Seed dormancy overcoming and seed coat structure change in Leucaena leucocephala and Acacia nilotica

Mulik Abbaker Ibrahim Yousif,Yan Rong Wang,Chen Dali 한국산림과학회 2020 Forest Science And Technology Vol.16 No.1

Leucaena leucocephala and Acacia nilotica are two arboreal legumes with several uses in agriculture, nutritious forage and livelihoods, fence posts, wood production, biofuel production, charcoal, firewood, shading, hedges, windbreaks, and improvement of soil fertility. The seed dormancy is common in Leucaena and Acacia species, and it creates difficulties in seed testing and planting. The aim of this study is to determine the effective methods of sulfuric acid and hot water due to overcoming dormancy in seeds of those species. Most pretreatments significantly (p<0.05) reduced hard seed content and enhanced germination percentage when compared to nontreated seeds. Effectiveness of water and acid pretreatments increased when increasing in duration time from 3 to 60 min. The best recommended time pretreatment of sulfuric acid 60 min for A. nilotica, and 3 min of hot water for Leucaena. These treatments all reduced hard seeds to 0% and did not cause damage to the seeds during the germination. Further, the lens and hilum both were identified as primary sites for water uptake into the seeds of Leucaena. Whereas, the lens was recognized as the original site of water intake in A. nilotica. In addition, the seed coat anatomy identified that the palisade epidermal layer was dense, and thickness tissue had been prevented imbibition of water in Leucaena and A. nilotica.

Electrochemical determination of semicarbazide on cobalt oxide nanoparticles: Implication towards environmental monitoring

Balaji B. Mulik,Ajay V. Munde,Raviraj P. Dighole,Bhaskar R. Sathe 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.93 No.-

The electrochemical determination of semicarbazide (SCB) executed by using cobalt oxide (Co3O4)nanoparticle modified electrode which was fabricated by using simple precipitation method. The assynthesizednanoparticles have been well characterised by X-ray diffraction (XRD), Furrier transforminfra-red (FTIR), UV-visible (UV-Vis) spectroscopic techniques, energy dispersive analysis of X-ray(EDAX), BET surface area, thermogravimetric (TG) analysis and transmission electron microscopic (TEM)techniques. The XRD shows face centred cubic (FCC) structure, the FTIR demonstrated a major bandsappeared at 574 cm 1 and 669 cm 1 are suggesting the (Co-O) vibrational mode of Co3O4. The TEM ofCo3O4 NPs has been confirmed its ultra-small particle size is of2 nm 0.5 nm. Whereas, EDAX showsthe only cobalt and oxygen are available confirms Co3O4 having high BET surface area. The fabricatedCo3O4 acted as a highly sensitive electrochemical sensor for the determination of SCB by using linearSweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) in0.5 M KOH solution. Significantly, anodic onset potential observed at 0.2 V vs. SCE, linear range of scanrate and concentration (1 mM–100 mM) with (LOD 0.13 and LOQ 0.46) and high current and potentialstability with pH dependent behaviour confirms Co3O4 based electrocatalytic system is good for oxidativedetermination of SCB. The selectivity of the sensor also tested by using mixture of other environmentalactive species with SCB by using LSV measurements. This proposed system is applicable in food andpharmaceutical industries for the determination of SCB as an amperometric sensor.

Microwave assisted processing of silver thick films for microelectronic applications

Rane, Sunit,Bhatkar, Rushna,Mulik, Uttam,Amalnerkar, Dinesh Techno-Press 2013 Advances in materials research Vol.2 No.3

This paper aims to focus on the microwave processing of thick films which is a fast, cheap technique and could be the alternative to the currently used conventional high temperature processing technique. Microwave processing has gained worldwide acceptance as a novel method for heating and sintering a variety of materials, as it offers specific advantages in terms of speed, energy efficiency, process simplicity, finer microstructures and lower environmental hazards. Silver conducting thick films were prepared and processed in the household microwave oven. The films sintered at different time period by keeping the other parameter such as microwave power, film thickness etc constant. The microstructure analysis revealed that the surface morphology of the microwave processed films become compact with respect to the processing time. The sheet resistance for microwave sintered silver films is in the range of 0.003 to $1.207{\Omega}/{\Box}$ where as the films fired at 750 and $850^{\circ}C$ showed the resistance of 0.009 and $0.003{\Omega}/{\Box}$ which can be comparable. The results revealed that the microstructure of the microwave sintered films has more uniform and compact surface than that of the conventionally fired films. The paper reports upon the preparation of silver thick film by screen printing technique and processing the same by microwave which also compared with the conventionally processed thick films.

