29 research outputs found

    On energy efficiency of inland waterway self-propelled cargo vessels

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    Da bi se u fazi projektovanja broda analizirao uticaj forme i primenjenih tehničkih reÅ”enja na energetsku efikasnost, potkomitet IMO-a zadužen za zaÅ”titu životne sredine (MERS) predložio je u uvođenje tzv. indeksa energetske efikasnosti pri projektovanju (EEDI). Predloženi pokazatelj predstavlja odnos mase ugljen-dioksida emitovanog u atmosferu, i količine tereta koja je pri tome prevezena po kilometru. Za neke tipove morskih brodova već su razvijene jednačine koje određuju referentne vrednosti za EEDI. U ovom radu je predstavljen jedan od prvih pokuÅ”aja procene vrednosti ovog indeksa za rečne samohodne teretne brodove. U toku istraživanja su sprovedena ispitivanja rečnih samohotki na plovnom putu u realnim okolnostima. ProÅ”irena je baza podataka i na osnovu nje je razvijen novi matematički model za procenu potrebne snage motora u zavisnosti od osnovnih dimenzija broda i ograničenja plovnog puta. Analizirane su i značajne razlike između rezultata modelskih ispitivanja i ispitivanja brodova u prirodnoj veličini, a na osnovu čega je procenjena vrednost tzv. dodatka za službu. U radu je predložen približan postupak za određivanje koeficijenata propulzije na osnovu ispitivanja apsorpcije snage broda. Konačno, nagoveÅ”ten je način na koji se mogu odrediti referentne vrednosti indeksa EEDI koje bi mogle da se koriste pri projektovanju brodova ovog tipa.The Energy Efficiency Design Index (EEDI) was introduced by IMO - Marine Environment Protection Committee in order to stimulate innovation and technical development of all elements that influence energy efficiency of a ship from its design phase. According to definition, it represents weight of shipā€™s CO2 emissions per transport work. Baseline equations for EEDI were developed for several most common types of seagoing ships. This paper presents one of the first attempts to evaluate EEDI of inland-waterway, dry-cargo, self-propelled vessels. Within research that is explained in the paper, full-scale measurements were performed with the purpose to enrich the database according to which new mathematical model for power evaluation was developed. Large differences between the model- and full-scale measurements were also analysed. Finally, application of relatively large power margins for inland-waterway ships was suggested. EEDI baseline can be used as a benchmark of future ship designs

    Resistance Prediction for Hard Chine Hulls in the Pre-Planing Regime

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    A mathematical representation of calm-water resistance for contemporary planing hull forms based on the USCG and TUNS Series is presented. Regression analysis and artificial neural network (ANN) techniques are used to establish, respectively, Simple and Complex mathematical models. For the Simple model, resistance is the dependent variable (actually R/Delta for standard displacement of Delta = 100000 lb), while the Froude number based on volume (F-nV) and slenderness ration (L/V-1/3) are the independent variables. In addition to these, Complex model's independent variables are the length beam ratio (L/B), the position of longitudinal centre of gravity (LCG/L) and the deadrise angle (beta). The speed range corresponding to F-nV values between 0.6 and 3.5 is analyzed. The Simple model can be used in the concept design phases, while the Complex one might be used for various numerical towing tank performance predictions during all design phases, as appropriate

    Resistance Prediction for Hard Chine Hulls in the Pre-Planing Regime

    Get PDF
    A mathematical representation of calm-water resistance for contemporary planing hull forms based on the USCG and TUNS Series is presented. Regression analysis and artificial neural network (ANN) techniques are used to establish, respectively, Simple and Complex mathematical models. For the Simple model, resistance is the dependent variable (actually R/Delta for standard displacement of Delta = 100000 lb), while the Froude number based on volume (F-nV) and slenderness ration (L/V-1/3) are the independent variables. In addition to these, Complex model's independent variables are the length beam ratio (L/B), the position of longitudinal centre of gravity (LCG/L) and the deadrise angle (beta). The speed range corresponding to F-nV values between 0.6 and 3.5 is analyzed. The Simple model can be used in the concept design phases, while the Complex one might be used for various numerical towing tank performance predictions during all design phases, as appropriate

