2,041 research outputs found
Viking '75 spacecraft design and test summary. Volume 1: Lander design
The Viking Mars program is summarized. The design of the Viking lander spacecraft is described
Some Activities of MISSE 6 Mission
The objective of the Materials International Space Station Experiment (MISSE) is to study the performance of novel materials when subjected to the synergistic effects of the harsh space environment for several months. In this paper, a few laser and optical elements from NASA Langley Research Center (LaRC) that have been flown on MISSE 6 mission will be discussed. These items were characterized and packed inside a ruggedized Passive Experiment Container (PEC) that resembles a suitcase. The PEC was tested for survivability due to launch conditions. Subsequently, the MISSE 6 PEC was transported by the STS-123 mission to International Space Station (ISS) on March 11, 2008. The astronauts successfully attached the PEC to external handrails and opened the PEC for long term exposure to the space environment. The plan is to retrieve the MISSE 6 PEC by STS-128 mission in August 2009
Lab-on-a-chip Thermoelectric and Solid-phase Immunodetection of Biochemical Analytes and Extracellular Vesicles: Experimental and Computational Analysis
Microfluidics is the technology of controlling and manipulating fluids at the microscale. Microfluidic platforms provide precise fluidic control coupled with low sample volume and an increase in the speed of biochemical reactions. Lab-on-a-chip platforms are used for detection and quantification of biochemical analytes, capture, and characterization of various proteins, sensitive analysis of cytokines, and isolation and detection of extracellular vesicles (EVs). This study focuses on the development of microfluidic and solid-phase capture pin platforms for the detection of cytokines, extracellular vesicles, and cell co-culture. The fabrication processes of the devices, experimental workflows, numerical analysis to identify optimal design parameters, and reproducibility studies have been discussed. Layer-by-layer assembly of polyelectrolytes has been developed to functionalize glass and stainless-steel substrates with biotin for the immobilization of streptavidinconjugated antibodies for selective capture of cytokines or EVs. Microstructure characterization techniques (SEM, EDX, and fluorescence microscopy) have been implemented to assess the efficiency of substrate functionalization. A detailed overview of current methods for purification and analysis of EVs is discussed as well.
Additionally, the dissertation demonstrates the feasibility of a calorimetric microfluidic immunosensor with an integrated antimony-bismuth (Sb/Bi) thermopile sensor for the detection of cytokines with picomolar sensitivity. The developed platform can be used for the universal detection of both exothermic or endothermic reactions. A three-dimensional numerical model was developed to define the critical design parameters that enhance the sensitivity of the platform. Mathematical analyses identified the optimal combinations of substrate material and dimensions that will maximize the heat transfer to the sensor. Lab-on-a-chip cell co-culture platform with integrated pneumatic valve was designed, numerically characterized, and fabricated. This device enables the reversible separation of two cell culture chambers and serves as a tool for the effective analysis of cell-to-cell communication. Intercellular communication is mediated by extracellular vesicles. A protocol for the functionalization of stainless-steel probe with exosomespecific CD63 antibody was developed. The efficiency of the layer-by-layer deposition of polyelectrolytes and the effectiveness of biotin and streptavidin covalent boding were characterized using fluorescent and scanning electron microscopy
A lunar base reference mission for the phased implementation of bioregenerative life support system components
Previous design efforts of a cost effective and reliable regenerative life support system (RLSS) provided the foundation for the characterization of organisms or 'biological processors' in engineering terms and a methodology was developed for their integration into an engineered ecological LSS in order to minimize the mass flow imbalances between consumers and producers. These techniques for the design and the evaluation of bioregenerative LSS have now been integrated into a lunar base reference mission, emphasizing the phased implementation of components of such a BLSS. In parallel, a designers handbook was compiled from knowledge and experience gained during past design projects to aid in the design and planning of future space missions requiring advanced RLSS technologies. The lunar base reference mission addresses in particular the phased implementation and integration of BLS parts and includes the resulting infrastructure burdens and needs such as mass, power, volume, and structural requirements of the LSS. Also, operational aspects such as manpower requirements and the possible need and application of 'robotics' were addressed
