Miracle-dz/UniFAR-FTUs huggingface dataset:
Concept for a Combustion System in Oxyfuel Gas Turbine Combined Cycles

A promising candidate for CO2 neutral power production is semiclosed oxyfuel combustion combined cycles (SCOC-CC). Two alternative SCOC-CCs have been investigated both with recirculation of the working fluid (WF) (CO2 and H2O) but with different H2O content due to different conditions for condensation of water from the working fluid. The alternative with low moisture content in the recirculated working fluid has shown the highest thermodynamic potential and has been selected for further study. The necessity to use recirculated exhaust gas as the working fluid will make the design of the gas turbine quite different from a conventional gas turbine. For a combined cycle using a steam Rankine cycle as a bottoming cycle, it is vital that the temperature of the exhaust gas from the Brayton cycle is well-suited for steam generation that fits steam turbine live steam conditions. For oxyfuel gas turbines with a combustor outlet temperature of the same magnitude as conventional gas turbines, a much higher pressure ratio is required (close to twice the ratio as for a conventional gas turbine) in order to achieve a turbine outlet temperature suitable for combined cycle. Based on input from the optimized cycle calculations, a conceptual combustion system has been developed, where three different combustor feed streams can be controlled independently: the natural gas fuel, the oxidizer consisting mainly of oxygen plus some impurities, and the recirculated working fluid. This gives more flexibility compared to air-based gas turbines, but also introduces some design challenges. A key issue is how to maintain high combustion efficiency over the entire load range using as little oxidizer as possible and with emissions (NOx, CO, unburnt hydrocarbons (UHC)) within given constraints. Other important challenges are related to combustion stability, heat transfer and cooling, and material integrity, all of which are much affected when going from air-based to oxygen-based gas turbine combustion. Matching with existing air-based burner and combustor designs has been done in order to use as much as possible of what is proven technology today. The selected stabilization concept, heat transfer evaluation, burner, and combustion chamber layout will be described. As a next step, the pilot burner will be tested both at atmospheric and high pressure conditions.
Rendezvous

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Planar antenna excited by electromagnetically coupled coplanar waveguide

Planar antennas fed by electromagnetically coupled coplanar waveguide (CPW) have been fabricated on a single layer substrate with various thicknesses, and been studied experimentally. To suppress the spurious mode due to the parallel plate structure in the antenna system, short pins are inserted near the feeding point of the coplanar line. The measurement results of this antenna demonstrated high performance in both return loss and radiation pattern.
In-Depth Research Information Differential Method of Measurement

With the development of automation and communication technology, measurement information is widely used in various industrial, agricultural, commercial, and other living. At present, the problems exist in the accuracy and time synchronization of the measurement information. That brings the difficulty for data analysis and decision making. This paper starts from the existing measurement information, in-depth analyses the root cause, puts forward the measurement information of differential method, the effect of practical application in electric power system by measuring the differential method of information So as to determine the role of differential measurement method of information and promotion value, provide strong support for the rapid development of automation information technology.
Heterogeneity Influence on Electric Field Induced Piezoelectric Microfracture

Spatial variations in piezoelectric material properties can influence localized residual stresses under electro-mechanical loading, which has been shown to contribute to microfractures (Jiang, Q., Subbarao, E.C. and Cross, L.E. 1994. ''Grain Size Dependence of Electric Fatigue Behavior of Hot Pressed PLZT Ferroelectric Ceramics,'' Acta Metall. Mater., 42(11):3687–3694; Lynch, C.S. 1998. ''Fracture of Ferroelectric and Relaxor Electro-ceramics: Influences of Electric Field,'' Acta Mater. , 46(2):599–608; Wang, Z. , Jiang, Q. , White, G.S. and Richardson, A.K. 1998. ''Processing Flaws in PZT Transducer Rings,'' Smart Mater. Struct. , 7:867–873). The effect of residual stress on piezoelectric microfracture has been modeled by introducing a crack at the edge of a piezoelectric elliptic inclusion with dissimilar piezoelectric matrix material properties. Piezoelectric weight functions were used to assess changes in intensity factors and energy release rates when an inclusion is present. The shape of the elliptic inclusion is shown to have an effect on local driving forces. Additionally, comparison of impermeable and permeable crack face boundary conditions illustrate the importance of applying the more 'physical' permeable conditions to achieve positive flaw-localized driving forces under electrical loading.
An Inductorless Cascaded Phase-Locked Loop with Pulse Injection Locking Technique in 90 nm CMOS

