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In laser powder bed fusion additive manufacturing (AM), the number of build cycles required for a powder to go from its virgin state to a state that can alter final part mechanical properties is currently unknown. While ideal, the use of virgin powder for every AM build is not practical or economical. It is critical to investigate new methods that will help mitigate these cost drivers and enable the use of recycled powder in AM. Presented here is initial work on the use of an inductively coupled plasma (ICP) process to recondition AM powders used in laser and electron beam powder bed fusion, highlighting some challenges faced while developing optimum process parameters. The manuscript focuses on the three-dimensional characterization of used powder, before and after the plasma reconditioning process, in order to quantitatively understand the result of the ICP process on the shape and porosity of the particles. A distinct change in the morphology of the powder was observed before and after the ICP where most, but not all, irregular shaped powder particles and multi-particles were converted into more spherical particles. A detailed analysis of the percentage of spherical and non-spherical particles before and after the ICP process is also included, as well as the process’ effect on particle porosity, which was different for the two powders used, Inconel 718 and Ti-6Al-4V. The results indicate the value of using the ICP process as a viable option for recycling of these two powders.

X-ray interferometry provides a dark-field image, essentially a small-angle X-ray scattering image, of the voids and print defects in an additively manufactured polymer object. The interferometers used were tuned to scattering length 2–5 μm and configured to measure scattering along both vertical and horizontal directions. The samples studied included Stanford Bunnies, fabricated from acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA), and a quadratic test object fabricated from PLA. The dark-field projection images show orientation-dependent X-ray scattering which is due to anisotropic voids and gaps at the filament-to-filament interface in these fused deposition modeling additive manufacturing objects. SEM corroborates the existence of gaps between filaments. The absorption and dark-field volumes are used to correlate printhead trajectory with print defect density. The absorption volume is used to generate perimeter points slice-by-slice, and from these points, the 2D curvature is calculated. There is a slight increase in X-ray scattering, hence print defect density, at regions with high curvature. Two X-ray interferometry techniques were used: stepped-grating and single-shot. As currently developed, stepped-grating has the larger field-of-view—examination of an entire test object—whilst single-shot has the potential for real-time, in situ measurement of the printing process within 1 mm of the printhead.

Tensile stress in selective laser melted (SLM) stainless steel 316 (SS316) bars was studied with neutron imaging methods for measurement of attenuation, scattering, and diffraction. The hypotheses for stress failure includes modifications to both the grain structure and residual porosity. Neutron Bragg edge imaging showed a change in crystallographic structure and/or texture at a pre-existing fracture, but did not provide evidence for presumptive crack formation. A Talbot-Lau grating-based neutron interferometer yielded better than 100 μm spatial resolution for the attenuation images and was tuned to an autocorrelation scattering length of 1.97 μm for the dark-field (scattering) images. The interferometry imaging was performed with samples parallel and perpendicular to the linear grating, allowing assessment of scattering along and perpendicular to the additive manufacturing build direction. In the 3D tomography dark-field volume of a tensile stressed bar, features were observed that suggested possible sites of crack formation. The features were quantified with line probes and found to be reproducible over three tomography experiments. After imaging, the half-stressed bar was pulled to failure; the fracture point is correlated with a feature in the line probe having enhanced neutron scattering. Neutron interferometry, particularly the dark-field imaging modality, emerges as a powerful non-destructive method for detecting early crack formation in additive manufactured components.