    Varijabilnost agronomskih osobina hibrida kukuruza pod uticajem faktora sredine

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    In this study 36 maize hybrids of different FAO maturity groups were observed in three successive years (2011, 2012 and 2013), on 8 locations. The main objective of this experiment was to observe the GxE interaction concerning yield, grain moisture, grain yield per ear and test weight. The experiment was set up according to the RCBD. Based on the obtained results average estimates, CV and overall ranking of hybrids were calculated. ANOVA was applied in order to estimate the effect of factors: genotype, environment and interaction. Thus the significance of all these factors was observed. Results of this research indicate the importance and necessity of performing multilocation and multiyear trials with the aim of observation and understanding the intensity of GxE interaction, as well as its influence on the grain yield and it components.Istraživanje je obuhvatilo 36 hibrida različitih FAO grupa zrenja, u 2011, 2012 i 2013 godini, na 8 lokaliteta. U ogledu je ispitivana interakcija genotip x sredina u pogledu stabilnosti prinosa zrna, vlage zrna, težine zrna po klipu i zapreminske mase kukuruza. Ogled je bio postavljen potpuno slučajnom blok sistemu (RCBD). Na osnovu dobijenih podataka izračunate su prosečne vrednosti, pokazatelji varijabilnosti posmatranih osobina i ukupan rang hibrida, a analizom varijanse utvrđena je značajnost efekta genotipa, sredina i interakcija. Za sve proučavane agronomske osobine, analizom varijanse su utvrđene statistički visokoznačajne vrednosti genotipa, sredina i interakcije. NajviÅ”i prosečan prinos zrna u ogledu ostvaren je u 2011. godini (11,62 t/ha), a najniži u 2012. godini (6,90 t/ha). Najniži prosečan procenat vlage zrna kukuruza u ogledu ostvaren je u veoma suÅ”noj 2012. godini (14,86%), dok između vrednosti ostvarenih u 2011. godini (19,47%) i 2013. godini (19,52%) nije bilo značajnije razlike. Vrednosti težine zrna po klipu kukuruza bile su direktno srazmerne vrednostima prinosa. Najveća zapreminska masa zrna kukuruza ostvarena je u suÅ”noj 2012. godini (74,84 kg/hl), dok je najmanje izmerena u kiÅ”ovitoj 2013. godini (70,47 kg/hl). Rezultati ovog istraživanja potvrđuju neophodnost izvođenja viÅ”elokacijskih i viÅ”egodiÅ”njih ogleda u cilju Å”to boljeg sagledavanja intenziteta interakcija genotip x sredina, i njihovog uticaja na prinos i komponente prinosa hibrida kukuruza različitih FAO grupa zrenja na teritoriji Srbije. Da bi proizvodnja kukuruza bila stabilna, farmerima koji nemaju mogućnost navodnjavanja, već kukuruz gaje u suvom ratarenju, treba savetovati da seju hibride različite dužine vegetacije

    Hydrocephalus-history of surgical treatment over the centuries

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    To trace the history of the treatment of hydrocephalus is to document the parallel development of medicine as a whole; when one reviews the treatment of hydrocephalus, the integral relationship between basic science and therapy is reaffirmed. The treatment of hydrocephalus, over the centuries, underwent three stages of evolution. Prior to the late 19 th century, treatment for 'water on the brain' involved more observation than intervention. During antiquity, middle ages and renaissance, hydrocephalus was not understood. Medical treatment was useless; surgery was hopeless. The second stage extends from the 19th century to the end of the first half of the 20 th century. Cerebrospinal fluid circulation was now understood; surgery however, remained inefficient, but some patients survived with arrested hydrocephalus. The third stage begins in the nineteen fifties with the development of silicone shunts with a valve. Surgery transforms the prognosis of hydrocephalus, but the number of post-operative complications creates new problems. The different attempts that have been made during these past two decades to solve these problems are reviewed. They have resulted in a reduction of the mechanical and infectious complications. CSF over drainage has been minimized. Percutaneous ventriculo-cisternostomies have in some cases replaced shunts. In the future, to improve outcome in these hydrocephalics, surgery, when indicated, should be performed as early as possible. Knowledge and prevention of the causes of hydrocephalus should be developed. As we progress further in this new millennium, it is appropriate to reflect on the past understanding and treatment of this disorder, review strategies to curb this disease process, and consider therapies and possibly cures that will be available in the future

