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Dynamic Kerr microscopy enables the analysis of structural defects in magnetic materials and their impact on the demagnetization behavior. Using new visualization techniques, it is possible to image the demagnetization process in the microstructure. It has been found that residual stresses and inclusions in soft magnets, for example, will impede magnetization. In permanent magnets, abnormally large grains, for example, will demagnetize first and then cause an accelerated demagnetization of adjacent grains.

The sustainable solvent system acetic acid + water was used to simultaneously fractionate, solvate, and clean a softwood Kraft lignin for conversion to carbon fibers. By exploiting the novel liquid...

Lignocellulose is a promising feedstock for biofuel production, while lignin poses a grand challenge on the entire process, especially enzymatic hydrolysis. In this study, different types of lignin inhibited enzymatic hydrolysis by different mechanisms. Organosolv lignin from Loblolly pine adsorbed enzyme nonproductively and reduced the available enzyme for cellulose, therefore decreasing hydrolysis rate and ultimate sugar yield. Kraft pine lignin precipitated on the surface of cellulose, preventing it from contacting with enzyme. The molecular weight influenced the inhibition effect of lignin. Lignin of lower molecular weight could bind enzyme nonproductively and when the molecular weight increased, the steric repulsion caused by lignin deposition on cellulose became more significant. The NMR analysis revealed that lignin structural features, e.g., functional groups, S/G ratio, determined the behaviors of lignin in enzymatic hydrolysis. High content of aliphatic hydroxyl groups, or low content of carboxylic groups led to high surface hydrophobicity, increasing the adsorption between lignin and enzyme. In addition, the substrate reactivity is also an important factor that affects enzymatic hydrolysis. Cellulose with higher crystallinity exhibited slower hydrolysis rate and lower conversion. When the crystallinity index increased from 0.43 to 0.72 and 0.81, the ultimate conversion decreased from 80 to 68% and 57%, respectively.

Liquid–liquid equilibrium (LLE) compositions were measured for the pseudoternary system lignin–acetic acid–water at 70 and 95 °C, conditions of interest for the Aqueous Lignin Purification using Hot Acids (ALPHA) process for the purification and fractionation of lignin. Other regions of phase behavior, including a narrow region of LLE at high acetic acid (AcOH) concentrations, as well as solid–liquid (SL) and solid–liquid–liquid (SLL) equilibria, were also identified so that the global phase behavior could be mapped out. For both temperatures, tie-lines encompassing the entire region of “ALPHA” LLE were measured, from near the liquid–liquid critical point in the AcOH-rich region to the solid–liquid–liquid (SLL) phase boundary in the water-rich region. This LLE region exhibited several interesting characteristics. Surprisingly, there was essentially no difference between the solvent compositions in the solvent-rich vs. the lignin (polymer)-rich phase, indicating that the solvent mixture is exhibiting the properties of a single liquid solvent with respect to the lignin polymer. Furthermore, a strong maximum was measured on the lignin-rich side of the binodal curve, which can occur when a solvent mixture consists of strongly associating fluids. The average molecular weight of the lignin in the lignin-rich phase was found to be an order-of-magnitude higher than in the solvent-rich phase. Acid-catalyzed lignin condensation reactions were found to occur at the highest AcOH concentrations and temperatures in the lignin-rich phase, but there was no impact on the measured phase compositions.

We investigated physical habitat conditions associated with the spawning sites of Chinook Salmon Oncorhynchus tshawytscha and the interannual consistency of spawning distribution across multiple spatial scales using a combination of spatially continuous and discrete sampling methods. We conducted a census of aquatic habitat in 76 km of the upper main-stem Yakima River in Washington and evaluated spawning site distribution using redd survey data from 2004 to 2008. Interannual reoccupation of spawning areas was high, ranging from an average Pearson’s correlation of 0.62 to 0.98 in channel subunits and 10-km reaches, respectively. Annual variance in the interannual correlation of spawning distribution was highest in channel units and subunits, but it was low at reach scales. In 13 of 15 models developed for individual years (2004–2008) and reach lengths (800 m, 3 km, 6 km), stream power and depth were the primary predictors of redd abundance. Multiple channels and overhead cover were patchy but were ...

