A new process of flat absorber black nickel alloy coating tion from a bath containing nickel, zinc and ammonium was developed on stainless steel by electrodeposi- sulphates; thiocyanate and sodium hypophosphite for sp...A new process of flat absorber black nickel alloy coating tion from a bath containing nickel, zinc and ammonium was developed on stainless steel by electrodeposi- sulphates; thiocyanate and sodium hypophosphite for space applications. Coating process was optimized by investigating the effects of plating parameters, viz concentration of bath constituents, current density, temperature, pH and plating time on the optical properties of the black deposits. Energy dispersive X-ray spectroscopy showed the inclusion of about 6% phosphorous in the coating. The scanning electron microscopy studies revealed the amorphous nature of the coating. The corrosion resistance of the coatings was evaluated by the electrochemical impedance spectroscopy （EIS） and linear polarization （LP） techniques. The results revealed that, phosphorous addition confers better corro- sion resistance in comparison to conventional black nickel coatings. The black nickel coating obtained from hypophosphite bath provides high solar absorptance （αs） and infrared emittance （εIR） of the order of 0.93. Environmental stability to space applications was established by the humidity and thermal cycling tests.展开更多
The bulk of the world’s millet crop is produced by India,Nigeria,Niger,Mali,Burkina Faso,Chad,and China.Finger millet(Eleusine coracana(L.)Gaertn),little millet(Panicum sumatrense Roth ex Roem.&Schult.),foxtail m...The bulk of the world’s millet crop is produced by India,Nigeria,Niger,Mali,Burkina Faso,Chad,and China.Finger millet(Eleusine coracana(L.)Gaertn),little millet(Panicum sumatrense Roth ex Roem.&Schult.),foxtail millet(Setaria italica(L.)P.Beauvois)and proso millet(Panicum miliaceum L.)are most commonly found species among various millet varieties.In India,finger millet occupy the largest area under cultivation among the small millets.Finger millet stands unique among the cereals such as barley,rye and oats with higher nutritional contents and has outstanding properties as a subsistence food crop.It is rich in calcium(0.34%),dietary fiber(18%),phytates(0.48%),protein(6%–13%)minerals(2.5%–3.5%),and phenolics(0.3%–3%).Moreover,it is also a rich source of thiamine,riboflavin,iron,methionine,isoleucine,leucine,phenylalanine and other essential amino acids.The abundance of these phytochemicals enhances the nutraceutical potential of finger millet,making it a powerhouse of health benefiting nutrients.It has distinguished health beneficial properties,such as anti-diabetic(type 2 diabetes mellitus),anti-diarrheal,antiulcer,anti-inflammatory,antitumerogenic(K562 chronic myeloid leukemia),atherosclerogenic effects,antimicrobial and antioxidant properties.展开更多
The corrosion behaviour of the hard anodic coatings prepared by three different methods viz., conventional hard anodizing （C-HA）, pulse hard anodizing （P-HA） and low voltage room temperature pulse hard anodizing ...The corrosion behaviour of the hard anodic coatings prepared by three different methods viz., conventional hard anodizing （C-HA）, pulse hard anodizing （P-HA） and low voltage room temperature pulse hard anodizing （LVP- HA） on AA 6061 was compared using electrochemical impedance spectroscopy （EIS） and linear polarisation. Scanning electron microscope （SEM） was used to study the surface morphology before and after corrosion. EIS data revealed that no significant difference in corrosion resistance was observed among three types. Rp, Icorr and Ecorr were found to be highly stable over the exposure period up to 72 h which confirms the excellent corrosion resistance. The studies indicate that the corrosion resistance of LVP-HA and P-HA, which are processed at lower voltage and at relatively higher temperatures, are comparable to that of C-HA which is processed at sub-zero temperatures and high operating voltages. The corrosion resistance of all coatings was found to be improved after hydrothermal sealing.展开更多
Alumina thin films were deposited on fused quartz and SS304 substrate by pulsed rf magnetron sputtering with both direct and reactive methods. The films were characterised by energy dispersive X-ray spectroscopy, X-ra...Alumina thin films were deposited on fused quartz and SS304 substrate by pulsed rf magnetron sputtering with both direct and reactive methods. The films were characterised by energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, field emission scanning electron microscopy and atomic force microscopy to reveal the microstructure, surface morphology and topography of thin films. Transmittance and reflectance of alumina thin film were evaluated after deposition on the quartz substrate. Transmittance of the quartz remains almost un-altered when alumina was deposited by the reactive sputtering. A marginal decrease of ~4% in the transmittance of quartz was, however, observed after deposition of alumina by direct sputtering. Infrared emittance of the substrate also remains almost constant after deposition of thin alumina film. Further, as-deposited alumina on SS304 obtained by both direct and reactive sputtering process was amorphous in nature. However, after annealing crystalline peaks were observed.展开更多
