Inspection of the Lower Half of Wing Lap Joints with EMATs

Detection of fatigue cracks at the fastener holes in the lower portion of the C5A wing lap joint is complicated by lack of a direct line of access, and by the presence of fasteners and sealant material. Furthermore, any successful detection procedure must take into account the wide variation in the geometrical features of the joint. In this work, periodic permanent magnet EMATs (electromagnetic-acoustic transducers) have been employed to excite the n=o horizontally polarized shear mode of the skin at 200 kHz and 250 kHz. These modes are partially transmitted into the overlap region joined by the fastener. Spectral analysis of suitably time gated and apodized portions of the reflected waveform have allowed simulated cracks growing out of fastener holes to be detected, and preliminary sizing algorithms have been developed

Test Bed for Quantitative NDE

The ARPA/AFML Interdisciplinary Program for Quantitative Flaw Definition has demonstrated a number of new techniques for quantitatively sizing flaws, as are reported elsewhere in these proceedings. This paper describes a test bed program to assemble and demonstrate these techniques in a single integrated measurement system that will extend them from the idealized geometries that have been considered thus far to geometries that are a better approximation to those that are found in real parts. Included are discussions of the conceptual design of the system, the detailed design and construction of specific modules, and preliminary experimental results. The basic system consists of a Data General Eclipse S/200 minicomputer, a multi-axis microprocessor controller, a Biomation A/D converter, an immersion tank, and a contour following system with six degrees of freedom. A detailed description of the operation of the various components of the system will be given. Included are discussions of the conceptual design of the system, detailed design and construction of specific modules, and preliminary experimental results

Test Bed for Quantitative NDE

The ARPA/AFML Interdisciplinary Program for Quantitative Flaw Definition has demonstrated a number of new techniques for quantitatively sizing flaws, as are reported elsewhere in these proceedings. This paper describes the progress that has been made during the past year on a test bed program to assemble and demonstrate these techniques in a single integrated measurement system that will extend them from the idealized geometries that have been considered thus far to geometries that are a better approximation to those that are found in real parts. The basic system consists of a Data General Eclipse S/200 Minicomputer, a multiaxis microprocessor controller, a Biomation A/D converter, an immersion tank, and a contour following system with six degrees of freedom. The operation of the mechanical system with regard to its accuracy and repeatability will be described. In addition, a review of the conceptual design of the test bed system and experimental results for a number of different flaw geometries will be included. The Test Bed includes a piezoelectric array transducer and associated electronics. The array system will be used both for the imaging of flaws and the gathering of scattering data to use in other flaw characterization algorithms. The success of this portion of the program depends to a large extent on the availability of a suitable array transducer. Some difficulty has been met in obtaining such a transducer and the system design has been slightly modified as a result. The modified system will be described along with a review of the electronic system and an update on its current status. The extended data gathering capability of the system has been demonstrated with several diffusion bonded samples containing spherical and spheroidal voids. The noise associated with these signals is chiefly due. to the grain scattering and varies in amplitude over a wide range. The effects of this noise on the accuracy of the Inverse Born Approximation has been analyzed and the results will be summarized

Sea WiFS Technical Report Series: The fourth SeaWIFS Intercalibration Round-Robin Experiment (SIRREX-4), May 1995

This report documents the fourth Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Intercalibration Round-Robin Experiment (SIRREX-4), which was held at the National Institute of Standards and Technology (NIST) on 3-10 May 1995. The agenda for SIRREX-4 was established by a consensus reached at the conclusion of SIRREX-3: there should be an emphasis on training and work to foster and encourage uniform use of accepted protocols for calibrating radiometric instruments in the laboratory. The goal was to host the activity in a setting where proper techniques could be discussed and demonstrated. It seemed appealing to split the day between morning lectures and afternoon laboratory exercises or practicals. The former gave the user community a chance to present what was important to them and discuss it with acknowledged experts in radiometry, while the latter presented a unique opportunity for training and evaluation in the presence of these same experts. The five laboratory sessions were concerned with (1) determining the responsivity of a spectroradiometer and the spectral radiance of an unknown integrating sphere source, (2) demonstrating spectral field calibration procedures for an integrating sphere using three different instruments, (3) measuring spectral radiance using the plaque method, (4) setting up and aligning lamp calibration transfer standards using the NIST specifications for irradiance measurements, and (5) characterizing radiometric instruments. In addition to documenting some supplemental studies performed outside the laboratory sessions, this report includes an evaluation of the hardware that has been used during the SIRREX activities plus a critical evaluation of SIRREX objectives

A Literature Review of Renal Surgical Anatomy and Surgical Strategies for Partial Nephrectomy

