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The reliability of power systems with high penetration of renewables, a fast response mechanism, and precise decision-making scheme is more important than ever. This study presented a novel scheme that utilizes the predicted frequency nadir after a generation trip event to initiate necessary ancillary services such as fast spinning reserve units, energy storage units, and demand responses to restore the frequency back to the secure operating range. The proposed scheme coordinates Under-Frequency Load Shedding (UFLS) with ancillary services in the sense that the unnecessary load shedding can be avoided. By using the proposed scheme, the system becomes more resilient against disturbances, and the actions of load shedding are minimized. In this scheme, the frequency data is captured by phasor measurement units (PMUs), and a frequency nadir prediction algorithm is proposed. We demonstrate the effectiveness of the proposed scheme by using 1700-bus power system simulations and realistic frequency data from real generation trip events captured by a laboratory micro-phasor measurement unit (μPMU). [ABSTRACT FROM AUTHOR]

This paper presents an innovative fault location method for multi-terminal nonhomogeneous transmission lines by using synchronized voltage and current phasors acquired from phasor measurement units or intelligent electronic devices. We extend the previously published two-terminal and three-terminal nonhomogeneous transmission line fault location techniques developed in our lab to multi-terminal nonhomogeneous transmission lines. Specifically, a graph theory based indices and an optimal calculation data window is applied to identify the faulty line branch and to mitigate the undesirable influence caused by dc decay and the arc phenomenon of circuit breaker. The high performance of the proposed fault location method is validated by simulation results and real world utility fault data. [ABSTRACT FROM AUTHOR]

For overhead transmission line monitoring, wireless sensor networks offer a low-cost solution to connect sensors on towers with the control center. However, these networks cannot meet stringent quality of service (QoS) requirements, in terms of packet delivery ratio and delay. Also, it is necessary to ensure robustness such that data can be delivered when a tower fails. In view of the QoS and robustness requirements, wide area network (WAN) connections, such as cellular and satellite network are needed, on top of wireless sensor networks. Different WAN connections have different characteristics in terms of availability, performance, and cost. We have proposed a novel scheme, called optimal placement for QoS and robustness (OPQR), which uses the canonical genetic algorithm to determine the numbers, locations, and types of WAN connections to be deployed to minimize cost while satisfying the QoS and robustness requirements. Evaluation results confirm that OPQR can indeed fulfil the desired requirements at minimum cost, and it is a very useful tool in cost-efficient communication network planning for transmission line monitoring. Specifically, OPQR can maintain cost below USD50 per day for a transmission line that has 80 towers spanning across 32 km, while maintaining the packet delay below 100 ms, packet delivery ratio above 99.99%, and each flow has two node-disjoint paths to the control center. [ABSTRACT FROM AUTHOR]

This paper presents a new method based on phasor measurement units (PMUs) for the estimation of voltage stability margin in a power system to increase operator's situational awareness. The method assumes a PMU measurement preprocessing technique as a priori in order to eliminate data inconsistency and uncertainty caused by random load disturbances. The measurements are then used in the computation of voltage stability margin based on the coupled single-port Thevenin equivalent model and the cubic spline extrapolation technique. Moreover, some practical operating constraints such as the generator reactive power limits are taken into account for practical assessment of the method's performance. Extensive case studies conducted on several standard IEEE test systems are used to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

In this paper, a novel phase-shedding control scheme for multiphase interleaved dc–dc converters is proposed to improve the light load efficiency. The proposed phase-shedding scheme is based upon power efficiency estimation with a numerically constructed lookup table and a phase configuration selector to automatically determine the load current point of phase shedding for the minimization of the power loss during the light load condition. The proposed scheme is verified on a three-phase-interleaved dc–dc synchronous buck converter with a 12 V input and 1.2 V, 60 A output. Experimental results are presented to demonstrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Black start is the primary procedure deployed for rapid recovery from a complete blackout. For isolated power systems such as the Taiwan power system (TPS), a reliable and efficient black start procedure is more important than interconnected power systems. In this paper, a black start decision-supporting system (BSS) with an interactive graphical user interface (GUI) has been developed. BSS can rapidly generate optimal black start strategies according to the updated system data configuration and objective function; furthermore, BSS can automatically simulate the strategies and visualize the results. By applying the BSS to evaluate the black start strategies for TPS, the effectiveness of BSS has been demonstrated. The BSS has been utilized by Taiwan Power Company (TPC) for black start planning with comparison to traditional manual planning. With the aid of BSS, the dispatchers are equipped with more support and the restoration risk can be much alleviated. [ABSTRACT FROM PUBLISHER]

