Ultrazvučna karakterizacija cementnih kompozita tijekom hidratacije

Ultrasonic measurements used to monitor the hydration of cement based materials are becoming an important tool in the quality assurance in production. Also, using these methods can be cost benefit for the construction companies because they can provide information about evolution of material properties in real time. In this paper ultrasonic testing is used to characterize a hydration process of cement paste. A technique is based on the system for measuring the ultrasonic pulse velocity (UPV). To obtain more information about wave propagation characteristics the technique of acoustic emission (AE) is also used. Entire waveform of the signal is recorded. AE parameters are extracted from the signal and used to characterize different processes in cement paste during hydration. An analysis is performed on cement pastes made with different water-cement ratios. Ultrasonic wave parameters are compared to the initial and final setting time using the Vicat needle test and compressive strength development.Korištenje ultrazvučnih mjerenja za praćenje hidratacije materijala na bazi cementa postaje važan alat osiguranja kvalitete u proizvodnji. Također, korištenje tih metoda može biti ekonomski isplativo za izvođačke tvrtke jer omogućavaju trenutno dobivanje informacija o razvoju svojstava materijala. U ovom radu ispitivanje ultrazvukom je primijenjeno za karakterizaciju procesa hidratacije cementne paste. Metoda mjerenja temeljena je na sustavu za mjerenje brzine ultrazvučnog impulsa (UPV). Kako bi se dobilo više informacija o svojstvima širenja valova korištena je i metoda akustične emisije (AE). Cijeli valni zapis je sniman te su iz signala izračunati parametri akustične emisije koji su korišteni za karakterizaciju različitih procesa u cementnoj pasti tijekom hidratacije. Analiza je provedena na cementnim pastama izrađenim s različitim vodo-cementnim omjerima. Parametri ultrazvučnih valova uspoređeni su s početkom i krajem vezanja dobivenim Vicatovom iglom i razvojem tlačne čvrstoće

Ultrazvučna karakterizacija cementnih kompozita tijekom hidratacije

Ultrasonic measurements used to monitor the hydration of cement based materials are becoming an important tool in the quality assurance in production. Also, using these methods can be cost benefit for the construction companies because they can provide information about evolution of material properties in real time. In this paper ultrasonic testing is used to characterize a hydration process of cement paste. A technique is based on the system for measuring the ultrasonic pulse velocity (UPV). To obtain more information about wave propagation characteristics the technique of acoustic emission (AE) is also used. Entire waveform of the signal is recorded. AE parameters are extracted from the signal and used to characterize different processes in cement paste during hydration. An analysis is performed on cement pastes made with different water-cement ratios. Ultrasonic wave parameters are compared to the initial and final setting time using the Vicat needle test and compressive strength development.Korištenje ultrazvučnih mjerenja za praćenje hidratacije materijala na bazi cementa postaje važan alat osiguranja kvalitete u proizvodnji. Također, korištenje tih metoda može biti ekonomski isplativo za izvođačke tvrtke jer omogućavaju trenutno dobivanje informacija o razvoju svojstava materijala. U ovom radu ispitivanje ultrazvukom je primijenjeno za karakterizaciju procesa hidratacije cementne paste. Metoda mjerenja temeljena je na sustavu za mjerenje brzine ultrazvučnog impulsa (UPV). Kako bi se dobilo više informacija o svojstvima širenja valova korištena je i metoda akustične emisije (AE). Cijeli valni zapis je sniman te su iz signala izračunati parametri akustične emisije koji su korišteni za karakterizaciju različitih procesa u cementnoj pasti tijekom hidratacije. Analiza je provedena na cementnim pastama izrađenim s različitim vodo-cementnim omjerima. Parametri ultrazvučnih valova uspoređeni su s početkom i krajem vezanja dobivenim Vicatovom iglom i razvojem tlačne čvrstoće

