Global tomographic images of mantle plumes and subducting slabs: Insight into deep Earth dynamics

In what case do you like reading so much? What about the type of the complex population dynamics a theoretical empirical synthesis book? The needs to read? Well, everybody has their own reason why should read some books. Mostly, it will relate to their necessity to get knowledge from the book and want to read just to get entertainment. Novels, story book, and other entertaining books become so popular this day. Besides, the scientific books will also be the best reason to choose, especially for the students, teachers, doctors, businessman, and other professions who are fond of reading.

Complex Population Dynamics: A Theoretical/Empirical Synthesis

We have determined a detailed three-dimensional P wave velocity structure of the Japan subduction zone to 500-km depth by inverting local, regional, and teleseismic data simultaneously. We used 45,318 P wave arrivals from 1241 shallow and deep earthquakes which occurred in and around the Japan Islands. The arrival times are recorded by the Japan University Seismic Network which covers the entire Japan Islands densely and uniformly. We also used 4211 travel time residuals from 100 teleseismic events which are read from seismograms recorded by seismic stations in northeastern Japan. In comparison with the previous results obtained from only local and regional events, the present result for the area around the lower plate boundary and the mantle below the plate is determined more reliably because of the addition of 7035 data from 100 teleseismic events and 41 very deep earthquakes. In the crust and uppermost mantle, low-velocity zones are clearly visible beneath active volcanoes. In the mantle wedge the low-velocity zones generally parallel with the slab and exist continuously to a depth of about 200-km, which is consistent with the petrological, geochemical and geodynamic studies. We consider that the existence of volcanism-related low-velocity anomalies in the mantle wedge is a general Seismological characteristic of subduction zones, in light of all the available tomographic results for many subduction zones in the world. The Pacific slab beneath Japan is imaged more clearly than in previous studies as a high-velocity zone with a thickness of 80–90 km and a P wave velocity 4–6% higher than the normal mantle. Lower velocity anomalies are found in the mantle below the slab.

/pdf/deep-structure-of-japan-subduction-zone-as-derived-from-yymvxfstz1.pdf

Deep structure of Japan subduction zone as derived from local, regional, and teleseismic events

Unmanned aerial vehicles (UAVs) can be used to serve as aerial base stations to enhance both the coverage and performance of communication networks in various scenarios, such as emergency communications and network access for remote areas. Mobile UAVs can establish communication links for ground users to deliver packets. However, UAVs have limited communication ranges and energy resources. Particularly, for a large region, they cannot cover the entire area all the time or keep flying for a long time. It is thus challenging to control a group of UAVs to achieve certain communication coverage in a long run, while preserving their connectivity and minimizing their energy consumption. Toward this end, we propose to leverage emerging deep reinforcement learning (DRL) for UAV control and present a novel and highly energy-efficient DRL-based method, which we call DRL-based energy-efficient control for coverage and connectivity (DRL-EC3). The proposed method 1) maximizes a novel energy efficiency function with joint consideration for communications coverage, fairness, energy consumption and connectivity; 2) learns the environment and its dynamics; and 3) makes decisions under the guidance of two powerful deep neural networks. We conduct extensive simulations for performance evaluation. Simulation results have shown that DRL-EC3 significantly and consistently outperform two commonly used baseline methods in terms of coverage, fairness, and energy consumption.

Energy-Efficient UAV Control for Effective and Fair Communication Coverage: A Deep Reinforcement Learning Approach

As the scale of devices becomes small, thermal control and heat dissipation from these devices can be effectively accomplished through the implementation of microchannel passages. The small passages provide a high surface area to volume ratio that enables higher heat transfer rates. High performance microchannel heat exchangers are also attractive in applications where space and/or weight constraints dictate the size of a heat exchanger or where performance enhancement is desired. This survey article provides a historical perspective of the progress made in understanding the underlying mechanisms in single-phase liquid flow and two-phase flow boiling processes and their use in high heat flux removal applications. Future research directions for (i) further enhancing the single-phase heat transfer performance and (ii) enabling practical implementation of flow boiling in microchannel heat exchangers are outlined.

History, Advances, and Challenges in Liquid Flow and Flow Boiling Heat Transfer in Microchannels: A Critical Review

The experimental research on microtube heat transfer and fluid flow of distilled water

This article presents a method for picking broadband seismic phases by using backpropagation neural networks (BPNNs) as detectors. By combining the results from three BPNN detectors—long term, mid-term, and short term—the method combines the features of short term9s higher accuracy and long term9s lower false alarm rate. We demonstrate that proper pre- and postprocessing of the data can help to improve the system9s performance. The determination of the architecture and parameters for BPNNs is also discussed in this article. The devised BPNN detector is applied to 1254 broadband seismograms of the IRIS network to determine the first arrival, which is expected to be used in tomographic studies of the mantle structure. The results show that the first arrival can be identified for more than 95% of the 1254 seismograms. The automatically picked travel times have a reasonable accuracy; more than 85% have an error of less than 1 sec, and about 80% have an error of less than 0.5 sec.

An artificial neural network approach for broadband seismic phase picking

A method for the design of 3D scaffolds for high-density cell attachment and determination of optimum perfusion culture conditions.

Active enhancement of evaporation of a liquid drop on a hot solid surface using a static electric field

After severe natural disasters, being able to communicate is key to effective disaster relief. When survivors are injured and trapped in remote places, for instance, they need to inform rescue workers about their situation in order to get help. The necessary infrastructure can be badly damaged, making the delivery of that information impossible. Even the disaster countermeasures of mobile operators might still leave coverage holes where there is no connection to any cellular network. In this work, we propose the use of Unpiloted Aerial Vehicles (UAVs) as data mules to provide means of communication to survivors in those coverage holes. Having a fleet of UAVs, the generation of suitable flight paths is the first step required, followed by their assignment to the UAVs. This problem has been modeled as an integer linear program. Due to the computational complexity, a heuristic solving algorithm is proposed to solve the formulated problem. The optimal and the heuristic solution both have been implemented and evaluated against each other.

Kiyoshi Takano

Papers

The experimental research on microtube heat transfer and fluid flow of distilled water

An artificial neural network approach for broadband seismic phase picking

A method for the design of 3D scaffolds for high-density cell attachment and determination of optimum perfusion culture conditions.

Active enhancement of evaporation of a liquid drop on a hot solid surface using a static electric field

Mission planning for UAV-based opportunistic disaster recovery networks