In this paper, the application of instrumented indentation devices to the measurement of the elastic modulus of polymeric materials is reviewed. This review includes a summary of traditional analyses of load‐penetration data and a discussion of associated uncertainties. Also, the use of scanning probe microscopes to measure the nanoscale mechanical response of polymers is discussed, particularly with regard to the associated limitations. The application of these methods to polymers often leads to measurements of elastic modulus that are somewhat high relative to bulk measurements with potentially artificial trends in modulus as a function of penetration depth. Also, power law fits to indentation unloading curves are often a poor representation of the actual data, and the power law exponents tend to fall outside the theoretical range. These problems are likely caused by viscoelasticity, the effects of which have only been studied recently. Advancement of nanoindentation testing toward quantitative characterization of polymer properties will require material‐independent calibration procedures, polymer reference materials, advances in instrumentation, and new testing and analysis procedures that account for viscoelastic and viscoplastic polymer behavior.

To improve the effectiveness of calcium phosphate cement (CPC), we have developed a method to seed osteoblasts into the cement. CPC powder is mixed with water to form a paste that can be shaped to fit a bone defect in situ. The paste hardens in 30 min, reacts to form hydroxyapatite, and is replaced with new bone. Reacted CPC is biocompatible but unreacted CPC paste was found to have toxic effects when placed on cell monolayers (MC3T3-E1 cells). In contrast, when cells were indirectly exposed to CPC paste using a porous membrane or by placing a coverslip containing adherent cells onto a bed of CPC paste, the unreacted CPC was nontoxic. These results suggested that gel encapsulation of the cells might protect them from the CPC paste. Thus, cells were encapsulated in alginate beads (3.6-mm diameter), mixed with CPC paste, and incubated overnight. Both vital staining (calcein-AM and ethidium homodimer-1) and the Wst-1 assay (measures dehydrogenase activity) showed that cell survival in alginate beads that were mixed with CPC was similar to survival in untreated control beads. These results suggest that gel encapsulation could be used as a mechanism to protect cells for seeding into CPC.

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH), has developed a Standard Reference Material (SRM) to support technology development in metabolomics research. SRM 1950 Metabolites in Human Plasma is intended to have metabolite concentrations that are representative of those found in adult human plasma. The plasma used in the preparation of SRM 1950 was collected from both male and female donors, and donor ethnicity targets were selected based upon the ethnic makeup of the U.S. population. Metabolomics research is diverse in terms of both instrumentation and scientific goals. This SRM was designed to apply broadly to the field, not toward specific applications. Therefore, concentrations of approximately 100 analytes, including amino acids, fatty acids, trace elements, vitamins, hormones, selenoproteins, clinical markers, and perfluorinated compounds (PFCs), were determined. Value assignment measurements were performed by NIST and the Centers for Disease Control and Prevention (CDC). SRM 1950 is the first reference material developed specifically for metabolomics research.

The problem of determining a consensus value and its uncertainty from the results of multiple methods or laboratories is discussed. Desirable criteria of a solution are presented. A solution motivated by the ISO Guide to the Expression of Uncertainty in Measurement (ISO GUM) is introduced and applied in a detailed worked example. A Bayesian hierarchical model motivated by the proposed solution is presented and compared to the solution.

EXECUTIVE SUMMARYThe 3 Megawatt Heat Release Rate Facility (3MWHRRF) was developed at the National Institute of Standards and Technology (NIST) as a first step toward having broad capabilities for making quantitative large scale fire measurements. Such capabilities will be used at NIST to validate fire models and to develop sub-grid models. It will also serve to provide a data base for studying a broader range of fire phenomena, and to address issues related to material acceptance and fire codes. An equally important objective is to provide templates for use by other laboratories including commercial testing facilities to improve the quality of their data.Heat release is the result of the combustion of a fuel with the oxygen in air. The fuels of primary interest are those found in constructed facilities and include wood, plastics, foam materials used in furnishings (such as polyurethane), wire insulation (such as polyvinyl chloride), and carpet materials (such as nylon).The rate at which heat is released is the single most important quantity in terms of fire safety. Thus it is important that this measurement be made in a quantitative manner. It is a key predictor of the hazard of a fire, directly related to the rate at which heat and toxic gases build up in a compartment or the rate at which they are driven into more remote spaces. Heat release rates on the order of 1 MW to 3 MW are typical in a room that is flashed over or from a single large object such as a bed or sofa.It is important that heat release rate measurements be made accurately because fire regulations are frequently based on peak rates of heat release. Testing laboratories must be confident that the objects tested pass the required regulation and manufacturers need accurate information in defining the fire safety characteristics of their products. A second need for accurate heat release rate data is for the development of quantitative models for predicting heat release rate. In comparing a fire experiment and a model prediction, it is essential that the heat release rate measurement have an estimated uncertainty.The 3MWHRRF developed at NIST meets the needs described above for objects that can be placed under the 6 m × 6 m hood, which is approximately 4 m above the floor, or for enclosures whose effluent can all be directed into the hood. It is capable of measuring heat release rates in the range of 0.10 MW to 3.0 MW including brief peaks as high as 5 MW. As documented in this publication, the expanded uncertainty (95 % confidence interval) is 11 % of the heat release rate for fire sizes larger than 400 kW. The response time of the system is such that it can accurately resolve dynamic heat release rate events of 15 seconds or more.This document is intended to serve as a description of the NIST 3 Megawatt Heat Release Rate Facility and as an operations manual. It is also intended to serve as a general guide for implementing, operating and maintaining quality control of similar quantitative large scale heat release rate measurement facilities. The m...