对GB/T 13096.2-91中弓形试样截面惯性矩计算公式的讨论

本文认为GB／T13096．2－91中计算弓形试样截面惯性矩的公式有误，同时指出在某些手册中有关计算公式也有误，为此作者给出正确的计算公式，并与美国ASTMD4476－85中的近似公式进行了比较，结果表明大多数情况下，两个公式的计算结果差异在1％以内，由此证明了本文推荐计算公式的合理性。     

新发布的美国ASTM D3324—89a标准参比炭黑

1999年新出版的 ASTM99卷中对 ASTM D3324-88《用标准参比炭黑改善试验方法的再现性》进行了重新修订。修订后的标准编号是 ASTM D3324-89a。在新修订的标准中发布了一套6个标号的标准参比炭黑,总代号为 SRB-4(Standard ReferenceBlack)。6个标号的炭黑及对应的品种分别为 A—4 N 326,B—4 N 330,C—4 N 121,D—4 N762,E—4 N 660和F—4 N 683。标准中给出了这六种炭黑的标准测试方法。其精密度(重复性,最小有效差值),炭黑性能(目标值,典型值)及性能范围见表1。新发布的 SRB—4与原标准(ASTMD3324-88)中的 SRB—3(见表2)相比有以下差异。     

倾点测试法ASTM D5950和GB/T 3535、ASTM D97的差异性分析

介绍了目前国内外石油产品的倾点测试方法,主要介绍了ASTM D5950-14《石油产品倾点标准试验法(自动倾斜法)》,并与手动测定法ASTM D97-2012《石油产品倾点测定法》和GB/T 3535—2006《石油产品倾点测定法》做了对比测试。结果表明:ASTM D5950-14等效于GB/T 3535—2006和ASTM D97-2012进行石油产品倾点的测试。     

减压蜡油加氢裂化工艺柴油产品十六烷值的分析与预测

考察了现有十六烷指数计算公式对多产中间馏分油型加氢裂化催化剂柴油的适用性,提出了计算多产中间馏分油型加氢裂化催化剂柴油十六烷值与轻油转化率、链烷烃含量、环烷烃含量、芳烃含量和密度的关联式。结果表明:采用常用计算十六烷值公式、石油化工行业标准SH/T0694、国家标准GB11139和ASTM D976-80方法计算得到的十六烷值的偏差分别为0.97、0.91、0.84和0.96,当实测的十六烷值越小时,采用上述方法计算十六烷值的偏差越大,均不能有效预测多产中间馏分油型加氢裂化催化剂柴油的十六烷值;所建关联式能够很好地预测多产中间馏分油型加氢裂化催化剂柴油的十六烷值,计算十六烷值与实测十六烷值偏差不超过5%。     

对ASTM D1298标准新版本变动的研究

本文通过对ASTM D1298标准新旧版本的对比学习,指出了新版本ASTM D1298-12B相比旧版本的若干变动之处。其中,最重要的变动在依据ASTM D1298-12B计算密度时,首次使用了ADJUNCT TO ASTM D1250-04中附带的计算程序,而不再是以往推荐的纸质印刷表格。本文用这两种不同的计算途径针对同一组实验数据进行了对比,从学术意义和对实际工作的影响两方面对这一系列变动给予评价,为相关检验机构和从业人员提供了参考和借鉴。     

检查手套用新型聚烯烃复合润滑涂层的研制

研究以改性聚烯烃和改性水基聚氨酯为主体材料的新型复合润滑涂层的制备及影响因素。改性聚烯烃和改性水基聚氨酯的质量分数均为0．04，浸渍时间为15s，干燥温度为112℃，手套的光滑性能最佳，滑爽级别达到5级。以此条件制备的手套物理性能达到ASTM D 3578-2001标准，残余粉质量分数符合ASTM D 6124-2001标准要求。     

MTO级甲醇产品高锰酸钾时间分析方法的探讨

根据ASTM E 34-2003[1]、ASTM D1363-2006[2]、GB/T6324.3-2011[3]等工业甲醇的高锰酸钾试验标准,文章对甲醇产品锰酸钾时间分析方法进行了探讨。此分析的目的是确定一个观测数值或大概计算数值与相关国家技术规范的符合性,分析结果应修约到与技术规范限值的小数点保留位数相一致。此分析方法适用于在甲醇及MTO级中存在有能还原高锰酸甲杂质的测定。     

机织物撕破强力和起毛起球测试方法比较

通过采用ASTM D 2261、ASTM D 1424、GB/T 3917.2、GB/T 3917.3四种撕破强力测试方法和ASTM D3512、ISO 12945-1、ISO 12945-2和GB/T 4802.1四种抗起毛起球测试方法,分别测试同一机织物的撕破强力和起毛起球性,并对测试结果进行比较。结果表明,上述方法对同一机织物测得的撕破强力不同,由大到小的顺序为GB/T 3917.3ASTM D 2261=GB/T 3917.2ASTM D 1424;而用ISO 12945-2方法所测机织物的抗起毛起球性结果低于ASTM D 3512、ISO 12945-1和GB/T 4802.1,上述结论提醒各生产厂家和供应商在提供产品时,要关注相关标准和国家法规要求,以避免不必要的损失。     

