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PL
Przedstawiono wyniki badań nad skutecznością inhibitorów ureazy NBPT i 2-NPT w ograniczaniu strat azotu z nawozów zawierających azot amidowy. Badaniom poddano nawozy Pulrea®(mocznik), RSM, RSMS oraz Pulaska®. Potwierdzono dużą skuteczność NBPT i 2-NPT w inhibitowaniu enzymatycznej reakcji rozkładu mocznika.
EN
Two urease inhibitors were added (0.1–0.25%) to 4 amide fertilizers to reduce NH₃ emissions. The reduction of NH₃ loss was not less than 77% when compared to the fertilizers without additives. The o-NO₂C₆H₄NHP(O)(NH₂)₂ inhibitor was more efficient than the com. BuNHP(S)(NH₂)₂ one.
PL
Przeprowadzono badania nad trzema wariantami ograniczenia emisji NOₓ do atmosfery podczas spalania biomasy w kotle małej mocy. W wariancie pierwszym do komory spalania podawano mocznik w strumieniu sprężonego powietrza, w drugim roztwór mocznika wtryskiwano w okolice palnika biomasowego, a wariancie trzecim biopaliwo było spalane po wcześniejszym wymieszaniu go z mocznikiem. Wyznaczono rozkład temperatury w komorze spalania. Określono punkty podawania mocznika i roztworu mocznika w odpowiednim oknie temperaturowym. Zbadano skład chemiczny oraz zapylenie spalin. Wyznaczono stopnie zmniejszenia zanieczyszczeń i zasugerowano najlepsze rozwiązanie w perspektywie spełnienia wymogów dyrektywy Ecodesign.
EN
Wood pellets were burned after addn. of (NH₂)₂CO (0.5-2.5% by mass) in a low-power boiler under varying conditions. The 1st method was based on burning pellets in the presence of solid (NH₂)₂CO, which was fed in a stream of compressed air. The 2nd method consisted in the injection of (NH₂)₂CO soln. near the burner, and the 3rd one was based on the burning of pellets previously mixed with (NH₂)₂CO. In terms of NOₓ redn., the best results were obtained fot the 3rd method and the worst ones for the 2nd method. The addn. of (NH₂)₂CO 1.5 or 2.5% by mass was recommended. Particulate matter emission were higher at the 3rd method and lower at the other ones.
EN
Catalytic properties of activated carbons oxidized, treated with N-compounds, and promoted withcopper were studied in selective catalytic reduction NOXby ammonia (NH3-SCR). The modificationof the catalysts consisted of a series of steps (pre-oxidation of activated carbon, impregnation with urea,impregnation with copper). The physicochemical properties of the obtained samples were determinedusing X-ray diffraction, FT-IR spectroscopy, and low-temperature N2sorption. The modification withcopper improved the catalytic activity and stability of the catalysts. All the functionalized carbon dopedwith copper reached more than 90% of NO conversion and CO2did not exceed 240 ppm at 220◦C.The sample doped with 5 wt.% Cu had the maximum NO conversion of 98% at 300◦C. The maximumN2O concentration detected for the same sample was only 55 ppm, which confirmed its selectivity.
4
EN
The standard theory of mass transport in dialyzer for water solutions was extended for solutes distributed in both plasma (PW) and erythrocyte intracellular (EW) water. Blood flow was divided into two separate flows of PW and EW with the diffusive exchange of solutes across cellular membrane (CM). Diffusive permeability of CM for urea and creatinine were assumed according to literature data. Computer simulations based on partial differential equations demonstrated that urea diffuses fast across CM and can be approximately considered as distributed uniformly in both blood flow components. In contrast, creatinine can be considered as distributed only in PW flow during the passage along the dialyzer. Therefore, the traditional formula for dialyzer clearance can be applied for urea and creatinine with the adjustment of their effective ‘‘blood’’ flow, but not for solutes with intermediate molecular mass. In vivo clearances of urea and creatinine were, as expected, lower than the respective theoretical predictions based of the diffusive permeability, P, times membrane surface area, A, parameters, PA, for dialyzer membrane, estimated for water solutions, by 33.6 ± 10.9% for creatinine and 10.8 ± 9.4% for urea. The estimated in vivo PAs were for creatinine 65.4 ± 26.0% and for urea 32.0 ± 10.9% lower than in vitro values provided by manufacturers. The much higher drop in clinical clearance/PA for creatinine than for urea suggests that the exchange of creatinine between plasma and dialysis fluid needs to be adjusted for the reduction of the dialyzer membrane surface area, which is effectively available for creatinine, caused by the presence of erythrocytes.
