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Evaluation of flocculation characteristics of kaolinite dispersion system using guar gum:A green flocculant

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International Journal of Mining Science and Technology 2019年第5期29卷 745-755页

作者： R.K.Dwari B.K.Mishra Mineral Processing Department CSIR-Institute of Minerals and Materials TechnologyBhubaneswar 751013India Indian Institute of Technology Goa 403401India

This paper reports the systematic investigation on the flocculation,sedimentation and consolidation characteristics of kaolinite using guar gum as a green flocculant.In-situ flocculation behavior of kaolinite at various pH,guar gum dosages,and ionic strength were studied using a light scattering technique.The effect of these parameters on the settling rate,solid consolidation,and supernatant liquid clarity was recorded.The morphology of kaolinite and flocculated kaolinite aggregates were analyzed using FESEM.The morphology studies suggest that it is poorly crystalline with multiple steps on edge,broken edge;laminar with high aspect ratio and have rough basal surface.The complex irregularity on the basal surface and the presence of multiple steps in the edges,broken edges(hydroxyl groups)have facilitated the guar gum adsorption.The isoelectric point of kaolinite is pH 3.96.The pH,ionic strength and flocculant dosage have a significant effect on the kaolinite settling rate.The guar gum has exhibited excellent turbidity removal efficiency at pH 5.The turbidity removal is inefficient at pH 10.However,guar gum has shown high turbidity removal with 80%transmission at pH 10 in the presence of a KNO3 electrolyte.

关键词： Guar gum Dewatering Kaolinite Light scattering Morphology Flocculation

The selective effect of food-grade guar gum on chalcopyrite-monoclinic pyrrhotite separation using mixed aerofloat(CSU11) as collector

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International Journal of Minerals,Metallurgy and Materials 2018年第10期25卷 1123-1131页

作者： Xiong Chen Guo-hua Gu Li-juan Li Ren-feng Zhu School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China Zhaojin Mining Industry Company Limited Yantai 264000China

The flotation separation of chalcopyrite from monoclinic pyrrhotite using food-grade guar gum(FGG) as a depressant was studied through flotation tests, kinetic studies, dynamic potential measurements, adsorption experiments, and infrared spectral analyses. The microflotation results showed that the flotation separation of chalcopyrite from monoclinic pyrrhotite could not be realized by adding mixed aerofloat(CSU11) alone. The depressant FGG exhibited a selective depression effect on monoclinic pyrrhotite by controlling the pulp pH range from 5.0 to 6.0, with a maximum floatability variation of 79.36% in the presence of CSU11. The flotation kinetics, zeta-potential, adsorption, and infrared spectroscopy studies revealed that the FGG could absorb more strongly on the surface of monoclinic pyrrhotite than on the surface of chalcopyrite. In addition, the results revealed that the interaction of FGG with the monoclinic pyrrhotite surface was governed primarily by strong chemisorption, whereas FGG mainly bonded to chalcopyrite through hydrogen bonding. This difference was responsible for the excellent depression selectivity of FGG toward monoclinic pyrrhotite flotation and weak depression effect toward chalcopyrite flotation.

关键词： chalcopyrite monoclinic pyrrhotite flotation separation food-grade guar gum

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加速退化试验测量不确定度评定方法

航空学报 2023年第7期44卷 129-139页

作者：郭宏轩孙富强北京航空航天大学可靠性与系统工程学院北京100191 可靠性与环境工程技术国防科技重点实验室北京100191

受测量分散性、仪器误差等因素影响,加速退化试验中存在测量不确定性问题。提出了加速退化试验测量不确定度的传播与评定方法,以提高试验评估结果的准确性和可信性。首先,介绍了加速退化试验中的测量不确定度来源,并结合维纳过程加速退... 详细信息

受测量分散性、仪器误差等因素影响,加速退化试验中存在测量不确定性问题。提出了加速退化试验测量不确定度的传播与评定方法,以提高试验评估结果的准确性和可信性。首先,介绍了加速退化试验中的测量不确定度来源,并结合维纳过程加速退化模型参数估计过程分析了测量不确定度的传播效应;其次,分别利用测量不确定度指南评定法(gum)和蒙特卡洛法,量化评定了加速退化试验中性能观测数据测量不确定度对正常应力水平下产品可靠性评估结果的影响;最后,采用某型空间用高分子传感器案例对本文所提方法进行验证,并针对2种方法的估计结果进行了对比分析,验证了所提出方法的有效性。

关键词：加速退化试验测量不确定度 gum 蒙特卡洛法高分子传感器

Evaluation of gum mastic(Pistacia lentiscus) as a microencapsulating and matrix forming material for sustained drug release

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Asian Journal of Pharmaceutical Sciences 2017年第5期12卷 424-432页

