Memory Effect Research Articles

Analyzing election trends incorporating memory effect through a fractional-order mathematical modeling

This study proposes a new mathematical model to analyze and predict the results of a political election. In general, we predict or analyze the results using statistical methods; however, to minimize the effort of the study, we propose a fractional-order modeling approach. This study proposes a model to analyze and predict general election result trends in India, focusing on the state of West Bengal. To incorporate memory into the model, we consider the Caputo fractional derivative. The model solution’s positivity, boundedness, existence, and uniqueness were tested analytically. Numerical simulations were carried out to investigate the impact of the parameters and evaluate the model’s performance by incorporating the implications of the previous election for realistic situations. Following this, a qualitative analysis of the performance of political parties is discussed, and a prediction of the electoral victory is obtained.

Memory effect of gravitational wave pulses in PP-wave spacetimes

In this paper, we study the gravitational memory effect in pp-wave spacetimes due to the passage of a pulse having the form of a ramp profile through this spacetime. We have analyzed the effect of this pulse on the evolution of nearby geodesics, and have determined analytical solutions of the geodesic equations in the Brinkmann coordinates. We have also examined the changes in the separation between a pair of geodesics and their velocity profiles. The separation (along x or y-direction) increases monotonically from an initial constant value. In contrast, the relative velocity grows from zero and settles to a final non-zero constant value. These resulting changes are retained as memory after the pulse dies out. The nature of this memory is similar to that determined by earlier workers using Gaussian, square, and other pulse profiles, thereby validating the universality of gravitational wave memory.

Coexistance of the Negative Photoconductance Effect and Analogue Switching Memory in the CuPc Organic Memristor for Neuromorphic Vision Computing.

A bioinspired in-sensing computing paradigm using emerging photoelectronic memristors pursues multifunctionality with low power consumption and high efficiency for processing large amounts of sensing information. An organic semiconductor memristor strategy based on the CuPc functional layer integrates a negative photoconductance (NPC) effect and an analogue switching memory (ASM) effect in the same pixel. The NPC effect, present in the pure capacitance state at low bias voltage, provides high-performance short/long-term synaptic plasticity modulable by light pulse parameters. The interface charge effect along with defeat site trapping and detrapping is responsible for the pure capacitance effect and the NPC effect, with electron tunneling and electric-field-driven band dynamics responsible for ASM. This work reveals an organic memristor approach for hardware implementation of a neuromorphic vision computing system, emulating retinal bipolar cells via light-dominated NPC and electrically induced ASM with stable, tunable conductance states.

Correlation Between Li-Fe Anti-Site and Memory Effect of LiFePO4 in Li-Ion Batteries.

In Li-ion batteries, the origin of memory effect in Al-doped Li4Ti5O12 has been revealed as the reversible Al-ion switching between 8a and 16c sites in the spinel structure, but it is still not clear about that for olivine LiFePO4, which is one of the most important cathode materials. In this work, a series of Na-doped and Ti-doped LiFePO4 are prepared in a high-temperature solid-state method, electrochemically investigated in Li-ion batteries and characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Magic-Angle-Spinning Nuclear Magnetic Resonance (MAS NMR). Compared with non-doped LiFePO4, the Ti doping can simultaneously suppress the memory effect and the Li-Fe anti-site, while they are simultaneously enhanced by the Na doping. Meanwhile, the Ti doping improves the electrochemical performance of LiFePO4, opposite to the Na doping. Accordingly, a schematic diagram of phase transition is proposed to interpret the memory effect of LiFePO4, in which the memory effect is attributed to the defect of Li-Fe anti-site.

Gravitational wave displacement and velocity memory effects

In this article, we compare in detail the linear and nonlinear approach to the Gravitational Waves Displacement and Velocity Memory (GWDM and GWVM) effects. We consider astrophysical situations that give rise to gravitational waves with GWVM effect, i.e. with a residual velocity (the so-called ‘velocity-coded memory’) and discuss the possibility of future detection of the GWVM effect.

