This paper studies flow and heat transfer of nanofluids over a rotating disk with uniform stretching rate. Three types of nanoparticles-Cu, Al2O3 and CuO-with water-based nanofluids are considered. ...The governing equations are reduced by Von Karman transformation and then solved by the homotopy analysis method (HAM), which is in close agreement with numerical results. Results indicate that with increasing in stretching strength parameter, the skin friction and the local Nusselt number, the velocity in radial and axial directions increase, whereas the velocity in tangential direction and the thermal boundary layer thickness decrease, respectively. Moreover, the effects of volume fraction and types of nanofluids on velocity and temperature fields are also analyzed.
With the development of 60 GHz technology, data centers are going to be wireless. A fundamental challenge in wireless data center networking is how to efficiently use 60 GHz wireless technology to ...improve the performance. Many existing works have been proposed for this, but most of them do not perform well in connectivity or may not be flexible for different environments in data centers. This paper presents Graphite, a novel network structure that has many desirable features for wireless data centers. The whole architecture can be suitable for several different deployments of data centers. In Graphite, the problem of link blockage can be properly solved. Graphite makes best use of the propagation distance of 60 GHz and allows one server to communicate with as many other servers as possible. Graphite also improves the average node degree, which is more than any other existing wireless topologies on the same condition. Furthermore, Graphite can be suitable for data center with different deployments. We build a small testbed of Graphite to demonstrate its ability to solve the problem of link blockage. Results from theoretical analysis and extensive evaluations show that Graphite is a viable wireless topology for data center networks.
In the work, hollow nanoporous Au/Pt core–shell (H-PtAu) catalysts with nanochannels were prepared with different sizes of gold nanoparticles of a narrow size distribution in the range of 1.8 ± 0.3, ...3.2 ± 0.3 and 4.6 ± 0.5 nm. The hollow spheres were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and an energy-dispersive X-ray (EDX) analyzer. The electrochemical methods by cyclic voltammetric and chronoamperometry demonstrate that the catalytic performance of hollow nanoporous Au/Pt sphere electrocatalysts increases with the decrease of Au particles size in the samples. The nanoporous hollow structure of the electrocatalysts improves the efficiency for electro-oxidation of methanol and ethanol. More importantly, the nanoporous H-PtAu electrocatalysts have a higher catalytic activity and better steady-state performance for ethanol oxidation than methanol.
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•A facile strategy using TiO2 was successful adopted to form H-PtAu by one step.•The utilization of Pt atoms was improved due to hollow and nanoporous structure.•Nanoporous H-PtAu catalysts enhance electro-catalytic activities towards DAFCs.•The catalytic performance of H-PtAu increases with Au particles size decreasing.
•Build a large-scale 3D shape retrieval benchmark that supports multi-modal queries.•Evaluate the 26 3D shape retrieval methods using 3 types of metrics.•Solicit and identify state-of-the-art methods ...and promising related techniques.•Perform detailed analysis on diverse methods w.r.t accuracy and efficiency.•Make benchmark and evaluation tools freely available to the community.
Large-scale 3D shape retrieval has become an important research direction in content-based 3D shape retrieval. To promote this research area, two Shape Retrieval Contest (SHREC) tracks on large scale comprehensive and sketch-based 3D model retrieval have been organized by us in 2014. Both tracks were based on a unified large-scale benchmark that supports multimodal queries (3D models and sketches). This benchmark contains 13680 sketches and 8987 3D models, divided into 171 distinct classes. It was compiled to be a superset of existing benchmarks and presents a new challenge to retrieval methods as it comprises generic models as well as domain-specific model types. Twelve and six distinct 3D shape retrieval methods have competed with each other in these two contests, respectively. To measure and compare the performance of the participating and other promising Query-by-Model or Query-by-Sketch 3D shape retrieval methods and to solicit state-of-the-art approaches, we perform a more comprehensive comparison of twenty-six (eighteen originally participating algorithms and eight additional state-of-the-art or new) retrieval methods by evaluating them on the common benchmark. The benchmark, results, and evaluation tools are publicly available at our websites (http://www.itl.nist.gov/iad/vug/sharp/contest/2014/Generic3D/, 2014, http://www.itl.nist.gov/iad/vug/sharp/contest/2014/SBR/, 2014).
