The COMPASS Collaboration at CERN has measured diffractive dissociation of 190 GeV/c pions into the π(-)π(-)π(+) final state using a stationary hydrogen target. A partial-wave analysis (PWA) was performed in bins of 3π mass and four-momentum transfer using the isobar model and the so far largest PWA model consisting of 88 waves. A narrow peak is observed in the f0(980)π channel with spin, parity and C-parity quantum numbers J(PC)=1(++).
View Article and Find Full Text PDFThe COMPASS collaboration at CERN has investigated pion Compton scattering, π(-)γ→π(-)γ, at center-of-mass energy below 3.5 pion masses. The process is embedded in the reaction π(-)Ni→π(-)γNi, which is initiated by 190 GeV pions impinging on a nickel target.
View Article and Find Full Text PDFThe COMPASS Collaboration at CERN has investigated the π- γ → π- π- π+ reaction at center-of-momentum energy below five pion masses, sqrt[s]<5m(π), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t'<0.001 GeV2/c2.
View Article and Find Full Text PDFGiven that automobile crashes are the largest single cause of death for pregnant females, scientists are developing advanced computer models of pregnant occupants. The purpose of this study is to quantify the dynamic material properties of the human uterus in order to increase the biofidelity of these models. A total of 19 dynamic tension tests were performed on pregnant human uterus tissues taken from six separate donors.
View Article and Find Full Text PDFPurpose: Interactive water displays are becoming increasingly popular and can result in direct eye contact. Therefore, the purpose of this study is to investigate eye injury risk from high speed water stream impacts and to provide biomechanically based design parameters for water toys and water park fountains.
Methods: An experimental matrix of 38 tests was developed to impact eight porcine eyes with water streams using a customized pressure system.
Purpose: To evaluate the risk of eye injuries by determining intraocular pressure during high speed projectile impacts.
Methods: A pneumatic cannon was used to impact eyes with a variety of projectiles at multiple velocities. Intraocular pressure was measured with a small pressure sensor inserted through the optic nerve.
This study reports the results of 38 infraorbital maxilla impacts performed on male cadavers. Impacts were performed using an unpadded, cylindrical impactor (3.2 kg) at velocities between 1 and 5 m/s.
View Article and Find Full Text PDFThe current understanding of the tolerance of the frontal bone to blunt impact is limited. Previous studies have utilized vastly different methods, which limits the use of statistical analyses to determine the tolerance of the frontal bone. The purpose of this study is to determine the tolerance of the frontal bone to blunt impact.
View Article and Find Full Text PDFObjective: The goals of this study were to measure the ability of catcher's masks to attenuate head accelerations on impact with a baseball and to compare these head accelerations to established injury thresholds for mild traumatic brain injury.
Design: Testing involved using a pneumatic cannon to shoot baseballs at an instrumented Hybrid III headform (a 50th percentile male head and neck) with and without a catcher's mask on the head. The ball speed was controlled from approximately 26.
The nasal bone is among the most frequently broken facial bone due to all types of trauma and is the most frequently fractured facial bone due to motor vehicle collisions. This study reports the results of anterior-posterior impacts performed on male cadavers using a free-falling impactor with a flat impacting surface. The force at fracture onset was determined using an acoustic emission sensor.
View Article and Find Full Text PDFThe COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the π- π- π+ final state using a 190 GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of 420,000 events taken at values of the squared 4-momentum transfer t' between 0.1 and 1 GeV2/c2.
View Article and Find Full Text PDFWith the increasing use of computational models there is a growing need to establish and analyze the material properties of biological tissues. The purpose of this study is to analyze and compare the various methods used for reporting stress and strain for biological materials. For this study, three biological materials (bone, sclera, and placenta) were used to compare the effects of reporting stress and strain relationships using various formulations.
View Article and Find Full Text PDFBiomed Sci Instrum
February 2016
Half of eye injuries in the United States are caused by a blunt impact and more specifically, eye injuries effecting children often result from projectile shooting toys. The purpose of this study is to evaluate the risk of eye injuries of currently available projectile shooting toys. In order to assess the risk of each toy, a Facial and Ocular Countermeasure Safety (FOCUS) headform was used to measure the force applied to the eye during each hit for a total of 18 tests.
View Article and Find Full Text PDFObjective: To determine the dynamic rupture pressure of the human eye by using an in vitro high-rate pressurization system to investigate blunt-impact eye injuries.
Methods: Internal pressure was dynamically induced in the eye by means of a drop-tower pressurization system. The internal eye pressure was measured with a small pressure sensor inserted into the eye through the optic nerve.
As a result of trauma, approximately 30,000 people become blind in one eye every year in the United States. A common injury prediction tool used for eye injuries is computational modeling, which requires accurate material properties to produce reliable results. The purpose of this study is to determine the dynamic material properties of the human sclera.
View Article and Find Full Text PDFThis study describes a method for utilizing Acoustic Emission (AE) in facial fracture detection and demonstrates the association between fracture and acoustic emission magnitude. AE sensors were mounted to the frontal bone and mandible of cadaver skulls (n=14) exposed to impacts to the frontal bone, nasal bone, maxilla and mandible. The presence of AE during fracture and non-fracture tests necessitated the development of a threshold to distinguish AE associated with fracture.
View Article and Find Full Text PDFOver 1.9 million people suffer from eye injuries in the United States, occurring from automobile accidents, sports related impacts, and military combat. The purpose of the current study is to analyze the rupture pressure of human eyes using a high rate pressurization system.
View Article and Find Full Text PDFFirst measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.
View Article and Find Full Text PDFAt the Cooler Synchrotron COSY/Jülich spin-correlation parameters in elastic proton-proton (pp) scattering have been measured with a 2.11 GeV polarized proton beam and a polarized hydrogen atomic beam target. We report results for A(NN), A(SS), and A(SL) for c.
View Article and Find Full Text PDFExcitation functions A(N)(p(p),Theta(c.m.)) of the analyzing power in pp--> elastic scattering have been measured with a polarized atomic hydrogen target for projectile momenta p(p) between 1000 and 3300 MeV/ c.
View Article and Find Full Text PDFPhys Rev C Nucl Phys
February 1995