Stochastic simulations of dependent geological variables in sandstone reservoirs of Neogene age: A case study of Kloštar Field, Sava Depression

The research presented herein is the first attempt to perform geostatistical simulations on three geologic variables, porosity, thickness, and depth to reservoir, in the Croatian Pannonian basin. The data were collected from a reservoir of Lower Pontian age in Kloštar Field, located in the western part of the Sava Depression. All three variables were analyzed using sequential Gaussian simulations (SGS). Information regarding present-day depth, thickness, and locations of areas with higher porosity values were used to reconstruct paleo-depositional environments and the distribution of different lithotypes, ranging from medium-grained, to mostly clean sandstones and to pure, basin marls. Estimates of present-day thickness and depth can help to define areas of gross tectonic displacement and the role of major faults that have been mapped in the field. However, since mapping of the raw data (including porosities) does not allow the reconstruction of paleo-depositional environments, sequential indicator simulations (SIS) were applied as a secondary analytical tool. For this purpose, several cutoff values for thickness were defined in an effort to distinguish the orientation of depositional channels (main and transitional). This was accomplished by transforming porosities to indicator values (0 and 1) and by applying a non-linear “indicator kriging” technique as the “zero” map for obtaining numerous indicator realizations by SIS. In the SGS and the SIS approaches, the simulations encompassed 100 realizations. A representative realization was then selected using purely statistical criteria, i.e., two realizations were almost always chosen in accordance with the order of calculation. The 1st and 100th realizations were selected for each variable in the SGS and SIS and five “indicator kriging” maps were chosen for the thicknesses cutoffs

Development, Design and Flight Test Evaluation of Continuous Descent Approach Procedure in FIR Zagreb

As part of Local Conversion and Implementation Plan which is based on the EUROCONTROL Revised Convention the Republic of Croatia has undertaken to make a plan of implementing the Basic Continuous Descent Approach procedures. This paper addresses the issue of navigational path optimization for the A-319/320 commercial aircraft within the fleet of Croatia Airlines, during the approach part of flight, which has a positive effect on fuel consumption, greenhouse gas emission and area of surface affected by noise. The experiments were carried out in real conditions, using internal sensors onboard (Flight Data Recorder) and independent GPS system. Two types of approach were tested: Continuous Descent Approach (CDA) and Step Down Approach. The implementation of CDA procedures, just for the fleet of Airbus 320/319 aircraft of the Croatia Airlines results in approximate calculation in fuel saving which amounts to 1.5 x 106 kg annually (only on Zagreb airport). In this way, the productiveness of an air carrier, which is an integral part of the traffic process along with the airports and air traffic control, is directly increased, thus fulfilling the purpose of air traffic technology research. KEY WORDS: navigational procedures, continuous descent approach, air traffic, ecolog

Atomistic simulations of deformations in metals

Molekularna dinamika je metoda u kojoj se gibanje svakog pojedinog atoma ili molekule izračunava izravnom primjenom Newtonovih zakona (posebno 2.). Praktičan račun će uključiti veliki broj čestica, od nekoliko desetina do čak nekoliko milijuna. U tako složenim proračunima nužno je koristiti kompjutorsko simuliranje jer je kompleksni izračun nemoguće obaviti analitički za inženjerski relevantne sisteme. Makroskopske veličine se dobivaju statističkom obradom mikroskopskih putanja čestica. To je alat koji možemo koristiti za razumijevanje makroskopske fizike polazeći od atomskih fenomena. Ova metoda posljednjih godina doživljava veliki uzlet i ima široku primjenu za proračun termodinamičkih svojstava plinova, kapljevina i čvrste tvari. U ovom radu ćemo predstaviti simulaciju jednostavnog, ali iznimno važnog eksperimenta jednoosnog istezanja gredice aluminija korištenjem realnog međuatomskog potencijala pri čemu ćemo odrediti krivulju naprezanja-deformacija za sisteme pri različitim temperaturama te ih međusobno usporediti.Molecular dynamics is a method of calculating the motion of each individual atom or molecule utilizing Newton's laws of motion (in particular the 2nd law). The practical approach will include a large number of particles, from several dozens to even a few million. In such a complex calculation, the use of computer simulations is a must because the complex calculation cannot be done analytically for engineering relevant systems. Macroscopic physical quantities are going to be obtained by using statistical analysis of the microscopic particle trajectories. It is a tool for enhancing our understanding of the macroscopic physics starting from atomistic phenomena. This method has received a large boost within the last few years and has found application in the calculation of thermodynamic properties of gases, liquids, and solids. In this work, we shall present a simulation of a simple, but exceptional, uniaxial tensile test of an aluminum bar based on the realistic interatomic potential. We shall determine the stress-strain curve at different temperatures and compare them.

