Double Input Research Articles

Development and testing of RF double window input couplers for TESLA

More and more accelerators are built with superconducting cavities operating at cryogenic temperatures. A possible window failure might result in contamination of the cavity surface and degrade the accelerating performance. A cost effective design and fabrication method for a new coupler has been developed by AMAC. This new design is an alternative to the present TESLA cylindrical ceramic windows layout. The new design includes two planar disc windows separated by a vacuum space. An alternative design option proposes filling dry nitrogen gas in between the two ceramic windows. Furthermore the new design is optimized for RF input power, taking into consideration the possible requirements of the TESLA superstructure layout. Two prototype couplers with this design have been fabricated. The couplers are being tested on the high power test stand at DESY, Germany. This paper describes the new coupler design and discusses the first measured results.

Simulation of CO2 concentrations, temperature, and stratification in Lake Nyos for different degassing scenarios

A large gas cloud erupted unexpectedly in 1986 from Lake Nyos, the larger of the two Cameroonian “Killer Lakes,” with devastating consequences. Regular monitoring subsequently revealed that the deep water of the lake was gradually recharged with CO2. To preclude a similar event in the future, a degassing pipe was installed in the lake in 2001. In the present study a one‐dimensional model is used to predict the effects of this pipe and other degassing options on the CO2 concentrations and the stratification within the lake for the next 50 years. The results of the simulations show that without degassing, total CO2 content would reach the preeruption value within a few decades. The presently installed pipe is sufficient to reduce CO2 pressures in the entire water column above the pipe inlet to <5 bar within 10 years, and a steady state is reached within 50 years. Depending on the assessment of the risk due to the gas currently remaining in the lake and the costs involved, the installation of additional pipes could be considered (1) to remove the gas more quickly and (2) as a backup for long‐term failures and maintenance. Once the steady state is reached, degassing with one pipe is a practicable long‐term solution which can also be used for monitoring the approximate deep water CO2 concentrations by nonprofessionals. Assuming a doubled deep water input in the future as an upper limit of the expected source strength, the pipe is still able to prevent a CO2 accumulation. As a side effect, the degassing operation strongly changes the stratification in the lake. It transforms the lake from a meromictic to an oligomictic system and gradually removes the dissolved salts from the lake.

Microbial community utilization of added carbon substrates in response to long-term carbon input manipulation

The chemical composition and quantity of plant inputs to soil are primary factors controlling the size and structure of the soil microbial community. Little is known about how changes in the composition of the soil microbial community affect decomposition rates and other ecosystem functions. This study examined the degradation of universally 13C-labeled glucose, glutamate, oxalate, and phenol in soil from an old-growth Douglas-fir ( Pseudotsuga menziesii)—western hemlock ( Tsuga heterophylla) forest in the Oregon Cascades that has experienced 7 y of chronic C input manipulation. The soils used in this experiment were part of a larger Detritus Input and Removal Treatment experiment and have received normal C inputs (control), doubled wood inputs, or root and litter input exclusion (no inputs). Soil from the doubled wood treatment had a higher fungal:bacterial ratio, and soil from the no inputs treatment had a lower fungal:bacterial ratio, than the control soil. Differences in the utilization of the compounds added to the field-manipulated soils were assessed by following the 13C tracer into microbial biomass and respiration. In addition, 13C-phospholipid fatty acids (PLFA) analysis was used to examine differential microbial utilization of the added substrates. Glucose and glutamate were metabolized similarly in soils of all three litter treatments. In contrast, the microbial community in the double wood soil respired more added phenol and oxalate, whereas microbes in the no inputs soil respired less added phenol and oxalate, than the control soil. Phenol was incorporated primarily into fungal PLFA, especially in soil of the double wood treatment. The addition of all four substrates led to enhanced degradation of soil organic matter (priming) in soils of all three litter treatments, and was greater following the addition of phenol and oxalate as compared to glucose and glutamate. Priming was greater in the no inputs soil as compared to the control or doubled wood soils. These results demonstrate that altering plant inputs to soil can lead to changes in microbial utilization of C compounds. It appears that many of these changes are the result of alteration in the size and composition of the microbial community.

