Expression for the Accuracy of Measuring Instruments in Accordance with the Concept of Uncertainty of Measurements

The present article considers the need to express the accuracy of both standard and working measuring instruments by a standard uncertainty estimated in accordance with type A or type B, or by the combined uncertainty, the permissible uncertainty, or the permissible uncertainty for the confidence level P.     

Associations between driving under the influence of alcohol or drugs,speeding and seatbelt use among fatally injured car drivers in Norway

Since 2005, all fatal road traffic crashes in Norway have been analyzed in-depth by multidisciplinary investigation teams organized by the Norwegian Public Roads Administration (NPRA). During the period 2005–2010, 608 drivers of cars or vans were killed in road traffic crashes. Blood samples were collected from 372 (61%) of the drivers and analyzed for alcohol and a large number of psychoactive drugs at the Norwegian Institute of Public Health (NIPH). After coupling the analytical results with the NPRA crash database, 369 drivers with a fatal outcome were identified and included. Alcohol or drug concentrations in blood above the legal limits were found in 39.8% of the drivers who were investigated for alcohol or drug impairment; 33.9% had blood alcohol concentrations above 0.5 g/L or concentrations of drugs above the equivalent Norwegian legal impairment limits or concentrations of amphetamines above 200 μg/L. Among drivers with a fatal outcome who had been impaired by alcohol or drugs, 64.6% were unbelted and 71.7% were speeding when the crash occurred; whereas 24.2% and 33.2% of the sober drivers were unbelted or speeding, respectively. Statistically significant associations were found between impairment by alcohol or amphetamines and driving unbelted or speeding. Excessive speeding is one of the main reasons for road traffic crashes and together with being unbelted the main reasons for a fatal outcome. This behavior might in many cases be due to increased risk-taking or negligence of safety measures as a result of alcohol or drug use.     

Bayesian Control Chart for Nonconformities

The c‐chart or the control chart for nonconformities is designed for the case where one deals with the number of defects or nonconformities observed. A control chart can be developed for the total or average number of nonconformities per unit, which is well modeled by the Poisson distribution. In this paper the c‐chart will be studied, where the usual operation of the c‐chart will be extended by introducing a Bayesian approach for the c‐chart. Control chart limits, average run lengths, and false alarm rates will be determined by using a Bayesian method. These results will be compared with the results obtained when using the classical (frequentist) method. Copyright © 2014 John Wiley & Sons, Ltd.     

The classification of biomedical journals by research level

A new method of classification of biomedical research journals by research level (RL) into clinical or basic, or somewhere in between, is described that updates the system developed by CHI Research Inc. nearly 30 years ago. It is based on counting articles that have one of about 100 “clinical” title words, or one of a similar number of “basic” title words, or both. It allows over 3000 journals in the Science Citation Index (or other databases) to be classified rapidly and transparently, for changes in their research level with time, and for many individual papers in “mixed” journals to be categorised as clinical or basic. This revised version was published online in June 2006 with corrections to the Cover Date.     

Design of high sorbent pectin/CaCO3 composites tuned by pectin characteristics and carbonate source

Five pectin samples – which differ by the methylation degree and/or amide content – were used to prepare inorganic/organic composites by CaCO₃ mineralization from supersaturated solutions. The pectin chemical structure and concentration could control the composite superstructure by induction or orientation of crystal growth. The inorganic materials may also control CaCO₃ polymorphism and morphologies and therefore different carbonate sources, such as Na₂CO₃, diethylcarbonate or ammonium carbonates, were used as modulators for crystal growth. The morphology of the new CaCO₃/pectin composites was investigated by SEM and the polymorphs content by X-ray diffraction, as compared to bare CaCO₃ samples prepared in similar conditions. The composites were tested as sorbents for Cu(II) and Ni(II) ions.     

Least-squares Trefftz-type elements for the Helmholtz equation

Trefftz-type elements, or T-elements, are finite elements the internal field of which fulfills the governing differential equations of the problem a priori whereas the prescribed boundary conditions and the interelement continuity must be enforced by some suitable method. In this paper, the relevant matching is achieved by means of a least-squares procedure. The so-called ‘frameless’ or least-squares T-elements for Helmholtz's equation (related to the scattering of waves by offshore structures) in 2-D are developed and studied. The required accuracy of the solution can be obtained by increasing the number of either the subdomains or T-functions, which can be regarded as the h- or p-type approach, respectively. Convergence studies are performed with much attention to the use of special purpose elements for a doubly connected domain with a circular hole and for an angular corner subdomain. The most attractive features of the presented formulation are its simplicity and robustness. The matrix of the resulting linear system is always Hermitian and positive definite. © 1998 John Wiley & Sons, Ltd.     

