Transient Input Research Articles

Dynamic hydrogen production from PV & wind direct electricity supply – Modeling and techno-economic assessment

Renewable hydrogen from water electrolysis could contribute to the defossilization of various energy intensive sectors but continues to suffer from unfavorable economics. Attention is being paid to the direct supply of renewable electricity to electrolyzers; in particular from photovoltaic (PV) and wind units, whose fixed remuneration period has expired. However, detailed analysis of such operating strategies via modeling and simulation of the dynamic behavior of alkaline electrolysis (AEL) and polymer electrolyte membrane electrolysis (PEMEL) is lacking. In this work, an electrolyzer model is developed for both AEL and PEMEL and analyzed for PV and wind power input data sets from the region of northwest Germany. It is shown that key performance indicators (KPI) such as hydrogen production efficiency, electricity utilization rate, product output and net production costs are highly reliant on the shape of transient power input signals as well as the electrolyzers ability to cope with them. PEMEL technology generally has higher electricity utilization rates than AEL, while AEL still achieves relatively large hydrogen production quantities due to its higher efficiency. Thus, the better operational flexibility of PEMEL cannot generally be considered advantageous in terms of hydrogen production quantities – the same applies for economics. The most competitive hydrogen production costs were 4.33 € per kg for the AEL technology with direct electricity supply from old wind farms, which no longer receive fixed remuneration.

Simulation analysis on handling stability of virtual prototype vehicle of wheeled vehicle

In this paper, the steering stability of the Wheeled vehicle is evaluated by the response parameters characterizing the movement characteristics of the Wheeled vehicle. The steering stability of the virtual prototype of the Wheeled vehicle is simulated and analyzed. The steady state slewing characteristics, transient steering characteristicsunder angular pulse input of steering wheeland steering portability response characteristics were investigated to obtain the pros and cons of each evaluation index of the Wheeled vehicle prototype. Then the strategies and suggestions for further optimization of the steering system model were proposed.

Practical method of obtaining different levels of seismic energy dissipation using viscous fluid protective system on bridges

In order to achieve an optimal stability performance during transient vibratory actions the damping method is used for the bridge structures. Conventional approach would dictate that a structure must inherently attenuate or dissipate the effects of transient inputs through a combination of strength, flexibility and deformity. The damping level is being at low values at a conventional elastic structure and hence the amount of dissipated energy during transient vibratory actions is also in very low value. In the event of an earthquake, conventional structures usually perform high deformations which when situated beyond their elastic limits can cause the collapse. In such cases most of the dissipated energy amount is absorbed by the structure through localized damage as it fails. The concept of supplemental dampers added to a structure assumes that most of the energy amount input to the structure from a transient vibratory action will be absorbed, not by the structure itself, but rather by supplemental damping elements. Properly implemented, an energy dissipation system can be able to simultaneously reduce both stress and deflection within the structure elements. The fluid viscous protective system concept is presented as an optimum energy dissipation solution for bridge structure types. The operation of these devices is on the hydro-static principle of fluid flow through orifices of a special diameter value. In this paper it is presented an innovative functional and constructive model of fluid viscous device based on a practical design method which allows the controlled operation regime regarding the viscous fluid flow inside the device cylinder being able to provide considerable resistant force levels to relative motions between a bridge structural frames where is mounted and achieving considerable amounts of seismic energy dissipation when an earthquake occurs. For the constructive method of fluid viscous system model is adopted a practical constructive method aiming the direct control on the circulated fluid flow rate so that the device response force should be considerably larger, acting for limiting the relative movement of the structural frames and without introducing additional stiffness to the structural system to which it is attached, due to the elasticity of the working fluid type used. It represents an innovative method because of the special design orifices for fluid flow rate control used which, depending on the specific diameter values, can provide device different response force values and implicitly different dissipated energy amount levels based on the characteristic represented by the resistant force variation law according to the piston stroke.

Facilitating the propagation of spiking activity in feedforward networks by including feedback.