An inductorless phase-locked loop with subharmonic pulse injection locking was realized (PLL area: 0.11 mm2) by adopting 90 nm Si CMOS technology. The proposed circuit is configured with two cascaded PLLs; one of them is a reference PLL that generates reference signals to the other one from low-frequency external reference signals. The other is a main PLL that generates high-frequency output signals. A high-frequency half-integral subharmonic locking technique was used to decrease the phase noise characteristics. For a 50 MHz input reference signal, without injection locking, the 1 MHz offset phase noise was −88 dBc/Hz at a PLL output frequency of 7.2 GHz (= 144 × 50 MHz); with injection locking, the noise was −101 dBc/Hz (spur level: −31 dBc; power consumption from a 1.0 V power supply: 25 mW).
Dragon Ears airborne acoustic array: CSP analysis applied to cross array to compute real-time 2D acoustic sound field

This paper describes development and application of a novel method to accomplish real-time solid angle acoustic direction finding using two 8-element orthogonal microphone arrays. The developed prototype system was intended for localization and signature recognition of ground-based sounds from a small UAV. Recent advances in computer speeds have enabled the implementation of microphone arrays in many audio applications. Still, the real-time presentation of a two-dimensional sound field for the purpose of audio target localization is computationally challenging. In order to overcome this challenge, a crosspower spectrum phase1 (CSP) technique was applied to each 8-element arm of a 16-element cross array to provide audio target localization. In this paper, we describe the technique and compare it with two other commonly used techniques; Cross-Spectral Matrix2 and MUSIC3. The results show that the CSP technique applied to two 8-element orthogonal arrays provides a computationally efficient solution with reasonable accuracy and tolerable artifacts, sufficient for real-time applications. Additional topics include development of a synchronized 16-channel transmitter and receiver to relay the airborne data to the ground-based processor and presentation of test data demonstrating both ground-mounted operation and airborne localization of ground-based gunshots and loud engine sounds.
Tensile Strength Prediction of Out-of-Plane Composite Joints for Integrated Composite Cabins

The failure of an adhesive-bonded and bolted composite joint under axial tensile loading is investigated. A progressive damage model consisting of a three dimensional FEM accompanying with a three dimensional maximum stress failure criterion and corresponding material degradation model is established to predict the failure behavior of the joint. The predicted failure load and load-displacement curve are validated by the experimental results is obtained. Moreover, the result shows that the discontinuity between two L-shaped laminates is the weak spot and required to be strengthened.
Improved Equivalent Resistance Method for Low-Voltage Distribution Line Loss Calculation

Aiming at the insufficiency of Equivalent Resistance Method for a low-voltage distribution line loss calculation, this article has been improved. Then this paper presents the method of using three-phase quantity of electricity to calculate three-phase current, it can calculate the three-phase unbalanced line loss without current date and facilitate the application of Three-phase Unbalanced Method. It develops our own program based on Visio to calculate low-voltage distribution line loss. The results showed: Improved Equivalent Resistance Method improves the accuracy; in the three-phase unbalanced the method of using three-phase quantity of electricity to calculate three-phase current is more easily modified and more practical value.
Development of a superconducting undulator for the APS

As the western hemisphere's premier x-ray synchrotron radiation source, the Advanced Photon Source (APS) continues to advance the state of the art in insertion device technology in order to maintain record high brightness, especially in the hard x-ray wavelength region. Due to the unique bunch pattern used for normal APS operations and its ultimate capabilities, the APS has chosen superconducting technology for its future hard x-ray undulator sources. In the last several years, the APS in collaboration with the Budker Institute of Nuclear Physics has being developing the technology for planar, small-period superconducting undulators (SCUs). These developments include the design and construction of several prototypes and the construction of the necessary mechanical, vacuum, and cryogenic infrastructure at the APS site. Several prototypes of the SCU magnetic structure have been built and tested. The first SCU is assembled and will be installed in the APS storage ring at the end of 2012. Expected SCU performance in terms of x-ray brightness should noticeably exceed that of existing APS undulators. Immediately after commissioning, the SCU will be used at APS Sector 6 as the radiation source for high-energy x-ray studies.
A dual‐band Chebyshev impedance transformer

This paper presents a simple extension of the Chebyshev quarter‐wave multisection transformer synthesis to dual‐band operation. The method is a variation of the classical Chebyshev transformer design procedure, using a suitable 2nd‐order trigonometric polynomial as the argument of the Chebyshev polynomial. As compared to a single‐band Chebyshev transformer encompassing both required passbands, the proposed design yields significantly better performance. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 141–145, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11151
Axial Bladeless Turbine Suitable for High Supersonic Flows