Liposomes containing drug and cyclodextrin prepared by the one-step spray-drying method

The one-step spray-drying method was applied in the preparation of liposomes containing drug and cyclodextrin (CD). Spray-dried lecithin liposomes, entrapping metronidazole or verapamil alone or together with hydroxypropyl-β-cyclodextrin (HPβCD), were characterized for morphology, size distribution, and drug entrapment efficiency. The main factor influencing the liposomal size was the volume of aqueous medium used for hydration of the spray-dried product. No differences in size or entrapment between liposomes prepared by immediate hydration of dried powder or by hydration after 1 year of powder storage at 4°C were observed. All liposomes were tested for their serum stability. The most stable liposomes (still retaining about 10% of the originally entrapped drug even after 24 hr incubation with serum) were liposomes prepared by the direct spray-drying of the mixture of lipid, drug, and HPβCD.     

A coincidence system for radionuclide standardization using surface barrier detectors

A system for the standardization of alpha-gamma or electron-X radionuclide emitters is described. The system consists of one or two surface barrier detectors for alpha or electron detection which are coupled to thin-window NaI(Tl) crystals suitable for low-energy X- or gamma-ray detection. The performance of the system has been verified by the standardization of ²⁴¹Am, ¹³⁷Cs and ¹⁰⁹Cd solutions. The activity has been obtained using the extrapolation method applied to the 4π -γ and 2π e-X coincidence techniques. The surface barrier detection efficiency was varied by placing absorbers over the radioactive source or by changing the source-to-detector distance. The results were compared to those obtained using conventional absolute systems based on gas-flow and pressurized 4π proportional counters, or using radioactive solutions standardized in international comparisons sponsored by the Bureau International des Poids et Mesures, France. The expected and measured activities agreed within the experimental uncertainties, which were: 0.2% for ²⁴¹Am, 0.7% for ¹³⁷Cs and 0.6% for ¹⁰⁹Cd.     

Verschiebungsvektoren für den Vergleich von Av-T-Kurven

Shift vectors for the comparison of C_v-T-curves It is shown in this paper that a shift in the C_v-T-curves caused by mechanical or thermal treatment, or by irradiation with particles of high energy can be better described by a shift vector given by the inversion points of a functionally determined curve than with the currently used empirical criteria. Moreover, the shift of a whole curve can be described by a vector whose components are the shifts of all parameters used for the calculation of the curve. The resulting vector of a C_v-T-curve may, for instance, be connected functionally with the neutron fluence. This makes it possible to compute shift vectors.     

Numerical solution of singular integral equations for planar problems in the theory of elasticity for a body with corner points at the edges

Summary Singular integral equations have been used to derive numerical solutions for planar cases in the theory of elasticity for bodies bounded by piecewise-smooth edges with allowance for the stress singularities at the corner points. Problems are considered on tension and shear for an infinite plate weakened by a semicircular hole or by a smooth curvilinear crack or a two-part kinked one. Values are given for the stress-intensity coefficients at the corner points and at the crack vertices.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 25, No. 3, pp. 68–75, May–June, 1989.     

Electrical and mechanical properties of electrically conductive polyethersulfone composites

Electrically conductive polyethersulphone (pes) composites containing carbon fibres, nickel fibres, stainless steel fibres or aluminium flakes at various volume fractions up to 40% were fabricated and tested. For electromagnetic interference (emi) shielding effectiveness > 50 dB, the minimum filler volume fraction was 40% for carbon fibres of length 200 or 400 μm, 20% for nickel or stainless steel fibres, and 30% for aluminium flakes. The tensile strength first increased and then decreased with increasing filler content, such that the highest tensile strength occurred at 30 volume% (vol%) for carbon fibres (of length 200 or 400 μm) as the filler and at 10 vol% for nickel or stainless steel fibres. However, for carbon fibres (of length 100 μm) and aluminium flakes, the tensile strength increases up to at least 40 vol%. The best overall performance was provided by aluminium flakes at 40 vol%; the resistivity was 7 × 10⁻⁵ Ω cm, the emi shielding effectiveness was > 50 dB and tensile strength was 67 MPa. The resistivity of the aluminium flake composites was not affected by heating in air at 140°C for up to at least 144 h.     

