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1.
Single-wall carbon nanotubes (SWNTs) prepared by the arc discharge method were oxidized using nitric acid. The samples were analyzed by using Raman scattering and Fourier transformed infrared spectroscopy (FTIR). The FTIR results indicate the presence of -COOH acid groups in the treated samples. The up shifts observed in the radial breathing mode frequencies suggest that SWNTs behave as donors after the acid treatment, with charge transfer occurring from the nanotubes to the -COOH groups. Ab initio calculations of SWNTs interacting with -COOH acid groups support the charge transfer process from the nanotubes to the carboxyl groups. 相似文献
2.
Dobson CA Sisias G Phillips R Fagan MJ Langton CM 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2006,220(3):481-484
Stereolithography (STL) models of complex cancellous bone structures have been produced from three-dimensional micro-computed tomography data sets of human cancellous bone histological samples from four skeletal sites. The STL models have been mechanically tested and the derived stiffness compared with that predicted by finite element analysis. The results show a strong correlation (R2 = 0.941) between the predicted and calculated stiffnesses of the structures and show promise for the use of STL as an additional technique to complement the use of finite element models, for the assessment of the mechanical properties of complex cancellous bone structures. 相似文献
3.
The current aqueous cleaning step in the surface preparation of aluminum nitride (AlN) prior to metallization causes performance and reliability issues for the substrates used for microelectronic packaging due to surface reactions. These issues limit the use of AlN and its replacing of BeO, an environmentally hazardous material currently used. The aim of this investigation was to determine the effects of different solutions on the surface of AlN substrates under varying conditions at times up to 2419.2 ks (28 days). Concentration of the solutions, temperature, and immersion time were varied for the AlN samples in the solutions. Both elevated temperatures (50°C and 90°C) and low temperatures (5°C) were investigated.
Four general types of behavior were observed: minor changes in average surface roughness and microstructure, linear change in average surface roughness and pitted grains, nonlinear change in average surface roughness and product formation on AlN surface, and miscellaneous change in average surface roughness with surface product formation.
The surface roughening kinetics were very complex due to changes in both the reaction product morphology and reaction mechanism with temperature, solvent, and pH for a specific solvent. Minor changes in average surface roughness and microstructure were observed for HCl pH = 5, H2 SO4 pH = 5, NaOH pH = 8, NaOH pH = 10, NaOH pH = 12, deionized water and Alfred tap water at 5°C, HCl pH = 3 and oleic acid at 50°C and citric acid and oleic acid at 90°C. Linear changes in average surface roughness and pitted grains were observed for HCl pH = 2 and H2SO4 pH = 3 at 50°C and HCl pH = 2, H2SO4 pH = 3, and deionized water at 90°C. Non-linear change in average surface roughness and product formation on AlN surface was observed for HCl pH = 5, NaOH pH = 8 and Alfred tap water at 50°C and HCl pH = 5 and H2SO4 pH = 2 at 90°C. Miscellaneous changes in average surface roughness with surface product formation were observed for H2SO4 pH = 2, H2SO4 pH = 5, NaOH pH = 10, NaOH pH = 12, citric acid, Micro-90 and deionized water at 50°C and HCl pH = 3, H2SO4 pH = 5, NaOH pH = 8, NaOH pH = 10, NaOH pH = 12, Micro-90 and Alfred tap water at 90°C. 相似文献
Four general types of behavior were observed: minor changes in average surface roughness and microstructure, linear change in average surface roughness and pitted grains, nonlinear change in average surface roughness and product formation on AlN surface, and miscellaneous change in average surface roughness with surface product formation.
The surface roughening kinetics were very complex due to changes in both the reaction product morphology and reaction mechanism with temperature, solvent, and pH for a specific solvent. Minor changes in average surface roughness and microstructure were observed for HCl pH = 5, H2 SO4 pH = 5, NaOH pH = 8, NaOH pH = 10, NaOH pH = 12, deionized water and Alfred tap water at 5°C, HCl pH = 3 and oleic acid at 50°C and citric acid and oleic acid at 90°C. Linear changes in average surface roughness and pitted grains were observed for HCl pH = 2 and H2SO4 pH = 3 at 50°C and HCl pH = 2, H2SO4 pH = 3, and deionized water at 90°C. Non-linear change in average surface roughness and product formation on AlN surface was observed for HCl pH = 5, NaOH pH = 8 and Alfred tap water at 50°C and HCl pH = 5 and H2SO4 pH = 2 at 90°C. Miscellaneous changes in average surface roughness with surface product formation were observed for H2SO4 pH = 2, H2SO4 pH = 5, NaOH pH = 10, NaOH pH = 12, citric acid, Micro-90 and deionized water at 50°C and HCl pH = 3, H2SO4 pH = 5, NaOH pH = 8, NaOH pH = 10, NaOH pH = 12, Micro-90 and Alfred tap water at 90°C. 相似文献
4.
