• Journal of Sericultural and Entomological Science
• /
• v.20 no.1
• /
• pp.15-23
• /
• 1978

This studies have been carried out for several years to develop more better urea resin treating process on silk textiles which may be better crease resist without harming on the textile touch feeling. Specially, this paper payed attention to minimize the necessary formaldehyde content to be condensed with urea and created a new processing method which is named as Homo Metalic Urea Resin found to be better than urea resin process. The obtained results are as followings. 1. The prepared urea resin was found to be smell-less because of minimized formaldehyde content is the least than any other reports carried out before than this. 2. A new type of urea resin has been created by using uric 2incchloride and formaldehyde which is named as Homo Metalic Urea Resin. This processing method may carry both weighing process and urea resin process. 3. Crease resistance, stiffness and bulkiness were increased through such resin treats. Homo metalic urea resin process showed better results than the urea resin process. 4. Spun silk or low twisted silk have shown better crease resistance than raw silk or high twisted silk upon the both resin treats. 5. Both treat methods were found to be good economical feasibility upon the silk finishing process. 6. Tenacity and elongation of silk fibers were found to decrease some what because of grafting or weighing results. 7. Wooly silk has been also created with specific urea resin process. Such silk could be obtained by formaldehyde gas treat with urea soaken silk in a chamber, which induced to form scale on the surface of silk fibers.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.2
• /
• pp.211-215
• /
• 2001

Urea as a silage additive increases crude protein but reduces fermentation quality of silage by increasing pH and enhancing clostridial bacteria growth, especially in low sugar forages. Glucose and formic acid might be expected to compensate these defects caused by urea addition to grass silage. Thus, in this experiment urea formic acid or urea with glucose was applied to improve N content and the quality of napiergrass (Pennisetum purpureum Schumach.) silage. The first growth of napiergrass was harvested at 85 days of age and about 700 g of the grass was ensiled in laboratory silos (1.0 liter polyethylene containers) for 2, 7, 14, and 30 days at room temperature ($28^{\circ}C$). The treatments were no additives (control), urea, urea+glucose or urea+formic acid. Urea was added before ensiling at 0.5% of fresh weight of napiergrass and glucose and formic acid were added at 1% of fresh weight, respectively. After opening the silo, pH, dry matter content (DM), contents on DM basis of total N (TN), volatile basic nitrogen (VBN), lactic acid (LA), acetic acid (AA) and butyric acid (BA) were determined. The control at 30 days of fermentation showed 5.89 for pH with 13.8% for VBN/TN and 1.51% for AA. The addition of urea increased TN by about 1.5% units but decreased the fermentation quality by increasing pH from 5.89 to 6.86, increasing VBN/TN from 13.8% to 24.63%, increasing BA from 0.02% to 0.56%, and decreasing LA from 1.03% to 0.02%. Glucose addition with urea significantly decreased VBN/TN from 13.8% to 4.44% by reducing pH from 6.86 to 4.83 because of higher production of LA (2.62%). Adding urea and formic acid resulted in a more pronounced depression of VBN/TN and fermentation than the addition of urea and glucose. This study suggested that the combination of 1% glucose or 1% formic acid with 0.5% urea will improve nutritive value and fermentation quality of napiergrass silage.

• Analytical Science and Technology
• /
• v.18 no.4
• /
• pp.271-277
• /
• 2005

Urea in blood has been measured as an effective marker for diagnosis of renal function. Urea which is e end-product of nitrogen containing metabolites such as proteins is filtered through glomeruli of kidneys and then excreted as urine. If the renal function is deteriorated, the urea concentration in blood will be increased, from which the healthiness of renal function is judged. In order to improve the confidence of diagnosis results, the results must keep traceability chain to certified reference materials, which was certified by primary reference method. In this study, we proposed isotope dilution-liquid chromatography/mass spectrometry (ID-LC/MS) as a candidate primary method, in which $15^N_2$-urea is used as an internal reference material. The developed method is highly accurate in principle and is convenient as it does not require cumbersome derivatization. 0.1 mmol/L ammonium chloride was selected as a mobile phase for HPLC because it provided low interference in MS analysis of relatively low molecular weighted urea. HPLC and MS were connected with an electrospray ionization (ESI) interface of positive mode, which provided high sensitivity and reproducibility. The developed method was validated with internationally recognized reference materials, and we have obtained satisfactory results in an international ring trial. The expanded uncertainty calculated according to ISO guide was 1.8% at 95% confidence interval. The developed method is being used as a primary reference measurement method such as for certification of serum certified reference materials (CRMs).