High-gain differential CMOS transimpedance amplifier with on-chip buried double junction photodiode

An integrated fully differential CMOS transimpedance amplifier (TIA) with buried double junction photodiode input is described. The TIA features a variable high transimpedance gain (250 k/spl Omega/ to 2.5 M/spl Omega/), large DC photocurrent rejection capability (>55 dB) and low input referred noise density at 100 kHz (2pA//spl radic/Hz).

Detrital Controls on Soil Solution N and Dissolved Organic Matter in Soils: A Field Experiment

We established a long-term field study in an old growth coniferous forest at the H.J. Andrews Experimental Forest, OR, USA, to address how detrital quality and quantity control soil organic matter accumulation and stabilization. The Detritus Input and Removal Treatments (DIRT) plots consist of treatments that double leaf litter, double woody debris inputs, exclude litter inputs, or remove root inputs via trenching. We measured changes in soil solution chemistry with depth, and conducted long-term incubations of bulk soils from different treat- ments in order to elucidate effects of detrital inputs on the relative amounts and lability of different soil C pools. In the field, the addition of woody debris increased dissolved organic carbon (DOC) concentrations in O-horizon leachate and at 30 cm, but not at 100 cm, compared to control plots, suggesting increased rates of DOC retention with added woody debris. DOC concentrations decreased through the soil profile in all plots to a greater degree than did dissolved organic nitrogen (DON), most likely due to preferential sorption of high C:N hydrophobic dissolved organic matter (DOM) in upper horizons; percent hydrophobic DOM decreased significantly with depth, and hydrophilic DOM had a much lower and less variable C:N ratio. Although laboratory extracts of different litter types showed differences in DOM chemistry, percent hydrophobic DOM did not differ among soil solutions from different detrital treatments in the field, suggesting that microbial processing of DOM leachate in the field consumed easily degradable components, thus equalizing leachate chemistry among treatments. Total dissolved N leaching from plots with intact roots was very low (0.17 g m 2 year 1 ), slightly less than measured deposition to this very unpolluted forest (0.2 g m 2 year 1 ). Total dissolved N losses showed significant increases in the two treatments without roots whereas concentrations of DOC decreased. In these plots, N losses were less than half of estimated plant uptake, suggesting that other mechanisms, such as increased microbial immobilization of N, accounted for retention of N in deep soils. In long-term laboratory incubations, soils from plots that had both above- and below-ground litter inputs excluded for 5 years showed a trend towards lower DOC loss rates, but not lower respiration rates. Soils from plots with added wood had similar respiration and DOC loss rates as control soils, suggesting that the additional DOC sorption observed in the field in these soils was stabilized in the soil and not readily lost upon incubation.

Phase-locked carrier-envelope-offset frequency at 1560 nm

We report on the measurement of an Erbium-fiber oscillator's carrier-envelope-offset frequency using an extruded SF6 photonic crystal fiber for the generation of a more than two octave-spanning supercontinuum from 400 nm to beyond 1750 nm. A modified type of f-2f-interferometer was employed, beating the frequency doubled input signal of the fiber oscillator with the supercontinuum to generate the carrier-envelope-offset beat. Controlling the fiber oscillator's pump power with an electronic feedback loop, we phase-locked the carrier-envelope-offset frequency to an external reference source. The resulting residual phase excursions correspond to fractional frequency instabilities of the oscillator's frequency comb of the order of 10(-16) for averaging times longer than 10 s.

Control of linear systems using piecewise continuous systems

A control method is presented based on the use of piecewise continuous systems (PCS) as a control vector generator over sampling periods. The PCS has two inputs and one output which is equivalent to the control vector. Each input is corresponding to one specific time space, the first to the discrete time space defined by S = {tk, k = 0,1,2, … } and the second to the continuous time space t ∈ ℑ − S with ℑ = { t ∈ [0,∞ [ }. The control is generated in the time space ℑ. The architecture involving the PCS contains two feedback loops, based on the concept of double time and input spaces. These inputs are computed using two transformation maps Ψ and Φ defined in functions of the control strategy adopted to achieve the desired control properties. The control law depends on the PCS properties and on the method used to generate PCS controller inputs. Two examples are given: in the first the PCS controller is working in open-loop configuration during a sample period, therefore ripple is possible during sampling period. This limited control strategy assures imposed trajectory tracking only at sampling instants. In the second example the PCS is generating the control that satisfies the antiripple control strategy. The plant state is observed in continuous time and the imposed state trajectory must be compared with the plant state continuously. The PCS controller initial state is generated according to ‘optimal control’ law that minimises the quadratic criterion concerning the error-control compromise. This method appears to have several advantages over dynamic controllers: it provides control system designers with more freedom, and it requires an important computation only at the beginning of control process. Examples are given.