杀菌防霉涂料

201203061含金属物质的抗菌聚硅氧烷材料及其在涂料中的应用：US2011—236343[美国专利申请公开]／美国：NDSU Research Foundatlon（Chlsholm，Bret Ja等）．-2011．D9．29．-22页．-2010／661902（2010．03．25）：IPCA01N55／10（424—78．17）     

纤维过滤介质过滤压力损失理论计算

为便于计算纤维过滤介质过滤压力损失,对目前各种纤维过滤介质过滤压力损失理论计算公式及半经验公式进行分析计算,将理论计算结果与实验测试结果进行对比分析发现各种理论计算结果普遍相偏大,需要对纤维的非均匀分布进行修正,修正后的大部分计算结果与实验结果基本吻合,同时对理论计算公式的鲁棒性进行了分析。计算结果准确性和鲁棒性兼顾的理论计算公式,较适宜于实际过滤材料压力损失的预测。     

国标与ASTM浮辊剥离方法

对比了GB／T7122—1996高强度胶黏剂剥离强度的浮辊法测定与ASTMD3167—03a胶黏剂浮辊剥离强度的标准试验方法,从几个方面分析了两种试验方法的差别以及对试验结果的影响,并由此得出同种胶黏剂分别采用以上方法试验得出的数据会有一定差异的结论,在对胶黏剂进行浮辊剥离强度复验时应当采用该胶黏剂出厂检验所采用的检测方法。     

Accurate measurement method for the residues in liquefied petroleum gas (LPG)

A newly developed LPG residues measurement method is reported. First, residues in LPG is extracted into n-hexane. Then, the residues in n-hexane is analyzed by gas chromatography (GC). The method gives accurate results and good repeatability. It is powerful even at low concentration range where ASTM D2158-02 is not applicable. The method is easier to operate and takes less time compared with ASTM D2158-02 method.     

Determination of Acid Number of Biodiesel and Biodiesel Blends

Due to an increase in the commercial use of biodiesel and biodiesel blends, both ASTM D 6751 and EN 14214 include the acid number (AN) as an important quality parameter. It was found that determination of AN of biodiesel and biodiesel blends using the ASTM D 974 results in large values of repeatability (up to 73.41%) and larger percentage error (up to 42.88%). Therefore, ASTM D 974 has been modified using a lower concentration of base (0.02 M KOH instead of 0.1 M KOH) as well as reducing the amount of toxic titration solvent from 100 mL to only 10 mL. This makes the modified ASTM D 974 as a green analytical method which uses a reduced amount of toxic solvent. This modified method significantly reduced the maximum percentage error from 42.88 to 5.92%. The application of this modified ASTM D 974 for the determination of AN of biodiesel and biodiesel blends was studied. The accuracy of this modified ASTM D 974 for biodiesel (B100) was measured to be within 3.51% over the AN range of 0.313–0.525 mg KOH/g and maximum repeatability was decreased from 8.37 to 2.75% within this AN range which is far below the ASTM D 974 stated repeatability specifications. For B20, B10, B5, B2, and B1, the most accurate values were measured at AN values of 0.177, 0.067, 0.072, 0.126, and 0.096 mg KOH/g, respectively. Excellent linearity values of R ² for calculated and experimentally determined AN were obtained. The difference between the experimental and the calculated AN for all biodiesel and biodiesel blend samples was within ± 0.018 mg KOH/g. This extensive study has demonstrated that this modified ASTM D 974 is a reliable method for the determination of AN and could be used for establishing the specifications of AN for biodiesel and biodiesel blends ranging from B1 to B20 in quality standards.     

Determination of hydrogen content, gross heat of combustion, and net heat of combustion of diesel fuel using FTIR spectroscopy and multivariate calibration

The precise determination of the heat of combustion is of great importance for trading automotive diesel. The net heat of combustion (NHC) of fuel is related to the hydrogen elemental composition of fuel as obtained by elemental analysis. Heat of combustion expressed as gross heat of combustion (GHC) and net heat of combustion (NHC) have been predicted from data obtained by proximate analysis (density, ash, water and sulphur content) (ASTM D4868). GHC was obtained using bomb calorimetry (ASTM D240). The results of ASTM D4868 and ASTM D240 were found in good agreement. GHC and NHC fall within the relatively narrow range 45.24-46.08 and 41.91-43.27 MJ/kg, respectively. GHCs of tested diesel samples are, on average, about 7% greater than NHCs. The present paper also present a simple analytical method for determination of hydrogen content, GHC, and NHC of automotive diesel fuel using FTIR spectroscopy and partial-least squares calibration (PLS-1). PLS-1 had a high prediction power for prediction of hydrogen from FTIR spectra of diesel samples. The spectral ranges used in calibration were 400-670 and 2846-2970 cm⁻¹. On the other hand, classical least squares calibration (CLS) was found invalid for determination of hydrogen content in diesel. The results obtained by the proposed analytical method were almost to those obtained by ASTM D4868 and ASTM D240. PLS-1 method, offers a simple and reliable analytical method for quantification of hydrogen content in diesel samples without running expensive analysis like those carried out using carbon, hydrogen, and nitrogen (CHN) instruments.     

