Motivated by the early works on bidirectional interaction and the breakthrough to estimate seismic response to bidirectional shaking via unidirectional analysis,it is essential to answer the question:When is the inter...Motivated by the early works on bidirectional interaction and the breakthrough to estimate seismic response to bidirectional shaking via unidirectional analysis,it is essential to answer the question:When is the interaction effect significant?Early works concluded that the effect of interaction is pronounced for stiff systems;consequently,the straightforward method for estimating seismic response to bidirectional excitation by using unidirectional analyses is verified primarily for short period systems.Hence,it is essential to identify the domain of significance for bidirectional interaction before adopting this simple methodology in design.Several parametrically defined systems with elastoplastic and degrading hysteresis models are studied under near-fault motions,assuming strength-independent and strength-dependent stiffness.The force-based and displacement-based analyses,conducted in parallel,reveal that the interaction effect is considerable for stiff systems,especially with degrading characteristics in a relatively low inelasticity range.However,the bidirectional effect may be significant even for highly flexible systems,especially for residual deformation,which in earlier works was shrouded.The range of significance depends on the hysteresis model,system parameters,and response indices.Regression analysis is carried out with the results of the case studies,and the derived regression models may be used for a preliminary assessment of the impact of interaction in advance.展开更多
In this paper,we develop a quantum communication protocol for the simultaneous preparation of a two-qubit and a three-qubit state at the positions of two different parties situated spatially apart.For one party,Alice,...In this paper,we develop a quantum communication protocol for the simultaneous preparation of a two-qubit and a three-qubit state at the positions of two different parties situated spatially apart.For one party,Alice,it is a remote state preparation of a known two-qubit state while for the other party,Bob,it is a joint remote state preparation with the help of a third party,Eve.The protocol is executed in a hybrid form bi-directionally in the presence of two controllers,Charlie and David.There is a hierarchy in the process through different levels of control under which the actions by Alice and Bob are performed.There is a need for a ten-qubit entangled channel connecting the five parties.The generation of this channel through a circuit is discussed.The protocol is executed on the IBM Quantum platform.We also study the effect of noise on our protocol.Here,amplitude-damping,bit-flip and phase-flip noisy environments are considered and the corresponding variations of fidelity are theoretically and numerically analyzed.展开更多
With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2...With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its infancy.Thus,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers mobility.The atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device operations.We also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various applications.Presently,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk semiconductors.We also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional junctions.Finally,we talked about the problems and potential for the future.展开更多
MgZn_(2)-type(Hf,Ta)Fe_(2),known for its negative thermal expansion during magnetic transition,is a key component in the production of zero thermal expansion composites.This paper presents a basic approach for designi...MgZn_(2)-type(Hf,Ta)Fe_(2),known for its negative thermal expansion during magnetic transition,is a key component in the production of zero thermal expansion composites.This paper presents a basic approach for designing such composites by introducing an additional Laves phase through atomic substitution.Specifically,Co,Ni,A1 and V were chosen to substitute Fe in(Hf,Ta)Fe_(2).The addition of Co or Ni results in the creation of an extra MgCu_(2)(C15)phase in the MgZn_(2)(C14)matrix.The C15phase exhibits positive thermal expansion,which effectively compensates for the negative thermal expansion of the C14 matrix.By adjusting the amount of Co or Ni,zero thermal expansion can be achieved in a given temperature range.Meanwhile,the replacement of Fe by Al or V yields another C14 phase with a higher doping element content relative to the C14 matrix.These two C14 phases possess different magnetic transition temperatures and negative thermal expansion temperature regions.The combination of the two C14 phases results in zero thermal expansion due to the effective thermal expansion compensation between them.Our results serve to identify potential approaches for designing(Hf,Ta)Fe_(2)-based zero thermal expansion composites.展开更多
Novel characteristics of graphene have captured great attention of researchers for energy technology applications.Incorporation of graphene related hybrid and composite materials have demonstrated high performance and...Novel characteristics of graphene have captured great attention of researchers for energy technology applications.Incorporation of graphene related hybrid and composite materials have demonstrated high performance and durability for fuel cell energy conversion devices.This article overviews graphene based materials for fuel cell technology applications such as electrodes additives,bipolar plates and proton conducting electrolyte membrane.The graphene dispersion over electrodes has revealed enhanced exposure of electrochemically active surface area for improved electro-catalytic activity towards fuel oxidation and oxidant reduction reactions.The issue of device stack durability and degraded performance due to corrosion of bipolar plates is discussed by incorporating graphene based materials.In proton exchange membrane devices,graphene as an electrolyte has shown an excellent performance towards high ionic conductivity and power density.The graphene incorporation in fuel cell devices has exhibited commendable performance and has bright future for commercial applications.展开更多
