Compton Imaging Tomography for Nondestructive Evaluation of Spacecraft Thermal Protection Systems

Novel nondestructive evaluation (NDE) systems based on a recently pioneered Compton Imaging Tomography (CIT) technique [1-4] are currently being developed by Physical Optics Corporation (POC). CIT provides high-resolution, three-dimensional, Compton scattered X-ray imaging of the internal structure of evaluated objects, using a set of acquired two-dimensional, Compton scattered X-ray images of consecutive cross sections of these objects. Unlike conventional computerized tomography, CIT requires only one-sided access to objects, has no limitation on the dimensions and geometry of such objects, and can be applied to large, multilayer, nonuniform objects. Also, CIT does not require any contact with objects during its application. Currently POC is developing a CIT-based tool that addresses NASA’s need for NDE of lightweight, rigid, and/or flexible ablative materials (PICA, Avcoat, AETB, etc.), and provides noncontact, one-sided in situ operation for accurate detection, identification, and precise spatial localization and measurements of internal and surface defects (cracks, voids, delaminations, porosity, and inclusions), and evaluation of bondlines and in-depth integrity of such materials and also large-area multilayer thermal protection system (TPS) structures with complex geometries. The feasibility of the tool was successfully demonstrated in NDE of various TPS samples provided by NASA. This tool can detect individual internal defects with dimensions about 1 mm3, and bondline defects less than 6 mm by 6 mm by the thickness of the adhesive of ≤100 μm. Also, it can detect anisotropy of the TPS materials. It also allows precise detection of flaws and in-service damage for ceramic, metal matrix composite, textile polymeric, aluminum/ titanium materials/structures, providing quantitative information on residual structural performance. The current scanning speed of TPS structures is about 2.5 min/ft2 (25 min/m2): ~250 ft2 of an entire Orion TPS can be scanned in 10-12 hr

Pathophysiology of renal tubular obstruction: Therapeutic role of synthetic RGD peptides in acute renal failure

In his famous work On the Natural Faculties, Galen of Pergamum introduced the idea of “attraction” [δλκηζ] as the principal mode of kidney function: the attraction of blood to the kidney, he claimed, results in the production of urine [1]. Though unproven in Galen's ancient times and entirely rejected by the later generations as a mechanistic explanation of renal function, the concept of attraction has not only survived, albeit in a modified form, but has become one of the cornerstone principles of modern physiology and our current understanding of the pathophysiology of processes as diverse as platelet aggregation, metastases, immune recognition and wound healing, to name a few, all of which are governed by adhesion molecules. Here we review the role of adhesion molecules in the pathophysiology of tubular obstruction, focusing on the integrins and their newly recognized function in it.The importance of renal tubular obstruction in the pathogenesis of acute renal failure (ARF) was brought to center stage by a series of elegant microdissection studies by Oliver, MacDowell and Tracy [2]. Using servo-null pressure monitoring of the proximal tubular pressure in diverse models of ARF, investigators have provided solid evidence for the elevation in hydrostatic intratubular pressure concomitant with the unchanged stop-flow and estimated glomerular capillary pressures, further confirming the tubulo-obstructive component of this syndrome [3–5]. It has been concluded, therefore, that tubular obstruction and elevated proximal tubular pressure equilibrate glomerular filtration pressure, thus leading to the persisting oliguria. Necrotic epithelial cells have been postulated to provide the matrix for casts obstructing the tubular lumen. Recent findings of viable epithelial cells in the urine of patients and experimental animals with ARF, however, cast doubt on the postulated schema and suggest the possibility of epithelial cell detachment as an important contributor to the development of tubular obstruction [6–8].In the following discussion we develop this theme, providing data on the possible mechanism(s) of tubular obstruction in ischemic ARF, and on the therapeutic strategies in and benefits of inhibiting tubular obstruction, and suggest some future directions of this fledgling field of investigations

Підготовка персоналу авіаційного пошуку і рятування в інформаційному освітньому середовищі закладу післядипломної освіти