Abstract: In this paper we consider the effect of friction force on the contact behavior of an elastica constrained inside a straight channel with clearance. The elastica is fed in the channel through a space-fixed input clamp and protrude out of an elastically suspended output clamp. The two pads of the output clamp are assumed to be pre-compressed. Coulomb friction is assumed to be present on the lateral walls of the channel and in the output clamp. Focus is placed on the relative motion between the input and output ends of the beam. The beam may buckle when the input end is pushed in the channel and the output end is stuck due to friction resistance. Four types of contact patterns between the elastica and the constraining channel walls may occur when the beam buckles; they are rolling point contact, combined rolling and sliding point contact, rolling line contact, and sliding line contact. When the friction resistance at the output end is overcome, the beam will protrude out of the channel. When friction is present between the elastica and the lateral walls, hysteresis occurs when the input end undergoes a load–unload cycle. A small-deformation theory is also developed for the case when the spacing between the constraining walls is small. As expected, the accuracy of the small-deformation theory deteriorates as the spacing of the constraining walls increases. [Copyright &y& Elsevier]

Risks from ground fault transfer (GFT) on closed-loop high-voltage (HV) underground distribution systems (UGDS) with cables running in a common route are assessed based on simulations by the Alternative Transienta Program (ATP) of the Electromagnetic Transients Program. To model the system, the configuration of a real and typical closed-loop HV UGDS is explicitly depicted. The complex connecting relationships between cable metallic shields, grounding electrodes, parallel ground continuity conductors (PGCCs), and surge suppressors at manholes and substations are clearly shown. Then, through the system modeling and simulation by ATP, the GFT characteristics (i.e., the distributions of currents and potentials on cable metallic shields and PGCCs along the cable length are analyzed). Based on the simulation results, the risks from GFT on personnel, equipment, devices, or other associated systems are assessed. Finally, the damages caused by a three-phase ground fault in a customer substation are surveyed to certify assessment result of risks and the severity of GFT on closed-loop HV UGDS with cables running in a common route. [ABSTRACT FROM PUBLISHER]

Abstract: In this paper we consider the effect of friction force on the contact behavior of an elastica inside a circular channel with clearance. The elastica is partially clamped at both the input and output ends of the channel. Coulomb friction is assumed to be present at the output end and on the constraining walls. Focused is placed on the relative motion between the input end and the output end of the elastica. Shooting method is adopted to solve for the quasi-static behavior of the elastica movement. Four types of contact patterns between the elastica and the constraining channel walls may occur when the input end moves in and out of the channel; they are rolling point contact, combined rolling and sliding point contact, rolling line contact, and sliding line contact. When the input end undergoes a sinusoidal motion, the output end either ceases to move at all, or follows exactly the input end motion. These two phases of output end motion occur subsequently, one immediately after the other. In general, the output end lags behind the input end. Experimental observations on the lagging phenomenon at the output end confirm the theoretical prediction. [Copyright &y& Elsevier]

