Quantitative Selection Criteria Research Articles

The application of self-healing concept in Ni superalloys: Theoretical design and experimental validation

The self-healing mechanism has been newly applied in Ni superalloys to extend the creep lifetime during service. Quantitative selection criteria are proposed to screen the potential self-healing elements in Ni alloying system. Ti atoms and η-Ni3Ti precipitates are thus selected as the candidate healing atoms and the healing agent, respectively. The ideal composition interval for Ti to achieve the effective healing effects is computationally calculated as 0.076–0.1 mol fraction. On this basis, SHNi (self-healing Ni alloy) has been developed and compared with nSHNi (no self-healing Ni alloy). The creep lifetimes of SHNi alloys are observed 8–10 times higher than that of nSHNi alloys. Microstructure characterizations have shown that η-Ni3Ti healing agents in SHNi alloys can form site-specifically at the cavity sites during service. Meanwhile, the creep cavities in SHNi alloys present much smaller average sizes during creep, and the cavity growth rates are generally one magnitude lower compared to that of nSHNi alloys. The excellent creep properties of SHNi alloys can be well ascribed to their creep cavitation resistance brought by the self-healing behavior. The effectiveness of self-healing mechanism in improving the creep properties has proposed a new strategy in developing novel Ni superalloys.

Modernized Machine Learning Approach to Illuminate Enzyme Immobilization for Biocatalysis.

Biocatalysis is an established technology with significant application in the pharmaceutical industry. Immobilization of enzymes offers significant benefits for commercial and practical purposes to enhance the stability and recyclability of biocatalysts. Determination of the spatial and chemical distributions of immobilized enzymes on solid support materials is essential for an optimal catalytic performance. However, current analytical methodologies often fall short of rapidly identifying and characterizing immobilized enzyme systems. Herein, we present a new analytical methodology that combines non-negative matrix factorization (NMF)-an unsupervised machine learning tool-with Raman hyperspectral imaging to simultaneously resolve the spatial and spectral characteristics of all individual species involved in enzyme immobilization. Our novel approach facilitates the determination of the optimal NMF model using new data-driven, quantitative selection criteria that fully resolve all chemical species present, offering a robust methodology for analyzing immobilized enzymes. Specifically, we demonstrate the ability of NMF with Raman hyperspectral imaging to resolve the spatial and spectral profiles of an engineered pantothenate kinase immobilized on two different commercial microporous resins. Our results demonstrate that this approach can accurately identify and spatially resolve all species within this enzyme immobilization process. To the best of our knowledge, this is the first report of NMF within hyperspectral imaging for enzyme immobilization analysis, and as such, our methodology can now provide a new powerful tool to streamline biocatalytic process development within the pharmaceutical industry.

Corrosive Activity of Coal-Tar Wash Oils and Life of Equipment in Benzene Recovery

The corrosive activity of coal-tar wash oils is investigated. An electrochemical method is proposed for assessing the corrosive activity of the oil with respect to carbon steel. The main sources of corrosive impurities in the absorbers are identified. The contamination of the oil is assessed on the basis of its breakdown voltage. The results are in excellent agreement with analytical monitoring of the wash oils. Gravimetric data for the corrosive activity of the fluids in the existing system show that alloyed molybdenum steels are the most durable structural materials in the distillation department. In systems with a closed final-cooling cycle, the corrosive activity of the coal-tar oils may be reduced by scrubbing with water. Quantitative selection criteria are established for the water used.

Variation in protein composition among wheat (Triticum aestivum L.) cultivars to identify cultivars suitable as reference material for wheat gluten analysis

Gluten proteins of certain cereals (wheat, rye and barley) can trigger hypersensitivity reactions. In special dietary products for people intolerant to gluten, their amount must not exceed the regulatory threshold levels. The source of gluten can influence gluten quantitation due to variability in protein profile of grain cultivars and species. A proper reference material is crucial for accurate measurement of gluten and evaluating assay performance. It should be as representative of the commodity as possible. In this study, protein content and composition of a set of 23 common wheat cultivars grown around the world were determined. According to qualitative and quantitative selection criteria, cultivars that possessed a typical gluten composition were identified. Five cultivars were selected for subsequent experiments to confirm their suitability as a basis for reference material production.