This study performs single point incremental forming(SPIF)on two aluminum alloys(i.e.AA5754 and AA6061),and analyzes their post forming mechanical properties and microstructure evolution.The forming parameters namely ...This study performs single point incremental forming(SPIF)on two aluminum alloys(i.e.AA5754 and AA6061),and analyzes their post forming mechanical properties and microstructure evolution.The forming parameters namely wall angle(35°-55°),feed rate(1-4 m/min),spindle rotational speed(50-1000 r/min),and lubricant(grease and hydraulic oil)are varied to probe detailed processing effects.The pre-and post-SPIF mechanical properties and microstructures are characterized by conducting tensile tests and optical microscopy,respectively.It is shown that an increase in the wall angle,feed rate and rotational speed causes microscopic variations in the alloys such that the grains of AA5754 and the second phase particles of AA6061 elongate.As a result,the ultimate tensile strength of the formed parts is increased by 10%for AA5754 and by 8%for AA6061.And,the ductility of AA5754 is decreased from 22.9%to 12%and that of AA6061 is decreased from 16%to 10.7%.Regarding the lubricant effect,it is shown that the mechanical properties remain insensitive to the type of lubricant employed.These results indicate that SPIF processing modifies the microstructure of Al alloys in a way to enhance the strength at the cost of ductility.展开更多
Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas mixture.The reactive sputtering technique provides us the flexibility of changing the boron concentration in the prod...Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas mixture.The reactive sputtering technique provides us the flexibility of changing the boron concentration in the produced films by using the same intrinsic zinc oxide target.Textured surface was obtained in the as-deposited films.The surface morphology and the opto-electronic properties of the films can be controlled by simply varying the gas concentration ratio.By varying the gas concentration ratio,the best obtained resistivity ~6.51×10^-4Ω-cm,mobility ~19.05 cm^2 V^-1 s^-1 and sheet resistance ~7.23Ω/□ were obtained.At lower wavelength of light,the response of the deposited films improves with the increase of boron in the gas mixture and the overall transmission in the wavelength region 350-1100 nm of all the films are>85 %.We also fabricated amorphous silicon(a-Si) thin film solar cell on the best obtained BZO layers.The overall efficiency of the a-Si solar cell is 8.14 %,found on optimized BZO layer.展开更多
Organic-inorganic lead halide based perovskite solar cells(PSCs)have attracted unprecedented research interest over last decade.The high performance,combined with merits of low fabrication costs and ease of synthesis ...Organic-inorganic lead halide based perovskite solar cells(PSCs)have attracted unprecedented research interest over last decade.The high performance,combined with merits of low fabrication costs and ease of synthesis make PSCs promising alternate to state of the art silicon(Si)based solar cells.Howeve r,some inherent shortcomings of PSCs are hindering their market dominance over conventional photovoltaic technologies such as transmission loss of sub-bandgap photons,poor stability and hysteresis effects.Recently,use of rare earth(RE)ions doped nanomaterials in PSCs,has been identified as an effective means to address the aforementioned issues by expanding the range of absorption spectra minimizing the non-absorption loss of solar photons,enhancing light scattering and improving operational stability.This article reviews the recent progress in doping rare-earth(RE)ions in the building blocks of PSCs such as semiconductor electrodes and photoactive perovskite layers,and its use as a separate spectral conversion layer in PSCs.The effect of size,shape,constitution and concentration of RE-nanoparticles on the overall performance and device stability will be analyzed in detail.Moreover,we provide an outlook on the opportunities this newly developed field offers and the critical challenges faced in rationally and effectively using RE-ion-doped nanomaterials in PSCs for better operational stability and enhanced performance.展开更多
The paper introduces an electroencephalography(EEG) driven online position control scheme for a robot arm by utilizing motor imagery to activate and error related potential(ErrP) to stop the movement of the individual...The paper introduces an electroencephalography(EEG) driven online position control scheme for a robot arm by utilizing motor imagery to activate and error related potential(ErrP) to stop the movement of the individual links, following a fixed(pre-defined) order of link selection. The right(left)hand motor imagery is used to turn a link clockwise(counterclockwise) and foot imagery is used to move a link forward. The occurrence of ErrP here indicates that the link under motion crosses the visually fixed target position, which usually is a plane/line/point depending on the desired transition of the link across 3D planes/around 2D lines/along 2D lines respectively. The imagined task about individual link's movement is decoded by a classifier into three possible class labels: clockwise, counterclockwise and no movement in case of rotational movements and forward, backward and no movement in case of translational movements. One additional classifier is required to detect the occurrence of the ErrP signal, elicited due to visually inspired positional link error with reference to a geometrically selected target position. Wavelet coefficients and adaptive autoregressive parameters are extracted as features for motor imagery and ErrP signals respectively. Support vector machine classifiers are used to decode motor imagination and ErrP with high classification accuracy above 80%. The average time taken by the proposed scheme to decode and execute control intentions for the complete movement of three links of a robot is approximately33 seconds. The steady-state error and peak overshoot of the proposed controller are experimentally obtained as 1.1% and4.6% respectively.展开更多
The influence of the size of pre-cut hole of blank on the formability of cylindrical hole flanging in single point incremental forming（SPIF） was studied. The flange is produced in four stages starting from 45° ...The influence of the size of pre-cut hole of blank on the formability of cylindrical hole flanging in single point incremental forming（SPIF） was studied. The flange is produced in four stages starting from 45° to 90° and employing aluminum as the test material. It is shown that the hole size has significant effects on the stress/strain distribution on the cylindrical flange. The magnitude of hoop strains increases and the flange thickness increases as the hole size increases. Likewise, the von Mises stress reduces with the increasing of hole size. Further, there is a threshold value of hole size（i.e., 80 mm） below which severe stresses occur, which lead to sheet fracturing thus failing the successful forming of cylindrical flange. Moreover, the formability reduces as the hole size is increased above the threshold size. Finally, it is concluded that 80 mm is the threshold size of hole for maximizing the formability of aluminum sheet in incremental hole flanging.展开更多