Aeronautics and space report of the President, 1982 activities
Achievements of the space program are summerized in the area of communication, Earth resources, environment, space sciences, transportation, aeronautics, and space energy. Space program activities of the various deprtments and agencies of the Federal Government are discussed in relation to the agencies' goals and policies. Records of U.S. and world spacecraft launchings, successful U.S. launches for 1982, U.S. launched applications and scientific satellites and space probes since 1975, U.S. and Soviet manned spaceflights since 1961, data on U.S. space launch vehicles, and budget summaries are provided. The national space policy and the aeronautical research and technology policy statements are included
Optothermal Trapping of Fluorescent Nanodiamonds using a Drop-casted Gold Nanoparticle
Deterministic optical manipulation of fluorescent nanodiamonds (FNDs) in a
fluid environment has emerged as an experimental challenge in multimodal
biological imaging. The design and development of nano-optical trapping
strategies to serve this purpose is an important task. In this letter, we show
how a drop-casted gold nanoparticle (Au np) can facilitate optothermal
potential to trap individual entities of FNDs using a low power density
illumination (532nm laser, 0.1 mW/m). We utilize the same trapping
excitation source to capture the spectral signatures of single FNDs and track
their position. Furthermore, by tracking the dynamics of FND, we measure the
trapping stiffness as a function of laser power and surfactant concentration
and emphasize their relevance as vital parameters for nano-manipulation. Our
trapping configuration combines the thermoplasmonic fields generated by
individual gold nanoparticles and the optothermoelectric effect facilitated by
surfactants to realize a nano-optical trap down to a single FND 120 nm in size.
We envisage that our drop-casting platform can be extrapolated to perform
targeted, low-power trapping, manipulation, and multimodal imaging of FNDs
inside biological systems such as cells.Comment: 17 pages, 4 figures, 3 tables. Supplementary videos may be found at:
https://drive.google.com/drive/folders/1gkW9g5Z7Fhl4i3ZQUOBQYuUYAPrHykzY?usp=sharin
The Biology Instrument for the Viking Mars Mission
Two Viking spacecraft have successfully soft landed on the surface of Mars. Each carries, along with other scientific instruments, one biology laboratory with three different experiments designed to search for evidence of living microorganisms in material sampled from the Martian surface. This 15.5-kg biology instrument which occupies a volume of almost 28.3 dm3 is the first to carry out an in situ search for extraterrestrial life on a planet. The three experiments are called the pyrolytic release, labeled release, and gas exchange. The pyrolytic release experiment has the capability to measure the fixation of carbon dioxide or carbon monoxide into organic matter. The labeled release experiment detects metabolic processes by monitoring the production of volatile carbon compounds from a radioactively labeled nutrient mixture. The gas exchange experiment monitors the gas changes in the head space above a soil sample which is either incubated in a humid environment or supplied with a rich organic nutrient solution. Each experiment can analyze a soil sample as it is received from the surface or, as a control, analyze a soil which has been heated to above 160C. Each instrument has the capability to receive four different soils dug from the Martian surface and perform a number of analysis cycles depending on the particular experiment. This paper describes in detail the design and operation of the three experiments and the supporting subsystems
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Nanomaterials characterization and bio-chemical sensing using microfabricated devices
textA variety of nanostructured materials have been synthesized in recent
years. These nanomaterials have potential applications in areas spanning
computing, energy conversion, sensing, and biomedicine. Because of size
confinement effects, furthermore, these nanomaterials are expected to show very
different physical properties from those of their bulk counterparts. The
measurement of their properties, however, has been very challenging due to their
small dimensions. Similarly, it remains a challenge to detect chemical and
biomolecular species due to their small dimensions.
This dissertation presents the development of microelectromechanical
systems (MEMS) devices for the characterization of thermophysical properties of
nanomaterials and for the detection of chemical species and biological cells.