In western China coal mines, the mining-induced caving zone is regarded as a main pathway for water and sand inrush mixture hazards. The paper experimentally studied the flow behavior and the ...mechanism of water and sand mixture through mining-induced caving zones. Transport experiments are performed by using a laboratory-scale model, and the caving zone is modelled by using different sizes of glass beads. Four different sand sizes are used for the sand layer. The test results reveal that the mass flow rate of sand and water mixture increases with the increase of the initial water head. And an equation is proposed for the mass flow rate of sand and water mixtures that correctly reproduces the data for all the conditions. In addition, the sudden decreases in water head loss is monitored at the commencement of the water and sand flow, which would result in a large number of sand particles that rapidly start up and make the kinetic energy transfer from water to sand.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants (BFRs) and has been frequently detected in the environment and biota. Recent studies have found that ...derivatives of TBBPA, such as TBBPA bis(allyl) ether (TBBPA BAE) and TBBPA bis(2,3-dibromopropyl) ether (TBBPA BDBPE) are present in various environmental compartments. In this work, using liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) and liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC–Q-TOF-MS), TBBPA allyl ether (TBBPA AE) and TBBPA 2,3-dibromopropyl ether (TBBPA DBPE) were identified in environmental samples and further confirmed by synthesized standards. Soil, sediment, rice hull, and earthworm samples collected near a BFR manufacturing plant were found to contain these two compounds. In sediments, the concentrations of TBBPA AE and TBBPA DBPE ranged from 1.0 to 346.6 ng/g of dry weight (dw) and from 0.7 to 292.7 ng/g of dw, respectively. TBBPA AE and TBBPA DBPE in earthworm and rice hull samples were similar to soil samples, which ranged from below the method limit of detection (LOD, <0.002 ng/g of dw) to 0.064 ng/g of dw and from below the LOD (<0.008 ng/g of dw) to 0.58 ng/g of dw, respectively. Furthermore, mollusks collected from the Chinese Bohai Sea were used as a bioindicator to investigate the occurrence and distribution of these compounds in the coastal environment. The detection frequencies of TBBPA AE and TBBPA DBPE were 41 and 32%, respectively, and the concentrations ranged from below LOD (<0.003 ng/g of dw) to 0.54 ng/g of dw, with an average of 0.09 ng/g of dw, for TBBPA AE, and from below LOD (<0.008 ng/g of dw) to 1.41 ng/g of dw, with an average of 0.15 ng/g of dw, for TBBPA DBPE.
The optimal timing of radiotherapy (RT) with respect to surgery remains controversial for locally advanced non-small cell lung cancer (LA NSCLC) undergoing surgery and the long-term effect of ...neoadjuvant RT, adjuvant RT, and chemotherapy-only on survival is unknown.
A retrospective study with Greedy 5 → 1 Digit propensity score matching technique was performed for locally advanced NSCLC patients identified from the Surveillance, Epidemiology, and End Results (SEER) database during 2004 to 2012. Kaplan-Meier and the log-rank test were conducted to compare NSCLC-specific survival. Cox proportional hazards multivariable regression was performed to assess the impact of different treatment regimens on cancer-specific mortality after adjustment for demographic factors, histology type, tumor grade, tumor size, nodal stage, and extent of resection.
One thousand, two hundred and seventy-eight locally advanced NSCLC patients undergoing surgery were identified after propensity matching. Cox regression analyses showed the risk of cancer-specific mortality is not significantly different among neoadjuvant RT, adjuvant RT, and chemotherapy-only. Subgroup analyses showed that for patients with T1/2 & N2/3, the surgery plus chemotherapy-only group showed markedly higher mortality risk (HR = 1.42, 95%CI:1.10-1.83) than the neoadjuvant RT group. Other risk factors include older age, higher tumor grade, larger tumor size, and greater lymph node involvement.
The findings of this study suggest that the benefit of additional neoadjuvant or adjuvant RT to chemotherapy may be linked to a proper selection of LA NSCLC patients who undergo surgery. The timing of radiotherapy should be decided on the premise of fully considering patients' condition and the quality of life after treatment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper studies MHD flow and radiation heat transfer of nanofluids against a flat plate in porous medium with the effects of variable surface heat flux and first-order chemical reaction. Three ...types of nanoparticles Cu, Al2O3 and Ag are investigated. Similarity transformations are applied to reduce the governing partial differential equations with boundary conditions into a system of ordinary differential equations over a semi-infinite interval. An efficient analytical approach based on differential transformation base functions method (DTM-BF) for unbounded domains is performed to give approximate solutions which are verified by numerical ones, showing close agreement. The effects of the solid volume fraction, types of nanoparticles, permeability, magnetic field, chemical reaction, Schmidt number, radiation and suction/blowing on velocity, temperature and concentration fields are graphically illustrated and analyzed in detail.
The efficient and concise synthesis of (−)-orthodiffenes A and C has been accomplished for the first time in eight steps from readily available chiral synthons, d-mannose and d-ethyl lactate. Our ...work confirmed the complete structure of orthodiffenes A and C, including their absolute stereochemistry. The key steps of our total synthesis involved cis-fused tetrahydrofuran cyclization, one-pot deprotection–lactonization, and intramolecular benzoyl migration according to a biosynthetic hypothesis of orthodiffenes.
Our experiment reported here adopts water, alcohol (100 %), carboxymethyl cellulose (CMC) aqueous solution with different concentrations as the base-fluid of nano-fluids. We show diffusion, ...aggregation and precipitation of nano-size particles in the optical quartz glass Petri dishes filled with nano-fluids flat with the help of a rotating cone. The experimental results illustrate that nanoparticles are preferably suspended in CMC aqueous solution than in water or alcohol, which means the effective Hamaker constant of water- or alcohol-particle suspensions is bigger than that of CMC-particle suspension. In the experiment with CMC as the base solution, increasing the viscosity of the solution can alleviate the settling velocity of particles and make the suspension better. The experiment also discovers that in static condition, the mutual attractive force between nanoparticles plays an important role in the suspension; however, if external forces, which are higher than the attraction, exist, they are decisive parts. In addition, Al
2
O
3
solution is much more sensitive than the Cu solution with the varying concentration and status in the experiment because the density of Al
2
O
3
particles is smaller than that of Cu-nanoparticles.
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