This paper presents a novel solution of a hand-held external controller to a miniaturized capsule endoscope in the gastrointestinal (GI) tract. Traditional capsule endoscopes move passively by peristaltic wave generated in the GI tract and the gravity, which makes it impossible for endoscopists to manipulate the capsule endoscope to the diagnostic disease areas. In this study, the main objective is to present an endoscopic capsule and a magnetic field navigator (MFN) that allows endoscopists to remotely control the locomotion and viewing angle of an endoscopic capsule. The attractive merits of this study are that the maneuvering of the endoscopic capsule can be achieved by the external MFN with effectiveness, low cost, and operation safety, both from a theoretical and an experimental point of view. In order to study the magnetic interactions between the endoscopic capsule and the external MFN, a magnetic-analysis model is established for computer-based finite-element simulations. In addition, experiments are conducted to show the control effectiveness of the MFN to the endoscopic capsule. Finally, several prototype endoscopic capsules and a prototype MFN are fabricated, and their actual capabilities are experimentally assessed via in vitro and ex vivo tests using a stomach model and a resected porcine stomach, respectively. Both in vitro and ex vivo test results demonstrate great potential and practicability of achieving high-precision rotation and controllable movement of the capsule using the developed MFN. [ABSTRACT FROM PUBLISHER]

Abstract: Rhodococcus erythropolis strain NTU-1 was isolated from oil-contaminated aqueous sludge and can grow at relatively high concentration of n-hexadecane as the only carbon source. The higher concentration of n-hexadecane, the faster degradation rate by NTU-1. Approximately 20,000ppmv (2%) of n-hexadecane were degraded in a treatment with 100,000ppmv (10%) within 4days of incubation. The amount of H+ ions released corresponded well to the carbon-chain length of the n-alkanes (either n-tetradecane, n-hexadecane or n-octadecane). The correspondence was 0.634mmol H+ ions accumulated per mole of n-hexadecane biodegraded. Using this correspondence, n-alkanes consumption can be closely estimated by monitoring pH changes in the medium. This procedure presents an alternative to other complex procedures that use organic solvent extractions and gas chromatography analysis. The procedure following the H+ ions accumulation was validated in a fed-batch bioreactor operation. [Copyright &y& Elsevier]

Abstract: Rhodococcus erythropolis strain NTU-1 degraded C10–C32 n-alkanes in diesel oil or crude oil. While degrading these n-alkanes, NTU-1 also trapped most other oil constitutes that were not degraded in biofloccules. In batch cultures with 10,000ppmv diesel or crude oil, approximately 90% oil removal was achieved within 4 days (about 30% of biodegradation and 60% of biosorption). In bioreactors with aeration and pH adjustment, an intermittent feed of 42,000ppmv n-hexadecane resulted in approximately 87% removal within 4 weeks (24% of biodegradation and 63% of biosorption), and an intermittent feed of 35,000ppmv diesel or crude oil resulted in more than 90% removal within 2 weeks (about 20% of biodegradation and 74% of biosorption). The results demonstrate the feasibility for the application of R. erythropolis strain NTU-1 to the bioremediation of sites polluted with petroleum spills. [ABSTRACT FROM AUTHOR]

Abstract: An alkane-biodegrading bacterium identified as Rhodococcus erythropolis (NTU-1 strain) was isolated from petroleum contaminated soil. The major purpose of the current research was to study the issues regarding biofloccules formation and cell surface hydrophobicity of NTU-1. When long-chain alkanes are supplied as the carbon source, NTU-1 tends to form biofloccules and remove significant amount of alkanes by biodegradation and physical trapping. Approximately, more than 95% of each alkane could be efficiently removed within 40–68h. The bioremediation process was accompanied by formation of biofloccules with size ranging from 0.1 to 2cm in diameter. The MATH test and the hydrophobic slide experiment suggested that NTU-1 might possess a hydrophobic cell surface which is one of the important factors in the formation of biofloccules. It provides the interaction of cells with hydrocarbon droplets effectively and further aggregate into larger clumps. Besides, when grown on n-hexadecane, experimental results revealed that there were at least 11 different growth-associated fatty acids produced, with carbon chain length ranging from 12 to 24, and cell surface hydrophobicity was enhanced via accumulation at the cell surface. [Copyright &y& Elsevier]

