Stability

This paper describes the analysis of L-band radiometric measurement data gathered with the synthetic aperture radiometer HUT-2D during several ground-based and airborne measurement campaigns. The radiometric data are analyzed from the instrument's performance point of view, aiming to verify the theoretical performance of an instrument of this kind and to assess the performance of the HUT-2D radiometer system in particular. The data sets considered for the study consist of measurements of well-known natural targets, such as cosmic background radiation, and measurements of pure water scenes, the brightness temperature of which is possible to model based on in situ measurements. We define four figures of merit, which are applicable for synthetic aperture radiometers. These are radiometric resolution, image bias, pixel-to-pixel random error, and temporal stability. Then, we use the selected data sets to assess these in the case of HUT-2D. The experimental results are discussed and compared to the theoretical values, where applicable. Also, we discuss possibilities to improve the presented performance. The main results of this paper are the consolidated performance parameters of the HUT-2D instrument. We study and discuss the properties of the error components related to the technology in a general level, and study the scalability of the errors as a function of the measured targets. In particular, the stability of the direction-dependent error component is pointed out, and a mitigation guideline is proposed.

This paper deals with the solution of the stress, displacement, and pore pressure field induced by the drilling and~or the pressurization of a vertical borehole. The rock, which is permeated by fluid, is assumed to behave as a poroelastic material with compressible constituents, following the Biot theory. The analytical solution is derived in the Laplace transform space, and is transformed to the time domain using an approximate numerical inversion technique. The solution reveals a full range of coupled poroelastic effects which provide potential mechanisms for delayed borehole instability and shear fracture initiation inside the rock.

Many food emulsions are frozen to provide long-term stability to the product or as a necessary part of the food itself (e.g., ice cream), but very often the thawed emulsion is significantly destabilized and sometimes completely broken down into an oily and an aqueous phase. The phase behaviour of the frozen emulsion and hence the potential stresses can be calculated from the composition of the aqueous phase. For example, a 20% o/w emulsion prepared with 10% sucrose in the aqueous phase when frozen to À20 1C about 85% of the aqueous phase has frozen to ice leaving the unfrozen phase concentrated to about 62% with respect to droplets and 67% with respect to sucrose. The high-volume fraction and expanding ice press the droplets together and the high sugar (and other solute) concentration can affect the interdroplet forces. A combination of these effects can lead to the membrane separating the droplets rupturing and is responsible for the coalescence seen on thawing. The published studies on freeze-thaw stability of emulsions are reviewed within the framework provided by the phase diagram calculations. r

Επιβλέπουσα Καθηγήτρια: ΝΑΣΚΟΥ-ΠΕΡΡΑΚΗ Παρασκευή Τηλ.: 2310 891499 Email: perraki@uom.gr Β΄ Μέλος Εξεταστικής Επιτροπής: ΜΠΕΛΛΟΥ ΦωτεινήΤηλ.: 2310 891479 Email: fbellou@uom.gr
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<a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/gr/"><img alt="Άδεια Creative Commons" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/gr/88x31.png" /></a><br />Αυτό το εργασία χορηγείται με άδεια <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/gr/">Creative Commons Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα </a>."

Λέξεις Κλειδιά:

ασφάλεια, ειρήνη, τάξη, σταθερότητα, ισχύς, συνεργασία, συγκρούσεις, περιπτωσιολογικές μελέτες, φάσμα, εκκρεμές, πλαίσιο, πρίσμα, νομιμότητα, νομιμοποίηση, δόγμα, στρατηγική αντίληψη, σύστημα, ηγεμονία, αρχή, επέμβαση, ευθύνη, προστασία"

Συμπέρανα ότι, το ΝΑΤΟ μετεξελίσσεται σε οργανισμό που έχει τα χαρακτηριστικά ενός διεθνούς περιφερειακού οργανισμού, σε παγκόσμια όμως διάσταση, όπου με βάση το δόγμα "Ευθύνη Προστασίας" (Responsibility to Protect), αναλαμβάνει ρόλο χωροφύλακα, που επιδιώκει τη διασφάλιση της διεθνούς ασφάλειας και του εσωτερικού τομέα ασφαλείας, σε οριακές συγκρούσεις ανά την υφήλιο, πχ Βοσνία, Κόσσοβο, Λιβύη και προσεχώς Συρία."

