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61.
Sugarcane can be very susceptible to damage by freezes. Freeze-deteriorated cane can cause problems in processing and sometimes leads to a factory shut-down. This study was undertaken during the 2000/2001 harvest season to assess the cold tolerance performance of six commercial sugarcane varieties and to establish new and more sensitive criteria to measure cold tolerance. Two varieties CP 70-321 and CP 79-318, with known cold tolerance, were planted in the study as controls. The other varieties included LHo 83-153, LCP 85-384, HoCP 85-845 and HoCP 91-555. Freezing temperatures occurred on 20 December 2000 when the min. field temperature was −4.4 °C, and again on 21 December, 30 December through 5 January 2001, 9–10 January and 20–21 January. The lowest field temperature recorded was −5.6 °C on 4 January. Freezing conditions prevailed for 8–15 h during each freeze incident. Stalks of all varieties were frozen to the ground following the initial freeze, with freeze cracks evident only after the 4 January freeze. For this study, samples were taken on the date of the first freeze, 20 December, and subsequently again at 7, 14, 22 and 30 days after the first freeze. Criteria used to measure overall stalk cold-tolerance included changes in pH, Brix, dextran (ASI-II method), sucrose, glucose, and fructose concentrations. Mannitol, ethanol and the oligosaccharides, palatinose, leucrose, iso-maltotriose and 1-kestose, were simultaneuously measured using IC-IPAD. Marked differences were observed in most criteria for all varieties, particularly 22 and 30 days after the first freeze. Mannitol was strongly correlated (r2=0.84) with dextran, confirming its use as an indicator for cane dextran deterioration. In comparison, ethanol was only weakly correlated (r2=0.55) with dextran and did not always predict cane dextran deterioration. Iso maltotriose was the most sensitive oligosaccharide indicator of freeze deterioration, although both leucrose and palatinose could be used to confirm whether severe dextran formation (>1500 ppm/Brix) has occurred in cane. Isomaltotriose was strongly correlated (r2=0.89) with dextran and pH (r2=−0.83); pH was also a strong indicator of both dextran (r2=−0.85) and mannitol (r2=−0.92) formation. Four of the varieties, CP 79-318, LCP 85-384, HoCP 85-845 and HoCP 91-555, were shown to be susceptible to other sources of microbial and enzymic deterioration as well as dextran deterioration from Leuconostoc bacteria, especially 30 days after the first freeze. This was indicated by increased glucose/fructose ratios, ethanol formation, changes in 1-kestose concentration, and further sucrose losses. 相似文献
62.
针对梁南结垢的具体情况,探讨了输油管线结硫酸盐垢的原因及影响因素,指出了化学防垢的可行性。室内成功研制出DY-2阻垢剂,现场应用后有效地预防了硫酸钡、锶垢的形成。 相似文献
63.
The impinging streams technology (abbreviated as IS) has good micromixing in the precipitation processes. The experiments were loaded with two reactants, BaCl2 and Na2SO4, to prepare BaSO4 in the impinging streams reactor, comparing with those in the direct precipitation (DP) reactor. XRD and TEM were used to analyze the crystal type, the morphology and size of particles through the photographs. The results indicate the size of the particles from IS is about 30 nm and of narrower distribution and finer dispersibility than that from DP. 相似文献
64.
Jantana Tangaromsuk Abhijeet P. Borole Maleeya Kruatrachue Prayad Pokethitiyook 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(10):1375-1380
BACKGROUND: A single‐stage reactor, in which the growth of bacterial culture, induction of desulfurizing enzymes, and desulfurization reaction are carried out in a single step, was adopted to investigate desulfurization of dibenzothiophene (DBT) at high cell densities. Rhodococcus erythropolis, IGTS8 was used as the biocatalyst. Optimal conditions for bacterial growth and DBT desulfurization were investigated. RESULTS: Optimization of fermentation conditions was necessary to obtain high cell densities including controlling accumulation of acetate. Under optimal operating conditions, the maximum optical density at 600 nm (OD600) was measured to be 26.6 at 118 h of cultivation. When biodesulfurization of DBT in model oil with a high cell density culture of IGTS8 was investigated, accumulation of sulfate was found to limit the extent of desulfurization. A sulfate removal step was added to obtain a single‐stage integrated biodesulfurization process. Sulfate removal was achieved via an aqueous bleed stream and use of a separation unit to recycle the organic phase. CONCLUSION: A proof of principle of a complete system capable of biocatalyst growth, induction, desulfurization and by‐product separation was demonstrated. This system enables simplification of the biodesulfurization process and has potential to lower the operating cost of the bioprocess. Copyright © 2008 Society of Chemical Industry 相似文献
65.