EN
This study investigated a mechanochemical (MC) process for synthesizing a slow-release urea fertilizer by cogrinding the starting materials of (NH2)2CO and amorphous kaolinite in a planetary ball mill. The tests with kaolinite contents ranging from 25 to 75 wt. %, milling time ranging from 1 (h) to 3 (h) and mill rotational speeds from 200 to 700 rpm were performed to evaluate the incorporation of (NH2)2CO and release of nitrogen into the solution. The analyses conducted using XRD, TGA, FT-IR and KNDU (Kjeldahl Nitrogen Determination Unit) indicated that the MC process was successfully applied to incorporate (NH2)2CO into the amorphous kaolinite structure. The release of nitrogen from the system (kaolinite-(NH2)2CO) when dispersed in water for 24 h reached up to 20% at 25% wt of kaolinite. Moreover, under the milling speed conditions for the system (kaolinite–(NH2)2CO), release of nitrogen reached between 25 and 40%. These results indicated that the MC process can be developed to allow amorphous kaolinite to act as a carrier of nitrogen nutrients to be released slowly for use as fertilizer.
6
Content available remote Moja droga do poliuretanów
EN
Several mixtures, based on urea, urea hydrogen peroxide complex (UHP), triacetone triperoxide (TATP) with some inorganic oxidants were studied by means of ballistics mortar with TNT as a reference standard. The detonation pressure, P, detonation velocity, D, detonation heat, Q, and volume of gaseous product at standard temperature and pressure conditions (STP condition) were calculated by the mean of Explo5 V6.3. The relatively high explosive strength of some samples relative to the TNT charge, focuses on the positive influence of hydrogen peroxide presence in these mixtures, with advantage in the form of its complex with urea (i.e. as UHP). This influence connects with hydroxi-radical in the mixture under its initiation (as the first intermediate of this initiation reaction).
EN
Urea manufacturing discharge contains a high load of nitrogen, a pollutant which needs advanced technologies to be reduced to desirable levels. However, these advanced technologies are expensive due to the complex process and cost of chemicals and maintenance. Phytoremediation has been recently considered for N removal from various wastewaters. However, the common phytoremediation plants (reeds and grasses) are not able to remove N effectively due to the recyclable nature of N through decomposition processes. Therefore, they require periodic harvestings which impose a high cost on system. In this study, the growth and phytoremediation potential of teak (Tectona grandis), a tropical timber plant, to treat the urea manufacturing wastewater was evaluated. Eight month old teak seedlings received 4 different concentrations of N in bench-scale constructed wetlands every 4 days for 8 weeks. The solution volumes supplied to each container and plant biomass, N recovery, and tissue nutrient concentration were measured. Teak plants showed an escalation in wastewater N uptake with increasing amount of supplied N. Total dry weight was positively correlated with total N supplied. Teak seedlings showed a considerable potential for removing nitrogen when they were supplied with up to 5 g N per pot volume (4 dm3) during a two-month experiment.
9
Content available remote Wybrane rozwiązania z chemii i technologii polimerów
PL
Dokonano przeglądu prac Autora i jego współpracowników, opublikowanych w latach 1967–2011, z zakresu wykorzystania mocznika w chemii polimerów. Z mocznika otrzymywano nie tylko żywice i tworzywa mocznikowo-formaldehydowe, ale także melaminę, a z niej żywice melaminowo-formaldehydowe, karbaminiany i poliuretany bezizocyjanianowe, cyjanamid i policyjanamid, kwas izocyjanurowy oraz kwas izocyjanowy i cyjaniany metali, a z nich z kolei izocyjaniany bezfosgenowe. Przedstawiono też reakcje karbidu oraz wykorzystanie tworzyw skóropodobnych i odpadów skór, frakcji glicerolowej z produkcji biodiesla, odpadów poliuretanów oraz skrobi.
EN
A review, with 62 refs., of author’s own papers and patents concerning the use of urea and waste materials in polymer chemistry.
PL
Przedstawiono nową technologię produkcji granulowanych nawozów azotowo-fosforowych typu USP (urea-superphosphate) umożliwiającą wytwarzanie produktu w sposób ciągły (bez konieczności dojrzewania półproduktu). W procesie zachodzi rozkład surowców fosforowych roztworem mocznika w kwasie siarkowym przy wyższej zawartości wody w układzie reakcyjnym niż w znanych dotychczas rozwiązaniach technologicznych. Przedstawiono schemat blokowy instalacji oraz zalecane parametry procesowe.
