The purpose of this research is to focus on the solution of the resource sizing problem for the real production system. The resource sizing problem is tackled by usage of the mathematical makespan
...minimization method and comparative simulations of the two different production models. Only two production model simulations were realized due to specificities of the handled production system. Simulation results were presented, compared and discussed. This paper presents an approach which allows studying the heavy machine sizing problem realistically, through the use of simulation tools. The approach used would be of great help in making a decision on whether two new heavy machines should be introduced into an existing production system or not.
Višekomponentna seizmika pruža nam novi uvid u karakteristike ležišta. Primjena seizmike koja objedinjuje P i S valove (PS signal), temelji se na razlici refleksije tih valova u ležištu. Jedno od ...najvažnijih svojstava S valova je njihova relativna neosjetljivost na zasićenje, što nije slučaj kod P valova.
U polju Molve je snimljena i interpretirana 3D seizmika. Pouzdanost svakoga seizmičkog pojedinačnog atributa nije bila dovoljna da bi se mogli interpretirati zone s plinom, poroznost te zasićenje vodom. Razlog tomu je kompleksna litologija ležišta, predstavljena s čak 4 litofacijesa: litofacijesom IV (uglavnom retrogradno metamorfozirani gnajsevi; paleozojski i stariji), litofacijesom III (metakvarciti perma i trijasa), litofacijesom II (uglavnom dolomiti jurske i trijaske starosti) te litofacijesom I (miocenski vapnenci). To je razlog da seizmički atributi i parametri ležišta nisu mogli biti korelirani. Zato je kreirani novi složeni atribut (engl. „multi-atribut“) za svaki od četiri litofacijesa u ležištu. Takav atribut mogao se znatno lakše korelirati s petrofizikalnim varijablama. Na temelju Kalkomey-eva pristupa vjerojatnost da je takva korelacija lažna iznosi 0,15.
Nadalje, potvrđena je korelacija između atributa i poroznosti, posebno u litofacijesu III (sastavljenom od kvarcita, škriljavaca i grauvake). Zato je tu poroznost interpolirana upotrebom geostatističke metode kokriginga, tj. upotrebom sekundarne seizmičke varijable. Također, analiza složenoga atributa vodi do bolje vizualizacije dominantno vapnenačke litologije u litofacijesu II. Može se očekivati da će višekomponentna seizmika biti snimljena, kroz nekoliko godina, u većini važnih hrvatskih polja. Polje Molve jedno je od najvažnijih. Novi seizmički podatci svakako će poboljšati kvalitetu interpretiranih atributa te omogućiti uspostavljanje jasne korelacije između seizmičkih i petrofizikalnih podataka u svim litostratigrafskim jedinicama takvoga heterogenoga ležišta.
Keratoconus is a progressive, non-infl ammatory corneal ectasia characterized by thinning and weakening of the corneal
stroma which results in its’ protrusion. The onset is during puberty and ...progresses until the fourth decade of life. In
earlier stages, good visual acuity can be provided with spectacles. With progression, contact lenses are considered to be a
better therapy. Aim of this study was to determine if there is statistically signifi cant difference between best corrected visual
acuity (BCVA) obtained by spectacles and contact lenses in newly diagnosed keratoconus patients, as well as to determine
which type of contact lenses provide better BCVA in keratoconus patients. We conducted a 5-year retrospective
study of all 2891 patients attending our Contact Lens Department for the fi rst time, searching for patients newly diagnosed
with keratoconus. Data were obtained on gender, age, education level, treated eyes, corneal changes, keratoconus severity,
BCVA with spectacles, contact lenses and best fi tted contact lens type. All patients underwent standard ophthalmic exam,
refractometry and keratometry have been done, followed by a spectacles correction and lens fi tting. Wilcoxon signed rank
test was used for statistical analysis. Results showed that of all 2891 patients examined for the fi rst time, 137 patients
(4.74%) have been newly diagnosed with keratoconus, there was male bias (72.26%), mean age 27.7±9.9 years. Most patients
had high school education (51.11%), 3.70% had present corneal changes, 50.37% had mild keratoconus. Majority had
keratoconus on both eyes (36.3%) or keratoconus of right eye (26.67%). There was a statistically signifi cant difference
(p<0.001) between the BCVA obtained with contact lenses (0.82±0.21 Snellen chart) rather than spectacles (0.37±0.27
Snellen chart). The best corrected visual acuity was achieved with rigid gas permeable (RGP) lenses in majority of keratoconus
eyes (51.85%), with semi-gas permeable (SGP) lenses in 43.39%, in 4.23% with polymethyl methacrylate (PMMA)
lenses and with hard-soft gas permeable (GP) contact lenses in 0.53% of keratoconus eyes. We have showed that there is
a statistically signifi cant difference in BCVA achieved better with contact lenses than with spectacles. RGP lenses are most
frequently used in conservative treatment of keratoconus, but SGP lenses were also shown to be a good option that gives
equally satisfying fi nal visual acuity with subjective comfortable feeling of contact lens wear.