Trend analize žetvenih površina, proizvodnje i prinosa lucerke u Vojvodini

Vojvodina Province is a major alfalfa producer in Serbia with approximately 35.7% of total area and total production share of approximately 43.1%. In this paper, the data on area, production and yield of alfalfa observations from 1947 to 2018 and their variation and trends are analysed. The data indicate wide differences in the harvested area, total production and yield of alfalfa. The analysis of data indicates that harvested area and total production of alfalfa have declined over the past decades. Yield trend shows strong yield increase during 1950-1980 followed by periods of declined growth rates to 1990. After 1990s, dry matter yield has been stagnant. However, the increase, decrease and stagnation in yield are not strictly linear.Vojvodina je glavni proizvođač lucerke u Srbiji sa oko 35,7% ukupne površine i udelom proizvodnje od 43,1%. U radu analiziramo podatke o površini, ukupnoj proizvodnji i prinosu lucerke u periodu od 1947. do 2018. godine i njihovim varijacijama i trendovima. Takođe, procenjujemo da li je rast prinosa zastao tokom poslednjih godina. Podaci ukazuju na velike razlike u žetvenoj površini, ukupnoj proizvodnji i prinosu lucerke. Analiza podataka pokazuje da su žetvene površine i ukupna proizvodnja lucerke opali tokom poslednjih decenija. Trend prinosa pokazuje snažan porast prinosa od 1950. do 1980. godine, a zatim sledi period opadanja prinosa do 1990. godine. Nakon 1990. godine, prinos suve materije lucerke stagnira. Međutim, porast, smanjenje i stagnacija u prinosu nisu strogo linearni

Forage yield and protein content of different field pea cultivars and oat mixtures grown as winter crops

Monoculture and intensive use of mechanization and inorganic chemicals are leading to degradation and erosion of our soils and agro-ecosystems. At the same time, the production of animal feeds that are rich in protein is constantly decreasing in many European countries. Modest cultivation needs, favorable content of nutrients, and beneficial effect on the environment, make field pea and oat mixtures promising crops to tackle these issues. In three growing seasons and without irrigation or fertilisation, we have examined two basic field pea cultivars (Kosmaj, OS Adam) and one leafless cultivar (OS Letin) intercropped with oat (NS Jadar), with seeding rates, field pea: oat - 100:10%; 100:20% Results have shown that basic type cultivars have better overall development and higher yields compared to leafless cultivar, whether grown as single crops or in the mixture. Basic cultivars (OS Adam, Kosmaj) achieved higher protein content, compared to cultivar Letin, 163.9 g kg(-1), 153.3 g kg(-1), 136 g kg(-1), respectively. Yields were higher in 100:20% mixtures, compared to 100:10% mixtures and single grown crops, and we conclude that intercropping these species is superior to cultivating them separately. Protein content wasn't significantly different between two seeding rates, thus seed rates shouldn't be lower than 100:20%

Čimbenici rizika za infekciju kirurškog mjesta u operacijama karcinoma grkljana

Surgical site infection (SSI) is a significant factor of morbidity and mortality in patients surgically treated for laryngeal carcinoma. The aim of this prospective study in 277 patients was to determine the incidence of SSI in patients surgically treated for laryngeal squamous cell carcinoma and to identify risk factors for development of SSI. Patients with previous chemotherapy and/or radiotherapy were excluded. All patients had tracheostomy postoperatively and received antibiotic prophylaxis with cephalosporin, aminoglycoside and metronidazole. The overall incidence of SSIs in our cohort was 6.5% (18 patients): 4 (22.22%) patients with superficial infections, 11 (61.11%) with deep infections and 3 (16.66%) with organ-space infections. The remaining infections included pneumonia (1 case) and Clostridium difficile colitis (2 cases). The median hospital stay in patients having developed SSIs was longer than in those without SSIs (33.5 vs. 16 days, p<0.001). By using univariate analysis American Society of Anesthesiologists score ≥3, duration of surgery longer than 120 minutes and National Nosocomial Infections Surveillance risk index ≥1 were found to be significantly associated with the occurrence of SSI. Age, sex, body mass index, history of smoking, underlying diabetes and preoperative length of stay were found not to be associated with SSI. The most frequently isolated microorganism was Klebsiella spp.Infekcije kirurškog mjesta (IK M) predstavljaju značajan čimbenik za obolijevanje i smrtnost u bolesnika operiranih zbog karcinoma grkljana. Cilj ove prospektivne studije koja je obuhvatila 227 bolesnika bio je odrediti incidenciju IK M te utvrditi čimbenike rizika za njezin nastanak. Studija je isključila bolesnike s prethodnom radio- i/ili kemoterapijom. Svi su bolesnici imali poslijeoperacijsku traheostomu, a primali su antibiotičku profilaksu koja je sadržavala cefalosporin, aminoglikozid i metronidazol. Uočeno je da je srednja incidencija IK M 6,5% (18 bolesnika), uz 4 (22,22%) slučaja s površinskom incizijskom infekcijom, 11 (66,22%) s dubokom incizijskom infekcijom i 3 (16,66%) s infekcijom organa ili prostora. Ostale infekcije su bile upala pluća (1 bolesnik) i kolitis prouzročen bakterijom Clostridium difficile (2 bolesnika). Srednje trajanje bolničkog liječenja u bolesnika kod kojih se razvila IK M bilo je dulje od onih bez IK M (33,5 dana prema 16 dana; p<0,001). Koristeći univarijatnu analizu nađeno je da su ASA skor ≥3 Američke udruge anesteziologa, kirurška intervencija dulja od 120 minuta i NNI S (Nacionalno praćenje nozokomijalnih infekcija) indeks rizika ≥1 značajno udruženi s pojavom IK M. Godine, spol, tjelesna masa, pušenje, dijabetes, duljina prijeoperacijskog boravka u bolnici nisu povezani s IK M. Najčešće izolirani mikroorganizam je bila Klebsiella spp

