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71.
Alison Kretser Delia Murphy Johanna Dwyer 《Critical reviews in food science and nutrition》2017,57(1):163-180
Scientific integrity is at the forefront of the scientific research enterprise. This paper provides an overview of key existing efforts on scientific integrity by federal agencies, foundations, nonprofit organizations, professional societies, and academia from 1989 to April 2016. It serves as a resource for the scientific community on scientific integrity work and helps to identify areas in which more action is needed. Overall, there is tremendous activity in this area and there are clear linkages among the efforts of the five sectors. All the same, scientific integrity needs to remain visible in the scientific community and evolve along with new research paradigms. High priority in instilling these values falls upon all stakeholders. 相似文献
72.
Luis Carlos Méndez‐González Luis Alberto Rodríguez‐Picón Delia Julieta Valles‐Rosales Roberto Romero‐López Abel Eduardo Quezada‐Carreón 《Quality and Reliability Engineering International》2017,33(8):2521-2530
Today, in reliability analysis, the most used distribution to describe the behavior of electronic products under voltage profiles is the Weibull distribution. Nevertheless, the Weibull distribution does not provide a good fit to lifetime datasets that exhibit bathtub‐shaped or upside‐down bathtub–shaped (unimodal) failure rates, which are often encountered in the reliability analysis of electronic devices. In this paper, a reliability model based on the beta‐Weibull distribution and the inverse power law is proposed. This new model provides a better approach to model the performance and fit of the lifetimes of electronic devices. To estimate the parameters of the proposed model, a Bayesian analysis is used. A case study based on the lifetime of a surface mounted electrolytic capacitor is presented, the results showed that the estimation of the proposed model differs from the inverse power law–Weibull and that it affects directly the mean time to failure, the failure rate, the behavior, and the performance of the capacitor under analysis. 相似文献
73.
A multiple system governed by a quasi-birth-and-death process 总被引:2,自引:2,他引:2
The system we consider comprises n units, of which one has to operate for the system to work. The other units are in repair, in cold standby, or waiting for repair. Only the working unit can fail. The operational and repair times follow phase-type distributions. Upon failure, it is replaced by a standby unit and goes to the repair facility. There is only one repairman. When one unit operates the system is up and when all the units are in repair or waiting for repair, the system is down. This system is governed by a finite quasi-birth-and-death process. The stationary probability vector and useful performance measures in reliability, such as the availability and the rate of occurrence of failures are explicitly calculated. This model extends other previously considered in the literature. The case with an infinite number of units in cold standby is also studied. Computational implementation of the results is performed via a numerical example, and the different systems considered are compared from the reliability measures determined. 相似文献
74.
Lobna Kriaa Aimen Bouchhima Marius Gligor Anne-Marie Fouillart Fréderic Pétrot Ahmed-Amine Jerraya 《International journal of parallel programming》2008,36(1):68-92
For the design of classic computers the parallel programming concept is used to abstract HW/SW interfaces during high level
specification of application software. The software is then adapted to existing multiprocessor platforms using a low level
software layer that implements the programming model. Unlike classic computers, the design of heterogeneous MPSoC includes
also building the processors and other kind of hardware components required to execute the software. In this case, the programming
model hides both hardware and software refinements. This paper deals with parallel programming models to abstract both hardware
and software interfaces in the case of heterogeneous MPSoC design. Different abstraction levels will be needed. For the long
term, the use of higher level programming models will open new vistas for optimization and architecture exploration like CPU/RTOS
tradeoffs. 相似文献
75.
Luciano Atzori Maria Giorgia Cutrufello Daniela Meloni Barbara Onida Delia Gazzoli Andrea Ardu Roberto Monaci Maria Franca Sini Elisabetta Rombi 《Frontiers of Chemical Science and Engineering》2021,15(2):251-268
Nanosized NiO,CeO2 and NiO-CeO2 mixed oxides with different Ni/Ce molar ratios were prepared by the soft template method.All the samples were characterized by different techniques as to their chemical composition,structure,morphology and texture.On the catalysts submitted to the same reduction pretreatment adopted for the activity tests the surface basic properties and specific metal surface area were also determined.NiO and CeO2 nanocrystals of about 4 nm in size were obtained,regardless of the Ni/Ce molar ratio.The Raman and X-ray photoelectron spectroscopy results proved the formation of defective sites at the NiO-CeO2 interface,where Ni species are in strong interaction with the support.The microcalorimetric and Fourier transform infrared analyses of the reduced samples highlighted that,unlike metallic nickel,CeO2 is able to effectively adsorb CO2,forming carbonates and hydrogen carbonates.After reduction in H2 at 400°C for 1 h,the catalytic performance was studied in the CO and CO2 co-methanation reaction.Catalytic tests were performed at atmospheric pressure and 300°C,using CO/CO2/H2 molar compositions of 1/1/7 or 1/1/5,and space velocities equal to 72000 or 450000 cm3?h-1?gcat-1.Whereas CO was almost completely hydrogenated in any investigated experimental conditions,CO2 conversion was strongly affected by both the CO/CO2/H2 ratio and the space velocity.The faster and definitely preferred CO hydrogenation was explained in the light of the different mechanisms of CO and CO2 methanation.On a selected sample,the influence of the reaction temperature and of a higher number of space velocity values,as well as the stability,were also studied.Provided that the Ni content is optimized,the NiCe system investigated was very promising,being highly active for the COx co-methanation reaction in a wide range of operating conditions and stable(up to 50 h)also when submitted to thermal stress. 相似文献
76.
