Thermal stress FEM analysis of rock with microwave energy

This paper presents a study of a thermal breakage process used to analyse the thermal stress and crack development that occur when rock is exposed to short-pulse microwave energy. A two-dimensional circular plate, containing two-phase minerals, was used in finite element simulation to calculate thermal stress for the purpose of better understanding thermal fracture behaviour in comminution. It is found that the thermal mismatch between a microwave-absorbing inclusion and a low-absorbing matrix mineral can generate large localized thermal stresses around the inclusion. Fracture initially occurs, not around the grain boundaries between the two minerals, but some distance away, as a result of thermal expansion stress on the matrix mineral. The results also indicate that though grain size is one of the factors causing cracks during heating of granular materials, it is not the only reason. The size and the thermal properties of the matrix mineral can also affect the results of thermal stresses

DIRECTIONS IN THE EVOLUTION OF CERVICAL L-SIL LESIONS

Molecular activities in the basic cytopathological substratum of the lesions on utherus cervicus, in case of HPV infection in form of squamous intraepithelial lesions of the low (L - SIL) and high (H - SIL) level, are defined by bathesda therminological system. More frequent, L - SIL changes include CIN I, coil atypia and condilomata lata and can be recognized by cellular abnormalities in the basal and parabasal layer with minor cellular structural changes , nuclei hyperhromasia with hromatin condensation, acantosis, paraceratosis with well differentiated cells and faster exfoliation. Women more prone to develop L-SIL are those older than 41, with III degree of vaginal secretion, with the colposcopic finding of aceto-white epithelium and Papa-Nicholaus test of III group. The control cervical, colposcopically controlled biopsy was resumed after four control medical check-ups done every three months after the L-SIL diagnosis. The results showed that lesions remained at the same stage (41,67%), whereas regression appeared in every third examinee (33,33%), slight progression in every eight examinee (12,50%), and significant progression in every twelfth examinee (8,33%).Our conclusion was that L-SIL lesions do not require the ablativ therapy a priory, and what is needed is a regular colpocytological check-up every three months and cervical biopsy, if necessary. Diagnosis of HPV infection certainly changes one’s attitude and requires loop diameter because of the additional diagnostic indications and final therapy

Značaj ribljeg brašna i drugih hraniva životinjskog porekla za proizvodnju smeša koncentrata

