Effects of cobalt-60 γ-ray irradiation on fresh-keeping and storage of kiwifruits

The boxes contained kiwifruits were irradiated with cobalt-60 γ-rays at different dosages (0.6 , 1.8 and 3.6 KGy) and stored in a room ventilated at night, the natural ambient air being used as cool source.The results showed that the treatment which fruits irradiated with 0.6 KGy was the best after 85 days. It gave the normal-fruit rate of 95.10%, fruit flesh hardness of 4.10 Kg · cm^-2, fresh and plump fruits, good quality and less Vc loss.     

Electrode kinetics of Eu3+/Eu2+ reaction by cyclic voltammetry

The cyclic voltammetric behaviour of Eu³⁺/Eu²⁺ couple at hanging mercury drop electrode (HMDE) has been studied in chloride, bromide, iodide, thiocyanate and EDTA supporting electrolytes. The apparent rate constant and transfer coefficient for these systems have been calculated at various voltage scan rates, without using the data for standard or formal potential. The values have been compared with those obtained by earlier workers through other electrochemical methods.     

Momentum transfer in an agitated vessel with off-centred impellers

Momentum transfer was investigated in an unbaffled agitated vessel of inner diameter 0.3 m equipped with different off-centred impellers. The distribution of the shear rate on the tank wall as a function of the impeller type and Reynolds number was studied in the turbulent regime of the Newtonian liquid flow. The dependences of the averaged dimensionless shear rate, friction coefficient, and dissipated energy on the Reynolds number and eccentricity ratio were approximated using four-parameter equations. Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May 2006.     

Stochastic simulation of reactive separations in capillary electrophoresis

A stochastic (Monte Carlo) simulation is used to investigate thermodynamic and kinetic contributions from the reversible A <--> B reaction in capillary electrophoresis (CE). The effects of equilibrium constant, rate constant, and electrophoretic mobility on the molecular zone profiles and the corresponding statistical moments are evaluated. As the reaction approaches steady state, the velocity of the zone is governed by the equilibrium constant and the electrophoretic mobilities of the reacting molecules. When the equilibrium constant is less than unity, the mean zone velocity is more similar to that of the reactant A. Conversely, when the equilibrium constant is greater than unity, the velocity is more similar to that of the product B. The extent of zone-broadening and asymmetry at steady state is dependent upon the equilibrium constant, the characteristic reaction lifetime, and the electrophoretic mobility difference between reacting molecules. If all other parameters are held constant, the plate height is greatest and skew is least when the equilibrium constant is unity. The plate height increases linearly with the characteristic reaction lifetime and electrophoretic mobility difference, whereas the skew is independent of these parameters. These conclusions have important implications for the elucidation of thermodynamic and kinetic information from experimental data.     

Gas chromatographic method for studying the rate of photodegradation of some nitrogen-containing pesticides

Summary The photodegradation behaviour of 12 nitrogen-containing herbicides (atrazine, cyanazine, terbuthylazine, terbutryn, EPTC, buthylate, molinate, cycloate, vernolate, fenuron, chloroxuron, and methabenzthiazuron) has been examined. The compounds were degraded completely when exposed to a mercury-vapour lamp; the degradation process was followed by consecutive GC measurements. All the compounds studied had measurable photochemical activity, although actual and average degradation rates varied significantly. All the compounds except terbutryn furnished more than one major degradation product, in different ratios. Presented at Balaton Symposium '01 on High-Performance Separation Methods, Siófok, Hungary, September 2–4, 2001     

Kinetic parameters of unsaturated polyester resin modified with poly(ε -caprolactone)

The mineral sabugalite (HAl)_0.5[(UO₂)₂(PO₄)]₂⋅8H₂O, has been studied using a combination of energy dispersive X-ray analysis, X-ray diffraction, dynamic and controlled rate thermal analysis techniques. X-ray diffraction shows that the starting material in the thermal decomposition is sabugalite and the product of the thermal treatment is a mixture of aluminium and uranyl phosphates. Four mass loss steps are observed for the dehydration of sabugalite at 48°C (temperature range 39 to 59°C), 84°C (temperature range 59 to 109°C), 127°C (temperature range 109 to 165°C) and around 270°C (temperature range 175 to 525°C) with mass losses of 2.8, 6.5, 2.3 and 4.4%, respectively, making a total mass loss of water of 16.0%. In the CRTA experiment mass loss stages were found at 60, 97, 140 and 270°C which correspond to four dehydration steps involving the loss of 2, 6, 6 and 2 moles of water. These mass losses result in the formation of four phases namely meta(I)sabugalite, meta(II)sabugalite, meta(III)sabugalite and finally uranyl phosphate and alumina phosphates. The use of a combination of dynamic and controlled rate thermal analysis techniques enabled a definitive study of the thermal decomposition of sabugalite. While the temperature ranges and the mass losses vary due to the different experimental conditions, the results of the CRTA analysis should be considered as standard data due to the quasi-equilibrium nature of the thermal decomposition process. The online version of the original article can be found at     

Pyrolysis and TG Analysis of Shivee Ovoo Coal from Mongolia

The coal sample of the Shivee Ovoo deposits has been non-isothermally pyrolysed in a thermogravimetric analyser to determine the influence of temperature, heating rate and purge gas employed on the thermal degradation of the sample. The heating rates investigated in the TG were 10–50 K min^–1 to final temperature of 1000°C. N₂or CO₂ were employed as well as type of purge gas on the process of thermal degradation of the coal sample. The coal was also investigated in a fixed bed reactor to determine the influence of temperature and heating rate of the pyrolysis on the yield of products and composition of the gases evolved. The main gases produced were H₂, CH₄, C₂H₂, C₂H₄, C₂H₆, C₃H₆ and C₃H₈ and also minor concentrations of other gases. This revised version was published online in August 2006 with corrections to the Cover Date.     

原油乳状液破乳的动态法研究

The stability of different crude oil emulsions from ASP flooding production well is studied by the method of a stirred tank. The demulsifying of crude-oil emulsion by different demulsifying agents is discussed. The breakage of the crude oil emulsions from the well PO11 by the different types and concentrations of the emulsifying agents is also discussed. The breaking mechanism of the demulsifying agent is described microscopically.     

对硅酸聚合机制反应级数的验证

用胶凝法研究酸化了的不同摩尔比 (Si O2 /Na2 O)的硅酸钠溶液的胶凝速度 ,发现在恒盐条件下 ,硅酸胶凝速度常数是 2 ,这个结果和我们过去所提出的硅酸聚合机制符合一致。     

氯化聚乙烯对甲基丙烯酸甲酯／苯乙烯共聚动力学的影响

将甲基丙烯酸甲酯（ＭＭＡ）／苯乙烯（Ｓ）在氯化聚乙烯（ＣＰＥ）存在下进行悬浮溶胀接枝共聚，考察了ＣＰＥ对ＭＭＡ／Ｓ共聚动力学行为的影响．ＣＰＥ提高了聚合体系的粘度，使自动加速提前，扩散因素增加，对共聚有阻滞作用．ＣＰＥ是链转移剂，使ＭＭＡ／Ｓ共聚物分子量降低．ＣＰＥ对ＭＭＡ的吸附渗透优于对Ｓ的吸附，造成接技部分与非接技部分组成的差异．ＣＰＥ含量、溶胀时间、转化率、硫酸用量对共聚组成均有影响。