The boundary layer equations for plane, incompressible, and steady flow are 

$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Boundary Layer Theory

Sensor networks with battery-powered nodes can seldom simultaneously meet the design goals of lifetime, cost, sensing reliability and sensing and transmission coverage. Energy-harvesting, converting ambient energy to electrical energy, has emerged as an alternative to power sensor nodes. By exploiting recharge opportunities and tuning performance parameters based on current and expected energy levels, energy harvesting sensor nodes have the potential to address the conflicting design goals of lifetime and performance. This paper surveys various aspects of energy harvesting sensor systems- architecture, energy sources and storage technologies and examples of harvesting-based nodes and applications. The study also discusses the implications of recharge opportunities on sensor node operation and design of sensor network solutions.

Energy Harvesting Sensor Nodes: Survey and Implications

This book, written by two major figures in adaptive control, provides a wealth of material for researchers, practitioners, and students. While some researchers in adaptive control may note the absence of a particular topic, the book‘s scope represents a high-gain instrument. It can be used by designers of control systems to enhance their work through the information on many new theoretical developments, and can be used by mathematical control theory specialists to adapt their research to practical needs. The book is strongly recommended to anyone interested in adaptive control.

Adaptive Control

Energy harvesting generators are attractive as inexhaustible replacements for batteries in low-power wireless electronic devices and have received increasing research interest in recent years. Ambient motion is one of the main sources of energy for harvesting, and a wide range of motion-powered energy harvesters have been proposed or demonstrated, particularly at the microscale. This paper reviews the principles and state-of-art in motion-driven miniature energy harvesters and discusses trends, suitable applications, and possible future developments.

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Energy Harvesting From Human and Machine Motion for Wireless Electronic Devices

Wireless power technology offers the promise of cutting the last cord, allowing users to seamlessly recharge mobile devices as easily as data are transmitted through the air. Initial work on the use of magnetically coupled resonators for this purpose has shown promising results. We present new analysis that yields critical insight into the design of practical systems, including the introduction of key figures of merit that can be used to compare systems with vastly different geometries and operating conditions. A circuit model is presented along with a derivation of key system concepts, such as frequency splitting, the maximum operating distance (critical coupling), and the behavior of the system as it becomes undercoupled. This theoretical model is validated against measured data and shows an excellent average coefficient of determination of 0.9875. An adaptive frequency tuning technique is demonstrated, which compensates for efficiency variations encountered when the transmitter-to-receiver distance and/or orientation are varied. The method demonstrated in this paper allows a fixed-load receiver to be moved to nearly any position and/or orientation within the range of the transmitter and still achieve a near-constant efficiency of over 70% for a range of 0-70 cm.

/pdf/analysis-experimental-results-and-range-adaptation-of-2xhdldcpe3.pdf

Analysis, Experimental Results, and Range Adaptation of Magnetically Coupled Resonators for Wireless Power Transfer

The area of dietary assessment is becoming increasingly important as obesity rates soar, but valid measurement of the
food intake in free-living persons is extraordinarily challenging. Traditional paper-based dietary assessment methods
have limitations due to bias, user burden and cost, and therefore improved methods are needed to address important
hypotheses related to diet and health. In this paper, we will describe the progress of our mobile Diet Data Recorder
System (DDRS), where an electronic device is used for objective measurement on dietary intake in real time and at
moderate cost. The DDRS consists of (1) a mobile device that integrates a smartphone and an integrated laser package,
(2) software on the smartphone for data collection and laser control, (3) an algorithm to process acquired data for food
volume estimation, which is the largest source of error in calculating dietary intake, and (4) database and interface for
data storage and management. The estimated food volume, together with direct entries of food questionnaires and voice
recordings, could provide dietitians and nutritional epidemiologists with more complete food description and more
accurate food portion sizes. In this paper, we will describe the system design of DDRS and initial results of dietary
assessment.

Dietary intake assessment using integrated sensors and software

Model-based multi-wavelength interdigital dielectrometry parameter estimation algorithms require a good agreement between theory and measurements. Research data indicate that the agreement is high for measurement of the properties of fluid dielectrics or the sensor substrate. However, the non-ideality of the surface contact between the sensor and solid materials creates significant differences between the idealized model and experimental results. One solution to this problem is to evaluate surface contact conditions for every measurement and account for them in software. Two alternative sensor designs are compared in this paper in their ability to provide reliable measurement data that can be used by parameter estimation algorithms. Measurement of dielectric and conduction properties of both fluids and solid dielectrics are considered. It is shown that the distribution of the electric field excitation over the entire multi-wavelength sensor head, as opposed to using separate electrode wavelengths, leads to reduction of errors in parameter estimation.

Assessment of performance of fringing electric field sensor arrays

Optimization methodology for electrospray evaporative cooling chambers

Fill-front and cure progress monitoring is critical for vacuum-assisted resin transfer molding (VARTM) manufacturing processes. The experimental multi-channel system presented in this paper includes sensors, signal conditioning, data acquisition software, and signal post-processing components. The sensors are mechanically flexible and optically transparent fringing electric field electrode systems. The emphasis of the reported stage of research is on auto-calibration methods. Specifically, measurement accuracy of the system is increased by using complex sensor geometries. Effects of dielectric permittivity and temperature variations in the resin during filling and curing are also mitigated with an auto-calibration algorithm. The algorithm uses non-linear portions of the sensor to determine accurately how far the resin has progressed during filling. These sensor segments act as checkpoints and are detected by calculating first and second derivatives of the signal over time and smoothing of these curves to eliminate noise effects. Furthermore, the inclusion of additional sensors to estimate dielectric permittivity before entering the mold may provide further improvements in the monitoring algorithm. Once the resin has completely filled the mold, dielectric spectroscopy is performed to monitor cure progression using the same sensors. The transparent sensors are chosen to enable visual monitoring of the fill-front during the VARTM process.

Fill-front and cure progress monitoring for VARTM with auto-calibrating dielectric sensors

The implementation of a piezoelectric acoustic sensor for nonintrusive detection of the energization status of 3-/spl phi/ electric power cables is presented. Simultaneous excitation of a piezoelectric crystal by acoustic vibrations and electric field may occur. The Fourier spectral analysis of the sensor's output signal is used to determine the current loading status of the cable. Test results are included for both shielded and nonshielded 3-/spl phi/ cables. Also, the possible use of an optical fiber interferometer for acoustic wave detection is discussed.

Alexander Mamishev

Papers

Dietary intake assessment using integrated sensors and software

Assessment of performance of fringing electric field sensor arrays

Optimization methodology for electrospray evaporative cooling chambers

Fill-front and cure progress monitoring for VARTM with auto-calibrating dielectric sensors

Non-intrusive sensing techniques for the discrimination of energized electric cables