In Laos, smallholder cattle farmers rely primarily on natural grassland grazing, which needs to be improved for fattening. Notably, most cattle prices are determined by the middleman, by looking, so buyers tend to undervalue their price, which makes cattle farming a minimal investment. Urea-Molasses Block (UMB) supplements can effectively enhance a nutrient diet in low-quality roughage systems. This study aimed to determine factors affecting UMB and farmers’ Willing To Pay (WTP) for UMB as a new input material with data from six villages, two districts of the Vientiane Capital, in January and July 2019. The results indicate that farmers with relatively high education, consent to the positive effect of UMB, and previous experience purchasing feed during the dry season are more likely to pay a high positive WTP. The average WTP for UMB ranges from USD 5.7 to 6.5 per month for one cattle, which is approximately 10.2~11.6% of current annual costs for average smallholder cattle farmers. These findings will be significant in improving productivity at the initial development stage of farms in Laos, especially for smallholder farmers.

This work reported the electrochemical and photoelectrochemical (PEC) properties of a new photoelectrode based on hematite Co-Fe2O3@NiO, a photoactive semiconductor, was prepared using a process involving a combination of the co-precipitation and microwave-assisted synthesis of Fe2O3, Co-Fe2O3 and Co-Fe2O3@NiO, respectively. The obtained products were characterized by X-Ray powder Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray analysis (EDX), Ultraviolet–Visible (UV–vis) analysis, Fourier Transform Infrared spectroscopy (FT-IR). X-ray diffraction (XRD) pattern of the sample determined the crystal structure of α-Fe2O3 nanoparticles. The SEM image shows spherical nanoparticles. FTIR spectrospy spectrum confirmed the phase purity and chemical bond for the sample. Optical studies show a variation of band gap from 2.118 to 2.07 eV. The electrochemical and photoelectrochemical (PEC) performance of the films were examined by cyclic voltammetry, linear sweep voltammetry and chronoamperometry. The electrochemical oxidation of water achieved by Cobalt-doped Fe2O3@ GCE modified electrode exhibited the current density of 21 mA/g at 0.5 V vs. SCE for 5 at% of Co and reveals enhanced specific capacitance of 352.11 F/g. The catalytic performance of urea oxidation was measured by cyclic voltammetry on Co-Fe2O3@NiO nanoparticles modified glassy carbon electrode (GCE) in alkaline medium. The electrode Co-Fe2O3@NiO without annealing showed a peak current density of 1.59 mA/cm2 at 0.1 M urea in 1.0 M NaOH, which was 3.6 fold higher than that of Co-Fe2O3@NiO with annealing. In another part, this work reported the photoelectrochemical (PEC) properties of photoanode prepared by spin coating. The highest photocurrent 0.042 mA/cm2 at 0.5 V Vs SCE was obtained for 5% Co-Fe2O3@NiO while the photocatalytic oxidation of urea.

이소시아네이트와 아민의 빠른 반응성으로 인해 고가의 전용 도포 설비가 있어야만 시공이 가능하였던 우레아 수지를, 일반적인 도포 설비로도 시공이 가능하도록 수분산 상태의 우레아 수지를 합성하기 위한 조건을 설정하기 위하여, 1차적으로 분자량과 관능기의 수가 다른 폴리이서 아민과 다이이 소시아네이트를 사용하여 기계적 물성이 우수한 수분산 우레아 수지 합성 조건을 찾고, 2차적으로 DMPA [2,2-Bis(hydroxymethyl)propanoic acid]의 함량이 수분산 우레아 수지의 수분산 안정성에 미치는 영향을 연구하였다. 우레아기의 형성은 FT-IR ATR 분광법으로 확인하였다. 그 결과 수분산 우레아 수지의 기계적 물성은 분자량과 관능기수가 다른 폴리이서 디아민과 폴리이서 트리아민을 함께 투입한 PU-4와 PU-6 배합의 경우, 각각 인장강도가 10.5 N/㎟, 12.7 N/㎟ 및 신장률이 1165 %, 969 %로 우수하였다. 또한, 인장강도가 가장 높은 PU-6 배합에 DMPA을 0.5 몰 첨가하여 합성한 후 트리에틸 아민으로 중화시킨 수분산 우레아 수지가 14.2 N/㎟의 인장강도와 993 %의 신율로 가장 우수하였으며, 8 주 동안의 저장안전성 평가에서도 수분산 상태가 가장 안정하게 유지되었다.

