Evolution of MPCV Service Module Propulsion and GNC Interface Requirements

The Orion Multi-Purpose Crew Vehicle Service Module Propulsion Subsystem provides propulsion for the integrated Crew and Service Module. Updates in the exploration architecture between Constellation and MPCV as well as NASA's partnership with the European Space Agency have resulted in design changes to the SM Propulsion Subsystem and updates to the Propulsion interface requirements with Guidance Navigation and Control. This paper focuses on the Propulsion and GNC interface requirement updates between the Constellation Service Module and the European Service Module and how the requirement updates were driven or supported by architecture updates and the desired use of hardware with heritage to United States and European spacecraft for the Exploration Missions, EM-1 and EM-2

Action at a distance as a full-value solution of Maxwell equations: basis and application of separated potential's method

The inadequacy of Li\'{e}nard-Wiechert potentials is demonstrated as one of the examples related to the inconsistency of the conventional classical electrodynamics. The insufficiency of the Faraday-Maxwell concept to describe the whole electromagnetic phenomena and the incompleteness of a set of solutions of Maxwell equations are discussed and mathematically proved. Reasons of the introduction of the so-called ``electrodynamics dualism concept" (simultaneous coexistence of instantaneous Newton long-range and Faraday-Maxwell short-range interactions) have been displayed. It is strictly shown that the new concept presents itself as the direct consequence of the complete set of Maxwell equations and makes it possible to consider classical electrodynamics as a self-consistent and complete theory, devoid of inward contradictions. In the framework of the new approach, all main concepts of classical electrodynamics are reconsidered. In particular, a limited class of motion is revealed when accelerated charges do not radiate electromagnetic field.Comment: ReVTeX file, 24pp. Small corrections which do not have influence results of the paper. Journal reference is adde

Dipolar origin of the gas-liquid coexistence of the hard-core 1:1 electrolyte model

We present a systematic study of the effect of the ion pairing on the gas-liquid phase transition of hard-core 1:1 electrolyte models. We study a class of dipolar dimer models that depend on a parameter R_c, the maximum separation between the ions that compose the dimer. This parameter can vary from sigma_{+/-} that corresponds to the tightly tethered dipolar dimer model, to R_c --> infinity, that corresponds to the Stillinger-Lovett description of the free ion system. The coexistence curve and critical point parameters are obtained as a function of R_c by grand canonical Monte Carlo techniques. Our results show that this dependence is smooth but non-monotonic and converges asymptotically towards the free ion case for relatively small values of R_c. This fact allows us to describe the gas-liquid transition in the free ion model as a transition between two dimerized fluid phases. The role of the unpaired ions can be considered as a perturbation of this picture.Comment: 16 pages, 13 figures, submitted to Physical Review

Kinematics and hydrodynamics of spinning particles

In the first part (Sections 1 and 2) of this paper --starting from the Pauli current, in the ordinary tensorial language-- we obtain the decomposition of the non-relativistic field velocity into two orthogonal parts: (i) the "classical part, that is, the 3-velocity w = p/m OF the center-of-mass (CM), and (ii) the so-called "quantum" part, that is, the 3-velocity V of the motion IN the CM frame (namely, the internal "spin motion" or zitterbewegung). By inserting such a complete, composite expression of the velocity into the kinetic energy term of the non-relativistic classical (i.e., newtonian) lagrangian, we straightforwardly get the appearance of the so-called "quantum potential" associated, as it is known, with the Madelung fluid. This result carries further evidence that the quantum behaviour of micro-systems can be adirect consequence of the fundamental existence of spin. In the second part (Sections 3 and 4), we fix our attention on the total 3-velocity v = w + V, it being now necessary to pass to relativistic (classical) physics; and we show that the proper time entering the definition of the four-velocity v^mu for spinning particles has to be the proper time tau of the CM frame. Inserting the correct Lorentz factor into the definition of v^mu leads to completely new kinematical properties for v_mu v^mu. The important constraint p_mu v^mu = m, identically true for scalar particles, but just assumed a priori in all previous spinning particle theories, is herein derived in a self-consistent way.Comment: LaTeX file; needs kapproc.st

