On the fatigue behaviour of quenched and tempered at 300 and 600 °C SAE 1045 steel in an environment of sugar cane juice

SAE 1045 steel is widely used for manufacturing shafts in the sugar cane mills of the sugar industry. These shafts are designed with an expectation of a long lifetime. However, fatigue failures occur frequently. The sugar cane juice processed in these mills has corrosive properties that can alter the fatigue life of these shafts. In this research, the fatigue strength of SAE 1045 steel between 1 × 10⁴ and 2 × 10⁵ cycles in air and in sugar cane juice, with two different microstructures (tempered martensite at 300 °C and tempered martensite at 600 °C), was determined in rotating bending. The microstructure of the materials was characterized using optical microscopy, and the fracture surfaces were characterized using scanning electron microscopy. The results show that the fatigue strength at 2 × 10⁵ cycles for the tempered condition at 600 °C decreases 7% because of the sugar cane juice effect, and for the tempered condition at 300 °C, the fatigue strength decreases 15%.     

甘蔗汁火锅底料的研制

将甘蔗汁加入火锅底料中既保留原火锅的风味又对人体的脾胃进行调理，使脾胃虚弱的人可以在饱口福的同时不必担心文进武出。此次主要阐述在既保留火锅风味又对脾胃进行调理甘蔗汁的最佳添加量，同时也对工业化生产火锅底料的配方、工艺、保存方法进行了讨论。     

蔗汁酒精发酵中酵母菌株筛选及发酵工艺优化

以甘蔗汁为培养基比较CICC1308、As2．1190、广西贵糖4608、As2．109（GIM2．34）和R12（GIM2．84）五株酿酒酵母的酒精发酵特性。通过酒精耐受性及发酵能力测试，选出适合蔗汁酒精发酵的菌株为CICC1308。通过CICC1308菌株发酵工艺的单因素试验对发酵液原始pH值、发酵温度、接种量及发酵时间进行优化。结果表明：发酵液原始pH值5．0、发酵温度30~C、接种量15％（v／v）和发酵时间60h为最优条件试验，酒精产率可达92．15％。     

Assessment of variables effects on sugar cane juice clarification by carbonation process

This paper reports a study of sugar cane juice carbonation and the evaluation of variables effects such as pH, carbonation time and temperature on industrially relevant parameters for the quality of sugar cane juice. Three different batches of sugar cane juice were evaluated using a complete two‐level factorial design with central point performed in triplicate. From results in this work, it can be seen that the higher sucrose concentrations and lower percentage of total soluble solids and reducing sugars were obtained in clarified juices with the maximum values for pH, time and reaction temperature (9.5, 60 min and 80 °C). The temperature favoured the removal of starch, phosphate and turbidity. Colour removal reached a maximum of 88–93% among the batches. The optimum clarification condition using carbonation procedure can be achieved between 20 and 40 min, at pH values between 8.0 and 9.5 and temperature condition at 80 °C.     

Effects of tangential microfiltration and pasteurisation on the rheological,microbiological, physico‐chemical and sensory characteristics of sugar cane juice

The aim of this study was to determine the physico‐chemical, microbiological, rheological and sensory characteristics of sugar cane juice with passion fruit pulp (5% w/w) added and which had been submitted to microfiltration and pasteurisation (90 °C/30 s; 95 °C/30 s) processes. The results showed that the juices obtained after the microfiltration and pasteurisation processes had low microbial counts. The microfiltered juice showed a reduction in the soluble solids, acidity and vitamin C content (P = 0.05), while the pasteurised juice showed no change in these parameters (P > 0.05) in relation to the natural sugar cane juice, with the exception of vitamin C, which was not detected after the thermal treatment. In relation to the rheological properties, Newtonian behaviour was observed for both microfiltered and pasteurised juices. The sensory tests on a hedonic scale showed good acceptance of both juices (microfiltered and pasteurised).     

Reactions Involved in Phenolics Degradation from Sugarcane Juice Treated by Ozone

Ozone as an alternative process for the clarification of sugarcane juice has been studied because it presents as an advantage the mineralization of organic compounds that cause color in the crystal sugar. No residues harmful to humans were found after ozonation in contrast to the sulphitation process traditionally used. In this work, the degradation by ozonation of flavonoids and phenolic acids were studied using two compounds: rutin and caffeic acid. Ozonation was efficient and was monitored by liquid chromatography, UV scanning and direct infusion electrospray ionization mass spectrometry. From the collected data, degradation mechanisms and potential mineralization of rutin and caffeic acid after ozonation were proposed.     

Effect of Operating Parameters and Cleaning on the Performance of Ceramic Membranes Treating Partially Clarified Sugar Cane Juice

Abstract

The performance of ceramic membranes with pore sizes of 0.05 and 0.10 µm in purifying limed and partially clarified sugar cane juice was investigated under different operating conditions. From various operating conditions and strategies, switching off the permeate for 5 seconds for every 5 minutes (S5sT5 m) by an automated control valve provided higher flux. From the three pH experiments conducted on the 0.05 µm membrane, the best performance was observed at a pH of 7.5. Amongst the four fouling models tested, the cake filtration model fitted the performance of both membranes with higher accuracy at a transmembrane pressure of 0.5 bar. Filtering the cane juice through the membrane reduced the turbidity by 99.7%, color by 15%, and the starch concentration by 80% as well as increased the purity by 1.4%. The effective cleaning chemical composition from experimental results showed that 1% NaOH and 3000 ppm NaOCl solution performed the best but only for the experiments that were treating limed and partially clarified juice at pH 7.5.     

浓缩蔗糖汁的高效节能热泵并流多效蒸发系统

为了大幅降低蔗糖厂蒸发工艺的能耗,首次将蒸汽喷射式热泵技术、冷凝水闪蒸和引出额外蒸汽预热糖汁等3种节能措施,同时运用于糖汁浓缩并流多效蒸发系统中,并建立了用矩阵方程描述的该系统的数学模型。模型具有很强的通用性,可实现上述节能措施的自由组合和热泵在任意效抽汽的功能,还可推广用于食品工业其它热敏性溶液的蒸发浓缩;模型存在最佳的热泵喷射系数和抽汽位置,同时采用上述3种节能措施且在最佳条件下可以高效节能。用迭代法结合矩阵法求解浓缩糖汁的热泵并流四效蒸发系统的模型,结果表明,同时采用上述3种节能措施,并在满足约束条件的前提下,将糖汁预热至90℃,热泵的喷射系数为0.5,抽汽位置在第2效时节省的生蒸汽消耗量高达41%左右。