Effect of Selected Airborne Contaminants on PEMFC Performance

Contaminants were selected from the Environmental Protection Agency lists. Six qualitative down selection criteria were used to reduce the list to the 21 1st tier contaminants. The effect of 1st tier contaminants, mostly organic with the exception of ozone, on PEMFC performance is reported. The behavior of these contaminants was classified into 5 different cases; no effect, recoverable effect, partly recoverable effect, irrecoverable effect and supra-recoverable effect. The steady state contamination and irrecoverable performance losses respectively varied from 0 to 90% and −2 to 80%. Contamination and recovery time scales significantly varied within a ∼0.01 to ∼28 h range. Acetaldehyde and propene were characterized by the new supra-recoverable effect. For trichlorofluoromethane, iso-propanol and propene, a decrease of the relative humidity led to a significant change in cell performance (steady states, time scales). This effect was ascribed to several causes including the scavenging effect of liquid water by contaminant dissolution and a non zero water reaction order. Two quantitative selection criteria based on observed fuel cell performance were used to reduce the 1st tier list to 7 2nd tier contaminants for more resource intensive tests. These 2nd tier contaminants are acetonitrile, acetylene, bromomethane, iso-propanol, methyl methacrylate, naphthalene and propene.

European Court of Justice: Quantitative Selection Criteria do not have to be Objectively Justified

European Court of Justice: Quantitative Selection Criteria do not have to be Objectively Justified

SELECCIÓN MULTICRITERIO DE CONTRATISTAS DE OBRAS. ENFOQUE BASADO EN REDES NEURONALES

This paper presents two cases of applying neural networks to extract knowledge for, subsequently, using it to support multicriteria contractor selection, in traditional design-bid-build projects with one-step selection processes. Different qualitative and quantitative selection criteria are taken into account, up to 22 and 9, respectively. The ? rst case includes a high number of input variables, making up a complex system related to complex and medium or large-sized projects. The second case is related to small projects in a medium-sized municipality. One advantage of these systems is that they can serve to ‘homogenize’ speci? c decision making in medium and large organizations. The paper also analyzes other pros of this approach, as well as the main problems.

Is the Gini Coefficient a Stable Measure of Galaxy Structure?

The Gini coefficient, a non-parametric measure of galaxy morphology, has recently taken up an important role in the automated identification of galaxy mergers. I present a critical assessment of its stability, based on a comparison of HST/ACS imaging data from the GOODS and UDF surveys. Below a certain signal-to-noise level, the Gini coefficient depends strongly on the signal-to-noise ratio, and thus becomes useless for distinguishing different galaxy morphologies. Moreover, at all signal-to-noise levels the Gini coefficient shows a strong dependence on the choice of aperture within which it is measured. Consequently, quantitative selection criteria involving the Gini coefficient, such as a selection of merger candidates, cannot always be straightforwardly applied to different datasets. I discuss whether these effects could have affected previous studies that were based on the Gini coefficient, and establish signal-to-noise limits above which measured Gini values can be considered reliable.

Survey for Transiting Extrasolar Planets in Stellar Systems. III. A Limit on the Fraction of Stars with Planets in the Open Cluster NGC 1245

We analyze a 19-night photometric search for transiting extrasolar planets in the open cluster NGC 1245. An automated transit search algorithm with quantitative selection criteria finds six transit candidates; none are bona fide planetary transits. We characterize the survey detection probability via Monte Carlo injection and recovery of realistic limb-darkened transits. We use this to derive upper limits on the fraction of cluster members with close-in Jupiter-radii, RJ, companions. We carefully analyze the random and systematic errors of the calculation. For similar photometric noise and weather properties as this survey, observing NGC 1245 twice as long results in a tighter constraint on Hot Jupiter, HJ, companions than observing an additional cluster of similar richness as NGC 1245 for the same length of time as this survey. This survey observed ~870 cluster members. If 1% of stars have 1.5 RJ HJ companions, we expect to detect one planet for every 5000 dwarf stars observed for a month. To reach a ~2% upper limit on the fraction of stars with 1.5 RJ HJ companions, we conclude a total sample size of ~7400 dwarf stars observed for at least a month will be needed. Results for 1.0 RJ companions, without substantial improvement in the photometric precision, will require a small factor larger sample size.

