Index to nasa tech briefs, issue number 2

Annotated bibliography on technological innovations in NASA space program

Accommodation requirements for microgravity science and applications research on space station

Scientific research conducted in the microgravity environment of space represents a unique opportunity to explore and exploit the benefits of materials processing in the virtual abscence of gravity induced forces. NASA has initiated the preliminary design of a permanently manned space station that will support technological advances in process science and stimulate the development of new and improved materials having applications across the commercial spectrum. A study is performed to define from the researchers' perspective, the requirements for laboratory equipment to accommodate microgravity experiments on the space station. The accommodation requirements focus on the microgravity science disciplines including combustion science, electronic materials, metals and alloys, fluids and transport phenomena, glasses and ceramics, and polymer science. User requirements have been identified in eleven research classes, each of which contain an envelope of functional requirements for related experiments having similar characteristics, objectives, and equipment needs. Based on these functional requirements seventeen items of experiment apparatus and twenty items of core supporting equipment have been defined which represent currently identified equipment requirements for a pressurized laboratory module at the initial operating capability of the NASA space station

Reactive inkjet printing and functional inks : a versatile route to new programmed materials

Starting as an ink dispensing tool for documents and images, inkjet printing has emerged as an important instrument for delivering reactive fluids, into a means for creating new, programmed materials. Inkjet is a processing technology with some very unique capabilities, which allows the handling of materials in the picoliter range, and the creation of functionality in new, previously unexplored ways. In particular, drop-on-demand technology provides the chance to dispense liquids in picoliter/nanoliter quantities to very specific locations, with minimal material loss, and in a contact-free manner. This dramatic scale-down of production, not just miniaturization but "nanonization", affords materials that would be either too costly or otherwise inaccessible by other manners. As this is still an emerging technology, there remain a lot of opportunities to pioneer new applications. The underlying, unifying concept behind the chapters of this thesis has been an interest in investigating how inkjet printing, combined with reactive inks, can lead to new applications, new devices, and new materials, wherein unique functionality is imparted as a direct result of the confluence between microfluidic processing, chemistry, and life science. The ability to deliver uniform, sub-nanoliter droplets to specific locations opens up new possibilities that did not exist before. Inherent in the geometry of such droplets, the volume of liquid dispensed also offers some special utility. Based on the aforementioned diameters, drop-on-demand inkjet printing can deliver volumes in the range of approximately 0.5 to 1,000 pL; the direct writing attributes of inkjet ensure that these droplets are not only precise, but can be delivered to a specific location, giving them a "home address". This combination of precise, reproducible, small aliquots and precision deposition is especially important for preparing high-density analytical arrays, as discussed in Chapter 1 on inkjet printing of proteins. In the case of highly specialized proteins such as reactive enzymes or antibodies, where available materials are often limited, the ability to dispense precise quantities in a reproducible fashion means that small amounts of precious material can be used parsimoniously to perform thousands of experiments without compromising the quality of the data. For drop-on-demand printing, droplets normally produced by inkjet printing are commonly in the range of 10 to 125 µm in diameter, depending on the physical characteristics of the fluid, the nozzle used, and the printing conditions; taking advantage of the this aliquot size has some unique attributes that make dispensing highly suitable to materials science challenges that have gone unmet. In the second chapter of this thesis, this size domain is taken advantage of for use in tissue engineering, where it is used to create soft, cell-scale porogenic structures by the use of a reversible, rapid alginate gelation reaction to freeze droplet structures in place. By switching to a continuous inkjet device, larger volumes of beads in the size domain of 100 to 500 µm can be achieved, opening up prospects for pore sizes matching those needed for hosting capillaries. By incorporating reversible hydrogels as a motif in these applications, these controlled cell-scale dimensions can be retained during key processing steps, and then removed (or eroded) later after they have served their function. Extending the concept to the task of dispensing living cells, in Chapter 3, printed alginate structures are used for cell encapsulation. By adjusting the printing conditions to prevent jet break-up before alginate hardening, continuous, one-dimensional "living threads" can be created, which allow for cell cultures to be handled and woven into desired complex patterns. In addition to their role as basic building materials for tissue engineering scaffolds, the alginate threads provide a stable, bio-friendly environment for culturing different cell types, with cells exhibiting a high post-processing viability rate. In Chapter 4, the lower limits of single cell printing are explored, in the concept of "one cell-one well", where the attributes of inkjet printing are used to dispense individual cells. By careful selection of droplet size and accounting of cell concentrations, the statistical probability of single cell printing can be optimized, yielding spatially addressable arrays of isolated living cell cultures on a surface. Additional steps necessary to prevent cells from dehydration are also outlined, offering access to high density arrays of isolated living single cells on glass slides, where each individual droplet acts as independent nanoincubator, hosting intrinsically monoseptic cell cultures in parallel. In addition to describing the theoretical limits of single-pass cell printing experiment designs, an outline is given for experimental designs for tuning single particulate dispensing probability to any value desired between 0 and 1. The focus of Chapter 5 relates to reactive inkjet printing of ultrathin films on surfaces. For systems with moderately good surface wetting, such as polar solvents on glass or metal oxides, inkjet printed droplets result in features ranging approximately from 20 to 300 µm in diameter per droplet. By first printing a thiol-functionalized heterochelic linker and covalently bonding it to the print surface, the surface will accommodate subsequent thiol-ene click reactions only with original monolayer, and only where the first and second deposition features overlap. This combination of spatial selectivity as well as chemoselectivity allows for the preparation of a wide range of monolayers on a printed surface, in a format well-suited to automated surface characterization techniques, as was illustrated using XPS. In Chapters 6, two different categories of irreversible polymerization reactions are described, where print features are reacted in a specific pattern that is process unique. Printable ionogels are developed, which impart conductivity to printed patterns, and consequently, functionality to only those locations where the material has been deposited. Also in Chapter 6, the first example of a moisture-sensitive reactive printing is outlined, where a diisocyanate is combined with different polyols within seconds to create highly crosslinked, ultra-stiff surfaces, which can be built up into three dimensions by successive layering. The topics outlined in this thesis are intended to illustrate the breadth of how inkjet technology can be utilized to support a diverse field of materials science applications — particularly when coupled with modular, off-the-shelf synthetic transformations. The incorporation of synthetic chemistry into inkjet extends the application of inkjet from dispensing static materials merely from a cartridge onto a target, into a dynamic tool for transforming these materials into something new. At the same time, inkjet printing and other allied microfluidics tools enable chemistry experiments (and by extension, life science experiments) on a scale that would otherwise be challenging to realize by other means. The two driving forces of high-throughput experiment design, miniaturization and automation, are both embodied in this dispensing technique, and consequently inkjet printing is a rapidly evolving discipline; it is the intent of this work and the examples given to underscore the diversity offered by this technology

