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Superelastic NiTi shape memory alloy (SMA) has high recoverable strain and outstanding damping capacity, and has been used as a damping material for many applications. When subjected to displacement-controlled cyclic deformation, the material exhibits distinctive temperature and stress oscillations due to the release of latent heat and hysteresis heat and the heat transfer with the ambient. In this paper, we establish a model to predict the temperature variation of NiTi SMA wire specimen under the cyclic phase transition by lumped heat transfer analysis. Closed-form solution on the evolution of the temperature is obtained. It is shown that, for all the test frequencies, steady-state cyclic thermal response of the specimen can be reached after a certain number of loading cycles in a transient stage, exhibiting a kind of “thermal shake down.” In the steady state, the temperature profile oscillates around a mean temperature plateau. We show that the temperature oscillation is mainly due to the release/absorption of latent heat during cyclic phase transition, while the mean temperature rise of the specimen is caused by the accumulation of the hysteretic heat of the phase transition. The model predictions agree well with the experimental results.

This article presents an experimental investigation on failure strengths and mechanical responses of transversely isotropic slates under the compressive differential cyclic loading. The tests involve five bedding orientations (0°, 30°, 45°, 60°, 90°) and two loading modes. The tests aim to investigate the coupled influence of the distinct loading/unloading rates and bedding orientation on the anisotropic characteristics, incl. the deformability, energy dissipation, damping ratio, phase shift and failure patterns. The results show that both loading modes and bedding angles have impacts on the mechanical responses of slates. Specifically, it is observed that rapid loading and slow unloading result in a higher growth rate of peak/residual strain versus cycle number as well as more intensive energy dissipation, and correspond to more significant phase shift. The influence of bedding angles on energy dissipation and strain is less pronounced compared to the effects of differential cyclic loading. The nuclear magnetic resonance was used to analyze the T2 spectra of the failed samples with different bedding angles.Highlights Rapid loading and slow unloading tend to intensify the phase shift at peak stress, while their effect on minimum stress remains unpronounced.Rapid loading and slow unloading tend to cause larger energy dissipation under different bedding angles.The modified Jaeger's plane of weakness model can well capture rock strengths across varying bedding angles when subjected to differential cyclic loading.

The formation mechanism of FCC phase on prismatic-basal (PB) interfaces in 101¯2 < 1¯011> twin in Zircaloy-4 under cyclic deformation at the strain level of 1.0% was systematically investigated by using transmission electron microscopy. Results showed that 101¯2 < 1¯011> twin was presented in α-Zr grain and PB interfaces can be introduced into the twin boundaries. Under cyclic stresses, the emission of 1/3[01¯10] and 1/3 [011¯0] Shockley partial dislocations would be initiated on the PB interfaces of the twin and slipped symmetrically on every other (0001) planes of the twin, resulting in the HCP → FCC phase transformation. Moreover, when the shear stresses were large enough, 1/6 < 1¯1¯2> Shockley partial dislocations were activated during cyclic deformation and the formation of 111 SFs in FCC phase was presented.

The motion of electrons in a solid has a profound effect on its topological properties and may result in a nonzero Berry's phase, a geometric quantum phase encoded in the system's electronic wave function. Despite its ubiquity, there are few experimental observations of Berry's phase of bulk states. Here, we report detection of a nontrivial π Berry's phase in the bulk Rashba semiconductor BiTel via analysis of the Shubnikov-de Haas (SdH) effect. The extremely large Rashba splitting in this material enables the separation of SdH oscillations, stemming from the spin-split inner and outer Fermi surfaces. For both Fermi surfaces, we observe a systematic π-phase shift in SdH oscillations, consistent with the theoretically predicted nontrivial π Berry's phase in Rashba systems.

Phase relations between quantum states represent a resource for storing and processing quantum information. Although quantum phases are commonly controlled dynamically by tuning energetic interactions, the use of geometric phases that accumulate during cyclic evolution may offer superior robustness to noise. To date, demonstrations of geometric phase in solid-state systems employ microwave fields that have limited spatial resolution. Here, we demonstrate an all-optical method to accumulate a geometric phase, the Berry phase, in an individual nitrogen–vacancy centre in diamond. Using stimulated Raman adiabatic passage controlled by diffraction-limited laser light, we loop the nitrogen–vacancy centre's spin around the Bloch sphere to enclose an arbitrary Berry phase. We investigate the limits of this control due to the loss of adiabaticity and decoherence, as well as its robustness to noise introduced into the experimental control parameters. These techniques set the foundation for optical geometric manipulation in photonic networks of solid-state qubits linked and controlled by light. An all-optical manipulation of the Berry phase based on stimulated Raman adiabatic passage is demonstrated in an individual nitrogen–vacancy centre in diamond. The adiabatic control is 100 times faster than that demonstrated before in atomic systems.

