Browse Topic: Computed tomography (CT)
Ongoing research in simulated vehicle crash environments utilizes postmortem human subjects (PMHS) as the closest approximation to live human response. Lumbar spine injuries are common in vehicle crashes, necessitating accurate assessment methods of lumbar loads. This study evaluates the effectiveness of lumbar intervertebral disc (IVD) pressure sensors in detecting various loading conditions on component PMHS lumbar spines, aiming to develop a reliable insertion method and assess sensor performance under different loading scenarios. The pressure sensor insertion method development involved selecting a suitable sensor, using a customized needle-insertion technique, and precisely placing sensors into the center of lumbar IVDs. Computed tomography (CT) scans were utilized to determine insertion depth and location, ensuring minimal tissue disruption during sensor insertion. Tests were conducted on PMHS lumbar spines using a robotic test system for controlled loading in flexion
Magnetic resonance imaging (MRI) and computed tomography (CT) scanning have improved and extended millions of patient lives by giving medical professionals high quality images of injures, tumors, infections, internal bruises, and other areas of concern within patient bodies. While the value of these systems is undeniable, their size, capital cost, and per-use cost limit their availability in certain applications.
With the rapid development of electric vehicles (EVs), lithium-ion batteries (LIBs) with high energy and power density have been widely applied as the power producer of EVs. However, the range of EVs has been criticized. To meet consumer demand for high power and long driving distances, the energy and power density of LIBs are getting higher and higher. However, LIBs with higher energy density are more prone to catastrophic thermal runaway (TR). In recent years, EV accidents due to TR of LIBs have been frequently reported, which makes consumers lose confidence in EVs. To solve the problem, we must understand the mechanism of LIBs TR, thereby reducing the likelihood of TR in EVs. However, the induction mechanism of LIB TR induced by mechanical abuse is sophisticated. This paper focuses on recent advances in the study of thermal TR characteristics of batteries caused by mechanical abuse, including bending, collisions, and penetration. The impact of various mechanical abuses on the TR
In this study, a parametric thoracic spine (T-spine) model was developed to account for morphological variations among the adult population. A total of 84 CT scans were collected, and the subjects were evenly distributed among age groups and both sexes. CT segmentation, landmarking, and mesh morphing were performed to map a template mesh onto the T-spine vertebrae for each sampled subject. Generalized procrustes analysis (GPA), principal component analysis (PCA), and linear regression analysis were then performed to investigate the morphological variations and develop prediction models. A total of 13 statistical models, including 12 T-spine vertebrae and a spinal curvature model, were combined to predict a full T-spine 3D geometry with any combination of age, sex, stature, and body mass index (BMI). A leave-one-out root mean square error (RMSE) analysis was conducted for each node of the mesh predicted by the statistical model for every T-spine vertebra. Most of the RMSEs were less
Lithium-ion batteries now in widespread use for everything from mobile electronics to electric vehicles rely on a liquid electrolyte to carry ions back and forth between electrodes within the battery during charge and discharge cycles. The liquid uniformly coats the electrodes, allowing free movement of the ions.
Automation can produce large quantities of product quickly, but ensuring end-part quality is a critical challenge. Visual, manual, or periodic sampling methodologies can be imprecise, slow, or come in too late to trigger a timely line stoppage once a manufacturing error has occurred, resulting in a high proportion of discarded parts.
In the circuit board industry, an increasing number of parts and boards are proving to be difficult to inspect with automated optical inspection (AOI) because the solder is invisible. Furthermore, high-quality requirements such as bonding strength of the automobile industry and full surface inspection of the solder are increasing. To address these needs, Omron has introduced new technology for accomplishing inspections within the required inline take time (the rate at which a product must be completed to meet customer demand). This has been one of the most challenging requirements for computed tomography (CT) X-ray automatic inspection equipment. For continuous imaging technology, highly accurate positioning control and high-speed image sensing are required.