Transient oscillations in network activity upon sensory stimulation have been reported in different sensory areas of the brain. These evoked oscillations are the generic response of networks of excitatory and inhibitory neurons (EI-networks) to a transient external input. Recently, it has been shown that this resonance property of EI-networks can be exploited for communication in modular neuronal networks by enabling the transmission of sequences of synchronous spike volleys ('pulse packets'), despite the sparse and weak connectivity between the modules. The condition for successful transmission is that the pulse packet (PP) intervals match the period of the modules' resonance frequency. Hence, the mechanism was termed communication through resonance (CTR). This mechanism has three severe constraints, though. First, it needs periodic trains of PPs, whereas single PPs fail to propagate. Second, the inter-PP interval needs to match the network resonance. Third, transmission is very slow, because in each module, the network resonance needs to build up over multiple oscillation cycles. Here, we show that, by adding appropriate feedback connections to the network, the CTR mechanism can be improved and the aforementioned constraints relaxed. Specifically, we show that adding feedback connections between two upstream modules, called the resonance pair, in an otherwise feedforward modular network can support successful propagation of a single PP throughout the entire network. The key condition for successful transmission is that the sum of the forward and backward delays in the resonance pair matches the resonance frequency of the network modules. The transmission is much faster, by more than a factor of two, than in the original CTR mechanism. Moreover, it distinctly lowers the threshold for successful communication by synchronous spiking in modular networks of weakly coupled networks. Thus, our results suggest a new functional role of bidirectional connectivity for the communication in cortical area networks.

Fast and accurate identification of thermal dynamics for precision motion control: Exploiting transient data and additional disturbance inputs

Thermally induced deformations are becoming increasingly important for the control performance of precision motion systems. The aim of this paper is to identify the underlying thermal dynamics in view of precision motion control. Identifying thermal systems is challenging due to strong transients, large time constants, excitation signal limitations, large environmental disturbances, and temperature dependent behavior. An approach for non-parametric identification is developed that is particularly suitable for thermal aspects in mechatronic systems. In particular (1) reduced experiment time is achieved by utilizing transient data in the identification procedure. (2) an approach is presented that exploits measured ambient air temperature fluctuations as additional inputs to the identification setup. (3) the non-parametric model, obtained through (1) and (2), is used as a basis for parameter estimation of a grey-box parametric model. The presented methods form a complete framework that facilitates the implementation of advanced control techniques and error compensation strategies by providing high-fidelity models, enabling increased accuracy and throughput in high precision motion control.

Signaling models for dopamine-dependent temporal contiguity in striatal synaptic plasticity.

Animals remember temporal links between their actions and subsequent rewards. We previously discovered a synaptic mechanism underlying such reward learning in D1 receptor (D1R)-expressing spiny projection neurons (D1 SPN) of the striatum. Dopamine (DA) bursts promote dendritic spine enlargement in a time window of only a few seconds after paired pre- and post-synaptic spiking (pre-post pairing), which is termed as reinforcement plasticity (RP). The previous study has also identified underlying signaling pathways; however, it still remains unclear how the signaling dynamics results in RP. In the present study, we first developed a computational model of signaling dynamics of D1 SPNs. The D1 RP model successfully reproduced experimentally observed protein kinase A (PKA) activity, including its critical time window. In this model, adenylate cyclase type 1 (AC1) in the spines/thin dendrites played a pivotal role as a coincidence detector against pre-post pairing and DA burst. In particular, pre-post pairing (Ca2+ signal) stimulated AC1 with a delay, and the Ca2+-stimulated AC1 was activated by the DA burst for the asymmetric time window. Moreover, the smallness of the spines/thin dendrites is crucial to the short time window for the PKA activity. We then developed a RP model for D2 SPNs, which also predicted the critical time window for RP that depended on the timing of pre-post pairing and phasic DA dip. AC1 worked for the coincidence detector in the D2 RP model as well. We further simulated the signaling pathway leading to Ca2+/calmodulin-dependent protein kinase II (CaMKII) activation and clarified the role of the downstream molecules of AC1 as the integrators that turn transient input signals into persistent spine enlargement. Finally, we discuss how such timing windows guide animals' reward learning.

