Threshold Energy Level Research Articles

An Analysis on the Possibility of Establishing a Threshold Energy Level for the Solar Flares on the Interactions of Hard X-Ray Beams and the Ionosphere

An Analysis on the Possibility of Establishing a Threshold Energy Level for the Solar Flares on the Interactions of Hard X-Ray Beams and the Ionosphere

On-Demand Charging Management Model and Its Optimization for Wireless Renewable Sensor Networks.

Nowadays, wireless energy transfer (WET) is a new strategy that has the potential to essentially resolve energy and lifespan issues in a wireless sensor network (WSN). We investigate the process of a wireless energy transfer-based wireless sensor network via a wireless mobile charging device (WMCD) and develop a periodic charging scheme to keep the network operative. This paper aims to reduce the overall system energy consumption and total distance traveled, and increase the ratio of charging device vacation time. We propose an energy renewable management system based on particle swarm optimization (ERMS-PSO) to achieve energy savings based on an investigation of the total energy consumption. In this new strategy, we introduce two sets of energies called emin (minimum energy level) and ethresh (threshold energy level). When the first node reaches the emin, it will inform the base station, which will calculate all nodes that fall under ethresh and send a WMCD to charge them in one cycle. These settled energy levels help to manage when a sensor node needs to be charged before reaching the general minimum energy in the node and will help the network to operate for a long time without failing. In contrast to previous schemes in which the wireless mobile charging device visited and charged all nodes for each cycle, in our strategy, the charging device should visit only a few nodes that use more energy than others. Mathematical outcomes demonstrate that our proposed strategy can considerably reduce the total energy consumption and distance traveled by the charging device and increase its vacation time ratio while retaining performance, and ERMS-PSO is more practical for real-world networks because it can keep the network operational with less complexity than other schemes.

Sensing and analysis of spectrum holes in ISM band using USRP testbed

The spectrum frequency in the wireless communication industry is getting great attention due to the internet of things (IoT) technology's growth. However, the radio spectrum's frequency band use is limited because the primary user for specific services can cause spectrum interference as multiple users use the same spectrum frequency. Meanwhile, at each spectrum frequency, the number of users and utilization time are distinct. These will create vacancies for spectrum frequency assigned to the primary user. A new alternative in using the cognitive radio (CR) spectrum is accessible to these vacancies. This paper analyzed the frequency spectrum in the industrial, scientific and medical (ISM) band and identified spectrum holes for transmission by the secondary users. This work employed a realistic approach by measuring the spectrum using Universal Software Radio Peripheral (USRP) devices. Thus, the spectrum holes in the frequency spectrum had distinguished by using an energy detection technique. In the energy detection technique, the threshold energy level is set and then compared with the energy detector output to identify the primary user's existence (PU). The result indicates that 0.61% of spectrum holes have been detected in the 2.43-2.44 GHz range. This range is sufficient for home appliances, radio frequency peripherals (RF), and bluetooth devices.

Dynamics of a hybrid vibro-impact oscillator: canonical formalism

Hybrid vibro-impact (HVI) oscillations is a strongly nonlinear dynamical regime that involves both linear oscillations and collisions under periodic, impulsive, or stochastic excitation. This regime arises in various engineering systems, such as mechanical components under tight rigid constraints, seismic-induced sloshing in partially-filled liquid storage tanks, and more. The adaptive nonlinearity of the HVI oscillator is used by the HVI-nonlinear energy sink as an effective vibration mitigation solution for broad energy and frequency range. Due to the extreme nonlinearity of this regime, traditional analytical methods are inapplicable for the description of its transient dynamics. In the current work, we model the HVI oscillator by a forced particle in a truncated quadratic potential well with infinite depth. The slow flow dynamics of the system in the vicinity of primary resonance is described by canonical transformation to action-angle (AA) variables and the corresponding reduced resonance manifold (RM). Two types of bifurcation are examined. The former is associated with transition between linear oscillations and the HVI-regime and vice versa, and the latter with reaching a chosen maximal transient energy level. The transition boundaries on the forcing parameters plane associated with both bifurcation types are obtained analytically. The maximal transient energy level obtained for any given set of forcing parameters is described analytically as well. The energy jumps associated with the bifurcation of type I and crossing the corresponding transition boundary are obtained. Two underlying dynamical mechanisms that govern the occurrence of bifurcations are identified. They correspond to two distinct scenarios: in the first scenario, the energy of the slow flow gradually reaches the threshold energy level and is thus referred to as the ”maximum” mechanism. The second, potentially more dangerous scenario, involves abrupt transitions of the system’s energy response from a relatively small value to the threshold energy level. This pattern is related to the passage of the slow-flow phase trajectory through the saddle point of the RM, and thus is referred to as the “saddle” mechanism. Both mechanisms are universal for systems that undergo escape from a potential well. All theoretical results are in complete agreement with full-scale numerical simulations.

