Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Characterisation of a nuclear cave environment utilising an autonomous swarm of heterogeneous robots

As nuclear facilities come to the end of their operational lifetime, safe decommissioning becomes a more prevalent issue. In many such facilities there exist ‘nuclear caves’. These caves constitute areas that may have been entered infrequently, or even not at all, since the construction of the facility. Due to this, the topography and nature of the contents of these nuclear caves may be unknown in a number of critical aspects, such as the location of dangerous substances or significant physical blockages to movement around the cave. In order to aid safe decommissioning, autonomous robotic systems capable of characterising nuclear cave environments are desired. The research put forward in this thesis seeks to answer the question: is it possible to utilise a heterogeneous swarm of autonomous robots for the remote characterisation of a nuclear cave environment? This is achieved through examination of the three key components comprising a heterogeneous swarm: sensing, locomotion and control. It will be shown that a heterogeneous swarm is not only capable of performing this task, it is preferable to a homogeneous swarm. This is due to the increased sensory and locomotive capabilities, coupled with more efficient explorational prowess when compared to a homogeneous swarm

Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Design of Novel Sensors and Instruments for Minimally Invasive Lung Tumour Localization via Palpation

Minimally Invasive Thoracoscopic Surgery (MITS) has become the treatment of choice for lung cancer. However, MITS prevents the surgeons from using manual palpation, thereby often making it challenging to reliably locate the tumours for resection. This thesis presents the design, analysis and validation of novel tactile sensors, a novel miniature force sensor, a robotic instrument, and a wireless hand-held instrument to address this limitation. The low-cost, disposable tactile sensors have been shown to easily detect a 5 mm tumour located 10 mm deep in soft tissue. The force sensor can measure six degrees of freedom forces and torques with temperature compensation using a single optical fiber. The robotic instrument is compatible with the da Vinci surgical robot and allows the use of tactile sensing, force sensing and ultrasound to localize the tumours. The wireless hand-held instrument allows the use of tactile sensing in procedures where a robot is not available

Low Frequency Bio-Electrical Impedance Mammography and Dielectric Measurement

Assessment of electrical impedance of biological tissues at low frequencies offers a great potential for a safe, simple, and low-cost medical breast imaging techniques such as mammography. As such, in this dissertation a mammography method which uses tissue electrical impedance to detect breast malignancies was developed. The dissertation also introduces a new technique for measuring the dielectric properties of biological tissues at low frequencies. The impedance mammography technique introduced in this study is founded on the assumption that dielectric values of breast malignancies are significantly higher than the dielectric values of normal breast tissues. While previous studies have shown that this assumption is valid at high frequencies (50MHz-20GHz), less research efforts have been dedicated to ascertain the validity of such assumption at low frequencies (in silico and tissue mimicking phantom studies. Results of this investigation suggest that imaging the electrical impedance properties of biological tissues through the proposed electrical impedance mammography can be potentially employed for breast cancer detection in a reliable and safe manner

Research and technology

The NASA Lewis Research Center's research and technology accomplishments for fiscal year 1987 are summarized. It comprises approximately 100 short articles submitted by staff members of the technical directorates and is organized into four sections: aeronautics, aerospace technology (which includes space communications), space station systems, and computational support. A table of contents by subject was developed to assist the reader in finding articles of special interest

Index to 1981 NASA Tech Briefs, volume 6, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1981 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Hypertrophic scar therapy : pressure-induced remodelling and its determinents

Hypertrophic scars are cosmetically unattractive products of abnormal wound healing and, if they occur over flexor aspects of joints, considerable functional impairment often results. Pressure, as a therapy for hypertrophic- scarring has considerable attraction since it is effective and nonsurgical. Previous reports of this therapy have not quantified magnitudes or durations of pressure required to induce remodelling. Correlation of these parameters is necessary to define guidelines to optimise pressure therapy. Measurement of pressure applied to hypertrophic scars by garments with elastic properties was achieved using a monitoring system based on a thin (0.2mm) flat (1cm²) capacitive transducer. Pressures of 15 - 40mnmHg produced, in general, accelerated scar remodelling with superior cosmesis resulting from higher pressures. Clinical studies suggested that 6-9 months pressure is sufficient to induce permanent remodelling, although studies of rates of collagen biosynthesis in pressure-treated and untreated scars indicated 9- 12 months pressure was necessary. Two types of pressure applying garments, Tubigrip and Lycra, were studied and compared. Tubigrip garments demonstrated superior elastic properties for maintaining pressure with-time. Investigations of two hypotheses for pressure-induced remodelling were performed. A first hypothesis that pressure induces ischaemia in scars, implying remodelling by autolysis, was investigated with vital microscopy using a hamster cheek pouch model. Pressure magnitudes which induced scar remodelling did not disturb the microcirculation sufficiently to cause permanent damage, therefore this hypothesis was thought unlikely to be correct. A second hypothesis that pressure-induced vascular changes produce scar resorption via a collagen-based mechanism was investigated using a radioactive isotope assay of the rate of collagen biosynthesis. The time for which the rate of collagen biosynthesis approached normal scar levels was reduced by half in pressure-treated compared to untreated scars. A two-phase scar remodelling theory was introduced comprising a pressure-magnitude dependent phase followed by a time-dependent phase. The second hypothesis was thought to be partially correct and the complexity of the pressure-induced remodelling mechanism is discussed.Hypertrophic scars are cosmetically unattractive products of abnormal wound healing and, if they occur over flexor aspects of joints, considerable functional impairment often results. Pressure, as a therapy for hypertrophic- scarring has considerable attraction since it is effective and nonsurgical. Previous reports of this therapy have not quantified magnitudes or durations of pressure required to induce remodelling. Correlation of these parameters is necessary to define guidelines to optimise pressure therapy. Measurement of pressure applied to hypertrophic scars by garments with elastic properties was achieved using a monitoring system based on a thin (0.2mm) flat (1cm²) capacitive transducer. Pressures of 15 - 40mnmHg produced, in general, accelerated scar remodelling with superior cosmesis resulting from higher pressures. Clinical studies suggested that 6-9 months pressure is sufficient to induce permanent remodelling, although studies of rates of collagen biosynthesis in pressure-treated and untreated scars indicated 9- 12 months pressure was necessary. Two types of pressure applying garments, Tubigrip and Lycra, were studied and compared. Tubigrip garments demonstrated superior elastic properties for maintaining pressure with-time. Investigations of two hypotheses for pressure-induced remodelling were performed. A first hypothesis that pressure induces ischaemia in scars, implying remodelling by autolysis, was investigated with vital microscopy using a hamster cheek pouch model. Pressure magnitudes which induced scar remodelling did not disturb the microcirculation sufficiently to cause permanent damage, therefore this hypothesis was thought unlikely to be correct. A second hypothesis that pressure-induced vascular changes produce scar resorption via a collagen-based mechanism was investigated using a radioactive isotope assay of the rate of collagen biosynthesis. The time for which the rate of collagen biosynthesis approached normal scar levels was reduced by half in pressure-treated compared to untreated scars. A two-phase scar remodelling theory was introduced comprising a pressure-magnitude dependent phase followed by a time-dependent phase. The second hypothesis was thought to be partially correct and the complexity of the pressure-induced remodelling mechanism is discussed

