267 research outputs found
An Investigation Of The Thermal Degradation Of Lignin
The goal of this research was to explore selected non-biological lignin decomposition reactions to determine if these reactions have the potential to generate fuel and chemical intermediates in a commercially feasible manner. Two different strategies were employed: 1) metal doped silica-alumina and γ-alumina catalytic decomposition reactions, and 2) base catalyzed sub- and supercritical water liquefaction.
The first strategy was built upon previous research to explore metal doped silica-alumina and γ-alumina catalytic lignin decomposition reactions in a batch reactor system. Commercially available silica-alumina and γ-alumina catalysts were individually doped with 5 and 10 wt % of molybdenum or copper via a wet impregnation method. All catalysts were characterized with SEM, XRD and EDS analyses. Twelve runs in a Plackett-Burman design were used in a screening study of the significance of seven factors: catalyst support type, catalyst dopant type, dopant concentration, lignin concentration in water, catalyst-to-lignin ratio, reactor stirring rate, and reaction time. Aqueous products were extracted in DCM and analyzed in GC-MS. Solid residues from the reactor were analyzed via TGA and SEM. Screening study results showed that 5 wt% Cu on silica-alumina with 3 g of catalyst and 3 g of lignin in 250 ml of deionized water was the preferred condition to degrade lignin to monomers.
Next, the effect of varying the reaction temperature between 300 and 350 ℃ was investigated at the best reaction conditions from the screening studies. The optimum temperature was found to be around 320 ℃. Lower reaction temperatures (300 ℃) result in more unreacted lignin while higher temperatures (350 ℃) lead to increased formation of char and gaseous products. However, the quantity of monomers produced is still below the commercialization threshold.
The base catalyzed decomposition of lignin to monomeric compounds was studied in a novel continuous flow reactor. In these experiments, 10 wt % lignin was dissolved in a 5 wt % sodium hydroxide in water solution at either sub or supercritical conditions and then fed to a heated tubular reactor. The products from these reactions were collected as gas phase and water-soluble liquid compounds. The gas was quantified by weight difference while the water soluble compounds were acidified and extracted in DCM and analyzed with GC-FID/MS. The solid residues from the acidification treatment were filtered and analyzed with TGA. The morphology of solid residue particles was studied with SEM.
The concentration of monomers was found to increase with increasing temperature in supercritical condition experiments (6 wt %) , all of which were higher than those from the subcritical experiments (4 wt %) where the results showed that the maximum concentration of monomers (mostly creosols) was obtained at 340 ℃ in subcritical water (4.7 wt%). Analysis of solid residues showed that the concentration of partially decomposed lignin was lower in residue from supercritical condition experiments and the solid residues were larger in size compared to the char that was formed at subcritical conditions.
These initial experiments did not result in monomer production at desired levels, but they were comparable to metal-doped experiments results. However, the novel reactor design substantially minimizes concerns due to tar or char formation. Future work is recommended to explore additional reaction strategies using this approach
The Relationship between Managers’ Power Sources and Workers’ Organizational Commitment of Registration Offices of Northern Khorasan-Iran
The role registration offices play in identification is so important that can affect on success of other organizations and institutions of a society. Human force and management of human force is one of factors affecting greatly on viability and efficiency and effectiveness of organizations. Organizations having faithful and attached workers who consider the goal of organization as their own goal, satisfy internally by reaching to that goal, don’t tend to leave their organization and defend from organization interests out of organization may have more efficiency with the least costs. In such organization, the role played by managers and power sources they use in order to obtain the most efficiency from workers is of high importance. In the present paper, power sources used by managers of registration offices in Northern Khorasan are studied and their effect on workers’ organizational commitment is measured in 95% level. The final result indicates that there is a significant relationship between different power sources of managers and workers’ organizational commitment. Keywords: manager’s power; Canonical power; Force Power; Reward Power; Specialization Power; Authority Powe
Procjena metabolizma visokomliječnih holštajnskih krava nakon intravenske primjene bolusa glukoze.