Lignin depolymerization to aromatic monomers with high yields and selectivity is essential for the economic feasibility of many lignin-valorization strategies within integrated biorefining processes. Importantly, the quality and properties of the lignin source play an essential role in impacting the conversion chemistry, yet this relationship between lignin properties and lignin susceptibility to depolymerization is not well established. In this study, we quantitatively demonstrate how the detrimental effect of a pretreatment process on the properties of lignins, particularly β-O-4 content, limit high yields of aromatic monomers using three lignin depolymerization approaches: thioacidolysis, hydrogenolysis, and oxidation. Through pH-based fractionation of alkali-solubilized lignin from hybrid poplar, this study demonstrates that the properties of lignin, namely β-O-4 linkages, phenolic hydroxyl groups, molecular weight, and S/G ratios exhibit strong correlations with each other even after pretreatment. Furthermore, the differences in these properties lead to discernible trends in aromatic monomer yields using the three depolymerization techniques. Based on the interdependency of alkali lignin properties and its susceptibility to depolymerization, a model for the prediction of monomer yields was developed and validated for depolymerization by quantitative thioacidolysis. These results highlight the importance of the lignin properties for their suitability for an ether-cleaving depolymerization process, since the theoretical monomer yields grows as a second order function of the β-O-4 content. Therefore, this research encourages and provides a reference tool for future studies to identify new methods for lignin-first biomass pretreatment and lignin valorization that emphasize preservation of lignin qualities, apart from focusing on optimization of reaction conditions and catalyst selection.

Hot acetic acid–water mixtures can be used to purify and fractionate alkali (kraft) and organosolv lignins via the Aqueous Lignin Purification with Hot Acids (ALPHA) process. However, condensation polymerization reactions can occur in the solvated, lignin-rich liquid fraction at the elevated temperatures (e.g., 60–100 °C) of operation, significantly increasing the lignin molecular weight. Thus, conversion of ALPHA to continuous-flow operation was investigated in order to determine the effect of reduced residence times on both the above reactions and on the extraction of metals from the solvated lignin to the solvent phase. All four lignins investigated could be converted to a homogeneous lignin–water slurry at ambient temperatures, facilitating continuous operation. When a static mixer is used for the mixing and equilibration device, reducing residence times to 20–30 s, condensation polymerization reactions are essentially eliminated. For example, the molecular weight of the lignin fraction remained uncha...

Lignin is unique among renewable biopolymers in having significant aromatic character, making it potentially attractive for a wide range of uses from coatings to carbon fibers. Recent research has shown that hot acetic acid (AcOH)–water mixtures can be used to recover “ultraclean” lignins of controlled molecular weight from Kraft lignins. A key feature of this discovery is the existence of a region of liquid–liquid equilibrium (LLE), with one phase being rich in the purified lignin and the other rich in solvent. Although visual methods can be used to determine the temperature at which solid lignin melts in the presence of AcOH–water mixtures to form LLE, the phase transition can be seen only at lower AcOH concentrations due to solvent opacity. Thus, an electrochemical impedance spectroscopy (EIS) technique was developed for measuring the phase-transition temperature of a softwood Kraft lignin in AcOH–water mixtures. In electrochemical cells, the resistance to double-layer charging (i.e., polarization resistance Rp) is related to the concentration and mobility of free ions in the electrolyte, both of which are affected by the phases present. When the lignin–AcOH–water mixture was heated through the phase transition, RP was found to be a strong function of temperature, with the maximum in RP corresponding to the transition temperature obtained from visual observation. As the system is heated, acetate ions associate with the solid lignin, forming a liquefied, lignin-rich phase. This association increases the overall impedance of the system, as mobile acetate ions are stripped from the solvent phase and thus are no longer available to adsorb on the polarizing electrode surfaces. The maximum in RP occurs once the new lignin-rich phase has completely formed, and no further association of the lignin polymer with AcOH is possible. Except at sub-ambient temperatures, the phase-transition temperature was a strong function of solvent composition, increasing linearly from 18 °C at 70/30 AcOH/water to 97 °C at 10/90 wt% AcOH/water.