• Asian-Australasian Journal of Animal Sciences
• /
• v.4 no.3
• /
• pp.235-240
• /
• 1991

A CRD experiment with thirty growing cross bred calves were assigned at random to three treatments rations. 1) $T_0$, 0% Urea + 20% M. O. cake, 2) $T_1$, 1% Urea + 10% M. O. cake and 3) $T_2$, 2% Urea + 0% M. O. cake to develop a rice straw based ration for ruminants. Sweetish odour and yellowish colour were observed in good recovered silage. Organic matter varied from 87.45% to 89.63% whereas crude protein varied from 14.0% to 14.5% in each treatment. No significant differences were found among the nutrient composition of the ration. The dry matter in take (DMI) and dry matter digestibility was higher in $T_0$ (0% Urea) than those of ration containing 1% ($T_1$) and 2% Urea ($T_2$). The organic matter digestibility decreases with increasing doses of urea. The crude protein & nitrogen-free-extract digestibility were found higher in the ration $T_1$ containing 1% urea whereas crude fibre digestibility and available metabolizable energy (ME) were higher in $T_0$ containing no urea as compared to $T_1$ and $T_2$. Total digestible nutrient (TDN) decreases with the increase of urea level. The highest feed efficiency was found in $T_0$ having no urea and lowest was in $T_2$. The animals gained in weights from each ration. Highest gain in weight was found in $T_0$ ration, then followed $T_1$, and $T_2$. This is due to natural protein available in M. O. cake only. It is concluded that supplemetation of urea or M. O. cake with readily available energy source as molasses upto 20% of total dietary dry matter in a complete ration may increase the intake of low quality fibrous roughage only when nitrogen and mineral are not limiting factor.

• Journal of the Korean Chemical Society
• /
• v.51 no.4
• /
• pp.339-345
• /
• 2007

Urea reacts with PtCl2, H2[PtCl6]·6H2O, H2[IrCl6] and Ni(CH3CO2)2 in aqueous solution at high temperature (60-80 °C) yielding [PtCl2(Urea)]·2H2O (1), (NH4)2[PtCl6] (2), (NH4)2[IrCl6]·H2O (3) and [Ni2(OH)2(NCO)2(H2O)2] (4) complexes, respectively. In complex 1, urea coordinates to Pt(II) as a neutral bidentate ligand via amido nitrogen atoms. In complexes 2, 3 and 4 it seems that the coordinated urea molecules decompose during the reaction at high temperature and a variety of reaction products are obtained. All complexes were isolated in moderate yields as dark green (1), yellow (2), pale brown (3) and faint green (4) precipitates, respectively. The reaction products were characterized by their microanalysis, IR, 1H and 13C NMR spectra as well as thermal analysis. General mechanisms describing the formation of these complexes were suggested.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.11
• /
• pp.999-1004
• /
• 2010

Recently, many technologies have been developed in order to satisfy stringent emission regulations. However, in the case of diesel engines, the stringent emission regulations with respect to NOx and PM have not yet been satisfied. A dramatic reduction in the NOx and PM emissions could be achieved by using after-treatment systems such as lean NOx trap (LNT) and urea-SCR systems. However, the high temperature in the exhaust pipe affects the spray behavior of the secondary injector, which is used for supplying the Urea-SCR. Because of this high temperature, it is difficult to achieve uniform distribution of the reducing agent in the manifold. In this paper, the characteristics of a urea-SCR injector used for injecting in the exhaust pipe are presented. The purpose of this study was to investigate the spray characteristics of the injector, such as the spray angle, injection quantity, and SMD. In addition, laser diagnostics and high-speed-camera images were used to analyze the injector spray characteristics and to present a distribution of reduction in the transparent manifold.

• 한국해양학회지
• /
• v.28 no.4
• /
• pp.323-331
• /
• 1993

The concentration-dependence of and the effect of light on urea decomposition, and the suppression of urea decomposition by ammonium were studied to understand adaptations in phytoplankton to utilization of urea in the estuarine system of the Mankyung and Dongjin rivers and a hypertrophied pond. Results of size-fractionation showed that bacterial fraction played a minor role (14%) in urea decomposition in the estuary. However, the role of bacteria in urea decomposition seemed to increase in a hypertrophic pond. Natural phytoplankton communities exhibited a monophonic or biphasic kinetics of urea decomposition over a wide range of concentration (upto 7.7 mM). the addition of high concentration of ammonium and incubation of the euphotic samples in the dark caused reductions in the urea decomposition rates. It is suggested that understanding of adaptations in phytoplankton to urea decomposition would help to study the temporal and spatial variabilities of urea decomposition rates in the field and the significance of urea in nitrogen cycle.

