Critical Parameter

Transport of chlorofluorocarbon (CFC) gases through the unsatu-1995), and groundwater-surface water interactions (Katz rated zone to the water table is affected by gas diffusion, air-water et al., 1995). A critical component in such analyses is the exchange (solubility), sorption to the soil matrix, advective-dispersive transport in the water phase, and, in some cases, anaerobic degrada-consideration of the transport and fate of the CFC tracers tion. In deep unsaturated zones, this may lead to a time lag between in the overlying unsaturated zone. For example, what entry of gases at the land surface and recharge to groundwater. Data are the CFC concentrations in recharge water and how from a Danish field site were used to investigate how time lag is aflong were the CFC gases in the unsaturated zone before fected by variations in water content and to explore the use of simple reaching the groundwater system? The residence time analytical solutions to calculate time lag. Numerical simulations demof a CFC tracer in the unsaturated zone is also called onstrate that either degradation or sorption of CFC-11 takes place, the time lag (Cook and Solomon, 1995). An accurate whereas CFC-12 and CFC-113 are nonreactive. Water flow did not estimate of the age of a groundwater sample also relies appreciably affect transport. An analytical solution for the period with on an accurate estimate of the time lag. a linear increase in atmospheric CFC concentrations (approximately For very shallow unsaturated zones of only a few early 1970s to early 1990s) was used to calculate CFC profiles and time lags. We compared the analytical results with numerical simulations. meters thickness, diffusion and barometric pumping suf-The time lags in the 15-m-deep unsaturated zone increase from 4.2 to ficiently mix the gases in the unsaturated zone so soilbetween 5.2 and 6.1 yr and from 3.4 to 3.9 yr for CFC-11 and CFC-12, gas CFC concentrations are similar to those in the trorespectively, when simulations change from use of an exponential to posphere. The input to the groundwater system is thus a linear increase in atmospheric concentrations. The CFC concentravery close to the atmospheric changes in CFC concentions at the water table before the early 1990s can be estimated by trations. This simple approach often has been used for P. Engesgaard and K.H. Jensen, Geological Institute, Univ. of Copensoil in Germany. A clear damping of the annual changes

The electrical and optical properties of mesoporous gold are compared to those of thin porous gold films and a simulated thin film made by randomly distributing voids in gold, until the voids fill 76% of film volume. All layers are electrically conducting but in some cases the critical percolation thresholds are close to zero, so conduction is possible at very high void content. Significant qualitative differences are apparent between the properties of mesoporous gold, and very thin sputtered gold containing voids, in plasmonic responses at optical frequencies and in dc resistance, both as a function of fill factor. The mesoporous films have an effective plasma frequency determined by void fill factor and structure, but do not support surface plasmons. In contrast thin porous gold layers display optical features associated with localized and de-localized surface plasmons. Sputtered porous gold is 2-dimensional and its percolation threshold requires a "Swisscheese" rather than particle cluster model. Thicker mesoporous layers have critical parameters consistent with very high connectivity, or equivalently large hyper-dimensionality. Our meso-gold samples display various hyper-dimensionalities from 3 to above 10.

respectively. The authors would like to thank George McAndless and Guillermo Escudé for comments, Christian Castro and Matías Gutierrez Girault for assistance, and two anonymous referees for invaluable comments. All remaining errors remain their own. The opinions expressed in this article are entirely those of the authors and do not necessarily reflect those of the Central Bank of Argentina or any other institution with which they are affiliated.

The launch of ADEOS in August 1996 with POLDER, TOMS, and OCTS instruments on board and the future launch of EOS-AM 1 in mid-1998 with MODIS and MISR instruments on board start a new era in remote sensing of aerosol as part of a new remote sensing of the whole Earth system (see a list of the acronyms in the Notation section of the paper). These platforms will be followed by other international platforms with unique aerosol sensing capability, some still in this century (e.g., ENVISAT in 1999). These international spaceborne multispectral, multiangular, and polarization measurements, combined for the first time with international automatic, routine monitoring of aerosol from the ground, are expected to form a quantum leap in our ability to observe the highly variable global aerosol. This new capability is contrasted with present single-channel techniques for AVHRR, Meteosat, and GOES that although poorly calibrated and poorly characterized already generated important aerosol global maps and regional transport assessments. The new data will improve significantly atmospheric corrections for the aerosol effect on remote sensing of the oceans and be used to generate first real-time atmospheric corrections over the land. This special issue summarizes the science behind this change in remote sensing, and the sensitivity studies and applications of the new algorithms to data from present satellite and aircraft instruments. Background information and a summary of a critical discussion that took place in a workshop devoted to this topic is given in this introductory paper. In the discussion it was concluded that the anticipated remote sensing of aerosol simultaneously from several space platforms with different observation strategies, together with continuous validations around the world, is expected to be of significant importance to test remote sensing approaches to characterize the complex and highly variable aerosol field. So far, we have only partial understanding of the information content and accuracy of the radiative transfer inversion of aerosol information from the satellite data, due to lack of sufficient theoretical analysis and applications to proper field data. This limitation will make the anticipated new data even more interesting and challenging. A main concern is the present inadequate ability to sense aerosol absorption, from space or from the ground. Absorption is a critical parameter for climate studies and atmospheric corrections. Over oceans, main concerns are the effects of white caps and dust on the correction scheme. Future improvement in aerosol retrieval and atmospheric corrections will require better climatology of the aerosol properties and understanding of the effects of mixed composition and shape of the particles. The main ingredient missing in the planned remote sensing of aerosol are spaceborne and ground-based lidar observations of the aerosol profiles.

