Instantaneous Rise Research Articles

Gold nanorod-assisted near-infrared stimulation of bullfrog sciatic nerve.

Infrared neural stimulation (INS) is a new and developing approach for neural repair, with the advantages of being non-contact, spatially precise, and artifact-free. However, the disadvantage of infrared light is that it is difficult to stimulate deep tissue because of its weak penetrating power. Therefore, this paper introduces an improved method using near-infrared laser to stimulate bullfrog sciatic nerves because of its strong penetrating power. Meanwhile, gold nanorods (Au NRs) are injected into the nerve to increase the absorption of light. The mechanism is the instantaneous temperature rise caused by the absorption of infrared light by Au NRs. The compound muscle action potential (CMAP) associated with the irradiated sciatic nerve is recorded by a multi-channel physiological signal instrument. The peak to peak amplitude (Vpp) of CMAP for sciatic nerves injected with Au NRs increases significantly compared to the CMAP for control nerves without Au NRs. These results demonstrate INS by labeling nerves with nanoparticle exhibiting latent capacity to increase the efficiency, spatial resolution, and the neural responsivity, and especially, can increase the penetration depth and reduce the requisite radiant exposure level.

Study on the Instantaneous Temperature and Life Prediction of Polymer Gear Based on ANSYS/LS-DYNA

T aking the polymer gear as the research object , analyzing the instantaneous temperature rise of the tooth surface in the polymer gear t hrough combined systematical approach of theoretical arithmetic and finite element analysi s . It is found that the loading torque , c o mpared to the rotational speed , has a more significant effect on the instantaneous temperature rise . Take the influence of the speed and the loading torque of the meshing polymer gear into full consideration , the life of the gear can be predicted. And its correctness also can be verified by experiments, w hich is of great theoretical value a nd has a promising prospect on engineering application.

Information leakage detection and protection of leaked information by using the MAC-IP binding technique

The Digital world is advancing in terms of technological development day by day, resulting in an instantaneous rise in Data. This massive amount of Data has introduced the thought of Big Data, which has attracted both the business and IT sectors leaving the scope for huge opportunities. In turn, securing this massive data has become a challenging issue in the field of Information and Communication Technology. In this paper, we have carried out the work on business information sharing data which contains some sensitive information to investigate the security challenges of data in the field of business communication. The article an attempt is also made to identify the user’s intention or behavior during the navigation of data. The greatest challenge that is associated here is to prevent the integrity of the data while sharing the data from organization to the third party, where there exist huge chances of data loss, leakages or alteration. This paper highlights the concepts of data leakage, the techniques to detect the data leakage and the process of protecting the leaked data based on encrypted form.

Human Stress Research Using Facial Thermal Imaging

Thermal imaging is one of the most promising methods of probing the psychological status of human beings because of its non-invasiveness. The paper focuses mainly on the understanding of fundamental properties of physiological responses to emotional stress and how they can be captured by using thermal imaging techniques. We study the facial image of stressed participants for correlating the thermal imprint and estimated stress marker. While the correlations between the thermal ROI and stress marker (cortisol level & heart beat rate) is not directly significant, facial thermal imprints are sensitive to the emotional stress and have potential to detect stress in real time. Unlike the startle induced instantaneous temperature rise, our experimental results further demonstrate that the temperature in the periorbital region does not increase during the Trier social stress test, but increases after the onset of emotional stress. Overall, the experimental results suggest that facial thermal imaging is a valuable method for the estimation of emotional stress.

