Good Endurance Research Articles

Digital and analog resistive switching in Lu-doped piezoelectric [formula omitted] film

Recently, in the field of artificial intelligence, neuromorphic devices have received significant attention for building artificial neural networks. Nano-scale resistive random access memory (RRAM) is one of the emerging electrical components for neuromorphic computing. In the present study, the synaptic characteristics are investigated in the piezoelectric BiFe1−xLuxO3 (BFLO) and Bi1−xLuxFeO3 (BLFO) (x = 0.05) based RRAM devices in a vertical configuration. Both devices show bipolar resistive switching behavior with good endurance characteristics. However, analog switching with potentiation and depression response is observed in Ag/BFLO/FTO device. The change in resistance and leakage current flow across the device is explained by the space charge limiting current conduction mechanism with regard to thermally generated and injected charge carriers. Both films possess strong electro-mechanical response with the ferroelectric and ferro-elastic domain walls oriented along 710, 1090, and 1800 directions. The electro-mechanical response and resistive switching properties make the materials viable for sensing, energy harvesting, and non-volatile memory technology. Moreover, the BFLO-based synaptic device has potential application in neuromorphic computation.

Assessment of Cardiorespiratory Endurance in Obese College Students using Coopers 12 Min Run Test

Background: The ability of the cardiorespiratory system to supply oxygen to active skeletal muscles during prolonged sub-maximal exercise and the ability of the skeletal muscles to perform aerobic metabolism is known as Cardiorespiratory Endurance. The highest attainable rate of aerobic metabolism during the performance of dynamic work that exhausts the subject within 5–10 min is internationally accepted as an index of one's cardiorespiratory fitness and it is defined as VO2max. A popular test used for measuring cardiorespiratory endurance (VO2max) is Cooper’s 12 min run test. A good predictor for overall health and nutritional status is BMI. This study was conducted to assess the cardiorespiratory endurance in obese college students using coopers 12 min run test. Methods: A total of 100 college students were included who met the inclusion criteria. The students were told to do 12 min coopers run test after a 5 min of warm up. After the test, the distance was recorded. Result: The result shows that the cardiorespiratory endurance is reduced in obese college students. According to the data obtained, 51% of obese participants have good cardiorespiratory endurance and 30% and 19% have fair and poor respectively. Conclusion: This study concluded that the cardiorespiratory endurance is reduced in obese college students using Coopers 12 minute run test. Lower cardiorespiratory endurance has risk to develop cardiovascular diseases, hypertension, and other chronic diseases. So, to improve the endurance one should reduce the weight and start exercising regularly. Keywords: [Obese college students, cardiorespiratory endurance, VO2 max]

Feasibility of bolted connectors in hybrid FRP-steel structures

Due to the low weight and excellent durability of composite materials, Fibre Reinforced Polymer (FRP) decks mounted on steel superstructures are becoming increasingly common in engineering practice. Bolted joints are generally used to facilitate connections between an FRP deck and steel girders in road bridges. The connections are subjected to both high magnitude static forces as well as fatigue loading due to overpassing vehicles. With ever increasing traffic on both road and railway bridges, fatigue performance is of critical concern. Bolted FRP joints have been extensively researched in the past under static loading, but less is known about the fatigue and creep behaviour of such joints. Furthermore, little research exists on non-pultruded FRP profiles connected using bolted connections. Therefore, the objective of this research is to investigate connectors’ feasibility by means of static, fatigue and creep experiments on four different types of bolted joints comprising mechanical connectors and injection techniques. The study focuses on application in vacuum infused GFRP panels with integrated webs made of multi-directional laminates) connected to steel bridge superstructures. In addition, experimental results are used to validate Finite Element Analyses (FEA). Based on the obtained results, the novel injected steel-reinforced resin (iSRR) connector shows promising potential in hybrid steel-FRP bridges where good fatigue endurance of the connection, are required.

