Characterizing the Interaction Among Bullet, Body Armor, and Human and Surrogate Targets

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Weixin Shen ◽  
Yuqing Niu ◽  
Lucy Bykanova ◽  
Peter Laurence ◽  
Norman Link
Keyword(s):  
Energy Absorption ◽  
High Speed ◽  
Target Material ◽  
The Body ◽  
Body Armor ◽  
Second Phase ◽  
Model Calculations ◽  
Ballistic Resistance ◽  
Third Phase ◽  
Protective Effectiveness

This study used a combined experimental and modeling approach to characterize and quantify the interaction among bullet, body armor, and human surrogate targets during the 10–1000 μs range that is crucial to evaluating the protective effectiveness of body armor against blunt injuries. Ballistic tests incorporating high-speed flash X-ray measurements were performed to acquire the deformations of bullets and body armor samples placed against ballistic clay and gelatin targets with images taken between 10 μs and 1 ms of the initial impact. Finite element models (FEMs) of bullet, armor, and gelatin and clay targets were developed with material parameters selected to best fit model calculations to the test measurements. FEMs of bullet and armor interactions were then assembled with a FEM of a human torso and FEMs of clay and gelatin blocks in the shape of a human torso to examine the effects of target material and geometry on the interaction. Test and simulation results revealed three distinct loading phases during the interaction. In the first phase, the bullet was significantly slowed in about 60 μs as it transferred a major portion of its energy into the body armor. In the second phase, fibers inside the armor were pulled toward the point of impact and kept on absorbing energy until about 100 μs after the initial impact when energy absorption reached its peak. In the third phase, the deformation on the armor’s back face continued to grow and energies inside both armor and targets redistributed through wave propagation. The results indicated that armor deformation and energy absorption in the second and third phases were significantly affected by the material properties (density and stiffness) and geometrical characteristics (curvature and gap at the armor-target interface) of the targets. Valid surrogate targets for testing the ballistic resistance of the armor need to account for these factors and produce the same armor deformation and energy absorption as on a human torso until at least about 100 μs (maximum armor energy absorption) or more preferably 300 μs (maximum armor deformation).

Body Armor Technology: A Review of Materials, Construction Techniques and Enhancement of Ballistic Energy Absorption

2012 ◽  
Vol 488-489 ◽  
pp. 806-812 ◽  
Author(s):  
A.R. Azrin Hani ◽  
A. Roslan ◽  
J. Mariatti ◽  
M. Maziah
Keyword(s):  
Energy Absorption ◽  
Impact Velocity ◽  
High Speed ◽  
The Body ◽  
Body Armor ◽  
Current Development ◽  
Projectile Impact ◽  
Dangerous Situation ◽  
Construction Techniques

Body armor is a material to protect body from injury of various kind of high speed projectile impact velocity in combat or other dangerous situation. Researchers were found to actively research and exploring new body armor technology due to the invention of new firearms. Furthermore, they were also competing in developing ballistic panel which is lighter in weight, more flexible and comfort in use, cheaper in cost and manufacturability. This paper reviews the body armor commercial and current development materials, structure and construction techniques involved and related works on enhancing ballistic energy absorption.

Linking Theory to Practice: Predicting Ballistic Performance from Mechanical Properties of Aged Body Armor

2020 ◽  
Vol 125 ◽  
Author(s):  
Amanda L. Forster ◽  
Dennis D. Leber ◽  
Amy Engelbrecht-Wiggans ◽  
Virginie Landais ◽  
Allen Chang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Accelerated Aging ◽  
Test Methods ◽  
The Body ◽  
Body Armor ◽  
Ballistic Limit ◽  
Ballistic Performance ◽  
Validation Data ◽  
Data Set ◽  
Ballistic Resistance

It has long been a goal of the body armor testing community to establish an individualized, scientific-based protocol for predicting the ballistic performance end of life for fielded body armor. A major obstacle in achieving this goal is the test methods used to ascertain ballistic performance, which are destructive in nature and require large sample sizes. In this work, using both the Cunniff and Phoenix-Porwal models, we derived two separate but similar theoretical relationships between the observed degradation in mechanical properties of aged body armor and its decreased ballistic performance. We present two studies used to validate the derived functions. The first correlates the degradation in mechanical properties of fielded body armor to the degradation produced by a laboratory accelerated-aging protocol. The second examines the ballistic resistance and the extracted-yarn mechanical properties of new and laboratory-aged body armor made from poly(p-phenylene-2,6-benzobisoxazole), or PBO, and poly(p-phenylene terephthalamide), or PPTA. We present correlations found between the tensile strengths of yarns extracted from armor and the ballistic limit (V50) when significant degradation of the mechanical properties of the extracted yarns was observed. These studies provided the basis for a validation data set in which we compared the experimentally measured V50 ballistic limit results to the theoretically predicted V50 results. The theoretical estimates were generally shown to provide a conservative prediction of the ballistic performance of the armor. This approach is promising for the development of a tool for fielded armor performance surveillance relying upon mechanical testing of armor coupon samples.

