A mission synthesis algorithm for fatigue damage analysis

This paper presents a signal processing based algorithm, the Mildly Nonstationary Mission Synthesis (MNMS), which produces a short mission signal from long records of experimental data. The algorithm uses the Discrete Fourier Transform, Orthogonal Wavelet Transform and bump reinsertion procedures. In order to observe the algorithm effectiveness a fatigue damage case study was performed for a vehicle lower suspension arm using signals containing tensile and compressive preloading. The mission synthesis results were compared to the original road data in terms of both the global signal statistics and the fatigue damage variation as a function of compression ratio. Three bump reinsertion methods were used and evaluated. The methods differed in the manner in which bumps (shock events) from different wavelet groups (frequency bands) were synchronised during the reinsertion process. One method, based on time synchronised section reinsertion, produced the best results in terms of mission signal kurtosis, crest factor, root-mean-square level and power spectral density. For improved algorithm performance, bump selection was identified as the main control parameter requiring optimisation

A mission synthesis algorithm for editing variable amplitude fatigue signals

This paper presents a wavelet-based fatigue data editing algorithm, known as Wavelet Bump Extraction (WBE), to summarise long record of fatigue loadings. The key point of this algorithm is to produce a shorter time history (mission signal) that retains the majority of the original fatigue damage whilst preserving cycle sequence information. In WBE, features or bumps are identified in characteristic frequency bands using the Daubechies’ wavelet transform. Comparison of the fatigue life between the original and mission signals was performed to validate the algorithm. The fatigue life was predicted using a variable amplitude fatigue damage model and the results showed a good correlation between the damage caused by the original and mission signals. Finally, the findings suggest that WBE is a suitable approach for producing a shortened mission signal for accelerated fatigue testing

Application of neural network observer for on-line estimation of salient-pole synchronous generators' dynamic parameters using the operating data

Parameter identification is critical for modern control strategies in electrical power systems which is considered both dynamic performance and energy efficiency. This paper presents a novel application of ANN observers in estimating and tracking Salient-Pole Synchronous Generator Dynamic Parameters using time-domain, on-line disturbance measurements. The data for training ANN Observers are obtained through off-line simulations of a salient-pole synchronous generator operating in a one-machine-infinite-bus environment. The Levenberg-Marquardt algorithm has been adopted and assimilated into the back-propagation learning algorithm for training feed-forward neural networks. The inputs of ANNs are organized in conformity with the results of the observability analysis of synchronous generator dynamic parameters in its dynamic behavior. A collection of ANNs with same inputs but different outputs are developed to determine a set of the dynamic parameters. The ANNs are employed to estimate the dynamic parameters by the measurements which are carried out within each kind of fault separately. The trained ANNs are tested with on-line measurements to identify the dynamic parameters. Simulation studies indicate the ANN observer has a great ability to identify the dynamic parameters of salient-pole synchronous generator. The results also show that the tests which have given better results in estimation of each dynamic parameter can be obtained

Green tea polyphenol-reduced graphene oxide: derivatisation, reduction efficiency, reduction mechanism and cytotoxicity

This paper reports on the derivatisation, reduction efficiency, reduction mechanism and cytotoxicity of green tea polyphenol-reduced graphene oxide (GTP-RGO). The reduction of graphene oxide (GO) at 90°C using a weight ratio (WR) of GTP/GO=1 resulted in the production of a stable GTP-RGO dispersion in aqueous media, as indicated by the results of ultravioletvisible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and the measurement of zeta potential and electrophoretic mobility. In addition, the results from UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis indicated the comparable reduction ability of GTP relative to the standard reducing agent, hydrazine (N2H4). The removal mechanism of epoxy group from GO via reduction reaction with GTP was investigated by implementing hybrid functional method of Becke-3-parameters-Lee-Yang-Parr (B3LYP)using Gaussian 09 software. The energy and frequency calculations showed that the GO reduction using GTP was more spontaneous and relatively took place faster than the reduction using N2H4, as evidenced by higher entropy change (ΔS) (0.039 kcal/mol·K) and lower Gibbs free energy (ΔG) barrier (58.880 kcal/mol).The cytotoxicities of GO and GTP-RGO samples were evaluated against human colonic fibroblasts cells (CCD-18Co). The GO sample was determined to be toxic even at low concentration (6.25 μg/mL), while the GTP-RGO sample possesses notably low toxicity at the same concentration. The cell culture experiments revealed that the incorporation of GTP led to a decrease in the toxicity of GTP-RGO samples

The Use of Antihypertensive and Antiplatelet Drugs on Hospital Stroke Patients

Medicine is one of the most important part of the healing process, the restoration of health and prevention of disease. This study aims to describe the use of drugs, particularly antihypertensive and antiplatelet drugs in stroke patients hospitalized in PKU Muhammadiyah Hospital Bantul during December 2014-April 2015. This research is observational descriptive study. Data collection was done prospectively with a survey of stroke patients in inpatient Al-Insan and al-A'raaf wards in PKU Muhammadiyah Hospital Bantul during the specified period. During the study there were 61 stroke patients sampled in the study, of which 41 (67.2%) were geriatrics and 20 (32.8%) were not geriatrc. From the data, 28 (45.9%) patients did not receive antihypertensive drugs, only 33 (54,1%) patients received antihypertensive drug.The antihypertensive drugs type were given to patients were ACEI 9 (14.8%) and CCB 6 (9.8%), as well as combinations ACEI and CCB 7 (11.5%). Most patients did not receive antiplatelet 43 (70.5%), whereas patients receiving antiplatelet drugs most was the kind of aspirin 17 (27.9%). From the above data it can be concluded that the use of antihypertensive drugs in stroke patients in the inpatient ward in PKU Muhamaddiyah Hospital Bantul quite frequently used, while the use of antiplatelet drugs in these cases rarely used

Penerapan Strategi Pembelajaran Aktif Rotating Trio Exchange (Rte) Disertai Media Question Box Dapat Meningkatkan Prestasi Belajar Siswa pada Pokok Bahasan Laju Reaksi di Kelas XI IPA SMA Negeri 2 Pekanbaru

This study aimed at investigating the significant difference of students\u27 learning achievement between students taught using Rotating Trio Exchange(RTE) assisted with question box and students taught conventionally with question box in chemistry subject at SMAN 2 Pekanbaru. Subject of this research were students at XI MIA 3 as experiment class and XI MIA 1 as control class were randomely selected. Data analized after giving pretest and postest to each class by using ttest. The results revealed that application active learning strategy of RTE was capable to improve student\u27s achievement in chemistry especially in Reaction Rate Subject at 11th SMAN 2 Pekanbaru. The result of the study shows a significant difference of students\u27 learning achievement between students taught using RTE assisted with questions box and students taught conventionally with question box with tobserved 3,87 > ttabel 1,67. And n-gain score for exsperiment class is 0.65 and control class is 0.47, means the improvement of both classes achievement was in average category