대기오염에 대한 관심이 증대하면서 대기오염물질의 저감에 관한 많은 연구가 진행되고 있다. 차량용 요소수(Urea solution)를 이용한 디젤 차량의 질소산화물(NOx) 제거는 큰 효과를 나타내고 있다. 요소수의 품질은 국내법으로 엄격히 규정하고 있으나 요소수 내 불순물의 증대는 질소산화물 저감 효과를 감소시키게 된다. 따라서 본 연구에서는 일정 온도와 시간동안 요소수를 가열한 후 요소수의 물성변화를 분석하였다. 또한, 요소수를 보관하는 저장용기와 저장온도의 변화에 따른 요소수 물성변화도 함께 분석하였다. 요소수를 일정시간 가열한 후 요소수 내 뷰렛함량은 증가하고 요소함량은 감소하였으며, 요소함량 감소에 따라 밀도와 굴절률도 함께 감소하였다. 철제 및 PET 용기와 일정온도(30 ℃, 50℃)에서 실시한 저장안정성 시험에서는 물성변화가 나타나지 않았다.

This manuscript explains the effective determination of urea by redox cyclic voltammetric analysis, for which a modified polypyrrole-graphene oxide (PPY-GO, GO 20% w/w of PPY) nanocomposite electrode was developed. Cyclic voltammetry measurements revealed an effective electron transfer in 0.1 M KOH electrolytic solution in the potential window range of 0 to 0.6 V. This PPY-GO modified electrode exhibited a moderate electrocatalytic effect towards urea oxidation, thereby allowing its determination in an electrolytic solution. The linear dependence of the current vs. urea concentration was reached using square-wave voltammetry in the concentration range of urea between 0.5 to 3.0 μM with a relatively low limit of detection of 0.27 μM. The scanning electron microscopy was used to characterize the morphologies and properties of the nanocomposite layer, along with Fourier transform infrared spectroscopy. The results indicated that the nanocomposite film modified electrode exhibited a synergistic effect, including high conductivity, a fast electron-transfer rate, and an inherent catalytic ability.

본 연구에서는 질소산화물 제거용 환원제로 사용하는 요소 수용액을 암모니아로 전환하는데 있어 SCR 상용촉매의 활용가능성을 확인하기위해 촉매조성에 따른 반응온도, 공간속도의 영향에 대한 연구를 수행하였다. 연구결과 SCR 촉매로 널리 사용되는 V2O5/TiO2 촉매는 TiO2 및 WO3-V2O5/TiO2 촉매에 비해 암모니아 생성이 우수함을 보였다. 활성금속을 담지하지 않은 TiO2 촉매는 V2O5 혹은 WO3-V2O5를 담지 한 촉매에 비해 공간속도에 따른 암모니아 전환에 영향을 받지 않는 것으로 나타났으며, 활성금속을 담지 한 촉매는 공간속도가 증가함에 따라 암모니아 생성 농도가 감소됨을 확인하였다.

Nitrogen-atom doped graphene oxide was considered to prevent the dissolution of polysulfide and to guarantee the enhanced redox reaction of sulfur for good cycle performance of lithium sulfur cells. In this study, we used urea as a nitrogen source due to its low cost and easy preparation. To find the optimum urea content, we tested three different ratios of urea to graphene oxide. The morphology of the composites was examined by field emission scanning electron microscope. Functional groups and bonding characterization were measured by X-ray photoelectron spectroscopy. Electrochemical properties were characterized by cyclic voltammetry in an organic electrolyte solution. Compared with thermally reduced graphene/sulfur (S) composite, nitrogen-doped graphene/S composites showed higher electroactivity and more stable capacity retention.