The paper presents a method for minimization of finite state machines (FSMs) with unspecified values of output variables. The proposed method is based on merging of two states. In addition to reduction of the FSM states, the method also allows reducing the number of FSM transitions and FSM input variables. This method enables reducing the number of internal states of the initial FSM by 1.22 times on the average, and by 2.75 times on occasion. An average reduction of the number of FSM transitions makes up 1.32 times, and on occasion may amount to 2.27 times. The comparison of the method with the program STAMINA shows that the offered method allows decreasing the number of FSM transitions by 1.55 times on the average, and by 3.92 times on occasion.

This paper describes the design and testing of a trommel for separation of batteries from solid waste. A trommel is a cylindrical separation device that rotates and performs size separation. It has also been used in areas such as municipal solid waste (MSW) processing, classifying construction and demolition debris, screening mass-burn incinerator ash and compost processing. A trommel has been designed based on size separation to separate household batteries from solid waste, which can then be used as feedstock for alternative applications of solid waste combustion, particularly where the metal content of the product is also a critical parameter, such as the Co-Co process for integrated cement and power production. This trommel has been tested with batches of university office and restaurant wastes against various factors. The recovery efficiency of batteries increases with decreasing inclination angle of the trommel and decreasing rotational speed. A physical characterization of the university solid waste has been performed with a 20-kg sample of the tested waste. It was found that there is a trend of decreasing recovery of batteries with increasing paper composition, and a trend of increasing recovery of batteries with increasing organic materials composition.

Realistic models of past climate and ocean chemistry depend on reconstructions of the Earth's surface environments in the geologic past. Among the critical parameters is the geologic makeup of continental drainage. Here we show, for the present, that the isotope composition of dissolved strontium in rivers increases linearly with the age of bedrock in drainage basins, with the notable exception of the drainage area of Arabia, India, and Southeast Asia that is affected by unusually radiogenic dissolved Sr from the Himalaya. We also demonstrate that the neodymium isotope compositions of suspended matter in rivers as well as clastic sediments deposited along the ocean margins decrease linearly with the bedrock ages of river drainage basins and large-scale continental drainage regions, as determined from digital geologic maps. These correlations are used to calculate the present-day input of dissolved Sr (4.7 × 10 10 mol yr -1 , 87 Sr/ 86 Sr of ∼0.7111) and particulate Nd isotopes (" Nd of approximately -7.3 ± 2.2) to the oceans. The fact that the regionally averaged " Nd of the global detrital input to the global coastal ocean is identical to globally averaged seawater (" Nd of -7.2 ± 0.5) lends credence to the importance of "boundary exchange" for the Nd isotope composition of water masses. Regional biases in source areas of detrital matter and runoff are reflected by the observation that the average age of global bedrock, weighted according to the riverine suspended sediment flux, is significantly younger (∼336 Myr) than the age of global bedrock weighted according to water discharge (394 Myr), which is younger than the average bedrock age of the nonglaciated, exorheic portions of the continents (453 Myr). The observation that the bedrock age weighted according to Sr flux is younger (339 Myr) than that weighted according to water flux reflects the disproportionate contribution from young sedimentary and volcanic rocks to the dissolved Sr load. Neither the isotope composition of the dissolved nor the particulate continental inputs to the ocean provide unbiased perspectives of the lithologic makeup of the Earth's surface. Temporal changes in bedrock geology as well as the shifting focal points of physical erosion and water discharge will undoubtedly have exerted strong controls on temporal and spatial changes in the isotope chemistry of past global runoff and thus seawater.

Background: Recombinant allergens with a native conformation represent an alternative to natural extracts for immunotherapy and diagnostic purposes. Methods: We produced the Der p 2 mite allergen in Pichia pastoris and Escherichia coli. After purification by cation exchange chromatography, recombinant molecules were compared to their natural counterpart based upon structural (disulfide bonds, secondary structure, thermal stability) and immunological properties (antibody reactivity, basophil and T cell activation, tolerance induction in a murine sublingual immunotherapy model). Results: The Der p 2.0101 isoform was confirmed to be prevalent in Dermatophagoides pteronyssinus extracts. It was then produced as a secreted molecule in P. pastoris or refolded from E. coli inclusion bodies. The yeast-expressed rDer p 2 molecule exhibits a natural-like disulfide bridge distribution and secondary structure, whereas the E. coli-derived rDer p 2 presents some heterogeneity in cysteine bonds and...