The development of future propulsion systems, targeting superior efficiencies with ultra compact designs, may rely on the extraction of power from high supersonic flows. In conventional supersonic turbines operating under such extreme flow conditions, the presence of airfoils induces important flow perturbations that originate severe aerodynamic losses while restricting the operating range due to starting issues. These limitations represent design opportunities for bladeless turbines.The present paper documents for the first time in the open literature an axial bladeless turbine concept, able to extract mechanical power from high supersonic flows through an annular channel. The tangential drag force exerted by the viscous supersonic flow on the rotating inner and outer endwalls produce power, with enhanced simplicity, coolability, manufacturability, and maintainability. Reynolds Averaged Navier-Stokes simulations allowed the detailed evaluation of the aerodynamic performance of the bladeless configuration. The present unconventional axial turbine concept becomes an exceptional design choice when one seeks to extract certain amount of power from supersonic flows with minimum pressure losses.Copyright © 2014 by ASME
Modeling critical failures maintenance: a case study for mining

Purpose – This paper aims to present a case study where computer simulation is used to evaluate maintenance strategies targeted to cope with a critical failure of a repairable system.Design/methodology/approach – The problem is characterized, modeled and simulated under different conditions and for finite time periods. The different states of the system and the possible transitions among these states are characterized. Transitions are conditioned by the failure dynamics and by the maintenance decision maker. The model is then formalized and the data requirements fulfilled.Findings – The performance of several maintenance policies based on educated estimations about the equipment behavior, manufacturer recommendations, well‐known previous maintenance practices, etc. benchmarked against the results of certain modeling and optimization tools.Practical implications – Practical implications of this work have to do with following the entire modeling process and maintenance policy assessment with an engineering .
The Influence of International Dispersed vs. Home-Based R&D on Innovation Performance

Recent years have shown a surge of firms globalising their innovation activities in order to gain from international knowledge. This paper evaluates this strategy by investigating whether firms with international R&D are more innovative than firms doing R&D only in their home country. One main novelty is that we shed light on two competing hypotheses whether stronger dispersed international R&D activities hamper or stimulate innovation. Second, we employ two well-established market-based indicators for innovation (introduction of and sales growth rates due to new products) instead of looking at inventions (patents). Using German CIS data for about 2100 firms, the econometric results show that firms with international R&D are more likely to launch new products (firm and market novelties) than firms with home-based R&D only. They are also more successful in terms of higher sales growth with firm novelties. However, given the introduction of a market novelty, the location of R&D doesn’t matter for the sales growth with market novelties. The results concerning the degree of R&D internationalisation are mixed: The likelihood of introducing firm novelties increases with a stronger dispersion of foreign R&D activities (for market novelties only up to a specific point). The relationship between degree of R&D internationalisation and innovation success turns out to be inverse u-shaped.
Particle swarm against market-based optimisation for obstacle avoidance

A comparison of particle swarm optimisation (PSO) and market-based optimisation (MBO) is presented when applied to obstacle avoidance by mobile robots using artificial potential fields and special traffic rules. Most notably, PSO and MBO are applied to optimise the motion of mobile robots when acting in a common confined workspace. Simulation results show that both methods perform equally well with slight advantage for PSO.
Sustainability Ranking of the Iranian Major Ports by Using MCDM Methods

The maritime industry is moving towards a sustainable supply chain (SSC), intending to increase the quality of logistics and make more profit. The sustainability of the maritime supply chain (MSC) in Iran is one of the topics that has not been widely studied. Ports play a crucial role in promoting Iran’s position in the international transit of products, strengthening economic, social, and environmental connections with neighboring eastern and northeastern countries, improving GDP, and promoting the role of the free zone in the national development of the country. Port development is one of the essential elements in the government’s strategic planning in developing and activating the East axis. It has a special priority in line with government policies based on deprivation elimination and improving people’s living standards. This paper considers five significant ports of Iran that are part of special economic zones and studies the sustainability of those ports. In this research, different multi-criteria decision-making methods were applied to solve a sustainability-ranking problem of major Iranian ports. First of all, by using the SWARA method, sub-criteria of loading and unloading oil, pier length, and population obtained the highest scores in economic, environmental, and social aspects of sustainability, respectively, which shows that they had the greatest impact on the sustainability assessment of Iranian ports. Finally, the MARCOS and CoCoSo techniques were the most similar in all three dimensions of sustainability, and both seemed to be suitable methods for evaluating the sustainability of ports. Furthermore, the implementation of sensitivity analysis and definition of different scenarios for port evaluation and the high efficiency of the MARCOS method were determined in solving the port-ranking problem. According to the MARCOS method results, economic, environmental, and social criteria were all effective criteria in the sustainable development of major Iranian ports and have been largely applied in Astara, Bushehr, and Imam Khomeini ports. Based on the analysis of the results, several managerial insights to make better industry decisions are also revealed.
Electromechanical finite element modelling for dynamic analysis of a cantilevered piezoelectric energy harvester with tip mass offset under base excitations