This study used transmission electron microscopy (TEM) to investigate the micro-morphological features of two formaldehyde to urea (F/U) mole ratio liquid urea-formaldehyde (UF) resins with three hardener levels as a function of the curing time. The micro-morphological features of the liquid UF resins were characterized after different curing times. As a result, the TEM examination revealed the presence of globular/nodular structures in both liquid UF resins, while spherical particles were only visible in the low F/U mole ratio resins. The high F/U mole ratio liquid UF resins also showed extensive particle coalescence after adding the hardener, along with the appearance of complex filamentous networks. When the resins were cured with a higher amount of hardener and longer curing time, the spherical particles disappeared. For the low mole UF resins, the particles tended to coalesce with a higher amount of hardener and longer curing time, although discrete spherical particles were still observed in some regions. This is the first report on the distinct features of the crystal structures in low F/U mole ratio UF resins cured with 5% hardener and after 0.5 h of curing time. In conclusion, the present results indicate that the crystal structures of low F/U mole ratio UF resins are formed during the curing process.

바이오디젤의 저온유동성과 산화안정성은 주로 녹는점이 높은 포화 및 불포화 지방산 메틸에스테르의 함량에 의해 좌우된다. 본 연구는 동물성 유지인 우지 유래 바이오디젤에 요소를 첨가하여 포화지방산 메틸에스테르 함량을 저감시켜 동물성 바이오디젤의 저온유동성 개선과 포화지방산 메틸에스테르 함량이 저감된 동물성 바이오디젤을 식물성 바이오디젤에 혼합함으로써 식물성 바이오디젤(유채유, 폐식용유, 대두유 및 동백유)의 저온유동성을 개선하기 위해 수행 되었다. 연구결과, 동물성 바이오디젤의 포화도 저감을 통해 저온필터막힘점을 최대 –15℃까지 낮추었고, 포화도가 저감된 동물성 바이오디젤을 식물성 바이오디젤과 혼합함으로서 식물성 바이오디젤의 저온필터막힘점을 -10 ~ -18℃까지 낮출 수 있었다. 본 연구를 통해 동·식물성 유지 유래 바이오디젤의 저온특성을 개선함으로써 국내 겨울철 환경조건에서 연료유로 적용 가능성을 증대할 것으로 기대한다.

As a part of abating formaldehyde emission of urea-formaldehyde resin, this study was conducted to investigate the rmalcure kinetics of both neat and modified urea-formaldehyde resins using differential scanning calorimetry. Neat urea-formaldehyde resins with three different formaldehyde/urea mol ratios (1.4, 1.2 and 1.0) were modified by adding three different additives (sodium bisulfite, sodium hydrosulfite and acrylamide) at two different levels (1 and 3wt%). An isoconversional method at four different heating rates was employed to characterize thermal cure kinetics of these urea-formaldehyde resins to obtain activation energy () dependent on the degree of conversion (). The values of neat urea-formaldehyde resins (formaldehyde/urea = 1.4 and 1.2) consistently changed as the increased. Neat and modified urea-formaldehyde resins of these two F/U mol ratios did show a decrease of the at the final stage of the conversion while the of neat urea-formaldehyde resin (formaldehyde/urea = 1.0) increased as the increased, indicating the presence of incomplete cure. However, the change of the values of all urea-formaldehyde resins was consistent to that of the Ea values. The isoconversional method indicated that thermal cure kinetics of neat and modified urea-formaldehyde resins showed a strong dependence on the resin viscosity as well as diffusion control reaction at the final stage of the conversion.

The objective of this study was to investigate the relationship between concentration of urea nitrogen, glucose, cholesterol and number of transferable embryos for the purpose of improving reproductive performance in blood of Hanwoo donors. Fifty five, at random stages of the estrous cycle, received a CIDR. Four days later, the animals were superovulated with a total of 28AU FSH (Antorin, 2AU=1 ml) administered twice daily in constant doses over 4 days. On the 3th administration of FSH, CIDR was withdrawn and 25 mg PGF2α was administered. Cows were artificially inseminated twice after estrous detection at 12 hr intervals. The cows received 100μg GnRH at the time of 1nd insemination. Embryos were recovered 7 or 8 days after the 1st insemination. Cows with BUN ＜10, 11～18 and ≥19 mg/dl had number of transferable embryos of 4.3±1.3, 5.8±1.8 and 4.7±2.1 respectively. The mean numbers of total ova from < 10 and 10≤ of corpora lutea(CL) was 8.9 and 14.3, respectively. The number of transferable embryos differed between < 10 and 10≤ CL was 4.8 and 5.6, respectively.

