In this present work, we demonstrated a spectral characterization of copper–iron (Cu-Fe) alloy us... more In this present work, we demonstrated a spectral characterization of copper–iron (Cu-Fe) alloy using optical emission spectroscopy. The Cu-Fe alloy plasma was generated on the target sample surface by directing the laser pulse of Q-switched Nd: YAG of the second harmonic (2ω) with a 532 nm optical wavelength. The optical emission spectrum was acquired using five miniature spectrometers that lie within the wavelength range of 200–720 nm. The emission plasma was characterized by validating the local-thermodynamical equilibrium (LTE) as well as optically thin (OT) plasma condition. In addition, the LTE condition was verified using the McWhirter criterion, and the OT condition was validated by comparing theoretically calculated intensity ratios with experimental ones. Plasma parameters, including electron number density as well as plasma temperature, were estimated. In the first stage, the plasma temperature was estimated using the Boltzmann-plot method and the two-line method. The aver...
We have used the Laser Induced Breakdown Spectroscopic (LIBS) technique to qualitatively identify... more We have used the Laser Induced Breakdown Spectroscopic (LIBS) technique to qualitatively identify the naturally existing transparent crystal as a pure quartz (SiO 2) by observing its optical emission spectra using a Q-switched Nd:YAG laser, fundamental wavelength at 1064 nm and second harmonic at 532 nm. The spectra were registered using a set of five miniature spectrometers covering the spectral range from 200 nm to 720 nm. The plasma temperature has been calculated in the range from 8500 K to 10,200 K and the electron densities determined from the Stark broadened spectral lines in the range of 1.0 × 10 17 cm −3 to 6.0 × 10 17 cm −3. We report here the full widths at maximum of the spectral lines associated with the 3p4s 3 P 0,1,2 → 3p 2 3 P 0,1,2 , 1 S 0 , 1 D 2 transitions in Si and four multiplets of singly ionized silicon.
Austenitic stainless steels are of prime importance in many industrial sectors because of their e... more Austenitic stainless steels are of prime importance in many industrial sectors because of their excellent corrosion resistance; however, their poor mechanical and tribological features lead to their reduced applicability. In this regard, low-temperature cathodic cage plasma nitriding (CCPN) can be used to improve surface properties of steels without scarifying the inherent corrosion resistance. In this study, AISI-316 samples are processed in CCPN reactor at a temperature of 400 0 C, for the treatment time of 4 h, at a pressure of 150 Pa and variable pulsed duty cycle (15-75 %). The microstructure and mechanical features are analyzed using X-ray diffraction, scanning electron microscopy, microhardness tester and ball-on-disc wear tester. The anodic polarization test in 3.5 % NaCl is conducted to examine the corrosion properties. The results show that hardness is enhanced up to 1327 HV at low duty cycle, which is considerably higher than base material (278 HV). The wear rate is found to be reduced up to 90 % over base material by processing at low duty cycle. The base material exhibits severe abrasive wear, and the nitrided sample has dominant adhesive wear. The corrosion rate is found to be reduced up to 95 % over base material for the sample nitrided at low duty cycle. This study shows that wear and corrosion resistance in CCPN can be significantly boosted by reducing the pulsed duty cycle.
We have carried out measurements of absolute photoionization cross sections of the 4p excited lev... more We have carried out measurements of absolute photoionization cross sections of the 4p excited levels and oscillator strengths of the 4p-nd Rydberg transitions in potassium using a two-step photo-excitation and ionization technique in conjunction with a thermionic diode ion detector. The measurements were conducted using the linearly polarized laser light and the absolute values of the cross sections from the 4p 2P3/2 and 2P1/2 excited levels have been determined at the ionization threshold as (6.370.9) Mb and (5.470.8) Mb respectively. In addition, photoionization cross sections have been determined at various ionizing wavelengths above the first ionization threshold to explore different energy regions of the continuum. The oscillator strengths for the 4p 2P1/2-nd 2D3/2 and 4p 2P3/2-nd 2D3/2,5/2 Rydberg transitions have been deduced by using the measured cross sections of the 4p 2P1/2 and 2P3/2 levels at the ionization threshold. The new results are in good agreement with the available theoretical and experimental data.