Bionate® nucleus disc replacement: bench testing comparing two different designs

BackgroundIntervertebral disc nucleus degeneration initiates a degenerative cascade and can induce chronic low back pain. Nucleus replacement aims to replace the nucleus while the annulus is still intact. Over time, several designs have been introduced, but the definitive solution continues to be elusive. Therefore, we aimed to create a new nucleus replacement that replicates intact intervertebral disc biomechanics, and thus has the potential for clinical applications.Materials and methodsTwo implants with an outer ring and one (D2) with an additional midline strut were compared. Static and fatigue tests were performed with an INSTRON 8874 following the American Society for Testing and Materials F2267-04, F2346-05, 2077-03, D2990-01, and WK4863. Implant stiffness was analyzed at 0–300 N, 500–2000 N, and 2000–6000 N and implant compression at 300 N, 1000 N, 2000 N, and 6000 N. Wear tests were performed following ISO 18192-1:2008 and 18192-2:2010. GNU Octave software was used to calculate movement angles and parameters. The statistical analysis package R was used with the Deducer user interface. Statistically significant differences between the two designs were analyzed with ANOVA, followed by a post hoc analysis.ResultsD1 had better behavior in unconfined compression tests, while D2 showed a “jump.” D2 deformed 1 mm more than D1. Sterilized implants were more rigid and deformed less. Both designs showed similar behavior under confined compression and when adding shear. A silicone annulus minimized differences between the designs. Wear under compression fatigue was negligible for D1 but permanent for D2. D1 suffered permanent height deformation but kept its width. D2 suffered less height loss than D1 but underwent a permanent width deformation. Both designs showed excellent responses to compression fatigue with no breaks, cracks, or delamination. At 10 million cycles, D2 showed 3-times higher wear than D1. D1 had better and more homogeneous behavior, and its wear was relatively low. It showed good mechanical endurance under dynamic loading conditions, with excellent response to axial compression fatigue loading without functional failure after long-term testing.ConclusionD1 performed better than D2. Further studies in cadaveric specimens, and eventually in a clinical setting, are recommended.Level of evidence 2c.

Intrinsic resistive switching in ultrathin SiOx memristors for neuromorphic inference accelerators

Two-dimensional (2D) materials are promising memristive materials owing to their outstanding physical properties, electrical tunability and fast switching capability. However, 2D layered materials generally require sophisticated deposition techniques at the expense of limited large-scale homogeneity and high growth temperatures. Furthermore, the variability and reliability of the 2D materials based memristor should be further improved. Here, we report an intrinsic memristor based on ultrathin 2D-like nonlayered amorphous SiOx which is derived from a native oxidation process at ambient temperature. Such 2D-like memristors demonstrate low switching variability (3.7 %), nanosecond switching speed (15 ns), good endurance (>106 cycles) and high retention (>103 s at 85 °C). We verified the resistive switching mechanism via in-depth X-ray photoemission spectroscopy (XPS) analysis at different resistance states and confirmed the oxygen vacancies movement under the electric field between the SnOx reservoir layer and the SiOx layer. Moreover, Simulation results for an MNIST image classifier based on the ultrathin SiOx memristor show a high recognition accuracy of ∼ 98 %, manifesting its potential for the practical implementation of nonlayered 2D-like materials based neural network inference accelerator.

A cross-sectional study of the scapular muscles’ endurance in young healthy smartphone addicts and smartphone non-addicts, using scapular muscle endurance test