Whole body computed tomography has become standard practice in many centres in the management of severely injured trauma patients, however, the evidence for it's diagnostic accuracy is limited.To assess the sensitivity of whole body CT in major trauma.Retrospective review of all patients with injury severity score (ISS) 15 presenting with blunt trauma to a UK Major Trauma Centre between May 2012 and April 2014. Injuries were classified as per ISS score-1 = head and neck 2 = face 3 = chest 4 = abdomen. The authors reviewed patient's electronic charts, radiological results; interventional procedure records, discharge letters and outpatient follow up documentation and referenced this with Trauma Audit and Research Network data.407 patients with ISS 15 presented to the Trauma centre during May 2012 and April 2014. Of these, 337 (82.8%) had a whole body CT scan. 246 pts were male, 91 were female. 74 (21.9%) were due to a fall from 2 m, 41 (12.2%) due to a fall from 2 m, 208 (61.7%) were due to motor vehicle crashes, 1 (0.3%) due to a blast injury, 5 (1.5%) due to blows, and 8 (2.4%) due to crush injuries. Sensitivity for Region 1 was 0.98, Region 2 = 0.98, Region 3 = 0.98 and Region 4 was 0.95. Overall sensitivity was 0.98. 15 injuries (2.4%) were not identified on initial CT (false -ve). These injuries were: colonic perforation = 1, splenic contusion = 1, pneumothorax = 1, liver laceration = 1, intracranial haemorrhage = 1, cerebral contusions = 1, spinal injuries = 7, canal haemorrhage = 1, maxilla fracture = 1.These results show that whole body CT in trauma has a high sensitivity and a low rate of missed injuries (2.4%). However, our study only evaluated a subgroup of patients with ISS 15 and further work is required to assess the use of this investigation for all major trauma patients.

Fatigue in selective laser melted (SLM) and conventionally manufactured stainless steel (SS) 316 dogbones was studied with neutron imaging methods for attenuation, diffraction, and scattering. Neutron attenuation tomography and Bragg edge imaging did not reveal crack formation. Conversely, to efficiently detect the microcrack evolution, two methods of grating-based neutron interferometry, Talbot-Lau and far-field, were employed. Both interferometry methods detect early crack formation via the dark-field (scattering) images, especially for porous microstructures in the range of 0.6 μm to 2 μm. The dark-field image combines sensitivity to micrometer-sized scattering centers at crack formation with sub-millimeter imaging resolution. The crack formation observed with neutron interferometry dark-field was validated post-imaging with additional fatigue cycles to fracture. Further inspection was performed by scanning electron microscopy (SEM) and optical photography. In the two fatigued dogbones, SLM and conventional crack formation was identified to within 1 mm. Keywords: Additive manufacturing, Neutron interferometry, Bragg edge spectroscopy, Fatigue

This article presents a novel quasi in-situ analysis, which allowed for examining the same microstructural area before and after irradiation, in two distinct facilities. One facility is used for the irradiation, and one for the energy dispersive X-ray spectroscopy (EDX) in a transmission electron microscope (TEM). The material studied is an austenitic oxide dispersion strengthened (ODS) stainless steel, modeled after commercial grade 310 L (25Cr 20Ni 2Mo-0.02C-0.4N-0.35Y2O3-0.5Ti-bal.Fe), which is synthesized from a powder metallurgy fabrication route using hot isostatic pressing. ODS materials are suitable for applications in: structural, highly corrosive, nuclear, and electromagnetic field environments. In fact, new generation fusion systems represent all four of these demands at the same time. The 310-ODS material is irradiated to ∼1.5dpa at 520OC with 1 MeV Kr2+ 7.5 × 1014 ions cm−2 (∼1.25 × 10−3 dpa/s). Quasi in-situ EDX line scans are presented, focusing on the interactions of: Fe, Cr, Ni, Y, Ti, and O. The examined particles are two Ti-rich structures, which present themselves as non-stoichiometric oxides (>200 nm) embedded within the iron matrix. The Y/Ti at% ratios in both observed particles decreased slightly from 0.34 ± 0.07 and 0.28 ± 0.04, to 0.26 ± 0.08 and 0.20 ± 0.06 respectively, suggesting a dissolution mechanism has initiated under this irradiation condition. It is often a question of dissolution vs. amorphization in these materials. Included is a detailed discussion of these two mechanisms as a function of temperature, fluence, and irradiating energy, with contrast to the current literature. Furthermore, attached is a data-in-brief (DiB), which includes the EDX spectrum and raw data captured from the experiment.

