Approach and structure of stabilizing control system preventing an extension of synchronism loss

Recently, large-capacity power stations have been built far from load centers with long-distance transmission lines. Therefore, if a fault occurs at the line, generators in the large-capacity power station may lose synchronism from the remaining generators [1, 3]. To prevent an extension of loss of synchronism to other generators, fast shedding of some generators is an effective measure. The following methods have been proposed so far: A method [3] based on energy function approach; and a method [2] which estimates and predicts the relative swing among generators using data measured on-line at each generator and proposes shedding some generators for stabilization. This method requires a large communication network for an exchange of data between power stations. This paper presents a new stabilizing method and a newly developed stabilizing control system which does not require a large communication network because it utilizes generator output, voltage and current measured on-line in the vicinity of the large-capacity power station. Using these measured data, the system estimates and predicts the relative swing between generators in the large-capacity power station and the remaining generators. Finally, the number of generators to be shed for stabilization is decided and shedding is performed. Configuration and characteristics of the developed stabilizing control system are shown. The validity of this method is confirmed by simulation and testing using an artificial power system.     

Influence of concrete composition on the characterization of fracture surface

An experimental method based on laser triangulation was used to measure the 3-D profile of fracture surface of concrete. The projective-covering method was established to determine the fractal characteristics of fracture surface. Based on the experiment, the influence of composition of concrete on the fractal dimension, including water–binder ratio, maximum aggregate size and aggregate type, was investigated. The variation of fractal dimension with the material composition was also analysed to make further understanding of fracture mechanism of concrete.     

An alternative pathway from hot dry rock to green hydrogen by organic Rankine cycle applications

Some researchers have been focused on electricity generation using thermal energy extraction from HDRs via Organic Rankine cycles. This new research topic creates a new pathway to reach green hydrogen for countries that have geothermal power such as Turkey. In this study, a well in the Nevşehir region that does not has the potential to be used in direct geothermal energy applications due to the absence of water was examined. By using the heat obtained from HDR by injected water, the estimated amount of electricity that can be produced with a single shaft binary organic Rankine cycle was revealed by calculating the thermal energy that can be obtained from the wells which have a surface temperature of 183 °C at 2900 m 2900 m depth. In the next step, the hydrolysis of water with electricity obtained from renewable energy and the hydrogen potential that can be produced were revealed. This hydrogen, which is estimated to be produced, can be fed directly to the natural gas lines or subjected to processes such as storage or industrial usage.     

直喷柴油机喷油系统对燃烧和排放影响的三维模拟研究

直喷柴油机的喷油过程影响燃烧过程、影响发动机性能和污染物排放。为了研究喷油特性(如不同的喷油压力、喷油定时和喷孔直径等)对燃烧性能的影响,利用三维数值模拟软件K IVA-3代码,对喷油过程、燃烧过程和发动机性能进行了数值模拟。计算结果显示了不同喷油特性下的NO和碳烟排放的变化趋势。     

A multi-criteria decision making analysis for feasibility of nanoparticle addition in biohydrogen production enhancement for scaling-up studies

Nanoparticles (NPs) thanks to their unique features such as large surface area, high catalytic activity and intra-cellular electron transfer ability used as an enhancement additive in biohydrogen production. Up to date, inorganic, organic and their mixtures of various NPs were produced from different input sources and synthesis methodology. The NPs properties and cost minimization are the critical factors for the scale up studies of industrial applications. Nevertheless, there have not been any study on the determination of the most efficient and feasible NPs in biohydrogen production for the scaling up the process. In this study, the NPs used for biohydrogen production enhancement over Clostridium sp. by dark fermentation were examined and these studies were evaluated to determine the most effective and feasible NPs using the two-stage TOPSIS method. As a result, iron-containing NPs (hematite, magnetite) were determined as the most effective and economical NPs for increasing the yield.     