Development of highly sensitive multimodal tactile sensor

The sense of touch is crucial for interpreting exteroceptive stimuli, and for moderating physical interactions with one’s environment during object grasping and manipulation tasks. For years, tactile researchers have sought a method that will allow robots to achieve the same tactile sensing capabilities as humans, but the solution has remained elusive. This is a problem for people in the medical and robotics communities, as prosthetic and robotic limbs provide little or no force feedback during contact with objects. During object manipulation tasks, the inability to control the force (applied by the prosthetic or robotic hand to the object) frequently results in damage to the object. Moreover, amputees must compensate for the lack of tactility by paying continuous visual attention to the task at hand, making even the simplest task a frustrating and time-consuming endeavor. We believe that these challenges of object manipulation might best be addressed by a closed feedback loop with a tactile sensory system that is capable of detecting multiple stimuli. To this end, the goal of our research is the development of a tactile sensor that mimics the human sensory apparatus as closely as possible. Thus far, tactile sensors have been unable to match the human sensory apparatus in terms of simultaneous multimodality, high resolution, and broad sensitivity. In particular, previous sensors have typically been able to sense either a wide range of forces, or very low forces, but never both at the same time; and they are designed for either static or dynamic sensing, rather than multimodality. These restrictions have left them unsuited to the needs of robotic applications. Capacitance-based sensors represent the most promising approach, but they too must overcome many limitations. Although recent innovations in the touch screen industry have resolved the issue of processing complexity, through the replacement of clunky processing circuits with new integrated circuits (ICs), most capacitive sensors still remain limited by hysteresis and narrow ranges of sensitivity, due to the properties of their dielectrics. In this thesis, we present the design of a new capacitive tactile sensor that is capable of making highly accurate measurements at low force levels, while also being sensitive to a wide range of forces. Our sensor is not limited to the detection of either low forces or broad sensitivity, because the improved soft dielectric that we have constructed allows it to do both at the same time. To construct the base of the dielectric, we used a geometrically modified silicone material. To create this material, we used a soft-lithography process to construct microfeatures that enhance the silicone’s compressibility under pressure. Moreover, the silicone was doped with high-permittivity ceramic nanoparticles, thereby enhancing the capacitive response of the sensor. Our dielectric features a two-stage microstructure, which makes it very sensitive to low forces, while still able to measure a wide range of forces. Despite these steps, and the complexity of the dielectric’s structure, we were still able to fabricate the dielectric using a relatively simple process. In addition, our sensor is not limited to either static or dynamic sensing; unlike previous sensors, it is capable of doing both simultaneously. This multimodality allows our sensor to detect fluctuating forces, even at very low force levels. Whereas past researchers have used separate technologies for static and dynamic sensing, our dynamic sensing unit is formed with same capacitive technology as the static one. This was possible because of the high sensitivity of our dielectric. We used the entire surface area effectively, by integrating the single dynamic sensing taxel on the same layer as the static sensing taxels. Essentially, the dynamic taxel takes the shape of the lines of a grid, filling in the spaces between the individual static taxels. For further optimization, the geometry of the dynamic taxel has been redesigned by fringing miniature traces of the dynamic taxel within the static taxels. In this way, the entire surface of the sensor is sensitive to both dynamic and static events. While this design slightly reduces the area that is covered by the static taxels, the trade-off is justified, as the capacitive behavior is boosted by the edge effect of the capacitor. The fusion of an innovative dielectric with a capacitive sensing IC has produced a highly sensitive tactile sensor that meets our goals regarding resolution, noise immunity, and overall performance. It is sensitive to forces ranging from 1 mN to 15 N. We verified the functionality of our sensor by mounting it on several of the most popular mechanical hands. Our grasp assessment experiments delivered promising results, and showed how our sensor might be further refined so that it can be used to accurately estimate the outcome of an attempted grasp. In future, we believe that combining an advanced robotic hand with the sensor we have developed will allow us to meet the demand for human-like tactile sensing abilities