Relevance of Specific Surface of Mixed Oxide Derived from Layered Double Hydroxides on the Rheological Properties and Porosity of Cement Pastes.

Cement-based products are the synthetic materials most used by humans, with consequent environmental impacts. One strategy that can assist in mitigating the adverse environmental effects of these materials involves the incorporation of multifunctional nanostructured additives. The objective of this work was to demonstrate the efficacy of incorporating mixed oxides (MO) derived from layered double hydroxides (LDH) to control the rheology and porosity of cement-based matrices. Thermal aging of LDH enabled the preparation of MO with different specific surface areas (SSA) for incorporation in different amounts in Portland cement. A low proportion of MO and low SSA increased workability by 22%. In contrast, a high proportion of MO and high SSA led to a 2.4-fold acceleration of cement consolidation and a 36.9% decrease of the porosity of the composite. These features could be attributed to additive-matrix interactions, with the LDH memory effect playing key roles in the cement crystal seed process and in competition for the absorption of free water within the cement paste. Therefore, the unprecedent results obtained suggest that the quantity and SSA of MO are key parameters to fine-tune the paste rheology and structure of hidrated cement. The MO materials showed easy adaptability and excellent potential for use as multifunctional additives in the production of eco-friendly, high-performance cement paste formulations with controllable properties according to the desired application.

Fully 3D-Printed Miniature Soft Hydraulic Actuators with Shape Memory Effect for Morphing and Manipulation.

Miniature shape-morphing soft actuators driven by external stimuli and fluidic pressure hold great promise in morphing matter and small-scale soft robotics. However, it remains challenging to achieve both rich shape morphing and shape locking in a fast and controlled way due to the limitations of actuation reversibility and fabrication. Here, fully 3D-printed, sub-millimeter thin-plate-like miniature soft hydraulic actuators with shape memory effect (SME) for programable fast shape morphing and shape locking, are reported. It combines commercial high-resolution multi-material 3D printing of stiff shape memory polymers (SMPs) and soft elastomers and direct printing of microfluidic channels and 2D/3D channel networks embedded in elastomers in a single print run. Leveraging spatial patterning of hybrid compositions and expansion heterogeneity of microfluidic channel networks for versatile hydraulically actuated shape morphing, including circular, wavy, helical, saddle, and warping shapes with various curvatures, are demonstrated. The morphed shapes can be temporarily locked and recover to their original planar forms repeatedly by activating SME of the SMPs. Utilizing the fast shape morphing and locking in the miniature actuators, their potential applications in non-invasive manipulation of small-scale objects and fragile living organisms, multimodal entanglement grasping, and energy-saving manipulators, are demonstrated.

Designing Advanced Amorphous/Nanocrystalline Alloys by Controlling the Energy State.

Amorphous alloys, also known as metallic glasses, exhibit many advanced mechanical, physical, and chemical properties. Owing to the nonequilibrium nature, their energy states can vary over a wide range. However, the energy relaxation kinetics are very complex and composed of various types that are coupled with each other. This makes it challenging to control the energy state precisely and to study the energy-properties relationship. This brief review introduces the recent progresses on studying the enthalpy relaxation kinetics during isothermal annealing, for example, the observation of two-step relaxation phenomenon, the detection of relaxation unit (relaxun), the key role of large activation entropy in triggering memory effect, the influence of glass energy state on nanocrystallization. Based on the above knowledge, a new strategy is proposed to design a series of amorphous alloys and their composites consisting of nanocrystals and glass matrix with superior functional properties by precisely controlling the nonequilibrium energy states. As the typical examples, Fe-based amorphous alloys with both advanced soft magnetism and good plasticity, Gd-based amorphous/nanocrystalline composites with large magnetocaloric effect, and Fe-based amorphous alloys with high catalytic performance are specifically described.

