Soft x-ray telescope for Solar-A: design evolution and lessons learned

1992 ◽  
Author(s):  
Marilyn E. Bruner
2022 ◽  
pp. 004947552110433
Author(s):  
James Shelton ◽  
Sara Dorman ◽  
Yinna Kim ◽  
Phillipa Thorpe ◽  
Badri Narayan ◽  
...  

Circular frames are a successful way of treating difficult fractures and non-unions. At our institution (CSC) in Phnom Penh, Cambodia, our method differs from developed healthcare systems in that we do not use x-ray to site the frames. A retrospective cohort study was performed between CSC and a UK LRS unit. Demographics, diagnosis, frame type, pre- and post-op deformity, proximal and distal construct alignment comparative to the tibia, and time to union or failure. 70 patients in total were identified and were randomly selected from a hospital in UK. Demographics & deformity were similar and failed to reach significant difference on testing: union rate 70% v. 82%, time to union 9.8 v. 8.5 months, and radiation exposure mean 0 v. 74 cGy/cm2 (range 6.4–326.7). These are startlingly homogenous results considering the differing resources available. We believe that ring fixators are a viable treatment method in austere environments where image intensifiers are unavailable, and demand no unnecessary radiation exposure.


2014 ◽  
Vol 29 (S1) ◽  
pp. S2-S7
Author(s):  
Pamela S. Whitfield

In many ways, studies of materials and minerals by powder-diffraction techniques are complementary, with techniques honed in one field equally applicable to the other. Many of the example techniques described within this paper were developed for analysis of functional materials and subsequently applied to minerals. However, in a couple of cases, the study of new minerals was the initiation into techniques later used in materials-based studies. Hopefully they will show that the study of new minerals structures can provide opportunities to add new methodologies and approaches to future problems. In keeping with the Australian X-ray Analytical Association many of the examples have an Australian connection, the materials ranging from organics to battery materials.


Author(s):  
Navid Asadizanjani ◽  
Sina Shahbazmohamadi ◽  
Mark Tehranipoor ◽  
Domenic Forte

Abstract Reverse engineering of electronics systems is performed for various reasons ranging from honest ones such as failure analysis, fault isolation, trustworthiness verification, obsolescence management, etc. to dishonest ones such as cloning, counterfeiting, identification of vulnerabilities, development of attacks, etc. Regardless of the goal, it is imperative that the research community understands the requirements, complexities, and limitations of reverse engineering. Until recently, the reverse engineering was considered as destructive, time consuming, and prohibitively expensive, thereby restricting its application to a few remote cases. However, the advents of advanced characterization and imaging tools and software have counteracted this point of view. In this paper, we show how X-ray micro-tomography imaging can be combined with advanced 3D image processing and analysis to facilitate the automation of reverse engineering, and thereby lowering the associated time and cost. In this paper, we demonstrate our proposed process on two different printed circuit boards (PCBs). The first PCB is a four-layer custom designed board while the latter is a more complex commercial system. Lessons learned from this effort can be used to both develop advanced countermeasures and establish a more efficient workflow for instances where reverse engineering is deemed necessary. Keywords: Printed circuit boards, non-destructive imaging, X-ray tomography, reverse engineering.


Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1244
Author(s):  
Natsumi Noda ◽  
Shohei Yamashita ◽  
Yoshio Takahashi ◽  
Megumi Matsumoto ◽  
Yuma Enokido ◽  
...  

Ferrous saponite is a secondary mineral that can be used to reveal the redox state of past aqueous environments on Mars. In mineralogical analyses for ferrous saponite formed in laboratory simulations or contained in future returned samples from Mars, its oxidation by the Earth’s air could be problematic due to the high redox sensitivity. Here, we performed micro X-ray diffraction and scanning transmission X-ray microscopy analyses for a single particle of synthesized ferrous saponite without any exposure to air. The sample was reanalyzed after air exposure for 10–18 h to assess the adequacy of our anoxic preparation/measurement methods and the impacts of air on the sample. We found that the crystal structures agreed with ferrous saponite, both before and after air exposure; however, ferrous iron in saponite was partially oxidized, at least until 0.1–1 μm from the surface, after air exposure at the submicron scale, forming micro-vein-like Fe(III)-rich features. Together with our results of infrared spectroscopy of ferrous saponite, we showed that oxidation of octahedral iron occurred rapidly and heterogeneously, even in a short time of air exposure without any structural rearrangement. Since ferrous saponite is expected to exist on carbonaceous asteroids and icy dwarf planets, our methodology is also applicable to mineralogical studies of samples returned from these bodies.


