Delignification kinetics of empty fruit bunch (EFB): a sustainable and green pretreatment approach using malic acid-based solvents

Recently, the development of efficient and environmentally benign solvents has received great attention to replace current harsh organic solvents. In this context, low-transition-temperature mixtures (LTTMs) have emerged as favorable green solvents for biomass delignification. Palm oil biomass, empty fruit bunch (EFB) was pretreated with commercial l-malic acid and microwave hydrothermally extracted cactus malic acid-derived LTTMs at 60, 80, and 100 °C. The LTTMs applied in this study were derived from malic acid–choline chloride–water and malic acid–monosodium glutamate–water with a molar ratio of 2:4:2 and 3:1:5, respectively. Three first-order reactions were used to express the delignification kinetic model of EFB. The first term was based on the initial stage and assigned as infinite due to the fast rate of delignification which could not be detected. The second and third terms were proportional to bulk and residual delignification stages. A good agreement was obtained between the kinetic model and the experimental data obtained in this study with R²?≥?0.91. The activation energies for the delignification reactions using l-malic acid and cactus malic acid-based LTTMs in the bulk and residual stages were approximated as 36–56 and 19–26 kJ/mol and 34–90 and 47–87 kJ/mol, respectively.     

Hydrogen from renewable palm kernel shell via enhanced gasification with low carbon dioxide emission

Hydrogen economy has become more attractive with the energy crises and environmental issues associated with fossil fuel utilization more so with the discovery that hydrogen can be produced from renewable biomass. This provides good prospects to Malaysia that generates abundant palm wastes. Nevertheless, there is still limited knowledge on kinetics parameters for hydrogen production from palm kernel shell (PKS) gasification. Hence, this work aims to develop a mathematical model that is able to describe the kinetics of steam gasification of PKS with in situ CO₂ capture while considering tar formation. A mean-squared error minimization approach has been used to estimate the kinetics parameters of the gasification process. Using the calculated kinetics parameters the process efficiencies are profiled with respect to the effect of gasification temperature, steam/biomass ratio and sorbent/biomass ratio. The parametric study indicates that the three variables promote hydrogen production at different degree of influence. This developed model can be further extended to incorporate optimization study on the potential clean production of hydrogen from PKS.     

沙尔布尔山中上志留统火山沉积岩及其沉积环境

通过我们对沙尔布尔山1：50000地质填图和综合研究工作将志留系的火山岛弧系划分为喷发溢流相、震积相、火山碎屑流相、火山碎屑浊流相、正常沉积岩相等事件沉积．对各相特征及其事件沉积学进行了探讨，分析了它们的时空结构及沉积环境的关表     

基于多策略的乌孜别克语名词词干识别研究

乌孜别克语名词词干识别是自然语言处理领域的基础研究,主要方法是从句子中提取名词词干,提高名词标注效率和准确性。该文首先陈述形态分析、形态特征对识别其词性的作用,然后讨论乌孜别克语的词类划分标准、名词的形态特征,乌孜别克语西尔里文转换拉丁文,乌孜别克语词汇翻译、标注技术,总结词缀歧义及消解规则。该文提出利用形态规则、词典、最大熵融合策略,设计现代乌孜别克语新词中名词词干识别算法,其中包括特征选择及参数估计、词内部特征、前后依存词特征等。最后以乌孜别克语网站文本作为验证对象,对名词词干进行统计与分析。     

S形焊接金属波纹管振动特性分析

针对S形焊接金属波纹管密封的振动问题,选用面体代替波片实体单元进行数值建模和模态分析;研究了单元尺寸对波纹管振动频率的影响,提出了波片选用面体单元时的单元尺寸应小于0.5 mm,并验证了其有效性。利用电动振动试验平台进行振动试验测试,得到了波纹管的振动特性曲线。通过对比分析仿真结果和试验测试结果,确定了波纹管的前6阶振动固有频率和振型,揭示了波纹管的振动机制和影响因素,阐明了波纹管的数值建模方法和试验测试技术。研究结果对焊接金属波纹管密封的设计、制造和应用提供了参考。     