Increase of moisture content in Mogao Grottoes from artificial sources based on numerical simulations

Abstract Moisture is a key factor that can lead to deterioration of cultural heritages in arid regions. The Mogao Grottoes at the center of the ancient Silk Road suffer from moisture problem due to a multiple natural water sources, including the nearby river and flood, underground water migration, and rainfall. However, contributions by artificial sources remain unclear, which range from irrigation to the sand control vegetation belts on the sand dunes, plus the green field in the tourist and administrative area. Here, we use numerical simulations to examine if and how much these artificial sources increase the moisture in and around the grottoes. A wide range of factors are considered including both liquid and vapor phases of water, both steady and transient scenarios, local climate, and inputs by different water/vapor values and wind speeds. The results show that the drip irrigation on the sand dunes has little influence, because of its far distance to the grottoes, limited irrigation water supply, and strong evaporation on the desert surface; however, a threating potential exists if the water amount becomes too large. The green field close to the east of the grottoes with flood irrigation can increase the soil water content of the grottoes rock by about 1.5%, and the water vapor concentration by about 45% under a gentle easterly wind. Rainfall also increases the water content, with fluctuation, on the cliff surface where the grottoes are located. To prevent the manmade moisture-related damages to the grottoes, it is necessary to control the size of the green field, to convert flood irrigation to drip irrigation, and to change the trees to desert shrubs. A shield system can be applied to the cliff surface to reduce the damage from rainfall.

Disentangling Costs of Persistent and Transient Technical Inefficiency and Input Misallocation: The Case of Norwegian Electricity Distribution Firms

Numerous studies have focused on estimating technical inefficiency in electricity distribution firms. However, most of these studies did not distinguish between persistent and transient technical inefficiency. Furthermore, almost none of the studies estimated the cost of input misallocation arising from non-optimal use of inputs. One reason is that the cost function (input distance function) typically used in the literature does not allow for the separation of technical inefficiency and allocative inefficiency. In this study, we estimate both the persistent and transient components of technical inefficiency and input misallocation of Norwegian electricity distribution firms, using panel data from 2000 to 2016. Our modeling and estimation strategy is to use a system approach, consisting of the production function and the first-order conditions of cost minimization. Input misallocation for each pair of inputs is modeled via the first-order conditions of cost minimization. We also estimate the costs of each component of technical inefficiency and input misallocation by deriving the cost function for a multi-output separable production technology. Our modeling and estimation strategy handles endogeneity of inputs. Finally, we allow for inclusion of determinants of persistent and transient technical inefficiency. Our results show that the costs of input misallocation of Norwegian electricity distribution firms are non-negligible.

Homeostatic Plasticity Shapes the Retinal Response to Photoreceptor Degeneration.

Homeostatic plasticity stabilizes input and activity levels during neural development, but whether it can restore connectivity and preserve circuit function during neurodegeneration is unknown. Photoreceptor degeneration is the most common cause of blindness in the industrialized world. Visual deficits are dominated by cone loss, which progresses slowly, leaving a window during which rewiring of second-order neurons (i.e., bipolar cells) could preserve function. Here we establish a transgenic model to induce cone degeneration with precise control and analyze bipolar cell responses and their effects on vision through anatomical reconstructions, invivo electrophysiology, and behavioral assays. In young retinas, we find that three bipolar cell types precisely restore input synapse numbers when 50% of cones degenerate but one does not. Of the three bipolar cell types that rewire, two contact new cones within stable dendritic territories, whereas one expands its dendrite arbors to reach new partners. In mature retinas, only one of four bipolar cell types rewires homeostatically. This steep decline in homeostatic plasticity is accompanied by reduced light responses of bipolar cells and deficits in visual behaviors. By contrast, light responses and behavioral performance are preserved when cones degenerate in young mice. Our results reveal unexpected cell type specificity and a steep maturational decline of homeostatic plasticity. The effect of homeostatic plasticity on functional outcomes identify it as a promising therapeutic target for retinal and other neurodegenerative diseases.