2013 ◽  
Vol 103 (11) ◽  
pp. 112403 ◽  
Author(s):  
Tianhan Wang ◽  
Virat Mehta ◽  
Yoshihiro Ikeda ◽  
Hoa Do ◽  
Kentaro Takano ◽  
...  

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jason Pui Yin Cheung ◽  
Kam Yim Sze ◽  
Kenneth Man Chee Cheung ◽  
Teng Zhang

Abstract Background The first magnetically controlled growing rod (MCGR) was implanted in 2009. Since then multiple complications have been identified that have helped drive the development of the MCGR and its surgery. The aim of this report is to illustrate how identified complications in the first MCGR helped with developments in the past decade and to report a unique failure mechanism with stud fracture close to the barrel opening. Case presentation A 5-year old girl with a scoliosis of 58.5 degrees at T1–9 and 72.8 degrees at T9-L4 had a single MCGR inserted and anchored at T3–4 and L3–4. At postoperative 13 months the MCGR was noted to have lost of distraction between lengthening episodes due to unrestricted turning of the internal magnet. To prevent further loss of distraction, an external magnet was placed outside the skin to prevent the magnet from turning back. The overall balance was suboptimal and after the rod was fully distracted, proximal junctional kyphosis occurred. Subsequently, the MCGR was modified with an internal keeper plate to prevent loss of distraction and a dual set of these rods were implanted when the patient was 9 years old. Extension proximally to C7-T1 was done to manage the proximal junctional kyphosis. Her spinal balance improved and distractions continued. She subsequently developed add-on below and the piston rod was not aligned with the actuator. The lumbar spine was also observed to have autofusion. She subsequently had final fusion surgery performed at the age of 15 from C7-L4 leaving a residual tilt below to avoid fusion to the pelvis. The final extracted rod on the left side indicated the “crooked rod sign” on X-ray and rod dissections revealed a new failure mechanism of stud fracture close to the barrel opening. Body fluids and tissue may infiltrate the rod despite no obvious deformation or fractures resulting in hastened wearing of the threads. Conclusions There are various complications associated with MCGRs that are related to rod design and surgical inexperience. Repeated rod stalling is not recommended with potential stud fracture and “crooked rod sign”. Rotor stalling and thread wearing which indicates rod failure still require solutions.


2020 ◽  
Author(s):  
Ralf Gellert

<p>Three generations of the Alpha-Particle-X-ray-Spectrometer (APXS) have been part of the science suite on all four landed NASA Mars rovers so far. Using x-ray spectroscopy following excitation with alpha particles and x-rays from <sup>244</sup>Cm radioactive sources, so far about 2000 samples have been investigated along the combined traverse of ~85km on the surface of Mars.</p><p>The APXS reports 16 standard elements in all samples and additional trace elements like Ge, Cu, Ga, Rb, Sr, As, Se, Y and Pb if at elevated levels. The sample spot of ~ 20 mm diameter is often large enough to represent bulk content, though small enough to reveal evidence for certain minerals through element correlations when oversampled in rasters. The results from all missions revealed large scale sedimentary formations, like Murray and Burns indicating specific environmental conditions in the past. The soil was found similar at all sites, representing a well mixed global crust component. APXS geochemical data were used for important constraints of complimentary mineralogy results, ground truth for orbiters and comparison to Martian meteorites.</p><p>Results from the ongoing Curiosity mission and the long living MER rovers will be discussed. Additionally, some very successful applications and investigations that were serendipitously developed after launch will be reviewed. Part of the presentation will be devoted to the unique challenges, trade-offs during design and lessons learned from the long operation of the instrument. The combination of APXS, XRD and Moesbauer results from MER and MSL with future fine scale XRF results of the soil at the Mars 2020 landing site might shed a light into the enigmatic amorphous phase, which could represent a record of the past alteration processes on Mars.</p>


2001 ◽  
Vol 36 (12) ◽  
pp. 1605-1616 ◽  
Author(s):  
J. I. Trombka ◽  
L. R. Nittler ◽  
R. D. Starr ◽  
L. G. Evans ◽  
T. J. Mccoy ◽  
...  

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