The industrial manufacturing of YSZ products can be summarized as a three step process: a) hydrolysis of zirconyl chloride and mixing of other solutions, b) precipitation, and c) calcination. The addition of ammonia or OH- is essential in the precipitation process. However, a strong agglomeration was observed in the results of an ammonia or OH- addition. Thus, it is necessary to disperse the powders smoothly in order to improve the mechanical strength of YSZ. In this study, YSZ was synthesized using the urea stabilizer and hydrothermal method. YSZ powders were synthesized using a hydrothermal method with Teflon Vessels at 180˚C for 24 h. The mole ratio of urea to Zr was 0, 0.5, 1, and 2. The crystal phase, particle size, and morphologies were analyzed. Rectangular specimens (33 mm×8 mm×1±0.5 mm) for three-point bend tests were used in the mechanical properties evaluation. The crystalline of YSZ powders observed a tetragonal phase in the sample with a ratio of Zr:urea = 1:2 addition and a hydrothermal reaction time of 24 h. The average primary particle size of YSZ was measured to be 9 nm to 11 nm. The agglomerated particle size was measured from 15 nm to 30 nm. The three-point bending strength of the YSZ samples was 142.47 MPa, which is the highest value obtained for the Zr:urea = 1:2 ratio addition YSZ sample.

Addition of ammonia or any nitrogenous materials to the soil that release ammonia causing alkaline condition during decomposition stimulates the fruiting of a particular chemoecological group of fungi, called ammonia fungi (Sagara 1975). The study of ammonia fungi by artificial application of urea in forest soil has been done in diverse geographical regions such as in Japan, Taiwan, New Zealand, Western Australia, and UK. Up to date about 70 species of ammonia fungi have been recorded in those regions. However, ammonia fungi in the boreal forest of American continent have not yet been investigated. Thus, we collected the soils of A0 and the upper layer of HA horizons in plant pots from aspen forest near Edmonton, Canada. Thereafter, we applied urea (granular fertilizer; 46% nitrogen, 10 mg/g dry soil) in plant pots and incubated at 25˚C under 12 hours dark and light regime. After 40 days of incubation, several basidiomata of Coprinopsis species appeared. Among them one specimen was identified as C. rugosobispora based on macro- and microscopic features. Morphologically this species was very similar to C. phlyctidospora which was characterized by warty, ovoid basidiospores, and diverticulate veil elements. C. phlyctidospora has 4-spored basidia while C. rugosobispora had only 2-spored. In the beginning, it was thought probably it was only a 2-spored form of C. phlyctidospora. The basidiospore of C. rugosobispora (9.8-11.7×8.3-9.6㎛) was distinctly larger than that of C. phlyctidospora (8.4-10.6×6.0-7.6 ㎛). It was therefore separated from the C. phlyctidospora. Furthermore in this study we investigated its phylogenetic relationship based on the nuclear rDNA sequence in ITS regions and mating reactions among its close allies and further confirmed it as a distinct species. This is the first record of C. rugosobispora from American continent since it has been collected only from Europe (Belgium and Netherlands). Although urea effectively stimulated its occurrence but it has not yet been reported any other urea application studies so far. This indicates it is a new record in ammonia fungi as well.

The objective of this study was investigate the superovulation treatment and to relate concentrations of blood urea nitrogen(BUN) in Hanwoo donors. Thirty six, at random stages of the estrous cycle, received a CIDR. Four days later, the animals were superovulated with a total of 28AU FSH (Antorin, 2AU=1 ml) administered twice daily in constant doses over 4 days. On the 3th administration of FSH, CIDR was withdrawn and 25 mg PGF2α was administered. Cows were artificially inseminated twice after estrous detection at 12 hr intervals. The cows received 100 μg GnRH at the time of 1st insemination. Embryos were recovered 7 or 8 days after the 1st insemination. Cows with BUN ＜10, 11～18 and ≥19 mg/dl had return of estrus of 34.6, 30.5 and 30.4 days respectively. Return of estrus after superovulation treatment was not significantly lower for cows with blood urea nitrogen (BUN) above 10 mg/dl than for cows with BUN below 10 mg/dl. Cows with BUN ＜10, 11～18 and ≥19 mg/dl had number of transferable embryos of 3.2±1.2, 5.4±1.9 and 4.1±2.1 respectively.