Suppression of the anti-symmetry channel in the conductance of telescoped double-wall nanotubes

The conductance of telescoped double-wall nanotubes (TDWNTs) composed of two armchair nanotubes ($(n_O, n_O)$ and $(n_O-5, n_O-5)$ with $n_O \geq 10$) is calculated using the Landauer formula and a tight binding model. The results are in good agreement with the conductance calculated analytical by replacing each single-wall nanotube with a ladder, as expressed by $(2e^2/h)(T_+ + T_-)$, where $T_+$ and $T_-$ are the transmission rates of the symmetry and anti-symmetry channels, respectively. Perfect transmission in both channels is possible in this TDWNT when $n_O=10$, while $T_-$ is considerably small in the other TDWNTs. $T_-$ is particularly low when either $n_O$ or $n_O-5$ is a multiple of three. In this case, a three body effect of covalent-like interlayer bonds plays a crucial role in determining the finite $T_-$. When $n_O$ is a multiple of five, the five-fold symmetry increases $T_-$, although this effect diminishes with increasing $n_O$.Comment: Owing to errors of the calculation code, the numerical data shown in Figures are incorrect. Nonetheless, the corrected numerical calculations do not change the essential results. See erratum, PHYSICAL REVIEW B 79, 199902 (2009). The responsibility for the errors lies completely with the first author (Ryo Tamura

Comparative Analysis on Traumatic Brain Injury Risk Due to Primary and Secondary Impacts in a Pedestrian Sideswipe Accident

A series of pedestrian sideswipe impacts were computationally reconstructed; a fast-walking pedestrian was collided laterally with the side of a moving vehicle at 25 or 40 km/h, which resulted in rotating the pedestrian’s body axially. Potential severity of traumatic brain injury (TBI) was assessed using linear and rotational acceleration pulses applied to the head and by measuring intracranial brain tissue deformation. We found that TBI risk due to secondary head strike with the ground can be much greater than that due to primary head strike with the vehicle. Further, an ‘effective’ head mass, meff, was computed based upon the impulse and vertical velocity change involved in the secondary head strike, which mostly exceeded the mass of the adult head-form impactor (4.5 kg) commonly used for a current regulatory impact test for pedestrian safety assessment. Our results demonstrated that an SUV is more aggressive than a sedan due to the differences in frontal shape. Additionally, it was highlighted that a striking vehicle velocity should be lower than 25 km/h at the moment of impact to exclude the potential risk of sustaining TBI, which would be mitigated by actively controlling meff, because meff is closely associated with a rotational acceleration pulse applied to the head involved in the final event of ground contact

Smoothing Control of Wind Farm Output Fluctuations by Fuzzy Logic Controlled SMES

Due to random variations of wind speed, the output power and terminal voltage of a fixed speed wind generator fluctuate continuously. These irregularities in power output are affecting both the power quality and reliability. It is reported that STATCOM/SMES (Superconducting Magnetic Energy Storage) system can significantly decrease voltage and output power fluctuations of grid connected fixed speed wind generator. But the main problem in wind generator output power smoothing is the choice of the reference output power, because it corresponds to energy storage capacity. The storage capacity of SMES that is sufficient for the smoothing control but as small as possible is very important, considering cost effectiveness. In this paper, a fuzzy logic controlled STATCOM/SMES system is proposed, in which both SMA (Simple Moving Average) and EMA (Exponential Moving Average) are used to generate output power reference. Real wind speed data are used in the simulation analyses, whichvalidate the effectiveness of the proposed control strategy. Simulation results clearly show that the proposed STATCOM/SMES system can smooth well the wind generator output power and also maintain the terminal voltage at rated level in both cases when SMA or EMA is used to generate output reference power. Finally, it is shown that reference output power generated by EMA provides better performance with reduced SMES storage capacity than that of output power generated by SMA.Keywords: Minimization of fluctuations, fixed speed wind generator, STATCOM/SMES, simple moving average (SMA) and exponential moving average (EMA), and wind farm (WF).DOI:http://dx.doi.org/10.11591/ijece.v1i2.18

Spontaneous Subcutaneous Sarcoma in a 50-week-old Male Wistar Hannover GALAS Rat

A subcutaneous mass was noted in the abdomen of a 50-week-old male Wistar Hannover GALAS rat. Histologically, the tumor was composed of vimentin-positive small round cells with scant cytoplasm arranged in a trabecular, sheet or pericytoma-like pattern and spindle cells arranged in a bundle pattern and vimentin-negative round cells proliferating in an island-shaped pattern. Argentophilic thin fibers were observed to wrap up the individual cells, and some of the tumor cells showed coexpression of vimentin and cytokeratin that formed juxtanuclear globes in the cytoplasm by double immunohistostaining. Transmission electron microscopy did not reveal any characteristic features suggesting cellular differention toward a specific cell type. Based on these findings, it was difficult to specify the origin, and the tumor was diagnosed as a poorly differentiated mesenchymal tumor and classified as a sarcoma, NOS (not otherwise specified)

The effect of reduced glutathione on the toxicity of silver diamine fluoride in rat pulpal cells