基于形态分析的现代维吾尔语名词词干识别研究

现代维吾尔语名词词干识别是自然语言处理领域的重要基础性研究,主要目的是从句子中提取名词词干,提高名词识别效率。首先陈述形态分析概念,通过这些形态特征可以准确地识别其词性的意义;其次讨论维吾尔语的词类划分标准、名词的形态特征分析,总结词缀歧义及消解规则;该文提出研究总体思路,设计现代维吾尔语新词中名词识别算法,其中包括特征选择及参数估计、词内部特征、前后依存词特征等;最后将初中、高中物理维吾尔语教材作为验证对象,对名词词干进行统计与分析。     

QTT 主动面系统控制网络初步设计

110 m 口径全可动射电望远镜(Qitai radio Telescope, QTT) 使用主动面调整技术修正天线因重力、温度等造成的天线表面形变,提高天线高频工作下的接收效率。主动面系统作为一种多节点控制网络,需要对其通信技术及网络拓扑进行合理设计,满足功能和性能的需要。通过分析国内外采用主动面技术的大口径射电望远镜的控制网络形式,并对比了典型工业以太网与现场总线的优劣,采用工业以太网作为控制网络的通信协议。分别基于Ethernet Powerlink 和EtherCAT 两种工业以太网技术设计了QTT 主动面分布式控制网络。     

Acid esterification of a high free fatty acid crude palm oil and crude rubber seed oil blend: Optimization and parametric analysis

Free fatty acids content plays an important role in selecting the appropriate route for biodiesel production. Oils with high content of free fatty acids can be treated by acid esterification where an alcohol reacts with the given oil in the presence of acid catalyst. In the current study, an equivolume blend of crude rubber seed oil and crude palm oil is fed to the reaction with methanol as the alcohol of choice and sulfuric acid. Selected reaction parameters were optimized, using Taguchi method for design of experiments, to yield the lowest free fatty acid content in the final product. The investigated parameters include alcohol to oil ratio, temperature and amount of catalyst. The effect and significance of each parameter were then studied based on the fractional factorial design and verified by additional experiments. The optimum conditions for acid esterification which could reduce the free fatty acid content in the feedstock to lower than 0.6% (95% reduction) were 65 °C, 15:1 methanol to oil ratio (by mole) and 0.5 wt% H₂SO₄ after 3 h of reaction time. Temperature had been found to have the most effect on the reduction of free fatty acids followed by reactants ratio while increasing catalyst amount had nominal effect.     

Torrefaction of oil palm wastes

This paper describes the effect of torrefaction on the basic characteristics of agricultural biomass wastes in Malaysia, such as empty fruit bunches (EFB), mesocarp fiber and kernel shell as a potential source of solid fuel. Mesocarp fiber and kernel shell exhibited excellent energy yield values higher than 95%. EFB, on the other hand, exhibited a rather poor yield of 56%.     

Evaluation of the energy saving opportunities for palm oil refining process: Sahabat Oil Products (SOP) in Lahad Datu,Malaysia

Palm Oil industry is one of the major contributors to Malaysia’s economic activity. Accounting for 39 % of the world palm oil production and 44 % of world exports, Malaysia holds an important niche in fulfiling the growing global needs for oils and fats sustainably. This industry has high potential for further improvements especially in terms of energy saving as a major contributor to cost and emission reduction. An analysis of the refining process of palm oil in Sahabat Oil Products, Lahad Datu has been performed and presented in this paper for scoping potential energy and cost savings using heat integration. A first stage optimisation of the minimum temperature difference, ?T _min, of a heat exchanger network (HEN) has been performed. The goal has been to evaluate the maximal possible heat recovery as well as the appropriate placement of utilities. The HEN design is presented in both grid diagram and shifted retrofit thermodynamic grid diagram (SRTGD). SRTGD representation has been illustrated in this paper as a useful tool for guiding eventual future retrofit. The capital-energy trade-off of the heat recovery targets indicates optimum ?T _min of 12.3 °C. The hot and cold utility targets at ?T _min = 12.3 °C are 1419 and 1649 kW, indicating potential saving of 3.5 and 3.1 % as compared to the existing utility consumption and emissions. Future work could proceed further to seek potentially viable retrofit of the existing heat recovery network.