EN
An industrial process for prodn. of urea-superphosphate fertilizer was improved to be carried out in a continuous manner. Urea and raw phosphate are pulped in concd. H2SO4. The resulting sludge is granulated, dried, classified, cooled and stored.
PL
Badano zdolność mocznika do tworzenia połączeń addycyjnych ze składnikami pulp superfosfatowych, takimi jak CaSO4 nH2O (gdzie n = 0–2) i Ca(H2PO4)2⋅H22O. Reakcje prowadzono ucierając wysuszony nawóz superfosfatowy z mocznikiem w młynie moździerzowym lub dodając mocznik do reaktora rozkładu fosforytu kwasami (H2SO4 lub H3PO4). Skład fazowy produktów badano metodą dyfrakcji rentgenowskiej. Stwierdzono, że najłatwiej przebiega reakcja mocznika z Ca(H2PO4)2⋅H2O, a w dalszej kolejności z CaSO4⋅2H2O i CaSO4⋅0,5H2O. W żadnym z prowadzonych doświadczeń nie zaobserwowano reaktywności mocznika z bezwodnym CaSO4.
EN
Urea additive compds. with superphosphate pulp components (Ca(H2PO4)2⋅H2O and CaSO4⋅nH2O, where n = 0–2), were prepd. The exps. were carried out (i) by milling urea with a dry superphosphate fertilizer in a lab. mortar grinder or (ii) by urea addn. to the reactor after phosphate rock decompn. with H2SO4 or H3PO4. The phase compn. Of products was studied by X-ray powder diffraction method. Ca(H2PO4)2⋅H2O was more reactive than CaSO4⋅2H2O and CaSO4⋅0.5H2O in the urea complexation. The reactivity of anhyd. CaSO4 towards urea was not obsd. in any expt.
EN
Air pollution has become an important worldwide problem. The European Commission credits road and water transport as the major source of NOx pollution, and of being responsible for around 50% of the total air pollution in urban areas. During the last decade, the use of SCR technologies have gained popularity as a method for NOx reduction, the technology is widely considered as one of the solutions for road transport emissions. This paper presents a review of the different SCR system designs derived from the various factors and regulations in the automotive industry which have influenced the technology, along with a parametric study of a proprietary SCR system for heavy duty application.
EN
The distribution, concentrations and origin of urea were studied in surface and profundal waters of meso-eutrophic and highly eutrophic parts of The Great Mazurian Lake System (GMLS) during spring – autumn period. Urea concentrations varied from 0.25 µM in surface layer to 3.36 µM in profundal zone of studied lakes and were in the range of concentrations noted in other non-polluted freshwater habitats. In the photic zone of lakes of GMLS Urea N made up to 10 % the total DON pool and often exceeded 2-3 times of NH4+-N concentrations. Pattern of changes in urea concentrations observed during three-years study excludes external urea input and suggests supplementation of lake waters with this compounds by phytoplankton decomposition processes. Generally, urea concentrations were negatively correlated with the trophic state index calculated from “algal” as well as from “bacterial” determinants. However, more detailed analysis showed that the relationships between production and assimilation of urea by various plankton components as well as the ecological role of this compound in meso- and eutrophic lakes could be different.
PL
Zbadano wpływ substancji pomocniczych stosowanych w produkcji klejów skrobiowych na przebieg kleikowania oraz właściwości reologiczne natywnej skrobi kukurydzianej. Zawiesiny natywnej skrobi kukurydzianej, odmiany koński ząb, poddawano kleikowaniu w wiskografie RVA, a następnie umieszczano w cylindrze pomiarowym reometru HAAKE i badano lepkość w trybie kontrolowanej szybkości ścinania (CR). Do sporządzania zawiesin skrobiowych stosowano wodę destylowaną, roztwory mocznika, azotanu(V) sodu i glikolu etylenowego. Gotowe kleiki analizowano metodą rozmazu mikroskopowego, po wybarwieniu za pomocą płynu Lugola. Stwierdzono, że dodatek mocznika powoduje obniżenie temperatury kleikowania, zmianę kształtu krzywej kleikowania skrobi oraz wzrost lepkości końcowej otrzymanego kleiku. Stwierdzono, że dodatek azotanu(V) sodu powoduje wydłużenie czasu kleikowania i stabilizuje lepkość. Glikol etylenowy dodany do zawiesiny wywiera mniejszy wpływ na kleikowanie skrobi niż mocznik i azotan. Skrobia kukurydziana tworzy kleiki lub zawiesiny rozrzedzane ścinaniem, których właściwości reologiczne wyraźnie zmieniają się w czasie.
