The impact of measurement uncertainty on the producer’s and user’s risks, on classification and conformity assessment: an example based on tests on some construction products

The reliability of test results and subsequent classification statements or product certification depend on the variability of the product’s properties and on the validity of the test procedures used. With an emphasis on measurement uncertainty, producer’s and user’s risks as well as probabilities of conformance, conformity and classification are calculated exemplarily for two requirements for mineral aggregates used in construction. An important methodological basis is an international draft document on measurement uncertainty in conformity assessment. The mathematical instruments given are applied and further developed to a risk scenario for product classification. The results from a classification point of view show that the reliability of test results for acid-soluble sulphates is mostly acceptable and both the producer’s and user’s risks are quite small. In contrast, the magnesium sulphate index test produces results which are hardly usable for classification and certification purposes or for risk management in production. Product certification bodies should generally have an appropriate approach when dealing with results where precision data are poor.     

Theoretical Studies of Water’s and Methanol’s Effects on Alcoholysis of N-Benzyl-3-oxo-β-sultam

The mechanisms about the water’s and methanol’s effects on the alcoholysis of N-benzyl-3-oxo-β-sultam together with their differences have been studied by using density func- tional theory at the B3LYP/6-31G* level. The results, in comparison with a previous study on the relative reaction without the assistance of water and methanol, show that the added water or methanol can remarkably reduce the energy barrier of alcoholysis reaction of N-benzyl-3-oxo- β-sultam and the most favorite pathway is the breaking of C–N bond instead of S–N. It is also found that the reaction energy barrier of methanol-assisted alcoholysis is a little higher than that of the water-assisted one.     

Forecasting China’s natural gas consumption based on a combination model

Ensuring a sufficient energy supply is essential to a country. Natural gas constitutes a vital part in energy supply and therefore forecasting natural gas consumption reliably and accurately is an essential part of a country's energy policy. Over the years, studies have shown that a combinative model gives better projected results compared to a single model. In this study, we used Polynomial Curve and Moving Average Combination Projection (PCMACP) model to estimate the future natural gas consumption in China from 2009 to 2015. The new proposed PCMACP model shows more reliable and accurate results: its Mean Absolute Percentage Error (MAPE) is less than those of any previous models within the investigated range. According to the PCMACP model, the average annual growth rate will increase for the next 7 years and the amount of natural gas consumption will reach 171600 million cubic meters in 2015 in China.     

Metabolomic approach to Alzheimer’s disease diagnosis based on mass spectrometry

Alzheimer??s disease is the most common neurodegenerative disease, but there is still no cure and early diagnosis remains very difficult. For this reason, the discovery of new biomarkers is of great importance. The application of metabolomics is emerging in this field, based on the use of mass spectrometry as a technique of analysis. In this work, blood serum samples (from Alzheimer??s disease patients and healthy controls) were analysed by mass spectrometry in order to search for potential metabolomic biomarkers. The application of multivariate statistical tools (PLS-DA) enabled us to discriminate between groups. In addition, some phosphatidylcholine compounds were identified as markers of the disease.     

Influence of luminol on the chemiluminescence intensity in Fenton’s reaction

The kinetics of Fe⁺² oxidation and buildup of luminol oxidation products during Fenton’s reaction at pH 2 have been calculated. The characteristics of the process in neutral (pH 6) and alkaline (pH 12) media have been evaluated. The calculation results have been compared with experimental data on the yield of chemiluminescence induced by Fenton’s reagent and luminol. It has been shown that trivalent iron ions suppress the luminol emission. The presence of iron or another transition metal in the sample can significantly reduce the chemiluminescence quantum yield after luminol introduction if.     