用二氧化硫法处理贫软锰矿,得到含硫酸锰和连二硫酸锰的溶液,继而将该溶液进行净化,除杂,浓缩,结晶处理即得工业级硫酸锰,结晶母液用碳铵沉淀即得碳酸锰产品 相似文献
66.
介绍了中国铝业贵州分公司在能源统计和管理、节能技术改造、资源综合利用和清洁生产方面所采取的措施和取得的效果。 相似文献
67.
A decay of fresh-cut celery (Apium graveolens) segments stored at < 5°C in sealed film bags began with a water soaking of the cut surfaces. Slimy moisture accumulated inside the bags. The segments water soaked completely, softened, discolored and sometimes disintegrated. Total aerobic bacterial populations isolated from decayed segments ranged from log10 7.0–7.7 CFU/g tissue weight. The predominant bacteria, identified by fatty acid analysis as Pseudomonas fluorescens and P. marginalis, caused water soaking, soft rot, and discoloration in freshly inoculated celery tissues stored at 5 or 25°C. Leuconostoc mesenteroides was also isolated and may have been responsible for slime production. 相似文献
68.
The mechanisms governing the solubilizing interactions between zwitterionic/anionic mixed surfactant systems at different
molar fractions of the zwitterionic surfactant (Xzwitter) and neutral or electrically charged unilamellar liposomes were investigated. The mixed systems were formed by N-dodecyl-N,N-dimethylbetaine
and sodium dodecyl sulfate in the presence of piperazine-1,4-bis-(2-ethanesulfonic acid) buffer at pH 7.20. Unilamellar liposomes formed by egg phosphatidylcholine, in some cases together
with stearylamine or phosphatidic acid, were used. Solubilization was detected as a decrease in static light-scattering of
liposomes. Two parameters were regarded as corresponding to the effective surfactant/lipid molar ratios (Re) at which the
surfactant system (i) saturated the liposomes, Resat, and (ii) led to a total solubilization of liposomes, Resol. From these parameters the bilayer/aqueous medium surfactant partition coefficients for the saturation (Ksat) and complete bilayer solubilization (Ksol) were determined. When Xzwitter was 0.40, The Re and K parameters showed a maximum, whereas the critical micellar concentration (CMC) of these systems exhibited
a minimum, regardless of the electrical charge of bilayers. Given that the ability of the surfactant systems to saturate or
solubilize liposomes is inversely related to the Resat and Resol parameters, these capacities appear to be directly correlated with the CMC of the mixed systems. The similarity of both Ksat and Ksol (particularly for Xzwitter=0.2–0.8) suggests that a similar partition equilibrium governs both the saturation and the complete solubilization of bilayers,
the free surfactant concentration (Sa,Sb), remaining almost constant with similar values to the CMC for each mixed system studied. 相似文献
69.
Fifty samples each of two leading brands of French, non-carbonated (‘still’) mineral waters, packed in plastic bottles, were stored in the dark for one month at approximately 20°C to allow marked proliferation of their autotrophic microbial flora. Upon completion of this challenge test 1250 ml per bottle were filtered through five membranes, which were subsequently cultured on 1/10 strength nutrient agar for 48 h at a temperature favouring the growth of thermotrophic organisms only, i.e. 42 ± 0.5°C. The numbers of colonies per one litre were below 103 in all samples and did not exceed 200 in 56–80%, depending on the brand. Identification of the isolates demonstrated strong inhibition of the psychrotrophic. Gram-negative types, predominating in the association flora of stored still waters and preponderance of Gram-positive, catalase-positive, facultatively anaerobic cocci. Consequently, a Reference Value for the thermotrophic autotrophic colony count per 1 ml in still, commercial mineral waters of the order m = 1 and M = 5 seems justified. It is emphasized that, besides examining for these trivial organism, the usual tests for marker bacteria (Escherichia coli and Lancefield group D streptococci) and Pseudomonas aeruginosa should always be carried out. 相似文献
70.