20 research outputs found
Physicochemical characterisation of ionic liquids and lactones binary mixtures and their application as electrolytes for lithium-ion batteries
U ovoj doktorskoj disertaciji ispitivani su elektroliti na bazi binarnih smeša imidazolijumovih jonskih tečnosti i laktona koji su pogodni za primenu u litijum-jonskim baterijama. Fizičkohemijska svojstva binarnih smeša jonskih tečnosti na bazi imidazolijum katjona i bis (trifluorometilsulfonil)imidnog anjona i laktona ispitana su u celom opsegu molskih udela i na različitim temperaturama. Na osnovu izmerenih gustina, viskoznosti i električne provodljivosti izračunati su različiti fizičko-hemijski parametri i diskutovane interakcije između komponenata smeša. Ispitana je termička i elektrohemijska stabilnost odabranih elektrolita. Na osnovu dobijenih rezultata, prvo je odabran odgovarajući lakton koji je kasnije kombinovan sa jonskim tečnostima na bazi imidazola, koje se međusobno razlikuju u dužini bočnog niza katjona. Na osnovu fizičko-hemijskih svojstava na različitim temperaturama i pri različitim sastavima binarnih smeša diskutovan je način organizacije njihovih komponenata. U binarne smeše koje su se pokazale kao najperspektivnije sa stanovišta električne provodljivosti, viskoznosti, elektrohemijske stabilnosti i (ne)zapaljivosti dodata je litijumova so. Tako dobijeni ternarni sistemi su okarakterisani u zavisnosti od koncentracije litijumove soli. Odabrani elektroliti upotrebljeni su za ispitivanje performansi litijum-jonske ćelije sa elektrodama na bazi anatas TiO2 nanocevi. Cikličnom voltametrijom i galvanostatskim cikliranjem ispitane su performanse ćelije u toku 350 ciklusa punjenja i pražnjenja. Na osnovu ciklovoltametrijskih merenja izračunati su koeficijenti difuzije jona Li + i energija aktivacije za difuziju. Kombinacijom jonskih tečnosti i laktona moguće je dobiti elektrolite smanjene viskoznosti, povećane električne provodljivosti, povećane termičke stabilnosti usled međusobnog stabilizacionog efekta laktona na imidazolijumove jonske tečnosti.In this doctoral dissertation, binary mixtures based on imidazolium ionic liquids with lactones were tested for use in lithium-ion batteries. The physicochemical properties of binary mixtures of imidazolium based ionic liquids with bis (trifluoromethylsulfonyl)imide anions and lactones were examined throughout the whole composition range and at different temperatures. Based on the measured densities, viscosity and electrical conductivity, various physical chemical parameters and discrete interactions between the components of the mixture are calculated. Thermal and electrochemical stability of selected binary mixtures were examined. Based on obtained results was selected lactone which is later combined with imidazolium based ionic liquid, differing from each other in the length of the cation. Based on the physico-chemical properties at different temperatures and in the different compositions of binary mixtures, the way of organizing their components is discussed. Lithium salt is added to the binary mixtures that have been shown as the most perspective from the standpoint of electrical conductivity, viscosity, electrochemical stability and (non)flammability. The resulting ternary systems are characterized according to the concentration of lithium salt. The selected electrolytes were used to test the performance of the lithium-ion cell with anatase TiO2 nanotubular electrodes. Cyclic voltammetry and galvanostatic cycling tested the cell's performance during the 350 charge and discharge cycles. Based on cyclic voltammetric measurements, the Li + ion diffusion coefficients and activation energies for diffusion were calculated. Combination ionic liquid and lactone could be obtained electrolytes with lower viscosity, higher electrical conductivity, improved thermal stability due to stabilization effect of lactone on imidazolium based ionic liquids
Utjecaj sustava držanja na bolesti papaka i postotak izlučenja u krava holštajnske pasmine