Bulge is a defect that causes geometrical inaccuracy and premature failure in the innovative incremental sheet forming (ISF) process. This study has two-fold objectives:(1) knowing the bulging behavior of a Cu clad tr...Bulge is a defect that causes geometrical inaccuracy and premature failure in the innovative incremental sheet forming (ISF) process. This study has two-fold objectives:(1) knowing the bulging behavior of a Cu clad tri-layered steel sheet as a function of forming conditions, and (2) analyzing the bending effect on bulging in an attempt to identify the associated mechanism. A series of ISF tests and bending analysis are performed to realize these objectives. From the cause-effect analysis, it is found that bulge formation in the layered sheet is sensitive to forming conditions in a way that bulging can be minimized utilizing annealed material and performing ISF with larger tool diameter and step size. The bending under tension analysis reveals that the formation of bulge is an outgrowth of bending moment that the forming tool applies on the sheet during ISF. Furthermore, the magnitude of bending moment depending upon the forming conditions varies from 0.046 to 10.24 N·m/m and causes a corresponding change in the mean bulge height from 0.07 to 0.91 mm. The bending moment governs bulging in layered sheet through a linear law. These findings lead to a conclusion that the bulge defect can be overcome by controlling the bending moment and the formula proposed can be helpful in this regards.展开更多
This article presents a multiobjective approach to the design of the controller for the swing-up and handstand control of a general cart-double-pendulum system （CDPS）. The designed controller, which is based on the ...This article presents a multiobjective approach to the design of the controller for the swing-up and handstand control of a general cart-double-pendulum system （CDPS）. The designed controller, which is based on the human-simulated intelligent control （HSIC） method, builds up different control modes to monitor and control the CDPS during four kinetic phases consisting of an initial oscillation phase, a swing-up phase, a posture adjustment phase, and a balance control phase. For the approach, the original method of inequalities-based （MoI） multiobjective genetic algorithm （MMGA） is extended and applied to the case study which uses a set of performance indices that includes the cart displacement over the rail boundary, the number of swings, the settling time, the overshoot of the total energy, and the control effort. The simulation results show good responses of the CDPS with the controllers obtained by the proposed approach.展开更多
A comprehensive theoretical study of entropy generation during electroki-netically driven transport of a nanofluid is of prime concern in the paper. The flow is considered to take place on a wavy channel under the act...A comprehensive theoretical study of entropy generation during electroki-netically driven transport of a nanofluid is of prime concern in the paper. The flow is considered to take place on a wavy channel under the action of an external transverse magnetic field and an external pressure gradient. Navier slips at the walls of the channel and thermal radiation have been taken into account in the study. The theoretical study has been carried out by developing a mathematical model by taking into account the effects of Joule heating, viscous dissipation, and the transverse magnetic field on heat transfer during the electrokinetic transport of the fluid. The derived analytical expres-sions have been computed numerically by considering the nanofluid as a mixture of blood and ferromagnetic nanoparticles. Variations in velocity, streaming potential, temperature distribution, Nusselt number, and Bejan number associated with the electrokinetic flow in capillaries have been investigated by the parametric variation method. The results have been presented graphically. The present investigation reveals that streaming potential decreases due to the Hall effect, while for the cooling capacity of the microsystem, we find an opposite behavior due to the Hall effect. The study further reveals that the fluidic temperature is reduced due to increase in the Hall current, and thereby thermal irreversibility of the system is reduced significantly. The results presented here can be considered as the approximate estimates of blood flow dynamics in capillaries during chemotherapy in cancer treatment.展开更多
Dissimilar joints(DSJs)of ferrous and non-ferrous metals have huge technological importance in the frontiers of newdesigns in new machineries and improved design of conventional systems.This investigation was undertak...Dissimilar joints(DSJs)of ferrous and non-ferrous metals have huge technological importance in the frontiers of newdesigns in new machineries and improved design of conventional systems.This investigation was undertaken to improve mechanicalproperties of joints of two dissimilar metals:one is Ti-based and the other is Fe-based.DSJs were processed using bonding pressurefrom1to9MPa in step of2MPa at750°C for60min.Properties of the DSJs of these two metals using different mechanisms andmethods were compared with the present research for verification.Experimental results from the diffusion bonding mechanism forjoining the dissimilar metals validated the improvement in properties.Superior mechanical properties of dissimilar-metals joints wereachieved mainly due to the third non-ferrous metallic foil,Ni of^200-?m thickness,which avoided the formation of brittleFe-Ti-based intermetallics in the diffusion zone.DSJs processed are able to achieve maximum strength of^560MPa along withsubstantial ductility of^11.9%,which is the best ever reported in the literatures so far.Work hardening effect was detected in theDSJs when the bonding was processed at5MPa and above.Bulging ratio of the non-ferrous metal(Ti-based)was much higher thanthat of the ferrous metal(SS)of the DSJs processed.SEM analysis was carried out to know the details of reaction zone,while XRDwas carried out to support the SEM results.Reasons for change in mechanical,physical,and fracture properties of the DSJs with theprocess parameter variations were clarified.展开更多
The influence of titanium alloy(Ti–5 Al–2.5 Sn) and commercially pure titanium(cp Ti) as fillers on dissimilar pulsed tungsten inert gas weldments of Ti–5 Al–2.5 Sn/cp Ti was investigated in terms of microstructur...The influence of titanium alloy(Ti–5 Al–2.5 Sn) and commercially pure titanium(cp Ti) as fillers on dissimilar pulsed tungsten inert gas weldments of Ti–5 Al–2.5 Sn/cp Ti was investigated in terms of microstructure, mechanical/nano-mechanical properties, and residual stresses. A partial martensitic transformation was observed in the weldments for all the welding conditions due to high heat input. The microstructure evolved in the FZ/cp Ti interfacial region was observed to be the most sensitive to the proportion of α stabilizer in the filler alloy. Furthermore, the addition of filler alloy improved the tensile properties and nano-mechanical response of the weld joint owing to the increased volume of metal in the weld joint. As compared to the Ti–5 Al–2.5 Sn wire, the use of cp Ti filler wire proved to be better in terms of energy absorbed during tensile and impact tests, tensile strength and ductility of the dissimilar welds. An asymmetrical residual stresses profile was observed close to the weld centerline, with high compressive stresses on the Ti–5 Al–2.5 Sn side for both the weldments obtained with and without filler wires. This was attributed to mainly the low thermal conductivity of Ti–5 Al–2.5 Sn. The presence of residual stresses also influenced the nano-hardness profile across the weldments.展开更多
