Large negative magnetoresistance and metal–insulator transition observed in MnO/C composite coatings grown on ceramic alumina by metalorganic chemical vapor deposition

MnO/C composite coatings were grown by the metalorganic chemical vapor deposition process on ceramic alumina in argon ambient. Characterization by various techniques confirms that these coatings are homogeneous composites comprising nanometer-sized MnO particles embedded in a matrix of nanometer-sized graphite. Components of the MnO/C composite coating crystalline disordered, but are electrically quite conductive. Resistance vs. temperature measurements show that coating resistance increases exponentially from a few hundred ohms at room temperature to a few megaohms at 30 K. Logarithmic plots of reduced activation energy vs. temperature show that the coating material undergoes a metal–insulator transition. The reduced activation energy exponent for the film under zero magnetic field was 2.1, which is unusually high, implying that conduction is suppressed at much faster rate than the Mott or the Efros–Shklovskii hopping mechanism. Magnetoconductance vs. magnetic field plots obtained at various temperatures show a high magnetoconductance (∼28.8%) at 100 K, which is unusually large for a disordered system, wherein magnetoresistance is attributed typically to weak localization. A plausible explanation for the unusual behavior observed in the carbonaceous disordered composite material is proposed.     

Numerical study of mixed convective heat transfer in a lid‐driven enclosure with rotating cylinders

A numerical simulation is performed to characterize the mixed convective transport in a three‐dimensional square lid‐driven enclosure with two rotating cylinders. The top wall is moving in the positive x‐direction, and the bottom wall is at a higher fixed temperature compared with all other isothermal walls. Both cylinders are rotating in its own plane about their centroidal axis. On the basis of rotation of both cylinders in clockwise or counter‐clockwise directions, four rotational models are studied. Various controlling parameters considered in the present study are Grashof number (10 ³ < Gr < 10 ⁵), rotating speed of the cylinder (5 < ω < 50), and the Reynolds number based on top wall movement is fixed to 100. The effect of cylinder rotation on the heat transfer of bottom wall is reported with the help of streamlines, contour plots of z‐component of vorticity, averaged and local Nusselt number, ratios of secondary flow and drag coefficient. It is observed that the heat transfer at the bottom wall is substantially dependent on the rotational model and rotational speed of the cylinder.     

Large distance flow-slide at Jono-Oge due to the 2018 Sulawesi Earthquake,Indonesia

There was a shallow earthquake in the Central Sulawesi province of Sulawesi island of Indonesia with a moment magnitude (Mw) 7.5 on 28th September 2018 at 18:02:44 local time. The event was preceded by major foreshocks and followed by aftershocks of significant magnitude. The epicenter of the main shock was in the Donggala regency of Minahasa peninsula of Central Sulawesi, approximately 70 km from the provincial capital of Palu. The earthquake was caused by the tectonic movement of the left lateral Palu- Koro fault within the Molucca Sea microplate, triggering major geotechnical failure and structural damage in Palu city and Sigi regency. Thousands of people died or are still unaccounted for, and countless others were injured. Balaroa, Petobo, Jono-Oge and Sibalaya were the worst hit mainly due to large-scale flow-slides and mud flows. It was the first time that such large-scale flow failures were triggered by an earthquake, and that the failure of very gentle sloping ground swept away whole localities. The objective of this research was to provide insight into the scale of ground failure and other infrastructural damage caused by the event, especially in Jono-Oge area, where the flow distance was longest. The authors performed preliminary and detailed surveys in the area twice by conducting Portable Dynamics Cone Penetration Test (PDCPT), collecting disturbed and undisturbed samples and using aerial drone (UAV) photography. The findings of the reconnaissance survey are described here along with subsequent data interpretation. Finally, the mechanism of the flow-slides is discussed.     

Full-program induction: verifying array programs sans loop invariants

International Journal on Software Tools for Technology Transfer - Arrays are commonly used in a variety of software to store and process data in loops. Automatically proving safety properties of...     

Design of Ultra-Low Power High-Q Single Ended Active Inductors for IF BPF of Receiver Frontend Using 130 nm BiCMOS Technology

Wireless Personal Communications - In this work, performance of conventional gyrator-C based active inductor is studied and two designs of single-ended active inductors based on modified gyrator-C...     

A 2.4 GHz Low Power Low Phase-Noise Enhanced FOM VCO for RF Applications Using 180 nm CMOS Technology

Wireless Personal Communications - Blur is the most common distortion in images, so it is significant to evaluate the quality of blur images. Considering the view saliency and multiscale...     

Chirality Dependent Charge Transfer Rate in Oligopeptides

It is shown that “spontaneous magnetization” occurs when chiral oligopeptides are attached to ferrocene and are self‐assembled on a gold substrate. As a result, the electron transfer, measured by electrochemistry, shows asymmetry in the reduction and oxidation rate constants; this asymmetry is reversed between the two enantiomers. The results can be explained by the chiral induced spin selectivity of the electron transfer. The measured magnetization shows high anisotropy and the “easy axis” of magnetization is along the molecular axis.     

Bias in somatic hypermutation of human VH genes

Translationally silent mutations, which are not antigen selected, of human VH6 Ig gene rearrangements isolated from human spleen were analyzed for bias to gain insight into intrinsic features of the mutation process. Sixty-three clones representing 38 VH6DJ rearrangements had an overall mutation frequency of 4.5%, a replacement/silent (R/S) mutation ratio of 2.1 and 167 unique silent mutations. The silent mutations showed bias in: (i) targeting to CDR1 and CDR2, (ii) an increased frequency of mutations of A compared to T nucleotide bases on the coding strand, and (iii) an increased frequency of transitions versus transversions. Bias of C-->G over C-->A, of G-->C over G-->T and of A-->C over A-->T transversions was also present. Hot spots of mutation were observed, some which corresponded to potential sites of stem-loop formation. The results suggest that the somatic mutation process in man may be targeted to the complementarity determining region for some V genes, exhibits specific base substitutions favoring transitions and specific types of transversions, and may be occurring on only one DNA strand.     

Two methods for privacy preserving data mining with malicious participants

Privacy preserving data mining addresses the need of multiple parties with private inputs to run a data mining algorithm and learn the results over the combined data without revealing any unnecessary information. Most of the existing cryptographic solutions to privacy-preserving data mining assume semi-honest participants. In theory, these solutions can be extended to the malicious model using standard techniques like commitment schemes and zero-knowledge proofs. However, these techniques are often expensive, especially when the data sizes are large. In this paper, we investigate alternative ways to convert solutions in the semi-honest model to the malicious model. We take two classical solutions as examples, one of which can be extended to the malicious model with only slight modifications while another requires a careful redesign of the protocol. In both cases, our solutions for the malicious model are much more efficient than the zero-knowledge proofs based solutions.     

Measurement of the longitudinal and transverse vibration frequencies of a rod by speckle interferometry

A heterodyne interferometric system was used to detect the normal and tangential components of the displacement at one point of a sample when it is vibrating freely in its natural modes, arising from transient excitation. A cylindrical aluminium rod was the test sample. An analysis of the spectrum associated with the in-plane and out-of-plane displacements made it possible to determine the values of the longitudinal and transverse natural frequencies.