For the purpose of improving the strength of this dissimilarjoint, the present study was carried out to investigate the improvement in intermetallic layer by using a third material foil between the laying edges of the...For the purpose of improving the strength of this dissimilarjoint, the present study was carried out to investigate the improvement in intermetallic layer by using a third material foil between the laying edges of the friction stir welded and hybrid welded AI6061-T6/AZ31 alloy plates. The difference in microstructural and mechanical characteristics of friction stir welded and hybrid welded AI6061-TO/AZ31 joint was compared. Hybrid butt- welding of aluminum alloy plate to a magnesium alloy plate was successfully achieved with Ni foil as filler material, while defect-free laser-friction stir welding （FSW） hybrid welding was achieved by using a laser power of 2 kW. Transverse tensile strength of the joint reached about 66% of the Mg base metal tensile strength in the case of hybrid welding with Ni foil and showed higher value than that of the friction stir welded joint with and without the third material foil. This may be due to the presence of less brittle Ni-based intermetallic phases instead of Al12Mg17.展开更多
The present study focuses on the synthesis and characterization of lanthanum(La^(3+))-doped calcium nanoferrites(CaLa_(x)Fe_(2-x)O_(4):x=0.025,0.050,0.075 and 0.100)using the sonochemical method.Various techniques wer...The present study focuses on the synthesis and characterization of lanthanum(La^(3+))-doped calcium nanoferrites(CaLa_(x)Fe_(2-x)O_(4):x=0.025,0.050,0.075 and 0.100)using the sonochemical method.Various techniques were employed to analyze the effect of La^(3+)infusion,Raman spectroscopy confirms the presence of active A_(1g),T_(2g)and E_g modes in the CaLa_(x)Fe_(2-x)O_(4)nanoferrite,indicating the formation of an active ferrite system.The introduction of La^(3+)doping results in a significant increase in the band gap energy,rendering the nanoferrites insulating(3.23-3,57 eV).At higher frequencies,the impedance studies reveal minimal losses and better AC conductivity,pointing to improved dielectric characteristics.At higher frequencies,the Q-factor of La-doped calcium nanoferrites shows lower electromagnetic losses.The M-H curve exhibits ferromagnetic behavior,with La^(3+)-doped calcium nano ferrites displaying a saturation magnetization ranging from 12.72 to 18.10 emu/g.The incorporation of La^(3+)also induces enhanced electrical polarization,leading to notable dielectric loss and increased absorption of electromagnetic waves.Consequently,these CaLa_(x)Fe_(2-x)O_(4)nanoferrites demonstrate potential as effective microwave absorbers across a wide frequency range,with significant shielding absorption observed at 8.8-9.1 GHz.展开更多
Electrical Discharge Machining (EDM) is considered as the much traditional, adaptableand unconventional machining process that is proficient in generating complicated structures. Further, it is self-sufficient over t...Electrical Discharge Machining (EDM) is considered as the much traditional, adaptableand unconventional machining process that is proficient in generating complicated structures. Further, it is self-sufficient over the mechanical properties of workpiece materialsonly if it is conductive. The viability of the EDM process regarding the application typesmight get considerably improved with the constant enhancement in the personificationof numerical control and the metal removal efficacy. This survey intends to make a reviewof 65 papers related to the optimization and modeling of EDM process machining. Theanalysis is thus made with regards to the following factors like Al alloy composite in DieShrinking EDM, Optimization and Al metal matrix composites. Particularly, the hybridoptimization models in various papers are analyzed concerning their logic. Further, thealgorithmic and parametric analysis is also made with the contributed papers. Finally,the research gaps and challenges in this EDM processing are discussed, which wouldpave the way for efficient research works in this area.展开更多
In this study,the biosorption of Malachite green(MG)onto Turbinaria conoides,brown marine algae,was studied with respect to initial pH,temperature,initial dye concentration,and sorbent dosage.The optimum initial pH an...In this study,the biosorption of Malachite green(MG)onto Turbinaria conoides,brown marine algae,was studied with respect to initial pH,temperature,initial dye concentration,and sorbent dosage.The optimum initial pH and temperature values for MG removal were found to be 8.0 and 30℃,respectively.Sorbent dosage was found to strongly influence the removal of MG.Equilibrium studies were carried out to test the validity of the Langmuir(q_(max)=66.6 mg/g and b=0.526 mL mol/L)and the Freundlich(n=1.826 and K=3.751 mg/g)isotherms.The kinetic studies indicated the validity of the pseudo first-order and second-order equation.展开更多