An experimental investigation towards calibration of a shock tube and stagnation heat flux determination

This paper aims at comprehensive investigations towards design and installation of a moderate size shock tube (7 m long having an inner diameter of 55 mm, 20 mm thickness) and its experimental calibration through comparative parametric study. Necessary instrumentations are incorporated for measuring shock speeds and pressure rise across primary as well as reflected shock, obtained using nitrogen/helium as driver gas. The experimental evidence shows reasonable agreement between theoretical (one-dimensional shock tube relations) results. Further, an E-type coaxial surface junction thermocouple (CSJT) has been prepared in the laboratory and oil-bath calibration experiment gives its 'sensitivity'. Measurement of instantaneous surface temperature rise and subsequent stagnation heat flux are obtained using CSJT mounted on a specially-designed end-flange. The thermocouple noted a maximum rise of temperature of 7,800 K, marked as a characteristic constant of the sensor; since it is found to be independent of the magnitude of the step change in temperature.

The impact of the fast ion fluxes and thermal plasma loads on the design of the ITER fast ion loss detector

Thermal plasma loads to the ITER Fast Ion Loss Detector are studied for QDT = 10 burning plasma equilibrium using the 3D field line tracing. The simulations are performed for a FILD insertion 9–13 cm past the port plasma facing surface, optimized for fast ion measurements, and include the worst-case perturbation of the plasma boundary and the error in the magnetic reconstruction. The FILD head is exposed to superimposed time-averaged ELM heat load, static inter-ELM heat flux and plasma radiation. The study includes the estimate of the instantaneous temperature rise due to individual 0.6 MJ controlled ELMs. The maximum time-averaged surface heat load is ≲ 12 MW/m2 and will lead to increase of the FILD surface temperature well below the melting temperature of the materials considered here, for the FILD insertion time of 0.2 s. The worst-case instantaneous temperature rise during controlled 0.6 MJ ELMs is also significantly smaller than the melting temperature of e.g. Tungsten or Molybdenum, foreseen for the FILD housing.

Time resolved temperature measurement of polymer surface irradiated by mid-IR free electron laser

We have developed the time-resolved temperature measurement system by using a radiation thermometer FLIR SC620. Temporal temperature profiles of an acrylic resin surface by the irradiation of infrared free electron laser (FEL) pulse were recorded in an 8ms resolution to measure an instantaneous temperature rise and decay profile. Under the single-shot condition, a peak temperature defined as the temperature jump from the ambient temperature was found to be proportional to the absorbance. Under the multi-shot condition, the temperature accumulation was found to reach a roughly constant value where the supply and release of the heat is balanced.

Irradiation effects in beryllium exposed to high energy protons of the NuMI neutrino source

A beryllium primary vacuum-to-air beam ‘window’ of the "Neutrinos at the Main Injector" (NuMI) beamline at Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, USA, has been irradiated by 120 GeV protons over 7 years, with a maximum integrated fluence at the window centre of 2.06 1022 p/cm2 corresponding to a radiation damage level of 0.48 dpa. The proton beam is pulsed at 0.5 Hz leading to an instantaneous temperature rise of 40 °C per pulse. The window is cooled by natural convection and is estimated to operate at an average of around 50 °C. The microstructure of this irradiated material was investigated by SEM/EBSD and Atom Probe Tomography, and compared to that of unirradiated regions of the beam window and that of stock material of the same PF-60 grade.Microstructural investigations revealed a highly inhomogeneous distribution of impurity elements in both unirradiated and irradiated conditions. Impurities were mainly localised in precipitates, and as segregations at grain boundary and dislocation lines. Low levels of Fe, Cu, Ni, C and O were also found to be homogeneously distributed in the beryllium matrix. In the irradiated materials, up to 440 appm of Li, derived from transmutation of beryllium was homogeneously distributed in solution in the beryllium matrix.

