Fatigue properties of type 316LN stainless steel in air and mercury

NASA Astrophysics Data System (ADS)

Strizak, J. P.; Tian, H.; Liaw, P. K.; Mansur, L. K.

2005-08-01

An extensive fatigue testing program on 316LN stainless steel was recently carried out to support the design of the mercury target container for the spallation neutron source (SNS) that is currently under construction at the Oak Ridge National Laboratory in the United States. The major objective was to determine the effects of mercury on fatigue behavior. The S- N fatigue behavior of 316LN stainless steel is characterized by a family of bilinear fatigue curves which are dependent on frequency, environment, mean stress and cold work. Generally, fatigue life increases with decreasing stress and levels off in the high cycle region to an endurance limit below which the material will not fail. For fully reversed loading as well as tensile mean stress loading conditions mercury had no effect on endurance limit. However, at higher stresses a synergistic relationship between mercury and cyclic loading frequency was observed at low frequencies. As expected, fatigue life decreased with decreasing frequency, but the response was more pronounced in mercury compared with air. As a result of liquid metal embrittlement (LME), fracture surfaces of specimens tested in mercury showed widespread brittle intergranular cracking as opposed to typical transgranular cracking for specimens tested in air. For fully reversed loading (zero mean stress) the effect of mercury disappeared as frequency increased to 10 Hz. For mean stress conditions with R-ratios of 0.1 and 0.3, LME was still evident at 10 Hz, but at 700 Hz the effect of mercury had disappeared ( R = 0.1). Further, for higher R-ratios (0.5 and 0.75) fatigue curves for 10 Hz showed no environmental effect. Finally, cold working (20%) increased tensile strength and hardness, and improved fatigue resistance. Fatigue behavior at 10 and 700 Hz was similar and no environmental effect was observed.

Remote monitoring and prognosis of fatigue cracking in steel bridges with acoustic emission

NASA Astrophysics Data System (ADS)

Yu, Jianguo Peter; Ziehl, Paul; Pollock, Adrian

2011-04-01

Acoustic emission (AE) monitoring is desirable to nondestructively detect fatigue damage in steel bridges. Investigations of the relationship between AE signals and crack growth behavior are of paramount importance prior to the widespread application of passive piezoelectric sensing for monitoring of fatigue crack propagation in steel bridges. Tests have been performed to detect AE from fatigue cracks in A572G50 steel. Noise induced AE signals were filtered based on friction emission tests, loading pattern, and a combined approach involving Swansong II filters and investigation of waveforms. The filtering methods based on friction emission tests and load pattern are of interest to the field evaluation using sparse datasets. The combined approach is suitable for data filtering and interpretation of actual field tests. The pattern recognition program NOESIS (Envirocoustics) was utilized for the evaluation of AE data quality. AE parameters are associated with crack length, crack growth rate, maximum stress intensity and stress intensity range. It is shown that AE hits, counts, absolute energy, and signal strength are able to provide warnings at the critical cracking level where cracking progresses from stage II (stable propagation) to stage III (unstable propagation which may result in failure). Absolute energy rate and signal strength rate may be better than count rate to assess the remaining fatigue life of inservice steel bridges.

Metabolomic markers of fatigue: Association between circulating metabolome and fatigue in women with chronic widespread pain.

PubMed

Freidin, Maxim B; Wells, Helena R R; Potter, Tilly; Livshits, Gregory; Menni, Cristina; Williams, Frances M K

2018-02-01

Fatigue is a sensation of unbearable tiredness that frequently accompanies chronic widespread musculoskeletal pain (CWP) and inflammatory joint disease. Its mechanisms are poorly understood and there is a lack of effective biomarkers for diagnosis and onset prediction. We studied the circulating metabolome in a population sample characterised for CWP to identify biomarkers showing specificity for fatigue. Untargeted metabolomic profiling was conducted on fasting plasma and serum samples of 1106 females with and without CWP from the TwinsUK cohort. Linear mixed-effects models accounting for covariates were used to determine relationships between fatigue and metabolites. Receiver operating curve (ROC)-analysis was used to determine predictive value of metabolites for fatigue. While no association between fatigue and metabolites was identified in twins without CWP (n=711), in participants with CWP (n=395), levels of eicosapentaenoate (EPA) ω-3 fatty acid were significantly reduced in those with fatigue (β=-0.452±0.116; p=1.2×10 -4 ). A significant association between fatigue and two other metabolites also emerged when BMI was excluded from the model: 3-carboxy-4-methyl-5-propyl-2-furanpropanoate (CMPF), and C-glycosyltryptophan (p=1.5×10 -4 and p=3.1×10 -4 , respectively). ROC analysis has identified a combination of 15 circulating metabolites with good predictive potential for fatigue in CWP (AUC=75%; 95% CI 69-80%). The results of this agnostic metabolomics screening show that fatigue is metabolically distinct from CWP, and is associated with a decrease in circulating levels of EPA. Our panel of circulating metabolites provides the starting point for a diagnostic test for fatigue in CWP. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

The association of fatigue, comorbidity burden, disease activity, disability and gross domestic product in patients with rheumatoid arthritis. Results from 34 countries participating in the Quest-RA program.

PubMed

Grøn, Kathrine Lederballe; Ornbjerg, Lykke Midtbøll; Hetland, Merete Lund; Aslam, Fawad; Khan, Nasim A; Jacobs, Johannes W G; Henrohn, Dan; Rasker, J J; Kauppi, Markku J; Lang, Hui-Chu; Mota, Licia M H; Aggarwal, Amita; Yamanaka, Hisahi; Badsha, Humeira; Gossec, Laure; Cutolo, Maurizio; Ferraccioli, Gianfranco; Gremese, Elisa; Bong Lee, Eun; Inanc, Nevsun; Direskeneli, Haner; Taylor, Peter; Huisman, Margriet; Alten, Rieke; Pohl, Christoph; Oyoo, Omondi; Stropuviene, Sigita; Drosos, Alexandrosos A; Kerzberg, Eduardo; Ancuta, Codorina; Mofti, Ayman; Bergman, Martin; Detert, Jaqueline; Selim, Zaraa I; Abda, Essam A; Rexhepi, Blerta; Sokka, Tuulikki

2014-01-01

The aim is to assess the prevalence of comorbidities and to further analyse to which degree fatigue can be explained by comorbidity burden, disease activity, disability and gross domestic product (GDP) in patients with rheumatoid arthritis (RA). Nine thousands eight hundred seventy-four patients from 34 countries, 16 with high GDP (>24.000 US dollars [USD] per capita) and 18 low-GDP countries (<24.000 USD) participated in the Quantitative Standard monitoring of Patients with RA (QUEST-RA) study. The prevalence of 31 comorbid conditions, fatigue (0-10 cm visual analogue scale [VAS] [10=worst]), disease activity in 28 joints (DAS28), and physical disability (Health Assessment Questionnaire score [HAQ]) were assessed. Univariate and multivariate linear regression analyses were performed to assess the association between fatigue and comorbidities, disease activity, disability and GDP. Overall, patients reported a median of 2 comorbid conditions of which hypertension (31.5%), osteoporosis (17.6%), osteoarthritis (15.5%) and hyperlipidaemia (14.2%) were the most prevalent. The majority of comorbidities were more common in high-GDP countries. The median fatigue score was 4.4 (4.8 in low-GDP countries and 3.8 in high-GDP countries, p<0.001). In low-GDP countries 25.4% of the patients had a high level of fatigue (>6.6) compared with 23.0% in high-GDP countries (p<0.001). In univariate analysis, fatigue increased with increasing number of comorbidities, disease activity and disability in both high- and low-GDP countries. In multivariate analysis of all countries, these 3 variables explained 29.4% of the variability, whereas GDP was not significant. Fatigue is a widespread problem associated with high comorbidity burden, disease activity and disability regardless of GDP.

An overview of fatigue failures at the Rocky Flats Wind System Test Center

NASA Technical Reports Server (NTRS)

Waldon, C. A.

1981-01-01

Potential small wind energy conversion (SWECS) design problems were identified to improve product quality and reliability. Mass produced components such as gearboxes, generators, bearings, etc., are generally reliable due to their widespread uniform use in other industries. The likelihood of failure increases, though, in the interfacing of these components and in SWECS components designed for a specific system use. Problems relating to the structural integrity of such components are discussed and analyzed with techniques currently used in quality assurance programs in other manufacturing industries.

78 FR 22435 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-16

... to widespread fatigue damage (WFD). A replacement was developed to support the airplane's limit of... detect and correct fatigue cracking in certain upper chords of the upper deck floor beam, which could... Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal...

78 FR 25905 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-03

... that the frame-to-floor beam attachment is subject to widespread fatigue damage (WFD). This proposed AD... fatigue cracking at the frame-to-floor beam attachment, on both the left- and right-sides, which could... between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. For service information...

78 FR 14719 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-07

... that the fuselage skin just above certain lap splice locations is subject to widespread fatigue damage... fatigue cracking of the fuselage skin, which could result in reduced structural integrity of the airplane.... Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except...

Serum cytokine levels related to multiple dimensions of fatigue in patients with primary Sjögren's syndrome

PubMed Central

Hartkamp, A; Geenen, R; Bijl, M; Kruize, A; Godaert, G; Derksen, R

2004-01-01

Methods: Sixty female patients with pSS filled out a questionnaire to assess multiple dimensions of fatigue. Scores were compared with values in a population based control group (n = 139). Levels of interleukin (IL)1ß, IL2, IL6, IL10, and tumour necrosis factor α were measured in serum with commercial sandwich ELISAs. The relationship between self reported dimensions of fatigue and these serum cytokine levels was determined. Results: Patients with pSS had high scores at all dimensions of fatigue (p<0.001): general fatigue, physical fatigue, reduced activity, reduced motivation, and mental fatigue. Fatigue levels were not related to serum cytokine levels. The incidental finding that reduced motivation was higher in patients with detectable serum levels of IL10 (p = 0.04) disappeared after correction for multiple testing. Conclusion: Fatigue is prominent in patients with pSS and involves all dimensions of fatigue. The findings do not suggest a widespread effect of circulating cytokines on multiple aspects of fatigue. PMID:15361396

78 FR 63132 - Airworthiness Directives; Fokker Services B.V. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-23

... passenger door are subject to widespread fatigue damage (WFD). This proposed AD would require inspecting the.... We are proposing this AD to prevent fatigue cracking of such butt-joints, which could result in..., Room W12-140, 1200 New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through...

Fatigue and Creep-Fatigue Deformation of an Ultra-Fine Precipitate Strengthened Advanced Austenitic Alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

M.C. Carroll; L.J. Carroll

An advanced austenitic alloy, HT-UPS (high-temperature ultrafine-precipitation-strengthened), has been identified as an ideal candidate material for the structural components of fast reactors and energy-conversion systems. HT-UPS alloys demonstrate improved creep resistance relative to 316 stainless steel (SS) through additions of Ti and Nb, which precipitate to form a widespread dispersion of stable nanoscale metallic carbide (MC) particles in the austenitic matrix. The low-cycle fatigue and creep-fatigue behavior of an HT-UPS alloy have been investigated at 650 °C and a 1.0% total strain, with an R-ratio of -1 and hold times at peak tensile strain as long as 150 min. Themore » cyclic deformation response of HT-UPS is directly compared to that of standard 316 SS. The measured values for total cycles to failure are similar, despite differences in peak stress profiles and in qualitative observations of the deformed microstructures. Crack propagation is primarily transgranular in fatigue and creep-fatigue of both alloys at the investigated conditions. Internal grain boundary damage in the form of fine cracks resulting from the tensile hold is present for hold times of 60 min and longer, and substantially more internal cracks are quantifiable in 316 SS than in HT-UPS. The dislocation substructures observed in the deformed material differ significantly; an equiaxed cellular structure is observed in 316 SS, whereas in HT-UPS the microstructure takes the form of widespread and relatively homogenous tangles of dislocations pinned by the nanoscale MC precipitates. The significant effect of the fine distribution of precipitates on observed fatigue and creep-fatigue response is described in three distinct behavioral regions as it evolves with continued cycling.« less

75 FR 81427 - Airworthiness Directives; The Boeing Company Model 747-200C, -200F, -400, -400D, and -400F Series...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-28

.... This AD results from a structural review of affected skin lap joints for widespread fatigue damage. We are issuing this AD to prevent fatigue cracking in certain lap joints, which could result in rapid... operation beyond 15,000 total flight cycles after doing the proposed modification. Boeing stated that...

Cognitive and Physical Fatigue Tasks Enhance Pain, Cognitive Fatigue and Physical Fatigue in People with Fibromyalgia

PubMed Central

Dailey, Dana L; Keffala, Valerie J; Sluka, Kathleen A

2014-01-01

Objective Fibromyalgia is a condition characterized by chronic widespread muscle pain and fatigue. The primary objective of this study was to determine if pain, perceived cognitive fatigue, and perceived physical fatigue were enhanced in participants with fibromyalgia compared to healthy controls during a cognitive fatigue task, a physical fatigue task and a dual fatigue task. Methods Twenty four people with fibromyalgia and 33 healthy controls completed pain, fatigue and function measures. A cognitive fatigue task (Controlled Oral Word Association Test) and physical fatigue task (Valpar peg test) were done individually and combined for a dual fatigue task. Resting pain, perceived cognitive fatigue and perceived physical fatigue were assessed during each task using visual analogue scales. Function was assessed with shoulder range of motion and grip. Results People with fibromyalgia had significantly higher increases in pain, cognitive fatigue and physical fatigue when compared to healthy controls after completion of a cognitive fatigue task, a physical fatigue task, or a dual fatigue task (p<0.01). People with fibromyalgia performed equivalently on measures of physical performance and cognitive performance on the physical and cognitive fatigue tasks, respectively. Conclusions These data show that people with fibromyalgia show larger increases in pain, perceived cognitive fatigue and perceived physical fatigue to both cognitive and physical fatigue tasks compared to healthy controls. The increases in pain and fatigue during cognitive and physical fatigue tasks could influence subject participation in daily activities and rehabilitation. PMID:25074583

75 FR 13046 - Airworthiness Directives; The Boeing Company Model 747-200C, -200F, -400, -400D, and -400F Series...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-18

.... This proposed AD results from a structural review of affected skin lap joints for widespread fatigue damage. We are proposing this AD to prevent fatigue cracking in certain lap joints, which could result in...., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. For service...

Intrinsically higher fatigue cracking resistance of the penetrable and movable incoherent twin boundary

NASA Astrophysics Data System (ADS)

Li, L. L.; Zhang, P.; Zhang, Z. J.; Zhang, Z. F.

2014-01-01

Incoherent twin boundaries (ITBs) are widespread and play a crucial role in unidirectional deformation behavior of materials, however, the intrinsic role of individual ITB under cyclic loading remains elusive. Here we show the fatigue cracking behavior of Cu bicrystal with an ITB as its sole interface for the first time. The slip bands (SBs) could transfer through the ITB; meanwhile, the ITB could migrate with the motion of partial dislocations. Both the penetrability and mobility contribute to the higher fatigue cracking resistance of the ITB and hence the fatigue crack nucleates along the SBs preferentially. These new findings not only shed light on the fatigue cracking mechanisms of a penetrable boundary with direct evidence but also could provide important implications for future interfacial optimization of metallic materials.

Are Traditional Remedies Useful in Management of Fibromyalgia and Chronic Fatigue Syndrome? A Review Study

PubMed Central

Mahjoub, Fatemeh; Salari, Roshanak; Noras, Mohammad Reza; Yousefi, Mahdi

2017-01-01

Fibromyalgia and chronic fatigue syndrome are disorders that often occur simultaneously and are characterized by widespread pain and persistent fatigue. The patients are associated with disability and impairment social and physical functions. There are many remedies in traditional Persian medicine suggested for management of the disease complaints. The aim of this study was to investigate the clinical presentations and pathophysiology of disorders with the basic and principal textbook of traditional Persian medicine written by Avicenna (Canon of Medicine). According to Persian medicine, the term E’aya can be matched by mentioned disorders. Avicenna believed that strenuous activities play an important role in the beginning of some types of fatigue. He classified fatigue into 4 groups, and in each type the clinical symptoms varied. The multifaceted entity of fibromyalgia and chronic fatigue syndrome in Persian medicine and conventional medicine suggests multidisciplinary therapies in management of these disabling disorders. PMID:28597692

High Speed Research Program Sonic Fatigue

NASA Technical Reports Server (NTRS)

Rizzi, Stephen A. (Technical Monitor); Beier, Theodor H.; Heaton, Paul

2005-01-01

The objective of this sonic fatigue summary is to provide major findings and technical results of studies, initiated in 1994, to assess sonic fatigue behavior of structure that is being considered for the High Speed Civil Transport (HSCT). High Speed Research (HSR) program objectives in the area of sonic fatigue were to predict inlet, exhaust and boundary layer acoustic loads; measure high cycle fatigue data for materials developed during the HSR program; develop advanced sonic fatigue calculation methods to reduce required conservatism in airframe designs; develop damping techniques for sonic fatigue reduction where weight effective; develop wing and fuselage sonic fatigue design requirements; and perform sonic fatigue analyses on HSCT structural concepts to provide guidance to design teams. All goals were partially achieved, but none were completed due to the premature conclusion of the HSR program. A summary of major program findings and recommendations for continued effort are included in the report.

The London Fibromyalgia Epidemiology Study: comparing the demographic and clinical characteristics in 100 random community cases of fibromyalgia versus controls.

PubMed

White, K P; Speechley, M; Harth, M; Ostbye, T

1999-07-01

To identify demographic and clinical features that distinguish fibromyalgia (FM) from other chronic widespread pain. We identified 100 confirmed FM cases, 76 widespread pain controls, and 135 general controls in a random community survey of 3395 noninstitutionalized adults living in London, Ontario. FM cases were distinguished from pain controls using the 1990 American College of Rheumatology (ACR) classification criteria for FM. The mean age of FM cases was 47.8 years (range 19 to 86), the same as for pain controls; 86% of FM cases were female versus 67.1% of pain controls (p < 0.01). FM cases were less educated than general controls (p = 0.03). Male and female FM cases were similar, except females were older and reported more major symptoms (both p = 0.02). FM cases reported more severe pain and fatigue, more symptoms, more major symptoms, and worse overall health than pain controls or general controls. The most commonly reported major symptoms among FM cases were musculoskeletal pain (77.3%), fatigue (77.3%), severe fatigue lasting 24 h after minimal activity (77.0%), nonrestorative sleep (65.7%), and insomnia (56.0%). Subjects with 11-14 tender points were more similar to those with 15-18 tender points than to those with 7-10 points in 11 of 14 clinical variables. On multivariate analysis, 4 symptoms distinguished FM cases from pain controls: pain severity (p = 0.004), severe fatigue lasting 24 h after minimal activity (p = 0.006), weakness (p = 0.008), and self-reported swelling of neck glands (p = 0.01). In the general population, adults who meet the ACR definition of FM appear to have distinct features compared to those with chronic widespread pain who do not meet criteria.

Beyond pain in fibromyalgia: insights into the symptom of fatigue

PubMed Central

2013-01-01

Fatigue is a disabling, multifaceted symptom that is highly prevalent and stubbornly persistent. Although fatigue is a frequent complaint among patients with fibromyalgia, it has not received the same attention as pain. Reasons for this include lack of standardized nomenclature to communicate about fatigue, lack of evidence-based guidelines for fatigue assessment, and a deficiency in effective treatment strategies. Fatigue does not occur in isolation; rather, it is present concurrently in varying severity with other fibromyalgia symptoms such as chronic widespread pain, unrefreshing sleep, anxiety, depression, cognitive difficulties, and so on. Survey-based and preliminary mechanistic studies indicate that multiple symptoms feed into fatigue and it may be associated with a variety of physiological mechanisms. Therefore, fatigue assessment in clinical and research settings must consider this multi-dimensionality. While no clinical trial to date has specifically targeted fatigue, randomized controlled trials, systematic reviews, and meta-analyses indicate that treatment modalities studied in the context of other fibromyalgia symptoms could also improve fatigue. The Outcome Measures in Rheumatology (OMERACT) Fibromyalgia Working Group and the Patient Reported Outcomes Measurement Information System (PROMIS) have been instrumental in propelling the study of fatigue in fibromyalgia to the forefront. The ongoing efforts by PROMIS to develop a brief fibromyalgia-specific fatigue measure for use in clinical and research settings will help define fatigue, allow for better assessment, and advance our understanding of fatigue. PMID:24289848

Ankle and knee biomechanics during normal walking following ankle plantarflexor fatigue.

PubMed

Hunt, Michael A; Hatfield, Gillian L

2017-08-01

The purpose of this study was to investigate the immediate effects of unilateral ankle plantarflexor fatigue on bilateral knee and ankle biomechanics during gait. Lower leg kinematics, kinetics, and muscle activation were assessed before and after an ankle plantarflexor fatiguing protocol in 31 healthy individuals. Fatigue (defined as >10% reduction in maximal isometric ankle plantarflexor torque production and a downward shift in the median power frequency of both heads of the gastrocnemius muscle of the fatigued limb) was achieved in 18 individuals, and only their data were used for analysis purposes. Compared to pre-fatigue walking trials, medial gastrocnemius activity was significantly reduced in the study (fatigued) limb. Other main changes following fatigue included significantly more knee flexion during loading, and an associated larger external knee flexion moment in the study limb. At the ankle joint, participants exhibited significantly less peak plantarflexion (occurring at toe-off) with fatigue. No significant differences were observed in the contralateral (non-fatigued) limb. Findings from this study indicate that fatigue of the ankle plantarflexor muscle does not produce widespread changes in gait biomechanics, suggesting that small to moderate changes in maximal ankle plantarflexor force production capacity (either an increase or decrease) will not have a substantial impact on normal lower limb functioning during gait. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluating Fatigue in Operational Settings: The NASA Ames Fatigue Countermeasures Program

NASA Technical Reports Server (NTRS)

Rosekind, Mark R.; Gregory, Kevin; Miller, Donna; Webbon, Lissa; Oyung, Ray

1996-01-01

In response to a 1980 Congressional request, NASA Ames initiated a program to examine fatigue in flight operations. The Program objectives are to examine fatigue, sleep loss, and circadian disruption in flight operations, determine the effects of these factors on flight crew performance, and the development of fatigue countermeasures. The NASA Ames Fatigue Countermeasures Program conducts controlled laboratory experiments, full-mission flight simulations, and field studies. A range of subjective, behavioral, performance, physiological, and environmental measures are used depending on study objectives. The Program has developed substantial expertise in gathering data during actual flight operations and in other work settings. This has required the development of ambulatory and other measures that can be carried throughout the world and used at 41,000 feet in aircraft cockpits. The NASA Ames Fatigue Countermeasures Program has examined fatigue in shorthaul, longhaul, overnight cargo, and helicopter operations. A recent study of planned cockpit rest periods demonstrated the effectiveness of a brief inflight nap to improve pilot performance and alertness. This study involved inflight reaction time/vigilance performance testing and EEG/EOG measures of physiological alertness. The NASA Ames Fatigue Countermeasures Program has applied scientific findings to the development of education and training materials on fatigue countermeasures, input to federal regulatory activities on pilot flight, duty, and rest requirements, and support of National Transportation Safety Board accident investigations. Current activities are examining fatigue in nonaugmented longhaul flights, regional/commuter flight operations, corporate/business aviation, and psychophysiological variables related to performance.

Surface-distributed low-frequency asynchronous stimulation delays fatigue of stimulated muscles.

PubMed

Maneski, Lana Z Popović; Malešević, Nebojša M; Savić, Andrej M; Keller, Thierry; Popović, Dejan B

2013-12-01

One important reason why functional electrical stimulation (FES) has not gained widespread clinical use is the limitation imposed by rapid muscle fatigue due to non-physiological activation of the stimulated muscles. We aimed to show that asynchronous low-pulse-rate (LPR) electrical stimulation applied by multipad surface electrodes greatly postpones the occurrence of muscle fatigue compared with conventional stimulation (high pulse rate, HPR). We compared the produced force vs. time of the forearm muscles responsible for finger flexion in 2 stimulation protocols, LPR (fL = 10 Hz) and HPR (fH = 40 Hz). Surface-distributed low-frequency asynchronous stimulation (sDLFAS) doubles the time interval before the onset of fatigue (104 ± 80%) compared with conventional synchronous stimulation. Combining the performance of multipad electrodes (increased selectivity and facilitated positioning) with sDLFAS (decreased fatigue) can improve many FES applications in both the lower and upper extremities. Copyright © 2013 Wiley Periodicals, Inc.

Customizing treatment of chronic fatigue syndrome and fibromyalgia: the role of perpetuating factors.

PubMed

Van Houdenhove, Boudewijn; Luyten, Patrick

2008-01-01

Syndromes characterized by chronic, medically unexplained fatigue, effort- and stress-intolerance, and widespread pain are highly prevalent in medicine. In chronic fatigue syndrome (CFS) and fibromyalgia (FM), various perpetuating factors may impair patients' quality of life and functioning and impede recovery. Although cognitive-behavioral and graded-exercise therapy are evidence-based treatments, the effectiveness and acceptability of therapeutic interventions in CFS/FM may largely depend on a customized approach taking the heterogeneity of perpetuating factors into account. Further research should clarify the aim and outcome of different treatment strategies in CFS/FM, as well as the underlying mechanisms of change, including those facilitating neurobiological recovery.

Effects of an endurance and resistance exercise program on persistent cancer-related fatigue after treatment.

PubMed

Dimeo, F; Schwartz, S; Wesel, N; Voigt, A; Thiel, E

2008-08-01

Fatigue is a relevant problem of cancer patients during and after treatment. Several studies have shown that exercise can improve quality of life and functional status of cancer patients undergoing chemo- or radiotherapy. However, there is a lack of information about the effects of this intervention on persistent cancer-related fatigue. Therefore, we assessed the effects of an exercise program on cancer-related fatigue after treatment. A consecutive series of 32 cancer patients with mild to severe persistent fatigue [scores on the Brief Fatigue Inventory (BFI) > 25] participated in a 3-week exercise program consisting of endurance (30 min walking on a treadmill) and resistance/coordination exercises for the major muscle groups. Fatigue, mood, and anxiety were assessed with questionnaires and physical performance with a stress test before and after the program. At the end of the program, we observed a significant increase of physical performance (workload at the anaerobic threshold pre 61 +/- 26 W, post 78 +/- 31 W, P < 0.0001) and reduction of global fatigue (Functional Assessment of Cancer Therapy: pre 45.7 +/- 13.4, post 52.6 +/- 12.4, P < 0.0001; BFI: pre 37.9 +/- 18.3, post 31.2 +/-17.1, P < 0.001). However, no significant improvement of cognitive fatigue or reduction of anxiety was observed. A 3-week exercise program leads to a substantial improvement of physical performance and reduction of mental and physical fatigue in cancer patients after treatment. However, this intervention does not affect depression, anxiety, or cognitive fatigue.

The Boeing 747 fatigue integrity program

NASA Technical Reports Server (NTRS)

Spencer, M. M.

1972-01-01

The fatigue integrity program which was established to insure economic operations and to provide foundation data for inspection and maintenance is discussed. Significant features of the 747 fatigue integrity program are: (1) fatigue analyses which are continually updated to reflect design changes, fatigue test results, and static and flight load survey measurements; (2) material selection and detail design by using initial fatigue analyses, service experience, and testing; and (3) fatigue testing to check detail design quality and to verify the analyses, culminated by the test of a structurally complete airframe. Fatigue stress analyses were performed with the aid of experimental as well as analytical procedures. Extensive application was made of the stress severity factor, developed at Boeing, for evaluating peak stresses in complex joints. A frame of reference was established by families of structural fatigue performance curves (S-N curves) encompassing the range of materials and fatigue qualities anticipated for the 747 airplane design.

Crew Factors in Flight Operations X: Alertness Management in Flight Operations

NASA Technical Reports Server (NTRS)

Rosekind, Mark R.; Gander, Philippa H.; Connell, Linda J.; Co, Elizabeth L.

1999-01-01

In response to a 1980 congressional request, NASA Ames Research Center initiated a Fatigue/Jet Lag Program to examine fatigue, sleep loss, and circadian disruption in aviation. Research has examined fatigue in a variety of flight environments using a range of measures (from self-report to performance to physiological). In 1991, the program evolved into the Fatigue Countermeasures Program, emphasizing the development and evaluation of strategies to maintain alertness and performance in operational settings. Over the years, the Federal Aviation Administration (FAA) has become a collaborative partner in support of fatigue research and other Program activities. From the inception of the Program, a principal goal was to return the information learned from research and other Program activities to the operational community. The objectives of this Education and Training Module are to explain what has been learned about the physiological mechanisms that underlie fatigue, demonstrate the application of this information in flight operations, and offer some specific fatigue counter-measure recommendations. It is intended for all segments of the aeronautics industry, including pilots, flight attendants, managers, schedulers, safety and policy personnel, maintenance crews, and others involved in an operational environment that challenges human physiological capabilities because of fatigue, sleep loss, and circadian disruption.

Crew Factors in Flight Operations X: Alertness Management in Flight Operations

NASA Technical Reports Server (NTRS)

Rosekind, Mark R.; Gander, Philippa H.; Connell, Linda J.; Co, Elizabeth L.

2001-01-01

In response to a 1980 congressional request, NASA Ames Research Center initiated a Fatigue/Jet Lag Program to examine fatigue, sleep loss, and circadian disruption in aviation. Research has examined fatigue in a variety of flight environments using a range of measures (from self-report to performance to physiological). In 1991, the program evolved into the Fatigue Countermeasures Program, emphasizing the development and evaluation of strategies to maintain alertness and performance in operational settings. Over the years, the Federal Aviation Administration (FAA) has become a collaborative partner in support of fatigue research and other Program activities. From the inception of the Program, a principal goal was to return the information learned from research and other Program activities to the operational community. The objectives of this Education and Training Module are to explain what has been learned about the physiological mechanisms that underlie fatigue, demonstrate the application of this information in flight operations, and offer some specific fatigue countermeasure recommendations. It is intended for all segments of the aeronautics industry, including pilots, flight attendants, managers, schedulers, safety and policy personnel, maintenance crews, and others involved in an operational environment that challenges human physiological capabilities because of fatigue, sleep loss, and circadian disruption.

Widespread pain: is an improved classification possible?

PubMed

MacFarlane, G J; Croft, P R; Schollum, J; Silman, A J

1996-09-01

The classification of widespread pain, proposed by the American College of Rheumatology (ACR) for use in the clinic as a screen for fibromyalgia, as described, does not require truly widespread pain. Studies considering the epidemiology of widespread pain per se may therefore require a definition with greater face validity, which might also show enhanced associations with other physical and psychological measures. We aimed to develop a more coherent definition of widespread pain for use in epidemiological studies and to compare performance in identifying individuals with significant morbidity. A group of 172 subjects who had participated in a community based study on the occurrence of pain were identified and categorized by their pain experience as indicated on line drawings of the body according to ACR definition and to a new, more stringent definition that required the presence of more diffuse limb pain. A number of other clinical and psychological measures were recorded for these individuals and the association between their pain status measures and these other variables was assessed and compared. Persons satisfying the newly proposed definition for chronic widespread pain, in comparison with those who satisfied only the present ACR definition, had a significantly higher score on the General Health Questionnaire [median difference (MD) 7.95% CI 1.13], a higher score on the Health and Fatigue Questionnaire (MD 10.95% CI 0.15), and greater problems with sleep (sleep problem score MD 4.95% CI 0.9). Those satisfying the new definition also had a greater number of tender points on examination (MD 3.95% CI -1.7). The morbidity of those satisfying only the present ACR definition was closer to persons who had regional pain. A redefinition of widespread pain has produced a group of subjects whose pain is (a) likely to be more "widespread" and (b) is associated more strongly with factors such as psychological disturbance, fatigue, sleep problems, and tender points, and may be more appropriate in epidemiological studies.

Central sensitization: a biopsychosocial explanation for chronic widespread pain in patients with fibromyalgia and chronic fatigue syndrome

PubMed Central

Meeus, Mira

2006-01-01

In addition to the debilitating fatigue, the majority of patients with chronic fatigue syndrome (CFS) experience chronic widespread pain. These pain complaints show the greatest overlap between CFS and fibromyalgia (FM). Although the literature provides evidence for central sensitization as cause for the musculoskeletal pain in FM, in CFS this evidence is currently lacking, despite the observed similarities in both diseases. The knowledge concerning the physiological mechanism of central sensitization, the pathophysiology and the pain processing in FM, and the knowledge on the pathophysiology of CFS lead to the hypothesis that central sensitization is also responsible for the sustaining pain complaints in CFS. This hypothesis is based on the hyperalgesia and allodynia reported in CFS, on the elevated concentrations of nitric oxide presented in the blood of CFS patients, on the typical personality styles seen in CFS and on the brain abnormalities shown on brain images. To examine the present hypothesis more research is required. Further investigations could use similar protocols to those already used in studies on pain in FM like, for example, studies on temporal summation, spatial summation, the role of psychosocial aspects in chronic pain, etc. PMID:17115100

Effects of a resistance training program on balance and fatigue perception in patients with Parkinson's disease: A randomized controlled trial.

PubMed

Ortiz-Rubio, Araceli; Cabrera-Martos, Irene; Torres-Sánchez, Irene; Casilda-López, Jesús; López-López, Laura; Valenza, Marie Carmen

2017-11-22

Fatigue and balance impairment leads to a loss of independence and are important to adequately manage. The objective of this study was to examine the effects of a resistance training program on dynamic balance and fatigue in patients with Parkinson's disease (PD). Randomized controlled trial. Forty-six patients with PD were randomly allocated to an intervention group receiving a 8-week resistance training program focused on lower limbs or to a control group. Balance was assessed using the Mini-BESTest and fatigue was assessed by the Piper Fatigue Scale. Patients in the intervention group improved significantly (p<0.05) on dynamic balance (reactive postural control and total values) and perceived fatigue. An 8-week resistance training program was found to be effective at improving dynamic balance and fatigue in patients with PD. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

A Practical Engineering Approach to Predicting Fatigue Crack Growth in Riveted Lap Joints

NASA Technical Reports Server (NTRS)

Harris, Charles E.; Piascik, Robert S.; Newman, James C., Jr.

1999-01-01

An extensive experimental database has been assembled from very detailed teardown examinations of fatigue cracks found in rivet holes of fuselage structural components. Based on this experimental database, a comprehensive analysis methodology was developed to predict the onset of widespread fatigue damage in lap joints of fuselage structure. Several computer codes were developed with specialized capabilities to conduct the various analyses that make up the comprehensive methodology. Over the past several years, the authors have interrogated various aspects of the analysis methods to determine the degree of computational rigor required to produce numerical predictions with acceptable engineering accuracy. This study led to the formulation of a practical engineering approach to predicting fatigue crack growth in riveted lap joints. This paper describes the practical engineering approach and compares predictions with the results from several experimental studies.

A Practical Engineering Approach to Predicting Fatigue Crack Growth in Riveted Lap Joints

NASA Technical Reports Server (NTRS)

Harris, C. E.; Piascik, R. S.; Newman, J. C., Jr.

2000-01-01

An extensive experimental database has been assembled from very detailed teardown examinations of fatigue cracks found in rivet holes of fuselage structural components. Based on this experimental database, a comprehensive analysis methodology was developed to predict the onset of widespread fatigue damage in lap joints of fuselage structure. Several computer codes were developed with specialized capabilities to conduct the various analyses that make up the comprehensive methodology. Over the past several years, the authors have interrogated various aspects of the analysis methods to determine the degree of computational rigor required to produce numerical predictions with acceptable engineering accuracy. This study led to the formulation of a practical engineering approach to predicting fatigue crack growth in riveted lap joints. This paper describes the practical engineering approach and compares predictions with the results from several experimental studies.

A data acquisition and control program for axial-torsional fatigue testing

NASA Technical Reports Server (NTRS)

Kalluri, Sreeramesh; Bonacuse, Peter J.

1989-01-01

A computer program was developed for data acquisition and control of axial-torsional fatigue experiments. The multitasked, interrupt-driven program was written in Pascal and Assembly. This program is capable of dual-channel control and six-channel data acquisition. It can be utilized to perform inphase and out-of-phase axial-torsional isothermal fatigue or deformation experiments. The program was successfully used to conduct inphase axial-torsional fatigue experiments on 304 stainless steel at room temperature and on Hastelloy X at 800 C. The details of the software and some of the results generated to date are presented.

Novel approach of wavelet analysis for nonlinear ultrasonic measurements and fatigue assessment of jet engine components

NASA Astrophysics Data System (ADS)

Bunget, Gheorghe; Tilmon, Brevin; Yee, Andrew; Stewart, Dylan; Rogers, James; Webster, Matthew; Farinholt, Kevin; Friedersdorf, Fritz; Pepi, Marc; Ghoshal, Anindya

2018-04-01

Widespread damage in aging aircraft is becoming an increasing concern as both civil and military fleet operators are extending the service lifetime of their aircraft. Metallic components undergoing variable cyclic loadings eventually fatigue and form dislocations as precursors to ultimate failure. In order to characterize the progression of fatigue damage precursors (DP), the acoustic nonlinearity parameter is measured as the primary indicator. However, using proven standard ultrasonic technology for nonlinear measurements presents limitations for settings outside of the laboratory environment. This paper presents an approach for ultrasonic inspection through automated immersion scanning of hot section engine components where mature ultrasonic technology is used during periodic inspections. Nonlinear ultrasonic measurements were analyzed using wavelet analysis to extract multiple harmonics from the received signals. Measurements indicated strong correlations of nonlinearity coefficients and levels of fatigue in aluminum and Ni-based superalloys. This novel wavelet cross-correlation (WCC) algorithm is a potential technique to scan for fatigue damage precursors and identify critical locations for remaining life prediction.

Advances in Fatigue and Fracture Mechanics Analyses for Aircraft Structures

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.

1999-01-01

This paper reviews some of the advances that have been made in stress analyses of cracked aircraft components, in the understanding of the fatigue and fatigue-crack growth process, and in the prediction of residual strength of complex aircraft structures with widespread fatigue damage. Finite-element analyses of cracked structures are now used to determine accurate stress-intensity factors for cracks at structural details. Observations of small-crack behavior at open and rivet-loaded holes and the development of small-crack theory has lead to the prediction of stress-life behavior for components with stress concentrations under aircraft spectrum loading. Fatigue-crack growth under simulated aircraft spectra can now be predicted with the crack-closure concept. Residual strength of cracked panels with severe out-of-plane deformations (buckling) in the presence of stiffeners and multiple-site damage can be predicted with advanced elastic-plastic finite-element analyses and the critical crack-tip-opening angle (CTOA) fracture criterion. These advances are helping to assure continued safety of aircraft structures.

Advances in Fatigue and Fracture Mechanics Analyses for Metallic Aircraft Structures

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.

2000-01-01

This paper reviews some of the advances that have been made in stress analyses of cracked aircraft components, in the understanding of the fatigue and fatigue-crack growth process, and in the prediction of residual strength of complex aircraft structures with widespread fatigue damage. Finite-element analyses of cracked metallic structures are now used to determine accurate stress-intensity factors for cracks at structural details. Observations of small-crack behavior at open and rivet-loaded holes and the development of small-crack theory has lead to the prediction of stress-life behavior for components with stress concentrations under aircraft spectrum loading. Fatigue-crack growth under simulated aircraft spectra can now be predicted with the crack-closure concept. Residual strength of cracked panels with severe out-of-plane deformations (buckling) in the presence of stiffeners and multiple-site damage can be predicted with advanced elastic-plastic finite-element analyses and the critical crack-tip-opening angle (CTOA) fracture criterion. These advances are helping to assure continued safety of aircraft structures.

Cancer-related fatigue management: evaluation of a patient education program with a large-scale randomised controlled trial, the PEPs fatigue study.

PubMed

Bourmaud, A; Anota, A; Moncharmont, C; Tinquaut, F; Oriol, M; Trillet-Lenoir, V; Bajard, A; Parnalland, S; Rotonda, C; Bonnetain, F; Pérol, D; Chauvin, F

2017-03-28

To assess the efficacy of a patient educational program built according to guidelines that aims at reducing cancer-related fatigue (CRF). Randomised controlled trial, multicentre, comparing a patient education program, vs the standard of care. Patients were adult cancer outpatients with any tumour site. The primary outcome was fatigue severity assessed with a visual analogical scale (VAS), between the day of randomisation and week 7. Secondary outcomes were fatigue assessed with other scales, health-related quality of life, anxiety and depression. The time to fatigue severity deterioration was assessed. Analyses were performed in a modified intent-to-treat way, that is, including all patients with at least one baseline and 1 week 7 score. A total of 212 patients were included. Fatigue severity assessment was made on 79 patients in the experimental group and 65 in the control group. Between randomisation and week 7, the fatigue (VAS) improved by 0.96 (2.85) points in the experimental group vs 1.63 (2.63) points in the control group (P=0.15). No differences with the secondary outcomes were highlighted between two groups. No other factors were found to be associated with fatigue severity deterioration. Despite rigorous methodology, this study failed to highlight the program efficacy in fatigue reduction for cancer patients. Other assessment tools should be developed to measure the effect of the program on CRF and behaviour. The implementation of the program should also be explored in order to identify its mechanisms and longer-term impact.

Cancer-related fatigue management: evaluation of a patient education program with a large-scale randomised controlled trial, the PEPs fatigue study

PubMed Central

Bourmaud, A; Anota, A; Moncharmont, C; Tinquaut, F; Oriol, M; Trillet-Lenoir, V; Bajard, A; Parnalland, S; Rotonda, C; Bonnetain, F; Pérol, D; Chauvin, F

2017-01-01

Background: To assess the efficacy of a patient educational program built according to guidelines that aims at reducing cancer-related fatigue (CRF). Methods: Randomised controlled trial, multicentre, comparing a patient education program, vs the standard of care. Patients were adult cancer outpatients with any tumour site. The primary outcome was fatigue severity assessed with a visual analogical scale (VAS), between the day of randomisation and week 7. Secondary outcomes were fatigue assessed with other scales, health-related quality of life, anxiety and depression. The time to fatigue severity deterioration was assessed. Analyses were performed in a modified intent-to-treat way, that is, including all patients with at least one baseline and 1 week 7 score. Results: A total of 212 patients were included. Fatigue severity assessment was made on 79 patients in the experimental group and 65 in the control group. Between randomisation and week 7, the fatigue (VAS) improved by 0.96 (2.85) points in the experimental group vs 1.63 (2.63) points in the control group (P=0.15). No differences with the secondary outcomes were highlighted between two groups. No other factors were found to be associated with fatigue severity deterioration. Conclusions: Despite rigorous methodology, this study failed to highlight the program efficacy in fatigue reduction for cancer patients. Other assessment tools should be developed to measure the effect of the program on CRF and behaviour. The implementation of the program should also be explored in order to identify its mechanisms and longer-term impact. PMID:28196066

A Framework for Fibromyalgia Management for Primary Care Providers

PubMed Central

Arnold, Lesley M.; Clauw, Daniel J.; Dunegan, L. Jean; Turk, Dennis C.

2012-01-01

Fibromyalgia is a chronic widespread pain disorder commonly associated with comorbid symptoms, including fatigue and nonrestorative sleep. As in the management of other chronic medical disorders, the approach for fibromyalgia management follows core principles of comprehensive assessment, education, goal setting, multimodal treatment including pharmacological (eg, pregabalin, duloxetine, milnacipran) and nonpharmacological therapies (eg, physical activity, behavioral therapy, sleep hygiene, education), and regular education and monitoring of treatment response and progress. Based on these core management principles, this review presents a framework for primary care providers through which they can develop a patient-centered treatment program for patients with fibromyalgia. This proactive and systematic treatment approach encourages ongoing education and patient self-management and is designed for use in the primary care setting. PMID:22560527

A multicenter randomized controlled trial of two group education programs for fatigue in multiple sclerosis: Long-term (12-month) follow-up at one site.

PubMed

Hugos, Cinda L; Cameron, Michelle H; Chen, Zunqiu; Chen, Yiyi; Bourdette, Dennis

2018-05-01

A four-site RCT of Fatigue: Take Control (FTC), a multicomponent group program, found no significant differences from a control program, MS: Take Control (MSTC), in fatigue on the Modified Fatigue Impact Scale (MFIS) through 6 months. Assess FTC for a delayed effect on fatigue. Of 78 subjects at one site, 74 randomized to FTC or MSTC completed the MFIS at 12 months. Compared to baseline, FTC produced greater improvements in MFIS scores than MSTC (FTC -8.9 (confidence interval (CI): 32.2, 45), MSTC -2.5 (CI 39.6, 47.7), p = 0.03) at 12 months. The delayed effect of FTC on fatigue suggests the need for longer follow-up when assessing interventions for fatigue.

Fatigue-enhanced hyperalgesia in response to muscle insult: induction and development occur in a sex-dependent manner

PubMed Central

Gregory, N. S.; Gibson-Corley, K.; Frey-Law, L.; Sluka, K. A.

2014-01-01

Chronic muscle pain affects 20–50% of the population, is more common in women than men, and is associated with increased pain during physical activity and exercise. Muscle fatigue is common in people with chronic muscle pain, occurs in response to exercise and is associated with release of fatigue metabolites. Fatigue metabolites can sensitize muscle nociceptors which could enhance pain with exercise. Using a mouse model we tested whether fatigue of a single muscle, induced by electrical stimulation, resulted in enhanced muscle hyperalgesia and if the enhanced hyperalgesia was more pronounced in female mice. Muscle fatigue was induced in combination with a sub-threshold muscle insult (2 injections of pH 5.0 saline) in male and female mice. We show that male and female mice, fatigued immediately prior to muscle insult in the same muscle, develop similar muscle hyperalgesia 24h later. However, female mice also develop hyperalgesia when muscle fatigue and muscle insult occur in different muscles, and when muscle insult is administered 24 hours after fatigue in the same muscle. Further, hyperalgesia lasts significantly longer in females. Finally, muscle insult with or without muscle fatigue results in minimal inflammatory changes in the muscle itself, and sex differences are not related to estradiol (ovariectomy) or changes in brainstem activity (pNR1). Thus, the current model mimics muscle fatigue-induced enhancement of pain observed in chronic muscle pain conditions in the human population. Interactions between fatigue and muscle insult may underlie the development of chronic widespread pain with an associated female predominance observed in human subjects. PMID:23906552

Protocol for the "four steps to control your fatigue (4-STEPS)" randomised controlled trial: a self-regulation based physical activity intervention for patients with unexplained chronic fatigue

PubMed Central

2012-01-01

Background Unexplained Chronic Fatigue is a medical condition characterized by the presence of persistent, severe and debilitating medically unexplained fatigue, leading to impaired functioning and lower quality of life. Research suggests that physical activity can contribute to the reduction of fatigue and other somatic symptoms and can thus significantly improve physical functioning and quality of life in these patients. Based on the self-regulation (SR) theory of behaviour change, we developed a brief physical activity program for patients suffering from unexplained chronic fatigue which focuses on the training of self-regulation skills, the "4-STEPS to control your fatigue" program. Methods/Design This is a multi-centre, randomised controlled trial (RCT) that will be carried out in local primary care centres and at the Portuguese Fibromyalgia and Chronic Fatigue Syndrome Patients Association. Patients aged between 18 and 65 and fulfilling operationalized criteria for Idiopathic Chronic Fatigue (ICF) and Chronic Fatigue Syndrome (CFS) will be recruited and randomly allocated to standard care (SC) or standard care plus a self-regulation based physical activity program (4-STEPS). Patients will be assessed at baseline, after the intervention (3 months) and at 12 months follow-up. The primary outcome is fatigue severity. Discussion The results of the RCT will provide information about the effectiveness of a brief self-regulation intervention for promoting physical activity in patients with unexplained chronic fatigue. If the program proves to be effective, it may be considered as an adjunctive treatment for these patients. Trial Registration ISRCTN: ISRCTN70763996 PMID:22429404

Fatigue Countermeasures: Alertness Management in Flight Operations

NASA Technical Reports Server (NTRS)

Co, E. L.; Rosekind, M. R.; Johnson, J. M.; Weldon, K. J.; Smith, R. M.; Gregory, K. G.; Miller, D. L.; Gander, P. H.; Lebacqz, J. V.; Statler, Irving C. (Technical Monitor)

1994-01-01

Since 1980, the NASA Ames Fatigue Countermeasures Program has studied the effects and impact of fatigue on flight operations . Sleep loss and circadian disruption are two of the primary physiological factors that underlie fatigue in flight operations. The Program has developed an array of fatigue countermeasure recommendations that can be used to combat the effects of fatigue and continues to research potential new countermeasures. For example, one such strategy involved a NASA/FAA study on the effects of planned cockpit rest to improve crewmember alertness and performance. Based partly on the study results, the FAA is currently reviewing a proposed Advisory Circular for controlled rest on the flight deck. Since there is no simple answer to the issue of fatigue in aviation, an Education and Training Module has been developed to provide the industry with pertinent information on sleep, circadian rhythms, how flight operations affect these physiological factors, and recommendations for fatigue countermeasures. The Module will be updated as the Program's continued research efforts uncover new information and develop new countermeasure strategies,

A randomized controlled trial of qigong exercise on fatigue symptoms, functioning, and telomerase activity in persons with chronic fatigue or chronic fatigue syndrome.

PubMed

Ho, Rainbow T H; Chan, Jessie S M; Wang, Chong-Wen; Lau, Benson W M; So, Kwok Fai; Yuen, Li Ping; Sham, Jonathan S T; Chan, Cecilia L W

2012-10-01

Chronic fatigue is common in the general population. Complementary therapies are often used by patients with chronic fatigue or chronic fatigue syndrome to manage their symptoms. This study aimed to assess the effect of a 4-month qigong intervention program among patients with chronic fatigue or chronic fatigue syndrome. Sixty-four participants were randomly assigned to either an intervention group or a wait list control group. Outcome measures included fatigue symptoms, physical functioning, mental functioning, and telomerase activity. Fatigue symptoms and mental functioning were significantly improved in the qigong group compared to controls. Telomerase activity increased in the qigong group from 0.102 to 0.178 arbitrary units (p < 0.05). The change was statistically significant when compared to the control group (p < 0.05). Qigong exercise may be used as an alternative and complementary therapy or rehabilitative program for chronic fatigue and chronic fatigue syndrome.

Fatigue and post-fatigue performance of Fabry-Perot FOS installed on CFRP-strengthened RC-beams

NASA Astrophysics Data System (ADS)

Gheorghiu, Catalin; Labossiere, Pierre; Proulx, Jean

2004-07-01

There is a growing need for built-in monitoring systems for civil engineering infrastructures, due to problems such as increasing traffic loads and rising costs of maintenance and repair. Fibre optic sensors (FOS), capable of reading various parameters are promising candidates for life-long health monitoring of these structures. However, since FOS have only been introduced recently into the field of structural monitoring, their acceptance and widespread implementation will be conditioned by their durability under severe climatic and loading conditions. This paper reports on the performance of strain extrinsic FOS attached to carbon fibre reinforced polymer (CFRP) plates used to strengthen concrete structures. The specimens tested in this project are reinforced concrete (RC) beams with an additional external CFRP reinforcement. The FOS-instrumented beams were first subjected to fatigue loading for various numbers of cycles and load amplitudes. Then, they were tested monotonically to failure under four-point-bending. The test results provide an insight on the fatigue and post-fatigue behaviour of FOS used for monitoring reinforced concrete structures.

FLAPS (Fatigue Life Analysis Programs): Computer Programs to Predict Cyclic Life Using the Total Strain Version of Strainrange Partitioning and Other Life Prediction Methods. Users' Manual and Example Problems, Version 1.0

NASA Technical Reports Server (NTRS)

Arya, Vinod K.; Halford, Gary R. (Technical Monitor)

2003-01-01

This manual presents computer programs FLAPS for characterizing and predicting fatigue and creep-fatigue resistance of metallic materials in the high-temperature, long-life regime for isothermal and nonisothermal fatigue. The programs use the Total Strain version of Strainrange Partitioning (TS-SRP), and several other life prediction methods described in this manual. The user should be thoroughly familiar with the TS-SRP and these life prediction methods before attempting to use any of these programs. Improper understanding can lead to incorrect use of the method and erroneous life predictions. An extensive database has also been developed in a parallel effort. The database is probably the largest source of high-temperature, creep-fatigue test data available in the public domain and can be used with other life-prediction methods as well. This users' manual, software, and database are all in the public domain and can be obtained by contacting the author. The Compact Disk (CD) accompanying this manual contains an executable file for the FLAPS program, two datasets required for the example problems in the manual, and the creep-fatigue data in a format compatible with these programs.

[Development and Application of an Overcoming Compassion Fatigue Program for Emergency Nurses].

PubMed

Kim, Yeong Ah; Park, Jeong Sook

2016-04-01

This study was conducted to develop a program to help emergency nurses overcome compassion fatigue, and to analyze the effects of the program. A nonequivalent control group pretest-posttest design was used. There were 14 participants in the experimental group and 18 subjects in the control group. The program was comprised of five, weekly 80-minute sessions including understanding and assessment of compassion fatigue, enhancing positive affect, balancing work-life, planning self care, training in relaxation techniques and cognitive restructuring, and getting social support. Research variables were ego-resiliency, compassion satisfaction and compassion fatigue of the ProQOL 5, and salivary cortisol. Data were analyzed using Chi-square test, independent t-test, and paired t-test. The first hypothesis, "There will be a difference in scores for ego resiliency between the experimental group and the control group". was not supported. The second hypothesis, "There will be a difference in scores for compassion satisfaction between the experimental group and the control group" was supported (t=2.15, p=.046). The third hypothesis, "There will be a difference in scores for compassion fatigue between the experimental group and the control group" was not supported. The first program for emergency nurses to overcome compassion fatigue in Korea was effective in increasing emergency nurses' compassion satisfaction and decreasing salivary cortisol level in the experimental group. Therefore, this program for overcoming compassion fatigue is useful to increase emergency nurses' compassion satisfaction. However replication studies of short-term intensive program reflecting emergency nurses' opinion are needed.

Central Mechanisms in the Maintenance of Chronic Widespread Noninflammatory Muscle Pain

PubMed Central

DeSantana, Josimari M.; Sluka, Kathleen A.

2009-01-01

Chronic widespread pain (CWP) conditions such as fibromyalgia and myofascial syndromes are characterized by generalized pain, tenderness, morning stiffness, disturbed sleep, and pronounced fatigue. However, CWP pathophysiology is still unclear. A number of hypotheses have been proposed as the underlying pathophysiology of CWP: muscular dysfunction/ischemia, central sensitization, and a deficit in endogenous pain-modulating systems. This article reviews the current and emerging literature about the pathophysiology and neurobiology of chronic widespread musculoskeletal pain. Widespread musculoskeletal pain results in changes in the central nervous system in human subjects and animal models. These changes likely reflect alterations in supraspinal modulation of nociception, and include increases in excitatory and decreases in inhibitory modulation pathways. These alterations in excitation and inhibition likely drive changes observed in the spinal cord to result in central sensitization, and the consequent pain and hyperalgesia. PMID:18765138

A Review of Fatigue Crack Growth for Pipeline Steels Exposed to Hydrogen

PubMed Central

Nanninga, N.; Slifka, A.; Levy, Y.; White, C.

2010-01-01

Hydrogen pipeline systems offer an economical means of storing and transporting energy in the form of hydrogen gas. Pipelines can be used to transport hydrogen that has been generated at solar and wind farms to and from salt cavern storage locations. In addition, pipeline transportation systems will be essential before widespread hydrogen fuel cell vehicle technology becomes a reality. Since hydrogen pipeline use is expected to grow, the mechanical integrity of these pipelines will need to be validated under the presence of pressurized hydrogen. This paper focuses on a review of the fatigue crack growth response of pipeline steels when exposed to gaseous hydrogen environments. Because of defect-tolerant design principles in pipeline structures, it is essential that designers consider hydrogen-assisted fatigue crack growth behavior in these applications. PMID:27134796

Frequency of fibromyalgia syndrome in breast cancer patients.

PubMed

Akkaya, Nuray; Atalay, Nilgün Simsir; Selcuk, Selin Taflan; Alkan, Hakan; Catalbas, Necdet; Sahin, Füsun

2013-04-01

We aimed to determine the frequency of fibromyalgia syndrome (FM) in operated breast cancer patients and to research the relationship between FM and the severity of fatigue and quality of life in these breast cancer patients. The demographic data of 101 operated breast cancer patients were recorded. The patients who had pain were then classified as having regional pain (RP), widespread pain without FM (WP), and widespread pain with FM (WFM). The FM diagnosis was based on the American College of Rheumatology (ACR) criteria. The severity of fatigue was evaluated with the Brief Fatigue Inventory, the disease impact was evaluated with the Fibromyalgia Impact Questionnaire (FIQ), and the quality of life was evaluated with the European Organization for Research on Treatment of Cancer questionnaire Quality of Life-C30 (EORTC-QoL-C30). There was no pain in 38 (37.6%) patients, whereas there was pain in 63 (62.4%) patients (N = 42, 41.6% had RP, N = 21, 20.8% had WP). Ten (9.9%) of the entire patient cohort were diagnosed as having FM according to the ACR criteria. There were no differences among the 3 groups in respect to demographic characteristics when patients were classified as RP (N = 42), WP (N = 11), and WFM (N = 10) groups. While there were negative correlations between the FIQ and EORTC-QoL-C30-function score (r = -0.727) and EORTC-QoL-C30-global score (r = -0.488), there was a positive correlation between the FIQ and EORTC-QoL-C30-symptom score (r = 0.726). We note that the frequency of FM in the operated breast cancer patients in this study was higher than that reported in normal populations in the literature. Also, we found that the presence of FM had negative effects on the quality of life of the breast cancer patients. Accordingly, in the evaluation of widespread pain and complaints of fatigue in long-surviving breast cancer patients, after metastatic disease is excluded, the probability of FM should be kept in mind, so that appropriate treatment can be initiated to improve their functional status and quality of life.

Fatigue strength reduction model: RANDOM3 and RANDOM4 user manual. Appendix 2: Development of advanced methodologies for probabilistic constitutive relationships of material strength models

NASA Technical Reports Server (NTRS)

Boyce, Lola; Lovelace, Thomas B.

1989-01-01

FORTRAN programs RANDOM3 and RANDOM4 are documented in the form of a user's manual. Both programs are based on fatigue strength reduction, using a probabilistic constitutive model. The programs predict the random lifetime of an engine component to reach a given fatigue strength. The theoretical backgrounds, input data instructions, and sample problems illustrating the use of the programs are included.

14 CFR 26.5 - Applicability table.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Applicability table. 26.5 Section 26.5... AIRWORTHINESS AND SAFETY IMPROVEMENTS FOR TRANSPORT CATEGORY AIRPLANES General § 26.5 Applicability table. Table... Subpart B EAPAS/FTS Subpart C widespread fatigue damage Subpart D fuel tankflammability Subpart E...

14 CFR 26.5 - Applicability table.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Applicability table. 26.5 Section 26.5... AIRWORTHINESS AND SAFETY IMPROVEMENTS FOR TRANSPORT CATEGORY AIRPLANES General § 26.5 Applicability table. Table... Subpart B EAPAS/FTS Subpart C widespread fatigue damage Subpart D fuel tankflammability Subpart E...

14 CFR 26.5 - Applicability table.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Applicability table. 26.5 Section 26.5... AIRWORTHINESS AND SAFETY IMPROVEMENTS FOR TRANSPORT CATEGORY AIRPLANES General § 26.5 Applicability table. Table... Subpart B EAPAS/FTS Subpart C widespread fatigue damage Subpart D fuel tankflammability Subpart E...

Computer programs to characterize alloys and predict cyclic life using the total strain version of strainrange partitioning: Tutorial and users manual, version 1.0

NASA Technical Reports Server (NTRS)

Saltsman, James F.

1992-01-01

This manual presents computer programs for characterizing and predicting fatigue and creep-fatigue resistance of metallic materials in the high-temperature, long-life regime for isothermal and nonisothermal fatigue. The programs use the total strain version of Strainrange Partitioning (TS-SRP). An extensive database has also been developed in a parallel effort. This database is probably the largest source of high-temperature, creep-fatigue test data available in the public domain and can be used with other life prediction methods as well. This users manual, software, and database are all in the public domain and are available through COSMIC (382 East Broad Street, Athens, GA 30602; (404) 542-3265, FAX (404) 542-4807). Two disks accompany this manual. The first disk contains the source code, executable files, and sample output from these programs. The second disk contains the creep-fatigue data in a format compatible with these programs.

The NASA Ames Fatigue Countermeasures Program: The Next Generation

NASA Technical Reports Server (NTRS)

Rosekind, Mark R.; Neri, David F.; Miller, Donna L.; Gregory, Kevin B.; Webbon, Lissa L.; Oyung, Ray L.

1997-01-01

Twenty-four hour, global aviation operations pose unique challenges to humans. Physiological requirements related to sleep, the internal circadian clock, and human fatigue are critical factors that are known to affect safety, performance, and productivity. Understanding the human operators' physiological capabilities, and limitations, will be important to address these issues as global demand for aviation activities continues to increase. In 1980, in response to a Congressional request, the National Aeronautics and Space Administration (NASA) Ames Research Center initiated a Fatigue/Jet Lag Program to examine the role of fatigue in flight operations. Originally established by Dr. John K. Lauber and Dr. Charles E. Billings, the Program was designed to address three objectives: (1) determine the extent of fatigue, sleep loss, and circadian disruption in flight operations; (2) determine how fatigue affected flight crew performance; and (3) develop strategies to maximize performance and alertness during flight operations.

A proposed USAF fatigue evaluation program based upon recent systems experience

NASA Technical Reports Server (NTRS)

Haviland, G. P.; Purkey, G. F.

1972-01-01

The United States Air Force has published a document entitled Aircraft Structural Integrity Program. One phase of the program is concerned with the fatigue life certification of all types of military aircraft. The document describes the criteria, analyses, and tests that are necessary in order to satisfy the USAF fatigue life requirement. Some recent and valid criticism has been directed toward the document, particularly the fatigue-life requirements contained in it. Some changes are proposed based on surveys conducted in the United States and abroad as well as some recent systems' experience. The surveys covered both military and civilian organizations. The fatigue certification case histories of selected military and commercial aircraft are presented. The design development element tests, preproduction design verification tests, and full-scale fatigue tests of each are described. A brief status report on the revisions to the MIL-A-008860 series specifications is included.

Feasibility of a Telehealth Educational Program on Self-Management of Pain and Fatigue in Adult Cancer Patients.

PubMed

Rocque, Gabrielle B; Halilova, Karina I; Varley, Allyson L; Williams, Courtney P; Taylor, Richard A; Masom, David G; Wright, William J; Partridge, Edward E; Kvale, Elizabeth A

2017-06-01

Pain and fatigue are common symptoms among cancer patients and often lead to substantial distress. Innovative self-management programs for pain and fatigue are needed. The primary objective was to assess the feasibility of a telehealth pain and fatigue self-management program among adult cancer patients. Secondary objectives included assessment of differences in patient characteristics, recruitment, and retention of patients based on two screening strategies: 1) navigator-collected, patient-reported pain or fatigue and 2) in-clinic, physician-identified pain or fatigue. This prospective, nonrandomized, pre-post evaluation assessed feasibility, which was defined as 50% of eligible patients choosing to participate and completing the intervention. Patient demographics and patient-reported outcomes (patient activation, distress, symptoms, and quality of life) were collected at baseline and study completion. Differences in baseline characteristics were compared between cohorts and for patients who did vs. did not graduate from the program. The program did not meet feasibility requirements because of only 34% of eligible patients choosing to participate. However, 50% of patients starting the program graduated. Differences in baseline characteristics and retention rates were noted by recruitment strategy. At baseline, 27.3% of navigated patients were at the highest activation level compared with 7.1% in the physician-referred, non-navigated patients (P = 0.17); more than 15% of non-completers were at the lowest activation level compared with 9% of completers (P = 0.85). Telehealth self-management program for pain and fatigue may be better accepted among selected segments of cancer patients. Larger scale studies are needed to assess the efficacy of this program in a more selective activated population. Copyright © 2017 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

Clinical Manifestation and a New "ISCU" Mutation in Iron-Sulphur Cluster Deficiency Myopathy

ERIC Educational Resources Information Center

Kollberg, Gittan; Tulinius, Mar; Melberg, Atle; Darin, Niklas; Andersen, Oluf; Holmgren, Daniel; Oldfors, Anders; Holme, Elisabeth

2009-01-01

Myopathy with deficiency of succinate dehydrogenase and aconitase is a recessively inherited disorder characterized by childhood-onset early fatigue, dyspnoea and palpitations on trivial exercise. The disease is non-progressive, but life-threatening episodes of widespread weakness, severe metabolic acidosis and rhabdomyolysis may occur. The…

Microstructure, Fatigue Behavior, and Failure Mechanisms of Direct Laser-Deposited Inconel 718

NASA Astrophysics Data System (ADS)

Johnson, Alex S.; Shao, Shuai; Shamsaei, Nima; Thompson, Scott M.; Bian, Linkan

2017-03-01

Inconel 718 is considered to be a superalloy with a series of superior properties such as high strength, creep resistance, and corrosion resistance at room and elevated temperatures. Additive manufacturing (AM) is particularly appealing to Inconel 718 because of its near-net-shape production capability for circumventing the poor machinability of this superalloy. Nevertheless, AM parts are prone to porosity, which is detrimental to their fatigue resistance. Thus, further understanding of their fatigue behavior is required before their widespread use in load-bearing applications. In this work, the microstructure and fatigue properties of AM Inconel 718, produced in a Laser Engineered Net Shaping (LENS™) system and heat treated with a standard heat treatment schedule, are evaluated at room temperature. Fully reversed strain controlled fatigue tests were performed on cylindrical specimens with straight gage sections at strain amplitudes ranging from 0.001 mm/mm to 0.01 mm/mm. The fracture surfaces of fatigue specimens were inspected with a scanning electron microscope. The results indicate that the employed heat treatment allowed the large, elongated grains and dendritic structure of the as-built material to break down into smaller, equiaxed grains, with some dendritic structures remaining between layers. The AM specimens were found to possess lower fatigue resistance than wrought Inconel 718, and this is primarily attributed to the presence of brittle metal-carbide/oxide inclusions or pores near their surface.