Silk Nanocrack Origami for Controllable Random Lasers

AbstractThe ancient art of Origami started to evolve as a contemporary technological method for the realization of morphologically induced and unconventional advanced functional structures. Here, directional random lasers (RLs) that are formed by folding (i.e., ori) dye‐doped natural protein silk fibroin (SF) film as paper (i.e., kami) are demonstrated. The folding stress induces parallel nanocracks that simultaneously function as diffuse reflectors and laser light outcouplers at the boundaries of the optical gain medium. Random lasing is observed after a threshold energy level of 0.8 nJ µm−2 with an in‐plane divergence‐angle of 13°. Moreover, the central laser emission wavelength is tuned from 588.7 to 602.1 nm by controlling the adjacent nanocracks distance and additional laser emission directions are introduced by further folding SF at different in‐plane angles that induce rectangular and triangular geometries. More significantly, RL is fabricated via a quick, scalable, and environmentally friendly stress‐induced nanocracking process maintaining its mechanical and optical properties even after 10,000 times of bending test. Hence, this study introduces a novel form of biocompatible, biodegradable, and large‐area protein microlasers by using an unconventional laser fabrication approach.

STEEL SAMPLES WELDING DEFECTS DETECTION BY ESTIMATING ENERGY OF CLUSTERS OF ACOUSTIC EMISSION SIGNALS

Acoustic emission (AE) detection of 5005005 mm size St3 steel samples welding defects. The informative parameters of AE signals recorded during welding with inserts of titanium and aluminum inserted into the root of the weld are analyzed. AE-signals recording was performed by welding diagnostic unit with automatically changing “floating” selection threshold. For coordinates of defects estimation clustering was performed by digital form and AE signals parameters. A comparative analysis of the clustering results was performed for each cluster. In this case, the total count of AE signals, their energy, and threshold levels were set, which were determined in accordance with the proposed algorithm. The degree of danger of defects in the weld was monitored by exceeding AE signal energy threshold level. If the AE signal had a second energy peak and when it exceeds the energy selection thresholds, the weld was rejected. It was experimentally shown that the titanium insert was a dangerous defect when the threshold energy level was exceeded, which was detected both with a high total count of AE signals and with a small number of recorded signals. In accordance with the proposed method, when introducing an aluminum insert into the weld, the defect was not considered dangerous.

Load Balance: Energy Efficient Routing Protocol in Wireless Sensor Network

<p>Energy consumption is one of the major issue in Wireless Sensor Network (WSN) which reduces the lifetime of the network. In this developed work an Cluster based Energy Efficient Routing Protocol (CBEERP) , which is gathering the sensor hubs in the system into clusters, in this manner it productively decreased the flooding traffic during discover the routing. The proposed CBEERP will balance the Energy in the Group by using some second order nodes. The reinforcement High effective hubs replace the cluster head after the cluster reaches to its threshold energy level. This CBEERP will help the effectiveness and lifetime of the system.</p>

Coding and functional defect region prediction of placental protein in an embryo cell of first trimester using ANN approach

The protein coding and functional regions in DNA sequences has become an exciting task in bioinformatics. In particular, the coding region has a 3-base periodicity, which helps for exon identification. Many signal processing tools and techniques have been successfully applied to identify tasks, but still need to be improved in this direction. In our work, we employ ANN classifier to predict coding and functional region of proteinin human embryo cell protein in first trimester, and evaluate their performances according to the comparison energy levels of coding region. The obtained from the threshold energy level, results show that in a box plot finally predict the mutation.