The time-profile of cell growth in fission yeast: model selection criteria favoring bilinear models over exponential ones

BackgroundThere is considerable controversy concerning the exact growth profile of size parameters during the cell cycle. Linear, exponential and bilinear models are commonly considered, and the same model may not apply for all species. Selection of the most adequate model to describe a given data-set requires the use of quantitative model selection criteria, such as the partial (sequential) F-test, the Akaike information criterion and the Schwarz Bayesian information criterion, which are suitable for comparing differently parameterized models in terms of the quality and robustness of the fit but have not yet been used in cell growth-profile studies.ResultsLength increase data from representative individual fission yeast (Schizosaccharomyces pombe) cells measured on time-lapse films have been reanalyzed using these model selection criteria. To fit the data, an extended version of a recently introduced linearized biexponential (LinBiExp) model was developed, which makes possible a smooth, continuously differentiable transition between two linear segments and, hence, allows fully parametrized bilinear fittings. Despite relatively small differences, essentially all the quantitative selection criteria considered here indicated that the bilinear model was somewhat more adequate than the exponential model for fitting these fission yeast data.ConclusionA general quantitative framework was introduced to judge the adequacy of bilinear versus exponential models in the description of growth time-profiles. For single cell growth, because of the relatively limited data-range, the statistical evidence is not strong enough to favor one model clearly over the other and to settle the bilinear versus exponential dispute. Nevertheless, for the present individual cell growth data for fission yeast, the bilinear model seems more adequate according to all metrics, especially in the case of wee1Δ cells.

Iatrogenic Femoral Pseudoaneurysms That Are Unresponsive to Percutaneous Thrombin Injection: Potential Causes

We sought to determine whether any quantitative selection criteria can be established to predict which pseudoaneurysms of the common femoral artery will fail to respond to thrombin. SUBJECTS AND METHODS. Under sonographic guidance, we injected thrombin into 54 consecutive iatrogenic pseudoaneurysms of the common femoral artery. We statistically compared the volume, maximum dimension, and neck diameter of the pseudoaneurysms and thrombin doses injected into the successfully treated (persistent thrombosis on a follow-up duplex sonogram obtained 7-10 days after thrombin injection) and unresponsive (sonographically documented recurrence within 24 hr) pseudoaneuryms to determine whether any of these factors could help to predict a failure to respond to thrombin. For all patients in whom treatment failed, findings at surgical repair were noted and sonograms were reviewed to confirm the dimensions and appearance of the pseudoaneurysm and the absence of an associated arteriovenous fistula. Complete and persistent thrombosis was achieved in 49 (91%) of the 54 common femoral artery pseudoaneurysms. In comparing the 49 successfully treated patients and the five patients in whom treatment failed, we identified no significant differences in the volume, maximum dimension, or neck diameter of the pseudoaneurysm (two-sample t test) or in the thrombin dose (Wilcoxon's rank sum test). In all five patients with failed treatment, an arteriotomy site laceration measuring at least 8.0 mm (n = 4) or infection (n = 1) was identified at surgical repair, none of which were identifiable even in retrospect on duplex and color Doppler sonography. Failure of an iatrogenic pseudoaneurysm of the common femoral artery to respond to thrombin may indicate an occult vascular injury. In these patients, surgical repair, rather than reinjection of thrombin, should be considered.

The stellar content of the Hamburg/ESO survey

We describe automatic procedures for the selection of DA white dwarfs in the Hamburg/ESO objective-prism survey (HES). For this purpose, and the selection of other stellar objects (e.g., metal-poor stars and carbon stars), a flexible, robust algorithm for detection of stellar absorption and emission lines in the digital spectra of the HES was developed. Broad band (, ) and intermediate band (Strömgren c1) colours can be derived directly from HES spectra, with precisions of mag; mag; mag. We describe simulation techniques that allow one to convert model or slit spectra to HES spectra. These simulated objective-prism spectra are used to determine quantitative selection criteria, and for the study of selection functions. We present an atlas of simulated HES spectra of DA and DB white dwarfs. Our current selection algorithm is tuned to yield maximum efficiency of the candidate sample (minimum contamination with non-DAs). DA candidates are selected in the versus and c1 versus parameter spaces. The contamination of the resulting sample with hot subdwarfs is expected to be as low as ∼8% , while there is essentially no contamination with main sequence or horizontal branch stars. We estimate that with the present set of criteria, ∼80% of DAs present in the HES database are recovered. A yet higher degree of internal completeness could be reached at the expense of higher contamination. However, the external completeness is limited by additional losses caused by proper motion effects and the epoch differences between direct and spectral plates used in the HES.

