Development and validation of force sensor

U ovom radu dokazana je teoretska ovisnost ulaznih i izlaznih veličina, te je konstruiran i umjeren mjerni pretvornik sile u uređaju za mjerenje mase tijela preko frekvencije napete žice. Teoretski su obrazložene karakteristike mjerenja, značajke mjernog pretvornika, te općenito potreba za istim. Istaknute su poteškoće tijekom izrade i umjeravanja, te su dane smjernice za daljnja istraživanja. U eksperimentalnom dijelu ovoga rada konstruirana je i umjerena frekvencijska vaga. Dokazana je funkcionalnost metode te su eksperimentalni podaci popratili teoretsku osnovu. Mjerenje je brzo i jednostavno, a rad može poslužiti kao osnova za daljnja istraživanja ovisnosti frekvencije i mase, odabira materijala, te dimenzioniranja i konstruiranja vagi na navedenom principu.In this paper, the theoretical dependence of input and output size is demonstrated, and force sensor in the device for measuring body mass over the frequency taut wire was designed and calibrated. Characteristics measurements, the transmitter features and generally need for them, are theoretically reasoned. Difficulties during the development and calibration are highlighted, and guidelines for further research are given. In the experimental part of this work, the frequency scale is designed and moderated. The functionality of the method is proven and experimental data covered the theoretical basis. Measurement is fast and simple, and the work can serve as a basis for further study of the frequency dependence and weight, material selection and dimensioning and construction of scales on the above principle

Development and validation of force sensor

U ovom radu dokazana je teoretska ovisnost ulaznih i izlaznih veličina, te je konstruiran i umjeren mjerni pretvornik sile u uređaju za mjerenje mase tijela preko frekvencije napete žice. Teoretski su obrazložene karakteristike mjerenja, značajke mjernog pretvornika, te općenito potreba za istim. Istaknute su poteškoće tijekom izrade i umjeravanja, te su dane smjernice za daljnja istraživanja. U eksperimentalnom dijelu ovoga rada konstruirana je i umjerena frekvencijska vaga. Dokazana je funkcionalnost metode te su eksperimentalni podaci popratili teoretsku osnovu. Mjerenje je brzo i jednostavno, a rad može poslužiti kao osnova za daljnja istraživanja ovisnosti frekvencije i mase, odabira materijala, te dimenzioniranja i konstruiranja vagi na navedenom principu.In this paper, the theoretical dependence of input and output size is demonstrated, and force sensor in the device for measuring body mass over the frequency taut wire was designed and calibrated. Characteristics measurements, the transmitter features and generally need for them, are theoretically reasoned. Difficulties during the development and calibration are highlighted, and guidelines for further research are given. In the experimental part of this work, the frequency scale is designed and moderated. The functionality of the method is proven and experimental data covered the theoretical basis. Measurement is fast and simple, and the work can serve as a basis for further study of the frequency dependence and weight, material selection and dimensioning and construction of scales on the above principle

New records of alien plants – Ludwigia peploides (Kunth) P. H. Raven, Reynoutria sachalinensis (F. Schmidt) Nakai and Nicotiana glauca Graham in Croatia

Invasive alien species Ludwigia peploides, Reynoutria sachalinensis and Nicotiana glauca, currently registered in Croatia with small number of records, were found during fieldwork undertaken mostly through the national monitoring of waters from 2018 to 2020. Ludwigia peploides was previously recorded only once in the River Ilova, the existing data for R. sachalinensis indicate only three confirmed findings, in Čabar, Karlovac and Donja Stubica, while the previous data for N. glauca include several localities in Central and Southern Dalmatia. The new records are as follows: two findings of L. peploides refer to the River Česma (Obedišće and Sišćani); three records of R. sachalinensis refer to Gorski Kotar (Gerovo and Čabar), while N. glauca is newly recorded in the Neretva River Valley (Krvavac) and the island of Krk. Despite their potential invasiveness, all three are still locally naturalized and currently their spread is very slow and limited in Croatia

Bryophyte flora of the Significant Landscape “Lower Kamenjak and Medulin Archipelago”(Istria, Croatia) with new and noteworthy national records

Bryophyte flora of the Significant Landscape Lower ”Kamenjak and Medulin Archipelago” in Istria (western Croatia) was studied from 2019 to 2021. The study resulted in a list of 14 liverwort and 60 moss taxa. Tortula pallida, Bryum gemmilucens, Microbryum davallianum var. conicum and Microbryum muticum are new national records. The prevalence of Mediterranean-Atlantic, temperate and southern-temperate chorotypes corresponds well with the biogeographical characteristics of the studied area. The turf life-form and colonist life strategy, predominantly represented by small Pottiaceae species, prevailed within the study. They mostly inhabited periodically moist soil of open habitats in olive groves, maquis and garrigues. This study aimed to address the significant lack of current data on bryophytes in coastal parts of Croatia