Upside/Downside statistical mechanics of nonequilibrium Brownian motion. I. Distributions, moments, and correlation functions of a free particle.

Statistical properties of Brownian motion that arise by analyzing, separately, trajectories over which the system energy increases (upside) or decreases (downside) with respect to a threshold energy level are derived. This selective analysis is applied to examine transport properties of a nonequilibrium Brownian process that is coupled to multiple thermal sources characterized by different temperatures. Distributions, moments, and correlation functions of a free particle that occur during upside and downside events are investigated for energy activation and energy relaxation processes and also for positive and negative energy fluctuations from the average energy. The presented results are sufficiently general and can be applied without modification to the standard Brownian motion. This article focuses on the mathematical basis of this selective analysis. In subsequent articles in this series, we apply this general formalism to processes in which heat transfer between thermal reservoirs is mediated by activated rate processes that take place in a system bridging them.

Liquid jets produced by an immersed electrical explosion in round tubes

Liquid jets produced by an electrical explosion in water in round, centimeter-wide tubes are investigated experimentally and theoretically. Several jet flow patterns including sharp conical forms and annular forms are observed through high-speed photography. The general features of these patterns are presented and examined herein. It is found that the jet pattern is influenced mainly by the tube diameter, with narrow tubes producing conical jets and wide tubes producing annular jets. The jet maintains a nearly constant velocity, which increases with the explosion energy and decreases with the tube diameter and the standoff distance. A quasi-one-dimensional theoretical model that includes the bubble dynamics is proposed. With the model proposed herein, the effective explosion energy is calibrated first by matching the maximum bubble size. The results show that the confinement imposed by the tube tends to reduce the effective energy and that tubes with smaller diameters collect less effective energy. A theoretical analysis of the jet velocity indicates that the jet has to overcome a threshold energy level to obtain a constant velocity and that in narrower tubes, the jet velocity is amplified. The amplification factor, which is defined as the ratio of the actual jet velocity to the theoretical maximum bulk velocity, generally decreases with the tube diameter. It approaches unity when the jet is annular or blunt, indicating that the kinematic focusing effect with this type of jet is negligible. A parametric analysis of the calibrated explosion energy and the amplification factor provides a relation that comprehensively represents the experimental data. The relation is found to be different from those obtained in previous investigations, and the reasons for this difference are discussed.

Directed Rotational Motion of Birefringent Particles by Randomly Changing the Barrier Height at the Threshold in a Washboard Potential

This communication presents a simulation study of the directed rotational motion of a birefringent spherical particle trapped in optical tweezers with randomly varying ellipticity of a trapping light at the point of threshold. When noise is not applied, the potential barrier due to the linear component of the polarization is simulated to be sufficient to prevent directed rotation till a certain threshold value of ellipticity. Random variations to the ellipticity cause random variations in the barrier height, including instants when the barrier is lower than the threshold energy level. It is due to this that the particle exhibits directed rotational motion at ellipticity lower than the threshold value. We also examine the rotational velocity of the birefringent particle as a function of the extent of zero-mean random noise applied to the ellipticity.

Fracture Energy of Materials Exposed to Pulse Action

To study the process of brittle fracture, initiated by a microsecond range pulse action, we applied the magnetic pulse technique of controllable pressure pulse generation with pulse amplitude up to 2 GPa. The threshold energy level has been found, and related to a parameter specific of each material - energy accumulation time. With application of the thermodynamic approach, we develop and demonstrate the destruction criterion that allows us to define this material parameter. Following the results of experimental data and numerical simulation, we show how to describe the destruction process both for samples with crack-type macro defects, and defect-free samples. The study reveals the dependency of the surface energy from the load build-up and material properties when exposed to magnetic pulse action.

