Utjecaj tehnoloških parametra na pojavu zaostalih naprezanja u željeznim odljevcima

The paper establishes the present day state of knowledge on parameters influencing residual stresses in iron castings, based on writings on this subject. Furthermore, testing examined the influence of parameters, such as mold humidity, mold stiffness; pouring temperature and carbon equivalent (CE) on residual stresses. Tests have been carried out on standard grating test piece made of grey cast iron, poured in sand molds. The obtained measurements have been drawn in diagrams and the influence of each single parameter has been evaluated.U radu je proučavanjem literature utvrđeno sadašnje stanje spoznaje o utjecajnim parametrima na zaostala naprezanja u odljevcima. Zatim je eksperimentalno ispitan utjecaj vlažnosti kalupa, tvrdoće kalupa, temperature ulijevanja, ugljikova ekvivalenta na zaostala naprezanja. Ispitivanja su provedena na standardnoj rešetkastoj probi od sivog lijeva koja je lijevana u pješčane kalupe. Na temelju mjernih rezultata nacrtani su dijagrami i analiziran je utjecaj svakog pojedinog parametra

UČINAK SELEKCIJE SNIŽENJA STABLJIKE NA UROD I KOMPONENTE URODA ZRNA JEČMA

This investigation deals with the effects of selection for short stem in population lines of the F4 generation derived from the barley cross between Timura x Osk. 4.208´2-84 developed by the single seed descent and pedigree method. Direct genetic gain from reducing the stem length was found to be 10.22 % at dense planting (400 kernels/m2) and 11.47 % at wide-spaced planting (100 kernels/m2). It was found that stem length had relatively high heritability (0.643 and 0.735). Large negative effects of reducing the stem length at wide-spaced and dense planting were estimated for the grain yield per plant, grain yield per plot and number of fertile tillers. Less pronounced negative effects were found for the grain weight per spike and grain number per spike. Phenotypic and genotypic correlations between stem length and other traits were mostly significant and positive with higher values at dense planting. Selection for a short stem length was efficient for the improvement of this trait. However, unfavorable correlations have significantly affected undesired expression of other traits, especially grain yield per plant, grain yield per plot and number of fertile tillers. Any further decrease of plant height should be accompanied by the appropriate selection for other traits, especially grain yield per plant, mass of one grain and harvest index.U radu su istraženi učinci selekcije na kraću stabljiku kod ječma u populaciji linija F4 generacije izvedene iz kombinacije križanja Timura x Osk.4.208´2-84 pomoću metode potomstva sjemenke po biljci (SSD) i pedigree metode. Ostvarena izravna genetska dobit sniženja stabljike bila je 10,22 % u gustoj sjetvi (400 zrna/m2 ) i 11,47 % u rijetkoj sjetvi (100 zrna/m2 ). Utvrđeno je da je dužina stabljike svojstvo relativno visokog heritabiliteta (0,643 i 0,735). Jaki negativni učinci sniženja dužine stabljike u rijetkoj i gustoj sjetvi procijenjeni su za urod zrna po biljci, urod zrna po parceli i broj plodnih vlati. Manje naglašeni negativni učinci utvrđeni su za masu zrna po klasu i broj zrna po klasu. Fenotipske i genotipske korelacije između dužine stabljike i drugih svojstava bile su uglavnom značajne i pozitivne s višim vrijednostima u gustoj sjetvi. Selekcija na skraćenje stabljike bila je učinkovita za poboljšanje toga svojstva. Međutim, nepovoljne korelacije značajno su utjecale na neželjenu ekspresiju drugih svojstava, naročito na urod zrna po biljci, urod zrna po parceli i broj plodnih vlati. Daljnje snižavanje visine stabljike trebalo bi biti praćeno i odgovarajućom selekcijom na druga svojstva, posebno urod zrna po biljci, masu zrna i žetveni indeks