Supplementary data for article: Božić, B.; Korać, J.; Stanković, D. M.; Stanić, M.; Popović-Bijelić, A.; Bogdanović Pristov, J.; Spasojević, I.; Bajčetić, M. Mechanisms of Redox Interactions of Bilirubin with Copper and the Effects of Penicillamine. Chemico-Biological Interactions 2017, 278, 129–134. https://doi.org/10.1016/j.cbi.2017.10.022

Supplementary material for: [https://doi.org/10.1016/j.cbi.2017.10.022]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2570]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3105

Inverted Sinonasal Papilloma – A Report of 31 Cases and Review of the Literature

Inverted papilloma is an epithelial neoplasm of the lateral nasal wall and adjacent sinuses characterized by a marked propensity for recurrence and a significant association with carcinoma In this retrospective study we present 31 cases treated by our departments between 1982 and 1999. The aim was to compare our results to those of other authors especially regarding surgical management. The male to female ratio of these patients was 2:1 and most patients were in the 6th and 7th decades of life. Conservative surgery was used in most cases as the initial treatment. The overall recurrence rate was low and there were 3 cases associated with carcinoma. We conclude that the results of conservative surgery in selected cases are comparable to those using radical methods. A review of the literature is presented and particular attention is dedicated to the literature concerning analysis of p53 expression, HPV and Epstein-Barr infection and apoptosis in inverted papilloma

Determining elastic modulus of the material by measuring the deflection of the beam loaded in bending

U radu je dan teorijski model i projektno rješenje uređaja za određivanje modula elastičnosti na osnovi savijanja, a ne istezanja materijala (ispitnih uzoraka) kao što je uobičajeno. Uređaj je projektiran, realiziran i uspješno testiran u laboratoriju. Provedeno je eksperimentaln o određivanje modula elastičnosti mjerenjem vrijednosti progiba ispitivanih uzoraka materijala pri konstantnom opterećenju. Na bazi teorijskih ovisnosti, dolazi se do vrijednosti modula elastičnosti. Provedeno je mjerenje i analizirane su greške mjerenja, odnosno uređaja.The paper presents a theoretical model and design solution for the device which determines the modulus of elasticity by bending the material (test samples), instead of the usual stretching. The device was designed, assembled and successfully tested in the laboratory. Experimental determination of the elastic modulus was conducted by measuring the deflection of samples under a constant load. Values of the elastic modulus resulted from theoretical relations. Measurement was performed and measurement errors, i.e. device errors, were analysed

Possible Prognostic Significance of P53 and Ki 67 in Inverted Sinonasal Papilloma

The aim of this study is to test the possible prognostic significance of p53 and Ki67 expression in inverted papilloma of the lateral nasal wall and adjacent sinuses regarding their malignant potential and recurrence. 49 biopsies of the lateral nasal wall and adjacent sinuses obtained from 41 patients from three hospitals were investigated. Immunohistochemically demonstrated p53 and Ki67 expression was measured and statistically valuated. p53 immunoreactivity was demonstrated in most of papillomas with carcinomas but only in two benign papillomas, while Ki67 demonstrated stronger immunoreactivity in carcinomas and surrounding epithelium. Immunohistochemical staining of inverted sinonasal papillomas for p53 and Ki67 can give useful information concerning the existence of synchronous carcinoma and, in case of high Ki67, a hint toward possible recurrence

Possible Prognostic Significance of P53 and Ki 67 in Inverted Sinonasal Papilloma

The aim of this study is to test the possible prognostic significance of p53 and Ki67 expression in inverted papilloma of the lateral nasal wall and adjacent sinuses regarding their malignant potential and recurrence. 49 biopsies of the lateral nasal wall and adjacent sinuses obtained from 41 patients from three hospitals were investigated. Immunohistochemically demonstrated p53 and Ki67 expression was measured and statistically valuated. p53 immunoreactivity was demonstrated in most of papillomas with carcinomas but only in two benign papillomas, while Ki67 demonstrated stronger immunoreactivity in carcinomas and surrounding epithelium. Immunohistochemical staining of inverted sinonasal papillomas for p53 and Ki67 can give useful information concerning the existence of synchronous carcinoma and, in case of high Ki67, a hint toward possible recurrence