The miniaturization of acoustic transmitters may allow greater flexibility in terms of the size and species of fish available to tag. New downsized injectable acoustic tags similar in shape to passive integrated transponder tags can be rapidly injected rather than surgically implanted through a sutured incision. Before wide-scale field use of these injectable transmitters, standard protocols to ensure the most effective and least damaging methods of implantation must be developed. Three implantation methods were tested in various sizes of juvenile Chinook salmon (Oncorhynchus tschawytscha). Methods included a needle bevel-down injection, a needle bevel-up injection with a 90° rotation, and tag implantation through an unsutured incision. Tagged fish were compared to untagged control groups. Weight and wound area were measured at tagging and every week for 3 weeks; holding tanks were checked daily for mortalities and tag losses. No significant differences among treatments were found in tag loss, or survival, but wound area was significantly reduced among fish tagged via an incision and growth was slightly reduced in bevel down fish. Although there were no significant differences, the bevel-up injection trended toward having the worst results in terms of tag loss and wound area and had high mortality. Implantation through an incision resulted in the lowest tag loss but the highest mortality. Fish from the bevel-down treatment group had the least mortality and smaller wound areas than the bevel-up treatment group but also showed reduced growth. Cumulatively, the data suggest that the unsutured incision and bevel-down injection methods were the most effective; the drawbacks of both methods are described in detail.

Liquid–liquid equilibrium (LLE) tie-line compositions were measured for the binary system iodine–water and the ternary system hydrogen iodide–iodine–water (HI–I2–H2O) at 199.1 and 252.2 °C, at pressures of 60 bar, conditions of interest for the reactive distillation column of the Sulfur–Iodine Cycle. To keep the HI decomposition reaction negligible, a continuous-flow apparatus was used to minimize residence times at the elevated temperatures. Sixteen equilibrium tie lines were measured, using overall feed compositions ranging from 0.0 to 3.3 mol % HI, and the plait-point composition for 199.1 °C was estimated. Sample compositions for the lighter, water-rich phase and the heavier, I2-rich phase were both determined via titration of HI and I2, with water being obtained by difference. The phase behavior indicates that the selectivity of HI for the aqueous phase can be large, ranging from 10 to 100+ for tie lines removed from the critical region.

Spawning site selection by female salmon is based on complex and poorly understood tradeoffs between the homing instinct and the availability of appropriate habitat for successful reproduction. Previous studies have shown that hatchery-origin Chinook salmon (Oncorhynchus tshawytscha) released from different acclimation sites return with varying degrees of fidelity to these areas. To investigate the possibility that homing fidelity is associated with aquatic habitat conditions, we quantified physical habitat throughout 165 km in the upper Yakima River basin (Washington, USA) and mapped redd and carcass locations from 2004 to 2008. Principal components analysis identified differences in substrate, cover, stream width, and gradient among reaches surrounding acclimation sites, and canonical correspondence analysis revealed that these differences in habitat characteristics were associated with spatial patterns of spawning (p

Individuals with autism spectrum disorder (ASD) have distinctive needs with respect to sexual development and education. This pilot study evaluates the effectiveness of a parent-implemented Social Story intervention with an embedded visual task analysis to teach menstrual care skills to three young girls with ASD. Skill generalization was evaluated using two different types of pads and a simulated condition (i.e., a pad with red syrup). Social validity of target behaviors, intervention procedures and intervention effects were evaluated. Additionally, qualitative changes in participant behaviors were measured via phone interviews with the participants’ mothers (Bruess and Greenberg 1994) 1 year later. Results indicate that participants were more knowledgeable about reproductive development and were able to independently care for their menses regardless of pad type (wings vs. no-wings) and condition (clean vs. dirty). Parents reported high satisfaction with the intervention procedures and outcomes. Implications of the study and future research are discussed.