Abstract: This paper proposes a special protection scheme to prevent power system blackout due to a sequence of relay trip events based on phasor measurement units (PMUs). In a control center, we use PMU''s to monitor the generators and the major EHV transmission lines of a power system, and apply an instability prediction algorithm for initiating a special protection schemes (SPS) to avoid a sequence of relay trip events whenever necessary. When a fault happens, we group the generators swinging coherently and reduce the system to One-Machine-Infinite-Bus (OMIB) system. The remedial control actions consist of load shedding and generation tripping. The strategy for determining the amount of remedial control actions is a proposed relay setting limited equal-area criterion for OMIB. A case study of Taiwan power system assumed to be equipped with proposed special protection scheme is conducted. Encouraging results are obtained. [Copyright &y& Elsevier]

The theory and algorithms of the proposed technique have been presented in Part I of this two-paper set. In Part II of this two-paper set, the proposed technique is evaluated by considerable simulation cases simulated by the Mattab/Power system Blockset simulator. For the proposed fault detector, the trip time achieved can be up to 3.25 ms and the average value of trip times is about 8 ms for both permanent and arcing faults on transmission lines. For the proposed fault locator, the accuracy can be up to 99.99% and the error does not exceed 0.45%. Moreover, the proposed arcing fault discriminator can discriminate between arcing and permanent faults within four cycles after fault inception. It has proven to be an effective tool to block reclosing on the permanent faults in the computer simulations. The simulation results also demonstrate that the presented extended discrete Fourier transform algorithm eliminates effectively the error caused by exponentially decaying dc offset on fundamental and harmonic phasor computations. Finally, a test case using the real-life measured data proves the feasibility of the proposed technique. [ABSTRACT FROM AUTHOR]

A new fault detection/location technique with consideration of arcing fault discrimination based on phasor measurement units for extremely high voltage/ultra-high voltage transmission lines is presented in this two-paper set Part I of this two-paper set is mainly aimed at theory and algorithm derivation. The proposed fault detection technique for both arcing and permanent faults is achieved by a combination of a fault detection index |M| and a fault location index |D|, which are obtained by processing synchronized fundamental phasors. One is to detect the occurrence of a fault and the other is to distinguish between in-zone and out-of- zone faults. Furthermore, for discriminating between arcing and permanent faults, the proposed technique estimates the amplitude of arc voltage by least error squares method through the measured synchronized harmonic phasors caused by the nonlinear arc behavior. Then, the discrimination will he achieved by comparing the estimated amplitude of arc voltage to a given threshold value. In addition, in order to eliminate the error caused by exponentially decaying dc offset on the computations of fundamental and harmonic phasors, an extended discrete Fourier transform algorithm is also presented. [ABSTRACT FROM AUTHOR]

Presents a study which proposed the optimal planning of passive-harmonic-filters set at high voltage level. Basis for the increase in the harmonic components of current and voltage waves in the power system; Conclusions.

Provides information on a study which developed a novel class of fuzzy hyperrectangular composite neural networks which utilize synchronized phasor measurements. Hybrid training algorithm; Simulation results; Conclusion of the study.

Presents an innovative fast global optimization technique, hybrid partial gradient descent/simulated annealing (HPGDSA) for optimal VAR planning. Problem formulation; Fast global optimization technique; The HPGDSA algorithm; Conclusions of the study.

Presents a new search algorithm for the closest unstable equilibrium point (UEP) in transient stability region estimate. Review of the closest UEP method; Theoretical justification for numerical algorithm; Application of algorithm to three-machine system; Simulation results obtained.

The analysis of severe blackouts has become an essential part of transmission grid planning and operation. This may include evaluation of rare-event probabilities, which can be difficult to estimate. While simulation offers flexibility to model large complex systems, efficiency remains a big concern when estimating very small probabilities. This paper presents an effective simulation technique to evaluate rare-event probabilities associated with cascading blackouts in an electric grid. We test our technique on an IEEE 118-bus electric network and show that it can dramatically improve simulation efficiency. We also demonstrate that the proposed technique can effectively locate vulnerable links. These are links whose failures lead to the highest probabilities of a blackout event. [ABSTRACT FROM PUBLISHER]

