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Institution

Rensselaer Polytechnic Institute

EducationTroy, New York, United States
About: Rensselaer Polytechnic Institute is a education organization based out in Troy, New York, United States. It is known for research contribution in the topics: Terahertz radiation & Population. The organization has 19024 authors who have published 39922 publications receiving 1414699 citations. The organization is also known as: RPI & Rensselaer Institute.


Papers
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Journal ArticleDOI
TL;DR: Collagen-CNT composite matrices may have utility as scaffolds in tissue engineering, or as components of biosensors or other medical devices, and Scanning electron microscopy showed physical interactions between CNT and collagen matrix.
Abstract: Carbon nanotubes (CNT) are attractive for use in fiber-reinforced composite materials due to their very high aspect ratio, combined with outstanding mechanical and electrical properties. Composite materials comprising a collagen matrix with embedded CNT were prepared by mixing solubilized Type I collagen with solutions of carboxylated single-walled carbon nanotubes (SWNT) at concentrations of 0, 0.2, 0.4, 0.8, and 2.0 weight percent. Living smooth muscle cells were incorporated at the time of collagen gelation to produce cell-seeded collagen-CNT composite matrices. Constructs containing 2.0 wt % CNT exhibited delayed gel compaction, relative to lower concentrations that compacted at the same rate as pure collagen controls. Cell viability in all constructs was consistently above 85% at both Day 3 and Day 7, whereas cell number in CNT-containing constructs was lower than in control constructs at Day 3, though statistically unchanged by Day 7. Scanning electron microscopy showed physical interactions between CNT and collagen matrix. Raman spectroscopy confirmed the presence of CNT at the expected diameter (0.85-1.30 nm), but did not indicate strong molecular interactions between the collagen and CNT components. Such collagen-CNT composite matrices may have utility as scaffolds in tissue engineering, or as components of biosensors or other medical devices.

376 citations

Journal ArticleDOI
TL;DR: In this paper, chemical interaction between molten basalt and felsic minerals of the continental crust (quartz, K-feldspar, and oligoclase) was examined in static and dynamic experiments at 1,200°-1,400° C.
Abstract: Chemical interaction between molten basalt and felsic minerals of the continental crust (quartz, K-feldspar, and oligoclase) was examined in static and dynamic experiments at 1,200°–1,400° C. Under circumstances of continuous stirring at 1,400°, β-quartz dissolves in tholeiite melt at a rate of 3.3×10−6 g/s per cm2 of contact area; at 1,300°, the solution rate is 1.5×10−6 g/cm{cm2}s. The feldspars are molten at the experimental conditions, and interact with contacting basalt melt by diffusion in the liquid state. This is a complex process characterized by rapid initial diffusion of alkalies to establish a distribution between felsic melt and basalt similar to that observed in cases of actual two-liquid equilibrium (both alkalies reach concentrations in the felsic melt 1.5–3 times those in the basalt). Alkali diffusion may be “uphill” or “downhill”, depending on which direction of net flux is required to produce a two-liquid type distribution. Once this distribution is attained, subsequent diffusion of all melt species is slow and apparently limited by the diffusivity of SiO2, which is 10−9-l0−10 cm2/s at 1,200° C. Interdiffusion experiments involving molten basalt and synthetic granite confirm the behavior illustrated by the feldspar/basalt results, and give similar SiO2 diffusivities. The solution rates and interdiffusion data can be used to model basalt contamination processes likely to occur in the continental crust. For the restricted case of solid quartzitic xenoliths, the uptake of SiO2 in a well-mixed basalt magma is quite fast: appreciable SiO2 contamination may occur over exposure times of only days to years. If basalt magma induces local melting of crustal rocks, the assimilation process becomes one of liquid-state interdiffusion. In this case, the varying diffusivities of ions and their differing preferences for silicic relative to basaltic melts can produce marked selective contamination effects. Selective contamination of ascending basaltic magmas is particularly likely in the case of K2O, which may be introduced in substantial amounts even when other elements remain unaffected. The Na2O content of mantle-derived magmas is buffered against contamination by crustal materials, and K2O is buffered against further increases once it reaches a level of 1–1.5 wt.%.

