Oštećenja u aluminiju proizvedena zračenjem iz CO2 i Nd:YAG lasera

The change in the electrical properties of pure aluminium (Al 99.999%) after exposure to CO2 (energy = 2.5 J/pulse, wavelength = 10.6 µm, pulse duration = 200 nsec) and Nd:YAG (energy = 10 mJ/pulse, wavelength = 1.06 µm and pulse duration = 12 nsec) laser radiation is investigated. The samples were exposed to laser radiations for different numbers of pulses. The change in electrical characteristics of Al is studied under different ambient conditions, after irradiating the samples in air, vacuum and hydrogen at different pressures. After exposure, the electrical conductivity of Al is measured by the four probe method. The electrical conductivity decreases with increasing number of pulses. The damage in air and in hydrogen is more pronounced than in vacuum which can be attributed to collisionnal sputtering of Al by plasma ions of air molecules and hydrogen, respectively. The change in the conductivity in hydrogen is pressure-dependent. Some theoretical considerations are also made, e.g. the phonon speed in Al during the photon interaction, minimal melting and evaporation energy per volume, damage threshold energy, penetration depth, the mass of heated volume and average temperature rise at the Al surface during laser irradiation.Proučavamo promjene električnih svojstava čistog aluminija (Al 99.999%) nakon obasjavanja CO2 (energija = 2.5 J/puls, valna duljina = 10.6 µm, trajanje pulsa = 200 nsec) i Nd:YAG (energija = 10 mJ/puls, valna duljina = 1.06 µm, trajanje pulsa = 12 nsec) laserima. Uzorci su izloženi različitim brojevima pulseva. Proučavali smo promjene električne vodljivosti Al s uzorcima u zraku, vakuumu i u vodiku. Nakon obasjavanja mjerili smo električnu vodljivost metodom četiriju spojišta. Električna se vodljivost smanjuje nakon povećanog broja pulseva. Oštećenja u zraku i vodiku veća su nego u vakuumu, što se pripisuje sudarnom rasprašivanju Al ionima molekula zraka odnosno vodika u plazmi. Promjena vodljivosti uzoraka obasjanih u vodiku ovisna je o tlaku. Razmotrili smo neke teorijske rezultate, npr. fononsku brzinu u Al tijekom obasjavanja, minimalnu energiju taljenja i isparavanja po jedinici volumena, energijski prag oštećenja, dubinu prodiranja, masu zagrijanog volumena i prosječno povećanje temperature površine Al tijekom obasjavanja

Oštećenja u aluminiju proizvedena zračenjem iz CO2 i Nd:YAG lasera

The change in the electrical properties of pure aluminium (Al 99.999%) after exposure to CO2 (energy = 2.5 J/pulse, wavelength = 10.6 µm, pulse duration = 200 nsec) and Nd:YAG (energy = 10 mJ/pulse, wavelength = 1.06 µm and pulse duration = 12 nsec) laser radiation is investigated. The samples were exposed to laser radiations for different numbers of pulses. The change in electrical characteristics of Al is studied under different ambient conditions, after irradiating the samples in air, vacuum and hydrogen at different pressures. After exposure, the electrical conductivity of Al is measured by the four probe method. The electrical conductivity decreases with increasing number of pulses. The damage in air and in hydrogen is more pronounced than in vacuum which can be attributed to collisionnal sputtering of Al by plasma ions of air molecules and hydrogen, respectively. The change in the conductivity in hydrogen is pressure-dependent. Some theoretical considerations are also made, e.g. the phonon speed in Al during the photon interaction, minimal melting and evaporation energy per volume, damage threshold energy, penetration depth, the mass of heated volume and average temperature rise at the Al surface during laser irradiation.Proučavamo promjene električnih svojstava čistog aluminija (Al 99.999%) nakon obasjavanja CO2 (energija = 2.5 J/puls, valna duljina = 10.6 µm, trajanje pulsa = 200 nsec) i Nd:YAG (energija = 10 mJ/puls, valna duljina = 1.06 µm, trajanje pulsa = 12 nsec) laserima. Uzorci su izloženi različitim brojevima pulseva. Proučavali smo promjene električne vodljivosti Al s uzorcima u zraku, vakuumu i u vodiku. Nakon obasjavanja mjerili smo električnu vodljivost metodom četiriju spojišta. Električna se vodljivost smanjuje nakon povećanog broja pulseva. Oštećenja u zraku i vodiku veća su nego u vakuumu, što se pripisuje sudarnom rasprašivanju Al ionima molekula zraka odnosno vodika u plazmi. Promjena vodljivosti uzoraka obasjanih u vodiku ovisna je o tlaku. Razmotrili smo neke teorijske rezultate, npr. fononsku brzinu u Al tijekom obasjavanja, minimalnu energiju taljenja i isparavanja po jedinici volumena, energijski prag oštećenja, dubinu prodiranja, masu zagrijanog volumena i prosječno povećanje temperature površine Al tijekom obasjavanja

