Rheological Modeling of Yarn Elongation

Na temelju eksperimentalnih podataka dobivenih za istezanje pređe u standardnim uvjetima ispitivanja, kombinacijom poznatih elementarnih reoloških modela, postavljenih reoloških modela istezanja pređe, izvedene su i riješene odgovarajuće diferencijalne jednadžbe za ispitivane pređe. Time je dobivena ovisnost između jedinične sile (naprezanja) i relativnog istezanja. Modeli su postavljeni za tri vrste pređe: vunena pređa finoće 21 tex prosječnog broja uvoja 1646 m-1 uz koeficijent varijacije 6,78%, pamučna pređa finoće 10 tex prosječnog broja uvoja 1020 m-1 uz koeficijent varijacije 16,7 i pređa od mješavine vuna/PES 76/24% finoće 12,5 tex prosječnog broja uvoja 1080 m-1.Based on the experimental data obtained for yarn elongation in standard test conditions, by combination of known elementary rheological models and established rheological models of yarn elongation, differential equations for the tested yarns were derived and solved. Thereby, the dependence between unit force (stress) and relative elongation was obtained. The models were established for three types of yarn: wool yarn with a count of 21 tex of anaverage twist level of 1,646 m-1 with a variation coefficient of 6.78%, cotton yarn with a count of 10 tex of an average twist level of 1,020 m2 with a variation coefficient of 16.7% and wool/PES blend yarn 76/24% with a count of 12.5 tex and an average twist level of 1,080 min-1

Effect of variable frequency electromagnetic field on deposit formation in installations with geothermal water in Sijarinjska spa (Serbia)

In this paper we have examined the effect of variable frequency electromagnetic field generated with a homemade device on deposit formation in installations with geothermal water from Sijarinjska Spa. The frequency alteration of the electromagnetic field in time was made by means of the sinusoidal and saw-tooth function. In laboratory conditions, with the flow of geothermal water at 0.015 l/s and temperature of 60 °C for 6 hours through a zig-zag glass pipe, a multiple decrease of total deposit has been achieved. By applying the saw-tooth and sinusoidal function, the decrease in contents of calcium and deposit has been achieved by 8 and 6 times, respectively. A device was also used on geothermal water installation in Sijarinjska Spa (Serbia), with the water flow through a 1'' diameter non-magnetic prochrome pipe at 0.15 l/s and temperature of 75 °C in a ten-day period. A significant decrease in total deposit and calcium in the deposit has also been achieved

Pilot plant for exploitation of geothermal waters

In Sijarinska spa, there are some 15 mineral and thermomineral springs, that are already being used for therapeutic purposes. For the exploitation of heat energy boring B-4 is very interesting. It is a boring of a closed type, with the water temperature of about 78°C and a flow rate of about 33 l/s. Waters with the flow rate of about 6 l/s are currently used for heating of the Gejzer hotel, and waters of the flow rate of about 0,121 l/s for the pilot drying plant. The paper presents this pilot plant.

Physicochemical and geochemical characterization of geothermal waters sedimentation tendency at Sijarinska spa and Vranjska spa (Serbia)

A comprehensive analysis of physicochemical parameters in geothermal waters from the sites in Sijarinska spa (drill hole B-4) and Vranjska spa (drill hole VG-2) in order to investigate their tendency to form deposits in the pipe installation is presented. Drill holes B-4/VG-2 posses utilization capacity of 30/27 L s-1 with water temperatures 75/90 oC. VG-2 water does not show any tendency to (or shows very small) sedimentation compared to the B4 water. The behaviour of the geothermal water from the B-4 hole was examined in real condition in Sijarinska spa, by letting it flow through the pipe installation. The results of geochemical analysis of water B-4 show that aragonite is the predominant mineral in the sediment (98 %) with lesser amount of calcite, vaterite and anhydrite. [Projekat Ministarstva nauke Republike Srbije, br. TR 33034

