Non Dependence of Drift Velocity of Electron on Length of Carbon Nanotubes, Dependence on Quantum State and Expression of Current Density

The field of carbon nano tubes (CNT) is an active area of research theoretically as well experimentallynbsp [1,2]. It is established fact that samples of single wall carbon nano tubes containing tubes with an arm chair wrapping have been produced and exhibit metallic behaviour. In this paper, the quantized value of electrical conductivity is used to show theoretically that the drift velocity of electron is independent of the length of CNT and lsquoVdrsquo, drift velocity varies inversely as the quantum state. From which we can express current density of electrons in CNT and can show current density too depends on quantum state. nbs

Highly Permeable Perfluorinated Sulfonic Acid Ionomers for Improved Electrochemical Devices: Insights into Structure-Property Relationships.

Rapid improvements in polymer-electrolyte fuel-cell (PEFC) performance have been driven by the development of commercially available ion-conducting polymers (ionomers) that are employed as membranes and catalyst binders in membrane-electrode assemblies. Commercially available ionomers are based on a perfluorinated chemistry comprised of a polytetrafluoroethylene (PTFE) matrix that imparts low gas permeability and high mechanical strength but introduces significant mass-transport losses in the electrodes. These transport losses currently limit PEFC performance, especially for low Pt loadings. In this study, we present a novel ionomer incorporating a glassy amorphous matrix based on a perfluoro(2-methylene-4-methyl-1,3-dioxolane) (PFMMD) backbone. The novel backbone chemistry induces structural changes in the ionomer, restricting ionomer domain swelling under hydration while disrupting matrix crystallinity. These structural changes slightly reduce proton conductivity while significantly improving gas permeability. The performance implications of this trade-off are assessed, which reveal the potential for substantial performance improvement by incorporation of highly permeable ionomers as the functional catalyst binder. These results underscore the significance of tailoring material chemistry to specific device requirements, where ionomer chemistry should be rationally designed to match the local transport requirements of the device architecture

Comprehensive Approach of Groundwater Resource Evaluation: A Case Study in the Chippewa Creek Watershed in Ohio

Author Institution: Department of Geological Sciences, State University of New York - New Paltz ; Department of Earth Science, University of Northern Iowa ; Department of Geology, University of AkronA groundwater resource evaluation of Chippewa Creek watershed in Wayne and Medina counties, OH, shows continued availability of groundwater for agriculture and domestic uses. Two major hydrogeologic units in this watershed supply groundwater. A 100 to 150 ft (30 to 46 m) thick outwash deposit of sand and gravel, occupying a buried valley underlying Chippewa Creek, forms a highly permeable aquifer for agricultural, municipal, and domestic purposes. In some areas bedrock aquifers, mostly composed of sandstone of Pennsylvanian and Mississippian age, are used for industrial and domestic purposes. Mean transmissivity of the outwash aquifer is 25,000 gpd/ft (310 mVday). The hydraulic conductivity of the aquifer has a mean value of 250 gpd/ft2 (10 m/day). The total calculated volume of annual net recharge is 4.2 x 108 ft3 (1.2 107 m3) and the mean specific capacity of the wells completed in aquifer is 5.0 gpm/ft (1.03 1/sec/m). The groundwater quality is suitable for drinking and agricultural use and contains mostly Ca++, Na+, K+ and HCO3~ ions. Groundwater pollution potential of the study area was evaluated using DRASTIC. Chippewa Creek watershed lies within the Glaciated Central Ground Water Region. Seven mappable units from DRASTIC were defined in the study area based on seven hydrogeologic settings. The units are: 1) 7Aa, glacial till over bedded sedimentary rocks (DRASTIC designation); 2) 7Ad, glacial till over sandstone; 3) 7Af, sand and gravel interbedded in glacial till; 4) 7Ba, outwash; 5) 7D, buried valley; 6) 7Eb, alluvium without overbank deposits; 7) 7Ec, alluvium over bedded sedimentary rocks. The outwash aquifer has a moderate to high pollution potential and the underlying sandstone and shale deposits show relatively low pollution potentials. The alluvium in valleys exhibits moderately high susceptibility to contamination

Primary intravenous chemotherapy for group D retinoblastoma: a 13-year retrospective analysis.