作者： Dinesh M.Morkhade Department of Pharmaceutical Sciences Rashtrasant Tukadoji Maharaj Nagpur University Campus

In this study, a natural gum mastic was evaluated as a microencapsulating and matrixforming material for sustained drug release. Mastic was characterized for its physicochemical properties. Microparticles were prepared by oil-in-oil solvent evaporation method. Matrix tablets were prepared by wet and melt granulation techniques. Diclofenac sodium(DFS) and diltiazem hydrochloride(DLTZ) were used as model drugs. Mastic produced discrete and spherical microspheres with DLTZ and microcapsules with DFS. Particle size and drug loading of microparticles was in the range of 22–62 μm and 50–87%, respectively. Increase in mastic:drug ratio increased microparticle size, improved drug loading and decreased the drug release rate. Microparticles with gum: drug ratio of 2:1 could sustain DLTZ release up to 12 h and released 57% DFS in 12 h. Mastic produced tablets with acceptable pharmacotechnical properties. A 30% w/w of mastic in tablet could sustain DLTZ release for 5 h from wet granulation,and DFS release for 8 h and 11 h from wet and melt granulation, respectively. Results revealed that a natural gum mastic can be used successfully to formulate matrix tablets and microparticles for sustained drug release.

关键词： gum mastic Diclofenac sodium Diltiazem hydrochloride Microparticles Matrix tablets Sustained release

Use of seed gums from Tamarindus indica and Cassia fistula as controlled-release agents

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Asian Journal of Pharmaceutical Sciences 2018年第5期13卷 398-408页

作者： Kampanartb Huanbutta Wancheng Sittikijyothin Faculty of Pharmaceutical Sciences Burapha University Faculty of Engineering Department of Chemical Engineering Burapha University

Most seed gums have been widely used in oral and topical pharmaceutical formulations, cosmetics, and food products because of their hydrophilic properties. gums from Tamariudus indica and Cassia fistula seeds were chemically modified by carboxymethylation to improve their functionalities. The objective of the present study was to characterize and evaluate crude and carboxymethylated gums from T. indica and C. fistula seeds to achieve the controlled-release of diclofenac sodium(DS) in matrix tablet form. Both crude and carboxymethylated gums were characterized by Fourier transform infrared spectroscopy, Xray diffraction, and scanning electron microscopy. The results revealed that the gums were successfully modified by carboxymethylation and that the modified gums were amorphous in structure and had better flow properties. The carboxymethylated gums from both plant seeds did not exhibit cytotoxicity at concentrations lower than 0.5 mg/ml. All gum samples used as polymeric controlled-release agents were formulated into DS matrix tablets. Hardness and thickness tests were conducted as in-process tests. Drug content estimation and in vitro drug release studies were carried out to evaluate the matrix tablets. Increasing the concentration of gums increased compression time and hardness while it reduced the thickness. Furthermore, the results fitted well with the Korsmeyer–Peppas model. Moreover, the DS tablets were found to release the drug by super case II transport(relaxation). In summary, the carboxymethylated gum from T. indica and C. fistula seeds is an excellent, naturally sourced gum with high physicochemical and functional qualities, and can potentially be used in pharmaceutical applications as a disintegrant, diluent, and drug release-controlling agent.

关键词： Seed gum Tamarindus indica Cassia fistula Carboxymethylated gum Controlled-release agent Swelling

Exploiting a readily available but hard to digest resource:A review of exudativorous mammals identified thus far and how they cope in captivity

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Integrative Zoology 2018年第1期13卷 94-111页

作者： Francis CABANA Ellen S.DIERENFELD Wirdateti Giuseppe DONATI K.A.I.NEKARIS Wildlife Nutrition Centre Wildlife Reserves Singapore Nocturnal Primate Research Group Oxford Brookes UniversityOxfordUK Ellen S.Dierenfeld LLCSt.LouisMissouri USA Zoological Division Indonesian Institute of ScienceCibinongIndonesia

gum is a widely available carbohydrate,composed mainly of non-digestible structural carbohydrates.No mammalian enzymes can digest gum;therefore,a mammal ingesting gum must rely on microbial fermentation to access the energy it possesses.gums are relatively nutrient poor.Despite this,some mammals have evolved to exploit this food resource.We aim to review the literature for all mammal species which have been recorded to ingest gum,whether quantified or not,and discuss this in the context of their evolutionary adaptations.We also investigated the recommended captive diets for these species to look at whether gum is recommended.We conducted a literature search on ISI Web of Knowledge to tabulate all mammal species observed ingesting gum and classified them as obligate,facultative or opportunistic feeders.We encountered 94 mammal species that eat gum in the wild(27 obligate feeders,34 facultative feeders and 33 opportunistic feeders).Obligate feeders have entirely evolved to exploit this resource but were found to not be given gum in captivity,which may explain why they are failing to thrive,as opposed to facultative feeders,which have fewer issues.gum may be necessary for the health of obligate feeders in captivity.Future research should focus on the physiological effects that gum ingestion poses on different digestive systems.