• 한국해양학회지
• /
• v.29 no.4
• /
• pp.402-413
• /
• 1994

To understand the significance of urea in the pool size of nitrogenous nutrients and in nitrogen (N) requirements of primary producers in and estuarine system of Mankyung and Dongjin rivers nutrients, and urea decomposition rates between June 1992 and February 1994. Urea concentration during the study period ranged from undetectable to 12.5 ug-at. N 1/SUP -1/, contributing to 0-96% (mean of 11%) of the total nitrogenous nutrients in the study area. Urea comprised a major component of the total nitrogenous nutrients when concentration of total nitrogenous nutrients was low. Urea decomposition rates in the water column ranged from 0.02 to 5.77 nM h/SUP -1/, and netplankton was the major decomposer of urea. Vertical distributions of urea decomposition rates in the water column showed generally small variabilities (i.e. < 3 fold). The decomposition rates of urea in the MD estuary would supply 0.2 ∼88.4% of phytoplankton N requirements. The major contribution of urea to phytoplankton N requirements was found when phytoplankton production was low (<50 mg C m/SUP -2/d/SUP -1/).

• Asian-Australasian Journal of Animal Sciences
• /
• v.7 no.3
• /
• pp.363-372
• /
• 1994

In two separate experiments with crossbred bulls (Sahiwal $\times$ indigenous) the effect of access to a urea-molasses lickblock (MOL-U-MIN) on straw diets was studied. The animals were given either untreated (US) or urea treated (TS) rice straw with or without lickblock supplementation. In experiment 1, individual dry matter intake (DMI) and dry matter digestibility (DMD) were measured, while in experiment 2 in addition to the above rumen (pH, ammonia, minerals) and blood (protein, minerals and haemotological) parameters were also measured. With both experiments urea treatment did not effect DMI, but lickblock supplementation significantly (p < 0.05) increased DMI. The DMD values obtained in both experiments for TS were significantly (p < 0.05) higher than for US, but lickblock supplementation did not effect the DMD of either US or TS fed animals. Both urea treatment (6.97 vs 6.93) and lickblock supplementation (6.98 vs 6.92) significantly (p < 0.001) reduced the rumen pH. Urea treatment and lickblock supplementation increased the rumcn $NH_3-N$ concentration (mg/100 ml) from 8.7 to 11.9 and 9.2 to 11.4, respectively. Both US and TS diets fed with or without lickblock increased the molar ratio of Na : K in saliva. Phosphorus content in blood plasma was significantly (p < 0.01) increased due to lickblock supplementation, whereas the Fc content in blood was significantly increased (p < 0.01) by urea treatment. Haemoglobin content in blood ranged from 11.3 to 11.7 g/dl, and was not influenced by urea treatment or lickblock supplementation. Lickblock significantly reduced the number of red blood cells, but increased the mean corpuscular volume. It is concluded that feeding urea treated straw with proper mineral supplementation could be a more economical alternative to lickblock supplementation.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.1
• /
• pp.26-30
• /
• 2006

The study was undertaken to investigate the validity of milk urea concentration as an index of the reproductive performances in crossbred Karan-Fries (Holstein Friesian${\times}$Tharparkar) cows under farm condition. Milk urea was analysed in noon milk samples (1200 to 1300 h) to interrelate with the interval from parturition to first service, number of insemination per conception, first service conception rate and service period. Milk progesterone (P4) was analysed in noon milk samples on the day 1, 10, 20 and 30 post insemination to study the effect of milk urea concentration on early embryonic mortality. The interval from parturition to first service was found significantly (p<0.01) higher ($77.2{\pm}5.5$ days) when milk urea concentration was ${\geq}63.4mg/dl$. The average milk urea concentrations (mg/dl) were found $42.1{\pm}2.5$, $47.9{\pm}1.5$ and $50.3{\pm}3.1$, respectively in cows that conceived at $1^{st}$, $2^{nd}$ and $3^{rd}$ insemination. However, the variation was not statistically significant. The first insemination conception rate was found significantly (p<0.05) higher (68.8%) when milk urea level was ${\leq}32.4mg/dl$. The service period was found significantly (p<0.05) higher ($125.4{\pm}8.8$ days) when milk urea concentration was ${\geq}45.1mg/dl$. The milk P4 level indicated that the cows, those were detected as non-pregnant on day 60 post insemination were initially pregnant but the pregnancy was terminated sometime during the day 30 to 60 post insemination. The study indicates that the milk urea values may be used as an index of reproductive performances in dairy herd when individual animals are not being monitored for nutritional status. The altered milk urea values may be utilised by the farmers as ready reference to rectify the protein and energy nutrition in cows to achieve the better reproductive performances in herd.