"AND" Logic Function of Molecular Photodiode Consisting of GFP/TCNQ Hetero-Film

Molecular logic gate device with "AND" logic function was developed. In this research, the "AND" function logic gate was fabricated with double line structured bio-photodiode consisted of GFP/TCNQ hetero-film. When a light was irradiated to a single (A or B) or double (A and B) line bio-photodiode as input, the steady state photocurrent was generated in part of "A+B" as output. The photocurrent intensity generated in single line input, was lower than that of double line input. The high photocurrent intensity indicates (1,1) in truth tables and low photocurrent intensity indicates (0,1) or (1,0). Finally, (0,0) input corresponds to a dark state without light generation. The "AND" gate function was successfully achieved based on high- and low-photocurrent.

"AND" Logic Function of Molecular Photodiode Consisting of GFP/TCNQ Hetero-Film

Molecular logic gate device with "AND" logic function was developed. In this research, the "AND" function logic gate was fabricated with double line structured bio-photodiode consisted of GFP/TCNQ hetero-film. When a light was irradiated to a single (A or B) or double (A and B) line bio-photodiode as input, the steady state photocurrent was generated in part of "A+B" as output. The photocurrent intensity generated in single line input, was lower than that of double line input. The high photocurrent intensity indicates (1,1) in truth tables and low photocurrent intensity indicates (0,1) or (1,0). Finally, (0,0) input corresponds to a dark state without light generation. The "AND" gate function was successfully achieved based on high- and low-photocurrent.

ESD-level circuit simulation impact of interconnect RC-delay on HBM and CDM behavior

An extraction method for the distributed, parasitic RC-elements of MOS single- and multi-fingers is introduced by deducing a rule of thumb for an effective poly resistance R eff. The lumped RC element described by the effective gate resistance in conjunction with the non-linear gate capacitance of the MOS model C gate approximates sufficiently accurate the distributed RC elements of the gate in the ESD relevant time domain. In addition to the wiring and parasitic capacitance connected to a gate, this RC can cause a significant gate delay (RC∼1 ns) during ESD events. It is demonstrated for a CMOS output driver circuit that this effect is relevant for ESD switching behavior under human body model (HBM) stress. Here, circuit simulations are compared to the corresponding transmission line pulse (TLP) measurements. Furthermore, a general charge device model (CDM)-level circuit simulation methodology is presented. To our knowledge for the first time, a single-pin CDM event was simulated in a complex I/O circuit applying appropriate ESD models suitable for CDM simulation. Under such stress, the simulation reveals an unexpected large impact of the ‘gate’ RC-delay formed by metal interconnects in a CMOS double input inverter. Voltage overshoots occur at internal gates and lead to oxide breakdown. The failure signature was validated by CDM stress tests and physical failure analysis.

Nonlinear viscoelastic effects in oscillatory shear deformation of brain tissue

Two nonlinear constitutive models were used to describe the dynamic viscoelastic behavior of brain tissue. Small disc-shaped samples of bovine brain tissue were tested in simple shear using forced vibrations (0.5 to 200 Hz) with finite amplitudes (up to 20% Lagrangian shear strain). The samples response to simple, double, and triple harmonic inputs was determined in order to characterize the nonlinearities up to the third-order. A quasilinear viscoelastic model was proposed to describe the spatial nonlinearity. A fully nonlinear viscoelastic model with product-form multiple hereditary integrals was proposed to describe the spatial as well as the temporal nonlinearities. The fully nonlinear model demonstrated superiority at high frequencies (above 44 Hz). Under finite strains, the linear complex modulus showed nonrecoverable asymptotic strain conditioning behavior. Discrepancies observed in previously published studies and the threshold of functional failure of the neural tissue were shown to be related to this strain conditioning effect.