Titanium powder was rapidly solidified by using shock-wave consolidation technique.The critical parameters were controlled by intrumented detonics and pin-oscillography.The compacted specimens were investigated for cr...Titanium powder was rapidly solidified by using shock-wave consolidation technique.The critical parameters were controlled by intrumented detonics and pin-oscillography.The compacted specimens were investigated for crystal structure and microstructural strengthening by using standard diagnostic techniques.The density of the final product was found to be greater than 96% of the theoretical value.X-ray diffraction pattern reveals intact crystalline structure without the presence of any undesired phases.The particle size reduction indicated by XRD was supported by laser diffraction based particle size analyzer.Results from energy dispersive spectroscopy ruled out the possibility of any segregation within the compacts.Scanning electron microscopy showed crack-free,voids-free,melt-free,fracture-less compacts of titanium with a unidirectional dendrite orientation without any grain-growth.展开更多
A negative unipolar pulsed voltage is applied to study internal electrical parameters of the xenon filled dielectric barrier discharge （DBD） sources. The VUV radiation emitted from these sources is characterized by ...A negative unipolar pulsed voltage is applied to study internal electrical parameters of the xenon filled dielectric barrier discharge （DBD） sources. The VUV radiation emitted from these sources is characterized by means of the photoluminescence intensity of the red phosphor pellet. The red phosphor converts the VUV radiation into visible radiation and the emission spectra include a peak at 619.56 nm. The emission characteristics of the red phosphor are analyzed in terms of the pressure-distance （pd）, rise time and frequency of the pulsed voltage waveform. The emission intensity measured at different operational conditions confirms that the formation and decay of the xenon excimer, Xe2^＊, increase with the increase in reduced electric field, E/N. After exceeding certain limits of E/N, the intensity of Xe2^＊ decreases rapidly.展开更多
Micro-sized copper powder(99.95%;O≤0.3)has been shock-processed with explosives of high detonation velocities of the order of 7.5 km/s to observe the structural and microstructural sub-strengthening.Axisymmetric shoc...Micro-sized copper powder(99.95%;O≤0.3)has been shock-processed with explosives of high detonation velocities of the order of 7.5 km/s to observe the structural and microstructural sub-strengthening.Axisymmetric shock-consolidation technique has been used to obtain conglomerates of granular Cu.The technique involves the cylindrical compaction system wherein the explosive-charge is in direct proximity with the powder whereas the other uses indirect shock pressure with die-plunger geometry.Numeric simulations have been performed on with Eulerian code dynamics.The simulated results show a good agreement with the experimental observation of detonation parameters like detonation velocity,pressure,particle velocity and shock pressure in the reactive media.A pin contactor method has been utilized to calculate the detonation pressure experimentally.Wide angled x-ray diffraction studies reveal that the crystalline structure(FCC)of the shocked specimen matches with the un-shocked specimen.Field emissive scanning electron microscopic examination of the compacted specimens show a good sub-structural strengthening and complement the theoretical considerations.Laser diffraction based particle size analyzer also points towards the reduced particle size of the shock-processed specimen under high detonation velocities.Micro-hardness tests conducted under variable loads of 0.1 kg,0.05 kg and 0.025 kg force with diamond indenter optical micrographs indicate a high order of micro-hardness of the order of 159 Hv.Nitrogen pycnometry used for the density measurement of the compacts shows that a compacted density of the order of 99.3%theoretical mean density has been achieved.展开更多
Surface functionalization of iron oxide nanoparticles(Fe_(2)O_(3) NPs)with antibiotics is a novel approach that opens the door to drug delivery applications.In the present work,we report iron oxide nanoparticles synth...Surface functionalization of iron oxide nanoparticles(Fe_(2)O_(3) NPs)with antibiotics is a novel approach that opens the door to drug delivery applications.In the present work,we report iron oxide nanoparticles synthesized by chemical co-precipitation method.As-synthesized nanoparticles were characterized using field emission scanning electron microscopy(FESEM),energy dispersive X-ray(EDX),X-ray diffraction(XRD),ultraviolet(UV)-visible(Vis)spectroscopy,Fourier transform infrared(FTIR),and vibrating sample magnetometer(VSM).The poly-shaped Fe_(2)O_(3) NPs of size(34±10)nm with hematite(α-Fe_(2)O_(3))phase were synthesized.The antibacterial activity of chloramphenicol and gentamicin and their formulation with encapsulated iron oxide nanoparticles was investigated by the agar well diffusion technique.Drug-encapsulated Fe_(2)O_(3) NPs showed antibacterial activity against Escherichia coli and Staphylococcus aureus strains,possibly in a dose-dependent manner.Significant effectiveness was confirmed by the increase in the single range of inhibition against the tested microorganisms.Furthermore,the effect of iron oxide nanoparticle concentrations ranging from 1 to 9μg/μL on bacterial growth was examined.展开更多