scholarly journals Teknik Pemeriksaan Kedokteran Nuklir Bone Scan di Instalasi Radiologi RSUP Dr. Kariadi Semarang

2021 ◽  
Vol 7 (1) ◽  
pp. 8-14
Author(s):  
Nanik Sudaryatmi ◽  
Siti Masrochah ◽  
Muhammad Erfansyah
Keyword(s):  
Bone Scan ◽  
Malignant Tumors ◽  
Blood Pool ◽  
The Body ◽  
Phase Method ◽  
Benign Tumors ◽  
Second Phase ◽  
Third Phase ◽  
Patient Will ◽  
Total Body

Background: A bone scan or commonly referred to as bone print is nuclear medicine examination using a radioactive substance or radiopharmaceutical that is inserted into the body through intravenous injection which aims to help diagnose abnormalities that occur in the bone. This imaging procedure uses a radiopharmaceutical 99mTc-MDP (methylenediphosphonate) is the most commonly used radiopharmaceutical.Methods: The patient will be injected with this radiopharmaceutical at a dose of 15-20 mCi, through the vein in the hand. Imaging can be done as soon as the radiopharmaceutical is injected or after a while to wait for the radiopharmaceutical to be distributed and absorbed by the bone, about 3-5 hours later. Imaging is done by three-phase method, namely the first phase (Vascular phase), the second phase (Blood Pool phase), and the third phase (Total body phase) l.Results: The bone scan method is an efficient examination because in 1x the imaging can provide a complete picture from the head to the foot. Evaluation of results, under normal conditions the distribution of radioactivity in the bone appears symmetrical.Conclusion: In the process of bone metastasis, it can be seen that typical pathological radioactivity can be multiple (multiple hot spots). Malignant tumors can be distinguished from benign tumors by blood pool examination.

scholarly journals Design and Evaluation of Hybrid Composite Plates for Ballistic Protection: Experimental and Numerical Investigations

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1450
Author(s):  
Farah Alkhatib ◽  
Elsadig Mahdi ◽  
Aamir Dean
Keyword(s):  
Energy Absorption ◽  
Hybrid Composite ◽  
Composite Plates ◽  
Maximum Energy ◽  
Body Armor ◽  
Second Phase ◽  
Finite Element Software ◽  
Ballistic Protection ◽  
Ballistic Test ◽  
Simulation Results

In this paper, hybrid composite plates for ballistic protection were investigated experimentally and numerically, with a target to reduce the weight of currently used body armor inserts and, at the same time, satisfy the requirements of the National Institute of Justice’s (NIJ) ballistic protection standards. The current study has three phases to improve the ballistic plate’s energy absorption capability. The first phase is devoted to studying the effect of the material types, including three different fibers: carbon fiber, date palm fiber, and Kevlar fiber. The second phase is dedicated to studying the effect of hybridization within layers. The two previous phases’ results were analyzed to optimize the material based on the hybrid composite ballistic plate’s maximum energy absorption capability. The commercial finite element software package LS-DYNA was employed for numerical modeling and simulation. The hybrid composite ballistic plate could absorb more impact energy than the non-hybrid Kevlar plate with the same area density from the numerical simulation results. This study provides lighter-weight ballistic inserts with a high protection level, making movement easier for the wearer. The numerical results were verified by comparing results of a plate made of 40 layers of Kevlar with an actual ballistic test. The results indicated that the simulation results were conservative compared to the ballistic test.

Influence of stable iodine on the uptake of the thyroid – model vs. experiment

2001 ◽  
Vol 40 (01) ◽  
pp. 31-37 ◽  
Author(s):  
U. Wellner ◽  
E. Voth ◽  
H. Schicha ◽  
K. Weber
Keyword(s):  
Time Course ◽  
Compartment Model ◽  
The Body ◽  
Iodine Uptake ◽  
Model Calculations ◽  
Physiological Conditions ◽  
Iodine Supply ◽  
Predicted Values ◽  
The Individual ◽  
Stable Iodine