A new electromechanical finite element modelling of a vibration power harvester and its validation with experimental studies are presented in this paper. The new contributions for modelling the electromechanical finite element piezoelectric unimorph beam with tip mass offset under base excitation encompass five major solution techniques. These include the electromechanical discretization, kinematic equations, coupled field equations, Lagrangian electromechanical dynamic equations and orthonormalized global matrix and scalar forms of electromechanical finite element dynamic equations. Such techniques have not been rigorously modelled previously by other researchers. There are also benefits to presenting the numerical techniques proposed in this paper. First, the proposed numerical techniques can be used for applications in many different geometrical models, including micro-electro-mechanical system power harvesting devices. Second, applying tip mass offset located after the end of the piezoelectric beam length can result in a very practical design, which avoids direct contact with piezoelectric material because of its brittle nature. Since the surfaces of actual piezoelectric material are covered evenly with thin conducting electrodes for generating single voltage, we introduce the new electromechanical discretization, consisting of the mechanical and electrical discretized elements. Moreover, the reduced electromechanical finite element dynamic equations can be further formulated to obtain the series form of new multimode electromechanical frequency response functions of the displacement, velocity, voltage, current and power, including optimal power harvesting. The normalized numerical strain node and eigenmode shapes are also further formulated using numerical discretization. Finally, the parametric numerical case studies of the piezoelectric unimorph beam under a resistive shunt circuit show good agreement with the experimental studies.
Method for Analyzing Field Scale Surface Irrigation Uniformity

This paper presents a method for describing and evaluating some of the major factors that cause nonuniformity in surface irrigation systems. Methods including the following are presented for statistically combining these effects: variations in opportunity times (e.g., caused by nonparallel advance and recession curves), variations in soil infiltration properties, variations in land grading, and variations in advance rates. A simulation model is used to test the derived equations for a typical example.
Challenges in the application of anthropometric measurements

Traditional anthropometry is characterized by measuring distances, circumferences and weights. All these values are one-dimensional. A further area of anthropometric research is measuring of human forces. These values must also be indicated as one-dimensional measures. All the called values show, according to the human variability, various distributions. In order to simplify the indication of this distribution, the 5th, 50th and 95th-percentiles are shown in the most anthropometric tables. By the introduction of computer technology, it becomes possible to create three-dimensional representatives of the human body called soft-dummies. The dimensions of these dummies, however, are always based on the one-dimensional level of the traditional measurements. In the last few years, however, new scanner technologies were shown by which a three-dimensional description of the body surface is possible. By this technique, a very dense list of three-dimensional points is created. The position of these points depends on the arbitrary relation between the body to be measured and the position of the scanning system. That means that the measured points are not functionally related to a certain body point. So, it is not possible to carry out statistical analysis over these points. If, however, a soft-dummy is blown up in the shape defined by these scanner points, the parameters by which the dummy is described may be used for statistical analysis. This is really a new form of anthropometric measurement and application, which will get increasing importance in the future. With dummies, new additional abilities may be simulated. For instance, the dummy can be provided with forces, the dummy can be animated and so show movements, and the dummy can have contact with the virtual surfaces of a CAD-world and should show responsible deformations. For all these cases, new anthropometric data are necessary which jump over the border of traditional anthropometry. In order to pick up these measures, new measuring systems must be developed. Three-dimensional force measuring equipment must be developed. Movement can be measured by the triangulation of markers. That is an introduced and established technique. However, in many test situations and, especially, in real life these markers obstruct the freedom of movement. Thus, new contact-less techniques must be developed in order to satisfy this demand. Also, the contact between body and surface (especially seats) must be investigated in a soft-dummy related manner. In order to use all these new data, a mathematical modelling is necessary, by which a prediction in situations which are unknown during the investigation phase is possible. A further advantage for the designer is the reproductive behaviour of the soft-dummy is opposite to a real person. By such a technique, the experience with living subjects is not refused, but the first approach will be much more human related than is possible on the basis of the present data material.