A comparison between the algebraic and the reduced order observer approaches for on‐line load torque estimation in a unit power factor rectifier‐DC motor system

In this article, a comparison between the performances of an online algebraic estimator and a reduced order observer is established in the context of adaptive load torque estimation in a controlled unit power factor rectifier‐DC motor system combination. A passivity‐based output feedback controller was constructed to regulate the angular speed while correcting the power factor of the mono phase boost rectifier. The proposed controller allowed us to compare the results of both on‐line estimation techniques. The experimental results show a superiority of the algebraic approach in which the angular velocity was maintained at the desired reference value by the adapted controller, even under severe load changes on the motor shaft, while the power factor was also kept at high values in the power supply system. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Sliding mode control of DC‐to‐DC power converters using integral reconstructors

A sliding mode feedback controller, based on integral reconstructors is developed for the regulation of the ‘boost’ DC‐to‐DC power converter circuit conduction in continuous conduction mode. The feedback control scheme uses only output capacitor voltage measurements, as well as knowledge of the available input signal, represented by the switch positions. The robustness of the feedback scheme is tested with abusively large, unmodelled, sudden load resistance variations. Copyright © 2002 John Wiley & Sons, Ltd.     

Enhanced liquid biofuel production from crude palm oil over synthesized NiMoW-ZSM-5/MCM-41 catalyst

Micro-mesoporous ZSM-5/MCM-41 composites were prepared and then loaded with varied contents of NiMoW by the wet impregnation method. The hydrocracking conversion of crude palm oil to liquid biofuels with the prepared catalysts was carried out in a batch reactor at 400°C for 2 h. ZSM-5/MCM-41 composite exhibited 51.00% conversion with a yield of 9.23% gasoline, 20.60% kerosene, and 21.17% diesel. Upon loading of NiMoW, the catalysts exhibited an improved conversion (≥ 62.60%) and a reduced formation of coke, which resulted from combined properties of ZSM-5 with MCM-41 and the presence of dispersed NiMoW. The contents of impregnated metals also affected the performance of catalysts. Using ANOVA analysis (p < 0.05), we found that 8:8:8 wt.% NiMoW-ZSM-5/MCM-41 catalyst was suitable for the production of biofuels, when considering the efficiency and cost-effectiveness.     

Surface-based and mass spectrometric approaches to deciphering sugar-protein interactions in a galactose-specific agglutinin

Interest in powerful, nanosized tools to analyze in detail glycan-protein interactions has increased significantly over recent years. Here, we report two complementary approaches to characterize such interactions with high sensitivity, low sample consumption, and without the need for sample labeling, namely, surface plasmon resonance (SPR) and an approach that combines limited proteolysis and mass spectrometry. Combination of these two approaches to investigate glycan-protein interactions allows (1) to characterize interactions through kinetic and thermodynamic parameters, (2) to capture efficiently the carbohydrate-binding protein, and (3) to identify the interacted protein and its carbohydrate binding site by mass spectrometry. As a proof of principle, the interaction of the galactose-specific legume lectin Erythrina cristagalli agglutinin with several sugars has been characterized in-depth by means of these two approaches.     

Pd Control For Active Vibration Damping In An Underactuated Nonlinear System

A Lyapunov based control approach is proposed for the specification of the constant gains of an asymptotically stabilizing Proportional‐Derivative (PD) controller, devised to damp the oscillations of an underactuated nonlinear mechanical system. The system consists of a rigid beam, sliding on the interior of a spherical surface, and an actuated cart, located over the beam, which acts as an active vibration damping element.     

Reviewing 25 Years of Testing Technique Experiments

Mature knowledge allows engineering disciplines the achievement of predictable results. Unfortunately, the type of knowledge used in software engineering can be considered to be of a relatively low maturity, and developers are guided by intuition, fashion or market-speak rather than by facts or undisputed statements proper to an engineering discipline. Testing techniques determine different criteria for selecting the test cases that will be used as input to the system under examination, which means that an effective and efficient selection of test cases conditions the success of the tests. The knowledge for selecting testing techniques should come from studies that empirically justify the benefits and application conditions of the different techniques. This paper analyzes the maturity level of the knowledge about testing techniques by examining existing empirical studies about these techniques. We have analyzed their results, and obtained a testing technique knowledge classification based on their factuality and objectivity, according to four parameters.     

Gelatin hydrolysate powder from the scales of spotted golden goatfish: Effect of drying conditions and juice fortification

Effects of different spray drying temperatures (inlet temperatures of 160, 180, and 200°C) on characteristics, bioactivity, and sensory properties of gelatin hydrolysate from spotted golden goatfish scales using maltodextrin as a carrier agent were investigated. The yield of gelatin hydrolysate powder was higher, when inlet temperature increased (p?p?p?p?相似文献   

Sliding Mode ∑‐Δ Modulation Control of the Boost Converter

A switched implementation of average dynamic output feedback laws trough a ∑‐Δ‐modulator, widely known in the classic communications and analog signal encoding literature, not only frees the sliding mode control approach from state measurements and the corresponding synthesis of sliding surfaces in the plant's state space, but it also allows to effectively transfer all desired closed loop features of an uniformly bounded, continuous, average output feedback controller design into the more restrictive discrete‐valued (ON‐OFF) control framework of a switched system. The proposed approach is here used for the input‐output sliding mode stabilization of the “boost” DC‐to‐DC converter. This is achieved by means of a well known passivity based controller but any other output feedback design would have served our purposes. This emphasizes the flexibility of the proposed sliding mode control design implementation through ∑‐Δ‐modulators.     

DC‐to‐AC power conversion on a ‘boost’ converter

In this article, we provide an approximate sliding mode control‐based solution to the DC–AC power conversion problem on a ‘boost’ converter. The approach uses the flatness property of the system as a pivot for generating a sequence of minimum phase output reference trajectory candidates. The generated candidates are obtained as differential parameterizations of the minimum phase inductor current variable in terms of the non‐minimum phase desired output capacitor voltage. The associated residual dynamics of the ideal sliding motions is shown to reasonably approximate the desired biased sinusoidal output capacitor voltage signal. Copyright © 2001 John Wiley & Sons, Ltd.