Recent Patents on Engineering - Volume 4, Issue 2, 2010

Optical duobinary signal has narrow spectrum, tolerance to chromatic dispersion, and resistance to filter distortion. With many early patents from different organizations, optical duobinary modulation was actually invented earlier and described in a thesis by L. C. Blank. The later development of optical duobinary modulation is reviewed, including its applications for retrofitting 40-Gb/s signal into existing 10-Gb/s fiber networks.

Using digital signals as covers for steganography has attracted more and more interests in the past decades. Nowadays, patents on digital steganography mainly focus on the applications and the new steganography methods. In this paper, the U.S. patents concerning about typical digital steganography methods are reviewed based on the basic principles and their functions. Then the future challenges and potential research directions are given briefly.

In the present paper we have focussed on some different adsorbents for arsenic removal from aqueous media. Adsorbents were divided categorically in two different classes viz., synthetic adsorbents and natural adsorbents. Some of the synthetic adsorbents are found to be good for As(III) and some are good for As(V) removal. Similar results were also obtained for the natural adsorbents although removal efficiency depends on a number of factors. The efficiency of the adsorbents, merits and demerits were discussed in detail. Finally, we have discussed on some patented technologies and some potential filters.

Prognostics and health management (PHM) integrates diagnostic and prognostic technologies, provides the ability to assess the current health status of a structural system, predict its future health status for a given time period, and predict its time-to-failure for cost-effective maintenance schedule. It deals with system fault and anomaly conditions by automatic detection, classification, and prediction of critical component failures. The development of an effective PHM system for a structural system relies on both the sensing technology and the associated diagnostic and prognostic algorithms. Many sensor technologies such as strain gages, thermocouples, and accelerometers are available for use in PHM. In the meantime, a broad variety of techniques are available for damage diagnosis and prognosis of engineering structures, including but not limited to physical, statistical, intelligent, heuristic, or hybrid methods. This paper provides a state-of-the-art review on the recent development in damage diagnostics and prognostics methods applied in civil, mechanical and energy structures over the past decade. In addition, this paper introduces the basic concepts of various maintenance philosophies including corrective, preventive, and predictive maintenance. Predictive maintenance approaches such as condition based maintenance (CBM) combine the best features of corrective and preventive maintenance while avoiding the disadvantages of both. Currently it has become a popular maintenance philosophy for most high-value engineering structural systems such as airplane and gas turbine. In view of the number of recent patent applications it is reasonable to speculate that the combination of CBM and PHM will ultimately not only become the core maintenance philosophy for high-value engineering structures, but also foster further groundbreaking development and commercialization of PHM in a broad range of engineering fields.

Abnormal combustions occurred since the invention of internal combustion engines. Knock was intensively studied by researchers and engineers since this date. First patents were taken out on fuel quality (defined by octane index nowadays). After patents on sensors itself, engine settings were piloted to eliminate knock conditions in 1979-1980. Many companies followed this pathway. Latest patents on knock are reviewed. A highlight on a preventive protection (open loop control) is proposed for stationary engines fuelled natural gas, see Le Corre et al. [1]: this patent is a new concept in rupture with curative protection (closed loop control). Preventive protection is based on a gas quality sensor.

Time-Temperature Indicators (TTIs) are small devices which provide easy-to-read, visual information regarding the thermal history of perishable products. They are typically designed as small labels suitable for application onto the packaging of single product items. TTI labels are inexpensive, especially when compared to temperature electronic recorders, which are intended to monitor warehouses or means of transportation, rather than monitor single product items. Current and potential fields of application comprise food, pharmaceutical, biomedical and floral products. In the present paper the functioning principles of several TTIs are analysed with regard both to theoretical and practical aspects. There are various basic principles involved in the design of TTIs ranging from chemical reactions to physical phenomena. These principles include solid phase chemical reactions, biochemical reactions, biological systems, the transition of colour indicators in reacting phases, molecular diffusion, motion of viscous liquids, melting or glass transition of solids, gas permeation, osmosis, and nanoparticles. A selection of the most relevant patents was made according to the following criteria: the commercial success of the TTIs or their potential commercial viability, the recentness of the publications, and the originality of the fundamental principles of the inventions.

The patents annotated in this section have been selected from various patent databases. These recent patents are relevant to the articles published in this journal issue, categorized by different engineering methods, processed and techniques involved.