Effects of sonication energy on the dispersion of carbon nanotubes in a vinyl ester matrix and associated thermo-mechanical properties

In the present paper, we report a systematic examination of sonication energy and the subsequent dispersion condition of nanoparticles in a vinyl ester resin. The nanoparticles were multi-walled carbon nanotubes (MWCNTs) functionalized with carboxylic acid groups. Two nanoparticle concentrations of 0.25 and 0.5 wt% with a variety of sonication amplitudes and duration were considered. Elastic moduli were determined using a 3-point flexural method and a nanoindentation technique. Glass transition temperatures (Tg) were also evaluated by differential scanning calorimetry. The dispersion quality of MWCNTs was investigated by high-resolution scanning electron microscopy (HR-SEM). Results indicated that with both concentrations, there is a gradual increase in elastic modulus and Tg up to a certain sonication energy level beyond which both properties decreased. However, this threshold energy level varied with MWCNT concentration. For example, the threshold energy level was 60 kJ in case of 0.25 wt% while it was only 15 kJ with 0.5 wt% concentration. It was also observed that regardless of the level of threshold energy, enhancement in properties remained more or less the same. This suggests that there is interplay between particle concentration and sonication energy that dictates the dispersion condition and hence controls the nanocomposite properties. It is further evidenced by SEM studies that nanotubes undergo significant structural changes such as length reduction even at lower energies that eventually limits the threshold level.

A Mastercurve to predict annual ryegrass (Lolium rigidum) seed devitalisation when exposed to multiple single sided impacts

A strategy to control herbicide resistant weeds is to use an impact mill to devitalise weed seeds as they exit a combine harvester. To model the impact milling of weed seeds, the milling response was split into material and machine functions separating the effect of seed properties from mill design and operational parameters. The material function was determined by subjecting annual ryegrass seeds ( Lolium rigidum ) to multiple single sided impacts using a rotational impact tester. The number of impacts, impact speed and seed moisture content were varied. Seed devitalisation was measured by germinating seeds in soil bins in a controlled environment room. Seed devitalisation increased with the number of impacts, the impact speed and decreasing moisture content. Seed devitalisation did not depend on the order of an impact sequence when exposed to multiple impacts at three different speeds. A threshold minimum energy per impact of 0.3991 kJ kg −1 (equivalent to ∼ 28 m s −1 ) was observed, below which almost zero devitalisation occurred. A material function Mastercurve for devitalisation was developed using this threshold energy level and one other material parameter which described a seed's resistance to fracture. The Mastercurve was able to accurately predict ( r 2 = 0.94) devitalisation of annual ryegrass seeds (11.3% m.c.) by the number of impacts above the threshold speed and impact speed in any impact sequence. The Mastercurve presented will be able to be used in future studies with a machine function to design impact mills to mechanically devitalise annual ryegrass seeds. • Seed devitalisation increased with impact speed and number of impacts. • Seed devitalisation reduced with moisture content. • Mastercurve fit based on impact energy above minimum impact energy. • Minimum impact energy for seed devitalisation was 0.3991 kJ kg −1 or 28 m s −1 .

Do ictal EEG characteristics predict treatment outcomes in schizophrenic patients undergoing electroconvulsive therapy?

Objective: The aim of this study is to investigate the relationship between features of electroencephalography (EEG), including seizure time, energy threshold level and post-ictal suppression time, and clinical variables, including treatment outcomes and side-effects, among schizophrenia inpatients undergoing electroconvulsive therapy (ECT). Method: This is a naturalistic follow-up study on schizophrenia patients, diagnosed using DSM-IV-TR criteria, treated by a psychosis inpatient service. All participants completed the Brief Psychiatric Rating Scale (BPRS), the Global Assessment of Functioning (GAF) scale, the Frontal Assessment Battery (FAB) and a Data Collection Form. Assessments were made before treatment, during ECT and after treatment. Findings: Statistically significant improvements in both clinical and cognitive outcome were noted after ECT in all patients. Predictors of improvement were sought by evaluating electrophysiological variables measured at three time points (after the third, fifth and seventh ECT sessions). Logistic regression analysis showed that clinical outcome/improvement did not differ by seizure duration, threshold energy level or post-ictal suppression time. Discussion and conclusion: We found that ictal EEG parameters measured at several ECT sessions did not predict clinical recovery/outcomes. This may be because our centre defensively engages in “very specific patient selection” when ECT is contemplated. ECT does not cause short-term cognitive functional impairment and indeed improves cognition, because symptoms of the schizophrenic episode are alleviated.