文摘A new process of flat absorber black nickel alloy coating tion from a bath containing nickel, zinc and ammonium was developed on stainless steel by electrodeposi- sulphates; thiocyanate and sodium hypophosphite for space applications. Coating process was optimized by investigating the effects of plating parameters, viz concentration of bath constituents, current density, temperature, pH and plating time on the optical properties of the black deposits. Energy dispersive X-ray spectroscopy showed the inclusion of about 6% phosphorous in the coating. The scanning electron microscopy studies revealed the amorphous nature of the coating. The corrosion resistance of the coatings was evaluated by the electrochemical impedance spectroscopy （EIS） and linear polarization （LP） techniques. The results revealed that, phosphorous addition confers better corro- sion resistance in comparison to conventional black nickel coatings. The black nickel coating obtained from hypophosphite bath provides high solar absorptance （αs） and infrared emittance （εIR） of the order of 0.93. Environmental stability to space applications was established by the humidity and thermal cycling tests.
文摘The bulk of the world’s millet crop is produced by India,Nigeria,Niger,Mali,Burkina Faso,Chad,and China.Finger millet(Eleusine coracana(L.)Gaertn),little millet(Panicum sumatrense Roth ex Roem.&Schult.),foxtail millet(Setaria italica(L.)P.Beauvois)and proso millet(Panicum miliaceum L.)are most commonly found species among various millet varieties.In India,finger millet occupy the largest area under cultivation among the small millets.Finger millet stands unique among the cereals such as barley,rye and oats with higher nutritional contents and has outstanding properties as a subsistence food crop.It is rich in calcium(0.34%),dietary fiber(18%),phytates(0.48%),protein(6%–13%)minerals(2.5%–3.5%),and phenolics(0.3%–3%).Moreover,it is also a rich source of thiamine,riboflavin,iron,methionine,isoleucine,leucine,phenylalanine and other essential amino acids.The abundance of these phytochemicals enhances the nutraceutical potential of finger millet,making it a powerhouse of health benefiting nutrients.It has distinguished health beneficial properties,such as anti-diabetic(type 2 diabetes mellitus),anti-diarrheal,antiulcer,anti-inflammatory,antitumerogenic(K562 chronic myeloid leukemia),atherosclerogenic effects,antimicrobial and antioxidant properties.
文摘The corrosion behaviour of the hard anodic coatings prepared by three different methods viz., conventional hard anodizing （C-HA）, pulse hard anodizing （P-HA） and low voltage room temperature pulse hard anodizing （LVP- HA） on AA 6061 was compared using electrochemical impedance spectroscopy （EIS） and linear polarisation. Scanning electron microscope （SEM） was used to study the surface morphology before and after corrosion. EIS data revealed that no significant difference in corrosion resistance was observed among three types. Rp, Icorr and Ecorr were found to be highly stable over the exposure period up to 72 h which confirms the excellent corrosion resistance. The studies indicate that the corrosion resistance of LVP-HA and P-HA, which are processed at lower voltage and at relatively higher temperatures, are comparable to that of C-HA which is processed at sub-zero temperatures and high operating voltages. The corrosion resistance of all coatings was found to be improved after hydrothermal sealing.
文摘Alumina thin films were deposited on fused quartz and SS304 substrate by pulsed rf magnetron sputtering with both direct and reactive methods. The films were characterised by energy dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, field emission scanning electron microscopy and atomic force microscopy to reveal the microstructure, surface morphology and topography of thin films. Transmittance and reflectance of alumina thin film were evaluated after deposition on the quartz substrate. Transmittance of the quartz remains almost un-altered when alumina was deposited by the reactive sputtering. A marginal decrease of ~4% in the transmittance of quartz was, however, observed after deposition of alumina by direct sputtering. Infrared emittance of the substrate also remains almost constant after deposition of thin alumina film. Further, as-deposited alumina on SS304 obtained by both direct and reactive sputtering process was amorphous in nature. However, after annealing crystalline peaks were observed.