Background: Mobile phones have become an indispensable part of our day-to-day lives. The increasing dependency of people on smartphones has led to smartphone addiction among people. Extended use of smartphones in awkward postures with neck bent and arms unsupported requires significant stability of the scapular muscles to produce distal hand movements. The scapular muscles are thus under constant tension to achieve stability while transferring forces and motions along the kinetic chain requiring good endurance in the long run. The present study was thus aimed to compare the scapular muscle endurance of smartphone addicts versus non - addicts. Methodology: Smartphone Addiction Scale - Short Version (SAS - SV) scores were used to categorize 242 subjects into two groups (121 subjects in each group); Group 1 - Smartphone Addicts and Group 2 - Smartphone Non - Addicts. Scapular muscles’ endurance was assessed for all the subjects using the Scapular Muscle Endurance test and the time duration was noted. Results: Independent t-test was used to test the statistical significance of Scapular Muscle Endurance in Group 1 and Group 2. The observed difference between Group 1 and Group 2 was 24.07 seconds (p-value = 0.000). Conclusion: The scapular muscle endurance was significantly reduced in smartphone addicts as compared to smartphone non - addicts.

Analysis of Sports Education Students Interest in Muhammadiyah University of Surakarta in Archery Sports

Archery, namely archery, is a static sport that requires good physical condition, including strength and endurance, especially in the upper body muscles. The purpose of the researchers was to find out how interested students are and how important sports are for students of Sports Education at the University of Muhammadiyah Surakarta. A sample is part of the number and characteristics possessed by that population. The study took samples on Sports Education students of Muhammadiyah University of Surakarta semester 1 which totaled 89. Based on the results and discussion of the data obtained, researchers can draw conclusions about the interest of Sports Education students of the University of Muhammadiyah Surakarta in archery, and that the interest of Sports Education students of the University of Muhammadiyah Surakarta in archery sports is low. It is proven that only 7.5% of Sports Education students of Muhammadiyah University of Surakarta chose to strongly agree. There are several indicators of the reasons why students of Sports Education at the University of Muhammadiyah Surakarta have a low interest in archery, namely in the question of the body to be healthy and fit, refresh the brain, and want to excel in archery sports 38.3 students of Sports Education of Muhammadiyah University of Surakarta choose to hesitate.

Exploring conductance modulation and implementation of convolutional neural network in Pt/ZnO/Al2O3/TaN memristors for brain-inspired computing

Oxide-based memristors have emerged as a promising electronic device for high-density memory and neuromorphic applications. In our study, we explored the tunable analog switching and biological synaptic functions of a Pt/ZnO/Al2O3/TaN memristive device. Using transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS), we confirmed the presence of a TaOxNy interface layer at the anode contact, believed to play a critical role in resistance transitions. The memristive device showed excellent performance, including a stable and reproducible analog switching memory with a low operating voltage (μ=̶2.0/+1.7V), good cycling endurance (2 × 102), a high on/off ratio (>103), and retention up to 104 s at 85 °C. Additionally, multi-state resistances were achieved by varying the reset voltage, enabling the creation of neuromorphic synapses and high-density memories. Direct-current mode set and reset transitions showed multi-state resistance changes similar to potentiation and depression behaviors in biological synapses. Further simulations, including long-term potentiation (LTP) and long-term depression (LTD), paired pulse facilitation (PPF), and convolutional neural network (CNN) simulations for handwritten digits, showed an accuracy of 86.5%. These results indicate that the memristive device is highly suitable for use in high-density memory and brain-inspired computer systems.

Characteristics of Hf0.5Zr0.5O2 Thin Films Prepared by Direct and Remote Plasma Atomic Layer Deposition for Application to Ferroelectric Memory.

Hf0.5Zr0.5O2 (HZO) thin film exhibits ferroelectric properties and is presumed to be suitable for use in next-generation memory devices because of its compatibility with the complementary metal-oxide-semiconductor (CMOS) process. This study examined the physical and electrical properties of HZO thin films deposited by two plasma-enhanced atomic layer deposition (PEALD) methods- direct plasma atomic layer deposition (DPALD) and remote plasma atomic layer deposition (RPALD)-and the effects of plasma application on the properties of HZO thin films. The initial conditions for HZO thin film deposition, depending on the RPALD deposition temperature, were established based on previous research on HZO thin films deposited by the DPALD method. The results show that as the measurement temperature increases, the electric properties of DPALD HZO quickly deteriorate; however, the RPALD HZO thin film exhibited excellent fatigue endurance at a measurement temperature of 60 °C or less. HZO thin films deposited by the DPALD and RPALD methods exhibited relatively good remanent polarization and fatigue endurance, respectively. These results confirm the applicability of the HZO thin films deposited by the RPALD method as ferroelectric memory devices.