    Grupe zrenja i potencijal rodnosti ZP hibrida kukuruza

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    Maize is one of the most important agricultural crops in the world, and also in our country. In Serbia, in last two decades maize is grown on the area from 1.2 to 1.3 million hectares, with the average production of 5.7 million tones per year. It is the fact that there are favorable natural conditions for its production in our country, but the grain yield fluctuates depending on rainfall quantities and especially rainfall disposition during the vegetation period. The purpose of this work is to establish the grain yield potential of ZP maize hybrids from FAO 400-700 maturing groups. Data from STRIP trails of six ZP maize hybrids (ZP 434, ZP 578, ZP 677, ZP 680, ZP 684 and ZP 704), from 16 locations during 3 years, are used in this work. Grain yield and grain moisture content were measured in six tested genotypes and analyze of variance was done with ANOVA statistical software. Results of this investigation showed that the hybrid ZP 434 had an average grain yield of 8.528 tĀ·ha-1, which is not statistically significantly different from the grain yield of the hybrid ZP 684 which yielded 8.626 tĀ·ha-1. At the same time, hybrid ZP 434 had the statistically significantly higher grain yield than the hybrids from FAO 700 maturing group. According to the presented results of lasting several years averages on several locations, we can conclude that the hybrids from FAO 400 maturing group have a grain yield potential at the same level as the hybrids from FAO 600-700 maturing group.Kukuruz je jedan od najznačajnijih ratarskih useva ne samo u svetu već i u naÅ”oj zemlji. U Srbiji se kukuruz u poslednje dve decenije gaji na povrÅ”inama od 1.2 do 1.3 miliona hektara, uz ostvarenu prosečnu proizvodnju od 5.7 miliona tona godiÅ”nje. Poznato je da kod nas postoje povoljni prirodni uslovi za njegovu proizvodnju, ali i to da su po godinama velika kolebanja prinosa zbog velike varijabilnosti u količini, a posebno u rasporedu padavina u toku vegetacije. Cilj ovog rada je da se utvrdi potencijal rodnosti ZP hibrida kukuruza, FAO grupa zrenja 400-700. U radu su koriŔćeni podaci proizvodnih STRIP ogleda Å”est ZP hibrida kukuruza (ZP 434, ZP 578, ZP 677, ZP 680, ZP 684 i ZP 704) sa 16 lokaliteta u toku tri godine. Praćen je prinos zrna i sadržaj vlage u zrnu Å”est ispitivanih genotipova, a analiza varijanse urađena je pomoću statističkog programa ANOVA. Rezultati istraživanja su pokazali da je hibrid ZP 434 ostvario prosečan prinos zrna od 8.528 tĀ·ha-1 koji se nije statistički značajno razlikovao od prinosa zrna hibrida ZP 684 od 8.626 tĀ·ha-1. U isto vreme hibrid ZP 434 imao je statistički značajno viÅ”i prinos nego hibridi FAO grupe zrenja 700. Na osnovu iznetih rezultata viÅ”egodiÅ”njeg proseka na viÅ”e lokacija može se zaključiti da hibridi FAO grupe zrenja 400 imaju potencijal rodnosti na nivou hibrida FAO grupe zrenja 600-700

