Proficiency evaluation as a traceability link in chemical metrology

Traceability implies comparison of the results of measurements, or comparison to national or international measurement standards. One of several approaches that have been used in chemistry to provide for such comparisons is distribution of proficiency evaluation materials which have been measured by a reference laboratory. A newer approach is based on receipt and measurement at a reference laboratory of materials that have been produced and analyzed by other laboratories. Traceability concepts and approaches to realization will be described together with discussion of the relative merits of various approaches. Extension into metrological fields other than chemistry will also be explored. Received: 14 November 2000 Accepted: 11 December 2000     

What did “theory” mean to nineteenth-century chemists?

Some recent philosophers of science have argued that chemistry in the nineteenth century “largely lacked theoretical foundations, and showed little progress in supplying such foundations” until around 1900, or even later. In particular, nineteenth-century atomic theory, it is said, “played no useful part” in the crowning achievement of nineteenth-century chemistry, the powerful subdiscipline of organic chemistry. This paper offers a contrary view. The idea that chemistry only gained useful theoretical foundations when it began to merge with physics, it will be argued, is based on an implicit conception of scientific theory that is too narrow, and too exclusively oriented to the science of physics. A broader understanding of scientific theory, and one that is more appropriate to the science of chemistry, reveals the essential part that theory played in the development of chemistry in the nineteenth century. It also offers implications for our understanding of the nature of chemical theory today.     

Another scientific practice separating chemistry from physics: thought experiments

Thought experiments in the history of science display a striking asymmetry between chemistry and physics, namely that chemistry seems to lack well-known examples, whereas physics presents many famous examples. This asymmetry, I argue, is not independent data concerning the chemistry/physics distinction. The laws of chemistry such as the periodic table are incurably special, in that they make testable predictions only for a very restricted range of physical conditions in the universe which are necessarily conditioned by the contingences of chemical investigation. The argument depends on how ‚thought experiment’ is construed. Here, several recent accounts of thought experiments are surveyed to help formulate what I call ‚crucial’ thought experiments. These have a historical role in helping to judge between hypotheses in physics, but are not helpful in chemistry past or present.     

The Ontological Autonomy Of The Chemical World

In the problem of the relationship between chemistry and physics, many authors take for granted the ontological reduction of the chemical world to the world of physics. The autonomy of chemistry is usually defended on the basis of the failure of epistemological reduction: not all chemical concepts and laws can be derived from the theoretical framework of physics. The main aim of this paper is to argue that this line of argumentation is not strong enough for eliminate the idea of a hierarchical dependence of chemistry with respect to physics. The rejection of the secondary position of chemistry and the defense of the legitimacy of the philosophy of chemistry require a radically different philosophical perspective that denies not only epistemological reduction but also ontological reduction. Only on the basis of a philosophically grounded ontological pluralism it is possible to accept the ontological autonomy of the chemical world and, with this, to reverse the traditional idea of the ‘superiority’ of physics in the context of natural sciences.     

Look Better: Single Atoms in Chemistry and Single Atoms in Physics

Fostering fruitful collaboration between chemistry and physics scholars, the analysis of the differences in the practical approach to single atoms in chemistry and in physics affords a number of conceptual outcomes pointing to a more balanced and useful relationship between chemistry and physics.     

Uncertainty evaluation in proficiency testing: state-of-the-art, challenges, and perspectives

The evaluation of measurement uncertainty, and that of uncertainty statements of participating laboratories will be a challenge to be met in the coming years. The publication of ISO 17025 has led to the situation that testing laboratories should, to a certain extent, meet the same requirements regarding measurement uncertainty and traceability. As a consequence, proficiency test organizers should deal with the issues measurement uncertainty and traceability as well. Two common statistical models used in proficiency testing are revisited to explore the options to include the evaluation of the measurement uncertainty of the PTRV (proficiency test reference value). Furthermore, the use of this PTRV and its uncertainty estimate for assessing the uncertainty statements of the participants for the two models will be discussed. It is concluded that in analogy to Key Comparisons it is feasible to implement proficiency tests in such a way, that the new requirements can be met. Received: 29 September 2000 Accepted: 3 December 2000     

非高分子专业《高分子化学与物理》教学中的几点体会

高分子科学已渗透于各个领域与学科,形成了一个无法替代的交叉学科,因此,工科化学或材料相关专业纷纷开设高分子相关课程。《高分子化学与物理》作为哈尔滨工程大学材料化学专业的主干课之一,包括高分子化学和高分子物理两个侧面,其中高分子化学部分侧重高分子合成的基本理论知识,高分子物理部分则侧重于高分子的结构与性能。本文分析了高分子化学与物理的课程特点,总结了在课堂教学中采取的行之有效的措施和教学尝试,介绍了在课堂教学过程中,如何导入心理教育,提高学生的学习兴趣。     