A high-resolution neutron tomography system and a grating-based interferometer are used to explore electron beam-melted titanium test objects. The high-resolution neutron tomography system (attenuation-based imaging) has a pixel size of 6.4 µm, appropriate for detecting voids near 25 µm over a (1.5 cm)3 volume. The neutron interferometer provides dark-field (small-angle scattering) images with a pixel size of 30 µm. Moreover, the interferometer can be tuned to a scattering length, in this case, 1.97 µm, with a field-of-view of (6 cm)3. The combination of high-resolution imaging with grating-based interferometry provides a way for nondestructive testing of defective titanium samples. A chimney-like pore structure was discovered in the attenuation and dark-field images along one face of an electron beam-melted (EBM) Ti-6Al-4V cube. Tomographic reconstructions of the titanium samples are utilized as a source for a binary volume and for skeletonization of the pores. The dark-field volume shows features with dimensions near and smaller than the interferometer auto-correlation scattering length.

It is more than 20 years since the term ‘Damage control’ was introduced to describe an emerging surgical strategy of abbreviated laparotomy for exsanguinating trauma patients. This strategy of temporisation and prioritisation of physiological recovery over completeness of anatomical repair was associated with improved survival in a subset of patients with combined major vascular and multiple visceral injuries. The ensuing years saw the rapid adoption of these principles as standard of care for massively injured and physiologically exhausted patients. Resuscitation of severely injured patients has changed significantly in the last decade with the emergence of a new resuscitation paradigm termed ‘damage control resuscitation’. Originating in combat support hospitals, damage control resuscitation emphasises the primacy of haemorrhage control while directly targeting the ‘lethal triad’ of coagulopathy, acidosis, and hypothermia. Integral to damage control resuscitation is the appropriate application of damage control surgery and together they constitute the modern damage control paradigm. This review aims to discuss the modern application of damage control resuscitation and damage control surgery and to review the evidence supporting its constituent components, as well as considering deficiencies in current knowledge and areas for future research.

Electrothermal vaporization (ETV) coupled to inductively coupled plasma optical emission spectrometry (ICPOES) was applied to the direct analysis of austenitic stainless steel powders using external calibration with increasing amounts of urban particulate matter (NIST 1648a) certified reference material. The method was first validated through the analysis of a reference material of free cutting steel, BCS 152/3, which was also analysed, following digestion in aqua regia, by ICPOES with external calibration using matrix-matched standard solutions. A four-step heating program, where the 30 s vaporization step was not ramped and followed a cooling step after pyrolysis, was used along with hemi-spherical graphite boats and trifluoromethane (CHF3, freon R-23) reaction gas, which resulted in sharp analyte signal peaks. Internal standardization with an argon emission line (415.859 nm) was applied throughout to compensate for sample loading effects on the plasma, improve the signal-to-background ratio and extend the linear dynamic range. Quantification limits ranged from 0.02 (Cd) to 200 (Si) μg g−1 in the solid using 5 mg aliquots, and are one or two orders of magnitude lower than those obtained by ICPOES with nebulization for several elements. The proposed method allowed determination of Al, Cd, Ce, Co, Cu, Mn, Pb, S, Si, Ti, V and Zn at levels in the 10 μg g−1 to 0.4% (m m−1) range, in agreement with results obtained by ICPOES following digestion. The method is suitable for alloy quality control, as it drastically reduces analysis time and cost by eliminating the acid digestion step altogether, which is quite attractive for industrial applications.

A novel neutron far field interferometer is explored for sub-micron porosity detection in laser sintered stainless steel alloy 316 (SS316) test objects. The results shown are images and volumes of the first quantitative neutron dark-field tomography at various autocorrelation lengths, ξ . In this preliminary work, the beam defining slits were adjusted to an uncalibrated opening of 0.5 mm horizontal and 5 cm vertical; the images are blurred along the vertical direction. In spite of the blurred attenuation images, the dark-field images reveal structural information at the micron-scale. The topics explored include: the accessible size range of defects, potentially 338 nm to 4.5 μ m, that can be imaged with the small angle scattering images; the spatial resolution of the attenuation image; the maximum sample dimensions compatible with interferometry optics and neutron attenuation; the procedure for reduction of the raw interferogram images into attenuation, differential phase contrast, and small angle scattering (dark-field) images; and the role of neutron far field interferometry in additive manufacturing to assess sub-micron porosity.