Three-dimensional GRMHD simulations of rapidly rotating stellar core-collapse

Abstract We present results from fully general relativistic (GR), three-dimensional (3D), neutrino-radiation magneto-hydrodynamic (MHD) simulations of stellar core collapse of a 20 M⊙ star with spectral neutrino transport. Our focus is to study the gravitational-wave (GW) signatures from the magnetorotationally (MR)-driven models. By parametrically changing the initial angular velocity and the strength of the magnetic fields in the core, we compute four models. Among our models, only those with cores having an initial magnetic field strength of 1012 G and rotation rates of 1 or 2 rad s−1 produce MHD jets. Seen from the direction perpendicular to the rotational axis, a characteristic waveform is obtained exhibiting a monotonic time increase in the wave amplitude. As previously identified, this stems from the propagating MHD outflows along the axis. We show that the GW amplitude from anisotropic neutrino emission becomes more than one order-of-magnitude bigger than that from the matter contribution, whereas seen from the rotational axis, both of the two components are in the same order-of-magnitudes. Due to the memory effect, the frequency of the neutrino GW from our full-fledged 3D-MHD models is in the range less than ∼10 Hz. Toward the future GW detection for a Galactic core-collapse supernova, if driven by the MR mechanism, the planned next-generation detector as DECIGO is urgently needed to catch the low-frequency signals.

Infrared light responsive shape memory tracheal stent based on TPU6/PCL4/PANI composites

3D printed tracheal stent based on light-responsive shape memory composites (SMC) has a good application prospect due to its remote, non-contact drive and the ability to adapt to complex environments. This paper detailed the fabrication, characterization, and infrared light (IR) actuating shape memory effects of the SMC based on the thermal polyurethane (TPU)/poly(caprolactone) (PCL)/polyaniline (PANI)/composites. Herein, the experiments have explored the preparation and process parameters and 3D printing properties (e.g., filament-molding temperature, 3D printing temperature, and speed) on the premise of smooth printing of the composites. The thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy analysis (FTIR), differential scanning calorimetry analysis (DSC), micro-morphology, and tensile testing was operated to characterize the properties of the TPU6/PCL4/PANI composites. Additionally, shape memory performance has shown that the shape memory fixation rate of the prepared IR-responsive SMC was about 99%, and the shape recovery ratio was approximately 95%. Therefore, this work customized the tracheal scaffold based on TPU6/PCL4/PANI composites by 3D printing technology (FDM), which possesses excellent IR-triggered remote-controlling structure deformation performance. Moreover, by collaborating with minimally invasive surgery, 3D printed IR-actuating SMC structures can expand the application scope in the biomedical field and provide a new way for personalized implantable medical devices.

Better source memory for remembered to-be-forgotten items than for remembered to-be-remembered items.

When participants study items one-by-one and are directed to either remember or forget the respective item directly after its presentation, retention of to-be-forgotten items is regularly worse than of to-be-remembered items. We tested whether this directed forgetting effect which is regularly observed for item memory generalizes to source memory. In three experiments, participants studied items in two different source colors (N = 101) or at two different source locations (N = 64; N = 81). Sources were manipulated orthogonally to item type (remember vs. forget). At test, we asked participants to recognize all studied items and also to identify their source. We used a multinomial processing tree model to disentangle item memory, source memory, and guessing. In all three experiments, we replicated the directed forgetting effect in item memory. Source memory for to-be-forgotten items that were recognized despite the intention to forget, however, tended to be even better than source memory for to-be-remembered items that were recognized. These results suggest that the directed forgetting effect does not simply translate from item to source memory. Rather source memory seems to be disproportionally increased in to-be-forgotten items that are remembered. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

High-gamma and beta bursts in the Left Supramarginal Gyrus can accurately differentiate verbal memory states and performance.