The objectives of this research were to investigate the effect of the housing system (tie-stall and free-stall barns) on the prevalence of hoof diseases/disorders, as well as on the percentage of culling in 6,348 Holstein dairy cows from 5 farms. During the three months of research the hoof care service on all farms collected records of causes of lameness, diagnoses and treatments. Functional and corrective hoof trimming was conducted by a professional farm trimmer. When all the registered diseases/disorders were observed as a percentage (all diseases = 100%), it was noticed that both housing systems were similarly affected by the same diseases/disorders. In this regard, White Line Disease occurred in both systems in prevalence of 0.5% - 1%, Toe Ulcer and Necrosis in 3% - 6%, Rusterholz Ulcer / Sole Ulcer in 20% - 23%, Digital Dermatitis in 18% - 20%, Interdigital Hyperplasia / Tyloma in 10% - 12%, Panaritium / Interdigital Phlegmon in 0.7% - 0.77%, while the prevalence of Mechanical Injury was negligible and in similar amounts - 0.2% - 0.5%. Cows in the free-stall barns were much more burdened with Dermatitis Interdigitalis / Heel Erosion Disease (39.11%) compared to cows in the bound housing system (20.40%). In contrast, diagnosed acute, chronic and haemorrhagic Laminitis was significantly more pronounced in the tie-stall barns (18.61%) than in the free-stall barns (0.88%). In the statistical analysis conducted, statistically significantly more diseases/disorders were registered in the tie-stall system than in the free housing system (P0.05).Cilj je istraživanja bio utvrditi utjecaj držanja (vezani ili slobodni sustav) na pojavnost bolesti i promjena na papcima, kao i na postotak izlučenja u krava holštajnske pasmine. Uključeno je 6348 krava s pet farmi, za koje su tijekom tri mjeseca prikupljeni podaci o obradi i njezi papaka, uzrocima šepavosti, dijagnozama te redovitim liječenjima. Funkcionalno i korektivno obrezivanje papaka provele su osobe educirane za to. Promotre li se svi registrirani poremećaji i bolesti postotno (sve bolesti = 100 %), zapaža se da su oba sustava držanja bila u sličnoj mjeri opterećena istim bolestima. U skladu s tim, bolest bijele linije opažena je u oba sustava, s pojavnošću od 0,5 do 1%, čir i nekroza papka od 3 do 6 %, Rusterholzov čir / Ulcus soleae od 20 do 23 %, digitalni dermatitis od 18 do 20 %, interdigitalna hiperplazija / tilom od 10 do 12 %, panaricij / interdigitalna flegmona od 0,7 do 0,77 %, dok je postotak mehaničkih ozljeda bio vrlo sličan i zanemariv (0,2 – 0,5 %). Krave u slobodnom sustavu držanja bile su mnogo više opterećene bolešću interdigitalni dermatitis / erozija pete (39,11 %) u odnosu na krave u vezanom sustavu držanja (20,40 %). Suprotno tomu, pojavnost akutnog, kroničnog i hemoragijskog laminitisa bila je znakovito veća u vezanom sustavu držanja (18,61 %) nego u slobodnom (0,88 %). Na osnovi provedenih statističkih proporcija i Z-testa tijekom istraživanog razdoblja, registrirano je statistički znakovito više bolesti i poremećaja u vezanom sustavu držanja nego u slobodnom (P0,05)
Učinak dipping profila gestacijske hipertenzije na majčine simptome i fizikalne nalaze, porođajnu težinu i prijevremeni porođaj
The study aimed to determine if the non-dipping pattern of blood pressure (BP)
influences preterm delivery in gestational hypertension (GH), but also maternal clinical findings and
birth weight. Sixty women with GH, i.e. 30 women with a dipping BP profile (control group) and 30
non-dippers (study group), were included in the study. Echocardiography was performed in all subjects,
as well as ambulatory blood pressure monitoring (ABPM) during third trimester. ABPM was
repeated 6-8 weeks after delivery. Thirteen women with preterm delivery were classified as non-dippers
and only four as dippers (p=0.01). The average and peak systolic and diastolic night-time BP had
negative linear correlation with birth weight (p<0.0005). Total vascular resistance (p<0.0005) and
mass index (p=0.014) were significantly higher as compared with women with term delivery, while
ejection fraction (EF) (p=0.007) and circumferential systolic velocity (p=0.042) were significantly reduced
in the preterm delivery group. Multivariate binary logistic regression identified the average
night-time systolic BP, left ventricular mass index and EF as independent predictors of preterm delivery.