Element-element bonded multiply charged cationic species are well known as dimers or small cyclic oligomers in the condensed phase. However, the smallest acyclic version, a trinuclear unit possessing greater than a monocationic charge, has remained elusive. Here we introduce a bis(phosphine) supported low valent triantimony-based tricationic compound as a new entrant in this field. Structural elucidation and electronic understanding reveal a W-shaped tricationic unit comprising of a three-center four-electron sigma-bonded triantimony moiety that is terminally capped by bis(phosphine) ligands, with the central antimony atom having two lone pairs of electrons. The unique counter trianion [Sb(O) 2 (OTf) 4 ] 3– (OTf = CF 3 SO 3 ) possesses reactive polar Sb δ+ –O δ– bonds, the structure of which is determined from single crystal X-ray diffraction analysis. The ensemble of reactive molecular fragments found in this highly charged antimony-based compound makes it thermally unstable. Nonetheless, this fully characterized fleeting species shows a diverse reactivity profile, advancing the isolation of various novel antimony compounds, including the formation of a distinct low-valent antimony-cobalt carbonyl cluster. Element-element bonded multiply charged cationic species are well known as dimers or small cyclic oligomers in the condensed phase but the smallest acyclic version, a trinuclear unit possessing greater than a monocationic charge, has remained elusive. Here the authors report a bis(phosphine) supported low valent triantimony-based tricationic compound.

High surface area β-Co(OH) 2 nanosheets is electro-synthesized through a simple deposition procedure, and their performance as supercapacitor electrode material is investigated. Cathodic electrodeposition of cobalt hydroxide was performed from 0.005 M CoCl 2 at the direct current (DC) mode with applying current density of 10 mA cm −2 and RT conditions. The obtained green deposit was characterized through XRD, IR, SEM, BET and TEM analyses. The result indicated that the electrodeposited sample has pure beta cobalt hydroxide phase with uniform hexagonal sheets. BET analysis showed that the prepared hydroxide has high surface area of 157.2 m 2  g −1 with mesoscale pores. The charge storage ability of the prepared β-Co(OH) 2 nanosheets were measured by cyclic voltammetry and continuous charge–discharge techniques, which revealed that the produced nanosheets are capable to deliver specific capacitance as high as 886.8 and 734.3 Fg −1 at the current loads of 1 and 3 A g −1 , respectively, and capacity retentions of 93.9 and 83.7% after 3000 continuous cycling at these current loads. These electrochemical data proved the suitability of the prepared material for use in supercapacitor.

Conventional hydraulic actuation supply and control systems usually work with a very high energy loss, especially in the field of off-road machinery. In particular, during the lowering phase of a boom of a hydraulic excavator, energy dissipated through lamination in thermal heat is a consistent fraction of the energy required for operating the working cycle. In this paper, an innovative system is presented that can recover a significant fraction of this energy, to make it available for the next working cycle, which adapts the level of energy recovery in order to maximise the overall efficiency. In the presented system, the conventional hydraulic actuators that operate the boom of a large size hydraulic excavator are replaced with three-chamber actuators, in which the third chamber, obtained inside the cylinder rod, is connected to a secondary hydraulic circuit that involves a series of accumulators: the compression and the subsequent expansion of the amount of gas inside the accumulator allows to, respectively, store the maximum possible recoverable energy, during load lowering phase in the first cycle and deploy it in the next cycle. The initial gas pressure inside the accumulator is set accordingly to the maximum amount of recoverable energy during the cyclic operation, and can be easily changed via a low-displacement auxiliary pump and a feedback control mechanism, without the need of stopping the machine to vary the amount of inert gas inside the accumulators. A hydraulic manifold has been designed to manage and regulate the flow rates of both the main and the secondary circuits. Pressure losses inside the manifold have been evaluated through CFD analysis, performed in SimericsMP+ environment. The whole system has then been simulated as a lumped parameter model developed in Simcenter Amesim ©. Results from the simulation of the proposed system show that, on a working cycle of 20 s, only 25% of the hydraulic energy required for the conventional system is needed to operate the boom in the proposed configuration. This method can be easily extended to several hydraulic actuators that realise frequent height changes of the load.

The naturally deposited soil usually does not consist of pure coarse or fine-grained soil but of a mixture of both. The mechanical behaviour of a saturated fine sand mixed with varying amounts of low-plastic fines was evaluated by monotonic as well as high-cyclic triaxial tests. The test results were used to conclude on the effect of fines content on the critical state, phase transformation line, secant Young’s modulus, the residual strain accumulation as well as strain amplitude during drained cycles of the mixtures in relation to the global void ratio as well as to the equivalent void ratio. It was found that while the choice of void ratio definition is important for the uniqueness of the critical void ratio, both approaches can be used as state variables for the phase transformation line. However, some seemingly contradictive results are found from the drained high-cyclic tests. Eventhough, an increase of the residual strain accumulation with decreasing fines content compared at the same initial equivalent void ratio is rendered by the laboratory data, a unique and on fines content independent relationship between ε acc could be established only with respect to the initial global void ratio.

This paper is devoted to the research of the isomorphic multidimensional cyclic structure and multidimensional phase structure of the cyclic random process (CRP) and to its formation method, which enables a rigorous formalization of intuitive ideas concerning cyclic stochastic motion. The fundamental properties of the cyclic random process and analytical dependencies between the multidimensional cyclic structure, multidimensional phase structure and rhythm structure of the CRP have been established. This work shows that the CRP is able to take into account the cyclicity of multidimensional distribution functions of cyclic signals as well as the variability in the rhythm of the investigated signals. A subclass of the CRP is the periodic random process, which allows for the use of classical processing methods of cyclic signals with a regular rhythm. Based on a series of experiments, significant advantages of the CRP as a mathematical model of electrocardiographic signals (ECG) compared to the periodic random process are shown.