Electrical microfluidic pressure gauge for elastomer microelectromechanical systems

We report on an electrical microfluidic pressure gauge. A polydimethylsiloxane microvalve closes at a characteristic applied pressure determined by the material's properties and the valve's dimensions. Hence, when the same pressure is applied to all valves of a heterogeneous valve array, some valves close while others remain open. The state of the array is combined with knowledge of the respective characteristic closing pressures of the individual valves to yield an estimate of the applied pressure. The state of each valve is obtained by electrical measurements, since the electrical resistance of the respective underlying fluid-filled channel increases by at least two orders of magnitude as the valve closes and its insulating elastomer material interrupts the electrical circuit. The overall system functions as a pressure gauge with electrical readout. This device would be a critical component in active pressure-regulation loops in future integrated microfluidic systems

Extremes of geometric variables with applications to branching processes

We obtain limit theorems for the row extrema of a triangular array of zero-modified geometric random variables. Some of this is used to obtain limit theorems for the maximum family size within a generation of a simple branching process with varying geometric offspring laws.Comment: 12 pages, some proofs are added to the published versio

Conformal Scalar Propagation on the Schwarzschild Black-Hole Geometry

The vacuum activity generated by the curvature of the Schwarzschild black-hole geometry close to the event horizon is studied for the case of a massless, conformal scalar field. The associated approximation to the unknown, exact propagator in the Hartle-Hawking vacuum state for small values of the radial coordinate above $r = 2M$ results in an analytic expression which manifestly features its dependence on the background space-time geometry. This approximation to the Hartle-Hawking scalar propagator on the Schwarzschild black-hole geometry is, for that matter, distinct from all other. It is shown that the stated approximation is valid for physical distances which range from the event horizon to values which are orders of magnitude above the scale within which quantum and backreaction effects are comparatively pronounced. An expression is obtained for the renormalised $$ in the Hartle-Hawking vacuum state which reproduces the established results on the event horizon and in that segment of the exterior geometry within which the approximation is valid. In contrast to previous results the stated expression has the superior feature of being entirely analytic. The effect of the manifold's causal structure to scalar propagation is also studied.Comment: 34 pages, 2 figures. Published on line on October 16, 2009 and due to appear in print in Gen.Rel.Gra

Impacts of the Administration's 2007 Farm Bill Proposal on Representative Crops, Dairy and Beef Cattle Farms -- Revised

For the first time in two decades, the Secretary of Agriculture provided the House and Senate Agriculture Committees a farm bill proposal from the Administration. The Administration’s Proposal is a comprehensive revision of the 2002 farm bill with suggested changes to all titles. Four major proposed changes to Title 1 Commodity Programs are analyzed and reported in this Briefing Paper. The four key policy changes analyzed are: - an increase in direct payment rates, - a reduction in loan rates for most crops, - the replacement of the counter cyclical payment (CCP) program with a counter cyclical revenue (CCR) program, and - a change in eligibility for farm program payments by using $200,000 adjusted gross income (AGI) for a means test. The economic impact of the Administration’s Proposal on the viability of 99 representative crop, dairy, and beef cattle farms is compared to a base situation of continuing the current farm bill through 2012. This report is a companion to FAPRI-UMC Report #11-07 that contains sector level impacts.Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Livestock Production/Industries,

The Farm Level Economic Impacts of Increased Cash Lease Rates

Higher commodity price expectations have led to increases in cash lease rates nationwide. This study evaluates the farm level impacts of higher cash lease rates. Current levels of cash rents along with land tenure arrangements of specific farms are instrumental in determining the impacts of increases in lease rates.Farm Management, Land Economics/Use,

Modelling and simulation of a Puma 560 manipulator for control system appraisal

The PUMA 560 Industrial Manipulator is presently controlled using a gain-scheduled PID control strategy. The implementation of adaptive control techniques can improve manipulator performance, [20]. One of the principal drawbacks with adaptive control is the difficulty in guaranteeing robustness over the complete operating range. This is particularly important when the plant is expensive and potentially self-damaging. An accurate, tuned, dynamic model, which includes the system’s main dynamics is a great asset to the control engineer. A complete model for the Puma 560 has not previously been developed. The research presented in this thesis derives a tuned and fully tested third order dynamic model for the first three links of the PUMA 560. A mathematical method of specifying the manipulator link structures and inter-relationships is discussed. By treating the manipulator as a connected chain of rigid bodies the Euler-Lagrange method is used to formulate second order dynamic equations and the servo-motor actuators and friction dynamics are incorporated into the model. The resulting third order model is simulated and tested in open and closed loop conditions. The model is then tuned, to provide a better representation of the actual manipulator dynamics, by comparing actual and simulated joint movements for the same actuator voltage input, PID control was implemented in software on each of the model joints independently. Simulated positional joint control resulted in sustained oscillations in joint positions indicating that simple constant gain PID controllers, without dynamic decoupling, were unable to produce satisfactory performance. The PUMA 560 controller board PID parameters were identified for two operating regions of joint 1. These values produced better dynamic performance when implemented in the simulated controller

Isolation of anti-toxin single domain antibodies from a semi-synthetic spiny dogfish shark display library

<p>Abstract</p> <p>Background</p> <p>Shark heavy chain antibody, also called new antigen receptor (NAR), consists of one single Variable domain (V_H), containing only two complementarity-determining regions (CDRs). The antigen binding affinity and specificity are mainly determined by these two CDRs. The good solubility, excellent thermal stability and complex sequence variation of small single domain antibodies (sdAbs) make them attractive alternatives to conventional antibodies. In this report, we construct and characterize a diversity enhanced semi-synthetic NAR V display library based on naturally occurring NAR V sequences.</p> <p>Results</p> <p>A semi-synthetic shark sdAb display library with a complexity close to 1e9 was constructed. This was achieved by introducing size and sequence variations in CDR3 using randomized CDR3 primers of three different lengths. Binders against three toxins, staphylococcal enterotoxin B (SEB), ricin, and botulinum toxin A (BoNT/A) complex toxoid, were isolated from panning the display library. Soluble sdAbs from selected binders were purified and evaluated using direct binding and thermal stability assays on the Luminex 100. In addition, sandwich assays using sdAb as the reporter element were developed to demonstrate their utility for future sensor applications.</p> <p>Conclusion</p> <p>We demonstrated the utility of a newly created hyper diversified shark NAR displayed library to serve as a source of thermal stable sdAbs against a variety of toxins.</p

AN INTERACTIVE ILLUSTRATION OF FARM PROGRAM PROVISIONS

Explaining the details and the impacts of government program provisions to agricultural producers can be a challenge for extension educators. This paper introduces a visual interactive tool that demonstrates the calculations of government payments established in the 2002 farm bill. Additionally, the paper explains how the tool is created in Microsoft® Excel and may be used in other areas.Agricultural and Food Policy,