Micro mechanical milling plays a significant role in fabrication of miniature features in a variety of materials with capability for producing three dimensional (3D) freeform surfaces. A major challenge for micro machining of hardened material is a high tool wear rate and unpredictable tool life. In addition, surface roughness and burr formation are factors to be closely controlled. In this paper, the statistical analysis of critical parameters for micro milling of hardened tool steel is presented. The parameters included spindle speed, depth of cut, ratio of undeformed chip thickness to cutting edge radius and lubrication/environment conditions. The significance of these parameters on surface finish, burr formation and tool wear are reported. The study shows that machining environment is the most significant factor in controlling surface finish and tool wear. While, selection of appropriate spindle speed and the ratio of undeformed chip thickness to cutting edge radius is more critical in limiting burr size. The work reported in this paper is important, because industry needs to know key process variables (KPVs) that are critical in the control of micro machining performance. Additionally, the methodology enabled identification of optimum cutting values for these cutting parameters within the identified process window.

In this computational study we consider a generalized minimal model structure for the intravenously infused insulin-blood glucose dynamics, which can represent a wide variety of diabetic patients, and augment this model structure with a glucose rate disturbance signal that captures the aggregate effects of various internal and external factors on blood glucose. Then we develop a model-based, switching controller, which attempts to balance between optimal performance, reduced computational complexity and avoidance of dangerous hypoglycaemic events. We evaluate the proposed algorithm relative to the widely studied proportional-derivative controller for the regulation of blood glucose with continuous insulin infusions. The results show that the proposed switching control strategy can regulate blood glucose much better than the proportional-derivative controller for all the different types of diabetic patients examined. This new algorithm is also shown to be remarkably robust in the eve...

Red, hematite-bearing sedimentary rocks are an important source of paleomagnetic data, particularly for continental apparent polar wander paths during the Paleozoic. This study presents magnetic anisotropy data from the Mississippian Mauch Chunk Formation of eastern Pennsylvania, indicating that these red beds have suffered from a significant amount of paleomagnetic inclination shallowing. Fourteen oriented block samples were collected from normal and reversed polarity strata identified in a previous study. Thermal demagnetization isolated the characteristic remanent magnetization at seven normal polarity horizons at unblocking temperatures greater than 670°C (mean direction, D = 354.0°, I = À18.4°, a 95 = 10.2°). Anisotropy of remanence measurements (anisotropy of isothermal remanent magnetization and thermal remanent magnetization) indicate a bedding parallel, foliated magnetic fabric with foliations ranging from 1.1 to 1.35. Thermal demagnetization at 670°C of the isothermal remanent magnetization isolates the magnetic fabric of the characteristic remanence-carrying grains and indicates stronger foliations (1.15-1.48). Anisotropy of magnetic susceptibility (AMS) also indicates bedding parallel magnetic foliations of 1.01-1.04, typical of red beds. Chemical leaching isolates the AMS of the characteristic remanence-carrying grains to range from 1.02 to 1.07. This AMS fabric was used to correct the characteristic remanence inclination isolated by thermal demagnetization. The critical parameter needed for an accurate inclination correction, the individual particle anisotropy a c , was determined from the correlation between the normalized principal axes of remanence and susceptibility anisotropy to be 1.06. The corrected Mauch Chunk direction, D = 354.5°, I = À56.4°r esults in a corrected Mauch Chunk Formation paleopole (12°N, 108°E) that is consistent with a European igneous paleopole.

The role of excess molar enthalpies (H E m ) in the supercritical antisolvent (SAS) micronizations using dimethylsulfoxide (DMSO) as the polar solvent was investigated. Excess molar enthalpies for CO 2 + DMSO mixtures were measured using an isothermal high-pressure flow calorimeter under conditions of temperature and pressure typically used in SAS micronizations. In most cases, mixtures showed very exothermic mixing. A local temperature increase can be expected in the precipitation chamber as a consequence of the heat evolved when CO 2 dissolves in DMSO. Based on the H E m measurements, local temperature increases were calculated and shown to explain immiscibility of CO 2 and DMSO and agglomerated or irregular particles for average temperature and pressure conditions where complete miscibility and uniform particles could have been expected. H E m data were also discussed in terms of molecular interactions, phase equilibria, density and critical parameters previously reported for CO 2 + DMSO.