Positive and negative subsequent memory effects have been reported in the left supramarginal gyrus (LSMG) which is thought to mediate attention to memory. We performed a secondary analysis of 142 verbal delayed free recall experiments, in patients with medically refractory epilepsy, undergoing pre-surgical evaluation with electrode contacts implanted in the LSMG. Convolutional neural networks (CNNs), utilizing high-gamma and beta bursts in the LSMG during the word encoding epoch, had an area under the receiver operating curve (AUROC) for classifying remembered words of >0.6 in 16 experiments. These experiments were distinguished by higher peak amplitudes of high-gamma and beta bursts and electrode placement in more anterior and dorsal regions of the LSMG. Among these 16 experiments the CNN utilizing high-gamma and beta bursts was equivalent, or outperformed, the equivalent CNN utilizing raw intracranial electroencephalogram (iEEG). In 7 of these 16 experiments, we also trained and tested CNNs that differentiated verbal word encoding from recall, and better performance recall from poor performance recall. These CNNs also utilized the high-gamma and beta bursts from the respective iEEG epochs. For many of the experiments these CNNs had an AUROC >0.6 demonstrating proof of principle that memory state and performance biomarkers can be derived from highgamma and beta bursts in the iEEG recordings of the LSMG alone.

Kondo enabled transmutation between spinons and superconducting vortices: Origin of magnetic memory in 4Hb−TaS2

Recent experiments [Persky , ] demonstrate a magnetic memory effect in 4Hb−TaS2 above its superconducting transition temperature, where Abriokosov vortices are spontaneously generated by lowering the temperature at zero magnetic field after field training the normal state. Motivated by the experiment, we propose the chiral quantum spin liquid (QSL) stabilized in the constituent layers of 4Hb−TaS2 as a mechanism. We model 4Hb−TaS2 as coupled layers of the chiral QSL and the superconductor. Through the Kondo coupling between the localized moments and conduction electrons, there is mutual transmutation between spinons and vortices during the thermal-cycling process, which yields the magnetic memory effect observed in experiments. We also propose a mechanism to stabilize chiral and nematic superconductivity in 4Hb−TaS2 through the Kondo coupling of conduction electrons to the chiral QSL. Our picture suggests 4Hb−TaS2 as an exciting platform to explore the interplay between QSL and superconductivity through the Kondo effect. Published by the American Physical Society 2024

DESIGN, IMPLEMENTATION, AND TESTING OF A 3D-PRINTED GRIPPER ACTUATED BY NITINOL SPRINGS

This article explores the use of shape memory alloy (SMA) materials in the creation of robot effectors. Specifically, we focus on the design and implementation of a gripper powered by nitinol springs. Nitinol, an alloy of nickel and titanium, can return to a pre-set shape when heated - a phenomenon known as the shape memory effect - which we utilize to control the gripper. The article showcases the design, construction, and testing of the gripper, including its speed and reliability in grasping different objects. Our findings indicate that the gripper was reliable solution, but further research is necessary to optimize its functions and control for more efficient results in practical applications.

Electrical discharge shape memory alloying of Ti-6Al-4V: Mechanisms and mechanical properties

Electric discharge alloying presents an alternate coating process for improving mechanical properties through physical and metallurgical modification. Ti-6Al-4 V is a titanium alloy used in aerospace industry and biomechanical applications but has limitations in terms of wear resistance. Alloying with nickel could provide improvements in terms of wear and other tribological properties. Nickel as an alloying element provides pseudo-elastic behaviour (such as two-way shape memory effect) by changing α-Ti to β-Ti. After coating process, surface hardness of the samples increased up to 684 HV0.5 while in the cross-section, it ranged up to 580 HV0.5. Due to porosity, areas with hardness below the base material hardness value of 260 HV0.5 were measured as well. At the lowest load, coefficient of friction had a value of 1.1 while at higher loads it decreased down to 0.8 compared with alloyed layer with average values of 0.3 to 0.7. Wear resistance properties of titanium were improved as well. Specific wear rate under 40 N was 1.0 × 10−5 N/mm2 showing higher wear resistance with minimal ploughing.