Basic properties of palm oil biodiesel–diesel blends

The basic properties of several palm oil biodiesel–diesel fuel blends were measured according to the corresponding ASTM standards. In order to predict these properties, mixing rules are evaluated as a function of the volume fraction of biodiesel in the blend. Kay’s mixing rule is used for predicting density, heating value, three different points of the distillation curve (T10, T50 and T90), cloud point and calculated cetane index, while an Arrhenius mixing rule is used for viscosity. The absolute average deviations (AAD) obtained were low, demonstrating the suitability of the used mixing rules. It was found that the calculated cetane index of palm oil biodiesel obtained using ASTM D4737 is in better agreement with the reported cetane number than the one corresponding to the ASTM D976. This result is most likely due to the fact that the former standard takes into account the particular characteristics of the distillation curve.     

橡胶挤出机平均温差分析与计算

从理论上推导挤出机平均温差的计算公式，并指出与一般换热器平均温差计算的异同。     

Parametric study for tensile properties of molded high-density polyethylene for applications in additive manufacturing and sustainable designs

Test specimens following ASTM D638 standards are frequently used to measure the tensile properties of reinforced and unreinforced polymers machined with traditional machining and emerging manufacturing methods (additive manufacturing/3D printing). However, designs of large engineering structures may rely on mechanical properties based on ASTM D3039 for fiber-reinforced polymer composites. This parametric study examines the scaling effects present in uniaxial tensile test specimens of molded high-density polyethylene (HDPE), with geometries ranging from Types I to IV of ASTM D638 to ASTM D3039. HDPE is a thermoplastic polymer that is recyclable, can be 3D-printed, and has a wide range of engineering applications, from bottles to pipes to radiation protection shielding. The mechanical properties test results for the molded HDPE samples are validated using a Monte Carlo simulation to estimate uncertainties for the probability distribution of maximum stress at the yield point. A Finite Element study based on the empirical model shows how the proposed approach can be adopted for design purposes. The results of this work are a useful tool to enhance confidence in the tensile mechanical properties of ASTM D638 Types II and IV geometries as statistically similar to those of ASTM D3039 samples, impacting engineering designs with traditional and emerging manufacturing methods.     

Total Acid Number Determination of Biodiesel and Biodiesel Blends

The repeatability and accuracy of the total acid number (TAN) measurement for soy oil-based biodiesel–diesel blends using the ASTM D664 method was studied. ASTM D664 is the standard reference method for measuring the acid number of both biodiesel and petroleum-derived diesel, which specifies procedures for the determination of acidic components in biodiesel and diesel, and claims good repeatability and mediocre reproducibility during application, but cites no information on accuracy. However, the accuracy of this method is very important for setting the specifications for biodiesel blends, especially for B20 (a mixture composed of 20% biodiesel with 80% diesel) because of its wide commercial production. The accuracy of ASTM D664 was measured to be within 4.13% for B20 in the acid number range of 0.123–0.332 mg KOH/g. The maximum repeatability was approximately 5.21% at an acid number of 0.123 mg KOH/g. Within the ASTM D6751-07b specification for TAN (0.5 mg KOH/g), good accuracy and repeatability were also obtained. Accuracy specification and electrode operation suggestions for ASTM D664 are also given.     

Densities of vegetable oils and fatty acids

Complete data for density as a function of temperature have been measured for a number of vegetable oils (crambe, rapeseed, corn, soybean, milkweed, coconut, lesquerella), as well as eight fatty acids in the range C₉ to C₂₂ at temperatures from above their melting points to 110°C (230°F). The specific gravity and density measurements were performed according to American Society for Testing and Materials (ASTM) standard test methods D 368, D 891 and D 1298 for hydrometers and a modified ASTM D 369 and D 891 for pycnometers. Correlation constants, based on the experimental data, are presented for calculating the density of fatty acids and vegetable oils in the range of temperature from 24°C (75°F) or the melting point of the substance, to 110°C (230°F). The constants are valuable for designing or evaluating such chemical process equipment as heat exchangers, reactors, process piping and storage tanks. Estimated density of fatty acids by a modified Rackett equation is also presented.