Experimental investigation into effects of the natural polymer and nanoclay particles on the EOR performance of chemical flooding in carbonate reservoirs

This paper aims to investigate the tragacanth gum potential as a natural polymer combined with natural clay mineral(montmorillonite,kaolinite,and illite)nanoparticles(NPs)to form NP-polymer suspension for enhanced oil recovery(EOR)in carbonate reservoirs.Thermal gravimetric analysis(TGA)tests were conducted initially in order to evaluate the properties of tragacanth gum.Subsequently,scanning electron microscopy(SEM)and energy-dispersive X-ray(EDX)tests were used to detect the structure of clay particles.In various scenarios,the effects of natural NPs and polymer on the wettability alteration,interfacial tension(IFT)reduction,viscosity improvement,and oil recovery were investigated through contact angle system,ring method,Anton Paar viscometer,and core flooding tests,respectively.The entire experiment was conducted at 25,50,and 75℃,respectively.According to the experimental results,the clay minerals alone did not have a significant effect on viscosity,but the addition of minerals to the polymer solution leads to the viscosity enhancement remarkably,resulting mobility ratio improvement.Among clay NPs,the combination of natural polymer and kaolinite results in increased viscosity at all temperatures.Considerable wettability alteration was also observed in the case of natural polymer and illite NPs.Illite in combination with natural polymer showed an ability in reducing IFT.Finally,the results of displacement experiments revealed that the combination of natural polymer and kaolinite could be the best option for EOR due to its substantial ability to improve the recovery factor.

Alleviation of the plastic deformation of gel ink under strong stress through an esterification of xanthan gum reinforcing its double helix structure

As a natural organic polymer,xanthan gum(XG)can alleviate the plastic deformation of gel ink under strong stress and realize the reasonable regulation of the rheological properties of gel ink.However,as the double-helix structure connected by hydrogen bonds cannot resist the mechanical environment of strong stress,XG shows poor shear resistance.In this study,a polymer gel with interpenetrating polymer network structure was prepared by esterifying XG,taking polystyrene maleic anhydride(SMA)as the modifier.In addition to retaining the excellent rheological properties of XG,the generated polymer gel also exhibited high shear resistance.The optimal addition amount of the esterification reaction modifier was determined as mXG:mSMA=5:3 according to the gel ink standard.With this amount,the viscosity of the modified xanthan gum(SXG)gel increased to 1578.8 mPa·s and 100.7 mPa·s at shear rates of 4 s1 and 383 s1,respectively,and the shear resistance increased more than 2 times compared to the unmodified one.It is because of the ester bond formed by esterification that the reaction strengthens the interaction between molecular segments,enabling the new gel to resist to strong mechanical stress.The new polymer gel studied in this paper and the proposed mechanism of action provide new insights for the development of high-end gel ink and also provide theoretical support for the study of rheological properties of non-Newtonian fluids.

基于GUM法的风电叶片结构试验方法不确定度研究

针对风电叶片全尺寸结构试验方法,首先分析试验过程中所需测量物理量的不确定度因素来源;其次利用GUM法建立不确定度数学模型,然后评定各部分输入量的标准不确定度;最后分析得到叶片结构试验各测试物理量的合成标准不确定度和扩展不确定度,从而建立风电叶片试验不确定度的系统评价方法。

A Novel Fracturing Fluid with High-Temperature Resistance for Ultra-Deep Reservoirs

Ultra-deep reservoirs play an important role at present in fossil energy exploitation.Due to the related high temperature,high pressure,and high formation fracture pressure,however,methods for oil well stimulation do not produce satisfactory results when conventional fracturing fluids with a low pumping rate are used.In response to the above problem,a fracturing fluid with a density of 1.2~1.4 g/cm^(3)was developed by using Potassium formatted,hydroxypropyl guanidine gum and zirconium crosslinking agents.The fracturing fluid was tested and its ability to maintain a viscosity of 100 mPa.s over more than 60 min was verified under a shear rate of 1701/s and at a temperature of 175℃.This fluid has good sand-carrying performances,a low viscosity after breaking the rubber,and the residue content is less than 200 mg/L.Compared with ordinary reconstruction fluid,it can increase the density by 30%~40%and reduce the wellhead pressure of 8000 m level reconstruction wells.Moreover,the new fracturing fluid can significantly mitigate safety risks.

