Experimental and Numerical investigations on the Laser Shock Peening applied to thick components

In aeronautical constructions, fatigue is an issue of great concern. Laser Shock Peening is an innovative technology which promises considerable improvements to the development of a residual stress field capable of mitigative fatigue induced failures. The process has been successfully used in military applications for compressor and fan blades and for primary structures and is being introduced in the commercial aviation. The physical principles of the Laser Shock Peening, such as the Plasma Generation and the Shock Waves propagation, are reviewed and the cost/benefits of the technology are discussed. In order to investigate the influence of Laser Shock Peening on fatigue life of thick components, a test campaign was carried out by the author within EADS - Innovation Works Deutschland; the test campaign brought out that the Laser Shock Peening is capable of sensitive fatigue strength enhancements. Some unexpected failures occurred during the experimental activities. In order to investigate this unforeseen behavior, numerical simulations by means of the finite element method were carried out by the author at the Department of Aerospace Engineering of University of Pisa regarding the specimens involved in the test campaign. The simulations highlighted a modification of the stress field in Laser Shock Peened specimens which explains the unexpected failures

Methods and protocols for incremental exercise testing in tetraplegia, using arm-crank ergometry assisted by Functional Electrical Stimulation

Cervical spinal cord injury (SCI) leads to tetraplegia, with paralysis and loss of sensation in the upper and lower limbs. The associated sedentary lifestyle results in an increased risk of cardiovascular disease. To address this, we require the design of exercise modalities aimed specifically at tetraplegia and methods to assess their efficacy. This paper describes methods for arm-crank ergometry (ACE) assisted by Functional Electrical Stimulation (FES) applied to the biceps and triceps. The instrumented ergometer enables work-rate control during exercise, implemented here for incremental exercise testing during FES-ACE. Detailed protocols for the tests are given. Experimental data collected during exercise tests with tetraplegic volunteers are provided to illustrate the feasibility of the proposed approach to testing and data analysis. Incremental tests enabled calculation of peak power output and peak oxygen uptake. We propose that the high-precision exercise testing protocols described here are appropriate to assess the efficacy of the novel exercise modality, FES-ACE, in tetraplegia

Preliminary Validation of a Mobility Obstacle Course for Persons with Mobility Impairment

The purpose of this study was to assess the reliability and validity of a mobility obstacle course for women with mobility impairments. Participants included 72 adult women with permanent physical disabilities including arthritis, orthopedic conditions, paraplegia, and others. The 60-m course consisted of carpeted runways and turns, ramps, a doorway, a transfer, and object manipulation. Participants completed two trials, walking or wheeling through the course as quickly as possible, safely and without running. Total course time and peak heart rate data were correlated with SF-36 health survey subscales. Overall, peak heart rate was significantly (p \u3c .05) correlated with physical functioning (r = -.328), limitations due to physical functioning (r = .261), and pain (r = .296). Total course time was significantly correlated with physical functioning. These findings indicate very high reliability and preliminary evidence of validity

Comparing Technical Students\u27 L1 and L2 Reading Levels

本論は日本の大学で工学を専攻する日本人学生を対象とした読解力についての研究である。被験者となる学生は3つの大学に及び,学生の日本語と英語での読解力の差を検討した。日本語と英語の読解力において学力の混在したクラスの学生(2大学)のほうが推薦入試によるクラス(1大学)より読解力が優れていた。本研究により日本語で読解力の劣る学生は英語での読解力が劣ることが窺がわれた。この点は今後の課題となった

The Flexure-based Microgap Rheometer (FMR)

Submitted to J. Rheol.We describe the design and construction of a new microrheometer designed to facilitate the viscometric study of complex fluids with very small sample volumes (1-10 μl)and gaps of micrometer dimensions. The Flexure-based Microgap Rheometer (FMR) is a shear-rate-controlled device capable of measuring the shear stress in a plane Couette configuration with directly-controlled gaps between 1 μm and 200 μm. White light interferometry and a three-point nanopositioning stage using piezo-stepping motors are used to control the parallelism of the upper and lower shearing surfaces which are constructed from glass optical flats. A compound flexure system is used to hold the fluid sample testing unit between a drive spring connected to an ‘inchworm’ motor and an independent sensor spring. Displacements in the sensing flexure are detected using an inductive proximity sensor. Ready optical access to the transparent shearing surfaces enables monitoring of the structural evolution in the gap with a long working-distance video-microscope. This configuration then allows us to determine the microgap-dependent flow behavior of complex fluids over 5 decades of shear rate. We demonstrate the capability of the FMR by characterizing the complex stress and gap dependent flow behavior of a typical microstructured food product (mayonnaise) over the range of gaps from 8 to 100 μm and stresses from 10 to 1500 Pa. We correlate the gap-dependent rheological response to the microstructure of the emulsion and changes induced in the material by prolonged shearing.Dupont MIT Allianc

Aerobic fitness is a potential crucial factor in protecting paralympic athletes with locomotor impairments from atherosclerotic cardiovascular risk

PurposeTo test the hypothesis that aerobic fitness is inversely related to the risk of atherosclerotic cardiovascular disease (ACVD) in athletes with locomotor impairments deriving from health conditions, such as spinal cord injury (SCI), lower limb amputation, cerebral palsy, poliomyelitis, and other health conditions different from the previous ones.MethodsA total of 68 male athletes who competed in either summer or winter Paralympic games were divided in two health conditions groups (35 with SCI, mean age 37.28.0 years, and 33 with different health conditions, mean age 37.89.9 years) and in four sport type groups (skill, power, intermittent-mixed metabolism-and endurance). They were evaluated through anthropometric and blood pressure measurements, laboratory blood tests, and graded cardiopulmonary maximal arm cranking exercise test, with oxygen uptake peak (VO2peak) measurement. Cardiovascular risk profile was assessed in each athlete.ResultsThe prevalence of ACVD-risk factors in the overall population was 20.6% for hypertension; 47% and 55.9% for high values of total and LDL cholesterol, respectively; 22.1% for reduce glucose tolerance; and 8.8% for obesity. No difference was found between athletes with and without SCI, while the prevalence of obesity was significantly higher in those practicing skill sports (22.7%, p=0.035), which was the sport type group with Paralympic athletes with the lowest VO2peak (22.5 +/- 5.70 ml kg(-1) min(-1)). VO2peak was lower in athletes with SCI than those with different health conditions (28.6 +/- 10.0 vs 33.6 +/- 8.9 ml kg(-1) min(-1)p=0.03), and in those with 3-4 risk factors (19.09 +/- 5.34 ml kg(-1) min(-1)) than those with 2 risk factors (27.1 +/- 5.50 ml kg(-1) min(-1)), 1 risk factor (31.6 +/- 8.55 ml kg(-1) min(-1)), or none (36.4 +/- 8.76 ml kg(-1) min(-1)) (p<0.001).ConclusionsThe present study suggests that having higher VO2peak seems to offer greater protection against ACVD in individuals with a locomotor impairment. Prescribing physical exercise at an intensity similar to that of endurance and intermittent sports should become a fundamental tool to promote health among people with a locomotor impairment.Open access funding provided by Universita degli Studi dell'Aquila within the CRUI-CARE Agreement