Fishtail effect and vortex dynamics in LiFeAs single crystals

We investigate the fishtail effect, critical current density ($J_c$) and vortex dynamics in LiFeAs single crystals. The sample exhibits a second peak (SP) in the magnetization loop only with the field $||$ c-axis. We calculate a reasonably high $J_c$, however, values are lower than in 'Ba-122' and '1111'-type FeAs-compounds. Magnetic relaxation data imply a strong pinning which appears not to be due to conventional defects. Instead, its behavior is similar to that of the triplet superconductor Sr$_2$RuO$_4$. Our data suggest that the origin of the SP may be related to a vortex lattice phase transition. We have constructed the vortex phase diagram for LiFeAs on the field-temperature plane.Comment: 5 pages, 5 figure

Value Added: Technique for Corporate Performance Measurement Under Social Perspective

Financial Analysts consider as profit the most important measure of business performance. Profit may be expressed in terms of money value and measured as sales margin percentage or be calculated as return of investment. These, in any form, are used as basis for measure of business performance. In recent years, considerable interest have been shown in the use of value added as an alternative or additional approach to measure the operational efficiency and profitability of a business. A lot of discussion have been going on about reporting the performance of an organization in terms of value added rather than conventional profit or loss. The information disclosed by the Statement of Value Added, based on Value Added Accounting and reporting is considered to be much more useful than that disclosed by the conventional profit and loss account in providing a realistic basis for measuring the economic performance of an organization. The concept has received great attention in accounting practices with the emergence of large corporations having significant bearing on the society and finally on the economy for multi-dimensional impact over and above the owners. Value added system is a very useful measure of judging the performance of an enterprise for managerial decision-making and for inter-firm comparison

Effect of tool geometry on dimensional accuracy and surface finish of turned parts

This paper investigates, experimentally and analytically, the influence of tool geometry on two major dimensional accuracy characteristics of a turned part—diameter error and circularity—and the surface finish characteristic arithmetic average. Data were analysed via two methods: Pareto ANOVA and Taguchi method. The findings indicate that the two selected tool geometry parameters—insert shape and nose radius—have a considerable effect on diameter error (total contribution 67.0%) and minor effects on surface finish (total contribution 11.6%) and circularity (total contribution 7.5%). The major contributor to surface finish is feed rate, whereas circularity is dominated by interaction effects

Transverse spin relaxation time in organic molecules

We report a measurement of the ensemble-averaged transverse spin relaxation time (T∗2) in bulk and few molecules of the organic semiconductor tris-(8-hydroxyquinolinolato aluminum) or Alq3. This system exhibits two characteristic T∗2 times: the longer of which is temperature independent and the shorter is temperature dependent, indicating that the latter is most likely limited by spin-phonon interaction. Based on the measured data, we infer that the single-particle T2 time is probably long enough to meet Knill’s criterion for fault-tolerant quantum computing even at room temperature. Alq3 is also an optically active organic, and we propose a simple optical scheme for spin qubit readout. Moreover, we found that the temperature-dependent T∗2 time is considerably shorter in bulk Alq3powder than in few molecules confined in 1–2-nm-sized cavities. Because carriers in organic molecules are localized over individual molecules or atoms but the phonons are delocalized, we believe that this feature is caused by phonon bottleneck effect

DNA amplified fingerprinting, a useful tool for determination of genetic origin and diversity analysis in Citrus

We used three short repetitive nucleotide sequences [(GTG)5, (TAC)5, and (GACA)4] either as radiolabeled probes for hybridization with restricted Citrus DNA or as single primers in polymerase chain reaction amplification experiments with total genomic DNA. We tested the ability of the sequences to discriminate between seedlings of zygotic or nuclear origin in the progeny of a Volkamer lemon #Citrus volkameriana# Ten. & Pasq.) tree. The genetic variability within two species [#Citrus sinensis# (L.) Osbeck (sweet oranges) and #Citrus reticulata# Blanco and relatives (mandarins)] was evaluated. DNA amplified figerprinting with single primers was the more successful technique for discriminating between nucellular and zygotic seedlings. Although we were not able to distinguish among 10 cultivars of #C. sinensis#, all 10 #C. reticulata# cultivars tested were distinguishable. However, it still is difficult to identify the putative parents of a hybrid plant when the two parental genomes are closely related. (Résumé d'auteur

Size-dependent electronic-transport mechanism and sign reversal of magnetoresistance in Nd0.5Sr0.5CoO3

A detailed investigation of electronic-transport properties of Nd0.5Sr0.5CoO3 has been carried out as a function of grain size ranging from micrometer order down to an average size of 28 nm. Interestingly, we observe a size induced metal-insulator transition in the lowest grain size sample while the bulk-like sample is metallic in the whole measured temperature regime. An analysis of the temperature dependent resistivity in the metallic regime reveals that the electron-electron interaction is the dominating mechanism while other processes like electron-magnon and electron-phonon scatterings are also likely to be present. The fascinating observation of enhanced low temperature upturn and minimum in resistivity on reduction of grain size is found due to electron-electron interaction (quantum interference effect). This effect is attributed to enhanced disorder on reduction of grain size. Interestingly, we observed a cross over from positive to negative magnetoresistance in the low temperature regime as the grain size is reduced. This observed sign reversal is attributed to enhanced phase separation on decreasing the grain size of the cobaltite