Exchange coupling and magnetic properties of SmCo5 alloys containing different amounts of Sn were investigated in sintered magnets. X-ray diffraction analysis revealed the formation of Sm2Co17 and Sm2Co7 phases in SmC...Exchange coupling and magnetic properties of SmCo5 alloys containing different amounts of Sn were investigated in sintered magnets. X-ray diffraction analysis revealed the formation of Sm2Co17 and Sm2Co7 phases in SmCo5 matrix. Exchange coupling mechanism was evaluated by switching field distribution, dcdemagnetization and magnetization curves as function of reverse applied field. Energy product of 59.2 kJ/m3 （7.4 MGOe）, remanent magnetization to maximum magnetization ratio of 0.97 and remanence coercivity to intrinsic coercivity ratio of 1.75 were achieved for 0.2 at.% Sn.展开更多
Mg-Zn-Zr(ZK)alloys exhibit notably high mechanical strength amongst all magnesium alloy grades.However,due to the formation of low melting point Mg_3Zn_7-precipitates,these alloys are susceptible to hot cracking,thus ...Mg-Zn-Zr(ZK)alloys exhibit notably high mechanical strength amongst all magnesium alloy grades.However,due to the formation of low melting point Mg_3Zn_7-precipitates,these alloys are susceptible to hot cracking,thus compromising their metallurgical processing.The addition of rare earths to ZK alloys is an alternative to form higher melting point intermetallic compounds,speed up dynamic recrystallization,refine grain size,enhance corrosion resistance and extend the service temperature due to improved creep resistance.This work deals with the effect of Ce-base mischmetal addition on the hot rolling behaviour of as-cast ZK60 alloy.The microstructure investigation conducted using electron microscopy and X-Ray diffraction shows that precipitation of Mg_(7)Zn_(3) intermetallics occur during hot rolling,whereas no further precipitation is observed for the ZK60-Mm alloys.The fragmentation of the intermetallic compounds occur during hot rolling and finer particles of Mg_(7)Zn_(3) are observed for the ZK60,whereas Mg_(7)Zn_(3) and Mg Zn_(2) Ce intermetallics are formed in the alloy modified with mischmetal addition.A higher fraction of dynamically recrystallized grains is observed for the ZK60-Mm in comparison to the ZK60.Continuous recrystallization takes place in ZK60 with the formation of sub-grains near to the intermetallics and the addition of mischmetal promotes the occurrence of discontinuous recrystallization with the nucleation of new grains close to the precipitates.The mechanical strength and,in particular,the ductility of the hot-rolled alloys are notably improved when compared to the same alloys in the as-cast condition.The mechanical strength is,however,higher for the ZK60 alloy.Less solid solution strengthening,softer Mg Zn_(2) Ce intermetallics and more extensive recrystallization contribute to reduce the mechanical strength of ZK60-Mm.Failure in both alloys are initiated at coarse intermetallics and propagate through intermetallic-rich regions.展开更多
This paper deals with a peculiar rheological behavior of aluminum at near-solidus temperatures. It has been experimentally estab- lished that there is an inverse strain rate dependence of strain resistance at temperat...This paper deals with a peculiar rheological behavior of aluminum at near-solidus temperatures. It has been experimentally estab- lished that there is an inverse strain rate dependence of strain resistance at temperatures ranging between 560 and 640℃ and strain rates ranging from 0.06 to 1.2 s-1. Electron backscatter diffraction analysis has shown that at temperatures ranging between 540 and 640℃ and strain rates ranging from 0.06 to 0.1 s-1, the main process of softening is dynamic polygonization, resulting in in situ recrystallization. At higher strain rates, ranging between 0.8 and 1.2 s-1, and temperatures ranging between 560 and 640℃, the recovery is dynamic. This unusual behavior of the mechanism of softening and the presence of the inverse strain rate dependence of strain resistance can be explained by blocking the motion of free dislocations by foreign atoms, which occurs at strain rates ranging between 0.06 and 0.1 s-1 This process results in dislocation pile-up, thereby causing in sire recrystallization. At strain rates exceeding 0.16 s-1, there is no intensive blocking of dislocations, leading to a direct strain rate dependence of strain resistance.展开更多
An isothermal kinetic study of a novel technique for reducing agglomerated iron ore by volatiles released by pyrolysis of lean-grade non-coking coal was carried out at temperature from 1050 to 1200℃ for 10-120 min. T...An isothermal kinetic study of a novel technique for reducing agglomerated iron ore by volatiles released by pyrolysis of lean-grade non-coking coal was carried out at temperature from 1050 to 1200℃ for 10-120 min. The reduced samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and chemical analysis. A good degree of metallization and reduction was achieved. Gas diffusion through the solid was identified as the reaction-rate-controlling resistance; however, during the initial period, particularly at lower temperatures, resistance to interfacial chemical reaction was also significant, though not dominant. The apparent rate constant was observed to increase marginally with decreasing size of the particles constituting the nuggets. The apparent activation energy of reduction was estimated to be in the range from 49.640 to 51.220 kJ/mol and was not observed to be affected by the particle size. The sulfur and carbon contents in the reduced samples were also determined.展开更多
