A hybrid formulation for the probe-to-patch attachment-mode currentfor rectangular microstrip antennas

We present a hybrid representation for the attachment-mode current existing on the surface of a coaxially fed rectangular microstrip patch antenna. The hybrid representation consists of a one- or two-term residue and an eigenfunction series which gives the attachment-mode current at all points on the patch surface, including the probe-to-patch junction. It is numerically demonstrated that the residue and eigenfunction series blend smoothly in the close vicinity of the Stokes region which includes the probe-to-patch junction. The Stokes region is a very narrow region over which the attachment-mode current changes rapidly. The residue and eigenfunction series are used outside and within this Stokes region, respectively. This hybrid representation can be used in either spectral- or space-domain techniques for a full-wave solution to the microstrip antenna problem. The residue series is obtained by using an equivalent contour integral representation of the infinite eigenfunction series, which subsequently reduces to the Watson transform under the assumption of a slightly lossy substrate. At or near the Stokes regions the residue series is inadequate, as it cannot model the rapidly varying junction currents there. Examination of the residue series shows that the attachment mode is a superposition of exponentially attenuated, leaky, surface-traveling modes. This hybrid representation is expected to provide the optimum trade-off between speed and accuracy for computations involving electrically large finite arrays     

An automated, parallel processing approach to biomolecular sample preparation

Sample preparation for DNA and RNA assays is a prime candidate for laboratory automation. A novel, parallel processing device that performs the three separate liquid-handling functions necessary for such sample preparation-dispensing, pipetting, and pressurizing-is presented. The device comprises an array of fine nozzles connected by fluidic channels to automatically and precisely distribute flow between one source and an array of points. The design principles, as well as the experimental and computational methods used to develop the device, are described. Test results, including accuracy, uniformity, volume range, and timing, are presented. The functionality of the device is demonstrated by performing a solid-phase extraction of DNA with two types of microcolumns.     

Conventional and Unconventional Mechanisms by which Exocytosis Proteins Oversee β-cell Function and Protection

Type 2 diabetes (T2D) is one of the prominent causes of morbidity and mortality in the United States and beyond, reaching global pandemic proportions. One hallmark of T2D is dysfunctional glucose-stimulated insulin secretion from the pancreatic β-cell. Insulin is secreted via the recruitment of insulin secretory granules to the plasma membrane, where the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) and SNARE regulators work together to dock the secretory granules and release insulin into the circulation. SNARE proteins and their regulators include the Syntaxins, SNAPs, Sec1/Munc18, VAMPs, and double C2-domain proteins. Recent studies using genomics, proteomics, and biochemical approaches have linked deficiencies of exocytosis proteins with the onset and progression of T2D. Promising results are also emerging wherein restoration or enhancement of certain exocytosis proteins to β-cells improves whole-body glucose homeostasis, enhances β-cell function, and surprisingly, protection of β-cell mass. Intriguingly, overexpression and knockout studies have revealed novel functions of certain exocytosis proteins, like Syntaxin 4, suggesting that exocytosis proteins can impact a variety of pathways, including inflammatory signaling and aging. In this review, we present the conventional and unconventional functions of β-cell exocytosis proteins in normal physiology and T2D and describe how these insights might improve clinical care for T2D.     

The inhibitive effect of extraneous ion addition on stress corrosion cracking of alpha-brass

The addition of ammonium chloride, cobalt sulphate, cesium sulphate and ethylene diamine to a Mattsson solution and the addition of ammonium sulphate to the Pugh solution have been found to produce an inhibitive effect on the stress corrosion cracking of alpha-brass in these solutions. Ammonium chloride and ammonium sulphate additions affect the tarnish formation on the specimen as well as the cracking pattern. Electrochemical polarization studies have also been carried out with these two additives. The observations have been explained in the light of adsorption of these ionic species at selected sites on the metal surface and their possible interference with the cathodic reactions.     

Mass transfer from a carbon dioxide jet to tap water

When a jet of soluble gas is directed on to liquid surface, the kinetic energy of the jet is transferred to the liquid giving rise to circulation, which in turn enhances mass transfer. Consequently, the mass transfer coefficient is related to the characteristics of the jet.     

Polynomial-Time Algorithms for Energy Games with Special Weight Structures

Energy games belong to a class of turn-based two-player infinite-duration games played on a weighted directed graph. It is one of the rare and intriguing combinatorial problems that lie in NP∩co-NP, but are not known to be in P. The existence of polynomial-time algorithms has been a major open problem for decades and apart from pseudopolynomial algorithms there is no algorithm that solves any non-trivial subclass in polynomial time. In this paper, we give several results based on the weight structures of the graph. First, we identify a notion of penalty and present a polynomial-time algorithm when the penalty is large. Our algorithm is the first polynomial-time algorithm on a large class of weighted graphs. It includes several worst-case instances on which previous algorithms, such as value iteration and random facet algorithms, require at least sub-exponential time. Our main technique is developing the first non-trivial approximation algorithm and showing how to convert it to an exact algorithm. Moreover, we show that in a practical case in verification where weights are clustered around a constant number of values, the energy game problem can be solved in polynomial time. We also show that the problem is still as hard as in general when the clique-width is bounded or the graph is strongly ergodic, suggesting that restricting the graph structure does not necessarily help.     

Synthesizing robust systems

Systems should not only be correct but also robust in the sense that they behave reasonably in unexpected situations. This article addresses synthesis of robust reactive systems from temporal specifications. Existing methods allow arbitrary behavior if assumptions in the specification are violated. To overcome this, we define two robustness notions, combine them, and show how to enforce them in synthesis. The first notion applies to safety properties: If safety assumptions are violated temporarily, we require that the system recovers to normal operation with as few errors as possible. The second notion requires that, if liveness assumptions are violated, as many guarantees as possible should be fulfilled nevertheless. We present a synthesis procedure achieving this for the important class of GR(1) specifications, and establish complexity bounds. We also present an implementation of a special case of robustness, and show experimental results.     

NH3-NO/NO2 SCR for diesel exhausts after treatment: mechanism and modelling of a catalytic converter

We review herein the key mechanistic and kinetic features of the reactions involved in the NH₃-NO/NO₂ SCR system investigated by dynamic reactive experiments over a V-based commercial powdered catalyst, eventually leading to the proposal of an original redox scheme which accounts for stoichiometry, selectivity and intrinsic kinetics of the global SCR process.