376 citations

Journal ArticleDOI
TL;DR: In this paper, the authors performed an analysis of spectra and photometry for 22,770 stars included in the third data release (DR3) of the SDSS.
Abstract: (Abridged) We perform an analysis of spectra and photometry for 22,770 stars included in the third data release (DR3) of the SDSS. We measure radial velocities and, based on a model-atmosphere analysis, derive estimates ofthe atmospheric parameters (effective temperature, surface gravity, and [Fe/H]) for each star. Stellar evolution models are then used to estimate distances. The SDSS sample covers a range in stellar brightness of 14 < V < 22, and comprises large numbers of F- and G-type stars from the thick-disk and halo populations (up to 100 kpc from the galactic plane), therefore including some of the oldest stars in the Milky Way. In agreement with previous results from the literature, we find that halo stars exhibit a broad range of iron abundances, with a peak at [Fe/H] ~ -1.4. This population exhibits essentially no galactic rotation. Thick-disk G-dwarf stars at distances from the galactic plane in the range 1<|z|<3 kpc show a much more compact metallicity distribution, with a maximum at [Fe/H] ~ -0.7, and a median galactic rotation velocity at that metallicity of 157 +/- 4 km/s (a lag relative to the thin disk of 63 km/s). A comparison of color indices and metal abundances with isochrones indicates that no significant star formation has taken place in the halo in the last ~ 11 Gyr, but there are thick-disk stars which are at least 2 Gyr younger. We find the metallicities of thick-disk stars to be nearly independent of galactocentric distance between 5 and 14 kpc, in contrast with the marked gradients found in the literature for the thin disk. No vertical metallicity gradient is apparent for the thick disk, but we detect a gradient inits rotational velocity of -16 +/- 4 km/s/kpc between 1 and 3 kpc from the plane.

375 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a critical analysis of the experimental data in terms of the potential mechanisms and show that, by accounting for linear particle aggregation, the well established effective medium theories for composite materials are capable of explaining the vast majority of the reported data without resorting to novel mechanisms such as Brownian motion induced nanoconvection, liquid layering at the interface, or near-field radiation.
Abstract: Over the last decade nanofluids (colloidal suspensions of solid nanoparticles) sparked excitement as well as controversy In particular, a number of researches reported dramatic increases of thermal conductivity with small nanoparticle loading, while others showed moderate increases consistent with the effective medium theories on well-dispersed conductive spheres Accordingly, the mechanism of thermal conductivity enhancement is a hotly debated topic We present a critical analysis of the experimental data in terms of the potential mechanisms and show that, by accounting for linear particle aggregation, the well established effective medium theories for composite materials are capable of explaining the vast majority of the reported data without resorting to novel mechanisms such as Brownian motion induced nanoconvection, liquid layering at the interface, or near-field radiation However, particle aggregation required to significantly enhance thermal conductivity, also increases fluid viscosity rendering the benefit of nanofluids to flow based cooling applications questionable

374 citations

Journal ArticleDOI
TL;DR: In this article, the authors test for differences in top management team composition (education, functional expertise, industry experience, and skill), dynamics (shared strategic cognition, potency, cohesion, and conflict) and performance (net cash flow and revenue growth) between a sample of 102 high-technology university-based start-ups and an otherwise equivalently matched sample of 154 independent hightechnology new ventures.

374 citations


Authors

Showing all 19133 results

NameH-indexPapersCitations
Pulickel M. Ajayan1761223136241
Zhenan Bao169865106571
Murray F. Brennan16192597087
Ashok Kumar1515654164086
Joseph R. Ecker14838194860
Bruce E. Logan14059177351
Shih-Fu Chang13091772346
Michael G. Rossmann12159453409
Richard P. Van Duyne11640979671
Michael Lynch11242263461
Angel Rubio11093052731
Alan Campbell10968753463
Boris I. Yakobson10744345174
O. C. Zienkiewicz10745571204
John R. Reynolds10560750027
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202334
2022177
20211,118
20201,356
20191,328
20181,245