The experimental results of the transport properties: electrical resistivity, ρ, thermopower, S, and thermal conductivity, κ, of a polycrystalline sample of YbCu4.4, in the temperature range 2 to 300 ...K, are presented. In contrast to the divalent YbCu2 compound, YbCu4.4 has transport properties typical of an intermediate valence compound: relatively high electrical resistivity and large thermoelectric power. The electrical resistivity ρ(T) exhibits a typical Kondo lattice systems’ behaviour, with a room temperature value of ρr.t. ≈ 60 μΩ cm, while thermoelectric power S(T) is negative in the whole investigated temperature range. S(T) shows a distinct temperature dependence, which is attributed to the Kondo interaction. The room temperature, r.t., value of the thermal conductivity is κr.t. ≈ 20 W/mK. The pronounced maximum in κ(T) at low temperatures, which is frequently found in simple nonmagnetic and rather pure samples, is absent. The thermal conductivity decreases monotonically in a whole temperature range with a change in the slope around 50 K. The absence of a maximum in κ(T) could be related to the larger contribution of residual scattering processes and to the considerably weak coupling of electrons with phonons. The results are compared to the reported transport properties of similar Ce-Cu and Yb-Cu Kondo systems.
The aim of this paper was to show the potential of Salmonella enteritidis infection to eventually result in visual impairment. A case of salmonellosis in a 6-year-old boy, caused by intake of a cake ...made from eggs infected with Salmonella enteritidis, is presented. Prolonged duration of the disease was followed by complete remission of neurologic complications and persistent amaurosis with bilateral optic nerve atrophy. A severe form of Salmonella enterocolitis with neurologic involvement can lead to optic nerve lesion with consequential loss of vision.
A clinical trial was undertaken to evaluate the efficacy of hypertonic solution (5% NaCl) in patients who have bullous keratopathy (BK). The aim of the study was to define the stage of the disease ...and the thickness of cornea in micrometers, which would be the threshold for therapeutic approach. This was a prospective study on 70 eyes of 55 patients. Patients were divided in two groups at the beginning of the study.The first group (n=33 eyes) included patients with initial stage of BK: only stromal component of corneal oedema was present. The second group (n=37 eyes) included patients with advanced stage of BK: the epithelial component of the disease with bullae on the corneal surface had already developed. Visual acuity, central and peripheral thickness of cornea and morphology of the disease was recorded before therapy, 7 days and 4 weeks after administration of hypertonic solution. Our results shown that the efficacy of hypertonic solution correlates with the severity of clinical picture in patients with BK. When 5% NaCl hypertonic solution was applied in the early stage of the disease, when only stromal component of corneal oedema was presented, visual acuity and pachymetry readings were significantly improved. The threshold pachymerty measurement of corneal thickness justifying the application of hypertonic solution was 613–694 _m(in the central corneal area), and 633–728 _m(at corneal periphery). It seems reasonable to apply hypertonic solution to the patients who have BK and whose pachymetric values are below mentioned range. In terminal stages of BK, when superficial bullae (epithelial component) had already developed, treatment with NaCl was not effective and patients had to be submitted to penetrating keratoplasty.