Honda’s thermobalance

Kotaro Honda (2/23/1870–2/12/1954) graduated from the Department of Physics, Tokyo Imperial University in 1897. Between 1907 and 1911, he stayed in Europe, and spent the majority of his time at Göttingen University to study physical metallurgy under Professor Gustav Tammann. In 1911, he returned to Japan and was nominated professor of physics at Tohoku Imperial University, Sendai. An university-affiliated institute for research on iron and steel was established on a permanent basis in 1919, and the institute developed to the Research Institute for Iron, Steel, and Other Metals (RIISOM, KINKEN in Japanese) in 1922. Professor Honda served as the Director of the Institute until 1933. The RIISOM was reorganized as a national collaborative research institute named Institute for Materials Research in 2001. Professor Honda and his colleagues achieved distinguished research works of physical metallurgy, in which thermoanalytical techniques such as differential thermal analysis (DTA), thermodilatometry and thermomagnetometry were utilized effectively. Professor Honda also played an important role in the field of thermogravimetry (TG) by means of the first development of the thermobalance. In the present paper, Honda’s original thermobalance, various modifications carried out by his school, the commercialized Honda’s thermobalance and other related matters are briefly summarized.     

The influence of the dialkylphenyltolane’s difluorosubstitution on mesomorphic and dielectric properties

The synthesis of variously difluoro-substituted 4-butyl-4?-[2-(4-butylphenyl)ethynyl]-1,1?-biphenyls is presented and discussed. Molecular correlations between positions of fluorine atoms at phenyltolane core and mesomorphic, dielectric properties of newly synthesised liquid crystals (LC) have been drawn and discussed. New LC molecules exhibit a wide range of nematic phase and are promising components of liquid crystalline mixtures. They were characterised by ¹H NMR spectroscopy and mass spectrometry analysis. Phase transition temperatures, enthalpies, mesomorphic and dielectric properties were confirmed by a polarising optical microscopy, differential scanning calorimetry and dielectric spectroscopy.     

What’s CUR≟

The chapter of the student affiliates of the American Chemical Society at the University of Tennessee at Martin has won three commendable and eighteen consecutive outstanding ratings, the most consecutive ratings of any student affiliate chapter, from the Society Committee on Education of the American Chemical Society. The activities of the chapter involve a great deal of pedagogic or literal chemistry, that is the members learn and communicate several aspects of chemistry from the chapter programs. In addition, a special chemistry or camaraderie results when members prepare for and participate in the various club projects and activities. This article briefly describes specific activities of UTM student affiliates that help to develop both the literal and the special chemistry among members. Finally, The High School Science Bowl, which is a most electrifying and rejuvenating activity, is described in greater detail for the information of other chemistry clubs.     

Millikan’s Oil-Drop Experiments

Millikans oil-drop experiments are justly regarded as a major contribution to twentieth-century physics [1, 2]. They established the quantization of electric charge, the existence of a fundamental unit of charge, and also measured that unit of charge precisely. As Gullstrand remarked in his Nobel Prize presentation speech, Millikans aim was to prove that electricity really has the atomic structure, which, on the base of theoretical evidence, it was supposed to have.... By a brilliant method of investigation and by extraordinarily exact experimental technique Millikan reached his goal.... Even leaving out of consideration the fact that Millikan has proved by these researches that electricity consists of equal units, his exact evaluation of the unit has done physics an inestimable service, as it enables us to calculate with a higher degree of exactitude a large number of the most important physical constants [3].¹     

Today’s and tomorrow’s bio-based bulk chemicals from white biotechnology

Little information is yet available on the economic viability of the production of bio-based bulk chemicals and intermediates from white biotechnology (WB). This paper details a methodology to systematically evaluate the techno-economic prospects of present and future production routes of bio-based bulk chemicals produced with WB. Current and future technology routes are evaluated for 15 products assuming prices of fermentable sugar between 70 euro/t and 400 euro/t and crude oil prices of US $25/barrel and US $50/barrel. The results are compared to current technology routes of petrochemical equivalents. For current state-of-the-art WB processes and a crude oil price of US $25/barrel, WB-based ethanol, 1,3-propanediol, polytrimethylene terephthalate and succinic acid are economically viable. Only three WB products are economically not viable for future technology: acetic acid, ethylene and PLA. Future-technology ethylene and PLA become economically viable for a higher crude oil price (US $50/barrel). Production costs plus profits of WB products decrease by 20-50% when changing from current to future technology for a crude oil price of US $25 per barrel and across all sugar prices. Technological progress in WB can thus contribute significantly to improved economic viability of WB products. A large-scale introduction of WB-based production of economically viable bulk chemicals would therefore be desirable if the environmental impacts are smaller than those of current petrochemical production routes.     