It was derived that micro-scale amount level of average pore radius of clay changed from 0.01 to 0.1 micron by an equivalent concept of flow in porous media. There is good agreement between the derived results and tes...It was derived that micro-scale amount level of average pore radius of clay changed from 0.01 to 0.1 micron by an equivalent concept of flow in porous media. There is good agreement between the derived results and test ones. Results of experiments show that flow in micro-scale pore of saturated clays follows law of nonlinear flow. Theoretical analyses demonstrate that an interaction of solid-liquid interfaces varies inversely with permeability or porous radius. The interaction is an important reason why nonlinear flow in saturated clays occurs. An exact mathematical model was presented for nonlinear flow in micro-scale pore of saturated clays. Dimension and physical meanings of parameters of it are definite. A new law of nonlinear flow in saturated clays was established. It can describe characteristics of flow curve of the whole process of the nonlinear flow from low hydraulic gradient to high one. Darcy law is a special case of the new law. A math- ematical model was presented for consolidation of nonlinear flow in radius direction in saturated clays with constant rate based on the new law of nonlinear flow. Equations of average mass conservation and moving boundary, and formula of excess pore pressure distribution and average degree of consolidation for nonlinear flow in saturated clay were derived by using an idea of viscous boundary layer, a method of steady state in stead of transient state and a method of integral of an equation. Laws of excess pore pressure distribution and changes of average degree of consolidation with time were obtained. Re- sults show that velocity of moving boundary decreases because of the nonlinear flow in saturated clay. The results can provide geology engineering and geotechnical engineering of saturated clay with new scientific bases. Calculations of average degree of consolidation of the Darcy flow are a special case of that of the nonlinear flow.展开更多
文摘Motivated by the early works on bidirectional interaction and the breakthrough to estimate seismic response to bidirectional shaking via unidirectional analysis,it is essential to answer the question:When is the interaction effect significant?Early works concluded that the effect of interaction is pronounced for stiff systems;consequently,the straightforward method for estimating seismic response to bidirectional excitation by using unidirectional analyses is verified primarily for short period systems.Hence,it is essential to identify the domain of significance for bidirectional interaction before adopting this simple methodology in design.Several parametrically defined systems with elastoplastic and degrading hysteresis models are studied under near-fault motions,assuming strength-independent and strength-dependent stiffness.The force-based and displacement-based analyses,conducted in parallel,reveal that the interaction effect is considerable for stiff systems,especially with degrading characteristics in a relatively low inelasticity range.However,the bidirectional effect may be significant even for highly flexible systems,especially for residual deformation,which in earlier works was shrouded.The range of significance depends on the hysteresis model,system parameters,and response indices.Regression analysis is carried out with the results of the case studies,and the derived regression models may be used for a preliminary assessment of the impact of interaction in advance.
基金supported by the the University Grants Commission(UGC),Government of India(NTA Ref.No.:211610140697,dated:19th April 2022)supported by the Indian Institute of Engineering Science and Technology,Shibpur。
文摘In this paper,we develop a quantum communication protocol for the simultaneous preparation of a two-qubit and a three-qubit state at the positions of two different parties situated spatially apart.For one party,Alice,it is a remote state preparation of a known two-qubit state while for the other party,Bob,it is a joint remote state preparation with the help of a third party,Eve.The protocol is executed in a hybrid form bi-directionally in the presence of two controllers,Charlie and David.There is a hierarchy in the process through different levels of control under which the actions by Alice and Bob are performed.There is a need for a ten-qubit entangled channel connecting the five parties.The generation of this channel through a circuit is discussed.The protocol is executed on the IBM Quantum platform.We also study the effect of noise on our protocol.Here,amplitude-damping,bit-flip and phase-flip noisy environments are considered and the corresponding variations of fidelity are theoretically and numerically analyzed.
文摘With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its infancy.Thus,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers mobility.The atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device operations.We also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various applications.Presently,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk semiconductors.We also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional junctions.Finally,we talked about the problems and potential for the future.
基金financially supported by the National Natural Science Foundation of China(No.11974184)JiangSu Undergraduate Training Program for Innovation and Entrepreneurship(No.202310288172Y)。
文摘MgZn_(2)-type(Hf,Ta)Fe_(2),known for its negative thermal expansion during magnetic transition,is a key component in the production of zero thermal expansion composites.This paper presents a basic approach for designing such composites by introducing an additional Laves phase through atomic substitution.Specifically,Co,Ni,A1 and V were chosen to substitute Fe in(Hf,Ta)Fe_(2).The addition of Co or Ni results in the creation of an extra MgCu_(2)(C15)phase in the MgZn_(2)(C14)matrix.The C15phase exhibits positive thermal expansion,which effectively compensates for the negative thermal expansion of the C14 matrix.By adjusting the amount of Co or Ni,zero thermal expansion can be achieved in a given temperature range.Meanwhile,the replacement of Fe by Al or V yields another C14 phase with a higher doping element content relative to the C14 matrix.These two C14 phases possess different magnetic transition temperatures and negative thermal expansion temperature regions.The combination of the two C14 phases results in zero thermal expansion due to the effective thermal expansion compensation between them.Our results serve to identify potential approaches for designing(Hf,Ta)Fe_(2)-based zero thermal expansion composites.
基金supported by Higher Education Commission(HEC)of Pakistan under the National Research Program for Universities(NRPU)with project No.5544/KPK/NRPU/R&D/HEC/2016
文摘Novel characteristics of graphene have captured great attention of researchers for energy technology applications.Incorporation of graphene related hybrid and composite materials have demonstrated high performance and durability for fuel cell energy conversion devices.This article overviews graphene based materials for fuel cell technology applications such as electrodes additives,bipolar plates and proton conducting electrolyte membrane.The graphene dispersion over electrodes has revealed enhanced exposure of electrochemically active surface area for improved electro-catalytic activity towards fuel oxidation and oxidant reduction reactions.The issue of device stack durability and degraded performance due to corrosion of bipolar plates is discussed by incorporating graphene based materials.In proton exchange membrane devices,graphene as an electrolyte has shown an excellent performance towards high ionic conductivity and power density.The graphene incorporation in fuel cell devices has exhibited commendable performance and has bright future for commercial applications.