Nowadays there is an increase in the request for compounded medicines or extemporaneous formulations, mainly for situations that are not covered by the Pharmaceutical Industry. Compounded medicines must follow quality parameters that are required by law and are included in different pharmacopoeias. This review aims to present the main factors that condition compounded formulations stability and hence determine expiry dates.

The B cell antigen receptor (BCR) comprises the membrane-bound immunoglobulin (mIg) molecule and the Ig-a/Ig-b heterodimer. By comparing the stability of the IgD-BCR and IgM-BCR in dierent detergent lysates, we ®nd that the IgD-BCR is more stable than the IgM-BCR. Analysis of chimeric mIgD molecules suggests that the dm transmembrane region is responsible for the more stable association of mIgD with the Ig-a/Ig-b heterodimer. Further, the dierential glycosylation of Iga molecules, in the two dierent BCR complexes, is determined solely by the ectodomains of the mIg molecules. The implications of these ®ndings for the intracellular transport and the signalling capacity of the BCRs are discussed.

This paper describes new matrix transformations suited to the eficient calculation of critical eigenvalues of large scale power system dpamic models. The key advantage of these methods is their ability to converge to the critical eigenvalues (unstable or low damped) of the system almost independently of the given initial estimate. Matrix transforms such as inverse iteration and S-matrix can be thought as special cases of the described method. These transforms can also be used to inhibit convergence to a known eigenvalue, yielding better overall eficiency when finding several eigenvalues.

Bistable structures, such as buckled beams or plates, are characterized by a two-well potential. Their nonlinear properties are currently exploited in actuators design (e.g. MEMS micropumps, switches, memory cells) to produce relatively high displacements and forces with low actuation energies. We investigate the use of distributed multiparameter actuation to control the buckling and postbuckling behaviour of a three-layer piezoelectric beam pinned at either end. A two-parameter bending actuation controls the transversal motion, whilst an axial actuation and a beam end-shortening modulate the tangent bending stiffness. The postbuckling behaviour is studied by reducing to a 2 dof system a nonlinear extensible elastica model. When the bending actuation is spatially symmetric, the postbuckling phenomena are analogue to those obtained for a transversal midspan force, being characterized by a snapthrough instability. The use of a two-parameter actuation opens new transition scenarios, where it is possible to get true quasi-static transitions between the two specular equilibria of the buckled beam, without any instability phenomenon. The efficiencies of these different transition paths are discussed in terms of energetic requirements and stability properties. A numerical example shows the technical feasibility of the proposed actuation technique.

On-line tool wear monitoring in metal-cutting operations is essential for an on-line process optimization. In this paper, tool flank wear is estimated on-line by utilizing a nonlinear observer with the feedback of cutting force measurements. Based on a previously developed cutting process model for turning, a nonlinear observer is designed such that the estimated flank wear converges to the actual flank wear development in the presence of poor initial estimates. The stability analysis for the resulting observer error dynamic system is carried out using a physical limitation of the actual flank wear development and the Total Stability Theorem. The experimental results show that the proposed nonlinear observer estimates the flank wear quite well not only in the presence of poor initial estimates but also in the presence of unexpected fluctuations in the cutting force measurements. However, the method has drawbacks resulting from difficulties in obtaining accurate model parameters. An adaptive version of the presented nonlinear observer, periodically calibrated by off-line direct tool wear measurements using computer vision, is considered to be a promising strategy for industrial implementation.

