Direct Current

In the present study, there was a significant improve- ment in mean scores of reaction behavior in both groups especially in group A. These results came in agreement with the opinion of Antal and colleagues [30] who re- ported that tDCS enhances cognitive functions. Hummel and colleagues [31] also reported that cognitive functions might be modulated more effectively by tDCS. Sparing and colleagues [32] stated that transcranial direct current stimulation tDCS with constant current of 2 mA can in- crease cortical excitability by polarization of the under- lying brain tissue and enhance cognitive function.

Material fracture toughness based on J-integral versus crack-extension relationship (J-R curve) is investigated with direct current potential drop (DCPD) technique and compared with results from elastic unloading compliance (EUC) or normalization technique. The test matrix covered four different materials, half inch thickness and one inch thickness compact tension (C(T))specimens, and temperatures ranging from 24 °C to 600 °C. The original J-R curves from DCPD yielded much smaller Jq value than EUC or normalization results due to the influence of plastic deformation on potential drop. To counter this effect, two new methods for adjusting DCPD data have been proposed. After adjustment, the average difference in Jq between DCPD and EUC or normalization results is only about 8% whereas the difference in tearing modulus is about 17%. The promising results prove the applicability of DCPD for J-R curve determination for C(T) specimens especially in extreme environments, such as elevated temperatures, where conventional EUC method faces considerable challenges.

Direct-current motors, as the name implies, use direct unidirectional current. DC motors are used in special applications where high torque starting or smooth acceleration over a broad speed range is required. The advantages of using these types of motors over conventionally used AC motors are stated below.

A anodal tDCS, ADDS arm dystonia disability scale, AMT active motor threshold, APP average pen pressure, BDI beck depression inventory, C cathodal tDCS, ICARS International Cooperative Ataxia Rating Scale, M1 motor cortex, mA milliampere, MCT Mechanical Counter Test, Min minutes, MEPs motor evoked potentials, MSF mean stroke frequency, Offline the subject receives stimulation before and after executing the task, Online the subject receives stimulation during the task, PDQ-8 Parkinson ’ s disease questionnaire 8, Fp prefrontal areas, PSD power spectral density, S sham tDCS, SARA scale for the Assessment and Rating of Ataxia, SR Stretch reflexes, SRTT serial reaction time task, tCDCS transcranial cerebellar direct current stimulation, tCCDCS transcranial cerebello-cerebral direct current stimulation, tDCS transcranial direct current stimulation, TCRS tremor clinical rating scale, UPDRS Unified Parkinson’s disease rating scale, VAS visual analog scale, WCRS writer’s cramp rating scale, 9HPT Nine-Hole Peg Test, 8MW 8-Meter Walking Time

We report on a theoretical investigation of a direct current generation in carbon nanotubes (CNTs) that are stimulated axially by terahertz (THz) field. We consider the kinetic approach based on the semiclassical Boltzmann’s transport equation with constant relaxation time approximation, to- gether with the energy spectrum of an electron in the tight-binding approximation. Our results in- dicate that for strong THz-fields, there is simultaneous generation of DC current in the axial and circumferential directions of the CNTs, even at room temperature. We found that a THz-field can induce a negative conductivity in the CNTs that leads to the THz field induced DC current. For va- rying amplitude of the THz-field, the current density decreases rapidly and modulates around zero with interval of negative conductivity. The interval decreases with increasing the amplitude of the THz-field. We show that the THz-field can cause fast switching from a zero DC current to a finite DC current due to the quasi-ballistic transport, and that electron scattering is a necessary condition for switching.

An empirical equation (equation (2)) has been derived for predicting the direct current interruption of a convoluted arc device which incorporates the effects of the applied B-field, a parallel RLC circuit and, indirectly, PTFE ablation of the B-field coil containing current cylinder. This equation predicts that the current interruption is independent of the initial quasi- steady current, increases with the magnitude of the B-field and that the present RLC circuit doubled the current level interrupted. Although the empirical equation reasonably predicts current interruption for the present operating conditions, further evaluation is of course desirable.