Mixtures of supercritical CO 2 and N,N-dimethylformamide (DMF) are very often involved in supercritical fluid applications and their thermodynamic properties are required to understand and design these processes. Excess molar enthalpies (H E m ) for CO 2 + DMF mixtures were measured using an isothermal high-pressure flow calorimeter under conditions of temperature and pressure typically used in supercritical processes: 313.15 and 323.15 K at 9.00, 12.00, 15.00 and 18.00 MPa and 333.15 K at 9.00 and 15.00 MPa. The Peng-Robinson and the Soave-Redlich-Kwong equations of state were used in conjunction with the classical mixing rules to model the literature vapor-liquid equilibrium and critical data and the excess enthalpy data. In most cases, CO 2 + DMF mixtures showed very exothermic mixing and excess molar enthalpies exhibited a minimum in the CO 2 -rich region. The lowest H E m value (-4526 J mol -1 ) was observed for a CO 2 mole fraction value of 0.713 at 9.00 MPa and 333.15 K. On the other hand, H E m at 9.00 MPa and 323.15 and 333.15 K varies linearly with CO 2 mole fraction in the two-phase region where a gaseous and a liquid mixture of fixed composition are in equilibrium. The effects of pressure and temperature on the excess molar enthalpy are large. For a given mole fraction, mixtures become less exothermic as pressure increases or temperature decreases. These excess enthalpy data were analyzed in terms of molecular interactions, phase equilibria, density and critical parameters previously reported for CO 2 + DMF. All throughout this paper, the key concepts and modeling tools originate from the work of van der Waals: the paper is intended as a small piece of recognition of van der Waals overwhelming contributions to thermodynamics.

Anaerobic hydrogen production from organic wastewater, an emerging biotechnology to generate clean energy resources from wastewater treatment, is critical for environmental and energy sustainability. In this study, hydrogen production, biomass growth and organic substrate degradation were comprehensively examined at different levels of two critical parameters (chemical oxygen demand (COD) and pH). Hydrogen yields had a reverse correlation with COD concentrations. The highest specific hydrogen yield (SHY) of 2.1 mole H 2 /mole glucose was achieved at the lowest COD of 1 g/L and decreased to 0.7 mole H 2 / mole glucose at the highest COD of 20 g/L. The pH of 5.5-6.0 was optimal for hydrogen production with the SHY of 1.6 mole H 2 /mole glucose, whereas the acidic pH (4.5) and neutral pH (6.0-7.0) lowered the hydrogen yields. Under all operational conditions, acetate and butyrate were the main components in the liquid fermentation products. Additionally, a comprehensive kinetic analysis of biomass growth, substrate degradation and hydrogen production was performed. The maximum rates of microbial growth (m m ) and substrate utilization (R su ) were 0.03 g biomass/g biomass/day and 0.25 g glucose/g biomass/day, respectively. The optimum pH for the rate of hydrogen production (R H2 ) and SHY were 5.89 and 5.74 respectively. Based on the kinetic analysis, the highest R H2 and SHY for batchmode anaerobic hydrogen production systems were projected to be 13.7 mL/h and 2.32 mole H 2 /mole glucose.

Microelectromechanical systems (MEMS) use silicon based dielectric films such as SiO 2 and Si 3 N 4 for providing insulation. In capacitive transducers, these layers are used as insulation layers for capacitive actuators to prevent short-circuiting of electrodes by contact of electrodes and in case of touchmode capacitive pressure sensors (TMCPS), the dielectric layer provides for overload protection and provides for operation in the pressure ranges in which the diaphragm comes in contact with dielectric. The pressure at which diaphragm just touches the dielectric is referred to as touch-point pressure. In case of actuator, pull-in voltage is a critical parameter that decides the onset of instability in operation of the device. Silicon based dielectric thin films have the tendency to store or trap static charges, the presence of which alters the ideal behaviour of dielectrics. These trapped static charges introduced due fabrication processes; handling and operation affect the operation of capacitive transducers by influencing the pullin voltage and by affecting the touch-point pressure. This paper presents a novel methodology, which predicts the pull-in voltage and touch-point pressure in presence of the static charges in a dielectric. The method proposed is less complex and less time consuming. Closed form expressions have been derived for pull-in voltage, touch-point pressure and critical displacement in presence of static charges. The results are compared with those obtained by experiment.

A closed form model for evaluating touch point pressure and pull-in voltage of clamped square diaphragm with residual stress is proposed. Square diaphragms are used in numerous applications. The design parameters for all these structures are pull-in voltage and/or touchpoint pressure. The materials employed for fabricating diaphragms for these structures are p+ doped silicon, polysilicon, silicon nitride, polyimide etc. All these materials have residual stress, which influences the behavior of the transducer. In addition to this, a capacitive transducer may or may not employ an intervening layer of dielectric on the fixed electrode. Closed form expressions for evaluating touch-point pressure and pull-in voltage have been derived for such a structure by means of semianalytical model. The method proposed is less complex and less time consuming in comparison with FEM tools.

