This study investigated the crop density in a New Holland BB960 (branch of CNH Global N.V.) large square baler as examined by crop trajectory from the precompression room to the bale chamber. This study also examined both the top and bottom plunger pressures and critical factors affecting the final top and bottom bale densities.<p>The crop trajectories (wad of crop) were measured using a high-speed camera from the side of the baler through viewing windows. The viewing windows were divided into four regions for determining the crop displacement, velocity and acceleration. Crop strain was used to evaluate the potential change in density of the crop before being compressed by the plunger. Generally, the vertical crop strain was found to be higher in the top half of the bale compared to the bottom. <p>Average strain values for side measurements were 12.8% for the top and 2.1% for the bottom. Plunger pressures were measured to compare peak pressures between the top and bottom halves of each compressed wad of crop, and to develop pressure profiles based on the plungers position. Results of comparing the mean peak plunger pressures between the top and bottom locations indicated the mean pressures were significantly higher at the top location with the exception of one particular setting. Resulting pressure profile graphs aided in qualitatively describing the compression process for both top and bottom locations.<p>A stepwise regression model was developed to examine the difference in material quantity in the top half of the bale compared to the bottom, based on bale weights. The model indicated that flake setting, stuffer ratio and number of flakes had the greatest effect on maintaining consistent bale density by comparing top to bottom halves of each bale. The R2 (coefficient of determination) value for the developed model was of 59.9%. The R2 was low although could be accounted for due to the limited number of data points in the developed model.

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This study investigated the crop density in a New Holland BB960 (branch of CNH Global N.V.) large square baler as examined by crop trajectory from the precompression room to the bale chamber. This study also examined both the top and bottom plunger pressures and critical factors affecting the final top and bottom bale densities.<p>The crop trajectories (wad of crop) were measured using a high-speed camera from the side of the baler through viewing windows. The viewing windows were divided into four regions for determining the crop displacement, velocity and acceleration. Crop strain was used to evaluate the potential change in density of the crop before being compressed by the plunger. Generally, the vertical crop strain was found to be higher in the top half of the bale compared to the bottom. <p>Average strain values for side measurements were 12.8% for the top and 2.1% for the bottom. Plunger pressures were measured to compare peak pressures between the top and bottom halves of each compressed wad of crop, and to develop pressure profiles based on the plungers position. Results of comparing the mean peak plunger pressures between the top and bottom locations indicated the mean pressures were significantly higher at the top location with the exception of one particular setting. Resulting pressure profile graphs aided in qualitatively describing the compression process for both top and bottom locations.<p>A stepwise regression model was developed to examine the difference in material quantity in the top half of the bale compared to the bottom, based on bale weights. The model indicated that flake setting, stuffer ratio and number of flakes had the greatest effect on maintaining consistent bale density by comparing top to bottom halves of each bale. The R2 (coefficient of determination) value for the developed model was of 59.9%. The R2 was low although could be accounted for due to the limited number of data points in the developed model.

In order to extend fluid-based flow control techniques that have been demonstrated at low subsonic speeds to high speed flows, it is necessary to develop actuators having sufficient momentum to control and manipulate high speed flows. Two fluidic actuation approaches are developed where the control jet may reach supersonic velocities and their performance is characterized. The first actuator is a compressible synthetic (zero net mass flux) jet. This is an extension of previous work on synthetic jets with an increase in driver power yielding substantial pressurization of the cavity such that the flow is compressible. The jet is generated using a piston/cylinder actuator, and the effects of variation of the orifice diameter, actuation frequency, and compression ratio are investigated. Operation in the compressible regime uniquely affects the time-dependent cylinder pressure in that the duty cycle of the system shifts such that the suction phase is longer than the blowing phase. The structure of the jet in the near-field is documented using particle image velocimetry and Schlieren flow visualization. In the range investigated, the stroke length is sufficiently long that the jet flow is dominated by a starting jet rather than a starting vortex (which is typical of low-speed synthetic jets). A simple, quasi-static numerical model of the cylinder pressure is developed and is in generally good agreement with the experimental results. This model is used to assess system parameters which could not be measured directly (e.g., the dynamic gas temperature and mass within the cylinder) and for predictions of the actuator performance beyond the current experimental range. Finally, an experiment is described with self-actuated valves mounted into the cylinder head which effectively icrease the orifice area in suction and overcome some of the limitations inherent to compressible operation. The second actuation concept is the combustion-driven jet actuator. This device consists of a small-scale (nominally 1 cc) combustion chamber which is filled with premixed fuel and oxidizer. The mixture is ignited using an integrated spark gap, creating a momentary high pressure burst within the combustor that drives a high-speed jet from an exhaust orifice. At these scales, the entire combustion process is complete within several milliseconds and the cycle resumes when fresh fuel/oxidizer is fed into the chamber and displaces the remaining combustion products. The actuator performance is characterized by using dynamaic measurements of the combustor pressure along with Schlieren flow visualization, limited dynamic thrust measurements, and flame photography. The effects of variation in the following system parameters are investigated: fuel type and mixture ratio, exhaust orifice diameter, chamber aspect ratio, chamber volume, fuel/air flow rate, ignition/combustion frequency, and spark ignition energy. The resulting performance trends are documented and the basis for each discussed. Finally, a proof-of-concept experiment demonstrates the utility of teh combustion-driven jet actuators at low-speed for transitory reattachment of a separated flow over an airfoil at high angles of attack.