Scanning proximity probes are uniquely powerful tools for analysis, manipulation, and bottom-up synthesis. A massively parallel cantilever-probe platform is demonstrated. 128 self-sensing and self-actuated proximal probes are discussed. Readout based on piezoresistive sensors and bending control based on bimorph dc/ac actuations are described in detail.

Although a number of treatment methods can be used to separate cellulose and lignin components from biomass, aqueous alkaline treatment methods are dominant. Typically, the cellulose is precipitated from solution, and the lignin ends up in the highly alkaline liquor by-product stream. Today the vast majority of this lignin is burned in situ as a fuel; however, it potentially has far more value as a renewable biopolymer. Here, two new technologies are presented for recovering lignin from alkaline liquor streams generated either from a pulp-and-paper mill or a lignocellulosic biofuels refinery. With SLRPTM technology, the lignin precipitation step is carried out at above-ambient conditions such that a liquid (and not a solid) lignin phase is formed. Thus, the SLRP process for producing low-ash (1–2 %) lignin is continuous, not batch. Furthermore, the “liquid-lignin” phase can be readily fractionated by pH into fractions having different bulk and molecular properties. The ALPHA process was developed with the express purpose of taking low-ash lignins produced from alkaline-liquor by-product streams to the “ultrapure” state. The technology uses adjustable mixtures of biorenewable acetic acid and water to create a unique liquid–liquid solvent system that can be used to simultaneously fractionate, purify, and solvate lignins. Metals contents in ALPHA lignins well below 100 ppm are readily achieved in fractions of both low and high molecular weight.

A thermally actuated micro gripper with two integrated micro actuators for open/close action was designed and fabricated from single crystal silicon. A total gripping range of [email protected] was observed for driving voltages below 5V. The actuation efficiency is (-0.18+/-0.04)@mm/V^2 for the close-action, and (0.57+/-0.01)@mm/V^2 for the open-action actuator.

By operating in a region of liquid–liquid equilibrium, hot acetic acid–water mixtures can be used to simultaneously clean, fractionate, and solvate Kraft black-liquor lignins. Lignin-rich liquid phases of controlled molecular weight with key metals contents reduced to

Kraft lignin was fractionated by molecular weight (MW), using CO2-expanded solutions of acetic acid/water in a 90/10 wt/wt ratio. In particular, as CO2 pressures were increased from 7 bar to 48 bar, expanding the liquid-solvent phase and reducing its dielectric strength, lignin fractions decreasing in MW from 15 000 to 1250, with polydispersity index (PDI) values decreasing from 3.7 to 1.6, were obtained. The recovered lignin fractions were similar, in terms of chemical functionality. With the use of gas-expanded liquids (GXL), only one solvent composition is required, and recovery and reuse of the biorenewable CO2 + acetic acid–water solution is facilitated through pressure release and recompression. The process was demonstrated for the recovery of seven lignin fractions to demonstrate its versatility and effectiveness, but simpler operation with recovery of just a low MW lignin fraction and a high MW lignin fraction is more consistent with anticipated applications.

Wireless sensing using passive sensors based on surface acoustic wave (SAW) technology is necessary for many applications. In this paper a new sensor design that uses the differential frequency output from two SAW resonators (SAWR) for temperature and pressure measurement is presented. The sensor, which consists of two SAWRs on the same substrate with different SAW propagation directions, relies on the variations of the SAW propagation velocity to measure environmental quantities such as pressure or temperature. The aim of this approach is to suppress the disturbing influences of the RF link (radio channel) between the interrogation unit and the passive sensor device. In this case, the output signal is a frequency difference and does not depend on changes in the radio channel during the transmission of the sensor signal.