    Genetička divergentnost samooplodnih linija kukuruza i heterozis

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    The genetic diversity of six maize inbred lines, as well as, the genetic similarity between parental inbred lines and heterosis for yield in their F1 crosses was studied. Three inbred lines (ZPL 142, ZPL 680 and ZPL 357/3) are of the BSSS origin and another three (ZPL 257/3, ZPL 17/5 and ZPL 173/3) are of the non-BSSS genetic background. Molecular markers provide a direct determination of a number for which two inbred lines are different for a given number of loci. Maize inbred lines were genetically characterized with RAPD markers. Genetic similarity among genotypes was done by a statistical analysis with NTSYSpc v2.0 and by the application of the cluster analysis. Parental inbred lines, 30 F1 crosses with reciprocals, were included in a randomized complete block design with four replications in two densities (44,640 and 64,935 plants ha-1) at the location of Zemun Polje in 2003 and 2004. The differences among genotypes (F1 and inbreds line per se), densities and years were statistically significant. The highest value of mid-parent heterosis (192.2 %), as well as, the best-parent heterosis (178.0 %) was obtained for the cross ZPL 173/3 x ZPL 680 over investigated densities and years. The Spearman's correlation coefficient was used to determine correlations between the values of heterosis obtained in the field experiment and the value of genetic distances based on RAPD markers. The obtained results indicate that RAPD markers can be used to study the genetic diversity of maize inbred lines, although their application in the prediction of heterosis for grain yield is limited.U radu je ispitivana genetička različitost Å”est samooplodnih linija kukuruza na osnovu RAPD markera i odnos genetičke sličnosti između roditeljskih linija i heterozisa za prinos zrna u njihovim ukrÅ”tanjima (F1 hibridima). Roditeljske linije i 30 F1 hibrida, dobijenih ukrÅ”tanjem roditeljskih linija u potpunom dijalelu, su testirani po slučajnom blok dizajnu sa četiri ponavljanja u dve gustine useva (G1=44.640 i G2=64.935 biljaka ha-1) u Zemun Polju tokom 2003 i 2004. godine. Razlike u prinosu zrna između ispitivanih genotipova (F1 i samooplodne linije per se), ispitivanih gustina i spoljnih sredina su bile statistički značajne. Najveći heterozis dobijen je kod kombinacije ZPL 173/3 x ZPL 680 i u odnosu na vrednost srednjeg roditelja (192.2 %) i u odnosu na boljeg roditelja (178.0 %) u ispitivanim gustinama i godinama. Za određivanje korelacija između vrednosti za heterozis u kombinacijama dobijenim u poljskom ogledu i vrednosti genetičkih distanci izračunatih na osnovu RAPD markera koriŔćen je Spearman-ov koeficijent korelacije. Dobijeni rezultati ukazuju da se RAPD markeri mogu koristiti za ispitivanje genetičke divergentnosti samooplodnih linija kukuruza, mada je njihova primena za predviđanje heterozisa za prinos zrna ograničena

    Međuzavisnost oscilacija i tranzijenata indukcionih procesa zakasnele fluorescencije hlorofila u tilakoidnoj membrani intaktnog lista kukuruza - reakcije na delovanje viÅ”ih temperatura i suÅ”e