The field of transcranial direct current stimulation (tDCS) has experienced significant growth in the past 15 years which is mainly devoted to determining the basic and clinical potential of tDCS in humans. The aim of this study is to quantitatively analyze the current worldwide progress on tDCS research as well as to highlight researchers, journals, institutions and countries which are contributing significantly in the past 18 years. We conducted a quantitative analysis of research articles regarding tDCS published from 1998 to 2016 and indexed in the web of science core collection database. Data was downloaded in October, 2016. In the past 18 years, there were 2457 studies on tDCS indexed by web of science database, including all documents type such as article, review, meeting abstract, proceedings paper, letters, and etc. This study is focusing on the main articles and reviews; therefore, the research production was reduced to 2000 publications. The analysis showed that most of the studies in the field were published by North American and European institutions with a reasonable proportion of the publications were also by Japanese institutions from Asia. From the perspective of research progress, we found that the number of published papers on tDCS has increased significantly in the past 10 years, between them a remarkable positive correlation exists.

The present review collects the most relevant empirical evidence available in the lit‑ erature until date regarding the effects of transcranial direct current stimulation (tDCS) on the human motor function. tDCS in a non‑invasive neurostimulation technique that delivers a weak current through the brain scalp altering the cortical excitability on the target brain area. The electrical current modulates the resting membrane potential of a variety of neuronal population (as pyramidal and gabaergic neurons); raising or dropping the firing rate up or down, depending on the nature of the electrode and the applied intensity. These local changes additionally have shown long‑lasting effects, evi‑ denced by its promotion of the brain‑derived neurotrophic factor. Due to its easy and safe application and its neuromodulatory effects, tDCS has attracted a big attention in the motor neurorehabilitation field among the last years. Therefore, the present manu‑ script updates the knowledge available about the main concept of tDCS, its practical use, safety considerations, and its underlying mechanisms of action. Moreover, we will focus on the empirical data obtained by studies regarding the application of tDCS on the motor function of healthy and clinical population, comprising motor deficiencies of a variety of pathologies as Parkinson’s disease, stroke, multiple sclerosis and cerebral palsy, among others. Finally, we will discuss the main current issues and future direc‑ tions of tDCS as a motor neurorehabilitation tool.

tDCS is being administered in the treatment of stroke in different parts of the world. However, few investigations/treatments do not cite it as effective. For instance, studies carried out with post-stroke aphasia and stroke patients did not demonstrate improvement of conditions of patients using tDCS [27-29]. On the other hand, many studies have signified employment of tDCS in the treatment of patients with different neurological disorders (Table 1). The difference in response to tDCS can be ascribed to severity of neurological disorders and differences in areas of the brain that were exposed to stimulation by tDCS [30]. Studies using tDCS promise its application for manipulation of emotions regulation and decision-making in humans [31]. However, further investigations particularly involving humans are required to understand and authenticate tDCS’s actions on the brain, its mechanisms, and the associated behavioral and cognitive impacts. Table 1. Using transcranial direct current stimulation for stroke rehabilitation

“ tDCS ” , and “ transcranial direct current stimulation ” . Only articles describing empirical studies written in English were included. Pre-selected articles were indepen- dently assessed by two authors for the inclusion criteria, which was as follows: the article described a clinical experiment or case report; the article abstract was publicly available; the study used tDCS; and anxiety-related beha- vior was a primary study outcome. After excluding dupli- cates, both authors categorized articles for further analysis. The process of selecting articles for inclusion in this review was performed in two stages. First, two indepen- dent reviewers screened the articles based on the title and selected only relevant articles. Second, the abstracts of relevant articles were assessed to verify that the inclusion criteria was met. After examining the titles and abstracts, a total of 11 articles were found to ful fi ll all the inclusion criteria. These articles were then fully examined and rele- vant information was extracted.

Abstract— Investigations are reported into the use of an electromagnetically convoluted arc, external to a magnetic field (B-field) producing coil, in combination with a parallel R, L, C resonant circuit for interrupting quasi-steady currents. In order to elucidate the complex interactions between the arc, B-field and R, L, C circuit, the B-field producing coil is energised independently from the current to be interrupted and the R, L, C circuit. Experimental results are presented for the time variation of the currents flowing through the arc gap, the B-field coil and the parallel L, C, R circuit, along with the voltage across the arc gap. An insight is gained into the role of various effects, which are produced by the complex interactions and which might be used to advantage for direct current interruption.

As windfarms are moving further offshore, their maintenance has to be supported by the new generation Service Operation Vessels (SOV) with Dynamic Positioning capabilities. For the SOV safe operations it is crucial that any hazardous scenario is properly controlled. Whilst international regulations require the implementation of Failure Modes and Effects Analysis (FMEA) for SOV power systems, FMEA has been criticised for not addressing properly failures in control systems. In this study, System-Theoretic Process Analysis (STPA) is employed for identifying the hazardous scenarios in terms of Unsafe Control Actions (UCAs) in Direct Current (DC) and DC with batteries power systems. Then the identified UCAs are ranked based on their risk. The results demonstrate that the number of hazardous scenarios derived by the STPA increases in a power system with batteries in comparison to a conventional DC power system, thus depicting higher complexity of this system. However, the increase in overall risk is small and within acceptable limits, whilst the risk reduces for a number of UCAs leading to Diesel Generator overload sub-hazard.

The brushless direct current (BLDC) permanent magnet motor was chosen to demonstrate the theories and practices behinds electric motors. These particular types of motors are known for their high durability due to simplicity in design, and high RPM capabilities. BLDC motors have both small and large applications. For example, in every computer there is a hard drive. A hard drive consists of spinning disk that is powered by a small BLDC motor to rotate the hard drive disks at very fast speeds [2]. On the other hand with the newly developed hybrid cars coming out along with a small fuel efficient engine there are typically two or even four BLDC motors located on either the axel or each individual wheel [3]. Both of these motors are similar to this design in that they both run off of permanent magnets. This particular design is in between these two extreme (small, large) types of motors. The design although simple has been made extremely difficult when all aspects of a motor were to be taken into account and designed from scratch. The goal is a twelve volt, quarter horsepower design.

Abstract: This study presents a novel concept for a distributed current optical sensing network, suitable for protection and fault location applications in high-voltage multi-terminal direct current (HV-MTDC) networks. By utilising hybrid fibre Bragg grating- based voltage and current sensors, a network of current measuring devices can be realised which can be installed on an HV- MTDC network. Such distributed optical sensing network forms a basis for the proposed ‘single-ended differential protection’ scheme. The sensing network is also a very powerful tool to implement a travelling-wave-based fault locator on hybrid transmission lines, including multiple segments of cables and overhead lines. The proposed approach facilitates a unique technical solution for both fast and discriminative DC protection, and accurate fault location, and thus, could significantly accelerate the practical feasibility of HV-MTDC grids. Transient simulation-based studies presented in the paper demonstrate that by adopting such sensing technology, stability, sensitivity, speed of operation and accuracy of the proposed (and potentially others) protection and fault location schemes can be enhanced. Finally, the practical feasibility and performance of the current optical sensing system has been assessed through hardware-in-the-loop testing.

TDCS, the Transcranial Direct Current Stimulation is a non-invasive, painless brain stimulation treatment. It was originally developed to help patients who suffer from brain injuries or psychiatric conditions like major depressive disorder. We made advance tDCS device that can pass a little amount of current ranging between 0.1-2.5 mA at a voltage range ±0.064 voltage within the brain scalps as well as store the stimulation data in real time. In this device, we introduced a flexible headband which can easily fit everyone’s head. This headband consists of two electrodes by which current is passed through the brain. We have developed an android application to control the current flow of the device smartly. It can be add new dimension in neurostimulation process.