064 Sugars in Tropical-type Sweetpotato

Tropical-type is a general description for sweetpotato cultivars with intermediate sweetness that have light-fleshed roots. This type is commonly grown and consumed across the Caribbean Basin. Systematic efforts for the genetic improvement of the tropical-type sweetpotato have been limited. Cultivars available for being grown in Puerto Rico lack either the sweetness or attractiveness demanded by producers and consumers. Defining optimum sweetness in this type is important because this characteristic is totally dependent on the root's sugar content and cannot be modified as in processed products. The objective was to obtain data on sugar content for the development of quantitative selection criteria for sweetness. Raw, boiled and baked roots were evaluated for glucose, sucrose, fructose, and maltose. `Mina' and `Miguela', tropical-type cultivars widely accepted for sweetness and table quality but poor yielders were used. `Viola', a substaple type, was the check. Sugars were detected by HPLC. Sugar-Pak (Waters) and LC-NH2 (Phenomenex) columns and a refractive index detector were used for the analyses. Across cultivars and type, sucrose (4.0% to 6.5%) was more concentrated than glucose (0.4% to 0.8%) and fructose (0.3% to 0.4%). Concentration of sucrose in the tropical type (7.7%) was higher than in the substaple type check (4.4%). Boiling or baking did not markedly change the concentration of the above sugars. Maltose was not detected in raw samples; however, both boiling and baking increased maltose concentration from 9.0% to 15.4%. In the development of a practical quantitative selection criteria for sweetness, both sucrose and maltose must be considered.

Linear assessment of the thoroughbred horse: an approach to conformation evaluation.

A linear assessment trait evaluation system is proposed to allow quantitative description of the static conformation of the horse. Measurements were made on 27 selected traits. The system was tested initially for repeatability of measurements on 4 horses. Twenty-one of the selected traits were satisfactory and 6 proved unsatisfactory in terms of reproducibility. A population of 101, superior 2- and 3-year-old Thoroughbreds and 19 premium Thoroughbred stallions were similarly assessed. More than 65% of the traits exhibited large (CV > 10%) phenotypic variation within the sampled population. It is proposed that such a system of static conformation assessment, in conjunction with a similar system for dynamic linear assessment, would provide useful quantitative selection criteria in the description and breeding of horses.

Stomatal responses to light and humidity in sugarcane: prediction of daily time courses and identification of potential selection criteria

AbstractStomatal sensitivities to light and VPD have potential as quantitative selection criteria in programs designed to enhance water‐use efficiency of sugarcane and other crops. These responses were characterized using gas exchange techniques and then simulated by a mathematical relationship describing conductance as a function of photon fluence rates and VPD values. The same form of relationship simulated stomatal responses of well‐watered greenhouse‐ and field‐grown plants. A comparison between simulated and measured conductance values showed a close correlation, indicating that light and VPD responses of stomata are dominant input signals modulating stomatal conductance in sugarcane. Observed conductance of Hawaiian sugarcane in a commerical production area appeared larger than required to support prevailing rates of carbon assimilation, since predicted intercellular CO2was greater than required to saturate its C4photosynthesis. Manipulation of the relationship describing stomatal conductance allowed us to simulate the responses of plants with hypothetically altered stomatal sensitivities to VPD or to light, using micrometeorological data collected in the field. Further simulation indicated that selection for clones with altered stomatal sensitivity to either light or VPD could improve the water‐use efficiency of sugarcane without inhibiting current high levels of productivity.

Peculiarities of binary galaxies

A recent analysis of a sample of close binary galaxies1 by White and Valdes2 has revealed some peculiar features: in particular, they tend to be brighter than field galaxies. Binary galaxies are important because the relative simplicity of the two-body problem in dynamics should make it possible to obtain good estimates of the masses of paired galaxies. This would help in determining whether there are massive haloes of dark, unseen matter, and in the problem area of galaxy formation. Much effort has therefore been expended (ref. 3 and refs therein), but conclusions about the existence of massive haloes and about the mass-to-light ratios have varied. Because we do not have complete information, various statistical assumptions must be made in these analyses. Detailed arguments2 suggest that one of these assumptions has been in error in previous work. We present a test which supports this claim. (The sample used here and in ref. 2 seems to be the only set of paired galaxies with quantitative selection criteria and velocity information for an unbiased subsample.) Furthermore, it was shown2 that binary galaxies are drawn from a luminosity function which has a characteristic luminosity brighter than that for field galaxies by almost one whole magnitude. We discuss one of the possible explanations and some suggestive evidence.