The study of the dynamics of a simple batch distillation usually assumes the equilibrium between the liquid and vapour phases. In contrast to that approach, this work considers the analysis of the dynamic behaviour of a nonequilibrium simple batch distillation. A simple batch distillation device is similar to an evapouration unit because no reflux is employed. A mathematical model and their singular points are analysed through the usual technique of linearization followed by the eigenvalues analysis. The stability nature of those points is presented for ideal solutions. Phase plane plots are made to show the occurrence of some unexpected behaviours such as 'dynamic azeotropic points' and 'inversion of the distillation order'. The dependence of these phenomena on the vapour withdrawal flowrate is established for simple batch distillation. #

Magnetorheological fluids (MRFs) are typically thought of as Bingham-plastic (BP) fluids characterized by a yield stress. Partial substitution of micrometer-scale Fe particles with nanometer-scale Fe particles leads to bidisperse MRFs. This partial substitution mitigates particle sedimentation, but can reduce yield stress for high nanoparticle concentrations. We examine tradeoffs between increasing suspension stability versus decreasing in yield stress as nanoparticles are substituted for microparticles. Four groups of fluids with total Fe concentration of 50, 60, 70, and 80 wt% were considered. A sedimentation measuring device quantified sedimentation velocity of MRFs in a gravitational field. This sensor relates the rate of change of inductance relative to settling rate as Fe wt% decreases because of sedimentation. MRF flow curves were measured using a parallel disk rheometer and yield stress was identified using the BP flow model.

A globally convergent adaptive control scheme for robot motion control with the following features is proposed. First, the adaptation law possesses enhanced robustness with respect to noisy velocity measurements. Second, the controller does not require the inclusion of high gain loops that may excite the unmodeled dynamics and amplify the noise level. Third, we derive for the unknown parameter design a relationship between compensator gains and closed-loop convergence rates that is independent of the robot task. A simulation example of a two-DOF manipulator features some aspects of the control scheme.

We address scaling of the "dynamic systems" approach for robot planning to multi-agent cooperation. To accommodate this extension it is necessary to carefully consider how individual behaviors contribute to the vector field. To avoid spun"ous minima and related pro biems a competition dynamics is introduced and its stability is analyzed. A system of two cooperating agents is designed, and examples are presented to illustrate the utility of this approach.

The feasibility of utilizing infrared spectroscopy for the prediction of haze formation in white wines resulting from heat and colloidal stability tests was investigated. One-hundred eleven white wines, representing multiple regions and varieties from the 2008 California vintage, were collected and analyzed. The near and mid-infrared spectra were measured and heat and colloidal (ethanol addition) stability tests were performed on the same wines. Partial-least squares regression analysis was then used to construct models predictive of the resulting nepholometric turbidity to the acquired spectra. Preliminary models obtained following application of spectral pretreatments today considered as ''classical'' (e.g., derivatives, standard normal variate, vector normalization, constant offset elimination) lacked robustness; two alternative algorithms designed to remove spectral information unrelated to the turbidity were then employed (orthogonal signal correction; direct orthogonal signal correction). While OSC pretreatment did not result in more robust models, DOSC considerably enhanced the goodness of the PLS model constructed to predict the ethanol test turbidity. Predictive modeling of the short-NIR spectra, following DOSC preprocessing, allowed the prediction of colloidal stability on an unknown test set with an R 2 = 0.80 and a RMSEP = 10.12 using three latent variables. When the data set was restricted to Chardonnay wines alone, the predictive ability improved, with R 2 = 0.85 and RMSEP = 8.90.

An endcapped stationary phase is prepared by thermal immobilization of poly(methyltetradecylsiloxane) (PMTDS) onto a doubly zirconized silica support followed by endcapping using a mixture of hexamethyldisilazane and trimethylchlorosilane. The preparation of the Si-Zr(PMTDS)ec phase shows good repeatability with RSD a3.0% for carbon loadings and column efficiency. This new stationary phase has a lower density of residual hydroxyl groups, according to spectroscopic methods while basic compounds from the Tanaka and Engelhardt test mixtures are eluted with essentially symmetric peaks. Furthermore, the stability of the Si-Zr(PMTDS)ec stationary phase, measured using an accelerated aging test, is twice as great as the stability of a similar nonendcapped phase. The new phase shows promise for the separation of basic pharmaceuticals.