This is the postprint version of the article. The printed version of the article can be found here: http://www.springerlink.com/content/jl0122219v283124/ Research showing that salmon carcasses support the productivity and biodiversity of aquatic and riparian ecosystems has been conducted over a variety of spatial and temporal scales. In some studies, carcasses were manipulated in a single pulse or loading rate or manipulations occurred during summer and early fall, rather than simulating the natural dynamic of an extended spawning period, a gradient of loading rates, or testing carcass effects in late fall-early winter when some salmon stocks in the US Pacific Northwest spawn. To address these discrepancies, we manipulated salmon carcass biomass in 16 experimental channels located in the sunlit floodplain of the Cedar River, WA, USA between mid-September and mid-December, 2006. Total carcass loads ranged from 0–4.0 kg/m2 (0, 0.001, 0.01, 0.1, 0.5, 1.0, 2.0 and 4.0 kg/m2, n = 2 per treatment) and were added to mimic the temporal dynamic of an extended spawning period. We found little evidence that carcasses influenced primary producer biomass or fish growth; however, nutrients and some primary consumer populations increased with loading rate. These effects varied through time, however. We hypothesize that the variable effects of carcasses were a result of ambient abiotic condition, such as light, temperature and disturbance that constrained trophic response. There was some evidence to suggest peak responses for primary producers and consumers occurred at a loading rate of *1.0–2.0 kg/m2, which was similar to other experimental studies conducted during summer.

Following recommendations made in Homeland Security Presidential Directive 7, which established a national policy for the identification and increased protection of critical infrastructure and key resources (CIKR) by Federal departments and agencies, the U.S. Department of Homeland Security (DHS) in 2006 developed the Enhanced Critical Infrastructure Protection (ECIP) program. The ECIP program aimed to provide a closer partnership with state, regional, territorial, local, and tribal authorities in fulfilling the national objective to improve CIKR protection. The program was specifically designed to identify protective measures currently in place in CIKR and to inform facility owners/operators of the benefits of new protective measures. The ECIP program also sought to enhance existing relationships between DHS and owners/operators of CIKR and to build relationships where none existed (DHS 2008; DHS 2009). In 2009, DHS and its protective security advisors (PSAs) began assessing CIKR assets using the ECIP program and ultimately produced individual protective measure and vulnerability values through the protective measure and vulnerability indices (PMI/VI). The PMI/VI assess the protective measures posture of individual facilities at their 'weakest link,' allowing for a detailed analysis of the most vulnerable aspects of the facilities (Schneier 2003), while maintaining the ability to produce an overall protective measuresmore » picture. The PMI has six main components (physical security, security management, security force, information sharing, protective measures assessments, and dependencies) and focuses on actions taken by a facility to prevent or deter the occurrence of an incident (Argonne National Laboratory 2009). As CIKR continue to be assessed using the PMI/VI and owners/operators better understand how they can prevent or deter incidents, academic research, practitioner emphasis, and public policy formation have increasingly focused on resilience as a necessary component of the risk management framework and infrastructure protection. This shift in focus toward resilience complements the analysis of protective measures by taking into account the three other phases of risk management: mitigation, response, and recovery (Figure 1). Thus, the addition of a robust resilience index (RI) to the established PMI/VI provides vital information to owners/operators throughout the risk management process. Combining a pre-incident focus with a better understanding of resilience, as well as potential consequences from damaged CIKR, allows owners/operators to better understand different ways to decrease risk by (1) increasing physical security measures to prevent an incident, (2) supplementing redundancy to mitigate the effects of an incident, and (3) enhancing emergency action and business continuity planning to increase the effectiveness of recovery procedures. Information provided by the RI methodology is also used by facility owners/operators to better understand how their facilities compare to similar sector/subsector sites and to help them make risk-based decisions. This report provides an overview of the RI methodology developed to estimate resilience and provide resilience comparisons for sectors and subsectors. The information will be used to (1) assist DHS in analyzing existing response and recovery methods and programs at facilities and (2) identify potential ways to increase resilience. The RI methodology is based on principles of Appreciative Inquiry, which is 'the coevolutionary search for the best in people, their organizations, and the relevant world around them' (Cooperrider et al. 2005). Appreciative Inquiry identifies the best of 'what is' and helps to envision 'what might be.' The ECIP program and the RI represent a new model (using Appreciative Inquiry principles) for information sharing between government and industry (Fisher and Petit 2010). A 'dashboard' display, which provides an interactive tool - rather than a static report, presents the results of the RI in a convenient format. Additional resilience measures can be modeled to illustrate how such actions would impact the asset's RI value.« less