A simple and general definition of denial-of-service in operating systems is presented. It is argued that no current protection mechanism nor model resolves this problem in any demonstrable way. The notion of interuser dependency is introduced and identified as the common cause for all problem instances. Decomposition of operating systems into hierarchies of services is assumed for the discovery of denial-of-service instances. 相似文献
77.
Giovanni Ferraris Sergio De Rossi Delia Gazzoli Ida Pettiti Mario Valigi Giuliana Magnacca Claudio Morterra 《Applied Catalysis A: General》2003,240(1-2):119-128
The adsorption of CO at 77 K on zirconia-supported tungsten oxide (ZW) samples prepared by equilibrium adsorption or by impregnation and with tungsten content up to 12.4 W atoms nm−2 was studied with the aim of determining the coverage of ZrO2 surface by the supported tungsten oxospecies. As an essential background for quantitative volumetric measurements, ZW samples were investigated by FT-IR spectroscopy to identify the surface sites responsible for the CO adsorption. FT-IR showed that CO adsorbed selectively and irreversibly on Zrcus4+ centers of the support surface, but not on Wcus6+ sites. By volumetric determinations, the coverage of the zirconia surface by tungsten oxospecies was about 50% at maximum, irrespective of the preparation procedure and of the support crystallographic modification (monoclinic or tetragonal). Zirconia coverage remained significantly unchanged after leaching with a NH3 solution that removed tungsten oxospecies not directly interacting with the zirconia surface. This finding indicates that ZrO2 support coverage depends mainly on the tungsten species strongly anchored to the zirconia surface. 相似文献
78.
Wittig de Penna E Avendaño P Soto D Bunger A 《Archivos latinoamericanos de nutrición》2003,53(1):74-83
This study presents the development of individual cakes enriched with dietary fiber (lupin and oat fiber), vitamins and minerals; as recent research has shown that the average daily dietary fibre intake of the elderly population in Chile is only 12 g. Each cake contains 4.8 g of dietary fibre and a 30% of the RDA of vitamins A, B1, B2, B6, B12, E, nicotinamide and folic acid, 40% of the RDA of vitamin D3, 15% of the RDA of calcium, 12% of the RDA of magnesium and 3% the RDA of zinc. Polydextrose and sorbitol were added to improve flavor and texture. Response Surface Methodology (RSM) was used for optimization, based on a two-variable composite design. Thirteen experimental runs were carried out, with polydextrose (1 to 40% based on flour content) and sorbitol (1 to 30% based on flour content) as independent variables. The response variable was sensory quality obtained by the Karlsruhe test. Sensory attributes of texture and overall quality showed a good fitting with high determination coefficients and were used for optimization. The optimized cake contained 11.5% polydextrose and 4.4% sorbitol (both based on flour content). Quality of the optimized product was controlled by means of physical, chemical, microbiological and sensory analyses. Overall sensory quality was 8.18 ("very good") and good quality and nutritive value were achieved. In an acceptance test carried out with 150 adults, 100% acceptability was obtained in the hedonic scale categories "like it" and "like it very much". A shelf life study performed with cakes packaged in polypropylene bags of 30 microns thickness indicated a shelf life of 13 days stored at room conditions (25 degrees C and 55-60% R.H.). 相似文献
79.
Roberto Sanz Alberto Martínez Delia Miguel JuliaM. lvarez‐Gutirrez Flix Rodríguez 《Advanced Synthesis \u0026amp; Catalysis》2006,348(14):1841-1845
Simple Brønsted acids such as p‐toluenesulfonic acid monohydrate (PTS) or polymer‐bound p‐toluenesulfonic acid efficiently catalyze the direct nucleophilic substitution of the hydroxy group of allylic and benzylic alcohols with a large variety of carbon‐ and heteroatom‐centered nucleophiles. Reaction conditions are mild, the process is conducted under an atmosphere of air without the need for dried solvents, and water is the only side product of the reaction. 相似文献
80.
Hadi AlQahtani Mark Sugden Delia Puzzovio Lee Hague Nic Mullin Tim Richardson Martin GrellAuthor vitae 《Sensors and actuators. B, Chemical》2011,160(1):399
We deposit dense, ordered, thin films of Au–dodecanethiol core/shell nanoparticles by the Langmuir–Schäfer (LS) printing method, and find that their resistance at ambient temperature responds selectively and sensitively to alkane odours. Response is a rapid resistance increase due to swelling, and is strongest for alkane odours where the alkane chain is similar in length to the dodecane shell. For decane odours, we find a response to concentrations as low as 15 ppm, about 600 times below the lower explosive limit. Response is weaker, but still significant, to aromatic odours (e.g. Toluene, Xylene), while potential interferants such as polar and/or hydrogen-bonding odours (e.g. alcohols, ketones, water vapour) are somewhat rejected. Resistance is weakly dependent on temperature, and recovers rapidly and completely to its original value within the error margin of measurement. 相似文献