In order to study the influence of lubricant ash on the performance of the CN6 after-treatment system, especially the catalyst characteristics of Coated Gasoline Particulate Filter (CGPF), the system was rapidly aged on the engine bench by blending combustion method, and the ash content of 60g represented the endurance of 200kkm CGPF. The effects of CGPF with different endurance mileage on particulate matter emission, gas light-off temperature and engine performance of a Gasoline Direct Injection (GDI) vehicle were studied on the engine bench, chassis dynamometer and real-road tests. Finally, the ash distribution was analyzed by computed tomography (CT). The results showed that the vehicle equipped with CGPF could meet the requirements of CN6 particulate and gas emission limits under both worldwide harmonized light vehicles test cycle (WLTC) and real driving emission (RDE) tests. With the ash accumulation in the CGPF, the filtration efficiency of CGPF for the particulate number (PN
This study employed a diesel particulate generator (DPG), with an installed engine oil injector for soot and ash accumulation in a diesel particulate filter (DPF). Ash was generated by engine oil injection into the diesel burner flame. The amount of soot accumulation per loading varied from 0.5 g/L to 8 g/L while ash accumulation amount per loading was maintained at 0.5 g/L. Initially, ash accumulation distribution in the DPF was visualized using X-ray computed tomography (CT). It was revealed that the form of ash accumulation changed depending on the amount of soot accumulation before active regeneration, i.e., a large amount of soot accumulation resulted in plug ash, whereas a small amount of soot accumulation resulted in wall ash. To clarify ash accumulation mechanisms, soot and ash transport behavior in DPF during active regeneration process was directly observed using a high-speed camera through an optically accessible D-shaped cut DPF covered with a quartz glass plate. From the
Catalytic and non-catalytic engine aftertreatment components, such as the diesel oxidation catalyst (DOC), selective catalytic reduction on filter (SCRF), the gasoline particulate filter (GPF) and the diesel particulate filter (DPF) are complex, multifunctional emissions control technologies that are robustly designed for extended use in harsh automotive exhaust environments. Over the useful component lifetime, lubricant-derived inorganic and incombustible ash accumulates in and/or on the surface of the aforementioned aftertreatment components, resulting in degraded performance and other potential problems. In order to better understand effects of ash in such components, a multiscale analytical approach is necessary, requiring a variety of experimental tools. This paper will briefly present a decade of analytical experience at the Sloan Automotive Laboratory at the Massachusetts Institute of Technology and at Kymanetics, Inc., specific to the fundamental understanding of the
Crash safety researchers have an increased concern regarding the decreased thoracic deflection and the contributing injury causation factors among the elderly population. Sternum fractures are categorized as moderate severity injuries, but can have long term effects depending on the fragility and frailty of the occupant. Current research has provided detail on rib morphology, but very little information on sternum morphology, sternum fracture locations, and mechanisms of injury. The objective of this study is two-fold (1) quantify sternum morphology and (2) document sternum fracture locations using computed tomography (CT) scans and crash data. Thoracic CT scans from the University of Michigan Hospital database were used to measure thoracic depth, manubriosternal joint, sternum thickness and bone density. The sternum fracture locations and descriptions were extracted from 63 International Center for Automotive Medicine (ICAM) crash cases, of which 22 cases had corresponding CT scans
In recent years along with stringent the regulations, vehicles equipped with gasoline particulate filter (GPF) have started to launch. Compared to bare GPF, coated GPF (cGPF) requires not only PN filtration efficiency, low pressure drop, but also purification performance. In the wall flow type cGPF having a complicated the pore shape, the pore structure further irregularly changes depending on the coated state of the catalyst, so it is difficult to understand the matter of in-wall. In order to advance of cGPF function, it was researched that revealing the relevance between pore structure change in the wall and GPF function. Therefore, to understand the catalyst coated state difference, cGPF of several coating methods were prepared, and their properties were evaluated by various analyses, and performance was tested. First of all, as a result of Mercury porosimetry analysis revealed that the pore diameter of the filter wall of GPF is a key factor for the pressure drop and the Particulate