OVERVIEW PRODUCTION FEATURES OF JERSEY BREED COWS ON THE FARM "MALINOVAC"

Istraživanje je rađeno na farmi goveda „Malinovac“ izvan naselja Malinovac u općini Magadenovac. Za potrebe ovoga rada obuhvaćene su 22 krave Jersey pasmine od prve do treće laktacije. Nakon analize podataka utvrđena je prosječna dnevna proizvodnja za sve laktacije u iznosu od 16,9 kg. Utvrđena je prosječna količina mliječne masti od 4,9%, te proteina 4,1%. Prosječna vrijednost za ureu iznosila je 30,2 mg/100 ml. Pasmina Jersey iako manja konstitucijom i masom od ostalih pasmina mliječnih krava proizvodi gotovo podjednaku količinu mlijeka sa većom mliječnom masti. Pogodnija je za proizvodnju mliječnih proizvoda poput: sireva, vrhnja, jogurta i raznih sirnih namaza. Dokazana je superiornost krava Jersey pasmine po kvaliteti mlijeka i postotku mliječne masti. Zaključak istraživanja je da se i više nego isplati držati Jersey pasminu krava, jer je manji utrošak krmiva i vode u odnosu na ostale pasmine. Pri 10- 15% manjim obrokom od ostalih mliječnih krava njihovo mlijeko ima bolju kvalitetuResearch is taken on dairy farm "Malinovac" outside of place Malinovac in Magadenovac community. For the purposes of this research there were 22 Jersey breed cows included from the first till third lactation. After data analysis average daily production for all lactations is established in amount of 16.9 kg. Average amount of milk fat of 4.9 % and proteins of 4.1% has been determined. Average value of urea was 30.2 mg/100 ml. Jersey breed of cows although smaller in constitution and body weight than the other diary breeds, products almost equal amount of milk with higher percentage of milk fat. It is more suitable for production of milk products such as: cheese, cream, yoghurt and other cream cheese products. Superiority of Jersey breed cows has been proved in quality of milk and milk fat percentage. Conclusion of research is that Jersey breed cows are more than worth to have, because it costs less in food and water relating to other diary breeds. With 10-15 % smaller meal than the other diary breeds of cows their milk has better quality

Atomistic simulations of deformations in metals

Molekularna dinamika je metoda u kojoj se gibanje svakog pojedinog atoma ili molekule izračunava izravnom primjenom Newtonovih zakona (posebno 2.). Praktičan račun će uključiti veliki broj čestica, od nekoliko desetina do čak nekoliko milijuna. U tako složenim proračunima nužno je koristiti kompjutorsko simuliranje jer je kompleksni izračun nemoguće obaviti analitički za inženjerski relevantne sisteme. Makroskopske veličine se dobivaju statističkom obradom mikroskopskih putanja čestica. To je alat koji možemo koristiti za razumijevanje makroskopske fizike polazeći od atomskih fenomena. Ova metoda posljednjih godina doživljava veliki uzlet i ima široku primjenu za proračun termodinamičkih svojstava plinova, kapljevina i čvrste tvari. U ovom radu ćemo predstaviti simulaciju jednostavnog, ali iznimno važnog eksperimenta jednoosnog istezanja gredice aluminija korištenjem realnog međuatomskog potencijala pri čemu ćemo odrediti krivulju naprezanja-deformacija za sisteme pri različitim temperaturama te ih međusobno usporediti.Molecular dynamics is a method of calculating the motion of each individual atom or molecule utilizing Newton's laws of motion (in particular the 2nd law). The practical approach will include a large number of particles, from several dozens to even a few million. In such a complex calculation, the use of computer simulations is a must because the complex calculation cannot be done analytically for engineering relevant systems. Macroscopic physical quantities are going to be obtained by using statistical analysis of the microscopic particle trajectories. It is a tool for enhancing our understanding of the macroscopic physics starting from atomistic phenomena. This method has received a large boost within the last few years and has found application in the calculation of thermodynamic properties of gases, liquids, and solids. In this work, we shall present a simulation of a simple, but exceptional, uniaxial tensile test of an aluminum bar based on the realistic interatomic potential. We shall determine the stress-strain curve at different temperatures and compare them.