文摘This study performs single point incremental forming(SPIF)on two aluminum alloys(i.e.AA5754 and AA6061),and analyzes their post forming mechanical properties and microstructure evolution.The forming parameters namely wall angle(35°-55°),feed rate(1-4 m/min),spindle rotational speed(50-1000 r/min),and lubricant(grease and hydraulic oil)are varied to probe detailed processing effects.The pre-and post-SPIF mechanical properties and microstructures are characterized by conducting tensile tests and optical microscopy,respectively.It is shown that an increase in the wall angle,feed rate and rotational speed causes microscopic variations in the alloys such that the grains of AA5754 and the second phase particles of AA6061 elongate.As a result,the ultimate tensile strength of the formed parts is increased by 10%for AA5754 and by 8%for AA6061.And,the ductility of AA5754 is decreased from 22.9%to 12%and that of AA6061 is decreased from 16%to 10.7%.Regarding the lubricant effect,it is shown that the mechanical properties remain insensitive to the type of lubricant employed.These results indicate that SPIF processing modifies the microstructure of Al alloys in a way to enhance the strength at the cost of ductility.
基金The work has been supported by the Science and Engineering Research Board(SERB),Department of Science and Technology(SR/FTP/PS-175/2012)。
文摘Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas mixture.The reactive sputtering technique provides us the flexibility of changing the boron concentration in the produced films by using the same intrinsic zinc oxide target.Textured surface was obtained in the as-deposited films.The surface morphology and the opto-electronic properties of the films can be controlled by simply varying the gas concentration ratio.By varying the gas concentration ratio,the best obtained resistivity ~6.51×10^-4Ω-cm,mobility ~19.05 cm^2 V^-1 s^-1 and sheet resistance ~7.23Ω/□ were obtained.At lower wavelength of light,the response of the deposited films improves with the increase of boron in the gas mixture and the overall transmission in the wavelength region 350-1100 nm of all the films are>85 %.We also fabricated amorphous silicon(a-Si) thin film solar cell on the best obtained BZO layers.The overall efficiency of the a-Si solar cell is 8.14 %,found on optimized BZO layer.
基金the financial support provided by Dongguan University of Technology to carry out this extensive research work。
文摘Organic-inorganic lead halide based perovskite solar cells(PSCs)have attracted unprecedented research interest over last decade.The high performance,combined with merits of low fabrication costs and ease of synthesis make PSCs promising alternate to state of the art silicon(Si)based solar cells.Howeve r,some inherent shortcomings of PSCs are hindering their market dominance over conventional photovoltaic technologies such as transmission loss of sub-bandgap photons,poor stability and hysteresis effects.Recently,use of rare earth(RE)ions doped nanomaterials in PSCs,has been identified as an effective means to address the aforementioned issues by expanding the range of absorption spectra minimizing the non-absorption loss of solar photons,enhancing light scattering and improving operational stability.This article reviews the recent progress in doping rare-earth(RE)ions in the building blocks of PSCs such as semiconductor electrodes and photoactive perovskite layers,and its use as a separate spectral conversion layer in PSCs.The effect of size,shape,constitution and concentration of RE-nanoparticles on the overall performance and device stability will be analyzed in detail.Moreover,we provide an outlook on the opportunities this newly developed field offers and the critical challenges faced in rationally and effectively using RE-ion-doped nanomaterials in PSCs for better operational stability and enhanced performance.
基金supported by UGC Sponsored UPE-ⅡProject in Cognitive Science of Jadavpur University,Kolkata
文摘The paper introduces an electroencephalography(EEG) driven online position control scheme for a robot arm by utilizing motor imagery to activate and error related potential(ErrP) to stop the movement of the individual links, following a fixed(pre-defined) order of link selection. The right(left)hand motor imagery is used to turn a link clockwise(counterclockwise) and foot imagery is used to move a link forward. The occurrence of ErrP here indicates that the link under motion crosses the visually fixed target position, which usually is a plane/line/point depending on the desired transition of the link across 3D planes/around 2D lines/along 2D lines respectively. The imagined task about individual link's movement is decoded by a classifier into three possible class labels: clockwise, counterclockwise and no movement in case of rotational movements and forward, backward and no movement in case of translational movements. One additional classifier is required to detect the occurrence of the ErrP signal, elicited due to visually inspired positional link error with reference to a geometrically selected target position. Wavelet coefficients and adaptive autoregressive parameters are extracted as features for motor imagery and ErrP signals respectively. Support vector machine classifiers are used to decode motor imagination and ErrP with high classification accuracy above 80%. The average time taken by the proposed scheme to decode and execute control intentions for the complete movement of three links of a robot is approximately33 seconds. The steady-state error and peak overshoot of the proposed controller are experimentally obtained as 1.1% and4.6% respectively.
文摘The influence of the size of pre-cut hole of blank on the formability of cylindrical hole flanging in single point incremental forming（SPIF） was studied. The flange is produced in four stages starting from 45° to 90° and employing aluminum as the test material. It is shown that the hole size has significant effects on the stress/strain distribution on the cylindrical flange. The magnitude of hoop strains increases and the flange thickness increases as the hole size increases. Likewise, the von Mises stress reduces with the increasing of hole size. Further, there is a threshold value of hole size（i.e., 80 mm） below which severe stresses occur, which lead to sheet fracturing thus failing the successful forming of cylindrical flange. Moreover, the formability reduces as the hole size is increased above the threshold size. Finally, it is concluded that 80 mm is the threshold size of hole for maximizing the formability of aluminum sheet in incremental hole flanging.
基金the financial help and technical support that King Abdulaziz University provided for this research work
文摘Bulge is a defect that causes geometrical inaccuracy and premature failure in the innovative incremental sheet forming (ISF) process. This study has two-fold objectives:(1) knowing the bulging behavior of a Cu clad tri-layered steel sheet as a function of forming conditions, and (2) analyzing the bending effect on bulging in an attempt to identify the associated mechanism. A series of ISF tests and bending analysis are performed to realize these objectives. From the cause-effect analysis, it is found that bulge formation in the layered sheet is sensitive to forming conditions in a way that bulging can be minimized utilizing annealed material and performing ISF with larger tool diameter and step size. The bending under tension analysis reveals that the formation of bulge is an outgrowth of bending moment that the forming tool applies on the sheet during ISF. Furthermore, the magnitude of bending moment depending upon the forming conditions varies from 0.046 to 10.24 N·m/m and causes a corresponding change in the mean bulge height from 0.07 to 0.91 mm. The bending moment governs bulging in layered sheet through a linear law. These findings lead to a conclusion that the bulge defect can be overcome by controlling the bending moment and the formula proposed can be helpful in this regards.