Study results suggested a relationship of the non-dipping BP pattern in GH with preterm delivery,
birth weight, and maternal clinical findings.Cilj ovoga istraživanja bio je utvrditi povezanost non-dipping profila krvnog tlaka (KT) s prijevremenim porođajem,
porođajnom težinom novorođenčeta te kliničkim i ehokardiografskim parametrima kod žena s gestacijskom hipertenzijom
(GH). Istraživanje je obuhvatilo 60 žena s GH, 30 s dipping profilom KT (kontrolna skupina) i 30 non-dippera (ispitna skupina).
Sve žene podvrgnute su kompletnoj ehokardiografiji i 24-satnom ambulantnom praćenju krvnog tlaka (ambulatory
blood pressure monitoring, ABPM) tijekom trećeg trimestra, a ABPM je ponovljen 6-8 tjedana nakon porođaja. Ukupno 17
žena imalo je prijevremeni porođaj. Trinaest žena s prijevremenim porođajem imalo je non-dipping profil KT, dok su samo
četiri žene imale dipping profil KT (0,01). Prosječni i maksimalni sistolički i dijastolički noćni KT imali su negativnu linearnu
korelaciju s porođajnom težinom (p<0,0005). Ukupna vaskularna rezistencija (p<0,0005) i indeks mase miokarda lijeve
klijetke (p=0,014) bili su znatno viši u skupini žena s prijevremenim porođajem, dok su parametri sistoličke funkcije, tj.
ejekcijska frakcija (EF) (p=0,007) i brzina cirkumferentnog skraćenja miokarda lijevog ventrikla (p=0,042) bili statistički
značajno sniženi u skupini žena s prijevremenim porođajem. Multivarijatna regresijska analiza pokazala je da su prosječni
noćni sistolički KT, indeks mase lijevog ventrikla i EF identificirani kao nezavisni prediktori prijevremenog porođaja. Rezultati
istraživanja pokazali su da postoji povezanost između non-dipping profila KT s prijevremenim porođajem, porođajnom
težinom novorođenčeta i poremećajem hemodinamskog statusa majke u GH
Thermo-Analytical and Compatibility Study with Mechanistic Explanation of Degradation Kinetics of Ambroxol Hydrochloride Tablets under Non-Isothermal Conditions
Ambroxol hydrochloride (AMB), used as a broncho secretolytic and an expectorant drug, is a semi-synthetic derivative of vasicine obtained from the Indian shrub Adhatoda vasica. It is a metabolic product of bromhexine. The paper provides comprehensive and detailed research on ambroxol hydrochloride, gives information on thermal stability, the mechanism of AMB degradation, and data of practical interest for optimization of formulation that contains AMB as an active compound. Investigation on pure AMB and in commercial formulation Flavamed® tablet (FT), which contains AMB as an active compound, was performed systematically using thermal and spectroscopic methods, along with a sophisticated and practical statistical approach. AMB proved to be a heat-stable and humidity-sensitive drug. For its successful formulation, special attention should be addressed to excipients since it was found that polyvinyl pyrrolidone and Mg stearate affect the thermal stability of AMB. At the same time, lactose monohydrate contributes to faster degradation of AMB and change in decomposition mechanism. It was found that the n-th order kinetic model mechanistically best describes the decomposition process of pure AMB and in Flavamed® tablets
Effect of Zwitterionic Additive on Electrode Protection through Electrochemical Performances of Anatase TiO<sub>2</sub> Nanotube Array Electrode in Ionic Liquid Electrolyte
In this work, a functionalized zwitterionic (ZI) compound 1-butylsulfonate-3-methylimidazole (C1C4imSO3) was synthesized and tested as an additive to LiTFSI/C2C2imTFSI ionic liquid-based electrolytes for lithium-ion batteries. The structure and purity of C1C4imSO3 were confirmed by NMR and FTIR spectroscopy. The thermal stability of the pure C1C4imSO3 was examined by simultaneous thermogravimetric–mass spectrometric (TG–MS) measurements and differential scanning calorimetry (DSC). The LiTFSI/C2C2imTFSI/C1C4imSO3 system was tested as a potential electrolyte for lithium-ion batteries by using anatase TiO2 nanotube array electrode as the anode material. This electrolyte with 3% C1C4imSO3 showed significant improvement of lithium-ion intercalation/deintercalation properties, such as capacity retention and Coulombic efficiency compared to electrolyte without additive