V-shaped Schiff’s base liquid crystals based on resorcinol: synthesis and characterisation

ABSTRACT

This paper designed and synthesised a series of V-shaped liquid crystal molecules (X-SBA_nE) with resorcinol as the core and Schiff base as the mesogenic arms (X-SBAA_n). The effects of polarity of terminal groups (X=-CH₃O,-CH₃,-Cl) and length of flexible chain (n = 4,6,8) on mesogenic ranges were discussed. The chemical structure of X-SBAA_n and X-SBA_nE was studied using FT-IR and ¹H-NMR while their thermal behaviour and mesogenic ranges were investigated via differential scanning calorimetry (DSC) and polarising optical microscopy (POM). The results indicated that X-SBAA_n containing OCH₃ and Cl substituents exhibited mesophase except for the analogue having CH₃ substituent which was found to be non-mesogenic. All of the synthesised X-SBA_nE had liquid crystal properties and exhibited nematic phases in heating and cooling. The length of the flexible spacers and terminal groups significantly influenced their mesogenic ranges.     

Characterization of Biosorption Process of Acid Orange 7 on Waste Brewery’s Yeast

The use of cheap, high-efficiency, and ecofriendly adsorbent has been studied as an alternative way for the removal of dyes from wastewater. This paper investigated the use of waste brewery’s yeast for the removal of acid orange 7 from aqueous solution. The optimum removal of acid orange 7 was found to be 3.561 mg/g at pH 2.0, 10 mg/L initial concentration and 303 K. The kinetic studies indicated that the biosorption process of acid orange 7 agreed well with the pseudo-second-order model. The external diffusion is the rate-controlling step of the initial fast adsorption (<20 min) and then the intraparticle diffusion dominated the mass transfer process. Langmuir, Freundlich, and Dubinin–Radushkevich models were applied to describe the biosorption isotherm of acid orange 7 by waste brewery’s yeast. Langmuir isotherm model fits the equilibrium data, at all the studied temperatures, better than the other isotherm models which indicates monolayer dye biosorption process. The highest monolayer biosorption capacity was found to be 2.27 × 10⁻³ mol/g at 303 K. The calculated thermodynamic parameters (ΔG, ΔS, ΔH) showed the biosorption process to be spontaneous and exothermic in nature. Amine or amino, amide, carboxyl, phosphate groups are responsible for the dyes biosorption based on the result of Fourier transform infrared analysis.     

A critique of Weisberg’s view on the periodic table and some speculations on the nature of classifications

This article carefully analyzes a recent paper by Weisberg in which it is claimed that when Mendeleev discovered the periodic table he was not working as a modeler but instead as a theorist. I argue that Weisberg is mistaken in several respects and that the periodic table should be regarded as a classification, not as a theory. In the second part of the article an attempt is made to elevate the status of classifications by suggesting that they provide a form of ‘side-ways explanation’.     

Igor’ Vladimirovich Pletnev’s 50th birthday

Chronicle

Igor’ Vladimirovich Pletnev’s 50th birthday     

Application of Young’s equation to two immiscible liquids resting on a solid substrate

The geometry of two immiscible liquid drops (water and mercury) resting on a solid substrate is reported. The problem under investigation is a very simple situation of a non-miscible two-phase liquid system which is properly documented. The simple experimental observation of water micro drop on top of a mercury drop on polypropylene substrate is discussed. The static situation of the drops is explored, and a new equation is derived for such situation by applying Young’s equation to the contact angles. The obtained equation simply represents the additive summation of Young equations for two independent drops, and may be applied for the case when the interfaces of two drops are close to each other and hence interact. The forces at the contact lines of each drop are treated separately as well as in correlation. This paper shows a schematic representation of two-liquid phase contact angle system. The value of this work may be appreciated from a pedagogical point of view.     

Effect of the direction of the earth’s magnetic field lines on corrosive wear

In this work, the effect of the direction of the Earth’s magnetic field lines on the corrosive wear of steel samples in an aggressive medium was studied, and a study algorithm and a data processing algorithm were described.