Using Wii Fit to reduce fatigue among African American women with systemic lupus erythematosus: a pilot study.

PubMed

Yuen, H K; Holthaus, K; Kamen, D L; Sword, D O; Breland, H L

2011-10-01

Fatigue and physical deconditioning are common, difficult to treat conditions among patients with systemic lupus erythematosus (SLE). The aim of this pilot study was to evaluate the effectiveness of a home-based exercise program using the Wii Fit system in patients with SLE. Fifteen sedentary African American women with SLE experiencing moderate to severe fatigue participated in a home exercise program using the Wii Fit 3 days a week for 30 minutes each for 10 weeks. A one-group pretest-post test design was used to evaluate the effectiveness of this program. Primary outcome measure was severity of fatigue. Secondary outcome measures were body weight, waist circumference, fatigue-related symptoms of distress, activity level, and physical fitness. At the completion of the 10-week Wii Fit exercise program, participants perceived fatigue severity as measured by the Fatigue Severity Scale to be significantly decreased (p = 0.002), and body weight and waist circumference were significantly reduced (p = 0.01). In addition, anxiety level, as measured by Hospital Anxiety and Depression Scale, and overall intensity of total pain experience, as measured by Short-form of the McGill Pain Questionnaire, were also significantly reduced (p < 0.05). Findings provide preliminary evidence that the Wii Fit motivates this population to exercise, which leads to alleviation of fatigue and reduced body weight, waist circumference, anxiety level, and overall intensity of total pain experience.

Using Wii Fit to reduce fatigue among African American women with systemic lupus erythematosus: A pilot study

PubMed Central

Yuen, Hon K.; Holthaus, Katy; Kamen, Diane L.; Sword, David; Breland, Hazel L.

2012-01-01

Fatigue and physical deconditioning are common, difficult to treat conditions among patients with systemic lupus erythematosus (SLE). The aim of this pilot study is to evaluate the effectiveness of a home-based exercise program using the Wii Fit system in patients with SLE. Fifteen sedentary African American women with SLE experiencing moderate to severe fatigue participated in a home exercise program using the Wii Fit 3 days a week for 30 minutes each for 10 weeks. A one-group pretest-posttest design was used to evaluate the effectiveness of this program. Primary outcome measure was severity of fatigue. Secondary outcome measures were body weight, waist circumference, fatigue-related symptoms of distress, activity level and physical fitness. At the completion of the 10-week Wii Fit exercise program, participants perceived fatigue severity as measured by the Fatigue Severity Scale to be significantly decreased (P=0.002), body weight and waist circumference were significantly reduced (Ps=0.01). In addition, anxiety level as measured by Hospital Anxiety and Depression Scale, and overall intensity of total pain experience as measured by Short-form of the McGill Pain Questionnaire were also significantly reduced (Ps<0.05). Findings provide preliminary support that the Wii Fit motivates this population to exercise which leads to alleviation of fatigue and reduced body weight, waist circumference, anxiety level, and overall intensity of total pain experience. PMID:21700656

Improving Fatigue Performance of AHSS Welds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Zhili; Yu, Xinghua; Erdman, III, Donald L.

Reported herein is technical progress on a U.S. Department of Energy CRADA project with industry cost-share aimed at developing the technical basis and demonstrate the viability of innovative in-situ weld residual stresses mitigation technology that can substantially improve the weld fatigue performance and durability of auto-body structures. The developed technology would be costeffective and practical in high-volume vehicle production environment. Enhancing weld fatigue performance would address a critical technology gap that impedes the widespread use of advanced high-strength steels (AHSS) and other lightweight materials for auto body structure light-weighting. This means that the automotive industry can take full advantage ofmore » the AHSS in strength, durability and crashworthiness without the concern of the relatively weak weld fatigue performance. The project comprises both technological innovations in weld residual stress mitigation and due-diligence residual stress measurement and fatigue performance evaluation. Two approaches were investigated. The first one was the use of low temperature phase transformation (LTPT) weld filler wire, and the second focused on novel thermo-mechanical stress management technique. Both technical approaches have resulted in considerable improvement in fatigue lives of welded joints made of high-strength steels. Synchrotron diffraction measurement confirmed the reduction of high tensile weld residual stresses by the two weld residual stress mitigation techniques.« less

Modafinil treatment for fatigue in HIV+ patients: a pilot study.

PubMed

Rabkin, Judith G; McElhiney, Martin C; Rabkin, Richard; Ferrando, Stephen J

2004-12-01

Fatigue is widespread among human immunodeficiency virus-positive (HIV+) patients, yet few studies have assessed effective treatments. The authors conducted a pilot study to evaluate the efficacy of modafinil for fatigue in this clinical population. Response was evaluated after a 4-week open-label trial. Data were collected from February 2003 through January 2004. Responders were offered 8 additional weeks of modafinil. Inclusion criteria included written approval from the primary care physician, clinically significant fatigue, current use of anti-retroviral medications, and the absence of treatable medical conditions known to cause fatigue. Exclusion criteria included untreated major depression and current substance abuse. Major outcome measures were the Fatigue Severity Scale, Chalder Fatigue Scale, Hamilton Rating Scale for Depression, Beck Depression Inventory, and neuropsychological tests assessing verbal memory, speed of processing, and executive function. Immunologic and virologic measures were performed at baseline and week 4 to assess safety of treatment. All 30 patients who enrolled completed 4 weeks of treatment; 24 (80%) were rated as responders. Responders showed statistically significant improvement on all measures of fatigue, depressive symptoms, and executive function, while nonresponders did not. Mean values of CD4 cell count and HIV RNA viral load did not change. The most common side effect was headache, followed by irritability and feeling "hyper." This pilot study shows encouraging results for modafinil in alleviation of fatigue in HIV+ patients. In addition, depressive symptoms were substantially reduced. Improvements on measures of verbal memory and executive function were significant, but in the absence of a placebo control, the magnitude of effect due to practice cannot be determined.

Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome.

PubMed

Buskila, D

2001-03-01

The prevalence of chronic widespread pain in the general population in Israel was comparable with reports from the USA, UK, and Canada. Comorbidity with fibromyalgia (FM) resulted in somatic hyperalgesia in patients with irritable bowel syndrome. One sixth of the subjects with chronic widespread pain in the general population were also found to have a mental disorder. Mechanisms involved in referred pain, temporal summation, muscle hyperalgesia, and muscle pain at rest were attenuated by the N-methyl-D-aspartate (NMDA) antagonist, ketamine, in FM patients. Delayed corticotropin release, after interleukin-6 administration, in FM was shown to be consistent with a defect in hypothalamic corticotropin-releasing hormone neural function. The basal autonomic state of FM patients was characterized by increased sympathetic and decreased parasympathetic systems tones. The severity of functional impairment as assessed by the Medical Outcome Survey Short Form (SF-36) discriminated between patients with widespread pain alone and FM patients. Chronic fatigue syndrome (CFS) occurred in about 0.42% of a random community-based sample of 28,673 adults in Chicago, Illinois. A significant clinical overlap between CFS and FM was reported. Cytokine dysregulation was not found to be a singular or dominant factor in the pathogenesis of CFS. A favorable outcome of CFS in children was reported; two thirds recovered and resumed normal activities. No major therapeutic trials in FM and CFS were reported over the past year.

A framework for fibromyalgia management for primary care providers.

PubMed

Arnold, Lesley M; Clauw, Daniel J; Dunegan, L Jean; Turk, Dennis C

2012-05-01

Fibromyalgia is a chronic widespread pain disorder commonly associated with comorbid symptoms, including fatigue and nonrestorative sleep. As in the management of other chronic medical disorders, the approach for fibromyalgia management follows core principles of comprehensive assessment, education, goal setting, multimodal treatment including pharmacological (eg, pregabalin, duloxetine, milnacipran) and nonpharmacological therapies (eg, physical activity, behavioral therapy, sleep hygiene, education), and regular education and monitoring of treatment response and progress. Based on these core management principles, this review presents a framework for primary care providers through which they can develop a patient-centered treatment program for patients with fibromyalgia. This proactive and systematic treatment approach encourages ongoing education and patient self-management and is designed for use in the primary care setting. Copyright © 2012 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Best Practices for Fatigue Risk Management in Non-Traditional Shiftwork

NASA Technical Reports Server (NTRS)

Flynn-Evans, Erin E.

2016-01-01

Fatigue risk management programs provide effective tools to mitigate fatigue among shift workers. Although such programs are effective for typical shiftwork scenarios, where individuals of equal skill level can be divided into shifts to cover 24 hour operations, traditional programs are not sufficient for managing sleep loss among individuals with unique skill sets, in occupations where non-traditional schedules are required. Such operations are prevalent at NASA and in other high stress occupations, including among airline pilots, military personnel, and expeditioners. These types of operations require fatigue risk management programs tailored to the specific requirements of the mission. Without appropriately tailored fatigue risk management, such operations can lead to an elevated risk of operational failure, disintegration of teamwork, and increased risk of accidents and incidents. In order to design schedules for such operations, schedule planners must evaluate the impact of a given operation on circadian misalignment, acute sleep loss, chronic sleep loss and sleep inertia. In addition, individual-level factors such as morningness-eveningness preference and sleep disorders should be considered. After the impact of each of these factors has been identified, scheduling teams can design schedules that meet operational requirements, while also minimizing fatigue.

Research on a Lamb Wave and Particle Filter-Based On-Line Crack Propagation Prognosis Method.

PubMed

Chen, Jian; Yuan, Shenfang; Qiu, Lei; Cai, Jian; Yang, Weibo

2016-03-03

Prognostics and health management techniques have drawn widespread attention due to their ability to facilitate maintenance activities based on need. On-line prognosis of fatigue crack propagation can offer information for optimizing operation and maintenance strategies in real-time. This paper proposes a Lamb wave-particle filter (LW-PF)-based method for on-line prognosis of fatigue crack propagation which takes advantages of the possibility of on-line monitoring to evaluate the actual crack length and uses a particle filter to deal with the crack evolution and monitoring uncertainties. The piezoelectric transducers (PZTs)-based active Lamb wave method is adopted for on-line crack monitoring. The state space model relating to crack propagation is established by the data-driven and finite element methods. Fatigue experiments performed on hole-edge crack specimens have validated the advantages of the proposed method.

Feeling Well Rested and Wide Awake When it Counts

NASA Technical Reports Server (NTRS)

2006-01-01

Responding to a congressional concern about aviation safety, NASA's Ames Research Center created the Ames Fatigue/Jet Lag Program in 1980 to examine the extent to which fatigue, sleep loss, and circadian disruption affect pilot performance. The program s primary research was conducted in field settings, as well as in a variety of aviation, controlled laboratory, and full-mission flight-simulation environments, to study fatigue factors and circadian disruption in short-haul, long-haul, military, cargo, and helicopter operations. In 1990, NASA changed the program s name to the Fatigue Countermeasures Group, to provide a greater emphasis on the development and evaluation of countermeasures that would mitigate the adverse effects of fatigue and maximize flight crew performance and alertness. The research conducted by this group at Ames included field studies of cockpit rest, quantity and quality of onboard sleep, and performance changes associated with long-haul flights.

Improvement of fatigue in multiple sclerosis by physical exercise is associated to modulation of systemic interferon response.

PubMed

Mulero, Patricia; Almansa, Raquel; Neri, María José; Bermejo-Martin, Jesús Francisco; Archanco, Miguel; Arenillas, Juan Francisco; Téllez, Nieves

2015-03-15

Mechanisms underlying multiple sclerosis (MS) fatigue and the causes of the beneficial effect of exercise on this symptom are not clarified. Our aim was to evaluate gene expression profiles in MS patients who improved their fatigue status after an exercise program and to compare them with healthy controls (HC). Gene expression in whole blood was profiled at baseline in 7 HC and also in 7 fatigued-MS patients. Patients underwent an exercise program for 6 months, and their fatigue status and gene expression profiles were again analyzed. MS patients showed a significant activation of genes participating in the systemic interferon response in comparison with HC that disappeared at the end of the program. Our results provide a biological basis for the observed benefit of exercise in MS. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of a compassion fatigue resiliency program for oncology nurses.

PubMed

Potter, Patricia; Deshields, Teresa; Berger, Julia Allen; Clarke, Marty; Olsen, Sarah; Chen, Ling

2013-03-01

To evaluate a resiliency program designed to educate oncology nurses about compassion fatigue. Descriptive pilot study. A National Cancer Institute-designated comprehensive cancer center in the midwestern United States. 13 oncology nurses employed in an outpatient infusion center. Nurses attended a five-week program involving five 90-minute sessions on compassion fatigue resiliency. A pre- and post-test design, using repeated measures, was conducted over six months. Scores on the Professional Quality of Life (ProQOL) IV, Maslach Burnout Inventory-Human Services Survey, Impact of Event Scale-Revised (IES-R), and the Nursing Job Satisfaction Scale. Long-term benefits were realized from the program. Secondary traumatization scores on the ProQOL IV declined immediately after the program, remained down at three months, and then dropped again at six months, with a statistically significant mean difference compared with baseline. The average IES-R total scores improved significantly overall and for each of the three postintervention time points. Participants evaluated the program positively with respect to their ability to apply and benefit from resiliency techniques. This is the first reported study to show benefits gained from a compassion fatigue intervention program. Participants received useful strategies for managing stress at work and home. Compassion fatigue is a prevalent condition among healthcare providers. Development of resiliency to compassion fatigue may improve decision making, clarity of communication, and patient and nurse satisfaction. Self-regulation offers an approach to reduce stress during a perceived threat. Working by intention reduces reactivity in the workplace and makes communication more intentional and, therefore, effective.

Characterization of fatigue crack growth behavior in LENS fabricated Ti-6Al-4V using high-energy synchrotron x-ray microtomography

DOE PAGES

Sandgren, Hayley R.; Zhai, Yuwei; Lados, Diana A.; ...

2016-09-28

Laser Engineered Net Shaping (LENS) is an additive manufacturing technique that belongs to the ASTM standardized directed energy deposition category. To date, very limited work has been conducted towards understanding the fatigue crack growth behavior of LENS fabricated materials, which hinders the widespread adoption of this technology for high-integrity structural applications. In this study, the propagation of a 20 μm initial crack in LENS fabricated Ti-6Al-4V was captured in-situ, using high-energy synchrotron x-ray microtomography. Fatigue crack growth (FCG) data were then determined from 2D and 3D tomography reconstructions, as well as from fracture surface striation measurements using SEM. The generatedmore » data were compared to those obtained from conventional FCG tests that used compliance and direct current potential drop (DCPD) techniques to measure long and small crack growth. In conclusion, the observed agreement demonstrates that x-ray microtomography and fractographic analysis using SEM can be successfully combined to study the propagation behavior of fatigue cracks.« less

Characterization of fatigue crack growth behavior in LENS fabricated Ti-6Al-4V using high-energy synchrotron x-ray microtomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandgren, Hayley R.; Zhai, Yuwei; Lados, Diana A.

Laser Engineered Net Shaping (LENS) is an additive manufacturing technique that belongs to the ASTM standardized directed energy deposition category. To date, very limited work has been conducted towards understanding the fatigue crack growth behavior of LENS fabricated materials, which hinders the widespread adoption of this technology for high-integrity structural applications. In this study, the propagation of a 20 μm initial crack in LENS fabricated Ti-6Al-4V was captured in-situ, using high-energy synchrotron x-ray microtomography. Fatigue crack growth (FCG) data were then determined from 2D and 3D tomography reconstructions, as well as from fracture surface striation measurements using SEM. The generatedmore » data were compared to those obtained from conventional FCG tests that used compliance and direct current potential drop (DCPD) techniques to measure long and small crack growth. In conclusion, the observed agreement demonstrates that x-ray microtomography and fractographic analysis using SEM can be successfully combined to study the propagation behavior of fatigue cracks.« less

Perceived stress and fatigue among students in a doctor of chiropractic training program.

PubMed

Kizhakkeveettil, Anupama; Vosko, Andrew M; Brash, Marissa; Ph, Dr; Philips, Michael A

2017-03-01

High levels of stress and fatigue are associated with decreased academic success, well-being, and quality of life. The objective of this research was to quantify levels of perceived stress and fatigue among chiropractic students to identify sources of and student coping mechanisms for perceived stress and fatigue and to identify the relationship between students' perceived stress and fatigue. A survey comprised of the Perceived Stress Scale, the Undergraduate Sources of Stress Survey, and the Piper Fatigue Scale was administered to chiropractic students in their 2nd, 5th, and 8th trimesters of doctoral study. Data were analyzed by descriptive statistics, 1-way analysis of variance, and linear correlation tests. Students reported having moderate to high levels of stress and fatigue, with higher levels of stress and fatigue seen in women than in men. A nonsignificant difference among stress scores and a significant difference among fatigue scores were observed based on program term. Levels of stress predicted levels of fatigue, and stress was strongly correlated with psychological health, relationships with family members, mood, and need for learning accommodations. Fatigue was strongly correlated with psychological health, academic demands, and conflicts between studies and other activities. There are differences in the reporting of perceived stress and fatigue levels in this chiropractic student population based on gender. The correlation between fatigue and stress also suggests that measures that may alleviate one may likely affect the other.

Exercise training in adults with Pompe disease: the effects on pain, fatigue, and functioning.

PubMed

Favejee, Marein M; van den Berg, Linda E M; Kruijshaar, Michelle E; Wens, Stephan C A; Praet, Stephan F E; Pim Pijnappel, W W M; van Doorn, Pieter A; Bussmann, Johannes B J; van der Ploeg, Ans T

2015-05-01

To assess if a 12-week exercise intervention to improve aerobic fitness, muscle strength, and core stability also had an impact on fatigue, pain, activity, and participation in adults with Pompe disease, an inherited neuromuscular disorder. Open-label trial. Change was assessed by the chi-square test and Wilcoxon signed-rank test. Physiotherapy practices. Mildly affected adult patients with Pompe disease who were not dependent on ventilators and/or walking devices and were receiving enzyme replacement therapy. Patients participated in a 12-week exercise program, which included 36 sessions of standardized aerobic, resistance, and core stability exercises. Before and after the training program we evaluated fatigue (Fatigue Severity Scale), pain (yes/no), motor function (Quantitative Muscle Function Test, Rasch-built Pompe-specific Activity Scale), amount of physical activity (activity monitor), and health status (Medical Outcomes Study 36-Item Short-Form Health Survey). Of the 25 patients enrolled, 23 completed the program. At the end of the program, levels of fatigue (median, 5.33 to 4.78, P=.01) and pain (56.5% to 21.7%, P=.04) improved. The quality of motor function and the amount of physical activity patients engaged in did not change. Changes in pain and fatigue were not related to improvements in aerobic fitness or muscle strength. This study in mildly affected adult patients with Pompe disease suggests that a combined training program aiming to increase aerobic fitness, muscle strength, and core stability also leads to improvements in fatigue and pain. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

"A Group of Me's": Adult Learning through Group Process: The Experiences of Participants in a Teleconference Delivered Multiple Sclerosis Fatigue Management Program

ERIC Educational Resources Information Center

Preissner, Katharine L.

2013-01-01

Multiple sclerosis (MS) is a chronic, progressive neurological disorder that affects approximately 2.1 million people worldwide. Fatigue is one of the most common and most disabling symptoms of MS. One well-established approach to address fatigue is fatigue management education provided by an occupational therapist. Fatigue management education is…

Shift work and employee fatigue: implications for occupational health nursing.

PubMed

Yumang-Ross, Doreen J; Burns, Candace

2014-06-01

Long work hours and irregular shifts are part of the nation's 24-hour society and contribute to employee fatigue. Factors affecting employee fatigue are circadian rhythm, sleep quality and quantity, individual health, the environment, and work tasks. Employee fatigue contributes to accidents and injuries, and affects occupational performance, safety, and health. These findings should be used by occupational health nurses to address fatigue management and develop comprehensive fatigue management programs. Copyright 2014, SLACK Incorporated.

10 CFR 26.211 - Fatigue assessments.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Fatigue assessments. 26.211 Section 26.211 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Managing Fatigue § 26.211 Fatigue assessments. (a) Licensees... addition to any other test or determination of fitness that may be required under §§ 26.31(c) and 26.77, a...

10 CFR 26.211 - Fatigue assessments.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Fatigue assessments. 26.211 Section 26.211 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Managing Fatigue § 26.211 Fatigue assessments. (a) Licensees... addition to any other test or determination of fitness that may be required under §§ 26.31(c) and 26.77, a...

Fatigue methodology III; Proceedings of the AHS National Technical Specialists' Meeting on Advanced Rotorcraft Structures, Scottsdale, AZ, Oct. 3-5, 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1989-01-01

Papers on rotorcraft and fatigue methodology are presented, covering topics such as reliability design for rotorcraft, a comparison between theory and fatigue test data on stress concentration factors, the retirement lives of rolling element bearings, hydrogen embrittlement risk analysis for high hardness steel parts, and rotating system load monitoring with minimum fixed system instrumentation. Additional topics include usage data collection to improve structural integrity of operational helicopters, usage monitory of military helicopters, improvements to the fatigue substantiation of the H-60 composite tail rotor blade, helicopter surviellance programs, and potential application of automotive fatigue technology in rotorcraft design. Also, consideration ismore » given to fatigue evaluation of C/MH-53 E main rotor damper threaded joints, SH-2F airframe fatigue test program, a ply termination concept for improving fracture and fatigue strength of composite laminates, the analysis and testing of composite panels subject to muzzle blast effects, the certification plan for an all-composite main rotor flexbeam, and the effects of stacking sequence on the flexural strength of composite beams.« less

Computer program to assess impact of fatigue and fracture criteria on weight and cost of transport aircraft

NASA Technical Reports Server (NTRS)

Tanner, C. J.; Kruse, G. S.; Oman, B. H.

1975-01-01

A preliminary design analysis tool for rapidly performing trade-off studies involving fatigue, fracture, static strength, weight, and cost is presented. Analysis subprograms were developed for fatigue life, crack growth life, and residual strength; and linked to a structural synthesis module which in turn was integrated into a computer program. The part definition module of a cost and weight analysis program was expanded to be compatible with the upgraded structural synthesis capability. The resultant vehicle design and evaluation program is named VDEP-2. It is an accurate and useful tool for estimating purposes at the preliminary design stage of airframe development. A sample case along with an explanation of program applications and input preparation is presented.

Sonic fatigue testing of an advanced composite aileron

NASA Technical Reports Server (NTRS)

Soovere, J.

1982-01-01

The sonic fatigue test program to verify the design of the composite inboard aileron for the L-1011 airplane is described. The composite aileron is fabricated from graphite/epoxy minisandwich covers which are attached to graphite/epoxy front spar and ribs, and to an aluminum rear spar with fasteners. The program covers the development of random fatigue data by means of coupon testing and modal studies on a representative section of the composite aileron, culminating in the accelerated sonic fatigue proof test. The composite aileron sustained nonlinear panel vibration during the proof test without failure. Viscous damping coefficients as low as 0.4% were measured on the panels. The effects of moisture conditioning and elevated temperature on the random fatigue life of both undamaged and impact damaged coupons were investigated. The combination of impact damage, moisture, and a 180 F temperature could reduce the random fatigue life by 50%.

Improved High-Cycle Fatigue (HCF) Life Prediction

DTIC Science & Technology

2001-01-01

fatigue in 2024 - T351 aluminum alloy ’, Wear 221, 24-36. Appendix 6C CHARACTERIZATION OF FRETTING FATIGUE INITIATED CRACKS P.J. Golden A.F...0.8. To evaluate the effects of surface residual stresses on notch fatigue life , shot peened specimens were tested at R = -1.0 and 0.1. Data in...Behavior - Response • The undamaged fatigue test program demonstrates the sensitivity of surface effects (for different

Probabilistic analysis for fatigue strength degradation of materials

NASA Technical Reports Server (NTRS)

Royce, Lola

1989-01-01

This report presents the results of the first year of a research program conducted for NASA-LeRC by the University of Texas at San Antonio. The research included development of methodology that provides a probabilistic treatment of lifetime prediction of structural components of aerospace propulsion systems subjected to fatigue. Material strength degradation models, based on primitive variables, include both a fatigue strength reduction model and a fatigue crack growth model. Linear elastic fracture mechanics is utilized in the latter model. Probabilistic analysis is based on simulation, and both maximum entropy and maximum penalized likelihood methods are used for the generation of probability density functions. The resulting constitutive relationships are included in several computer programs, RANDOM2, RANDOM3, and RANDOM4. These programs determine the random lifetime of an engine component, in mechanical load cycles, to reach a critical fatigue strength or crack size. The material considered was a cast nickel base superalloy, one typical of those used in the Space Shuttle Main Engine.

Effectiveness and cost-effectiveness of a self-management group program to improve social participation in patients with neuromuscular disease and chronic fatigue: protocol of the Energetic study.

PubMed

Veenhuizen, Yvonne; Cup, Edith H C; Groothuis, Jan T; Hendriks, Jan C M; Adang, Eddy M M; van Engelen, Baziel G M; Geurts, Alexander C H

2015-04-19

Chronic fatigue is present in more than 60% of the patients with a neuromuscular disease and can be their most disabling symptom. In combination with other impairments, fatigue often results in low levels of physical activity and decreased social participation, leading to high societal costs. 'Energetic' is a self-management group program aimed at improving social participation, physical endurance and alleviating fatigue in these patients. The primary aim of this study is to evaluate the effectiveness and cost-effectiveness of the Energetic program. A multicentered, assessor-blinded, two-armed randomized controlled trial is conducted with evaluations at inclusion and four, seven and fifteen months later. The study includes patients with a neuromuscular disease and chronic fatigue and, when present, their caregivers. The participants are randomized (ratio 1:1) to either an intervention group, receiving the Energetic program, or a control group, receiving usual care (i.e., no specific intervention). The Energetic program covers four months and includes four modules: 1) individually tailored aerobic exercise training; 2) education about aerobic exercise; 3) self-management training in applying energy conservation strategies; and 4) implementation and relapse prevention in daily life. Two months after cessation of the program a booster session is provided. The primary outcome is the perceived performance score of the Canadian Occupational Performance Measure (COPM). Secondary outcomes include the COPM-satisfaction score, and measures of fatigue, physical endurance, activity engagement, mood, and self-efficacy. Caregiver burden is also evaluated as a secondary outcome. Health-related quality of life and medical and societal costs are assessed to estimate cost-effectiveness of the program. The Energetic study is the first randomized controlled trial to evaluate the effectiveness and cost-effectiveness of a combined physical and self-management group training program for improving social participation, physical endurance and alleviating fatigue in patients with neuromuscular diseases. It will generate new insights in (cost-)effective rehabilitation strategies for these incurable conditions. Clinicaltrials.gov NCT02208687 .

The Characteristics of Fatigue Damage in the Fuselage Riveted Lap Splice Joint

NASA Technical Reports Server (NTRS)

Piascik, Robert S.; Willard, Scott A.

1997-01-01

An extensive data base has been developed to form the physical basis for new analytical methodology to predict the onset of widespread fatigue damage in the fuselage lap splice joint. The results of detailed destructive examinations have been cataloged to describe the physical nature of MSD in the lap splice joint. ne catalog includes a detailed description, e.g., crack initiation, growth rates, size, location, and fracture morphology, of fatigue damage in the fuselage lap splice joint structure. Detailed examinations were conducted on a lap splice joint panel removed from a full scale fuselage test article after completing a 60,000 cycle pressure test. The panel contained a four bay region that exhibited visible outer skin cracks and regions of crack link-up along the upper rivet row. Destructive examinations revealed undetected fatigue damage in the outer skin, inner skin, and tear strap regions. Outer skin fatigue cracks were found to initiate by fretting damage along the faying surface. The cracks grew along the faying surface to a length equivalent to two to three skin thicknesses before penetrating the outboard surface of the outer skin. Analysis of fracture surface marker bands produced during full scale testing revealed that all upper rivet row fatigue cracks contained in a dim bay region grow at similar rates; this important result suggests that fracture mechanics based methods can be used to predict the growth of outer skin fatigue cracks in lap splice structure. Results are presented showing the affects of MSD and out-of-plane pressure loads on outer skin crack link-up.

Material fatigue data obtained by card-programmed hydraulic loading system

NASA Technical Reports Server (NTRS)

Davis, W. T.

1967-01-01

Fatigue tests using load distributions from actual loading histories encountered in flight are programmed on punched electronic accounting machine cards. With this hydraulic loading system, airframe designers can apply up to 55 load levels to a test specimen.

Compassion Fatigue in the Military Caregiver

DTIC Science & Technology

2009-03-01

Compassion Fatigue/ Burnout Syndrome Figley, C (1995; 97)19 Sprang, Clark, and Whitt-Woosley in their article, “Compassion Fatigue, Compassion...alternative or additional programs, process or intervention to address compassion fatigue, burnout , stress disorder or other debilitating post-traumatic...effects. 15. SUBJECT TERMS Caregiver, Care Provider, Secondary Traumatic Stress, Combat Trauma, Shared Trauma, Posttraumatic Stress Disorder, Burnout 16

30 CFR 250.908 - What are the minimum structural fatigue design requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false What are the minimum structural fatigue design... Platform Approval Program § 250.908 What are the minimum structural fatigue design requirements? (a) API RP... (incorporated by reference as specified in 30 CFR 250.198), requires that the design fatigue life of each joint...

Microstructure-based approach for predicting crack initiation and early growth in metals.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, James V.; Emery, John M.; Brewer, Luke N.

2009-09-01

Fatigue cracking in metals has been and is an area of great importance to the science and technology of structural materials for quite some time. The earliest stages of fatigue crack nucleation and growth are dominated by the microstructure and yet few models are able to predict the fatigue behavior during these stages because of a lack of microstructural physics in the models. This program has developed several new simulation tools to increase the microstructural physics available for fatigue prediction. In addition, this program has extended and developed microscale experimental methods to allow the validation of new microstructural models formore » deformation in metals. We have applied these developments to fatigue experiments in metals where the microstructure has been intentionally varied.« less

Effects of an 8-Week Outdoor Brisk Walking Program on Fatigue in Hi-Tech Industry Employees: A Randomized Control Trial.

PubMed

Wu, Li-Ling; Wang, Kuo-Ming; Liao, Po-I; Kao, Yu-Hsiu; Huang, Yi-Ching

2015-10-01

Over 73% of hi-tech industry employees in Taiwan lack regular exercise. They are exposed to a highly variable and stressful work environment for extended periods of time, and may subsequently experience depression, detrimental to workers' physiological and mental health. In this cross-sectional survey, the authors explored the effect of an 8-week brisk walking program on the fatigue of employees in the hi-tech industry. The participants, from a hi-tech company in northern Taiwan, were randomly assigned to an experimental group (EG; 41 subjects, Mage = 33.34 ± 6.40) or control group (CG; 45 subjects, Mage = 29.40 ± 3.60). Following the 8-week brisk walking program, the EG showed significantly lower scores for subjective fatigue, working motivation, attention, and overall fatigue. The authors confirmed that the 8-week outdoor brisk walking program significantly improved the level of fatigue among employees of the hi-tech industry. The finding serves as an important reference for health authorities in Taiwan and provides awareness of workplace health promotion in the hi-tech industry. © 2015 The Author(s).

The role of fretting corrosion and fretting fatigue in aircraft rivet hole cracking

NASA Technical Reports Server (NTRS)

Elliott, Charles B., III; Moesser, Mark; Hoeppner, David W.

1994-01-01

Personnel in the Quality and Integrity Design Engineering Center (QIDEC) at the University of Utah are working under a two year grant from the FAA to better understand the role of fretting corrosion and fretting fatigue in aircraft rivet hole cracking. The current program follows a one year grant program which was completed in 1993. This paper provides a status report on the results of these grant programs. Recent effort has been focused on developing basic fretting fatigue models which consider variation in the coefficient of friction with time and location within the fretting interface. This is a very important characteristic of the QIDEC model because coefficient of friction varies significantly during the fretting fatigue process. Copies of QIDEC documents discussed in this paper can be obtained by contacting the authors.

United States Air Force Summer Faculty Research Program for 1990. Program Management Report

DTIC Science & Technology

1991-06-05

propagation characteristics were extensively studied using pencil lead breaks in a center notch. For the fatigue studies center crack samples of 2024 - T351 ... aluminum specimens during fatigue cycling. The experimental procedure involved excitation of Rayleigh waves on the surface of each specimen and...Research Program (SFRP) provides opportunities for research in the physical sciences, engineering, and life sciences. The program has been effective

Analysis of methods for determining high cycle fatigue strength of a material with investigation of titanium-aluminum-vanadium gigacycle fatigue behavior

NASA Astrophysics Data System (ADS)

Pollak, Randall D.

Today, aerospace engineers still grapple with the qualitative and quantitative understanding of fatigue behavior in the design and testing of turbine-driven jet engines. The Department of Defense has taken a very active role in addressing this problem with the formation of the National High Cycle Fatigue Science & Technology Program in 1994. The primary goal of this program is to further the understanding of high cycle fatigue (HCF) behavior and develop methods in order to mitigate the negative impact of HCF on aerospace operations. This research supports this program by addressing the fatigue strength testing guidance currently provided by the DoD to engine manufacturers, with the primary goal to investigate current methods and recommend a test strategy to characterize the fatigue strength of a material at a specified number of cycles, such as the 109 design goal specified by MIL-HDBK-1783B, or range of cycles. The research utilized the benefits of numerical simulation to initially investigate the staircase method for use in fatigue strength testing. The staircase method is a commonly used fatigue strength test, but its ability to characterize fatigue strength variability is extremely suspect. A modified staircase approach was developed and shown to significantly reduce bias and scatter in estimates for fatigue strength variance. Experimental validation of this proposed test strategy was accomplished using a dual-phase Ti-6Al-4V alloy. The HCF behavior of a second material with a very different microstructure (beta annealed Ti-6Al-4V) was also investigated. The random fatigue limit (RFL) model, a recently developed analysis tool, was investigated to characterize stress-life behavior but found to have difficulty representing fatigue life curves with sharp transitions. Two alternative models (bilinear and hyperbolic) were developed based on maximum likelihood methods to better characterize the Ti-6Al-4V fatigue life behavior. These models provided a good fit to the experimental data for the dual-phase Ti-6Al-4V and were applied to the beta annealed variant in order to estimate stress-life behavior using a small-sample approach. Based on this research, designers should be better able to make reliable estimates of fatigue strength parameters using small-sample testing.

Effects of blurring and vertical misalignment on visual fatigue of stereoscopic displays

NASA Astrophysics Data System (ADS)

Baek, Sangwook; Lee, Chulhee

2015-03-01

In this paper, we investigate two error issues in stereo images, which may produce visual fatigue. When two cameras are used to produce 3D video sequences, vertical misalignment can be a problem. Although this problem may not occur in professionally produced 3D programs, it is still a major issue in many low-cost 3D programs. Recently, efforts have been made to produce 3D video programs using smart phones or tablets, which may present the vertical alignment problem. Also, in 2D-3D conversion techniques, the simulated frame may have blur effects, which can also introduce visual fatigue in 3D programs. In this paper, to investigate the relationship between these two errors (vertical misalignment and blurring in one image), we performed a subjective test using simulated 3D video sequences that include stereo video sequences with various vertical misalignments and blurring in a stereo image. We present some analyses along with objective models to predict the degree of visual fatigue from vertical misalignment and blurring.

Common questions about the diagnosis and management of fibromyalgia.

PubMed

Kodner, Charles

2015-04-01

Fibromyalgia has a distinct pathophysiology involving central amplification of peripheral sensory signals. Core symptoms are chronic widespread pain, fatigue, and sleep disturbance. Most patients with fibromyalgia have muscle pain and tenderness, forgetfulness or problems concentrating, and significant functional limitations. Fibromyalgia is diagnosed using an updated set of clinical criteria that no longer depend on tender point examination; laboratory testing may rule out other disorders that commonly present with fatigue, such as anemia and thyroid disease. Patients with fibromyalgia should be evaluated for comorbid functional pain syndromes and mood disorders. Management of fibromyalgia should include patient education, symptom relief, and regular aerobic physical activity. Serotoninnorepinephrine reuptake inhibitors, tricyclic antidepressants, antiepileptics, and muscle relaxants have the strongest evidence of benefit for improving pain, fatigue, sleep symptoms, and quality of life. Multiple complementary and alternative medicine therapies have been used but have limited evidence of effectiveness. Opioids should be used to relieve pain in carefully selected patients only if alternative therapies are ineffective.

A unified technology plan for fatigue and fracture design

NASA Technical Reports Server (NTRS)

Hardrath, H. F.

1973-01-01

An integrated research program is proposed that seeks to improve the technology of designing against fatigue and fracture and to develop a computerized capability for assessing the adequacy of a given design. Both fatigue life prediction and damage tolerance considerations are incorporated. The research for each of these considerations is organized to account for material behavior, the effect of structural configurations, the cumulative effects of the operating loadings, and for the effects of environment - temperature and corrosion. The goal is to achieve a viable fatigue and fracture design procedure for any practical problem. The overall program is outlined, assessments are made of the state of the art, subgoals are proposed, and means for achieving them are suggested.

High Speed Research Program Structural Acoustics Multi-Year Summary Report

NASA Technical Reports Server (NTRS)

Beier, Theodor H.; Bhat, Waman V.; Rizzi, Stephen A.; Silcox, Richard J.; Simpson, Myles A.

2005-01-01

This report summarizes the work conducted by the Structural Acoustics Integrated Technology Development (ITD) Team under NASA's High Speed Research (HSR) Phase II program from 1993 to 1999. It is intended to serve as a reference for future researchers by documenting the results of the interior noise and sonic fatigue technology development activities conducted during this period. For interior noise, these activities included excitation modeling, structural acoustic response modeling, development of passive treatments and active controls, and prediction of interior noise. For sonic fatigue, these activities included loads prediction, materials characterization, sonic fatigue code development, development of response reduction techniques, and generation of sonic fatigue design requirements. Also included are lessons learned and recommendations for future work.

Methods for structural design at elevated temperatures

NASA Technical Reports Server (NTRS)

Ellison, A. M.; Jones, W. E., Jr.; Leimbach, K. R.

1973-01-01

A procedure which can be used to design elevated temperature structures is discussed. The desired goal is to have the same confidence in the structural integrity at elevated temperature as the factor of safety gives on mechanical loads at room temperature. Methods of design and analysis for creep, creep rupture, and creep buckling are presented. Example problems are included to illustrate the analytical methods. Creep data for some common structural materials are presented. Appendix B is description, user's manual, and listing for the creep analysis program. The program predicts time to a given creep or to creep rupture for a material subjected to a specified stress-temperature-time spectrum. Fatigue at elevated temperature is discussed. Methods of analysis for high stress-low cycle fatigue, fatigue below the creep range, and fatigue in the creep range are included. The interaction of thermal fatigue and mechanical loads is considered, and a detailed approach to fatigue analysis is given for structures operating below the creep range.

Differential effects of bifrontal and occipital nerve stimulation on pain and fatigue using transcranial direct current stimulation in fibromyalgia patients.

PubMed

To, Wing Ting; James, Evan; Ost, Jan; Hart, John; De Ridder, Dirk; Vanneste, Sven

2017-07-01

Fibromyalgia is a disorder characterized by widespread musculoskeletal pain frequently accompanied by other symptoms such as fatigue. Moderate improvement from pharmacological and non-pharmacological treatments have proposed non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) to the occipital nerve (more specifically the C2 area) or to the dorsolateral prefrontal cortex (DLPFC) as potential treatments. We aimed to explore the effectiveness of repeated sessions of tDCS (eight sessions) targeting the C2 area and DLPFC in reducing fibromyalgia symptoms, more specifically pain and fatigue. Forty-two fibromyalgia patients received either C2 tDCS, DLPFC tDCS or sham procedure (15 C2 tDCS-11 DLPFC tDCS-16 sham). All groups were treated with eight sessions (two times a week for 4 weeks). Our results show that repeated sessions of C2 tDCS significantly improved pain, but not fatigue, in fibromyalgia patients, whereas repeated sessions of DLPFC tDCS significantly improved pain as well as fatigue. This study shows that eight sessions of tDCS targeting the DLPFC have a more general relief in fibromyalgia patients than when targeting the C2 area, suggesting that stimulating different targets with eight sessions of tDCS can lead to benefits on different symptom dimensions of fibromyalgia.

Fatigue Test Design: Scenarios for Biaxial Fatigue Testing of a 60-Meter Wind Turbine Blade

DOE Office of Scientific and Technical Information (OSTI.GOV)

Post, Nathan

Current practice in commercial certification of wind turbine blades is to perform separate flap and lead-lag fatigue tests. The National Renewable Energy Laboratory has been researching and evaluating biaxial fatigue testing techniques and demonstrating various options, typically on smaller-scale test articles at the National Wind Technology Center. This report evaluates some of these biaxial fatigue options in the context of application to a multimegawatt blade certification test program at the Wind Technology Testing Center in Charlestown, Massachusetts.

Multidimensional daily diary of fatigue-fibromyalgia-17 items (MDF-fibro-17). part 1: development and content validity.

PubMed

Morris, S; Li, Y; Smith, J A M; Dube', S; Burbridge, C; Symonds, T

2017-05-16

Fibromyalgia (FM), a disorder characterized by chronic widespread pain and tenderness, affects greater than five million individuals in the United States alone. Patients experience multiple symptoms in addition to pain, and among them, fatigue is one of the most bothersome and disabling. There is a growing body of literature suggesting that fatigue is a multidimensional concept. Currently, to our knowledge, no multidimensional Patient Reported Outcome (PRO) measure of FM-related fatigue meets Food and Drug Administration (FDA) requirements to support a product label claim. Therefore, the objective of this research was to evaluate qualitative and quantitative data previously gathered to inform the development of a comprehensive, multidimensional, PRO measure to assess FM-related fatigue in FM clinical trials. Existing qualitative and quantitative data from three previously conducted studies in patients with FM were reviewed to inform the initial development of a multidimensional PRO measure of FM-related fatigue: 1) a concept elicitation study involving in-depth, open-ended interviews with patients with FM in the United States (US) (N = 20), Germany (N = 10), and France (N = 10); 2) a cognitive debriefing and pilot study of a preliminary pool of 23 items (N = 20 US patients with FM); and 3) a methodology study that explored initial psychometrics of the item pool (N = 145 US patients with FM). Five domains were identified that intend to capture the broad experience of FM-related fatigue reported in the qualitative research: the Global Fatigue Experience, Cognitive Fatigue, Physical Fatigue, Motivation, and Impact on Function. Seventeen of the original pool of 23 items were selected to best capture these five dimensions. These 17 items formed the basis of a newly developed multidimensional PRO measure to assess FM-related fatigue in clinical trials: the Multidimensional Daily Diary of Fatigue-Fibromyalgia-17 (MDF-Fibro-17). Qualitative analysis, and preliminary quantitative item level data, confirmed that FM-related fatigue is multidimensional and provided strong support for the content validity of the MDF-Fibro-17. The next stage was to quantitatively evaluate the measure to confirm the factor structure, psychometric properties, sensitivity to change, and meaningful change. This has been conducted and is being reported separately.

Impact of Moving From a Widespread to Multisite Pain Definition on Other Fibromyalgia Symptoms.

PubMed

Dean, Linda E; Arnold, Lesley; Crofford, Leslie; Bennett, Robert; Goldenberg, Don; Fitzcharles, Mary-Ann; Paiva, Eduardo S; Staud, Roland; Clauw, Dan; Sarzi-Puttini, Piercarlo; Jones, Gareth T; Ayorinde, Abimbola; Flüß, Elisa; Beasley, Marcus; Macfarlane, Gary J

2017-12-01

To investigate whether associations between pain and the additional symptoms associated with fibromyalgia are different in persons with chronic widespread pain (CWP) compared to multisite pain (MSP), with or without joint areas. Six studies were used: 1958 British birth cohort, Epidemiology of Functional Disorders, Kid Low Back Pain, Managing Unexplained Symptoms (Chronic Widespread Pain) in Primary Care: Involving Traditional and Accessible New Approaches, Study of Health and its Management, and Women's Health Study (WHEST; females). MSP was defined as the presence of pain in ≥8 body sites in adults (≥10 sites in children) indicated on 4-view body manikins, conducted first to include joints (positive joints) and second without (negative joints). The relationship between pain and fatigue, sleep disturbance, somatic symptoms, and mood impairment was assessed using logistic regression. Results are presented as odds ratios (ORs) with 95% confidence intervals (95% CIs). There were 34,818 participants across the study populations (adults age range 42-56 years, male 43-51% [excluding WHEST], and CWP prevalence 12-17%). Among those reporting MSP, the proportion reporting CWP ranged between 62% and 76%. Among those reporting the symptoms associated with fibromyalgia, there was an increased likelihood of reporting pain, the magnitude of which was similar regardless of the definition used. For example, within WHEST, reporting moderate/severe fatigue (Chalder fatigue scale 4-11) was associated with a >5-fold increase in likelihood of reporting pain (CWP OR 5.2 [95% CI 3.9-6.9], MSP-positive joints OR 6.5 [95% CI 5.0-8.6], and MSP-negative joints OR 6.5 [95% CI 4.7-9.0]). This large-scale study demonstrates that regardless of the pain definition used, the magnitude of association between pain and other associated symptoms of fibromyalgia is similar. This finding supports the continued collection of both when classifying fibromyalgia, but highlights the fact that pain may not require to follow the definition outlined within the 1990 American College of Rheumatology criteria. © 2017, American College of Rheumatology.

Alertness Management In Flight Operations: A NASA Education and Training Module

NASA Technical Reports Server (NTRS)

Rosekind, Mark R.; Lebacqz, Victor J.; Gander, Philippa H.; Co, Elizabeth L.; Weldon, Keri J.; Smith, Roy M.; Miller, Donna L.; Gregory, Kevin B.; Statler, Irving C. (Technical Monitor)

1994-01-01

Since 1980, the NASA Ames Fatigue Countermeasures Program has been conducting research on sleep, circadian rhythms, and fatigue in a variety of flight operations 1. An original goal of the program was to return the scientific and operational knowledge to the aviation industry. To meet this goal, the NASA Ames Fatigue Countermeasures Program has created an Education and Training Module entitled, "Strategies for Alertness Management in Flight Operations." The Module was designed to meet three objectives: 1) explain the current state of knowledge about the physiological mechanisms underlying fatigue, 2) demonstrate how this knowledge can be applied to improve flight crew sleep, performance, and alertness, and 3) offer countermeasure recommendations. The Module is composed of two components: 1) a 60-minute live presentation provided by a knowledgeable individual and 2) a NASA/FAA Technical Memorandum (TM) that contains the presentation materials and appendices with complementary information. The TM is provided to all individuals attending the live presentation. The Module content is divided into three parts: 1) basic information on sleep, sleepiness, circadian rhythms, fatigue, and how flight operations affect these physiological factors, 2) common misconceptions about sleep, sleepiness, and fatigue, and 3) alertness management strategies. The Module is intended for pilots, management personnel, schedulers, flight attendants, and the many other individuals involved in the aviation system.

Resistance training program for fatigue management in the workplace: exercise protocol in a cluster randomized controlled trial.

PubMed

Santos, Hélio Gustavo; Chiavegato, Luciana Dias; Valentim, Daniela Pereira; da Silva, Patricia Rodrigues; Padula, Rosimeire Simprini

2016-12-22

Fatigue is a multifactorial condition that leads to disease and loss in production, and it affects a large number of workers worldwide. This study aims to demonstrate a resistance exercise protocol that individuals will perform during the work schedule, and to evaluate the effectiveness of this exercises program for fatigue control. This is a cluster randomized controlled trial with two arms and is assessor blinded. A total of 352 workers of both sexes, aged 18-65 years, from a medium-sized dairy plant were enrolled in this study. Participants will be recruited from 13 production sectors according to the eligibility criteria and will be randomized by clusters to either the Progressive Resistance Exercise (PRE) intervention group or the Compensatory Workplace Exercise (CWE) comparative group. A resistance exercise program will be implemented for both groups. The groups will receive instructions on self-management, breaks, adjustments to workstations, and the benefits of physical exercise. The PRE group will perform resistance exercises with gradual loads in an exercise room, and the CWE group will perform exercise at their workstations using elastic bands. The exercise sessions will be held 3 times a week for 20 min. The primary outcome measures will be symptoms of physical and mental fatigue, and muscular fatigue based on a one-repetition maximum (1RM). The secondary outcome measures will be level of physical activity, musculoskeletal symptoms, physical condition, perceived exposure, and productivity. The workers will be assessed at baseline and after a 4-month program. A linear mixed model will be applied on an intention-to-treat basis. This intervention is expected to reduce symptoms of fatigue in the workers. The exercise program is indicating in the workplace, although there are few studies describing the effects of exercise on the control of fatigue in the workplace. Emphasis will be placed on adherence to the program, which may result in significant and clinically important reductions in fatigue. It is also expected that the findings of this study will contribute significantly to the decision-making capacity of professionals working in the field of occupational health. U.S. National Institutes of Health, ClinicalTrials.gov Identifier: NCT02172053 . Date registered 19 June 2014.

Advanced composite stabilizer for Boeing 737 aircraft

NASA Technical Reports Server (NTRS)

1978-01-01

Activities related to development of an advanced composites stabilizer for the Boeing 737 commercial transport are reported. Activities include discussion of criteria and objectives, design loads, the fatigue spectrum definition to be used for all spectrum fatigue testing, fatigue analysis, manufacturing producibility studies, the ancillary test program, quality assurance, and manufacturing development.

Occupational therapists' experience of workplace fatigue: Issues and action.

PubMed

Brown, Cary A; Schell, Jennifer; Pashniak, Lisa M

2017-01-01

Occupational therapists (OTs) work in all areas of health and wellbeing. The work is physically and psychologically demanding, but OTs are often not diligent about recognizing and attending to the workplace health and safety issue of fatigue in their own work settings. The purpose of this paper is to determine current issues and the evidence-base as presented in the literature so as to develop awareness and best practice interventions for fatigue reduction and management in occupational therapists' workplace. A comprehensive search strategy was carried out by the medical librarian on the study team and themes were extracted from the relevant literature by the study team. The literature revealed little research directly addressing occupational therapy workplace fatigue and we expanded our review of the evidence-base across all healthcare workers to identify publications of particular relevance to occupational therapists. This background paper is an important first step to raising awareness among OTs, guide key stakeholders regarding contributing factors to, and consequences of, OTs' workplace fatigue, and set research direction. Knowing which factors influencing workplace fatigue are shared across healthcare professionals and which are unique to OTs can also help organizations develop more tailored workplace fatigue risk reduction programs. This review concludes with a list of existing guidelines and tools for developing workplace fatigue risk assessment and management programs relevant to occupational therapists.

Automated predesign of aircraft

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.; Kruse, G. S.; Tanner, C. J.; Wilson, P. J.

1978-01-01

Program uses multistation structural-synthesis to size and design box-beam structures for transport aircraft. Program optimizes static strength and scales up to satisfy fatigue and fracture criteria. It has multimaterial capability and library of materials properties, including advanced composites. Program can be used to evaluate impact on weight of variables such as materials, types of construction, structural configurations, minimum gage limits, applied loads, fatigue lives, crack-growth lives, initial crack sizes, and residual strengths.

Prospective evaluation of a 12-week walking exercise program and its effect on fatigue in prostate cancer patients undergoing radical external beam radiotherapy.

PubMed

Truong, Pauline T; Gaul, Catherine A; McDonald, Rachel E; Petersen, Ross B; Jones, Stuart O; Alexander, Abraham S; Lim, Jan T W; Ludgate, Charles

2011-08-01

To evaluate tolerability and compliance to a walking exercise program and its effect on fatigue during and after radical external beam radiation therapy (EBRT) for prostate cancer. A total of 50 subjects with prostate cancer undergoing EBRT over 6 to 8 weeks were prospectively accrued to an exercise intervention group, matched for age and clinical characteristics to 30 subjects in a historical control group who underwent EBRT with no specific exercise intervention. Starting 1 week before EBRT, exercise participants performed moderate-intensity walking targeting 60% to 70% age-predicted maximum heart rate, at least 20 min/d, 3 d/wk over 12 weeks. The Brief Fatigue Inventory was administered at baseline, mid-EBRT (week 3-4), end-EBRT (week 6-8), and 6 months post-EBRT. Of 50, 42 (84%) of exercise participants completed the walking program. There were no cardiovascular complications, musculoskeletal injuries, or other adverse events. A total of 89% subjects reported "Good-Excellent" satisfaction during and up to 6 months post-EBRT. Fatigue in control subjects escalated from baseline to end-EBRT, remaining high at 6 months post-EBRT (P[r] = 0.03). In contrast, mean total fatigue scores in exercise subjects were stable from baseline up to 6 months post-EBRT (P = 0.52). Trends for higher fatigue interference with quality of life were observed in the control group as compared with the exercise group. Moderate-intensity walking exercise during radical EBRT is safe and feasible. The high convenience and satisfaction ratings, in conjunction with the observed fatigue trends, indicate that this activity has the potential to attenuate fatigue and improve quality of life for patients with localized prostate cancer undergoing curative therapy.

Load-Differential Features for Automated Detection of Fatigue Cracks Using Guided Waves (Preprint)

DTIC Science & Technology

2011-11-01

AFRL-RX-WP-TP-2011-4363 LOAD-DIFFERENTIAL FEATURES FOR AUTOMATED DETECTION OF FATIGUE CRACKS USING GUIDED WAVES (PREPRINT) Jennifer E...AUTOMATED DETECTION OF FATIGUE CRACKS USING GUIDED WAVES (PREPRINT) 5a. CONTRACT NUMBER FA8650-09-C-5206 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...tensile loads open fatigue cracks and thus enhance their detectability using ultrasonic methods. Here we introduce a class of load-differential methods

Fibromyalgia: a stress disorder? Piecing the biopsychosocial puzzle together.

PubMed

Van Houdenhove, Boudewijn; Egle, Ulrich T

2004-01-01

Fibromyalgia (FM) is a controversial syndrome, characterised by persistent widespread pain, abnormal pain sensitivity and additional symptoms such as fatigue and sleep disturbance. The syndrome largely overlaps with other functional somatic disorders, particularly chronic fatigue syndrome (CFS). Although the exact aetiology and pathogenesis of FM are still unknown, it has been suggested that stress may play a key role in the syndrome. This article first reviews the function of the stress response system, placing special emphasis on the relationships between adverse life experiences, stress regulation and pain-processing mechanisms, and summarising the evidence for a possible aetiopathogenetic role of stress in FM. Finally, an integrative biopsychosocial model that conceptualizes FM as a stress disorder is proposed, and the clinical and research implications of the model are discussed.

The effect of a virtual reality exercise program on physical fitness, body composition, and fatigue in hemodialysis patients.

PubMed

Cho, Hyeyoung; Sohng, Kyeong-Yae

2014-10-01

[Purpose] The aim of the present study was to investigate the effects of a virtual reality exercise program (VREP) on physical fitness, body composition, and fatigue in hemodialysis (HD) patients with end-stage renal failure. [Subjects and Methods] A nonequivalent control group pretest-posttest design was used. Forty-six HD patients were divided into exercise (n=23) and control groups (n=23); while waiting for their dialyses, the exercise group followed a VREP, and the control group received only their usual care. The VREP was accomplished using Nintendo's Wii Fit Plus for 40 minutes, 3 times a week for 8 weeks during the period of May 27 to July 19, 2013. Physical fitness (muscle strength, balance, flexibility), body composition (skeletal muscle mass, body fat rate, arm and leg muscle mass), and fatigue were measured at baseline and after the intervention. [Results] After the VREP, physical fitness and body composition significantly increased, and the level of fatigue significantly decreased in the exercise group. [Conclusion] These results suggest that a VREP improves physical fitness, body composition, and fatigue in HD patients. Based on the findings, VREPs should be used as a health promotion programs for HD patients.

Animal models of fibromyalgia

PubMed Central

2013-01-01

Animal models of disease states are valuable tools for developing new treatments and investigating underlying mechanisms. They should mimic the symptoms and pathology of the disease and importantly be predictive of effective treatments. Fibromyalgia is characterized by chronic widespread pain with associated co-morbid symptoms that include fatigue, depression, anxiety and sleep dysfunction. In this review, we present different animal models that mimic the signs and symptoms of fibromyalgia. These models are induced by a wide variety of methods that include repeated muscle insults, depletion of biogenic amines, and stress. All potential models produce widespread and long-lasting hyperalgesia without overt peripheral tissue damage and thus mimic the clinical presentation of fibromyalgia. We describe the methods for induction of the model, pathophysiological mechanisms for each model, and treatment profiles. PMID:24314231

Effectiveness of a group-based self-management program for people with chronic fatigue syndrome: a randomized controlled trial.

PubMed

Pinxsterhuis, Irma; Sandvik, Leiv; Strand, Elin Bolle; Bautz-Holter, Erik; Sveen, Unni

2017-01-01

To evaluate the effectiveness of a group-based self-management program for people with chronic fatigue syndrome. A randomized controlled trial. Four mid-sized towns in southern Norway and two suburbs of Oslo. A total of 137 adults with chronic fatigue syndrome. A self-management program including eight biweekly meetings of 2.5 hours duration. The control group received usual care. Primary outcome measure: Medical Outcomes Study-Short Form-36 physical functioning subscale. Fatigue severity scale, self-efficacy scale, physical and mental component summary of the Short Form-36, and the illness cognition questionnaire (acceptance subscale). Assessments were performed at baseline, and at six-month and one-year follow-ups. At the six-month follow-up, a significant difference between the two groups was found concerning fatigue severity ( p = 0.039) in favor of the control group, and concerning self-efficacy in favor of the intervention group ( p = 0.039). These significant differences were not sustained at the one-year follow-up. No significant differences were found between the groups concerning physical functioning, acceptance, and health status at any of the measure points. The drop-out rate was 13.9% and the median number of sessions attended was seven (out of eight). The evaluated self-management program did not have any sustained effect, as compared with receiving usual care.

Goals Set After Completing a Teleconference-Delivered Program for Managing Multiple Sclerosis Fatigue

PubMed Central

Asano, Miho; Preissner, Katharine; Duffy, Rose; Meixell, Maggie

2015-01-01

Setting goals can be a valuable skill to self-manage multiple sclerosis (MS) fatigue. A better understanding of the goals set by people with MS after completing a fatigue management program can assist health care professionals with tailoring interventions for clients. This study aimed to describe the focus of goals set by people with MS after a teleconference-delivered fatigue management program and to evaluate the extent to which participants were able to achieve their goals over time. In total, 485 goals were set by 81 participants. Over a follow-up period, 64 participants rated 284 goals regarding progress made toward goal achievement. Approximately 50% of the rated goals were considered achieved. The most common type of goal achieved was that of instrumental activities of daily living. Short-term goals were more likely to be achieved. This study highlights the need for and importance of promoting and teaching goal-setting skills to people with MS. PMID:25871602

Evaluating the Effectiveness of Fatigue Management Training to Improve Police Sleep Health and Wellness: A Pilot Study.

PubMed

James, Lois; Samuels, Charles H; Vincent, Fiona

2018-01-01

To evaluate the effectiveness of an intervention for improving sleep health in a sample of employees from the Royal Canadian Mounted Police (RCMP). Using a pre- and post-design we exposed 61 RCMP members to a fatigue-management training program. Pre- and post-intervention surveys included the Pittsburg Sleep Quality Index (PSQI), the World Health Organization Quality of Life (WHOQOL) instrument, and the six item index of psychological distress (Symptom Checklist-90). We found the training improved member satisfaction with sleep (Wald = 2.58; df = 1; P = 0.03) and reduced symptoms of insomnia (Wald = 5.5; df = 1; P = 0.02). Furthermore, the training reduced the incidence of headaches (Wald = 6.5; df = 1; P = 0.01). Our findings suggest that a fatigue management training program resulted in positive sleep health benefits for police. We stress the importance of continued evaluation to inform the large-scale implementation of fatigue-management programs.

The frequency and characteristics of chronic widespread pain in general practice: a case-control study.

PubMed

Rohrbeck, Jens; Jordan, Kelvin; Croft, Peter

2007-02-01

Chronic widespread pain is common in the community but is not often diagnosed in primary care. One explanation may be that widespread pain is presented and treated in primary care as multiple episodes of regional pain. To determine whether patients who consult with multiple regional pain syndromes have characteristics consistent with chronic widespread pain. Case-control study. One general practice in North Staffordshire, UK. Participants were 148 cases who consulted regularly with different musculoskeletal pains over 5 years, and 524 controls who had not consulted for musculoskeletal pain during the same period. A postal questionnaire survey and medical record review were undertaken. Cases with musculoskeletal pain reported more health problems and higher levels of fatigue than controls, and significantly worse general health and greater sleep disturbance (odds ratios 3.3. and 3.1, respectively). They generally reported more severe symptoms and consulted more frequently for a range of problems, but this was not explained by a general propensity to consult. Patients who consult in primary care with multiple regional pain syndromes have similar characteristics to those associated with chronic widespread pain and fibromyalgia. Recognising the need for general approaches to pain management, rather than treating each syndrome as a regional problem of pain, may improve the outcome in such patients.

The U.S. Commercial Air Tour Industry: A Review of Aviation Safety Concerns

PubMed Central

Ballard, Sarah-Blythe

2016-01-01

The U.S. Title 14 Code of Federal Regulations defines commercial air tours as “flight[s] conducted for compensation or hire in an airplane or helicopter where a purpose of the flight is sightseeing.” The incidence of air tour crashes in the United States is disproportionately high relative to similar commercial aviation operations, and air tours operating under Part 91 governance crash significantly more than those governed by Part 135. This paper reviews the government and industry response to four specific areas of air tour safety concern: surveillance of flight operations, pilot factors, regulatory standardization, and maintenance quality assurance. It concludes that the government and industry have successfully addressed many of these tenet issues, most notably by: advancing the operations surveillance infrastructure through implementation of en route, ground-based, and technological surveillance methods; developing Aeronautical Decision Making and cue-based training programs for air tour pilots; consolidating federal air tour regulations under Part 136; and developing public-private partnerships for raising maintenance operating standards and improving quality assurance programs. However, opportunities remain to improve air tour safety by: increasing the number and efficiency of flight surveillance programs; addressing pilot fatigue with more restrictive flight hour limitations for air tour pilots; ensuring widespread uptake of maintenance quality assurance programs, especially among high-risk operators not currently affiliated with private air tour safety programs; and eliminating the 25-mile exception allowing Part 91 operators to conduct commercial air tours without the safety oversight required of Part 135 operators. PMID:24597160

The U.S. commercial air tour industry: a review of aviation safety concerns.

PubMed

Ballard, Sarah-Blythe

2014-02-01

The U.S. Title 14 Code of Federal Regulations defines commercial air tours as "flight[s] conducted for compensation or hire in an airplane or helicopter where a purpose of the flight is sightseeing." The incidence of air tour crashes in the United States is disproportionately high relative to similar commercial aviation operations, and air tours operating under Part 91 governance crash significantly more than those governed by Part 135. This paper reviews the government and industry response to four specific areas of air tour safety concern: surveillance of flight operations, pilot factors, regulatory standardization, and maintenance quality assurance. It concludes that the government and industry have successfully addressed many of these tenet issues, most notably by: advancing the operations surveillance infrastructure through implementation of en route, ground-based, and technological surveillance methods; developing Aeronautical Decision Making and cue-based training programs for air tour pilots; consolidating federal air tour regulations under Part 136; and developing public-private partnerships for raising maintenance operating standards and improving quality assurance programs. However, opportunities remain to improve air tour safety by: increasing the number and efficiency of flight surveillance programs; addressing pilot fatigue with more restrictive flight hour limitations for air tour pilots; ensuring widespread uptake of maintenance quality assurance programs, especially among high-risk operators not currently affiliated with private air tour safety programs; and eliminating the 25-mile exception allowing Part 91 operators to conduct commercial air tours without the safety oversight required of Part 135 operators.

Exercising Impacts on Fatigue, Depression, and Paresthesia in Female Patients with Multiple Sclerosis.

PubMed

Razazian, Nazanin; Yavari, Zeinab; Farnia, Vahid; Azizi, Akram; Kordavani, Laleh; Bahmani, Dena Sadeghi; Holsboer-Trachsler, Edith; Brand, Serge

2016-05-01

Multiple sclerosis (MS) is a chronic progressive autoimmune disease impacting both body and mind. Typically, patients with MS report fatigue, depression, and paresthesia. Standard treatment consists of immune modulatory medication, though there is growing evidence that exercising programs have a positive influence on fatigue and psychological symptoms such as depression. We tested the hypothesis that, in addition to the standard immune regulatory medication, either yoga or aquatic exercise can ameliorate both fatigue and depression, and we examined whether these interventions also influence paresthesia compared with a nonexercise control condition. Fifty-four women with MS (mean age: M = 33.94 yr, SD = 6.92) were randomly assigned to one of the following conditions: yoga, aquatic exercise, or nonexercise control. Their existing immune modulatory therapy remained unchanged. Participants completed questionnaires covering symptoms of fatigue, depression, and paresthesia, both at baseline and on completion of the study 8 wk later. Compared with the nonexercise control condition and over time, fatigue, depression, and paresthesia decreased significantly in the yoga and aquatic exercise groups. On study completion, the likelihood of reporting moderate to severe depression was 35-fold higher in the nonexercise control condition than in the intervention conditions (yoga and aquatic exercising values collapsed). The pattern of results suggests that for females with MS and treated with standard immune regulatory medication, exercise training programs such as yoga and aquatic exercising positively impact on core symptoms of MS, namely, fatigue, depression, and paresthesia. Exercise training programs should be considered in the future as possible complements to standard treatments.

