On a Statistical Fault Diagnosis Approach Enabling Fast Yield Ramp-Up

The ability to achieve and maintain high yield levels is directly dependent on the capability to detect and analyze repetitive failure mechanisms. In this paper, an advanced statistical diagnosis method, using the final wafer test results, is presented. The new method builds on an existing full diagnosis method, and studies the adaptations needed to turn it into an effective and efficient on-line statistical diagnosis approach. The output of the new approach is a (limited) list of suspect locations, which acts as input for further statistical and physical analysis. The experiments performed show the efficiency as well as the limitations of the proposed approach.     

An efficient and innovative method to preserve the harvested plums during storage

This research was undertaken to establish the preservative role of lactic acid (LA) and salicylic acid (SA) included in a gelatin–glycerol film over the harvested plums. The results showed that highest catalase activity was achieved for the plums modified with LA 0.2% wt and with SA 0.00375 M, after 12 days of storage. The most reduced variation of the physical, chemical, and enzymatic parameters was noticed in the plums coated with LA 0.2% wt. Statistical processing showed that the variation of all physical–chemical parameters, excepting catalase is significant. Variation of catalase is significant only in the case of the plums modified with LA 3% wt and of reference plums. Thus, the coating of the harvested plums with a low amount of LA (≤0.2% wt) can be considered as preservation method during storage for 12 days.

Practical applications

Lactic acid (LA) and salicylic acid (SA) were coated on the harvested plums and their role as preservative during the fruit storage was established. The results showed that coating the harvested plums with a gelatin–glycerol film modified with LA at low concentration (≤0.2% wt) is an efficient method for preservation at room temperature for 12 days, taking in consideration that the commercial shelf life of harvested plums is 2–6 weeks, at 0 °C.     

Antimicrobial activity of the surface coatings on TiAlZr implant biomaterial

This study is devoted to antimicrobial activity of new surface coatings on TiAlZr. Ti alloys such as TiAlZr are used as implant biomaterials, but, despite the good behavior of such alloys in simulated conditions, bacterial infections appear after the introduction of an implant into the body. The infections are typically caused by the adherence and colonization of bacteria on the surfaces of the implants. The study presents preparation and surface morphology characterization of coatings obtained via anodizing, as well as biomimetic coatings with hydroxyapatite and silver ions with and without antibiotic. The percentage inhibition of Escherichia coli bacteria growth was evaluated for each of the studied coating, and a Trojan-horse model of silver nanoparticles (nAg) antibacterial activity at interface was proposed. Such coatings could be more important taking into account that antibacterial treatments with antibiotics are becoming less effective due to their intensive use.     

A methodology of computation,design and optimization of solar Stirling power plant using hydrogen/oxygen fuel cells

The objective of this paper is to develop a methodology to determine how many houses could be fueled from the solar energy captured by a number of solar Stirling modules (with a fixed dish area per module) and also to determine the minimum necessary area of the fuel cell to ensure the amount of power needed to meet daily energy use requirements. The detailed method includes the effect of the fuel cell efficiency function on the power consumption of the user. Experimental data from our laboratory are used to determine the fuel cell efficiency as a function of the electric current density for a specific power demand. As an illustrative example, the analysis is applied to a residential area having a specific electrical demand. Using the developed method, the number of houses that could be fueled directly by the stored hydrogen is determined, and also the minim fuel cell area required.     

Environment driven cereulide production by emetic strains of Bacillus cereus

The impacts of growth media and temperature on production of cereulide, the emetic toxin of Bacillus cereus, were measured for seven well characterised strains selected for diversity of biochemical and genetic properties and sources of origin. All strains carried cereulide synthase gene, ces, on a megaplasmid of ca. 200 kb and all grew up to 48-50 degrees C, but produced cereulide only up to 39 degrees C. On tryptic soy agar five strains, originating from foods, food poisonings and environment, produced highest amounts of cereulide at 23 to 28 degrees C, whereas two strains, from human faeces, produced cereulide similarly from 23 to 39 degrees C, with no clear temperature trend. These two strains differed from the others also by producing more cereulide on tryptic soy agar if supplemented with 5 vol.% of blood, whereas the other five strains produced similarly, independent on the presence of blood. On oatmeal agar only one strain produced major amounts of cereulide. On skim milk agar, raw milk agar, and MacConkey agar most strains grew well but produced only low amounts of cereulide. Three media components, the ratio [K(+)]:[Na(+)], contents of glycine and [Na(+)], appeared of significance for predicting cereulide production. Increase of [K(+)]:[Na(+)] (focal variable) predicted (P<0.001) high cereulide provided that the contents of glycine and [Na(+)] (additional variables) were kept constant. The results show that growth medium and temperature up and downregulate cereulide production by emetic B. cereus in a complex manner. The relevance of the findings to production of cereulide in the gut and to the safety of amino acids as additives in foods containing live toxinogenic organisms is discussed.     

Case Study of Steady Oxygen Concentration Gradients in a Groundwater Plume from a Highway Infiltration Basin

We measure and model the steady transport of specific conductivity and dissolved oxygen through a groundwater plume from a highway infiltration basin in southeastern Massachusetts. Specific conductivity is treated as a conservative surrogate for runoff contamination, and the data calibrate a 0.27-m vertical dispersivity α of the aquifer and the bottom streamline elevation of the plume, which falls to an 8-m depth below the water table. The dissolved oxygen degrades as a first order reactant in the plume to levels below 1 mg/L, with a decay constant λ of 0.12?day?1. The latter may be attributed in part to the historical use of an alternative de-icing agent calcium magnesium acetate on the highway, since acetate is a readily biodegradable substrate for microorganisms. The calibrated kinetics suggest that plume microbes and geochemistry degrade oxygen over two orders of magnitude faster than their ambient groundwater counterparts, which impose a linear decrease of dissolved oxygen concentration below the plume. Simulations suggest that the anoxic groundwater plume extends 1,600 m downgradient of the infiltration basin, a distance that will shorten by an order of magnitude if salt is used exclusively to de-ice the highway.     