CONTEXT: A detailed understanding of renal surgical anatomy is necessary to optimize preoperative planning and operative technique and provide a basis for improved outcomes. OBJECTIVE: To evaluate the literature regarding pertinent surgical anatomy of the kidney and related structures, nephrometry scoring systems, and current surgical strategies for partial nephrectomy (PN). EVIDENCE ACQUISITION: A literature review was conducted. EVIDENCE SYNTHESIS: Surgical renal anatomy fundamentally impacts PN surgery. The renal artery divides into anterior and posterior divisions, from which approximately five segmental terminal arteries originate. The renal veins are not terminal. Variations in the vascular and lymphatic channels are common; thus, concurrent lymphadenectomy is not routinely indicated during PN for cT1 renal masses in the setting of clinically negative lymph nodes. Renal-protocol contrast-enhanced computed tomography or magnetic resonance imaging is used for standard imaging. Anatomy-based nephrometry scoring systems allow standardized academic reporting of tumor characteristics and predict PN outcomes (complications, remnant function, possibly histology). Anatomy-based novel surgical approaches may reduce ischemic time during PN; these include early unclamping, segmental clamping, tumor-specific clamping (zero ischemia), and unclamped PN. Cancer cure after PN relies on complete resection, which can be achieved by thin margins. Post-PN renal function is impacted by kidney quality, remnant quantity, and ischemia type and duration. CONCLUSIONS: Surgical renal anatomy underpins imaging, nephrometry scoring systems, and vascular control techniques that reduce global renal ischemia and may impact post-PN function. A contemporary ideal PN excises the tumor with a thin negative margin, delicately secures the tumor bed to maximize vascularized remnant parenchyma, and minimizes global ischemia to the renal remnant with minimal complications. PATIENT SUMMARY: In this report we review renal surgical anatomy. Renal mass imaging allows detailed delineation of the anatomy and vasculature and permits nephrometry scoring, and thus precise, patient-specific surgical planning. Novel off-clamp techniques have been developed that may lead to improved outcomes

Head injury from falls in children younger than 6 years of age

The risk of serious head injury (HI) from a fall in a young child is ill defined. The relationship between the object fallen from and prevalence of intracranial injury (ICI) or skull fracture is described. Method Cross-sectional study of HIs from falls in children (<6 years) admitted to UK hospitals, analysed according to the object fallen from and associated Glasgow Coma Score (GCS) or alert, voice, pain, unresponsive (AVPU) and CT scan results. Results Of 1775 cases ascertained (median age 18 months, 54.7% boys), 87% (1552) had a GCS=15/AVPU=alert. 19.3% (342) had a CT scan: 32% (110/342) were abnormal; equivalent to 5.9% of the overall population, 16.9% (58) had isolated skull fractures and 13.7% (47) had ICI (49% (23/47) had an associated skull fracture). The prevalence of ICI increased with neurological compromise; however, 12% of children with a GCS=15/AVPU=alert had ICI. When compared to falls from standing, falls from a person's arms (233 children (mean age 1 year)) had a significant relative OR for a skull fracture/ICI of 6.94 (95% CI 3.54 to 13.6), falls from a building (eg, window or attic) (mean age 3 years) OR 6.84 (95% CI 2.65 to 17.6) and from an infant or child product (mean age 21 months) OR 2.75 (95% CI 1.36 to 5.65). Conclusions Most HIs from a fall in these children admitted to hospital were minor. Infants, dropped from a carer's arms, those who fell from infant products, a window, wall or from an attic had the greatest chance of ICI or skull fracture. These data inform prevention and the assessment of the likelihood of serious injury when the object fallen from is known

Oligopeptide signaling through TbGPR89 drives Trypanosome Quorum sensing

K.R.M. is funded by a Wellcome Trust Investigator Award (103740/Z14/Z) and a Royal Society Wolfson Research merit award (WM140045). The Medical Research Council (MR/M020118/1) supported T.K.S., and the Wellcome Trust supported J.T. (202094/Z/16/Z). M.A. received financial support from the Scottish Universities Life Sciences Alliance (SULSA; https://www.sulsa.ac.uk) and a Medical Research Council strategic grant (J54359).Trypanosome parasites control their virulence and spread by using quorum sensing (QS) to generate transmissible “stumpy forms” in their host bloodstream. However, the QS signal “stumpy induction factor” (SIF) and its reception mechanism are unknown. Although trypanosomes lack G protein-coupled receptor signaling, we have identified a surface GPR89-family protein that regulates stumpy formation. TbGPR89 is expressed on bloodstream “slender form” trypanosomes, which receive the SIF signal, and when ectopically expressed, TbGPR89 drives stumpy formation in a SIF-pathway-dependent process. Structural modeling of TbGPR89 predicts unexpected similarity to oligopeptide transporters (POT), and when expressed in bacteria, TbGPR89 transports oligopeptides. Conversely, expression of an E. coli POT in trypanosomes drives parasite differentiation, and oligopeptides promote stumpy formation in vitro. Furthermore, the expression of secreted trypanosome oligopeptidases generates a paracrine signal that accelerates stumpy formation in vivo. Peptidase-generated oligopeptide QS signals being received through TbGPR89 provides a mechanism for both trypanosome SIF production and reception.Publisher PDFPeer reviewe