A new criterion for the evaluation of the velocity field for rainfall-runoff modelling using a shallow-water model

The aim of this work is to evaluate the accuracy of physically based models using the 2D Shallow Water Equations (SWE) for the simulation of rain-induced runoff. A key expectation of these models is to be able to reproduce properly both hydrograph at the outlet of the watershed and the associated velocity field within the spatial domain for a given rain event. However, this ability can be very challenging in mountainous environments, which include heterogeneous and high values of bottom slope and transient rain inputs. In this paper, we focused on both the error due to the numerical resolution of the SWE for low water depths runoff on steep slopes and that due to the physical representation of friction on the bottom for various water depth to roughness height ratios. Four test cases have been used, at different scales, to evaluate the model in comparison with experimental data. The first test case (from Kirstetter et al. (2015)) was a rain induced flow in a straight channel. It allows to evaluate the error made for the chosen numerical resolution of the SWE and its impact on the velocity distribution in the domain (metric scale). A criterion defining an acceptable numerical error has been proposed. A second test case (from Cea et al. (2014)), has been chosen for being also metric scaled and in the right range of the numerical error criterion. It allowed to evaluate the ability of a new friction law (adapted from Lawrence (1997)) to represent the measured velocity field in several inundation regimes at the metric scale. The third test case was a 40 m2 real plot studied by Tatard et al. (2008). On this test case, measured velocities have been compared with the simulated ones. Thanks to an infiltration source term added to the mass conservation equation, hydrographs at the outlet of the plot have been well reproduced, as well as the main part (including the highest values) of the measured velocities. In particular, the velocities are well represented when the criterion given in the first test case is satisfied. Finally, the model is applied to a real watershed with an area of 1 km2 on which hydrographs at the outlet have been successfully reproduced for two extreme rainy events (Le Bouteiller et al., 2015). It appeared that both physical and numerical error were low in the hydrographic network and that the local velocities are correctly reproduced there, unlike in the hillslopes where the velocities are not well reproduced even if the mass fluxes are correct.

Analysis of a Compact Squeeze Film Damper with Magneto Rheological Fluid

Rotor systems play vital role in many modern day machinery such as turbines, pumps, aeroengines, gyroscopes, to name a few. Due to unavoidable unbalance in the rotor systems, there are lateral and torsional vibrations. Ignoring these effects may cause the system serious damages, which sometimes lead to catastrophic failures. Vibration level in rotor systems is acceptable within a range. Focus in this work is to minimize the vibration level to the acceptable range. One of the ways vibration level can be minimised is by means of providing damping. To accomplish this task in this work a new concept squeeze film damper is made by electro discharge machining which is compact in configuration, is filled with magneto-rheological (MR) fluid and tested out on one support of a Jeffcott rotor. This compact squeeze film damper (SFD) produces damping in a compact volume of the device compared to a conventional SFD. MR fluid is a smart fluid, for which apparent viscosity changes with the application of external magnetic field. This compact damper with MR fluid provides the variable damping force, controlled by an external magnetic field. In this work, proportional controller has been used for providing the control feedback. This MR damper is seen to reduce vibrations in steady state and transient input to the Jeffcott rotor. Parametric study for important design parameters has been done with the help of the simulation model. These controlled dampers can be used for reducing vibrations under different operating conditions and also crossing critical speed.