Neutrons uniquely probe matter since the interaction is primarily mediated through the strong nuclear force. Neutron imaging uses this complementarity to create unique views of systems. For batteries, neutrons strongly interact with hydrogen and lithium, so that conventional neutron imaging readily measures the change in either electrolyte concentrations or ion migration in the case of lithium-ion batteries. A novel imaging mode, neutron dark field imaging, extends the capability of neutron imaging to enable one to measure the microstructure, that is length scales from the nm to µm [1]. The dark field is a measure of the pair correlation function, which is linked to conventional small angle scattering through the Hankel transform [2]. Thus, neutron dark field images of lithium-ion batteries can provide spatially resolved measurements (with resolution ~100 µm) of the particle distribution along the path of the neutron beam. Further, dark-field images are not strictly limited to thin sections as is typical of small angle scattering, and one can form tomographic dark-field images. The dark-field image is the change in the visibility (or amplitude) of a moiré pattern with period Pd. The dark-field probes the pair correlation function at the correlation length, ξ, related to Pd, the wavelength of the radiation, λ, and sample-detector separation, Z by ξ = λ Z / Pd [3]. To probe a broad range of correlation lengths, we formed our neutron dark field images with a neutron far field interferometer [4]. The period of the moiré pattern formed by this interferometer is tuned by changing the distance, D, between two phase modulating gratings, where Pd is inversely proportional to D. We applied neutron dark imaging to commercial lithium-ion batteries with different capacities of stored energy. Further, batteries from each capacity were subjected to wear, with 1790 cycles, labeled as worn, 125 cycles as slightly worn, and the battery with 1 charge/discharge cycle is labeled fresh. We acquired neutron dark field images, probing length scales from 100 nm to 3 µm with the batteries in both the fully charged and fully discharged states. As shown in Figure 1, we observe a more-or-less uniform dark field signal across the fresh battery in both charge states. This is contrasted with the worn batteries, which show clear inhomogeneities in the dark field signal, which indicates that the underlying electrode structures have changed in a non-uniform fashion. Our use of commercial batteries limits further quantitative analysis. Further details of the measurement process and the potential to acquire tomographic reconstructions of the microstructure will be presented. Figure 1: Neutron dark-field images at two autocorrelation lengths, xi, for three 43 mAh batteries subjected to different levels of cycling and states of charge. References [1] M. Strobl, “General solution for quantitative dark-field contrast imaging with grating interferometers,” Sci. Rep., 4, art. no. 7243, 2014. [2] R. Andersson, L. F. van Heijkamp, I. M. de Schepper, and W. G. Bouwman , “Analysis of spin-echo small-angle neutron scattering measurements,” J. Appl. Crystallogr., 41(5), 868–885, 2008. [3] H. Wen, E. E. Bennett, M. M. Hegedus, and S. C. Carroll, “Spatial Harmonic Imaging of X-ray Scattering—Initial Results,” IEEE Trans. Med. Imaging, 27(8), 997–1002, 2008. [4] D. A. Pushin, D. Sarenac, D. S. Hussey, H. Miao, M. Arif, D. G. Cory, M. G. Huber, D. L. Jacobson, J. M. LaManna, J. D. Parker, T. Shinohara, W. Ueno, and H. Wen, "Far-field interference of a neutron white beam and the applications to noninvasive phase-contrast imaging," Phys. Rev. A, 95(4), art. no. 043637, 2017. Figure 1

The third stage ofdamage control (DC III) is a critical phase of thepatient’s care. Following unpacking and restorationof gastrointestinal continuity, the final step of DC IIIis closure of the abdominal wall. Frequently, this isnotpossibleasaresultofcontinuedboweledemaorretroperitoneal hematoma. In these patients theabdomen has to be managed open, eventually fol-lowedbyeitherdelayedclosureortheplacementofan absorbable mesh and subsequent delayed skingrafting. Even with meticulous care and dailyabdominal washouts, the incidence of fistula forma-tion during this process is significant.

Twenty-three thousand doctors in the UK have undertaken The Advanced Trauma Life Support Course for doctors over the past 12 years. The course was never designed to provide anything more than a framework within which inexperienced doctors could safely manage multiple injured patients until expert help arrived. Its critics will say that the course is didactic and its treatment protocols are not always up to date. Since its inception in 1976 in Nebraska it has undergone constant revision and the seventh edition of the course will appear in 2002. With each revision, evidence for new methods of management for the trauma victims are reviewed; some of these are discussed in this paper.