Summary The Gram-positive bacterium Nocardioides sp. strain CF8 uses a membrane-associated monooxygenase (pBMO) to grow on butane. The nucleotide sequences of the genes encoding this novel monooxygenase were revealed through analysis of a de novo assembled draft genome sequence determined by high-throughput sequencing of the whole genome. The pBMO genes were in a similar arrangement to the genes for ammonia monooxygenase (AMO) from the ammonia-oxidizing bacteria and for particulate methane monooxygenase (pMMO) from the methane-oxidizing bacteria. The pBMO genes likely constitute an operon in the order bmoC, bmoA and bmoB. The nucleotide sequence was less than 50% similar to the genes for AMO and pMMO. The operon for pBMO was confirmed to be a single copy in the genome by Southern and computational analyses. In an incubation on butane the increase of transcriptional activity of the pBmoA gene was congruent with the increase of pBMO activity and suggested correspondence between gene expression and the utilization of butane. Phylogenetic comparison revealed distant but significant similarity of all three pBMO subunits to homologous members of the AMO/pMMO family and indicated that the pBMO represents a deeply branching third lineage of this group of particulate monooxygenases. No other bmoCAB-like genes were found to cluster with pBMO lineage in phylogenetic analysis by database searches including genomic and metagenomic sequence databases. pBMO is the first example of the AMO/pMMO-like monooxygenase from Gram-positive bacteria showing similarities to proteobacterial pMMO and AMO sequences. [ABSTRACT FROM AUTHOR]

Abstract: The tuning of the PSS parameters for a multi-machine power system is usually formulated as an objective function with constraints consisting of the damping factor and damping ratio. A novel mixed-integer ant direction hybrid differential evolution algorithm, called MIADHDE, is proposed to solve this kind of problem. The MIADHDE is improved from ADHDE by the addition of accelerated phase and real variables. The performances of three different objective functions are compared to the MIADHDE in this paper. Both local and remote feedback signals of machine speed deviation measurements can be selected as input signals to the PSS controllers in the proposed objective function. The New England 10-unit 39-bus standard power system, under various system configurations and loading conditions, is employed to illustrate the performance of the proposed method with the three different objective functions. Eigenvalue analysis and nonlinear time domain simulation results demonstrate the effectiveness of the proposed algorithm and the objective function with a remote signal. [Copyright &y& Elsevier]

Utilizing energy storage systems equipped with virtual/synthetic inertia control has emerged as one of the solutions to solve low inertia issues in power systems with massive penetration of renewables. However, while the aspect regarding the control of the synthetic inertia control has been widely investigated, the optimal placement of synthetic inertia control is rarely investigated. Therefore, the optimal placement of energy storage system with synthetic inertia control based on swarm‐based mean‐variance mapping optimization is proposed. The performance of the proposed method is tested by considering several cases, both single and multiple contingencies. By utilizing the proposed method, the optimal placement of energy storage system equipped with synthetic inertia control could be obtained, in which the resulting frequency response is better compared to randomly placed ones. The proposed method could also be applied by considering multiple contingencies in different locations. Furthermore, the resulting fitness values for different independent optimization repetitions for various study cases are consistent, leading to the efficacy to be applied in the actual power system planning. [ABSTRACT FROM AUTHOR]

This paper presents an autonomous navigation system for cost-effective magnetic-assisted colonoscopy, employing force-based sensors, an actuator, a proportional–integrator controller and a real-time heuristic searching method. The force sensing system uses load cells installed between the robotic arm and external permanent magnets to derive attractive force data as the basis for real-time surgical safety monitoring and tracking information to navigate the disposable magnetic colonoscope. The average tracking accuracy on magnetic field navigator (MFN) platform in x-axis and y-axis are 1.14 ± 0.59 mm and 1.61 ± 0.45 mm, respectively, presented in mean error ± standard deviation. The average detectable radius of the tracking system is 15 cm. Three simulations of path planning algorithms are presented and the learning real-time A* (LRTA*) algorithm with our proposed directional heuristic evaluation design has the best performance. It takes 75 steps to complete the traveling in unknown synthetic colon map. By integrating the force-based sensing technology and LRTA* path planning algorithm, the average time required to complete autonomous navigation of a highly realistic colonoscopy training model on the MFN platform is 15 min 38 s and the intubation rate is 83.33%. All autonomous navigation experiments are completed without intervention by the operator. [ABSTRACT FROM AUTHOR]