MEMS (Microelectromechanical system) capacitive based pure bending strain sensor is presented for use in monitoring the progress in healing of the knee after injury or after knee replacement. The sensor is designed to monitor the progress in knee bending during physiotherapy. The sensor is designed and simulated in COMSOL Multiphysics® software. The capacitive structure of sensor is composed of two parallel plates with narrow gap between them and conjoint end. The sensor is mounted on the cantilever, which responds to the strain. The dimension of sensor is very small as compared to that of cantilever beam. Therefore, its simulation is a great challenge for us. For simulation, two methods were used. First consists of only simulating the sensor by having the effect of cantilever displacement on it. Second, consists of simulating the cantilever and sensor as the two components in same model. The mechanism of sensing is based on the concept of change in capacitance due to change in gap ...

There are a number of MEMS structures that make use of diaphragms. The deformation of the diaphragm for the purpose of actuation and transduction can be brought about by application of voltage and/or pressure or any other mechanical excitation like acceleration, force, etc. The amount of deformation can be measured by changes in the capacitance between the diaphragm and the fixed electrode. The gap between the electrodes can be an air gap or can have an intervening layer of the dielectric on the fixed electrode along with the air gap. The pull-in voltage and touch-point pressure along with the structural and material properties are critical parameters that decide the behavior of the actuator/transducer. This paper presents a simple methodology, which is capable of representing small deflection of diaphragm with pressure, and/or applied voltage. The method proposed is less complex and less time consuming in comparison with FEM tools. Closed form expressions have been derived for pull-in voltage with/without dielectric between the two electrodes and critical distance for pull-in. The closed form expressions for touch-point pressure have also been derived. The results are compared with those obtained by simulation as well as experiment.

Microelectromechanical systems (MEMS) use silicon based dielectric films such as SiO 2 and Si 3 N 4 for providing insulation. In capacitive transducers, these layers are used as insulation layers for capacitive actuators to prevent short-circuiting of electrodes by contact of electrodes and in case of touchmode capacitive pressure sensors (TMCPS), the dielectric layer provides for overload protection and provides for operation in the pressure ranges in which the diaphragm comes in contact with dielectric. The pressure at which diaphragm just touches the dielectric is referred to as touch-point pressure. In case of actuator, pull-in voltage is a critical parameter that decides the onset of instability in operation of the device. Silicon based dielectric thin films have the tendency to store or trap static charges, the presence of which alters the ideal behaviour of dielectrics. These trapped static charges introduced due fabrication processes; handling and operation affect the operation of capacitive transducers by influencing the pullin voltage and by affecting the touch-point pressure. This paper presents a novel methodology, which predicts the pull-in voltage and touch-point pressure in presence of the static charges in a dielectric. The method proposed is less complex and less time consuming. Closed form expressions have been derived for pull-in voltage, touch-point pressure and critical displacement in presence of static charges. The results are compared with those obtained by experiment.

This paper presents an analytical and numerical investigation of a circularly polarized beam propagating along the static magnetic field parallel to oscillating magnetic field in plasma at relativistic intensities. In the high intensity regime, such a magnetic field is created by the pulse itself. The authors have identified three regimes of propagation taking into account the relativistic mass correction. Based on WKB and paraxial ray theory, an appropriate expression for a dielectric tensor has been evaluated in the presence of an externally applied magnetic field. The natural electromagnetic modes are circularly polarized. Consequently, extraordinary and ordinary modes propagate, which are significantly affected due to the relativistic mechanism. The regimes are characterized by dimensionless power and beamwidth, characterizing the nature of propagation as steady divergence, oscillatory divergence and self-focusing. Numerical computations are presented and discussed for typical parameters of laser plasma interaction; defined through critical parameters, namely cyclotron-to-beam frequency ( c ), plasma-to-beam frequency ( p ) and beam power for arbitrary large intensities.

The Widom line and the liquid–liquid critical point of water in the deeply supercooled region are investigated via computer simulation of the TIP4P/2005 model. The Widom line has been calculated as the locus of compressibility maxima. It is quite close to the experimental homogeneous nucleation line and, in the region studied, it is almost parallel to the curve of temperatures of maximum density at fixed pressure. The critical temperature is determined by examining which isotherm has a region with flat slope. An interpolation in the Widom line gives the rest of the critical parameters. The computed critical parameters are \documentclass[12pt]{minimal}\begin{document}$T_c\!=\!193$\end{document}Tc=193 K, \documentclass[12pt]{minimal}\begin{document}$p_c\!=\!1350$\end{document}pc=1350 bar, and \documentclass[12pt]{minimal}\begin{document}$\rho _c\!=\!1.012$\end{document}ρc=1.012 g/cm \documentclass[12pt]{minimal}\begin{document}$^3$\end{document}3. Given the performance of the model fo...