We investigate the transition of a radiatively inefficient phase of a viscous two temperature accreting flow to a cooling dominated phase and vice versa around black holes. Based on a global sub-Keplerian accretion di...We investigate the transition of a radiatively inefficient phase of a viscous two temperature accreting flow to a cooling dominated phase and vice versa around black holes. Based on a global sub-Keplerian accretion disk model in steady state, including explicit cooling processes self-consistently, we show that general advective accretion flow passes through various phases during its infall towards a black hole. Bremsstrahlung, syn- chrotron and inverse Comptonization of soft photons are considered as possible cooling mechanisms. Hence the flow governs a much lower electron temperature ～10^8 - 10^9.5 K compared to the hot protons of temperature ～10^10.2 - 10^11.8 K in the range of the accretion rate in Eddington units 0.01≤M≤ 100. Therefore, the solutions may potentially explain the hard X-rays and the γ-rays emitted from AGNs and X-ray binaries. We finally compare the solutions for two different regimes of viscosity and conclude that a weakly viscous flow is expected to be cooling dominated compared to its highly viscous counterpart which is radiatively inefficient. The flow is successfully able to reproduce the observed luminosities of the under-fed AGNs and quasars （e.g. Sgr A＊）, ultra-luminous X-ray sources （e.g. SS433）, as well as the highly luminous AGNs and ultra-luminous quasars （e.g. PKS 0743-67） at different combinations of the mass accretion rate and ratio of specific heats.展开更多
In this paper, we compute Atom-bond connectivity index, Fourth atom-bond connectivity index, Sum connectivity index, Randic connectivity index, Geometric-arithmetic connectivity index and Fifth geometric-arithmetic co...In this paper, we compute Atom-bond connectivity index, Fourth atom-bond connectivity index, Sum connectivity index, Randic connectivity index, Geometric-arithmetic connectivity index and Fifth geometric-arithmetic connectivity index of Dutch windmill graph.展开更多
Randićenergy was first defined in the paper [1]. Using minimum covering set, we have introduced the minimum covering Randićenergy RE<sub>C</sub> (G) of a graph G in this paper. This p...Randićenergy was first defined in the paper [1]. Using minimum covering set, we have introduced the minimum covering Randićenergy RE<sub>C</sub> (G) of a graph G in this paper. This paper contains computation of minimum covering Randićenergies for some standard graphs like star graph, complete graph, thorn graph of complete graph, crown graph, complete bipartite graph, cocktail graph and friendship graphs. At the end of this paper, upper and lower bounds for minimum covering Randićenergy are also presented.展开更多
Let G = (V;E) be a simple connected graph. The Wiener index is the sum of distances between all pairs of vertices of a connected graph. The Schultz topological index is equal to and the Modified Schultz topological in...Let G = (V;E) be a simple connected graph. The Wiener index is the sum of distances between all pairs of vertices of a connected graph. The Schultz topological index is equal to and the Modified Schultz topological index is . In this paper, the Schultz, Modified Schultz polynomials and their topological indices of Jahangir graphs J<sub>2,m</sub> for all integer number m ≥ 3 are calculated.展开更多
A topological index is a numerical value associated with chemical constitution for correlation of chemical structure with various physical properties, chemical reactivity or biological activity. In this paper, we comp...A topological index is a numerical value associated with chemical constitution for correlation of chemical structure with various physical properties, chemical reactivity or biological activity. In this paper, we computed the Omega and Cluj-Ilumenau indices of a very famous hydrocarbon named as Polycyclic Aromatic Hydrocarbons PAH<sub>k</sub> for all integer number k.展开更多
In theoretical chemistry, the researchers use graph models to express the structure of molecular, and the Zagreb indices and multiplicative Zagreb indices defined on molecular graph G are applied to measure the chemic...In theoretical chemistry, the researchers use graph models to express the structure of molecular, and the Zagreb indices and multiplicative Zagreb indices defined on molecular graph G are applied to measure the chemical characteristics of compounds and drugs. In this paper, we present the exact expressions of multiplicative Zagreb indices for certain important chemical structures like nanotube, nanostar and polyomino chain.展开更多