Integrirani informacijski sustav tvornice aluminija - ISAL

The organization of aluminum production process is complex and multifaceted task, which necessitates handling and control of huge amount of information (composition of casting, content of the pots, energy consumption, electric parameters, chemical composition analysis, etc.). The need to ensure stable access to all the relevant data necessitated development of Integrated informational system for logistic support for production of anodes, electrolysis and aluminum smelter. This paper describes basic design and structure of this Integrated Informational System, developed for the needs of Aluminum Smelter Company “Aluminij d. d.” Mostar.Upravljanje složenim procesom proizvodnje aluminija zahtjeva raspolaganje velikom količinom podataka (sastav taline, sadržaj lonaca, utrošak energije, električni parametri, analize kemijskog sastava i dr.). Potreba za brzim pristupom podacima zahtijevala je izgradnju integralnog informacijskog sustava za logističku podršku poslovima izrade anoda, elektrolize i proizvodnje aluminija. U radu je opisana osnovna struktura Integralnog informacijskog sustava razvijenog za poduzeće Aluminij d. d. Mostar

Residual stresses in castings produced by press die casting technology

The influence of technological parameters on residual stresses in pressure die castings is analysed in this paper. In order for the residual stresses to be as low as possible the optimization of technological parameters is necessary. The centrally composed plan of experiment 24cs is used in the investigation. Technologically influencing parameters are changed according to the mentioned plan of experiment and they are: temperature of pouring, rate of die cavity filling with the melt, post pressure in already filled die and the casting cooling time along with the pouring system

High density SNP and DArT-based genetic linkage maps of two closely related oil palm populations

Oil palm (Elaeis guineensis Jacq.) is an outbreeding perennial tree crop with long breeding cycles, typically 12 years. Molecular marker technologies can greatly improve the breeding efficiency of oil palm. This study reports the first use of the DArTseq platform to genotype two closely related self-pollinated oil palm populations, namely AA0768 and AA0769 with 48 and 58 progeny respectively. Genetic maps were constructed using the DArT and SNP markers generated in combination with anchor SSR markers. Both maps consisted of 16 major independent linkage groups (2n = 2× = 32) with 1399 and 1466 mapped markers for the AA0768 and AA0769 populations, respectively, including the morphological trait “shell-thickness” (Sh). The map lengths were 1873.7 and 1720.6 cM with an average marker density of 1.34 and 1.17 cM, respectively. The integrated map was 1803.1 cM long with 2066 mapped markers and average marker density of 0.87 cM. A total of 82% of the DArTseq marker sequence tags identified a single site in the published genome sequence, suggesting preferential targeting of gene-rich regions by DArTseq markers. Map integration of higher density focused around the Sh region identified closely linked markers to the Sh, with D.15322 marker 0.24 cM away from the morphological trait and 5071 bp from the transcriptional start of the published SHELL gene. Identification of the Sh marker demonstrates the robustness of using the DArTseq platform to generate high density genetic maps of oil palm with good genome coverage. Both genetic maps and integrated maps will be useful for quantitative trait loci analysis of important yield traits as well as potentially assisting the anchoring of genetic maps to genomic sequences

Interpretation of GEI effect analysis for some agronomic and quality traits in ten winter wheat ( Triticum aestivum L.) cultivars

Ten winter wheat ( Triticum aestivum L.) cultivars were tested in randomized complete block design (RCBD) trials at one location (Osijek) for several agronomic and quality traits through six growing seasons (1996/97–2001/02). Data were employed to develop modeling strategy for exploring genotype by environment interaction (GEI) by using models based on information on genotypic and environmental variables. The relative size, hence importance of the GEI compared to main effects of genotypes and environments was estimated for all effects from simple additive model (genotypes, environments and residuals, last including both GEI and experimental error) while the AMMI2 model was used as a basis for comparison of the GEI patterns. The final step in modeling strategy was fitting factorial regression models to all analyzed traits using available genotypic and environmental covariates, until the best fit solution was found for each analyzed trait.Comparing the relative sizes of genotypic and GEI effects, the last one was sizeable smaller, for all traits except grain yield (GY), thousand-kernel weight (TKW), and Hagberg falling number (HFN). Fitting of genotypic and environmental covariates resulted in various solutions for different traits, most frequently employing single genotypic covariate — Glu-A1.Regardless of their relatively small size, the GEI effects in wheat quality traits can offer a better insight into fluctuations of varietal quality over a range of environmental conditions, as they can be successfully modeled using various genotypic and environmental covariates. The advantage of described approach is attainable in virtually any breeding program, because during the implementation of the program breeders routinely score for a number of genotypic and environmental variables

