The comparison of power capability between towed kite and horizontal axis fan

Airborne Wind Energy (AWE) mainly collects wind energy by tethered aircraft at a certain altitude. This paper discusses the recent development of AWE. The actuator disc theory is adopted to consider the influence of kites on wind flow obstruction. The difference of working mode between a horizontal-axis wind turbine (HAWT) and a crosswind kite power systems (CKPS) is compared, the power limit of HAWT and CKPS is calculated, and the reason of the limit power is analyzed. It is pointed out that CKPS has a wider range of flight and should be further analyzed and calculated rather than simply generalized by the system disk theory.

A Comparative Analysis of Disk Scheduling Algorithms

In an operating system, disk scheduling is the process of managing the I/O request to the secondary storage devices such as hard disk. The speed of the processor and primary memory has increased in a rapid way than the secondary storage. Seek time is the important factor in an operating system to get the best access time. For the better performance, speedy servicing of I/O request for secondary memory is very important. The goal of the disk-scheduling algorithm is to minimize the response time and maximize throughput of the system. This work analyzed and compared various basic disk scheduling techniques like First Come First Serve (FCFS), Shortest Seek Time First (SSTF), SCAN, LOOK, Circular SCAN (C-SCAN) and Circular LOOK (C-LOOK) along with the corresponding seek time. From the comparative analysis, the result show that C-LOOK algorithm give the least head movement and seek time in different cases as compared to other algorithm. Therefore, it maximizes the throughput for the storage devices.

Mechanical Design in an Interdisciplinary Predesign Tool

Within the conceptual design phase of an aero engine parametric studies — taking into account all interdisciplinary disciplines — are carried-out in order to find an optimum engine. MOPEDS (Modular Performance and Engine Design System) is MTU’s predesign tool and is used for these tasks. The already existing methods of MOPEDS are expanded by using and implementing additional tools for a first component mechanical design, thus enabling a “zooming” capability for individual methods. The presented paper describes how these tools are combined in order to achieve a first mechanical design of turbo components already in the conceptual design phase. Based on the performance calculation and a life target, the allowable stresses and temperatures are calculated. Based on the life requirement and the translated temperature and stress limits, the first design of the components is carried out. For complicated geometries such as the blade-root, sophisticated methods are used. Additionally, topology based methods, based on the statistical analysis of existing aero engine geometries, are used for the first design of small elements (outer shroud, inner shroud, rotating air system, disk-wings). The application and the accuracy of the methods are shown in various studies. This approach leads to a first component design of high accuracy in a short time.

An Approach to Calculate the Elastic Interaction Energy of Inhomogeneous Precipitates: Application to γ′-Ni3Ti in A-286 Steel

The elastic interaction energy between several precipitates is of interest since it may induce ordering of precipitates in many metallurgical systems. Most of the works on this subject assumed homogeneous systems, namely, the elastic constants of the matrix and the precipitates are identical. In this study, the elastic fields, and self and interaction energies of inhomogeneous anisotropic precipitates have been solved and assessed, based on a new iterative approach using the quasi-analytic Fourier transform method. This approach allows good approximation for problems of several inhomogeneous precipitates in solid matrix. We illustrate the calculation approach on γ′-Ni3Ti precipitates in A-286 steel and demonstrate that the influence of elastic inhomogeneity is in some incidences only quantitative, while in others it has essential effect. Assuming homogeneous system, disk shape precipitate is associated with minimum elastic energy. Only by taking into account different elastic constants of the precipitate, the minimum self-energy is found to be associated with spherical shape, and indeed, this is the observed shape of the precipitates in A-286 steel. The elastic interaction energy between two precipitates was calculated for several configurations. Significant differences between the interactions in homogeneous and inhomogeneous were found for disk shape morphologies. Only quantitative differences (9% higher interaction between inhomogeneous precipitates) were found between two spherical precipitates, which are the actual shape.

Mechanical Properties of Graphene Oxide–Copper Composites

Due to their characteristics, sintered Cu-C composites are materials used in electrical equipment. These characteristics include high electrical conductivity, thermal conductivity and excellent resistance to abrasion. Currently, graphite nanopowder is used successfully as a carbon material. Metal-graphite, which is created on its basis, exists in different proportions of graphite to metal. A larger graphite content has a positive effect on smaller wear of commutators and rings. In contrast, a material with a higher copper content is used at high current densities. An example of such machines is a DC motor starter characterized by low voltage and large current. Tribological properties of Cu-C composites depend on the form of carbon they include. Owing to the capability to manufacture graphene, it has become possible to produce composites with its content. The present study tested the effect of a graphene oxide content on tribological properties in contact with steel. Tests were conducted on a ball-on-disk apparatus in conditions of dry friction. Microscopic observation was performed on the Hitachi SU70 field emission electron microscope. EDS analyses were performed using the Thermo Scientific X-ray Microanalysis system. Disk wear and surface geometrical structure parameters (SGP) of the samples after tribological tests were determined on the basis of measurements made on the Talysurf 3D contact profilometer from Taylor Hobson.

Turbine Rotor Disk Health Monitoring Assessment Based on Sensor Technology and Spin Tests Data

The paper focuses on presenting data obtained from spin test experiments of a turbine engine like rotor disk and assessing their correlation to the development of a structural health monitoring and fault detection system. The data were obtained under various operating conditions such as the rotor disk being artificially induced with and without a notch and rotated at a rotational speed of up to 10,000 rpm under balanced and imbalanced state. The data collected included blade tip clearance, blade tip timing measurements, and shaft displacements. Two different sensor technologies were employed in the testing: microwave and capacitive sensors, respectively. The experimental tests were conducted at the NASA Glenn Research Center’s Rotordynamics Laboratory using a high precision spin system. Disk flaw observations and related assessments from the collected data for both sensors are reported and discussed.

Research of Disk Operating Technique in UEFI Shell Environment

This paper describes the theory and method of programming under the environment of UEFI Shell and also introduces the UDK2010.UP4 install and configuration. The program run in UEFI Shell can get EFI Boot Services through the EFI_SYSTEM_TABLE parameter, after this it can operate disk files through Simple File System Protocol and EFI File Protocol. The work in this paper mainly introduces some file operations in UEFI Shell, such as file creating, data access on a FAT file system disk through a UEFI Application (UEFI App hereafter).

Hospital Information System Performance Optimization

Study the issue of hospital information performance, improve hospital information management efficiency. For the issue of hospital information system disk competition, high-speed buffers and low hit rate shared pool, resulting in the problem of long time user waiting, low efficient system support for system throughput, optimization improvement for hospital information systems. First, to optimize the architecture of the database, and then rationally design system global area, disk I / O and connection pool etc in the memory area, finally reasonably organize the SQL statement. Apply to the optimized hospital information system into the Medical, example shows that optimized hospital information system improved system throughput, reduced the user waiting time, and greatly improved the operation efficiency of Medical College.