The development of poly(vinyl chloride) extrusions for a 14,000‐ton self‐supporting structure for the detection of neutrinos 下载免费PDF全文
James J. Grudzinski Richard L. Talaga Anna Pla‐Dalmau James E. Fagan Charles Grozis Karen Kephart Richard Fischer 《乙烯基与添加剂工艺杂志》2016,22(3):368-376
The NOvA Neutrino Experiment has built a one‐of‐a‐kind self‐supporting plastic structure, potentially the largest ever built. The poly(vinyl chloride) (PVC) structure serves as a neutrino detector and is composed of 28 individual blocks that measure 15.5 m (51 feet) high by 15.5 m (51 feet) wide by 2.1 m (7 feet) deep. The primary parts in the detector construction are 15.5‐m (51‐foot), 16‐cell PVC extrusions. These extrusions form the basis of the detector modules, which are laminated together in a crossed pattern to form the individual blocks and then filled with (mineral oil)–based liquid scintillator. The self‐supporting nature of the detector places important structural requirements on both the PVC formulation and the extrusions. Block assembly requirements impose narrow geometric tolerances. Because of the method of detecting neutrinos, the extrusions must possess exceptionally high reflectivity over a particular wavelength range. This requirement places additional restrictions on the components of the PVC formulation. Altogether, the PVC extrusions have to maintain important reflectivity characteristics, provide structural support to the detector, and meet relatively tight geometric requirements for assembly. In order to meet these constraints, a custom PVC formulation had to be created and extruded. We describe the purpose and requirements of the NOvA detector leading to the production of our unique PVC extrusion, summarize the research and development process, and discuss the lessons learned. J. VINYL ADDIT. TECHNOL., 22:368–376, 2016. © 2014 Society of Plastics Engineers 相似文献
5.
6.
Watson PJ O'Higgins P Fagan MJ Dobson CA 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2011,225(1):48-57
Three-dimensional reconstructions of bone geometry from microCT (computed tomography) data are frequently used in biomechanical and finite element analyses. Digitization of bone models is usually a simple process for specimens with a complete geometry, but in instances of damage or disarticulation it can be very challenging. Subsequent to digitization, further imaging techniques are often required to estimate the geometry of missing bone or connecting cartilage. This paper presents an innovative approach to the reconstruction of incomplete scan data, to reproduce proper anatomical arrangements of bones, including absent connecting cartilaginous elements. Utilizing geometric morphometric tools, the reconstruction technique is validated through comparison of a reconstructed 9 year old pelvis, to the original CT data. A principal component analysis and an overlay of the two pelves provide a measure of the accuracy of the reconstructed model. Future work aims to investigate the biomechanical effects of any minor positional error on the bone's predicted structural properties through the use of finite element analysis. 相似文献
7.
C.C. Fagan C. Everard C.P. ODonnell G. Downey E.M. Sheehan C.M. Delahunty D.J. OCallaghan V. Howard 《Journal of food engineering》2007,80(4):1068-1077
The objective of this study was to determine the potential of mid-infrared spectroscopy coupled with multidimensional statistical analysis for the prediction of processed cheese instrumental texture and meltability attributes. Processed cheeses (n = 32) of varying composition were manufactured in a pilot plant. Following two and four weeks storage at 4 °C samples were analysed using texture profile analysis, two meltability tests (computer vision, Olson and Price) and mid-infrared spectroscopy (4000–640 cm−1). Partial least squares regression was used to develop predictive models for all measured attributes. Five attributes were successfully modelled with varying degrees of accuracy. The computer vision meltability model allowed for discrimination between high and low melt values (R2 = 0.64). The hardness and springiness models gave approximate quantitative results (R2 = 0.77) and the cohesiveness (R2 = 0.81) and Olson and Price meltability (R2 = 0.88) models gave good prediction results. 相似文献
8.
Fagan CC Ferreira TG Payne FA O'Donnell CP O'Callaghan DJ Castillo M 《Journal of dairy science》2011,94(11):5350-5358
A front-face fluorescence spectroscopy probe was installed in the wall of a laboratory-scale cheese vat. Excitation and emission filters were chosen for the selective detection of vitamin A, tryptophan, and riboflavin fluorescence. The evolution of the fluorescence of each fluorophore during milk coagulation and syneresis was monitored to determine if they had the potential to act as intrinsic tracers of syneresis and also coagulation. The fluorescence profiles for 2 of the fluorophores during coagulation could be divided into 3 sections relating to enzymatic hydrolysis of κ-casein, aggregation of casein micelles, and crosslinking. A parameter relating to coagulation kinetics was derived from the tryptophan and riboflavin profiles but this was not possible for the vitamin A response. The study also indicated that tryptophan and riboflavin may act as tracer molecules for syneresis, but this was not shown for vitamin A. The evolution of tryptophan and riboflavin fluorescence during syneresis followed a first-order reaction and had strong relationships with curd moisture and whey total solids content (r = 0.86-0.96). Simple 1- and 2-parameter models were developed to predict curd moisture content, curd yield, and whey total solids using parameters derived from the sensor profiles (standard error of prediction = 0.0005-0.394%; R2 = 0.963-0.999). The results of this study highlight the potential of tryptophan and riboflavin to act as intrinsic tracer molecules for noninvasive inline monitoring of milk coagulation and curd syneresis. Further work is required to validate these findings under a wider range of processing conditions. 相似文献
9.
Duchek Janet M.; Balota David A.; Tse Chi-Shing; Holtzman David M.; Fagan Anne M.; Goate Alison M. 《Canadian Metallurgical Quarterly》2009,23(6):746
This study explored differences in intraindividual variability in 3 attention tasks across a large sample of healthy older adults and individuals with very mild dementia of the Alzheimer’s type (DAT). Three groups of participants (healthy young adults, healthy older adults, very mild DAT) were administered 3 experimental measures of attentional selection and switching (Stroop, Simon, task switching). The results indicated that a measure of intraindividual variability, coefficient of variation (CoV; SD/M), increased across age and early stage DAT. The CoV in Stroop discriminated the performance of ε4 carriers from noncarriers in healthy older controls and the CoV in task switching was correlated with cerebrospinal fluid (CSF) biomarkers predictive of DAT. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.