Time Response Simulation of the 1975 Viking Orbiter Digital Tape Recorder

International Telemetering Conference Proceedings / October 15-17, 1974 / International Hotel, Los Angeles, CaliforniaThe objective of this study is to verify and understand in depth the performance of the speed control (frequency loop) servo of the 1975 Viking Orbiter (VO75) digital tape recorder (DTR). The linear frequency-domain methods, such as the Bode Plot and the Root Locus, are inadequate in analyzing the VO75 DTR servo due to such dominant non-linear effects as servo signal limiting and static/dynamic Coulomb friction. The Time Response method employed in this study is written in the Continuous System Simulation Language (CSSL) for the Univac 1108 computer system. In order to demonstrate the power and flexibility of the graphic interactive simulation program, four aspects of system dynamics are interactively adjusted to arrive at a number of stable system configurations which has significantly different tape transport and/or summing amplifier gain, larger static/dynamic Coulomb friction, system lag than envisioned in the nominal design by linear methods.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Influence of serum proteins on the kinetics of attachment of vero cells to cytodex microcarriers

The attachment characteristics of the Vero cell line on microcarriers has been found to be influenced by the serum proteins. Significant quantities of serum proteins were found to be adsorbed on the carrier surface, which resulted in decreased exchange capacity and a lower attachment rate constant. The kinetics of attachment followed primarily first order with respect to the concentration of free cells. With positively charged microcarriers the attachment process exhibited two distinct phases, an initial phase of normal attachment followed by a second phase characterized by a lower rate of attachment. The attachment rate constant in the first phase (0.062 min−1) was reduced to 0.01 min−1 in the second phase. Presumably, at a low concentration of free Vero cells, the attachment process is retarded by unadsorbed Bovine Serum Albumin (BSA) and other serum proteins present in the medium

Bioenergetic consequences in the interaction of mammalian cell and virus for the multiplication of recombinant vaccinia and expression of heterologous protein (β-hCG)

Energy generation in vaccinia virus infected Vero cell is investigated. The specific ATP pool in infected cells increases in the range of 40-80%, in contrast to uninfected cells. Virus replication and β-hCG expression are associated with the drop in ATP/ADP ratio from 7.0 to 2.5. High initial infection level leads to more energy generation and also more product formation

Time Response Simulation of the Guidance and Control System of an Automatically Steered Wire-Following Vehicle

International Telemetering Conference Proceedings / November 19-21, 1979 / Town and Country Hotel, San Diego, CaliforniaThe purpose of the multi-mode evasive vehicle, as defined by the U.S. Army Armored Vehicle Command, is to provide an automatically steered moving platform for a target silhouette which will be used for tank gunnery evaluation. The vehicle, as well as its guidance and control systems, must be rugged enough to withstand battle conditions, rough terrain, hostile weather conditions, and the impact of dummy shells on its superstructure. The vehicle's steering and speed control are accomplished remotely by signals sent via a guide wire laid on the ground. The Army Wire-Following-Vehicle (WFV) represents new technology in the area of automatic vehicle guidance and has a host of potential applications, both military (such as a target drone) and civilian (such as underground mining and rescue as well as surface mass transit on electronic guide ways). For an high-order non-linear system, such as the WFV with its guidance and speed control subsystems, the final design must be generated and verified by non-linear time-response simulation. This paper describes the time-response simulation studies undertaken by the authors in support of the development and validation of the guidance/steering subsystem of the WFV (including the vehicular motion on some sample guided courses). Such simulation is the cheapest and quickest way to determine the design tolerances and hence, the field worthiness of the WFV. The WFV guidance system hardware design based on the continuous time-response simulation reported in this study has resulted in successful accomplishment of desired performance goals.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Cellular affinity is the only deciding factor for microcarrier selection for the cultivation of anchorage dependent cells

Vero and BHK-21 cells are not attached and spreaded equally on the same microcarrier. BHK-21 cells require a microenvironment similar to the mammalian tissue for attachment and spreading. Cellular affinity, which control adhesion to the surface, varied with the growth phase, membrane integrity and the type of microcarrier

Physiological factors of growth and susceptibility to virus regulating Vero cells for optimum yield of vaccinia and cloned gene product (β-hCG)

Replication of vaccinia virus carrying β-hCG gene at the 'tk' locus was studied in microcarrier culture of Vero cell. The yields of recombinant vaccinia virus and its expressed product (β-hCG) were influenced by the physiological state of the host cell, at which it was infected. Cells infected with the virus between the 3rd and 6th day gave maximum amount of virus and β-hCG in a parallel manner, the yields of which were 2.3×10<SUP>9</SUP> pfu per 10<SUP>6</SUP> cells and 450 ng per 10<SUP>6</SUP> cells, respectively. The yields were reduced by 33-36% in the virus-infected stationary culture of the 8th day. The physiological state of the host cell has been quantified by the cellular activity parameter 'P' (μ(t)/μ<SUB>max</SUB>) in the scale of 1 to 0. The value of 'P' was highest in the exponentially growing culture, which reduced with decline in growth rate. The cellular energy generation has been related with the parameter 'P'. ATP generation was reduced to 55% in the stationary culture on the 8th day (P=0). Also, the adsorption of virus was reduced by nearly 55% in extremely slow growing or stationary culture. Host cells at moderate growth rate (P≥0.15) were found to be optimum for maximizing the yield of viral products