Let G = (V,E) be a graph, where V(G) is a non-empty set of vertices and E(G) is a set of edges, e = uv∈E(G), d(u) is degree of vertex u. Then the first Zagreb polynomial and the first Zagreb index Zg<sub>1</...Let G = (V,E) be a graph, where V(G) is a non-empty set of vertices and E(G) is a set of edges, e = uv∈E(G), d(u) is degree of vertex u. Then the first Zagreb polynomial and the first Zagreb index Zg<sub>1</sub>(G,x) and Zg<sub>1</sub>(G) of the graph G are defined as Σ<sub>uv∈E(G)</sub>x<sup>(d<sub>u</sub>+d<sub>v</sub>)</sup> and Σ<sub>e=uv∈E(G)</sub>(d<sub>u</sub>+d<sub>v</sub>) respectively. Recently Ghorbani and Hosseinzadeh introduced the first Eccentric Zagreb index as Zg<sub>1</sub>*</sup>=Σ<sub>uv∈E(G)</sub>(ecc(v)+ecc(u)), that ecc(u) is the largest distance between u and any other vertex v of G. In this paper, we compute this new index (the first Eccentric Zagreb index or third Zagreb index) of an infinite family of linear Polycene parallelogram of benzenoid.展开更多
文摘For the purpose of improving the strength of this dissimilarjoint, the present study was carried out to investigate the improvement in intermetallic layer by using a third material foil between the laying edges of the friction stir welded and hybrid welded AI6061-T6/AZ31 alloy plates. The difference in microstructural and mechanical characteristics of friction stir welded and hybrid welded AI6061-TO/AZ31 joint was compared. Hybrid butt- welding of aluminum alloy plate to a magnesium alloy plate was successfully achieved with Ni foil as filler material, while defect-free laser-friction stir welding （FSW） hybrid welding was achieved by using a laser power of 2 kW. Transverse tensile strength of the joint reached about 66% of the Mg base metal tensile strength in the case of hybrid welding with Ni foil and showed higher value than that of the friction stir welded joint with and without the third material foil. This may be due to the presence of less brittle Ni-based intermetallic phases instead of Al12Mg17.
基金Project supported by the Strategic Academic Leadership Program of the Southern Federal University(Priority 2030)。
文摘The present study focuses on the synthesis and characterization of lanthanum(La^(3+))-doped calcium nanoferrites(CaLa_(x)Fe_(2-x)O_(4):x=0.025,0.050,0.075 and 0.100)using the sonochemical method.Various techniques were employed to analyze the effect of La^(3+)infusion,Raman spectroscopy confirms the presence of active A_(1g),T_(2g)and E_g modes in the CaLa_(x)Fe_(2-x)O_(4)nanoferrite,indicating the formation of an active ferrite system.The introduction of La^(3+)doping results in a significant increase in the band gap energy,rendering the nanoferrites insulating(3.23-3,57 eV).At higher frequencies,the impedance studies reveal minimal losses and better AC conductivity,pointing to improved dielectric characteristics.At higher frequencies,the Q-factor of La-doped calcium nanoferrites shows lower electromagnetic losses.The M-H curve exhibits ferromagnetic behavior,with La^(3+)-doped calcium nano ferrites displaying a saturation magnetization ranging from 12.72 to 18.10 emu/g.The incorporation of La^(3+)also induces enhanced electrical polarization,leading to notable dielectric loss and increased absorption of electromagnetic waves.Consequently,these CaLa_(x)Fe_(2-x)O_(4)nanoferrites demonstrate potential as effective microwave absorbers across a wide frequency range,with significant shielding absorption observed at 8.8-9.1 GHz.
文摘Electrical Discharge Machining (EDM) is considered as the much traditional, adaptableand unconventional machining process that is proficient in generating complicated structures. Further, it is self-sufficient over the mechanical properties of workpiece materialsonly if it is conductive. The viability of the EDM process regarding the application typesmight get considerably improved with the constant enhancement in the personificationof numerical control and the metal removal efficacy. This survey intends to make a reviewof 65 papers related to the optimization and modeling of EDM process machining. Theanalysis is thus made with regards to the following factors like Al alloy composite in DieShrinking EDM, Optimization and Al metal matrix composites. Particularly, the hybridoptimization models in various papers are analyzed concerning their logic. Further, thealgorithmic and parametric analysis is also made with the contributed papers. Finally,the research gaps and challenges in this EDM processing are discussed, which wouldpave the way for efficient research works in this area.