文摘Titanium powder was rapidly solidified by using shock-wave consolidation technique.The critical parameters were controlled by intrumented detonics and pin-oscillography.The compacted specimens were investigated for crystal structure and microstructural strengthening by using standard diagnostic techniques.The density of the final product was found to be greater than 96% of the theoretical value.X-ray diffraction pattern reveals intact crystalline structure without the presence of any undesired phases.The particle size reduction indicated by XRD was supported by laser diffraction based particle size analyzer.Results from energy dispersive spectroscopy ruled out the possibility of any segregation within the compacts.Scanning electron microscopy showed crack-free,voids-free,melt-free,fracture-less compacts of titanium with a unidirectional dendrite orientation without any grain-growth.
文摘A negative unipolar pulsed voltage is applied to study internal electrical parameters of the xenon filled dielectric barrier discharge （DBD） sources. The VUV radiation emitted from these sources is characterized by means of the photoluminescence intensity of the red phosphor pellet. The red phosphor converts the VUV radiation into visible radiation and the emission spectra include a peak at 619.56 nm. The emission characteristics of the red phosphor are analyzed in terms of the pressure-distance （pd）, rise time and frequency of the pulsed voltage waveform. The emission intensity measured at different operational conditions confirms that the formation and decay of the xenon excimer, Xe2^＊, increase with the increase in reduced electric field, E/N. After exceeding certain limits of E/N, the intensity of Xe2^＊ decreases rapidly.
基金Defence Research and Development Organization(DRDO),India,for Grant-in-aid Project No.ERIP/ER/0703665/M/01/1044the University Grants Commission(UGC-New Delhi),India,for providing Research Fellowship No.F.4-1/2006(BSR)/11-08/2008.
文摘Micro-sized copper powder(99.95%;O≤0.3)has been shock-processed with explosives of high detonation velocities of the order of 7.5 km/s to observe the structural and microstructural sub-strengthening.Axisymmetric shock-consolidation technique has been used to obtain conglomerates of granular Cu.The technique involves the cylindrical compaction system wherein the explosive-charge is in direct proximity with the powder whereas the other uses indirect shock pressure with die-plunger geometry.Numeric simulations have been performed on with Eulerian code dynamics.The simulated results show a good agreement with the experimental observation of detonation parameters like detonation velocity,pressure,particle velocity and shock pressure in the reactive media.A pin contactor method has been utilized to calculate the detonation pressure experimentally.Wide angled x-ray diffraction studies reveal that the crystalline structure(FCC)of the shocked specimen matches with the un-shocked specimen.Field emissive scanning electron microscopic examination of the compacted specimens show a good sub-structural strengthening and complement the theoretical considerations.Laser diffraction based particle size analyzer also points towards the reduced particle size of the shock-processed specimen under high detonation velocities.Micro-hardness tests conducted under variable loads of 0.1 kg,0.05 kg and 0.025 kg force with diamond indenter optical micrographs indicate a high order of micro-hardness of the order of 159 Hv.Nitrogen pycnometry used for the density measurement of the compacts shows that a compacted density of the order of 99.3%theoretical mean density has been achieved.
文摘Surface functionalization of iron oxide nanoparticles(Fe_(2)O_(3) NPs)with antibiotics is a novel approach that opens the door to drug delivery applications.In the present work,we report iron oxide nanoparticles synthesized by chemical co-precipitation method.As-synthesized nanoparticles were characterized using field emission scanning electron microscopy(FESEM),energy dispersive X-ray(EDX),X-ray diffraction(XRD),ultraviolet(UV)-visible(Vis)spectroscopy,Fourier transform infrared(FTIR),and vibrating sample magnetometer(VSM).The poly-shaped Fe_(2)O_(3) NPs of size(34±10)nm with hematite(α-Fe_(2)O_(3))phase were synthesized.The antibacterial activity of chloramphenicol and gentamicin and their formulation with encapsulated iron oxide nanoparticles was investigated by the agar well diffusion technique.Drug-encapsulated Fe_(2)O_(3) NPs showed antibacterial activity against Escherichia coli and Staphylococcus aureus strains,possibly in a dose-dependent manner.Significant effectiveness was confirmed by the increase in the single range of inhibition against the tested microorganisms.Furthermore,the effect of iron oxide nanoparticle concentrations ranging from 1 to 9μg/μL on bacterial growth was examined.