Recent legislation enacted for the European Union (EU) and the United States calls for a substantial reduction in particulate mass (and number in the EU) emissions from gasoline spark-ignited vehicles. The most prominent technology being evaluated to reduce particulate emissions from a gasoline vehicle is a wall flow filter known as a gasoline particulate filter (GPF). Similar in nature to a diesel particulate filter (DPF), the GPF will trap and store particulate emissions from the engine, and oxidize said particulate with frequent regeneration events. The GPF will also collect ash particles in the wall flow substrate, which are metallic components that cannot be oxidized into gaseous components. Due to high temperature operation and frequent regeneration of the GPF, the impact of ash on the GPF has the potential to be substantially different from the impact of ash on the DPF. Therefore, traditional accelerated ash loading methods used for DPFs may not be applicable to the GPF
The purpose of this study was to use detailed medical information to evaluate thoracic injuries in elderly patients in real world frontal crashes. In this study, we used analytic morphomics to predict the effect of torso geometry on rib fracture, a major source of injury for the elderly. Analytic morphomics extracts body features from computed tomography (CT) scans of patients in a semi-automated fashion. Thoracic injuries were examined in front row occupants involved in frontal crashes from the International Center for Automotive Medicine (ICAM) database. Among these occupants, two age groups (age < 60 yr. [Nonelderly] and age ≥ 60 yr. [Elderly]) who suffered severe thoracic injury were analyzed. Regression analyses were conducted to investigate injury outcomes using variables for vehicle, demographics, and morphomics. Compared to the nonelderly group, the elderly group sustained more rib fractures. Logistic regression models were fitted with different configurations of variables
Staying competitive calls for medical equipment OEMs to constantly keep pace with the speed of innovation. Better medical treatment and care can be achieved with fast, accurate results from advanced imaging applications such as CT scanning and MRI that process and analyze large amounts of data, requiring developers to build devices that deliver ever-increasing computing performance. Supporting this demand, high-performance embedded computing platforms that use the latest faster and more efficient processors are essential in helping OEMs keep up with these enhanced performance requirements.
Surgeons can swab a patient’s exposed liver lightly on the surface with a special stylus, capturing the shape of the organ during surgery, and a computer can match that image with the CT scan on a screen. This GPS-like ability is far better than guessing where the tumor and vessels are by feeling for them, but even this road map can be off by centimeters and leaves surgeons guessing.
The salient features of modern gasoline direct injection include cavitation, flash boiling, and plume/plume interaction, depending on the operating conditions. These complex phenomena make the prediction of the spray behavior particularly difficult. The present investigation combines mass-based experimental diagnostics with an advanced, in-house modeling capability in order to provide a multi-faceted study of the Engine Combustion Network’s Spray G injector. First, x-ray tomography is used to distinguish the actual injector geometry from the nominal geometry used in past works. The actual geometry is used as the basis of multidimensional CFD simulations which are compared to x-ray radiography measurements for validation under cold conditions. The influence of nozzle diameter and corner radius are of particular interest. Next, the model is used to simulate flash-boiling conditions, in order to understand how the cold flow behavior corresponds to flashing performance.
This work investigates the injection processes of an eight-hole direct-injection gasoline injector from the Engine Combustion Network (ECN) effort on gasoline sprays (Spray G). Experiments are performed at identical operating conditions by multiple institutions using standardized procedures to provide high-quality target datasets for CFD spray modeling improvement. The initial conditions set by the ECN gasoline spray community (Spray G: Ambient temperature: 573 K, ambient density: 3.5 kg/m3 (∼6 bar), fuel: iso-octane, and injection pressure: 200 bar) are examined along with additional conditions to extend the dataset covering a broader operating range. Two institutes evaluated the liquid and vapor penetration characteristics of a particular 8-hole, 80° full-angle, Spray G injector (injector #28) using Mie scattering (liquid) and schlieren (vapor). Diffused back-illumination (DBI) imaging, which is the ECN standard liquid length diagnostic, was also used to provide a reference for the
The software for NASA’s Northstar Systems computed tomography (CT) and Picometrix Terahertz CT systems do not have the ability to unwrap and reslice cylindrical CT data to allow top-to-bottom, 2D sheet views of the data. Therefore, it is difficult to size flaws laterally (although viewing slices in the slice view plane allows sizing flaws in the depth [exterior-to-interior] direction). The unwrapped and resliced view would greatly facilitate inspection assessments.