Synergistic Effect of In-Situ Al-7075/Al3Ti Metal Matrix Composites Prepared via Stir-Assisted Ultrasonic Melt Processing Under Dynamic Nucleation

S. V. Sujith,Hansoo Kim,Rahul S. Mulik,Hyeonwoo Park,Joonho Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

Owing to the high propensity for particle agglomeration, the fabrication of aluminum matrix composites with uniformdistribution using casting routes is extremely difficult. In this study, the in-situ development of the Al3Tireinforcing phaseby employing stir-assisted ultrasonic treatment was utilized to improve the homogeneity, wettability, and thermodynamicstability of the reinforcing particles in an Al-7075 alloy matrix. The in-situ Al3Tiparticles acted as heterogeneous nucleationsites and facilitated grain refinement to form a non-dendritic globular structure compared with the dendritic cells of the basealloy. The grain size of the α-Al dendrites reduced from 160 μm to 65, 50, and 40 μm with the addition of 2, 5, and 7 wt%Al3Ti,respectively. The reduction in the porosity of the composites and the improvement of the particle homogenizationwere due to cavitation-induced de-agglomeration and the degassing effect. The formation of a robust and clean interfacebetween the Al3Tiparticles and Al alloy via ultrasonic vibration improved the integrity of the composites compared withthat of the base alloy. The thermal expansion mismatch between the Al3Tiparticles and Al alloy contributed significantly tothe improved mechanical properties of the composites.

Electrically Conductive Photopatternable Silver Paste for High-Frequency Ring Resonator and Band-Pass Filter

Umarji, G.,Qureshi, N.,Gosavi, S.,Mulik, U.,Kulkarni, A.,Kim, T.,Amalnerkar, D. Springer Science + Business Media 2017 Journal of electronic materials Vol.46 No.2

<P>In conventional thick-film technology, there are often problems associated with poor edges, rough surfaces, and reproducibility due to process limitations, especially for high-frequency applications. These difficulties can be circumvented by using thin-film technology, but process cost and complexity remain major concerns. In this context, photopatternable thick-film technology can offer a viable alternative due to its Newtonian rheology, which can facilitate formation of the required sharp edges. We present herein a unique attempt to formulate a photopatternable silver paste with organic (photosensitive polymer) to inorganic (silver and glass) ratio of 30:70, developed in-house by us for fabrication of thick-film-based ring resonator and band-pass filter components. The ring resonator and band-pass component structures were realized by exposing screen-printed film to ultraviolet light at wavelength of 315 nm to 400 nm for 30 s to crosslink the photosensitive polymer. The pattern was subsequently developed using 1% sodium carbonate aqueous solution. For comparison, conventional silver and silver-palladium thick films were produced using in-house formulations. The surface topology and microstructural features were examined by stereomicroscopy and scanning electron microscopy. The smoothness and edge definition of the film were assessed by profilometry. The resistivity of the samples was observed and remained in the range from 3.4 mu a'broken vertical bar cm to 3.6 mu a'broken vertical bar cm. The electrical properties were compared by measuring the insertion loss characteristics. The results revealed that the ring resonator fabricated using the photopatternable silver paste exhibited better high-frequency properties compared with components based on conventional silver or silver-palladium paste, especially in terms of the resonant frequency of 10.1 GHz (versus 10 GHz designed) with bandwidth of 80 MHz. Additionally, the band-pass filter fabricated using the photopatternable silver paste displayed better center frequency (f (0) = 10.588 GHz) and comparable ripple and attenuation bandwidth performance on par with Cu thin film.</P>

On the Estimation and Control of Welding Distortion of Guide Blade Carrier for a 660 MW Turbine by Using Inherent Strain Method

A. Vishvesha, C. Pandey,M. M. Mahapatra,R. S. Mulik 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.1

While predicting the welding distortion for a complex welded structure like the guide blade carrier assembly of power generation turbine, the traditional thermo-mechanical models commonly utilized for geometrically simple welded butt and T joints may not be adequate. For large and complex welded structures,the thermo-mechanical elasto-plastic analysis can be computationally prohibitive. Other than simplistic butt and T joints, the aforementioned distortion prediction technique is not so suitable to provide reliable results when applied to large complex 3-D welded structures. Hence, inherent strain method is proposed here to predict distortion in an outer ringof GBC (Guide Blade Carrier) of a steam turbine. Such welded outer rings of GBC are large welded structures having many welded joints of different weld geometries at several planes. In the present study, inherent strain based technique was utilized for the aforementioned welded structure in elastic finite element analysis for the accurate prediction of 3-D distortion patterns with reduced computational time. The predicted and measured values of 3- D distortions of GBC were observed to be in good agreement with the ones provided from the shop floor, indicating the adequacy of inherent strain based method for the prediction of welding distortion in large and complex welded structures. As part of this investigation, a suitable welding fixture was also designed and welding sequence was modified, which were verified through inherent stain method to aid in minimizing the distortion of welded GBC.