Abstract: The authors consider the problem of personnel training to improve the efficiency of search and rescue operations. Under challenging conditions of an aviation accident, the success of rescuing and surviving the victims depends on the professional readiness of these coordination centers and specialists. In the course of the research, it was found that this situation is due to the lack of a unified and standardized approach to forming training programs for aviation search and rescue personnel on a single object – an airplane in suffering distress. Therefore, the unification of educational programs and the certification process has become one of its primary functions. And for the system of professional development, the search for the ways to ensure the continuity of this process is actualized, which is possible only under the conditions of creation and implementation of a systemically organized information educational environment of the establishment of postgraduate education. At the Institute of Public Administration and Research in Civil Protection, such an environment functions on the LMS MOODLE platform. Its methodological basis is represented by a system approach that allows identifying the main functional elements; to model and describe the processes of each component and the functional relationships between them. Innovative author’s technology is introduced in which classes are organized and conducted regardless of institutional forms (full-time, part-time, distance) both in computer-equipped classrooms of the educational stablishment and for independent work in a remote mode outside of it.Авторами статті розглядається проблема підготовки персоналу для підвищення ефективності функціонування пошуково-рятувального забезпечення польотів. В складних умовах авіаційної події успіх рятування та виживання постраждалих залежить від професійної готовності фахівців координаційних авіаційних центрів пошуку і рятування та спеціалістів, що безпосередньо організують проведення аварійно-рятувальних робіт. За результатами експерименту, проведеного з використанням методики оцінки рівня компетентності, з’ясовано, що такий стан пов'язаний з відсутністю уніфікованого і стандартизованого підходу до формування навчальних програм підвищення кваліфікації спеціалістів авіаційного пошуку і рятування щодо єдиного об’єкту – повітряного судна, що зазнає (зазнало) лиха. Оскільки забезпечення підвищення кваліфікації зазначених фахівців покладено на Державну службу надзвичайних ситуацій України, то уніфікація освітніх програм і процес сертифікації стають однією з основних її функцій. А для системи підвищення кваліфікації актуалізується пошук шляхів забезпечення неперервності цього процесу, що уможливлюється лише за умов створення і реалізації системно організованого інформаційного освітнього середовища закладу післядипломної освіти. В Інституті державного управління і наукових досліджень у сфері цивільного захисту таке середовище розгортається на платформі LMS MOODLE. Його методологічною основою є системний підхід, який уможливлює визначення головних функціональних елементів, змоделювати та описати процеси кожного окремого елементу, а також функціональні взаємозв’язки між ними. Запроваджено інноваційну авторську технологію комп’ютерно орієнтованого дидактичного проектування інформаційного освітнього середовища, в якому зорганізуються і проводяться заняття, незалежно від інституційних форм (очної, заочної, дистанційної) як в комп’ютерно обладнаних аудиторіях навчального закладу, так і для самостійної роботи у віддаленому режимі поза його межами

Simplified Dynamic Phantom for Pediatric Renography: A Description of Instrument and Its Performance

Objective(s): Renography is used for the diagnostic evaluation of pediatric patients with a suspected obstruction of urinary tract or impaired renal function. The recommended dose for children have been released by the European Association of Nuclear Medicine, Society of Nuclear Medicine and Molecular Imaging, and Japanese Society of Nuclear Medicine. Since acquisition counts in dynamic scintigraphy are affected by the administered doses and sensitivity of the scintillation camera, the scan procedure should be determined independently. In this study, we constructed simplified dynamic phantom imitating pediatric renography and tested its performance.Methods: Simplified dynamic phantom consisted of three components (i.e.,infusion, imitated kidney, and drainage sections). The infusion rates (mL/min) were determined by comparing the time activity curves obtained from patientswith normal renal function. The time-points of the maximum counts (Tmax), as well as the two-thirds and one-half of the maximum counts (T2/3 and T1/2) were measured in different doses using the phantom with the best-match infusion rateand duration, and low-energy general-purpose (LEGP) or low-energy highresolution (LEHR) collimators and applying different attenuations.Results: The best-match infusion rates of the phantom to imitate the time activity curve of the normal renal function were 42.0, 1.0, 0.6, and 0.3 mL/min in the arterial, secretory, early-excretory, and late-excretory phases, respectively. When 30 MBq, LEHR collimator and non-water-equivalent phantom were applied, Tmax, T2/3, and T1/2 were 242±15.3, 220±10.0 and 317±25.2 seconds, respectively. Using LEGP collimator and (3 MBq of activity) 5-cm water-equivalent phantom, Tmax, T2/3, and T1/2 values were estimated as 242±5.8, 213±11.5, and 310±17.3 sec, respectively.Conclusion: Our simplified dynamic phantom for pediatric renography could imitate the time activity curves obtained from patients with normal renal function. Tmax, T2/3, and T1/2 could be measured under various settings of dose,collimator, and tissue attenuation

Compton imaging tomography for nondestructive evaluation of large multilayer aircraft components and structures