The US Department of Homeland Security (DHS) has directed its Protective Security Advisors (PSAs) to form partnerships with the owners and operators of assets most essential to the Nation's well being - a subclass of critical infrastructure and key resources (CIKR) - and to conduct site visits for these and other high-risk assets as part of the Enhanced Critical Infrastructure Protection (ECIP) Program. During each such visit, the PSA documents information about the facility's current CIKR protection posture and overall security awareness. The primary goals for ECIP site visits (DHS 2009) are to: (1) inform facility owners and operators of the importance of their facilities as an identified high-priority CIKR and the need to be vigilant in light of the ever-present threat of terrorism; (2) identify protective measures currently in place at these facilities, provide comparisons of CIKR protection postures across like assets, and track the implementation of new protective measures; and (3) enhance existing relationships among facility owners and operators; DHS; and various Federal, State, local tribal, and territorial partners. PSAs conduct ECIP visits to assess overall site security; educate facility owners and operators about security; help owners and operators identify gaps and potential improvements; and promote communication andmore » information sharing among facility owners and operators, DHS, State governments, and other security partners. Information collected during ECIP visits is used to develop metrics; conduct sector-by-sector and cross-sector vulnerability comparisons; identify security gaps and trends across CIKR sectors and subsectors; establish sector baseline security survey results; and track progress toward improving CIKR security through activities, programs, outreach, and training (Snyder 2009). The data being collected are used in a framework consistent with the National Infrastructure Protection Plan (NIPP) risk criteria (DHS 2009). The NIPP framework incorporates consequence, threat, and vulnerability components and addresses all hazards. The analysis of the vulnerability data needs to be reproducible, support risk analysis, and go beyond protection. It also needs to address important security/vulnerability topics, such as physical security, cyber security, systems analysis, and dependencies and interdependencies. This report provides an overview of the approach being developed to estimate vulnerability and provide vulnerability comparisons for sectors and subsectors. the information will be used to assist DHS in analyzing existing protective measures and vulnerability at facilities, to identify potential ways to reduce vulnerabilities, and to assist in preparing sector risk estimates. The owner/operator receives an analysis of the data collected for a specific asset, showing a comparison between the facility's protection posture/vulnerability index and those of DHS sector/subsector sites visited. This comparison gives the owner/operator an indication of the asset's security strengths and weaknesses that may be contributing factors to its vulnerability and protection posture. The information provided to the owner/operator shows how the asset compares to other similar assets within the asset's sector or subsector. A 'dashboard' display is used to illustrate the results in a convenient format. The dashboard allows the owner/operator to analyze the implementation of additional protective measures and to illustrate how such actions would impact the asset's Protective Measures Index (PMI) or Vulnerability Index (VI).« less

SAW resonators are particularly suitable for passive wireless sensing because of the high Q factor (storage of rf energy) and the possibility to change their resonance be- haviour influenced by an external measurand (frequency pulling). The sensor is build not only by a physical af- fecting of the acoustic wave but also by an electrical interaction outside the resonator (e.g. capacitive or inductive). The sensor signal is determined by the ex- ternal circuit elements and manifests in a fre- quency and amplitude shift. The pulling frequency and the optimum pulling span, also the transmitted power are estimated by the external reactive circuit ele- ments, as well as by the SAW-Resonator characteristic. To obtain the maximum power transmis- sion, a matching between the sensor element and the antenna for wireless interrogation is necessary; simultaneously, one element of the matching network is the sensing element that pulls the frequency. For well-designed sensors, the parameters of equivalent circuitry of the resonator have to be estimated with a high accuracy, in order to simulate the resonator pulling in combination with different matching networks. Thus, from all the L-, Pi- and T-sections, the eligible con- figuration were selected and tested in order to ensure the maximum power transmission in a wide pulling range. This paper presents simulation and ex- perimental results for designing proper sensor systems.