Component-Level Electronic-Assembly Repair (CLEAR) System Architecture

This document captures the system architecture for a Component-Level Electronic-Assembly Repair (CLEAR) capability needed for electronics maintenance and repair of the Constellation Program (CxP). CLEAR is intended to improve flight system supportability and reduce the mass of spares required to maintain the electronics of human rated spacecraft on long duration missions. By necessity it allows the crew to make repairs that would otherwise be performed by Earth based repair depots. Because of practical knowledge and skill limitations of small spaceflight crews they must be augmented by Earth based support crews and automated repair equipment. This system architecture covers the complete system from ground-user to flight hardware and flight crew and defines an Earth segment and a Space segment. The Earth Segment involves database management, operational planning, and remote equipment programming and validation processes. The Space Segment involves the automated diagnostic, test and repair equipment required for a complete repair process. This document defines three major subsystems including, tele-operations that links the flight hardware to ground support, highly reconfigurable diagnostics and test instruments, and a CLEAR Repair Apparatus that automates the physical repair process

Automated longitudinal monitoring of in vivo protein aggregation in neurodegenerative disease C. elegans models

Background: While many biological studies can be performed on cell-based systems, the investigation of molecular pathways related to complex human dysfunctions - e.g. neurodegenerative diseases - often requires long-term studies in animal models. The nematode Caenorhabditis elegans represents one of the best model organisms for many of these tests and, therefore, versatile and automated systems for accurate time-resolved analyses on C. elegans are becoming highly desirable tools in the field. Results: We describe a new multi-functional platform for C. elegans analytical research, enabling automated worm isolation and culture, reversible worm immobilization and long-term high-resolution imaging, and this under active control of the main culture parameters, including temperature. We employ our platform for in vivo observation of biomolecules and automated analysis of protein aggregation in a C. elegans model for amyotrophic lateral sclerosis (ALS). Our device allows monitoring the growth rate and development of each worm, at single animal resolution, within a matrix of microfluidic chambers. We demonstrate the progression of individual protein aggregates, i.e. mutated human superoxide dismutase 1 - Yellow Fluorescent Protein (SOD1-YFP) fusion proteins in the body wall muscles, for each worm and over several days. Moreover, by combining reversible worm immobilization and on-chip high-resolution imaging, our method allows precisely localizing the expression of biomolecules within the worms' tissues, as well as monitoring the evolution of single aggregates over consecutive days at the sub-cellular level. We also show the suitability of our system for protein aggregation monitoring in a C. elegans Huntington disease (HD) model, and demonstrate the system's ability to study long-term doxycycline treatment-linked modification of protein aggregation profiles in the ALS model. Conclusion: Our microfluidic-based method allows analyzing in vivo the long-term dynamics of protein aggregation phenomena in C. elegans at unprecedented resolution. Pharmacological screenings on neurodegenerative disease C. elegans models may strongly benefit from this method in the near future, because of its full automation and high-throughput potential

Clinical Pipette

The current technique of administering Botox with a syringe and plunger leaves room for user error and imprecision. The project team, in collaboration with UMass Medical School, has designed a handheld, automated syringe pump for clinical use. With such a device, injection technique is made more accurate, efficient, and safer for patients. The device was shown to dispense an average of 25.5 and 98 uL when programmed to administer 25 and 100 uL respectively. Our results confirm that our device falls within the 10 uL-accuracy minimum, showing its efficacy as an administration tool. The device was also able to inject into skin as exhibited through successful trials into 1% collagen hydrogels. Our team has set a series of future electronic and mechanical updates to improving our desig

