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FULL FRONTAL CAR CRASH TESTS: EMPIRICAL EVIDENCE ABOUT SHAPE OF DECELERATION PULSES
Timothy Paul Hutchinson 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.2
If deceleration is constant in a vehicle crash, deformation of the vehicle is a function of impact speed and impact duration. The ratio of actual deformation to this idealized quantity may be used to summarize the shape and effects of the deceleration pulse. This ratio reflects whether the pulse is front-loaded (acceleration is greater early in the pulse than later), or back-loaded (acceleration is less early in the pulse than later). Further interpretation of the ratio is possible within simple families of pulse shape, such as M. Huang's TESW (Tipped Equivalent Square Wave) model and the triangular pulse. This paper reviews published test results and summaries of datasets. It is found that pulses tend to be back-loaded. However, this conclusion is sensitive to how deformation, speed, and duration are calculated.
Timothy D Paul,Vimalathithan Rathinasabapathy 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.5
Latest technological innovation in the development of compact lower power radios has led to the explosion of Internet of Things. With Wi-Fi, Zigbee and other physical layer protocols offering short coverage area there was a need for a RF protocol that had a larger coverage area with low power consumption. LoRa offers Long Range with lower power consumption. LoRa offers point to point and point to multipoint connections. with Single hop communication in place the need for routing protocols are eliminated. LoRa Wide Area Network stack can accommodate thousands of nodes under a single LoRa gateway with a single hop communication between the end nodes and LoRaWAN gateway. This paper takes an experimental approach to analyze the basic physical layer parameters of LoRa and the practical coverage offered by a LoRaWAN under highly dense urban conditions with variable topography. The insights gained from the practical deployment of the LoRaWAN network, and the subsequent performance analysis is used to design a novel public utility monitoring platform. The second half of the papers is designing a robust platform to integrate both existing wired sensor water meters, current and future generation wireless water meters. The Common Automated Metering Platform is designed to integrate both wired sensors and wireless (LoRaWAN and Wi-Fi) supported water meters. This integrated platform reduces the number of nodes under each LoRaWAN gateway and thus improves the scalability of the network. This architecture is currently designed to accommodate one utility application but can be modified to integrate multi-utility applications.
Yates, Timothy J.V.,Thomas, John Meurig,Fernandez, Jose-Jesus,Terasaki, Osamu,Ryoo, Ryong,Midgley, Paul A. Elsevier 2006 Chemical physics letters Vol.418 No.4
<P><B>Abstract</B></P><P>High-angle annular dark-field scanning transmission electron tomography has been used to reveal the three-dimensional lattice structure of the mesoporous silica MCM-48. The incoherent nature of the dark-field signal leads to directly interpretable images and three-dimensional tomographic reconstructions. The ability to manipulate the three-dimensional reconstruction allows the structure to be visualised at any orientation, revealing detail in projection or as slices not hitherto seen by direct imaging techniques.</P>
A Review of Finite Element Modeling for Anterior Cervical Discectomy and Fusion
Lin Maohua,Paul Rudy,Dhar Utpal Kanti,Doulgeris James,O’Connor Timothy E.,Tsai Chi-Tay,Vrionis Frank D. 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.5
The cervical spine poses many complex challenges that require complex solutions. Anterior cervical discectomy and fusion (ACDF) has been one such technique often employed to address such issues. In order to address the problems with ACDF and assess the modifications that have been made to the technique over time, finite element analyses (FEA) have proven to be an effective tool. The variations of cervical spine FEA models that have been produced over the past couple of decades, particularly more recent representations of more complex geometries, have not yet been identified and characterized in any literature. Our objective was to present material property models and cervical spine models for various simulation purposes. The outlining and refinement of the FEA process will yield more reliable outcomes and provide a stable basis for the modeling protocols of the cervical spine.