文摘In this study,the biosorption of Malachite green(MG)onto Turbinaria conoides,brown marine algae,was studied with respect to initial pH,temperature,initial dye concentration,and sorbent dosage.The optimum initial pH and temperature values for MG removal were found to be 8.0 and 30℃,respectively.Sorbent dosage was found to strongly influence the removal of MG.Equilibrium studies were carried out to test the validity of the Langmuir(q_(max)=66.6 mg/g and b=0.526 mL mol/L)and the Freundlich(n=1.826 and K=3.751 mg/g)isotherms.The kinetic studies indicated the validity of the pseudo first-order and second-order equation.
基金supported by a project,Grant No.SR/S2HEP12/2007,funded by DST,India
文摘We investigate the transition of a radiatively inefficient phase of a viscous two temperature accreting flow to a cooling dominated phase and vice versa around black holes. Based on a global sub-Keplerian accretion disk model in steady state, including explicit cooling processes self-consistently, we show that general advective accretion flow passes through various phases during its infall towards a black hole. Bremsstrahlung, syn- chrotron and inverse Comptonization of soft photons are considered as possible cooling mechanisms. Hence the flow governs a much lower electron temperature ～10^8 - 10^9.5 K compared to the hot protons of temperature ～10^10.2 - 10^11.8 K in the range of the accretion rate in Eddington units 0.01≤M≤ 100. Therefore, the solutions may potentially explain the hard X-rays and the γ-rays emitted from AGNs and X-ray binaries. We finally compare the solutions for two different regimes of viscosity and conclude that a weakly viscous flow is expected to be cooling dominated compared to its highly viscous counterpart which is radiatively inefficient. The flow is successfully able to reproduce the observed luminosities of the under-fed AGNs and quasars （e.g. Sgr A＊）, ultra-luminous X-ray sources （e.g. SS433）, as well as the highly luminous AGNs and ultra-luminous quasars （e.g. PKS 0743-67） at different combinations of the mass accretion rate and ratio of specific heats.
文摘In this paper, we compute Atom-bond connectivity index, Fourth atom-bond connectivity index, Sum connectivity index, Randic connectivity index, Geometric-arithmetic connectivity index and Fifth geometric-arithmetic connectivity index of Dutch windmill graph.
文摘Randićenergy was first defined in the paper [1]. Using minimum covering set, we have introduced the minimum covering Randićenergy RE<sub>C</sub> (G) of a graph G in this paper. This paper contains computation of minimum covering Randićenergies for some standard graphs like star graph, complete graph, thorn graph of complete graph, crown graph, complete bipartite graph, cocktail graph and friendship graphs. At the end of this paper, upper and lower bounds for minimum covering Randićenergy are also presented.
文摘Let G = (V;E) be a simple connected graph. The Wiener index is the sum of distances between all pairs of vertices of a connected graph. The Schultz topological index is equal to and the Modified Schultz topological index is . In this paper, the Schultz, Modified Schultz polynomials and their topological indices of Jahangir graphs J<sub>2,m</sub> for all integer number m ≥ 3 are calculated.
文摘A topological index is a numerical value associated with chemical constitution for correlation of chemical structure with various physical properties, chemical reactivity or biological activity. In this paper, we computed the Omega and Cluj-Ilumenau indices of a very famous hydrocarbon named as Polycyclic Aromatic Hydrocarbons PAH<sub>k</sub> for all integer number k.
文摘In theoretical chemistry, the researchers use graph models to express the structure of molecular, and the Zagreb indices and multiplicative Zagreb indices defined on molecular graph G are applied to measure the chemical characteristics of compounds and drugs. In this paper, we present the exact expressions of multiplicative Zagreb indices for certain important chemical structures like nanotube, nanostar and polyomino chain.
文摘Let G = (V,E) be a graph, where V(G) is a non-empty set of vertices and E(G) is a set of edges, e = uv∈E(G), d(u) is degree of vertex u. Then the first Zagreb polynomial and the first Zagreb index Zg<sub>1</sub>(G,x) and Zg<sub>1</sub>(G) of the graph G are defined as Σ<sub>uv∈E(G)</sub>x<sup>(d<sub>u</sub>+d<sub>v</sub>)</sup> and Σ<sub>e=uv∈E(G)</sub>(d<sub>u</sub>+d<sub>v</sub>) respectively. Recently Ghorbani and Hosseinzadeh introduced the first Eccentric Zagreb index as Zg<sub>1</sub>*</sup>=Σ<sub>uv∈E(G)</sub>(ecc(v)+ecc(u)), that ecc(u) is the largest distance between u and any other vertex v of G. In this paper, we compute this new index (the first Eccentric Zagreb index or third Zagreb index) of an infinite family of linear Polycene parallelogram of benzenoid.
