2,421 research outputs found

    Polar tongue of ionization (TOI) and associated Joule heating intensification investigated during the magnetically disturbed period of 1–2 October 2001

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    We investigate storm-enhanced density (SED) and polar tongue of ionization (TOI) over North America under southward Interplanetary Magnetic Field conditions. We focus on the 30 September to 1 October 2001 medium magnetic storm's recovery phase (Period 1) and on the last substorm (Period 2) of the following 2 October substorm series. We aim to study the SED-TOI structure in the time frame of solar wind energy input to the magnetosphere-ionosphere system and in terms of Joule heating. We utilize GPS total electron content maps tracking SED plume and polar TOI, and spectrogram images detecting polar rain and precipitation void and thus evidencing dayside merging. The variations of merging electric (E) field (E) and its mapped-down polar equivalent (E), energy input efficiency (EI), and modeled Joule heating rate (Q) are monitored. Results show multiple Joule heating intensification points implying multiple energy deposition points at high latitudes where the magnetic pole was one of the preferred locations. During the higher EI (~1.5%) Period 2, the polar TOI was associated with a well-defined strong Q intensification and with polar rain (or void) on the dayside (or nightside). During the lower EI (~0.5%) Period 1, only weak Q intensification occurred in the absence of both polar TOI and polar rain. We highlight the polar TOI's potential impact on the thermosphere. We conclude that (i) strong (E ≈ 5 mV/m during Period 2) or weak (E ≈ 0.5–2 mV/m during Period 1) E facilitated energy deposition close to the magnetic pole and (ii) E could be used as a diagnostic of the polar TOI's intensity

    Investigating magnetosphere‐ionosphere‐thermosphere (M‐I‐T) coupling occurring during the 7‐8 November 2004 superstorm

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    In this study, we investigate the shock‐sheath driven 7–8 November 2004 superstorm for its flux transfer events and resultant flow channel (FC) events and associated neutral (DN) and electron (Ne) density features in order to understand better the underlying coupled magnetosphere (M) and ionosphere (I) processes and responses in the thermosphere (T). We focus on the (i) subauroral, auroral, and polar cap regions, (ii) localized DN increases and associated Ne features and FCs developed, and (iii) energy deposition occurred. Results show the development of localized DN increases (1) within/over FCs and associated enhanced small‐scale field aligned currents suggesting Joule heating driving upwelling during forward and reverse polar convections, (2) appearing with Ne increases during storm‐enhanced density (SED) events suggesting strong M‐I‐T coupling and with Ne depletions during plasmaspheric erosion events suggesting weak M‐I‐T coupling, and (3) in the thermosphere's increasing NO and continuously low O/N2 composition regions. During erosion events, strong storm‐time subauroral polarization streams (SAPS) E fields developed. Meanwhile the well‐developed plasmapause appeared with decreased total electron content (TEC) on its poleward side and with increased TEC and Ne (appearing as a shoulder feature that is the signature of SED) on its equatorward side. From these we conclude that although strong M‐I‐T coupling was apparent during SED events, M‐I‐T coupling was also strong during erosion events when the combination of strong convection E field and large storm‐time SAPS E fields eroded the high‐latitude region and thus decreased the high‐latitude Ne and TEC

    Evaluation of Raman spectroscopy for online monitoring of cell culture product quality

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    Recent years have shown an increase in the development and application of Raman spectroscopy for process monitoring and control in the biopharmaceutical industry. While Raman spectroscopy has been successfully used to predict concentration of cell counts and conventional metabolites, limited work has been presented on its capability to measure product titer and quality. Here, we present results using Raman spectroscopy to obtain online predictions of CHO antibody titer, charge variants, size variants, and glycan species across several products and cell lines. Products assessed include standard antibodies and complex molecular formats