Thermal and Electrochemical Modeling of Pouch Type LiFePO4 Batteries to Investigate Internal and Surface Temperature Change Considering the Effects of Number of Layers

Environmental concerns lead many researchers to develop alternative fuel sources to overcome problems such as carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides (NOx) and particulate matter emissions. Battery powered electric vehicles (BEV) are one of the strongest alternatives to replace fossil fuel based vehicles for being more environmentally friendly in terms of pollutant and greenhouse gas emissions [1]. Batteries containing olivine cathode materials (e.g. LiFePO4, aka LFP) are highly promising for electric vehicle (EV) applications due to their properties such as high gravimetric capacity, fast charging, and lower material and maintenance costs. However, certain properties of LFP batteries are still need to be improved for mass production. High temperature operation is one of the main concerns about BEVs since temperature of batteries increase during both charging and discharging as a result of thermochemical heating, joule heating and ambient temperature. Even though thermally stable materials are used for a battery, there is still a risk of explosion as a result of the localized high temperatures during operation [2]. It can be seen from the literature that most of the modeling studies tend to accept heat generation uniform for all cell components [3,4]. However, joule heating and electrochemical heating affect each layer differently. For instance, heat generation related to electrical heating (joule heating) varies proportional to the internal material resistances while heat generation related to electrochemical reactions (electrochemical heating) primarily affects solid-electrolyte interfaces (SEI) in lithium-ion battery systems [5]. Since instantaneous local temperature rise is the main risk factor for Li-ion battery related explosions, local heat generation behavior should be understood in order to develop a proper battery cooling mechanism for their utilization in battery powered electrical vehicles. Aim of this study is to create a thermal and electrochemical model for 20Ah commercial LiFePO4batteries to examine the heat generation in each battery layer as well as to study the time dependent heat distribution in the batteries. Battery models containing different number of cells are prepared with a finite element simulation software called COMSOL Multiphysics. Each cell having a copper negative current collector, graphite negative electrode, LiPF6 w/EC:DEC (1:1) electrolyte, LiFePO4positive electrode and aluminum current collector is modeled exactly the same with the purchased commercial 20Ah batteries. Then, heat generation at certain points and cross-sectional areas where temperature difference is expected to be high are examined. Heat generation behavior of selected points and layers are shown on 1D, 2D and 3D graphics for batteries composed of different number of layers. In order to verify the model results, charge-discharge tests are applied to 20Ah batteries that contain 30 layers and surface temperatures are measured for 6 different (3C, 2C, 1C, 0.7C, 0.5C, 0.2C) current rates. Measurements are compared to results obtained for the model having 30 layers. Each experiment is repeated for different ambient temperatures (-20, -10, 0, 10, 20, 30, 40, 50 °C) in a thermal chamber (POL-EKO Aparatura) to estimate the heat generation characteristics of LFP batteries under different environments. The project is believed to help improve efficiency of cooling mechanism development studies for Li-ion batteries. REFERENCES Notter D. A. et al. Environ. Sci. Technol., 44 (2010), 6550–6556Cho J. et al. Energy Environ. Sci., 4 (2011), 1621Cao B. et al. Journal of Power Sources, 195 (2010), 2393–2398Selman J.R. et al. Journal of Power Sources 83 (1999), 1–8 Wang C.Y. et al. Int. J. Energy Res., 34 (2010), 107–115

Study on the formation mechanism of saw-tooth chip in high-speed cutting process

The 080A15 and 30CrMnMo steels were cut by precision sawing machine. The microscopic characteristic of the chip surface and the chip failure microscopic mechanism have been studied. The studies show that the formation of saw-tooth chip is mainly a function of the strength and thermal conductivity. For 080A15 steel, the strength is low and the thermal conductivity is high, the plastic work was absorbed continuously by the process of plastic deformation, and the heat was dissipated at any moment. The heat energy did not reach the critical value causing thermal softening. The chip is more prone to ductile fracture. For 30CrMnMo steel, the bonding ability is stronger among atoms, and thermal conductivity is smaller. The plastic deformation is extremely fast and the instantaneous temperature rise was very high because the heat energy reached the critical value causing thermal softening. Therefore, the chip is more prone to adiabatic shear failure to form the saw-tooth chip divided uniformly by adiabatic shear band. The research results help to provide the basis for selecting materials with different adiabatic shearing sensitivities in the process of high-speed cutting by studying the energy barrier on the influence of chip failure mechanism.