The autonomy of chemistry: old and new problems

The autonomy of chemistry and the legitimacy of the philosophy of chemistry are usually discussed in the context of the issue of reduction of chemistry to physics, and defended making use of the failure of reductionistic claims. Until quite recent times a rather widespread viewpoint was, however, that the failure of reductionistic claims concerns actually epistemological aspect of reduction only, but the ontological reduction of chemistry to physics cannot be denied. The new problems of the autonomy of chemistry in the context of reductionism seem to be ontological and metaphysical. In the present paper it is argued that there is no need for some kind of metaphysical-ontological underpinning for rejection of the secondary positions of chemistry and philosophy of chemistry with respect to physics and philosophy of physics. The issue can be elucidated in terms of the philosophy of science accepting practical realism (also known by other names).     

应用化学专业《高分子物理》教学的几点体会

高分子科学已在各个学科广泛渗透,鉴于此,《高分子物理》被设置为天津大学理学院应用化学专业的专业基础课。但相对于高分子专业,应用化学专业《高分子物理》课程存在着课时少、无实验环节的不足。本文介绍了作者在应用化学专业《高分子物理》教学中采取的一些措施,如依据专业特点精选教学内容,弱化次要内容和公式推导;演示实验、实物教学、多媒体教学和问题驱动教学相结合;加强理论与应用的联系;将高分子学科史知识和人文精神融合到课堂中等。     

Linking chemistry with physics: arguments and counterarguments

The many-faced relationship between chemistry and physics is one of the most discussed topics in the philosophy of chemistry. In his recent book Reducing Chemistry to Physics. Limits, Models, Consequences, Hinne Hettema (Reducing chemistry to physics. Limits, models, consequences, Rijksuniversiteit Groningen, Groningen, 2012) conceives this relationship as a reduction link, and devotes his work to defend this position on the basis of a “naturalized” concept of reduction. In the present paper I critically review three kinds of issues stemming from Hettema’s argumentation: philosophical, scientific and methodological.     

FAIR@Germany

The proposed international Facility for Antiproton and Ion Research (FAIR) at GSI-Darmstadt, will be a source of exotic radionuclidic beam and is expected to be operational in 2016. The facility will deliver 2 GeV/u to 45 GeV/u beam covering the entire range of the periodic table with the intensities three orders of magnitude higher than that available anywhere in the world today. This facility will serve all areas of fundamental sciences including nuclear physics, physics at extreme density conditions like neutron stars, plasma and laser physics, hadron physics and applied areas in chemistry, biology and material sciences. In this article, we discuss briefly the FAIR facility, with special emphasis on Indian participation.     

Economy of proficiency testing: reference versus consensus values

Many proficiency tests are operated with a consensus value derived from the participants’ results. Apart from technical issues, one of the reasons often mentioned is that proficiency tests operated with consensus values would be cheaper than those using reference values obtained from a priori characterisation measurements. The economy of a proficiency test must of course be balanced by the need of the participants, and the quality of the comparison in general. The proficiency tests selected in this study had both a reference value and a consensus value, one of which was used for assessing the performance of the participating laboratories. In this work, both a technical and an economical assessment of how the comparisons were operated is made. From the evaluation, it follows that usually the use of consensus values does not necessarily reduce the costs of a proficiency test. However, frequently it may be observed that the quality of the assessment of the laboratories is better with a reference value. Received: 11 October 2000 Accepted: 3 January 2001     

The practice of proficiency testing in China

This paper briefly summarises the current situation for proficiency testing (PT) in China, outlines the policy for PT of China’s national accreditation committee for laboratories (CNACL), and exemplifies activities of the CNACL’s metal working group. Received: 9 December 2000 Accepted: 14 December 2000     

Reference materials and certified reference materials for water and food microbiology

Summary The concept of Certified Reference Materials (CRMs) for the verification of the accuracy of analytical methods and the traceability of the results to a CRM, is well accepted in chemistry. The use of Reference Materials (RMs) for intra-laboratory quality control schemes or for round-robin and proficiency testing is well established and follows from certain norms (ISO 9000 and EN 45000 series). For microbiology such concepts have not been fully defined and RMs are only rarely used. CRMs do not exist. To fill this gap the Commission of the European Community, through the BCR programme, has launched projects in collaboration with the RIVM (National Institute of Public Health and Environmental Protection) in Bilthoven (NL). Following fundamental considerations and feasibility studies, several intercomparisons have been held using selected laboratories working with food or water microbiology. Various microbiological strains have been subject of studies: Salmonella typhimurium, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus for food, Escherichia coli, Enterococcus faecium, Enterobacter cloacae and Staphylococcus warneri for water. To produce materials for interlaboratory studies, a set of milk powders was prepared by spray-drying. Separate portions were contaminated with one of the strains mentioned. The materials were then encapsuled in gelatine. It has been demonstrated that if protected in milk powder matrices, bacteria maintain the ability to be revived, but do not multiply. The modes of evaluation of the results for homogeneity and stability differ from those commonly used in chemistry.     