We developed a magnetic-assisted capsule colonoscope system with integration of computer vision-based object detection and an alignment control scheme. Two convolutional neural network models A and B for lumen identification were trained on an endoscopic dataset of 9080 images. In the lumen alignment experiment, models C and D used a simulated dataset of 8414 images. The models were evaluated using validation indexes for recall (R), precision (P), mean average precision (mAP), and F1 score. Predictive performance was evaluated with the area under the P-R curve. Adjustments of pitch and yaw angles and alignment control time were analyzed in the alignment experiment. Model D had the best predictive performance. Its R, P, mAP, and F1 score were 0.964, 0.961, 0.961, and 0.963, respectively, when the area of overlap/area of union was at 0.3. In the lumen alignment experiment, the mean degrees of adjustment for yaw and pitch in 160 trials were 21.70° and 13.78°, respectively. Mean alignment control time was 0.902 s. Finally, we compared the cecal intubation time between semi-automated and manual navigation in 20 trials. The average cecal intubation time of manual navigation and semi-automated navigation were 9 min 28.41 s and 7 min 23.61 s, respectively. The automatic lumen detection model, which was trained using a deep learning algorithm, demonstrated high performance in each validation index. [ABSTRACT FROM AUTHOR]

In this article, we propose a method for locating a magnetic capsule endoscope, which is utilized to observe the gastrointestinal tract, especially for colon. Recent studies mainly focus on either single-magnet positioning or multiple magnets positioning with similar scale in magnetic parameters, whereas these methods cannot be directly applied to the proposed magnetic-assisted capsule endoscope system, in which two magnets with big differences in magnetic parameters are used. An algorithm based on the Levenberg–Marquardt algorithm and a Hall sensor array is presented to solve this problem. Three different experiments have been carried out to validate the feasibility and effectiveness of the proposed method for the magnetic capsule positioning and orientation. [ABSTRACT FROM AUTHOR]

In a power system, the transmission network is the backbone of electricity delivery from power plants to load centers; hence, it becomes a critical issue for electrical engineers to shorten the service restoration time after a fault occurrence on the transmission line. This application paper integrates the two- and three-terminal hybrid transmission line fault location algorithms based on synchronized phasor measurements into the proposed cloud-computing-based fault location system to inspect the feasibility and practicality of our algorithms for the real transmission-line incidents. The computing results are performed via Google Map for authorized personal computers and the application for intelligent mobile devices is developed to assist engineers in acquiring the fault-event information immediately as well as in figuring out the fault position intuitively and quickly due to its visualization and navigation. Last but not the least, the suggested fault location system has already been applied to the practical 345- and 161-kV transmission networks of Taiwan Power Company for achieving the combination of theory and practice. Up to the present, the proposed system still yields excellent performance verified by realistic fault data. [ABSTRACT FROM AUTHOR]

Background and Study Aim: Current capsule endoscopy procedures are ineffective for upper gastrointestinal (GI) tract examination because they do not allow for operator-controlled navigation of the capsule. External controllability of a capsule endoscope with an applied magnetic field is a possible solution to this problem. We developed a novel magnetic-assisted capsule endoscope (MACE) system to visualize the entire upper GI tract. The present study evaluated the safety and feasibility of the MACE system for the examination of the upper GI tract, including the esophagus, stomach, and duodenum.Methods: The present open clinical study enrolled ten healthy volunteers. All participants swallowed a MACE, and an external magnetic field navigator was used for magnetic capsule manipulation in the upper GI tract. We assessed the maneuverability of the magnetic capsule and completeness of the MACE examination as well as the safety and tolerability of the procedure.Results: The present study enrolled ten healthy volunteers with a mean age and body mass index of 47.7 years and 25.6 kg/m2, respectively. One volunteer withdrew because of difficulty in swallowing the capsule. In total, nine volunteers underwent the MACE examination. The average examination time was 27.1 min. The maneuverability of the capsule was assessed as good and fair in 55.6 and 44.4% of the participants, respectively. The overall completeness of the examination in the esophagus, stomach, and duodenum was 100, 85.2, and 86.1%, respectively. No severe adverse events occurred during this study. All participants exhibited satisfactory tolerance of the MACE examination.Conclusion: The MACE system has satisfactory maneuverability and visualization completeness with excellent acceptance and tolerance. [ABSTRACT FROM AUTHOR]