Green fluorescent protein (GFP) is an excellent biosensor as a result of its ability to be easily monitored in a wide variety of applications. Enzymes and proteins have been used as biological indicators to evaluate the immediate efficacy of industrial procedures, such as blanching, pasteurization, and disinfection treatments, as well as to monitor the satisfactory preservation of a product subjected to disinfection or sterilization. The purpose of this work was to study GFP stability in chlorinated water for injection (WFI) and chlorinated buffered solutions at various pH ranges, with and without agitation, to evaluate the exposure time required for chlorine to decrease 90% of its fluorescence intensity (decimal reduction time, D-value, min, 25°C). Fluorescence intensity (Ex/Em max) 394/509 nm) was measured immediately after the addition of GFP (8.0-9.0 µg/mL) into buffered or unbuffered chlorine solutions with or without constant stirring. With solutions constantly stirred, GFP fluorescence decreased abruptly on contact with chlorine in concentrations greater than 150 ppm, with D-values between 1.3 min (147 ppm chlorine) and 1.7 min (183 ppm chlorine). In phosphate buffered chlorine solutions (pH) 7.15 (0.08), GFP retained its structure between 52 and 94 ppm, but protein stability decreased 10-fold when exposed to 110 ppm chlorine. The recovery of GFP fluorescence intensity due to renaturation was observed between 30 and 100 ppm chlorine in WFI (final pH) 11.01 (0.23) without stirring. Stirring enhanced the contact between GFP and chlorine throughout the assay and provided a more accurate D-value evaluation. GFP performed as a suitable fluorescent marker for monitoring disinfection effectiveness.

In an industrial gas-phase polyethylene reactor, the safe operating range of temperature is rather narrow. Even within this temperature range, temperature excursions must be avoided because they can result in low catalyst productivity and significant changes in product properties. In previous work, using a first-principles model, including the recycle stream and the heat exchange system, a PID temperature controller with robust performance was designed via optimization in the frequency domain for different operating points. For the reactor total pressure, ethylene partial pressure, H2/C2 and C4/C2 molar ratios, PI controllers were designed. In the PID temperature controller, if the manipulated variable (cooling water valve opening) saturates then the reactor operates without a feedback temperature controller, leading to oscillatory behaviour and limit cycles. It has been demonstrated that the manipulated variable saturation and the nonlinear dynamic behaviour are removed when auxiliary manipulated variables, obtained by bifurcation analysis, are used in a multivariable control strategy for the reactor temperature control. In this work, two control structures are compared to define the most suitable proposal for implementation in an industrial reactor and the impact of these control structures in the reactor production and in the polymer melt index are analyzed. The first control structure considers the control problem using the designed PID controller for the reactor temperature and includes a switching strategy with a PI controller for the auxiliary manipulated variables. The second control structure considers the control problem also using the designed PID controller for the reactor temperature, however including a MPC controller for the auxiliary manipulated variables.

of ecosystem properties in response to above-ground functional group richness and composition.-Oikos 89: 11-23. While there has been a rapidly increasing research effort focused on understanding whether and how composition and richness of species and functional groups may determine ecosystem properties, much remains unknown about how these community attributes affect the dynamic properties of ecosystems. We conducted an experiment in 540 mini-ecosystems in glasshouse conditions, using an experimental design previously shown to be appropriate for testing for functional group richness and composition effects in ecosystems. Artificial communities representing 12 different above-ground community structures were assembled. These included treatments consisting of monoculture and two-and four-species mixtures from a pool of four plant species; each plant species represented a different functional group. Additional treatments included two herbivore species, either singly or in mixture, and with or without top predators. These experimental units were then either subjected to an experimentally imposed disturbance (drought) for 40 d or left undisturbed. Community composition and drought both had important effects on plant productivity and biomass, and on several below-ground chemical and biological properties, including those linked to the functioning of the decomposer subsystem. Many of these compositional effects were due to effects both of plant and of herbivore species. Plant functional group richness also exerted positive effects on plant biomass and productivity, but not on any of the below-ground properties. Above-ground composition also had important effects on the response of below-ground properties to drought and thus influenced ecosystem stability (resistance); effects of composition on drought resistance of above-ground plant response variables and soil chemical properties were weaker and less consistent. Despite the positive effects of plant functional group richness on some ecosystem properties, there was no effect of richness on the resistance of any of the ecosystem properties we considered. Although herbivores had detectable effects on the resistance of some ecosystem properties, there were no effects of the mixed herbivore species treatment on resistance relative to the single species herbivore treatments. Increasing above-ground food chain length from zero to three trophic levels did not have any consistent effect on the stability of ecosystem properties. There was no evidence of either above-ground composition or functional group richness affecting the recovery rate of ecosystem properties from drought and hence ecosystem resilience. Our data collectively point to the role of composition (identity of functional group), but not functional group richness, in determining the stability (resistance to disturbance) of ecosystem properties, and indicates that the nature of the above-ground community can be an important determinant of the consistency of delivery of ecosystem services.