We have carried out measurements of absolute photoionization cross sections of the 4p excited lev... more We have carried out measurements of absolute photoionization cross sections of the 4p excited levels and oscillator strengths of the 4p-nd Rydberg transitions in potassium using a two-step photo-ex-citation and ionization technique in conjunction with a thermionic diode ion detector. The measurements were conducted using the linearly polarized laser light and the absolute values of the cross sections from the 4p 2 P 3/2 and 2 P 1/2 excited levels have been determined at the ionization threshold as (6.37 0.9) Mb and (5.47 0.8) Mb respectively. In addition, photoionization cross sections have been determined at various ionizing wavelengths above the first ionization threshold to explore different energy regions of the continuum. The oscillator strengths for the 4p 2 P 1/2-nd 2 D 3/2 and 4p 2 P 3/2-nd 2 D 3/2,5/2 Rydberg transitions have been deduced by using the measured cross sections of the 4p 2 P 1/2 and 2 P 3/2 levels at the ionization threshold. The new results are in good agreement with the available theoretical and experimental data.
In this present work, we demonstrated a spectral characterization of copper–iron (Cu-Fe) alloy us... more In this present work, we demonstrated a spectral characterization of copper–iron (Cu-Fe) alloy using optical emission spectroscopy. The Cu-Fe alloy plasma was generated on the target sample surface by directing the laser pulse of Q-switched Nd: YAG of the second harmonic (2ω) with a 532 nm optical wavelength. The optical emission spectrum was acquired using five miniature spectrometers that lie within the wavelength range of 200–720 nm. The emission plasma was characterized by validating the local-thermodynamical equilibrium (LTE) as well as optically thin (OT) plasma condition. In addition, the LTE condition was verified using the McWhirter criterion, and the OT condition was validated by comparing theoretically calculated intensity ratios with experimental ones. Plasma parameters, including electron number density as well as plasma temperature, were estimated. In the first stage, the plasma temperature was estimated using the Boltzmann-plot method and the two-line method. The aver...
We have used the Laser Induced Breakdown Spectroscopic (LIBS) technique to qualitatively identify... more We have used the Laser Induced Breakdown Spectroscopic (LIBS) technique to qualitatively identify the naturally existing transparent crystal as a pure quartz (SiO 2) by observing its optical emission spectra using a Q-switched Nd:YAG laser, fundamental wavelength at 1064 nm and second harmonic at 532 nm. The spectra were registered using a set of five miniature spectrometers covering the spectral range from 200 nm to 720 nm. The plasma temperature has been calculated in the range from 8500 K to 10,200 K and the electron densities determined from the Stark broadened spectral lines in the range of 1.0 × 10 17 cm −3 to 6.0 × 10 17 cm −3. We report here the full widths at maximum of the spectral lines associated with the 3p4s 3 P 0,1,2 → 3p 2 3 P 0,1,2 , 1 S 0 , 1 D 2 transitions in Si and four multiplets of singly ionized silicon.
Austenitic stainless steels are of prime importance in many industrial sectors because of their e... more Austenitic stainless steels are of prime importance in many industrial sectors because of their excellent corrosion resistance; however, their poor mechanical and tribological features lead to their reduced applicability. In this regard, low-temperature cathodic cage plasma nitriding (CCPN) can be used to improve surface properties of steels without scarifying the inherent corrosion resistance. In this study, AISI-316 samples are processed in CCPN reactor at a temperature of 400 0 C, for the treatment time of 4 h, at a pressure of 150 Pa and variable pulsed duty cycle (15-75 %). The microstructure and mechanical features are analyzed using X-ray diffraction, scanning electron microscopy, microhardness tester and ball-on-disc wear tester. The anodic polarization test in 3.5 % NaCl is conducted to examine the corrosion properties. The results show that hardness is enhanced up to 1327 HV at low duty cycle, which is considerably higher than base material (278 HV). The wear rate is found to be reduced up to 90 % over base material by processing at low duty cycle. The base material exhibits severe abrasive wear, and the nitrided sample has dominant adhesive wear. The corrosion rate is found to be reduced up to 95 % over base material for the sample nitrided at low duty cycle. This study shows that wear and corrosion resistance in CCPN can be significantly boosted by reducing the pulsed duty cycle.