This letter presents a fault location technique for three-terminal hybrid AC transmission lines with one off-service line branch by using synchrophasor data obtained from buses which are connected to in-service line branches. The proposed method adopts the two-terminal fault location technique to identify the faulted line branch and locate the fault point when a fault exists on the in-service line branch. Contrarily, if a fault exists on the off-service line branch, the apparent reactance that is obtained from synchronized voltage and current phasor sets of the junction point P, and sequence networks are both chosen to calculate the exact fault point. The performance evaluation shows that the proposed idea has high accuracy under different fault types and resistance. [ABSTRACT FROM AUTHOR]

Background: Colonoscopy is considered the most effective method for diagnosing colorectal diseases, but its application is sometimes limited due to invasiveness, patient intolerance, and the need for sedation. Objective: The aim of this study was to improve the problem of loop formation and shorten the cecal intubation time of colonoscopy by using a magnetic control system (MCS). Methods: Two experienced gastroenterologists, three trainees, and a novice repeated colonoscopy without or with MCS on three colonoscopy training model simulator cases. These cases were divided into introductory (case 2) and challenging levels (cases 4 and 5). The cecal intubation times were recorded. Results: For all cases, the average cecal intubation times for the experienced gastroenterologists with MCS were significantly shorter than without MCS (case 2: 52.45 vs. 27.65 s, p < 0.001; case 4: 166.7 vs. 120.55 s, p < 0.01; case 5: 130.35 vs. 100.2 s, p < 0.05). Those of the trainees also revealed significantly shorter times with MCS (case 2: 67.27 vs. 51 s, p < 0.01; case 4: 253.27 vs. 170.97 s, p < 0.001; case 5: 144.1 vs. 85.57 s, p < 0.001). Conclusion: Conducting colonoscopy with MCS is safe and smooth, and shortens the cecal intubation time by navigating the forepart of the colonoscope. In addition, all diagnostic and therapeutic benefits of conventional colonoscopy are retained. [ABSTRACT FROM AUTHOR]

A power-failure event occurred at the third nuclear power plant (TNPP) in Taiwan in 2001. A chain of events began at 09:36 p.m. on March 16 due to insulation failure associated with flashovers on the 345-kV transmission line. As a result, the 4.16-kV engineered safety features (ESF) buses at the TNPP experienced a loss of power for 2 h and 8 min. This accident was a class 3 emergency (e.g., a class 4 emergency will lead to an overall evacuation of local residents) based on the declared class of emergency in Taiwan. The purpose of this paper is to describe and analyze the chain of events leading to the loss of electrical power. Conclusions on the causes of the outage are drawn and modifications of the system structure are made to improve safety and reliability in a nuclear power plant. [ABSTRACT FROM PUBLISHER]

Postgrowth thermal annealing of an InGaN/GaN quantum-well sample with a medium level of nominal indium content (19%) was conducted. From the analyses of high-resolution transmission electron microscopy and energy filter transmission electron microscopy, it was found that thermal annealing at 900 °C led to a quasiregular quantum-dot-like structure. However, such a structure was destroyed when the annealing temperature was raised to 950 °C. Temperature-dependent photoluminescence (PL) measurements showed quite consistent results. Blueshift of the PL peak position and narrowing of the PL spectral width after thermal annealing were observed. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]