试样用硝酸、氢氟酸、硫酸溶解,以强碱分离法沉淀大部分干扰离子,以2.0mL 150g/L抗坏血酸溶液、1.0mL 10g/L草酸溶液掩蔽Al 3+、Mn2+、Ti 4+、V(Ⅴ)、Cl-、F-等干扰离子。在约0.9mol/L硫酸介质中锡与苯芴酮、溴化十六烷基三甲基铵(CTMAB)作用形成三元络合物,并在536nm处有最大吸光度,据此可实现锡的分光光度法测定。锡在0.1~1.0μg/mL范围内符合比尔定律,线性相关系数为0.999 8。方法测定下限为0.030%。对钛铁试样中锡进行测定,结果与电感耦合等离子体原子发射光谱(ICP-AES)法的测定值相吻合,相对标准偏差(RSD,n=8)小于3.0%。

铜矿、铅锌矿石样品经过盐酸、硝酸溶解,采用氢氧化铁共沉淀锡使其与铜、铅、锌分离,含锡沉淀经过氧化钠熔融,在硫酸介质中,加入硫脲-抗坏血酸-酒石酸掩蔽滞留在溶液中的干扰元素,然后用氢化物发生-原子荧光光谱法(HG-AFS)测定锡量。确定了锡与铜、铅、锌的分离条件:用氨水调节样品溶液pH 4.5;三价铁离子加入量为20 mg。方法测定范围为0.001%~1%,检出限为3μg/g。对样品中共存离子进行了干扰试验,结果表明,经过共沉淀处理后,主量元素铜、铅和锌大部分已与锡分离,不干扰锡的测定;砷、锑的干扰可通过稀释或减小取样量去除;其他元素均不干扰锡的测定。采用实验方法对实际样品进行测定,并进行加标回收试验,回收率为95%~102%。经全国不同地区8家实验室采用铜矿石、铅锌矿石样品验证,方法精密度好。

常规的国家标准方法(EDTA滴定法或分光光度法)不满足铝质量分数小于0.01%的不锈钢分析要求。试验通过新建铝元素虚拟分析通道,重建虚拟通道的分析曲线,消除不锈钢中含量较高的共存元素对于铝元素测定的干扰,利用原通道和虚拟通道分离铝元素的分析范围,使用高低标法对低含量段铝进行校正,提高了火花源原子发射光谱仪对于不锈钢中痕量铝元素的分析准确度。试验证明:上述改进对于光谱测定不锈钢中痕量铝含量的准确度有明显的提升;在不锈钢中铝质量分数小于0.001%的情况下,该方法的测定误差可以控制在0.000 5%以内且分析精密度与电感耦合等离子体原子发射光谱法(ICP-AES)的精密度相近;经统计分析,铝元素分析曲线校正后12h内不易发生漂移;生产样均匀性能够满足分析要求。因此实验方法能够满足不锈钢生产试样炉前快速分析的需要。

样品均匀性和稳定性评价是能力验证活动的重要组成部分。依据CNAS—GL03《能力验证样品均匀性和稳定性评价指南》,介绍了能力验证样品均匀性和稳定性评价的基本原理。以食用油中丁基羟茴香醚(BHA)的均匀性检验和茶叶中铜稳定性检验为例,简述了EXCEL"数据分析"工具应用于能力验证中样品均匀性和稳定性评价的使用方法,实现了实验数据的输入,得到数理统计的F值和t值。从结果可以看出:EXCEL数据处理结果与实例的计算结果是相一致的,即通过EXCEL的"数据分析"可以完成能力验证中样品均匀性和稳定性检验的工作,从而提高工作效率和统计结果的准确性。

采用偏光显微镜法测定了某未知工业矿物粉体样品中的微量石棉纤维。样品通过450℃高温热处理及酸洗过程去除大部分干扰物质,经乙醇分散后均匀沉积在玻璃片上,滴加具有固定折射率的浸渍液制成试片。在正交偏光系统下观察到粉体中存在纤维状颗粒,且纤维呈现四次平行消光特性,干涉色为白色,即具有中等折射率,插入石膏试板后根据纤维在不同象限的颜色判定其具有正延性。单偏光系统下纤维无多色性现象。在离散染色系统下经尝试不同折射率的浸渍液,观察可知纤维的折射率接近1.618 0。综合所有光学性质分析可测定样品中含有少量的透闪石石棉纤维,同时可估算出该种石棉纤维的质量分数约为1%。