Switched dynamical systems with double periodic inputs: an analysis tool and its application to the buck-boost converter

This paper considers a class of switched dynamical systems to which two periodic inputs are applicable. We derive a one-dimensional (1-D) return map and its derivative analytically for arbitrary shapes of the inputs. Based on the derivative, we introduce a slope chart that displays the relationship between the slope of the return map and that of the inputs. Applying the slope chart to a simplified model of the buck-boost converter (SBBC) with two periodic triangular inputs, we obtain a sufficient condition for chaos generation and that for the stability of the periodic behavior. The conditions guarantee that the first input can cause chaotic or periodic behavior and that the second input can change from chaotic behavior into periodic behavior and vice versa. A circuit model of the system is also proposed and the periodic and chaotic behaviors are demonstrated in the laboratory.

Inelastic dissipation in wobbling asteroids and comets

Asteroids and comets dissipate energy when they rotate about the axis different from the axis of the maximal moment of inertia. We show that the most efficient internal relaxation happens at the double frequency of body's tumbling. Therefore the earlier estimates that ignore double frequency input underestimate the internal relaxation in asteroids and comets. We show that the Earth seismological data may poorly represent acoustic properties of asteroids and comet as internal relaxation increases in the presence of moisture. At the same time owing to non-linearlity of inelastic relaxation small angle nutations can persist for very long time spans, but our ability to detect such precessions is limited by the resolution of the radar-generated images. Wobbling may provide valuable information on the composition and structure of asteroids and on their recent history of external impacts.

Mercury budget of an upland-peatland watershed

Inputs, outputs, and pool sizes of total mercury (Hg) were measured in a forested 10 ha,watershed consisting of a 7 ha hardwood-dominated upland surrounding a 3 ha coniferdominated peatland. Hydrologic inputs via throughfall and stemflow, 13 +/- 0.4/ug m-2 yr-1 over the entire watershed, were about double precipitation inputs in the open and were significantly higher in the peatland than in the upland (19.6 vs. 9.8/ug m-2 yr-1). Inputs of Hg via litterfall were 12.3 +/- 0.7/ug m-2 yr-1,/sup> , not different in the peatland and upland (11.7 vs. 12.5 ug m-2 yr-1). Hydrologic outputs via streamflowwere 2.8 +/- 0.3/ug m-2 yr-1 and the contribution from the peatland was higher despite its smaller area. The sum of Hg inputs were less than that in the overstory trees, 33+/-3 ug m-2 above-ground, and much less than either that in the upland soil, 5250+/-520ug m-2, or in the peat, 3900+/-100ug m-2 in the upper 50cm. The annual flux of Hg measured in streamflow and the calculated annual accumulation in the peatland are consistent with values reported by others. A sink for Hg of about 20ug m-2 yr-1 apparently exists in the upland, and could be due to either or both storage in the soil or volatilization.

Design of self-organising controller with dual outputs

A new fuzzy logic controller called a self-organising controller with dual outputs (SOCDO) is presented. The SOCDO has dual outputs in the basic level and updates its control rules as it monitors measures of performance. To implement the SOCDO, the authors regard an SISO process as a double input double output (DIDO) in the self-organising level. The advantage of the SOCDO is that it shows characteristics of PID even though it has only two inputs for the FLC, i.e. error and change of error, hence it yields both zero steady-state error and fast rising time.

Minimum-time reorientation of a two-degree-of-freedom gyroscope

The problem of time-optimal reorientation of the inner gimbal of a two-degree-of-freedom gimballed gyroscope mounted on a nonrotating base is considered. The states in the gyro model are the gimbals' angles (nutation is ignored). The model is nonlinear (not limited to small angles), state constrained, control limited, and double input, double output. A simple, explicit solution based on an intuitive observation is presented; it exploits the system's nonlinearity and channel coupling for attaining the minimum-tune goal. It is analytically shown, in detail, that the solution satisfies the Maximum Principle and fulfills a sufficient condition for optimality based on the Hamilton-Jacobi-Bellman equation.