Analysing the development of road safety using demographic data

The purpose of this paper is to show that time series analyses of road safety and risk can be improved by using demographic data. We demonstrate that the distance travelled by drivers or riders of a certain age reflects the fluctuations over the years of the number of people of that age within the population. We further demonstrate that the change over time of per capita distance travelled, i.e. distance travelled per person, is often less subject to stochastic fluctuations, and therefore more smooth than the total distance travelled for drivers of that age. This smoothness is used to obtain forecasts of distance travelled, or to average out year-to-year fluctuations of data of distance travelled. Analysis of such data stratified by age group, gender or both reveals that, for most travel modes, per capita distance travelled is to a large extent constant or slowly changing over time. The consequences for the evaluation of risk, i.e. casualties per distance travelled, with and without the use of population data, are explored. Dutch data are used to illustrate the model concept.     

Flame pyrolysis – a preparation route for ultrafine pure γ-Fe2O3 powders and the control of their particle size and properties

Highly dispersed γ-Fe2O3 powders with particle sizes down to 5 nm were directly synthesized by combustion of solutions of iron pentacarbonyl or iron(III) acetylacetonate in toluene in an oxyhydrogen flame. The particle size as well as other properties of the obtained powders can be controlled simply by varying the iron concentration in the starting solutions. Phase composition, morphological and magnetic properties of the powders were studied. The reasons for the formation of γ-Fe2O3 are discussed by means of structure–chemical/kinetic considerations. The materials are interesting as recording materials, or ferrofluids, or for colour imaging and bioprocessing. This revised version was published online in November 2006 with corrections to the Cover Date.     

Maximizing survivability of vulnerable weighted voting system

The weighted voting system (WVS) studied consists of N units that each provide a binary decision (0 or 1) or abstain from voting. Each unit has its own individual weight. System output is 1 if the cumulative weight of all 1-opting units is at least a pre-specified fraction τ of the cumulative weight of all non-abstaining units. Otherwise system output is 0.For a system consisting of voting units (VUs) with given reliability characteristics one can maximize the entire system reliability by choosing proper unit weights and threshold values τ.When a system operates in battle conditions or is affected by a corrosive medium or other hostile environment, its survivability (the ability to tolerate intentional attacks or accidental failures or errors) is becoming especially important. One of the ways to enhance voting system survivability is to separate its VUs.We formulate the problem of maximizing survivability of WVS by proper choice of unit weights and system threshold value and by unit separation.An algorithm for solving the problem is based on using a universal generating function technique for evaluating system survivability. A genetic algorithm is used as the optimization tool. Examples are presented.     

OTHER INCOME PATTERNS AND STOCHASTIC CONSIDERATIONS IN ECONOMIC DECISION MAKING

The purpose of this paper is two fold: first to provide a method for evaluating projects which have an income pattern describable by a polynomial function of time, and to provide a means for evaluating projects which exhibit a yearly growth or decline in earnings while maintaining the ability to account for the time pattern of earnings, and second to bring forth an assessment technique which will reflect the possibility of attaining various levels of income for each of the periods of interest. Methods utilized in developing the various models are based on the concept of dynamic return.

The future and present worths of a project are calculated for the case in which the earnings follow a pattern of the form given by either Ct^m or C(l — t)^m. Two types of growth patterns, geometric, in which earnings increase or decline by a fixed percentage each year, and arithmetic, in which earnings increase or decrease by a fixed amount each year, are analyzed. Finally, an income model based on the binomial distribution is developed for evaluating projects which could have two income levels, each having an associated probability. Upper and lower confidence limits for the present and future worths of the project are calculated. Extensions are noted which will permit the inclusion of any of a number of levels of profit for each year of the project.     

Mucoadhesive nano-sized supramolecular assemblies for improved pre-corneal drug residence time

Abstract

Context: Mucoadhesive nanoparticles were compared with non-aggregated constituent polymers for effect on pre-corneal residence of dexamethasone phosphate (DP) or met-enkephalin (ME), administered by eye-drops to rabbits.