Analog Resistive Switching and Artificial Synaptic Behavior of ITO/WOX/TaN Memristors

In this work, we fabricated an ITO/WOX/TaN memristor device by reactive sputtering to investigate resistive switching and conduct analog resistive switching to implement artificial synaptic devices. The device showed good pulse endurance (104 cycles), a high on/off ratio (>10), and long retention (>104 s) at room temperature. The conduction mechanism could be explained by Schottky emission conduction. Further, the resistive switching characteristics were performed by additional pulse-signal-based experiments for more practical operation. Lastly, the potentiation/depression characteristics were examined for 10 cycles. The results thus indicate that the WOX-based devices are appropriate candidates for synaptic devices as well as next-generation nonvolatile memory.

Investigation of resistive switching properties in acceptor-induced Sr(Fe,Ti)O3 thin film memristor

In this work, the amorphous SrFe0.1Ti0.9O3-δ (a-SFT10) thin film was prepared on FTO/Glass substrate by chemical solution deposition process and then annealed at 500 ℃. Step Profiler measurements and SEM images revealed that the thickness of the a-SFT10 film was around 300 nm. The a-SFT10 thin film was found to have a smooth surface but was not crystalline. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical states of the film. Fe2+ and Fe3+ coexist in a-SFT10, according to XPS results, with Fe3+ being the dominating state. The mixed valence state of iron ions may be related to oxygen vacancies. Current-voltage characteristics were conducted to study the electrical properties. The uniform switching voltages, high switch ratio and good endurance were obtained. The ratio of high and low resistance (RH/RL) is up to 103 under positive bias voltage. The physical mechanisms underlying resistance switching behaviors were also investigated. The results show that the Ohmic, space charge limited current and Schottky conduction mechanisms dominated in different voltage ranges of A-SFT10 films, respectively. The oxygen vacancies associated with the acceptor doping play a significant role in the current characteristic in Au/a-SFT10/FTO/Glass device. Our findings suggest that the device has potential applications in future resistive random access memory.

A novel Sr5BiTi3Nb7O30 tungsten bronze ceramic with high energy density and efficiency for dielectric capacitor applications

Dielectric capacitors with high capacitive energy storage are urgently needed to meet the growing demand for high-performance energy storage devices. Herein, a novel lead-free Sr5BiTi3Nb7O[Formula: see text] (SBTN) tungsten bronze relaxor ferroelectric ceramic is prepared and explored for potential energy storage applications. A high recoverable energy density [Formula: see text] ([Formula: see text] 3.72 J/cm3) and ultrahigh efficiency [Formula: see text] ([Formula: see text] 94.2%) at 380 kV/cm are achieved simultaneously. Both [Formula: see text] and [Formula: see text] exhibit superior stabilities against temperature (30–140[Formula: see text]C), cycles (100 –105) and frequency (1–500 Hz). In addition, a high current density of 796 A/cm2 and a large power density of 71.7 MW/cm3 are achieved, together with good thermal endurance and fatigue resistance. These results demonstrate that the obtained SBTN ceramic can be deemed as the promising candidates for dielectric capacitor applications.