Summary Aim: The influence of physiological and pharmacological amounts of iodine on the uptake of radioiodine in the thyroid was examined in a 4-compartment model. This model allows equations to be derived describing the distribution of tracer iodine as a function of time. The aim of the study was to compare the predictions of the model with experimental data. Methods: Five euthyroid persons received stable iodine (200 μg, 10 mg). 1-123-uptake into the thyroid was measured with the Nal (Tl)-detector of a body counter under physiological conditions and after application of each dose of additional iodine. Actual measurements and predicted values were compared, taking into account the individual iodine supply as estimated from the thyroid uptake under physiological conditions and data from the literature. Results: Thyroid iodine uptake decreased from 80% under physiological conditions to 50% in individuals with very low iodine supply (15 μg/d) (n = 2). The uptake calculated from the model was 36%. Iodine uptake into the thyroid did not decrease in individuals with typical iodine supply, i.e. for Cologne 65-85 μg/d (n = 3). After application of 10 mg of stable iodine, uptake into the thyroid decreased in all individuals to about 5%, in accordance with the model calculations. Conclusion: Comparison of theoretical predictions with the measured values demonstrated that the model tested is well suited for describing the time course of iodine distribution and uptake within the body. It can now be used to study aspects of iodine metabolism relevant to the pharmacological administration of iodine which cannot be investigated experimentally in humans for ethical and technical reasons.

PENERAPAN MODEL QUANTUM LEARNING UNTUK MENINGKATKAN HASIL BELAJAR AUTOCAD SISWA KELAS X TEKNIK PEMESINAN SMK NEGERI 1 STABAT

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Abdul Hasan Saragih
Keyword(s):  
Positive Response ◽  
Phase 1 ◽  
First Grade ◽  
Learning Model ◽  
Second Phase ◽  
Phase 2 ◽  
Phase 3 ◽  
The Third ◽  
Third Phase ◽  
Quantum Learning

This classroom research was conducted on the autocad instructions to the first grade of mechinary class of SMK Negeri 1 Stabat aiming at : (1) improving the student’ archievementon autocad instructional to the student of mechinary architecture class of SMK Negeri 1 Stabat, (2) applying Quantum Learning Model to the students of mechinary class of SMK Negeri 1 Stabat, arising the positive response to autocad subject by applying Quantum Learning Model of the students of mechinary class of SMK Negeri 1 Stabat. The result shows that (1) by applying quantum learning model, the students’ achievement improves significantly. The improvement ofthe achievement of the 34 students is very satisfactory; on the first phase, 27 students passed (70.59%), 10 students failed (29.41%). On the second phase 27 students (79.41%) passed and 7 students (20.59%) failed. On the third phase 30 students (88.24%) passed and 4 students (11.76%) failed. The application of quantum learning model in SMK Negeri 1 Stabat proved satisfying. This was visible from the activeness of the students from phase 1 to 3. The activeness average of the students was 74.31% on phase 1,81.35% on phase 2, and 83.63% on phase 3. (3) The application of the quantum learning model on teaching autocad was very positively welcome by the students of mechinary class of SMK Negeri 1 Stabat. On phase 1 the improvement was 81.53% . It improved to 86.15% on phase 3. Therefore, The improvement ofstudent’ response can be categorized good.

Mixed-Methods Evaluation as Scaffold to the Development of a Mobile Health Application to Support the Prescription of Wheelchairs and Postural Support Devices (Preprint)

2020 ◽  
Author(s):  
Adriana Klein ◽  
Roseli de Deus Lopes ◽  
Rodrigo Suigh
Keyword(s):  
Mixed Methods ◽  
Mobile Health ◽  
Second Phase ◽  
The Third ◽  
Evaluation Approach ◽  
Mixed Methods Evaluation ◽  
Usability Tests ◽  
Third Phase ◽  
Postural Support ◽  
Support Devices

BACKGROUND EasySeating is a mobile health (mHealth) app that supports the prescription of wheelchair and postural support devices (WPSD). It can be used by occupational therapists (OT) and physiotherapists (PT) who prescribe WPSD. The app offers a standardization of the prescription procedure, showing images, metrics and details that guide the prescriber to decide on the best equipment. It was developed with an iterative mixed-methods evaluation approach. Objective: The aim of this study was to investigate the processes involved in the prescription of WPSD and to propose, develop and evaluate a mHealth to support OT and PT prescribers. OBJECTIVE The aim of this study was to investigate the processes involved in the prescription of WPSD and to propose, develop and evaluate a mHealth to support OT and PT prescribers. METHODS This study was divided into three phases and was carried out as an iterative process composed of user consulting/testing (using a mixed-methods evaluation approach), system (re)design and software development. The first phase consisted of the collection of qualitative and quantitative data to map and understand the users requirements and of the development of the first prototype (v1) of the app. This data collection was performed through semi-structured interviews with 14 OT and PT prescribers, 5 specialized technicians and 5 WPSD users. The second phase aimed at improving the overall functionality of the app and consisted in the development, test and evaluation of the prototypes v1, v2, v3 and v4. A total of 59 prescribers tested and evaluated these prototypes by means of open interviews, semi-structured questionnaires and focus groups. The third phase focused in the usability aspects of the app. It consisted in the development and test of the prototype v5. Eight technology specialists assessed its usability through heuristics evaluation. RESULTS Data collected in phase one indicated there is a lack of standardization on the prescription of postural support devices (PSD). A divergent nomenclature for the PSDs was also found and classified in eight categories. These information guided the development of the first prototype of the EasySeating app. Phase two results pointed that the prescribers value the insertion of the app into their clinical practice, as it accelerates and increases the quality of the evaluation process and improves the organization of the prescription information. Significant suggestions for the improvement of the app were given during the users tests, including the use of images to represent the PSDs. The usability tests from the third phase revealed two strong issues that must be solved: the need of greater feedback and failures in the persistence of the input data. CONCLUSIONS This study demonstrated that there is a lack of systematization of the WPSD prescription process. The evaluation of the developed EasySeating app demonstrated that there is a potential to standardize, integrate and organize the WPSD prescription information, supporting and facilitating the decision making process of the prescribers. CLINICALTRIAL This study was approved by the Research Ethics Board of the Universidade de São Paulo (registered protocol n°53929516.6.0000.0065) URL - http://plataformabrasil.saude.gov.br/login.jsf