Development of an improved method of consolidating fatigue life data

NASA Technical Reports Server (NTRS)

Leis, B. N.; Sampath, S. G.

1978-01-01

A fatigue data consolidation model that incorporates recent advances in life prediction methodology was developed. A combined analytic and experimental study of fatigue of notched 2024-T3 aluminum alloy under constant amplitude loading was carried out. Because few systematic and complete data sets for 2024-T3 were available in the program generated data for fatigue crack initiation and separation failure for both zero and nonzero mean stresses. Consolidations of these data are presented.

Load-Differential Imaging for Detection and Localization of Fatigue Cracks Using Lamb Waves (Preprint)

DTIC Science & Technology

2012-03-01

AFRL-RX-WP-TP-2012-0278 LOAD-DIFFERENTIAL IMAGING FOR DETECTION AND LOCALIZATION OF FATIGUE CRACKS USING LAMB WAVES (PREPRINT) X. Chen...OF FATIGUE CRACKS USING LAMB WAVES (PREPRINT) 5a. CONTRACT NUMBER FA8650-09-C-5206 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6...Jan 2012. Preprint journal article to be submitted to NDT & E. This document contains color. 14. ABSTRACT Fatigue cracks are common and

[The effects of foot reflexology on fatigue and insomnia in patients suffering from coal workers' pneumoconiosis].

PubMed

Lee, Young-Mee; Sohng, Kyeong-Yae

2005-12-01

The purpose of this study was to determine the effects of foot reflexology on fatigue and insomnia in patients suffering from coal workers' pneumoconiosis. This study was a quasi-experimental study of pre-test and post-test design in a non-equivalent control group. The subjects of this study consisted of both the experimental group of twenty-nine and the control group of thirty coal workers' pneumoconiosis patients. Data was collected from December 10, 2002 to February 15, 2003. Foot reflexology was performed for 60 minutes twice a week through five weeks in the experimental group, but none in the control group. To evaluate the effects of foot reflexology, the scores of fatigue and insomnia were measured before and after the experiment in both groups. Fatigue was evaluated by Fatigue Symptoms Inventory. Insomnia was measured with the visual analogue scale (VAS). Data of this experiment was analyzed by Chi-square test, t-test, unpaired t-test and Repeated Measures ANOVA with the SAS Program. The scores of fatigue and insomnia decreased in the experimental group but not in the control group. There was a significant difference of fatigue and insomnia between the two groups. It is suggested that foot reflexology might have beneficial effects on reducing fatigue and insomnia in patients suffering from coal workers' pneumoconiosis, and can be recommended as a nursing intervention program for patients with coal workers' pneumoconiosis.

A review of fracture mechanics life technology

NASA Technical Reports Server (NTRS)

Besuner, P. M.; Harris, D. O.; Thomas, J. M.

1986-01-01

Lifetime prediction technology for structural components subjected to cyclic loads is examined. The central objectives of the project are: (1) to report the current state of the art, and (2) recommend future development of fracture mechanics-based analytical tools for modeling subcritical fatigue crack growth in structures. Of special interest is the ability to apply these tools to practical engineering problems and the developmental steps necessary to bring vital technologies to this stage. The authors conducted a survey of published literature and numerous discussions with experts in the field of fracture mechanics life technology. One of the key points made is that fracture mechanics analyses of crack growth often involve consideration of fatigue and fracture under extreme conditions. Therefore, inaccuracies in predicting component lifetime will be dominated by inaccuracies in environment and fatigue crack growth relations, stress intensity factor solutions, and methods used to model given loads and stresses. Suggestions made for reducing these inaccuracies include development of improved models of subcritical crack growth, research efforts aimed at better characterizing residual and assembly stresses that can be introduced during fabrication, and more widespread and uniform use of the best existing methods.

Fibromyalgia and chronic fatigue syndrome in children.

PubMed

Itoh, Yasuhiko; Shigemori, Tomoko; Igarashi, Tohru; Fukunaga, Yoshitaka

2012-04-01

Fibromyalgia (FM) is characterized by widespread persistent pain and the presence of multiple discrete tender points. Chronic fatigue syndrome (CFS) is a syndrome characterized by debilitating fatigue associated with a variable number of non-specific complaints. Because neither condition had necessarily been recognized in children until recently, those patients have been treated as having school refusal without being diagnosed as having either syndrome. There is a considerable overlap of clinical symptoms between these two syndromes. It is therefore controversial as to whether these syndromes have the same pathogenesis or not. The aim of the present study was to clarify the relationship between these syndromes in children. Fifteen patients with FM and 21 patients with CFS were investigated both clinically and immunologically. Immunological assessments included thorough analysis of autoantibodies using several techniques. Anti-nuclear antibody titers were higher and the prevalence of anti-Sa antibody was far more frequent in CFS patients than in FM patients. CFS and FM are different from each other at least in childhood, from an immunological aspect, although some patients could have both conditions. © 2011 The Authors. Pediatrics International © 2011 Japan Pediatric Society.

A review of fracture mechanics life technology

NASA Technical Reports Server (NTRS)

Thomas, J. M.; Besuner, P. M.; Harris, D. O.

1985-01-01

Current lifetime prediction technology for structural components subjected to cyclic loads was reviewed. The central objectives of the project were to report the current state of and recommend future development of fracture mechanics-based analytical tools for modeling and forecasting subcritical fatigue crack growth in structures. Of special interest to NASA was the ability to apply these tools to practical engineering problems and the developmental steps necessary to bring vital technologies to this stage. A survey of published literature and numerous discussions with experts in the field of fracture mechanics life technology were conducted. One of the key points made is that fracture mechanics analyses of crack growth often involve consideration of fatigue and fracture under extreme conditions. Therefore, inaccuracies in predicting component lifetime will be dominated by inaccuracies in environment and fatigue crack growth relations, stress intensity factor solutions, and methods used to model given loads and stresses. Suggestions made for reducing these inaccuracies include: development of improved models of subcritical crack growth, research efforts aimed at better characterizing residual and assembly stresses that can be introduced during fabrication, and more widespread and uniform use of the best existing methods.

Role of central sensitization in symptoms beyond muscle pain, and the evaluation of a patient with widespread pain.

PubMed

Yunus, Muhammad B

2007-06-01

Patients with widespread pain or fibromyalgia syndrome have many symptoms besides musculoskeletal pain: e.g. fatigue, sleep difficulties, a swollen feeling in tissues, paresthesia, cognitive dysfunction, dizziness, and symptoms of overlapping conditions such as irritable bowel syndrome, headaches and restless legs syndrome. There is evidence for central sensitization in these conditions, but further studies are needed. Anxiety, stress and depression are also present in 30-45% of patients. Other factors that may contribute to symptoms include endocrine dysfunction, psychosocial distress, trauma, and disrupted sleep. Evaluation of a patient presenting with widespread pain includes history and physical examination to diagnose both fibromyalgia and associated or concomitant conditions. Fibromyalgia should be diagnosed by its own characteristic features. Some patients with otherwise typical symptoms of fibromyalgia may have as few as four to six tender points in clinical practice. Patients with rheumatoid arthritis and systemic lupus erythematosus should be evaluated for fibromyalgia, since 20-30% of them have associated fibromyalgia, requiring a different treatment approach.

Elevated temperature biaxial fatigue

NASA Technical Reports Server (NTRS)

Jordan, E. H.

1984-01-01

A three year experimental program for studying elevated temperature biaxial fatigue of a nickel based alloy Hastelloy-X has been completed. A new high temperature fatigue test facility with unique capabilities has been developed. Effort was directed toward understanding multiaxial fatigue and correlating the experimental data to the existing theories of fatigue failure. The difficult task of predicting fatigue lives for non-proportional loading was used as an ultimate test for various life prediction methods being considered. The primary means of reaching improved undertanding were through several critical non-proportional loading experiments. It was discovered that the cracking mode switched from primarily cracking on the maximum shear planes at room temperature to cracking on the maximum normal strain planes at 649 C.

Experimental and theoretical investigation of fatigue life in reusable rocket thrust chambers

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Kasper, H. J.; Pavli, A. J.

1976-01-01

During a test program to investigate low-cycle thermal fatigue, 13 rocket combustion chambers were fabricated and cyclically test fired to failure. Six oxygen-free, high-conductivity (OFHC) copper and seven Amzirc chambers were tested. The chamber liners were fabricated of copper or copper alloy and contained milled coolant channels. The chambers were completed by means of an electroformed nickel closeout. The oxidant/fuel ratio for the liquid oxygen and gaseous hydrogen propellants was 6.0. The failures in the OFHC copper chambers were not typical fatigue failures but are described as creep rupture enhanced by ratcheting. The coolant channels bulged toward the chamber centerline, resulting in progressive thinning of the wall during each cycle. The failures in the Amzirc alloy chambers were caused by low-cycle thermal fatigue. The lives were much shorter than were predicted by an analytical structural analysis computer program used in conjunction with fatigue life data from isothermal test specimens, due to the uneven distribution of Zr in the chamber material.

Lifetime Reliability Evaluation of Structural Ceramic Parts with the CARES/LIFE Computer Program

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Powers, Lynn M.; Janosik, Lesley A.; Gyekenyesi, John P.

1993-01-01

The computer program CARES/LIFE calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/or proof test loading. This program is an extension of the CARES (Ceramics Analysis and Reliability Evaluation of Structures) computer program. CARES/LIFE accounts for the phenomenon of subcritical crack growth (SCG) by utilizing the power law, Paris law, or Walker equation. The two-parameter Weibull cumulative distribution function is used to characterize the variation in component strength. The effects of multiaxial stresses are modeled using either the principle of independent action (PIA), Weibull's normal stress averaging method (NSA), or Batdorf's theory. Inert strength and fatigue parameters are estimated from rupture strength data of naturally flawed specimens loaded in static, dynamic, or cyclic fatigue. Two example problems demonstrating cyclic fatigue parameter estimation and component reliability analysis with proof testing are included.

Chronic widespread musculoskeletal pain, fatigue, depression and disordered sleep in chronic post-SARS syndrome; a case-controlled study.

PubMed

Moldofsky, Harvey; Patcai, John

2011-03-24

The long term adverse effects of Severe Acute Respiratory Syndrome (SARS), a viral disease, are poorly understood. Sleep physiology, somatic and mood symptoms of 22 Toronto subjects, 21 of whom were healthcare workers, (19 females, 3 males, mean age 46.29 yrs.+/- 11.02) who remained unable to return to their former occupation (mean 19.8 months, range: 13 to 36 months following SARS) were compared to 7 healthy female subjects. Because of their clinical similarities to patients with fibromyalgia syndrome (FMS) these post-SARS subjects were similarly compared to 21 drug free female patients, (mean age 42.4 +/- 11.8 yrs.) who fulfilled criteria for fibromyalgia. Chronic post-SARS is characterized by persistent fatigue, diffuse myalgia, weakness, depression, and nonrestorative sleep with associated REM-related apneas/hypopneas, an elevated sleep EEG cyclical alternating pattern, and alpha EEG sleep anomaly. Post- SARS patients had symptoms of pre and post-sleep fatigue and post sleep sleepiness that were similar to the symptoms of patients with FMS, and similar to symptoms of patients with chronic fatigue syndrome. Both post-SARS and FMS groups had sleep instability as indicated by the high sleep EEG cyclical alternating pattern rate. The post-SARS group had a lower rating of the alpha EEG sleep anomaly as compared to the FMS patients. The post-SARS group also reported less pre-sleep and post-sleep musculoskeletal pain symptoms. The clinical and sleep features of chronic post-SARS form a syndrome of chronic fatigue, pain, weakness, depression and sleep disturbance, which overlaps with the clinical and sleep features of FMS and chronic fatigue syndrome.

Stress Corrosion-Cracking and Corrosion Fatigue Impact of IZ-C17+ Zinc Nickel on 4340 Steel

DTIC Science & Technology

2017-05-17

REPORT NO: NAWCADPAX/TIM-2016/189 STRESS CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL by...CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL by Craig Matzdorf Charles Lei Matt Stanley...5a. CONTRACT NUMBER STRESS CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL 5b. GRANT NUMBER 5c. PROGRAM

Orbit Transfer Rocket Engine Technology Program. Automated Preflight Methods Concept Definition. Task E.7

DTIC Science & Technology

1991-12-21

itself. For example, in the case of turbine wheel /blade inspection, remotely obtained blade fatigue data coupled with a life prediction model and...Security, etc. C 2. T/C Assembly for Evidence of Coolant Passage Blockage C 3. HPFTP Turbine Wheel /Blades for Cracks, Fatigue and Damage C 4. HPOTP Turbine... Wheel /Blades for Cracks, Fatigue and Damage C 5. LPFTP Turbine Wheel /Blades for Cracks, Fatigue and Damage C 6. LPOTP Turbine Wheel /Blades for Cracks

Impact of a 10-Week Individualized Exercise Program on Physical Function and Fatigue of People with Multiple Sclerosis

PubMed Central

Elgelid, Staffan; Bolger, Shannon; Parsons, Caroline; Quashnoc, Rachel; Raymor, Johanna

2011-01-01

Research has found that people with multiple sclerosis (MS) who engage in exercise programs experience improvements in physical and psychological health, resulting in enhanced quality of life. These studies have involved structured exercise protocols, but few have examined the effects of an individualized exercise program allowing for peer socialization. The purpose of this study was to investigate the effects of a 10-week individualized exercise program offering opportunities to socialize with peers on fatigue and physical functioning in people with MS. Thirteen individuals with a physician diagnosis of MS were enrolled in a 10-week exercise program at Nazareth College in Rochester, New York. Eleven participants (9 female, 2 male; mean ± SD age, 55.0 ± 7.06 years) completed the study. The following qualitative and quantitative measures were used for evaluation before and after the exercise program: Multiple Sclerosis Quality of Life–54 (MSQOL-54), Activities-specific Balance Confidence (ABC) scale, Modified Fatigue Impact Scale (MFIS), Timed Up and Go (TUG) test, Timed 10-Meter Walk (T10MW) test, functional reach test, and single-leg stance (SLS) test. Statistically significant differences were found for the TUG (P = .005), T10MW (P = .014), and MFIS physical functioning subscore (P = .039). The results showed significant increases in gait speed and mobility as well as decreased impact of fatigue on physical functioning after the 10-week exercise program. PMID:24453715

Time-dependent reliability analysis of ceramic engine components

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.

1993-01-01

The computer program CARES/LIFE calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/or proof test loading. This program is an extension of the CARES (Ceramics Analysis and Reliability Evaluation of Structures) computer program. CARES/LIFE accounts for the phenomenon of subcritical crack growth (SCG) by utilizing either the power or Paris law relations. The two-parameter Weibull cumulative distribution function is used to characterize the variation in component strength. The effects of multiaxial stresses are modeled using either the principle of independent action (PIA), the Weibull normal stress averaging method (NSA), or the Batdorf theory. Inert strength and fatigue parameters are estimated from rupture strength data of naturally flawed specimens loaded in static, dynamic, or cyclic fatigue. Two example problems demonstrating proof testing and fatigue parameter estimation are given.

Reciprocal relationship between acute stress and acute fatigue in everyday life in a sample of university students.

PubMed

Doerr, Johanna M; Ditzen, Beate; Strahler, Jana; Linnemann, Alexandra; Ziemek, Jannis; Skoluda, Nadine; Hoppmann, Christiane A; Nater, Urs M

2015-09-01

We investigated whether stress may influence fatigue, or vice versa, as well as factors mediating this relationship. Fifty healthy participants (31 females, 23.6±3.2 years) completed up to 5 momentary assessments of stress and fatigue during 5 days of preparation for their final examinations (exam condition) and 5 days of a regular semester week (control condition). Sleep quality was measured by self-report at awakening. A sub-group of participants (n=25) also collected saliva samples. Fatigue was associated with concurrent stress, stress reported at the previous measurement point, and previous-day stress. However, momentary stress was also predicted by concurrent fatigue, fatigue at the previous time point, and previous-day fatigue. Sleep quality mediated the association between stress and next-day fatigue. Cortisol and alpha-amylase did not mediate the stress-fatigue relationship. In conclusion, there is a reciprocal stress-fatigue relationship. Both prevention and intervention programs should comprehensively cover how stress and fatigue might influence one another. Copyright © 2015 Elsevier B.V. All rights reserved.

Effectiveness of a Scaled-Up Arthritis Self-Management Program in Oregon: Walk With Ease.

PubMed

Conte, Kathleen P; Odden, Michelle C; Linton, Natalie M; Harvey, S Marie

2016-12-01

To evaluate the effectiveness of Walk With Ease (WWE), an evidence-based arthritis self-management program that was scaled up in Oregon in 2012 to 2014. Guided by the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) framework, we collected participant surveys and attendance records and conducted observations. Preprogram and postprogram, participants self-reported pain and fatigue (scale: 0-10 points; high scores indicate more pain and fatigue) and estimated episodes of physical activity per week in the last month. Recruitment successfully reached the targeted population-sedentary adults with arthritis (n = 598). Participants reported significant reduction in pain (-0.47 points; P = .006) and fatigue (-0.58 points; P = .021) and increased physical activity (0.86 days/week; P < .001). WWE was adopted by workplaces and medical, community, faith, and retirement centers. Most WWE programs were delivered with high fidelity; average attendance was 47%. WWE is suitable for implementation by diverse organizations. Effect sizes for pain and fatigue were less than those in the original WWE studies, but this is to be expected for a large-scale implementation. Public Health Implications. WWE can be effectively translated to diverse, real-world contexts to help sedentary adults increase physical activity and reduce pain and fatigue.

Improved cognitive functioning in obese adolescents after a 30-week inpatient weight loss program.

PubMed

Vantieghem, Stijn; Bautmans, Ivan; Guchtenaere, Ann De; Tanghe, Ann; Provyn, Steven

2018-06-15

Studies linked obesity with a large number of medical conditions including decreased cognitive functioning. The relation between BMI and cognition was proven in adults, but in adolescents the results are conflicting. Further, limited data are available on the impact of weight loss on cognition. This study analyzed the impact of a 30-week lasting weight loss program on cognition and determined the impact of changes in body composition and self-perceived fatigue on changes in cognition. Sixty-two obese adolescents were evaluated at baseline and after 30 weeks. Stroop test (ST; selective attention), Continuous Performance Test (CPT; sustained attention) and Ray Auditory verbal learning test (RAVLT; short-term memory) were assessed. Additionally, body composition parameters and fatigue (MFI-20) were evaluated. Improved reaction times were found for ST and CPT after the intervention, but were independent for reductions in BMI, fat mass, fat%, and fatigue. Short memory also improved with decreased fatigue as an influencing parameter. Accuracy of ST and CPT showed no significant changes. A 30-week lasting inpatient weight loss program improved selective attention, sustained attention, and short-term memory. Changes in body composition did not explain the improvements in cognitive functioning. Decreased fatigue resulted in improved aspects of cognition.

Physical training in children with osteogenesis imperfecta.

PubMed

Van Brussel, Marco; Takken, Tim; Uiterwaal, Cuno S P M; Pruijs, Hans J; Van der Net, Janjaap; Helders, Paul J M; Engelbert, Raoul H H

2008-01-01

To study the effects of a physical training program on exercise capacity, muscle force, and subjective fatigue levels in patients with mild to moderate forms of osteogenesis imperfecta (OI). Thirty-four children with OI type I or IV were randomly assigned to either a 12-week graded exercise program or care as usual for 3 months. Exercise capacity and muscle force were studied; subjective fatigue, perceived competence, and health-related quality of life were secondary outcomes. All outcomes were measured at baseline (T = 0), after intervention (T = 1), and after 6 and 9 months (T = 2 and T = 3, respectively). After intervention (T = 1), peak oxygen consumption (VO2peak), relative VO2peak (VO2peak/kg), maximal working capacity (Wmax), and muscle force were significantly improved (17%, 18%, 10%, and 12%, respectively) compared with control values. Subjective fatigue decreased borderline statistically significantly. Follow-up at T = 2 showed a significant decrease of the improvements measured at T = 1 of VO2peak, but VO2peak/kg, Wmax, and subjective fatigue showed no significant difference. At T = 3, we found a further decrease of the gained improvements. A supervised training program can improve aerobic capacity and muscle force and reduces levels of subjective fatigue in children with OI type I and IV in a safe and effective manner.

High Cycle Fatigue (HCF) Science and Technology Program 2000 Annual Report

DTIC Science & Technology

2000-01-01

in an area of deep compressive stress. • Results of industry and government testing have indicated the ability to stop crack initiation and...fatigue crack nucleation process with the cyclic deformation behavior of the alloy for different microstructures and crystallographic texture ... texture combinations investigated, bimodal fine uni-rolled and lamellar cross-rolled displayed superior fatigue properties to the remaining four

Acoustic fatigue life prediction for nonlinear structures with multiple resonant modes

NASA Technical Reports Server (NTRS)

Miles, R. N.

1992-01-01

This report documents an effort to develop practical and accurate methods for estimating the fatigue lives of complex aerospace structures subjected to intense random excitations. The emphasis of the current program is to construct analytical schemes for performing fatigue life estimates for structures that exhibit nonlinear vibration behavior and that have numerous resonant modes contributing to the response.

Effect of Fatigue Protocols on Lower Limb Neuromuscular Function and Implications for Anterior Cruciate Ligament Injury Prevention Training: A Systematic Review.

PubMed

Barber-Westin, Sue D; Noyes, Frank R

2017-12-01

Approximately two-thirds of anterior cruciate ligament (ACL) tears are sustained during noncontact situations when an athlete is cutting, pivoting, decelerating, or landing from a jump. Some investigators have postulated that fatigue may result in deleterious alterations in lower limb biomechanics during these activities that could increase the risk of noncontact ACL injuries. However, prior studies have noted a wide variation in fatigue protocols, athletic tasks studied, and effects of fatigue on lower limb kinetics and kinematics. First, to determine if fatigue uniformly alters lower limb biomechanics during athletic tasks that are associated with noncontact ACL injuries. Second, to determine if changes should be made in ACL injury prevention training programs to alter the deleterious effects of fatigue on lower limb kinetics and kinematics. Systematic review; Level of evidence, 4. A systematic review of the literature using MEDLINE was performed. Key terms were fatigue, neuromuscular, exercise, hop test, and single-legged function tests. Inclusion criteria were original research studies involving healthy participants, use of a fatigue protocol, study of at least 1 lower limb task that involved landing from a hop or jump or cutting, and analysis of at least 1 biomechanical variable. Thirty-seven studies involving 806 athletes (485 female, 321 male; mean age, 22.7 years) met the inclusion criteria. General fatigue protocols were used in 20 investigations, peripheral protocols were used in 17 studies, and 21 different athletic tasks were studied (13 single-legged, 8 double-legged). There was no consistency among investigations regarding the effects of fatigue on hip, knee, or ankle joint angles and moments or surface electromyography muscle activation patterns. The fatigue protocols typically did not produce statistically significant changes in ground-reaction forces. Published fatigue protocols did not uniformly produce alterations in lower limb neuromuscular factors that heighten the risk of noncontact ACL injuries. Therefore, justification does not currently exist for major changes in ACL injury prevention training programs to account for potential fatigue effects. However, the effect of fatigue related to ACL injuries is worthy of further investigation, including the refinement of protocols and methods of analysis.

Small Crack Growth and Fatigue Life Predictions for High-Strength Aluminium Alloys. Part 1; Experimental and Fracture Mechanics Analysis

NASA Technical Reports Server (NTRS)

Wu, X. R.; Newman, J. C.; Zhao, W.; Swain, M. H.; Ding, C. F.; Phillips, E. P.

1998-01-01

The small crack effect was investigated in two high-strength aluminium alloys: 7075-T6 bare and LC9cs clad alloy. Both experimental and analytical investigations were conducted to study crack initiation and growth of small cracks. In the experimental program, fatigue tests, small crack and large crack tests A,ere conducted under constant amplitude and Mini-TWIST spectrum loading conditions. A pronounced small crack effect was observed in both materials, especially for the negative stress ratios. For all loading conditions, most of the fatigue life of the SENT specimens was shown to be crack propagation from initial material defects or from the cladding layer. In the analysis program, three-dimensional finite element and A weight function methods were used to determine stress intensity factors and to develop SIF equations for surface and corner cracks at the notch in the SENT specimens. A plastisity-induced crack-closure model was used to correlate small and large crack data, and to make fatigue life predictions, Predicted crack-growth rates and fatigue lives agreed well with experiments. A total fatigue life prediction method for the aluminum alloys was developed and demonstrated using the crack-closure model.

A comparison of the effects of exercises plus connective tissue massage to exercises alone in women with fibromyalgia syndrome: a randomized controlled trial.

PubMed

Toprak Celenay, Seyda; Anaforoglu Kulunkoglu, Bahar; Yasa, Mustafa Ertugrul; Sahbaz Pirincci, Cansu; Un Yildirim, Necmiye; Kucuksahin, Orhan; Ugurlu, Fatma Gulcin; Akkus, Selami

2017-11-01

This study aimed to compare the effectiveness of a 6-week combined exercise program with and without connective tissue massage (CTM) on pain, fatigue, sleep problem, health status, and quality of life in patients with fibromyalgia syndrome (FMS). Patients were randomly allocated into Exercise (n = 20) and Exercise + CTM (n = 20) groups. The exercise program with and without CTM was carried out 2 days a week for 6 weeks. Pain, fatigue, sleep problem with Visual Analog Scales, health status with Fibromyalgia Impact Questionnaire (FIQ), and quality of life with Short Form-36 were evaluated. After the program, pain, fatigue and sleep problem reduced, health status (except of the scores of FIQ-1 and FIQ-10), physical functioning, role limitations due to physical health, bodily pain, role limitations due to emotional health, vitality, and general health perceptions parameters related to quality of life improved in the Exercise group, (P < 0.05). In the Exercise + CTM group, pain, fatigue and sleep problem decreased, health status and quality of life improved (P < 0.05). Pain, fatigue, sleep problem, and role limitations due to physical health improved in the Exercise + CTM group in comparison to the Exercise group (P < 0.05). The study suggested that exercises with and without CTM might be effective for decreasing pain, fatigue and sleep problem whereas increasing health status and quality of life in patients with FMS. However, exercises with CTM might be superior in improving pain, fatigue, sleep problem, and role limitations due to physical health compared to exercise alone.

Structural Technology Evaluation Analysis Program (STEAP). Task Order 0029: Thermal Stability of Fatigue Life-Enhanced Structures

DTIC Science & Technology

2012-01-01

and c, we were able to obtain Figure 21: Intensity and Pressure Temporal Profiles Calculated from Pressure Model 0 20 40 60 80 100 0 2 4 6 8...August 2008 – 31 January 2012 4 . TITLE AND SUBTITLE STRUCTURAL TECHNOLOGY EVALUATION ANALYSIS PROGRAM (STEAP) Task Order 0029: Thermal...Stability of Fatigue Life-Enhanced Structures 5a. CONTRACT NUMBER FA8650-04-D-3446-0029 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62201F 6

Fatigue and fracture: Overview

NASA Technical Reports Server (NTRS)

Halford, G. R.

1984-01-01

A brief overview of the status of the fatigue and fracture programs is given. The programs involve the development of appropriate analytic material behavior models for cyclic stress-strain-temperature-time/cyclic crack initiation, and cyclic crack propagation. The underlying thrust of these programs is the development and verification of workable engineering methods for the calculation, in advance of service, of the local cyclic stress-strain response at the critical life governing location in hot section compounds, and the resultant crack initiation and crack growth lifetimes.

Fibromyalgia and Myofascial Pain Syndrome-A Dilemma

PubMed Central

Chandola, H C; Chakraborty, Arunangshu

2009-01-01

Summary Pain and fatigue associated to the musculoskeletal system are among the leading causes of patients to visit their physicians and nearly one-third of such patients suffer from fibromyalgia. Fibromyalgia syndrome (FMS) is a chronic debilitating disorder characterized by widespread pain with tenderness in specific areas, leading to fatigue, headache and sleep disorder. Myofascial Pain Syndrome (MPS), is also a localized musculoskeletal pain producing condition whose diagnostic and management criteria differ from FMS but still considered by many only a subtype of FMS. Till date no exact cause has been held responsible for these painful conditions, therefore treatment of these disorders is always a challenge. The therapies are not precise but multimodal including pharmacological and alternative approaches. This article describes the existing knowledge pertaining to these conditions in regard of causative factors diagnosis and management. PMID:20640108

Corrosion fatigue of high strength fastener materials in seawater. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tipton, D.G.

1983-12-01

Environmental effects can significantly reduce the fatigue life of metals. As such, corrosion fatigue is a major concern in the engineering application of high strength fasteners in marine environments. The corrosion fatigue failure of an AISI 41L40 high strength steel blade-to-hub attachment bolt at the MOD-0A 200 kW wind turbine generator in Oahu, Hawaii prompted the current test program. Tests were undertaken to confirm the dramatic reduction of fatigue strength of AISI 41L40 in marine environments and to obtain similar corrosion fatigue data for candidate replacement materials. AISI 41L40, AISI 4140, PH 13-8Mo stainless steel, alloy 718 and alloy MP-35Nmore » were tested in axial fatigue at a frequency of 20 Hz in dry air and natural seawater. The fatigue data were fitted by regression equations to allow determination of fatigue strength for a given number of cycles to failure.« less

The Mechanical Property Data Base from an Air Force/Industry Cooperative Test Program on Advanced Aluminum Alloys

DTIC Science & Technology

1993-12-01

Longitudinal) E3 Fatigue Crack Growth Rate Data for Alcan 8090-T8 160 1 " x 4" Extrusion ( L-T Orientation). Grumman E4 Fatigue Crack Growth Rate...Data for Alcan 8090-T8 161 1 " x 4" Extrusion (T-L Orientation). Grumman E5 Fatigue Crack Growth Rate Data for Alcan 8090-T651 162 1 "x 4" Extrusion (L-T...Orientation). Northrop E6 Fatigue Crack Growth Rate for Alcan 8090-T651 163 1 " x 4" Extrusion (T-L Orientation). Northrop E7 Fatigue Crack Growth Rate

Effects of a dance-based aquatic exercise program in obese postmenopausal women with knee osteoarthritis: a randomized controlled trial.

PubMed

Casilda-López, Jesús; Valenza, Marie Carmen; Cabrera-Martos, Irene; Díaz-Pelegrina, Ana; Moreno-Ramírez, Maria Paz; Valenza-Demet, Gerald

2017-07-01

To evaluate the effects of a dance-based aquatic exercise program on functionality, cardiorespiratory capacity, postexercise heart rate, and fatigue in obese postmenopausal women with knee osteoarthritis. A randomized controlled trial was performed. In all, 34 obese women diagnosed with knee osteoarthritis participated. Women were randomly allocated to an experimental group (n = 17) or a control group (n = 17). Participants in the experimental group were included in an 8-week dance-based aquatic exercise program conducted in community swimming pools. Those in the control group underwent a global aquatic exercise program. The primary outcome measure was functionality assessed with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes were cardiorespiratory capacity evaluated with the 6-minute walk test, and postexercise heart rate and fatigue assessed using a visual analog scale. Variables were measured at baseline, after the intervention, and at 3-month follow-up. A between-group analysis showed significant postintervention differences in functionality (aggregate postintervention WOMAC score of 37.30 ± 16.61 vs 41.83 ± 13.69; P = 0.048) in favor of the experimental group. In addition, significant between-group differences were found after the 8 weeks in cardiorespiratory capacity, postexercise heart rate, and fatigue. Follow-up continued to show significant differences between groups in function (aggregate WOMAC score of 38.60 ± 13.61 vs 42.60 ± 9.05; P = 0.038), postexercise heart rate, and fatigue. An 8-week dance-based exercise program significantly improved function and cardiorespiratory capacity, and decreased postexercise heart rate and fatigue. Most of these improvements were maintained at 3-month follow-up in obese postmenopausal women.

Effects of exercise, patient education, and resource support on women with fibromyalgia: An extended long-term study.

PubMed

Karper, William B

2016-01-01

This research examined whether a long-term, multi-component program positively affected physical fitness, pain and fatigue in seven women with fibromyalgia syndrome. These women lived independently in the community. They attended a university-based program 3 days per week, 1 hour per session, year-around for many years. They were evaluated periodically with a fitness test and rating scale regarding pain and fatigue. Results from when they began the program versus most recently are provided. All of these women showed various positive results from participation in the program.

Elevated temperature biaxial fatigue

NASA Technical Reports Server (NTRS)

Jordan, E. H.

1983-01-01

Biaxial fatigue is often encountered in the complex thermo-mechanical loadings present in gas turbine engines. Engine strain histories can involve non-constant temperature, mean stress, creep, environmental effects, both isotropic and anisotropic materials and non-proportional loading. Life prediction for the general case involving all the above factors is not a practicable research project. The current research program is limited to isothermal fatigue at room temperature and 1200 F of Hastalloy-X for both proportional and non-proportional loading. An improved method for predicting the fatigue life and deformation response under biaxial cycle loading is sought.

Compassion fatigue and burnout: prevalence among oncology nurses.

PubMed

Potter, Patricia; Deshields, Teresa; Divanbeigi, Joyce; Berger, Julie; Cipriano, Doreen; Norris, Lori; Olsen, Sarah

2010-10-01

This descriptive, cross-sectional survey was conducted in inpatient nursing units and outpatient clinics in a cancer center in the midwestern United States. The sample of 153 healthcare providers included RNs, medical assistants, and radiology technicians. The fourth revision of the 30-item Professional Quality of Life (ProQOL R-IV) scale was used for measuring compassion fatigue, compassion satisfaction, and burnout. A series of cross tab analyses examined the relationship between participant demographics and three ProQOL R-IV subscales. The study sample scored similarly on compassion satisfaction and burnout when compared with participants who used the ProQOL R-IV in previous studies. Value exists in analyzing the prevalence of burnout and compassion fatigue among oncology healthcare providers. Understanding the needs of distinct demographic groups offers valuable direction for intervention program development. Applying internal evidence in the design of a relevant stress-reduction program will better equip healthcare providers to recognize and manage compassion fatigue and burnout.

Does freezing and dynamic flexing of frozen branches impact the cavitation resistance of Malus domestica and the Populus clone Walker?

PubMed

Christensen-Dalsgaard, Karen K; Tyree, Melvin T

2013-11-01

Frost damage to the xylem conduits of trees is a phenomenon of eco-physiological importance. It is often documented in terms of the percentage loss of conductivity (PLC), an indicator of air filling of the conduits. However, trees that refill their conduits in spring could be impacted more by damage to the conduits that reduce cavitation resistance, making them more susceptible to future drought events. We investigated whether ice formation, dynamic flexing of frozen branches or freeze-thaw events could reduce the cavitation resistance (cause "frost fatigue") in first-year shoots of apple (Malus domestica) and clonal hybrid cottonwood (Walker). Frost fatigue was measured in terms of P50 (the negative xylem pressure required to cause a 50 % loss of conductivity). All treatment groups showed significant frost fatigue, with the exception of the pre-flushed, constantly frozen poplar branches. The P50 following freeze treatments was approximately 50 % of the pre-freeze values. The effect tended to be greater in freeze-thawed branches. Dynamic bending of the branches had no effect on either PLC or P50. In three out of four cases, there was a significant correlation between P50 and PLC. Frost fatigue occurred in both apple and poplar, two unrelated species with different drought and frost tolerances, suggesting that it may be a widespread phenomenon that could impact the ecophysiology of temperate forests.

Acoustic fatigue: Overview of activities at NASA Langley

NASA Technical Reports Server (NTRS)

Mixson, John S.; Roussos, Louis A.

1987-01-01

A number of aircraft and spacecraft configurations are being considered for future development. These include high-speed turboprop aircraft, advanced vertical take-off and landing fighter aircraft, and aerospace planes for hypersonic intercontinental cruise or flight to orbit and return. Review of the acoustic environment expected for these vehicles indicates levels high enough that acoustic fatigue must be considered. Unfortunately, the sonic fatique design technology used for current aircraft may not be adequate for these future vehicles. This has resulted in renewed emphasis on acoustic fatigue research at the NASA Langley Research Center. The overall objective of the Langley program is to develop methods and information for design of aerospace vehicles that will resist acoustic fatigue. The program includes definition of the acoustic loads acting on structures due to exhaust jets of boundary layers, and subsequent determination of the stresses within the structure due to these acoustic loads. Material fatigue associated with the high frequency structural stress reversal patterns resulting from acoustic loadings is considered to be an area requiring study, but no activity is currently underway.

Characteristics of visual fatigue under the effect of 3D animation.

PubMed

Chang, Yu-Shuo; Hsueh, Ya-Hsin; Tung, Kwong-Chung; Jhou, Fong-Yi; Lin, David Pei-Cheng

2015-01-01

Visual fatigue is commonly encountered in modern life. Clinical visual fatigue characteristics caused by 2-D and 3-D animations may be different, but have not been characterized in detail. This study tried to distinguish the differential effects on visual fatigue caused by 2-D and 3-D animations. A total of 23 volunteers were subjected to accommodation and vergence assessments, followed by a 40-min video game program designed to aggravate their asthenopic symptoms. The volunteers were then assessed for accommodation and vergence parameters again and directed to watch a 5-min 3-D video program, and then assessed again for the parameters. The results support that the 3-D animations caused similar characteristics in vision fatigue parameters in some specific aspects as compared to that caused by 2-D animations. Furthermore, 3-D animations may lead to more exhaustion in both ciliary and extra-ocular muscles, and such differential effects were more evident in the high demand of near vision work. The current results indicated that an arbitrary set of indexes may be promoted in the design of 3-D display or equipments.

Men exhibit greater fatigue resistance than women in alternated bench press and leg press exercises.

PubMed

Monteiro, Estêvão R; Steele, James; Novaes, Jefferson S; Brown, Amanda F; Cavanaugh, Mark T; Vingren, Jakob L; Behm, David G

2017-11-17

The purpose of this study was to evaluate the influence of sex, exercise order, and rest interval on neuromuscular fatigue resistance for an alternated strength training sequence of bench press (BP) and leg press (LP) exercises. Twelve women and 16 men, both recreationally trained, performed four sessions in a random order: 1) BP followed by LP with three-minutes rest (BP+LP with rest), 2) LP followed by BP with three-minutes rest (LP+BP with rest), 3) BP followed by LP without rest interval (BP+LP no rest), and 4) LP followed by BP without rest interval (LP+BP no rest). Participants performed four sets with 100% of 10RM load to concentric failure with the goal of completing the maximum number of repetitions in both exercises. The fatigue index was analyzed from the first and last sets of each exercise bout. A main effect for sex showed that women exhibited 25.5% (p=0.001) and 24.5% (p=0.001) greater BP and LP fatigue than men respectively when performing 10RM. Men exhibited greater BP (p<0.0001; 34.1%) and LP (p<0.0001; 30.5%) fatigue resistance when a rest period was provided. Men did not show an exercise order effect for BP fatigue and exhibited greater (p=0.0003; 14.5%) LP fatigue resistance when BP was performed first. The present study demonstrated the greater fatigue resistance of men when performing 10RM BP and LP exercises. Since men tend to experience less fatigue with the second exercise in the exercise pairing, women's training programs should be adjusted to ensure they do not parallel men's resistance training programs.

Relationships between compassion fatigue, burnout, and turnover intention in Korean hospital nurses.

PubMed

Sung, Kiwol; Seo, Youngsook; Kim, Jee Hee

2012-12-01

This study aimed to identify relationships between compassion fatigue, burnout, and turnover intention in Korean hospital nurses. In total, 142 hospital nurses were surveyed as part of data collection. Data related to compassion fatigue, burnout, and turnover intention were collected using a questionnaire between May 2011 and September 2011. The data analysis was performed using PASW 19.0 program, which included one-way ANOVA, independent t-tests, Pearson's correlation coefficient, and hierarchical regression analysis. This study detected a positive correlation between compassion fatigue and burnout(r=.37, p<.001), and turnover intention(r=.55, p<.001). Compassion fatigue accounted for 29.6% of the variance for turnover intention among Korean hospital nurses. The results indicate that it is necessary to reduce compassion fatigue, and turnover intention among Korean hospital nurses.

Probabilistic Fatigue Damage Program (FATIG)

NASA Technical Reports Server (NTRS)

Michalopoulos, Constantine

2012-01-01

FATIG computes fatigue damage/fatigue life using the stress rms (root mean square) value, the total number of cycles, and S-N curve parameters. The damage is computed by the following methods: (a) traditional method using Miner s rule with stress cycles determined from a Rayleigh distribution up to 3*sigma; and (b) classical fatigue damage formula involving the Gamma function, which is derived from the integral version of Miner's rule. The integration is carried out over all stress amplitudes. This software solves the problem of probabilistic fatigue damage using the integral form of the Palmgren-Miner rule. The software computes fatigue life using an approach involving all stress amplitudes, up to N*sigma, as specified by the user. It can be used in the design of structural components subjected to random dynamic loading, or by any stress analyst with minimal training for fatigue life estimates of structural components.

Work, eat and sleep: towards a healthy ageing at work program offshore.

PubMed

Riethmeister, Vanessa; Brouwer, Sandra; van der Klink, Jac; Bültmann, Ute

2016-02-09

Health management tools need to be developed to foster healthy ageing at work and sustain employability of ageing work-forces. The objectives of this study were to 1) perform a needs assessment to identify the needs of offshore workers in the Dutch Continental Shelf with regard to healthy ageing at work and 2) to define suitable program objectives for a future healthy ageing at work program in the offshore working population. A mixed methods design was used applying an intervention mapping procedure. Qualitative data were gathered in N = 19 semi-structured interviews and six focus-group sessions (N = 49). Qualitative data were used to develop a questionnaire, which was administered among N = 450 offshore workers. Subgroup analyses were performed to investigate age-related differences relating to health status and work-related factors. The importance of good working environments, food, as well as sleep/fatigue management was identified by the qualitative data analysis. A total of 260 offshore workers completed the questionnaire. Significant differences in work ability were found between offshore workers aged <45 and 45-54 years (mean 8.63 vs. 8.19; p = 0.005) and offshore workers aged <45 and >55 years (mean 8.63 vs. 8.22; p = 0.028). Offshore workers had a high BMI (M = 27.06, SD = 3.67), with 46 % classified as overweight (BMI 25-30) and 21 % classified as obese (BMI >30). A significant difference in BMI was found between offshore workers aged <45 and ≥55 years (mean 26.3 vs. 28.6; p <0.001). In total, 73 % of offshore workers reported prolonged fatigue. A significant difference in fatigue scores was found between offshore workers aged <45 and ≥55 years (mean 36.0 vs. 37.6; p = 0.024). Further, a "dip" was reported by 41 % of offshore workers. Dips were mainly experienced at day 10 or 11 (60 %), with 45 % experiencing the dip both as physical and mental fatigue, whereas 39 % experienced the dip as only mental fatigue. Both qualitative and quantitative analyses identified work, food and sleep/fatigue management as most important program objectives for a healthy ageing at work and sustainable employability program offshore. Future studies should investigate possible causes of dip occurrences and high fatigue scores to identify suitable interventions.

Evaluation of strains in bituminous surfaces : stiffness-fatigue investigation.

DOT National Transportation Integrated Search

1973-01-01

The study was designed to determine if strains in Virginia's thin asphaltic pavements were high enough to cause early fatigue failure. Strains were computed with the Chevron multilayer computer program, and also measured on selected highways using el...

Fatigue and Muscle Strength Involving Walking Speed in Parkinson's Disease: Insights for Developing Rehabilitation Strategy for PD.

PubMed

Huang, Ying-Zu; Chang, Fang-Yu; Liu, Wei-Chia; Chuang, Yu-Fen; Chuang, Li-Ling; Chang, Ya-Ju

2017-01-01

Background . Problems with gait in Parkinson's disease (PD) are a challenge in neurorehabilitation, partly because the mechanisms causing the walking disability are unclear. Weakness and fatigue, which may significantly influence gait, are commonly reported by patients with PD. Hence, the aim of this study was to investigate the association between weakness and fatigue and walking ability in patients with PD. Methods . We recruited 25 patients with idiopathic PD and 25 age-matched healthy adults. The maximum voluntary contraction (MVC), twitch force, and voluntary activation levels were measured before and after a knee fatigue exercise. General fatigue, central fatigue, and peripheral fatigue were quantified by exercise-induced changes in MVC, twitch force, and activation level. In addition, subjective fatigue was measured using the Multidimensional Fatigue Inventory (MFI) and Fatigue Severity Scale (FSS). Results . The patients with PD had lower activation levels, more central fatigue, and more subjective fatigue than the healthy controls. There were no significant differences in twitch force or peripheral fatigue index between the two groups. The reduction in walking speed was related to the loss of peripheral strength and PD itself. Conclusion . Fatigue and weakness of central origin were related to PD, while peripheral strength was important for walking ability. The results suggest that rehabilitation programs for PD should focus on improving both central and peripheral components of force.

Cyclic fatigue analysis of rocket thrust chambers. Volume 1: OFHC copper chamber low cycle fatigue

NASA Technical Reports Server (NTRS)

Miller, R. W.

1974-01-01

A three-dimensional finite element elasto-plastic strain analysis was performed for the throat section of a regeneratively cooled rocket combustion chamber. The analysis employed the RETSCP finite element computer program. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the chamber operating cycle. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen combustion chamber which was fatigue tested to failure. The computed strain range at typical chamber operating conditions was used in conjunction with oxygen-free, high-conductivity (OHFC) copper isothermal fatigue test data to predict chamber low-cycle fatigue life.

Prestraining and Its Influence on Subsequent Fatigue Life

NASA Technical Reports Server (NTRS)

Halford, Gary R.; Mcgaw, Michael A.; Kalluri, Sreeramesh

1995-01-01

An experimental program was conducted to study the damaging effects of tensile and compressive prestrains on the fatigue life of nickel-base, Inconel 718 superalloy at room temperature. To establish baseline fatigue behavior, virgin specimens with a solid uniform gage section were fatigued to failure under fully-reversed strain-control. Additional specimens were prestrained to 2 percent, 5 percent, and 10 percent (engineering strains) in the tensile direction and to 2 percent (engineering strain) in the compressive direction under stroke-control, and were subsequently fatigued to failure under fully-reversed strain-control. Experimental results are compared with estimates of remaining fatigue lives (after prestraining) using three life prediction approaches: (1) the Linear Damage Rule; (2) the Linear Strain and Life Fraction Rule; and (3) the nonlinear Damage Curve Approach. The Smith-Watson-Topper parameter was used to estimate fatigue lives in the presence of mean stresses. Among the cumulative damage rules investigated, best remaining fatigue life predictions were obtained with the nonlinear Damage Curve Approach.

The relationships among health promotion behaviors, compassion fatigue, burnout, and compassion satisfaction in nurses practicing in a community medical center.

PubMed

Neville, Kathleen; Cole, Donna A

2013-06-01

The objective of this study was to examine the relationships among health promotion behaviors, compassion fatigue, burnout, and compassion satisfaction among nurses practicing in a community medical center. Compassion fatigue and burnout are significant nursing stressors. Programs are available to offset the negative consequence of compassion fatigue and burnout and enhance compassion satisfaction, yet there remains a paucity of literature examining the relationships between health promotion behaviors, compassion fatigue, burnout, and compassion satisfaction. A nonexperimental design using a convenience sample of nurses completed the Health Promoting Lifestyle Profile II, the Professional Quality of Life Scale, and a demographic data sheet. Statistically significant relationships among health promotional behaviors and compassion fatigue, compassion satisfaction, and burnout were identified. Compassion fatigue, burnout, and compassion satisfaction are outcomes associated with nursing practice. Support for engagement in health promotional behaviors may contribute to nurses' well-being in counteracting compassion fatigue and burnout and enhancing compassion satisfaction.

Force Management Methods. Task 1 Report. Current Methods

DTIC Science & Technology

1978-12-01

information about the F/FB-III MCR system is presented in USAF T.O. IF-IlIA-2-1-2 ("F-Ill Service Usage Recorder Program -- Data Collection and Reporting ...34) and T.O. 1F-Ill(B) -2-1-2 ("FB-III Service Usage Program -- Data Collection and Reporting "). The former covers application of the MCR system in F-IIIA...Control Program" NOR 71 -109 "Structural Description Report " NOR 71 -214 "Structural Fatigue Criteria" NOR 76-70 "Structural Fatigue Criteria for Saudi

Microprogrammable Integrated Data Acquisition System-Fatigue Life Data Application

DTIC Science & Technology

1976-03-01

Lt. James W. Sturges, successfully applied the Midas general system [Sturges, 1975] to the fatigue life data monitoring problem and proved its...life data problem . The Midas FLD system computer program generates the required signals in the proper sequence for effectively sampling the 8-channel...Integrated Data Acquisition System- Fatigue Life Data Application" ( Midas FLD) is a microprocessor based data acquisition system. It incorporates a Pro-Log

Research on the Effects of Fatigue within the Corporate/Business Aircraft Environment

NASA Technical Reports Server (NTRS)

Neri, David F.; Rosekind, Mark R.; Co, Elizabeth L.; Gregory, Kevin B.; Miller, Donna L.

1997-01-01

In 1980, responding to a Congressional request, NASA Ames Research Center created a program to examine whether 'there is a safety problem of uncertain magnitude, due to transmeridian flying and a potential problem due to fatigue in association with various factors found in air transport operations.' The NASA Ames Fatigue/Jet Lag Program was created to collect systematic, scientific information on fatigue, sleep, circadian rhythms, and performance in flight operations. Three Program goals were established and continue to guide research efforts to: (1) determine the extent of fatigue, sleep loss, and circadian disruption in flight operations; (2) determine the impact of these factors on flight crew performance; (3) develop and evaluate countermeasures to mitigate the adverse effects of these factors and maximize flight crew performance and alertness. Since 1980, studies have been conducted in a variety of aviation environments, in controlled laboratory environments, as well as in a full-mission flight simulation. Early studies included investigations of short-haul, long-haul, and overnight cargo flight crews. In 1991, the name of the program was changed to the Fatigue Countermeasures Program to provide a greater emphasis on the development and evaluation of countermeasures. More recent work has examined the effects of planned cockpit rest as an operational countermeasure and provided analyses of the pertinent sleep/duty factors preceding an aviation accident at Guantanamo Bay, Cuba. The Short-Haul study examined the extent of sleep loss, circadian disruption, and fatigue engendered by flying commercial short-haul air transport operations (flight legs less than eight hours). This was one of the first field studies conducted by the NASA program and provided unique insight into the physiological and subjective effects of flying commercial short-haul operations. It demonstrated that a range of measures could be obtained in an operational environment without disturbing the regular performance of duties. The Long-Haul study examined how long-haul flight crews organized their sleep during a variety of international trip patterns and examined how duty requirements, local time, and the circadian system affected the timing, duration, and quality of sleep. Duty requirements and local time can be viewed as external/environmental constraints on time available for sleep, while the internal circadian system is a major physiological modulator of sleep duration and quality. The Overnight Cargo study documented the psychophysiological effects of flying overnight cargo operations. The data collected clearly demonstrated that overnight cargo operations, like other night work, involve physiological disruption not found in comparable daytime operations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mandell, John F.; Ashwill, Thomas D.; Wilson, Timothy J.

This report presents an analysis of trends in fatigue results from the Montana State University program on the fatigue of composite materials for wind turbine blades for the period 2005-2009. Test data can be found in the SNL/MSU/DOE Fatigue of Composite Materials Database which is updated annually. This is the fifth report in this series, which summarizes progress of the overall program since its inception in 1989. The primary thrust of this program has been research and testing of a broad range of structural laminate materials of interest to blade structures. The report is focused on current types of infusedmore » and prepreg blade materials, either processed in-house or by industry partners. Trends in static and fatigue performance are analyzed for a range of materials, geometries and loading conditions. Materials include: sixteen resins of three general types, five epoxy based paste adhesives, fifteen reinforcing fabrics including three fiber types, three prepregs, many laminate lay-ups and process variations. Significant differences in static and fatigue performance and delamination resistance are quantified for particular materials and process conditions. When blades do fail, the likely cause is fatigue in the structural detail areas or at major flaws. The program is focused strongly on these issues in addition to standard laminates. Structural detail tests allow evaluation of various blade materials options in the context of more realistic representations of blade structure than do the standard test methods. Types of structural details addressed in this report include ply drops used in thickness tapering, and adhesive joints, each tested over a range of fatigue loading conditions. Ply drop studies were in two areas: (1) a combined experimental and finite element study of basic ply drop delamination parameters for glass and carbon prepreg laminates, and (2) the development of a complex structured resin-infused coupon including ply drops, for comparison studies of various resins, fabrics and pry drop thicknesses. Adhesive joint tests using typical blade adhesives included both generic testing of materials parameters using a notched-lap-shear test geometry developed in this study, and also a series of simulated blade web joint geometries fabricated by an industry partner.« less

Education and Training Module in Alertness Management

NASA Technical Reports Server (NTRS)

Mallis, M. M.; Brandt, S. L.; Oyung, R. L.; Reduta, D. D.; Rosekind, M. R.

2006-01-01

The education and training module (ETM) in alertness management has now been integrated as part of the training regimen of the Pilot Proficiency Awards Program ("WINGS") of the Federal Aviation Administration. Originated and now maintained current by the Fatigue Countermeasures Group at NASA Ames Research Center, the ETM in Alertness Management is designed to give pilots the benefit of the best and most recent research on the basics of sleep physiology, the causes of fatigue, and strategies for managing alertness during flight operations. The WINGS program is an incentive program that encourages pilots at all licensing levels to participate in recurrent training, upon completion of which distinctive lapel or tie pins (wings) and certificates of completion are awarded. In addition to flight training, all WINGS applicants must attend at least one FAA-sponsored safety seminar, FAA-sanctioned safety seminar, or industry recurrent training program. The Fatigue Countermeasures Group provides an FAA-approved industry recurrent training program through an on-line General Aviation (GA) WINGS ETM in alertness management to satisfy this requirement. Since 1993, the Fatigue Countermeasures Group has translated fatigue and alertness information to operational environments by conducting two-day ETM workshops oriented primarily toward air-carrier operations subject to Part 121 of the Federal Aviation Regulations pertaining to such operations. On the basis of the information presented in the two-day ETM workshops, an ETM was created for GA pilots and was transferred to a Web-based version. To comply with the requirements of the WINGS Program, the original Web-based version has been modified to include hypertext markup language (HTML) content that makes information easily accessible, in-depth testing of alertness-management knowledge, new interactive features, and increased informational resources for GA pilots. Upon successful completion of this training module, a participant receives a computer- screen display of a certificate of completion. The certificate, which includes the pilot s name and an identifying number, can be printed out and submitted, for ground training credit, with the pilot s WINGS application.

Effects of Different Exercise Modalities on Fatigue in Prostate Cancer Patients Undergoing Androgen Deprivation Therapy: A Year-long Randomised Controlled Trial.

PubMed

Taaffe, Dennis R; Newton, Robert U; Spry, Nigel; Joseph, David; Chambers, Suzanne K; Gardiner, Robert A; Wall, Brad A; Cormie, Prue; Bolam, Kate A; Galvão, Daniel A

2017-08-01

Physical exercise mitigates fatigue during androgen deprivation therapy (ADT); however, the effects of different exercise prescriptions are unknown. To determine the long-term effects of different exercise modes on fatigue in prostate cancer patients undergoing ADT. Between 2009 and 2012, 163 prostate cancer patients aged 43-90 y on ADT were randomised to exercise targeting the musculoskeletal system (impact loading+resistance training; ILRT; n=58), the cardiovascular and muscular systems (aerobic+resistance training; ART; n=54), or to usual care/delayed exercise (DEL; n=51) for 12 mo across university-affiliated exercise clinics in Australia. Supervised ILRT for 12 mo, supervised ART for 6 mo followed by a 6-mo home program, and DEL received a printed booklet on exercise information for 6 mo followed by 6-mo stationary cycling exercise. Fatigue was assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 36 and vitality using the Short Form-36. Analysis of variance was used to compare outcomes for groups at 6 mo and 12 mo. Fatigue was reduced (p=0.005) in ILRT at 6 mo and 12 mo (∼5 points), and in ART (p=0.005) and DEL (p=0.022) at 12 mo. Similarly, vitality increased for all groups (p≤0.001) at 12 mo (∼4 points). Those with the highest levels of fatigue and lowest vitality improved the most with exercise (p trend <0.001). A limitation was inclusion of mostly well-functioning individuals. Different exercise modes have comparable effects on reducing fatigue and enhancing vitality during ADT. Patients with the highest levels of fatigue and lowest vitality had the greatest benefits. We compared the effects of different exercise modes on fatigue in men on androgen deprivation therapy. All exercise programs reduced fatigue and enhanced vitality. We conclude that undertaking some form of exercise will help reduce fatigue, especially in those who are the most fatigued. Copyright © 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Postural orthostatic tachycardia syndrome: Dental treatment considerations.

PubMed

Brooks, John K; Francis, Laurie A P

2006-04-01

Postural orthostatic tachycardia syndrome (POTS) is a chronic, relatively common autonomic disorder typically affecting younger females. It is distinguished by a dramatic increase in heart rate on the assumption of an upright posture from the supine position. The authors provide an overview of the demographics, clinical assessment, diagnostic features, differential diagnoses, pathogeneses and medical treatment of patients with POTS, with an emphasis on the clinical treatment of the dental patient affected by the syndrome. Patients frequently exhibit symptoms of lightheadedness, fatigue, palpitations and syncope. Patients with POTS may have Ehlers-Danlos syndrome, mitral valve prolapse, chronic fatigue syndrome or, rarely, the Brugada syndrome. Despite widespread dissemination of information regarding POTS in the medical literature, scant information on it has appeared in dental publications. Dentists need to be familiar with the clinical features of POTS and be prepared to treat patients at risk of developing syncope.

Long-Acting Antiretrovirals: Where Are We now?

PubMed

Nyaku, Amesika N; Kelly, Sean G; Taiwo, Babafemi O

2017-04-01

Current HIV treatment options require daily use of combination antiretroviral drugs. Many persons living with HIV experience treatment fatigue and suboptimal adherence as a result. Long-acting antiretroviral drugs are being developed to expand options for HIV treatment. Here, we review the agents in development, and evaluate data from recent clinical trials. In addition, we anticipate challenges to successful widespread use of long-acting antiretrovirals. Parenteral nanosuspensions of cabotegravir and rilpivirine, and dapivirine vaginal ring are the farthest in clinical development. Long-acting modalities in earlier development stages employ drug-loaded implants, microparticles, or targeted mutagenesis, among other innovations. Long-acting antiretroviral drugs promise new options for HIV prevention and treatment, and ways to address poor adherence and treatment fatigue. Further studies will identify the long-acting agents or combinations that are suitable for routine use. Creative solutions will be needed for anticipated implementation challenges.

A meta-analysis to determine the effect of pharmacological and non-pharmacological treatments on fibromyalgia symptoms comprising OMERACT-10 response criteria.

PubMed

Papadopoulou, Despoina; Fassoulaki, Argyro; Tsoulas, Christos; Siafaka, Ioanna; Vadalouca, Athina

2016-03-01

Fibromyalgia is characterized by widespread pain, sleep problems, fatigue, functional impairment, psychological distress, and cognitive dysfunction. The objective of this meta-analysis is to synthesize the available data on the effectiveness of pharmacological and non-pharmacological interventions across all domains included in the Outcome Measures in Rheumatology Clinical Trials (OMERACT-10) fibromyalgia response definitions, and to examine response based on these definitions. We searched Cochrane, PubMed, Scopus, and the reference lists of articles for randomized controlled trials of any drug formulation or non-pharmacological intervention used for fibromyalgia treatment. We extracted efficacy data regarding pain, sleep, physical function, fatigue, anxiety, depression, and cognition. The available data were insufficient to draw definite conclusions regarding response. Indirect evidence indicates that it may be expected with the use of serotonin noradrenaline reuptake inhibitors (SNRIs), noradrenaline reuptake inhibitors (NRIs), and multidisciplinary treatment.

[24-hour work: the interaction of stress and changes in the sleep-wake cycle in the police force].

PubMed

Garbarino, Sergio

2014-01-01

Disruption in police officers. In recent years there has been a widespread growth in services, available regardless of time or day organization (24/7 service) and a diffuse increase in their use, both in work and private lives, generally ignoring the importance of a regular sleep organization. Police officers - often need to work extended shifts and long hours under highly stressful conditions, which results in reduced levels of safety and operational effectiveness. In numerous studies, perceived stress has been found to correlate with both subjective and objective disturbances in sleep. Consequently, excessive daytime sleepiness is one of the most frequent health and safety hazards that police officers have to deal with. Sleep deprivation affects performance outcomes through a wide range of cognitive domains. Sleepiness and fatigue, caused by sleep loss, extended work and wakefulness, circadian misalignment and sleep disorders are major causes of workplace human errors, incidents, and accidents. Therefore, prevention of sleep loss, high levels of stress and fatigue is a key factor to consider when assessing emergency intervention. In order to combat fatigue and sleepiness, a 30-90 minutes nap before night shift could be a viable option.

Pediatric fibromyalgia.

PubMed

Buskila, Dan

2009-05-01

Fibromyalgia is an idiopathic chronic pain syndrome defined by widespread nonarticular musculoskeletal pain and generalized tender points. The syndrome is associated with a constellation of symptoms, including fatigue, nonrefreshing sleep, irritable bowel, and more. Central nervous system sensitization is a major pathophysiologic aspect of fibromyalgia; in addition, various external stimuli such as trauma and stress may contribute to development of the syndrome. Fibromyalgia is most common in midlife, but may be seen at any age. This article reviews the epidemiology, clinical characteristics, etiology, management, and outcome of pediatric fibromyalgia.

Fibromyalgia: clinical features, diagnosis and management.

PubMed

Walker, Jennie

2016-09-28

Patients with fibromyalgia experience chronic widespread pain, with associated symptoms of fatigue, sleep disturbance and memory problems. There are many therapies which may be helpful in managing the symptoms of fibromyalgia; however, these often require a process of trial and error to establish optimum management using a combination of pharmacological and non-pharmacological approaches. Nurses can support patients with fibromyalgia using a biopsychosocial approach to symptom management. Understanding the nature of fibromyalgia and management options will enable nurses to deliver holistic patient-centred care.

Evaluation of tilting disc valves after fatigue life testing: preliminary results within a comparison program.

PubMed

Barbaro, V; Boccanera, G; Daniele, C; Grigioni, M; Palombo, A

1995-09-01

A fatigue life test, by accelerating the beat rate, simulates several years of virtual life of a prosthetic heart valve in a short period of time. The correlation between the in vivo life of a valve and in vitro testing expectations is as yet not well established, but reproducible test conditions yield precious information about wear and failure. The paper reports a qualitative analysis of mechanical valve wear as part of a comparison program designed to investigate the significance of fatigue testing with the ultimate aim of defining standard guidelines for these type of tests. Two tilting disc valves (29 mm) were subjected to 16 years of fatigue life simulated by means of a Rowan Ash fatigue tester (accelerated rate of 1,200 bpm). Fatigue-induced effects on valve disc and ring surfaces were observed under a monitor microscope to identify wear sites and patterns. A high speed cinematographic system was used to investigate the mechanisms responsible for the wear (wear modes). Valve closure was inspected at a 6,000 frame/s rate. Because of disc rotation during the tilting movement, the points of contact between disc and ring are distributed all around the disc edge but focally on the ring. On both sides of the disc, the surfaces present ring-like concentric grooves. After 16 years of fatigue life the valves showed neither severe wear nor alteration of their fluidodynamic behavior in the pulsatile flow test.

Life prediction and constitutive models for engine hot section anisotropic materials program

NASA Technical Reports Server (NTRS)

Nissley, D. M.; Meyer, T. G.

1992-01-01

This report presents the results from a 35 month period of a program designed to develop generic constitutive and life prediction approaches and models for nickel-based single crystal gas turbine airfoils. The program is composed of a base program and an optional program. The base program addresses the high temperature coated single crystal regime above the airfoil root platform. The optional program investigates the low temperature uncoated single crystal regime below the airfoil root platform including the notched conditions of the airfoil attachment. Both base and option programs involve experimental and analytical efforts. Results from uniaxial constitutive and fatigue life experiments of coated and uncoated PWA 1480 single crystal material form the basis for the analytical modeling effort. Four single crystal primary orientations were used in the experiments: (001), (011), (111), and (213). Specific secondary orientations were also selected for the notched experiments in the optional program. Constitutive models for an overlay coating and PWA 1480 single crystal material were developed based on isothermal hysteresis loop data and verified using thermomechanical (TMF) hysteresis loop data. A fatigue life approach and life models were selected for TMF crack initiation of coated PWA 1480. An initial life model used to correlate smooth and notched fatigue data obtained in the option program shows promise. Computer software incorporating the overlay coating and PWA 1480 constitutive models was developed.

Fatigue Crack Growth Threshold Testing of Metallic Rotorcraft Materials

NASA Technical Reports Server (NTRS)

Newman, John A.; James, Mark A.; Johnson, William M.; Le, Dy D.