Uncalcined Zn/Al Carbonate LDH and Its Calcined Counterpart for Treating the Wastewater Containing Anionic Congo Red Dye

In this investigation, Zn/Al carbonate layered double hydroxide (ZAC-LDH) and its derived material on calcination were synthesized for removing the anionic azo dye Congo red (CR) from wastewater. Numerous factors were methodically investigated, including temperature, adsorbent dosage, pH, starting Dye Concentration (DC), and contact time. The CR elimination percentage dropped as the initial DC increased from 25 mg/L to 100 mg/L at 30 °C for uncalcined LDH, and from 97.96% to 89.25% for calcined LDH. The pH analysis indicates that the highest level of dye removal was recorded within the acidic pH range through the electrostatic attraction mechanism. The sorption kinetics analysis results demonstrated that the pseudo-second-order kinetic model exhibited a stronger fit to both uncalcined LDH and CZA-LDH, with the maximum correlation coefficient value. The Van’t Hoff plots indicate the spontaneous nature of the physisorption process with a negative ΔG° (<−20 kJ/mol), while the endothermic adsorption process exhibited a positive ΔH°. The X-ray diffraction of calcined LDH reveals a significant intercalation of CR dye molecules, both prior to and following adsorption, showcasing a distinctive memory effect. The Brunauer–Emmett–Teller (BET) gas sorption measurements were performed to support the mesoporous nature of ZAC-LDH and CZA-LDH. The FTIR spectrum confirms the interaction of dye molecules on the surface of uncalcined and calcined LDH. These findings emphasize the efficacy of both the synthesized LDHs in removing CR dye, with CZA-LDH demonstrating superior efficiency compared to uncalcined LDH in the context of CR removal from wastewater.

Optimal decay rates for nonlinear Moore–Gibson–Thompson equation with memory and Neumann boundary

We consider the initial value problem of Moore–Gibson–Thompson equation with memory effect, being subject to the Neumann boundary condition. Here, the nonlinearity f is conservative and satisfies some polynomial growth conditions. Under the condition that g ( t ) decays exponentially, we obtain the uniform polynomial decaying rate of energy and the solution. Moreover, we show this decay rate is optimal in the sense that there exists a class of solutions decaying exactly at this rate.

Effect of IL-15 on anti-tumor immune response to radio-immunotherapy through systemic immune activation.

e14641 Background: In this study, we propose to investigate the key role of IL-15 in radio-immunotherapy and its mechanism in regulating systemic immune activation by radio-immunotherapy. And further explore the potential of IL-15 combined with radio-immunotherapy. Methods: LLC5 and MC38 cells were used in this study. Mouse model and co-culture model were constructed to analyze the effect of IL-15 after radio-immunotherapy. Anti-IL-15 antibody was used to clarify the role of IL-15 on radio-immunotherapy. Flow cytometry and multiplex immunofluorescence were used to clarify IL-15Rα lever in macrophage after radio-immunotherapy. The effect of IL-15 in tumor and secondary lymphoid organ(SLO) was observed after macrophage removal. Macrophage IL-15 level were tested by ELISA. Tumor growth, TME, and memory effect after IL-15 combined with radio-immunotherapy were observed. In co-culture model, CD8+ T cell function were tested. Clearance macrophage of mice to determine the role of macrophage in combination therapy. After macrophages co-cultured with tumor cells, cytokine microarray was used to analyze the cytokine secretion of macrophages in combination treatment. Results: IL-15 secretion was significantly upregulated in TME after radio-immunotherapy. IL-15 and IL-15Rα were most enriched on macrophages and IL-15Rα was significantly increased after radio-immunotherapy. IL-15 inhibition significantly attenuated tumor killing and systemic immune activation and resulted in decreased IL-15Rα expression on macrophages. Removal of macrophages resulted in a significant reduction of IL-15 in tumor and spleen. Radio-immunotherapy in the co-culture model induced a significant increase of IL-15 secreted by macrophages.IL-15 combined with radio-immunotherapy can significantly controlled tumor growth, stimulated systemic immune activation, and CD8+ T cells and memory T cells were significantly increased in the circulation of long-term survival mice. In co-culture experiments, combination treatment stimulated proliferation and secretion of IFN-γ+CD8+ T cells. And it stimulated macrophages secrete more chemokines, especially CCL5, recruit more CD8+ T cells aggregate around macrophages. Macrophage clearance and co-culture experiments confirm that the synergistic effect of this combination therapy is mainly dependent on macrophages. Conclusions: IL-15 plays a critical role in systemic immune activation induced by radio-immunotherapy. Macrophages are the main cellular site of IL-15 effect in the microenvironment of tumor and SLO after radio-immunotherapy. IL-15 combined with radio-immunotherapy had a synergistic antitumor effect, and this combination treatment induced a further enhancement of memory T-cell-mediated systemic immune activation. Macrophage-secreted chemokines such as CCL5 played an important role in the antitumor effect of this combination therapy strategy.