Foucault as Superauthor

2019 ◽  
Vol 29 (2) ◽  
pp. 104-125
Keyword(s):  
Free Speech ◽  
Second Phase ◽  
Contemporary Society ◽  
Sovereign Power ◽  
Ancient Greek ◽  
Main Motivation ◽  
Critical Attitude ◽  
The Third ◽  
Third Phase ◽  
Lecture Courses

Three phases in Foucault’s examination of authorship and free speech were essential to him throughout his life. They can be linked to such texts as the three lectures “What is an Author?” (first phase), “What is Critique?,” and “What is Revolution?” (second phase), and the two lecture courses, “Fearless Speech,” and “The Courage of Truth” (third phase). Initially, Foucault merely describes the founders of discursivity (hence, “superauthors”), among whom he reckoned only Marx and Freud, as the sole alternative to his own conceptualization of the author function, which is exhibited en masse in contemporary society. He then modifies his views on superauthorship by making Kant the paradigm and by linking his own concept of free speech to a Kan-tian critical attitude. However, Foucault claims only the half of Kant’s philosophical legacy that is related to the study of the ontology of the self.The article advances the hypothesis that the sovereign power of speech, which can be found in Marx and Heidegger and in generally in the concept of “superauthorship,” becomes unacceptable for Foucault. During the third phase, the danger of a tyrannical use of free speech compels Foucault to make a number of fruitful but questionable choices in his work. He focuses on a single aspect of free speech in which a speaker is in a weaker position and therefore has to overcome his fear in order to tell the truth. Foucault associates this kind of free speech with the ancient Greek notion of parrhesia, which according to his interpretation means “fearless speech”; however, this reading is not always supported by the ancient Greek sources. Foucault’s deliberations bring him to the radical conclusion that free speech transforms into performative “aesthetics of existence.” Foucault’s main motivation for pursuing this line of thought all through his life was to investigate his own abilities and powers as an author

Some Special Aspects of Hypersonic Flow Fields

1959 ◽  
Vol 63 (585) ◽  
pp. 508-512 ◽  
Author(s):  
K. W. Mangler
Keyword(s):  
Hypersonic Flow ◽  
High Speed ◽  
Flow Fields ◽  
The Body ◽  
Lower Velocity ◽  
Bow Wave ◽  
Total Head ◽  
Bow Shocks ◽  
Lower Entropy ◽  
Subsonic Region

When a body moves through air at very high speed at such a height that the air can be considered as a continuum, the distinction between sharp and blunt noses with their attached or detached bow shocks loses its significance, since, in practical cases, the bow wave is always detached and fairly strong. In practice, all bodies behave as blunt shapes with a smaller or larger subsonic region near the nose where the entropy and the corresponding loss of total head change from streamline to streamline due to the curvature of the bow shock. These entropy gradients determine the behaviour of the hypersonic flow fields to a large extent. Even in regions where viscosity effects are small they give rise to gradients of the velocity and shear layers with a lower velocity and a higher entropy near the surface than would occur in their absence. Thus one can expect to gain some relief in the heating problems arising on the surface of the body. On the other hand, one would lose farther downstream on long slender shapes as more and more air of lower entropy is entrained into the boundary layer so that the heat transfer to the surface goes up again. Both these flow regions will be discussed here for the simple case of a body of axial symmetry at zero incidence. Finally, some remarks on the flow field past a lifting body will be made. Recently, a great deal of information on these subjects has appeared in a number of reviewing papers so that little can be added. The numerical results on the subsonic flow regions in Section 2 have not been published before.

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