Dependable multi‐population improved brain storm optimization with differential evolution for optimal operational planning of energy plants

This paper proposes dependable multi‐population improved brain storm optimization with differential evolution for optimal operational planning of energy plants. The problem can be formulated as a mixed‐integer nonlinear programming problem and various evolutionary computation techniques such as particle swarm optimization (PSO), differential evolutionary PSO (DEEPSO), multi‐population DEEPSO (MP‐DEEPSO), and brain storm optimization have been applied so far. When optimal operational planning of numbers of energy plants is calculated simultaneously in a data center, a challenge is to generate optimal operational planning as rapidly as possible considering control intervals and numbers of treated plants. One of the solutions for the challenge is speeding up by parallel and distributed computing. It utilizes numbers of processes and countermeasures for various faults of the distributed processes should be considered. Moreover, successive calculation at every control interval is required for keeping customer services. Therefore, sustainable (dependable) calculation keeping appropriate solution quality is required even if some of the calculation results cannot be returned from distributed processes. It is verified that total energy cost by the proposed dependable multi‐population improved brain storm optimization with differential evolution strategy based method is lower than those by the compared methods, and higher quality of solutions can be kept even with high fault probabilities.     

7Li 2D CSI of human brain on a clinical scanner

Lithium salts have been widely used in the treatment of mood disorders, but the mechanism of action is still not clear. In this work, a methodology for two-dimensional Lithium-7 imaging on clinical systems is presented. The data were acquired using a phosphorus volume head coil that was re-tuned for the Lithium-7 frequency. A spectroscopic sequence was used to acquire the free induction decay (FID) after volume excitation using a hard pulse. The results obtained on the head of patients undergoing lithium treatment (n = 7, 0.6 mEq/1 average serum level) demonstrate that images of adequate signal to noise ratio (100:1) can be obtained in acceptable imaging times (55 min) using the proposed methodology. The distribution of ’’Li appears uniform in the brains of the patients studied.     

Determination of the Mosaic Angle Distribution of Grafoil Platelets Using Continuous-Wave NMR Spectra

We described details of a method to estimate with good accuracy the mosaic angle distributions of microcrystallites (platelets) in exfoliated graphite like Grafoil which is commonly used as an adsorption substrate for helium thin films. The method is based on analysis of resonance field shifts in continuous-wave (CW) NMR spectra of ³He ferromagnetic monolayers making use of the large nuclear polarization of the adsorbate itself. The mosaic angle distribution of a Grafoil substrate analyzed in this way can be well fitted to a gaussian form with a 27.5±2.5 deg spread. This distribution is quite different from the previous estimation based on neutron scattering data which showed an unrealistically large isotropic powder-like component.     

Hydrogen enhanced crack propagation of SCM440H low-alloy steel under long-term varying load

Crack propagation behavior of SCM440H low-alloy steel enhanced by absorbed hydrogen is investigated. Six materials tempered at different temperatures are used. Effects of stress ratio, loading frequency, hold time and material hardness on the crack propagation rate are examined under long-term varying load. Tests have been performed under continuous hydrogen charging, in which the crack tip has been isolated from the electrolyte and kept dry. An acceleration of crack propagation rate about six times compared to the uncharged material is found in all materials. In addition to this, however, an unexpected acceleration of crack propagation up to 1000 times is experienced under certain conditions. In materials with Vickers hardness higher than 280 tested at low frequency, the above marked acceleration is experienced. The crack surface morphology is quasi-cleavage. This critical hardness (HV = 280) is a little lower than the usually accepted critical hardness for delayed failure (HV = 350). In material with Vickers hardness lower than 268, however, such a marked acceleration is not experienced.     

Constitutive parameters for earthquake rupture dynamics based on high-velocity friction tests with variable sliprate

To reproduce the dynamic rupture process of earthquakes, the fault geometry, initial stress distribution and a frictional constitutive law on the fault are important parameters as initial and boundary conditions of the system. Here, we focus on the frictional constitutive relation on the fault. During a high-speed rupture, fault strength decreases as slip develops which can be described by a slip weakening equation. To understand the physical process of stress breakdown during the dynamic rupture of earthquakes, we investigated the friction behavior of rocks in the laboratory by direct measurements of traction evolution with slip in response to a given slip history. We employed a high-speed rotary shear apparatus introduced at National Research Institute for Earth Science and Disaster Prevention (NIED). This apparatus has a capability of sliding with predefined variable velocities using a servo-controlled system. We used a pair of granite cylindrical specimens with a diameter of 25 mm. As an input signal, we used a regularized Yoffe function to investigate the scale dependence of fracture energy and slip weakening distance (D _c). We observed a positive correlation between D _c and total slip, keeping the maximum slip velocity constant. These conditions correspond to those for earthquakes with the same stress drop and varying magnitudes. Finally, we used a real fault motion; a fault parallel velocity seismogram observed at PS10, 3 km away from the surface fault trace and above the high slip region during the 2002 Denali, Alaska, earthquake. We compared the seismological fracture energy with the corresponding D _c. The relation is linear with an inflection point at D _c = 0.2 m, where the gradient changes. Another interesting feature is that the maximum value of D _c is about 4m even if the total slip exceeds 12 m.     

Underwater Blasting Work by an Electromagnetic Firing Method

There are many difficulties and dangers when carrying out underwater blasting in a rapid stream. The electromagnetic firing method is a special type of the remote control firing method and has a distinct advantage to the underwater blasting. The principle of this method is based on electromagnetic phenomena, the induced electromotive force by the coil which is set into the electromagnetic field is applied to fire the detonation cap. In this paper, the authors discuss the fundamental theory of the electromagnetic field caused by the exciting loop, and the effect of the conductive medium. As an example, they present the procedure and results of an actual underwater blasting work which is the first application of this technique.