Measurements of Fission Product Yield in the Neutron-induced Fission of 238U with Average Energies of 9.35 MeV and 12.52 MeV

Sadhana Mukerji,Pritam Das Krishnani,Byrapura Siddaramaiah Shivashankar,Vikas Kaluram Mulik,Saraswatula Venkat Suryanarayana,Haladhara Naik,Ashok Goswami 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.1

The yields of various fission products in the neutron-induced fission of 238U with the flux-weightedaveragedneutron energies of 9.35 MeV and 12.52 MeV were determined by using an off-line gammarayspectroscopic technique. The neutrons were generated using the 7Li(p, n) reaction at BhabhaAtomic Research Centre-Tata Institute of Fundamental Research Pelletron facility, Mumbai. Thegamma- ray activities of the fission products were counted in a highly-shielded HPGe detector overa period of several weeks to identify the decaying fission products. At both the neutron energies, thefission-yield values are reported for twelve fission product. The results obtained from the presentwork have been compared with the similar data for mono-energetic neutrons of comparable energyfrom the literature and are found to be in good agreement. The peak-to-valley (P/V) ratios werecalculated from the fission-yield data and were found to decreases for neutron energy from 9.35 to12.52 MeV, which indicates the role of excitation energy. The effect of the nuclear structure on thefission product-yield is discussed.

In situ preparation of a novel organo-inorganic 6,13-pentacenequinone-TiO2 coupled semiconductor nanosystem: a new visible light active photocatalyst for hydrogen generation

Pandit, V.,Arbuj, S.,Hawaldar, R.,Kshirsagar, P.,Mulik, U.,Gosavi, S.,Park, C. J.,Kale, B. Royal Society of Chemistry 2015 Journal of Materials Chemistry A Vol.3 No.8

<P>Previous studies related to the synthesis of stable UV-visible light active photocatalysts for hydrogen generation have been limited to inorganic semiconductors and their nano-and hetero-structures. We demonstrate here the use of an organo-inorganic 6,13-pentacenequinone (PQ)-TiO2 coupled semiconductor nanosystem as an efficient photocatalyst active in visible light for the production of hydrogen. Anatase TiO2 nanoparticles (3-5 nm) were uniformly decorated on thin sheets of monoclinic PQ by an in situ solvothermal method. These as-prepared PQ-TiO2 coupled semiconductor nanosystems had a band gap in the range 2.7-2.8 eV. The strong emission at 590 nm can be attributed to the transfer of electrons from the LUMO energy level of TiO2 to combine with the holes present in the HOMO level of PQ. This electron-hole recombination makes availability of electrons and holes in LUMO of PQ and HOMO of TiO2, respectively. This hybrid semiconductor coupled nanosystem resulted in a rate of hydrogen evolution of 36 456 mu mol h(-1) g(-1) from H2S under UV-visible light; this is four times higher than the rate obtained with TiO2 in earlier reports of UV-visible light active photocatalysts. These results open up a new path to explore inorganic systems coupled with PQ as new photoactive hybrid catalysts in a number of chemical and physicochemical processes.</P>

Thermal Barrier Coatings—A State of the Art Review

Jayant Gopal Thakare,Chandan Pandey,M. M. Mahapatra,R. S. Mulik 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

Thermal barrier coatings (TBCs) have seen considerable advancement since the initial testing and development of thermalspray coating. Thermal barrier coatings are currently been utilized in various engineering areas which include internal combustion engines, gas turbine blades of jet engines, pyrochemical reprocessing units and many more. The development of newmaterials, deposition techniques is targeted at improving the life of the underlying substrate. Hence, the performance of thecoating plays a vital role in improving the life of substrate. The scope for advancement in thermal barrier coatings is veryhigh and continuous eforts are being made to produce improved and durable coatings. Thermal barrier coatings have thepotential to address long term and short-term problems in gas turbine, internal combustion and power generation industry. The study of thermal barrier coating material, performance and life estimation is a critical factor that should be understood tointroduce any advancement. The present review gives an overview of the thermal spraying techniques and current advancements in materials, mechanical properties, understanding the high temperature performance, residual stress in the coating,understanding the failure mechanisms and life prediction models for coatings.

Novel synthesis of efficient counter electrode by facile arrested precipitation technique (APT)

Jadhav, S. S.,Mali, S. S.,Hong, C. K.,Patil, P. S.,Bhosale, P. N.,Mulik, G. N. Springer Science + Business Media 2016 Journal of materials science. Materials in electro Vol.27 No.4

<P>In the present investigation, we have successfully synthesized nanogranular thin film of copper sulfoselenide Cu-2(S, Se) as efficient counter electrode to CdS0.7Se0.3 photoanode by facile arrested precipitation technique (APT). The deposited photoanode was annealed at 150 A degrees C in vacuum oven and used for further characterization. Optical absorption study suggested the band gap energy of photoanode is 1.75 eV. X-ray diffraction results indicate that APT is a favorable technique to synthesize pure nanocrystalline CdS0.7Se0.3 thin films having hexagonal crystal structure. An electrochemical impedance spectroscopy analysis confirms the charge transfer resistance. X-ray photoelectron spectroscopy reveals stoichiometry at valance state of Cu-2(S, Se) counter and CdS0.7Se0.3 photoanode. The enhanced photoconversion efficiency achieved was 0.42 % for this counter electrode due to systematic study.</P>