Širenje kritično ugrožene vrste Anthemis tomentosa L. (Asteraceae) u južnoj Istri

Croatian records of the critically endangered Anthemis tomentosa are very scarce. One population was known, from southernmost Istria, within the Significant Landscape Lower Kamenjak and Medulin Archipelago. First records from the 19th century were regarded as dubious, but the species was finally confirmed on Rt Franina (surroundings of Premantura) in the end of 90’ties. During our visits to southern Istria, we found four new localities of this species. The largest population was found in the area of Marlera (surroundings of Ližnjan), where A. tomentosa occurs along a four km long coastline. The species commonly occurs at the fringe between the coastal rock vegetation and calcareous grasslands, where the influence of salt spray is high. Observations have shown that A. tomentosa is threatened by anthropogenic influences and the population is spreading on Rt Franina since these influences have been reduced.Hrvatski nalazi kritično ugrožene vrste Anthemis tomentosa su vrlo rijetki. Samo jedna populacija bila je poznata u južnoj Istri, unutar zakonom zaštićenog značajnog krajobraza Donji Kamenjak i Medulinski arhipelag. Prvi nalazi iz 19. stoljeća navode se kao dvojbeni, no vrsta je konačno potvrđena na rtu Franina (okolica Premanture) krajem 90-tih godina. Tijekom naših posjeta južnoj Istri zabilježili smo ukupno četiri nova nalazišta. Najveće nalazište zabilježeno je na području Marlere (okolica Ližnjana), gdje je A. tomentosa rasla na području koje se proteže duž četiri km obalne linije. Vrsta uobičajeno dolazi na prijelazu između vegetacije obalnih stijena i travnjačke vegetacije, gdje je visok utjecaj posolice. Opažanja pokazuju da je vrsta ugrožena ljudskim aktivnostima i da se populacija na rtu Franina počela oporavljati kada je ovaj utjecaj smanjen

Novi nalazi rijetke hladnovodne zlatnožute alge Hydrurus foetidus (Villars) Trevisan (Chrysophyceae) u Hrvatskoj

Two new sites with benthic freshwater alga Hydrurus foetidus (Villars) Trevisan have been discovered in Dinaric Ecoregion of Croatia. The sites are located in two karst watercourses: Kupa River and Slušnica River. Both sites are non-shadowed aquatic habitats, with developed vegetation characteristic for clear, running waters. The alga was found during summer months at its disintegration stage, and during autumn at the beginning of its growing stage. In the Kupa River, incrusted calcium carbonate was found within the thalli of H. foetidus. After the first known record in Bijela Rijeka River from 2015, our findings represent the second and the third known localities of this species in Croatia. Even though the vegetation composition indicates high ecological status of the sites, future anthropogenic impacts and climatic changes could become a threat to this underexplored species in Croatia.Dva nova nalaza bentičke slatkovodne alge Hydrurus foetidus (Villars) Trevisan zabilježena su u dinarskoj ekoregiji u Hrvatskoj. Nalazi su locirani u dva krška vodotoka: rijeka Kupa i Slušnica. Na oba istražena nalazišta alga raste na nezasjenjenim staništima s vodenom vegetacijom makrofita karakterističnom za čiste tekuće vode. Alga je uočena tijekom ljeta u fazi raspadanja talusa te tijekom jeseni u početnoj fazi rasta. Na talusu jedinki iz rijeke Kupe primijećen je inkrustat kalcijevog karbonata. Nakon nalaza u Bijeloj rijeci 2015. godine, ovi nalazi predstavljaju drugi i treći nalaz ove rijetke vrste u Hrvatskoj. Iako sastav vegetacije ukazuje na vrlo dobro ekološko stanje na oba nalazišta, mogući antropogeni pritisci i klimatske promjene u budućnosti mogli bi ugroziti ovu nedovoljno istraženu vrstu u Hrvatskoj

Estimation of Bull.s Gene Effects for Milk Amount

In this paper we tried to estimate gene effects of three bulls that are mated with five populations of half-sisters by sire line for milk amount. We wanted to fortify whether the order of bull.s gene effects was unchangeable or it was modified. Totally we analyzed 2824 lactation. Investigation was made on two different generations of Holstein cows (mothers and daughters). Analysis of results for milk production of mothers showed that between different populations of mothers exist significant differences (P<0.05 and P<0.01). It was fortified that order of bulls wasn.t same i.e. that their breeding value (like sum of all present genes in one individual) was various on the different populations of cows