2008-01-01

Results are presented for a program to determine the near-threshold fatigue crack growth behavior appropriate for metallic rotorcraft alloys. Four alloys, all commonly used in the manufacture of rotorcraft, were selected for study: Aluminum alloy 7050, 4340 steel, AZ91E Magnesium, and Titanium alloy Ti-6Al-4V (beta-STOA). The Federal Aviation Administration (FAA) sponsored this research to advance efforts to incorporate damage tolerance design and analysis as requirements for rotorcraft certification. Rotorcraft components are subjected to high cycle fatigue and are typically subjected to higher stresses and more stress cycles per flight hour than fixed-wing aircraft components. Fatigue lives of rotorcraft components are generally spent initiating small fatigue cracks that propagate slowly under near-threshold cracktip loading conditions. For these components, the fatigue life is very sensitive to the near-threshold characteristics of the material.

Fatigue and fail-safe design features of the DC-10 airplane

NASA Technical Reports Server (NTRS)

Stone, M. E.

1972-01-01

The philosophy and methods used in the design of the DC-10 aircraft to assure structural reliability against cracks under repeated service loads are described in detail. The approach consists of three complementary parts: (1) the structure is designed to be fatigue resistant for a crack-free life of 60,000 flight hours; (2) inasmuch as small undetected cracks could develop from other sources, such as material flaws and manufacturing preloads, the structure also is designed to arrest and control cracks within a reasonable service-inspection interval; and (3) a meaningful service-inspection program has been defined on the basis of analysis and test experience from the design development program. This service-inspection program closes the loop to assure the structural integrity of the DC-10 airframe. Selected materials, fasteners, and structural arrangements are used to achieve these design features with minimum structural weight and with economy in manufacturing and maintenance. Extensive analyses and testing were performed to develop and verify the design. The basic design considerations for fatigue-resistant structure are illustrated in terms of material selection, design loads spectra, methods for accurate stress and fatigue damage analysis, and proven concepts for efficient detail design.

Stress and fatigue effects of driving longer combination vehicles

DOT National Transportation Integrated Search

2000-07-01

This Tech Brief summarizes the final report of a study by the same title, which was conducted as a part of a major program by the Federal Highway Administration to investigate commercial driver fatigue in commercial motor vehicle (CMV) operations. Th...

Eye-activity measures of fatigue and napping as a fatigue countermeasure : tech brief.

DOT National Transportation Integrated Search

2011-08-01

This report presents the test plan for collecting and analyzing safety data for the Atlanta Congestion Reduction Demonstration (CRD) under the United States Department of Transportation (U.S. DOT) Urban Partnership Agreement (UPA) and CRD Programs. T...

Pediatric novice nurses: examining compassion fatigue as a mediator between stress exposure and compassion satisfaction, burnout, and job satisfaction.

PubMed

Meyer, Rika M L; Li, Angela; Klaristenfeld, Jessica; Gold, Jeffrey I

2015-01-01

We investigated whether compassion fatigue mediated associations between nurse stress exposure and job satisfaction, compassion satisfaction, and burnout, controlling for pre-existing stress. The Life Events Checklist was administered to 251 novice pediatric nurses at the start of the nurse residency program (baseline) and 3 months after to assess pre-existing and current stress exposure. Compassion satisfaction, compassion fatigue, and burnout were assessed 3 months after baseline and job satisfaction 6 months after. Stress exposure significantly predicted lower compassion satisfaction and more burnout. Compassion fatigue partially mediated these associations. Results demonstrate a need for hospitals to prevent compassion fatigue in healthcare providers. Copyright © 2015 Elsevier Inc. All rights reserved.

Fatigue crack growth model RANDOM2 user manual. Appendix 1: Development of advanced methodologies for probabilistic constitutive relationships of material strength models

NASA Technical Reports Server (NTRS)

Boyce, Lola; Lovelace, Thomas B.

1989-01-01

FORTRAN program RANDOM2 is presented in the form of a user's manual. RANDOM2 is based on fracture mechanics using a probabilistic fatigue crack growth model. It predicts the random lifetime of an engine component to reach a given crack size. Details of the theoretical background, input data instructions, and a sample problem illustrating the use of the program are included.

The effect of six weeks endurance training on dynamic muscular control of the knee following fatiguing exercise.

PubMed

Hassanlouei, H; Falla, D; Arendt-Nielsen, L; Kersting, U G

2014-10-01

The aim of the study was to examine whether six weeks of endurance training minimizes the effects of fatigue on postural control during dynamic postural perturbations. Eighteen healthy volunteers were assigned to either a 6-week progressive endurance training program on a cycle ergometer or a control group. At week 0 and 7, dynamic exercise was performed on an ergometer until exhaustion and immediately after, the anterior-posterior centre of pressure (COP) sway was analyzed during full body perturbations. Maximal voluntary contractions (MVC) of the knee flexors and extensors, muscle fiber conduction velocity (MFCV) of the vastus lateralis and medialis during sustained isometric knee extension contractions, and power output were measured. Following the training protocol, maximum knee extensor and flexor force and power output increased significantly for the training group with no changes observed for the control group. Moreover, the reduction of MFCV due to fatigue changed for the training group only (from 8.6% to 3.4%). At baseline, the fatiguing exercise induced an increase in the centre of pressure sway during the perturbations in both groups (>10%). The fatiguing protocol also impaired postural control in the control group when measured at week 7. However, for the training group, sway was not altered after the fatiguing exercise when assessed at week 7. In summary, six weeks of endurance training delayed the onset of muscle fatigue and improved the ability to control balance in response to postural perturbations in the presence of muscle fatigue. Results implicate that endurance training should be included in any injury prevention program. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electrically-induced muscle fatigue affects feedforward mechanisms of control.

PubMed

Monjo, F; Forestier, N

2015-08-01

To investigate the effects of focal muscle fatigue induced by electromyostimulation (EMS) on Anticipatory Postural Adjustments (APAs) during arm flexions performed at maximal velocity. Fifteen healthy subjects performed self-paced arm flexions at maximal velocity before and after the completion of fatiguing electromyostimulation programs involving the medial and anterior deltoids and aiming to degrade movement peak acceleration. APA timing and magnitude were measured using surface electromyography. Following muscle fatigue, despite a lower mechanical disturbance evidenced by significant decreased peak accelerations (-12%, p<.001), APAs remained unchanged as compared to control trials (p>.11 for all analyses). The fatigue signals evoked by externally-generated contractions seem to be gated by the Central Nervous System and result in postural strategy changes which aim to increase the postural safety margin. EMS is widely used in rehabilitation and training programs for its neuromuscular function-related benefits. However and from a motor control viewpoint, the present results show that the use of EMS can lead to acute inaccuracies in predictive motor control. We propose that clinicians should investigate the chronic and global effects of EMS on motor control. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Probabilistic material strength degradation model for Inconel 718 components subjected to high temperature, high-cycle and low-cycle mechanical fatigue, creep and thermal fatigue effects

NASA Technical Reports Server (NTRS)

Bast, Callie C.; Boyce, Lola

1995-01-01

This report presents the results of both the fifth and sixth year effort of a research program conducted for NASA-LeRC by The University of Texas at San Antonio (UTSA). The research included on-going development of methodology for a probabilistic material strength degradation model. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes five effects that typically reduce lifetime strength: high temperature, high-cycle mechanical fatigue, low-cycle mechanical fatigue, creep and thermal fatigue. Statistical analysis was conducted on experimental Inconel 718 data obtained from the open literature. This analysis provided regression parameters for use as the model's empirical material constants, thus calibrating the model specifically for Inconel 718. Model calibration was carried out for five variables, namely, high temperature, high-cycle and low-cycle mechanical fatigue, creep and thermal fatigue. Methodology to estimate standard deviations of these material constants for input into the probabilistic material strength model was developed. Using an updated version of PROMISS, entitled PROMISS93, a sensitivity study for the combined effects of high-cycle mechanical fatigue, creep and thermal fatigue was performed. Then using the current version of PROMISS, entitled PROMISS94, a second sensitivity study including the effect of low-cycle mechanical fatigue, as well as, the three previous effects was performed. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing a combination of high-cycle mechanical fatigue and high temperature effects by model to the combination by experiment were conducted. Thus, for Inconel 718, the basic model assumption of independence between effects was evaluated. Results from this limited verification study strongly supported this assumption.

Fatigue behavior of AAR Class A railroad wheel steel at ambient and elevated temperatures.

DOT National Transportation Integrated Search

2006-12-01

This report documents a test program to determine the material properties (chemical composition, tensile, and fatigue) at ambient and elevated temperatures of a Class A wheel steel as designated by the Association of American Railroads. The 3 tempera...

Effectiveness of core stability exercises and recovery myofascial release massage on fatigue in breast cancer survivors: a randomized controlled clinical trial.

PubMed

Cantarero-Villanueva, Irene; Fernández-Lao, Carolina; Del Moral-Avila, Rosario; Fernández-de-Las-Peñas, César; Feriche-Fernández-Castanys, María Belén; Arroyo-Morales, Manuel

2012-01-01

The purpose of the present paper was to evaluate the effects of an 8-week multimodal program focused on core stability exercises and recovery massage with DVD support for a 6-month period in physical and psychological outcomes in breast cancer survivors. A randomized controlled clinical trial was performed. Seventy-eight (n = 78) breast cancer survivors were assigned to experimental (core stability exercises plus massage-myofascial release) and control (usual health care) groups. The intervention period was 8 weeks. Mood state, fatigue, trunk curl endurance, and leg strength were determined at baseline, after the last treatment session, and at 6 months of followup. Immediately after treatment and at 6 months, fatigue, mood state, trunk curl endurance, and leg strength exhibited greater improvement within the experimental group compared to placebo group. This paper showed that a multimodal program focused on core stability exercises and massage reduced fatigue, tension, depression, and improved vigor and muscle strength after intervention and 6 months after discharge.

Solder creep-fatigue interactions with flexible leaded parts

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.; Wen, L. C.; Mon, G. R.; Jetter, E.

1992-01-01

With flexible leaded parts, the solder-joint failure process involves a complex interplay of creep and fatigue mechanisms. To better understand the role of creep in typical multi-hour cyclic loading conditions, a specialized non-linear finite-element creep simulation computer program has been formulated. The numerical algorithm includes the complete part-lead-solder-PWB system, accounting for strain-rate dependence of creep on applied stress and temperature, and the role of the part-lead dimensions and flexibility that determine the total creep deflection (solder strain range) during stress relaxation. The computer program has been used to explore the effects of various solder creep-fatigue parameters such as lead height and stiffness, thermal-cycle test profile, and part/board differential thermal expansion properties. One of the most interesting findings is the strong presence of unidirectional creep-ratcheting that occurs during thermal cycling due to temperature dominated strain-rate effects. To corroborate the solder fatigue model predictions, a number of carefully controlled thermal-cycle tests have been conducted using special bimetallic test boards.

Gear crack propagation investigations

NASA Technical Reports Server (NTRS)

Lewicki, David G.; Ballarini, Roberto

1996-01-01

Analytical and experimental studies were performed to investigate the effect of gear rim thickness on crack propagation life. The FRANC (FRacture ANalysis Code) computer program was used to simulate crack propagation. The FRANC program used principles of linear elastic fracture mechanics, finite element modeling, and a unique re-meshing scheme to determine crack tip stress distributions, estimate stress intensity factors, and model crack propagation. Various fatigue crack growth models were used to estimate crack propagation life based on the calculated stress intensity factors. Experimental tests were performed in a gear fatigue rig to validate predicted crack propagation results. Test gears were installed with special crack propagation gages in the tooth fillet region to measure bending fatigue crack growth. Good correlation between predicted and measured crack growth was achieved when the fatigue crack closure concept was introduced into the analysis. As the gear rim thickness decreased, the compressive cyclic stress in the gear tooth fillet region increased. This retarded crack growth and increased the number of crack propagation cycles to failure.

The Effects of Low to Moderate Intensity Aerobic Exercise on Fatigue in Breast Cancer Patients Following Clinical Treatment

DTIC Science & Technology

2006-09-01

between the groups (p = .0003) and within the groups (p =. 01). The decrease in depression in the exercise group (89%) neared significance (p = .052...exercise program was effective in improving aerobic capacity, lower-body flexibility, fatigue, depression , anxiety, confusion, anger, and energy in the...Appendix F: 10-week LASA Fatigue Graph Appendix G: 10-week LASA Depression Graph Appendix H: 10-week LASA Anxiety Graph Appendix I: 10-week

Statistical complex fatigue data for SAE 4340 steel and its use in design by reliability

NASA Technical Reports Server (NTRS)

Kececioglu, D.; Smith, J. L.

1970-01-01

A brief description of the complex fatigue machines used in the test program is presented. The data generated from these machines are given and discussed. Two methods of obtaining strength distributions from the data are also discussed. Then follows a discussion of the construction of statistical fatigue diagrams and their use in designing by reliability. Finally, some of the problems encountered in the test equipment and a corrective modification are presented.

Jim Starnes' Contributions to Residual Strength Analysis Methods for Metallic Structures

NASA Technical Reports Server (NTRS)

Young, Richard D.; Rose, Cheryl A.; Harris, Charles E.

2005-01-01

A summary of advances in residual strength analyses methods for metallic structures that were realized under the leadership of Dr. James H. Starnes, Jr., is presented. The majority of research led by Dr. Starnes in this area was conducted in the 1990's under the NASA Airframe Structural Integrity Program (NASIP). Dr. Starnes, respectfully referred to herein as Jim, had a passion for studying complex response phenomena and dedicated a significant amount of research effort toward advancing damage tolerance and residual strength analysis methods for metallic structures. Jim's efforts were focused on understanding damage propagation in built-up fuselage structure with widespread fatigue damage, with the goal of ensuring safety in the aging international commercial transport fleet. Jim's major contributions in this research area were in identifying the effects of combined internal pressure and mechanical loads, and geometric nonlinearity, on the response of built-up structures with damage. Analytical and experimental technical results are presented to demonstrate the breadth and rigor of the research conducted in this technical area. Technical results presented herein are drawn exclusively from papers where Jim was a co-author.

A systems approach to solder joint fatigue in spacecraft electronic packaging

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

1991-01-01

Differential expansion induced fatigue resulting from temperature cycling is a leading cause of solder joint failures in spacecraft. Achieving high reliability flight hardware requires that each element of the fatigue issue be addressed carefully. This includes defining the complete thermal-cycle environment to be experienced by the hardware, developing electronic packaging concepts that are consistent with the defined environments, and validating the completed designs with a thorough qualification and acceptance test program. This paper describes a useful systems approach to solder fatigue based principally on the fundamental log-strain versus log-cycles-to-failure behavior of fatigue. This fundamental behavior has been useful to integrate diverse ground test and flight operational thermal-cycle environments into a unified electronics design approach. Each element of the approach reflects both the mechanism physics that control solder fatigue, as well as the practical realities of the hardware build, test, delivery, and application cycle.

Polarization fatigue of organic ferroelectric capacitors

PubMed Central

Zhao, Dong; Katsouras, Ilias; Li, Mengyuan; Asadi, Kamal; Tsurumi, Junto; Glasser, Gunnar; Takeya, Jun; Blom, Paul W. M.; de Leeuw, Dago M.

2014-01-01

The polarization of the ferroelectric polymer P(VDF-TrFE) decreases upon prolonged cycling. Understanding of this fatigue behavior is of great technological importance for the implementation of P(VDF-TrFE) in random-access memories. However, the origin of fatigue is still ambiguous. Here we investigate fatigue in thin-film capacitors by systematically varying the frequency and amplitude of the driving waveform. We show that the fatigue is due to delamination of the top electrode. The origin is accumulation of gases, expelled from the capacitor, under the impermeable top electrode. The gases are formed by electron-induced phase decomposition of P(VDF-TrFE), similar as reported for inorganic ferroelectric materials. When the gas barrier is removed and the waveform is adapted, a fatigue-free ferroelectric capacitor based on P(VDF-TrFE) is realized. The capacitor can be cycled for more than 108 times, approaching the programming cycle endurance of its inorganic ferroelectric counterparts. PMID:24861542

Empirical modeling of environment-enhanced fatigue crack propagation in structural alloys for component life prediction

NASA Technical Reports Server (NTRS)

Richey, Edward, III

1995-01-01

This research aims to develop the methods and understanding needed to incorporate time and loading variable dependent environmental effects on fatigue crack propagation (FCP) into computerized fatigue life prediction codes such as NASA FLAGRO (NASGRO). In particular, the effect of loading frequency on FCP rates in alpha + beta titanium alloys exposed to an aqueous chloride solution is investigated. The approach couples empirical modeling of environmental FCP with corrosion fatigue experiments. Three different computer models have been developed and incorporated in the DOS executable program. UVAFAS. A multiple power law model is available, and can fit a set of fatigue data to a multiple power law equation. A model has also been developed which implements the Wei and Landes linear superposition model, as well as an interpolative model which can be utilized to interpolate trends in fatigue behavior based on changes in loading characteristics (stress ratio, frequency, and hold times).

Compassion fatigue and burnout: what managers should know.

PubMed

Slatten, Lise Anne; David Carson, Kerry; Carson, Paula Phillips

2011-01-01

Most health care employees experience and are bolstered by compassion satisfaction as they deal with patients in need. However, the more empathetic a health care provider is, the more likely he or she will experience compassion fatigue. Compassion fatigue is a negative syndrome that occurs when dealing with the traumatic experiences of patients, and examples of symptoms include intrusive thoughts, sleeping problems, and depression. Compassion fatigue is different from burnout. Compassion fatigue is a rapidly occurring disorder for primary health care workers who work with suffering patients, whereas burnout, a larger construct, is a slowly progressing disorder for employees who typically are working in burdensome organizational environments. Managers can mitigate problems associated with compassion fatigue with a number of interventions including patient reassignments, formal mentoring programs, employee training, and a compassionate organizational culture. With burnout, health care managers will want to focus primarily on chronic organizational problems.

Feasibility and changes in symptoms and functioning following inpatient cancer rehabilitation.

PubMed

Bertheussen, Gro F; Kaasa, Stein; Hokstad, Anne; Sandmæl, Jon Arne; Helbostad, Jorunn L; Salvesen, Øyvind; Oldervoll, Line M

2012-11-01

The aim was to assess feasibility of a 3 + 1 week inpatient rehabilitation program for cancer survivors, to explore characteristics of the attending participants and examine changes in work status, symptoms and functioning, level of fatigue, exercise and physical performance following rehabilitation. This was an open intervention study involving cancer survivors having completed primary cancer treatment. The multidisiplinary program consisted of physical training, patient education and group sessions. Participant were assessed at primary stay (T0), at follow-up stay 8-12 weeks later (T1), and six months after T1 (T2). Symptoms and functioning were assessed by the European Organization for Research and Treatment Core Quality-of-Life Questionnaire, physical fatigue by Fatigue Questionnaire, physical exercise by The Nord- Trøndelag Health Study Physical Activity Questionnaire and physical performance by aerobic capacity (VO(2max)), 30 second Sit-to-stand (STS) and Maximum Step Length (MSL). Linear mixed models were used in analyses. One hundred and thirty-four of 163 included participants (82%) completed both rehabilitation stays and returned questionaires at T2. The majority of completers were females (81%), breast cancer survivors (60%), highly educated and with mean age of 52.8 years (SD of 8.1). Participants had higher level of symptoms and fatigue and lower functioning at admission compared to a Norwegian reference population. However, they reported higher physical exercise level and 47% reported improved work status from T0 to T2. Symptoms and functioning, fatigue, physical exercise and physical performance improved significantly from T0 to T1 and were maintained at T2. The rehabilitation program was feasible and symptoms and functioning normalized following rehabilitation. The program mainly recruited well-educated breast cancer survivors, reporting relative high level of physical exercise. More focus should be put on recruiting and selecting those who need comprehensive inpatient rehabilitation and also compare the effects of inpatient with outpatient rehabilitation programs.

The prevalence of fibromyalgia and its relation with headache characteristics in episodic migraine.

PubMed

Küçükşen, Sami; Genç, Emine; Yılmaz, Halim; Sallı, Ali; Gezer, İlknur Albayrak; Karahan, Ali Yavuz; Salbaş, Ender; Cingöz, Havva Turaç; Nas, Ömer; Uğurlu, Hatice

2013-07-01

The objective of this study was to assess the prevalence of fibromyalgia (FM) in patients with episodic migraine and to evaluate the relationship between migraine characteristics and FM. One hundred and eighteen consecutive patients (mean age = 38 years, 75% women) fulfilling the International Classification of Headache Disorders-II criteria for migraine with (n = 22) and without (n = 96) aura from an outpatient headache clinic of a university hospital were evaluated. The diagnosis of FM was made based on the 1990 American College of Rheumatology classification criteria. Participants completed some self-administered questionnaires ascertaining sociodemographics, headache severity, frequency and duration, headache-related disability (Headache Impact Test [HIT-6]) and Migraine Disability Assessment Scale, widespread musculoskeletal pain (visual analog scale), depression (Beck depression inventory), anxiety (Beck anxiety inventory), sleep quality (Pittsburgh Sleep Quality Index), fatigue (Multidimensional Assessment of Fatigue), and quality of life (Short Form-36 Health Survey [SF-36]). In patients with FM, the tender point count and the Fibromyalgia Impact Questionnaire were employed. FM was diagnosed in 37 (31.4%) of the patients. FM comorbidity was equally distributed across patients with and without aura. Severity of migraine headache, HIT-6, and anxiety were especially associated with FM comorbidity. Patients suffering from migraine plus FM reported lower scores on all items of the SF-36. This study indicates that the assessment and management of coexisting FM should be taken into account in the assessment and management of migraine, particularly when headache is severe or patients suffer from widespread musculoskeletal pain.

Thermal fatigue and thermal shock in bedrock: An attempt to unravel the geomorphic processes and products

NASA Astrophysics Data System (ADS)

Hall, Kevin; Thorn, Colin E.

2014-02-01

Widespread acceptance in science at-large notwithstanding, the ability of thermal stresses to produce thermal fatigue (TF) and/or thermal shock (TS) in bedrock and coarse debris in the field is often doubted. Commonly called insolation weathering in geomorphology, the results of questionable laboratory experiments have led many geomorphologists to consider terrestrial temperatures to be inadequate to generate thermally induced stresses leading to rock failure; the exceptions are the action of fire or lightning. We comprehensively survey the general scientific literature on TF and TS while rigorously scrutinizing that relating to geomorphology. Findings indicate theoretical and experimental information is adequate to establish the feasibility of TF and TS in rock stemming from rock temperatures monitored in the field. While TS may exhibit fracture patterns that are uniquely diagnostic, those of TF lack any such attributes. It would appear unlikely that TF can prepare or weaken rock to increase the likelihood of TS. The question of whether widespread polygonal versus rectilinear cracking is diagnostic of TS is presently an open one as possible explanations invoke process(es) and/or host material(s) and, consequently, to assign palaeoenvironmental significance to such fracture patterns is premature at this time. Further geomorphological laboratory research into TF and TS is merited as sufficient theoretical underpinning already exists. However, laboratory experimentation needs to be much more rigorously defined and executed and is faced with significant hurdles if it is to be effectively linked to field observations.

Fatigue behavior of railcar wheel steel at ambient and elevated temperature

DOT National Transportation Integrated Search

2003-08-01

This report presents the results of a material property test program undertaken on a Class B railcar wheel steel. This work was performed to obtain relevant fatigue data that may be used in support of a larger effort exploring the applicability of fa...

Evaluation of a functional medicine approach to treating fatigue, stress, and digestive issues in women.

PubMed

Cutshall, Susanne M; Bergstrom, Larry R; Kalish, Daniel J

2016-05-01

Fatigue, stress, and digestive disorders are common among adults, especially women. We conducted a 28-week pilot study to assess the efficacy of a functional medicine approach to improving stress, energy, fatigue, digestive issues, and quality of life in middle-aged women. Findings showed significant improvements in many stress, fatigue, and quality-of-life measures. The treatment program increased mean salivary dehydroepiandrosterone levels and the cortisol-dehydroepiandrosterone ratio. Stool sample analyses suggested that these treatments reduced Helicobacter pylori infections. This study suggests that functional medicine may be an effective approach to managing stress and gastrointestinal symptoms. Copyright © 2016 Elsevier Ltd. All rights reserved.

Efficacy of a Home-Based Exercise Program After Thyroidectomy for Thyroid Cancer Patients.

PubMed

Kim, Kyunghee; Gu, Mee Ock; Jung, Jung Hwa; Hahm, Jong Ryeal; Kim, Soo Kyoung; Kim, Jin Hyun; Woo, Seung Hoon

2018-02-01

The objective of this study was to determine the effect of a home-based exercise program on fatigue, anxiety, quality of life (QoL), and immune function of thyroid cancer patients taking thyroid hormone replacement after thyroidectomy. This quasi-experimental study with a non-equivalent control group included 43 outpatients taking thyroid hormone replacement after thyroidectomy (22 in the experimental group and 21 in the control group). After education about the home-based exercise program, subjects in the experimental group underwent 12 weeks of aerobic, resistance, and flexibility exercise. A comparative analysis was conducted between the two groups. Patients in the experimental group were significantly less fatigued or anxious (p < 0.01). They reported significantly improved QoL (p < 0.05) compared to those in the control group. Natural killer cell activity was significantly higher in the exercise group compared to that in the control group (p < 0.05). A home-based exercise program is effective in reducing fatigue and anxiety, improving QoL, and increasing immune function in patients taking thyroid hormone replacement after thyroidectomy. Therefore, such a home-based exercise program can be used as an intervention for patients who are taking thyroid hormone replacement after thyroidectomy.

Design of the Physical exercise during Adjuvant Chemotherapy Effectiveness Study (PACES): a randomized controlled trial to evaluate effectiveness and cost-effectiveness of physical exercise in improving physical fitness and reducing fatigue.

PubMed

van Waart, Hanna; Stuiver, Martijn M; van Harten, Wim H; Sonke, Gabe S; Aaronson, Neil K

2010-12-07

Cancer chemotherapy is frequently associated with a decline in general physical condition, exercise tolerance, and muscle strength and with an increase in fatigue. While accumulating evidence suggests that physical activity and exercise interventions during chemotherapy treatment may contribute to maintaining cardiorespiratory fitness and strength, the results of studies conducted to date have not been consistent. Additional research is needed to determine the optimal intensity of exercise training programs in general and in particular the relative effectiveness of supervised, outpatient (hospital- or physical therapy practice-based) versus home-based programs. This multicenter, prospective, randomized trial will evaluate the effectiveness of a low to moderate intensity, home-based, self-management physical activity program, and a high intensity, structured, supervised exercise program, in maintaining or enhancing physical fitness (cardiorespiratory fitness and muscle strength), in minimizing fatigue and in enhancing the health-related quality of life (HRQoL). Patients receiving adjuvant chemotherapy for breast or colon cancer (n = 360) are being recruited from twelve hospitals in the Netherlands, and randomly allocated to one of the two treatment groups or to a 'usual care' control group. Performance-based and self-reported outcomes are assessed at baseline, at the end of chemotherapy and at six month follow-up. This large, multicenter, randomized clinical trial will provide additional empirical evidence regarding the effectiveness of physical exercise during adjuvant chemotherapy in enhancing physical fitness, minimizing fatigue, and maintaining or enhancing patients' quality of life. If demonstrated to be effective, exercise intervention programs will be a welcome addition to the standard program of care offered to patients with cancer receiving chemotherapy. This study is registered at the Netherlands Trial Register (NTR 2159).

Life prediction and constitutive models for engine hot section anisotropic materials program

NASA Technical Reports Server (NTRS)

Nissley, D. M.; Meyer, T. G.; Walker, K. P.

1992-01-01

This report presents a summary of results from a 7 year program designed to develop generic constitutive and life prediction approaches and models for nickel-based single crystal gas turbine airfoils. The program was composed of a base program and an optional program. The base program addressed the high temperature coated single crystal regime above the airfoil root platform. The optional program investigated the low temperature uncoated single crystal regime below the airfoil root platform including the notched conditions of the airfoil attachment. Both base and option programs involved experimental and analytical efforts. Results from uniaxial constitutive and fatigue life experiments of coated and uncoated PWA 1480 single crystal material formed the basis for the analytical modeling effort. Four single crystal primary orientations were used in the experiments: group of zone axes (001), group of zone axes (011), group of zone axes (111), and group of zone axes (213). Specific secondary orientations were also selected for the notched experiments in the optional program. Constitutive models for an overlay coating and PWA 1480 single crystal materials were developed based on isothermal hysteresis loop data and verified using thermomechanical (TMF) hysteresis loop data. A fatigue life approach and life models were developed for TMF crack initiation of coated PWA 1480. A life model was developed for smooth and notched fatigue in the option program. Finally, computer software incorporating the overlay coating and PWA 1480 constitutive and life models was developed.

Feasibility, Validity, and Reliability of the Italian Pediatric Quality of Life Inventory Multidimensional Fatigue Scale for Adults in Inpatients with Severe Obesity

PubMed Central

Manzoni, Gian Mauro; Rossi, Alessandro; Marazzi, Nicoletta; Agosti, Fiorenza; De Col, Alessandra; Pietrabissa, Giada; Castelnuovo, Gianluca; Molinari, Enrico; Sartorio, Allessandro

2018-01-01

Objective This study was aimed to examine the feasibility, validity, and reliability of the Italian Pediatric Quality of Life Inventory Multidimensional Fatigue Scale (PedsQL™ MFS) for adult inpatients with severe obesity. Methods 200 inpatients (81% females) with severe obesity (BMI ≥ 35 kg/m2) completed the PedsQL MFS (General Fatigue, Sleep/Rest Fatigue and Cognitive Fatigue domains), the Fatigue Severity Scale, and the Center for Epidemiologic Studies Depression Scale immediately after admission to a 3-week residential body weight reduction program. A randomized subsample of 48 patients re-completed the PedsQL MFS after 3 days. Results Confirmatory factor analysis showed that a modified hierarchical model with two items moved from the Sleep/Rest Fatigue domain to the General Fatigue domain and a second-order latent factor best fitted the data. Internal consistency and test-retest reliabilities were acceptable to high in all scales, and small to high statistically significant correlations were found with all convergent measures, with the exception of BMI. Significant floor effects were found in two scales (Cognitive Fatigue and Sleep/Rest Fatigue). Conclusion The Italian modified PedsQL MFS for adults showed to be a valid and reliable tool for the assessment of fatigue in inpatients with severe obesity. Future studies should assess its discriminant validity as well as its responsiveness to weight reduction. PMID:29402854

Natural Fatigue Crack Initiation and Detection in High Quality Spur Gears

DTIC Science & Technology

2012-06-01

Natural Fatigue Crack Initiation and Detection in High Quality Spur Gears by David “Blake” Stringer, Ph.D., Kelsen E. LaBerge, Ph.D., Cory...0383 June 2012 Natural Fatigue Crack Initiation and Detection in High Quality Spur Gears David “Blake” Stringer and Ph.D., Kelsen E. LaBerge...Quality Spur Gears 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) David “Blake” Stringer, Ph.D., Kelsen E

Development of composite carrythrough bulkhead

NASA Technical Reports Server (NTRS)

Ehlen, R. J.; Libeskind, M.

1992-01-01

A structural development program was recently completed in which the weight and fatigue advantages of an all composite major load carrying bulkhead was successfully demonstrated. Fabrication of a full scale article, including static and fatigue testing of the carry-through beam portion verified the producibility, strength and durability of this design, thereby presenting the opportunity for use on aircraft upgrades and new aircraft. A 15% weight saving is achievable and, more importantly, the fatigue problems that normally plague metal bulkheads are virtually eliminated.

An investigation of strain cycling behavior of 7075-T6 aluminum under combined state of strain: The effects of out-of-phase, biaxial strain cycling on low cycle fatigue

NASA Technical Reports Server (NTRS)

Zamrik, S. Y.

1972-01-01

The effect of out-of-phase strain cycling on the low cycle fatigue of biaxially loaded specimens is discussed. A method to apply phase angles between two strains imposed in two different directions was developed. The data and the proposed theoretical analysis are part of a research program on biaxial strain cycling effect on fatigue life of structural materials.

Fatigue-Crack-Growth Structural Analysis

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.

1986-01-01

Elastic and plastic deformations calculated under variety of loading conditions. Prediction of fatigue-crack-growth lives made with FatigueCrack-Growth Structural Analysis (FASTRAN) computer program. As cyclic loads are applied to initial crack configuration, FASTRAN predicts crack length and other parameters until complete break occurs. Loads are tensile or compressive and of variable or constant amplitude. FASTRAN incorporates linear-elastic fracture mechanics with modifications of load-interaction effects caused by crack closure. FASTRAN considered research tool, because of lengthy calculation times. FASTRAN written in FORTRAN IV for batch execution.

A Review of Australian and New Zealand Investigations on Aeronautical Fatigue During the Period April 2005 to March 2007

DTIC Science & Technology

2007-04-01

possessed better fatigue properties than the 2024T3 series alloys . It was also possible to develop a fracture mechanic approach which could match...Mechanical Properties of 7050-T7451 Aluminium Alloy . (J.Calero, DSTO) - Paper to be presented at ICAF 2007 Symposium Abstract “It is not uncommon...conductivity, strength, fatigue life and fracture toughness properties of 7050- T7451 aluminium alloy . The test program investigated temperatures ranging

Effect of Stress Ratio on Fatigue Crack Growth Rate at Notched Hole in 7075-T6 Aluminum Alloy Under Biaxial Fatigue

DTIC Science & Technology

2016-08-18

Taylor and Lee studied the effect of in-plane stress biaxility on the fatigue life [22]. Research in this subject is going on but no research done to...closer picture to the hole, notch, pre -crack and the crack in one of the specimens in Abaqus program...which is the scope of this research , using fracture mechanics approach. 6 To achieve the purpose of this study , the specimen has to be test

Fatigue in operational settings: Examples from the aviation environment

NASA Technical Reports Server (NTRS)

Rosekind, Mark R.; Gander, Philippa H.; Miller, Donna L.; Gregory, Kevin B.; Smith, Roy M.; Weldon, Keri J.; Co, Elizabeth L.; Mcnally, Karen L.; Lebacqz, J. Victor

1994-01-01

The need for 24-h operations creates nonstandard and altered work schedules that can lead to cumulative sleep loss and circadian disruption. These factors can lead to fatigue and sleepiness and affect performance and productivity on the job. The approach, research, and results of the NASA Ames Fatigue Countermeasures Program are described to illustrate one attempt to address these issues in the aviation environment. The scientific and operational relevance of these factors is discussed, and provocative issues for future research are presented.

Fatigue flaw growth and NDI evaluation for preventing through cracks in spacecraft tankage structures

NASA Technical Reports Server (NTRS)

Pettit, D. E.; Hoeppner, D. W.

1972-01-01

A program was conducted to determine the fatigue-crack propagation behavior of parent and welded 2219-T87 aluminum alloy sheet under controlled cyclic stress conditions in room temperature air and 300 F air. Specimens possessing an initial surface defect of controlled dimensions were cycled under constant load amplitude until the propagating fatigue crack penetrated the back surface of the specimen. A series of precracked specimens were prepared to determine optimum penetrant, X-ray, ultrasonic, and eddy current nondestructive inspection procedures.

Environmental Effect on Evolutionary Cyclic Plasticity Material Parameters of 316 Stainless Steel: An Experimental & Material Modeling Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohanty, Subhasish; Soppet, William K.; Majumdar, Saurin

2014-09-20

This report provides an update on an earlier assessment of environmentally assisted fatigue for light water reactor (LWR) materials under extended service conditions. This report is a deliverable under the work package for environmentally assisted fatigue in the Light Water Reactor Sustainability (LWRS) program. The overall objective of this LWRS project is to assess the degradation by environmentally assisted cracking/fatigue of LWR materials such as various alloy base metals and their welds used in reactor coolant system piping. This effort is to support the Department of Energy LWRS program for developing tools to understand the aging/failure mechanism and to predictmore » the remaining life of LWR components for anticipated 60-80 year operation.« less

Fatigue crack growth equations for TC-128B tank car steel

DOT National Transportation Integrated Search

2006-10-01

In an effort to develop relevant data for use in applying damage tolerance analysis concepts to railroad tank cars, the fatigue crack growth (FCG) behavior of TC-128B tank car steel was investigated by SwRI in a previous test program conducted for th...

10 CFR 26.203 - General provisions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false General provisions. 26.203 Section 26.203 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Managing Fatigue § 26.203 General provisions. (a) Policy. Licensees shall establish a policy for the management of fatigue for all individuals who are subject to the...

10 CFR 26.203 - General provisions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false General provisions. 26.203 Section 26.203 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Managing Fatigue § 26.203 General provisions. (a) Policy. Licensees shall establish a policy for the management of fatigue for all individuals who are subject to the...

Factors associated with intern fatigue.

PubMed

Friesen, Lindsay D; Vidyarthi, Arpana R; Baron, Robert B; Katz, Patricia P

2008-12-01

Prior data suggest that fatigue adversely affects patient safety and resident well-being. ACGME duty hour limitations were intended, in part, to reduce resident fatigue, but the factors that affect intern fatigue are unknown. To identify factors associated with intern fatigue following implementation of duty hour limitations. Cross-sectional confidential survey of validated questions related to fatigue, sleep, and stress, as well as author-developed teamwork questions. Interns in cognitive specialties at the University of California, San Francisco. Univariate statistics characterized the distribution of responses. Pearson correlations elucidated bivariate relationships between fatigue and other variables. Multivariate linear regression models identified factors independently associated with fatigue, sleep, and stress. Of 111 eligible interns, 66 responded (59%). In a regression analysis including gender, hours worked in the previous week, sleep quality, perceived stress, and teamwork, only poorer quality of sleep and greater perceived stress were significantly associated with fatigue (p < 0.001 and p = 0.02, respectively). To identify factors that may affect sleep, specifically duty hours and stress, a secondary model was constructed. Only greater perceived stress was significantly associated with diminished sleep quality (p = 0.04), and only poorer teamwork was significantly associated with perceived stress (p < 0.001). Working >80 h was not significantly associated with perceived stress, quality of sleep, or fatigue. Simply decreasing the number of duty hours may be insufficient to reduce intern fatigue. Residency programs may need to incorporate programmatic changes to reduce stress, improve sleep quality, and foster teamwork in order to decrease intern fatigue and its deleterious consequences.

Fatigue life estimation program for Part 23 airplanes, `AFS.FOR`

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaul, S.K.

1993-12-31

The purpose of this paper is to introduce to the general aviation industry a computer program which estimates the safe fatigue life of any Federal Aviation Regulation (FAR) Part 23 airplane. The algorithm uses the methodology (Miner`s Linear Cumulative Damage Theory) and the various data presented in the Federal Aviation Administration (FAA) Report No. AFS-120-73-2, dated May 1973. The program is written in FORTRAN 77 language and is executable on a desk top personal computer. The program prompts the user for the input data needed and provides a variety of options for its intended use. The program is envisaged tomore » be released through issuance of a FAA report, which will contain the appropriate comments, instructions, warnings and limitations.« less

Disk Alloy Development

NASA Technical Reports Server (NTRS)

Gabb, Tim; Gayda, John; Telesman, Jack

2001-01-01

The advanced powder metallurgy disk alloy ME3 was designed using statistical screening and optimization of composition and processing variables in the NASA HSR/EPM disk program to have extended durability at 1150 to 1250 "Fin large disks. Scaled-up disks of this alloy were produced at the conclusion of this program to demonstrate these properties in realistic disk shapes. The objective of the UEET disk program was to assess the mechanical properties of these ME3 disks as functions of temperature, in order to estimate the maximum temperature capabilities of this advanced alloy. Scaled-up disks processed in the HSR/EPM Compressor / Turbine Disk program were sectioned, machined into specimens, and tested in tensile, creep, fatigue, and fatigue crack growth tests by NASA Glenn Research Center, in cooperation with General Electric Engine Company and Pratt & Whitney Aircraft Engines. Additional sub-scale disks and blanks were processed and tested to explore the effects of several processing variations on mechanical properties. Scaled-up disks of an advanced regional disk alloy, Alloy 10, were used to evaluate dual microstructure heat treatments. This allowed demonstration of an improved balance of properties in disks with higher strength and fatigue resistance in the bores and higher creep and dwell fatigue crack growth resistance in the rims. Results indicate the baseline ME3 alloy and process has 1300 to 1350 O F temperature capabilities, dependent on detailed disk and engine design property requirements. Chemistry and process enhancements show promise for further increasing temperature capabilities.

Stretching and Joint Mobilization Exercises Reduce Call-Center Operators’ Musculoskeletal Discomfort and Fatigue

PubMed Central

de Castro Lacaze, Denise Helena; Sacco, Isabel de C. N.; Rocha, Lys Esther; de Bragança Pereira, Carlos Alberto; Casarotto, Raquel Aparecida

2010-01-01

AIM: We sought to evaluate musculoskeletal discomfort and mental and physical fatigue in the call-center workers of an airline company before and after a supervised exercise program compared with rest breaks during the work shift. INTRODUCTION: This was a longitudinal pilot study conducted in a flight-booking call-center for an airline in São Paulo, Brazil. Occupational health activities are recommended to decrease the negative effects of the call-center working conditions. In practice, exercise programs are commonly recommended for computer workers, but their effects have not been studied in call-center operators. METHODS: Sixty-four call-center operators participated in this study. Thirty-two subjects were placed into the experimental group and attended a 10-min daily exercise session for 2 months. Conversely, 32 participants were placed into the control group and took a 10-min daily rest break during the same period. Each subject was evaluated once a week by means of the Corlett-Bishop body map with a visual analog discomfort scale and the Chalder fatigue questionnaire. RESULTS: Musculoskeletal discomfort decreased in both groups, but the reduction was only statistically significant for the spine and buttocks (p=0.04) and the sum of the segments (p=0.01) in the experimental group. In addition, the experimental group showed significant differences in the level of mental fatigue, especially in questions related to memory Rienzo, #181ff and tiredness (p=0.001). CONCLUSIONS: Our preliminary results demonstrate that appropriately designed and supervised exercise programs may be more efficient than rest breaks in decreasing discomfort and fatigue levels in call-center operators. PMID:20668622

An interventional approach for patient and nurse safety: a fatigue countermeasures feasibility study.

PubMed

Scott, Linda D; Hofmeister, Nancee; Rogness, Neal; Rogers, Ann E

2010-01-01

Studies indicate that extended shifts worked by hospital staff nurses are associated with higher risk of errors. Long work hours coupled with insufficient sleep and fatigue are even riskier. Although other industries have developed programs to reduce fatigue-related errors and injury, fatigue countermeasures program for nurses (FCMPN) are lacking. The objective of this study was to evaluate the feasibility of an FCMPN for improving sleep duration and quality while reducing daytime sleepiness and patient care errors. Selected sleep variables, errors and drowsy driving, were evaluated among hospital staff nurses (n = 47) before and after FCMPN implementation. A one-group pretest-posttest repeated-measures approach was used. Participants provided data 2 weeks before the FCMPN, 4 weeks after receiving the intervention, and again at 3 months after intervention. Most of the nurses experienced poor sleep quality, severe daytime sleepiness, and decreased alertness at work and while operating a motor vehicle. After the FCMPN, significant improvements were noted in sleep duration, sleep quality, alertness, and error prevention. Although significant improvements were not found in daytime sleepiness scores, severity of daytime sleepiness appeared to decrease. Despite improvements in fatigue management, nurses reported feelings of guilt when engaging in FCMPN activities, especially strategic naps and relieved breaks. Initial findings support the feasibility of using an FCMPN for mitigating fatigue, improving sleep, and reducing errors among hospital staff nurses. In future investigations, the acceptability, efficacy, and effectiveness of FCMPNs can be examined.

Elevated temperature biaxial fatigue

NASA Technical Reports Server (NTRS)

Jordan, E. H.

1985-01-01

A 3 year experimental program for studying elevated temperature biaxial fatigue of a nickel based alloy Hastelloy-X has been completed. A new high temperature fatigue test facility with unique capabilities has been developed. Effort was directed toward understanding multiaxial fatigue and correlating the experimental data to the existing theories of fatigue failure. The difficult task of predicting fatigue lives for nonproportional loading was used as an ultimate test for various life prediction methods being considered. The primary means of reaching improved understanding were through several critical nonproportional loading experiments. The direction of cracking observed on failed specimens was also recorded and used to guide the development of the theory. Cyclic deformation responses were permanently recorded digitally during each test. It was discovered that the cracking mode switched from primarily cracking on the maximum shear planes at room temperature to cracking on the maximum normal strain planes at 649 C. In contrast to some other metals, loading path in nonproportional loading had little effect on fatigue lives. Strain rate had a small effect on fatigue lives at 649 C. Of the various correlating parameters the modified plastic work and octahedral shear stress were the most successful.

Compassion fatigue among pediatric healthcare providers.

PubMed

Branch, Carole; Klinkenberg, Dean

2015-01-01

Compassion fatigue is a term used to describe the unique stressors affecting people in caregiving professions. For nurses and other direct care providers, the impact of compassion fatigue may result in stress-related symptoms, job dissatisfaction, decreased productivity, decreased patient satisfaction scores, safety issues, and job turnover. Those who care for seriously ill children and their families are at increased risk for compassion fatigue. Constant exposure to children who are suffering, in combination with work place stressors and personal issues, may contribute to the development of compassion fatigue. The Professional Quality of Life Scale Version 5 was used to determine the risk for compassion fatigue among 296 direct care providers at St. Louis Children's Hospital. Compassion satisfaction, burnout, and secondary traumatic stress scores did not differ by age, work category, level of education, or work experience. There were, however, significant differences in scores as a function of nursing unit. Nurses who work in the pediatric intensive care unit reported lower compassion satisfaction scores, and higher burnout and secondary traumatic stress scores. Results demonstrated the risk for compassion fatigue and provided data necessary to support development of a compassion fatigue program for direct care providers.

Behavioral pattern identification for structural health monitoring in complex systems

NASA Astrophysics Data System (ADS)

Gupta, Shalabh

Estimation of structural damage and quantification of structural integrity are critical for safe and reliable operation of human-engineered complex systems, such as electromechanical, thermofluid, and petrochemical systems. Damage due to fatigue crack is one of the most commonly encountered sources of structural degradation in mechanical systems. Early detection of fatigue damage is essential because the resulting structural degradation could potentially cause catastrophic failures, leading to loss of expensive equipment and human life. Therefore, for reliable operation and enhanced availability, it is necessary to develop capabilities for prognosis and estimation of impending failures, such as the onset of wide-spread fatigue crack damage in mechanical structures. This dissertation presents information-based online sensing of fatigue damage using the analytical tools of symbolic time series analysis ( STSA). Anomaly detection using STSA is a pattern recognition method that has been recently developed based upon a fixed-structure, fixed-order Markov chain. The analysis procedure is built upon the principles of Symbolic Dynamics, Information Theory and Statistical Pattern Recognition. The dissertation demonstrates real-time fatigue damage monitoring based on time series data of ultrasonic signals. Statistical pattern changes are measured using STSA to monitor the evolution of fatigue damage. Real-time anomaly detection is presented as a solution to the forward (analysis) problem and the inverse (synthesis) problem. (1) the forward problem - The primary objective of the forward problem is identification of the statistical changes in the time series data of ultrasonic signals due to gradual evolution of fatigue damage. (2) the inverse problem - The objective of the inverse problem is to infer the anomalies from the observed time series data in real time based on the statistical information generated during the forward problem. A computer-controlled special-purpose fatigue test apparatus, equipped with multiple sensing devices (e.g., ultrasonics and optical microscope) for damage analysis, has been used to experimentally validate the STSA method for early detection of anomalous behavior. The sensor information is integrated with a software module consisting of the STSA algorithm for real-time monitoring of fatigue damage. Experiments have been conducted under different loading conditions on specimens constructed from the ductile aluminium alloy 7075 - T6. The dissertation has also investigated the application of the STSA method for early detection of anomalies in other engineering disciplines. Two primary applications include combustion instability in a generic thermal pulse combustor model and whirling phenomenon in a typical misaligned shaft.

Damage tolerance of bonded composite aircraft repairs for metallic structures

NASA Astrophysics Data System (ADS)

Clark, Randal John

This thesis describes the development and validation of methods for damage tolerance substantiation of bonded composite repairs applied to cracked plates. This technology is used to repair metal aircraft structures, offering improvements in fatigue life, cost, manufacturability, and inspectability when compared to riveted repairs. The work focuses on the effects of plate thickness and bending on repair life, and covers fundamental aspects of fracture and fatigue of cracked plates and bonded joints. This project falls under the UBC Bonded Composite Repair Program, which has the goal of certification and widespread use of bonded repairs in civilian air transportation. This thesis analyses the plate thickness and transverse stress effects on fracture of repaired plates and the related problem of induced geometrically nonlinear bending in unbalanced (single-sided) repairs. The author begins by developing a classification scheme for assigning repair damage tolerance substantiation requirements based upon stress-based adhesive fracture/fatigue criteria and the residual strength of the original structure. The governing equations for bending of cracked plates are then reformulated and line-spring models are developed for linear and nonlinear coupled bending and extension of reinforced cracks. The line-spring models were used to correct the Wang and Rose energy method for the determination of the long-crack limit stress intensity, and to develop a new interpolation model for repaired cracks of arbitrary length. The analysis was validated using finite element models and data from mechanical tests performed on hybrid bonded joints and repair specimens that are representative of an in-service repair. This work will allow designers to evaluate the damage tolerance of the repaired plate, the adhesive, and the composite patch, which is an airworthiness requirement under FAR (Federal Aviation Regulations) 25.571. The thesis concludes by assessing the remaining barriers to certification of bonded repairs, discussing the results of the analysis, and making suggestions for future work. The developed techniques should also prove to be useful for the analysis of fibre-reinforced metal laminates and other layered structures. Some concepts are general and should be useful in the analysis of any plate with large in-plane stress gradients that lead to significant transverse stresses.

Elevated Temperature Fatigue Endurance of Three Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Kalluri, Sreeramesh; Verrilli, Michael J.

2007-01-01

High-cycle fatigue endurance of three candidate materials for the acoustic liners of the Enabling Propulsion Materials Nozzle Program was investigated. The ceramic matrix composite materials investigated were N720/AS (Nextel 720, 3M Corporation), Sylramic S200 (Dow Corning), and UT 22. High-cycle fatigue tests were conducted in air at 910 C on as-machined specimens and on specimens subjected to tensile cyclic load excursions every 160 hr followed by thermal exposure at 910 C in a furnace up to total exposure times of 2066 and 4000 hr. All the fatigue tests were conducted in air at 100 Hz with a servohydraulic test machine. In the as-machined condition, among the three materials investigated only the Sylramic S200 exhibited a deterministic type of high-cycle fatigue behavior. Both the N720/AS and UT-22 exhibited significant scatter in the experimentally observed high-cycle fatigue lives. Among the thermally exposed specimens, N720/AS and Sylramic S200 materials exhibited a reduction in the high-cycle fatigue lives, particularly at the exposure time of 4000 hr.

Fatigue life prediction modeling for turbine hot section materials

NASA Technical Reports Server (NTRS)

Halford, G. R.; Meyer, T. G.; Nelson, R. S.; Nissley, D. M.; Swanson, G. A.

1989-01-01

A major objective of the fatigue and fracture efforts under the NASA Hot Section Technology (HOST) program was to significantly improve the analytic life prediction tools used by the aeronautical gas turbine engine industry. This was achieved in the areas of high-temperature thermal and mechanical fatigue of bare and coated high-temperature superalloys. The cyclic crack initiation and propagation resistance of nominally isotropic polycrystalline and highly anisotropic single crystal alloys were addressed. Life prediction modeling efforts were devoted to creep-fatigue interaction, oxidation, coatings interactions, multiaxiality of stress-strain states, mean stress effects, cumulative damage, and thermomechanical fatigue. The fatigue crack initiation life models developed to date include the Cyclic Damage Accumulation (CDA) and the Total Strain Version of Strainrange Partitioning (TS-SRP) for nominally isotropic materials, and the Tensile Hysteretic Energy Model for anisotropic superalloys. A fatigue model is being developed based upon the concepts of Path-Independent Integrals (PII) for describing cyclic crack growth under complex nonlinear response at the crack tip due to thermomechanical loading conditions. A micromechanistic oxidation crack extension model was derived. The models are described and discussed.

Fatigue life prediction modeling for turbine hot section materials

NASA Technical Reports Server (NTRS)

Halford, G. R.; Meyer, T. G.; Nelson, R. S.; Nissley, D. M.; Swanson, G. A.

1988-01-01

A major objective of the fatigue and fracture efforts under the Hot Section Technology (HOST) program was to significantly improve the analytic life prediction tools used by the aeronautical gas turbine engine industry. This was achieved in the areas of high-temperature thermal and mechanical fatigue of bare and coated high-temperature superalloys. The cyclic crack initiation and propagation resistance of nominally isotropic polycrystalline and highly anisotropic single crystal alloys were addressed. Life prediction modeling efforts were devoted to creep-fatigue interaction, oxidation, coatings interactions, multiaxiality of stress-strain states, mean stress effects, cumulative damage, and thermomechanical fatigue. The fatigue crack initiation life models developed to date include the Cyclic Damage Accumulation (CDA) and the Total Strain Version of Strainrange Partitioning (TS-SRP) for nominally isotropic materials, and the Tensile Hysteretic Energy Model for anisotropic superalloys. A fatigue model is being developed based upon the concepts of Path-Independent Integrals (PII) for describing cyclic crack growth under complex nonlinear response at the crack tip due to thermomechanical loading conditions. A micromechanistic oxidation crack extension model was derived. The models are described and discussed.

Fatigue and durability of Nitinol stents.

PubMed

Pelton, A R; Schroeder, V; Mitchell, M R; Gong, Xiao-Yan; Barney, M; Robertson, S W

2008-04-01

Nitinol self-expanding stents are effective in treating peripheral artery disease, including the superficial femoral, carotid, and renal arteries. However, fracture occurrences of up to 50% have been reported in some stents after one year. These stent fractures are likely due to in vivo cyclic displacements. As such, the cyclic fatigue and durability properties of Nitinol-based endovascular stents are discussed in terms of an engineering-based experimental testing program. In this paper, the combined effects of cardiac pulsatile fatigue and stent-vessel oversizing are evaluated for application to both stents and stent subcomponents. In particular, displacement-controlled fatigue tests were performed on stent-like specimens processed from Nitinol microtubing. Fatigue data were collected with combinations of simulated oversizing conditions and pulsatile cycles that were identified by computer modeling of the stent that mimic in vivo deformation conditions. These data are analyzed with non-linear finite element computations and are illustrated with strain-life and strain-based constant-life diagrams. The utility of this approach is demonstrated in conjunction with 10 million cycle pulsatile fatigue tests of Cordis SMART Control((R)) Nitinol self-expanding stents to calculate fatigue safety factors and thereby predict in vivo fatigue resistance. These results demonstrate the non-linear constant fatigue-life response of Nitinol stents, whereby, contrary to conventional engineering materials, the fatigue life of Nitinol is observed to increase with increasing mean strain.

The effect of gender and fatigue on the biomechanics of bilateral landings from a jump: peak values.

PubMed

Pappas, Evangelos; Sheikhzadeh, Ali; Hagins, Marshall; Nordin, Margareta

2007-01-01

Female athletes are substantially more susceptible than males to suffer acute non-contact anterior cruciate ligament injury. A limited number of studies have identified possible biomechanical risk factors that differ between genders. The effect of fatigue on the biomechanics of landing has also been inadequately investigated. The objective of the study was to examine the effect of gender and fatigue on peak values of biomechanical variables during landing from a jump. Thirty-two recreational athletes performed bilateral drop jump landings from a 40 cm platform. Kinetic, kinematic and electromyographic data were collected before and after a functional fatigue protocol. Females landed with 9° greater peak knee valgus (p = 0.001) and 140% greater maximum vertical ground reaction forces (p = 0.003) normalized to body weight compared to males. Fatigue increased peak foot abduction by 1.7° (p = 0.042), peak rectus femoris activity by 27% (p = 0.018), and peak vertical ground reaction force (p = 0.038) by 20%. The results of the study suggest that landing with increased peak knee valgus and vertical ground reaction force may contribute to increased risk for knee injury in females. Fatigue caused significant but small changes on some biomechanical variables. Anterior cruciate ligament injury prevention programs should focus on implementing strategies to effectively teach females to control knee valgus and ground reaction force. Key pointsFemale athletes landed with increased knee valgus and VGRF which may predispose them to ACL injury.Fatigue elicited a similar response in male and female athletes.The effectiveness of sports injury prevention programs may improve by focusing on teaching females to land softer and with less knee valgus.

The Effect of Gender and Fatigue on the Biomechanics of Bilateral Landings from a Jump: Peak Values

PubMed Central

Pappas, Evangelos; Sheikhzadeh, Ali; Hagins, Marshall; Nordin, Margareta

2007-01-01

Female athletes are substantially more susceptible than males to suffer acute non-contact anterior cruciate ligament injury. A limited number of studies have identified possible biomechanical risk factors that differ between genders. The effect of fatigue on the biomechanics of landing has also been inadequately investigated. The objective of the study was to examine the effect of gender and fatigue on peak values of biomechanical variables during landing from a jump. Thirty-two recreational athletes performed bilateral drop jump landings from a 40 cm platform. Kinetic, kinematic and electromyographic data were collected before and after a functional fatigue protocol. Females landed with 9° greater peak knee valgus (p = 0.001) and 140% greater maximum vertical ground reaction forces (p = 0.003) normalized to body weight compared to males. Fatigue increased peak foot abduction by 1.7° (p = 0.042), peak rectus femoris activity by 27% (p = 0.018), and peak vertical ground reaction force (p = 0.038) by 20%. The results of the study suggest that landing with increased peak knee valgus and vertical ground reaction force may contribute to increased risk for knee injury in females. Fatigue caused significant but small changes on some biomechanical variables. Anterior cruciate ligament injury prevention programs should focus on implementing strategies to effectively teach females to control knee valgus and ground reaction force. Key pointsFemale athletes landed with increased knee valgus and VGRF which may predispose them to ACL injury.Fatigue elicited a similar response in male and female athletes.The effectiveness of sports injury prevention programs may improve by focusing on teaching females to land softer and with less knee valgus. PMID:24149228

Feasibility, Validity, and Reliability of the Italian Pediatric Quality of Life Inventory Multidimensional Fatigue Scale for Adults in Inpatients with Severe Obesity.

PubMed

Manzoni, Gian Mauro; Rossi, Alessandro; Marazzi, Nicoletta; Agosti, Fiorenza; De Col, Alessandra; Pietrabissa, Giada; Castelnuovo, Gianluca; Molinari, Enrico; Sartorio, Allessandro

2018-01-01

This study was aimed to examine the feasibility, validity, and reliability of the Italian Pediatric Quality of Life Inventory Multidimensional Fatigue Scale (PedsQL™ MFS) for adult inpatients with severe obesity. 200 inpatients (81% females) with severe obesity (BMI ≥ 35 kg/m2) completed the PedsQL MFS (General Fatigue, Sleep/Rest Fatigue and Cognitive Fatigue domains), the Fatigue Severity Scale, and the Center for Epidemiologic Studies Depression Scale immediately after admission to a 3-week residential body weight reduction program. A randomized subsample of 48 patients re-completed the PedsQL MFS after 3 days. Confirmatory factor analysis showed that a modified hierarchical model with two items moved from the Sleep/Rest Fatigue domain to the General Fatigue domain and a second-order latent factor best fitted the data. Internal consistency and test-retest reliabilities were acceptable to high in all scales, and small to high statistically significant correlations were found with all convergent measures, with the exception of BMI. Significant floor effects were found in two scales (Cognitive Fatigue and Sleep/Rest Fatigue). The Italian modified PedsQL MFS for adults showed to be a valid and reliable tool for the assessment of fatigue in inpatients with severe obesity. Future studies should assess its discriminant validity as well as its responsiveness to weight reduction. © 2018 The Author(s) Published by S. Karger GmbH, Freiburg.

[Effects of self-foot reflexology on stress, fatigue, skin temperature and immune response in female undergraduate students].

PubMed

Lee, Young-Mee

2011-02-01

The purpose of this study was to evaluate the effects of self-foot reflexology on stress (perceived stress, urine cortisol level, and serum cortisol level), fatigue, skin temperature and immune response in female undergraduate students. The research design was a nonequivalent control group pretest-post test design. Participants were 60 university students: 30 in the experiment group and 30 in the control group. The period of this study was from April to June 2010. The program was performed for 1 hr a session, three times a week for 6 weeks. The data were analyzed using the SPSS/WIN 17.0 program. The results showed that self-foot reflexology was effective in reducing perceived stress and fatigue, and raised skin temperature in female undergraduate students. But cortisol levels and immune response were not statistically significant different. The results of this study indicate that self-foot reflexology is an effective nursing intervention in reducing perceived stress and fatigue and, in improving skin temperature. Therefore, it is recommended that this be used in clinical practice as an effective nursing intervention for in female undergraduate students.

The influence of modifications of a fatigue loading history program on fatigue lifetime

NASA Technical Reports Server (NTRS)

Branger, J.

1972-01-01

Rectangular specimens of 7075 and 2014 aluminum alloys with two holes (stress concentration factor of 3.24) have been tested under axial fatigue loading on a six-rod test bed with modifications of the loading program, the surface particulars, and the frequency. The length of the precrack stage was investigated by use of a new crack detector. In most cases the two alloys behaved similarly, with similar life to crack start under the same loading. Some overloads lengthened the life. Truncation by omission of the lowest peak loads should be limited to about 20 percent of the ultimate load. Simplifying counting methods gave misleading results. Very thin surface layers of anodizing, protection by vinyl, dry nitrogen atmosphere, as well as stepwise reaming or grinding the surface of the holes, lengthened the life; thick anodized layers shortened the life. Compressing the hole surface by rolling had no influence. Frequencies at about 210 to 240 cpm produced shorter lives than those at 40 cpm. At 5.4 cpm the life was considerably longer. A model to better understand the precrack-stage fatigue mechanism is discussed.

Fatigue strength reduction model: RANDOM3 and RANDOM4 user manual, appendix 2

NASA Technical Reports Server (NTRS)

Boyce, Lola; Lovelace, Thomas B.

1989-01-01

The FORTRAN programs RANDOM3 and RANDOM4 are documented. They are based on fatigue strength reduction, using a probabilistic constitutive model. They predict the random lifetime of an engine component to reach a given fatigue strength. Included in this user manual are details regarding the theoretical backgrounds of RANDOM3 and RANDOM4. Appendix A gives information on the physical quantities, their symbols, FORTRAN names, and both SI and U.S. Customary units. Appendix B and C include photocopies of the actual computer printout corresponding to the sample problems. Appendices D and E detail the IMSL, Version 10(1), subroutines and functions called by RANDOM3 and RANDOM4 and SAS/GRAPH(2) programs that can be used to plot both the probability density functions (p.d.f.) and the cumulative distribution functions (c.d.f.).

Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, High-Cycle and Low-Cycle Mechanical Fatigue, Creep and Thermal Fatigue Effects

NASA Technical Reports Server (NTRS)

Bast, Callie C.; Boyce, Lola

1995-01-01

The development of methodology for a probabilistic material strength degradation is described. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes five effects that typically reduce lifetime strength: high temperature, high-cycle mechanical fatigue, low-cycle mechanical fatigue, creep and thermal fatigue. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing predictions of high-cycle mechanical fatigue and high temperature effects with experiments are presented. Results from this limited verification study strongly supported that material degradation can be represented by randomized multifactor interaction models.

Factors Associated with Intern Fatigue

PubMed Central

Vidyarthi, Arpana R.; Baron, Robert B.; Katz, Patricia P.

2008-01-01

ABSTRACT BACKGROUND Prior data suggest that fatigue adversely affects patient safety and resident well-being. ACGME duty hour limitations were intended, in part, to reduce resident fatigue, but the factors that affect intern fatigue are unknown. OBJECTIVE To identify factors associated with intern fatigue following implementation of duty hour limitations. DESIGN Cross-sectional confidential survey of validated questions related to fatigue, sleep, and stress, as well as author-developed teamwork questions. SUBJECTS Interns in cognitive specialties at the University of California, San Francisco. MEASUREMENTS Univariate statistics characterized the distribution of responses. Pearson correlations elucidated bivariate relationships between fatigue and other variables. Multivariate linear regression models identified factors independently associated with fatigue, sleep, and stress. RESULTS Of 111 eligible interns, 66 responded (59%). In a regression analysis including gender, hours worked in the previous week, sleep quality, perceived stress, and teamwork, only poorer quality of sleep and greater perceived stress were significantly associated with fatigue (p < 0.001 and p = 0.02, respectively). To identify factors that may affect sleep, specifically duty hours and stress, a secondary model was constructed. Only greater perceived stress was significantly associated with diminished sleep quality (p = 0.04), and only poorer teamwork was significantly associated with perceived stress (p < 0.001). Working >80 h was not significantly associated with perceived stress, quality of sleep, or fatigue. CONCLUSIONS Simply decreasing the number of duty hours may be insufficient to reduce intern fatigue. Residency programs may need to incorporate programmatic changes to reduce stress, improve sleep quality, and foster teamwork in order to decrease intern fatigue and its deleterious consequences. PMID:18807096

Fatigue Crack Growth Rate Test Results for Al-Li 2195 Parent Metal, Variable Polarity Plasma Arc Welds and Friction Stir Welds

NASA Technical Reports Server (NTRS)

Hafley, Robert A.; Wagner, John A.; Domack, Marcia S.