关键词： feeding ecology gum husbandry marsupial primate

Selective depression behavior of guar gum on talc-type scheelite flotation

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International Journal of Minerals,Metallurgy and Materials 2017年第8期24卷 857-862页

作者： Yong-zhong Zhang Guo-hua Gu Xiang-bin Wu Kai-le Zhao School of Geosciences and Info-Physics Central South University Department of Land and Resources of Hunan Province School of Minerals Processing and Bioengineering Central South University

The depression behavior and mechanism of guar gum on talc-type scheelite flotation were systematically investigated by flotation experiments, adsorption tests, zeta-potential measurements, and infrared spectroscopic analyses. The flotation results for monominerals, mixed minerals, and actual mineral samples indicated that guar gum exhibited much higher selective depression for talc than for scheelite. Bench-scale closed-circuit tests showed that a tungsten concentrate with a WO_3 grade of 51.43% and a WO_3 recovery of 76.18% was obtained. Adsorption tests, zeta-potential measurements, and infrared spectral analyses confirmed that guar gum absorbed more strongly onto the talc surface than onto the scheelite surface because of chemisorption between guar gum and talc. This chemisorption is responsible for the guar gum's highly selective depression for talc and small depression for scheelite. The flotation results provide technical support for talc-type scheelite flotation.

关键词： scheelite talc guar gum flotation depression mechanism

Preparation of pure gum raw materials-low brown algae application

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Journal of Oceanology and Limnology 2019年第3期37卷 892-897页

作者： WAN Mengfei LIU Zhongdong CHEN Yongfu LU Caiyuan LI Kechang WANG Fahe WANG Xiaomei LIU Boxiang Food Science and Technology Henan University of TechnologyZhengzhou 450001China Ruilin Chem.Ltd. Hangzhou 310000China State Key Laboratory of Bioactive Seaweed Substances Qingdao Brightmoon Seaweed Group Co.Ltd.Qingdao 266000China Montgomery Lab Stanford UniversityCAUSA

Octenylsuccinate starch ester,also called pure gum,is non-toxic and odourless modified starch which is widely used in many food fields.This study synthesized pure gum in a reaction kettle using the low molecular weight trehalose and octenyl succinic acid.An orthogonal test was carried out to find how the reaction factors aff ect the synthetization of octenylsuccinic acid polysaccharide ester and to optimize the reaction at single factor level.The optimal products were obtained using 1:2 of octenylsuccinic acid:alginic acid,catalysed by 0.1% p-toluenesulfonic acid catalyst for 1.5h at 200℃ under vacuum conditions.The gained product contains up to 46%of seaweed gel monoesters.The degree of esterification of the polysaccharide is controlled by the use of the small-molecule trehalose.Compared with the traditional methods,our process can reduce raw material cost and improve emulsification stability of pure gum.These all can significantly improve the market competitiveness of pure gum products.

关键词： trehalose pure gum synthesis

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线性回归拟合的测量不确定度评定

计量学报 2023年第4期44卷 664-670页

作者：夏玉国彭友志刘正华宋潇曾卓武汉地震计量检定与测量工程研究院湖北武汉430071 中国地震局地震研究所地震大地测量重点实验室湖北武汉430071 湖北省地震局湖北武汉430071

利用gum对最小二乘线性回归拟合结果进行测量不确定度评定,提出了同时顾及因变量以及系数矩阵中自变量误差影响的标准不确定度通用式。首先,阐述了线性回归拟合模型以及最小二乘估计结果;其次,考虑系数矩阵影响,推导了拟合参数与拟合值... 详细信息

利用gum对最小二乘线性回归拟合结果进行测量不确定度评定,提出了同时顾及因变量以及系数矩阵中自变量误差影响的标准不确定度通用式。首先,阐述了线性回归拟合模型以及最小二乘估计结果;其次,考虑系数矩阵影响,推导了拟合参数与拟合值关于自变量、因变量的灵敏系数以及标准不确定度通用公式,同时考虑相关性,给出了对变量相关进行特殊处理后的标准不确定度通用公式;最后,以线位移传感器灵敏度(不需考虑相关性)和光电测距仪加乘常数(考虑相关性)为例,与蒙特卡洛方法(MCM)进行比较分析。结果表明,不需考虑相关性以及考虑相关性下,基于gum评定方法的标准不确定度通用公式计算结果与MCM评定方法结果基本一致。

关键词：计量学测量不确定度评定线性回归拟合系数矩阵相关性 gum MCM