Lin Maohua,Paul Rudy,Shapiro Stephen Z.,Doulgeris James,O’Connor Timothy E.,Tsai Chi-Tay,Vrionis Frank D. 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.5
Study Design: This study compares four cervical endplate removal procedures, validated by finite element models.Purpose: To characterize the effect of biomechanical strength and increased contact area on the maximum von Mises stress, migration, and subsidence between the cancellous bone, endplate, and implanted cage.Overview of Literature: Anterior cervical discectomy and fusion (ACDF) has been widely used for treating patients with degenerative spondylosis. However, no direct correlations have been drawn that incorporate the impact of the contact area between the cage and the vertebra/endplate.Methods: Model 1 (M1) was an intact C2C6 model with a 0.5 mm endplate. In model 2 (M2), a cage was implanted after removal of the C4–C5 and C5–C6 discs with preservation of the osseous endplate. In model 3 (M3), 1 mm of the osseous endplate was removed at the upper endplate. Model 4 (M4) resembles M3, except that 3 mm of the osseous endplate was removed.Results: The range of motion (ROM) at C2C6 in the M2–M4 models was reduced by at least 9º compared to the M1 model. The von Mises stress results in the C2C3 and C3C4 interbody discs were significantly smaller in the M1 model and slightly increased in the M2–M3 and M3–M4 models. Migration and subsidence decreased from the M2–M3 model, whereas further endplate removal increased the migration and subsidence as shown in the transition from M3 to M4.Conclusions: The M3 model had the least subsidence and migration. The ROM was higher in the M3 model than the M2 and M4 models. Endplate preparation created small stress differences in the healthy intervertebral discs above the ACDF site. A 1 mm embedding depth created the best balance of mechanical strength and contact area, resulting in the most favorable stability of the construct.
Pravesh S. Gadjradj,Timothy C. Chin-See-Chong,Daphne Donk,Paul Depauw,Maurits W. van Tulder,Biswadjiet S. Harhangi 대한척추신경외과학회 2021 Neurospine Vol.18 No.4
Objective: To perform the psychometric validation of the Dutch version of the Core Outcome Measures Index (COMI) for the neck. Methods: A total of 178 patients, who had an indication for surgery due to degenerative cervical spinal disease, were enrolled in the study. They filled in a baseline booklet containing the Dutch version of the COMI-neck, Likert-scales for neck and arm/shoulder pain, the Neck Disability Index (NDI), the EuroQol-5 dimensions (EQ-5D) and the 12-item Short Form health survey (SF-12). Aside from analyzing construct validity using the Spearman correlation test, test-retest reliability, and responsiveness at 3 months were assessed using the intraclass correlation coefficient (ICC) and the receiver-operating characteristic (ROC) curve, respectively. Results: The COMI-neck showed good acceptability with missing data ranging from 0% to 4.5% and some floor/ceiling effects for 3 of the domains at baseline. The COMI-summary score showed good to very good correlation with the EQ5D (ρ=-0.43), the physical component summary of the SF-12 (ρ=-0.47) and the NDI (ρ=0.73). Individual domains showed correlations of -0.28 to 0.85 with the reference questionnaires. Test-retest reliability analysis showed an ICC of 0.91 with a minimal detectable change of 1.7. Responsiveness analysis of the COMI-neck showed an area under 0.79 under the ROC-curve. The standardized response mean for a good outcome was 1.24 and for a poor outcome 0.37. Conclusion: The current study shows that the Dutch version of the COMI-neck is a valid, reliable and responsive Patient-Reported Outcome Measure, among patients undergoing surgery for degenerative cervical spinal disorders.
General principles and overview of vascular contrast-enhanced ultrasonography
Vasileios Rafailidis,Dean Y. Huang,Gibran Timothy Yusuf,Paul S. Sidhu 대한초음파의학회 2020 ULTRASONOGRAPHY Vol.39 No.1
Ultrasonography (US) is the first-line modality for the evaluation of vascular pathology. Although well-established for many diseases, US has inherent limitations that can occasionally hinder an accurate diagnosis. The value of US was improved by the introduction of microbubbles as ultrasonographic contrast agents (UCAs) and the emergence of contrast-enhanced ultrasonography (CEUS), following the introduction of second-generation UCAs and the emergence of modern contrast-specific techniques. CEUS offers valuable information about vascular disease, both on a macrovascular and a microvascular level, with well-established applications for carotid disease, post-interventional follow-up of abdominal aortic aneurysms, and the assessment of portal vein thrombosis. The purpose of this review is to discuss the principles of CEUS and to present an overview of its vascular applications.