The Universal Breakaway Steel Post (UBSP) was developed and evaluated to replace the existing Controlled Release Terminal (CRT) wood posts which were used in the original bullnose guardrail system. Previously, three full-scale crash tests were performed on the thrie beam bullnose barrier with UBSPs, and the UBSP was determined to be a suitable alternative for the CRT posts. However, the UBSP was modified prior to the completion of the full-scale tests, and dynamic component testing was not conducted to compare the post behaviors. Therefore, a series of nine component tests were conducted in soil to compare the weak- and strong-axis properties between the UBSPs and CRT posts. As part of the component testing, one of the weak-axis tests involving the UBSP was conducted with a reused lower section of the post; since, the original development of the UBSP recommended reuse as long as the lower section was undamaged and displaced less than 12 in. (13 mm). From the testing series, it was determined that the performance of the UBSP indicated a strong potential for these posts to be utilized in other applications. However, UBSP should first be evaluated through engineering analysis and full-scale crash testing before implementation.

In August 2010, Midwest Roadside Safety Facility (MwRSF) developed and crash tested a low-cost, energy-absorbing bridge rail for the Manual for Assessing Safety Hardware (MASH) TL-3 applications. This low-cost bridge rail was designed to be compatible with the Midwest Guardrail System (MGS) such that an approach transition would not be required between the two barriers. It was desired that the system minimize bridge deck and rail costs. As part of this project, several concepts for an energy-absorbing bridge post were developed and tested. These concepts included strong-post systems designed with plastic hinges and weak-post systems designed to bend near the attachment to the bridge deck. The final post concept incorporated S3 OE 5.7 steel sections designed to yield at their bases. These posts were located on 6 ft-3 inches on center. A W-beam section was used as the rail element and was attached to the posts with a bolt designed to break during and impact event. Two full-scale crash tests were performed according to the TL-2 impact conditions provided in MASH. The new bridge rail system successfully met all the safety performance criteria for MASH TL-2. The Texas Type T631 Bridge Rail was developed as a low-cost, energy absorbing bridge rail system for TL-2 applications. Many of the features used for the system tested at Midwest Roadside Safety Facility for TL-3 were incorporated into the design developed for this project for MASH TL-2 application. The TxDOT Type T631 Bridge Rail designed and developed for this project was evaluated under MASH TL-2.

Illinois, like many other large states, has several microclimates where temperature and rainfall can vary. These variations can affect the corrosion rates of sign and signal structures, light poles, and other highway structures. Each atmospheric zone, whether they are rural, semirural, suburban, industrial, or marine areas, may be subjected to salt fall or salt spray, which can affect metals or coatings after prolonged exposure. These highway structures are typically fabricated from weathering steel, galvanized steel, painted steel, or aluminum. Each of these metals and their coatings bear a fabrication cost and have distinct ranges of durability in different atmospheres. Rural and semi-rural atmospheres cause the least corrosion damage to metal and coated surfaces. Suburban environments generally have moderate effects, compared to industrial and saline areas, which have the most corrosive atmospheres. Weathering steels have greater durability in moderate and many industrial atmospheres compared to carbon steels, such as ASTM A36 or SAE 1020. The cost differences between ASTM A36 and ASTM A588 vs. the ASTM A710 Grade 50 steel described in this report are small. Based on data obtained from WorldSteelPrices.com, as of July 2013, the price of ASTM A36 was about $0.295 per lb compared to $0.340 per lb for ASTM A588. Because A710 has slightly higher nickel and copper contents than A588, its cost is estimated to be about $0.36 per lb, based on a metric tonne.

High hard armor steels are used on many tactical vehicles, such as the Stryker and the mine-resistant, ambush-protected vehicle. Although they provide good protection against armor-piercing threats, these steels corrode rapidly without the use of a good corrosion protective coating. Corrosion on military ground vehicles increases the infrared signal from the vehicle that the topcoat camouflage usually inhibits, making the vehicle more vulnerable to detection by the enemy. Stryker vehicles are prohibited from using hex-chrome and are currently coated without any pretreatment or conversion coating. The products demonstrated here will satisfy the hexavalent chrome prohibition while minimizing environmental impact and worker safety. This demonstration plan is designed to generate the data necessary for authorization and implementation decisions by appropriate authorities within the U.S. Department of Defense.

Metal framing and glass is a broad category of exterior enclosure systems that includes storefront, window wall, and curtain wall systems. The metal framing components are primarily aluminum, but also include stainless steel, bronze, or other architectural quality metals. Infill supported by or within the framing includes transparent or opaque materials. Transparent infill materials include insulating, laminated, or monolithic glass; polycarbonates; and thermoplastics. Opaque infill materials include architectural metals such as aluminum, stainless steel, or bronze; natural stone; fiber reinforced panels; terra cotta; or louvers.