Degeneration of stroma reduces retention of homed cells in bone marrow of lethally irradiated mice

Cytotoxic drugs or irradiation are generally administered before bone marrow (BM) transplantation because of the idea that host bone marrow 'niches' become available to the donor cells for engraftment. How BM stromal cells respond to the radiation, which ultimately modulates grafting of donor cells, is poorly understood. In this study, we examined homing and marrow retention of PKH26<SUP>&#x002B;</SUP> donor cells in BM of age-matched C57BL/6J mice conditioned at different doses of irradiation. When we injected donor cells into mice that received 900 cGy, the percent homing was highest (15.8 &#x00B1; 1.5%) as compared to the lower doses of radiation. Despite the highest levels of homing of donor cells in these mice, about 70% (p &#x003C; 0.005) homed cells were detached from the marrow within 72 h of transplantation. In contrast, a 2- to 2.5-fold (p &#x003C; 0.03) multiplication of homed PKH-26<SUP>&#x002B;</SUP> Sca-1<SUP>&#x002B;</SUP> cells was observed in sublethally irradiated mice. While determining that CD45- CD106<SUP>&#x002B;</SUP> cells in BM of the mice received 900 cGy, we found that more than 80% of cells were depleted. It was also revealed from this investigation that grafted cells conferred partial protection to the endogenous myeloid colony-forming cells from radiation injury. Collectively, the present study implicates radiation-induced degeneration of stroma as a cause of poor retention of donor cells in BM of lethally irradiated mice. These results may have important clinical implications in designing conditioning regimens for BM transplantation

Identification of Long-Term Behavior of Natural Circulation Loops: A Thresholdless Approach from an Initial Response

Natural circulation loop (NCL) systems are buoyancy-driven heat exchangers that are used in various industrial applications. The concept of passive heat exchange in NCL systems is attractive, because there is no need for an externally driven equipment (e.g., a pump) to maintain the fluid circulation. However, relying on buoyancy as the sole driving force may lead to several potential difficulties, one of which is generation of (possibly) time-varying nonlinearities in the dynamical system, where a difference in the time scales of heat transfer and fluid flow causes the flow to change from a steady-state regime to either an oscillatory regime or a flow-reversal regime, both of which are undesirable. In this paper, an algorithm is developed using tools of symbolic time-series analysis (e.g., probabilistic finite state automata (PFSA)) for the purpose of identifying selected regimes of operation in NCL systems using only data from the early transient operation, where the underlying principle is built upon the concept of pattern classification from measurements of fluid-flow dynamics. The proposed method is shown to be capable of identifying the current regime of operation from the initial time response under a given set of operational parameters. The efficacy of regime classification is demonstrated by testing on two datasets, generated from numerical simulation of a MATLAB SimuLink model that has previously been validated with experimental data. The results of the proposed PFSA-based classification are compared with those of a hidden Markov model (HMM) that serves as the baseline

Identification of Long-Term Behavior of Natural Circulation Loops: A Thresholdless Approach from an Initial Response

Natural circulation loop (NCL) systems are buoyancy-driven heat exchangers that are used in various industrial applications. The concept of passive heat exchange in NCL systems is attractive, because there is no need for an externally driven equipment (e.g., a pump) to maintain the fluid circulation. However, relying on buoyancy as the sole driving force may lead to several potential difficulties, one of which is generation of (possibly) time-varying nonlinearities in the dynamical system, where a difference in the time scales of heat transfer and fluid flow causes the flow to change from a steady-state regime to either an oscillatory regime or a flow-reversal regime, both of which are undesirable. In this paper, an algorithm is developed using tools of symbolic time-series analysis (e.g., probabilistic finite state automata (PFSA)) for the purpose of identifying selected regimes of operation in NCL systems using only data from the early transient operation, where the underlying principle is built upon the concept of pattern classification from measurements of fluid-flow dynamics. The proposed method is shown to be capable of identifying the current regime of operation from the initial time response under a given set of operational parameters. The efficacy of regime classification is demonstrated by testing on two datasets, generated from numerical simulation of a MATLAB SimuLink model that has previously been validated with experimental data. The results of the proposed PFSA-based classification are compared with those of a hidden Markov model (HMM) that serves as the baseline