identifying regional variability and dominant transport mechanisms.
Methods: In this observational study, we used satellite data from the Copernicus Sentinel-2/MultiSpectral Instrument L1C system to estimate marine litter presence across the Adriatic Sea from July 2015 to September 2021. The dataset includes records of pixels per litter windrow (PLW), representing spectral reflectance indicators of floating plastic-like debris. We performed analyses on annual and monthly scales, focusing on four zones: Italy (zones A and B), Croatia (zone C), and Albania (zone D). We assessed variability using boxplot metrics and interpreted spatiotemporal patterns in the context of oceanographic features, wind patterns, and riverine inputs.
Results: Zone A had consistently higher PLW values across the study period, making it the most polluted area. Litter was probably transported along the western Adriatic coast by the Western Adriatic Current (WAC) toward the south, with partial redistribution toward the eastern coast. Zones B and D showed pronounced annual and seasonal variability, with peaks in 2017, 2019, and 2021, while zone C showed less consistent patterns. Monthly trends revealed increased litter presence in warmer months, coinciding with higher tourist activity and riverine discharges. There was a marked increase in the PLW difference between zones A and B in two periods, 2015–2017 and 2018–2021, potentially due to litter sinking, WAC meandering, or cleanup efforts.
Conclusions: Satellite remote sensing can help us identify marine litter hotspots and understand their seasonal and spatial dynamics. Our findings highlight persistent pollution in the northern Adriatic and the role of currents and riverine inputs in shaping litter distribution. Long-term monitoring and integrated waste management strategies are essential for effective mitigation
Anti-NMDA Receptor Encephalitis in an Elderly Patient – A Case Report
No full textCilj: Prikazati slučaj pacijentice s anti-NMDA receptorskim encefalitisom te ukazati na težinu prepoznavanja ove bolesti, prolazeći cjelokupan diferencijalno-dijagnostički put pacijentice od prvog javljanja liječniku. Prikaz slučaja: Pacijentica u dobi od 66 godina zaprimljena je na neurološki odjel zbog novonastalih epileptičkih napadaja. S obzirom na nalaz magnetske rezonancije (MR) mozga, smatralo se da se radi o simptomatskoj epilepsiji kao posljedici ishemijske bolesti mozga te je uvedena adekvatna antiepileptička terapija. Nakon sedam mjeseci provedeno je neuropsihološko testiranje zbog subjektivnih tegoba zaboravnosti i zabrinutosti. Testiranjem su primijećeni ispadi vizuokonstruktivnih funkcija s desnostranim vidnoprostornim neglektom, bez dinamike u nalazu kontrolnog neuroradiološkog ispitivanja, što je odgovaralo prethodno postavljenoj dijagnozi. Nakon pet mjeseci pacijentica je ponovno hospitalizirana zbog serije epileptičkih napada, praćenih pogoršanjem govora i promjenama ponašanja. Uz primjenu antiepileptičke terapije, napravljene su dodatne pretrage radi etiološkog razjašnjenja polimorfnih tegoba. Standardni elektroencefalografski (EEG) nalaz ukazivao je na encefalopatiju. Imunohistokemijskim bojenjem pronađene su pozitivne oligoklonalne trake u likvoru, a probirom na prisutnost paraneoplastičnih antitijela likvor je bio pozitivan na povišen titar anti-NMDAR antitijela. Na temelju kliničke slike i rezultata dodatnih ispitivanja potvrđeno je da se radi o autoimunom encefalitisu posredovanom anti-NMDAR antitijelima. Pacijentica je liječena višemodalnom imunosupresivnom terapijom uz pozitivan terapijski odgovor na kognitivni status. Zaključak: Iako se anti-NMDA receptorski encefalitis prvotno opisivao kao dio paraneoplastičnog sindroma, danas je jedan od najčešćih uzroka nevirusnog encefalitisa. Brzina prepoznavanja i adekvatno liječenje ključni su za preživljavanje i povratak funkcionalnosti, stoga je važno senzibilizirati mlade kliničare da posumnjaju na ovu bolest, posebno kod starijih pacijenata.Aim: To present a case of a patient with anti-NMDA receptor encephalitis and highlight the importance of recognizing this disease by going through the entire differential diagnostic process from the patient’s first visit to the physician. Case report: A 66-year-old female patient was admitted to the neurology department due to newly developed epileptic seizures. Based on the magnetic resonance imaging (MRI) findings of the brain, it was believed to be symptomatic epilepsy resulting from ischemic brain disease, and appropriate antiepileptic therapy was initiated. After seven months, neuropsychological testing was performed due to subjective complaints of memory loss and anxiety. The testing revealed impairments in visuoconstructive functions with right-sided visuospatial neglect, with no changes in the follow-up neuroimaging findings, which corresponded to the previously established diagnosis. After five months, the patient