The application of surface acoustic wave (SAW) resonators as sensor elements for different physical parameters such as temperature, pressure, and force has been well-known for several years. The energy storage in the SAW and the direct conversion from physical parameter to a parameter of the wave, such as frequency or phase, enables the construction of a passive sensor that can be interrogated wireless. This paper presents a temperature-measurement system based on passive wireless SAW sensors. The principle of SAW sensors and SAW sensor interrogation is discussed briefly. A new measurement device developed for analyzing the sensor signals is introduced. Compared to former interrogation units that detect resonance frequency of the SAW resonator by comparing amplitudes of sensor response signals related to different stimulating frequencies, the new equipment is able to measure the resonance frequency directly by calculating a Fourier transformation of the resonator response signal. Measurement results of an experimental setup and field tests are presented and discussed.

The usage of SAW resonators as remote sensors is well known. Double resonator sensors for reducing disturbing influences from the radio channel as well as the separation of the sensor element from the SAW device into the matching network are already presented in M. Binhack et al. (2000). Here the change of the difference frequency is the sensor signal. Corrected matching was used to integrate the sensor function in the matching network as stated in S. Klett et al. (2002), e.g. as a capacitive sensor. For passive wireless sensors it is very important to optimize the sensitivity and the resolution while keeping the energy conditions sufficient to be able to interrogate at longer distances. The system design for e.g. strain gauge sensors without sensitivity to the temperature demands to special properties of the used resonators. This paper shows a systematic calculation of the resonator behavior by using the PEC (parameters of equivalent circuit). The influence of the matching conditions and the connected SAW devices to different frequency detuning are calculated and compared to specified pairs of resonators. To extend the difference frequency shift by the sensor variation, resonators with obvious unequal Q factor have to be used. Furthermore a certain derivation of the single resonator impedance results in different frequency dependencies from the detuning capacitor. This can be influenced during the design and fabrication process of the SAW devices. Typical values like the Q factor, the serial and parallel resonance frequency or the impedance of the SAW devices were taken to build the model of the double SAW resonator sensor. Finally the model is used to draw conclusions to the design parameters like reflection coefficient or aperture of the resonators to optimize the sensor behavior.

This paper discusses SAW resonators. The SAW device consists of a piezoelectric substrate with a metalization. It is shown that the sytems langasite-Pt and gallium orthophosphate-Pt are able to fulfill the demands for a high temperature operation. An AFM scan of metalization is also available.

SAW resonators are particularly suitable for passive wireless sensing because of the high Q factor. The returned sensor signal consists of a frequency shift and a change in the amplitude. To ensure a good performance, such passive systems have to be carefully designed for energy efficiency and for the demands of the interrogation regime. For well designed sensors, the parameters of equivalent circuitry (PEC) of the resonator have to be estimated, in order to simulate the resonator in combination with the matching network. Hereby, the matching network does not only match the resonator - it transforms the whole resonance behavior and influences it. So a sensor is constructed by the implementation of a sensing element (e.g. variable capacitor) into the matching network. Based on measured data of different resonator types, the PEC have been precisely calculated by an improved method. The PEC model is extended by a matching network to simulate the interaction between the two parts, which leads to a modified resonance behavior. Consequently, different matching circuits have been calculated and measured for the applicability of pulling the resonance frequency inside a reasonable region of mismatching. For practical purposes, an approximation of the sensing capacity and the pulling sensitivity is possible. This paper discusses the simulations, which have been verified by experiments.

Identification devices (ID-tags) for remote telemetry systems in the European ISM standards require the use of narrow-band solutions. SAW ID-tags are characterized by particularly good coding and correlation capabilities which is used in many filter applications. To solve the narrow-band problem of ISM-bands two principles for passive SAW ID-Tags were introduced, the Multiple Apodized Self-Correlating Delay Line (MASCoT) and the "On-Chip-Correlation" (OCC) device. The advantage of the devices is an "impulse-free" interrogation so that the used bandwidth does not extend the allowed bandwidth and the European ISM standard can be fulfilled. The design, simulation and experimental results were introduced and discussed.