Effects of Zr and Hf on superelasticity, shape memory effect and microstructure of β-type (Ti–Zr–Hf)–Nb–Sn multi-principal element alloys with low magnetic susceptibility

(Ti–Zr–Hf)(97−x)–xNb–3Sn (Ti:(Zr + Hf) = 1:1) alloys were designed for biomedical superelastic alloys with magnetic resonance imaging (MRI) compatibility. The effects of Zr and Hf on constituent phases, superelasticity, shape memory effect and magnetic susceptibility were clarified. The specific Nb content for superelasticity and shape memory effect was also explored. It was found that the (Ti–Zr)–6.5Nb–3Sn alloy exhibited a superelastic recovery strain of 5.2 % with lower magnetic susceptibility compared to conventional Ti–Ni and Ti–Nb alloys. The magnetic susceptibility decreased with increasing Hf content. The (Ti–Hf)–9Nb–3Sn alloy showed a superelastic recovery strain of 0.9 % and very low magnetic susceptibility less than half of that of the conventional alloys. Based on the lattice parameters of these alloys, it was found that these alloys exhibited larger transformation lattice strain between a β phase and an α” phase than those of the Ti–Nb alloys, suggesting high potential to exhibit a large superelastic recovery strain. According to orientation analyses of constituting grains, the larger superelastic recovery strain in the (Ti–Zr)–6.5Nb–3Sn alloy than that of the (Ti–Hf)–9Nb–3Sn alloy is considered to be caused by a strong recrystallization texture of {001}β <110>β. By optimization of heat-treatment temperature, superelastic recovery strain of 3.6 % was achieved in the (Ti–0.5Zr–0.5Hf)–7.5Nb–3Sn alloy.

Crystal plasticity based constitutive model for deformation in metastable β titanium alloys

Due to attractive mechanical properties, metastable β titanium alloys have become very popular in many industries including aerospace, marine, biomedical, and many more. It is often the complex interplay among the different deformation mechanisms that produces many of the sought-after properties, such as enhanced ductility, super-elasticity, and shape memory effects. Stress induced martensitic transformation is an important deformation mechanism for these alloys. Understanding of it and the influence it has on the microstructural evolution of materials is of great importance. To this end we have developed a crystal plasticity based constitutive model which accounts for both martensitic phase transformation and slip based plasticity simultaneously in metastable β titanium alloys. We present a new formulation for the evolution of martensite transformation, based on physical principles and crystal plasticity theory. To understand and demonstrate this feature of the model, a parametric assessment of the newly developed constitutive model is conducted. This is followed by first of its kind analyses of stress induced martensitic transformation in metastable β titanium alloys. We firstly present validations against uniaxial loading experiments for different metastable β titanium alloys exhibiting stress induced martensite transformation. As part of this, single crystal simulations in metastable β titanium alloys are used for the first time to investigate the interaction of individual transformation systems during unconstrained transformation. This study shows good agreement between the experimental and simulated responses during all stages of deformation in which elastic, transformation and finally the slip stage are exhibited. Relatively ‘strong’ and ‘weak’ orientations for transformation are observed, consistent with experimental studies. The work done here demonstrates the ability of this crystal plasticity finite element method to capture physical mechanisms while bringing new insight about the interaction of different deformation mechanisms in metastable β titanium alloys.