2000-01-01

The fatigue crack growth rate of aluminum-lithium (Al-Li) alloy 2195 plate and weldments was determined at 200-F, ambient temperature and -320-F. The effects of stress ratio (R), welding process, orientation and thickness were studied. Results are compared with plate data from the Space Shuttle Super Lightweight Tank (SLWT) allowables program. Data from the current series of tests, both plate and weldment, falls within the range of data generated during the SLWT allowables program.

NDE detectability of fatigue-type cracks in high-strength alloys: NDI reliability assessments

NASA Technical Reports Server (NTRS)

Christner, Brent K.; Long, Donald L.; Rummel, Ward D.

1988-01-01

This program was conducted to generate quantitative flaw detection capability data for the nondestructive evaluation (NDE) techniques typically practiced by aerospace contractors. Inconel 718 and Haynes 188 alloy test specimens containing fatigue flaws with a wide distribution of sizes were used to assess the flaw detection capabilities at a number of contractor and government facilities. During this program 85 inspection sequences were completed presenting a total of 20,994 fatigue cracks to 53 different inspectors. The inspection sequences completed included 78 liquid penetrant, 4 eddy current, and 3 ultrasonic evaluations. The results of the assessment inspections are presented and discussed. In generating the flaw detection capability data base, procedures for data collection, data analysis, and specimen care and maintenance were developed, demonstrated, and validated. The data collection procedures and methods that evolved during this program for the measurement of flaw detection capabilities and the effects of inspection variables on performance are discussed. The Inconel 718 and Haynes 188 test specimens that were used in conducting this program and the NDE assessment procedures that were demonstrated, provide NASA with the capability to accurately assess the flaw detection capabilities of specific inspection procedures being applied or proposed for use on current and future fracture control hardware program.

Three-Dimensional Geometric Nonlinear Contact Stress Analysis of Riveted Joints

NASA Technical Reports Server (NTRS)

Shivakumar, Kunigal N.; Ramanujapuram, Vivek

1998-01-01

The problems associated with fatigue were brought into the forefront of research by the explosive decompression and structural failure of the Aloha Airlines Flight 243 in 1988. The structural failure of this airplane has been attributed to debonding and multiple cracking along the longitudinal lap splice riveted joint in the fuselage. This crash created what may be termed as a minor "Structural Integrity Revolution" in the commercial transport industry. Major steps have been taken by the manufacturers, operators and authorities to improve the structural airworthiness of the aging fleet of airplanes. Notwithstanding, this considerable effort there are still outstanding issues and concerns related to the formulation of Widespread Fatigue Damage which is believed to have been a contributing factor in the probable cause of the Aloha accident. The lesson from this accident was that Multiple-Site Damage (MSD) in "aging" aircraft can lead to extensive aircraft damage. A strong candidate in which MSD is highly probable to occur is the riveted lap joint.

Managing Neuropsychological Impairment in Multiple Sclerosis

PubMed Central

Lau, Stephanie; Penner, Iris; Heesen, Christoph; Moritz, Steffen

2015-01-01

Background: Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease of the central nervous system of potential autoimmune origin that is frequently associated with psychological disorders and cognitive deficits, as well as with fatigue, stress, and psychosocial burden. These factors often cause decreased quality of life, social withdrawal, and unemployment. We describe the development of a cognitive-behavioral group intervention based on the concept of metacognition and evaluation of the feasibility and acceptance of the program as a rehabilitation tool. Methods: Metacognitive Training in MS (MaTiMS) consists of six modules, each 90 minutes in duration. We tested acceptance and design of the program in six focus groups (entire sample, n = 27). Framework analysis of transcripts was used to identify key topics and categories. Program modules were revised in accordance with appropriate recommendations of focus group members. We subsequently evaluated MaTiMS in two groups (n = 5, n = 6) in a rehabilitation center. Neuropsychological functioning as well as coping self-efficacy, depression, stress, perceived cognitive deficit, fatigue, and quality of life were assessed. Acceptance of MaTiMS from the patient perspective was also studied. Results: The modules were highly accepted by patients. Pre-post assessments showed significant improvements in the Coping Self Efficacy Scale (P = .007), the Würzburger Fatigue Inventory for MS Score (P = .028), and the Hamburg Quality of Life Questionnaire in Multiple Sclerosis Mood subscale (P = .046). Conclusions: These preliminary results suggest that MaTiMS represents a feasible psychological group training program that may foster improvements in self-efficacy, fatigue, and mood. The next step will be an evaluation of the program in a randomized controlled trial. PMID:26052258

The effect of yoga exercise on improving depression, anxiety, and fatigue in women with breast cancer: a randomized controlled trial.

PubMed

Taso, Chao-Jung; Lin, Huey-Shyan; Lin, Wen-Li; Chen, Shu-Ming; Huang, Wen-Tsung; Chen, Shang-Wen

2014-09-01

Depression, anxiety, and fatigue are among the most significant problems that influence the quality of life of patients with breast cancer who receive adjuvant chemotherapy. Although evidence has shown yoga to decrease anxiety, depression, and fatigue in patients with cancer, few studies on the effects of yoga have targeted patients with breast cancer. Yoga interventions should be tested to promote the psychological and physical health of women with breast cancer. This study examines the effectiveness of an 8-week yoga exercise program in promoting the psychological and physical health of women with breast cancer undergoing adjuvant chemotherapy in terms of depression, anxiety, and fatigue. A sample of 60 women with nonmetastatic breast cancer was recruited. Participants were randomly assigned into either the experimental group (n = 30) or the control group (n = 30). A 60-minute, twice-per-week yoga exercise was implemented for 8 weeks as the intervention for the participants in the experimental group. The control group received standard care only. Analysis using the Johnson-Neyman procedure found that the yoga exercise reduced overall fatigue and the interference of fatigue in everyday life for the experimental group participants. Significant reductions were obtained after 4 weeks of intervention participation for those experimental group patients with relatively low starting baseline values (baseline item mean value < 3.31 and 3.22, respectively) and after 8 weeks for most patients (approximately 75%) with moderate starting baseline values (baseline item mean value < 7.30 and 5.34, respectively). The 8-week intervention did not significantly improve the levels of depression (F = 1.29, p > .05) or anxiety (F = 2.7, p > .05). The 8-week yoga exercise program developed in this study effectively reduced fatigue in patients with breast cancer but did not reduce depression or anxiety. Oncology nurses should strengthen their clinical health education and apply yoga to reduce the fatigue experienced by patients with breast cancer who undergo adjuvant chemotherapy.

A transient plasticity study and low cycle fatigue analysis of the Space Station Freedom photovoltaic solar array blanket

NASA Technical Reports Server (NTRS)

Armand, Sasan C.; Liao, Mei-Hwa; Morris, Ronald W.

1990-01-01

The Space Station Freedom photovoltaic solar array blanket assembly is comprised of several layers of materials having dissimilar elastic, thermal, and mechanical properties. The operating temperature of the solar array, which ranges from -75 to +60 C, along with the material incompatibility of the blanket assembly components combine to cause an elastic-plastic stress in the weld points of the assembly. The weld points are secondary structures in nature, merely serving as electrical junctions for gathering the current. The thermal mechanical loading of the blanket assembly operating in low earth orbit continually changes throughout each 90 min orbit, which raises the possibility of fatigue induced failure. A series of structural analyses were performed in an attempt to predict the fatigue life of the solar cell in the Space Station Freedom photovoltaic array blanket. A nonlinear elastic-plastic MSC/NASTRAN analysis followed by a fatigue calculation indicated a fatigue life of 92,000 to 160,000 cycles for the solar cell weld tabs. Additional analyses predict a permanent buckling phenomenon in the copper interconnect after the first loading cycle. This should reduce or eliminate the pulling of the copper interconnect on the joint where it is welded to the silicon solar cell. It is concluded that the actual fatigue life of the solar array blanket assembly should be significantly higher than the calculated 92,000 cycles, and thus the program requirement of 87,500 cycles (orbits) will be met. Another important conclusion that can be drawn from the overall analysis is that, the strain results obtained from the MSC/NASTRAN nonlinear module are accurate to use for low-cycle fatigue analysis, since both thermal cycle testing of solar cells and analysis have shown higher fatigue life than the minimum program requirement of 87,500 cycles.

Scapular-Muscle Performance: Two Training Programs in Adolescent Swimmers

PubMed Central

Van de Velde, Annemie; De Mey, Kristof; Maenhout, Annelies; Calders, Patrick; Cools, Ann M.

2011-01-01

Abstract Context: Swimming requires well-balanced scapular-muscle performance. An additional strength-training program for the shoulders is pursued by swimmers, but whether these muscle-training programs need to be generic or specific for endurance or strength is unknown. Objective: To evaluate isokinetic scapular-muscle performance in a population of adolescent swimmers and to compare the results of training programs designed for strength or muscle endurance. Design: Controlled laboratory study. Setting: University human research laboratory. Patients or Other Participants: Eighteen adolescent swimmers. Intervention(s): Each participant pursued a 12-week scapular-training program designed to improve either muscle strength or muscle endurance. Main Outcome Measure(s): Bilateral peak force, fatigue index, and protraction/retraction strength ratios before and after the scapular-training program. Results: Scapular protraction/retraction ratios were slightly higher than 1 (dominant side  =  1.08, nondominant side  =  1.25, P  =  .006). Side-to-side differences in retraction strength were apparent both before and after the training program (P  =  .03 and P  = .05, respectively). After the training program, maximal protraction (P < .05) and retraction (P < .01) strength improved on the nondominant side. Peak force and fatigue index were not different between the training groups. The fatigue indexes for protraction on both sides (P < .05) and retraction on the nondominant side (P  =  .009) were higher after the training program. Conclusions: We describe the scapular-muscle characteristics of a group of adolescent swimmers. Both muscle-strength and muscle-endurance programs improved absolute muscle strength. Neither of the strength programs had a positive effect on scapular-muscle endurance. Our results may be valuable for coaches and physiotherapists when they are designing exercise programs for swimmers. PMID:21391801

Fatigue in the acute care and ambulatory setting.

PubMed

McCabe, Margaret; Patricia, Branowicki

2014-01-01

Nurses commonly assess their patients for symptoms and intervene to ease any patient distress, yet children are seldom asked about feeling fatigued. The existing pediatric literature suggests that fatigue goes unrecognized and therefore untreated in children, particularly children experiencing stressful events, such as illness and/or hospitalization. In an effort to better understand the presence of the symptom in our environment we conducted a program specific point prevalence survey. Data were collected on nine inpatient and 11 outpatient units of a university affiliated tertiary care children's hospital. Overall, this sample reported higher levels of fatigue than published data from their healthy and chronically ill peers by total fatigue score and sub scores. This brief description of the symptom in our inpatient and ambulatory settings has provided information that will inform our nursing practice and drive future research. Copyright © 2014 Elsevier Inc. All rights reserved.

Fatigue of die cast zinc alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schrems, K.K.; Dogan, O.N.; Goodwin, F.E.

2006-04-01

The rotating bending fatigue limit of die cast zinc alloy 2, alloy 3, alloy 5, AcuZinc 5, and ZA-8 were determined as a part of an on-going program by ILZRO into the mechanical properties of die cast zinc. The stress-life (S-N) curves of alloys 3, 5, AcuZinc 5, and ZA-8 were determined previously. This presentation reports the results of the S-N curve for Alloy 2 and the calculated fatigue limits for all five alloys. During the previous stress-life testing, the samples were stopped at 10 million cycles and the fatigue limit for alloy 3, alloy 5, and AcuZinc 5 appearedmore » to be higher and the fatigue limit for ZA-8 appeared to be lower than the values reported in the literature. This was further investigated in alloy 5 and ZA-8 by testing continuous cast bulk alloy 5 and ZA-8.« less

Visual simulation of fatigue crack growth

NASA Astrophysics Data System (ADS)

Wang, Shuanzhu; Margolin, Harold; Lin, Fengbao

1998-07-01

An attempt has been made to visually simulate fatigue crack propagation from a precrack. An integrated program was developed for this purpose. The crack-tip shape was determined at four load positions in the first load cycle. The final shape was a blunt front with an “ear” profile at the precrack tip. A more general model, schematically illustrating the mechanism of fatigue crack growth and striation formation in a ductile material, was proposed based on this simulation. According to the present model, fatigue crack growth is an intermittent process; cyclic plastic shear strain is the driving force applied to both state I and II crack growth. No fracture mode transition occurs between the two stages in the present study. The crack growth direction alternates, moving up and down successively, producing fatigue striations. A brief examination has been made of the crack growth path in a ductile two-phase material.

Assessment of microalloying effects on the high temperature fatigue behavior of NiAl

NASA Technical Reports Server (NTRS)

Noebe, R. D.; Lerch, B. A.; Rao, K. B. S.

1995-01-01

Binary NiAl suffers from a lack of strength and poor creep properties at and above 1000 K. Poor creep resistance in turn affects low cycle fatigue (LCF) lives at low strain ranges due to the additional interactions of creep damage. One approach for improving these properties involved microalloying with either Zr or N. As an integral part of a much larger alloying program the low cycle fatigue behavior of Zr and N doped nickel aluminides produced by extrusion of prealloyed powders has been investigated. Strain controlled LCF tests were performed in air at 1000 K. The influence of these microalloying additions on the fatigue life and cyclic stress response of polycrystalline NiAl are discussed.

Experimental and theoretical investigation of fatigue life in reusable rocket thrust chambers

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Kasper, H. J.; Pavli, A. J.

1976-01-01

During a test program to investigate low-cycle thermal fatigue, 13 rocket combustion chambers were fabricated and cyclically test fired to failure. Six oxygen-free, high-conductivity (OFHC) copper and seven Amzirc chambers were tested. The failures in the OFHC copper chambers were not typical fatigue failures but are described as creep rupture enhanced by ratcheting. The coolant channels bulged toward the chamber centerline, resulting in progressive thinning of the wall during each cycle. The failures in the Amzirc alloy chambers were caused by low-cycle thermal fatigue. The zirconium in this alloy was not evenly distributed in the chamber materials. The life that was achieved was nominally the same as would have been predicted from OFHC copper isothermal test data.

Reliability aspects of a composite bolted scarf joint. [in wing skin splice

NASA Technical Reports Server (NTRS)

Reed, D. L.; Eisenmann, J. R.

1975-01-01

The design, fabrication, static test, and fatigue test of both tension and compression graphite-epoxy candidates for a wing splice representative of a next-generation transport aircraft was the objective of the reported research program. A single-scarf bolted joint was selected as the design concept. Test specimens were designed and fabricated to represent an upper-surface and a lower-surface panel containing the splice. The load spectrum was a flight-by-flight random-load history including ground-air-ground loads. The results of the fatigue testing indicate that, for this type of joint, the inherent fatigue resistance of the laminate is reflected in the joint behavior and, consequently, the rate of damage accumulation is very slow under realistic fatigue loadings.

CARES/Life Ceramics Durability Evaluation Software Enhanced for Cyclic Fatigue

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Powers, Lynn M.; Janosik, Lesley A.

1999-01-01

The CARES/Life computer program predicts the probability of a monolithic ceramic component's failure as a function of time in service. The program has many features and options for materials evaluation and component design. It couples commercial finite element programs--which resolve a component's temperature and stress distribution--to reliability evaluation and fracture mechanics routines for modeling strength-limiting defects. The capability, flexibility, and uniqueness of CARES/Life have attracted many users representing a broad range of interests and has resulted in numerous awards for technological achievements and technology transfer. Recent work with CARES/Life was directed at enhancing the program s capabilities with regards to cyclic fatigue. Only in the last few years have ceramics been recognized to be susceptible to enhanced degradation from cyclic loading. To account for cyclic loads, researchers at the NASA Lewis Research Center developed a crack growth model that combines the Power Law (time-dependent) and the Walker Law (cycle-dependent) crack growth models. This combined model has the characteristics of Power Law behavior (decreased damage) at high R ratios (minimum load/maximum load) and of Walker law behavior (increased damage) at low R ratios. In addition, a parameter estimation methodology for constant-amplitude, steady-state cyclic fatigue experiments was developed using nonlinear least squares and a modified Levenberg-Marquardt algorithm. This methodology is used to give best estimates of parameter values from cyclic fatigue specimen rupture data (usually tensile or flexure bar specimens) for a relatively small number of specimens. Methodology to account for runout data (unfailed specimens over the duration of the experiment) was also included.

Development of an Individualized Yoga Intervention to Address Fatigue in Hospitalized Children Undergoing Intensive Chemotherapy.

PubMed

Diorio, Caroline; Celis Ekstrand, Amanda; Hesser, Tanya; O'Sullivan, Cathy; Lee, Michelle; Schechter, Tal; Sung, Lillian

2016-09-01

Purpose Fatigue is an important problem in children receiving intensive chemotherapy and hematopoietic stem cell transplantation (HSCT). Exercise may be an effective intervention for fatigue. Individualized yoga represents an ideal intervention because it can be tailored according to an individual child's needs. Little is known about how to structure a standardized yoga program for intensivelytreated children. Therefore, this study describes the development of a yoga program and an approach to monitoring sessions suitable for hospitalized children receiving intensive chemotherapy or HSCT. Methods The yoga program was designed to increase mobility in hospitalized children and to provide children with relaxation techniques that could be used independently in a variety of environments. The program was founded on 4 key tenets: safety, adaptability, environmental flexibility, and appeal to children. We also developed quality and consistency assurance procedures. Results A menu format with a fixed structure was selected for the yoga program. Each yoga session contained up to 6 sections: breathing exercises, warmup exercises, yoga poses, balancing poses, cool-down poses, and final relaxation. Yoga instructors selected specific yoga poses for each session from a predetermined list organized by intensity level (low, moderate, or high). Monitoring procedures were developed using videotaping and multirater adjudication. Conclusion We created a standardized yoga program and an approach to monitoring that are now ready for incorporation in clinical trials. Future work should include the adaptation of the program to different pediatric populations and clinical settings. © The Author(s) 2016.

Relationship between cancer-related fatigue and physical activity in inpatient cancer rehabilitation.

PubMed

Kummer, Franziska; Catuogno, Silvio; Perseus, Josef M; Bloch, Wilhelm; Baumann, Freerk T

2013-08-01

Fatigue is a serious problem for the majority of patients with cancer. In this context, several studies have shown benefits of physical activity during and following treatment. However, uncertainties remain regarding the optimal type and duration of physical activity. Therefore, this study examined the relationship between cancer-related fatigue and physical activity in the course of inpatient rehabilitation. Fatigue (Multidimensional Fatigue Inventory) and physical activity (Freiburg Questionnaire of Physical Activity) were assessed in a consecutive series of 35 patients with cancer attending oncological inpatient rehabilitation during a six-month study period. The three-week rehabilitation program included daily exercise therapy consisting of aerobic endurance training, moderate resistance training, coordination exercises, relaxation training and individual physiotherapy. At discharge, a significant improvement in each dimension of cancer-related fatigue (p=0.001-0.003) and a significant increase of physical activity levels (p=0.001) were observed. A small, but significant negative correlation was found between cancer-related fatigue and the level of physical activity (R=-0.438, p=0.004). The largest effects were associated with a weekly energy expenditure of 3000 kcal through physical activity. The results support a non-linear dose-response relationship between cancer-related fatigue and physical activity. Since this is the first study providing specific exercise recommendations for an effective treatment of cancer-related fatigue in the context of inpatient rehabilitation, further research is required to validate the observed trends.

System-Level Heat Transfer Analysis, Thermal- Mechanical Cyclic Stress Analysis, and Environmental Fatigue Modeling of a Two-Loop Pressurized Water Reactor. A Preliminary Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohanty, Subhasish; Soppet, William; Majumdar, Saurin

This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable in April 2015 under the work package for environmentally assisted fatigue under DOE's Light Water Reactor Sustainability program. In this report, updates are discussed related to a system level preliminary finite element model of a two-loop pressurized water reactor (PWR). Based on this model, system-level heat transfer analysis and subsequent thermal-mechanical stress analysis were performed for typical design-basis thermal-mechanical fatigue cycles. The in-air fatigue lives of components, such as the hot and cold legs,more » were estimated on the basis of stress analysis results, ASME in-air fatigue life estimation criteria, and fatigue design curves. Furthermore, environmental correction factors and associated PWR environment fatigue lives for the hot and cold legs were estimated by using estimated stress and strain histories and the approach described in NUREG-6909. The discussed models and results are very preliminary. Further advancement of the discussed model is required for more accurate life prediction of reactor components. This report only presents the work related to finite element modelling activities. However, in between multiple tensile and fatigue tests were conducted. The related experimental results will be presented in the year-end report.« less

Mindfulness-Based Stress Reduction in Post-treatment Breast Cancer Patients: Immediate and Sustained Effects Across Multiple Symptom Clusters.

PubMed

Reich, Richard R; Lengacher, Cecile A; Alinat, Carissa B; Kip, Kevin E; Paterson, Carly; Ramesar, Sophia; Han, Heather S; Ismail-Khan, Roohi; Johnson-Mallard, Versie; Moscoso, Manolete; Budhrani-Shani, Pinky; Shivers, Steve; Cox, Charles E; Goodman, Matthew; Park, Jong

2017-01-01

Breast cancer survivors (BCS) face adverse physical and psychological symptoms, often co-occurring. Biologic and psychological factors may link symptoms within clusters, distinguishable by prevalence and/or severity. Few studies have examined the effects of behavioral interventions or treatment of symptom clusters. The aim of this study was to identify symptom clusters among post-treatment BCS and determine symptom cluster improvement following the Mindfulness-Based Stress Reduction for Breast Cancer (MBSR(BC)) program. Three hundred twenty-two Stage 0-III post-treatment BCS were randomly assigned to either a six-week MBSR(BC) program or usual care. Psychological (depression, anxiety, stress, and fear of recurrence), physical (fatigue, pain, sleep, and drowsiness), and cognitive symptoms and quality of life were assessed at baseline, six, and 12 weeks, along with demographic and clinical history data at baseline. A three-step analytic process included the error-accounting models of factor analysis and structural equation modeling. Four symptom clusters emerged at baseline: pain, psychological, fatigue, and cognitive. From baseline to six weeks, the model demonstrated evidence of MBSR(BC) effectiveness in both the psychological (anxiety, depression, perceived stress and QOL, emotional well-being) (P = 0.007) and fatigue (fatigue, sleep, and drowsiness) (P < 0.001) clusters. Results between six and 12 weeks showed sustained effects, but further improvement was not observed. Our results provide clinical effectiveness evidence that MBSR(BC) works to improve symptom clusters, particularly for psychological and fatigue symptom clusters, with the greatest improvement occurring during the six-week program with sustained effects for several weeks after MBSR(BC) training. Name and URL of Registry: ClinicalTrials.gov. Registration number: NCT01177124. Copyright © 2016. Published by Elsevier Inc.

Physical fitness and physical activity in fatigued and non-fatigued inflammatory bowel disease patients.

PubMed

Vogelaar, Lauran; van den Berg-Emons, Rita; Bussmann, Hans; Rozenberg, Robert; Timman, Reinier; van der Woude, Christien J

2015-01-01

To assess physical fitness and physical activity in inflammatory bowel disease (IBD) patients and whether fatigue is associated with impaired physical fitness and impaired physical activity. Ten patients with quiescent IBD and fatigue (fatigue group [FG]) based on the Checklist Individual Strength-Fatigue score of ≥35 were matched for age (±5 years) and sex with a non-fatigue group (NFG) with IBD. Physical fitness was measured with a cyclo-ergometric-based maximal exercise test, a submaximal 6-min walk test, and a dynamometer test to quantify the isokinetic muscle strength of the knee extensors and flexors. Level of physical activity was measured with an accelerometer-based activity monitor. The patients in both groups did not differ in regard to medication use, clinical characteristics, and body composition. However, medium-to-large effect sizes for impaired physical fitness (both cardiorespiratory fitness and muscle strength) and physical activity were seen between the patients in the FG and the NFG. Especially, intensity of physical activity was significantly lower in the FG patients compared with the NFG patients (effect size: 1.02; p = 0.037). Similar results were seen when outcomes of the FG and NFG were compared with reference values of the normal population. Fatigued IBD patients show an impaired physical fitness and physical activity compared with non-fatigued IBD patients. This gives directions for a physical component in fatigue in IBD patients. Therefore, these new insights into fatigue indicate that these patients might benefit from an exercise program to improve physical fitness and physical activity.

The role of insomnia in the treatment of chronic fatigue.

PubMed

Kallestad, Håvard; Jacobsen, Henrik B; Landrø, Nils Inge; Borchgrevink, Petter C; Stiles, Tore C

2015-05-01

The definition of Chronic Fatigue Syndrome (CFS) overlaps with definitions of insomnia, but there is limited knowledge about the role of insomnia in the treatment of chronic fatigue. To test if improvement of insomnia during treatment of chronic fatigue was associated with improved outcomes on 1) fatigue and 2) cortisol recovery span during a standardized stress exposure. Patients (n = 122) with chronic fatigue received a 3.5-week inpatient return-to-work rehabilitation program based on Acceptance and Commitment Therapy, and had been on paid sick leave>8 weeks due their condition. A physician and a psychologist examined the patients, assessed medication use, and SCID-I diagnoses. Patients completed self-report questionnaires measuring fatigue, pain, depression, anxiety, and insomnia before and after treatment. A subgroup (n = 25) also completed the Trier Social Stress Test for Groups (TSST-G) before and after treatment. Seven cortisol samples were collected during each test and cortisol spans for the TSST-G were calculated. A hierarchical regression analysis in nine steps showed that insomnia improvement predicted improvement in fatigue, independently of age, gender, improvement in pain intensity, depression and anxiety. A second hierarchical regression analysis showed that improvement in insomnia significantly predicted the cortisol recovery span after the TSST-G independently of improvement in fatigue. Improvement in insomnia severity had a significant impact on both improvement in fatigue and the ability to recover from a stressful situation. Insomnia severity may be a maintaining factor in chronic fatigue and specifically targeting this in treatment could increase treatment response. Copyright © 2014. Published by Elsevier Inc.

Usage of Parameterized Fatigue Spectra and Physics-Based Systems Engineering Models for Wind Turbine Component Sizing: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsons, Taylor; Guo, Yi; Veers, Paul

Software models that use design-level input variables and physics-based engineering analysis for estimating the mass and geometrical properties of components in large-scale machinery can be very useful for analyzing design trade-offs in complex systems. This study uses DriveSE, an OpenMDAO-based drivetrain model that uses stress and deflection criteria to size drivetrain components within a geared, upwind wind turbine. Because a full lifetime fatigue load spectrum can only be defined using computationally-expensive simulations in programs such as FAST, a parameterized fatigue loads spectrum that depends on wind conditions, rotor diameter, and turbine design life has been implemented. The parameterized fatigue spectrummore » is only used in this paper to demonstrate the proposed fatigue analysis approach. This paper details a three-part investigation of the parameterized approach and a comparison of the DriveSE model with and without fatigue analysis on the main shaft system. It compares loads from three turbines of varying size and determines if and when fatigue governs drivetrain sizing compared to extreme load-driven design. It also investigates the model's sensitivity to shaft material parameters. The intent of this paper is to demonstrate how fatigue considerations in addition to extreme loads can be brought into a system engineering optimization.« less

Establishment of new design criteria for GlidCop ® X-ray absorbers

DOE PAGES

Collins, Jeff T.; Nudell, Jeremy; Navrotski, Gary; ...

2017-02-20

Here, an engineering research program has been conducted at the Advanced Photon Source (APS) in order to determine the thermomechanical conditions that lead to crack formation in GlidCop ®, a material commonly used to fabricate X-ray absorbers at X-ray synchrotron facilities. This dispersion-strengthened copper alloy is a proprietary material and detailed technical data of interest to the synchrotron community is limited. The results from the research program have allowed new design criteria to be established for GlidCop ® X-ray absorbers based upon the thermomechanically induced fatigue behavior of the material. X-ray power from APS insertion devices was used to exposemore » 30 GlidCop ® samples to 10000 thermal loading cycles each under various beam power conditions, and all of the samples were metallurgically examined for crack presence/geometry. In addition, an independent testing facility was hired to measure temperature-dependent mechanical data and uniaxial mechanical fatigue data for numerous GlidCop ® samples. Data from these studies support finite element analysis (FEA) simulation and parametric models, allowing the development of a thermal fatigue model and the establishment of new design criteria so that the thermomechanically induced fatigue life of X-ray absorbers may be predicted. It is also demonstrated how the thermal fatigue model can be used as a tool to geometrically optimize X-ray absorber designs.« less

Crack propagation modelling for high strength steel welded structural details

NASA Astrophysics Data System (ADS)

Mecséri, B. J.; Kövesdi, B.

2017-05-01

Nowadays the barrier of applying HSS (High Strength Steel) material in bridge structures is their low fatigue strength related to yield strength. This paper focuses on the fatigue behaviour of a structural details (a gusset plate connection) made from NSS and HSS material, which is frequently used in bridges in Hungary. An experimental research program is carried out at the Budapest University of Technology and Economics to investigate the fatigue lifetime of this structural detail type through the same test specimens made from S235 and S420 steel grades. The main aim of the experimental research program is to study the differences in the crack propagation and the fatigue lifetime between normal and high strength steel structures. Based on the observed fatigue crack pattern the main direction and velocity of the crack propagation is determined. In parallel to the tests finite element model (FEM) are also developed, which model can handle the crack propagation. Using the measured strain data in the tests and the calculated values from the FE model, the approximation of the material parameters of the Paris law are calculated step-by-step, and their calculated values are evaluated. The same material properties are determined for NSS and also for HSS specimens as well, and the differences are discussed. In the current paper, the results of the experiments, the calculation method of the material parameters and the calculated values are introduced.

Establishment of new design criteria for GlidCop ® X-ray absorbers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, Jeff T.; Nudell, Jeremy; Navrotski, Gary

Here, an engineering research program has been conducted at the Advanced Photon Source (APS) in order to determine the thermomechanical conditions that lead to crack formation in GlidCop ®, a material commonly used to fabricate X-ray absorbers at X-ray synchrotron facilities. This dispersion-strengthened copper alloy is a proprietary material and detailed technical data of interest to the synchrotron community is limited. The results from the research program have allowed new design criteria to be established for GlidCop ® X-ray absorbers based upon the thermomechanically induced fatigue behavior of the material. X-ray power from APS insertion devices was used to exposemore » 30 GlidCop ® samples to 10000 thermal loading cycles each under various beam power conditions, and all of the samples were metallurgically examined for crack presence/geometry. In addition, an independent testing facility was hired to measure temperature-dependent mechanical data and uniaxial mechanical fatigue data for numerous GlidCop ® samples. Data from these studies support finite element analysis (FEA) simulation and parametric models, allowing the development of a thermal fatigue model and the establishment of new design criteria so that the thermomechanically induced fatigue life of X-ray absorbers may be predicted. It is also demonstrated how the thermal fatigue model can be used as a tool to geometrically optimize X-ray absorber designs.« less

The Effects of Performance Fatigability on Postural Control and Rehabilitation in the Older Patient

PubMed Central

Hassan, Mahdi; Bugnariu, Nicoleta

2016-01-01

Fatigue is common in older adults and has a significant effect on quality of life. Despite the high prevalence of fatigue in older individuals, several aspects are poorly understood. It is important to differentiate subjective fatigue complaints from fatigability of motor performance because the two are independent constructs with potentially distinct consequences on mobility. Performance fatigability is the magnitude of change in a performance criterion over a given time of task performance. Performance fatigability is a compulsory element of any strength training program, yet strength training is an important component of rehabilitation programs for older adults. The consequences of fatigability for older adults suggest that acute exercise of various types may result in acute impairments in postural control. The effects of performance fatigability on postural control in older adults are evaluated here to aid the rehabilitation clinician in making recommendations for evaluation of fall risks and exercise prescription. PMID:28154794

The Effects of Performance Fatigability on Postural Control and Rehabilitation in the Older Patient.

PubMed

Papa, Evan V; Hassan, Mahdi; Bugnariu, Nicoleta

2016-09-01

Fatigue is common in older adults and has a significant effect on quality of life. Despite the high prevalence of fatigue in older individuals, several aspects are poorly understood. It is important to differentiate subjective fatigue complaints from fatigability of motor performance because the two are independent constructs with potentially distinct consequences on mobility. Performance fatigability is the magnitude of change in a performance criterion over a given time of task performance. Performance fatigability is a compulsory element of any strength training program, yet strength training is an important component of rehabilitation programs for older adults. The consequences of fatigability for older adults suggest that acute exercise of various types may result in acute impairments in postural control. The effects of performance fatigability on postural control in older adults are evaluated here to aid the rehabilitation clinician in making recommendations for evaluation of fall risks and exercise prescription.

Fatigue of graphite/epoxy buffer strip panels with center cracks

NASA Technical Reports Server (NTRS)

Bigelow, C. A.

1985-01-01

The effects of fatigue loading on the behavior of graphite/epoxy panels with either S-Glass or Kevlar-49 buffer strips is studied. Buffer strip panels are fatigued and tested in tension to measure their residual strength with crack-like damage. Panels are made with 45/0/-45/90 sub 2s layup with either S-Glass or Kevlar-49 buffer strip material. The buffer strips are parallel to the loading direction and made by replacing narrow strips of the 0-degree graphite plies with strips of either 0-degree S-Glass/epoxy or Kevlar-49/epoxy on a one-for-one basis. The panels are subjected to a fatigue loading spectrum MINITWIST, the shortened version of the standardized load program for the wing lower surface of a transport aircraft. Two levels of maximum strain are used in the spectrum with three durations of the fatigue spectrum. One group of panels is preloaded prior to the application of the fatigue cycling. The preload consists of statistically loading the spectrum in tension until the crack-tip damage zone reaches the ajacent buffer strips. After fatigue loading, all specimens are statistically loaded in tension to failure to determine their residual strengths.

Effectiveness of a Pilot Mindfulness Program in Volunteers of a Breast Cancer Association.

PubMed

Cucarella, Sheila Pintado; Giannini, Marina Chiba

2016-10-01

It has been usually observed that medical and health personnel, volunteers, and social workers who work with cancer and chronic patients may have higher rates of compassion fatigue and symptoms of anxiety and depression. The purpose of this study was to examine the benefits of a pilot mindfulness program in a sample of 7 volunteers of a foundation that supports women with breast cancer. The variables analyzed were depression, anxiety, compassion fatigue, work stress, and negative and positive affect. The results showed that the mindfulness program had a positive impact, reducing the symptoms of anxiety and depression and increasing emotional well-being. Participants also reported that the program helped them be more relaxed, identify their emotions, enjoy their time and environment better, increasing the value of life, and facilitate communication among the volunteers. The program produced positive changes in participants, powering personal areas and increasing emotional well-being. © The Author(s) 2015.

Program for Weibull Analysis of Fatigue Data

NASA Technical Reports Server (NTRS)

Krantz, Timothy L.

2005-01-01

A Fortran computer program has been written for performing statistical analyses of fatigue-test data that are assumed to be adequately represented by a two-parameter Weibull distribution. This program calculates the following: (1) Maximum-likelihood estimates of the Weibull distribution; (2) Data for contour plots of relative likelihood for two parameters; (3) Data for contour plots of joint confidence regions; (4) Data for the profile likelihood of the Weibull-distribution parameters; (5) Data for the profile likelihood of any percentile of the distribution; and (6) Likelihood-based confidence intervals for parameters and/or percentiles of the distribution. The program can account for tests that are suspended without failure (the statistical term for such suspension of tests is "censoring"). The analytical approach followed in this program for the software is valid for type-I censoring, which is the removal of unfailed units at pre-specified times. Confidence regions and intervals are calculated by use of the likelihood-ratio method.

Life extending control for rocket engines

NASA Technical Reports Server (NTRS)

Lorenzo, C. F.; Saus, J. R.; Ray, A.; Carpino, M.; Wu, M.-K.

1992-01-01

The concept of life extending control is defined. A brief discussion of current fatigue life prediction methods is given and the need for an alternative life prediction model based on a continuous functional relationship is established. Two approaches to life extending control are considered: (1) the implicit approach which uses cyclic fatigue life prediction as a basis for control design; and (2) the continuous life prediction approach which requires a continuous damage law. Progress on an initial formulation of a continuous (in time) fatigue model is presented. Finally, nonlinear programming is used to develop initial results for life extension for a simplified rocket engine (model).

Fatigue of titanium alloys in a supersonic-cruise airplane environment

NASA Technical Reports Server (NTRS)

Imig, L. A.

1976-01-01

The test programs conducted by several aerospace companies and NASA, summarized in this paper, studied several titanium materials previously identified as having high potential for application to supersonic cruise airplane structures. These studies demonstrate that the temperature (560 K) by itself produced no significant degradation of the materials. However, the fatigue resistance of titanium-alloy structures, in which thermal and loading effects are combined, has been studied insufficiently. The predominant topic for future study of fatigue problems in Mach 3 structures should be the influences of thermal stress particularly, the effects of thermal stress on failure location.

NASA Human Research Program: Behavioral Health and Performance Program Element

NASA Technical Reports Server (NTRS)

Leveton, Lauren B.

2009-01-01

This viewgraph presentation reviews the performance errors associated with sleep loss, fatigue and psychomotor factors during manned space flight. Short and long term behavioral health factors are also addressed

The Effects of Exercise Education Intervention on the Exercise Behaviour, Depression, and Fatigue Status of Chronic Kidney Disease Patients

ERIC Educational Resources Information Center

Kao, Yu-Hsiu; Huang, Yi-Ching; Chen, Pei-Ying; Wang, Kuo-Ming

2012-01-01

Purpose: The purpose of this paper is to investigate the effects of an exercise education intervention on exercise behavior, depression and fatigue status of chronic kidney disease (CKD) patients. Design/methodology/approach: This was a pilot study using an exercise education program as an intervention for CKD patients. The authors used the…

Quantitative high-speed laryngoscopic analysis of vocal fold vibration in fatigued voice of young karaoke singers.

PubMed

Yiu, Edwin M-L; Wang, Gaowu; Lo, Andy C Y; Chan, Karen M-K; Ma, Estella P-M; Kong, Jiangping; Barrett, Elizabeth Ann

2013-11-01

The present study aimed to determine whether there were physiological differences in the vocal fold vibration between nonfatigued and fatigued voices using high-speed laryngoscopic imaging and quantitative analysis. Twenty participants aged from 18 to 23 years (mean, 21.2 years; standard deviation, 1.3 years) with normal voice were recruited to participate in an extended singing task. Vocal fatigue was induced using a singing task. High-speed laryngoscopic image recordings of /i/ phonation were taken before and after the singing task. The laryngoscopic images were semiautomatically analyzed with the quantitative high-speed video processing program to extract indices related to the anteroposterior dimension (length), transverse dimension (width), and the speed of opening and closing. Significant reduction in the glottal length-to-width ratio index was found after vocal fatigue. Physiologically, this indicated either a significantly shorter (anteroposteriorly) or a wider (transversely) glottis after vocal fatigue. The high-speed imaging technique using quantitative analysis has the potential for early identification of vocally fatigued voice. Copyright © 2013 The Voice Foundation. All rights reserved.

Experimental Evaluation of Fatigue Crack Initiation from Corroded Hemispherical Notches in Aerospace Structural Materials

NASA Technical Reports Server (NTRS)

Garcia, Daniel B.; Forman, Royce; Shindo, David

2010-01-01

A test program was developed and executed to evaluate the influence of corroded hemispherical notches on the fatigue crack initiation and propagation in aluminum 7075-T7351, 4340 steel, and D6AC steel. Surface enhancements such as shot peening and laser shock peening were also incorporated as part of the test effort with the intent of improving fatigue performance. In addition to the testing, fracture mechanics and endurance limit based analysis methods were evaluated to characterize the results with the objective of challenging typical assumptions used in modeling fatigue cracks from corrosion pits. The results specifically demonstrate that the aluminum and steel alloys behave differently with respect to fatigue crack initiation from hemispherical corrosion pits. The aluminum test results were bounded by the fracture mechanics and endurance limit models while exhibiting a general insensitivity to the residual stress field generated by shot peening. The steel specimens were better characterized by the endurance limit fatigue properties and did exhibit sensitivities to residual stresses from the shot peening and laser shock peening

Are general practitioners well informed about fibromyalgia?

PubMed

Kianmehr, Nahid; Haghighi, Anousheh; Bidari, Ali; Sharafian Ardekani, Yaser; Karimi, Mohammad Ali

2017-12-01

Fibromyalgia syndrome (FMS) is a common rheumatologic disorder characterized by easy fatigability, widespread musculoskeletal pain and sleep disorder. In spite of its high prevalence, general practitioners, as primary care providers, seem to have inadequate knowledge about FMS. This study aimed to assess Iranian general practitioners' knowledge about FMS and its treatment. A detailed questionnaire (including items on signs and symptoms, diagnostic criteria and treatment) was completed by 190 general practitioners (54.7% male; mean age: 41 years). Data analysis was performed with SPSS for Windows 15.0 and awareness about all aspects of FMS was reported as percentages. About one-third (30%) of the participants had seen at least one case of FMS during their practice. Most subjects (62.7%) claimed to know 1-6 tender points. Only 3.2% knew 16-18 points. The common proposed symptoms of FMS were widespread pain (72.6%), excessive fatigue (72.6%), weakness (60.5%), sleep disorder (36.3%), anxiety (34.7%) and depression (34.2%). Wrong symptoms including elevated erythrocyte sedimentation rate and C-reactive protein, arthritis, joint swelling, weight loss and abnormal radiologic findings were selected by 27.9%, 18.9%, 14.7%, 12.6% and 2.1% of the physicians, respectively. Moreover, selective serotonin reuptake inhibitors, tricyclic antidepressant and pregabalin were identified as treatment options for FMS by, respectively, 45.8%, 22.1% and 15.3% of the participants. Finally, 52.1% and 23.7% of the subjects incorrectly considered nonsteroidal anti-inflammatory drugs and corticosteroids as treatment modalities for FMS. Iranian general practitioners are not well informed about FMS. Therefore, FMS should be specifically integrated in continuing medical education programs and undergraduate medical training curriculum. © 2015 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Fibromyalgia syndrome: considerations for dental hygienists.

PubMed

Walters, Amber; Tolle, Susan L; McCombs, Gayle M

2015-04-01

Fibromyalgia syndrome (FMS) is a neurosensory disorder characterized by widespread musculoskeletal pain. Typically persistent fatigue, depression, limb stiffness, non-refreshing sleep and cognitive deficiencies are also experienced. Oral symptoms and pain are common, requiring adaptations in patient management strategies and treatment interventions. Appropriate dental hygiene care of patients suffering with this disorder is contingent upon an understanding of disease epidemiology, pathophysiology, clinical characteristics, oral signs and symptoms, as well as treatment approaches. With this information dental hygienists will be better prepared to provide appropriate and effective treatment to patients with FMS. Copyright © 2015 The American Dental Hygienists’ Association.

Association of fibromyalgia characteristics in patients with non-metastatic breast cancer and the protective role of resilience.

PubMed

Schrier, Michal; Amital, Daniela; Arnson, Yoav; Rubinow, Alan; Altaman, Arie; Nissenabaum, Bella; Amital, Howard

2012-10-01

Cancer patients often complain about weakness, fatigue, and pain. The aim of this study was to assess the features of the fibromyalgia syndrome (FMS) characteristics in patients with non-metastatic breast cancer. The study group included 40 women whose age ranged from 40 to 70 years with Stages 0-3 breast cancer. The control group included 40 healthy women matched by age. A diagnosis of FMS was established based on medical history, physical examination, and the Fibromyalgia Impact Questionnaire (FIQ). Pain measures and functional factors were evaluated by the Brief Pain Inventory and the Sheehan Questionnaire. Resilience was assessed by Antanovsky's Sense of Coherence Questionnaire. Psychiatric disturbances were tested by the MINI Questionnaire and Hamilton questionnaires for depression and anxiety. The prevalence of chronic pain was higher in the study group. Statistically significant differences were also found between the group regarding pain, fatigue, and functional measures. The prevalence of depressive or anxious mood, measured by the Hamilton questionnaires, was strongly related to FMS characteristics reflected by FIQ scores (r = 0.79 between FIQ and the Hamilton Depression Index and r = 0.75 between FIQ and the Hamilton Anxiety Scale). The sense of coherence measure for these patients demonstrated an inverse correlation with pain, fatigue, and functional capability. Women with breast cancer tend to develop chronic widespread pain syndromes more often than do healthy women.

Biomechanical fatigue analysis of an advanced new carbon fiber/flax/epoxy plate for bone fracture repair using conventional fatigue tests and thermography.

PubMed

Bagheri, Zahra S; El Sawi, Ihab; Bougherara, Habiba; Zdero, Radovan

2014-07-01

The current study is part of an ongoing research program to develop an advanced new carbon fiber/flax/epoxy (CF/flax/epoxy) hybrid composite with a “sandwich structure” as a substitute for metallic materials for orthopedic long bone fracture plate applications. The purpose of this study was to assess the fatigue properties of this composite, since cyclic loading is one of the main types of loads carried by a femur fracture plate during normal daily activities. Conventional fatigue testing, thermographic analysis, and scanning electron microscopy (SEM) were used to analyze the damage progress that occurred during fatigue loading. Fatigue strength obtained using thermography analysis (51% of ultimate tensile strength) was confirmed using the conventional fatigue test (50–55% of ultimate tensile strength). The dynamic modulus (E⁎) was found to stay almost constant at 47 GPa versus the number of cycles, which can be related to the contribution of both flax/epoxy and CF/epoxy laminae to the stiffness of the composite. SEM images showed solid bonding at the CF/epoxy and flax/epoxy laminae, with a crack density of only 0.48% for the plate loaded for 2 million cycles. The current composite plate showed much higher fatigue strength than the main loads experienced by a typical patient during cyclic activities; thus, it may be a potential candidate for bone fracture plate applications. Moreover, the fatigue strength from thermographic analysis was the same as that obtained by the conventional fatigue tests, thus demonstrating its potential use as an alternate tool to rapidly evaluate fatigue strength of composite biomaterials.

Biomechanical fatigue analysis of an advanced new carbon fiber/flax/epoxy plate for bone fracture repair using conventional fatigue tests and thermography.

PubMed

Bagheri, Zahra S; El Sawi, Ihab; Bougherara, Habiba; Zdero, Radovan

2014-07-01

The current study is part of an ongoing research program to develop an advanced new carbon fiber/flax/epoxy (CF/flax/epoxy) hybrid composite with a "sandwich structure" as a substitute for metallic materials for orthopedic long bone fracture plate applications. The purpose of this study was to assess the fatigue properties of this composite, since cyclic loading is one of the main types of loads carried by a femur fracture plate during normal daily activities. Conventional fatigue testing, thermographic analysis, and scanning electron microscopy (SEM) were used to analyze the damage progress that occurred during fatigue loading. Fatigue strength obtained using thermography analysis (51% of ultimate tensile strength) was confirmed using the conventional fatigue test (50-55% of ultimate tensile strength). The dynamic modulus (E(⁎)) was found to stay almost constant at 47GPa versus the number of cycles, which can be related to the contribution of both flax/epoxy and CF/epoxy laminae to the stiffness of the composite. SEM images showed solid bonding at the CF/epoxy and flax/epoxy laminae, with a crack density of only 0.48% for the plate loaded for 2 million cycles. The current composite plate showed much higher fatigue strength than the main loads experienced by a typical patient during cyclic activities; thus, it may be a potential candidate for bone fracture plate applications. Moreover, the fatigue strength from thermographic analysis was the same as that obtained by the conventional fatigue tests, thus demonstrating its potential use as an alternate tool to rapidly evaluate fatigue strength of composite biomaterials. Copyright © 2014 Elsevier Ltd. All rights reserved.

One-Year Longitudinal Study of Fatigue, Cognitive Functions, and Quality of Life After Adjuvant Radiotherapy for Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noal, Sabine; Clinical Research Department, Centre Francois Baclesse, Caen; Levy, Christelle

Purpose: Most patients with localized breast cancer (LBC) who take adjuvant chemotherapy (CT) complain of fatigue and a decrease in quality of life during or after radiotherapy (RT). The aim of this longitudinal study was to compare the impact of RT alone with that occurring after previous CT on quality of life. Methods and Materials: Fatigue (the main endpoint) and cognitive impairment were assessed in 161 CT-RT and 141 RT patients during RT and 1 year later. Fatigue was assessed with Functional Assessment of Cancer Therapy-General questionnaires, including breast and fatigue modules. Results: At baseline, 60% of the CT-RT patientsmore » expressed fatigue vs. 33% of the RT patients (p <0.001). Corresponding values at the end of RT were statistically similar (61% and 53%), and fatigue was still reported at 1 year by more than 40% of patients in both groups. Risk factors for long-term fatigue included depression (odds ratio [OR] = 6), which was less frequent in the RT group at baseline (16% vs. 28 %, respectively, p = 0.01) but reached a similar value at the end of RT (25% in both groups). Initial mild cognitive impairments were reported by RT (34 %) patients and CT-RT (24 %) patients and were persistent at 1 year for half of them. No biological disorders were associated with fatigue or cognitive impairment. Conclusions: Fatigue was the main symptom in LBC patients treated with RT, whether they received CT previously or not. The correlation of persistent fatigue with initial depressive status favors administering medical and psychological programs for LBC patients treated with CT and/or RT, to identify and manage this main quality-of-life-related symptom.« less

Screening Poststroke Fatigue; Feasibility and Validation of an Instrument for the Screening of Poststroke Fatigue throughout the Rehabilitation Process.

PubMed

Kruithof, Nena; Van Cleef, Melanie Hubertina Maria; Rasquin, Sascha Maria Cornelia; Bovend'Eerdt, Thamar Johannes Henricus

2016-01-01

Our objective is to investigate the feasibility and validity of a new instrument to screen for determinants of poststroke fatigue during the rehabilitation process. This prospective cohort study was conducted within the stroke department of a rehabilitation center. The participants in the study were postacute adult stroke patients. The Detection List Fatigue (DLF)was administered 2 weeks after the start of the rehabilitation program and again 6 weeks later. To determine the construct validity, the Hospital Anxiety and Depression Scale, the Checklist Individual Strength subscale fatigue, and the Fatigue Severity Scale--7-item version were administered. A fatigue rating scale was used to measure the patients' fatigue experience. Frequency analyses of the number of patients reporting poststroke fatigue determinants according to the DLF were performed. One hundred seven patients (mean age 60 years) without severe communication difficulties were included in the study. The DLF was easy to understand and quick to administer. The DLF showed good internal consistency (Cronbach's alpha: .79 and .87), high convergent validity (rs = .85 and rs = .79), and good divergent validity (rs = .31 and rs = .45). The majority of the patients (88.4%-90.2%) experienced at least 2 poststroke fatigue (PSF) determinants,of which "sleeping problem" was most frequently reported. The DLF is a feasible and valid instrument for the screening of PSF determinants throughout the rehabilitation process in stroke patients. Future studies should investigate whether the use of the list in determining a treatment plan prevents the development of PSF.

Investigating daily fatigue scores during two-week offshore day shifts.

PubMed

Riethmeister, Vanessa; Bültmann, Ute; Gordijn, Marijke; Brouwer, Sandra; de Boer, Michiel

2018-09-01

This study examined daily scores of fatigue and circadian rhythm markers over two-week offshore day shift periods. A prospective cohort study among N = 60 offshore day-shift workers working two-week offshore shifts was conducted. Offshore day shifts lasted from 07:00 - 19:00 h. Fatigue was measured objectively with pre- and post-shift scores of the 3-minute psychomotor vigilance tasks (PVT-B) parameters (reaction times, number of lapses, errors and false starts) and subjectively with pre- and post-shift Karolinska Sleepiness Scale (KSS) ratings. Evening saliva samples were collected on offshore days 2,7 and 13 to measure circadian rhythm markers such as dim-light melatonin onset times and cortisol. Generalized and linear mixed model analyses were used to examine daily fatigue scores over time. Complete data from N = 42 offshore day shift workers was analyzed. Daily parameters of objective fatigue, PVT-B scores (reaction times, average number of lapses, errors and false starts), remained stable over the course of the two-week offshore day shifts. Daily subjective post-shift fatigue scores significantly increased over the course of the two-week offshore shifts. Each day offshore was associated with an increased post-shift subjective fatigue score of 0.06 points (95%CI: .03 - .09 p < .001). No significant statistical differences in subjective pre-shift fatigue scores were found. Neither a circadian rhythm phase shift of melatonin nor an effect on the pattern and levels of evening cortisol was found. Daily parameters of objective fatigue scores remained stable over the course of the two-week offshore day shifts. Daily subjective post-shift fatigue scores significantly increased over the course of the two-week offshore shifts. No significant changes in circadian rhythm markers were found. Increased post-shift fatigue scores, especially during the last days of an offshore shift, should be considered and managed in (offshore) fatigue risk management programs and fatigue risk prediction models. Copyright © 2018 Elsevier Ltd. All rights reserved.

Perceptions of the 2011 ACGME duty hour requirements among residents in all core programs at a large academic medical center.

PubMed

Sandefur, Benjamin J; Shewmaker, Diana M; Lohse, Christine M; Rose, Steven H; Colletti, James E

2017-11-10

The Accreditation Council for Graduate Medical Education (ACGME) implemented revisions to resident duty hour requirements (DHRs) in 2011 to improve patient safety and resident well-being. Perceptions of DHRs have been reported to vary by training stage and specialty among internal medicine and general surgery residents. The authors explored perceptions of DHRs among all residents at a large academic medical center. The authors administered an anonymous cross-sectional survey about DHRs to residents enrolled in all ACGME-accredited core residency programs at their institution. Residents were categorized as medical and pediatric, surgery, or other. In total, 736 residents representing 24 core specialty residency programs were surveyed. The authors received responses from 495 residents (67%). A majority reported satisfaction (78%) with DHRs and believed DHRs positively affect their training (73%). Residents in surgical specialties and in advanced stages of training were significantly less likely to view DHRs favorably. Most respondents believed fatigue contributes to errors (89%) and DHRs reduce both fatigue (80%) and performance of clinical duties while fatigued (74%). A minority of respondents (37%) believed that DHRs decrease medical errors. This finding may reflect beliefs that handovers contribute more to errors than fatigue (41%). Negative perceived effects included diminished patient familiarity and continuity of care (62%) and diminished clinical educational experiences for residents (41%). A majority of residents reported satisfaction with the 2011 DHRs, although satisfaction was significantly less among residents in surgical specialties and those in advanced stages of training.

Small-crack effects in high-strength aluminum alloys

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.; Wu, X. R.; Venneri, S. L.; Li, C. G.

1994-01-01

The National Aeronautics and Space Administration and the Chinese Aeronautical Establishment participated in a Fatigue and Fracture Mechanics Cooperative Program. The program objectives were to identify and characterize crack initiation and growth of small cracks (10 microns to 2 mm long) in commonly used US and PRC aluminum alloys, to improve fracture mechanics analyses of surface- and corner-crack configurations, and to develop improved life-prediction methods. Fatigue and small-crack tests were performed on single-edgenotch tension (SENT) specimens and large-crack tests were conducted on center-crack tension specimens for constant-amplitude (stress ratios of -1, 0, and 0.5) and Mini-TWIST spectrum loading. The plastic replica method was used to monitor the initiation and growth of small fatigue cracks at the semicircular notch. Crack growth results from each laboratory on 7075-T6 bare and LC9cs clad aluminum alloys agreed well and showed that fatigue life was mostly crack propagation from a material defect (inclusion particles or void) or from the cladding layer. Finite-element and weight-function methods were used to determine stress intensity factors for surface and corner cracks in the SENT specimens. Equations were then developed and used in a crack growth and crack-closure model to correlate small- and large-crack data and to make life predictions for various load histories. The cooperative program produced useful experimental data and efficient analysis methods for improving life predictions. The results should ultimately improve aircraft structural reliability and safety.

Effect of Meaningful Recognition on Critical Care Nurses' Compassion Fatigue.

PubMed

Kelly, Lesly A; Lefton, Cindy

2017-11-01

As caregivers in high-pressure environments, critical care nurses are at risk for burnout and secondary trauma-components of compassion fatigue. Recent findings have increased understanding of the phenomena, specifically that satisfaction and meaningful recognition may play a role in reducing burnout and raising compassion satisfaction; however, no large multisite studies of compassion fatigue have been conducted. To examine the effect of meaningful recognition and other predictors on compassion fatigue in a multicenter national sample of critical care nurses. A quantitative, descriptive online survey was completed by 726 intensive care unit nurses in 14 hospitals with an established meaningful recognition program and 410 nurses in 10 hospitals without such a program. Site coordinators at each hospital coordinated distribution of the survey to nurses to assess multiple predictors against outcomes, measured by the Professional Quality of Life Scale. Cross-validation and linear regression modeling were conducted to determine significant predictors of burnout, secondary traumatic stress, and compassion satisfaction. Similar levels of burnout, secondary traumatic stress, compassion satisfaction, overall satisfaction, and intent to leave were reported by nurses in hospitals with and without meaningful recognition programs. Meaningful recognition was a significant predictor of decreased burnout and increased compassion satisfaction. Additionally, job satisfaction and job enjoyment were highly predictive of decreased burnout, decreased secondary traumatic stress, and increased compassion satisfaction. In addition to acknowledging and valuing nurses' contributions to care, meaningful recognition could reduce burnout and boost compassion satisfaction. ©2017 American Association of Critical-Care Nurses.

Efficacy of rehabilitation with Tai Ji Quan in an Italian cohort of patients with Fibromyalgia Syndrome.

PubMed

Maddali Bongi, Susanna; Paoletti, Gianluca; Calà, Michael; Del Rosso, Angela; El Aoufy, Khadija; Mikhaylova, Svetlana

2016-08-01

Fibromyalgia Syndrome (FMS) is characterized by musculoskeletal pain, muscle tenderness leading to disability, impaired quality of life (QoL), fatigue and it is accompanied by sleep disorders and psychological distress. Mind body therapies (MBT), such as Tai Ji Quan (TJQ), use different techniques to facilitate the ability of the mind to influence disease characteristics and symptoms. Some studies showed that TJQ, in patients with rheumatic diseases, particularly FMS, improved QoL, disability and psychological distress. To evaluate the efficacy of TJQ on disability, QoL, fatigue, sleep and psychological distress in an Italian cohort of FMS patients. We enrolled 44 FMS patients: 22 patients (Experimental Group) participated to a course of Tai Ji Quan style of (2/week for 16 weeks); 22 patients (Control Group) participated to an educational course about FMS (2/week for 16 weeks). At baseline (T0) and at the end of treatment (T1), patients were assessed for disability [Fibromyalgia Impact Questionnaire (FIQ), Health Assessment Questionnaire (HAQ)], Quality of Life [Short-Form 36 (SF36)], fatigue [Functional Assessment of Chronic Illness-Fatigue (FACIT-F)], pain [Widespread Pain Index (WPI)], tenderness [Tender Points (TP)], Sleep Quality [Pittsburgh Sleep Quality Index (PSQI)] and mood disorders [Hospital Anxiety and Depression Scale (HADS)]. At T1 versus T0, patients of the Experimental Group showed a significant improvement in FIQ, FACIT, SF36 (Summary Physical Index, Physical activity, physical role, bodily pain, general health, vitality, emotional role limitations), in WPI, TP, PSQI (total, sleep duration, and sleep disturbance) and HADS (total score and anxiety subscale), while Patients in the Control Group did not improve in any parameter. In FMS patients TJQ, if performed by an expert physiotherapist, should be regarded as an effective rehabilitation method. Copyright © 2016 Elsevier Ltd. All rights reserved.

Learning to live on a Mars day: fatigue countermeasures during the Phoenix Mars Lander mission.

PubMed

Barger, Laura K; Sullivan, Jason P; Vincent, Andrea S; Fiedler, Edna R; McKenna, Laurence M; Flynn-Evans, Erin E; Gilliland, Kirby; Sipes, Walter E; Smith, Peter H; Brainard, George C; Lockley, Steven W

2012-10-01

To interact with the robotic Phoenix Mars Lander (PML) spacecraft, mission personnel were required to work on a Mars day (24.65 h) for 78 days. This alien schedule presents a challenge to Earth-bound circadian physiology and a potential risk to workplace performance and safety. We evaluated the acceptability, feasibility, and effectiveness of a fatigue management program to facilitate synchronization with the Mars day and alleviate circadian misalignment, sleep loss, and fatigue. Operational field study. PML Science Operations Center. Scientific and technical personnel supporting PML mission. Sleep and fatigue education was offered to all support personnel. A subset (n = 19) were offered a short-wavelength (blue) light panel to aid alertness and mitigate/reduce circadian desynchrony. They were assessed using a daily sleep/work diary, continuous wrist actigraphy, and regular performance tests. Subjects also completed 48-h urine collections biweekly for assessment of the circadian 6-sulphatoxymelatonin rhythm. Most participants (87%) exhibited a circadian period consistent with adaptation to a Mars day. When synchronized, main sleep duration was 5.98 ± 0.94 h, but fell to 4.91 ± 1.22 h when misaligned (P < 0.001). Self-reported levels of fatigue and sleepiness also significantly increased when work was scheduled at an inappropriate circadian phase (P < 0.001). Prolonged wakefulness (≥ 21 h) was associated with a decline in performance and alertness (P < 0.03 and P < 0.0001, respectively). The ability of the participants to adapt successfully to the Mars day suggests that future missions should utilize a similar circadian rhythm and fatigue management program to reduce the risk of sleepiness-related errors that jeopardize personnel safety and health during critical missions.

Effect of aerobic exercise training on fatigue and physical activity in patients with pulmonary arterial hypertension.

PubMed

Weinstein, Ali A; Chin, Lisa M K; Keyser, Randall E; Kennedy, Michelle; Nathan, Steven D; Woolstenhulme, Joshua G; Connors, Gerilynn; Chan, Leighton

2013-05-01

To investigate the effectiveness of an exercise intervention for decreasing fatigue severity and increasing physical activity in individuals with pulmonary arterial hypertension (PAH). A small, phase 2 randomized clinical trial of the effect of aerobic exercise training on fatigue severity and physical activity in patients with idiopathic or PAH associated with other conditions was conducted. Twenty-four patients with PAH (24 female; age: 54.4 ± 10.4 years; BMI: 30.8 ± 7.2 kg/m(2)) participated in the study. A convenience sample was recruited in which 9% (28 of 303) of screened patients were enrolled. The project was carried out in a clinical pulmonary rehabilitation clinic during existing pulmonary rehabilitation program sessions. Patients with PH were randomized into a 10-week program that consisted of patient education only or patient education plus an aerobic exercise-training regimen. Both groups received 20 lectures, two per week over the 10-weeks, on topics related to PAH and its management. The aerobic exercise training consisted of 24-30 sessions of treadmill walking for 30-45 min per session at an intensity of 70-80% of heart rate reserve, three days per week over the 10 weeks. After 10-weeks of intervention, patients receiving aerobic exercise training plus education reported routinely engaging in higher levels of physical activity (p < 0.05) and a decrease in fatigue severity (p = 0.03). Patients in the education only group did not report changes in fatigue severity or participation in physical activity. The 10-week aerobic exercise training intervention resulted in increased physical activity and decreased fatigue in individuals with PAH. ClinicalTrials.gov Identifier: NCT00678821. Copyright © 2013 Elsevier Ltd. All rights reserved.

Impact of the Arthritis Foundation’s Walk With Ease Program on Arthritis Symptoms in African Americans

PubMed Central

Wyatt, Brooke; Mingo, Chivon A.; Waterman, Mary B.; White, Patience; Cleveland, Rebecca J.

2014-01-01

Introduction Inadequate program design and lack of access to evidence-based programs are major barriers to the management of chronic diseases such as arthritis, particularly for African Americans. This study evaluates the effectiveness of the Arthritis Foundation’s Walk With Ease Program (WWE) in a subsample of African Americans who were part of a larger study that established evidence of the program’s efficacy. Methods Participants were African Americans (N = 117) with self-reported arthritis who chose to participate in either a self-directed (n = 68) or group (n = 49) 6-week WWE program. Arthritis-related symptoms (ie, pain, fatigue, stiffness; measured using visual analog scales) were assessed at baseline, 6 weeks, and 1 year. Independent samples t tests were conducted to examine group differences (ie, self-directed vs group) in arthritis-related symptoms at baseline, and paired sample t tests were conducted to examine differences over time (ie, baseline to 6 weeks and baseline to 1 year) in symptoms. Satisfaction was examined by descriptive statistics. Results Younger, more educated individuals chose the self-directed format (P < .001, P = .008; respectively). After the 6-week intervention, participants reported a decrease in pain (P < .001), fatigue (P = .002), and stiffness (P < .001). At 1 year, the decrease in pain (P = .04) and stiffness (P = .002) remained constant. Overall, participants were satisfied with both program formats. Conclusion The individualized and group formats of the WWE program improved arthritis-related pain, fatigue, and stiffness in African Americans. Culturally appealing arthritis interventions ultimately may increase the use of existing arthritis interventions. PMID:25393747

Factors associated with fatigue in acquired immunodeficiency syndrome patients with antiretroviral drug adverse reactions: a retrospective study.