We have carried out measurements of absolute photoionization cross sections of the 4p excited lev... more We have carried out measurements of absolute photoionization cross sections of the 4p excited levels and oscillator strengths of the 4p-nd Rydberg transitions in potassium using a two-step photo-excitation and ionization technique in conjunction with a thermionic diode ion detector. The measurements were conducted using the linearly polarized laser light and the absolute values of the cross sections from the 4p 2P3/2 and 2P1/2 excited levels have been determined at the ionization threshold as (6.370.9) Mb and (5.470.8) Mb respectively. In addition, photoionization cross sections have been determined at various ionizing wavelengths above the first ionization threshold to explore different energy regions of the continuum. The oscillator strengths for the 4p 2P1/2-nd 2D3/2 and 4p 2P3/2-nd 2D3/2,5/2 Rydberg transitions have been deduced by using the measured cross sections of the 4p 2P1/2 and 2P3/2 levels at the ionization threshold. The new results are in good agreement with the available theoretical and experimental data.
We have carried out measurements of absolute photoionization cross sections of the 4p excited lev... more We have carried out measurements of absolute photoionization cross sections of the 4p excited levels and oscillator strengths of the 4p-nd Rydberg transitions in potassium using a two-step photo-ex-citation and ionization technique in conjunction with a thermionic diode ion detector. The measurements were conducted using the linearly polarized laser light and the absolute values of the cross sections from the 4p 2 P 3/2 and 2 P 1/2 excited levels have been determined at the ionization threshold as (6.37 0.9) Mb and (5.47 0.8) Mb respectively. In addition, photoionization cross sections have been determined at various ionizing wavelengths above the first ionization threshold to explore different energy regions of the continuum. The oscillator strengths for the 4p 2 P 1/2-nd 2 D 3/2 and 4p 2 P 3/2-nd 2 D 3/2,5/2 Rydberg transitions have been deduced by using the measured cross sections of the 4p 2 P 1/2 and 2 P 3/2 levels at the ionization threshold. The new results are in good agreement with the available theoretical and experimental data.
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Papers by Javed Iqbal
and oscillator strengths of the 4p-nd Rydberg transitions in potassium using a two-step photo-excitation
and ionization technique in conjunction with a thermionic diode ion detector. The measurements
were conducted using the linearly polarized laser light and the absolute values of the cross sections
from the 4p 2P3/2 and 2P1/2 excited levels have been determined at the ionization threshold as
(6.370.9) Mb and (5.470.8) Mb respectively. In addition, photoionization cross sections have been
determined at various ionizing wavelengths above the first ionization threshold to explore different
energy regions of the continuum. The oscillator strengths for the 4p 2P1/2-nd 2D3/2 and 4p 2P3/2-nd
2D3/2,5/2 Rydberg transitions have been deduced by using the measured cross sections of the 4p 2P1/2 and
2P3/2 levels at the ionization threshold. The new results are in good agreement with the available theoretical
and experimental data.
and oscillator strengths of the 4p-nd Rydberg transitions in potassium using a two-step photo-excitation
and ionization technique in conjunction with a thermionic diode ion detector. The measurements
were conducted using the linearly polarized laser light and the absolute values of the cross sections
from the 4p 2P3/2 and 2P1/2 excited levels have been determined at the ionization threshold as
(6.370.9) Mb and (5.470.8) Mb respectively. In addition, photoionization cross sections have been
determined at various ionizing wavelengths above the first ionization threshold to explore different
energy regions of the continuum. The oscillator strengths for the 4p 2P1/2-nd 2D3/2 and 4p 2P3/2-nd
2D3/2,5/2 Rydberg transitions have been deduced by using the measured cross sections of the 4p 2P1/2 and
2P3/2 levels at the ionization threshold. The new results are in good agreement with the available theoretical
and experimental data.