BACKGROUND: Eye salvage rate for group D retinoblastoma using intravenous chemotherapy (IVC) as a primary modality is <50%. To report on 13 years' experience with the use of primary IVC for group D retinoblastoma. METHODS: A retrospective analysis of 64 group D eyes (52 patients) treated with primary IVC, from 2002 to 2014. RESULTS: The median age at presentation was 11.0 months (mean: 18.6, range: 0.6-144.0), 35 (67%) patients had bilateral disease, 38 (73%) germline disease and 8 (15%) cases were familial. In addition to IVC, patients received a median number of three treatments (mean: 6, range: 0-24), including thermotherapy/cryotherapy, plaque radiotherapy, intra-ophthalmic artery chemotherapy (IAC) and/or intravitreous chemotherapy. External beam radiotherapy (EBRT) was used in five eyes, all of which were eventually enucleated. In a median follow-up time of 55 months (mean: 64, range: 14-156), 63% of eyes were salvaged. By the Kaplan-Meier survival analysis, globe salvage rate was 83%, 70%, 59% and 45% at 1, 3, 5 and 10 years, respectively. There were no cases of metastatic spread from intraocular retinoblastoma and no deaths. IVC-related adverse events included febrile neutropenia in 21 (40%) patients and anaphylactic reaction to carboplatin in 2 (4%), all conservatively resolved. Of the patients receiving IAC, third and sixth nerve palsies were documented in two (10%) and one (5%) eyes, respectively. CONCLUSIONS: Primary IVC for group D eyes, with adjuvant treatments as required, was found to be a safe and efficient approach, achieving 63% eye salvage rate, no metastatic spread from intraocular retinoblastoma and no deaths. IAC has now replaced EBRT as a successful salvage treatment

Search for long lived heaviest nuclei beyond the valley of stability

The existence of long lived superheavy nuclei (SHN) is controlled mainly by spontaneous fission and $\alpha$-decay processes. According to microscopic nuclear theory, spherical shell effects at Z=114, 120, 126 and N=184 provide the extra stability to such SHN to have long enough lifetime to be observed. To investigate whether the so-called "stability island" could really exist around the above Z, N values, the $\alpha$-decay half lives along with the spontaneous fission and $\beta$-decay half lives of such nuclei are studied. The $\alpha$-decay half lives of SHN with Z=102-120 are calculated in a quantum tunneling model with DDM3Y effective nuclear interaction using $Q_\alpha$ values from three different mass formulae prescribed by Koura, Uno, Tachibana, Yamada (KUTY), Myers, Swiatecki (MS) and Muntian, Hofmann, Patyk, Sobiczewski (MMM). Calculation of spontaneous fission (SF) half lives for the same SHN are carried out using a phenomenological formula and compared with SF half lives predicted by Smolanczuk {\it et al}. Possible source of discrepancy between the calculated $\alpha$-decay half lives of some nuclei and the experimental data of GSI, JINR-FLNR, RIKEN are discussed. In the region of Z=106-108 with N$\sim$ 160-164, the $\beta$-stable SHN $^{268}_{106}Sg_{162}$ is predicted to have highest $\alpha$-decay half life ($T_\alpha \sim 3.2hrs$) using $Q_\alpha$ value from MMM. Interestingly, it is much greater than the recently measured $T_\alpha$ ($\sim 22s$) of deformed doubly magic $^{270}_{108}Hs_{162}$ nucleus. A few fission-survived long-lived SHN which are either $\beta$-stable or having large $\beta$-decay half lives are predicted to exist near $^{294}110_{184}$, $^{293}110_{183}$, $^{296}112_{184}$ and $^{298}114_{184}$. These nuclei might decay predominantly through $\alpha$-particle emission.Comment: 14 pages, 6 figures, 1 tabl

Single-vehicle data of highway traffic - a statistical analysis

In the present paper single-vehicle data of highway traffic are analyzed in great detail. By using the single-vehicle data directly empirical time-headway distributions and speed-distance relations can be established. Both quantities yield relevant information about the microscopic states. Several fundamental diagrams are also presented, which are based on time-averaged quantities and compared with earlier empirical investigations. In the remaining part time-series analyses of the averaged as well as the single-vehicle data are carried out. The results will be used in order to propose objective criteria for an identification of the different traffic states, e.g. synchronized traffic.Comment: 12 pages, 19 figures, RevTe

Design, fabrication and demonstration of a 1x20 multimode interference splitter for parallel biosensing applications

This paper presents the experimental achievement of a silicon-on-insulator 1x20 MMI splitter andsimulation evaluations of the TE-like and TM-like mode MMI splitters for parallel biosensing applications. Device fabrication technology and optical characterisation results are provided