This paper reports a novel capacitive detection method, called the sideband-ratio (SBR) detection, which is robust to variations of such critical parameters as the nominal capacitance, frequency, and amplitude of the probing voltage and gain of the transimpedance amplifier. The approach constructively utilizes the inherent nonlinearity of parallel-plate sense capacitors in order to measure the amplitude of sinusoidal motion. In the case of parallel-plate detection signal, multiple harmonics exist and each carry information about the amplitude of mechanical motion. The SBR method robustly extracts the amplitude of motion from the ratio of multiple sidebands. This paper presents theoretical background and analysis of this nonlinear measurement method. A real-time measurement algorithm is implemented in software and simulated. Feasibility of the developed approach is demonstrated experimentally.

Recent results on heavily irradiated natural and synthetic NaCl crystals give evidence for the formation of large vacancy voids, which were not addressed by the conventional Jain±Lidiard model of radiation damage in alkali halides. This model was constructed to describe metal colloids and dislocation loops formed in alkali halides during earlier stages of irradiation. We present a theory based on a new mechanism of dislocation climb, which involves the production of V F centers (self-trapped hole neighboring a cation vacancy) as a result of the absorption of excess H centers. Voids are shown to arise due to the reaction between F and V F centers at the surface of halogen bubbles. Critical parameters associated with the bubble-to-void transition are evaluated. Voids can grow to sizes exceeding the mean distance between colloids and bubbles, eventually absorbing them, and, hence, igniting a back reaction between the halogen gas and metal. The amount of radiation damage in alkali halides should be evaluated with account of void formation, which strongly aects the radiation stability of material.

In spite of the larger performance gain such as higher throughput and almost zero packet retransmissions compared to TCP Reno, TCP Vegas still has a few obstacles for it to be deployed in the Internet. Studies have shown unfair treatment to Vegas connections when they compete with Reno connections. Other issues identified with TCP Vegas are problems of rerouting, persistent congestion, and discrepancy in flow rate tied with starting times and link bandwidth. We reinvestigate these issues and propose modifications to the congestion avoidance mechanism of the TCP Vegas, with the slow-start and congestion recovery algorithms of Vegas remaining untouched. Unlike the solutions proposed in the recent past to deal with some of these issues, our solution is neither dependent on any critical parameter values nor on the buffer management scheme at the routers (e.g., RED). Our experiments show that the modified TCP Vegas (Vegas-A) is able to obtain a fairer share of the network bandwidth when competing with other TCP flows. We also show that Vegas-A can tackle rerouting issues and rectify Vegas's bias against higher bandwidth flows. At the same time, our experiments prove that Vegas-A preserves the properties of Vegas that have made it a noteworthy protocol.

While it has been shown that TCP Vegas provides better performance compared to TCP Reno, studies have identified various issues associated with the protocol. We propose modifications to the congestion avoidance mechanism of the TCP Vegas to overcome these limitations. Unlike the solutions proposed in the past, our solution, named TCP Vegas-A, is neither dependent on optimising any critical parameter values nor on the buffer management scheme implemented at the routers and hence can be implemented solely at the end host. Our simulation experiments over wired as well as over geosynchronous and lower earth orbit satellite links show that TCP Vegas-A is able to overcome several of the identified problems-it can obtain a fairer share of the network bandwidth in wired and satellite scenarios, tackle rerouting issues, rectify Vegas's bias against higher bandwidth flows and prevail over fluctuating RTT conditions of a lower earth orbit satellite link. At the same time, Vegas-A is able to preserve the unique properties of Vegas that had made it a noteworthy protocol.

The application of laser cladding to build complex shape steel tools by multilayer deposition is attracting considerable attention. Due to the fast cooling rates attained diffusive solid-state transformations are suppressed, but martensitic transformations may occur. As successive clad tracks are overlapped, the associated thermal input is driven by heat conduction to the previously deposited layers. As a result, these layers undergo a succession of anisothermal cycles that may lead to complex phase transformations, which modify the properties of the deposited material. In this paper, an innovative mathematical model is described, which combines solid state phase transformation kinetics with a finite element heat transfer model to simulate the phase transformations and properties changes occurring during laser free-form manufacturing.

The laser-driven punched-out scheme, which has been proposed for supplying minimum-mass tin fuels at a high repetition rate, was investigated for use in an extreme ultraviolet (EUV) light source. The density profile of punched-out tin fuel is a critical parameter for validating applicability of this scheme. An EUV backlight technique was developed to measure the density profile and fine structure. Experimental results reveal that a punched-out target does not remain its initial thin shape, but expands into a rarefied gas and liquid and small particles under the present target and laser conditions.

RHESSI uses nine Rotating Modulation Collimators (RMCs) for imaging, each consisting of a pair of grids mounted on the rotating spacecraft. The angular resolutions range from 2.3 arcsec to 3arcmin. The relative twist between the two grids of each pair is the most critical parameter. It must be less than 20 arcsec for the finest grid. After precision alignment, it is monitored by the Twist Monitoring System (TMS) to a few arcsec. The Sun-pointing must be known better than 0.4 arcsec for the image reconstruction. This is achieved by the Solar Aspect System (SAS), which consists of a set of three Sun sensors. Each sensor is focusing the filtered Sunlight onto a linear CCD. The onboard Aspect Data Processor (ADP) selects the 6 limb positions, which over-define the pointing offset of the Sun center with respect to the imaging axis of the imager. The Roll Angle System (RAS) continuously measures the roll angle of RHESSI within arcmin accuracy. The RAS is a continuously operating CCD star scanner. The time of the passage of a star image over the CCD is recorded and defines the roll angle, comparing its pixel position and amplitude with a star map.