Assessing impacts of sea level rise on seawater intrusion in a coastal aquifer with sloped shoreline boundary

This paper investigates the effect of gradual and instantaneous sea level rise (SLR) on the seawater intrusion (SWI) process in coastal aquifer systems with different levels of land-surface inundation. A set of hypothetical case studies with different shoreline slopes is used to conduct this numerical experiment. For the purpose of numerical modelling, a future rate of SLR from 2015 to 2100 is considered based on the moderate expectation of the Intergovernmental Panel on Climate Change (IPCC, 2001). The gradual SLR is implemented in two different stages. First, continuous and nonlinear rising of sea level is imposed starting from year 2015 up to the end of the century. After that the final value of sea level is maintained as constant in order to assess the response time spanning to a new steady state condition. The effects of pumping resulting in lowering of groundwater level are also considered together with the dynamic variation of sea level. The results show that the rate and the amount of SWI are considerably greater in aquifers with flat shoreline slopes compared with those with steep slopes. Moreover, a shorter period of time is required to reach a new steady state condition in systems with flatter slopes. The SWI process is followed by a significant depletion in quantity of freshwater resources at the end of the century. The situation is exacerbated with combined action of SLR and over-abstraction. Finally, by considering the effect of inundation of the shoreline due to gradual SLR, the sensitivity of the system to the main aquifer parameters including molecular diffusion of solute, dispersion, hydraulic conductivity and porosity is investigated.

The Research on Weak Fault Time Domain Feature Extraction of Diesel Engine Instantaneous Speed

Instantaneous speed signal is a new information source for diesel fault diagnosis. It has been used in critical fault diagnosis successfully such as misfire. But the occurrence rate of early weak diesel fault is high, and can’t be diagnosed easily by other information source, so it has high value to research on the weak fault feature extraction method of transient speed. Due to the difficulty in setting up effect and accurate mathematic model for diesel engine instantaneous speed under weak fault conditions, so in this paper the early fault simulated experiments are proceed in 6-135 type diesels. Many early faults are simulated by adjusting cylinder fuel eject quantity, adjusting exhaust valve clearance, simulating exhaust valve leak in differ degree. Through analyzing the variation rule of instantaneous speed signal in different status, the direct time domain fault feature is extracted. It is the instantaneous speed unitary rise amplitude ratio of every cylinder, the value of each cylinder is named as Pi. The experiments outcome shows that if Pi descend over 10%, then the No.i cylinder exist fault. The feature is very sensitive to some fault which influence gas press in cylinder such as fuel ejects quantity not uniformity and valve leaking.

Effects of approach-avoidance related motor behaviour on the startle response during emotional picture processing

Motivational states may be induced by affective foreground stimulation or via proprioceptive feedback by certain postures or body movements. In the present study, we addressed the question of an interaction between basic motor actions and the valence of visual stimuli in an affective modulation of startle paradigm: is the potentiation for aversive and the attenuation for pleasant stimuli more pronounced when the muscles for a congruent approach or avoidance action are activated? Thirty-four volunteers (20 female) watched emotional pictures on a computer screen while simultaneously contracting the flexor vs. extensor muscles of the upper arm. After 3–4s, an acoustic startle stimulus (105dB, binaural, instantaneous rise time) was presented via headphones. Arm movement interacted with picture valence: flexion, compared to extension, increased affective startle modulation (F=4.32, p<0.05). This result suggests integration and not simple summation of postural and body movement effects on startle reflexivity.