    Effect of Aspartate Supplementation on Athletic Performance in Young Men

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    D-aspartic acid has been suggested to enhance athletic performance by regulating the hypothalamus-pituitary-gonadal axis by increasing plasma testosterone. Aspartate supplementation may be useful to increase testosterone for individuals with low plasma testosterone due to aging and other conditions. PURPOSE: To determine the effect of D-aspartic acid supplementation on athletic performance in young male athletes. METHODS: After screening for ACSM low risk, 9 healthy male athletes (average age = 22y, body weight = 82.7 kg and body fat = 10.4%) were randomized to two groups for supplementation using a double blinded parallel arm experimental design. They ingested either 3 grams of d-aspartic acid (Aspartate, n=5) or a Placebo (n=4) for 14 days supplied in capsule form. Subjects recorded and replicated previous 3 day diets prior to testing. Physical assessments were performed prior to and after supplementation included a peak VO2 test by cycle ergometer, 1 maximal repetition bench press and 1 maximal repetition squat (average values ±SD before supplementation were 41.7 ±6.4 ml/kg/min, 117.9 ±11.1 kg and 151.7 ±19.0 kg, respectively). RESULTS: The Aspartate group improved performance in 1 maximal repetition bench press by 4.5 ±1.6kg (average ±SEM, p=0.03) and 1 maximal repetition squat by 8.2 ±3.8kg (average ±SEM, p=0.04). No change in performance measures were observed in the Placebo group. Body composition did not change for either group. CONCLUSION: D-aspartic acid supplementation may lead to improved acute skeletal muscle synthesis improving upper and lower body muscle performance

    Process intensification: Case study with a CHO-based monoclonal antibody production process

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    Standard platform technologies for cell culture processing provide simple and robust strategies to meet rapid timelines for early process development and ease of manufacturing. However, when there is a need to achieve high antibody titers due to high product demand, both culture media and feed strategies must be customized for specific cell lines. Two case studies will describe the strategies employed as part of a process intensification effort to overcome the limitations of a platform Phase III cell culture process. The first case study will demonstrate an intensified fed-batch process development effort performed to maximize production of a CHO-based monoclonal antibody, while maintaining product quality comparability with the original Phase III process. The second case study will describe the evaluation of a concentrated fed-batch process using alternating tangential flow filtration to retain the protein in the bioreactor, and achieve even higher titers in support of the high product demand forecast. These case studies will show that the intensified fed-batch process improved titers by 50%, and the concentrated fed-batch process improved titers by 100% relative to the fed-batch platform

    Infrared Imaging of Boundary Layer Transition Flight Experiments

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    The Hypersonic Thermodynamic Infrared Measurement (HYTHIRM) project is presently focused on near term support to the Shuttle program through the development of an infrared imaging capability of sufficient spatial and temporal resolution to augment existing on-board Orbiter instrumentation. Significant progress has been made with the identification and inventory of relevant existing optical imaging assets and the development, maturation, and validation of simulation and modeling tools for assessment and mission planning purposes, which were intended to lead to the best strategies and assets for successful acquisition of quantitative global surface temperature data on the Shuttle during entry. However, there are longer-term goals of providing global infrared imaging support to other flight projects as well. A status of HYTHIRM from the perspective of how two NASA-sponsored boundary layer transition flight experiments could benefit by infrared measurements is provided. Those two flight projects are the Hypersonic Boundary layer Transition (HyBoLT) flight experiment and the Shuttle Boundary Layer Transition Flight Experiment (BLT FE), which are both intended for reducing uncertainties associated with the extrapolation of wind tunnel derived transition correlations for flight application. Thus, the criticality of obtaining high quality flight data along with the impact it would provide to the Shuttle program damage assessment process are discussed. Two recent wind tunnel efforts that were intended as risk mitigation in terms of quantifying the transition process and resulting turbulent wedge locations are briefly reviewed. Progress is being made towards finalizing an imaging strategy in support of the Shuttle BLT FE, however there are no plans currently to image HyBoLT

    Formation and evolution of the ionospheric plasma density shoulder and its relationship to the superfountain effects investigated during the 6 November 2001 great storm

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    This study investigates the 6 November 2001 great storm’s impact on the topside ionosphere utilizing data from the onboard TOPEX/Poseidon-NASA altimeter, Defense Meteorological Satellite Program–Special Sensor Ions, Electrons and Scintillation instruments and ACE interplanetary observatory. A set of field-aligned profiles demonstrate the storm evolution, caused by the precursor and promptly penetrating interplanetary eastward electric (E) fields, and strong equatorward winds reducing chemical loss, during the long-duration negative BZ events. At daytime-evening, the forward fountain experienced repeated strengthening, as the net eastward E field suddenly increased. The resultant symmetrical equatorial anomaly exhibited a continuous increase,while the energy inputs at both auroral regions were similar. In both hemispheres, by progressing poleward, a midlatitude shoulder exhibiting increased plasma densities, a plasma-density dropoff (steep gradient) and a plasma depletion appeared. These features were maintained while the reverse fountain operated. At the dropoff, elevated temperatures indicated the plasmapause. Consequently, the plasma depletion was the signature of plasmaspheric erosion. In each hemisphere, an isolated plasma flow, supplying the minimum plasma, was detected at the shoulder. Plasmaspheric compression, due to the enhanced E fields, could trigger this plasma flow. Exhibiting strong longitudinal variation at evening-nighttime, the shoulder increased 306% over the southeastern Pacific, where the nighttime Weddell Sea Anomaly (WSA) appeared before the storm. There, the shoulder indicated the storm-enhanced equatorward section of the quiet time WSA. Owing to the substantial equatorward plasmapause movement, a larger poleward section of the quiet time WSA eroded away, leaving a large depletion behind. This study reports first these (northern, southern) plasma flows and dramatic storm effects on a nighttime WSA