Objective: Deepening the knowledge of ophthalmic nanoparticulate systems in terms of ability to prolong pre-corneal residence.

Materials and methods: Medicated nanoparticles resulted from gelation of quaternary ammonium–chitosan conjugate or its thiolated derivative with hyaluronan in the presence of drug. Particles were analyzed by light scattering. Dialysis removed non-encapsulated drug, dynamic dialysis measured drug–polymer interactions, and lyophilization-stabilized product. Dispersions were regenerated from lyophilized products. Also solutions of non-thiolated or thiolated chitosan derivative were administered. Mean drug residence time (MRT) in tears was determined by collecting samples from lower marginal tear strip of albino rabbits using capillaries.

Results and discussion: Nanoparticle size of regenerated dispersions was 400–430?nm (DP-systems), 360–370?nm (ME-systems); the drug content was 2.5?mg/mL (DP) or 0.3?mg/mL (ME). The MRT for DP nanoparticles from non-thiolated derivative was higher than that for non-aggregated polymer, due to stronger concurrent interactions of positively charged nanoparticles with ocular surface and drug. Thiolated polymer nanoparticles and non-aggregated parent polymer, both interacting weakly with DP, showed similar MRT values. The MRT of ME could only be enhanced by protecting drug from enzymatic hydrolysis. This was done by nanoparticle systems, whereas non-aggregated polymers were ineffective.

Conclusion: Developing a nanoparticle system rather than a solution of mucoadhesive polymer, for prolonging pre-corneal residence, is convenient, provided nanoparticles interact strongly with both ocular surface and drug, or protect drug from metabolic degradation.     

Relationship between tensile strength and preparation conditions for nickel foam

Abstract

The relationship between preparation conditions and tensile strength has been investigated for a nickel foam produced by electrodeposition on an organic foam. After sintering in a NH₃ decomposition atmosphere at 980°C for 40 min, the results show that the tensile strength is hardly influenced by burning in air at 600°C for 4 min beforehand, or by lowering the sintering temperature to 850°C. During conductive treatment of the organic matrix it was found that coating with graphite base conductive colloid or chemically plating with Ni–P alloy (～5 wt-%P) brought the same tensile strength for the eventual product.     

NMR lineshapes in solid tritium and deuterium-tritium

We report on the NMR free induction decays (FID) from solid tritium (T₂), deuterium-tritium (D-T), and H₂, HD and D₂ containing 2% tritium. The FID in pure components is typically a beat decay for spin concentrations >30%, an exponential for spin concentrations <10%, and a Gaussian or Gaussian-exponential for spin concentrations in between. In mixtures of DT or HD, the deuteron FID is a Gaussian-exponential while the T or H FID is typically a beat decay or Gaussian depending on temperature. The linewidth is shown to consist mostly of intermolecular and intramolecular contributions, with a small component resulting from unpaired hydrogen atoms created by the tritium radioactivity.     

A combined FIC‐TDG finite element approach for the numerical solution of coupled advection–diffusion–reaction equations with application to a bioregulatory model for bone fracture healing

Numerical schemes for the approximative solution of advection–diffusion–reaction equations are often flawed because of spurious oscillations, caused by steep gradients or dominant advection or reaction. In addition, for strong coupled nonlinear processes, which may be described by a set of hyperbolic PDEs, established time stepping schemes lack either accuracy or stability to provide a reliable solution. In this contribution, an advanced numerical scheme for this class of problems is suggested by combining sophisticated stabilization techniques, namely the finite calculus (FIC‐FEM) scheme introduced by Oñate et al. with time‐discontinuous Galerkin (TDG) methods. Whereas the former one provides a stabilization technique for the numerical treatment of steep gradients for advection‐dominated problems, the latter ensures reliable solutions with regard to the temporal evolution. A brief theoretical outline on the superior behavior of both approaches will be presented and underlined with related computational tests. The performance of the suggested FIC‐TDG finite element approach will be discussed exemplarily on a bioregulatory model for bone fracture healing proposed by Geris et al., which consists of at least 12 coupled hyperbolic evolution equations. Copyright © 2012 John Wiley & Sons, Ltd.