Providing energy demands with emphasis on glucose supply can prevent metabolic disorders in high producing dairy cows. Hence, we hypothesized that bolus intravenous glucose administration may change the concentrations of circulating metabolic biomarkers in order to prevent and control metabolic dysfunctions in dairy cows. Twenty-five multiparous, high producing Holstein dairy cows were divided into 5 equal groups containing early, mid and late lactation, and far-off and close-up dry cows. All cows received dextrose 50 % intravenously at 500 mg/kg, 10 mL/kg/hour. Blood samples were collected from all animals prior to and 1, 2, 3 and 4 hours after dextrose 50 % infusion, and sera were separated to determine glucose, insulin, non-esterified fatty acid, β-hydroxybutyric acid, cholesterol, triglyceride, high, low and very low density lipoproteins. Significantly decreasing patterns of non-esterified fatty acid and β-hydroxybutyric acid were seen in early and mid-lactation and close-up dry cows after glucose administration (P0.05). The results of this study demonstrated that bolus intravenous glucose infusion can influence metabolism in high producing Holstein dairy cows. The changing patterns of circulating metabolic profi le indicated that glucose is an important direct controller of metabolic interactions and responses in dairy cows in various physiological states.Zadovoljenje potreba za energijom, s posebnim naglaskom na opskrbu glukozom, može spriječiti metaboličke poremećaje kod visokomliječnih krava. Stoga se pretpostavlja da intravenska primjena bolusa glukoze može mijenjati koncentracije cirkulirajućih metaboličkih biomarkera s ciljem sprječavanja i kontrole metaboličkih poremećaja u mliječnih krava. Dvadeset pet visokomliječnih krava holštajnske pasmine, višerotki, podijeljeno je u 5 jednakih skupina prema ranoj, srednjoj i kasnoj laktaciji te prema vremenu (kratko ili dugo) do zasušenja. Sve krave su primile 50 %-tnu dekstrozu, intravenski 500 mg/kg, 10 mL/kg/sat. Uzorci krvi prikupljeni su od svih životinja prije, zatim 1, 2, 3 i 4 sata nakon infuzije 50 %-tne dekstroze. U serumu su određene koncentracije glukoze, inzulina, neesterificiranih masnih kiselina, β-hidroksimaslačne kiseline, kolesterola, triglicerida, te lipoproteina visoke, niske i vrlo niske gustoće. Signifikantno (P0,05) promjene u lipidnom profilu. Rezultati ovog istraživanja pokazali su da intravenska infuzija bolusa glukoze može utjecati na metabolizam visokoproizvodnih krava holštajnske pasmine. Promjenjljivost profila cirkulirajućih metabolita ukazuje da je glukoza važan izravan upravljač metaboličkih interakcija, te da je odgovorna za različita fiziološka stanja u mliječnih krava
Kozja beznoitioza u jugozapadnom Iranu
Besnoitia sp. are protozoans that cause a disease affecting the skin, subcutis, blood vessels, mucus membranes, and other tissues. The Toxoplasma gondii-like organisms multiply in endothelial, histocytic and other cells, producing characteristic large, thick-walled cysts filled with bradyzoites. In this study, infected animals originated from the southwest area of Iran. A total of 50 head goats with characteristic sclero-conjunctival cysts of Besnoitia sp. were isolated for further clinical observation. No infected animals other than goats with besnoitiosis were reported in this region. Microscopic examination revealed crescent-shaped organisms with a more pointed anterior than posterior end (banana-shaped morphology) confirming that cysts belong to the genus Besnoitia. Experimental transmission of Besnoitia sp. from these patients resulted in besnoitiosis in goats but not in rabbits and mice. Therefore, B. caprae was accepted as the cause of the infection. It seems that factors such as the presence of thorn remnants in the eyelids, pneumonic coughing goats and a range of flies and ticks could facilitate transmission of the disease.Kozja beznoitioza u jugozapadnom Iranu. Vet. arhiv 77, 435-439, 2007.