The thermophysical property of one-dimensional (1D) nanomaterials was
measured using a batch-fabricated microdevice consisting of two adjacent
symmetric silicon nitride membranes suspended by long silicon nitride beams.
Three methods were developed to assemble nanomaterials with the measurement
devices. Those three methods include a wet deposition process, an in-situ
chemical vapor deposition technique, and an electric-field-assisted assembly
method. During the measurement, one membrane is Joule-heated to cause heat
conduction through the nanomaterials to the other membrane, allowing for the
measurement of thermal conductance and Seebeck coefficient. The electrical
conductance can also be measured using the microdevice. The temperaturedependent
properties of an individual single-wall carbon nanotubes (SWCNs) and
SWCN bundles were measured. Measurement sensitivity, errors, and uncertainty
were examined. The obtained thermal conductivity of an individual SWCN is
found to be much higher than bundles of SWCNs in the range of 2000-11000
W/m-K at room temperature, in agreement with theoretical predictions.
Furthermore, the thermal conductivity of bundles of SWCNs are found to be
suppressed by contact resistance between interconnected SWCNs in the bundle.
The microdevice has also been integrated with metal oxide nanobelts for
chemical sensing. The sensing mechanism is based on surface oxidation-reduction
(redox) processes that change the electrical conductance of the nanobelt. The
sensor was found to be highly sensitive to inflammable and toxic gas species
including nitrogen dioxide (NO2), ethanol, and dimethyl methylphosphonate
(DMMP). Furthermore, it eliminated the sensor poisoning effects that have
limited the wide use of polycrystalline metal-oxide based sensors. The experiment
is a step towards the large scale integration of nanomaterials with microsystems,
and such integration via an electric-field-directed assembly approach can
potentially enable the fabrication of low-power, ultra-sensitive, and selective
integrated nanosensor systems.
The electric field manipulation technique has not only been used to
assemble nanomaterials with MEMS, but also been used to focus biological cells
in a microfluidic channel for cytometry applications. Flow cytometry is a
powerful and versatile method of rapidly analyzing large populations of cells and
other particulate or molecular analytes that have been captured on the surface of
carrier particles. However, the key components of the system, hydrodynamic
focusing and optical systems, make conventional cytometers complex, large, and
expensive. To eliminate these drawbacks, a dielectrophoretic particle focusing
technique combined with MEMS is explored to replace the hydrodynamic
focusing mechanism.
To focus particles, microelectrodes are patterned on the circumference of
the channel to generate AC fringing fields that result in negative dielectrophoretic
forces directing cells from all directions to the center of the channel. An ellipticlike
microfluidic channel has been fabricated by isotropic etching of soda lime
glass wafers and a subsequent wafer-bonding process. Experiments with
microbeads and human leukemia HL60 cells and an analysis using a thin shell
model indicate that biological cells can be focused using an AC voltage of an
amplitude up to 15 Vp-p and a frequency below 100 kHz, respectively. This
design eliminates the sheath flow and the fluid control system that makes
conventional cytometers bulky, complicated, and difficult to operate, and offers
the advantages of a portable standalone instrument as well as a module that could
potentially be integrated with on-chip impedance or optical sensors into a micro
total analysis system.Mechanical Engineerin
Power Approaches for Implantable Medical Devices.
Implantable medical devices have been implemented to provide treatment and to assess in vivo physiological information in humans as well as animal models for medical diagnosis and prognosis, therapeutic applications and biological science studies. The advances of micro/nanotechnology dovetailed with novel biomaterials have further enhanced biocompatibility, sensitivity, longevity and reliability in newly-emerged low-cost and compact devices. Close-loop systems with both sensing and treatment functions have also been developed to provide point-of-care and personalized medicine. Nevertheless, one of the remaining challenges is whether power can be supplied sufficiently and continuously for the operation of the entire system. This issue is becoming more and more critical to the increasing need of power for wireless communication in implanted devices towards the future healthcare infrastructure, namely mobile health (m-Health). In this review paper, methodologies to transfer and harvest energy in implantable medical devices are introduced and discussed to highlight the uses and significances of various potential power sources
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