Effect of the electron energy distribution on total energy loss with argon in inductively coupled plasmas

The total energy lost per electron-ion pair lost εT is investigated with the electron energy distribution function (EEDF). The EEDFs are measured at various argon powers in RF inductively coupled plasma, and the EEDFs show a depleted distribution (a discontinuity occurring at the minimum argon excitation threshold energy level) with the bulk temperature and the tail temperature. The total energy loss per electron-ion pair lost εT is calculated from a power balance model with the Maxwellian EEDFs and the depleted EEDFs and then compared with the measured εT from the floating probe. It is concluded that the small population of the depleted high energy electrons dramatically increases the collisional energy loss, and the calculated εT from the depleted EEDFs has a value that is similar to the measured εT.

Determination of Threshold Energy Level of Monopolar Defibrillation Pulses Using the Luo–Rudy Cardiomyocyte Model

The effect of defibrillation pulses of different waveforms on the Luo–Rudy cardiomyocyte model in the Cell Electrophysiology Simulation Environment (CESE) was comparatively tested. It was established that a half-sine pulse has the minimum threshold of cell excitation energy, while an exponential pulse exhibits the maximum threshold (22% increase in comparison with the half-sine pulse). The threshold energy of the trapezoidal pulse with sloped rising and falling (waveform of the first phase of bipolar pulse in imPulse AND-P automated external defibrillators at energy levels of 150 and 180 J) was only slightly (4%) higher than the threshold energy of the half-sine pulse. The threshold energy of truncated exponential pulses, which are widely used in modern defibrillators, exceeded the threshold energy of the half-sine pulse by 10-14% (depending on the decline value). These results obtained with the Luo–Rudy model differ significantly from the results obtained using the characteristic energy method with the Blair model.

Impact damage resistance of CFRP with nanoclay-filled epoxy matrix

The influence of nanoclay on the impact damage resistance of carbon fibre–epoxy composites has been investigated using the low-velocity impact and compression after impact (CAI) tests. The load–energy vs. time relations were analyzed to gain insight into the damage behaviours of the materials. The CFRPs containing organoclay brought about significant improvement in impact damage resistance and damage tolerance in the form of smaller damage area, higher residual strength and higher threshold energy level. The presence of nanoclay in the epoxy matrix induced the transition of failure mechanisms of CFRP laminates during the CAI test, from the brittle buckling mode to more ductile, multi-layer delamination mode. Addition of 3 wt% clay was shown to be an optimal content for the highest damage resistance.

Assessment of low-temperature embrittlement of asphalt binders using an acoustic emission approach

Thin films of paving grade asphalt binders moulded on granite substrates were stressed under rapid cooling and thermal restraint conditions at temperatures ranging from 15°C to -50°C. This temperature range encompasses typical pavement temperatures in colder climates. Differential thermal contraction between the granite substrates and asphalt binders induces progressively higher thermal stress levels in the binders as the temperature drops resulting in thermal crack formation, and the corresponding release of elastic energy in the form of transient stress waves. Using piezoelectric sensors (Digital Wave, Model B-1025), a four-channel acoustic emission (AE) system was used to record the acoustic emission activity during the binder/granite cooling process. It was observed that AE events of high energy clustered around a narrow temperature range. Assuming the cracking temperature (T CT ) to be the temperature at which the AE signal energy exceeds a pre-selected threshold energy level, this AE testing approach was found to be sensitive and repeatable for predicting cracking temperatures (T CT ) in four paving grade asphalt binders processed to two distinct ageing levels. The effect of binder type, ageing level and binder film thickness on cracking temperature is discussed. These AE-based T CT predictions showed strong correlations with predictions based on either the AASHTO TP1 or the MPIA protocols.

Mid-infrared Cr^2+:ZnSe random powder lasers

We report simple methods of laser active Cr2+:ZnSe powder fabrication with average grain sizes of either approximately 10 or approximately 1 microm without crystal growth stage. Pure, uniformly mixed ZnSe and CrSe powders annealed at 1000 masculineC for 3 days in a sealed evacuated (approximately 10(-4) Torr) quartz ampoule exhibited middle-infrared laser action at room temperature under 1.56 microm excitation of D(2) Raman shifted radiation of Nd:YAG laser. The output-input characteristic clearly demonstrated the threshold-like behavior of the output signal with the threshold energy level of 0.5 and 3 mJ in 2.9 mm spot for 10 and 1 microm grain sizes, respectively.