Electrochemical study of anatase TiO2 nanotube array electrode in electrolyte based on 1,3-diethylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid
The density, viscosity and electrical conductivity of ionic liquid 1,3-diethylimidazolium bis(trifluoromethylsulfonyl)imide, (C2C2imTFSI), and 0.5 M solution of LiTFSI in C2C2imTFSI were determined at different temperatures. The LiTFSI/C2C2imTFSI system was tested as a possible electrolyte for lithium-ion batteries by using anatase TiO2 nanotube array electrode as anodematerial for the first time. The electrochemical testing has shown not only the improvement of lithium-ion insertion/deinsertion properties by increasing temperature but also the existence of a decomposition of the electrolyte, detecting the change of colour. The decomposition of electrolyte leads to the formation of a film on the surface of the electrode which improves Coulombic efficiency during cycling
Povezanost između uzrasta pri prvom teljenju i proizvodnje u prvoj laktaciji sa osobinama dugovečnosti kod mlečnih krava
The objective of this research was to determine the association between age at first calving (AFC) and milk production in the first lactation of longevity traits for Holstein cows. The research was conducted on 2307 cows raised on 4 farms in AP Vojvodina. The cows were culled in the period from 2017 to 2018. The cows belonged to the group of Holstein Friesian breed of cattle. Cow longevity was observed using three parameters: number of lactations (NL), lifetime milk yield (LMY) and length of productive life (LPL). The research involved the influence of the farm on which the animals realized their production, the season of first calving. A mean value obtained for the length of productive life in the analysed population was 1207 days (3.30 years on average). During this period the animals on average realized 2.45 lactations and produced on average 18798 kg milk. All studied traits showed a high level of variability. From these data, the study sought to determine the influence of factors on the traits of longevity, our research present that studied factors showed high statistical significance on these traits except in the case of the season of first calving where a statistical significance effect wasn't observed. The season of first calving did not affect the animal traits for longevity and, generally, didn't affect the calving interval. Regarding the obtained correlation data between age at first calving and length of productive life, it can be concluded that belated AFC leads to reduced reproductive performance.Sprovedeno istraživanje imalo je za cilj da utvrdi povezanost između uzrasta pri prvom teljenju i proizvodnje mleka u prvoj laktaciji sa osobinama dugovečnosti za krave holštajn-frizijske rase. Istraživanjem je obuhvaćeno 2307 krava, sa 4 različite farme sa teritorije AP Vojvodine. Krave su izlučene u periodu od 2017 do 2018 godine. Dugovečnost krava je posmatrana kroz tri pokazatelja: broj ostvarenih laktacija (NL), životna količina proizvedenog mleka (LMY) i dužina produktivnog života (LPL). Prosečno trajanje produktivnog života za sva grla uključena u analizu iznosilo je 1207 dana (3.30 godine u proseku). Grla obuhvaćena analizom u toku svog produktivnog života su prosečno proizvela 18798 kg mleka. Broj laktacija koje je svako grlo prosečno ostvarilo u toku trajanja svog produktivnog života iznosio je 2.45, pri čemu su svi ispitani