EN
The effects of the additives used in starch adhesives production on the pasting process and rheological properties of native corn starch were investigated. Suspensions of the starch of Indentata variety (6 %) prepared in distilled water or aqueous solutions of urea (2.5 %), sodium nitrate(V) (2.5 %) and ethylene glycol (1.5 %) were subjected to a controlled pasting in RVA viscometer. The obtained pastes were placed in a measuring cylinder of HAAKE rheometer and the viscosity measurements were performed using controlled shear rate (CR) mode at shear rates of 0—600 s-1. The paste smears were analyzed under a microscope after staining with Lugol's solution. It was found that the addition of urea caused a reduction in the pasting temperature, change in the shape of pasting curve as well as 30 % increase in the final viscosity (Table 1). The addition of sodium nitrate(V) led to an increase in the pasting time, decrease of the viscosity drop and reduced viscosity increase during cooling (Fig. 1). The influence of ethylene glycol additive on the pasting process was less significant than that of urea and sodium nitrate(V). Corn starch forms pastes or shear thinning suspensions with a distinct change in the rheological properties over time.
15
Content available SCR systems for NOx reduction in heavy duty vehicles
EN
Air pollution has become an important worldwide problem. The European Commission credits road and water transport as the major source of NOx pollution, and of being responsible for around 50% of the total air pollution in urban areas. In Poland, around 45% of the country NOx emissions are attributed to transportation. During the last decade, the use of SCR technologies have gained popularity as a method for NOx reduction, the technology is widely considered as one of the solutions for road transport emissions. SCR technology had previously been employed in stationary plants, maritime transportation and other installations using combustion processes in which exhaust conditions are easier to control. The advance on the technology led to the introduction of the first heavy-duty vehicle with an SCR system into the market in 2004. New technologies and applications are constantly appearing, for example, SCR exhaust gas cleaning systems for reciprocating engines are still under development and compression ignition engines can be found in a number of different applications. The technology still needs to be studied and improved as constant problems and knowledge is required in issues such as urea injection, crystallization and NOx reduction efficiency. Moreover, the designs intended for heavy duty vehicles need to meet vehicle limitations and EURO emissions restrictions. This paper presents a review of the different SCR system designs derived from the various factors and regulations in the automotive industry, which have influenced the technology, along with a parametric study of a proprietary SCR system for heavy-duty application.
PL
Ocena skuteczności inhibitora ureazy NBPT w ograniczaniu emisji amoniaku z mocznika i RSM, nawozów powszechnie stosowanych w mineralnym żywieniu roślin uprawnych, była głównym celem badań doświadczalnych przeprowadzonych w latach 2011-2012 w kilku pomorskich gospodarstwach rolnych. W warunkach doświadczenia polowego, przeprowadzonego na trwałych użytkach zielonych, położonych na madzie średniej pylastej stwierdzono, że po zastosowaniu nawożenia azotowego pod drugi odrost traw, w dawce 60 kg N·ha-1, straty amoniaku po upływie 4-5 dni od aplikacji nawozów wynosiły: z mocznika -16,0%, z mocznika stabilizowanego inhibitorem NBPT- 4,3% w stosunku do dawki czystego składnika. Zatem można przypuszczać, że wykorzystanie do stabilizacji mocznika inhibitora ureazy NBPT spowodowało redukcję strat amoniaku o około 73%. W doświadczeniach polowych przeprowadzonych na plantacjach rzepaku ozimego i pszenicy, nawożonych roztworem saletrzano – mocznikowym RSM-28, stwierdzono również, że wzbogacenie nawozu o inhibitor urazy NBPT powoduje wyraźne obniżenie emisji amoniaku. Na plantacji rzepaku ozimego, przy dawce 100 kg N·ha-1, dodanie inhibitora do roztworu RSM skutkowało redukcją gazowych strat azotu o ponad 50% w stosunku do strat tego składnika wykazanych w wariancie bez inhibitora. W drugim doświadczeniu przeprowadzonym na poletku z pszenicą ozimą, przy dawce 60 kg N·ha-1, dodanie do roztworu RSM inhibitora NBPT zmniejszyło straty amoniaku o ponad 80% w stosunku w wariantu nawożenia gdzie inhibitora nie zastosowano. We wszystkich przypadkach obniżenie emisji amoniaku miało również wpływ na zwiększenie masy plonu, co w ostatecznym rachunku zdecydowanie podnosiło nie tylko ekonomiczną ale i ekologiczną efektywność prowadzonej produkcji roślinnej.