自适应MCM法和GUM法评价直接进样测汞法测定稻谷中总汞的不确定度比较研究

重金属汞污染是危害粮食安全的重要问题,直接进样测汞法的检测过程中需要对检测结果做好质量控制。检测结果需要识别实验过程中各环节对结果的影响大小。基于GB/T 27404—2008《实验室质量控制规范食品理化检测》附录F中对实验室开展新项目所需验证的各种项目:回收率、标准曲线、测定低限、精密度、准确度等。使用自适应蒙特卡洛法(adaptive Monte Carlo method,MCM)和测量不确定度表示指南方法(Guide to the expression of uncertainty in measurement,GUM)分别对直接进样测汞法开展不确定度评定。GUM法得到的不确定范围为(0.0193±0.0017)mg/kg(k=2);MCM法得到的不确定度置信区间(95%)为[0.0177,0.0211];使用MCM Alchimia软件对2种方法的不确定度概率密度拟合曲线,MCM法与GUM法评价结果一致性较好。分析不确定度评定过程中各不确定度贡献率,回收率和标准曲线拟合过程引入不确定度在检出限处引入的不确定度分量较大,建议在方法验证和不确定度评定中使用定量限作为加标回收率和标准曲线最小浓度点。

Effect of defatted flaxseed gum powder addition on the quality of sesame paste

The study explored the influence of defatted flaxseed gum powder(DFGP) on the stability and quality of sesame paste by measuring and analyzing its composition, color, texture, particle size, centrifugal oil separation rate,rheological properties, and microstructure. The results showed that the moisture and polysaccharide content of sesame paste was increased as the DFGP increased. Additionally, the hardness, gumminess, and chewiness of the sesame paste was improved, while the presence of particles with small particle size(1–100 μm) was decreased.The rate of oil precipitation was reduced by 28.99% when the amount of DFGP was 6%. The sesame paste samples exhibited pseudoplastic behavior, demonstrating shear thinning. As the shear rate increased, the apparent viscosity of sesame paste gradually decreased. Both the storage modulus(G’) and the loss modulus(G’’) increased as the shear frequency increased. The microstructure observation revealed that protein and oil were evenly distributed in the sesame paste system, and the addition of DFGP enhanced the bonding between oil and protein.This study can provide valuable references for high-quality sesame paste products in the food industry.

Enhancement of the Antigenotoxic and Antioxidant Actions of Eugenol from Spice Clove and the Stabilizer Gum Arabic on Colorectal Carcinogenesis

Spices are defined as any aromatic condiment of plant origin used to alter the flavor and aroma of foods. Besides flavor and aroma, many spices have antioxidant activity, mainly related to the presence in cloves of phenolic compounds, such as flavonoids, terpenoids and eugenol. In turn, the most common uses of gum arabic are in the form of powder for addition to soft drink syrups, cuisine and baked goods, specifically to stabilize the texture of products, increase the viscosity of liquids and promote the leavening of baked products (e.g., cakes). Both eugenol, extracted from cloves, and gum arabic, extracted from the hardened sap of two species of the Acacia tree, are dietary constituents routinely consumed virtually throughout the world. Both of them are also widely used medicinally to inhibit oxidative stress and genotoxicity. The prevention arm of the study included groups: Ia, IIa, IIIa, Iva, V, VI, VII, VIII. Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the same period and for an additional 9 weeks, the animals received either water, 10% GA, EUG, or 10% GA + EUG by gavage. The treatment arm of the study included groups Ib, IIb, IIIb e IVb, IX, X, XI, XII). Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the subsequent 9 weeks, the animals received either water, 10% GA, EUG or 10% GA + EUG by gavage. The novelty of this study is the investigation of their use alone and together for the prevention and treatment of experimental colorectal carcinogenesis induced by dimethylhydrazine. Our results show that the combined use of 10% gum arabic and eugenol was effective, with antioxidant action in the colon, as well as reducing oxidative stress in all colon segments and preventing and treating genotoxicity in all colon segments. Furthermore, their joint administration reduced the number of aberrant crypts and the number of aberrant crypt foci (ACF) in the distal segment and entire colon, as well as the number of ACF with at least 5 crypts in the entire colon. Thus, our results also demonstrate the synergistic effects of 10% gum arabic together with eugenol (from cloves), with antioxidant, antigenotoxic and anticarcinogenic actions (prevention and treatment) at the doses and durations studied, in the colon of rats submitted to colorectal carcinogenesis induced by dimethylhydrazine.