Novel nondestructive evaluation (NDE) systems based on a recently pioneered Compton Imaging Tomography (CIT) technique [1-4 are currently being developed by Physical Optics Corporation (POC). CIT provides high-resolution, three-dimensional (3D), Compton scattered X-ray imaging of the internal structure of evaluated objects, using a set of acquired two-dimensional Compton scattered X-ray images of consecutive cross sections of these objects. Unlike conventional computerized tomography, CIT requires only one-sided access to objects, has no limitation on the dimensions and geometry of such objects, and can be applied to large, multilayer, nonuniform objects. Also, CIT does not require any contact with objects during its application. POC is developing CIT-based tools that address Air Force needs for depot or in-field in situ NDE of various large, nonuniform, multilayer aluminum/titanium/composite and honeycomb sandwich aircraft/spacecraft structures with complex geometries, and provide accurate detection, identification, and precise 3D localization and measurement of possible internal and surface defects (corrosion, cracks, voids, delaminations, porosity, and inclusions), and also disbonds, core and skin defects, and intrusion of foreign fluids (e.g., fresh and salt water, oil) inside honeycomb sandwich structures. The feasibility of the tool was successfully demonstrated in NDE of various aircraft structure samples provided by the Air Force, Lockheed Martin, Boeing, SpaceX, Virgin Galactic, etc., and in situ NDE of C-5 and C-130 aircraft. Such tools can detect and localize individual internal defects with dimensions about 2 mm3, and honeycomb disbond defects less than 6 mm by 6 mm by the thickness of the adhesive of ≤100 μm. The current scanning speed of aircraft/spacecraft structures is about 2-3 min/ft2 (20-30 min/m2).</p

Compton Imaging Tomography for Nondestructive Evaluation of Large Multilayer Aircraft Components and Structures

Novel nondestructive evaluation (NDE) systems based on a recently pioneered Compton Imaging Tomography (CIT) technique [1-4 are currently being developed by Physical Optics Corporation (POC). CIT provides high-resolution, three-dimensional (3D), Compton scattered X-ray imaging of the internal structure of evaluated objects, using a set of acquired two-dimensional Compton scattered X-ray images of consecutive cross sections of these objects. Unlike conventional computerized tomography, CIT requires only one-sided access to objects, has no limitation on the dimensions and geometry of such objects, and can be applied to large, multilayer, nonuniform objects. Also, CIT does not require any contact with objects during its application. POC is developing CIT-based tools that address Air Force needs for depot or in-field in situ NDE of various large, nonuniform, multilayer aluminum/titanium/composite and honeycomb sandwich aircraft/spacecraft structures with complex geometries, and provide accurate detection, identification, and precise 3D localization and measurement of possible internal and surface defects (corrosion, cracks, voids, delaminations, porosity, and inclusions), and also disbonds, core and skin defects, and intrusion of foreign fluids (e.g., fresh and salt water, oil) inside honeycomb sandwich structures. The feasibility of the tool was successfully demonstrated in NDE of various aircraft structure samples provided by the Air Force, Lockheed Martin, Boeing, SpaceX, Virgin Galactic, etc., and in situ NDE of C-5 and C-130 aircraft. Such tools can detect and localize individual internal defects with dimensions about 2 mm3, and honeycomb disbond defects less than 6 mm by 6 mm by the thickness of the adhesive of ≤100 μm. The current scanning speed of aircraft/spacecraft structures is about 2-3 min/ft2 (20-30 min/m2).</p

Compton Imaging Tomography for Nondestructive Evaluation of Spacecraft Thermal Protection Systems

Novel nondestructive evaluation (NDE) systems based on a recently pioneered Compton Imaging Tomography (CIT) technique [1-4] are currently being developed by Physical Optics Corporation (POC). CIT provides high-resolution, three-dimensional, Compton scattered X-ray imaging of the internal structure of evaluated objects, using a set of acquired two-dimensional, Compton scattered X-ray images of consecutive cross sections of these objects. Unlike conventional computerized tomography, CIT requires only one-sided access to objects, has no limitation on the dimensions and geometry of such objects, and can be applied to large, multilayer, nonuniform objects. Also, CIT does not require any contact with objects during its application. Currently POC is developing a CIT-based tool that addresses NASA’s need for NDE of lightweight, rigid, and/or flexible ablative materials (PICA, Avcoat, AETB, etc.), and provides noncontact, one-sided in situ operation for accurate detection, identification, and precise spatial localization and measurements of internal and surface defects (cracks, voids, delaminations, porosity, and inclusions), and evaluation of bondlines and in-depth integrity of such materials and also large-area multilayer thermal protection system (TPS) structures with complex geometries. The feasibility of the tool was successfully demonstrated in NDE of various TPS samples provided by NASA. This tool can detect individual internal defects with dimensions about 1 mm3, and bondline defects less than 6 mm by 6 mm by the thickness of the adhesive of ≤100 μm. Also, it can detect anisotropy of the TPS materials. It also allows precise detection of flaws and in-service damage for ceramic, metal matrix composite, textile polymeric, aluminum/ titanium materials/structures, providing quantitative information on residual structural performance. The current scanning speed of TPS structures is about 2.5 min/ft2 (25 min/m2): ~250 ft2 of an entire Orion TPS can be scanned in 10-12 hr.</p