Clinical efficacy of certain Unani herbs in knee osteoarthritis: A pretest and post-test evaluation study

Objectives: This study was conducted to evaluate the efficacy of preparations of certain Unani herbs on Lequesne Algo-Functional Index of knee osteoarthritis (OA). Materials and Methods: A prospective, pre- and post test evaluation study was conducted on 20 diagnosed patients of OA recruited from the Nizamia General Hospital, Hyderabad. Internally, a combination (formula) of Unani herbs was administered, which was as follows: 3.5 g powder of Asarun (2 g), Tukhme karafs (2 g), and Filfil daraz (3 g) was administered internally twice daily. Externally, the concoction of Gule baboona (20 g) and Gule tesu (40 g) made in 1 l water was poured over the affected knee, daily once for 40 days. The primary outcome was to assess the efficacy of Unani test drugs with the modified Lequesne Algo-Functional Index for knee OA. Results: The mean percentage reduction of Lequesne Algo-Functional Index score was 71.09%. The mean and standard deviation was 10.55 (1.70) and 3.05 (2.30) before treatment and after treatment, respectively. The pre- and post test evaluation showed reduction in Lequesne Algo-Functional Index score (P < 0.0001). Conclusion: In this study, the Unani treatment module was found to be effective in reducing the severity of disease in patients with osteoarthritis of knees

Sn doped ZnO Thin Films Prepared by Pulsed Laser Deposition for Photovoltaic Applications

The objective of the present research work is to prepare various compositions of Sn doped ZnO thin films on a single crystal silicon (1 0 0) substrate via pulsed laser deposition technique, for investigation of valuable structural and optical properties. For this purpose, targets of pure and Sn-ZnO were prepared in the form of compressed, sintered and densified pellets by solid state reaction method. A KrF excimer laser (λ=248 nm, τ=20 ns, El = 20 mJ and Φl=1 J/cm2) was employed to deposit various thin films on silicon substrate. Post deposition annealing of all the Sn-ZnO thin films was carried out at 300 ˚C, and their structural and optical properties were investigated by X-ray diffraction (XRD) and Spectroscopic Ellipsometry (SE), respectively. It was observed from XRD results that ZnO (0 0 2) and SnO2 (2 1 0) were preferred planes orientations for all the Sn-ZnO thin films. The presence of SnO2 peak showed that SnO2 was epitaxialy included in ZnO matrix. The crystallite size of all the thin films was measured with the help of Scherrer‘s formula and it was decreased with the increase of Sn concentration in ZnO. Spectroscopic ellipsometry analysis showed that the values of refractive index (n) and extinction coefficient (k) were increased and optical band gap of the thin films was reduced with addition of Sn contents in ZnO thin films. The modification in band gap energy could be attributed to the crystallites size of the thin film; the decrease in crystallite size decreased the band gap energy, which makes the thin films valuable for variety of photovoltaic applications

Investigation of blood flow characteristics saturated by graphene/CuO hybrid nanoparticles under quadratic radiation using VIM: study for expanding/contracting channel

Abstract The importance of heat transfer in nanoliquids cannot avoided because it playing crucial role in the applied research fields. The potential area of applications included but restricted to applied thermal, biomedical, mechanical and chemical engineering. Therefore, it is the need of time to introduce new efficient way to enhance the heat transport rate in common fluids. The major aim of this research is to develop a new heat transport BHNF (Biohybrid Nanofluid Model) model in a channel having expanding/contracting walls up to Newtonian regimes of blood. The two sort of nanomaterials (Graphene + CuO) along with blood as base solvent are taken for the formation of working fluid. After that, the model analyzed via VIM (Variational Iteration Method) to examine the influence of involved physical parameters on the behavior of bionanofluids. The model results revealed that the bionanofluids velocity rises towards the lower and upper channel end when the expanding/contracting of the walls in the range of 0.1–1.6 (expanding case) and $$- \, 0.1$$ - 0.1 to $$1.6$$ 1.6 (contraction case). The working fluid attained high velocity in the neighboring of center portion of the channel. By increasing the walls permeability ( $${A}_{1}=\text{0.1,0.2,0.3,0.4}$$ A 1 = 0.1,0.2,0.3,0.4 ), the fluid movement can be reduced and optimum decrement observed about $$\eta =0.0$$ η = 0.0 . Further, inclusion of thermal radiation (Rd) and temperature coefficient ( $${\theta }_{r}$$ θ r ) observed good to enhance thermal mechanism in both hybrid and simple bionanofluids. The present ranges of Rd and $${\theta }_{r}$$ θ r considered from $$0.1$$ 0.1 to $$0.9$$ 0.9 and $$0.1$$ 0.1 to $$1.4$$ 1.4 , respectively. Thermal boundary layer reduced in the case of simple bionanoliquid keeping $${P}_{r}=21.0$$ P r = 21.0