基金supported by the National Science Council, Taiwan(No. 96-2221-E-327-027, No. 96-2221-E-327-005-MY2, and No. 96-2628-E-327-004-MY3).
文摘This article presents a multiobjective approach to the design of the controller for the swing-up and handstand control of a general cart-double-pendulum system （CDPS）. The designed controller, which is based on the human-simulated intelligent control （HSIC） method, builds up different control modes to monitor and control the CDPS during four kinetic phases consisting of an initial oscillation phase, a swing-up phase, a posture adjustment phase, and a balance control phase. For the approach, the original method of inequalities-based （MoI） multiobjective genetic algorithm （MMGA） is extended and applied to the case study which uses a set of performance indices that includes the cart displacement over the rail boundary, the number of swings, the settling time, the overshoot of the total energy, and the control effort. The simulation results show good responses of the CDPS with the controllers obtained by the proposed approach.
基金Project supported by Science and Engineering Research Board(SERB)Department of Science and Technology,Government of India,New Delhi(No.CRG/2018/000153)
文摘A comprehensive theoretical study of entropy generation during electroki-netically driven transport of a nanofluid is of prime concern in the paper. The flow is considered to take place on a wavy channel under the action of an external transverse magnetic field and an external pressure gradient. Navier slips at the walls of the channel and thermal radiation have been taken into account in the study. The theoretical study has been carried out by developing a mathematical model by taking into account the effects of Joule heating, viscous dissipation, and the transverse magnetic field on heat transfer during the electrokinetic transport of the fluid. The derived analytical expres-sions have been computed numerically by considering the nanofluid as a mixture of blood and ferromagnetic nanoparticles. Variations in velocity, streaming potential, temperature distribution, Nusselt number, and Bejan number associated with the electrokinetic flow in capillaries have been investigated by the parametric variation method. The results have been presented graphically. The present investigation reveals that streaming potential decreases due to the Hall effect, while for the cooling capacity of the microsystem, we find an opposite behavior due to the Hall effect. The study further reveals that the fluidic temperature is reduced due to increase in the Hall current, and thereby thermal irreversibility of the system is reduced significantly. The results presented here can be considered as the approximate estimates of blood flow dynamics in capillaries during chemotherapy in cancer treatment.
文摘Dissimilar joints(DSJs)of ferrous and non-ferrous metals have huge technological importance in the frontiers of newdesigns in new machineries and improved design of conventional systems.This investigation was undertaken to improve mechanicalproperties of joints of two dissimilar metals:one is Ti-based and the other is Fe-based.DSJs were processed using bonding pressurefrom1to9MPa in step of2MPa at750°C for60min.Properties of the DSJs of these two metals using different mechanisms andmethods were compared with the present research for verification.Experimental results from the diffusion bonding mechanism forjoining the dissimilar metals validated the improvement in properties.Superior mechanical properties of dissimilar-metals joints wereachieved mainly due to the third non-ferrous metallic foil,Ni of^200-?m thickness,which avoided the formation of brittleFe-Ti-based intermetallics in the diffusion zone.DSJs processed are able to achieve maximum strength of^560MPa along withsubstantial ductility of^11.9%,which is the best ever reported in the literatures so far.Work hardening effect was detected in theDSJs when the bonding was processed at5MPa and above.Bulging ratio of the non-ferrous metal(Ti-based)was much higher thanthat of the ferrous metal(SS)of the DSJs processed.SEM analysis was carried out to know the details of reaction zone,while XRDwas carried out to support the SEM results.Reasons for change in mechanical,physical,and fracture properties of the DSJs with theprocess parameter variations were clarified.
文摘The influence of titanium alloy(Ti–5 Al–2.5 Sn) and commercially pure titanium(cp Ti) as fillers on dissimilar pulsed tungsten inert gas weldments of Ti–5 Al–2.5 Sn/cp Ti was investigated in terms of microstructure, mechanical/nano-mechanical properties, and residual stresses. A partial martensitic transformation was observed in the weldments for all the welding conditions due to high heat input. The microstructure evolved in the FZ/cp Ti interfacial region was observed to be the most sensitive to the proportion of α stabilizer in the filler alloy. Furthermore, the addition of filler alloy improved the tensile properties and nano-mechanical response of the weld joint owing to the increased volume of metal in the weld joint. As compared to the Ti–5 Al–2.5 Sn wire, the use of cp Ti filler wire proved to be better in terms of energy absorbed during tensile and impact tests, tensile strength and ductility of the dissimilar welds. An asymmetrical residual stresses profile was observed close to the weld centerline, with high compressive stresses on the Ti–5 Al–2.5 Sn side for both the weldments obtained with and without filler wires. This was attributed to mainly the low thermal conductivity of Ti–5 Al–2.5 Sn. The presence of residual stresses also influenced the nano-hardness profile across the weldments.
文摘Exchange coupling and magnetic properties of SmCo5 alloys containing different amounts of Sn were investigated in sintered magnets. X-ray diffraction analysis revealed the formation of Sm2Co17 and Sm2Co7 phases in SmCo5 matrix. Exchange coupling mechanism was evaluated by switching field distribution, dcdemagnetization and magnetization curves as function of reverse applied field. Energy product of 59.2 kJ/m3 （7.4 MGOe）, remanent magnetization to maximum magnetization ratio of 0.97 and remanence coercivity to intrinsic coercivity ratio of 1.75 were achieved for 0.2 at.% Sn.