Dust Effect on Thermal Performance of Flat Plate Solar Collectors

The solar collectors were exposed to the ambient conditions and left without cleaning for three months in winter in Lanzhou. In this paper, the effect of dust accumulation on the instantaneous efficiency, stagnation temperature and temperature rise of flat plate solar collectors is analyzed. The efficiency of solar collectors with and without dust in steady-state condition is measured following the Chinese National Standard GB/T 4271. Beside this, the stagnation test is carried out. The results show that the optical efficiency decrease of 9.7% and the stagnation temperature decrease of 0.3 °C–7.2 °C over time in a solar collector exposed for three months without cleaning. Furthermore, daily test is conducted. The efficiency, dust shading coefficient, and temperature rise of solar collectors are calculated by using experimental data. In this experiment, the dust shading coefficient changes between 0.83 and 0.94 during the whole day, and it is lower at noon than in the morning and evening hours. The efficiency difference and the temperature rise difference between the solar collectors with and without dust also vary with the dust shading coefficient, the optical efficiency, total solar irradiance, and mass flow rate during the whole day.

Mechanical properties of boron-nitride nanotubes after intense femtosecond-laser excitation

A femtosecond-laser pulse constitutes an unconventional tool to manipulate solids and nanostructures, for it may excite materials in a transient nonthermal state with hot electrons and atoms close to their initial temperature. Here we study the Young’s modulus and the electronic band gap of a (5, 0) zigzag boron-nitride nanotube (BNNT) after an ultrashort laser pulse excitation using density functional theory, where the effect of a femtosecond-laser pulse is modelled by an instantaneous rise of the electronic temperature. At room temperature, before the laser pulse, we obtain a Young’s modulus of 763 GPa, which decreases with increasing electronic temperature. For the band gap we find a value of 2.26 eV at room temperature, which increases with increasing electronic temperature and equals 3.28 eV at 28 420 K. We note that conventional means decrease the band gap of BNNTs and that a femtosecond-laser pulse is, to the best of our knowledge, the first tool that increases it. For comparison, we also present results for a (9, 0) zigzag BNNT.

P-Type Nitrogen-Doped ZnO Nanostructures with Controlled Shape and Doping Level by Facile Microwave Synthesis

We report herein the development of a facile microwave irradiation (MWI) method for the synthesis of high-quality N-doped ZnO nanostructures with controlled morphology and doping level. We present two different approaches for the MWI-assisted synthesis of N-doped ZnO nanostructures. In the first approach, N-doping of Zn-poor ZnO prepared using zinc peroxide (ZnO2) as a precursor is carried out under MWI in the presence of urea as a nitrogen source and oleylamine (OAm) as a capping agent for the shape control of the resulting N-doped ZnO nanostructures. Our approach utilizes the MWI process for the decomposition of ZnO2, where the rapid transfer of energy directly to ZnO2 can cause an instantaneous internal temperature rise and, thus, the activation energy for the ZnO2 decomposition is essentially decreased as compared to the decomposition under conductive heating. In the second synthesis method, a one-step synthesis of N-doped ZnO nanostructures is achieved by the rapid decomposition of zinc acetate in a mixture of urea and OAm under MWI. We demonstrate, for the first time, that MWI decomposition of zinc acetate in a mixture of OAm and urea results in the formation of N-doped nanostructures with controlled shape and N-doping level. We report a direct correlation between the intensity of the Raman scattering bands in N-doped ZnO and the concentration of urea used in the synthesis. Electrochemical measurements demonstrate the successful synthesis of stable p-type N-doped ZnO nanostructures using the one-step MWI synthesis and, therefore, allow us to investigate, for the first time, the relationship between the doping level and morphology of the ZnO nanostructures. The results provide strong evidence for the control of the electrical behavior and the nanostructured shapes of ZnO nanoparticles using the facile MWI synthesis method developed in this work.