The capacity of mobile ad hoc network (MANET) is typically determined by the size of network, routing protocol, mobility and the interactions that occur between the nodes. Moreover, these critical parameters cause the loss rate that has severed impact on the performance of the MANET. This situation even becomes worst when these critical parameters are chosen inappropriately. This paper presents an analytical model that incorporates most of the critical parameters that can influence the capacity of MANET. Based on the analytical model, an efficient 3phase algorithm is designed to optimize the performance of MANET in terms of an increased capacity and the reduced transmission delay. The proposed 3-pahse algorithm considers both delay-tolerant and delay-sensitive network traffics. In addition, the 3-phase algorithm can be used to approximate both the best and worst case capacities of MANET with the relaying and non-relaying nodes.

This paper presents a synthesis of robustness evaluation on power RF LDMOS devices and its relation with electrical and physical behaviours after RF life-tests. It is important to understand the physical degradation mechanism effects and the liaison on drifts of critical electrical parameters after life ageing tests, in I-V such as threshold voltage (Vth), the feedback capacitance (Crss) in C-V and the S-parameter (S21) in RF. It shows with tracking of set parameters that Hot Carrier Injection (HCI) phenomenon appears. It is the main cause for device degradation leading to the interface state generation (traps), which results in a build up of negative charge at Si/SiO2 interface. More interface states are created due to a located maximum impact ionization rate at the gate edge. Such simulations correctly take into account interactions coupled between electrical, thermal and RF behaviours in device inside using the FEM method. A numerical model (Silvaco-Atlas) was used to confirm deg...

The recent developments in liquid chromatography (LC) are mainly dedicated to both system miniaturization (micro-, capillary-, and nano-LC) and analysis time decrease (fast-, and ultra-fast-LC). For the latter, several strategies can be used, and high temperature liquid chromatography (HTLC) seems very promising and easy to implement, especially in miniaturized system. In LC, the evaporative light scattering detector (ELSD) is considered an attractive alternative to conventional detector such as UV-vis due to its versatility and quasi-universality. Therefore, the compatibility of ELSD with -LC and -HTLC was investigated for several pharmaceutical compounds of interest. The nebulization process appeared to be the most critical parameter for performing the coupling and maintaining an efficient separation. Therefore, appropriate modifications in the nebulization cell geometry were brought to make ELSD fully compatible with -LC. The impact of optimized nebulization cell on chromatographic performance was evaluated in terms of efficiency and sensitivity. Finally, highly efficient, sensitive and fast separations of pharmaceutical drugs were performed with both techniques and the customized nebulization cell design.

In previous studies, non local effects have been evidenced and modeled [1, 2]. The fluidity is the number of rearrangement of droplets by unit of time, and appears to be a critical parameter to describe experimental data. In the present work, flows of flocculated and non-flocculated concentrated emulsions within Hele-Shaw cells are investigated. Fast confocal imaging is used to determine fluidity and cooperative length, and the Kinetic Elasto-Plastic model is challenged for systems with different interdroplet attractions[4pt] [1] J. Goyon, A. Colin, G. Olvarlez, A. Ajdari, and L. Bocquet, Nature 454 (2008) 84-87.[0pt] [2] L. Bocquet, A. Colin, and A. Ajdari, PRL 103 (2009).

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... The external traffic source attached to each node generates Poisson distributed packet arrivals with average traffic load λ/N (packets/slot) where N is the number of nodes in the network, and λ is the total external traffic load. ... External arrival rate, λ (packet/slot) ...

A critical problem related to kernel-based methods is the selection of an optimal kernel for the problem at hand. The kernel function in use must conform with the learning target in order to obtain meaningful results. While solutions to estimate optimal kernel functions and their ...

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parts of the field investigations. The PhD thesis comprises a synopsis of the work presented in two published papers, two manuscripts prepared for scientific journals and a technical note. In the synopsis of the thesis the papers are referred to by the names of the authors and the Roman numerals (e.g. Damgaard et al., III). The papers included in the thesis are:

We consider an interacting particle system on a graph which, from a macroscopic point of view, looks like Z d and, at a microscopic level, is a complete graph of degree N (called a patch). There are two birth rates: an inter-patch one λ and an intra-patch one φ. Once a site is occupied, there is no breeding from outside the patch and the probability c(i) of success of an intra-patch breeding decreases with the size i of the population in the site. We prove the existence of a critical value λcr(φ, c, N) and a critical value φcr(λ, c, N). We consider a sequence of processes generated by the families of control functions {cn} n∈N and degrees {Nn} n∈N ; we prove, under mild assumptions, the existence of a critical value ncr(λ, φ, c). Roughly speaking we show that, in the limit, these processes behave as the branching random walk on Z d with inter-neighbor birth rate λ and on-site birth rate φ. Some examples of models that can be seen as particular cases are given.