Zanimljivi dodaci flori doline rijeke Neretve ( južna Hrvatska) s naglaskom na vodene biljke

While working on several projects dealing with the flora of Neretva River delta in south Croatia, interesting floristic discoveries were made. During fieldtrips, freshwater habitats (rivers, channels and lakes) were in the focus of the survey, and were studied in detail both from the boat and from the mainland. Altogether 69 plant taxa were recorded and are presented in the results, out of which 25 taxa associated with aquatic habitats (hydrophytes, helophytes and species of riparian habitats) were discussed in more detail. These taxa are rare, threatened, invasive, newly found or otherwise seen as important for the studied area and their distribution maps are also presented.Tijekom rada na nekoliko različitih projekata koji uključuju istraživanje flore u dolini rijeke Neretve na jugu Hrvatske, zabilježeni su neki zanimljivi floristički nalazi. Tijekom terenskih izlazaka, u fokusu su bila slatkovodna staništa (rijeke, kanali i jezera) koja su bila detaljno istražena čamcima i s kopna. Zabilježeno je ukupno 69 biljnih svojti koje su prikazane u rezultatima, dok je 25 svojti prikazano i diskutirano detaljnije, a radi se o svojtama koje su u određenoj mjeri vezane za vodena staništa (hidrofiti, helofiti i vrste vlažnih staništa). Odabrane svojte su rijetke, ugrožene, invazivne, novo zabilježene ili su njihovi nalazi na drugi način zanimljivi za ovo područje, a prikazane su i njihove karte rasprostranjenost

Distribution and habitat characteristics of Vallisneria spiralis L. in Croatia

Eight new localities of the rare, strictly protected macrophyte Vallisneria spiralis have been recorded during a comprehensive survey of water bodies in Croatia. One record is located in the Mediterranean Region, in Butoniga Reservoir, while the remaining records are from the Continental Region, the majority of them situated along the Kupa River. Vallisneria spiralis occurred in slightly basic and alkaline environments and in a wide range of nutrient availability. In Continental localities, the species was present within Myriophyllo-Nupharetum luteae of the alliance Nymphaeion-albae, while in Butoniga it occurred within the vegetation of the alliance Potamogetonion. Prior to our research, the species was recorded in Croatia only twice, with the older record dating back to the 19th century and the second from recent years, but neither one was confirmed in later surveys. The low number of records of V. spiralis, in spite of a wide-ranging search through hundreds of localities, confirmed the rare status of this species, although the reasons for such limited distribution remain unclear, especially bearing in mind that suitable aquatic habitats are quite widespread in the country

Ponovni nalaz kopnene zelene alge Trentepohlia aurea (Linnaeus) C. Martius (Chlorophyta) u Hrvatskoj nakon 130 godina

The first record of the terrestrial green alga Trentepohlia aurea for Croatia was made in 1890 in the area of the Krka River, and has remained until this day the only record of this globally widespread species in the country. During studies related to aquatic vegetation, the species was finally rediscovered from the area of Plitvice Lakes, in the Gorski kotar region and near Vukova Gorica village, after 130 years during which no records were made. All recorded populations formed round, woolly, orange-red patches on the surface of rocks and concrete walls, partly forming a community with bryophytes and lichens. In some cases in these mixed communities, Trentepohlia thalli overgrew bryophytes blocking their access to nutrients, water and light. This long period of lack of records of T. aurea in Croatia is mostly a consequence of the discontinuity in research on certain algal groups in Croatia.Prvi nalaz kopnene zelene alge Trentepohlia aurea u Hrvatskoj potječe iz 1890. godine iz područja uz rijeku Krku, i do danas je to za Hrvatsku bio jedini nalaz ove globalno raširene vrste. Tijekom istraživanja vodene vegetacije vrsta je ponovno, nakon 130 godina, pronađena na području Plitvičkih jezera, u Gorskom kotaru, i blizu sela Vukova Gorica. Sve zabilježene populacije činile su okrugle, vunaste, narančasto-crvene nakupine na površini stijena i betonskih zidova, čineći djelomično zajednicu s mahovinama i lišajevima. U nekim slučajevima ovih miješanih zajednica, talusi alge Trentepohlia prerastali su mahovine, blokirajući im pristup nutrijentima, vodi i svjetlu. Dugački period bez nalaza alge T. aurea u Hrvatskoj većinom je posljedica prekida u istraživanjima nekih skupina algi