Method of Testing Oxygen Regulators

Oxygen regulators are used in aircraft to regulate automatically the flow of oxygen to the pilot from a cylinder at pressures ranging up to 150 atmospheres. The instruments are adjusted to open at an altitude of about 15,000 ft. and thereafter to deliver oxygen at a rate which increases with the altitude. The instruments are tested to determine the rate of flow of oxygen delivered at various altitudes and to detect any mechanical defects which may exist. A method of testing oxygen regulators was desired in which the rate of flow could be determined more accurately than by the test method previously used (reference 1) and by which instruments defective mechanically could be detected. The new method of test fulfills these requirements

Complete Genome Sequence of a Divergent Human Rhinovirus C Isolate from an Infant with Severe Community-Acquired Pneumonia in Colorado, USA.

Here, we report the genome sequence of a divergent human rhinovirus C isolate identified from an infant with a severe community-acquired respiratory infection. RNA sequencing performed on an Illumina platform identified reads aligning to human rhinovirus species, which were de novo assembled to produce a coding-complete genome sequence

Input-to-state stability of infinite-dimensional control systems

We develop tools for investigation of input-to-state stability (ISS) of infinite-dimensional control systems. We show that for certain classes of admissible inputs the existence of an ISS-Lyapunov function implies the input-to-state stability of a system. Then for the case of systems described by abstract equations in Banach spaces we develop two methods of construction of local and global ISS-Lyapunov functions. We prove a linearization principle that allows a construction of a local ISS-Lyapunov function for a system which linear approximation is ISS. In order to study interconnections of nonlinear infinite-dimensional systems, we generalize the small-gain theorem to the case of infinite-dimensional systems and provide a way to construct an ISS-Lyapunov function for an entire interconnection, if ISS-Lyapunov functions for subsystems are known and the small-gain condition is satisfied. We illustrate the theory on examples of linear and semilinear reaction-diffusion equations.Comment: 33 page

Optimal controller gain tuning for robust stability of spacecraft formation

The spacecraft formation control problem sets high demands to the performance, especially with respect to positional accuracy. The problem is further complicated due to scarce fuel resources and limited actuation effects, in addition to the many sources of disturbances. This paper addresses the problem of finding the optimal gains of spacecraft formation controllers. By optimal, we mean the gains that minimizes a cost functional which penalizes both the control efforts and the state deviation, while still guaranteeing stability of the closed-loop systems in the presence of disturbances

An ISS Small-Gain Theorem for General Networks

We provide a generalized version of the nonlinear small-gain theorem for the case of more than two coupled input-to-state stable (ISS) systems. For this result the interconnection gains are described in a nonlinear gain matrix and the small-gain condition requires bounds on the image of this gain matrix. The condition may be interpreted as a nonlinear generalization of the requirement that the spectral radius of the gain matrix is less than one. We give some interpretations of the condition in special cases covering two subsystems, linear gains, linear systems and an associated artificial dynamical system.Comment: 26 pages, 3 figures, submitted to Mathematics of Control, Signals, and Systems (MCSS

Singularly Perturbed Monotone Systems and an Application to Double Phosphorylation Cycles

The theory of monotone dynamical systems has been found very useful in the modeling of some gene, protein, and signaling networks. In monotone systems, every net feedback loop is positive. On the other hand, negative feedback loops are important features of many systems, since they are required for adaptation and precision. This paper shows that, provided that these negative loops act at a comparatively fast time scale, the main dynamical property of (strongly) monotone systems, convergence to steady states, is still valid. An application is worked out to a double-phosphorylation ``futile cycle'' motif which plays a central role in eukaryotic cell signaling.Comment: 21 pages, 3 figures, corrected typos, references remove

Solving Einstein's Equations With Dual Coordinate Frames

A method is introduced for solving Einstein's equations using two distinct coordinate systems. The coordinate basis vectors associated with one system are used to project out components of the metric and other fields, in analogy with the way fields are projected onto an orthonormal tetrad basis. These field components are then determined as functions of a second independent coordinate system. The transformation to the second coordinate system can be thought of as a mapping from the original ``inertial'' coordinate system to the computational domain. This dual-coordinate method is used to perform stable numerical evolutions of a black-hole spacetime using the generalized harmonic form of Einstein's equations in coordinates that rotate with respect to the inertial frame at infinity; such evolutions are found to be generically unstable using a single rotating coordinate frame. The dual-coordinate method is also used here to evolve binary black-hole spacetimes for several orbits. The great flexibility of this method allows comoving coordinates to be adjusted with a feedback control system that keeps the excision boundaries of the holes within their respective apparent horizons.Comment: Updated to agree with published versio

A new genus of predatory midge in the \u3ci\u3eMonohelea\u3c/i\u3e complex from Eocene Baltic amber (Diptera: Ceratopogonidae)

Monogedania, a new fossil monotypic genus of predatory midge (Diptera: Ceratopogonidae) is described from Eocene Baltic amber and its position within the Monohelea complex is discussed. We dis­covered that the membranous portion of the aedeagus is extended in Monogedania clunipes (Loew), new combination, which suggests that the aedeagus of some extinct predatory midges can be penis-like. The Eocene Monohelea baltica Szadziewski, is transferred to the genus Schizohelea Kieffer, new combination, and, the previously unknown female is described, and key characters are included in color photographs of its entire habitus, head, distal hind tarsomeres and claws. The Monohelea complex is a world-wide group of predatory midges that includes six genera in the tribe Cerato­pogonini (Wirth and Grogan 1988). Their larvae are aquatic or semiaquatic in mainly small bodies of water and prey on aquatic larvae of a variety of insects. Adult females in this tribe are predators of mostly small nematocer­ous flies. This complex includes 232 extant species (Borkent and Dominiak 2020). Biting midges of this complex are rare in ambers worldwide (Szadziewski 2018). There are only two named species in the genus Monohelea Kieffer from Eocene Baltic amber (Szadziewski 1988). However, an enigmatic specimen of the genus Austrohelea Wirth and Grogan (sex unknown, no description or illustration) was reported by Schmidt et al. (2018) from Oligocene/Miocene amber of New Zealand; and a species from Eocene Australian (Anglesea) amber of an unde­termined genus (Peñalver et al. 2021) may belong to this complex. It is worth noting that in Upper Cretaceous Canadian and Siberian ambers there are species in the fossil genus Peronehelea Borkent (Borkent 1995), that resemble species in the Monohelea complex. Females of Peronehelea have enlarged hind legs and hind claws, how­ever, males in this genus have abdominal tergite 9 with distinct apicolateral processes which are absent or greatly reduced in males of the Monohelea complex. Females of Peronehelea have enlarged hind legs and hind claws, however, males in this genus have abdominal tergite 9 with distinct apicolateral processes which are absent or greatly reduced in males of the Monohelea complex (Szadziewski 1996). Two species from Eocene Baltic amber assigned to Monohelea by Szadziewski (1988) do not entirely resemble any of the genera in the revised Monohelea complex proposed by Wirth and Grogan (1988). Herein, we transfer these two extinct species from Monohelea, to Schizohelea Kieffer (Kieffer 1917), and, the new genus Monogedania, that we describe and illustrate

The 4-H girl learns to can food and store : preservation I

University of Missouri College of Agriculture and the United States Department of Agriculture Cooperating--Page 24."May, 1943."Title from cover