was re-hospitalized due to a series of epileptic seizures, accompanied by worsening speech and behavioural changes. In addition to antiepileptic therapy, further investigations were conducted to clarify the aetiology of the polymorphic symptoms. Standard electroencephalogram (EEG) findings indicated encephalopathy. Positive oligoclonal bands were found in the cerebrospinal fluid through immunohistochemical staining, and screening for the presence of paraneoplastic antibodies showed a positive finding in the cerebrospinal fluid (CSF) for elevated titres of anti-NMDAR antibodies. Based on the clinical picture and additional test results, it was confirmed that the patient had autoimmune encephalitis mediated by anti-NMDAR antibodies. The patient was treated with multimodal immunosuppressive therapy with a positive therapeutic response in cognitive status. Conclusion: Although anti-NMDA receptor encephalitis was initially described as part of a paraneoplastic syndrome, it is now one of the most common causes of non-viral encephalitis. The speed of recognition and appropriate treatment are crucial for survival and return to functionality; therefore, it is important to sensitize young clinicians to suspect this disease, especially in older patients
Renal Infarction: A Case Report
No full textCilj: Cilj je ovog članka prikazati evalvaciju i dijagnostičko-terapijske mogućnosti na temelju iskustva i do sada poznatih slučajeva. Infarkt bubrega rijetko je stanje u hitnoj medicini koje je je uzrokovano potpunom ili djelomičnom okluzijom bubrežne arterije. Tipično se prezentira jakom boli u lumbalnoj regiji, hematurijom, oligurijom, arterijskom hipertenzijom i febrilitetom, no u većini slučajeva oponaša druge patologije među kojima su najčešće pijelonefritis i bubrežne kolike. Zbog svoje rijetkosti i nespecifičnosti kliničke slike često se krivo ili kasno dijagnosticira što može rezultirati ireverzibilnim oštećenjem bubrežnog parenhima, renovaskularnom hipertenzijom ili povećanjem rizika od embolijskih incidenata drugih organa. Prikaz slučaja: Osamdesetpetogodišnji pacijent primljen je na Objedinjeni hitni bolnički prijam zbog boli u abdomenu koja traje tri dana. Prilikom trijaže pacijent je bio urednih vitalnih parametara, febrilan 37,8 ⁰C. U fizikalnom statusu isticala se palpatorna bolnost u području desnog hemiabdomena uz lokalni defans. Laboratorijski nazali ukazali su na leukocitozu s pretežnom neutrofilijom te povišene vrijednosti C-reaktivnog proteina. Bubrežni parametri bili su unutar referentnih vrijednosti. Analizom urina utvrđena je proteinurija i hematurija. Budući da su radiogram grudnih organa, abdomena i orijentacijski ultrazvuk abdomena bili uredni, ordiniran je CT abdomena kojim se postavila dijagnoza infarkta desnog bubrega. Pacijent je potom hospitaliziran na Klinici za urologiju gdje je konzervativno liječen antikoagulantnom terapijom te je nakon poboljšanja općeg stanja otpušten nakon devet dana hospitalizacije. Zaključak: Ovaj slučaj pokazuje važnost ranog prepoznavanja simptoma i započinjanja terapije bolesnika sa simptomima infarkta bubrega kako bi se izbjegla potencijalna smrtnost i ireverzibilna ozljeda bubrega.Aim. This case report aims to present the evaluation and diagnostic-therapeutic possibilities of a patient with renal infarction. Acute renal infarction is a rare emergency condition caused by complete or partial occlusion of the renal artery. It may present with flank pain, hematuria, oliguria, arterial hypertension, and febrility. In most cases, it mimics other pathologies especially pyelonephritis and renal colic. Due to the non-specificity of the clinical presentation, it is often misdiagnosed or late diagnosed, which can lead to irreversible damage to the renal parenchyma, renovascular hypertension, or an increase in the risk of embolic incidents in other organs. Case report: An 85-year-old man came to the Emergency Department because of flank pain that had lasted for three days. The patient's vital parameters were normal except for febrility 37.8⁰C. During the physical examination, the abdomen was painful on palpation in the right hemiabdomen with local defense. Laboratory tests revealed leukocytosis with predominant neutrophilia and elevated C-reactive protein. The findings of renal parameters were within reference values. Urinalysis revealed proteinuria and hematuria. The radiogram of the chest organs, abdomen, and orientational ultrasound of the abdomen was normal, so the patient was prescribed a CT scan of the abdomen, which showed a renal infarction. The patient was hospitalized in the Department of Urology where he was treated with anticoagulant therapy and was discharged after 9 days in healthy condition. Conclusion: This case shows the essential importance of early recognition of symptoms and therapy initiation of patients with renal infarction to avoid potential mortality and irreversible kidney injury