Implementation of Endurance Training Model Based on Basic Soccer Techniques to Soccer Coaches in Pariaman City

Soccer is a game sport that requires good endurance skills. Good endurance will help players to be able to play optimally during the game. The selection of the right training model will encourage the creation of a structured and directed training process. Based on the results of interviews and observations in the field, there are findings that trainers still use the old or conventional training model. Lack of knowledge of trainers about training models can ultimately lead to the inability of trainers to create varied training programs. To overcome these problems, football coaches need to be given various training models. The approach methods used in solving partner problems are 1) Workshops in order to improve the understanding of trainers in preparing training programs, 2) Field practice to understand more deeply how to implement Drill-Based Endurance training models and 3) Follow-up discussions in the context of monitoring and evaluation. The result of this activity is an increase in the trainer's understanding and ability in training to increase endurance abilities.

Tuned band offset in homogenous TMDs via asymmetric ferroelectric semiconductor gates toward simultaneous rectification and memory

Band alignment engineering is crucial and feasible to enrich the functionalities of van der Waals heterojunctions (vdWHs) for rectifying functions in next-generation information storage technologies. However, band alignment tunability is volatile as it needs a sustained external field to maintain the Femi level of single components, which hinders the implementation of nonvolatile functions. Here, the ferroelectric semiconducting nature of alpha-In2Se3 is utilized to design vdWHs based on two-dimensional transition metal dichalcogenides (TMDs)/alpha-In2Se3, where TMDs are used as the channel, and the ferroelectric semiconductor alpha-In2Se3 is assembled as an asymmetric gate. A density functional theory validates that the band offset in a homogeneous TMDs channel is tuned by coupling the effect of the semiconducting nature and asymmetric ferroelectric gate of alpha-In2Se3, which induces simultaneous rectifying and memory functions. This includes a programmable rectifying ratio of up to 104, ultra-large memory window (110 V), programming/erasing of 104, and good endurance. The tuned band offset from the asymmetric ferroelectric semiconductor gate is conceptualized as a guideline to realize a simultaneous rectifying and memory device with high programmability.

Achieving excellent energy storage performances and eminent charging-discharging capability in donor (1-x)BT-x(BZN-Nb) relaxor ferroelectric ceramics

Prodigious efforts have been paid to explore excellent dielectric energy storage capacitors based on lead-free relaxor ferroelectric (RFE) ceramics in the last decades. However, there are rare candidates among them simultaneously possessing high energy storage density (Wrec), high efficiency (η), wide work temperature range and stable charge–discharge ability, etc. In this work, excellent energy storage performances are achieved in donor doped BaTiO3 (BT)-based RFE ceramics by adopting two effective strategies of domain engineering and defect engineering. By introducing Bi(Zn2/3-0.01xNb1/3+0.01x)O3+δ (BZN-Nb) into BT matrix, firstly, long-range ferroelectric polarization is broken to form polar nanoregions (PNRs) via domain engineering. Subsequently, Nb donor substitution results in a dramatic increase in bulk resistivity (ρb) accompanied by a significant increase in dielectric breakdown electric strength (EDBS) via defect engineering. Finally, a combination of relative high Pmax, much low Pr and giant EDBS ensures that the optimum composition x = 0.3 in (1-x)BT-x(BZN-Nb) system exhibits high Wrec of 5.96 J/cm3 and high η of 89.5 %. Such properties together with good thermal stability (up to 220 °C), good fatigue endurance (for 106 cycles) and eminent charging-discharging capability (e.g., discharge time t0.9 ∼ 50 ns, current density CD ∼ 1.17 kA/cm2 and power density PD ∼ 175.38 MW/cm3 at 300 kV/cm) suggest that the 0.7BT-0.3(BZN-Nb) ceramic is a very promising candidate among lead-free dielectric capacitors for energy storage applications.

Realization of Artificial Nerve Synapses Based on Biological Threshold Resistive Random Access Memory.