ER-BOC calculations of crystal bulk properties from smallest-cluster models

Ab initio calculation of bulk properties of crystals with a high accuracy, which is a long-time goal of solid chemistry and physics, is still difficult and expensive because a large cluster is required as a crystal structure model. This article proposes a model based on density functional theory (DFT) quantum chemistry calculations and the assumption that the bond order of a given atom with its nearest atoms in a compound is conserved over the entire range from its diatomic molecules to clusters and further to crystals. This entire range bond order conservation (ER-BOC) provides an effective way to correlate bulk properties of crystals with those of the corresponding molecules and small clusters. By combining this ER-BOC principle with hybrid DFT quantum chemistry calculations, accurate predictions of the bulk bond lengths of a crystal can be made using calculations on small clusters.     

Early impact of quantum physics on chemistry: George Hevesy’s work on rare earth elements and Michael Polanyi’s absorption theory

After Heitler and London published their pioneering work on the application of quantum mechanics to chemistry in 1927, it became an almost unquestioned dogma that chemistry would soon disappear as a discipline of its own rights. Reductionism felt victorious in the hope of analytically describing the chemical bond and the structure of molecules. The old quantum theory has already produced a widely applied model for the structure of atoms and the explanation of the periodic system. This paper will show two examples of the entry of quantum physics into more classical fields of chemistry: inorganic chemistry and physical chemistry. Due to their professional networking, George Hevesy and Michael Polanyi found their ways to Niels Bohr and Fritz London, respectively, to cooperate in solving together some problems of classical chemistry. Their works on rare earth elements and adsorption theory throws light to the application of quantum physics outside the reductionist areas. They support the heuristic and persuasive value of quantum thinking in the 1920–1930s. Looking at Polanyi’s later oeuvre, his experience with adsorption theory could be a starting point of his non-justificationist philosophy.     

Stuff versus individuals

The general question to be considered in this paper points to the nature of the world described by chemistry: what is macro-chemical ontology like? In particular, we want to identify the ontological categories that underlie chemical discourse and chemical practice. This is not an easy task, because modern Western metaphysics was strongly modeled by theoretical physics. For this reason, we attempt to answer our question by contrasting macro-chemical ontology with the mainstream ontology of physics and of traditional metaphysics. In particular, we introduce the distinction between stuff-ontology, proper of chemistry, and individual-ontology, proper of physics. These two ontologies differ from each other in the basic categories of their own structures. On this basis, we characterize individual-ontology in such a way that the features of stuff-ontology will arise by contrast with it.     

On-wire conversion chemistry: engineering solid-state complexity into striped metal nanowires using solution chemistry reactions

Multisegment template-grown metal nanowires have become important one-dimensional materials for a variety of applications in chemistry, physics, engineering, biology, and medicine. Segmented nanowires are traditionally fabricated in anodic alumina membranes using electrodeposition, and this technique is applicable to a range of metals, alloys, and semiconductors. Here we report an alternative and simple solution chemistry strategy for incorporating multimetal components of controllable length and composition into template-grown metal nanowires. By reacting membrane-confined nanowires with metal salt solutions under reducing conditions, site-specific diffusion occurs to convert one or both nanowire tips or the entire nanowire into a variety of multimetal phases. Platinum-based intermetallic compounds were chosen as targets for demonstrating the feasibility of the on-wire conversion chemistry.     

A model to set measurement quality objectives and to establish measurement uncertainty expectations in analytical chemistry laboratories using ASTM proficiency test data

A model is presented that correlates historical proficiency test data as the log of interlaboratory standard deviations versus the log of analyte concentrations, independent of analyte (measurand) or matrix. Analytical chemistry laboratories can use this model to set their internal measurement quality objectives and to apply the uncertainty budget process to assign the maximum allowable variation in each major step in their bias-free measurement systems. Laboratories that are compliant with this model are able to pass future proficiency tests and demonstrate competence to laboratory clients and ISO 17025 accreditation bodies. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/ 10.1007/s007690100398-y. Received: 31 March 2001 Accepted: 11 September 2001     

Applied radiation research around a 15 MeV high-average-power linac

The Department of Subatomic and Radiation Physics of the University Gent is equipped with a 15 MeV 20 kW linear electron accelerator (linac) facility. In its present configuration the accelerator is used as a multipurpose apparatus for research in the fields of polymer chemistry, biomedical materials, medicine, food technology, dosimetry, solid state physics, agriculture and nuclear and radiation physics. We present an overview of both the various research projects around our linac facility involving radiation chemistry and physics and the specialised technologies facilitating this research.