Objective: To assess the effectiveness of an educational symposium designed to improve compliance with universal barrier precautions by the use of video analysis of resuscitations. Design: Prospective single blind analysis of data. Setting: Hospital Trauma Unit, Johannesburg, South Africa. Subjects: 100 severely injured patients who presented to the emergency room, divided into two study periods. Interventions: An educational symposium held between the study periods, which focused on universal barrier precautions and the risk of occupational transmission of HIV. Main Outcome Measures: Compliance with items of universal precautions; mechanism; Injury Severity Score and Revised Trauma Score. Results: There was a significant improvement in compliance from 48% to 74% after the symposium (p = 0.007), with specific improvement in the wearing of masks and visors. Initially there was poor compliance with universal precautions in severely injured patients, which significantly improved to 83% compliance (p = 0.0004). Conclusion: Video analysis of resuscitations is an effective audit and educational tool that allows analysis of compliance with protocol. The education symposium was effective in altering attitudes and behaviour towards universal barrier precautions.

The management of blunt abdominal injury (BAI) has undergone quite significant changes over recent years. The emphasis is now on the recognition and limitation of the underlying metabolic insult associated with severe abdominal injury. The concepts of damage control and non-operative management while seeming diametrically opposed have both found favour in selected patient groups. The interventional radiologist has opened a new dimension in the control of inaccessible bleeding and is able to contribute to non-operative approaches. The complimentary use of the methods of investigation available for BAI will also improve the accuracy and specificity of diagnosis allowing more appropriate management. Embracing these new concepts of management by all institutions dealing with trauma victims will hopefully reduce the morbidity and mortality of BAI.

There has been a rapid increase in the use of laparoscopy in general surgery over recent years. However in the field of trauma its role has not been defined and its regular use remains limited to a select group of enthusiasts. We present a review of the current literature on laparoscopic surgery in trauma including therapeutic procedures and a brief synopsis of the alternative methods of investigation for abdominal injury, and our interpretation of the current role of laparoscopic surgery in trauma today.

In year 2000, there were approximately 4600 reported firearm injuries in the UK. Most large urban Accident & Emergency Departments can expect to manage at least 5-10 gunshot injuries per year. In the UK, these injuries tend to involve handguns or shotguns (rather than military-style weapons) and occur in inner-city areas, often being gang- or drug-related. The steady increase in the incidence of gun-associated violence in the UK has occurred despite the alteration in gun legislation that was introduced following a multiple shooting incident in Dunblane, UK, in 1996. The UK, however, remains towards the bottom of the ‘league’ of firearm deaths, with a rate of 0.3 per 100,000 population. In comparison, South Africa, with an estimated 8 million weapons in circulation, has a murder rate of 56 per 100,000, and the USA has a value of 10.6. Explosives cause unique injury patterns, devastating multiple wounds, and trauma to many body systems. The recognition, resuscitation and appropriate management of these injuries is vital. A wide range of weapons can be responsible for ballistic-type injuries, including handguns, automatic assault rifles, bombs, mines and fragments. Whilst it is important to ‘treat the wound and not the weapon’, an understanding of ballistics and injury patterns is valuable, as these wounds can be complex and involve multiple body systems.

Damage Control Surgery (DCS) is an operative strategy that sacrifices the completeness of the immediate surgical repair in order to address the physiological consequences of the combined trauma of the injury and surgery. In the past this has been very much focussed on abdominal trauma and the idea of performing an “abbreviated laparotomy.” However the concepts outlined here are applicable to injury beyond the abdomen.1-3

The concept of damage control resuscitation encompasses multiple phases of care: the prehospital and trauma bay resuscitation (DC 0), the initial surgical exploration via laparotomy, thoracotomy, or sternotomy with exsanguination and contamination control (DC I) and further resuscitation within the surgical intensive care unit (DC II). All of this leads up to definitive organ repair and abdominal closure, termed damage control phase III (DC III). Timing of this particular stage is critical as it will likely have the most impact on achieving traditional measures of “successful outcomes” (e.g.- hospital length of stay, surgical site infections, anastomotic leaks, etc.). Prior to transitioning to DC III, the team should ensure that adequate resuscitation and physiological optimization has been achieved; i.e.; normothermic, normal coagulation studies as well as a normal pH and lactate. With focused, aggressive critical care management and resuscitation one may obtain this physiologic state within 24–36 h.1,2