Direct Formation of Burkeite in the Geothermal Waters at Vranjska Banja, Serbia

There are no available data about direct burkeite formation on the geothermal waters pipelines in Europe. Data about accompanying minerals of burkeite are also scarce. This mineral has been found in the scale on pipelines of VG-2 and VG-3 boreholes at Vranjska Banja, Serbia. Geothermal waters from these boreholes have temperatures in the range of 103 and 105 °C which classifies them to the warmest waters in the continental Europe. Based on physicochemical and geochemical data, VG-2 and VG-3 geothermal waters can be classified as Na–Alk–SO4Cl type of waters. According to their temperatures, total hardness and pH values, these waters belong to hyperthermal, very soft and moderately alkaline. Calculated LSI (0.4 and 1.7) and RSI (6.5 and 4.8) values indicate their scale formation tendency. Results of the spectrometric scale examination from the pipe deposits provide a clear qualitative and quantitative burkeite characterization with its accompanying minerals. FTIR analysis points to the presence of carbonate (1766, 1458, 877 and 705 cm−1) and sulfate bands (1139, 1116 and 617 cm−1). Apart from the qualitative analysis, XRD also shows the burkeite mass part in the scale. VG-2 geothermal water contains about 50% of burkeite, which is associated with trona mineral (40%) and smaller amount of halite of about 10%. Burkeite is a dominant phase (> 60%) in VG-3 water, with the presence of a significant halite quantity (> 35%) and a minor calcite quantity (2%). © 2019, International Association for Mathematical Geosciences

Multifocal Abrikossoff's granular cell tumor of the oesophagus: Case report

INTRODUCTION Granular cell tumors, relatively uncommon soft tissue tumors, have been a matter of debate among pathologists regarding histogenesis for a long time. Less common locations are in the aerodigestive tract including the oesophagus. CASE OUTLINE We have recently treated a rare case, a 37-year old male, who was admitted due to dysphagia and a painful swallow with occasional pharyngo-nasal regurgitation followed with a mild loss of weight. Standard clinical examination including X-ray chest, ECG and laboratory tests did not show pathological findings. Barium contrast oesophagography demonstrated multiple ovoid defects in the wall of the oesophagus. CT scan of the chest confirmed luminal narrowing owing to the tumor of the upper oesophagus. Upper endoscopy showed unusual multifocal nodular lesions alongside the oesophageal axis covered by smooth mucosa. A primary biopsy specimen taken from the largest nodules confirmed an unusual pathological finding of the granular cell tumor. Subtotal, transpleural oesophagectomy was performed and reconstruction was derived by long colon segment interposition through the posterior mediastinum. The postoperative course was uneventful. The operative specimen consisted of four ovoid tumors alongside the oesophagus (the greatest diameter 0.5-1.8, average 1.25). All verified tumors histologicaly consisted of a spindle-shaped or polygonal cells containing small and large eosinophilic granules and central nuclei. Most tumor cells showed strongly positive immunohistochemical staining for S-100 protein. These tumor cells were partially positive for p-53 and Ki-67. No lymph node metastases were detected histologically. CONCLUSION Multifocal granular cell tumor of the oesophagus is an unusual finding with low incidence, and rarely caused symptoms. Pathological features and multiplicity of such tumors emphasized malignant predisposition requiring surgical resection of the oesophagus

Pomegranate Peel Extract Attenuates Isoprenaline-Induced Takotsubo-like Myocardial Injury in Rats

Takotsubo syndrome (TTS) is an acute heart failure syndrome characterised by catecholamine-induced oxidative tissue damage. Punica granatum, a fruit-bearing tree, is known to have high polyphenolic content and has been proven to be a potent antioxidant. This study aimed to investigate the effects of pomegranate peel extract (PoPEx) pre-treatment on isoprenaline-induced takotsubo-like myocardial injury in rats. Male Wistar rats were randomised into four groups. Animals in the PoPEx(P) and PoPEx + isoprenaline group (P + I) were pre-treated for 7 days with 100 mg/kg/day of PoPEx. On the sixth and the seventh day, TTS-like syndrome was induced in rats from the isoprenaline(I) and P + I groups by administering 85 mg/kg/day of isoprenaline. PoPEx pre-treatment led to the elevation of superoxide dismutase and catalase (p p p 2O2, O2− (p 2− (p < 0.001), in the P + I group, when compared to the I group. In addition, a significant reduction in the levels of cardiac damage markers, as well as a reduction in the extent of cardiac damage, was found. In conclusion, PoPEx pre-treatment significantly attenuated the isoprenaline-induced myocardial damage, primarily via the preservation of endogenous antioxidant capacity in the rat model of takotsubo-like cardiomyopathy