    Weed Presence Altered Biotic Stress and Light Signaling in Maize Even When Weeds were Removed Early in the Critical Weed‐free Period

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    Weed presence early in the life cycle of maize (typically, from emergence through the 8 to 12 leaf growth stage) can reduce crop growth and yield and is known as the critical weed‐free period (CWFP). Even if weeds are removed during or just after the CWFP, crop growth and yield often are not recoverable. We compared transcriptome responses of field‐grown hybrid maize at V8 in two consecutive years among plants grown under weed‐free and two weed‐stressed conditions (weeds removed at V4 or present through V8) using RNAseq analysis techniques. Compared with weed‐free plant responses, physiological differences at V8 were identified in all weed‐stressed plants and were most often associated with altered photosynthetic processes, hormone signaling, nitrogen use and transport, and biotic stress responses. Even when weeds were removed at V4 and tissues sampled at V8, carbon: nitrogen supply imbalance, salicylic acid signals, and growth responses differed between the weed‐stressed and weed‐free plants. These underlying processes and a small number of developmentally important genes are potential targets for decreasing the maize response to weed pressure. Expression differences of several novel, long noncoding RNAs resulting from exposure of maize to weeds during the CWFP were also observed and could open new avenues for investigation into the function of these transcription units

    Experimental Investigation of Project Orion Crew Exploration Vehicle Aeroheating in AEDC Tunnel 9

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    An investigation of the aeroheating environment of the Project Orion Crew Entry Vehicle has been performed in the Arnold Engineering Development Center Tunnel 9. The goals of this test were to measure turbulent heating augmentation levels on the heat shield and to obtain high-fidelity heating data for assessment of computational fluid dynamics methods. Laminar and turbulent predictions were generated for all wind tunnel test conditions and comparisons were performed with the data for the purpose of helping to define uncertainty margins for the computational method. Data from both the wind tunnel test and the computational study are presented herein

    Aeroheating Testing and Predictions for Project Orion CEV at Turbulent Conditions

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    An investigation of the aeroheating environment of the Project Orion Crew Exploration Vehicle was performed in the Arnold Engineering Development Center Hypervelocity Wind Tunnel No. 9 Mach 8 and Mach 10 nozzles and in the NASA Langley Research Center 20 - Inch Mach 6 Air Tunnel. Heating data were obtained using a thermocouple-instrumented approx.0.035-scale model (0.1778-m/7-inch diameter) of the flight vehicle. Runs were performed in the Tunnel 9 Mach 10 nozzle at free stream unit Reynolds numbers of 1x10(exp 6)/ft to 20x10(exp 6)/ft, in the Tunnel 9 Mach 8 nozzle at free stream unit Reynolds numbers of 8 x 10(exp 6)/ft to 48x10(exp 6)/ft, and in the 20-Inch Mach 6 Air Tunnel at free stream unit Reynolds numbers of 1x10(exp 6)/ft to 7x10(exp 6)/ft. In both facilities, enthalpy levels were low and the test gas (N2 in Tunnel 9 and air in the 20-Inch Mach 6) behaved as a perfect-gas. These test conditions produced laminar, transitional and turbulent data in the Tunnel 9 Mach 10 nozzle, transitional and turbulent data in the Tunnel 9 Mach 8 nozzle, and laminar and transitional data in the 20- Inch Mach 6 Air Tunnel. Laminar and turbulent predictions were generated for all wind tunnel test conditions and comparisons were performed with the experimental data to help define the accuracy of computational method. In general, it was found that both laminar data and predictions, and turbulent data and predictions, agreed to within less than the estimated 12% experimental uncertainty estimate. Laminar heating distributions from all three data sets were shown to correlate well and demonstrated Reynolds numbers independence when expressed in terms of the Stanton number based on adiabatic wall-recovery enthalpy. Transition onset locations on the leeside centerline were determined from the data and correlated in terms of boundary-layer parameters. Finally turbulent heating augmentation ratios were determined for several body-point locations and correlated in terms of the boundary-layer momentum Reynolds number
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