There are no published studies directly addressing the issue of what is an acceptable timeline from point of wounding to surgical intervention within the military context. The proximal threshold has previously been determined by personal opinion, tactical, logistic and practical imperatives rather than by clinical demands. The aimof this paper is to review all relevantmilitary and civilian studies where timelines have been quoted and to reach a number of unambiguous consensus statements to state the perceived ideal upper limits from point of wounding to holistic and realistic surgical care in modern war. An injured casualty should be transferred to an appropriate surgeon in an appropriate facility in as short a time from wounding as practical. It is clear that the best trauma surgery is performed in large, well resourced, well-supplied, airconditioned hospitals. Current advances aimed to stretch timelines from wounding to surgical intervention are exciting and hold potential but remain scientifically unproven and are currently without any firm evidence base. Further critical research is therefore necessary. The effect of pre-hospital haemostatic resuscitation, provided by the enhanced Medical Emergency Response Team (MERTe) on patient outcome and effective timelines is currently unknown and unproven: it does have intuitive medical merit. There is also a very significant moral and morale component. MERTe serves two main functions; reduction in time from point of wounding to advanced / haemostatic resuscitation and provision of in-flight diagnostics. Continuation of in-flight resuscitation then allows physician-led decision making on critically unstable casualties. This allows either an expedited straight move from the HLS direct to the operating theatre or direct transfer to a regional neurosurgical centre. To prevent avoidable death, our unequivocal conclusion is that there must be an upper limit of 2 hours from wounding to surgical intervention (surgical haemorrhage control) for all casualties.

Radio-opaque markers placed over entry and exit wounds, have been used to help evaluate penetrating injuries and provide a permanent record of wound location on plain radiographs. To date there are no published reports of the application of improvised bullet markers in the evaluation of penetrating injuries using computed tomography (CT). We report a series of 4 cases where bullet markers were used in combination with three-dimensional (3D) computerised tomography (CT) to ascertain the path of the bullets and to assess damage to vital structures. We believe that the use of bullet markers in penetrating trauma casualties undergoing CT is valuable in the surgical decision making process and allows planning of surgical approaches.

A 12-year-old boy presented to the field hospital in Afghanistan following a gunshot wound to his right buttock. He was cardiovascularly stable with no abdominal tenderness. Examination revealed a single wound on his right …

This text is part of a set (now in its second edition), providing an illustrated review of normal anatomy and its common variants, examination techniques and practical clinical considerations. This volume concentrates on the abdomen.

Medical facilities in all locations—urban, rural, or austere—need to prepare to receive casualties well before they arrive. In a civilian hospital, this is likely to involve activating the trauma team and notifying other key personnel. In a military field hospital, this preparation will include putting a system in place to remove safely the casualty’s weapons and ammunition (Figure 8-1). Casualties exposed to chemicals or other noxious agents will need decontamination before entering the hospital.

Summary Objective: To determine opportunities for improvement (OI) in the critical care management of severely injured patients in a general adult intensive care unit through a performance improvement (PI) process. Methods: Retrospective review of patient records from intensive care patients who had sustained traumatic injuries, except isolated head injury, over a 1-year period. Three assessors independently audited the notes using performance improvement methodology to determine complications, errors in management and preventability. Complications were included when two or more assessors independently detected the complication. Measurements and results: Records from 90 patients with a diagnosis of ‘trauma’ were reviewed, 14 patients with isolated head injury were excluded. The mean injury severity score was 23 (range 4–43). No complications or errors of management were identified from 41 patients, including ten patients who died. Seventy-two complications were identified in 35 patients including 15 pneumonias, 6 cases of peri-operative hypothermia and 5 recurrent pneumothoraces. Fourteen preventable complications were identified. Conclusions: The PI OI process highlighted specific opportunities for the improvement of critical care management of trauma patients in our unit. These will be addressed through the introduction of formal tertiary surveys and clinical management guidelines addressing hypothermia and management of coagulopathy.