Comparison of different planting methods in relation to grain yield of wheat

The objective of this paper was to evaluate the adequacy of different methods of planting in small plots and compared with the grain yield rank of wheat genotypes in large plots under different planting densities. Significant differences were found among cultivars, same cultivars under different planting densities, years of testing and planting densities. The estimated values of heritability in narrow sense for grain yield were high and varied from 68 to 99%, depending on the method of planting and planting density. Comparison of correlation among cultivar’s rank between Method 1 (planting with drilling machine) and other Methods (manual planting) revealed that these relationships were dependant upon the year of testing and varied from low to high, positive or negative and from significant to non-significant. The highest correlation was found between Method 1 and Method 3 (20 kernels/hill) in both years of testing. If we wish to test a larger number of genotypes from gene bank collections or advanced lines in early phase of breeding program for grain yield on small plots we can recommend the use of hill plots with planting density as close as possible to those in large plots

GENETIC DIVERSITY OF WHEAT CULTIVARS ESTIMATED BY SSR MARKERS

Presence and utilization of the genetic variability in the breeding programmes is prerequisite for their successfulness. Important factor for crop improvement is knowledge about the genetic diversity which providing a basis for the precise selection of parental combinations. Since beginning of 20th century, generation of wheat breeders and scientists in Croatia developed numerous advanced and successful wheat cultivars. Previous researches aimed to genetic diversity evaluation in Croatia were conducted by means of morphological traits, pedigree data (coefficients of parentage), proteins (glutenins and gliadins) and RAPD DNA markers. DNA markers detect directly variation of DNA sequence for particular loci and they are not under influence of environment, epistatic and pleiotropic effects. Microsatellite markers (Simple Sequence Repeats; SSRs), as highly polymorphic, informative and codominant DNA marker system, have been extensively used for genetic diversity studies on wheat world wide. A set of 98 wheat cultivars released in Croatia during the period 1905-2007, and 24 foreign cultivar (included because of their ancestral significance or as standards), were screened by 45 microsatellite markers, covering all three wheat genomes. The objectives of this study were to evaluate the microsatellites-based genetic diversity with emphasize on cultivars created at the Agricultural Institute Osijek, as well as to investigate SSR application for selection of genetically the most distant parental pairs. Preliminary data obtained by means of SSR markers showed a satisfactory level of genetic diversity and usefulness of microsatellites for parental selection

Influence of gluten proteins on technological properties of Croatian wheat cultivars

The gluten proteins of 15 winter wheat cultivars grown in eastern Croatia were studied for their contribution to the bread-making quality. Composition of high-molecular-weight glutenin subunits (HMW-GS) was analyzed by SDS-PAGE, while the quantity of gluten proteins was determined by combined extraction/RP-HPLC procedure. The results of the linear correlation analysis carried out on the particular gluten proteins and technological properties showed that the amount of total gluten content highly correlates with protein content. Among gluten proteins, the glutenins showed higher correlation with protein content, with pronounced influence of HMW-GS, than gliadins. Wet gluten content was significantly correlated to total gliadin quantity. Gluten index as gluten quality parameter was positively influenced by total glutenins and low-molecular-weight glutenin subunits (LMW-GS), and negatively, by the ratios of gliadin to glutenin (Gli/Glu), whereas the amount of gliadins was not important. Dough development time was strongly correlated with total gluten content, total glutenins and the Gli/Glu ratio. Dough mixing resistance was strongly affected by total glutenin content with pronounced influence of HMW-GS. Degree of dough softening is mainly negative influenced by total glutenins and ratio of Gli/Glu. Farinograph quality number as flour quality index was highly positively correlated with total glutenins, with emphasized influence of HMW-GS. The Gli/Glu ratio had the highest influence on dough maximum resistance. Dough extensibility showed moderate correlation with total gliadins. The results of the linear correlation indicated that loaves volumes were significantly influenced by total gluten proteins, HMW-GS and LMW-GS