Abstract—Electrical transmission networks are becoming increasingly interconnected, on continental scales, toward secure and cost-effective supplies of electrical energy met by growing adoption of low-carbon generation. High voltage direct current transmission links employ power electronics to enable this interconnection, of which conventional designs require high- frequency distortion to be filtered by dedicated assets including resistors, reactors, and capacitor banks. These assets are tuned to select for characteristic harmonic frequencies, but operating conditions (firing angle and commutation overlap) also influence high frequency signal composition. This paper presents simulations of these filtering assets to illustrate high frequency signal attenuation, considering the effects of varied operating conditions, filter bank switching, and component degradation.

Objective: Cathodal transcranial direct current stimulation (tDCS) is a focal neuromodulation technique that suppresses cortical excitability by low-ampli- tude constant electrical current, and may have an antiepileptic effect. Yet, tDCS has not been tested in status epilepticus (SE). Furthermore, a combined tDCS and pharmacotherapy antiseizure approach is unexplored. We therefore exam- ined in the rat pentylenetetrazol (PTZ) SE model whether cathodal tDCS (1) suppresses seizures, (2) augments lorazepam (LZP) efficacy, and (3) enhances GABAergic cortical inhibition. Methods: Experiment 1 aimed to identify an effective cathodal tDCS intensity. Rats received intraperitoneal PTZ followed by tDCS (sham, cathodal 1 mA, or cathodal 0.1 mA; for 20 min), and then a sec- ond PTZ challenge. In Experiment 2, two additional animal groups received a subtherapeutic LZP dose after PTZ, and then verum or sham tDCS. Clinical and electroencephalography (EEG) epileptic activity were compared between all groups. In Experiment 3, we measured GABA-mediated paired-pulse inhibition of the motor evoked potential by paired-pulse transcranial magnetic stimula- tion (ppTMS) in rats that received PTZ or saline, and either verum or sham tDCS. Results: Cathodal 1 mA tDCS (1) reduced EEG spike bursts, and sup- pressed clinical seizures after the second PTZ challenge, (2) in combination with LZP was more effective in seizure suppression and improved the clinical seizure outcomes compared to either tDCS or LZP alone, and (3) prevented the loss of ppTMS motor cortex inhibition that accompanied PTZ injection. Interpretation: These results suggest that cathodal 1 mA tDCS alone and in combination with LZP can suppress seizures by augmenting GABAergic cortical inhibition.

Introduction: Neurocognitive impairments have been observed in patients with bipolar disorder (BD) even during the euthymic phase of the disease, potentially representing trait- associated rather than state-associated characteristics of the disorder. In the present study, we used transcranial direct current stimulation (tDCS) applied to cerebellar and prefrontal cortices to improve the neurophysiological performances of patients with euthymic BD.

Direct current (DC) motors have variable characteristics and are used extensively in variable-speed drives. DC motor can provide a high starting torque and it is also possible to obtain speed control over wide range. To achieve that, the implementation of speed controller is a must. It is important to use an intelligent controller to control DC motor in desired speed. For this project, the implementation of fuzzy logic controller in DC motor drive is the main objective.

the idea that current passes through the skull and changes the excitability of targeted brain areas (Bikson et al., 2012). Resting membrane potentials of local populations of neurons are modulated, impacting postsynaptic subthreshold membrane de/polarization and thus increasing or decreasing the likelihood that a stimulus of constant strength will cause the neurons to reach their activation threshold (Nitsche et al., 2003, 2008). The amount of current reaching cortical areas directly under tDCS electrodes is significant (Wagner et al., 2006, 2007) and tDCS has been successfully used to elicit functional changes in motor function, mood and language/cognitive function (Nitsche and Paulus, 2000; Brunoni et al., 2012). One 10-min session of anodal tDCS results in excitability shifts lasting greater than one hour (Nitsche and Paulus, 2001), with multiple sessions resulting in longer-lasting shifts (Fregni and Pascual-Leone, 2007).