The instability of supported liquid membranes has been a major impediment to practical applications. To address this shortcoming, we have developed a method to form semi-permeable polyamide skin layers in situ on supported liquid membranes containing an anion-exchange extractant (trioctylamine) and a neutral extractant (tributyl phosphate). These skin layers encapsulate large extractant molecules within the membranes but allow the transport of small species across the membranes. A liquid±liquid interfacial polymerization reaction was employed to form the polyamide skin layers utilizing monomers that are compatible with the extractants. SEM examination of the membranes shows the polyamide skin layer to be about 1 micron thick with pore sizes below resolution. Membranes with polyamide skin layers showed a typical¯ux of 1 mmol/s m 2 of Cr(VI), about half that exhibited by similar membranes without skin layers. # 1998 Elsevier Science B.V. All rights reserved.

In this paper, a vision-based stabilization and output tracking control method for a four-rotor helicopter has been proposed. A novel 2 camera method has been described for estimating the full 6 DOF pose of the helicopter. This two camera system is consisting of a pan-tilt ground camera and an onboard camera. The pose estimation algorithm is compared in simulation to other methods (such as four point method, and a stereo method) and is shown to be less sensitive to feature detection errors on the image plane. The proposed pose estimation algorithm and nonlinear control techniques have been implemented on a remote controlled quadrotor helicopter.

A highly sensitive and selective fluorimetric optode membrane for the determination of ultra trace amounts of Ni 2+ ions was prepared. The plasticized PVC-membrane incorporating potassium tetrakis(p-chlorophenyl)borate (KTpClPB) and 2,5-thiophenylbis(5-tert-butyl-1,3benzexazole) (TTBB), as a highly fluorescent chromoionophore, displays a calibration response for Ni 2+ ions over a wide concentration range of 1.0 × 10 −3 to 1.0 × 10 −8 M. It has a relatively fast response of <40 s. In addition to high stability and reproducibility, and relatively long working lifetime, the sensor possesses good selectivity for nickel ions over several common diverse ions. The fluorescence signal of the optode membrane can be easily recovered by immersion in EDTA solution. The optode was applied successfully to the determination of traces of Ni 2+ ion in edible oil and a wastewater sample from nickel electroplating industries.

A methanol concentration sensor based on twin Nafion membrane electrode assemblies (MEAs) was constructed and characterized by electrochemical methods. Pulsed amperometric detection (PAD) method, using a low frequency (67 mHz) potential waveform of E red (cathodic activation potential) = −0.2 V, E pre-oxd (anodic pre-oxidation potential) = +0.60 V and E det (detection potential) = +0.80 V versus DHE with the same pulse width of 5 s was applied to the sensor to enhance its performance. The response in pulsed mode had better linearity over a wider concentration range than that in potentiostatic mode. Furthermore, using this PAD method, the stability of the sensor was enhanced significantly with a slightly linear degradation rate of 2.9 mA h −1 during long-time test. The performances of the sensor in terms of linearity, low anodic saturation and high stability show its potential application for direct methanol fuel cells.

Г. В. Гавардашвили, Э. Г. Кухалашвили, Т. Г. Супаташвили, И. Р. Иремашвили, И. А. Купарашвили, К. Г. Бзиава, Г. Т. Натрошвили. ОЦЕНКА РИСКОВ ПРОРЫВА ЖИНВАЛИЙСКОЙ ПЛОТИНЫ С УЧЕТОМ МЕТОДА «CAPRA»Georgia is one of the most vulnerable countries to natural disasters within South Caucasus Region. In recent years, the disaster risk has increased due to faulty land-using. Outstanding building codes lead to inadequate building construction. There is a lack of real data on natural disasters and the impact of mudflows, floods, debris flows etc. on land-use planning and prompt actions after above mentioned catastrophes. Therefore, it is important task to carry out assessments of critical structures sensitive to natural threats such as dams and reservoirs. In order to be able to improve the resistance of hydraulic engineering structures it is necessary to utilize a formal risk analysis framework, such as the Critical Asset and Portfolio Risk Analysis (CAPRA) method. The scientific article examin...

The great European dream was to diminish militant nationalism' (Antony Beevor). The future remains open, and some degree of nationalism may be constantly present, but one thing can be expressed with confidence: the European Union has successfully averted conflict within the 'club' and has been a clearly powerful incentive for reconciliation between former enemies as well as bringing democracy in countries formerly ruled by dictatorships. The present crisis apart, the European project remains incomparable. Indeed, this presents an inescapable imperative to any notion of resistance towards the completion of the European integration project. This article focuses on the integration project of the Old Continent's southeastern corner; more specifically, it concerns how a culture-based or incited-conflict can shape a specific cultural setting and, in return, how that culture can be transformed into one of cooperation. The inquiry is placed in the context of the relationship with, and impact of, the EU, which can serve both as example and promoter of such a culture.

Abstract:- This paper details an original method for the stability analysis of mechatronic systems driven by asynchronous machines. The mathematical basis of the method and a few characteristics obtained with an adequate Matlab program are presented. The windows of the program for monitoring of the experimental tests are also depicted. Finally a series of experimental tests and the conclusions confirming the validity of the proposed method are presented. Key-Words:- stability, mechatronic system, asynchronous machine, variable frequency, parameters, software. 1

We consider the stability and performance of a model for networks supporting services that adapt their transmission to the available bandwidth. Not unlike real networks, in our model, connection arrivals are stochastic, each has a random amount of data to send, and the number of ongoing connections in the system changes over time. Consequently, the bandwidth allocated to, or throughput achieved by, a given connection may change during its lifetime as feedback control mechanisms react to network loads. Ideally, if there were a fixed number of ongoing connections, such feedback mechanisms would reach an equilibrium bandwidth allocation typically characterized in terms of its "fairness" to users, e.g., max-min or proportionally fair. In this paper we prove the stability of such networks when the offered load on each link does not exceed its capacity. We use simulation to investigate performance, in terms of average connection delays, for various fairness criteria. Finally, we pose an architectural problem in TCP/IPs decoupling of the transport and network layer from the point of view of guaranteeing connection-level stability, which we claim may explain congestion phenomena on the Internet.

This work is aimed at looking into the flatness control of the crane detailing adopted mechanisms and approaches in order to be able to control this system and to solve problems encountered during its functioning. The control objective is the sway free transportation of the crane s load taking the commands of the crane operator into account. Based on the mathematical model linearizing and stabilizing control laws for the slewing and luffing motion are derived using the input/output linearization approach. The method allows for transportation of the payload to a selected point and ensures minimisation of its swings when the motion is finished. To achieve this goal a mathematical model of the control system of the displacement of the payload has been constructed. A theory of control which ensures swing free stop of the payload is presented. Selected results of numerical simulations are shown. At the end of this work, a comparative study between the real moving and the desired one has been presented.

This paper describes a technical assessment of operating Interprovincial Pipe Line Inc.'s reactivated Line 1 segments from Hardisty, Alberta to Regina, Saskatchewan and active Line 13 segments from Regina to Gretna, Manitoba at a maximum operating pressure equivalent to 80 percent of the test pressure. The assessment addressed the metallurgy and manufacturing methods of the pipe materials, the operating history, the hydrostatic test results, and the analysis of the hydrostatic test failures. From the assessment it was concluded that the existing portions of original Line 1 and all of existing Line 13 that will be used as parts of the proposed New Line 13 are capable of being operated at pressure levels of 80 percent of the 1993/1994 test pressures.

This paper proposes a new H∞ yaw-moment control scheme using brake torque for improving vehicle performance and stability especially in high speed driving. Its characteristics is that only one brake is used for control depending on the vehicle state. Steering angles are modeled as a disturbance input to the system and the controller minimizes the difference between the performance of

ENHANCEMENT OF HEAT AND MASS TRANSFER IN MECHANICALLY-CONSTRAINED ULTRA-THIN FILMS SECTION 1.0-INTRODUCTION AND BACKGROUND Oregon State University (OSU) and the Pacific Northwest National Laboratory (PNNL) were funded by the U.S. Department of Energy to conduct research focused on resolving the key technical issues that limited the deployment of efficient and extremely compact microtechnology based heat actuated absorption heat pumps and gas absorbers. Success in demonstrating these technologies will reduce the main barriers to the deployment of a technology that can significantly reduce energy consumption in the building, automotive and industrial sectors while providing a technology that can improve our ability to sequester CO 2. The

Measurement of seafloor microtopography is rapidly approaching the status as a standardized element of geoacoustic characterization of the sea floor. With the advent of underwater stereo cameras and, recently, multiple-megapixel digital cameras adapted for underwater use, more investigators are measuring seafloor roughness at high resolution for applications to high-frequency acoustic modeling. An assessment of the methodologies used to characterize seafloor roughness, the parameterizations of the characterization of seafloor roughness, and the predictability of seafloor roughness seems appropriate at this time. Use of the roughness power spectrum to characterize seafloor roughness has a wide applicability for acoustic modelers. Currently, the slope and intercept of the regression line through the roughness power spectrum are used to parameterize seafloor roughness for acoustic modeling. Recent availability of digital roughness height datasets allows computation of two-dimensional roughness power spectra at sub-cm resolution. Ideally, these 2-D spectra would make the estimation of 2-D roughness parameters from 1-D roughness parameters unnecessary. Although much seafloor microtopography has been characterized concomitantly with sediment grain size, empirical prediction of roughness from grain size remains problematic. The inherent problem in relating seafloor roughness parameters to grain size is that the sediment-water interface is dynamic. Although seafloor microtopography may be thought to evolve predictably through cycles driven by hydrodynamic and biological processes, the rates of these processes and the resultant bedforms are highly variable. Another aspect of seafloor roughness that needs to be addressed is the character of its power spectrum over several orders of magnitude of spatial dimensions.

This paper presents an experimental study on the homogeneous dispersion of nanoparticles in nanofluids. In this study, various physical treatment techniques based on two-step method, including stirrer, ultrasonic bath, ultrasonic disruptor, and high-pressure homogenizer were systematically tested to verify their versatility for preparing stable nanofluids. Initially carbon black and silver nanoparticles dispersed in base fluids with the presence of surfactant were found to be highly agglomerated with the hydrodynamic diameter of 330 nm to 585 nm, respectively. After both CB and Ag nanofluids were treated by various two-step methods, stirrer, ultrasonic bath, and ultrasonic disrupter was found to do a poor performance in deagglomeration process for the initial particle clusters. However, the high-pressure homogenizer produced the average diameter of the CB and Ag particles of 45 nm and 35 nm, respectively, indicating that among various physical treatment techniques employed in this study, the high-pressure homogenizer was the most effective method to break down the agglomerated nanoparticles suspended in base fluids. In order to prepare another nanofluid with much smaller primary nanoparticles, we also employed a modified magnetron sputtering system, in which the sputtered nanoparticles were designed to directly mix with the running surfactant-added silicon oil thin film formed on a rolling drum (i.e. one-step method). We observed that Ag nanoparticles produced by the modified magnetron sputtering system were homogeneously dispersed and long-term stable in the silicon oil-based fluid, and the average diameter of Ag nanoparticles was found to be~3 nm, indicating that the modified magnetron sputtering system is also an effective one-step method to prepare stable nanofluids.

We introduce a load-balanced adaptive routing algorithm for torus networks, GOAL -Globally Oblivious Adaptive Locally -that provides high throughput on adversarial traffic patterns, matching or exceeding fully randomized routing and exceeding the worst-case performance of Chaos , RLB [14], and minimal routing [8] by more than 40%. GOAL also preserves locality to provide up to 4.6× the throughput of fully randomized routing [19] on local traffic. GOAL achieves global load balance by randomly choosing the direction to route in each dimension. Local load balance is then achieved by routing in the selected directions adaptively. We compare the throughput, latency, stability and hot-spot performance of GOAL to six previously published routing algorithms on six specific traffic patterns and 1,000 randomly generated permutations.

Background-The anisotropy of cardiac tissue is a key determinant of 3D electric propagation and the stability of activation wave fronts in the heart. The electric properties of ventricular myocardium are widely assumed to be axially anisotropic, with activation propagating most rapidly in the myofiber direction and at uniform velocity transverse to this. We present new experimental evidence that contradicts this view. Methods and Results-For the first time, high-density intramural electric mapping (325 electrodes at Ϸ4ϫ4ϫ1-mm spacing) from pig left ventricular tissue was used to reconstruct 3D paced activation surfaces projected directly onto 3D tissue structure imaged throughout the same left ventricular volume. These data from 5 hearts demonstrate that ventricular tissue is electrically orthotropic with 3 distinct propagation directions that coincide with local microstructural axes defined by the laminar arrangement of ventricular myocytes. The maximum conduction velocity of 0.67Ϯ0.019 ms Ϫ1 was aligned with the myofiber axis. However, transverse to this, the maximum conduction velocity was 0.30Ϯ0.010 ms Ϫ1 , parallel to the myocyte layers and 0.17Ϯ0.004 ms Ϫ1 normal to them. These orthotropic conduction velocities give rise to preferential activation pathways across the left ventricular free wall that are not captured by structurally detailed computer models, which incorporate axially anisotropic electric properties. Conclusions-Our findings suggest that current views on uniform side-to-side electric coupling in the heart need to be revised. In particular, nonuniform laminar myocardial architecture and associated electric orthotropy should be included in future models of initiation and maintenance of ventricular arrhythmia. (Circ Arrhythmia Electrophysiol. 2009;2:433-440.)

This paper studies the grasp stability of two classes of threephalanx underactuated fingers with transmission mechanisms based on either linkages or tendons and pulleys. The concept of underactuation in robotic fingers-with fewer actuators than degrees of freedom (DOF)-allows the hand to adjust itself to an irregularly shaped object without complex control strategy and sensors. With a n-phalanx finger, n contacts (one for each phalanx) are normally required to statically constrain the finger. However, some contact forces may be lacking due to either the transmission mechanism, or simply the object size and position. Thus, one may define an i th order equilibrium, when the finger is in static equilibrium with i missing contacts. In this paper, the case for which n = 3 is studied with a particular emphasis on the cases for which i = 1 and i = 2. The fact that some contact forces do not appear or are negative, can lead in some cases to the ejection of the object from the hand, when no equilibrium configuration is achieved.

A two dimensional model of Series RLC circuit is considered for discussion. The system possess only the trivial equilibrium point and local stability conditions are obtained. The phase portraits are obtained for suitable parameter values. Oscillations and damping effects are illustrated with numerical examples.

The accelerated transformation of three azithromycin pseudo-polymorphs (viz. the anhydrous, monohydrate (MH), and dihydrate (DH) forms) at a high temperature and moisture level was examined by near infrared spectroscopy (NIRS). The most marked spectral differences between the pseudo-polymorphs occurred in the 1800-2200 nm region, which corresponds to the first overtone for water. The qualitative analysis of the NIR spectra for the pseudo-polymorphs following storage in a stove at 608C at 100% relative humidity for 60 days suggests that the crystalline forms (viz. the MH and DH) are stable, whereas the amorphous (anhydrous) form evolves to the DH. This was confirmed by determining the amounts of water and DH present in anhydrous azithromycin and the MH by use of partial least-squares regression (PLSR). The method used to quantify the DH in MH samples was developed and validated in accordance with the standards of the International Conference of Harmonization (ICH) and the European Medicines Agency (EMEA) with a view to its subsequent application by the pharmaceutical industry. The limits of detection (LD) and quantitation (LQ) for the DH in MH provided by the NIRS method were consistent with those obtained by X-ray diffraction (XRD) methodology. This testifies to the accuracy of the proposed method.