U radu je prikazan značaj ribljeg brašna kao i drugih hraniva životinjskog porekla za proizvodnju smeša koncentrata, kao i mogućnost njihove suspstitucije hranivima biljnog porekla u kombinaciji sa sintetičkim aminokiselinama, ili komercijalnim „zamenama“ ribljeg brašna. Riblje brašno je do sada najviše korišćeno hranivo životinjslog porekla. Zbog opasnosti od širenja bolesti Bovine spongiform encephalopathy – BSE, u Evropskoj uniji je regulativama 999/2001 i 1234/2003 zabranjena upotreba obrađenih animalnih proteina, u koje spadaju različite vrste mesno-koštanog brašna, za sve farmske životinje koje ulaze u lanac ishrane ljudi, izuzev ribljeg brašna za nepreživare. Kod nas je u skladu sa Zakonom o veterinarstvu iz 2005. uvedena obaveza za sve fabrike hrane za životinje da odvajaju linije u kojima se pripremaju koncentrati za preživare, ili da proizvodnju obavljaju na istoj liniji ali da se pri tome odreknu upotrebe hraniva životinjskog porekla. U skladu sa tim, vrši se stalni monitoring smeša za preživare. Zadnjih godina je korišćenje ribljeg brašna u ishrani nepreživara jako smanjeno zbog navedenih zakonskih ograničenja, sve lošije hranljive i upotrebne vrednosti (zdravstvene ispravnosti), problema falsifikovanja (dodavanja hraniva niže hranljive vrednosti: sojine sačme, kukuruznog glutena, brašna od perja pa čak i uree) kao i zbog visoke cene. Osim toga, dobro je poznato da riblje brašno prenosi svoj specifičan miris na proizvode pa se obavezno isključuje iz smeša pri kraju tova brojlera. Velike količine ribljeg brašna se i danas koriste pri proizvodnji peletirane hrane za pastrmke i druge karnivore ribe. Naime, ove vrste riba zahtevaju visok nivo proteina dobre biološke vrednosti u obrocima. Ranih 90-ih godina preporučivan odnos svarljivih sirovih proteina i svarljive energije u obrocima za pastrmke je bio 22-25 g/MJ. Nasuprot tome, u zadnjoj dekadi eksperimentalno je dokazana efikasnost obroka sa većim sadržajem masti (>20%) i kada je odnos proteina i energije uži. Međutim, u tom slučaju treba obezbediti odgovarajući nivo esencijalnih aminokiselina. Objašnjenje je u specifičnom metabolizmu riba. Krajnji proizvod metabolizma proteina u riba je amonijak, za šta je potrebno manje energije. Nasuprot tome, krajnji proizvod metabolizma energije u svinja je urea, čime se objašnjava uži odnos proteina i energije (oko 14 g/KJ). Zbog svega navedenog proizvođači teže da riblje brašno zamene (delimično ili potpuno) nekim drugim proteinskim hranivom (biljnog ili životinjskog porekla), pri čemu je jedan od glavnih ciljeva što niža cena proizvodnje. Do sada je najviše pažnje poklanjano proizvodima od soje, odnosno sojinoj sačmi. Ovo hranivo ima veliku biološku vrednost proteina ali i visok sadržaj različitih antinutritivnih materija. Nasuprot tome, efikasnijim se pokazao koncentrat proteina soje. To je hranivo koje se dobija uklanjanjem masti i rastvorljivih ugljenih hidrata. Eksperimentalno je utvrđena mogućnost delimične supstitucije ribljeg brašna suncokretovom sačmom, ali je glavni nedostatak ovog hraniva u velikoj količini nerastvorljivh ugljenih hidrata. Pored ovih hraniva, u eksperimentima su ispitivane sačme pamuka, kikirikija, uljane repice, brašno lupine, kukuruzni gluten, proteini krompira i dr. Međutim, nedostatak svih ovih hraniva je nizak nivo nekih esencijalnih aminokiselina kao i prisustvo antinutritivnih, štetnih i nesvarljivih materija. Jedno od potencijalnih proteinskih hraniva za ribe i domaće životinje je bakterijski protein. U pogledu brzine rasta i produkcije proteina, bakterije imaju prednost u odnosu na kvasce. Pored toga, bakterije sadrže i više proteina (do 80%), a aminokiselinski sastav je povoljniji i sličniji proteinima životinjskog porekla. Nedostatak je velika količina nukleinskih kiselina (do 18%) koje u sisara katabolišu do mokraćne kiseline. U zaključku se ističe da su troškovi ishrane ključni za rentabilnost proizvodnje u stočarstvu i nekim oblicima ribarske proizvodnje. Supstitucija ribljeg brašna u obrocima za domaće životinje i ribe je neophodnost zbog visoke cene ovog hraniva, varijabilnog kvaliteta i eventualnog falsifikovanja jeftinijim hranivima. Za sada, najveći značaj pokazuju proizvodi prerade soje a određenu perspektivu imaju i bakterijski proteini