Antibacterial activity of silver-modified natural clinoptilolite

The aim of the present work was to estimate the bactericidal activity and efficacy of silver pre-treated clinoptilolite-rich tuff from Marsid (Romania) in solid media (agar plates) against Gram-negative Escherichia coli ATCC 25922 and Gram-positive Staphylococcus aureus ATCC 25923. Two samples of natural clinoptilolite-rich tuff was first pre-treated with oxalic acid and sodium hydroxide solutions, respectively. The sample treated with oxalic acid was then exchanged with sodium chloride solution to obtain sodium form. Finally, both samples were exchanged with silver nitrate solution at room temperature for 24 h to obtain silver forms (P1-Ag⁺ and P2-Ag⁺) of clinoptilolite. The structure, morphology, and elemental composition of the pre-treated clinoptilolite samples were characterized by XRD, infrared (ATR-IR), SEM, and EDX analysis. The antibacterial activity was investigated by exposing E. coli and S. aureus in nutritive agar to the silver-clinoptilolite samples. Microorganisms were completely inhibited at 2 mg Ag⁺-clinoptilolite/mL nutritiv medium after 24 h of incubation at 37 °C. The silver-clinoptilolite sample derived from natural clinoptilolite pre-treated with oxalic acid (P1-Ag⁺) exhibit a stronger antibacterial effect in the presence of E. coli and the sample derived from natural clinoptilolite pre-treated with sodium hydroxide (P2-Ag⁺) in the presence of S. aureus.     

Structured light self-calibration with vanishing points

This paper introduces the vanishing points to self-calibrate a structured light system. The vanishing points permit to automatically remove the projector’s keystone effect and then to self-calibrate the projector–camera system. The calibration object is a simple planar surface such as a white paper. Complex patterns and 3D calibrated objects are not required any more. The technique is compared to classic calibration and validated with experimental results.     

A uniform object-oriented solution to the eigenvalue problem for real symmetric and Hermitian matrices

We present a system of classes, SHMatrix, to deal in a unified way with the computation of eigenvalues and eigenvectors in real symmetric and Hermitian matrices. Thus, two descendant classes, one for the real symmetric and other for the Hermitian cases, override the abstract methods defined in a base class. The use of the inheritance relationship and polymorphism allows handling objects of any descendant class using a single reference of the base class. The system of classes is intended to be the core element of more sophisticated methods to deal with large eigenvalue problems, as those arising in the variational treatment of realistic quantum mechanical problems. The present system of classes allows computing a subset of all the possible eigenvalues and, optionally, the corresponding eigenvectors. Comparison with well established solutions for analogous eigenvalue problems, as those included in LAPACK, shows that the present solution is competitive against them.

Program summary

Program title: SHMatrixCatalogue identifier: AEHZ_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHZ_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 2616No. of bytes in distributed program, including test data, etc.: 127 312Distribution format: tar.gzProgramming language: Standard ANSI C++.Computer: PCs and workstations.Operating system: Linux, Windows.Classification: 4.8.Nature of problem: The treatment of problems involving eigensystems is a central topic in the quantum mechanical field. Here, the use of the variational approach leads to the computation of eigenvalues and eigenvectors of real symmetric and Hermitian Hamiltonian matrices. Realistic models with several degrees of freedom leads to large (sometimes very large) matrices. Different techniques, such as divide and conquer, can be used to factorize the matrices in order to apply a parallel computing approach. However, it is still interesting to have a core procedure able to tackle the computation of eigenvalues and eigenvectors once the matrix has been factorized to pieces of enough small size. Several available software packages, such as LAPACK, tackled this problem under the traditional imperative programming paradigm. In order to ease the modelling of complex quantum mechanical models it could be interesting to apply an object-oriented approach to the treatment of the eigenproblem. This approach offers the advantage of a single, uniform treatment for the real symmetric and Hermitian cases.Solution method: To reach the above goals, we have developed a system of classes: SHMatrix. SHMatrix is composed by an abstract base class and two descendant classes, one for real symmetric matrices and the other for the Hermitian case. The object-oriented characteristics of inheritance and polymorphism allows handling both cases using a single reference of the base class. The basic computing strategy applied in SHMatrix allows computing subsets of eigenvalues and (optionally) eigenvectors. The tests performed show that SHMatrix is competitive, and more efficient for large matrices, than the equivalent routines of the LAPACK package.Running time: The examples included in the distribution take only a couple of seconds to run.     

Highly sensitive label-free immunosensor for ochratoxin A based on functionalized magnetic nanoparticles and EIS/SPR detection

A label-free immunosensor for the detection of ochratoxin A (OTA) based on use of magnetic nanoparticles (MNPs) was developed. A gold electrode was modified using bovine serum albumin conjugate with a glutaraldehyde-thiolamine linker, creating a layer that prevents non-specific binding of OTA on gold. The OTA antibodies were attached to MNPs using the carbodiimide chemistry and afterwards were immobilized on the modified gold electrode using a strong magnetic field. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and surface plasmon resonance (SPR) were used to characterize each step in immunosensor development. The impedance variation due to the specific antibody-OTA interaction was correlated with the OTA concentration in the samples. The increase in electron-transfer resistance values was proportional to the concentration of OTA on a linear range between 0.01 and 5 ng/mL, with a detection limit of 0.01 ng/mL. SPR measurements showed a larger response range (1-50 ng/mL) with a detection limit of 0.94 ng/mL. Analytical results were in accordance with standard ELISA test kit.