基金funding of FAPESP,processes 2010/11391-2,2011/09324-8,2011/19218-0FAPESP and CNPQ for the scholarshipsthe funding provided by CAPES(PROBRAL project 88881.143948/2017-01)。
文摘Mg-Zn-Zr(ZK)alloys exhibit notably high mechanical strength amongst all magnesium alloy grades.However,due to the formation of low melting point Mg_3Zn_7-precipitates,these alloys are susceptible to hot cracking,thus compromising their metallurgical processing.The addition of rare earths to ZK alloys is an alternative to form higher melting point intermetallic compounds,speed up dynamic recrystallization,refine grain size,enhance corrosion resistance and extend the service temperature due to improved creep resistance.This work deals with the effect of Ce-base mischmetal addition on the hot rolling behaviour of as-cast ZK60 alloy.The microstructure investigation conducted using electron microscopy and X-Ray diffraction shows that precipitation of Mg_(7)Zn_(3) intermetallics occur during hot rolling,whereas no further precipitation is observed for the ZK60-Mm alloys.The fragmentation of the intermetallic compounds occur during hot rolling and finer particles of Mg_(7)Zn_(3) are observed for the ZK60,whereas Mg_(7)Zn_(3) and Mg Zn_(2) Ce intermetallics are formed in the alloy modified with mischmetal addition.A higher fraction of dynamically recrystallized grains is observed for the ZK60-Mm in comparison to the ZK60.Continuous recrystallization takes place in ZK60 with the formation of sub-grains near to the intermetallics and the addition of mischmetal promotes the occurrence of discontinuous recrystallization with the nucleation of new grains close to the precipitates.The mechanical strength and,in particular,the ductility of the hot-rolled alloys are notably improved when compared to the same alloys in the as-cast condition.The mechanical strength is,however,higher for the ZK60 alloy.Less solid solution strengthening,softer Mg Zn_(2) Ce intermetallics and more extensive recrystallization contribute to reduce the mechanical strength of ZK60-Mm.Failure in both alloys are initiated at coarse intermetallics and propagate through intermetallic-rich regions.
基金financially supported by Russian Science Foundation(No. 14-19-01358)
文摘This paper deals with a peculiar rheological behavior of aluminum at near-solidus temperatures. It has been experimentally estab- lished that there is an inverse strain rate dependence of strain resistance at temperatures ranging between 560 and 640℃ and strain rates ranging from 0.06 to 1.2 s-1. Electron backscatter diffraction analysis has shown that at temperatures ranging between 540 and 640℃ and strain rates ranging from 0.06 to 0.1 s-1, the main process of softening is dynamic polygonization, resulting in in situ recrystallization. At higher strain rates, ranging between 0.8 and 1.2 s-1, and temperatures ranging between 560 and 640℃, the recovery is dynamic. This unusual behavior of the mechanism of softening and the presence of the inverse strain rate dependence of strain resistance can be explained by blocking the motion of free dislocations by foreign atoms, which occurs at strain rates ranging between 0.06 and 0.1 s-1 This process results in dislocation pile-up, thereby causing in sire recrystallization. At strain rates exceeding 0.16 s-1, there is no intensive blocking of dislocations, leading to a direct strain rate dependence of strain resistance.
基金financial support from Technical Quality Improvement Programme (TEQIP) phase-IIJadavpur University towards fellowship is also acknowledged
文摘An isothermal kinetic study of a novel technique for reducing agglomerated iron ore by volatiles released by pyrolysis of lean-grade non-coking coal was carried out at temperature from 1050 to 1200℃ for 10-120 min. The reduced samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and chemical analysis. A good degree of metallization and reduction was achieved. Gas diffusion through the solid was identified as the reaction-rate-controlling resistance; however, during the initial period, particularly at lower temperatures, resistance to interfacial chemical reaction was also significant, though not dominant. The apparent rate constant was observed to increase marginally with decreasing size of the particles constituting the nuggets. The apparent activation energy of reduction was estimated to be in the range from 49.640 to 51.220 kJ/mol and was not observed to be affected by the particle size. The sulfur and carbon contents in the reduced samples were also determined.
基金Project supported by the National Natural Science Foundation of China (Nos.40202036,40572163,50579042)the Youth Science Foundation of Siehuan Province of China (No.05ZQ026-043)+1 种基金the Science Foundation of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(No.GZ2004-05)the Postdoctoral Science Foundation of China (No.35)
文摘It was derived that micro-scale amount level of average pore radius of clay changed from 0.01 to 0.1 micron by an equivalent concept of flow in porous media. There is good agreement between the derived results and test ones. Results of experiments show that flow in micro-scale pore of saturated clays follows law of nonlinear flow. Theoretical analyses demonstrate that an interaction of solid-liquid interfaces varies inversely with permeability or porous radius. The interaction is an important reason why nonlinear flow in saturated clays occurs. An exact mathematical model was presented for nonlinear flow in micro-scale pore of saturated clays. Dimension and physical meanings of parameters of it are definite. A new law of nonlinear flow in saturated clays was established. It can describe characteristics of flow curve of the whole process of the nonlinear flow from low hydraulic gradient to high one. Darcy law is a special case of the new law. A math- ematical model was presented for consolidation of nonlinear flow in radius direction in saturated clays with constant rate based on the new law of nonlinear flow. Equations of average mass conservation and moving boundary, and formula of excess pore pressure distribution and average degree of consolidation for nonlinear flow in saturated clay were derived by using an idea of viscous boundary layer, a method of steady state in stead of transient state and a method of integral of an equation. Laws of excess pore pressure distribution and changes of average degree of consolidation with time were obtained. Re- sults show that velocity of moving boundary decreases because of the nonlinear flow in saturated clay. The results can provide geology engineering and geotechnical engineering of saturated clay with new scientific bases. Calculations of average degree of consolidation of the Darcy flow are a special case of that of the nonlinear flow.