parametri pokazali visok nivo varijabilnosti. U istraživanju su ispitani fiksni uticaji farme na kojoj je grlo proizvodilo, uzrasta pri prvom teljenju, sistema proizvodnje i sezone pri prvom teljenju na osobine dugovečnosti i međutelidbeni interval, korišćenjem linearnog modela. Na osnovu rezultata dobijenih istraživanjem, fiksni faktori su pokazali visoku statističku značajnost za ispitivane osobine, osim u slučaju sezone pri prvom teljenju, gde nije ispoljena statistička značajnost za osobine obuhvaćene istraživanjem. Na osnovu rezultata, utvrđena je povezanost između uzrasta pri prvom teljenju i dužine produktivnog života, pri čemu se može zaključiti da su kraći produktivni život imale životinje koje su se kasnije telile
Greener sample preparation method for direct determination of Cd(II) and Pb(II) in river sediment based on an aqueous biphasic system with functionalized ionic liquids
Although sample preparation, as an unavoidable step of the analytical process should be simple, it is very often identified as a bottleneck. Simplicity of sample preparation based on cost-effective and non-hazardous materials is mandatory for any sustainable and environmental friendly approach. Aqueous biphasic systems (ABS), based on functionalized ionic liquids (FILs) are acceptable alternatives to classical extraction procedures, due to the replacement of organic solvent with diluted aqueous-soluble ionic liquids. In this work, two water soluble FILs based on 2-mercaptobenzothiazolate anion, [mbt]: 1-butyl-3-methylimidazolium [mbt] ([bmim][mbt]) and 1-ethyl-3-methylimidazolium [mbt] ([emim][mbt]), were designed and synthesized in order to selectively extract Cd(II) and Pb(II) from the river sediment. It was found that [mbt]– anion acts as the ligand and forms complexes with Cd(II) and Pb(II) which are responsible for their efficient extraction, while cation is more responsible for the formation of ABS. Partition coefficients of 408 and 180 for Cd(II) and Pb(II), respectively, were obtained using ABS based on [bmim][mbt]. Direct extraction of Cd(II) and Pb(II) from the river sediment has been investigated and obtained optimal conditions are: 60 min direct contact of the aqueous solution of [bmim][mbt] and the sediment sample at 90 °C, followed by formation of ABS upon addition of potassium citrate. Using AGRE and AGREEprep tools greenness of the proposed method for direct extraction of Cd(II) and Pb(II) from the sediment are calculated. Obtained values of 0.69 and 0.71 for Cd(II) and Pb(II) extraction, respectively, showed a high level of the greenness of the proposed method
Physicochemical Investigations of a Binary Mixture Containing Ionic Liquid 1-Butyl-1-methylpyrrolidinium Bis(trifluoromethylsulfonyl)imide and Diethyl Carbonate
Densities, viscosities, and electrical conductivities were determined and discussed for a binary mixture containing 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid, [bmpyrr][NTf2], and diethyl carbonate (DEC) as a function of temperature (T = 293.15-323.15 K) at atmospheric pressure (p = 0.1 MPa) over the entire range composition. Based on experimental density data, the related excess molar volumes were calculated and fitted using Redlich-Kister's polynomial equation. The Casteel-Amis equation was used to correlate data obtained from electrical conductivity measurements. The effect of viscosity on electrical conductivity was discussed by the Walden rule. The Bahe-Varela theory, derived from the the pseudo-lattice model, has been successfully applied to explain the influence of the mixture composition on electrical conductivity. Based on physicochemical characterization supported with computational simulations for binary mixtures ([bmpyrr][NTf2] + DEC), the interactions between these components were discussed. © 2019 American Chemical Society