SAŽETAK
Vrste roda Besnoitia su praživotinje koje uzrokuju promjene na koži, potkožju, krvnim žilama, sluznicama i drugim tkivima. Te praživotinje po mnogo čemu podsjećaju na mnogo učestaliju praživotinju Toxoplasma gondii. Umnožavaju se u endotelnim stanicama, histiocitima i drugim stanicama tvoreći karakteristične ciste omeđene debelom ovojnicom, ispunjene bradizoitima. U ovom istraživanju invadirane životinje potjecale su iz jugozapadnog dijela Irana. Ukupno je za daljnja istraživanja izdvojeno 50 koza s karakterističnim sklerokonjuktivalnim cistama. Ni u jedne druge vrste nisu zabilježeni znakovi ove bolesti. Mikroskopskom pretragom dokazani su vretenasti organizmi karakteristične građe što je ujedno potvrdilo da je riječ o pojavi beznoitioze. Pokusna beznoitioza izazvana je u koza, ali ne u kunića i miševa te se smatra da je vrsta B. caprae uzrokovala invaziju. Čini se da čimbenici poput ostataka trnja u vjeđama, bolesti dišnog sustava kao i prisutnost dvokrilaca i krpelja, mogu biti pogodovni za prijenos uzročnika
A Highly Efficient Solvent-Free Acetalization of Aldehydes to 1,1-Diacetates Catalyzed by SiO2-Pr-SO3H
1,1-Diacetates are prepared in excellent yields from aldehydes and acetic anhydride under solvent-free conditions at room temperature in short reaction times using catalytic amount of sulfonic acid functionalized silica (SiO2-Pr-SO3H) which could be easily handled and removed from the mixture of reaction.Keywords: 1,1-Diacetates, sulfonic acid functionalized silica, acetalization, solvent-free reaction, SiO2-Pr-SO3
A Case Study of Walkability and Neighborhood Attachment
The neighborhood attachment provides psychological benefits and has positive behavioral consequences for residents and communities Much of the literature examines the impacts of individual and social indicators as predictors of place attachment This research paper concentrates on the place dimension of this bond examining influences of the built environment in the context of perceived walkability on neighborhood attachment and determining which variables of neighborhood walkability have the most significant impact on promoting neighborhood attachment Moreover the effects of neighborhood walkability variables on three main dimensions of neighborhood attachment namely emotional functional and behavioral are compared In this study we draw a random sample of 348 Ekbatan residents aged 15 and above by using the stratified sampling method and a multidimensional scale is adopted to measure neighborhood attachment and walkability The findings confirm that respondents assign high or very high ranks to both variable
Exploring Large Pore Size Alumina and Silica-Alumina Based Catalysts for Decomposition of Lignin
Evaluation of copper doped silica-alumina and γ-alumina catalysts for lignin decomposition was conducted using a suite of chemical analysis protocols that enabled a comprehensive characterization of the reaction product. X-ray diffraction analysis was used to verify the concentration of doped copper on catalyst supports. Then, batch experiments were performed to study the significance of catalyst support type, catalyst dopant concentration, lignin concentration, catalyst-to-lignin ratio, reactor stirring rate and reaction time. Aqueous products were extracted with dichloromethane and analyzed using a detailed gas chromatography-mass spectrophotometry analytical protocol, allowing for quantification of over 20 compounds. Solid residues were analyzed by thermogravimetric analysis and scanning electron microscopy. The highest yield of monomeric products from these screening experiments occurred with 5 wt% Cu on silica-alumina with a 1:1 w/w ratio of catalyst to lignin. A second set of experiments were conducted at these conditions to evaluate the effect of varying the reaction temperature between 300 and 350 ºC. Lower reaction temperatures (300 ºC) resulted in more unreacted lignin while higher temperatures (\u3e350 ºC) led to an increased formation of liquid phase products, but also increased char formation. While the total amount of liquid phase products increased, the combined yield of monomer phenolic products was only 5–7 wt% of the liquid extracted product and statistically independent of temperature and other operational parameters, although the yields of different chemicals varied with temperature. Unlike most pyrolytic processes, the concentration of gas phase products gradually decreased with increasing reaction temperature and became negligible at 400 ºC, while the formation of coke increased with temperature. This seemingly contradictory result is likely due to increased product polymerization occurring at higher temperatures