Robot Cloud: Bridging the power of robotics and cloud computing

Cloud computing is shaping the cyber world and evolves as a key computing and service platform for sharing resources including platforms, software applications and everything in the form of services. This is known “X as a Service”. Although it brings our age unparalleled computing ability and economic benefits, the application of cloud computing is still limited currently in the cyberspace due to the cloud services can only reside in cloud instead of our daily life environment. In fact, there are still a plethora of physical position based on-site service demands that cloud computing could help little due to the “cyber limitation”. In this paper, we aim to integrate the cyber world and the physical world by bringing up the idea of “Robot Cloud” to bridge the power of robotics and cloud computing. To make it possible, we design a novel Robot Cloud stack to support our idea and adopt the service-oriented architecture (SOA) to make the functional modules in the Robot Cloud more flexible, extensible and reusable. Then we develop a prototype of Robot Cloud using the popular Google App Engine to demonstrate our design method. Finally, we conduct the simulation experiments with a “robot show” application scenario to evaluate our scheduling policy and identify the effect of different request distributions and robot center solutions.     

环氧树脂基含水定形相变材料

以固体石蜡和液体石蜡进行复配制得低熔点石蜡,采用十二烷基苯磺酸钠（SDBS）作表面活性剂,将水分散于低熔点石蜡中,然后加入环氧树脂,制得含水型树脂基定形相变材料。显微分析显示,石蜡和水的包合体在基体中分散均匀,分散的石蜡粒径基本上在10μm以下,包合体中水呈梭型．包合体粒径分布范围窄;相变过程无脱离现象,材料生产成本低,具有良好的应用前景。     

In situ generation of hydrogen peroxide from reaction of O2 with hydroxylamine from hydroxylammonium salt in neutral aqueous or non-aqueous medium using reusable Pd/Al2O3 catalyst

In situ generation of H₂O₂ with high yield can be accomplished by reacting O₂ with NH₂OH from hydroxylammonium salt [NH₂OH · HCl or (NH₂OH)₂ · H₂SO₄] in a neutral aqueous medium using a reusable heterogeneous Pd (1.0 wt%)/Al₂O₃ catalyst, even at low temperature (10 °C), with the formation of harmless by-products (viz. N₂ and water). The presence of KCl or KBr in the medium has beneficial effect. The H₂O₂ generation is strongly influenced by the pH of medium, reaction period and temperature; best results are obtained at the optimum pH and reaction medium.     

Feasibility study of iridium production at ETRR-2

Iridium is a very rare, precious, silvery white, hard, brittle metal that even resists most acids, it is one of the densest substances known on earth (∼22.5 g/cm³). The important radioactive isotope (iridium-192) is produced by neutron irradiations of iridium-191 found in natural iridium. Ir-192 has a half-live of 74 days and is used in industrial radiography and it has many other applications. This work presents a neutronic analysis part of a feasibility study of iridium production in the core central position of ETRR-2. A design of iridium irradiation device is proposed. Monte Carlo simulation of the reactor core with and without Iridium device has been performed. The results showed that the reactivity worth of about 120 g is less than 1200 PCM, which agree with the safety limits of the reactor. Also the heat deposition and power peaking factor have been calculated. Finally, the activity of iridium as a function of irradiation time was calculated.     

Feasibility study of fuel cell-hybrid powertrains in non-road mobile machineries

This paper presents a powertrain feasibility study for a fuel cell-hybrid non-road mobile machinery. The objective is to compare different fuel cell-hybrid powertrain topologies. Different hybrid topologies define the powertrain from a source to loads. The compared properties of different powertrains are weight, size, efficiency, initial cost, and lifetime cost. The paper assesses topologies with different active and passive connections of a battery pack, ultracapacitor pack, or both. The comparison of the topologies needs a validated simulation tool, specific power control algorithms, and detailed knowledge about the target application. The results conclude that fuel cell powertrains buffered with a high-power battery pack yield minimum weight and size. However, minimum lifetime costs are obtained by topologies buffered with an ultracapacitor, which, on the other hand, increase weight and size. Furthermore, there are cost effective buffering combinations of a battery and ultracapacitor in comparison to topologies buffered with a high-energy battery.