We propose two kinds of 1.0 Gbps LVDS ( low voltage differential signaling ) transceivers for LCD ( liquid crystal display ) in this thesis. LVDS has become a popular choice for high-speed serial links in large-sized display units. Our designs are an I/O interface circuit for Gbps operation which is fully complied with the IEEE STD 1596.3 (LVDS). A step-down voltage regulator is employed to reject the noise coupled in the system power supply. In the first design of the transmitter, a CMFB (common mode feedback) circuitry is utilized to stabilize the common voltage in a pre-defined range. In the second design of the transmitter, we try to use a DC bias circuitry to stabilize output common mode voltage to further improve the stability of the common mode voltage. By contrast, a regenerative circuit which provides a positive feedback loop gain between the preamplifier and the output buffer in the receiver such that the received bit streams can be correctly restored

Abstract In this thesis, we propose a new geometrical structure of waveguide for the application of traveling-wave electroabsorption modulator (TWEAM). As approaching to high-speed performance in TWEAM, low parasitic capacitance in the waveguide is necessary to get good microwave propagation properties. In this work, a novel processing called two-step undercut-etching the active region (UEAR) is developed to reduce the parasitic capacitance. First of all, Beam Propagation Method (BPM) is used to calculate this 2-D structure optical modes ensuring the guiding capability in such kind of waveguides. Based on an equivalent circuit model, the microwave propagation on different structures of waveguide is then investigated to decide the UEAR waveguide structure. By the selectively etching solution on InP/InGaAsP, the processing by two-step UEAR is developed to reduce the parasitic capacitance in the waveguide core. H3PO4:HCl is used to selectively etch P-InP layer on the top of InGaAsP M.Q.W. (multiple quantum wells, active region). H3PO4:H2O2:H2O is subsequently and selectively remove InGaAsP M.Q.W.s to define the waveguide core. This processing has been successfully developed. The electrical transmission measurement on this kind of TWEAM shows low reflection S11 of < -17.5dB and a low insertion loss S21 of < ¡V2.7dB from D.C. to 40GHz, indicating high microwave performance on such two-step UEAR waveguide can be achieved due to the low parasitic capacitance.

This dissertation proposed two time-domain algorithms for extracting the broadband SPICE-compatible models of high-speed coupled interconnects. The first approach is proposed to synthesized the equivalent models of multi-conductor interconnects by cascading multiple configuration-oriented coupled transmission line (CCTL) units. The second approach focuses on the modeling of differential via based on a broadband macro-£k model with three modules represented by the optimum pole-residue forms. Using a systematic lumped-model extraction technique (SLET), all the pole-residue rational functions can transfer into a corresponding lumped model. The accuracy of the two algorithms is demonstrated both in time- and frequency -domain responses comparison with the direct 3D-FDTD simulation.

The problem of dilemma zone protection and red-light-running is especially important in certain rural intersections due to the higher speeds at these intersections and their isolated nature. In addition, the presence of a larger percentage of trucks mean that adequate warning and help need to be given to these truck drivers in order to enable them to stop safely, or proceed through the intersection before the onset of red. To curb any potential danger at such intersections, a Texas Department of Transportation (TxDOT) research project on Advanced Warning for End of Green Phase (AWEGS) at high speed intersections deployed AWEGS at two rural intersection sites ?? Tx 6 @ FM 185 near Waco and US 290 @ FM 577 in Brenham. The deployment of AWEGS involved a Level 1 and a later upgrade to a more efficient Level 2 in Waco. Initial results on red-light-running, even though promising, were expressed as observed red-light-running events per day. These resulting rates did not reflect exposure, and the results also raised some concerns with regards to some increase in red-light-running from Level 1 to Level 2. A more detailed analysis of the red-light-running issue at these two sites is provided in this thesis. The main areas of red-light-running analyses presented here are with respect to the reductions in red-light-running rates for the exposure factors of number of cycles and vehicular volumes, the comparison of day and night RLR rates and the nature of speeds of vehicles running the red light at the intersection in Waco. AWEGS was found to reduce the total red-light-running per exposure factor after its deployment. Both Level 1 and Level 2 AWEGS operations were found to reduce red-light-running by up to 60%. Generally, total red-light-running per exposure factor between Level 1 and Level 2 was found to be about the same. Level 2 had lower daytime red-light-running rates and higher nighttime rates than Level 1. Generally, day rates were found to be higher than night rates for all levels of AWEGS deployment. It is recommended that, to better understand the operational aspects of AWEGS and to improve its operations, more implementation of AWEGS and further tests be done. An automated method to collect and analyze data needs to be developed as well as a means of automatically recording video data for calibration and verification It is also recommended that Level 1 technology be implemented in areas where the Level 2 technology may be either too complex or too expensive.

This dissertation proposed a novel time-domain algorithm for extracting the broadband SPICE-compatible models of power/ground planes with resonance effect. The time-domain algorithm approach can focus on the modeling of interconnectors and power/ground planes based on a broadband macro model. Every module of the broadband macro model is represented by the optimum pole-residue forms. Using a systematic lumped-model extraction technique, all the optimum pole-residue rational functions can be transferred into a corresponding lumped circuit model. The accuracy of the time-domain algorithms is demonstrated both in time- and frequency-domain responses comparison by the 3D-FDTD simulation and measurement. In addition, these models can be efficiently incorporated into the currently available circuit simulator such as HSpice for the consideration of power/ground bouncing noise with active devices in high-speed circuits.

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