THE DYEING PROCESS OF KNITTED FABRICS AT DIFFERENT TEMPERATURES USING ULTRASOUND

The dyeing of knitted fabrics made from 100 % cellulose using on-line procedure vinyl sulfonic reactive dye, with or without ultrasound energy, is carried out in this paper. The impact of temperature has been observed. The dye exhaustion is monitored using the method of absorption spectrophotometry, and the quality control of the coloration is monitored using color measurements. The acting of ultrasound on coloration consistency, as well as on some mechanical characteristics has also been examined. All examples of the ultrasound dyeing process show greater dye exhaustion in comparison to the conventional procedure. In addition, all the samples, which have been dyed with the ultrasound energy at 40°C, are significantly darker and have deeper color in comparison with the referent sample. The temperature has a great influence on kinetic energy of the dye molecules, and therefore on the diffusion processes in the dyeing system. The exhaustion chart indicates that when the temperature is lower the exhaustion degree drops. However, all the samples dyed with the ultrasound energy have bigger exhaustion. Besides that, ultrasound energy contributes to warming up the processing environment, so the additional warm up with the electricity is unnecessary, unlike the conventional way of dyeing. Since the reactive dyes chemically connect themselves with the cellulose substrate and in that way form covalent connection, the dyed fabrics have good washing consistency. Analysis results indicate that the consistencies are identical regardless the applied dyeing procedure. In other words, the dyeing method using the ultrasound energy produces the dyed fabric of the same quality. After analyzing the results of breaking force and elongation at break of knitted fabrics, it is noticeable that there is no degradation of previously mentioned knitted fabrics features (horizontally and vertically) during the ultrasound wave’s activity

DYEING OF KNITTED MICRO-VISCOSE IN THE PRESENCE OF ULTRASOUND WITH DIFFERENT FREQUENCIES

In dyeing process, the object is to transport or diffuse dyes and chemicals into the fibre. Various novel processes, including ultrasound, are being introduced and studied as more environmentally friendly alternatives. Encouraging results have been reported for the use of ultrasound energy in dyeing processes of micro-viscose. The recent studies revealed major ultrasound applications advances: savings of processing time, energy, chemicals, as well as environmental protection. Influence of various ultrasound frequencies (40, 200 and 400 kHz) on dyeing of micro-viscose knitted fabrics, by a reactive dye has been reported in this work. A method of reflection spectrophotometry has been employed to record reemission curves of the colored compounds. A software packet has been employed to calculate CIELab colored coordinates. Then, a comparison has been made with samples colored by conventional procedure according to CIELab76 and CMC (2:1) criteria. The use ultrasound in textile dyeing processing offers many potential advantages. The results prove better dye exhaustion by ultrasound and consequently the better fixing. The exhaustion for the bifunctional dye (containing two vinylsulphone groups) reaches 71.75 % without ultrasound, and 83.69 % with 400 kHz ultrasound. The 40 kHz, 150 W ultrasound causes a cavitation of higher intensity, compared to 200 and 400 kHz ultrasounds. In this particular case, destruction of cavitation bubbles is very intensive. That is why a large amount of cavitation energy is being transformed into a heat, yielding the additional bath heating. The ultrasounds with higher frequencies (200 and 400 kHz) cannot use such a strong power. The applied powering this case reaches 0.6 W. The cavitation bubbles are now smaller the cavitation disintegration is not so strong, and the energy loss is much smaller, i.e. a smaller amount of energy has been transformed into a heat. An ultrasound of an equal power, but of higher frequency contributes to the somewhat higher exhaustion and fixing. The ultrasound dyeing produces much obscured colours, compared the standard. The differences are evident and not negligible. The comparison of the samples treated ultrasound of different frequencies during dyeing revealed the higher coulours intensities with the increase of ultrasound frequencies of the equal power (200 and 400 kHz). However, the increase is not so expressed

Effects of Different Gas Compositions on the Color Estimations of MAP Packaged Pork Chops

AbstractThis study was conducted to observe effects of different gas compositions on color of pork chops packaged in modified atmospheres. Gaseous compositions used were: MAP1 (75% O2:25% CO2); MAP2 (70% O2:30%CO2) and MAP3 (80% O2:20% CO2). Sensory evaluations of meat color and chemical properties (acid number, peroxide value, aw, pH, TVB-N and TBARs), were carried on the 1st, 5th, 7th, 9th and 12th day of storage. The sensory evaluations of chop color in different MAP compositions are analyzed in relation to storage period, measured chemical properties and instrumental determination of meat color using linear and multivariate linear regression analysis