Rear-Wheel Steering Control for Enhanced Steady-State and Transient Vehicle Handling Characteristics

This paper presents a rear-wheel steering (RWS) control algorithm to enhance the vehicle handling performance without prior knowledge of tire characteristics. A RWS system is a chassis control module that can effectively improve vehicle maneuverability and stability. Since the tire-road friction coefficient is difficult to obtain in real world application, the proposed RWS control algorithm is designed so that it can be implemented without any tire-road information. The proposed RWS control algorithm consists of steady-state and transient control inputs. The steady-state control input is proportional to the driver's steering input for achieving the desired yaw rate gain. The desired yaw rate gain is obtained through an offline optimization that is aimed to minimize the vehicle lateral velocity. The transient control input consists of feedforward and feedback control inputs. The feedforward input is designed to improve transient responses of the yaw rate. Computer simulation studies have shown that a trade-off relationship between overshoot and response time exists when the RWS control input is a sum of the steady-state and feedforward inputs. To compromise this conflict, a feedback input has been designed. The overshoot can be significantly reduced while the response time is slightly changed via the feedback input. The proposed algorithm has been investigated via computer simulations. The simulation has been conducted for step steer and sine with dwell scenarios under various road friction conditions. The performance of a RWS vehicle was evaluated using objective indices. Simulation results show that the proposed algorithm enhances vehicle handling performance.

Elevated sedimentary removal of Fe, Mn, and trace elements following a transient oxygenation event in the Eastern Gotland Basin, central Baltic Sea

Iron, manganese, and trace elements play an important role in the marine carbon cycle as they are limiting nutrients for marine primary productivity. Water column concentrations of these bio-essential elements are controlled by the balance between input and removal, with burial in marine sediments being the main sink. The efficiency of this burial sink is dependent on the redox state of the water column, with sediments underlying a sulphidic (euxinic) water column being the most efficient sinks for Fe, but also Mn and trace elements (Co, Cd, Ni, Mo, As, W, V, and U). Transient changes in ocean redox state can hence affect trace element burial, and correspondingly, the ocean’s trace element inventory, but the impact of transient oxygenation events on trace element cycling is currently not well understood.Here, we investigate the impact of a natural oxygenation event on trace element release and burial in sediments of the Eastern Gotland Basin (EGB), a sub-basin of the Baltic Sea. After being anoxic (<0.5 µM O2) for ∼10 years, the deep waters of the EGB experienced a natural oxygenation event (Major Baltic Inflow, MBI) in 2015. Following this oxygenation event, we deployed benthic chamber landers along a depth transect in the EGB in April 2016, 2017 and 2018. We complemented these in situ flux measurements with analyses of water column, solid phase and pore water chemistry. Overall, the event increased the benthic effluxes of dissolved trace elements, though particular responses were element-specific and were caused by different mechanisms. Enhanced fluxes of Cd and U were caused by oxidative remobilisation, while Ni showed little response to the inflow of oxygen. In contrast, enhanced release of Co, Mo, As, W, and V was caused by the enhanced transient input of Mn oxides into the sediment, whereas Fe oxides were of minor importance. Following the dissolution of the oxides in the sediment, Mn and W were nearly completely recycled back to the water column, while fractions of Fe, Co, Mo, As, and V were retained in the sediment. Our results suggest that transient oxygenation events in euxinic basins may decrease the water column inventory of certain trace elements (Fe, Co, Mo, As, and V), thus potentially affecting global marine primary productivity on longer timescales.

Modeling somatic computation with non-neural bioelectric networks

The field of basal cognition seeks to understand how adaptive, context-specific behavior occurs in non-neural biological systems. Embryogenesis and regeneration require plasticity in many tissue types to achieve structural and functional goals in diverse circumstances. Thus, advances in both evolutionary cell biology and regenerative medicine require an understanding of how non-neural tissues could process information. Neurons evolved from ancient cell types that used bioelectric signaling to perform computation. However, it has not been shown whether or how non-neural bioelectric cell networks can support computation. We generalize connectionist methods to non-neural tissue architectures, showing that a minimal non-neural Bio-Electric Network (BEN) model that utilizes the general principles of bioelectricity (electrodiffusion and gating) can compute. We characterize BEN behaviors ranging from elementary logic gates to pattern detectors, using both fixed and transient inputs to recapitulate various biological scenarios. We characterize the mechanisms of such networks using dynamical-systems and information-theory tools, demonstrating that logic can manifest in bidirectional, continuous, and relatively slow bioelectrical systems, complementing conventional neural-centric architectures. Our results reveal a variety of non-neural decision-making processes as manifestations of general cellular biophysical mechanisms and suggest novel bioengineering approaches to construct functional tissues for regenerative medicine and synthetic biology as well as new machine learning architectures.

On the transient thermal response of thin vapor chamber heat spreaders: Optimized design and fluid selection

Vapor chambers provide highly effective heat spreading to assist in the thermal management of electronic devices. Although there is a significant body of literature on vapor chambers, most prior research has focused on their steady-state response. In many applications, electronic devices generate inherently transient heat loads and, hence, it is critical to understand the transient thermal response of vapor chambers. We recently developed a semi-analytical transport model that was used to identify the key mechanisms that govern the thermal response of vapor chambers to transient heat inputs (Int. J. Heat Mass Trans. 136 (2019) 995–1005). The current study utilizes this understanding of the governing mechanisms to develop design guidelines for improving the performance of vapor chambers under transient operating conditions. Two key aspects of vapor chamber design are addressed in this study: first, a parametric optimization of the wall, wick, and vapor-core thicknesses; and second, the selection of the working fluid. A protocol is demonstrated for selecting these parameters given the external vapor chamber envelope dimensions and boundary conditions. The study helps provide a framework for designing vapor chambers subject to transient heat loads, and to differentiate such design from the practices followed traditionally for steady-state operation.

On analysis of inputs triggering large nonlinear neural responses Slow-fast dynamics in the Wendling neural mass model

Many applications in neuroscience, such as electrical and magnetic stimulation, can be modelled as short transient input to non-linear dynamical systems. In excitable systems, small input yields more or less linear responses, while for increasing stimulation strength large non-linear responses may show up suddenly. A challenging task is to determine the transition between the two different response types.In this work we consider such a transition between normal and pathological responses in a model of coupled Wendling neural masses as we encountered in a previous study. First, the different timescales of inhibition in this model allow a slow-fast analysis. This reveals two different dynamical regimes for the systems’ response. Second, the two response types are separated by a high-dimensional stable manifold of a saddle slow manifold. Large pathological responses appear if the fast subsystem escapes from this manifold to another attractor. The typical fast oscillations seen during the pathological responses are explained by the bifurcation diagram of the fast subsystem. Under normal conditions these oscillations are suppressed by slow inhibition. External stimulation temporarily releases the fast subsystem from this slow inhibition. The critical response can be formulated as a boundary value problem with one free parameter and can be used to study the dependency of the transition between the two response types upon the system parameters.

Integrated design of working fluid and organic Rankine cycle utilizing transient exhaust gases of heavy-duty vehicles

Heavy-duty vehicles waste a major part of their fuel energy in the exhaust gas. To recover energy from the exhaust gas, Organic Rankine Cycles are a promising technology. However, both, the Organic Rankine Cycle and its working fluid have to be tailored to the transient energy input by the exhaust gas. For this purpose, we developed the so-called 1-stage Continuous-Molecular Targeting - Computer-aided Molecular Design (1-stage CoMT-CAMD) method. 1-stage CoMT-CAMD integrates the design of novel working fluids as degree of freedom into the process optimization. However, so far, 1-stage CoMT-CAMD is limited to a nominal operating point. In this work, we enable the integrated design for transient heat sources by combining 1-stage CoMT-CAMD with aggregation techniques. Aggregation techniques allow us to represent the many operating points due to the transient heat source by a few aggregated operating points serving as input for the integrated design. A subsequent assessment of the identified working fluids ensures safety and environmental friendliness. The resulting algorithm is applied to the design of an Organic Rankine Cycle on heavy-duty vehicles using the VECTO long haul cycle to characterize the transient exhaust gas. For this case study, 6 aggregated operating points are sufficient to represent the transient exhaust gas accurately. The optimal identified working fluid is ethyl formate and increases the net power output by 30% compared to the commonly used working fluid ethanol.

Control of Supercritical Organic Rankine Cycle based Waste Heat Recovery System Using Conventional and Fuzzy Self-tuned PID Controllers

This research develops a supercritical organic Rankine cycle (ORC) based waste heat recovery (WHR) system for control system simulation. In supercritical ORC-WHR systems, the evaporator is a main contributor to the thermal inertia of the system, which is greatly affected by transient heat sources during operation. In order to capture the thermal inertia of the system and reduce the computation time in the simulation process, a fuzzy-based dynamic evaporator model was developed and integrated with other component models to provide a complete dynamic ORC-WHR model. This paper presents two control strategies for the ORC-WHR system: evaporator temperature control and expander output control, and two control algorithms: a conventional PID controller and a fuzzy-based self-tuning PID controller. The performances of the proposed controllers are tested for set point tracking and disturbance rejection ability in the presence of steady and transient thermal input conditions. The robustness of the proposed controllers is investigated with respect to various operating conditions. The results show that the fuzzy self-tuning PID controller outperformed the conventional PID controller in terms of set point tracking and disturbance rejection ability at all conditions encountered in the paper.

Fast Electrophysiological Mapping of Rat Cortical Motor Representation on a Time Scale of Minutes during Skin Stimulation

The topographic map of motor cortical representation, called the motor map, is not invariant, but can be altered by motor learning, neurological injury, and functional recovery from injury. Although much attention has been paid to short-term changes of the motor map, robust measures have not been established. The existing mapping methods are time-consuming, and the obtained maps are confounded by time preference. The purpose of this study was to examine the dynamics of the motor map on a timescale of minutes during transient somatosensory input by a fast motor mapping technique. We applied 32-channel micro-electrocorticographic electrode arrays to the rat sensorimotor cortex for cortical stimulation, and the topographic profile of motor thresholds in forelimb muscle was identified by fast motor mapping. Sequential motor maps were obtained every few minutes before, during, and just after skin stimulation to the dorsal forearm using a wool buff. During skin stimulation, the motor map expanded and the center of gravity of the map was shifted caudally. The expansion of the map persisted for at least a few minutes after the end of skin stimulation. Although the motor threshold of the hotspot was not changed, the area in which it was decreased appeared caudally to the hotspot, which may be in the somatosensory cortex. The present study demonstrated rapid enlargement of the forelimb motor map in the order of a few minutes induced by skin stimulation. This helps to understand the spatial dynamism of motor cortical representation that is modulated rapidly by somatosensory input.

A Study on the Development Direction of a Tire Using Objective Evaluation and Analysis Techniques

This study examines the characteristics of the steering stability performance of a vehicle with varying tire cornering stiffness. The vehicle and its front and rear tire models, which are the basis of simulation, were fabricated using SPMM and Flat Trac, respectively. Tire cornering stiffness of the front and rear wheels was modulated by changing the LKY, one of the scaling coefficients in the tire model. Steering stability performance evaluation is based on frequency response (ISO7401)[1] which can analyze the dynamic characteristics of the vehicle with varying steering input cycle and Steady State Speed (ISO4138)[2] which enables dynamic analysis of the vehicle with varying transient inputs. The results were analyzed by using measurement assessment factors with high correlation with actual stiffness evaluation. As a result of the evaluation, it was confirmed that the steering and stability performance of the vehicle increase when the cornering stiffness of the front wheel is increased and the cornering stiffness of the rear wheel is decreased, which has enabled us to identify the direction of development of real tires. It is expected that this study will be a starting point to improve the efficiency of the research and development to identify the cause of the decline of the running performance of the tires and the way to enhance it.