While metal fiber filters have successfully shown a high degree of particle retention functionality for various sizes of diesel engines with a low pressure drop and a relatively high filtration efficiency, little is known about the effects of lubricant-derived ash on the fiber filter systems. Sintered metal fiber filters (SMF-DPF), when used downstream from a diesel engine, effectively trap and oxidize diesel particulate matter via an electrically heated regeneration process where a specific voltage and current are applied to the sintered alloy fibers. In this manner the filter media essentially acts as a resistive heater to generate temperatures high enough to oxidize the carbonaceous particulate matter, which is typically in excess of 600°C. The regeneration process does not require additional fuel, such as in the case of active regeneration in conventional/ceramic wall-flow diesel particulate filters (DPF), since the energy required for regeneration typically comes from another
Long fiber reinforced plastics (LFRP) have exhibited superior mechanical performance and outstanding design flexibility, bringing them with increasing popularity in the automotive structural design. Due to the injection molding process, the distribution of long fibers varies at different locations throughout the part, resulting in anisotropic and non-uniform mechanical properties of the final LFRP parts. Images from X-ray CT scan of the materials show that local volume fraction of the long fibers tends to be higher at core than at skin layer. Also fibers are bundled and tangled to form clusters. Most of the current micromechanical material models used for LFRP are extended from those for short fibers without adequate validation. The effect of the complexity of long fibers on the material properties is not appropriately considered. Thus, modeling of these materials is lagging behind the material manufacturing and design development, which in turn limits their further development. In
In this paper the investigation with X-ray Tomography on the structure of a gasoline spray from a GDI injector for automotive applications based on polycapillary optics is reported. Table-top experiment using a microfocus Cu Kα X-ray source for radiography and tomography has been used in combination with a polycapillary halflens and a CCD detector. The GDI injector is inserted in a high-pressure rotating device actuated with angular steps Δθ = 1° at the injection pressure of 8.0 MPa. The sinogram reconstruction of the jets by slices permits a 360° spray access to the fuel downstream the nozzle tip. A spatial distribution of the fuel is reported along the direction of six jets giving a measure of the droplet concentration in a circle of 16 mm2 below the nozzle tip at atmospheric backpressure and ambient temperature.
In this study, the orifice inlet rounding radii of four diesel nozzles with different hydro erosive grinding time were measured based on the x-ray CT scan technology provided by Shanghai Synchrotron Radiation Facility (SSRF), and a wide parametrical study of the spray macroscopic behavior in the first 18 mm from the nozzle tip have been carried out with high speed camera. And then the influence of orifice inlet rounding radius on the spray behavior in the near-nozzle field was thoroughly investigated. The investigation results show that: the mean values of orifice inlet rounding radii of different nozzles are measured to be on the order of 21.5-56.8 μm. Although the spray tip penetrations of different nozzles tend to increase with the hydro erosive grinding time through statistical analyzing method, the variations of penetration from nozzles are less than 15% according to different hydro erosive grinding timing. For the spray cone angle in the near-nozzle field, the same maximum for
In this paper, a microstructure-based three-dimensional (3D) finite element modeling method is adopted to investigate the effects of porosity in thin-walled high pressure die-cast (HPDC) magnesium alloys on their ductility. For this purpose, the cross-sections of AM60 casting samples are first examined using optical microscope and X-ray tomography to obtain the general information on the pore distribution features. The experimentally observed pore distribution features are then used to generate a series of synthetic microstructure-based 3D finite element models with different pore volume fractions and pore distribution features. Shear and ductile damage models are adopted in the finite element analyses to induce the fracture by element removal, leading to the prediction of ductility. The results in this study show that the ductility monotonically decreases as the pore volume fraction increases and that the effect of ‘skin region’ on the ductility is noticeable under the condition of
Mercury porosimetry (MP) is one of the analytical methods to measure the porosity and the pore size distribution of porous materials. We have developed a new method of digital mercury porosimetry (DMP) for characterizing the porous structure by simulating the measuring processes of MP without using any mercury. Firstly, the contact angle between the mercury and the substance surfaces is theoretically calculated by quantum chemical molecular dynamics. Secondly, a group of images showing the porous structure is obtained with an X-ray computed tomography scanner, and then a three-dimensional digital model is reconstructed connecting the pores/substances boundaries between each image. Thirdly, mercury intrusion which is a fundamental process of the MP method is digitally simulated. The digital mercury intrudes into pores of the digital model from its circumference with the theoretically calculated contact angle. Both the intruded volume and the corresponding pressure virtually applied to
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