Chemistry Lab Automation via Constrained Task and Motion Planning

Chemists need to perform many laborious and time-consuming experiments in the lab to discover and understand the properties of new materials. To support and accelerate this process, we propose a robot framework for manipulation that autonomously performs chemistry experiments. Our framework receives high-level abstract descriptions of chemistry experiments, perceives the lab workspace, and autonomously plans multi-step actions and motions. The robot interacts with a wide range of lab equipment and executes the generated plans. A key component of our method is constrained task and motion planning using PDDLStream solvers. Preventing collisions and spillage is done by introducing a constrained motion planner. Our planning framework can conduct different experiments employing implemented actions and lab tools. We demonstrate the utility of our framework on pouring skills for various materials and two fundamental chemical experiments for materials synthesis: solubility and recrystallization.Comment: Equal author contribution from Naruki Yoshikawa, Andrew Zou Li, Kourosh Darvish, Yuchi Zhao and Haoping X

Cumulative index to NASA Tech Briefs, 1963-1965

Annotated bibliography of NASA technical briefs on electrical, energy sources, materials, life sciences, and mechanical informatio

The influence of electric charge and electric fields on the formation and duration of water boules

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Consideration is given to the conditions under which floating drops of water, here referred to as water boules, form, exist and coalesce. Particular emphasis is placed on the part played by electric charge and electric fields in these processes. The literature is reviewed in terms of both the phenomenon of floating drops and of the development of hydrostatics, hydrodynamics and electrohydrodynamics as applicable to the subject. . Experimental investigations to ascertain the boundary conditions to the influence of such electrical forces are described, together with observations of the connected electrical events. It is confirmed that boules will fail to form at all, i) under conditions of high humidity, and ii) in the presence of an electric field greater than a certain value. This is investigated experimentally, and shown to be approximately 34kV/m, this figure being about two-thirds that previously reported. Boules traversing a plane water surface are demonstrated to acquire additional charge in the process. In the case of drops dispensed from a grounded source, forming boules and crossing a bulk water surface some 15cm wide, the additional charge gathered is significant. Boules of 0.055g mass were found to have a mean charge of 1.6 x 10-12C on leaving a water surface, having arrived as drops with an average charge of 5.8 x 10-14C. Possible charging mechanisms are discussed. The origin of the initial drop charge is considered, and measurements of this are presented from (i), conventional Faraday cup determinations, and (ii), induction methods applied to free-falling drops. Experimental investigation of the time-dependent electrical records of the coalescence of a dispensed drop with a plane water surface shows the whole coalescence process to have a two-part form. This detail is commonly hidden within more conventional charge-transfer measurements. For the coalescences investigated experimentally an small initial event is shown to occur, involving a charge transfer in the range 1.2 – 4.8 x 10-12C. Oscillograms taken from a large number of coalescences show this preliminary event to be a general feature of the coalescence process, with a number of such traces being appended to the thesis. This initial event is followed by a larger one where the signs of the signals from the drop and the bulk surface are opposite to those of the initial event, and whose potential magnitude is broadly in agreement with that anticipated by double layer disruption. The interfacial potential difference necessary for the onset of instability and subsequent coalescence in the case of closely opposed drops is shown to be dependent on the relative humidity of the ambient air. Consideration is given to G I Taylor’s equation describing the critical potential for the onset of instability between closely spaced drops, and this is shown experimentally to require correction for different humidities. It is demonstrated that the critical potential, Vc, at a relative humidity of 100% is approximately 50% of that at 40% RH. Possible reasons for this are discussed, drawing attention to the problem of establishing an accurate DC relative permittivity value for vapour-laden air in small interfacial gaps. The rôle of evaporation in modifying the system geometry is considered experimentally and theoretically, and shown to be significant only for humidities < 50%. The complex nature of the interface in the case of very small air-gaps is discussed, together with the implications of these investigations for the interfacial stability of a floating drop or boule system. A theoretical model based on a consideration of the complex liquid-air-liquid interface as a capacitive system is developed, and shown to be in good agreement with practical observations. This model demonstrates that the parts played by electrical forces, together with environmental factors, are likely to be significant in terms of coalescence at stages prior to gap thinning to the point where London/van-der-Waals forces become dominant. Interfacial potentials are calculated in a boule system at a number of times between 0.1 and 10 seconds, and shown to be sufficient to promote instability and coalescence. Full data based on a number of values of instability potentials is appended to the thesis. Development of the model raises questions concerning the validity of currently accepted values both for interfacial stability in small gaps and for the relative permittivity of humid air in similar situations. Suggestions are made for future work in such areas, together with possible methodologies. The phenomenon of floating water drops is therefore shown to be compatible with the general coalescence process, the event time being modified by such diverse factors as the impact energy with the surface, the ambient humidity and the magnitude of the initial drop charge. The latter is shown to be the dominant factor in the case of drops arriving on a clean surface with low kinetic energies, with the small charge inherent on any water drop being sufficient to produce potentials adequate to promote eventual instability