高效液相色谱-串联质谱法测定玉米蛋白粉中黄曲霉毒素B_(1)测量不确定度评定

采用GUM法和Top-down法对高效液相-串联质谱法测定玉米蛋白粉中的黄曲霉毒素B_(1)测量不确定度进行评定。通过比较2种方法的评定过程和评定结果发现,Top-down法在简化评定步骤、保证评定结果可靠性的前提下,能够充分利用实验室检测数据和质量控制数据,引入检测人员变动、检测仪器更换等带来的不确定度,是一种客观、高效的不确定度评定方法,为饲料中黄曲霉毒素B_(1)检测数据准确溯源提供参考。

GUM评定数字式气压计不确定度的适用性验证

为确保数字式气压计测量不确定度的可靠性,需对现有的测量不确定度表示指南(GUM)评定数字式气压计不确定度的方法进行适用性验证。本文根据国际标准ISO/IEC Guide 98-3:2008附件1给出的蒙特卡洛法(Monte Corlo Method,简称MCM)验证方案,以PTB220型数字式气压计为研究对象,分别采用自适应MCM对GUM方法进行不确定度的评定;将评定结果对比求偏差;根据偏差值是否超限来判定GUM方法适用性。结果表明:所采用的自适应MCM通过迭代增加试验次数,实时判断试验统计意义上的稳定,能有效确保评定结果的可靠性,且仅通过2×10^(4)样本量,计算出对应的评定结果。通过将GUM评定结果与其对比求偏差,分析得出GUM在进行数字式气压计的不确定度评定时偏离程度超过规定范围,说明GUM未能通过验证,即GUM可能不宜适用于该仪器不确定度的评定。

Effect of Gum Arabic from Acacia senegal var. kerensis as an Improver on the Rheological Properties of Wheat Flour Dough

Dough improvers are substances with functional characteristics used in baking industry to enhance dough properties. Currently, the baking industry is faced with increasing demand for natural ingredients owing to increasing consumer awareness, thus contributing to the rising demand for natural hydrocolloids. Gum Arabic from Acacia senegal var. kerensis is a natural gum exhibiting excellent water binding and emulsification capacity. However, very little is reported on how it affects the rheological properties of wheat dough. The aim of this study was therefore, to determine the rheological properties of wheat dough with partial additions of gum Arabic as an improver. Six treatments were analyzed comprising of: flour-gum blends prepared by adding gum Arabic to wheat flour at different levels (1%, 2% and 3%), plain wheat flour (negative control), commercial bread flour and commercial chapati flour (positive controls). The rheological properties were determined using Brabender Farinograph, Brabender Extensograph and Brabender Viscograph. Results showed that addition of gum Arabic significantly (p chapati. These findings support the need to utilize gum Arabic from Acacia senegal var. kerensis as a dough improver.

氯化铵-乙醇交换法-等离子体发射光谱法测定石灰性土壤交换性盐基及盐基总量的不确定度评定

采用电感耦合等离子体发射光谱法对石灰性土壤(pH>7.5)交换性盐基(交换性钾、钠、钙、镁)及盐基总量的测定方法进行系统的不确定度分析,采用GUM法系统性判定整个过程不确定度的主要来源,同时对石灰性土壤盐基总量不确定度来源进行细化确认,对各类不确定度分量进行合成计算,得出合成标准不确定度、扩展不确定度及测定结果的置信区间,并依据各个分量不确定度对合成标准不确定度的贡献得到分析过程需重点控制的关键点。

等离子体发射光谱法测定土壤中有效硫不确定度评定

本文对电感耦合等离子体发射光谱法测定土壤中有效硫的不确定度来源及不确定分量进行了系统性的不确定度分析,并得出合成标准不确定度、扩展不确定度。依据GUM法对分析过程中不确定度的引入进行了详细阐述和计算,最终确定该分析方法的主要不确定度来源为标准曲线拟合引入的不确定度和试样测量重复性引入的不确定度,并总结了对应措施以减小引入的不确定度。

线性回归拟合的测量不确定度评定

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。

基于GUM的麻醉机计量特性的测量不确定度评定

目的:采用GUM法对麻醉机计量特性的测量不确定度进行评定。方法:根据GUM法流程及JJF(鄂)61-2020《麻醉机校准规范》中测量标准,分别对麻醉机的潮气量和输出麻醉气体浓度进行不确定度评定。结果:在容量控制(VCV)模式,设置麻醉机潮气量为400mL,则相对示值误差的扩展不确定度为U_(rel)=3.48%(k=2);设置麻醉机输出麻醉气体浓度为1.5%,则示值误差的扩展不确定度为U_(rel)=0.164%(k=2)。结论:基于GUM法测量不确定度评定,可完成麻醉机计量特性的不确定评定。