Comparison of Cardiac Arrhythmias between Late Pregnancy and Early Post-partum Periods in Clinically Healthy Iranian Fat-Tailed Sheep
The current study was conducted to find out the prevalence of cardiac arrhythmias in clinically healthy Iranian fat-tailed sheep in two physiological states, i.e., late pregnancy and early post-partum periods. The electrocardiogram (ECG) was recorded from 32 sheep (early post-partum, n=17 and late pregnant, n=15) without any clinical signs of cardiac diseases. Assessment of ECG revealed that 84.3% of sheep had one or two kinds of cardiac arrhythmias. Two types of cardiac arrhythmias which detected in this study were sinus tachycardia and sinus arrhythmia. The proportion of different cardiac arrhythmias between early post-partum and late pregnant sheep, were significantly (P=0.003) different. Sinus tachycardia was the most frequent arrhythmia recorded in both groups. Since none of the sheep with cardiac arrhythmias exhibited any clinical signs of heart disease at the time of ECG recording, the arrhythmias seen in this study could be regarded as physiological ones
Usporedba srčane električne aktivnosti konja praćene kratkotrajnom elektrokardiografijom i 24-satnim holterom
Assessing equine cardiac electrical activities is essential during a clinical examination of the cardiovascular system. The aim of the present study was to evaluate this activity by two methods to find the more reliable technique in this regard. Hence, standard electrocardiography (for 30 minutes) and Holter monitoring (for 24 hours) were recorded in 20 adult clinically healthy horses. Various parameters of the recorded waves, such as P-R, Q-T and R-R intervals, S-T and P-R segments, P, R, S, and T amplitudes and heart rate, were evaluated. The presence of various arrhythmias was also assessed. All the parameters studied by Holter monitoring were significantly different from standard electrocardiography, except P-R and Q-T intervals and heart rate. Sinus arrhythmia and first and second degree atriventricular blocks were detected by both methods, but a sino-atrial block was present on Holter monitoring. Furthermore, the distribution of cardiac arrhythmias in Holter monitoring was greater than with standard electrocardiography. On the basis of the results of the current research, prolonged Holter monitoring may be considered to be the more reliable method to evaluate the cardiac electrical activity of horses.Procjena srčane električne aktivnosti u konja ključna je u kliničkom pregledu kardiovaskularnog sustava. Cilj ovoga istraživanja bio je usporediti pouzdanost dviju metoda pri praćenju različitih pokazatelja srčane električne aktivnosti. U 20 odraslih, klinički zdravih konja učinjena je standardna elektrokardiografija tijekom 30 minuta i 24-satno praćenje holterom. Procjenjivani su različiti pokazatelji zabilježenih valova kao što su P-R, Q-T i R-R intervali, S-T i P-R segmenti, P, R, S i T-amplitude te srčani otkucaji. Utvrđena je i prisutnost različitih aritmija. Sve vrijednosti dobivene praćenjem holterom znakovito su se razlikovale od onih dobivenih standardnom elektrokardiografijom, osim P-R i Q-T intervala te srčanih otkucaja. Sinusna aritmija te prvi i drugi stupanj atrioventrikularnog bloka otkriveni su objema metodama, no sinusno-atrijski blok utvrđen je samo pri praćenju holterom. Osim toga više je srčanih aritmija otkriveno holterom nego standardnom elektrokardiografijom. Na temelju rezultata novijih istraživanja produljeno praćenje holterom moglo bi se smatrati pouzdanijom metodom u procjeni srčane električne aktivnosti konja
Effect of Long Term Administration of Frozen and Fermented Colostrums of Vaccinated Cows on Performance and Prevention of Neonatal Calf Diarrhea
Diarrhea in calves under 30 days of age is one of the most common syndromes. In order to present a useful and convenient method for reduction of calf diarrhea, thirty newborn Holstein calves, with normal parturition, were divided randomly into three equal groups (T1, T2 and Control (C)). Calves weighing 31-40 kg and more than 40 kg at birth were respectively offered 2 and 2.5 kg of vaccinated cow’s colostrum immediately after birth and the same amounts 4-6 hours later. All calves were fed milk twice daily. Both groups T1 and T2, were fed once daily, 0.8-1 kg of respectively thawed and natural fermented colostrums diluted with 1-1.2 kg cow milk from 2nd to 30th day of their life. Ten calves of Group C were fed only 1.8-2.5 kg warm milk in each meal everyday. Calves were weighed at 0, 10th, 20th and 30th day after birth. Incidence and severity of diarrhea were recorded based on current landmarks. Totally 143 cases of diarrhea recorded. The cumulative incidence rate of diarrhea was significantly (P0.05)
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