TGF-β1 Down-Regulation of NKG2D/DAP10 and 2B4/SAP Expression on Human NK Cells Contributes to HBV Persistence

The mechanism underlying persistent hepatitis B virus (HBV) infection remains unclear. We investigated the role of innate immune responses to persistent HBV infection in 154 HBV-infected patients and 95 healthy controls. The expression of NKG2D- and 2B4-activating receptors on NK cells was significantly decreased, and moreover, the expression of DAP10 and SAP, the intracellular adaptor proteins of NKG2D and 2B4 (respectively), were lower, which then impaired NK cell-mediated cytotoxic capacity and interferon-γ production. Higher concentrations of transforming growth factor-beta 1 (TGF-β1) were found in sera from persistently infected HBV patients. TGF-β1 down-regulated the expression of NKG2D and 2B4 on NK cells in our in vitro study, leading to an impairment of their effector functions. Anti-TGF-β1 antibodies could restore the expression of NKG2D and 2B4 on NK cells in vitro. Furthermore, TGF-β1 induced cell-cycle arrest in NK cells by up-regulating the expression of p15 and p21 in NK cells from immunotolerant (IT) patients. We conclude that TGF-β1 may reduce the expression of NKG2D/DAP10 and 2B4/SAP, and those IT patients who are deficient in these double-activating signals have impaired NK cell function, which is correlated with persistent HBV infection

Laboratory tests of composite wood-concrete beams

Exploratory research related to the effectiveness of layered composite solid wood-concrete floor systems is described. Rectangular beams comprised of a concrete layer atop a solid dimension lumber layer were load tested. Interlayer force transfer is accomplished by bearing in a notched shear key. A vertical anchor is utilized to restore tightness of the notch after the concrete cures. Test results indicated the structural merit of the concept based on the degree of partial composite action achieved. (C) 2007 Elsevier Ltd. All rights reserved

Investigation of notched composite wood-concrete connections

An initial stage of research on the feasibility of a composite concrete-wood commercial floors system is described. The floors are comprised of concrete placed atop a solid layer of dimension lumber. A notched shear key/anchor detail is used for interlayer connection. This connection detail transfers interlayer force by bearing adjacent materials in the notch. The anchor serves to tighten the layers after curing of the concrete. Initial testing included pull-out tests on the anchor and interlayer slip tests to define the geometry of the connection detail. Test results indicated the structural merit of the connection concept compared to the use of ordinary mechanical connectors

Transport of digesta in the human and porcine small intestinal mucus

Small intestinal mucus has evolved to provide a robust barrier that can trap and immobilise potentially hazardous particulates such as bacteria and yet still allow the passage of nutrients to the epithelium. However, the rules governing this selective barrier function remain largely unknown, and scientific studies rely usually on animal mucus samples to explain this part of human physiology.In our study we used quantitative confocal microscopy to look at the transport characteristics in porcine ex vivo intestinal mucus of post-digestion lipid droplets that derived from in vitro digestion of yogurt. We also used a multiple-particle tracking technique to investigate the permeability of the mucus to model, sub-micron size particles. This was done in order to compare the microrheology of the mucus between different locations in the small intestine (e.g. proximal jejunum vs. distal ileum).Most importantly, we used the above experimental approaches to investigate the permeability of human ex vivo small intestinal mucus that was obtained from a number of healthy subjects. This type of human material is not easily available for research purposes. Therefore the major aim of our study was to compare the diffusion of particulates in human mucus with diffusion in porcine mucus. Our results shed light on whether the readily available porcine mucus is a reliable substitute for studying the microstructure and permeability of the mucus layer in the human small intestine. This will potentially contribute to simulating, in a more physiologically-relevant fashion, not only the digestion processes, but also the transport and absorption mechanisms in the gut. Such insights will help support efforts to both engineer fabricated foods with enhanced nutritional quality required to fight various diet-related health problems, and to overcome the failure of many pharmaceutical and nutraceutical preparations to provide effective oral delivery of active compounds