基于GUM法和控制图法评定绿茶中三唑磷残留量测定的不确定度

采用气相色谱-串联质谱法(GC-MS/MS)测定绿茶中三唑磷的残留量并进行不确定度评定。依据ISO/IEC Guide 98-3:2008(GUM法)和GB/T 27411-2012《检测实验室中常用不确定度评定方法与表示》(控制图法)对检测结果进行不确定度的分析与量化。结果表明,GUM法和控制图法的评定结果分别为(0.112±0.012)mg/kg,k=2和(0.108±0.018)mg/kg,k=2。GUM法的不确定度主要来源是质量浓度和仪器稳定性,其各自占总不确定度的38.9%和24.7%。控制图法只对检测结果进行统计分析,简单易操作,考察的是检测结果的长期趋势,可在日常检测工作中的内部质量控制应用中得到实施,而GUM法适用于复检样品或客户对不确定度有要求时的评定,计算复杂,但可在短时间内获得不确定度评定结果。

风速传感器实测风速不确定度评定对比研究

在风速传感器实测风速不确定度的评定中,传统方法是将实测风速测量模型简化后采用GUM(guide to the expression uncertainty in measurement)进行评定。但GUM并不适用于复杂模型,为了研究实测风速不确定度评定的可靠方法,对风速传感器分别采用GUM和MCM(Monte Carlo method)进行不确定度评定,对比分析评定结果,并利用MCM评定结果验证GUM的适用性。结果表明,简化模型下GUM和MCM评定结果差异较小,但只有标准不确定度取一位有效数字时,GUM评定方法通过验证,评定结果一致性好;实测模型下MCM和简化模型下GUM评定结果对比得到,两者包络形状相似,但实测风速最佳估计值明显偏大,GUM评定方法不能通过验证;改变部分输入量分布时,两种方法得到实测风速最佳估计值非常接近,但GUM评定得到包含区间比MCM明显增宽,概率分布相差较大,GUM评定方法不能通过验证。因此,应当根据模型的复杂程度、输入量分布情况以及测量结果准确度的要求选择合适的评定方法,如果输入量分布均服从正态分布且对测量准确度要求不高,可使用GUM进行评定,反之建议使用MCM评定以提高观测结果的准确性和可靠性。

基于GUM法的压缩机性能测试不确定度分析

因在压缩机性能测试过程中直接测量得到的各项参数及其不确定度均会对最终结果产生不同程度的影响,为了找到影响结果的主要因素并合理改善这种情况,本文依据GB/T 5773-2016对某涡旋式压缩机进行了性能测试,并基于GUM法对测量结果进行了不确定度分析和敏感度分析。结果表明:压缩机的制冷量测试结果为108.26 kW,合成标准不确定度为0.58 kW,扩展不确定度的相对值为1.07%;对测量结果不确定度产生最大影响的因素是温度仪器的精度,精度提高1倍,可使测量结果的不确定度降低21.15%。

利用TOP-DOWN法评定电感耦合等离子体原子发射光谱法测定土壤样品中铅元素含量的不确定度

采用自上而下的不确定度评定方法(TOP-DOWN法),对酸溶-电感耦合等离子体原子发射光谱法测定土壤样品中铅元素含量的不确定度进行评定,之后使用自下而上的评价方法(GUM法)评定。TOP-DOWN法评定的铅测量不确定度为3.9 mg/kg,GUM法评定的铅测量不确定度为2.8 mg/kg。结果表明,与GUM法评定结果相比,TOPDOWN法评定的土壤中同一水平铅含量的测量不确定度结果基本一致。在积累了大量质量控制样品数据的情况下,与GUM法相比,TOP-DOWN法评定测量不确定度的过程更简单且易于操作,更能反映出实验室检测的长期精密度和准确度水平。

光电式风向传感器测量不确定度的分析与评定

为了提升光电式风向传感器测量结果的可靠性,以EL15-2C型光电式风向传感器为例,通过对其工作原理进行分析,结合现有的检定规程要求,制定出合适的校准方法,通过对其校准过程进行了分析,并根据GUM的要求,对其校准结果进行了测量不确定度的评定,并将评定的扩展不确定度U95应用于示值误差的符合性判定,结果显示其各校准点的U95值均大于1/3的最大允许误差值(MPEV),且测量误差的绝对值均小于MPEV-U95,均满足JJF1094-2002《测量仪器特性评定》规定的符合性评定要求,进而判定所采用的校准方法及测量不确定度评定方案真实可靠,校准结果合格。

玻纤网可燃物含量测量不确定度评定方法的对比分析

使用能力验证结果来验证测量过程的偏倚和精密度受控,采用精密度法对玻纤网可燃物含量测量不确定度进行简化评定。同时结合本实验室的该参数试验方法、仪器等因素,考虑了主要不确定度来源,建立测量模型采用GUM法进行评定和分析。总结出2种方法在该参数的不确定度评定的优劣,为不确定度评定在检测实验室中的应用提供参考。