Hydrodynamic responses of a piezoelectric driven MEMS inkjet print-head

A high nozzle density, piezoelectric (PZT) driven inkjet print-head has been fabricated on silicon wafers using MEMS manufacturing process by our research team. To understand the performance of the print-head, numerical simulations and lumped element modeling (LEM) were conducted and the results show that the Helmholtz mode is the dominant resonance mode acting on the flow oscillations at the nozzle. The deflection of the thin piezoelectric membrane on the top of the narrow pressure chamber indicates that the actual speed of sound is slower than the intrinsic speed of sound in the fluid. The dynamic responses and also the magnitude of pressure rise at the pressure camber are affected by the ink's effective speed of sound. The results of LEM show that the hydraulic cross-talk through the common ink supply flow channel has an effect on the drop velocity when neighboring nozzles are fired simultaneously. The back flow through the restrictor results in the instantaneous pressure rise in the common ink supply channel that leads to the increases in the drop velocity. It shows that increasing the compliance in the common in supply channel is most effective to reduce the hydraulic crosstalk.

Polytwistane

Twistane, C10H16, is a classic D2-symmetric chiral hydrocarbon that has been studied for decades due to its fascinating stereochemical and thermodynamic properties. Here we propose and analyze in detail the contiguous linear extension of twistane with ethano (ethane-1,2-diyl) bridges to create a new chiral, C2-symmetric hydrocarbon nanotube called polytwistane. Polytwistane, (CH)n, has the same molecular formula as polyacetylene but is composed purely of C(sp(3))-H units, all of which are chemically equivalent. The polytwistane nanotube has the smallest inner diameter (2.6 Å) of hydrocarbons considered to date. A rigorous topological analysis of idealized polytwistane and a C236H242 prototype optimized by B3LYP density functional theory reveals that the polymer has a nonrepeating, alternating σ-helix, with an irrational periodicity parameter and an instantaneous rise (or lead) angle near 15 °. A theoretical analysis utilizing homodesmotic equations and explicit computations as high as CCSD(T)/cc-pVQZ yields the enthalpies of formation Delta(f)H(0)°(twistane) = -1.7 kcal mol(-1) and Delta(f)H(0)°(polytwistane) = +1.28 kcal (mol CH)(-1), demonstrating that the hypothetical formation of polytwistane from acetylene is highly exothermic. Hence, polytwistane is synthetically viable both on thermodynamic grounds and also because no obvious pathways exist for its rearrangement to lower-lying isomers. The present analysis should facilitate the preparation and characterization of this new chiral hydrocarbon nanotube.

Thermal runaway features of large format prismatic lithium ion battery using extended volume accelerating rate calorimetry

In this paper, the thermal runaway features of a 25 Ah large format prismatic lithium ion battery with Li(NixCoyMnz)O2 (NCM) cathode are evaluated using the extended volume-accelerating rate calorimetry (EV-ARC). 4 thermocouples are set at different positions of the battery. The temperature inside the battery is 870 °C or so, much higher than that outside the battery. The temperature difference is calculated from the recorded data. The temperature difference within the battery stays lower than 1 °C for 97% of the test period, while it rises to its highest, approximately 520 °C, when thermal runaway happens. The voltage of the battery is also measured during the test. It takes 15–40 s from the sharp drop of voltage to the instantaneous rise of temperature. Such a time interval is beneficial for early warning of the thermal runaway. Using a pulse charge/discharge profile, the internal resistance is derived from the quotient of the pulse voltage and the current during the ARC test. The internal resistance of the battery increases slowly from 20 mΩ to 60 mΩ before thermal runaway, while it rises to 370 mΩ when thermal runaway happens indicating the loss of the integrity of the separator or the battery swell.

Study of internal short in a Li-ion cell I. Test method development using infra-red imaging technique

A new controlled test method has been developed to simulate the occurrence of internal short in Li-ion cells. Two different internal short kinds namely aluminum shorting to anode and cathode shorting to anode has been studied with this test method at several states of charge. Infra-red imaging technique has been adopted to analyze the thermal propagation for both the short kinds. As a comparison, the most commonly adopted nail penetration test was also conducted and analyzed using IR-imaging. The instantaneous rise in temperature referred as temperature spike upon incurring internal short was able to be captured using the IR imaging for the anode–aluminum short kind and the magnitude of such temperature spike was found to be proportional to SOC of the cell.