Ion-driven fast ignition (IFI) may have significant advantages over electron-driven FI due to the potentially large reduction in the amount of energy required for the ignition beam and the laser driver. Recent experiments at the Los Alamos National Laboratory’s Trident facility employing novel Au flat-top cone targets have produced a fourfold increase in laser-energy to ion-energy efficiency, a 13-fold increase in the number of ions above 10MeV, and a few times increase in the maximum ion energy compared to Au flat-foil targets. Compared to recently published scaling laws, these gains are even greater. If the efficiency scales with intensity in accordance to flat-foil scaling, then, with little modification, these targets can be used to generate the pulse of ions needed to ignite thermonuclear fusion in the fast ignitor scheme. A proton energy of at least 30MeV was measured from the flat-top cone targets, and particle-in-cell (PIC) simulations show that the maximum cutoff energy may...

To investigate the role of the critical parameters in adaptation of proteins to low temperatures, a comparative systematic analysis was performed. Several parameters were proposed to have contribution to cold adaptation of proteins. Among proposed parameters, total values of residual structure states, secondary structure states and oligomeric states were alike in both psychrophilic and mesophilic proteins. In addition, our results provided new quantitative information about the trends in the substitution preference of Ile, Phe, Tyr, Lys, Arg, His, Glu and Leu with most of amino acids and substitution avoidance of Gly, Thr and Ala with most of amino acids. These findings would help future efforts propose a strategy for designing psychrophilic proteins.

In this paper we investigate the process margin for the 100nm half-pitch double exposure KrF lithography using binary masks for different illumination settings. The application of Double Exposure Lithography (DEL) would enlarge the capability of 248 nm exposure technique to smaller pitch e.g. for the integration of dedicated layers into 0.13 µm BiCMOS with critical dimension (CD) requirements exceeding the standard 248 nm lithography specification. The DEL was carried out with a KrF Scanner (Nikon S207D, NA Lens = 0.82) for a critical dimension (CD) of 100nm half pitch. The chemical amplified positive resists SL4800 or UV2000 (Rohm & Haas) with a thickness of 325nm were coated on a 70 nm AR10L (Rohm & Haas) bottom anti-reflective coating (BARC). With a single exposure and using binary masks it is not possible to resolve 100nm lines with a pitch of 200 nm, due to the refraction and the resolution limit. First we investigated the effect of focus variation. It is shown that the focus difference of 1 st and 2 nd exposure is one critical parameter of the DEL. This requires a good focus repeatability of the scanner. The depth of focus (DOF) of 360 nm with the coherence parameter σ = 0.4 was achieved for DEL with SL4800 resist. The influence of the better resist resolution of UV2000 on the process window will be shown (DOF = 460 nm). If we change the focus of one of the exposures the CD and DOF performance of spaces is reduced with simultaneous line position changing. Second we investigated the effect of different illumination shapes and settings. The results for conventional illumination with different values for σ and annular illumination with σ inner = 0.57 and σ outer = 0.85 will be shown. In summary, the results show that DEL has the potential to be a practical lithography enhancement method for device fabrication using high NA KrF tool generation.

This work couples a computational structural dynami cs (CSD) code to model the control system complex kinematics and a comprehensive analysis code to com pute both the rotor aeromechanics and the helicopte r dynamic behavior. A weak coupling approach is set-u p to exchange the data between the high-fidelity structural calculations LMS Virtual.Lab Motion® and the in-house comprehensive code HOST. The CSD coupling strategy that is set-up in this paper diff ers from most other works in that the coupled eleme nt, in particular the swashplate, is in the middle of the kinematic chain (see Figure 1). Such a coupling hel ps benefit from the high-fidelity modelling of the con trol system to account for complex kinematics, swas hplate elasticity, and fittings on a flexible fuselage. Th is initial coupling development helps improve dynam ic loads calculations and may then lead to better stability predictions of the helicopter rotor-airframe coupli ngs. NOTATIONS ∗ , ∗ State matrices (Damping a...

This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited.

The SpW-RTC can play the role of payload data processor inside the Instrument Controller Unit (ICU). It can receive payload data from instruments, process them and send down via SpW. Its several programmable interfaces allow RTC to acquire analogue and digital data, generated by peripherals. The on-chip interfaces have DMA capability, thus data transfers between SpW links and i.e FIFO can sustain high bitrates. The CAN bus allows the On-board Computer (OBC) to monitor and control the SpW-RTC device that acts as a remote terminal.