EN
The assessment of effectiveness urea inhibitor (NBPT) in mitigation ammonia emission from urea and urea ammonium nitrate solutions (UAN) - fertilizers widely applied in mineral fertilization of plants was objective of this experimental research. Experimental study was conducted in 2011 and 2012 year in several farms located in Pomerania region. Conditions of field experiment, placed in alluvial soils, stated that losses of nitrogen after nitrogen fertilization – 60 kg N ∙ ha-1, for second cuts of grass, after 4 to 5 days, in urea experiment was about 16,0% and with stabilized urea (with NBPT) 4,3% to the initial amount of nitrogen. Based on the experimental data using of urea inhibitor like NBPT may cause reduction of ammonia emission by 73%. Experiments in field conditions carried out at winter rape and wheat plant fertilized using urea ammonium nitrate solution (UAN-28) shows that enrichment UAN with inhibitor of urease (NBPT) decrease ammonia emission. Winter rape plant fertilized by 100 kg N∙ha-1 with addition of inhibitor to UAN solution resulted in reduction of nitrogen losses up to 50% than applied without inhibitors. Second experiment carried out at winter wheat plant fertilized by 60 kg N∙ha-1 with addition to UAN solution inhibitor (NBPT) decreased ammonia losses to 80% in comparison to experiment of fertilization without using inhibitor. In all researches decreasing of ammonia emission caused improvement of yields. This results underline that using inhibitors improve economical and environmental efficiency at plant production level.
EN
The results of the precipitation of calcium carbonate from a waste post-distillation liquid (DS) and a sodium bicarbonate saturated solution – both from the Solvay method – in the presence of urea are presented. The investigation was carried out at 293 K and 343 K. Reagent dosage times of 1, 5, 10, 20 and 30 min, and urea concentrations of 5, 6 and 10 mol/dm3 were applied. The granulometric composition, the values of bulk and packing densities and the absorptiveness sorption of water and paraffin oil from the obtained calcium carbonate were investigated.
EN
The paper is a review of the literature, including studies carried out with involvement of the author, concerning the high thermal stability of products formed by ring-opening of parabanic acid. Asignificant advantage of discussed reactions is that environmentally friendly alkylene carbonates have been applied as hydroxyalkylating agents. The cited results of structure and properties investigations of the products of urea and parabanic acid reaction with alkylene carbonates prove that the presence of carbamic groups has an impact on their high thermal stability.
PL
Artykuł stanowi przegląd literatury, uwzględniający doniesienia z badań własnych, prowadzonych z udziałem autorki, na temat dużej odporności termicznej produktów powstających wskutek otwarcia pierścienia kwasu parabanowego, czyli produktów niezawierających w swej strukturze pierścieni trioksoimidazolidynowych. Istotną zaletą omawianych reakcji jest to, że jako czynniki hydroksyalkilujące zastosowano przyjazne ekologicznie węglany alkilenowe. Przytaczane wyniki badań struktury i właściwości otrzymanych produktów reakcji mocznika i kwasu parabanowego z węglanami alkilenowymi dowodzą, że obecność ugrupowania karbamidowego ma wpływ na ich wysoką odporność termiczną.
EN
Three series of some novel chalcone based urea, thiourea and acetamide derivatives were designed, synthesized and screened for their antimicrobial and antifungal activities. All the synthesized compounds are first reported. The structures of the compounds were elucidated with the aid of elemental analysis and spectral methods including IR, 1H-NMR spectral data. The prepared compounds were evaluated for antibacterial activity against two Gram-positive bacteria (Staphylococcus aureus, Staphylococcus pyogenus), two Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli). The title compounds were also investigated for their antifungal activity using the broth micro dilution method. The bioassay results showed that compounds a few compounds showed good to superior in vitro antibacterial and antifungal activity.
EN
The effectiveness of the ammonia emission reduction from NBPT-stabilized urea was investigated in 2011 during a field experiment on a grassland plot fertilized with a one-time dose of 60 kg N/ha. The obtained reduction coefficient of ammonia emission equaled 73% and 39-51% relative to urea without the inhibitor and ammonium nitrate, respectively.
PL
W doświadczeniu polowym wykonanym późną wiosną w 2011 roku badano efektywność redukcji emisji amoniaku z mocznika stabilizowanego NBPT, który wykorzystywano do nawożenia użytków zielonych w jednorazowej dawce 60 kg N/ha. Uzyskany współczynnik redukcji emisji amoniaku w stosunku do mocznika bez inhibitora wynosił 73%, zaś w stosunku do saletry amonowej 39-51%.
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