PubMed

Liu, Zhibin; Yang, Jiping; Liu, Huijuan; Jin, Yantao

2013-06-01

To retrospectively study the prevalence of fatigue and factors associated with fatigue among acquired immunodeficiency syndrome (AIDS) patients with antiretroviral drug adverse reactions. Data were collected from case report forms (CRFs) for a project funded by the 11th National 5-year Special Science and Technology Program on Major Infectious Diseases. Fatigue was defined by patient self-report. The outcomes were the prevalence of fatigue and the potential risk factors of fatigue. Univariate and multivariate logistic regression analyses were conducted to identify the factors associated with fatigue. Among the 228 subjects, the prevalence of fatigue was 86.8%. In univariate analysis, the significant differences in demographic characteristics between patients with and without fatigue were: gender [OR = 2.29; 95% CI (1.05-4.98)], education level [OR = 0.40; 95% CI (0.18-0.85)], anemia [OR = 3.80; 95% CI (1.27-11.31)], time of HIV diagnosis [OR = 0.29; 95% CI (0.13-0.65)], and route of infection [OR = 0.14; 95% CI (0.06-0.32)]. Abnormal taste and rapid pulse were more commonly seen in patients with fatigue (P < 0.05), while abdominal distension and lumbar soreness were encountered less often in patients with fatigue (P < 0.05). Multivariate analysis showed that the four main factors associated with fatigue were anemia [OR = 3.50; 95% CI (1.01-12.15)], route of infection [OR = 3.40; 95% CI (1.21-9.58); P = 0.02 < 0.05], lumbar soreness [OR = 0.06; 95% CI (0.02-0.18); P = 0.000 < 0.05], and rapid pulse [OR = 10.58; 95% CI (2.16-51.75); P = 0.004 < 0.05]. This study demonstrated that fatigue is common (86.8% prevalence) in AIDS patients with antiretroviral drug adverse reactions, and that anemia, route of infection (i.e., non-commercial blood donation) and rapid pulse were risk factors, while lumbar soreness was a protective factor related to fatigue. More attention should be paid to fatigue and more efforts should be made to find ways to prevent, control and eliminate this symptom in AIDS patients with antiretroviral drug adverse reactions.

Fatigue Solutions for Maintenance: From Science to Workplace Reality

DTIC Science & Technology

2011-12-01

John Hall IAMAW Jim Hein AWP-204 William (Bill) Johnson AIR-100 Charles (Bob) Kelley AJW-341 Daniel Mollicone Pulsar Informatics, Inc. Thomas...That Fit Industry. Dr. Daniel Mollicone, President and Chief Executive Officer for Pulsar Informatics, Inc., presented research on the use of...FAA Maintenance Fatigue applied R&D program has worked with Pulsar Informatics to develop a software system that helps individuals assess their

A computer program for cyclic plasticity and structural fatigue analysis

NASA Technical Reports Server (NTRS)

Kalev, I.

1980-01-01

A computerized tool for the analysis of time independent cyclic plasticity structural response, life to crack initiation prediction, and crack growth rate prediction for metallic materials is described. Three analytical items are combined: the finite element method with its associated numerical techniques for idealization of the structural component, cyclic plasticity models for idealization of the material behavior, and damage accumulation criteria for the fatigue failure.

The Effect of Hole Quality on the Fatigue Life of 2024-T3 Aluminum Alloy Sheet

NASA Technical Reports Server (NTRS)

Everett, Richard A., Jr.

2004-01-01

This paper presents the results of a study whose main objective was to determine which type of fabrication process would least affect the fatigue life of an open-hole structural detail. Since the open-hole detail is often the fundamental building block for determining the stress concentration of built-up structural parts, it is important to understand any factor that can affect the fatigue life of an open hole. A test program of constant-amplitude fatigue tests was conducted on five different sets of test specimens each made using a different hole fabrication process. Three of the sets used different mechanical drilling procedures while a fourth and fifth set were mechanically drilled and then chemically polished. Two sets of specimens were also tested under spectrum loading to aid in understanding the effects of residual compressive stresses on fatigue life. Three conclusions were made from this study. One, the residual compressive stresses caused by the hole-drilling process increased the fatigue life by two to three times over specimens that were chemically polished after the holes were drilled. Second, the chemical polishing process does not appear to adversely affect the fatigue life. Third, the chemical polishing process will produce a stress-state adjacent to the hole that has insignificant machining residual stresses.

Perceived needs for different components in a rehabilitation program among cancer survivors with chronic fatigue compared to survivors without chronic fatigue.

PubMed

Gjerset, Gunhild M; Loge, Jon H; Kiserud, Cecilie E; Fosså, Sophie D; Gudbergsson, Sævar B; Oldervoll, Line M; Wisløff, Torbjørn; Thorsen, Lene

2017-02-01

Knowledge about the user' needs is important to develop targeted rehabilitation for cancer patients with chronic fatigue (CF). The aims of the study were to examine prevalence of CF in cancer survivors attending an one-week inpatient educational program (IEP) and to identify characteristics of those with CF. Further to examine the perceived needs for different components in a rehabilitation program, need of complex rehabilitation (at least two components) and aspects of health-related quality of life (HRQoL) among survivors with CF versus those without CF. Cancer survivors ≥18 years, diagnosed with different types of cancer within the last 10 years and attending a one-week IEP were invited to this cross-sectional study. CF was assessed by the Fatigue Questionnaire, perceived needs by asking a question about needs for different components in a rehabilitation program and HRQoL was assessed by The Medical Outcomes Study Short Form 36. Of 564 participants, 45% reported CF. Breast cancer, mixed cancer types (including small groups with different cancer types) and comorbidities increased the risk for having CF. Compared to participants without CF, the participants with CF reported more frequently need for physical training (86% vs. 65%, p < 0.001), physiotherapy (71% vs. 55%, p < 0.001) and nutrition counseling (68% vs. 53%, p = 0.001). Among participants with CF, 75% reported need for three or more components whereas 54% reported need for the same number of components among those without CF (p < 0.001). Almost half of the cancer survivors attending the IEP had CF. Physical training, physiotherapy and nutrition counseling were the most frequently reported needs and significantly more often observed in participants with CF than without CF. A higher percentage of those with CF reported need for a complex rehabilitation compared to those without CF. More research is necessary to obtain more knowledge to further make targeted programs to better match cancer survivors' needs.

Review of sonic fatigue technology

NASA Technical Reports Server (NTRS)

Clarkson, B. L.

1994-01-01

From the early-1960s until the mid-1980s, there was very little theoretical development for sonic fatigue prediction. Design nomographs based on simple theoretical models and results of specially designed tests were developed for most common aircraft structures. The use of advanced composites in the 1980s, however, generated an increased interest in development of more sophisticated theoretical models because of the possibilities for a much wider range of structural designs. The purpose of this report is to review sonic fatigue technology and, in particular, to assess recent developments. It also suggests a plan for a coordinated program of theoretical and experimental work to meet the anticipated needs of future aerospace vehicles.

No Fatigue Effect on Blink Rate

NASA Technical Reports Server (NTRS)

Kim, W.; Zangemeister, W.; Stark, L.

1984-01-01

Blink rate is reported to vary dependent upon ongoing task performance, perceptual, attentional and cognitive factors, and fatigue. Five levels of task difficulty were operationally defined and task performance as lines read aloud per minute were measured. A single noninvasive infrared TV eyetracker was modified to measure blinking and an on-line computer program identified and counted blinks while the subject performed the tasks. Blink rate decreased by 50% when either task performance increased (fast reading) or visual difficulty increased (blurred text); blink rate increased greatly during rest breaks. There was no change in blink rate during one hour experiments even though subjects complained of severe fatigue.

"They Sweat for Science": The Harvard Fatigue Laboratory and Self-Experimentation in American Exercise Physiology.

PubMed

Johnson, Andi

2015-08-01

In many scientific fields, the practice of self-experimentation waned over the course of the twentieth century. For exercise physiologists working today, however, the practice of self-experimentation is alive and well. This paper considers the role of the Harvard Fatigue Laboratory and its scientific director, D. Bruce Dill, in legitimizing the practice of self-experimentation in exercise physiology. Descriptions of self-experimentation are drawn from papers published by members of the Harvard Fatigue Lab. Attention is paid to the ethical and practical justifications for self-experimentation in both the lab and the field. Born out of the practical, immediate demands of fatigue protocols, self-experimentation performed the long-term, epistemological function of uniting physiological data across time and space, enabling researchers to contribute to a general human biology program.

A Pragmatic Evaluation of the National Cancer Institute Physician Data Query (PDQ)®-Based Brief Counseling on Cancer-Related Fatigue among Patients Undergoing Radiation Therapy

PubMed Central

Bauml, Joshua; Xie, Sharon X; Penn, Courtney; Desai, Krupali; Dong, Kimberly W; Bruner, Deborah Watkins; Vapiwala, Neha; Mao, Jun James

2018-01-01

Purpose Cancer-Related Fatigue (CRF) negatively affects quality of life among cancer patients. This study seeks to evaluate the outcome and patient receptiveness of a brief counseling program based on National Cancer Institute (NCI) PDQ® information to manage CRF when integrated into Radiation Therapy (RT). Methods We conducted a prospective cohort study among patients undergoing non-palliative RT. Patients with stage I–III tumors and with Karnofsky score 60 or better were given a ten-minute behavioral counseling session during the first two weeks of RT. The Brief Fatigue Inventory (BFI) was administered at baseline/end of RT. Results Of 93 patients enrolled, 89% found the counseling useful and practical. By the end of RT, 59% reported increased exercise, 41.6% sought nutrition counseling, 72.7% prioritized daily activities, 74.4% took daytime naps, and 70.5% talked with other cancer patients. Regarding counseling, patients who had received chemotherapy prior to RT had no change in fatigue (−0.2), those who received RT alone had mild increase in fatigue (0.7, p=0.02), and those who received concurrent chemotherapy experienced a substantial increase in fatigue (3.0 to 5.2, p=0.05). Higher baseline fatigue and receipt of chemotherapy were predictive of worsened fatigue in a multivariate model (both p<0.01). Conclusion Our data suggests that brief behavioral counseling based on NCI guidelines is well accepted by patients showing an uptake in many activities to cope with CRF. Those who receive concurrent chemotherapy and with higher baseline fatigue are at risk for worsening fatigue despite of guideline-based therapy. PMID:29479490

Vehicle Exposure and Spinal Musculature Fatigue in Military Warfighters: A Meta-Analysis.

PubMed

Kollock, Roger O; Games, Kenneth E; Wilson, Alan E; Sefton, JoEllen M

2016-11-01

 Spinal musculature fatigue from vehicle exposure may place warfighters at risk for spinal injuries and pain. Research on the relationship between vehicle exposure and spinal musculature fatigue is conflicting. A better understanding of the effect of military duty on musculoskeletal function is needed before sports medicine teams can develop injury-prevention programs.  To determine if the literature supports a definite effect of vehicle exposure on spinal musculature fatigue.  We searched the MEDLINE, Military & Government Collection (EBSCO), National Institute for Occupational Safety and Health Technical Information Center, PubMed, and Web of Science databases for articles published between January 1990 and September 2015.  To be included, a study required a clear sampling method, preexposure and postexposure assessments of fatigue, a defined objective measurement of fatigue, a defined exposure time, and a study goal of exposing participants to forces related to vehicle exposure.  Sample size, mean preexposure and postexposure measures of fatigue, vehicle type, and exposure time.  Six studies met the inclusion criteria. We used the Scottish Intercollegiate Guidelines Network algorithm to determine the appropriate tool for quality appraisal of each article. Unweighted random-effects model meta-analyses were conducted, and a natural log response ratio was used as the effect metric. The overall meta-analysis demonstrated that vehicle exposure increased fatigue of the spinal musculature (P = .03; natural log response ratio = -0.22, 95% confidence interval = -0.42, -0.02). Using the spinal region as a moderator, we observed that vehicle ride exposure significantly increased fatigue at the lumbar musculature (P = .02; natural log response ratio = -0.27, 95% confidence interval = -0.50, -0.04) but not at the cervical or thoracic region.  Vehicle exposure increased fatigue at the lumbar region.

Vehicle Exposure and Spinal Musculature Fatigue in Military Warfighters: A Meta-Analysis

PubMed Central

Kollock, Roger O.; Games, Kenneth E.; Wilson, Alan E.; Sefton, JoEllen M.

2016-01-01

Context: Spinal musculature fatigue from vehicle exposure may place warfighters at risk for spinal injuries and pain. Research on the relationship between vehicle exposure and spinal musculature fatigue is conflicting. A better understanding of the effect of military duty on musculoskeletal function is needed before sports medicine teams can develop injury-prevention programs. Objective: To determine if the literature supports a definite effect of vehicle exposure on spinal musculature fatigue. Data Sources: We searched the MEDLINE, Military & Government Collection (EBSCO), National Institute for Occupational Safety and Health Technical Information Center, PubMed, and Web of Science databases for articles published between January 1990 and September 2015. Study Selection: To be included, a study required a clear sampling method, preexposure and postexposure assessments of fatigue, a defined objective measurement of fatigue, a defined exposure time, and a study goal of exposing participants to forces related to vehicle exposure. Data Extraction: Sample size, mean preexposure and postexposure measures of fatigue, vehicle type, and exposure time. Data Synthesis: Six studies met the inclusion criteria. We used the Scottish Intercollegiate Guidelines Network algorithm to determine the appropriate tool for quality appraisal of each article. Unweighted random-effects model meta-analyses were conducted, and a natural log response ratio was used as the effect metric. The overall meta-analysis demonstrated that vehicle exposure increased fatigue of the spinal musculature (P = .03; natural log response ratio = −0.22, 95% confidence interval = −0.42, −0.02). Using the spinal region as a moderator, we observed that vehicle ride exposure significantly increased fatigue at the lumbar musculature (P = .02; natural log response ratio = −0.27, 95% confidence interval = −0.50, −0.04) but not at the cervical or thoracic region. Conclusions: Vehicle exposure increased fatigue at the lumbar region. PMID:28068167

Quality of Life and Its Predictors Among Children and Adolescents With Cancer.

PubMed

Pan, Hsien-Ting; Wu, Li-Min; Wen, Shu-Hui

Quality of life (QoL) increasingly is being assessed in pediatric patients with cancer. However, only a few studies focused on QoL predictors during and after treatment for pediatric patients with cancer. The aims of this study were to (1) assess differences of QoL, distress behavior, and fatigue among children and adolescents; (2) examine the relationship of distress behaviors, fatigue, and a variety of demographic factors to QoL; and (3) identify QoL predictors. A cross-sectional descriptive study involving 150 participants treated between 2012 and 2014 was conducted. All participants were given a diagnosis of cancer, ranged in age from 7 to 18 years, and had no developmental delay or mental illness. Three instruments including Pediatric Quality of Life, Distress Behaviors, and Multidimensional Fatigue Scale were administered. Adolescents aged 16 to 18 years reported lower school functioning and experienced more general and sleep/rest fatigue. Fatigue and distress behaviors were associated with a poorer QoL. Diagnosis at a younger age, greater time since diagnosis, and family structure were associated with a better QoL. General fatigue, relationship distress, family structure, and time since diagnosis were significant predictors of QoL, accounting for 64% of the total variance. Factors associated with a poorer QoL included fatigue, distress behaviors, and diagnosis at an older age. Less general fatigue and relationship distress, greater time since diagnosis, and living in nuclear family predicted a better QoL. Routinely evaluating fatigue and school functioning in pediatric patients with cancer is warranted, as well as developing educational programs to enhance the management of fatigue and relationship issues, especially for those who were given a diagnosis recently or for late adolescents.

Psychometric properties of the Fatigue Severity Scale in obese patients

PubMed Central

2013-01-01

Background The aim of this study was to examine the psychometric properties of the Fatigue Severity Scale (FSS) to verify whether this instrument is a valid tool to measure fatigue in obese patients, and to examine the prevalence of fatigue in obese patients. Methods Before and after a three-week residential multidisciplinary integrated weight reduction program, 220 patients were asked to fill in the questionnaires: FSS, Profile of Mood States (Fatigue-Inertia subscale, POMS-Fatigue, and Vigor-Activity subscale, POMS-Vigor), and the Obesity-Related Well-Being (ORWELL-97). A subsample of 50 patients completed the questionnaire within two days. Results The prevalence of fatigue using a cut-off value of 4 for the FSS score was 59%. Correlations were found between FSS and POMS-Fatigue and -Vigor scores (r = 0.58 and 0.53, respectively). A relation was also found between FSS and ORWELL97 (r = 0.52, 0.42 to 0.61). From the factorial analysis only 1 factor was extracted explaining 63% of variance, with factor loading values ranging from 0.71 (item 7) to 0.87 (item 6). Intraclass Correlation Coefficient was 0.89 (0.82 to 0.94), while the agreement as measured using the Standard Error of Measurement was 0.43 (0.36 to 0.54) corresponding to 13% (11 to 17%). Cronbach’s alpha values ranged from 0.94 to 0.93. The internal responsiveness of FSS was comparable to the ORWELL97 (Standardized Response Mean = 0.50 and 0.44, respectively). Conclusions Fatigue is an important and frequent symptom in obese patients and therefore should be routinely assessed in both research and clinical practice. This can be achieved using the FSS, which is a short, simple, valid and reliable tool for assessing and quantifying fatigue in obese patients. PMID:23496886

Supervised exercise reduces cancer-related fatigue: a systematic review.

PubMed

Meneses-Echávez, José F; González-Jiménez, Emilio; Ramírez-Vélez, Robinson

2015-01-01

Does supervised physical activity reduce cancer-related fatigue? Systematic review with meta-analysis of randomised trials. People diagnosed with any type of cancer, without restriction to a particular stage of diagnosis or treatment. Supervised physical activity interventions (eg, aerobic, resistance and stretching exercise), defined as any planned or structured body movement causing an increase in energy expenditure, designed to maintain or enhance health-related outcomes, and performed with systematic frequency, intensity and duration. The primary outcome measure was fatigue. Secondary outcomes were physical and functional wellbeing assessed using the Functional Assessment of Cancer Therapy Fatigue Scale, European Organisation for Research and Treatment of Cancer Quality of Life QUESTIONnaire, Piper Fatigue Scale, Schwartz Cancer Fatigue Scale and the Multidimensional Fatigue Inventory. Methodological quality, including risk of bias of the studies, was evaluated using the PEDro Scale. Eleven studies involving 1530 participants were included in the review. The assessment of quality showed a mean score of 6.5 (SD 1.1), indicating a low overall risk of bias. The pooled effect on fatigue, calculated as a standardised mean difference (SMD) using a random-effects model, was -1.69 (95% CI -2.99 to -0.39). Beneficial reductions in fatigue were also found with combined aerobic and resistance training with supervision (SMD=-0.41, 95% CI -0.70 to -0.13) and with combined aerobic, resistance and stretching training with supervision (SMD=-0.67, 95% CI -1.17 to -0.17). Supervised physical activity interventions reduce cancer-related fatigue. These findings suggest that combined aerobic and resistance exercise regimens with or without stretching should be included as part of rehabilitation programs for people who have been diagnosed with cancer. PROSPERO CRD42013005803. Copyright © 2014 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

A two-year follow-up case of chronic fatigue syndrome: substantial improvement in personality following a yoga-based lifestyle intervention.

PubMed

Yadav, Raj Kumar; Sarvottam, Kumar; Magan, Dipti; Yadav, Rashmi

2015-04-01

Chronic Fatigue Syndrome (CFS) is characterized by excessive fatigue after minimal physical or mental exertion, muscle and joint pain, poor concentration, dizziness, and sleep disturbances. We report here the effect of a yoga-based lifestyle intervention in a 30-year old male patient with a documented diagnosis of CFS with compromised quality of life (QoL) and altered personality. The patient initially attended a short-term yoga-based lifestyle intervention program that consisted of yoga-postures, breathing exercises (pranayama), meditation, group discussions, and individualized advice on stress management, diet and physical activity besides group support. Thereafter, patient attended 5 more such programs. There was a notable and consistent improvement in his clinical profile, positive aspects of personality and subjective well-being, and reduction in anxiety following this yoga-based lifestyle intervention. Overall, the results suggest that lifestyle intervention may improve clinical condition and personality in patients with CFS.

Results of inphase axial-torsional fatigue experiments on 304 stainless steel

NASA Technical Reports Server (NTRS)

Bonacuse, Peter J.; Kalluri, Sreeramesh

1989-01-01

A series of axial-torsional, inphase, strain-controlled, low-cycle fatigue tests were performed at room temperature on tubular specimens of 304 stainless steel. The program was conducted in cooperation with the task group on multiaxial fatigue research of ASTM committee E-09. The objective was to quantify the variability in multiaxial test results among several laboratories. Only included is data which was generated at the NASA Lewis Research Center's High Temperature Fatigue and Structures Laboratory. The experimental equipment and procedures used are described. The tubular specimens were polished on the outer surface to aid in the use of a cellulose film surface replication technique for crack detection. However, cracking initiated predominantly on the internal surface for all specimens. Honing of the bore of the tubular specimens lessened but did not entirely eliminate this problem. The observed fatigue lives are compared with lives calculated from three multiaxial life models. Constants for the life prediction models were obtained from uniaxial and torsional tests performed on the same heat of material. The observed fatigue lives agreed with calculated lives to within a factor of two for all but one of the life prediction models.

Analysis of Crew Fatigue in AIA Guantanamo Bay Aviation Accident

NASA Technical Reports Server (NTRS)

Rosekind, Mark R.; Gregory, Kevin B.; Miller, Donna L.; Co, Elizabeth L.; Lebacqz, J. Victor; Statler, Irving C. (Technical Monitor)

1994-01-01

Flight operations can engender fatigue, which can affect flight crew performance, vigilance, and mood. The National Transportation Safety Board (NTSB) requested the NASA Fatigue Countermeasures Program to analyze crew fatigue factors in an aviation accident that occurred at Guantanamo Bay, Cuba. There are specific fatigue factors that can be considered in such investigations: cumulative sleep loss, continuous hours of wakefulness prior to the incident or accident, and the time of day at which the accident occurred. Data from the NTSB Human Performance Investigator's Factual Report, the Operations Group Chairman's Factual Report, and the Flight 808 Crew Statements were analyzed, using conservative estimates and averages to reconcile discrepancies among the sources. Analysis of these data determined the following: the entire crew displayed cumulative sleep loss, operated during an extended period of continuous wakefulness, and obtained sleep at times in opposition to the circadian disposition for sleep, and that the accident occurred in the afternoon window of physiological sleepiness. In addition to these findings, evidence that fatigue affected performance was suggested by the cockpit voice recorder (CVR) transcript as well as in the captain's testimony. Examples from the CVR showed degraded decision-making skills, fixation, and slowed responses, all of which can be affected by fatigue; also, the captain testified to feeling "lethargic and indifferent" just prior to the accident. Therefore, the sleep/wake history data supports the hypothesis that fatigue was a factor that affected crewmembers' performance. Furthermore, the examples from the CVR and the captain's testimony support the hypothesis that the fatigue had an impact on specific actions involved in the occurrence of the accident.

Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, Mechanical Fatigue, Creep and Thermal Fatigue Effects

NASA Technical Reports Server (NTRS)

Bast, Callie Corinne Scheidt

1994-01-01

This thesis presents the on-going development of methodology for a probabilistic material strength degradation model. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes four effects that typically reduce lifetime strength: high temperature, mechanical fatigue, creep, and thermal fatigue. Statistical analysis was conducted on experimental Inconel 718 data obtained from the open literature. This analysis provided regression parameters for use as the model's empirical material constants, thus calibrating the model specifically for Inconel 718. Model calibration was carried out for four variables, namely, high temperature, mechanical fatigue, creep, and thermal fatigue. Methodology to estimate standard deviations of these material constants for input into the probabilistic material strength model was developed. Using the current version of PROMISS, entitled PROMISS93, a sensitivity study for the combined effects of mechanical fatigue, creep, and thermal fatigue was performed. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing a combination of mechanical fatigue and high temperature effects by model to the combination by experiment were conducted. Thus, for Inconel 718, the basic model assumption of independence between effects was evaluated. Results from this limited verification study strongly supported this assumption.

Effects of a Training Program Involving Body Cooling on Physical and Cognitive Capacities and Quality of Life in Multiple Sclerosis Patients: A Pilot Study.

PubMed

Gonzales, Benoit; Chopard, Gilles; Charry, Benjamin; Berger, Eric; Tripard, Julien; Magnin, Eloi; Groslambert, Alain

2017-01-01

Two methods using exercise and body cooling could influence the well-being of patients with multiple sclerosis (PwMS). The aim of this study was to determine whether wearing a cooling vest during a physical training program could increase the cognitive and physical capacities and quality of life in PwMS. Eighteen PwMS (49.6 ± 8 years; Expanded Disability Status Score 5.0 ± 1.0) were randomly assigned to a cooling or control group. PwMS underwent a 7-week physical training program. In the cooling group, PwMS wore a cooling vest during each training session, whereas in the control group, PwMS wore a cotton T-shirt. Before and after the training program, both groups completed the Isaacs Set Test (IST), Trail Making Test A-B (TMT A-B), SEP-59, Multidimensional Fatigue Inventory and performed a 6-minute walk test (6MWT). The cooling group showed significantly (p < 0.05) improved performance for IST, TMT A and 6MWT. Their emotional well-being and cognitive functions investigated in SEP-59 were significantly (p < 0.05) improved, and general and physical fatigue significantly (p < 0.05) decreased. This physical training program combined with a cooling strategy could have a significant positive influence on both cognitive and physical performances, perceived fatigue and emotional well-being in heat-sensitive PwMS. © 2017 S. Karger AG, Basel.

Individualized Biomathematical Modeling of Fatigue and Performance

DTIC Science & Technology

2008-05-29

NUMBER Fatigue and Performance 5b. GRANT NUMBER FA9550-06-1-0055 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Hans P.A. Van Dongen, Ph.D...5d. PROJECT NUMBER (Principal Investigator) 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...Sleep and Performance Research Center 8. PERFORMING ORGANIZATION REPORT NUMBER Washington State University, Spokane P.O. Box 1495 Spokane, WA

The Role of Microtexture on Fatigue Lifetime Variability and Crack Initiation Mechanisms (Preprint)

DTIC Science & Technology

2011-10-01

October 2011 4 . TITLE AND SUBTITLE THE ROLE OF MICROTEXTURE OF FATIGUE LIFETIME VARIABILITY AND CRACK INITIATION MECHANISMS (PREPRINT) 5a...CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6 . AUTHOR(S) Christopher J. Szczepanski (Universal Technology...Preprint journal article to be submitted to Titanium 2011 World Conference. This document contains color. 14. ABSTRACT Commercial titanium alloys

Flight Attendant Fatigue. Part IV. Analysis of Incident Reports

DTIC Science & Technology

2009-12-01

Flight Attendant Fatigue, Part IV: Analysis of Incident Reports Kali Holcomb Katrina Avers Lena Dobbins Joy Banks Lauren Blackwell Thomas Nesthus...Incident Reports 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Holcomb K, Avers K, Dobbins L, Banks J...observed by erC members of the flight attendant ASAP programs, a survey was developed. Surveys were distributed via e -Mail to 23 participants for

Randomized Controlled Trial to Examine the Impact of Aquatic Exercise Training on Functional Capacity, Balance, and Perceptions of Fatigue in Female Patients With Multiple Sclerosis.

PubMed

Kargarfard, Mehdi; Shariat, Ardalan; Ingle, Lee; Cleland, Joshua A; Kargarfard, Mina

2018-02-01

To assess the effects of an 8-week aquatic exercise training program on functional capacity, balance, and perceptions of fatigue in women with multiple sclerosis (MS). Randomized controlled design. Referral center of an MS society. Women (N=32; mean age ± SD, 36.4±8.2y) with diagnosed relapsing-remitting MS. After undergoing baseline testing by a neurologist, participants were allocated to either an intervention (aquatic training program, n=17) or a control group (n=15). The intervention consisted of an 8-week aquatic training program (3 supervised training sessions per week; session duration, 45-60min; 50%-75% estimated maximum heart rate). Six-minute walk test (6-MWT), balance (Berg Balance Scale [BBS]), and perceptions of fatigue (Modified Fatigue Impact Scale; [MFIS]) at baseline and after the 8-week intervention. Differences over time between the experimental and control groups were assessed by a 2×2 (group by time) repeated-measures analysis of variance. Thirty-two women completed the 8-week aquatic training intervention (experimental group, n=17; control group, n=15). All outcome measures improved in the experimental group: 6-MWT performance (pretest mean ± SD, 451±58m; posttest mean ± SD, 503±57m; P<.001); BBS (pretest mean ± SD, 53.59±1.70; posttest mean ± SD, 55.18±1.18; P<.001), and MFIS (pretest mean ± SD, 43.1±14.6; posttest mean ± SD, 32.8±5.9; P<.01). A significant group-by-time interaction was evident between the experimental and control groups for 6-MWT (P<.001, partial eta 2 [η p 2 ]=.551), BBS (P<.001, η p 2 =.423), and MFIS (P<.001, η p 2 =.679). Aquatic exercise training improved functional capacity, balance, and perceptions of fatigue in women with MS. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effect of job maintenance training program for employees with chronic disease - a randomized controlled trial on self-efficacy, job satisfaction, and fatigue.

PubMed

Varekamp, Inge; Verbeek, Jos H; de Boer, Angela; van Dijk, Frank J H

2011-07-01

Employees with a chronic physical condition may be hampered in job performance due to physical or cognitive limitations, pain, fatigue, psychosocial barriers, or because medical treatment interferes with work. This study investigates the effect of a group-training program aimed at job maintenance. Essential elements of the program are exploration of work-related problems, communication at the workplace, and the development and implementation of solutions. Participants with chronic physical diseases were randomly assigned to the intervention (N=64) or the control group (N=58). Participants were eligible for the study if they had a chronic physical disease, paid employment, experienced work-related problems, and were not on long-term 100% sick leave. Primary outcome measures were self-efficacy in solving work- and disease-related problems (14-70), job dissatisfaction (0-100), fatigue (20-140) and job maintenance measured at 4-, 8-, 12- and 24-month follow-up. We used GLM repeated measures for the analysis. After 24 months, loss to follow-up was 5.7% (7/122). Self-efficacy increased and fatigue decreased significantly more in the experimental than the control group [10 versus 4 points (P=0.000) and 19 versus 8 points (P=0.032), respectively]. Job satisfaction increased more in the experimental group but not significantly [6 versus 0 points (P=0.698)]. Job maintenance was 87% in the experimental and 91% in the control group, which was not a significant difference. Many participants in the control group also undertook actions to solve work-related problems. Empowerment training increases self-efficacy and helps to reduce fatigue complaints, which in the long term could lead to more job maintenance. Better understanding of ways to deal with work-related problems is needed to develop more efficient support for employees with a chronic disease.

High temperature fatigue behavior of Haynes 188

NASA Technical Reports Server (NTRS)

Halford, Gary R.; Saltsman, James F.; Kalluri, Sreeramesh

1988-01-01

The high temperature, creep-fatigue behavior of Haynes 188 was investigated as an element in a broader thermomechanical fatigue life prediction model development program at the NASA-Lewis. The models are still in the development stage, but the data that were generated possess intrinsic value on their own. Results generated to date is reported. Data were generated to characterize isothermal low cycle fatigue resistance at temperatures of 316, 704, and 927 C with cyclic failure lives ranging from 10 to more than 20,000. These results follow trends that would be predicted from a knowledge of tensile properties, i.e., as the tensile ductility varies with temperature, so varies the cyclic inelastic straining capacity. Likewise, as the tensile strength decreases, so does the high cyclic fatigue resistance. A few two-minute hold-time cycles at peak compressive strain were included in tests at 760 C. These results were obtained in support of a redesign effort for the Orbital Maneuverable System engine. No detrimental effects on cyclic life were noted despite the added exposure time for creep and oxidation. Finally, a series of simulated thermal fatigue tests, referred to as bithermal fatigue tests, were conducted using 316 C as the minimum and 760 C as the maximum temperature. Only out-of-phase bithermal tests were conducted to date. These test results are intended for use as input to a more general thermomechanical fatigue life prediction model based on the concepts of the total strain version of Strainrange Partitioning.

Determinants of seafarers' fatigue: a systematic review and quality assessment.

PubMed

Dohrmann, Solveig Boeggild; Leppin, Anja

2017-01-01

Fatigue jeopardizes seafarer's health and safety. Thus, knowledge on determinants of fatigue is of great importance to facilitate its prevention. However, a systematic analysis and quality assessment of all empirical evidence specifically for fatigue are still lacking. The aim of the present article was therefore to systematically detect, analyze and assess the quality of this evidence. Systematic searches in ten databases were performed. Searches considered articles published in scholarly journals from 1980 to April 15, 2016. Nineteen out of 98 eligible studies were included in the review. The main reason for exclusion was fatigue not being the outcome variable. Most evidence was available for work time-related factors suggesting that working nights was most fatiguing, that fatigue levels were higher toward the end of watch or shift, and that the 6-h on-6-h off watch system was the most fatiguing. Specific work demands and particularly the psychosocial work environment have received little attention, but preliminary evidence suggests that stress may be an important factor. A majority of 12 studies were evaluated as potentially having a high risk of bias. Realistic countermeasures ought to be established, e.g., in terms of shared or split night shifts. As internal as well as external validity of many study findings was limited, the range of factors investigated was insufficient and few studies investigated more complex interactions between different factors, knowledge derived from studies of high methodological quality investigating different factors, including psychosocial work environments, are needed to support future preventive programs.

Examination of Broad Symptom Improvement Resulting From Mindfulness-Based Stress Reduction in Breast Cancer Survivors: A Randomized Controlled Trial

PubMed Central

Reich, Richard R.; Paterson, Carly L.; Ramesar, Sophia; Park, Jong Y.; Alinat, Carissa; Johnson-Mallard, Versie; Moscoso, Manolete; Budhrani-Shani, Pinky; Miladinovic, Branko; Jacobsen, Paul B.; Cox, Charles E.; Goodman, Matthew; Kip, Kevin E.

2016-01-01

Purpose The purpose of this randomized trial was to evaluate the efficacy of the Mindfulness-Based Stress Reduction for Breast Cancer (MBSR[BC]) program in improving psychological and physical symptoms and quality of life among breast cancer survivors (BCSs) who completed treatment. Outcomes were assessed immediately after 6 weeks of MBSR(BC) training and 6 weeks later to test efficacy over an extended timeframe. Patients and Methods A total of 322 BCSs were randomly assigned to either a 6-week MBSR(BC) program (n = 155) or a usual care group (n = 167). Psychological (depression, anxiety, stress, and fear of recurrence) and physical symptoms (fatigue and pain) and quality of life (as related to health) were assessed at baseline and at 6 and 12 weeks. Linear mixed models were used to assess MBSR(BC) effects over time, and participant characteristics at baseline were also tested as moderators of MBSR(BC) effects. Results Results demonstrated extended improvement for the MBSR(BC) group compared with usual care in both psychological symptoms of anxiety, fear of recurrence overall, and fear of recurrence problems and physical symptoms of fatigue severity and fatigue interference (P < .01). Overall effect sizes were largest for fear of recurrence problems (d = 0.35) and fatigue severity (d = 0.27). Moderation effects showed BCSs with the highest levels of stress at baseline experienced the greatest benefit from MBSR(BC). Conclusion The MBSR(BC) program significantly improved a broad range of symptoms among BCSs up to 6 weeks after MBSR(BC) training, with generally small to moderate overall effect sizes. PMID:27247219

Fatigue mitigation with SleepTrackTXT2 in air medical emergency care systems: study protocol for a randomized controlled trial.

PubMed

Patterson, P Daniel; Moore, Charity G; Guyette, Frank X; Doman, Jack M; Sequeira, Denisse; Werman, Howard A; Swanson, Doug; Hostler, David; Lynch, Joshua; Russo, Lindsey; Hines, Linda; Swecker, Karen; Runyon, Michael S; Buysse, Daniel J

2017-06-05

Most air medical Emergency Medical Services (EMS) clinicians work extended duration shifts, and more than 50% report inadequate sleep, poor sleep quality, and/or poor recovery between shifts. The SleepTrackTXT pilot trial (ClinicalTrials.gov, NCT02063737) showed that use of mobile phone text messages could impact EMS clinician self-reported fatigue and sleepiness during long duration shifts. The purpose of the SleepTrackTXT2 trial is to leverage lessons learned from the first SleepTrackTXT study and test an enhanced intervention targeting air medical EMS clinicians. We will conduct a multi-site randomized trial with a sample of adult EMS clinicians recruited from four air medical EMS systems located in the midwest, northeastern, and southern USA. Participants will be allocated to one of two possible arms for a 4-month (120-day) study period. The intervention arm will involve text-message assessments of sleepiness, fatigue, and difficulty concentrating at the beginning, every 4 hours during, and at the end of scheduled shifts. Participants reporting high levels of sleepiness, fatigue, or difficulty with concentration will receive one of nine randomly selected intervention messages to promote behavior change during shift work to improve alertness. Intervention participants will receive a text-message report on Friday of each week that shows their sleep debt over the previous 7 days followed by a text message to promote paying back sleep debt recovery when feasible. Participants in the control group receive text messages that only include assessments. Both arms will receive text-message assessments of perceived recovery since last shift, sleepiness, fatigue, or difficulty with concentration at noon (1200 hours) on days between scheduled shifts (off-duty days). We have two aims for this study: (1) to determine the short-term impact of the enhanced SleepTrackTXT2 intervention on air medical clinician fatigue reported in real time during and at the end of shift work, and (2) to determine the long-term impact of the SleepTrackTXT2 intervention on sleep quality and sleep health indicators including hours of sleep and recovery between shift work. The SleepTrackTXT2 trial may provide evidence of real-world effectiveness that would support widespread expansion of fatigue mitigation interventions in emergency care clinician shift workers. The trial may specifically support use of real-time assessments and interventions delivered via mobile technology such as text messaging. ClinicalTrials.gov, NCT02783027 . Registered on 23 May 2016.

Evidence of small-fiber polyneuropathy in unexplained, juvenile-onset, widespread pain syndromes.

PubMed

Oaklander, Anne Louise; Klein, Max M

2013-04-01

We tested the hypothesis that acquired small-fiber polyneuropathy (SFPN), previously uncharacterized in children, contributes to unexplained pediatric widespread pain syndromes. Forty-one consecutive patients evaluated for unexplained widespread pain beginning before age 21 had medical records comprehensively analyzed regarding objective diagnostic testing for SFPN (neurodiagnostic skin biopsy, nerve biopsy, and autonomic function testing), plus histories, symptoms, signs, other tests, and treatments. Healthy, demographically matched volunteers provided normal controls for SFPN tests. Age at illness onset averaged 12.3 ± 5.7 years; 73% among this poly-ethnic sample were female (P = .001). Sixty-eight percent were chronically disabled, and 68% had hospitalizations. Objective testing diagnosed definite SFPN in 59%, probable SFPN in 17%, and possible SFPN in 22%. Only 1 of 41 had entirely normal SFPN test results. Ninety-eight percent of patients had other somatic complaints consistent with SFPN dysautonomia (90% cardiovascular, 82% gastrointestinal, and 34% urologic), 83% reported chronic fatigue, and 63% had chronic headache. Neurologic examinations identified reduced sensation in 68% and vasomotor abnormalities in 55%, including 23% with erythromelalgia. Exhaustive investigations for SFPN causality identified only history of autoimmune illnesses in 33% and serologic markers of disordered immunity in 89%. Treatment with corticosteroids and/or intravenous immune globulin objectively and subjectively benefited 80% of patients (12/15). More than half among a large series of patients with childhood-onset, unexplained chronic widespread pain met rigorous, multitest, diagnostic criteria for SFPN, which extends the age range of acquired SFPN into early childhood. Some cases appeared immune-mediated and improved with immunomodulatory therapies.

Evidence of Small-Fiber Polyneuropathy in Unexplained, Juvenile-Onset, Widespread Pain Syndromes

PubMed Central

Klein, Max M.

2013-01-01

OBJECTIVE: We tested the hypothesis that acquired small-fiber polyneuropathy (SFPN), previously uncharacterized in children, contributes to unexplained pediatric widespread pain syndromes. METHODS: Forty-one consecutive patients evaluated for unexplained widespread pain beginning before age 21 had medical records comprehensively analyzed regarding objective diagnostic testing for SFPN (neurodiagnostic skin biopsy, nerve biopsy, and autonomic function testing), plus histories, symptoms, signs, other tests, and treatments. Healthy, demographically matched volunteers provided normal controls for SFPN tests. RESULTS: Age at illness onset averaged 12.3 ± 5.7 years; 73% among this poly-ethnic sample were female (P = .001). Sixty-eight percent were chronically disabled, and 68% had hospitalizations. Objective testing diagnosed definite SFPN in 59%, probable SFPN in 17%, and possible SFPN in 22%. Only 1 of 41 had entirely normal SFPN test results. Ninety-eight percent of patients had other somatic complaints consistent with SFPN dysautonomia (90% cardiovascular, 82% gastrointestinal, and 34% urologic), 83% reported chronic fatigue, and 63% had chronic headache. Neurologic examinations identified reduced sensation in 68% and vasomotor abnormalities in 55%, including 23% with erythromelalgia. Exhaustive investigations for SFPN causality identified only history of autoimmune illnesses in 33% and serologic markers of disordered immunity in 89%. Treatment with corticosteroids and/or intravenous immune globulin objectively and subjectively benefited 80% of patients (12/15). CONCLUSIONS: More than half among a large series of patients with childhood-onset, unexplained chronic widespread pain met rigorous, multitest, diagnostic criteria for SFPN, which extends the age range of acquired SFPN into early childhood. Some cases appeared immune-mediated and improved with immunomodulatory therapies. PMID:23478869

Central and peripheral fatigue development in the shoulder muscle with obesity during an isometric endurance task.

PubMed

Pajoutan, Mojdeh; Ghesmaty Sangachin, Mahboobeh; Cavuoto, Lora A

2017-07-21

Fatigue increases the likelihood of developing work-related musculoskeletal disorders and injury. Due to the physiological and neuromuscular changes that accompany obesity, it may alter the fatigue development mechanism and exacerbate injury risk. The upper extremities have the highest incidence rates for work-related musculoskeletal disorders. Therefore, the goals of this study were to investigate the effect of obesity on central vs. peripheral fatigue as well as on the physical signs of fatigue on the middle deltoid muscle. A measure of central activation ratio was used to quantify central fatigue by considering the increment in the torque output by superimposed twitch relative to its corresponding maximum voluntary contraction. For this purpose, electrical stimulation was delivered at the middle deltoid muscles of 22 non-obese (18 < body mass index (BMI) < 25 kg/m 2 ) and 17 obese (30 < BMI < 40 kg/m 2 ) individuals aged 18-32 years old. Participants completed superimposed maximum voluntary isometric contractions of shoulder abduction before and after a sustained isometric fatiguing task at either 30 or 60% of the muscle capacity. Differences in endurance time, torque fluctuation, torque loss, and muscle activity measured by an electromyography sensor were also investigated. A greater reduction of voluntary activation of motor units (p = 0.001) with fatigue was observed for individuals who are obese. Contrary to the effect of obesity on central fatigue, a trend toward reduced peripheral fatigue (p = 0.06) was observed for the obese group compared to the non-obese group. On average, a 14% higher rate of torque loss per second was observed among individuals with obesity in comparison to non-obese participants. The observed greater contribution of central fatigue during the sustained endurance tasks suggests that among young healthy obese individuals, the faster fatigue development with obesity, commonly reported in the literature, is most likely due to the central elements rather than the peripheral factors. This finding has implications for fatigue prevention programs during sustained exertions and can help to develop training, work, and rest schedules considering obesity.

Association Between Sleep and Productivity Loss Among 598 676 Employees From Multiple Industries.

PubMed

Gingerich, Stefan B; Seaverson, Erin L D; Anderson, David R

2018-05-01

To examine the relationship between sleep habits and employee productivity. Cross-sectional health risk assessment analysis. Employer-sponsored health and well-being programs. A total of 598 676 employed adults from multiple industries. Self-reported average hours of sleep, fatigue, absence days, and presenteeism. Bivariate analyses to assess the relationships between self-reported hours of sleep and self-reported fatigue and mean and median absence and presenteeism. The relationship between sleep hours and both measures of productivity was U-shaped, with the least productivity loss among employees who reported 8 hours of sleep. More daytime fatigue correlated with more absence and presenteeism. Median absence and presenteeism was consistently lower than mean absence and presenteeism, respectively, for the various hours of sleep and levels of fatigue. Organizations looking to expand the value of their investment in employee health and well-being should consider addressing the employee sleep habits that may be negatively impacting productivity.

Scanning Electron Microscope Mapping System Developed for Detecting Surface Defects in Fatigue Specimens

NASA Technical Reports Server (NTRS)

Bonacuse, Peter J.; Kantzos, Peter T.

2002-01-01

An automated two-degree-of-freedom specimen positioning stage has been developed at the NASA Glenn Research Center to map and monitor defects in fatigue specimens. This system expedites the examination of the entire gauge section of fatigue specimens so that defects can be found using scanning electron microscopy (SEM). Translation and rotation stages are driven by microprocessor-based controllers that are, in turn, interfaced to a computer running custom-designed software. This system is currently being used to find and record the location of ceramic inclusions in powder metallurgy materials. The mapped inclusions are periodically examined during interrupted fatigue experiments. The number of cycles to initiate cracks from these inclusions and the rate of growth of initiated cracks can then be quantified. This information is necessary to quantify the effect of this type of defect on the durability of powder metallurgy materials. This system was developed with support of the Ultra Safe program.

Influence of creep damage on the low cycle thermal-mechanical fatigue behavior of two tantalum base alloys

NASA Technical Reports Server (NTRS)

Sheffler, K. D.; Doble, G. S.

1972-01-01

Low cycle fatigue tests have been performed on the tantalum base alloys T-111 and ASTAR 811C with synchronized, independently programmed temperature and strain cycling. The thermal-mechanical cycles applied fell into three basic categories: these were isothermal cycling, in-phase thermal cycling, and out-of-phase thermal cycling. In-phase cycling was defined as tensile deformation associated with high temperature and compressive deformation with low temperature, while out-of-phase thermal cycling was defined as the reverse case. The in-phase thermal cycling had a pronounced detrimental influence on the fatigue life of both alloys, with the life reduction being greater in the solid solution strengthened T-111 alloy than in the carbide strengthened ASTAR 811C alloy. The out-of-phase tests also showed pronounced effects on the fatigue life of both alloys, although not as dramatic.

Probabilistic Composite Design

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1997-01-01

Probabilistic composite design is described in terms of a computational simulation. This simulation tracks probabilistically the composite design evolution from constituent materials, fabrication process, through composite mechanics and structural components. Comparisons with experimental data are provided to illustrate selection of probabilistic design allowables, test methods/specimen guidelines, and identification of in situ versus pristine strength, For example, results show that: in situ fiber tensile strength is 90% of its pristine strength; flat-wise long-tapered specimens are most suitable for setting ply tensile strength allowables: a composite radome can be designed with a reliability of 0.999999; and laminate fatigue exhibits wide-spread scatter at 90% cyclic-stress to static-strength ratios.

Flexural fatigue life prediction of closed hat-section using materially nonlinear axial fatigue characteristics

NASA Technical Reports Server (NTRS)

Razzaq, Zia

1989-01-01

Straight or curved hat-section members are often used as structural stiffeners in aircraft. For instance, they are employed as stiffeners for the dorsal skin as well as in the aerial refueling adjacent area structure in F-106 aircraft. The flanges of the hat-section are connected to the aircraft skin. Thus, the portion of the skin closing the hat-section interacts with the section itself when resisting the stresses due to service loads. The flexural fatigue life of such a closed section is estimated using materially nonlinear axial fatigue characteristics. It should be recognized that when a structural shape is subjected to bending, the fatigue life at the neutral axis is infinity since the normal stresses are zero at that location. Conversely, the fatigue life at the extreme fibers where the normal bending stresses are maximum can be expected to be finite. Thus, different fatigue life estimates can be visualized at various distances from the neural axis. The problem becomes compounded further when significant portions away from the neutral axis are stressed into plastic range. A theoretical analysis of the closed hat-section subjected to flexural cyclic loading is first conducted. The axial fatigue characteristics together with the related axial fatigue life formula and its inverted form given by Manson and Muralidharan are adopted for an aluminum alloy used in aircraft construction. A closed-form expression for predicting the flexural fatigue life is then derived for the closed hat-section including materially nonlinear action. A computer program is written to conduct a study of the variables such as the thicknesses of the hat-section and the skin, and the type of alloy used. The study has provided a fundamental understanding of the flexural fatigue life characteristics of a practical structural component used in aircraft when materially nonlinear action is present.

A home-based exercise program to improve function, fatigue, and sleep quality in patients with Stage IV lung and colorectal cancer: a randomized controlled trial.

PubMed

Cheville, Andrea L; Kollasch, Jenny; Vandenberg, Justin; Shen, Tiffany; Grothey, Axel; Gamble, Gail; Basford, Jeffrey R

2013-05-01

Exercise benefits patients with cancer, but studies of home-based approaches, particularly among those with Stage IV disease, remain small and exploratory. To conduct an adequately powered trial of a home-based exercise intervention that can be facilely integrated into established delivery and reimbursement structures. Sixty-six adults with Stage IV lung or colorectal cancer were randomized, in an eight-week trial, to usual care or incremental walking and home-based strength training. The exercising participants were instructed during a single physiotherapy visit and subsequently exercised four days or more per week; training and step-count goals were advanced during bimonthly telephone calls. The primary outcome measure was mobility assessed with the Ambulatory Post Acute Care Basic Mobility Short Form. Secondary outcomes included ratings of pain and sleep quality as well as the ability to perform daily activities (Ambulatory Post Acute Care Daily Activities Short Form), quality of life (Functional Assessment of Cancer Therapy-General), and fatigue (Functional Assessment of Cancer Therapy-Fatigue). Three participants dropped out and seven died (five in the intervention and two in the control group, P=0.28). At Week 8, the intervention group reported improved mobility (P=0.01), fatigue (P=0.02), and sleep quality (P=0.05) compared with the usual care group, but did not differ on the other measures. A home-based exercise program seems capable of improving the mobility, fatigue, and sleep quality of patients with Stage IV lung and colorectal cancer. Copyright © 2013. Published by Elsevier Inc.

Strength and endurance training reduces the loss of eccentric hamstring torque observed after soccer specific fatigue.

PubMed

Matthews, Martyn J; Heron, Kate; Todd, Stefanie; Tomlinson, Andrew; Jones, Paul; Delextrat, Anne; Cohen, Daniel D

2017-05-01

To investigate the effect of two hamstring training protocols on eccentric peak torque before and after soccer specific fatigue. Twenty-two university male soccer players. Isokinetic strength tests were performed at 60°/s pre and post fatigue, before and after 2 different training interventions. A 45-min soccer specific fatigue modified BEAST protocol (M-BEAST) was used to induce fatigue. Players were randomly assigned to a 4 week hamstrings conditioning intervention with either a maximum strength (STR) or a muscle endurance (END) emphasis. The following parameters were evaluated: Eccentric peak torque (EccPT), angle of peak torque (APT), and angle specific torques at knee joint angles of 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80° and 90°. There was a significant effect of the M-BEAST on the Eccentric torque angle profile before training as well as significant improvements in post-fatigue torque angle profile following the effects of both strength and muscle endurance interventions. Forty-five minutes of simulated soccer activity leads to reduced eccentric hamstring torque at longer muscle lengths. Short-term conditioning programs (4-weeks) with either a maximum strength or a muscular endurance emphasis can equally reduce fatigue induced loss of strength over this time period. Copyright © 2017 Elsevier Ltd. All rights reserved.

Association of mobile phone radiation with fatigue, headache, dizziness, tension and sleep disturbance in Saudi population.

PubMed

Al-Khlaiwi, Thamir; Meo, Sultan A

2004-06-01

The widespread use of mobile phones has been increased over the past decade; they are now an essential part of business, commerce and society. The use of mobile phones can cause health problems. Therefore, the aim of the present study is to investigate the association of using mobile phones with fatigue, headache, dizziness, tension and sleep disturbance in the Saudi population and provide health and social awareness in using these devices. This study was conducted in the Department of Physiology, College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia during the year 2002 to 2003. In the present study, a total of 437 subjects (55.1% male and 39.9% female) were invited, they have and had been using mobile phones. A questionnaire was distributed regarding detailed history and association of mobile phones with health hazards. The results of the present study showed an association between the use of mobile phones and health hazards. The overall mean percentage for these clinical findings in all groups were headache (21.6%), sleep disturbance (4.%), tension (3.9%), fatigue (3%) and dizziness (2.4%). Based on the results of the present study, we conclude that the use of mobile phones is a risk factor for health hazards and suggest that long term or excessive use of mobile phones should be avoided by health promotion activities such as group discussions, public presentations and through electronic and print media sources.

7075-T6 and 2024-T351 Aluminum Alloy Fatigue Crack Growth Rate Data

NASA Technical Reports Server (NTRS)

Forth, Scott C.; Wright, Christopher W.; Johnston, William M., Jr.

2005-01-01

Experimental test procedures for the development of fatigue crack growth rate data has been standardized by the American Society for Testing and Materials. Over the past 30 years several gradual changes have been made to the standard without rigorous assessment of the affect these changes have on the precision or variability of the data generated. Therefore, the ASTM committee on fatigue crack growth has initiated an international round robin test program to assess the precision and variability of test results generated using the standard E647-00. Crack growth rate data presented in this report, in support of the ASTM roundrobin, shows excellent precision and repeatability.

Modeling and Prediction of Corrosion-Fatigue Failures in AF1410 Steel Test Specimens

DTIC Science & Technology

2009-01-12

PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Structures Division, Code 4.3.3 University of Dayton Research Bldg. 2187 Room 2340A Institute Naval...AND ADDRESS(ES) Office of Naval Research One Liberty Center 875 North Randolph St., Suite 1425 Arlington, VA 22203-1995 11. SPONSOR/MONITOR’S...costs. To address these issues, NAVAIR has initiated a multiyear research program to investigate and quantify the fatigue life reduction due to

Experimental Resource Allocation for Statistical Simulation of Fretting Fatigue Problem (Preprint)

DTIC Science & Technology

2012-08-01

Metals Branch Structural Materials Division Harry R. Millwater , Carolina Dubinsky, and Gulshan Singh University of Texas at San Antonio...GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR(S) Patrick Golden (AFRL/RXCM) Harry R. Millwater , Carolina Dubinsky, and Gulshan...Safety. 1996;54(2-3):133-144 [5] Golden, PJ, Millwater HR and Yang X. Probabilistic Fretting Fatigue Life Prediction of Ti-6Al-4V. International Journal

Nasal Irrigation for Chronic Rhinosinusitis and Fatigue in Patients with Gulf War Syndrome

DTIC Science & Technology

2015-07-01

Syndrome ” PRINCIPAL INVESTIGATOR: David Rabago, MD CONTRACTING ORGANIZATION: University of Wisconsin Systems Board of Regents REPORT DATE...Patients with Gulf War Syndrome ” 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) David Rabago, MD 5d. PROJECT NUMBER 5e. TASK NUMBER...Rhinosinusitis, Fatigue, Gulf War Syndrome , Nasal Irrigation 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a

The effect of progressive muscle relaxation on the management of fatigue and quality of sleep in patients with chronic obstructive pulmonary disease: A randomized controlled clinical trial.

PubMed

Seyedi Chegeni, Pooya; Gholami, Mohammad; Azargoon, Alireza; Hossein Pour, Amir Hossein; Birjandi, Mehdi; Norollahi, Hamed

2018-05-01

To assess the effect of progressive muscle relaxation (PMR) on fatigue and sleep quality of patients with chronic obstructive pulmonary disease (COPD) stages 3 and 4. The pretest posttest clinical trial recruited 91 patients COPD grades 3 and 4. Following random assignment of subjects, the treatment group (n = 45) performed PMR for eight weeks and the control group (n = 46) received routine cares. At baseline and after the intervention, fatigue and sleep quality was assessed. Data obtained were analyzed in SPSS. It was determined that PMR decreased patients' fatigue level and improved some sleep quality subscales including subjective sleep quality, sleep latency, sleep duration and habitual sleep efficiency, but no improvement was found in global sleep quality and other sleep subscales. An eight-week home-based PMR program can be effective in reducing fatigue and improving certain subscales of sleep quality in patients with COPD stages 3,4. (IRCT2016080124080N3). Copyright © 2018 Elsevier Ltd. All rights reserved.

Fatigue crack growth in fiber-metal laminates

NASA Astrophysics Data System (ADS)

Ma, YuE; Xia, ZhongChun; Xiong, XiaoFeng

2014-01-01

Fiber-metal laminates (FMLs) consist of three layers of aluminum alloy 2024-T3 and two layers of glass/epoxy prepreg, and it (it means FMLs) is laminated by Al alloy and fiber alternatively. Fatigue crack growth rates in notched fiber-metal laminates under constant amplitude fatigue loading were studied experimentally and numerically and were compared with them in monolithic 2024-T3 Al alloy plates. It is shown that the fatigue life of FMLs is about 17 times longer than monolithic 2024-T3 Al alloy plate; and crack growth rates in FMLs panels remain constant mostly even when the crack is long, unlike in the monolithic 2024-T3 Al alloy plates. The formula to calculate bridge stress profiles of FMLs was derived based on the fracture theory. A program by Matlab was developed to calculate the distribution of bridge stress in FMLs, and then fatigue growth lives were obtained. Finite element models of FMLs were built and meshed finely to analyze the stress distributions. Both results were compared with the experimental results. They agree well with each other.

A User’s Manual for a Computer Program to Generate Fatigue Spectrum Loading Sequences

DTIC Science & Technology

1978-11-01

cOOOOOOOOOOOOOOOOOOOO0OO0OOOOOOO 3 o jci o0 0 0 o.oQ~ .- ~JJ%CI...N’’? 1". ~’ooooooX!,ooooooooo0ooooooooooo 0OOOOOOOOOOOOOCL 00000000000 Z L VI-) .. tnnont...1 1 1 1 Ed IEND , , 1 ,,, 14 , 1 , 3 , , , , , , NEND 11 ,8 ,3 131 1 , , , , i I I S U L T 1 II , , , 1 1 1f 1:, 1 , 91 6 I ,7 t 8 1, 71 , , , , 1 I...FOR SEGMENTS WITH M3 = 10, 11, OR 12, ONLY WHEN Li = 1. 131 FATIGUE DAMAGE CALCULATION PROGRAM 16PA Page of FORTRAN DATA LOAD SHEET 111-1.3 Prepared by

Fatigue, quality of life and walking ability in adults with cerebral palsy.

PubMed

Lundh, Sofia; Nasic, Salmir; Riad, Jacques

2018-03-01

Few studies on fatigue, quality of life and walking ability in adults with cerebral palsy (CP) are available. It is unclear whether these variables are associated. The aim was to study the influence of CP on fatigue, quality of life, and gait of adult patients. Three-dimensional gait analysis was performed on 24 women and 26 men, mean age 32.1 (range 21.7-67.2), 23 with unilateral and 27 with bilateral CP. The Gait Profile Score was calculated; Fatigue Severity and EQ Visual Analogue scales were used. Fatigue severity was higher than in controls, mean 3.8 (SD 1.8) vs 3.0 (p = 0.012). Fatigue in the unilateral group was 3.3 (SD 1.8) and in the bilateral 4.2 (SD 1.7), (p = 0.07). EQ Visual Analogue scale in the unilateral group was mean 79.5 (21.9) and in the bilateral 64.0 (20.8), p = 0.007. The group with bilateral CP tended toward crouch gait, decreased balance and low walking speed. Muscle work was shifted from the ankle to hip muscles. Fatigue correlated with the Gait Profile Score, CC = 0.31 (p = 0.038), and with knee flexion deviation, CC = 0.31 (p = 0.037). Crouch gait, increased knee flexion in stance, contributes to increased deviation in the lower extremity associated with high fatigue and low quality of life in adults with CP, effects more pronounced in those with bilateral CP. Compensation mechanisms in gait were noted. Rational follow-up programs for CP, ideally identifying risk factors early, should be established to prevent development of fatigue and deterioration of gait in adulthood. Copyright © 2017 Elsevier B.V. All rights reserved.

Learning to Live on a Mars Day: Fatigue Countermeasures during the Phoenix Mars Lander Mission

PubMed Central

Barger, Laura K.; Sullivan, Jason P.; Vincent, Andrea S.; Fiedler, Edna R.; McKenna, Laurence M.; Flynn-Evans, Erin E.; Gilliland, Kirby; Sipes, Walter E.; Smith, Peter H.; Brainard, George C.; Lockley, Steven W.

2012-01-01

Study Objectives: To interact with the robotic Phoenix Mars Lander (PML) spacecraft, mission personnel were required to work on a Mars day (24.65 h) for 78 days. This alien schedule presents a challenge to Earth-bound circadian physiology and a potential risk to workplace performance and safety. We evaluated the acceptability, feasibility, and effectiveness of a fatigue management program to facilitate synchronization with the Mars day and alleviate circadian misalignment, sleep loss, and fatigue. Design: Operational field study. Setting: PML Science Operations Center. Participants: Scientific and technical personnel supporting PML mission. Interventions: Sleep and fatigue education was offered to all support personnel. A subset (n = 19) were offered a short-wavelength (blue) light panel to aid alertness and mitigate/reduce circadian desynchrony. They were assessed using a daily sleep/work diary, continuous wrist actigraphy, and regular performance tests. Subjects also completed 48-h urine collections biweekly for assessment of the circadian 6-sulphatoxymelatonin rhythm. Measurements and Results: Most participants (87%) exhibited a circadian period consistent with adaptation to a Mars day. When synchronized, main sleep duration was 5.98 ± 0.94 h, but fell to 4.91 ± 1.22 h when misaligned (P < 0.001). Self-reported levels of fatigue and sleepiness also significantly increased when work was scheduled at an inappropriate circadian phase (P < 0.001). Prolonged wakefulness (≥ 21 h) was associated with a decline in performance and alertness (P < 0.03 and P < 0.0001, respectively). Conclusions: The ability of the participants to adapt successfully to the Mars day suggests that future missions should utilize a similar circadian rhythm and fatigue management program to reduce the risk of sleepiness-related errors that jeopardize personnel safety and health during critical missions. Citation: Barger LK; Sullivan JP; Vincent AS; Fiedler ER; McKenna LM; Flynn-Evans EE; Gilliland K; Sipes WE; Smith PH; Brainard GC; Lockley SW. Learning to live on a Mars day: fatigue countermeasures during the Phoenix Mars Lander mission. SLEEP 2012;35(10):1423-1435. PMID:23024441

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roach, Dennis Patrick; Rackow, Kirk A.

A typical aircraft can experience over 2,000 fatigue cycles (cabin pressurizations) and even greater flight hours in a single year. An unavoidable by-product of aircraft use is that crack, impact, and corrosion flaws develop throughout the aircraft's skin and substructure elements. Economic barriers to the purchase of new aircraft have placed even greater demands on efficient and safe repair methods. The use of bonded composite doublers offers the airframe manufacturers and aircraft maintenance facilities a cost effective method to safely extend the lives of their aircraft. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, itmore » is now possible to bond a single Boron-Epoxy composite doubler to the damaged structure. The FAA's Airworthiness Assurance Center at Sandia National Labs (AANC), Boeing, and Federal Express completed a pilot program to validate and introduce composite doubler repair technology to the U.S. commercial aircraft industry. This project focused on repair of DC-10 fuselage structure and its primary goal was to demonstrate routine use of this repair technology using niche applications that streamline the design-to-installation process. As composite doubler repairs gradually appear in the commercial aircraft arena, successful flight operation data is being accumulated. These commercial aircraft repairs are not only demonstrating the engineering and economic advantages of composite doubler technology but they are also establishing the ability of commercial maintenance depots to safely adopt this repair technique. This report presents the array of engineering activities that were completed in order to make this technology available for widespread commercial aircraft use. Focused laboratory testing was conducted to compliment the field data and to address specific issues regarding damage tolerance and flaw growth in composite doubler repairs. Fatigue and strength tests were performed on a simulated wing repair using a substandard design and a flawed installation. In addition, the new Sol-Gel surface preparation technique was evaluated. Fatigue coupon tests produced Sol-Gel results that could be compared with a large performance database from conventional, riveted repairs. It was demonstrated that not only can composite doublers perform well in severe off-design conditions (low doubler stiffness and presence of defects in doubler installation) but that the Sol-Gel surface preparation technique is easier and quicker to carry out while still producing optimum bonding properties. Nondestructive inspection (NDI) methods were developed so that the potential for disbond and delamination growth could be monitored and crack growth mitigation could be quantified. The NDI methods were validated using full-scale test articles and the FedEx aircraft installations. It was demonstrated that specialized NDI techniques can detect flaws in composite doubler installations before they reach critical size. Probability of Detection studies were integrated into the FedEx training in order to quantify the ability of aircraft maintenance depots to properly monitor these repairs. In addition, Boeing Structural Repair and Nondestructive Testing Manuals were modified to include composite doubler repair and inspection procedures. This report presents the results from the FedEx Pilot Program that involved installation and surveillance of numerous repairs on operating aircraft. Results from critical NDI evaluations are reported in light of damage tolerance assessments for bonded composite doublers. This work has produced significant interest from airlines and aircraft manufacturers. The successful Pilot Program produced flight performance history to establish the durability of bonded composite patches as a permanent repair on commercial aircraft structures. This report discusses both the laboratory data and Pilot Program results from repair installations on operating aircraft to introduce composite doubler repairs into mainstream commercial aircraft use.« less

Implementation and Validation of the Viscoelastic Continuum Damage Theory for Asphalt Mixture and Pavement Analysis in Brazil

NASA Astrophysics Data System (ADS)

Nascimento, Luis Alberto Herrmann do

This dissertation presents the implementation and validation of the viscoelastic continuum damage (VECD) model for asphalt mixture and pavement analysis in Brazil. It proposes a simulated damage-to-fatigue cracked area transfer function for the layered viscoelastic continuum damage (LVECD) program framework and defines the model framework's fatigue cracking prediction error for asphalt pavement reliability-based design solutions in Brazil. The research is divided into three main steps: (i) implementation of the simplified viscoelastic continuum damage (S-VECD) model in Brazil (Petrobras) for asphalt mixture characterization, (ii) validation of the LVECD model approach for pavement analysis based on field performance observations, and defining a local simulated damage-to-cracked area transfer function for the Fundao Project's pavement test sections in Rio de Janeiro, RJ, and (iii) validation of the Fundao project local transfer function to be used throughout Brazil for asphalt pavement fatigue cracking predictions, based on field performance observations of the National MEPDG Project's pavement test sections, thereby validating the proposed framework's prediction capability. For the first step, the S-VECD test protocol, which uses controlled-on-specimen strain mode-of-loading, was successfully implemented at the Petrobras and used to characterize Brazilian asphalt mixtures that are composed of a wide range of asphalt binders. This research verified that the S-VECD model coupled with the GR failure criterion is accurate for fatigue life predictions of Brazilian asphalt mixtures, even when very different asphalt binders are used. Also, the applicability of the load amplitude sweep (LAS) test for the fatigue characterization of the asphalt binders was checked, and the effects of different asphalt binders on the fatigue damage properties of the asphalt mixtures was investigated. The LAS test results, modeled according to VECD theory, presented a strong correlation with the asphalt mixtures' fatigue performance. In the second step, the S-VECD test protocol was used to characterize the asphalt mixtures used in the 27 selected Fundao project test sections and subjected to real traffic loading. Thus, the asphalt mixture properties, pavement structure data, traffic loading, and climate were input into the LVECD program for pavement fatigue cracking performance simulations. The simulation results showed good agreement with the field-observed distresses. Then, a damage shift approach, based on the initial simulated damage growth rate, was introduced in order to obtain a unique relationship between the LVECD-simulated shifted damage and the pavement-observed fatigue cracked areas. This correlation was fitted to a power form function and defined as the averaged reduced damage-to-cracked area transfer function. The last step consisted of using the averaged reduced damage-to-cracked area transfer function that was developed in the Fundao project to predict pavement fatigue cracking in 17 National MEPDG project test sections. The procedures for the material characterization and pavement data gathering adopted in this step are similar to those used for the Fundao project simulations. This research verified that the transfer function defined for the Fundao project sections can be used for the fatigue performance predictions of a wide range of pavements all over Brazil, as the predicted and observed cracked areas for the National MEPDG pavements presented good agreement, following the same trends found for the Fundao project pavement sites. Based on the prediction errors determined for all 44 pavement test sections (Fundao and National MEPDG test sections), the proposed framework's prediction capability was determined so that reliability-based solutions can be applied for flexible pavement design. It was concluded that the proposed LVECD program framework has very good fatigue cracking prediction capability.