SAW devices are characterized by particularly good coding and correlation capabilities which are used in matched filter application. If the signal code given to such a device corresponds to a code implemented in a correlation device there will be generated a typical correlation peak at its output. In the case of an "on-chip-correlation" (OCC) device the correlation function is used to create a peak in form of a surface acoustic wave on the chip. The first test device consists of two different PSK coded SAW structures which are connected to the antenna over a common signal bus. When the device is interrogated by a coded RF signal the input transducer generates a wave pulse (OCC peak). Passing the second PSK transducer the impulse will generate a PSK signal corresponding to the structure of the second transducer. The coded signal will be transferred back to the interrogation unit and thus identify the measured object. It is ensured that the interaction between different transducer codes does not falsify the output signal. The advantage of the new device is an "impulse-free" interrogation so that the used bandwidth does not oversize the allowed 1.74 MHz bandwidth and the European ISM standard can be fulfilled. The design, simulation and experimental results of the 80 MHz and the 433.92 MHz device setup were introduced and discussed.

A special SAW device design, derived from conventional tapped delay lines and optimized for wireless interrogation as a two-terminal ID-tag and sensor, is presented. The working principle is based on superposition of the correlation signals of multiple apodized transducer pairs that are connected in parallel. In the device, every transducer (tap) works as both, receiver and transmitter. Design rules for calculating the apodization of multiple transducers for a given PSK-code sequence are discussed under consideration of second order effects. Optimization criteria for low-loss design of diffraction-compensated devices are addressed. Measurement results for designs with and without diffraction compensation are shown and device characteristics are derived from the results. The measured ID-tag samples were fabricated on a 128/spl deg/-YX-LiNbO/sub 3/ substrate to operate at 433.92 MHz.

The basic idea of this sensor is to integrate the capacitive or inductive sensing element into the matching network of the Antenna-SAW-Resonator-System. By changing the matching network the resonance frequency is shifted over a certain range. Two SAW-Resonators are used in order to reduce several external disturbing influences of the radio channel. The change of the difference frequency is the output signal of the sensor system. The SAW-Resonator well protected by a packaging works as transmitter and not as sensing element. Concerning the separation of transmitter and sensing element both of them can be optimized separately. Therefore many physical or chemical properties like pressure, acceleration, strain, pollution and others can be measured with this wireless passive sensor system. Solutions for special applications at extreme environmental conditions like rotation, high temperature or similar can be realized with this passive wireless sensor system.

This paper presents the use of surface acoustic wave resonators (SAWRs) in passive remote identification and sensor system in the European 433.92 MHz ISM-band. The identification device consists of a SAWRs parallel circuitry and is connected via matching network to the Tx/Rx antenna. The narrowband interrogation was the main criteria for the device development. An integrated sensor function was added by sensitive SAWR. Depending on application a direct peak frequency change or a differential frequency method are feasible. Theoretical and experimental results of the SAW resonator identification tag (RESTAG) with 5 and 12 bits respectively are presented and discussed. The device was developed and optimized for the identification and temperature measurement.

The infrared spectra of [Pd(dien)I]I, [Pd(dien)Br]Br, and [Pd(dien)Cl]Cl have been observed and assignments made in the region 200–4000 cm −1 . The investigation of these spectra is intended to provide the background and basis for the study of the spectra of (dien-H) complexes [where (dien-H) represents a diethylenetriamine ligand from which one proton has been removed] in regard to the character of the bond between the metal ion and the ligand nitrogen atom from which the proton is removed. The assignment of several bands was facilitated by the infrared spectrum (200–4000 cm −1 ) of the new complex [Pd(tmdien)I]I (tmdien = 1,4,7-trimethyldiethylenetriamine).