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    Standard induction processes of delayed fluorescence (DF) of chlorophyll (induction signals) occur when an intact leaf segment of maize inbreds and hybrids is kept in the phosphoroscope darkroom for more than 15 minutes (t > 15 min), and at the same time the leaf is illuminated with the intermittent white light. Resolved induction processes of DF chlorophyll into transients: A, B, C, D and E occur when the intact leaf segment of maize inbreds and hybrids is kept in the phosphoroscope darkroom for a significantly shorter period (500 s > t > 30 s), with the time rate t of 30 s, prior to its illumination with the intermittent white light. Induction transients: A, B, C, D and E are characterized with the time of their generation: tA = 31Ā±6 ms (A), tB = 5 Ā± 0,5 s (B), tC = 15Ā±5 s (C), tD = 360Ā±20 s (D) and tE = 670Ā±35 s (E), dynamics of changes in transients intensities (IA, IB, IC, ID and IE) and mechanisms of their generation. The induction processes of chlorophyll DF of the intact leaf of maize inbreds and hybrids resolved into transients: A, B, C, D and E are accompanied by the occurrence and different levels of activation energy (Ea, kJ mol-1) that correspond to critical temperatures ranging from 28 to 33Ā°C. The generation mechanisms of induction transients A, B, C, D and E classify them into two groups. Transients A and B are of a physical character, while the transients: C, D, and E are of a chemical character. It is shown that the generation of the induction transients: B, C, D and E simultaneously follows establishing of the oscillations of induction processes of the DF chlorophyll. Oscillating of induction processes of DF chlorophyll is explained by the ion (K+, Na+, H+, Cl-) transport mechanism across the thylakoid membrane of the intact leaf of maize inbreds and hybrids grown under conditions of air drought, increased temperatures and water deficiency in the medium.U ovom radu ostvaruje se primena poboljÅ”anog fotosintetično-fluorescentnog metoda u proučavanju složenih indukcionih procesa zakasnele fluorescencije (ZF) hlorofila, koji su razloženi na tranzijente: A, B, C, D i E i kod kojih mogu da nastanu oscilacije. Međuzavisnost oscilacija i indukcionih tranzijenata: A, B, C, D i E javlja se kod intaktnih listova linija (ZPR 70ž i Oh 43) i hibrida (ZPDC 360, ZPSC 46A, ZPSC 704 i ZPSC 71) kukuruza koji su gajeni u staklari u uslovima različite vazduÅ”ne suÅ”e, delovanja viÅ”ih temperatura i deficita vode u podlozi. Posebno se ukazuje na uslove pri kojima dolazi do uspostavljanja standardnih indukcionih procesa ZF hlorofila. Daje se kraći opis standardne indukcione krive ZF hlorofila. Znatno detaljnije daju se eksperimentalni rezultati o razlaganju indukcionih procesa ZF hlorofila na tranzijente: A, B, C, D i E. Pokazani su vremenski i fizičko-hemijski parametri za proučavane indukcione tranzijente. ObjaÅ”njeni su njihova priroda i mehanizmi nastajanja. Utvrđene su karakteristike i mehanizam nastajanja oscilacija indukcionih procesa ZF hlorofila. Dati su uslovi pri kojima dolazi do pojave pobuđenog stanja, nastajanja fluktuacija i uspostavljanja oscilacija indukcionih procesa ZF hlorofila u tilakoidnoj membrani intaktnog lista linija i hibrida kukuruza. Izneta je hipoteza o mehanizmu nastajanja oscilacija. ObjaÅ”njena je međuzavisnost uspostavljanja oscilacija i tranzijenata indukcionih procesa ZF hlorofila

    Evaluation of maize grain yield and yield stability by ammi analysis

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    Significant genotype x environment interaction for quantitative traits, such is grain yield, reduces the usefulness of genotype means, over all environments, for selecting superior genotypes. AMMI model is a valuable statistical tool in identifying systemic variation contained in the interaction effect. Obtained data could be applied in maximizing yield potential in every environment based on both narrow and wide genotype adaptability, without the necessity of developing breeding programs for smaller targeted environments. Precise assortment of superior genotypes, with the assistance of AMMI model, leads to the better recommendation of newly bred hybrids, and thus increasing maize grain yield in a targeted environment. In this research genotype x environment interaction and yield stability of 36 maize hybrids of FAO 300-700 maturity group was investigating. The trial was set according to Randomized Complete Block Design (RCBD). Data were processed in order to obtain average estimates of grain yield, and yield stability was assessed by the method of AMMI analysis. The highest average grain yield was achieved in 2011 (11.62 t/ha), and the lowest in the most stressful and dry 2012 (6.90 t/ha). In the region Loznica L2 the highest average yield was noticed (13.81 t/ha), while at L7 (Sremska Mitrovica) average grain yield was the lowest (6.97 t/ha). Results of AMMI analysis gave precise recommendation for production of maize hybrids in certain environments, by determining winning areas of hybrids H20, H11 and H36. Medium early maturing and high yielding hybrids (H11 and H20) are therefore considered more favorable for production in environments with lower precipitation, while high yielding and more stable hybrids H21 and H35 are suitable for a wider range of environments. Hybrid H36 (FAO 700) showed its full potential at L2, and L3 which did not suffer from a lack of moisture. This hybrid also expressed its best potential in environments with favorable conditions
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