Federal policies to promote the widespread utilization of photovoltaic systems. Supplement: Review and critique

NASA Technical Reports Server (NTRS)

Smith, J. L.

1980-01-01

Review comments of the Congressional report entitled 'Federal Policies to Promote the Widespread Utilization of Photovoltaic Systems' are presented. Responses to the review comments by the Jet Propulsion Laboratory, preparer of the Congressional report, are also presented. The Congressional report discussed various issues related to promoting the deployment of photovoltaic systems through the Federal Photovoltaic Program. Various program strategies and funding levels were examined.

Changes in lower extremity biomechanics due to a short-term fatigue protocol.

PubMed

Cortes, Nelson; Greska, Eric; Kollock, Roger; Ambegaonkar, Jatin; Onate, James A

2013-01-01

Noncontact anterior cruciate ligament injury has been reported to occur during the later stages of a game when fatigue is most likely present. Few researchers have focused on progressive changes in lower extremity biomechanics that occur throughout fatiguing. To evaluate the effects of a sequential fatigue protocol on lower extremity biomechanics during a sidestep-cutting task (SS). Controlled laboratory study. Laboratory. Eighteen uninjured female collegiate soccer players (age = 19.2 ± 0.9 years, height = 1.66 ± 0.5 m, mass = 61.6 ± 5.1 kg) volunteered. The independent variable was fatigue level, with 3 levels (prefatigue, 50% fatigue, and 100% fatigue). Using 3-dimensional motion capture, we assessed lower extremity biomechanics during the SS. Participants alternated between a fatigue protocol that solicited different muscle groups and mimicked actual sport situations and unanticipated SS trials. The process was repeated until fatigue was attained. Dependent variables were hip- and knee-flexion and abduction angles and internal moments measured at initial contact and peak stance and defined as measures obtained between 0% and 50% of stance phase. Knee-flexion angle decreased from prefatigue (-17° ± 5°) to 50% fatigue (-16° ± 6°) and to 100% fatigue (-14° ± 4°) (F2,34 = 5.112, P = .004). Knee flexion at peak stance increased from prefatigue (-52.9° ± 5.6°) to 50% fatigue (-56.1° ± 7.2°) but decreased from 50% to 100% fatigue (-50.5° ± 7.1°) (F2,34 = 8.282, P = 001). Knee-adduction moment at peak stance increased from prefatigue (0.49 ± 0.23 Nm/kgm) to 50% fatigue (0.55 ± 0.25 Nm/kgm) but decreased from 50% to 100% fatigue (0.37 ± 0.24) (F2,34 = 3.755, P = 03). Hip-flexion angle increased from prefatigue (45.4° ± 10.9°) to 50% fatigue (46.2° ± 11.2°) but decreased from 50% to 100% fatigue (40.9° ± 11.3°) (F2,34 = 6.542, P = .004). Hip flexion at peak stance increased from prefatigue (49.8° ± 9.9°) to 50% fatigue (52.9° ± 12.1°) but decreased from 50% to 100% fatigue (46.3° ± 12.9°) (F2,34 = 8.639, P = 001). Hip-abduction angle at initial contact decreased from prefatigue (-13.8° ± 6.6°) to 50% fatigue (-9.1° ± 6.5°) and to 100% fatigue (-7.8° ± 6.5°) (F2,34 = 11.228, P < .001). Hip-adduction moment decreased from prefatigue (0.14 ± 0.13 Nm/kgm) to 50% fatigue (0.08 ± 0.13 Nm/kgm) and to 100% fatigue (0.06 ± 0.05 Nm/kg) (F2,34 = 5.767, P = .007). The detrimental effects of fatigue on sagittal and frontal mechanics of the hip and knee were visible at 50% of the participants' maximal fatigue and became more marked at 100% fatigue. Anterior cruciate ligament injury-prevention programs should emphasize feedback on proper mechanics throughout an entire practice and not only at the beginning of practice.

Changes in Lower Extremity Biomechanics Due to a Short-Term Fatigue Protocol

PubMed Central

Cortes, Nelson; Greska, Eric; Kollock, Roger; Ambegaonkar, Jatin; Onate, James A.

2013-01-01

Context: Noncontact anterior cruciate ligament injury has been reported to occur during the later stages of a game when fatigue is most likely present. Few researchers have focused on progressive changes in lower extremity biomechanics that occur throughout fatiguing. Objective: To evaluate the effects of a sequential fatigue protocol on lower extremity biomechanics during a sidestep-cutting task (SS). Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Eighteen uninjured female collegiate soccer players (age = 19.2 ± 0.9 years, height = 1.66 ± 0.5 m, mass = 61.6 ± 5.1 kg) volunteered. Intervention(s): The independent variable was fatigue level, with 3 levels (prefatigue, 50% fatigue, and 100% fatigue). Using 3-dimensional motion capture, we assessed lower extremity biomechanics during the SS. Participants alternated between a fatigue protocol that solicited different muscle groups and mimicked actual sport situations and unanticipated SS trials. The process was repeated until fatigue was attained. Main Outcome Measure(s): Dependent variables were hip- and knee-flexion and abduction angles and internal moments measured at initial contact and peak stance and defined as measures obtained between 0% and 50% of stance phase. Results: Knee-flexion angle decreased from prefatigue (−17° ± 5°) to 50% fatigue (−16° ± 6°) and to 100% fatigue (−14° ± 4°) (F2,34 = 5.112, P = .004). Knee flexion at peak stance increased from prefatigue (−52.9° ± 5.6°) to 50% fatigue (−56.1° ± 7.2°) but decreased from 50% to 100% fatigue (−50.5° ± 7.1°) (F2,34 = 8.282, P = 001). Knee-adduction moment at peak stance increased from prefatigue (0.49 ± 0.23 Nm/kgm) to 50% fatigue (0.55 ± 0.25 Nm/kgm) but decreased from 50% to 100% fatigue (0.37 ± 0.24) (F2,34 = 3.755, P = 03). Hip-flexion angle increased from prefatigue (45.4° ± 10.9°) to 50% fatigue (46.2° ± 11.2°) but decreased from 50% to 100% fatigue (40.9° ± 11.3°) (F2,34 = 6.542, P = .004). Hip flexion at peak stance increased from prefatigue (49.8° ± 9.9°) to 50% fatigue (52.9° ± 12.1°) but decreased from 50% to 100% fatigue (46.3° ± 12.9°) (F2,34 = 8.639, P = 001). Hip-abduction angle at initial contact decreased from prefatigue (−13.8° ± 6.6°) to 50% fatigue (−9.1° ± 6.5°) and to 100% fatigue (−7.8° ± 6.5°) (F2,34 = 11.228, P < .001). Hip-adduction moment decreased from prefatigue (0.14 ± 0.13 Nm/kgm) to 50% fatigue (0.08 ± 0.13 Nm/kgm) and to 100% fatigue (0.06 ± 0.05 Nm/kg) (F2,34 = 5.767, P = .007). Conclusions: The detrimental effects of fatigue on sagittal and frontal mechanics of the hip and knee were visible at 50% of the participants' maximal fatigue and became more marked at 100% fatigue. Anterior cruciate ligament injury-prevention programs should emphasize feedback on proper mechanics throughout an entire practice and not only at the beginning of practice. PMID:23675789

Fatigue in hospital nurses - 'Supernurse' culture is a barrier to addressing problems: A qualitative interview study.

PubMed

Steege, Linsey M; Rainbow, Jessica G

2017-02-01

Fatigue in hospital nurses is associated with decreased nurse satisfaction, increased turnover and negative patient outcomes. Addressing fatigue in nurses has been identified as a priority by many organizations worldwide in an effort to promote both a culture of patient safety and a healthy nursing workforce. The overall aim of this study was to explore barriers and facilitators within the hospital nurse work system to nurse coping and fatigue. The purpose of this paper is to describe emergent themes that offer new insight describing the relationships among nurse perceptions of fatigue, nursing professional culture, and implications for the nursing workforce. A qualitative exploratory study was used to explore nurse identified sources, barriers to addressing, and consequences of fatigue. Twenty-two nurses working in intensive care and medical-surgical units within a large academic medical center in the United States participated in the interviews. Interviews with the participants followed a semi-structured interview guide that included questions eliciting participants' views on nurse fatigue levels, consequences of fatigue, and barriers to addressing fatigue. The interview transcripts were analyzed using directed content analysis guided by the Systems Engineering Initiative for Patient Safety (SEIPS) model. Additional themes that did not directly align with the SEIPS model were also identified. All nurses in the current study experienced fatigue; yet they had varying perspectives on the importance of addressing fatigue in relation to other health systems challenges. A new construct related to nursing professional culture was identified and defined as "Supernurse". Identified subthemes of Supernurse include: extraordinary powers used for good; cloak of invulnerability; no sidekick; Kryptonite, and an alterego. These values, beliefs, and behaviors define the specific aspects of nursing professional culture that can act as barriers to fatigue risk management programs and achieving safety culture in hospital organizations. Nurse fatigue and attributes of nurse professional culture also have implications for nurse satisfaction and retention. Findings from this study further support the role of nursing professional culture as an important barrier to effectively addressing fatigue in nursing work systems. Future work is needed to identify and evaluate innovative culture change models and strategies to target these barriers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Resistance exercise improves physical fatigue in women with fibromyalgia: a randomized controlled trial.

PubMed

Ericsson, Anna; Palstam, Annie; Larsson, Anette; Löfgren, Monika; Bileviciute-Ljungar, Indre; Bjersing, Jan; Gerdle, Björn; Kosek, Eva; Mannerkorpi, Kaisa

2016-07-30

Fibromyalgia (FM) affects approximately 1-3 % of the general population. Fatigue limits the work ability and social life of patients with FM. A few studies of physical exercise have included measures of fatigue in FM, indicating that exercise can decrease fatigue levels. There is limited knowledge about the effects of resistance exercise on multiple dimensions of fatigue in FM. The present study is a sub-study of a multicenter randomized controlled trial in women with FM. The purpose of the present sub-study was to examine the effects of a person-centered progressive resistance exercise program on multiple dimensions of fatigue in women with FM, and to investigate predictors of the potential change in fatigue. A total of 130 women with FM (age 22-64 years) were included in this assessor-blinded randomized controlled multicenter trial examining the effects of person-centered progressive resistance exercise compared with an active control group. The intervention was performed twice a week for 15 weeks. Outcomes were five dimensions of fatigue measured with the Multidimensional Fatigue Inventory (MFI-20). Information about background was collected and the women also completed several health-related questionnaires. Multiple linear stepwise regression was used to analyze predictors of change in fatigue in the total population. A higher improvement was found at the post-treatment examination for change in the resistance exercise group, as compared to change in the active control group in the MFI-20 subscale of physical fatigue (resistance group Δ -1.7, SD 4.3, controls Δ 0.0, SD 2.7, p = 0.013), with an effect size of 0.33. Sleep efficiency was the strongest predictor of change in the MFI-20 subscale general fatigue (beta = -0.54, p = 0.031, R (2) = 0.05). Participating in resistance exercise (beta = 1.90, p = 0.010) and working fewer hours per week (beta = 0.84, p = 0.005) were independent significant predictors of change in physical fatigue (R (2) = 0.14). Person-centered progressive resistance exercise improved physical fatigue in women with FM when compared to an active control group. ClinicalTrials.gov NCT01226784 . Registered 21 October 2010.

Hydrotherapy for the treatment of pain in people with multiple sclerosis: a randomized controlled trial.

PubMed

Castro-Sánchez, Adelaida María; Matarán-Peñarrocha, Guillermo A; Lara-Palomo, Inmaculada; Saavedra-Hernández, Manuel; Arroyo-Morales, Manuel; Moreno-Lorenzo, Carmen

2012-01-01

Background. Multiple sclerosis (MS) is a chronic demyelinating neurological disease. Several studies have reported that complementary and alternative therapies can have positive effects against pain in these patients. Objective. The objective was to investigate the effectiveness of an Ai-Chi aquatic exercise program against pain and other symptoms in MS patients. Methods. In this randomized controlled trial, 73 MS patients were randomly assigned to an experimental or control group for a 20-week treatment program. The experimental group underwent 40 sessions of Ai-Chi exercise in swimming pool and the control group 40 sessions of abdominal breathing and contraction-relaxation exercises in therapy room. Outcome variables were pain, disability, spasm, depression, fatigue, and autonomy, which were assessed before the intervention and immediately and at 4 and 10 weeks after the last treatment session. Results. The experimental group showed a significant (P < 0.028) and clinically relevant decrease in pain intensity versus baseline, with an immediate posttreatment reduction in median visual analogue scale scores of 50% that was maintained for up to 10 weeks. Significant improvements were also observed in spasm, fatigue, disability, and autonomy. Conclusion. According to these findings, an Ai-Chi aquatic exercise program improves pain, spasms, disability, fatigue, depression, and autonomy in MS patients.

Hydrotherapy for the Treatment of Pain in People with Multiple Sclerosis: A Randomized Controlled Trial

PubMed Central

Castro-Sánchez, Adelaida María; Matarán-Peñarrocha, Guillermo A.; Lara-Palomo, Inmaculada; Saavedra-Hernández, Manuel; Arroyo-Morales, Manuel; Moreno-Lorenzo, Carmen

2012-01-01

Background. Multiple sclerosis (MS) is a chronic demyelinating neurological disease. Several studies have reported that complementary and alternative therapies can have positive effects against pain in these patients. Objective. The objective was to investigate the effectiveness of an Ai-Chi aquatic exercise program against pain and other symptoms in MS patients. Methods. In this randomized controlled trial, 73 MS patients were randomly assigned to an experimental or control group for a 20-week treatment program. The experimental group underwent 40 sessions of Ai-Chi exercise in swimming pool and the control group 40 sessions of abdominal breathing and contraction-relaxation exercises in therapy room. Outcome variables were pain, disability, spasm, depression, fatigue, and autonomy, which were assessed before the intervention and immediately and at 4 and 10 weeks after the last treatment session. Results. The experimental group showed a significant (P < 0.028) and clinically relevant decrease in pain intensity versus baseline, with an immediate posttreatment reduction in median visual analogue scale scores of 50% that was maintained for up to 10 weeks. Significant improvements were also observed in spasm, fatigue, disability, and autonomy. Conclusion. According to these findings, an Ai-Chi aquatic exercise program improves pain, spasms, disability, fatigue, depression, and autonomy in MS patients. PMID:21785645

Feasibility of an inpatient exercise intervention for children undergoing hematopoietic stem cell transplant.

PubMed

Bogg, Tina Fung Ting; Broderick, Carolyn; Shaw, Peter; Cohn, Richard; Naumann, Fiona Leigh

2015-12-01

With improving survival rates following HSCT in children, QOL and management of short- and long-term effects need to be considered. Exercise may help mitigate fatigue and declines in fitness and strength. The aims of this study were to assess the feasibility of an inpatient exercise intervention for children undergoing HSCT and observe the changes in physical and psychological health. Fourteen patients were recruited, mean age 10 yr. A 6MWT, isometric upper and lower body strength, balance, fatigue, and QOL were assessed prior to Tx and six wk post-Tx. A supervised exercise program was offered five days per week during the inpatient period and feasibility assessed through uptake rate. The study had 100% program completion and 60% uptake rate of exercise sessions. The mean (± s.d.) weekly activity was 117.5 (± 79.3) minutes. Younger children performed significantly more minutes of exercise than adolescents. At reassessment, strength and fatigue were stabilized while aerobic fitness and balance decreased. QOL revealed a non-statistical trend towards improvement. No exercise-related adverse events were reported. A supervised inpatient exercise program is safe and feasible, with potential physiological and psychosocial benefits. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Computational simulation of probabilistic lifetime strength for aerospace materials subjected to high temperature, mechanical fatigue, creep and thermal fatigue

NASA Technical Reports Server (NTRS)

Boyce, Lola; Bast, Callie C.; Trimble, Greg A.

1992-01-01

This report presents the results of a fourth year effort of a research program, conducted for NASA-LeRC by the University of Texas at San Antonio (UTSA). The research included on-going development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic material strength degradation model, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subject to a number of effects or primitive variables. These primitive variables may include high temperature, fatigue or creep. In most cases, strength is reduced as a result of the action of a variable. This multifactor interaction strength degradation equation has been randomized and is included in the computer program, PROMISS. Also included in the research is the development of methodology to calibrate the above-described constitutive equation using actual experimental materials data together with regression analysis of that data, thereby predicting values for the empirical material constants for each effect or primitive variable. This regression methodology is included in the computer program, PROMISC. Actual experimental materials data were obtained from industry and the open literature for materials typically for applications in aerospace propulsion system components. Material data for Inconel 718 has been analyzed using the developed methodology.

Computational simulation of probabilistic lifetime strength for aerospace materials subjected to high temperature, mechanical fatigue, creep, and thermal fatigue

NASA Technical Reports Server (NTRS)

Boyce, Lola; Bast, Callie C.; Trimble, Greg A.

1992-01-01

The results of a fourth year effort of a research program conducted for NASA-LeRC by The University of Texas at San Antonio (UTSA) are presented. The research included on-going development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic material strength degradation model, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subjected to a number of effects or primitive variables. These primitive variables may include high temperature, fatigue, or creep. In most cases, strength is reduced as a result of the action of a variable. This multifactor interaction strength degradation equation was randomized and is included in the computer program, PROMISC. Also included in the research is the development of methodology to calibrate the above-described constitutive equation using actual experimental materials data together with regression analysis of that data, thereby predicting values for the empirical material constants for each effect or primitive variable. This regression methodology is included in the computer program, PROMISC. Actual experimental materials data were obtained from industry and the open literature for materials typically for applications in aerospace propulsion system components. Material data for Inconel 718 was analyzed using the developed methodology.

The Mediating Role of Exercise on Relationships Between Fatigue, Sleep Quality, and Quality of Life for Adolescents With Cancer.

PubMed

Wu, Wei-Wen; Jou, Shiann-Tarng; Liang, Shu-Yuan; Tsai, Shao-Yu

2018-02-27

Fatigue and poor sleep are two of the most common and most distressing symptoms for adolescents with cancer. These 2 symptoms concurrently heighten distress, further decreasing quality of life (QoL). The aims of this study were to describe the degree of exercise involvement, fatigue, sleep quality, and QoL among adolescents with cancer and to determine whether exercise mediates the relationships between (a) fatigue and QoL and (b) sleep quality and QoL. A cross-sectional study of 100 participants was conducted. Multiple regression was performed to examine the mediation relationship. Participants in the off-treatment group had a significantly higher degree of exercise involvement, as well as less fatigue, greater sleep quality, and less QoL distress. Exercise partially mediated the adverse effect of fatigue on QoL for adolescents undergoing cancer treatment, accounting for 49.80% of the total variation; exercise partially mediated the adverse effect of poor sleep on QoL for adolescents both in treatment and in survivorship, accounting for 42.06% and 28.71% of the total variations, respectively. Exercise partially mediated the relationship between fatigue and QoL for adolescents in cancer treatment and partially mediated the relationship between sleep quality and QoL both for those in cancer treatment and for those in survivorship. Developing tailored exercise programs based on both treatment status and the degree of fatigue and sleep quality is important. In-service education that enhances nurses' awareness of the importance of exercise in improving adolescents' QoL is recommended.

Low cycle fatigue behaviour of a plasma-sprayed coating material

NASA Technical Reports Server (NTRS)

Gayda, J.; Gabb, T. P.; Miner, R. V.

1986-01-01

Single crystal nickel-base superalloys employed in turbine blade applications are often used with a plasma spray coating for oxidation and hot corrosion resistance. These coatings may also affect fatigue life of the superalloy substrate. As part of a large program to understand the fatigue behavior of coated single crystals, fully reversed, total strain controlled fatigue tests were run on a free standing NiCoCrAlY coating alloy, PWA 276, at 0.1 Hz. Fatigue tests were conducted at 650 C, where the NiCoCrAlY alloy has modest ductility, and at 1050 C, where it is extremely ductile, showing tensile elongation in excess of 100 percent. At the lower test temperature, deformation induced disordering softened the NiCoCrAlY alloy, while at the higher test temperature cyclic hardening was observed which was linked to gradual coarsening of the two phase microstructure. Fatigue life of the NiCoCrAlY alloy was significantly longer at the higher temperature. Further, the life of the NiCoCrAlY alloy exceeds that of coated, /001/-oriented PWA 1480 single crystals at 1050 C but at 650 C the life of the coated crystal is greater than that of the NiCoCrAlY alloy on a total strain basis.

Pilot fatigue survey: exploring fatigue factors in air medical operations.

PubMed

Gregory, Kevin B; Winn, William; Johnson, Kent; Rosekind, Mark R

2010-01-01

Humans confront significant physiological challenges with sleep and alertness when working in 24/7 operations. A web-based national survey of air medical pilots examined issues relevant to fatigue and sleep management. Six hundred ninety-seven responses were received, with a majority of rotor wing pilots working 3/3/7 and 7/7 duty schedules. Over 84% of the pilots reported that fatigue had affected their flight performance; less than 28% reported "nodding off" during flight. More than 90% reported a separate work site "rest" room with a bed available. Over 90% reported no company policies restricting on-duty sleep. Approximately half of the pilots reported getting 4 hours or more sleep during a typical night shift. Approximately half reported that sleep inertia had never compromised flight safety. Over 90% reported that it was better to sleep during the night and overcome sleep inertia if necessary. Survey results reflected practices that can mitigate the degrading effects of fatigue, including the availability of designated work-site sleep rooms. As demands continue to evolve, the need remains for sustained efforts to address fatigue-related risks in the air medical transport industry. This includes further study of sleep inertia issues and the need for alertness management programs. Copyright © 2010 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.

Creep fatigue life prediction for engine hot section materials (isotropic)

NASA Technical Reports Server (NTRS)

Moreno, Vito; Nissley, David; Lin, Li-Sen Jim

1985-01-01

The first two years of a two-phase program aimed at improving the high temperature crack initiation life prediction technology for gas turbine hot section components are discussed. In Phase 1 (baseline) effort, low cycle fatigue (LCF) models, using a data base generated for a cast nickel base gas turbine hot section alloy (B1900+Hf), were evaluated for their ability to predict the crack initiation life for relevant creep-fatigue loading conditions and to define data required for determination of model constants. The variables included strain range and rate, mean strain, strain hold times and temperature. None of the models predicted all of the life trends within reasonable data requirements. A Cycle Damage Accumulation (CDA) was therefore developed which follows an exhaustion of material ductility approach. Material ductility is estimated based on observed similarities of deformation structure between fatigue, tensile and creep tests. The cycle damage function is based on total strain range, maximum stress and stress amplitude and includes both time independent and time dependent components. The CDA model accurately predicts all of the trends in creep-fatigue life with loading conditions. In addition, all of the CDA model constants are determinable from rapid cycle, fully reversed fatigue tests and monotonic tensile and/or creep data.

New optomechanical approach to quantitative characterization of fatigue behavior of dynamically loaded structures

NASA Astrophysics Data System (ADS)

Furlong, Cosme; Pryputniewicz, Ryszard J.

1995-06-01

The basic relationships between stress and strain under cyclic conditions of loading are not at present well understood. It would seem that information of this type is vital for a fundamental approach to understand the fatigue behavior of dynamically loaded structures. In this paper, experimental and computational methods are utilized to study the fatigue behavior of a thin aluminum cantilever plate subjected to dynamic loading. The studies are performed by combining optomechanical and finite element methods. The cantilever plate is loaded periodically by excitation set at a fixed amplitude and at a specific resonance frequency of the plate. By continuously applying this type of loading and using holographic interferometry, the behavior of the plate during a specific period of time is investigated. Quantitative information is obtained from laser vibrometry data which are utilized by a finite element program to calculate strains and stresses assuming a homogeneous and isotropic material and constant strain elements. It is shown that the use of experimental and computational hybrid methodologies allows identification of different zones of the plate that are fatigue critical. This optomechanical approach proves to be a viable tool for understanding of fatigue behavior of mechanical components and for performing optimization of structures subjected to fatigue conditions.

Feasibility of a Cognitive Behavioral Intervention to Manage Fatigue in Individuals With Traumatic Brain Injury: A Pilot Study.

PubMed

Raina, Ketki D; Morse, Jennifer Q; Chisholm, Denise; Leibold, Mary Lou; Shen, Jennifer; Whyte, Ellen

2016-01-01

To evaluate the feasibility of conducting a randomized clinical trial of an Internet-based manualized intervention to teach individuals with traumatic brain injury to manage their fatigue. Community dwelling. Forty-one participants randomized to Maximizing Energy (MAX) intervention group (n = 20) and Health Education group (n = 21). The experimental group (MAX intervention) received an 8-week program that combined education and Problem-Solving Therapy to teach individuals to manage fatigue-related problems. The attention control group received health education. Primary outcome measures pertained to the feasibility of conducting the trial. Secondary outcomes were fatigue impact and fatigue severity assessed at baseline and postintervention. Of the 65 participants referred, 41 were enrolled (63% recruitment rate), of which 3 withdrew (92% retention rate). Participants in the experimental and control groups completed their homework 75% and 85% of the time, respectively, and were equally engaged in the sessions. Participants in the experimental group were able to learn and implement the MAX intervention steps. Effect sizes for all measures ranged from small (-0.17) to medium (-0.58) in favor of the intervention group. Findings from the study suggest that the MAX intervention is feasible to administer to individuals with post-traumatic brain injury fatigue.

The low cycle fatigue behavior of a plasma-sprayed coating material

NASA Technical Reports Server (NTRS)

Gayda, J.; Gabb, T. P.; Miner, R. V., Jr.

1986-01-01

Single crystal nickel-base superalloys employed in turbine blade applications are often used with a plasma spray coating for oxidation and hot corrosion resistance. These coatings may also affect fatigue life of the superalloy substrate. As part of a large program to understand the fatigue behavior of coated single crystals, fully reversed, total strain controlled fatigue tests were run on a free standing NiCoCrAlY coating alloy, PWA 276, at 0.1 Hz. Fatigue tests were conducted at 650 C, where the NiCoCrAlY alloy has modest ductility, and at 1050 C, where it is extremely ductile, showing tensile elongation in excess of 100 percent. At the lower test temperature, deformation induced disordering softened the NiCoCrAlY alloy, while at the higher test temperature cyclic hardening was observed which was linked to gradual coarsening of the two phase microstructure. Fatigue life of the NiCoCrAlY alloy was significantly longer at the higher temperature. Further, the life of the NiCoCrAlY alloy exceeds that of coated, /001/-oriented PWA 1480 single crystals at 1050 C, but at 650 C the life of the coated crystal is greater than that of the NiCoCrAlY alloy on a total strain basis.

A combined inspiratory and expiratory muscle training program improves respiratory muscle strength and fatigue in multiple sclerosis.

PubMed

Ray, Andrew D; Udhoji, Supriya; Mashtare, Terry L; Fisher, Nadine M

2013-10-01

To determine the effects of a short-duration, combined (inspiratory and expiratory), progressive resistance respiratory muscle training (RMT) protocol on respiratory muscle strength, fatigue, health-related quality of life, and functional performance in individuals with mild-to-moderate multiple sclerosis (MS). Quasi-experimental before-after trial. University rehabilitation research laboratory. Volunteers with MS (N=21) were divided into 2 groups: RMT (n=11; 9 women, 2 men; mean age ± SD, 50.9 ± 5.7y, mean Expanded Disability Status Scale score ± SD, 3.2 ± 1.9) and a control group that did not train (n=10; 7 women, 3 men; mean age ± SD, 56.2 ± 8.8y, mean Expanded Disability Status Scale score ± SD, 4.4 ± 2.1). Expanded Disability Status Scale scores ranged from 1 to ≤6.5. No patients withdrew from the study. Training was a 5-week combined progressive resistance RMT program, 3d/wk, 30 minutes per session. The primary outcome measures were maximal inspiratory pressure and expiratory pressure and the Modified Fatigue Impact Scale. All subjects completed secondary measures of pulmonary function, the six-minute walk test, the timed stair climb, the Multiple Sclerosis Self-Efficacy Scale, the Medical Outcomes Study 36-Item Short-Form Health Survey, and the Physical Activity Disability Scale. Maximal inspiratory pressure and expiratory pressure (mean ± SD) increased 35% ± 22% (P<.001) and 26% ± 17% (P<.001), respectively, whereas no changes were noted in the control group (12% ± 23% and -4% ± 17%, respectively). RMT improved fatigue (Modified Fatigue Impact Scale, P<.029), with no change or worsening in the control group. No changes were noted in the six-minute walk test, stair climb, Multiple Sclerosis Self-Efficacy Scale, or Physical Activity Disability Scale in the RMT group. The control group had decreases in emotional well-being and general health (Medical Outcomes Study 36-Item Short-Form Health Survey). A short-duration, combined RMT program improved inspiratory and expiratory muscle strength and reduced fatigue in patients with mild to moderate MS. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effects of soluble milk protein or casein supplementation on muscle fatigue following resistance training program: a randomized, double-blind, and placebo-controlled study

PubMed Central

2014-01-01

Background The effects of protein supplementation on muscle thickness, strength and fatigue seem largely dependent on its composition. The current study compared the effects of soluble milk protein, micellar casein, and a placebo on strength and fatigue during and after a resistance training program. Methods Sixty-eight physically active men participated in this randomized controlled trial and underwent 10 weeks of lower-body resistance training. Participants were randomly assigned to the Placebo (PLA), Soluble Milk Protein (SMP, with fast digestion rate) or Micellar Casein (MC, with slow digestion rate) group. During the 10-week training period, participants were instructed to take 30 g of the placebo or protein twice a day, or three times on training days. Tests were performed on quadriceps muscles at inclusion (PRE), after 4 weeks (MID) and after 10 weeks (POST) of training. They included muscle endurance (maximum number of repetitions during leg extensions using 70% of the individual maximal load), fatigue (decrease in muscle power after the endurance test), strength, power and muscle thickness. Results Muscle fatigue was significantly lower (P < 0.05) in the SMP group at MID and POST (-326.8 ± 114.1 W and -296.6 ± 130.1 W, respectively) as compared with PLA (-439.2 ± 153.9 W and -479.2 ± 138.1 W, respectively) and MC (-415.1 ± 165.1 W and -413.7 ± 139.4 W, respectively). Increases in maximal muscle power, strength, endurance and thickness were not statistically different between groups. Conclusions The present study demonstrated that protein composition has a large influence on muscular performance after prolonged resistance training. More specifically, as compared with placebo or micellar casein, soluble milk protein (fast digestible) appeared to significantly reduce muscle fatigue induced by intense resistance exercise. PMID:25057266

Effects of soluble milk protein or casein supplementation on muscle fatigue following resistance training program: a randomized, double-blind, and placebo-controlled study.

PubMed

Babault, Nicolas; Deley, Gaëlle; Le Ruyet, Pascale; Morgan, François; Allaert, François André

2014-01-01

The effects of protein supplementation on muscle thickness, strength and fatigue seem largely dependent on its composition. The current study compared the effects of soluble milk protein, micellar casein, and a placebo on strength and fatigue during and after a resistance training program. Sixty-eight physically active men participated in this randomized controlled trial and underwent 10 weeks of lower-body resistance training. Participants were randomly assigned to the Placebo (PLA), Soluble Milk Protein (SMP, with fast digestion rate) or Micellar Casein (MC, with slow digestion rate) group. During the 10-week training period, participants were instructed to take 30 g of the placebo or protein twice a day, or three times on training days. Tests were performed on quadriceps muscles at inclusion (PRE), after 4 weeks (MID) and after 10 weeks (POST) of training. They included muscle endurance (maximum number of repetitions during leg extensions using 70% of the individual maximal load), fatigue (decrease in muscle power after the endurance test), strength, power and muscle thickness. Muscle fatigue was significantly lower (P < 0.05) in the SMP group at MID and POST (-326.8 ± 114.1 W and -296.6 ± 130.1 W, respectively) as compared with PLA (-439.2 ± 153.9 W and -479.2 ± 138.1 W, respectively) and MC (-415.1 ± 165.1 W and -413.7 ± 139.4 W, respectively). Increases in maximal muscle power, strength, endurance and thickness were not statistically different between groups. The present study demonstrated that protein composition has a large influence on muscular performance after prolonged resistance training. More specifically, as compared with placebo or micellar casein, soluble milk protein (fast digestible) appeared to significantly reduce muscle fatigue induced by intense resistance exercise.

Life Prediction of Fretting Fatigue with Advanced Surface Treatments (Preprint)

DTIC Science & Technology

2006-05-01

surfaces and not the fretting pads. The chosen coatings included DLC, Ni-B, Molybdenum, and Nitride. These 4 coatings, their application to the titanium ...Article Preprint 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 4 . TITLE AND SUBTITLE LIFE PREDICTION OF FRETTING FATIGUE WITH ADVANCED SURFACE...TREATMENTS (PREPRINT) 5c. PROGRAM ELEMENT NUMBER N/A 5d. PROJECT NUMBER M02R 5e. TASK NUMBER 30 6 . AUTHOR(S) Patrick J. Golden and Michael

CARES/LIFE Ceramics Analysis and Reliability Evaluation of Structures Life Prediction Program

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Powers, Lynn M.; Janosik, Lesley A.; Gyekenyesi, John P.

2003-01-01

This manual describes the Ceramics Analysis and Reliability Evaluation of Structures Life Prediction (CARES/LIFE) computer program. The program calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/or proof test loading. CARES/LIFE is an extension of the CARES (Ceramic Analysis and Reliability Evaluation of Structures) computer program. The program uses results from MSC/NASTRAN, ABAQUS, and ANSYS finite element analysis programs to evaluate component reliability due to inherent surface and/or volume type flaws. CARES/LIFE accounts for the phenomenon of subcritical crack growth (SCG) by utilizing the power law, Paris law, or Walker law. The two-parameter Weibull cumulative distribution function is used to characterize the variation in component strength. The effects of multiaxial stresses are modeled by using either the principle of independent action (PIA), the Weibull normal stress averaging method (NSA), or the Batdorf theory. Inert strength and fatigue parameters are estimated from rupture strength data of naturally flawed specimens loaded in static, dynamic, or cyclic fatigue. The probabilistic time-dependent theories used in CARES/LIFE, along with the input and output for CARES/LIFE, are described. Example problems to demonstrate various features of the program are also included.

Early Experience with a Brief, Multimodal, Multidisciplinary Treatment Program for Fibromyalgia

PubMed Central

Vincent, Ann; Whipple, Mary O.; Oh, Terry H.; Guderian, Janet A.; Barton, Debra L.; Luedtke, Connie A.

2014-01-01

Fibromyalgia is a complex, heterogeneous disorder for which a multidisciplinary individualized approach is currently advocated. We executed a 1 week multidisciplinary fibromyalgia clinical program with 7 patients, based on our previous experience with our existing 1.5 day multidisciplinary fibromyalgia program that has demonstrated both short- and long-term benefits. The current expanded program was not designed as a clinical study, but rather as a clinical feasibility assessment and was multidisciplinary in nature, with cognitive behavioral therapy, activity pacing and graded exercise therapy as major components. We assessed changes in individual patients at 1 week and 3 months following the program utilizing validated self-report measures of pain, fatigue, and self-efficacy. All patients indicated at least small improvements in pain and physical symptoms both at 1 week and 3 months and all but one patient showed improvement in self-efficacy at 1 week and 3 months. Similar trends were observed for fatigue. Based on our early clinical experience, we conclude that the 1 week multidisciplinary fibromyalgia program is logistically feasible and has potential for clinical efficacy. Further research is needed and is planned to test the clinical efficacy of this program and compare it with other interventions. PMID:24315246

Case Studies of Fatigue Life Improvement Using Low Plasticity Burnishing in Gas Turbine Engine Applications

NASA Technical Reports Server (NTRS)

Prevey, Paul S.; Shepard, Michael; Ravindranath, Ravi A.; Gabb, Timothy

2003-01-01

Surface enhancement technologies such as shot peening, laser shock peening (LSP), and low plasticity burnishing (LPB) can provide substantial fatigue life improvement. However, to be effective, the compressive residual stresses that increase fatigue strength must be retained in service. For successful integration into turbine design, the process must be affordable and compatible with the manufacturing environment. LPB provides thermally stable compression of comparable magnitude and even greater depth than other methods, and can be performed in conventional machine shop environments on CNC machine tools. LPB provides a means to extend the fatigue lives of both new and legacy aircraft engines and ground-based turbines. Improving fatigue performance by introducing deep stable layers of compressive residual stress avoids the generally cost prohibitive alternative of modifying either material or design. The X-ray diffraction based background studies of thermal and mechanical stability of surface enhancement techniques are briefly reviewed, demonstrating the importance of minimizing cold work. The LPB process, tooling, and control systems are described. An overview of current research programs conducted for engine OEMs and the military to apply LPB to a variety of engine and aging aircraft components are presented. Fatigue performance and residual stress data developed to date for several case studies are presented including: * The effect of LPB on the fatigue performance of the nickel based super alloy IN718, showing fatigue benefit of thermal stability at engine temperatures. * An order of magnitude improvement in damage tolerance of LPB processed Ti-6-4 fan blade leading edges. * Elimination of the fretting fatigue debit for Ti-6-4 with prior LPB. * Corrosion fatigue mitigation with LPB in Carpenter 450 steel. *Damage tolerance improvement in 17-4PH steel. Where appropriate, the performance of LPB is compared to conventional shot peening after exposure to engine operating temperatures.

Space Shuttle Crawler Transporter Vibration Analysis in Support of Rollout Fatigue Load Spectra Verification Program

NASA Technical Reports Server (NTRS)

Margasahayam, Ravi N.; Meyer, Karl A.; Nerolich, Shaun M.; Burton, Roy C.; Gosselin, Armand M.

2004-01-01

The Crawler Transporter (CT), designed and built for the Apollo Program in the 1960's and surpassing its initial operational life, has become an integral part of the Space Shuttle Program (SSP). The CT transports the Space Shuttle Vehicle (SSV) stack, atop the Mobile Launch Platform (MLP), from the Vehicle Assembly Building (VAB) to the launch pad. This support structure provides hydraulic jacking, leveling and load equalization for the 12 million pound stack on its 3.5-5.0 mile rollout to the launch pad. Major elements of the SSV, consisting of the orbiter, solid rocket boosters (SRB) and external tank (ET) have required fatigue analyses as part of the mission life certification. Compared to rollout vibration, the SSV sees relatively high vibration loads during launch, ascent, descent and landing phases of the mission. Although preliminary measured SRB vibration levels during rollout were of low amplitude and frequency, the duration of the rollout phase is typically high, from 5-6 hours. As part of an expanded mission life assessment, additional certification effort was initiated to define fatigue load spectra for rollout. This study addresses the CT vibration analyses in support of the rollout fatigue study. Structural models developed for modal and vibration analyses were used to identify unique CT, CT/MLP and CT/MLP/SRB vibration characteristics for comparison to instrumented rollout tests. Whereas the main structural and vibration characteristics of the SSV are well defined, minimum analytical and vibration test data on the Crawler Transporter were available. Unique vibration characteristics of the CT are attributable to the drive mechanism, hydraulic jacking system, structural framing and the CT-to-MLP support pad restraints. Initial tests performed on the CT/MLP/SRB configuration showed reasonable correlation with predicted mode shapes and frequencies.

Effectiveness of a tailored neck training program on neck strength, movement, and fatigue in under-19 male rugby players: a randomized controlled pilot study.

PubMed

Barrett, Matthew D; McLoughlin, Terence F; Gallagher, Kieran R; Gatherer, Don; Parratt, Michael Tr; Perera, Jonathan R; Briggs, Tim Wr

2015-01-01

To investigate the effect of a tailored neck muscle conditioning program on neck muscle strength, neck muscle fatigue, and range of neck movement in 16-18-year-old male rugby players. Thirty-four male rugby players were divided into forward and back playing positions and randomized within these groups. Seventeen players were randomly assigned to each group. The test group was given a tailored 6-week exercise regime based on their baseline measurements to be performed three times a week in addition to their normal training and playing. The control group trained and played as normal. The outcome measures used were cervical spine range of movement, neck strength, and neck muscle fatigability. There were no clinically relevant statistically significant differences between the two groups. Trends identified between the two groups suggest that a tailored neck exercise program increases neck strength, particularly neck extension, and increases resistance to fatigue, as well as influencing right- and left-sided neck muscle balance. A reduction in range of movement was also demonstrated in the test group. There was a great deal of variability in range of movement and strength within this age group. No previously undiagnosed neck conditions were detected, and there were no adverse events reported. This study has shown that neck strength, range of movement, and susceptibility of the neck muscles to fatigue can be influenced using a focused neck training regime. It forms an important basis for a larger, multicenter study to ensure the neck is given due attention in rugby training and receives the same focus of conditioning as other parts of the body.

A computer program incorporating fatigue and fracture criteria in the preliminary design of transport aircraft: An evaluation

NASA Technical Reports Server (NTRS)

Berger, P. E.; Thornton, E. A.

1976-01-01

The APAS program a multistation structural synthesis procedure developed to evaluate material, geometry, and configuration with various design criteria usually considered for the primary structure of transport aircraft is described and evaluated. Recommendations to improve accuracy and extend the capabilities of the APAS program are given. Flow diagrams are included.

Crack Growth Simulation and Residual Strength Prediction in Airplane Fuselages

NASA Technical Reports Server (NTRS)

Chen, Chuin-Shan; Wawrzynek, Paul A.; Ingraffea, Anthony R.

1999-01-01

The objectives were to create a capability to simulate curvilinear crack growth and ductile tearing in aircraft fuselages subjected to widespread fatigue damage and to validate with tests. Analysis methodology and software program (FRANC3D/STAGS) developed herein allows engineers to maintain aging aircraft economically, while insuring continuous airworthiness, and to design more damage-tolerant aircraft for the next generation. Simulations of crack growth in fuselages were described. The crack tip opening angle (CTOA) fracture criterion, obtained from laboratory tests, was used to predict fracture behavior of fuselage panel tests. Geometrically nonlinear, elastic-plastic, thin shell finite element crack growth analyses were conducted. Comparisons of stress distributions, multiple stable crack growth history, and residual strength between measured and predicted results were made to assess the validity of the methodology. Incorporation of residual plastic deformations and tear strap failure was essential for accurate residual strength predictions. Issue related to predicting crack trajectory in fuselages were also discussed. A directional criterion, including T-stress and fracture toughness orthotropy, was developed. Curvilinear crack growth was simulated in coupon and fuselage panel tests. Both T-stress and fracture toughness orthotropy were essential to predict the observed crack paths. Flapping of fuselages were predicted. Measured and predicted results agreed reasonable well.

Human performance modeling for system of systems analytics :soldier fatigue.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawton, Craig R.; Campbell, James E.; Miller, Dwight Peter

2005-10-01

The military has identified Human Performance Modeling (HPM) as a significant requirement and challenge of future systems modeling and analysis initiatives as can be seen in the Department of Defense's (DoD) Defense Modeling and Simulation Office's (DMSO) Master Plan (DoD 5000.59-P 1995). To this goal, the military is currently spending millions of dollars on programs devoted to HPM in various military contexts. Examples include the Human Performance Modeling Integration (HPMI) program within the Air Force Research Laboratory, which focuses on integrating HPMs with constructive models of systems (e.g. cockpit simulations) and the Navy's Human Performance Center (HPC) established in Septembermore » 2003. Nearly all of these initiatives focus on the interface between humans and a single system. This is insufficient in the era of highly complex network centric SoS. This report presents research and development in the area of HPM in a system-of-systems (SoS). Specifically, this report addresses modeling soldier fatigue and the potential impacts soldier fatigue can have on SoS performance.« less

TS-SRP/PACK - COMPUTER PROGRAMS TO CHARACTERIZE ALLOYS AND PREDICT CYCLIC LIFE USING THE TOTAL STRAIN VERSION OF STRAINRANGE PARTITIONING

NASA Technical Reports Server (NTRS)

Saltsman, J. F.

1994-01-01

TS-SRP/PACK is a set of computer programs for characterizing and predicting fatigue and creep-fatigue resistance of metallic materials in the high-temperature, long-life regime for isothermal and nonisothermal fatigue. The programs use the total strain version of the Strainrange Partitioning (TS-SRP). The user should be thoroughly familiar with the TS-SRP method before attempting to use any of these programs. The document for this program includes a theory manual as well as a detailed user's manual with a tutorial to guide the user in the proper use of TS-SRP. An extensive database has also been developed in a parallel effort. This database is an excellent source of high-temperature, creep-fatigue test data and can be used with other life-prediction methods as well. Five programs are included in TS-SRP/PACK along with the alloy database. The TABLE program is used to print the datasets, which are in NAMELIST format, in a reader friendly format. INDATA is used to create new datasets or add to existing ones. The FAIL program is used to characterize the failure behavior of an alloy as given by the constants in the strainrange-life relations used by the total strain version of SRP (TS-SRP) and the inelastic strainrange-based version of SRP. The program FLOW is used to characterize the flow behavior (the constitutive response) of an alloy as given by the constants in the flow equations used by TS-SRP. Finally, LIFE is used to predict the life of a specified cycle, using the constants characterizing failure and flow behavior determined by FAIL and FLOW. LIFE is written in interpretive BASIC to avoid compiling and linking every time the equation constants are changed. Four out of five programs in this package are written in FORTRAN 77 for IBM PC series and compatible computers running MS-DOS and are designed to read data using the NAMELIST format statement. The fifth is written in BASIC version 3.0 for IBM PC series and compatible computers running MS-DOS version 3.10. The executables require at least 239K of memory and DOS 3.1 or higher. To compile the source, a Lahey FORTRAN compiler is required. Source code modifications will be necessary if the compiler to be used does not support NAMELIST input. Probably the easiest revision to make is to use a list-directed READ statement. The standard distribution medium for this program is a set of two 5.25 inch 360K MS-DOS format diskettes. The contents of the diskettes are compressed using the PKWARE archiving tools. The utility to unarchive the files, PKUNZIP.EXE, is included. TS-SRP/PACK was developed in 1992.

Durability evaluation of ceramic components using CARES/LIFE

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Powers, Lynn M.; Janosik, Lesley A.; Gyekenyesi, John P.

1994-01-01

The computer program CARES/LIFE calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/or proof test loading. This program is an extension of the CARES (Ceramics Analysis and Reliability Evaluation of Structures) computer program. CARES/LIFE accounts for the phenomenon of subcritical crack growth (SCG) by utilizing the power law, Paris law, or Walker equation. The two-parameter Weibull cumulative distribution function is used to characterize the variation in component strength. The effects of multiaxial stresses are modeled using either the principle of independent action (PIA), the Weibull normal stress averaging method (NSA), or the Batdorf theory. Inert strength and fatigue parameters are estimated from rupture strength data of naturally flawed specimens loaded in static, dynamic, or cyclic fatigue. Application of this design methodology is demonstrated using experimental data from alumina bar and disk flexure specimens which exhibit SCG when exposed to water.

Durability evaluation of ceramic components using CARES/LIFE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nemeth, N.N.; Janosik, L.A.; Gyekenyesi, J.P.

1996-01-01

The computer program CARES/LIFE calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/or proof test loading. This program is an extension of the CARES (Ceramics Analysis and Reliability Evaluation of Structures) computer program. CARES/LIFE accounts for the phenomenon of subcritical crack growth (SCG) by utilizing the power law, Paris law, or Walker equation. The two-parameter Weibull cumulative distribution function is used to characterize the variation in component strength. The effects of multiaxial stresses are modeled using either the principle of independent action (PIA), the Weibull normal stress averaging method (NSA), or the Batdorf theory. Inert strength andmore » fatigue parameters are estimated from rupture strength data of naturally flawed specimens loaded in static, dynamic, or cyclic fatigue. Application of this design methodology is demonstrated using experimental data from alumina bar and disk flexure specimens, which exhibit SCG when exposed to water.« less

NASALIFE - Component Fatigue and Creep Life Prediction Program

NASA Technical Reports Server (NTRS)

Gyekenyesi, John Z.; Murthy, Pappu L. N.; Mital, Subodh K.

2014-01-01

NASALIFE is a life prediction program for propulsion system components made of ceramic matrix composites (CMC) under cyclic thermo-mechanical loading and creep rupture conditions. Although the primary focus was for CMC components, the underlying methodologies are equally applicable to other material systems as well. The program references empirical data for low cycle fatigue (LCF), creep rupture, and static material properties as part of the life prediction process. Multiaxial stresses are accommodated by Von Mises based methods and a Walker model is used to address mean stress effects. Varying loads are reduced by the Rainflow counting method or a peak counting type method. Lastly, damage due to cyclic loading and creep is combined with Minor's Rule to determine damage due to cyclic loading, damage due to creep, and the total damage per mission and the number of potential missions the component can provide before failure.

Benefits of pulmonary rehabilitation in idiopathic pulmonary fibrosis.

PubMed

Swigris, Jeffrey J; Fairclough, Diane L; Morrison, Marianne; Make, Barry; Kozora, Elizabeth; Brown, Kevin K; Wamboldt, Frederick S

2011-06-01

Information on the benefits of pulmonary rehabilitation (PR) in patients with idiopathic pulmonary fibrosis (IPF) is growing, but PR's effects on certain important outcomes is lacking. We conducted a pilot study of PR in IPF and analyzed changes in functional capacity, fatigue, anxiety, depression, sleep, and health status from baseline to after completion of a standard, 6-week PR program. Six-min walk distance improved a mean ± standard error 202 ± 135 feet (P = .01) from baseline. Fatigue Severity Scale score also improved significantly, declining an average 1.5 ± 0.5 points from baseline. There were trends toward improvement in anxiety, depression, and health status. PR improves functional capacity and fatigue in patients with IPF. (Clinical Trials.gov registration NCT00692796.)

Effects of an individual 12-week community-located "start-to-run" program on physical capacity, walking, fatigue, cognitive function, brain volumes, and structures in persons with multiple sclerosis.

PubMed

Feys, Peter; Moumdjian, Lousin; Van Halewyck, Florian; Wens, Inez; Eijnde, Bert O; Van Wijmeersch, Bart; Popescu, Veronica; Van Asch, Paul

2017-11-01

Exercise therapy studies in persons with multiple sclerosis (pwMS) primarily focused on motor outcomes in mid disease stage, while cognitive function and neural correlates were only limitedly addressed. This pragmatic randomized controlled study investigated the effects of a remotely supervised community-located "start-to-run" program on physical and cognitive function, fatigue, quality of life, brain volume, and connectivity. In all, 42 pwMS were randomized to either experimental (EXP) or waiting list control (WLC) group. The EXP group received individualized training instructions during 12 weeks (3×/week), to be performed in their community aiming to participate in a running event. Measures were physical (VO 2max , sit-to-stand test, Six-Minute Walk Test (6MWT), Multiple Sclerosis Walking Scale-12 (MSWS-12)) and cognitive function (Rao's Brief Repeatable Battery (BRB), Paced Auditory Serial Attention Test (PASAT)), fatigue (Fatigue Scale for Motor and Cognitive Function (FSMC)), quality of life (Multiple Sclerosis Impact Scale-29 (MSIS-29)), and imaging. Brain volumes and diffusion tensor imaging (DTI) were quantified using FSL-SIENA/FIRST and FSL-TBSS. In all, 35 pwMS completed the trial. Interaction effects in favor of the EXP group were found for VO 2max , sit-to-stand test, MSWS-12, Spatial Recall Test, FSMC, MSIS-29, and pallidum volume. VO 2max improved by 1.5 mL/kg/min, MSWS-12 by 4, FSMC by 11, and MSIS-29 by 14 points. The Spatial Recall Test improved by more than 10%. Community-located run training improved aerobic capacity, functional mobility, visuospatial memory, fatigue, and quality of life and pallidum volume in pwMS.

Exercise prescription for patients with multiple sclerosis; potential benefits and practical recommendations.

PubMed

Halabchi, Farzin; Alizadeh, Zahra; Sahraian, Mohammad Ali; Abolhasani, Maryam

2017-09-16

Multiple sclerosis (MS) can result in significant mental and physical symptoms, specially muscle weakness, abnormal walking mechanics, balance problems, spasticity, fatigue, cognitive impairment and depression. Patients with MS frequently decrease physical activity due to the fear from worsening the symptoms and this can result in reconditioning. Physicians now believe that regular exercise training is a potential solution for limiting the reconditioning process and achieving an optimal level of patient activities, functions and many physical and mental symptoms without any concern about triggering the onset or exacerbation of disease symptoms or relapse. Appropriate exercise can cause noteworthy and important improvements in different areas of cardio respiratory fitness (Aerobic fitness), muscle strength, flexibility, balance, fatigue, cognition, quality of life and respiratory function in MS patients. Aerobic exercise training with low to moderate intensity can result in the improvement of aerobic fitness and reduction of fatigue in MS patients affected by mild or moderate disability. MS patients can positively adapt to resistance training which may result in improved fatigue and ambulation. Flexibility exercises such as stretching the muscles may diminish spasticity and prevent future painful contractions. Balance exercises have beneficial effects on fall rates and better balance. Some general guidelines exist for exercise recommendation in the MS population. The individualized exercise program should be designed to address a patient's chief complaint, improve strength, endurance, balance, coordination, fatigue and so on. An exercise staircase model has been proposed for exercise prescription and progression for a broad spectrum of MS patients. Exercise should be considered as a safe and effective means of rehabilitation in MS patients. Existing evidence shows that a supervised and individualized exercise program may improve fitness, functional capacity and quality of life as well as modifiable impairments in MS patients.

75 FR 76345 - Risk Reduction Program

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-08

... Management Plan Each RRPP must include a Fatigue Management Plan (FMP) that will be designed to reduce the... organizations to develop voluntary proactive safety programs designed to improve railroad safety and build... contractors. A railroad's RRPP may be required to specify how the railroad will periodically review the design...

Reducing Uncertainty in Fatigue Life Limits of Turbine Engine Alloys (Preprint)

DTIC Science & Technology

2012-08-01

materials and components designs Conclusions This paper used electropolished specimens of the high-strength titanium alloy Ti-6Al- 2Sn-4Zr-6Mo to...From - To) August 2012 Technical Paper 1 July 2012 – 1 August 2012 4 . TITLE AND SUBTITLE REDUCING UNCERTAINTY IN FATIGUE LIFE LIMITS OF TURBINE...ENGINE ALLOYS (PREPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6 . AUTHOR(S) J.M. Larsen, C.J

A life prediction model for laminated composite structural components

NASA Technical Reports Server (NTRS)

Allen, David H.

1990-01-01

A life prediction methodology for laminated continuous fiber composites subjected to fatigue loading conditions was developed. A summary is presented of research completed. A phenomenological damage evolution law was formulated for matrix cracking which is independent of stacking sequence. Mechanistic and physical support was developed for the phenomenological evolution law proposed above. The damage evolution law proposed above was implemented to a finite element computer program. And preliminary predictions were obtained for a structural component undergoing fatigue loading induced damage.

Vacuum Levels Needed to Simulate Internal Fatigue Crack Growth in Titanium Alloys and Nickel-base Superalloys: Thermodynamic Considerations

DTIC Science & Technology

2012-03-01

AFRL-RX-WP-TP-2012-0250 VACUUM LEVELS NEEDED TO SIMULATE INTERNAL FATIGUE CRACK GROWTH IN TITANIUM ALLOYS AND NICKEL - BASE SUPERALLOYS...TITANIUM ALLOYS AND NICKEL - BASE SUPERALLOYS: THERMODYNAMIC CONSIDERATIONS (PREPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM...surface growth in Ti- alloys and Ni - base superalloys. Even with the highest vacuum level attained using “state-of-the-art” pumps, it is unclear if

Solving the surgeon ergonomic crisis with surgical exosuit.

PubMed

Liu, Shanglei; Hemming, Daniel; Luo, Ran B; Reynolds, Jessica; Delong, Jonathan C; Sandler, Bryan J; Jacobsen, Garth R; Horgan, Santiago

2018-01-01

The widespread adoption of laparoscopic surgery has put new physical demands on the surgeon leading to increased musculoskeletal disorders and injuries. Shoulder, back, and neck pains are among the most common complaints experienced by laparoscopic surgeons. Here, we evaluate the feasibility and efficacy of a non-intrusive progressive arm support exosuit worn by surgeons under the sterile gown to reduce pain and fatigue during surgery. This is a prospective randomized crossover study approved by the Internal Review Board (IRB). The study involves three phases of testing. In each phase, general surgery residents or attendings were randomized to wearing the surgical exosuit at the beginning or at the crossover point. The first phase tests for surgeon manual dexterity wearing the device using the Minnesota Dexterity test, the Purdue Pegboard test, and the Fundamentals of Laparoscopic Surgery (FLS) modules. The second phase tests the effect of the device on shoulder pain and fatigue while operating the laparoscopic camera. The third phase rates surgeon experience in the operating room between case-matched operating days. Twenty subjects were recruited for this study. Surgeons had the similar dexterity scores and FLS times whether or not they wore the exosuit (p value ranges 0.15-0.84). All exosuit surgeons completed 15 min of holding laparoscopic camera compared to three non-exosuit surgeons (p < 0.02). Exosuit surgeons experienced significantly less fatigue at all time periods and arm pain (3.11 vs 5.88, p = 0.019) at 10 min. Surgeons wearing the exosuit during an operation experienced significant decrease in shoulder pain and 85% of surgeons reported some form of pain reduction at the end of the operative day. The progressive arm support exosuit can be a minimally intrusive device that laparoscopic surgeons wear to reduce pain and fatigue of surgery without significantly interfering with operative skills or manual dexterity.

Relationship of fatigue and exercise capacity with emotional and physical state in patients with coronary artery disease admitted for rehabilitation program.

PubMed

Bunevicius, Adomas; Stankus, Albinas; Brozaitiene, Julija; Girdler, Susan S; Bunevicius, Robertas

2011-08-01

The relationship between subjective fatigue, exercise capacity, and symptoms of depression and anxiety in patients with coronary artery disease (CAD) needs to be specified. In this cross-sectional study, a total of 1,470 (64% men; mean age 57 ± 11 years) consecutive CAD patients admitted for cardiac rehabilitation after treatment of acute cardiac events were evaluated for demographic characteristics, for past and current diagnosis and treatment, for New York Heart Association (NYHA) class, for symptoms of depression and for symptoms of anxiety using the Hospital Anxiety and Depression Scale, and for subjective fatigue using the Multidimensional Fatigue Inventory. On the next day, all patients underwent exercise capacity evaluation using a standard bicycle ergometer testing procedure. In univariate regression analyses, there was the strongest positive association between scores on all Multidimensional Fatigue Inventory subscales and scores on the Hospital Anxiety and Depression Scale depression and anxiety subscales and between exercise capacity and NYHA class. Multivariate regression analyses revealed that symptoms of depression were the strongest positive determinants of all dimensions of subjective fatigue and, together with other significant variables, accounted for 17% to 29% of the variance. However, neither depressive nor anxious symptoms were significant determinants of exercise capacity. The association between subjective fatigue and exercise capacity and vice versa was minimal. Subjective fatigue in CAD patients is strongly related to symptoms of depression and symptoms of anxiety. In contrast, exercise capacity in CAD patients is strongly related to NYHA functional class, with no relationship to symptoms of depression and anxiety. Copyright © 2011 Mosby, Inc. All rights reserved.

Effects of Fatigue on Throwing Performance in Experienced Team Handball Players

PubMed Central

Nuño, Alberto; van den Tillaar, Roland; Guisado, Rafael; Martín, Ignacio; Martinez, Isidoro; Chirosa, Luis J.

2016-01-01

Abstract The purpose of this study was to investigate the effect of central and peripheral physiological fatigue on throwing accuracy and ball release velocity in team handball. Twenty male subjects (age 24.7 ± 3.9 yrs, body mass 88.5 ± 5.0 kg, body height 1.86 ± 0.05 m, training experience 12.7 ± 3.8 yrs) from one handball team participated in this study. The participants completed four sets of eight laps of a circuit that consisted of specific team handball drills/exercises, with decreasing recovery times between the laps in each set in order to induce physiological fatigue. Duration of the recovery intervals determined the description of the effort made in each set: “light" (80 s recovery between laps), “moderate" (40 s), “hard" (20 s) and “very hard" (10 s). A heart rate, concentration of lactate in blood and the rate of perceived exertion (RPE) were recorded. Ball velocity and accuracy were measured after each set and they both decreased during a fatigue protocol. However, accuracy only decreased significantly in the end of the protocol, while ball release was already affected after the first round of the protocol. The results substantiate the initial hypothesis and confirm that both throwing accuracy and ball release velocity decrease significantly as physiological fatigue increases. These variables began to decrease when the fatigue quantification values were high or very high. The findings can be used by coaches to develop training programs to teach players how to identify fatigue thresholds and combat the effects of fatigue through decision-making skills at critical game moments. PMID:28031762

A Randomized Controlled Trial of Home-Based Exercise for Cancer-Related Fatigue in Women during and after Chemotherapy with or without Radiation Therapy

PubMed Central

Dodd, Marylin J.; Cho, Maria H.; Miaskowski, Christine; Painter, Patricia L.; Paul, Steven M.; Cooper, Bruce A.; Duda, John; Krasnoff, Joanne; Bank, Kayee A.

2010-01-01

Background Few studies have evaluated an individualized home-based exercise prescription during and after cancer treatment. Objective The purpose was to evaluate the effectiveness of a home-based exercise training intervention, the PRO-SELF FATIGUE CONTROL PROGRAM on the management of cancer related fatigue. Interventions/Methods Participants (N=119) were randomized into one of three groups: Group 1 (EE) received the exercise prescription throughout the study; Group 2 (CE) received their exercise prescription after completing cancer treatment; Group 3 (CC) received usual care. Patients completed the Piper Fatigue Scale, General Sleep Disturbance Scale, Center for Epidemiological Studies-Depression scale, and Worst Pain Intensity Scale. Results All groups reported mild fatigue levels, sleep disturbance and mild pain, but not depression. Using multilevel regression analysis significant linear and quadratic trends were found for change in fatigue and pain (i.e., scores increased, then decreased over time). No group differences were found in the changing scores over time. A significant quadratic effect for the trajectory of sleep disturbance was found, but no group differences were detected over time. No significant time or group effects were found for depression. Conclusions Our home-based exercise intervention had no effect on fatigue or related symptoms associated with cancer treatment. The optimal timing of exercise remains to be determined. Implications for practice Clinicians need to be aware that some physical activity is better than none, and there is no harm in exercise as tolerated during cancer treatment. Further analysis is needed to examine the adherence to exercise. More frequent assessments of fatigue, sleep disturbance, depression, and pain may capture the effect of exercise. PMID:20467301

Integrated technology rotor/flight research rotor concept definition study

NASA Technical Reports Server (NTRS)

Carlson, R. G.; Beno, E. A.; Ulisnik, H. D.