Morfološke i hemijske analize novih linija pastrnka (Pastinaca sativa L.) Instituta za povrtarstvo

In Serbia, a parsnip is often grown vegetable gardens and the gardens, grown for thickened roots that is used in spice who spravljanu delicious dishes. This paper presents the results of 12 new genotypes breeding - line parsnip Institute of Vegetable Crops Palanka. Their morphological and chemical characteristics were compared with the standard variety Panonski smooth. In the three-year period from 2009 - of 2012 were analyzed by the following morphological characteristics: the average root weight, the average weight of leaf, root collar diameter , the diameter of the root environment and the emergence of secondary roots. Is determined by the chemical analysis of the dry matter , the total minerals , total sugars , and water. The aim was to examine the quality of new lines parsnip than the standard variety Panonski smooth and select the new lines for the recognition of new varieties of parsnip Institute of Vegetable Crops.Pastrnak (Pastinaca sativa L.) pripada familiji Apiaceae, po svojim prehrambenim i lekovitim svojstvima spada u red najvrednijih povrtarskih kultura. U Srbiji pastrnak je često gajeno povrće po okućnicama i baštama,gaji se radi zadebljalog korena koji se koristi ko začin pri spravljanu ukusnih jela. Koristan je za zdravlje jer poboljšava apetit, pospešuje rad bubrega,deluje na smanjenje krvnog pritiska. U radu su prikazani rezultati ispitivanja 12 novo selekconisanih genotipova- linija pastrnka Instituta za povrtarstvo Palanka. Njihove morfološke i hemijske osobine upoređene su sa standardnom sortom Panonski glatki. U trogodišnjem periodu od 2009 – 2012.godine analizirane su sledeće morfološke osobine: prosečna masa korena, prosečna masa lista, prečnik vrata korena, prečnik sredine korena i pojava sekundarnih korenova. Hemijskom analizom određena je suva materija, ukupni minerali, ukupni šećeri i voda. Cilj je bio da se ispita kvalitet novo stvorenih linija pastrnka u odnosu na standarnu sortu Panonski glatki i odaberu nove linije za priznavanje novih sorti pastrnka Instituta za Povrtarstvo

The effect of corn grain micronization on diet digestibility and blood biochemical parameters in weaned Holstein calves

Aim of study: To evaluate corn grain micronization for calves fed a grower diet. Area of study: Padinska Skela – Belgrade, Serbia. Material and methods: Thirty weaned Holstein dairy calves (65–74 days of age) were randomly assigned to one of two treatments with growers containing micronized (MCG) or untreated corn grain (UCG). The experimental period lasted for 60 days. Main results: The values of total tract apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), and nonfiber carbohydrates (NFC) were higher for calves fed MCG versus those within the UCG treatment by 3.9% (p<0.05), 7.0% (p<0.01), 7.1% (p<0.01) and 7.5% (p<0.05), respectively, for the days 25–30 of the experimental period. In addition, the values of digestibility of OM, CP, and NFC were higher by 4.9% (p<0.05), 5.7% (p<0.05), and 6.0% (p<0.05), respectively, for the days 55–60 of the experimental period. The density of metabolizable energy, net energy for maintenance and gain in consumed dietary DM was higher (p<0.001) by 4.7, 5.5, and 7.2%, respectively for calves fed on the grower containing micronized corn grain (MCG), during the first digestibility period, and by 3.0, 3.6, and 4.6%, respectively, during the second digestibility period. Energy intake was lower (p<0.05) during the second digestibility period, for calves fed a diet with micronized corn. Blood urea N was affected (p<0.001) by dietary treatments. Lower values (10.2%) were observed for calves fed the grower containing MCG. Research highlights: The micronization of corn grain is a useful tool for optimizing weaned calf production due to the improvement in the digestibility and energy content of the ration. © 2023 CSIC