A Double Weibull Input Function Describes the Complex Absorption of Sustained-Release Oral Sodium Valproate

The pharmacokinetics of valproic acid after oral administration of sustained-release formulations were studied in 12 healthy volunteers. The objective of the present study was to find an appropriate mathematical model to describe the complex drug intake process. The concentration of valproic acid in plasma was measured by HPLC. For each subject, during the input process a double peak phenomenon was observed, the plasma concentrations were fitted according to a single or a double Weibull input function, and then a first-order elimination rate was used to describe the observed data. The Weibull model was considered as an approximation of the overall process. The mean peak plasma concentration, 34.6 ± 8.9 mg/L, was reached after 8.6 ± 2.7 h. A single Weibull function adequately described the observed data for three subjects; the mean Weibull parameters were td (the time necessary to transfer 63% of the administered drug into the systemic circulation) of 7.87 ± 3.53 h and γ (shape) of 1.16 ± 0.66. A double Weibull input function was used for nine subjects; the mean Weibull parameters were td1= 2.35 ± 1.18 h and td2= 9.36 ± 4.47 h and γ2= 1.77 ± 2.27 and γ2= 3.68 ± 3.26. The mean half-life value of the elimination phase was 14.4 ± 4.6 h.

Aeration of Stratified Lakes: Theory and Practice

ABSTRACT Layer aeration (U.S. Pat. 4,724,086) can be described as a depth-discrete artificial circulation technique. Like destratification, it uses both photosynthetic and diffusional sources of oxygen to overcome oxygen demand. Like hypolimnetic aeration, it maintains necessary vertical temperature structure for coldwater fish and zooplankton refugia. Layer aeration alters thermal structure, creating several functional thermoclines, while retaining stratification stability. Persistent metalimnetic anoxia and increased eddy diffusional transport across the thermocline, common problems with hypolimnetic aeration, are overcome by layer aeration. A 7-year study was conducted to demonstrate aeration efficiency, ecosystem response, and water supply benefits from layer aeration of a 212 ha (523 acre), 21 m (70 ft) deep, eutrophic water supply lake using two 30 HP compressors. Aerator oxygen input was a function of influent dissolved oxygen (DO) and temperature. Oxygen input efficiencies ranged from 2% to 13% m−1. Redistribution of available DO during layer aeration essentially doubled oxygen input, reaching a maximum of over 99% efficiency compared to the oxygen content of compressed air. Specially designed air-water separators increased oxygen input of both hypolimnetic and layer aerators (by 1–2% m−1). The ecosystem response to layer aeration occurred in several annual stages. Overall summer Secchi disk transparency increased from <1.8 m (<6 ft) to >4.6 m (>15 ft) due to elimination of Cyanobacteria blooms. Descent of compensation depth into the hypolimnion contributed to restoration of 2.5 × 106 m3 (2000 acre-ft) salmonid habitat and an additional 1.6 × 106 m3 (1300 acre-ft) zooplankton refugia. Large-bodied Cladocera (Daphnia sp.) returned as a dominant zooplankton population in 1990. Deep nitrification increased, and the ecosystem respiratory quotient (ERQ) decreased from 1.51 to 1.14, indicating a shift in respiratory processes from anaerobic to aerobic. Water supply benefits included elimination of prechlorination, extended granulated activated carbon (GAC) bed longevity, avoidance of taste and odor episodes, and reduced treatment cost. Aeration system sizing, the ammonia anomaly, and ecosystem energetics are discussed relative to ecosystem responses to aeration.

Does practice with dictation improve language skills?

Evidence suggests that double model inputs that combine visual and auditory stimuli are more powerful than those involving visual or auditor stimuli alone. This study has experimented with dictation that integrates the stream of speech and its written representation in an attempt to determine if repeated practice in taking dictation improves the students' language skills. The findings of this study are discussed in the light of the effect and amount of instruction, the incubation hypothesis, and the fossilization hypothesis.

Matched queueing systems with a double input

In this paper, we study the matched queueing system with a double input, M o M/PH/1, where the two inputs are two independent Poisson processes, and the service time is of PH-distribution. The L.S. transforms and the expectations of the distributions of occupation time and virtual waiting time of the type-1 customer are derived. The probability that the server is working, the mean non-idle period, and the mean busy period are also derived. The related algorithms are given with numerical results.