Two-step Design of Critical Control Systems Using Disturbance Cancellation Integral Controllers

An efficient critical control system design is proposed in this paper.The key idea is to decompose the design problem into two simpler design steps by the technique used in the classical loop transfer recovery method (LTR).The disturbance cancellation integral controllcr is uscd as a basic controller.Since the standard loop transfer recovery method cannot bc applied to the disturbance cancellation controller, the nonstandard version recently found is used for the decomposition.Exogenous inputs with constraints both on the amplitude and rate of change are considered. The majorant approach is taken to obtain the analytical sufficient matching conditions.A numerical design example is presented to illustrate the effectiveness of the proposed design.     

Accumulative channel-die compression bonding (ACCB): A new severe plastic deformation process to produce bulk nanostructured metals

This paper introduces a new severe plastic deformation process to produce bulk nanostructured metals: accumulative channel-die compression bonding (ACCB). In the ACCB process, which can be applied to thick billets, the procedure of cutting, stacking and compression bonding in a channel-die is repeated to provide an ultrahigh plastic strain. This process was trialed with high purity aluminum. A fully recrystallized aluminum sample was deformed by ACCB at room temperature for up to 10 cycles, corresponding to an equivalent strain of 8.0. The initially coarse grains were subdivided by deformation-induced high-angle boundaries, and the fraction of such high-angle boundaries increased with increasing strain. Several cycles of ACCB led to a quite uniform ultrafine structure dominated by high-angle grain boundaries. The average boundary spacing of the 10-cycles ACCB sample was as small as 690 nm. The maximum ultimate tensile strength of the ACCB samples was 130 MPa after 5 cycles. Further ACCB cycles, however, led to a slight decrease in strength due to enhanced recovery and boundary migration during the deformation process. It has been demonstrated that the ACCB process can be used to produce bulk nanostructured metals of relatively large dimensions. The results suggest that the ACCB process is equivalent to conventional rolling deformation at high strains.     

Wet oxidation of lignin model compounds and acetic acid production

To investigate the wet oxidation (WO) pathways of acetic acid production from lignin, 2-methoxyphenol, 2,6-dimethoxyphenol, and phenol, as lignin model compounds were oxidized in a batch reactor at a temperature of 300°C, residence times of 10–60 seconds and oxygen supplies of 50–100%. Oxidation experiments using major intermediate products in WO of lignin model compounds, as reactants were also performed.Based on the intermediate products identified by GC/MS and HPLC, WO pathways of lignin model compounds are discussed. Acetic acid production by WO of lignin model compounds is also discussed. It was found that the yield of acetic acid for lignin model compounds was lower, at about 9%. The reason that lignin model compounds cannot produce a large amount of acetic acid may be contributed to the fact that the oxidation of phenols easily forms unsaturated dicarboxylic acids with 4 carbon atoms, which cannot produce a large amount of acetic acid. However, saturated dicarboxylic acids and glutaconic acid can produce a higher yield of acetic acid. Therefore, it is possible to increase the yield of acetic acid from lignin by controlling reaction pathways to increase the formation of saturated dicarboxylic acids and glutaconic acid.     

Infrared Microscopy for Examination of Structure in Spray-Dried Granules and Compacts

Novel infrared microscopy has been developed to improve the liquid-immersion method, which is a technique that has been developed by the authors to study the packing structures of powder particles in ceramic green bodies. This paper demonstrates the high potential of the novel technique by presenting clear structures of Si₃N₄ powder granules and their compacts.     

Development of a time‐synchronized wireless sensor network

Network‐based wireless sensing has become an important area of research and various new applications for remote sensing are expected to emerge. One of the promising applications is structural health monitoring of buildings or civil engineering structures, which often requires vibration measurement. For vibration measurement via a wireless network, time synchronization is indispensable. In this paper we introduce a newly developed time‐synchronized wireless sensor network system. The system employs an IEEE 802.11 standard‐based TSF counter and sends the measured data with the counter value. It makes possible consistency on a common clock among different wireless nodes. We describe the accuracy evaluation by simulation studies as the size of the nodes is increased. The hardware and software specifications of the developed wireless system are presented. The experiments were conducted in a three‐story reinforced concrete building and the results showed that the system performance significantly exceeds requirements. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(4): 46–53, 2010; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21020