Introduction: Due to its ability to arrest untreated dental caries, silver diamine fluoride (SDF) has been advocated for indirect pulp capping procedures. However, the high concentrations of silver and fluoride in SDF raise concerns about its biocompatibility to pulpal tissues. Objectives: This study aimed to investigate the effect of SDF on the viability, alkaline phosphatase (ALP) activity, and morphology of pulpal-like cells (RPC-C2A) and to evaluate the influence of reduced glutathione (GSH) on SDF-induced cytotoxicity and deposit formation on dentin. Methodology: The cytotoxicity of diluted 38% SDF solutions (10-4 and 10-5), with or without the addition of 5 mM or 50 mM GSH, was evaluated at 6 and 24 hours. Cell viability was detected using WST-8 and the effect on ALP activity was performed using an ALP assay kit. Cell morphology was observed using a phase-contrast microscope. Scanning electron microscopy analysis was conducted to evaluate the effect of GSH incorporation or conditioning on SDF-induced deposit formation on dentin discs. Cytotoxicity data were analyzed by two-way analysis of variance (ANOVA) and Tukey post hoc tests (p<0.05). Results: There were significant differences between the groups. The results demonstrated that all tested SDF dilutions caused a remarkable cytotoxic effect, while the addition of GSH prevented SDF-induced damage at 6-hour exposure time in the higher dilution of SDF. Dentin treated with plain SDF or GSH-incorporated SDF solution showed deposit formation with occluded dentinal tubules, unlike the other groups. Conclusion: SDF severely disturbed the viability, mineralization-ability, and morphology of pulpal-like cells, while controlled concentrations of GSH had a short-term protective effect against SDF-induced damage. GSH showed an inhibitory effect on SDF-induced dentinal deposit formation. Further research is warranted to evaluate the effect of GSH on caries-arresting, anti-hypersensitivity, and antibacterial functions of SDF

A design fuzzy logic controller for a permanent magnet wind generator to enhance the dynamic stability of wind farms

In this paper, a design fuzzy logic controller for a variable speed permanent magnet wind generator connected to a grid system through a LC-filter is proposed. A new current control method of grid side conversion is developed by integrating the fuzzy controller, in which both active and reactive power, delivered to a power grid system, is controlled effectively. The fuzzy logic controller is designed to adjust the gain parameters of the PI controllers under any operating conditions, so that the dynamic stability is enhanced. A new simple method, based on frequency response of the bode diagram, is proposed in the design of the fuzzy logic controller. To evaluate the controller system capabilities, simulation analyses are performed on a small wind farm model system including an induction wind generator connected to an infinite bus. The simulations have been performed using PSCAD/EMTDC. Simulation results show that the proposed control scheme is more effective for enhancing the stability of wind farms during temporary and permanent network disturbances and randomly fluctuating wind speed, compared with that of a conventional PI controller

Feasibility Study of a Wearable Haptic knob System

In this study, we develop an event-based wearable haptic knob system that can be used in three-dimensional space. The first step involves building custom-built brakes and attaching them to a human forearm to achieve a wearable haptic knob. The display is built using a carbon-fiber frame. As our system is experiment-based, target torque curves are collected by a force sensor before using the torque representation. We confirm the effectiveness of our developed display through three operations, namely doorknob rotation, valve closing, and valve opening by the test subject. In the first step, the rotational axis was fixed on a table. These results are then used to develop the perfect wearable haptic system that includes a rotational axis in the display

Spontaneous Pneumomediastinum: Report of a Case and Review of Literature

Spontaneous pneumomediastinum, defined as the presence of free air in the mediastinal structures, is a rare disease that usually take a good course with conservative therapy. However, clinicians are usually unfamiliar with the disease because of its infrequency. We report herein a case of spontaneous pneumomediastinum following an episode of violent cough. The patient was treated conservatively after hospitalization and got well without any medical problems. In addition we reviewed characteristics of spontaneous pneumomediastinum reported so far in the Japanese literature. The result of our review suggests that the typical patient with spontaneous pneumomediastinum is a young man with a slender build. In most patients, spontaneous pneumomediastinum occurs in conjunction with condition causing high airway pressure. None of the patients described in the literature developed serious complications such as cardiac insufficiency or airway compromise, and none of the cases without concomitant pneumothorax required any medical care. In conclusion, familiarity with this rare disease is crucial to provide appropriate treatment

Effects of teaching motor skills to others on the persistence of motor learning

The purpose of this study was to examine the effects of teaching motor skills to others on the survivability of motor learning effects. 20 healthy adults were randomly assigned to two conditions a teaching conditions and reading a magazine condition (control conditions). The number of times of turning was measured before and after each condition. In both conditions, the number of ball rotations and the number of improvements increased 30 minutes after the task was completed compared to before the task. Additionally, the number of improvements in ball rotation was significantly higher in the teaching condition than in the control condition. In the teaching condition, the number of ball turnings significantly increased 30 minutes after the end of the condition compared to before the condition. These results suggested that task for teaching motor skill to others might be useful for improving motor learning