A one-selector one resistor (1S1R) array formed of a selector and resistive random access memory (RRAM) is an important way to achieve high-density storage and neuromorphic computing. However, the low durability and poor consistency of the selector limit its practical application. The fabrication of a selector based on egg albumen (EA) is reported in this paper. The device exhibits excellent bidirectional threshold switching characteristics, including a low leakage current (10-7 A), a high ON/OFF current ratio (106 ), and good endurance (>700days). It is used as a selector to form a 1S1R unit in combination with an EA-based RRAM to effectively solve the leakage current in a crossbar array. A feasible solution is provided for the realization of a protein-based 1S1R array to achieve high-density storage. The 1S1R unit shows characteristics similar to those of synapses in the human brain under impulse excitation and has great potential in simulating the human brain for neuromorphic calculations.).

Achieving adjustable digital-to-analog conversion in memristors with embedded Cs2AgSbBr6 nanoparticles.

In this work, the proportions of Cs2AgSbBr6 nanoparticles (NPs) mixed in a PMMA film are adjusted to the digital and analog types of resistive switching (RS) behaviors in Ag/PMMA&Cs2AgSbBr6-NPs/ITO memristor devices. It is confirmed that when the concentration of NPs doped in the PMMA film is about 5 wt%, the memristor devices demonstrate bipolar digital RS behaviors with excellent electrical characteristics such as low operating voltage, high ON/OFF ratio (>500), good endurance (>800 cycles), and stable retention ability (>104 s). However, the devices showed a transition to analog-type memristive behavior when the concentration of NPs doped in the PMMA film is around 10 wt%, and several artificial synapse behaviors are successfully simulated. The device model simulation is also used to explore the effect of the NPs on the local electric field and growing filaments. Our work provides an opportunity to explore next-generation artificial synapse devices based on lead-free halide perovskites.

Estimation of genetic parameters for production, reproduction, and growth curve of Fars indigenous chicken.

Iranian native chicken, including Fars indigenous chicken, is an important genetic resource due to its adaptation to stressful environmental conditions, good endurance and resistance to disease. The aim of this research was to determine the genetic infrastructure of Fars indigenous chicken using several nonlinear functions. The dataset included body weight at hatch (BW1), body weight at the 8th week (BW8), body weight at the 12th week (BW12), weight at sexual maturity (WSM), age at sexual maturity (ASM), number of eggs in the first 12 weeks of laying period (EN), egg weight at the first day of laying (EW1), average egg weight at the 28thday of laying (EW28), and average egg weight at weeks 28, 30, and 32 of the laying period (AEW). Growth models were fitted using the NLIN procedure and WOMBAT software was used to predict variance components for the best fit model parameters. Results suggested three-parameter models, for example, Gompertz, fitted better to the data than others. The maturity weight (A), initial weight (B), and maturity rate (K) parameters in the Gompertz model were 1996.8 ± 6.63, 4.11 ± 0.03, and 0.021 ± 0.0001, respectively. The heritability of A, B, and K parameters were 0.03, 0.05, and 0.12, respectively.

Resistive Switching Characteristics of HfO x -Based Memristor by Inserting GeTe Layer

In this study, by inserting a GeTe layer as the current suppression layer and the heating layer, we improved the forming yield (~91%), memory window (> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{3}}$ </tex-math></inline-formula> ), and resistive switching uniformity of HfOx-based memristor. Two forming polarities including positive forming (PF) bias and negative forming (NF) bias were applied to study resistive switching characteristics. After the PF process, the device shows unstable and volatile behavior that is related to ovonic threshold switching (OTS) characteristic. Negative differential resistance (NDR) phenomenon was observed during the NF process. In addition, the device exhibits nonvolatile characteristic, multilevel resistive switching, and good endurance (> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{5}}$ </tex-math></inline-formula> ) after the NF process. We also proposed a corresponding physical model to explain two resistive switching characteristics of the NF and PF processes.

Ultrahigh overall-performance phase-change memory by yttrium dragging

Benefiting from the dragging effect of yttrium, an ultrahigh overall-performance phase-change memory is reported, including low resistance drift, high data retention, low power consumption, fast operating speed, and good cycling endurance.