1983-01-01

As part of the Integrated Technology Rotor/Flight Research Rotor (ITR/FRR) Program a number of advanced rotor system designs were conceived and investigated. From these, several were chosen that best meet the started ITR goals with emphasis on stability, reduced weight and hub drag, simplicity, low head moment stiffness, and adequate strength and fatigue life. It was concluded that obtaining low hub moment stiffness was difficult when only the blade flexibility of bearingless rotor blades is considered, unacceptably low fatigue life being the primary problem. Achieving a moderate hub moment stiffness somewhat higher than state of the art articulated rotors in production today is possible within the fatigue life constraint. Alternatively, low stiffness is possible when additional rotor elements, besides the blades themselves, provide part of the rotor flexibility. Two primary designs evolved as best meeting the general ITR requirements that presently exist. An I shaped flexbeam with an external torque tube can satisfy the general goals but would have either higher stiffness or reduced fatigue life. The elastic gimbal rotor can achieve a better combination of low stiffness and high fatigue life but would be a somewhat heavier design and possibly exhibit a higher risk of aeromechanical instability.

In-air and pressurized water reactor environment fatigue experiments of 316 stainless steel to study the effect of environment on cyclic hardening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohanty, Subhasish; Soppet, William K.; Majumdar, Saurindranath

Argonne National Laboratory (ANL), under the sponsorship of Department of Energy’s Light Water Reactor Sustainability (LWRS) program, is trying to develop a mechanistic approach for more accurate life estimation of LWR components. In this context, ANL has conducted many fatigue experiments under different test and environment conditions on type 316 stainless steel (316SS) material which is widely used in the US reactors. Contrary to the conventional S~N curve based empirical fatigue life estimation approach, the aim of the present DOE sponsored work is to develop an understanding of the material ageing issues more mechanistically (e.g. time dependent hardening and softening)more » under different test and environmental conditions. Better mechanistic understanding will help develop computer-based advanced modeling tools to better extrapolate stress-strain evolution of reactor components under multi-axial stress states and hence help predict their fatigue life more accurately. In this paper (part-I) the fatigue experiments under different test and environment conditions and related stress-strain results for 316 SS are discussed. In a second paper (part-II) the related evolutionary cyclic plasticity material modeling techniques and results are discussed.« less

Nurse managers' perception of night-shift napping: A cross-sectional survey.

PubMed

Dalky, Heyam F; Raeda, AbuAlRub F; Esraa, Aldalqamouni A

2017-10-04

Night-shift work often results in sleep deprivation, and this in turn results in fatigue that jeopardizes both nurse and patient safety. Napping is considered a viable deterrent to fatigue, yet hospital administration has been slow to adopt napping. To identify nurse managers' knowledge and approval of napping practices for nurses on night shifts. Nurse managers at nine Jordanian hospitals (n = 129) were surveyed using an Arabic version of a questionnaire previously used in a Canadian study. Descriptive statistics were used to describe results, and a one-way ANOVA was used to determine if relationships existed among nurse manager's approval of napping and nurse demographic characteristics. The majority of nurse managers (61%) knew nurses were napping during breaks. However, the managers reported there was no written policy for napping. A majority thought there were more benefits to napping than drawbacks. Some 55% of nurse managers recognized fatigue as a cause of errors or incidents regarding patient safety, and 40% perceived fatigue to be a factor in staff injuries. This study supports an urgent need for shared responsibility among nursing administration, and bedside nurses to develop evidence-based programs to counteract the effects of nurse fatigue. © 2017 Wiley Periodicals, Inc.

Fatigue and fracture assessment of cracks in steel elements using acoustic emission

NASA Astrophysics Data System (ADS)

Nemati, Navid; Metrovich, Brian; Nanni, Antonio

2011-04-01

Single edge notches provide a very well defined load and fatigue crack size and shape environment for estimation of the stress intensity factor K, which is not found in welded elements. ASTM SE(T) specimens do not appear to provide ideal boundary conditions for proper recording of acoustic wave propagation and crack growth behavior observed in steel bridges, but do provide standard fatigue crack growth rate data. A modified versions of the SE(T) specimen has been examined to provide small scale specimens with improved acoustic emission(AE) characteristics while still maintaining accuracy of fatigue crack growth rate (da/dN) versus stress intensity factor (ΔK). The specimens intend to represent a steel beam flange subjected to pure tension, with a surface crack growing transverse to a uniform stress field. Fatigue test is conducted at low R ratio. Analytical and numerical studies of stress intensity factor are developed for single edge notch test specimens consistent with the experimental program. ABAQUS finite element software is utilized for stress analysis of crack tips. Analytical, experimental and numerical analysis were compared to assess the abilities of AE to capture a growing crack.

Fatigue life of high-speed ball bearings with silicon nitride balls

NASA Technical Reports Server (NTRS)

Parker, R. J.; Zaretsky, E. V.

1974-01-01

Hot-pressed silicon nitride was evaluated as a rolling-element bearing material. The five-ball fatigue tester was used to test 12.7-mm- diameter silicon nitride balls at maximum Hertz stresses ranging from 4.27 x 10 to the 9th power n/sq m to 6.21 x 10 to the 9th power n/sq m at a race temperature of 328K. The fatigue life of NC-132 hot-pressed silicon nitride was found to be equal to typical bearing steels and much greater than other ceramic or cermet materials at the same stress levels. A digital computer program was used to predict the fatigue life of 120-mm- bore angular-contact ball bearings containing either steel or silicon nitride balls. The analysis indicates that there is no improvement in the lives of bearings of the same geometry operating at DN values from 2 to 4 million where silicon nitride balls are used in place of steel balls.

Jet lag and travel fatigue: a comprehensive management plan for sport medicine physicians and high-performance support teams.

PubMed

Samuels, Charles H

2012-05-01

The impact of transcontinental travel and high-volume travel on athletes can result in physiologic disturbances and a complicated set of physical symptoms. Jet lag and travel fatigue have been identified by athletes, athletic trainers, coaches, and physicians as important but challenging problems that could benefit from practical solutions. Currently, there is a culture of disregard and lack of knowledge regarding the negative effects of jet lag and travel fatigue on the athlete's well-being and performance. In addition, the key physiologic metric (determination of the human circadian phase) that guides jet lag treatment interventions is elusive and thus limits evidence-based therapeutic advice. A better understanding of preflight, in-flight, and postflight management options, such as use of melatonin or the judicious application of sedatives, is important for the sports clinician to help athletes limit fatigue symptoms and maintain optimal performance. The purpose of this article was to provide a practical applied method of implementing a travel management program for athletic teams.

[Effects of aroma self-foot reflexology massage on stress and immune responses and fatigue in middle-aged women in rural areas].

PubMed

Kim, Ja Ok; Kim, In Sook

2012-10-01

This study was done to examine the effects of aroma self-foot reflexology massage on stress and immune responses and fatigue in middle-aged women in rural areas. The study was a nonequivalent control group pre-post test design. The participants were 52 middle-aged women from rural areas of which 26 were assigned to the experimental group and 26 to the control group. Data were collected from July to September, 2011 and analyzed using SPSS Win 17.0 version program. The intervention was conducted 3 times a week for six weeks. There were significant differences in reported perceived stress, systolic blood pressure, diastolic blood pressure and fatigue between the two groups. However, the issue of salivary cortisol and immune response were not significant. Aroma self-foot reflexology massage can be utilized as an effective intervention for perceived stress, systolic blood pressure, diastolic blood pressure and fatigue in middle-aged woman in rural areas.

Distributed stimulation increases force elicited with functional electrical stimulation

NASA Astrophysics Data System (ADS)

Buckmire, Alie J.; Lockwood, Danielle R.; Doane, Cynthia J.; Fuglevand, Andrew J.

2018-04-01

Objective. The maximum muscle forces that can be evoked using functional electrical stimulation (FES) are relatively modest. The reason for this weakness is not fully understood but could be partly related to the widespread distribution of motor nerve branches within muscle. As such, a single stimulating electrode (as is conventionally used) may be incapable of activating the entire array of motor axons supplying a muscle. Therefore, the objective of this study was to determine whether stimulating a muscle with more than one source of current could boost force above that achievable with a single source. Approach. We compared the maximum isometric forces that could be evoked in the anterior deltoid of anesthetized monkeys using one or two intramuscular electrodes. We also evaluated whether temporally interleaved stimulation between two electrodes might reduce fatigue during prolonged activity compared to synchronized stimulation through two electrodes. Main results. We found that dual electrode stimulation consistently produced greater force (~50% greater on average) than maximal stimulation with single electrodes. No differences, however, were found in the fatigue responses using interleaved versus synchronized stimulation. Significance. It seems reasonable to consider using multi-electrode stimulation to augment the force-generating capacity of muscles and thereby increase the utility of FES systems.

Sleep and the use of energy products in a combat environment.

PubMed

Waits, Wendi M; Ganz, Michael B; Schillreff, Theresa; Dell, Peter J

2014-01-01

The use of energy products appears to be widespread among deployed personnel, presumably to combat fatigue and sleep deprivation. However, these products have been associated with unpleasant side effects and adverse events, including insomnia, mood swings, fatigue, cardiac arrest, and even death. To quantify the sleep habits and energy products used among deployed service members in Afghanistan from 2010-2011. Participants completed an anonymous survey querying their demographic information, sleep habits, combat exposure, and energy product use. Respondent data: 83% experienced some degree of insomnia; 28% were using a prescription or over-the-counter sleep aid; 81% reported using at least one energy product daily. The most frequently consumed energy products were caffeinated coffee and soda. Only 4 energy products were used more frequently during deployment than prior to deployment: Rip-It, Tiger, Hydroxycut, and energy drink powders. On average, respondents who increased their use consumed only 2 more servings per week during deployment than they had prior to deployment. Only degree of combat exposure, not quantity of energy products consumed, predicted degree of insomnia. Energy product consumption by service members during deployment was not dramatically different than predeployment and was not associated with insomnia.

What kind of diagnosis in a case of mobbing: post-traumatic stress disorder or adjustment disorder?

PubMed

Signorelli, Maria Salvina; Costanzo, Maria Cristina; Cinconze, Maria; Concerto, Carmen

2013-06-11

Over the last decade a consistent increase in stress-related psychological consequences at the workplace, usually called 'mobbing', has been seen. It claimed physical, psychical and social distress as its victims, leading to an increased incidence of many illnesses, such as psychosomatic disorders (ache, high blood pressure, chronic fatigue and insomnia) and psychiatric disturbances (high level of anxiety, depression and suicidal attempts). It was recently demonstrated that mobbing is significantly widespread among healthcare workers, especially among female nurses. In this report, we illustrate the case of a nurse who, after a brilliant career, underwent mobbing at the workplace, showing depression, anxiety and sleep disorders that required hospitalisation and a substantial intervention.

[Difficulties with diagnosis of fibromyalgia: case report].

PubMed

Atarowska, Magdalena; Samborski, Włodzimierz

2006-01-01

We present a case of a 33-year-old woman with nonspecific systemic symptoms (fatigue, weakness), widespread pains, sleep disorders, morning stiffness, accompanied by symptoms from the autonomic nervous system (chest pain, digestive tract disorders, hyperesthesia of the skin, dizziness, paresthesia with a feeling of coldness in hands and feet, excessive sweating, breath problems, palpitations). The diagnostic process was difficult and it took a long time to establish the diagnosis partly because of problems in cooperating with this patient. During several years, the woman was hospitalized at several specialist departments, underwent many consultations, laboratory tests, and imaging studies. Finally, fibromyalgia was diagnosed. Treatment was implemented with good results improving the quality of life of this patient.

Successes of a national study of the Chronic Disease Self-Management Program: meeting the triple aim of health care reform.

PubMed

Ory, Marcia G; Ahn, SangNam; Jiang, Luohua; Smith, Matthew Lee; Ritter, Philip L; Whitelaw, Nancy; Lorig, Kate

2013-11-01

Emerging health care reform initiatives are of growing importance amidst concerns about providing care to increasing numbers of adults with multiple chronic conditions. Evidence-based self-management strategies are recognized as central to managing a variety of chronic diseases by improving the medical, emotional, and social role management demands of chronic conditions. To examine the effectiveness of the Chronic Disease Self-Management Program (CDSMP) among a national sample of participants organized around the Triple Aim goals of better health, better health care, and better value in terms of reduced health care utilization. Utilizing data collected from small-group CDSMP workshops, baseline, 6-month, and 12-month assessments were examined using 3 types of mixed-effects models to provide unbiased estimates of intervention effects. Data were analyzed from 1170 community-dwelling CDSMP participants. Triple Aim-related outcome measures: better health (eg, self-reported health, pain, fatigue, depression), better health care (eg, patient-physician communication, medication compliance, confidence completing medical forms), and better value [eg, reductions in emergency room (ER) visits and hospitalizations in the past 6 mo]. Significant improvements for all better health and better health care outcome measures were observed from baseline to 12-month follow-up. The odds of ER visits significantly reduced from baseline to 12-month follow-up, whereas significant reductions in hospitalization were only observed from baseline to 6-month follow-up. This National Study of CDSMP (National Study) demonstrates the successful translation of CDSMP into widespread practice and its potential for helping the nation achieve the triple aims of health care reform.

Computerized fracture critical and specialized bridge inspection program with NDE applications

NASA Astrophysics Data System (ADS)

Fish, Philip E.

1998-03-01

Wisconsin Department of Transportation implemented a Fracture Critical & Specialized Inspection Program in 1987. The program has a strong emphasis on Nondestructive Testing (NDT). The program is also completely computerized, using laptop computers to gather field data, digital cameras for pictures, and testing equipment with download features. Final inspection reports with detailed information can be delivered within days of the inspection. The program requires an experienced inspection team and qualified personnel. Individuals performing testing must be licensed ASNT (American Society for Nondestructive Testing) Level III and must be licensed Certified Weld Inspectors (American Welding Society). Several critical steps have been developed to assure that each inspection identifies all possible deficiencies that may be possible on a Fracture Critical or Unique Bridge. They include; review of all existing plans and maintenance history; identification of fracture critical members, identification of critical connection details, welds, & fatigue prone details, development of visual and NDE inspection plan; field inspection procedures; and a detailed formal report. The program has found several bridges with critical fatigue conditions which have resulted in replacement or major rehabilitation. In addition, remote monitoring systems have been installed on structures with serious cracking to monitor for changing conditions.

The effect of exercise on fatigue and physical functioning in breast cancer patients during and after treatment and at 6 months follow-up: A meta-analysis.

PubMed

Juvet, L K; Thune, I; Elvsaas, I K Ø; Fors, E A; Lundgren, S; Bertheussen, G; Leivseth, G; Oldervoll, L M

2017-06-01

Breast cancer is the leading cause of cancer in women worldwide. Exercise interventions may improve physical and psychological factors during and after active breast cancer treatment. The aim of this systematic review was to assess the current knowledge regarding the efficacy of physical exercise with respect to fatigue and self-reported physical functioning. Systematic searches in Cochrane Library, Medline, Embase, Cinahl, PsycINFO, AMED and PEDro. After assessing the quality of the studies, we identified 25 randomized controlled trials that included 3418 breast cancer patients. An increase in physical functioning and a decrease in fatigue were observed after a physical exercise intervention, with an SMD of 0.27 (0.12, 0.41) and -0.32 (-0.49, - 0.14), respectively. There were slightly higher improvements in physical functioning and fatigue when the patients received the intervention after adjuvant breast cancer treatment. The 6-month follow-up data showed a small favourable difference for the physical exercise group for both physical functioning and fatigue. This systematic review found that an exercise intervention program can produce short-term improvements in physical functioning and can reduce fatigue in breast cancer patients. However, more studies are needed to confirm the time-dependent observations in this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development and Applications of a Self-Contained, Non-Invasive EVA Joint Angle and Muscle Fatigue Sensor System

NASA Technical Reports Server (NTRS)

Ranniger, C. U.; Sorenson, E. A.; Akin, D. L.

1995-01-01

The University of Maryland Space Systems Laboratory, as a participant in NASA's INSTEP program, is developing a non-invasive, self-contained sensor system which can provide quantitative measurements of joint angles and muscle fatigue in the hand and forearm. The goal of this project is to develop a system with which hand/forearm motion and fatigue metrics can be determined in various terrestrial and zero-G work environments. A preliminary study of the prototype sensor systems and data reduction techniques for the fatigue measurement system are presented. The sensor systems evaluated include fiberoptics, used to measure joint angle, surface electrodes, which measure the electrical signals created in muscle as it contracts; microphones, which measure the noise made by contracting muscle; and accelerometers, which measure the lateral muscle acceleration during contraction. The prototype sensor systems were used to monitor joint motion of the metacarpophalangeal joint and muscle fatigue in flexor digitorum superficialis and flexor carpi ulnaris in subjects performing gripping tasks. Subjects were asked to sustain a 60-second constant-contraction (isometric) exercise and subsequently to perform a repetitive handgripping task to failure. Comparison of the electrical and mechanical signals of the muscles during the different tasks will be used to evaluate the applicability of muscle signal measurement techniques developed for isometric contraction tasks to fatigue prediction in quasi-dynamic exercises. Potential data reduction schemes are presented.

Different fatigue-resistant leg muscles and EMG response during whole-body vibration.

PubMed

Simsek, Deniz

2017-12-01

The purpose of this study was to determine the effects of static whole-body vibration (WBV) on the Electromyograhic (EMG) responses of leg muscles, which are fatigue-resistant in different manner. The study population was divided into two groups according to the values obtained by the Fatigue Index [Group I: Less Fatigue Resistant (LFR), n=11; Group II: More Fatigue Resistant (MFR), n=11]. The repeated electromyographic (EMG) activities of four leg muscles were analyzed the following determinants: (1) frequency (30 Hz, 35 Hz and 40 Hz); (2) stance position (static squat position); (3) amplitude (2 mm and 4 mm) and (4) knee flexion angle (120°), (5) vertical vibration platform. Vibration data were analyzed using Minitab 16 (Minitab Ltd, State College, PA, USA). The significance level was set at p<.05. The study results showed that static WBV stimuli given at different frequencies and amplitudes resulted in a significant increase (p<.05) in compared, the LFR group showed significantly (1) higher rates of quadriceps femoris and hamstring muscle fatigue (p<.05), (2) higher levels of knee extensor and flexor torque (p<.05) and (3) higher percentage increases in EMG activation at higher frequencies (max at 40 Hz) and amplitudes (4 mm) (p<.05). The present study can be used for the optimal prescription of vibration exercise and can serve to guide the development of training programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Study the Cyclic Plasticity Behavior of 508 LAS under Constant, Variable and Grid-Load-Following Loading Cycles for Fatigue Evaluation of PWR Components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohanty, Subhasish; Barua, Bipul; Soppet, William K.

This report provides an update of an earlier assessment of environmentally assisted fatigue for components in light water reactors. This report is a deliverable in September 2016 under the work package for environmentally assisted fatigue under DOE’s Light Water Reactor Sustainability program. In an April 2016 report, we presented a detailed thermal-mechanical stress analysis model for simulating the stress-strain state of a reactor pressure vessel and its nozzles under grid-load-following conditions. In this report, we provide stress-controlled fatigue test data for 508 LAS base metal alloy under different loading amplitudes (constant, variable, and random grid-load-following) and environmental conditions (in airmore » or pressurized water reactor coolant water at 300°C). Also presented is a cyclic plasticity-based analytical model that can simultaneously capture the amplitude and time dependency of the component behavior under fatigue loading. Results related to both amplitude-dependent and amplitude-independent parameters are presented. The validation results for the analytical/mechanistic model are discussed. This report provides guidance for estimating time-dependent, amplitude-independent parameters related to material behavior under different service conditions. The developed mechanistic models and the reported material parameters can be used to conduct more accurate fatigue and ratcheting evaluation of reactor components.« less

An Axial-Torsional, Thermomechanical Fatigue Testing Technique

NASA Technical Reports Server (NTRS)

Kalluri, Sreeramesh; Bonacuse, Peter J.

1995-01-01

A technique for conducting strain-controlled, thermomechanical, axial-torsional fatigue tests on thin-walled tubular specimens was developed. Three waveforms of loading, namely, the axial strain waveform, the engineering shear strain waveform, and the temperature waveform were required in these tests. The phasing relationships between the mechanical strain waveforms and the temperature and axial strain waveforms were used to define a set of four axial-torsional, thermomechanical fatigue (AT-TMF) tests. Real-time test control (3 channels) and data acquisition (a minimum of 7 channels) were performed with a software program written in C language and executed on a personal computer. The AT-TMF testing technique was used to investigate the axial-torsional thermomechanical fatigue behavior of a cobalt-base superalloy, Haynes 188. The maximum and minimum temperatures selected for the AT-TMF tests were 760 and 316 C, respectively. Details of the testing system, calibration of the dynamic temperature profile of the thin-walled tubular specimen, thermal strain compensation technique, and test control and data acquisition schemes, are reported. The isothermal, axial, torsional, and in- and out-of-phase axial-torsional fatigue behaviors of Haynes 188 at 316 and 760 C were characterized in previous investigations. The cyclic deformation and fatigue behaviors of Haynes 188 in AT-TMF tests are compared to the previously reported isothermal axial-torsional behavior of this superalloy at the maximum and minimum temperatures.

Mind-body medicine and lifestyle modification in supportive cancer care: A cohort study on a day care clinic program for cancer patients.

PubMed

Jeitler, Michael; Jaspers, Jessica; von Scheidt, Christel; Koch, Barbara; Michalsen, Andreas; Steckhan, Nico; Kessler, Christian S

2017-12-01

We developed an integrative day care clinic program for cancer patients focusing on mind-body techniques and health-promoting lifestyle modification (7-hour once-per-week group sessions over 12 weeks). A cohort study design with a waiting group was implemented. Outcome parameters were assessed at the beginning, at the end of the active program, and at a 6-month follow-up. Patients waiting >4 and <12 weeks before treatment start were allocated to the waiting group and additionally assessed at the start of their day care program. Outcome measures included quality of life (FACT-G, FACT-B/C, WHO-5), fatigue (FACIT-F), depression/anxiety (HADS), and mood states (ASTS). A per protocol analysis using mixed linear models was performed. One hundred patients were screened on-site for eligibility. Eighty-six cancer survivors (83% female; mean age 53.7 ± 9.7 years; 49% breast cancer) were included into the study. Sixty-two patients were allocated to the intervention group and 24 patients, to the waiting group (mean waiting time 5 ± 1 weeks). Sixty-six data sets were included in the final analysis. Significant improvements were observed in favor of the intervention group after 12 weeks compared with the waiting group at the end of the waiting period for quality of life, anxiety/depression, and fatigue. Results from the 6-month follow-up for the whole study population showed lasting improvement of quality of life. The program can be considered as an effective means to improve quality of life, fatigue, and mental health of cancer patients. Moreover, it appears to have a sustainable effect, which has to be proved in randomized trials. Copyright © 2017 John Wiley & Sons, Ltd.

Service and Methods Demonstrations Program Report

DOT National Transportation Integrated Search

1981-12-01

The Service and Methods Demonstrations (SMD) Program was established in 1974 to promote the development and widespread adoption of innovative transit services and transportation management techniques throughout the United States. The program focuses ...

Effects of a Short Physical Exercise Intervention on Patients with Multiple Sclerosis (MS).

PubMed

Kerling, Arno; Keweloh, Karin; Tegtbur, Uwe; Kück, Momme; Grams, Lena; Horstmann, Hauke; Windhagen, Anja

2015-07-10

The aim of this prospective randomized controlled trial was to investigate if a short-term endurance or combined endurance/resistance exercise program was sufficient to improve aerobic capacity and maximum force in adult patients (18-65 years) with multiple sclerosis (MS). All patients performed a three-month exercise program consisting of two training sessions per week, lasting 40 min each, with moderate intensity. All patients had a maximum value of 6 (low to moderate disability) on the Expanded Disability Status Scale (EDSS). One group (combined workout group (CWG); 15 females, 4 males) completed a combined endurance/resistance workout (20 min on a bicycle ergometer, followed by 20 min of resistance training), while the other group (endurance workout group (EWG); 13 females, 5 males) completed a 40 min endurance training program. Aerobic capacity was assessed as peak oxygen uptake, ventilatory anaerobic threshold, and workload expressed as Watts. Maximum force of knee and shoulder extensors and flexors was measured using isokinetic testing. Quality of life was assessed with the SF-36 questionnaire, and fatigue was measured using the Modified Fatigue Impact Scale. Both training groups increased in aerobic capacity and maximum force. EWG, as well as CWG, showed improvement in several subscales of the SF-36 questionnaire and decrease of their fatigue. A short exercise intervention increased both aerobic capacity and maximum force independent of whether endurance or combined endurance/resistance workouts were performed.

Advanced aircraft service life monitoring method via flight-by-flight load spectra

NASA Astrophysics Data System (ADS)

Lee, Hongchul

This research is an effort to understand current method and to propose an advanced method for Damage Tolerance Analysis (DTA) for the purpose of monitoring the aircraft service life. As one of tasks in the DTA, the current indirect Individual Aircraft Tracking (IAT) method for the F-16C/D Block 32 does not properly represent changes in flight usage severity affecting structural fatigue life. Therefore, an advanced aircraft service life monitoring method based on flight-by-flight load spectra is proposed and recommended for IAT program to track consumed fatigue life as an alternative to the current method which is based on the crack severity index (CSI) value. Damage Tolerance is one of aircraft design philosophies to ensure that aging aircrafts satisfy structural reliability in terms of fatigue failures throughout their service periods. IAT program, one of the most important tasks of DTA, is able to track potential structural crack growth at critical areas in the major airframe structural components of individual aircraft. The F-16C/D aircraft is equipped with a flight data recorder to monitor flight usage and provide the data to support structural load analysis. However, limited memory of flight data recorder allows user to monitor individual aircraft fatigue usage in terms of only the vertical inertia (NzW) data for calculating Crack Severity Index (CSI) value which defines the relative maneuver severity. Current IAT method for the F-16C/D Block 32 based on CSI value calculated from NzW is shown to be not accurate enough to monitor individual aircraft fatigue usage due to several problems. The proposed advanced aircraft service life monitoring method based on flight-by-flight load spectra is recommended as an improved method for the F-16C/D Block 32 aircraft. Flight-by-flight load spectra was generated from downloaded Crash Survival Flight Data Recorder (CSFDR) data by calculating loads for each time hack in selected flight data utilizing loads equations. From the comparison of interpolated fatigue life using CSI value and fatigue test results, it is obvious that proposed advanced IAT method via flight-by-flight load spectra is more reliable and accurate than current IAT method. Therefore, the advanced aircraft service life monitoring method based on flight-by-flight load spectra not only monitors the individual aircraft consumed fatigue life for inspection but also ensures the structural reliability of aging aircrafts throughout their service periods.

Fatigue damage characterization of braided and woven fiber reinforced polymer matrix composites at room and elevated temperatures

NASA Astrophysics Data System (ADS)

Montesano, John

The use of polymer matrix composites (PMC) for manufacturing primary load-bearing structural components has significantly increased in many industrial applications. Specifically in the aerospace industry, PMCs are also being considered for elevated temperature applications. Current aerospace-grade composite components subjected to fatigue loading are over-designed due to insufficient understanding of the material failure processes, and due to the lack of available generic fatigue prediction models. A comprehensive literature survey reveals that there are few fatigue studies conducted on woven and braided fabric reinforced PMC materials, and even fewer at elevated temperatures. It is therefore the objective of this study to characterize and subsequently model the elevated temperature fatigue behaviour of a triaxial braided PMC, and to investigate the elevated temperature fatigue properties of two additional woven PMCs. An extensive experimental program is conducted using a unique test protocol on the braided and woven composites, which consists of static and fatigue testing at various test temperatures. The development of mechanically-induced damage is monitored using a combination of non-destructive techniques which included infrared thermography, fiber optic sensors and edge replication. The observed microscopic damage development is quantified and correlated to the exhibited macroscopic material behaviour at all test temperatures. The fiber-dominated PMC materials considered in this study did not exhibit notable time- or temperature-dependent static properties. However, fatigue tests reveal that the local damage development is in fact notably influenced by temperature. The elevated temperature environment increases the toughness of the thermosetting polymers, which results in consistently slower fatigue crack propagation rates for the respective composite materials. This has a direct impact on the stiffness degradation rate and the fatigue lives for the braided and woven composites under investigation. The developed analytical fatigue damage prediction model, which is based on actual observed damage mechanisms, accurately predicted the development of damage and the corresponding stiffness degradation for the braided PMC, for all test temperatures. An excellent correlation was found between the experimental and the predicted results to within a 2% accuracy. The prediction model adequately captured the local temperature-induced phenomenon exhibited by the braided PMC material. The results presented in this study are novel for a braided composite material subjected to elevated temperature fatigue.

In-air and pressurized water reactor environment fatigue experiments of 316 stainless steel to study the effect of environment on cyclic hardening

NASA Astrophysics Data System (ADS)

Mohanty, Subhasish; Soppet, William K.; Majumdar, Saurindranath; Natesan, Krishnamurti

2016-05-01

Argonne National Laboratory (ANL), under the sponsorship of Department of Energy's Light Water Reactor Sustainability (LWRS) program, is trying to develop a mechanistic approach for more accurate life estimation of LWR components. In this context, ANL has conducted many fatigue experiments under different test and environment conditions on type 316 stainless steel (316 SS) material which is widely used in the US reactors. Contrary to the conventional S ∼ N curve based empirical fatigue life estimation approach, the aim of the present DOE sponsored work is to develop an understanding of the material ageing issues more mechanistically (e.g. time dependent hardening and softening) under different test and environmental conditions. Better mechanistic understanding will help develop computer-based advanced modeling tools to better extrapolate stress-strain evolution of reactor components under multi-axial stress states and hence help predict their fatigue life more accurately. Mechanics-based modeling of fatigue such as by using finite element (FE) tools requires the time/cycle dependent material hardening properties. Presently such time-dependent material hardening properties are hardly available in fatigue modeling literature even under in-air conditions. Getting those material properties under PWR environment, are even harder. Through this work we made preliminary attempt to generate time/cycle dependent stress-strain data both under in-air and PWR water conditions for further study such as for possible development of material models and constitutive relations for FE model implementation. Although, there are open-ended possibility to further improve the discussed test methods and related material estimation techniques we anticipate that the data presented in this paper will help the metal fatigue research community particularly, the researchers who are dealing with mechanistic modeling of metal fatigue such as using FE tools. In this paper the fatigue experiments under different test and environment conditions and related stress-strain results for 316 SS are discussed.

A root-mean-square approach for predicting fatigue crack growth under random loading

NASA Technical Reports Server (NTRS)

Hudson, C. M.

1981-01-01

A method for predicting fatigue crack growth under random loading which employs the concept of Barsom (1976) is presented. In accordance with this method, the loading history for each specimen is analyzed to determine the root-mean-square maximum and minimum stresses, and the predictions are made by assuming the tests have been conducted under constant-amplitude loading at the root-mean-square maximum and minimum levels. The procedure requires a simple computer program and a desk-top computer. For the eleven predictions made, the ratios of the predicted lives to the test lives ranged from 2.13 to 0.82, which is a good result, considering that the normal scatter in the fatigue-crack-growth rates may range from a factor of two to four under identical loading conditions.

Benefits of Pulmonary Rehabilitation in Idiopathic Pulmonary Fibrosis

PubMed Central

Swigris, Jeffrey J.; Fairclough, Diane L.; Morrison, Marianne; Make, Barry; Kozora, Elizabeth; Brown, Kevin K.; Wamboldt, Frederick S.

2013-01-01

BACKGROUND Information on the benefits of pulmonary rehabilitation (PR) in patients with idiopathic pulmonary fibrosis (IPF) is growing, but PR’s effects on certain important outcomes is lacking. METHODS We conducted a pilot study of PR in IPF and analyzed changes in functional capacity, fatigue, anxiety, depression, sleep, and health status from baseline to after completion of a standard, 6-week PR program. RESULTS Six-min walk distance improved a mean ± standard error 202 ± 135 feet (P = .01) from baseline. Fatigue Severity Scale score also improved significantly, declining an average 1.5 ± 0.5 points from baseline. There were trends toward improvement in anxiety, depression, and health status. CONCLUSIONS PR improves functional capacity and fatigue in patients with IPF. (ClinicalTrials.gov registration NCT00692796.) PMID:21333082

Prediction of thermal cycling induced matrix cracking

NASA Technical Reports Server (NTRS)

Mcmanus, Hugh L.

1992-01-01

Thermal fatigue has been observed to cause matrix cracking in laminated composite materials. A method is presented to predict transverse matrix cracks in composite laminates subjected to cyclic thermal load. Shear lag stress approximations and a simple energy-based fracture criteria are used to predict crack densities as a function of temperature. Prediction of crack densities as a function of thermal cycling is accomplished by assuming that fatigue degrades the material's inherent resistance to cracking. The method is implemented as a computer program. A simple experiment provides data on progressive cracking of a laminate with decreasing temperature. Existing data on thermal fatigue is also used. Correlations of the analytical predictions to the data are very good. A parametric study using the analytical method is presented which provides insight into material behavior under cyclical thermal loads.

Diagnostic Reasoning for ST-Segment Elevation Myocardial Infarction (STEMI) Interpretation Is Preserved Despite Fatigue

PubMed Central

Kellogg, Adam R.; Coute, Ryan A.; Garra, Gregory

2015-01-01

Background Fatigue and sleepiness contribute to medical errors, although the effect of circadian disruption and fatigue on diagnostic reasoning skills is largely unknown. Objective To determine whether circadian disruption and fatigue negatively affect the emergency medicine (EM) resident's ability to make important clinical decisions based on electrocardiogram (ECG) interpretation. Methods Senior EM residents at 2 programs completed a questionnaire consisting of various measures of fatigue followed by an ECG test packet of ST-segment elevation myocardial infarction (STEMI) and STEMI mimics. Participants were asked to examine each ECG and determine whether cardiac catheterization laboratory activation (CLA) was indicated, and to report their confidence in their decision making on an 11-point, numeric rating scale. The primary outcome measured was a pairwise difference in accuracy of CLA between daytime and overnight testing. Results A total of 23 residents were enrolled in 2011 and 2012. Subjects demonstrated significant differences in multiple measures of sleepiness and fatigue during overnight periods. The median (interquartile range [IQR]) accuracy of CLA was not significantly different between daytime and overnight (70% [IQR, 50–80] versus 70% [IQR, 60–70], P  =  .82). There were no significant differences in the median number of overcalls (CLA when not a STEMI) and undercalls (no CLA when a STEMI was present; P  =  .57 and .37, respectively). Diagnostic confidence and confidence in CLA were not statistically different between daytime and overnight. Conclusions Despite a measurable degree of fatigue, senior EM residents experienced no decrease in their ability to accurately make CLA decisions based on ECG interpretation. PMID:26217418

Diagnostic Reasoning for ST-Segment Elevation Myocardial Infarction (STEMI) Interpretation Is Preserved Despite Fatigue.

PubMed

Kellogg, Adam R; Coute, Ryan A; Garra, Gregory

2015-03-01

Fatigue and sleepiness contribute to medical errors, although the effect of circadian disruption and fatigue on diagnostic reasoning skills is largely unknown. To determine whether circadian disruption and fatigue negatively affect the emergency medicine (EM) resident's ability to make important clinical decisions based on electrocardiogram (ECG) interpretation. Senior EM residents at 2 programs completed a questionnaire consisting of various measures of fatigue followed by an ECG test packet of ST-segment elevation myocardial infarction (STEMI) and STEMI mimics. Participants were asked to examine each ECG and determine whether cardiac catheterization laboratory activation (CLA) was indicated, and to report their confidence in their decision making on an 11-point, numeric rating scale. The primary outcome measured was a pairwise difference in accuracy of CLA between daytime and overnight testing. A total of 23 residents were enrolled in 2011 and 2012. Subjects demonstrated significant differences in multiple measures of sleepiness and fatigue during overnight periods. The median (interquartile range [IQR]) accuracy of CLA was not significantly different between daytime and overnight (70% [IQR, 50-80] versus 70% [IQR, 60-70], P  =  .82). There were no significant differences in the median number of overcalls (CLA when not a STEMI) and undercalls (no CLA when a STEMI was present; P  =  .57 and .37, respectively). Diagnostic confidence and confidence in CLA were not statistically different between daytime and overnight. Despite a measurable degree of fatigue, senior EM residents experienced no decrease in their ability to accurately make CLA decisions based on ECG interpretation.

The Effects of Shot and Laser Peening on Fatigue Life and Crack Growth in 2024 Aluminum Alloy and 4340 Steel

NASA Technical Reports Server (NTRS)

Everett, R. A., Jr.; Matthews, W. T.; Prabhakaran, R.; Newman, J. C., Jr.; Dubberly, M. J.

2001-01-01

Fatigue and crack growth tests have been conducted on 4340 steel and 2024-T3 aluminum alloy, respectively, to assess the effects of shot peening on fatigue life and the effects of shot and laser peening on crack growth. Two current programs involving fixed and rotary-wing aircraft will not be using shot peened structures. Since the shot peening compressive residual stress depth is usually less than the 0.05-inch initial damage tolerance crack size, it is believed by some that shot peening should have no beneficial effects toward retarding crack growth. In this study cracks were initiated from an electronic-discharged machining flaw which was cycled to produce a fatigue crack of approximately 0.05-inches in length and then the specimens were peened. Test results showed that after peening the crack growth rates were noticeably slower when the cracks were fairly short for both the shot and laser peened specimens resulting in a crack growth life that was a factor of 2 to 4 times greater than the results of the average unpeened test. Once the cracks reached a length of approximately 0.1-inches the growth rates were about the same for the peened and unpeened specimens. Fatigue tests on 4340 steel showed that the endurance limit of a test specimen with a 0.002-inch-deep machining-like scratch was reduced by approximately 40 percent. However, if the "scratched" specimen was shot peened after inserting the scratch, the fatigue life returned to almost 100 percent of the unflawed specimens original fatigue life.

The effect of relaxation therapy on autonomic functioning, symptoms and daily functioning, in patients with chronic fatigue syndrome or fibromyalgia: a systematic review.

PubMed

Meeus, Mira; Nijs, Jo; Vanderheiden, Tanja; Baert, Isabel; Descheemaeker, Filip; Struyf, Filip

2015-03-01

To establish the effects of relaxation therapy on autonomic function, pain, fatigue and daily functioning in patients with chronic fatigue syndrome or fibromyalgia. A systematic literature study was performed. Using specific keywords related to fibromyalgia or chronic fatigue syndrome and relaxation therapy, the electronic databases PubMed and Web of Science were searched. Included articles were assessed for their risk of bias and relevant information regarding relaxation was extracted. The review was conducted and reported according to the PRISMA-statement. Thirteen randomized clinical trials of sufficient quality were included, resulting in a total of 650 fibromyalgia patients (11 studies) and 88 chronic fatigue syndrome patients (3 studies). None of the studies reported effects on autonomic function. Six studies reported the effect of guided imagery on pain and daily functioning in fibromyalgia. The acute effect of a single session of guided imagery was studied in two studies and seems beneficial for pain relief. For other relaxation techniques (eg. muscle relaxation, autogenic training) no conclusive evidence was found for the effect on pain and functioning in fibromyalgia patients comparison to multimodal treatment programs. For fatigue a multimodal approach seemed better than relaxation, as shown in the sole three studies on chronic fatigue syndrome patients. There is moderate evidence for the acute effect of guided imagery on pain, although the content of the visualization is a matter of debate. Other relaxation formats and the effects on functionality and autonomic function require further study. © The Author(s) 2014.

Tensile and Fatigue Testing and Material Hardening Model Development for 508 LAS Base Metal and 316 SS Similar Metal Weld under In-air and PWR Primary Loop Water Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohanty, Subhasish; Soppet, William; Majumdar, Saurin

This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable in September 2015 under the work package for environmentally assisted fatigue under DOE’s Light Water Reactor Sustainability program. In an April 2015 report we presented a baseline mechanistic finite element model of a two-loop pressurized water reactor (PWR) for systemlevel heat transfer analysis and subsequent thermal-mechanical stress analysis and fatigue life estimation under reactor thermal-mechanical cycles. In the present report, we provide tensile and fatigue test data for 508 low-alloy steel (LAS) base metal,more » 508 LAS heat-affected zone metal in 508 LAS–316 stainless steel (SS) dissimilar metal welds, and 316 SS-316 SS similar metal welds. The test was conducted under different conditions such as in air at room temperature, in air at 300 oC, and under PWR primary loop water conditions. Data are provided on materials properties related to time-independent tensile tests and time-dependent cyclic tests, such as elastic modulus, elastic and offset strain yield limit stress, and linear and nonlinear kinematic hardening model parameters. The overall objective of this report is to provide guidance to estimate tensile/fatigue hardening parameters from test data. Also, the material models and parameters reported here can directly be used in commercially available finite element codes for fatigue and ratcheting evaluation of reactor components under in-air and PWR water conditions.« less

Non-linear dynamics in muscle fatigue and strength model during maximal self-perceived elbow extensors training.

PubMed

Gacesa, Jelena Popadic; Ivancevic, Tijana; Ivancevic, Nik; Paljic, Feodora Popic; Grujic, Nikola

2010-08-26

Our aim was to determine the dynamics in muscle strength increase and fatigue development during repetitive maximal contraction in specific maximal self-perceived elbow extensors training program. We will derive our functional model for m. triceps brachii in spirit of traditional Hill's two-component muscular model and after fitting our data, develop a prediction tool for this specific training system. Thirty-six healthy young men (21 +/- 1.0 y, BMI 25.4 +/- 7.2 kg/m(2)), who did not take part in any formal resistance exercise regime, volunteered for this study. The training protocol was performed on the isoacceleration dynamometer, lasted for 12 weeks, with a frequency of five sessions per week. Each training session included five sets of 10 maximal contractions (elbow extensions) with a 1 min resting period between each set. The non-linear dynamic system model was used for fitting our data in conjunction with the Levenberg-Marquardt regression algorithm. As a proper dynamical system, our functional model of m. triceps brachii can be used for prediction and control. The model can be used for the predictions of muscular fatigue in a single series, the cumulative daily muscular fatigue and the muscular growth throughout the training process. In conclusion, the application of non-linear dynamics in this particular training model allows us to mathematically explain some functional changes in the skeletal muscle as a result of its adaptation to programmed physical activity-training. 2010 Elsevier Ltd. All rights reserved.

Ageing airplane repair assessment program for Airbus A300

NASA Technical Reports Server (NTRS)

Gaillardon, J. M.; Schmidt, HANS-J.; Brandecker, B.

1992-01-01

This paper describes the current status of the repair categorization activities and includes all details about the methodologies developed for determination of the inspection program for the skin on pressurized fuselages. For inspection threshold determination two methods are defined based on fatigue life approach, a simplified and detailed method. The detailed method considers 15 different parameters to assess the influences of material, geometry, size location, aircraft usage, and workmanship on the fatigue life of the repair and the original structure. For definition of the inspection intervals a general method is developed which applies to all concerned repairs. For this the initial flaw concept is used by considering 6 parameters and the detectable flaw sizes depending on proposed nondestructive inspection methods. An alternative method is provided for small repairs allowing visual inspection with shorter intervals.

United States Air Force Graduate Student Research Program for 1990. Program Management Report

DTIC Science & Technology

1992-06-05

were extensively studied using pencil lead breaks in a center notch. For the fatigue studies center crack samples of 2024 - T351 aluminum were used...Research Program (SFRP) provides opportunities for research in the physical sciences, engineering, and life sciences. The program has been effective ...positive effect on teaching. (WRDC/FDL) Several mentioned the opportunity for introduction to research interests of the Air Force and the opportunity to work

Excessive peptidergic sensory innervation of cutaneous arteriole-venule shunts (AVS) in the palmar glabrous skin of fibromyalgia patients: implications for widespread deep tissue pain and fatigue.

PubMed

Albrecht, Phillip J; Hou, Quanzhi; Argoff, Charles E; Storey, James R; Wymer, James P; Rice, Frank L

2013-06-01

To determine if peripheral neuropathology exists among the innervation of cutaneous arterioles and arteriole-venule shunts (AVS) in fibromyalgia (FM) patients. Cutaneous arterioles and AVS receive a convergence of vasoconstrictive sympathetic innervation, and vasodilatory small-fiber sensory innervation. Given our previous findings of peripheral pathologies in chronic pain conditions, we hypothesized that this vascular location may be a potential site of pathology and/or serotonergic and norepinephrine reuptake inhibitors (SNRI) drug action. Twenty-four female FM patients and nine female healthy control subjects were enrolled for study, with 14 additional female control subjects included from previous studies. AVS were identified in hypothenar skin biopsies from 18/24 FM patient and 14/23 control subjects. Multimolecular immunocytochemistry to assess different types of cutaneous innervation in 3 mm skin biopsies from glabrous hypothenar and trapezius regions. AVS had significantly increased innervation among FM patients. The excessive innervation consisted of a greater proportion of vasodilatory sensory fibers, compared with vasoconstrictive sympathetic fibers. In contrast, sensory and sympathetic innervation to arterioles remained normal. Importantly, the sensory fibers express α2C receptors, indicating that the sympathetic innervation exerts an inhibitory modulation of sensory activity. The excessive sensory innervation to the glabrous skin AVS is a likely source of severe pain and tenderness in the hands of FM patients. Importantly, glabrous AVS regulate blood flow to the skin in humans for thermoregulation and to other tissues such as skeletal muscle during periods of increased metabolic demand. Therefore, blood flow dysregulation as a result of excessive innervation to AVS would likely contribute to the widespread deep pain and fatigue of FM. SNRI compounds may provide partial therapeutic benefit by enhancing the impact of sympathetically mediated inhibitory modulation of the excess sensory innervation. Wiley Periodicals, Inc.

Physical activity and training in sarcoidosis: review and experience-based recommendations.

PubMed

Strookappe, Bert; Saketkoo, Lesley Ann; Elfferich, Marjon; Holland, Anne; De Vries, Jolanda; Knevel, Ton; Drent, Marjolein

2016-10-01

Sarcoidosis is a multisystemic inflammatory disorder with a great variety of symptoms, including fatigue, dyspnea, pain, reduced exercise tolerance and muscle strength. Physical training has the potential to improve exercise capacity and muscle strength, and reduce fatigue. The aim of this review and survey was to present information about the role of physical training in sarcoidosis and offer practical guidelines. A systematic literature review guided an international consensus effort among sarcoidosis experts to establish practice-basic recommendations for the implementation of exercise as treatment for patients with various manifestations of sarcoidosis. International sarcoidosis experts suggested considering physical training in symptomatic patients with sarcoidosis. Expert commentary: There is promising evidence of a positive effect of physical training. Recommendations were based on available data and expert consensus. However, the heterogeneity of these patients will require modification and program adjustment of the standard rehabilitation format for e.g. COPD or interstitial lung diseases. An optimal training program (types of exercise, intensities, frequency, duration) still needs to be defined to optimize training adjustments, especially reduction of fatigue. Further randomized controlled trials are needed to consolidate these findings and optimize the comprehensive care of sarcoidosis patients.

Creep fatigue life prediction for engine hot section materials (isotropic)

NASA Technical Reports Server (NTRS)

Nelson, R. S.; Levan, G. W.; Harvey, P. R.

1992-01-01

This Final Report covers the activities completed under the optional program of the NASA HOST Contract, NAS3-23288. The initial effort of the optional program was report-in NASA CR189221, which consisted of high temperature strain controlled fatigue tests to study the effects of thermomechanical fatigue, multiaxial loading, reactive environments, and imposed stresses. The baseline alloy used in the tests included B1900+Hf (with or without coating) and wrought INCO 718. Tests conducted on B1900+Hf included environmental tests using various atmospheres (75 psig oxygen, purified argon, or block exposures) and specimen tests of wrought INCO 718 included tensile, creep, stress rupture, TMF, multiaxial, and mean stress tests. Results of these testings were used to calibrate a CDA model for INCO 718 alloy and to develop modifications or corrections to the CDA model to handle additional failure mechanisms. The Socie parameter was found to provide the best correlation for INCO multiaxial loading. Microstructural evaluations consisting of optical, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) techniques, and surface replication techniques to determine crack initiation lives provided data which were used to develop life prediction models.

Creep fatigue life prediction for engine hot section materials (isotropic)

NASA Technical Reports Server (NTRS)

Moreno, V.

1983-01-01

The Hot Section Technology (HOST) program, creep fatigue life prediction for engine hot section materials (isotropic), is reviewed. The program is aimed at improving the high temperature crack initiation life prediction technology for gas turbine hot section components. Significant results include: (1) cast B1900 and wrought IN 718 selected as the base and alternative materials respectively; (2) fatigue test specimens indicated that measurable surface cracks appear early in the specimen lives, i.e., 15% of total life at 871 C and 50% of life at 538 c; (3) observed crack initiation sites are all surface initiated and are associated with either grain boundary carbides or local porosity, transgrannular cracking is observed at the initiation site for all conditions tested; and (4) an initial evaluation of two life prediction models, representative of macroscopic (Coffin-Mason) and more microscopic (damage rate) approaches, was conducted using limited data generated at 871 C and 538 C. It is found that the microscopic approach provides a more accurate regression of the data used to determine crack initiation model constants, but overpredicts the effect of strain rate on crack initiation life for the conditions tested.

USAF Damage Tolerant Design Handbook: Guidelines for the analysis and Design of Damage Tolerant Aircraft Structures. Revision A

DTIC Science & Technology

1979-03-01

Fatigue Crack Growth (Schr~matic) 5.12 Sustained Load Crack Growth Rate Data for 7075-f651,7079- T651, and 2024 - T351 Aluminum Plate (Ref...Block Programming and Block Size on Crack Growth Life (All histories Have Same Cycle Content) Alloy : 2024 -T3 Aluminum (Ref. 38) 5.21 Yield Zone Due to...4340 Steel in Humid Air," ASM Trans 58, 46-53 (1965). 20. Meyn, D.A., "Frequency and Amplitude Effects on Corrosion Fatigue Cracks in a Titanium Alloy

Hand hygiene promotion and the participation of infection control link nurses: an effective innovation to overcome campaign fatigue.

PubMed

Seto, Wing Hong; Yuen, Shanny W S; Cheung, Christina W Y; Ching, Patricia T Y; Cowling, Benjamin J; Pittet, Didier

2013-12-01

Campaign fatigue was evident in a large hospital in Hong Kong when hand hygiene compliance remained just above 50% after 4 years of aggressive and varied promotional activities. A new innovative strategy was developed that directly involved the infection control link nurses both in formulating the strategy and in implementing the various proposed programs. The new strategy was successful in increasing hand hygiene compliance to 83%. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Microstructural Influences on Very High Cycle Fatigue Crack Initiation in Ti-6246 (PREPRINT)

DTIC Science & Technology

2008-04-01

surface (in degrees). Facet # 1 2 3 4 5a 5b 6 7 8 9 Angle 46 45 39 19 26 35 33 31 32 21 Table II. Orientation of facets (in degrees). Facet # 1* 2 3 4 ...TYPE 3. DATES COVERED (From - To) April 2008 Journal Article Preprint 4 . TITLE AND SUBTITLE MICROSTRUCTURAL INFLUENCES ON VERY HIGH CYCLE...FATIGUE CRACK INITIATION IN Ti-6246 (PREPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6 . AUTHOR(S

The Mean vs Life-Limiting Fatigue Response of a Ni-Base Superalloy, Part 1: Mechanisms (Preprint)

DTIC Science & Technology

2008-09-01

34’"L’\\" ~~·~~~:~~~?~i.. ~ ~I~~~.~.’ ,~.- .":_~ ••-:;’~.:-- 10JJITl 3 4 S 6 Grain diameter (",m) Figure 1: Microstructure of the INIOO...DATES COVERED (From - To) September 2008 Journal Article Preprint 4 . TITLE AND SUBTITLE THE MEAN VS LIFE-LIMITING FATIGUE RESPONSE OF A Ni-BASE...SUPERALLOY, PART 1: MECHANISMS (PREPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6 . AUTHOR(S

Residual Stress, Micro- and Macrotexture in Surface-Enhanced Titanium Alloys: Their Nondestructive Inspection and Effects on High-Cycle Fatigue Properties

DTIC Science & Technology

2006-05-01

Titanium 5b. GRANT NUMBER Alloys: Their Nondestructive Inspection and Effects on High-Cycle Fatigue Properties 5c. PROGRAM ELEMENT NUMBER 6 . AUTHOR(S) 5d...was relatively inaccurate in our measurements Table 1. Parameters of Eqs. ( 4 ) and (5) fitted to the experimental results of Fig. 6 . The statistical...jgm below the surface. Depth (X 10𔃽mm) 0 50 100 IS0 200 250 300 -25. 0. -2 .... .. ....... oo ... ........... 2,.0 . ... o -1000 -- 80 0 2 4 6 8 10 12

Fatigue Behavior of Long and Short Cracks in Wrought and Powder Aluminum Alloys.

DTIC Science & Technology

1984-05-01

PROGRAM ELEMENT. PROJECT. TASK AREA & WORK UNIT NUMBERS Robert 0. Ritchie, Department of Materials Science and Mineral Engineering, University of 2306/ Al ...Chemical Compositions in wt% of Alloys Si Fe Cu Mn Mg Cr Zn Ti Zr Al 2024 0.50 0.50 4.50 0.50 1.50 0.10 0.25 0.15 -- balance 2124 0.20 0.30 4.50 0.50 1.50...been applied by Suresh et al .41 to rationalize the microstructural effects of precipitation hardening on fatigue crack growth in 7075 alloys. The

The Purpose of Generating Fatigue Crack Growth Threshold Data

NASA Technical Reports Server (NTRS)

Forth, Scott

2006-01-01

Test data shows that different width and thickness C(T), M(T) and ESE(T) specimens generate different thresholds Structures designed for "infinite life" are being re-evaluated: a) Threshold changes from 6 to 3 ksi in(sup 1/2); b) Computational life changes from infinite to 4 missions. Multi-million dollar test programs required to substantiate operation. Using ASTM E647 as standard guidance to generate threshold data is not practical. A threshold test approach needs to be standardized that will provide positive margin for high cycle fatigue applications.

Sustainable impact of an individualized exercise program on physical activity level and fatigue syndrome on breast cancer patients in two German rehabilitation centers.

PubMed

Baumann, Freerk T; Bieck, Oliver; Oberste, Max; Kuhn, Rafaela; Schmitt, Joachim; Wentrock, Steffen; Zopf, Eva; Bloch, Wilhelm; Schüle, Klaus; Reuss-Borst, Monika

2017-04-01

Although physical activity has been demonstrated to increase cancer survival in epidemiological studies, breast cancer patients tend toward inactivity after treatment. Breast cancer patients were quasi-randomly allocated to two different groups, intervention (IG) and control (CG) groups. The intervention group (n = 111) received an individual 3-week exercise program with two additional 1-week inpatient stays after 4 and 8 months. At the end of the rehabilitation, a home-based exercise program was designed. The control group (n = 83) received a 3-week rehabilitation program and did not obtain any follow-up care. Patients from both groups were measured using questionnaires on physical activity, fatigue, and quality of life (QoL) at five time points, 4 months (t1), 8 months (t2), 12 months (t3), 18 months (t4), and 24 months (t5) after the beginning of the rehabilitation. After 2 years, the level of physical activity (total metabolic rate) increased significantly from 2733.16 ± 2547.95 (t0) to 4169.71 ± 3492.27 (t5) metabolic equivalent (MET)-min/week in the intervention group, but just slightly changed from 2858.38 ± 2393.79 (t0) to 2875.74 ± 2590.15 (t5) MET-min/week in the control group (means ± standard deviation). Furthermore, the internal group comparison showed significant differences after 2 years as well. These results came along with a significantly reduced fatigue syndrome and an increased health-related quality of life. The data indicate that an individual, according to their preferences, and physical-resource-adapted exercise program has a more sustainable impact on the physical activity level in breast cancer patients than the usual care. It is suggested that the rehabilitation program should be personalized for all breast cancer patients.

[The effects of foot reflexology on nausea, vomiting and fatigue of breast cancer patients undergoing chemotherapy].

PubMed

Yang, Jin-Hyang

2005-02-01

The purpose of this study was to identify the effects of foot reflexology on nausea, vomiting and fatigue in breast cancer patients undergoing chemotherapy. The research was a quasi-experimental study using a non-equivalent pre-post design and was conducted from Jan. 26, to Mar. 20, 2004. The subjects consisted of 34 patients with 18 in the experimental group and 16 in control group. A pretest and 2 posttests were conducted to measure nausea, vomiting and fatigue. For the experimental group, foot reflexology, which was consisted of 4 phases for 40 minutes, was given by a researcher and 4 research assistants. The collected data were analyzed by repeated measures ANOVA using the SPSS WIN 10.0 program. There was a statistically significant decrease in nausea, and vomiting in the experimental group compared to the control group over two different times. In addition, there was a statistically significant decrease in fatigue in the experimental group compared to the control group over two different times. Foot reflexology was effective on nausea, vomiting and fatigue in breast cancer patients receiving chemotherapy in this study. Therefore, foot reflexology can be usefully utilized as a nursing intervention in the field of cancer nursing for breast cancer patients receiving chemotherapy.

Muscle fatigue during intermittent exercise in individuals with mental retardation.

PubMed

Zafeiridis, Andreas; Giagazoglou, Paraskevi; Dipla, Konstantina; Salonikidis, Konstantinos; Karra, Chrisanthi; Kellis, Eleftherios

2010-01-01

This study examined fatigue profile during intermittent exercise in 10 men with mild to moderate mental retardation (MR) and 10 men without mental retardation (C). They performed 4 x 30s maximal knee extensions and flexions with 1-min rest on an isokinetic dynamometer. Peak torque of flexors (PTFL) and extensors (PTEX), total work (TW), and lactate were measured. Fatigue was calculated as the magnitude of decline (%) in PTFL, PTEX, and TW and as rate of decline (linear slope) in TW from 1st to 4th set. MR had lower PTFL, PTEX, TW, and lactate throughout the protocol than C, while pre-motor time was greater in MR vs. C (p<0.05). MR demonstrated a delayed pattern of reduction in muscular performance. Lower values were observed in MR vs. C in the magnitude of decline for PTEX and TW and the rate of decline for TW. In conclusion, MR exhibit a different fatigue profile during intermittent exercise than C. The lower magnitude and decline rate in neuromuscular performance in MR during intermittent exercise is associated with their lower peak strength, short-term anaerobic capacity, and lactate accumulation. Rehabilitation and sport professionals should consider the differences in fatigue profile when designing intermittent exercise programs for MR. Copyright 2009 Elsevier Ltd. All rights reserved.

Reliable high-power diode lasers: thermo-mechanical fatigue aspects

NASA Astrophysics Data System (ADS)

Klumel, Genady; Gridish, Yaakov; Szafranek, Igor; Karni, Yoram

2006-02-01

High power water-cooled diode lasers are finding increasing demand in biomedical, cosmetic and industrial applications, where repetitive cw (continuous wave) and pulsed cw operation modes are required. When operating in such modes, the lasers experience numerous complete thermal cycles between "cold" heat sink temperature and the "hot" temperature typical of thermally equilibrated cw operation. It is clearly demonstrated that the main failure mechanism directly linked to repetitive cw operation is thermo-mechanical fatigue of the solder joints adjacent to the laser bars, especially when "soft" solders are used. Analyses of the bonding interfaces were carried out using scanning electron microscopy. It was observed that intermetallic compounds, formed already during the bonding process, lead to the solders fatigue both on the p- and n-side of the laser bar. Fatigue failure of solder joints in repetitive cw operation reduces useful lifetime of the stacks to hundreds hours, in comparison with more than 10,000 hours lifetime typically demonstrated in commonly adopted non-stop cw reliability testing programs. It is shown, that proper selection of package materials and solders, careful design of fatigue sensitive parts and burn-in screening in the hard pulse operation mode allow considerable increase of lifetime and reliability, without compromising the device efficiency, optical power density and compactness.

Fatigue crack growth behaviour of semi-elliptical surface cracks for an API 5L X65 gas pipeline under tension

NASA Astrophysics Data System (ADS)

Shaari, M. S.; Akramin, M. R. M.; Ariffin, A. K.; Abdullah, S.; Kikuchi, M.

2018-02-01

The paper is presenting the fatigue crack growth (FCG) behavior of semi-elliptical surface cracks for API X65 gas pipeline using S-version FEM. A method known as global-local overlay technique was used in this study to predict the fatigue behavior that involve of two separate meshes each specifically for global (geometry) and local (crack). The pre-post program was used to model the global geometry (coarser mesh) known as FAST including the material and boundary conditions. Hence, the local crack (finer mesh) will be defined the exact location and the mesh control accordingly. The local mesh was overlaid along with the global before the numerical computation taken place to solve the engineering problem. The stress intensity factors were computed using the virtual crack closure-integral method (VCCM). The most important results is the behavior of the fatigue crack growth, which contains the crack depth (a), crack length (c) and stress intensity factors (SIF). The correlation between the fatigue crack growth and the SIF shows a good growth for the crack depth (a) and dissimilar for the crack length (c) where stunned behavior was resulted. The S-version FEM will benefiting the user due to the overlay technique where it will shorten the computation process.

Roles of interfacial reaction on mechanical properties of solder interfaces

NASA Astrophysics Data System (ADS)

Liu, Pilin

This study investigated roles of interfacial reaction in fracture and fatigue of solder interconnects. The interfacial reaction phases in the as-reflowed and after aging were examined by cross-sectional transmission electron microscopy (TEM) while interfacial mechanical properties were determined from a flexural peel fracture mechanics technique. Because of their widespread uses in microelectronic packaging, SnPb solder interfaces, and Bi-containing Pb-free solder interfaces were chosen as the subjects of this study. In the interfacial reaction study, we observed a complicated micro structural evolution during solid-state aging of electroless-Ni(P)/SnPb solder interconnects. In as-reflowed condition, the interfacial reaction produced Ni3Sn 4 and P-rich layers. Following overaging, the interfacial microstructure degenerated into a complex multilayer structure consisting of multiple layers of Ni-Sn compounds and transformed Ni-P phases. In SnPb solder interfacial system, fatigue study showed that the overaging of the high P electroless Ni-P/SnPb interconnects resulted in a sharp reduction in the fatigue resistance of the interface in the high crack growth rate regime. Fracture mechanism analysis indicated that the sharp drop in fatigue resistance was triggered by the brittle fracture of the Ni3Sn2 intermetallic phase developed at the overaged interface. The fatigue behavior was strongly dependent on P concentration in electroless Ni. Kirkendall voids were found in the interfacial region after aging, but they did not cause premature fracture of the solder interfaces. In Bi-containing solder interfacial system, we found that Bi segregated to the Cu-intermetallic interface during aging in SnBi/Cu interconnect. This caused serious embrittlement of Sn-Bi/Cu interface. Further aging induced numerous voids along the Cu3Sn/Cu interface. These interfacial voids were different from Kirkendall voids. Their formation was explained on basis of vacancy condensation at the interface as the Bi segregants reduced the number of effective Cu vacancy sink sites and enhanced void nucleation at the interface. The Bi segregation was avoided by replacing the Cu metallization with Ni. It was found that Bi developed a concentration gradient in the Ni 3Sn4 during interfacial reaction, with the Bi concentration falling off to zero as the Ni/IMC interface was approached. Therefore, the inhibition of Bi segregation by Ni was due to the inability of Bi to reach Ni/IMC interface.

Muscular Activity and Fatigue in Lower-Limb and Trunk Muscles during Different Sit-To-Stand Tests.

PubMed

Roldán-Jiménez, Cristina; Bennett, Paul; Cuesta-Vargas, Antonio I

2015-01-01

Sit-to-stand (STS) tests measure the ability to get up from a chair, reproducing an important component of daily living activity. As this functional task is essential for human independence, STS performance has been studied in the past decades using several methods, including electromyography. The aim of this study was to measure muscular activity and fatigue during different repetitions and speeds of STS tasks using surface electromyography in lower-limb and trunk muscles. This cross-sectional study recruited 30 healthy young adults. Average muscle activation, percentage of maximum voluntary contraction, muscle involvement in motion and fatigue were measured using surface electrodes placed on the medial gastrocnemius (MG), biceps femoris (BF), vastus medialis of the quadriceps (QM), the abdominal rectus (AR), erector spinae (ES), rectus femoris (RF), soleus (SO) and the tibialis anterior (TA). Five-repetition STS, 10-repetition STS and 30-second STS variants were performed. MG, BF, QM, ES and RF muscles showed differences in muscle activation, while QM, AR and ES muscles showed significant differences in MVC percentage. Also, significant differences in fatigue were found in QM muscle between different STS tests. There was no statistically significant fatigue in the BF, MG and SO muscles of the leg although there appeared to be a trend of increasing fatigue. These results could be useful in describing the functional movements of the STS test used in rehabilitation programs, notwithstanding that they were measured in healthy young subjects.

NASALife-Component Fatigue and Creep Life Prediction Program and Illustrative Examples

NASA Technical Reports Server (NTRS)

Murthy, Pappu L. N.; Mital, Subodh K.; Gyekenyesi, John Z.

2005-01-01

NASALife is a life prediction program for propulsion system components made of ceramic matrix composites (CMC) under cyclic thermo-mechanical loading and creep rupture conditions. Although, the primary focus was for CMC components the underlying methodologies are equally applicable to other material systems as well. The program references data for low cycle fatigue (LCF), creep rupture, and static material properties as part of the life prediction process. Multiaxial stresses are accommodated by Von Mises based methods and a Walker model is used to address mean stress effects. Varying loads are reduced by the Rainflow counting method. Lastly, damage due to cyclic loading (Miner s rule) and creep are combined to determine the total damage per mission and the number of missions the component can survive before failure are calculated. Illustration of code usage is provided through example problem of a CMC turbine stator vane made of melt-infiltrated, silicon carbide fiber-reinforced, silicon carbide matrix composite (MI SiC/SiC)

Recent advances in active noise and vibration control at NASA Langley Research Center

NASA Astrophysics Data System (ADS)

Gibbs, Gary P.; Cabell, Randolph H.; Palumbo, Daniel L.; Silcox, Richard J.; Turner, