Effect of Current Collector and Pyrolysis Temperature on the Electrochemical Performance of Photoresist Derived Carbon Films

SU-8, an epoxy based negative photoresist has been demonstrated as a potential precursor to fabricate thin films and three-dimensional micropatterned arrays in glassy carbon. However, the use of silicon wafer as a substrate cum collector limits their use in real battery devices. In accordance with the commercial lithium ion battery architecture and also owing to enhanced conductivity, we have successfully demonstrated the use of stainless steel (SS) wafer as a current collector to prepare binder free SU-8 derived carbon thin films. Standard carbon microelectromechanical systems (C-MEMS) process parameters were tuned to obtain a uniform, crack-free carbon thin film on SS wafer upon pyrolysis. Further, we varied the final pyrolysis temperature to examine its effect on the microstructure and composition as characterized with X-ray diffraction, Small angle X-ray scattering, Raman spectroscopy and CHNS-O elemental analyzer respectively. The microstructural changes in the carbon films at different pyrolysis temperature were then correlated with their electrochemical performance as investigated using galvanostat charge/discharge experiments, impedance spectroscopy and cyclic voltammetry. Selection of an appropriate current collector and optimizing the pyrolysis temperature yielded excellent cyclic stability and coulombic efficiency with 400 mAh g−1 reversible capacity after 100 cycles, nearly double to as reported in the literature

Photoresist Derived Carbon Films as High Capacity Anodes for Lithium Ion Battery

An epoxy-based negative photoresist (SU-8) was spin-coated on stainless steel (SS) wafers followed by two-step pyrolysis in inert atmosphere to yield dense carbon films to be used as anodes for lithium (Li) ion batteries. The selection of SS wafer substrates was in accordance with commercial Li ion battery architecture. Cyclic voltammograms confirm the passive layer formation by electrolyte decomposition in the initial cycle. Galvanostatic charge/discharge experiments in the range 0.01-3 V performed at a C-rate=0.1 C confirms the reversible intercalation of Li ions and shows higher gravimetric reversible capacity for these photoresist-derived carbon films on SS wafer substrates than graphite (400 mAh/g vs. 372 mAh/g for graphite). This high reversible capacity may be attributed to high disorder in photoresist derived-carbon as characterized by X-ray diffraction and Raman spectroscopy

Cross-correlation between PlanckPlanck CMB lensing potential and galaxy catalogues from HELP

We present the study of cross-correlation between Cosmic Microwave Background (CMB) gravitational lensing potential map released by the \textit{Planck} collaboration and photometric redshift galaxy catalogues from the \textit{Herschel} Extragalactic Legacy Project (HELP), divided into four sky patches: NGP, \textit{Herschel} Stripe-82, and two halves of SGP field, covering in total $\sim 660$ deg$^{2}$ of the sky. We estimate the galaxy linear bias parameter, $b_{0}$, from joint analysis of cross-power spectrum and galaxy auto-power spectrum using Maximum Likelihood Estimation technique to obtain values ranging from $0.70 \pm 0.01$ for SGP Part-2 to $1.02 \pm 0.02$ for SGP Part-1 field. We also estimate the amplitude of cross-correlation and find the values spanning from $0.67 \pm 0.18$ for SGP Part-2 to $0.80 \pm 0.23$ for SGP Part-1 field, respectively. For NGP and SGP Part-1 fields the amplitude is consistent with the expected value for the standard cosmological model within $\sim 1\,\sigma$, while for \textit{Herschel} Stripe-82 and SGP Part-2 we find the amplitude to be smaller than expected with $\sim 1.5\,\sigma$ and $\sim 2\,\sigma$ deviation, respectively. We perform several tests on various systematic errors to study the reason for the deviation, however, value of the amplitude turns out to be robust with respect to these errors. The only significant change in the amplitude is observed when we replace the minimum-variance CMB lensing map, used in the baseline analysis, by the lensing map derived from the CMB temperature map with deprojected thermal Sunyaev-Zeldovich signal.Comment: 15 pages, 13 figures, Published in MNRA

Underground Cordon by Microorganisms-Part-III Role of Soil Inhabiting Actinomycetes

Certain strains of soil inhabiting actinomycetes were found to substantially corrode aluminium alloy (54-S) which has bscn found tobe more resistant to bacterial or fungal corrosion in our earlier studies.These strains did not produce any corrosion on the mild steel and galvanised iron panels which were heavily corroded by bacteria and fungi. The corrosive isolates have been partialiy characterised after their isolation and purification. The extent of corrosion caused by eachstrain has been determined

Study of association of dry eye with diabetes mellitus

Background: Aim of the study was to evaluate the tear status in diabetes mellitus (DM) patient. Methods: This study was a prospective observational case control study. Eighty patients with DM aged from 50 to 80 years were compared with a group of 80 normal healthy age matched control group. A general ophthalmological check-up was performed. The main points of comparison were subjective complaints, objective findings on basic Schirmer test, break-up time, Rose Bengal test. Results: The results show that 27.5% of all diabetic subjects accompanied of dry eye symptoms, as against 6.25% of the control group. A mean BUT value was 15.5s and Standard Error was 0.20. In the control group mean BUT value was 14s and standard error was 0.23. Basic Schirmer test in DM group mean value was 9.50 mm and SE was 0.268. In the control group mean basic Schirmer test value was 15 mm and SE was 0.405. Rose Bengal test score in DM group, normal score (score <3) was found in 80% case and abnormal score (score >3) was found in 20%. In the control group, normal score was found in 93.75% and abnormal score was found in 6.25% case. Dry eye percentage in DM group 11.25% had definitive dry eye, 16.25% cases had possible dry eye and 72.5% cases had no dry eye. In control group 2.50% cases had definitive dry eye, 3.75% cases had possible dry eye and 93.75% had no dry eye. Conclusions: The study shows that dry eye is associated with DM

Ambient Temperature Growth and Superconducting Properties of Ti-V Alloy Thin Films

A study on the optimization of ambient temperature growth and superconducting properties of Ti-V alloy thin films grown on SiO2-coated Si substrate is reported here. These films have been synthesized by co-sputtering of Ti and V targets, and films having different Ti concentrations were deposited to get the optimized critical temperature (TC) of thin films close to the bulk value. The maximum TC of 5.2 K has been obtained in the Ti40V60 composition, which is further increased to 6.2 K when a 10 nm thick Ti underlayer is added below the Ti-V film. GIXRD measurements confirm the formation of Ti-V alloys in the desired crystal structure. The upper critical field (HC2) of the thin films has been estimated with the help of magnetotransport measurements. The utility of Ti-V alloy thin films in superconducting radiation detection applications is ascertained.Comment: 4 pages, 6 figure

Screening and Biochemical Characterization of Wheat Cultivars Resistance to Magnaporthe oryzae pv Triticum (MoT)

Global food security is seriously threatened due to increased frequency and occurrence of fungal diseases. One example is wheat blast caused by Magnaporthe oryzae is a fungal diseases of rice, wheat, and other grasses, that can destroy the whole food production to sustain millions of people. Wheat blast was first detected in february 2016 with a serious outbreak in Asia. Assessment of the available germplasms to stress tolerant/resistant is one of the best options for developing stress tolerant crop varieties. In this study, a total of sixteen wheat cultivars were collected and test their disease severity to blast pathogen Magnaporthe oryzae pv. Triticum (MoT). Among the varieties, BARI Gom 33 exhibited partially resistance against blast pathogen, whereas all other genotypes become susceptible to MoT. Different yield and yield contributing characters of both resistant and susceptible cultivars were also evaluated and found no significant differences among them. To understand the underlying mechanism of resistance in BARI Gom 33, antioxidant enzyme activity, concentration of reactive oxygen species and cellular damage after fungal infection were also evaluated and found that activities of ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) were higher in BARI Gom 33 than BARI Gom 25 and BARI Gom 31. The hydrogen peroxide (H2O2) and malondealdehyde (MDA) content in BARI Gom 33 was low compare to BARI Gom 25 and BARI Gom 31, which may due to greater increase of the APX, CAT and POD in resistant genotypes. Thus, it may suggest that a more efficient antioxidative defense system in BARI Gom 33 during the infection process of M. oryzae restricts the cell damage caused by the fungus. The identified genotypes can either be used directly in the blast prone area or as a source of resistance to further development of blast resistance high yielding wheat variety

Development of 0.2C-CrMnMoV Ultra High Strength Steel

A study was carried out to develop a low alloy ultra high strength steel by induction melting and thermomechanical treatment (TMT) containing alloying elements like carbon, manganese, molybdenum, chromium and vanadium. A base alloy was prepared with 0.24%C, 1.16% Mn, 0.23% Si, 5.61% Cr, 0.42%V, 1.01% Mo, 0.026%S and 0.032%P. It showed tensile strength of 1467 MPa, yield strength of about 1180 MPa, impact strength of 6.3J and elongation of 5.9% in as-tempered condition. Other alloy was prepared by addition of 0.054% titanium with the base composition. It displayed tensile strength, yield strength, impact toughness and % elongation of 1615 MPa, 1240 MPa, 8.2J and 6.15%, respectively. The optical, SEM and TEM microstructures confirmed that the base alloy and the titanium alloy consisted with tempered lath martensites. The remaining part of the ingot was further processed by the thermomechanical treatment. The ingots were rolled in two passes, initially at 950 C and subsequently at 850 C followed by immediate cooling in oil. The TMT plates of the base alloy confirmed the tensile strength of 1755 MPa, yield strength in excess of 1460 MPa and impact strength of 9.1J. The titanium added TMT plate displayed tensile strength of 1860 MPa, yield strength of 1580 MPa and impact strength of 10.1J. Microstructures of titanium added alloy consisted finer lath martensite and precipitates of titanium carbides/carbonitrides. It was observed that the addition of titanium significantly improved the mechanical properties of 0.2C-Cr Mn Mo V alloys and the mechanical properties were also improved significantly by thermomechanical treatment

Recovering missing slices of the discrete fourier transform using ghosts

The discrete Fourier transform (DFT) underpins the solution to many inverse problems commonly possessing missing or unmeasured frequency information. This incomplete coverage of the Fourier space always produces systematic artifacts called Ghosts. In this paper, a fast and exact method for deconvolving cyclic artifacts caused by missing slices of the DFT using redundant image regions is presented. The slices discussed here originate from the exact partitioning of the Discrete Fourier Transform (DFT) space, under the projective Discrete Radon Transform, called the discrete Fourier slice theorem. The method has a computational complexity of O(n\log-{2}n) (for an n=N\times N image) and is constructed from a new cyclic theory of Ghosts. This theory is also shown to unify several aspects of work done on Ghosts over the past three decades. This paper concludes with an application to fast, exact, non-iterative image reconstruction from a highly asymmetric set of rational angle projections that give rise to sets of sparse slices within the DFT

Fabrication of Resorcinol-Formaldehyde Xerogel based High Aspect Ratio 3-D Hierarchical C-MEMS Structures

We demonstrate a novel method to fabricate arrays of resorcinol- formaldehyde xerogel (RFX) based high aspect ratio (HAR) three- dimensional (3-D) hierarchical C-MEMS structures. Starting from a master pattern of HAR 3-D posts fabricated in SU-8 negative photoresist by photolithography, a negative PDMS stamp with arrays of holes was prepared by micromolding. The PDMS stamp was then used to fabricate HAR 3-D RFX posts by replica molding. The 3-D RFX posts thus fabricated were electrosprayed with SU-8 or an RF sol in the form of submicron or nano sized droplets and followed by pyrolysis to yield HAR 3-D hierarchical carbon posts. To characterize their use in C-MEMS based batteries, galvanostatic (charge and discharge) experiments on RFX derived carbon showed that it can be reversibly intercalated with Li ions and possesses superior intercalation properties as compared to SU- 8 derived carbon which is a widely used material in C-MEMS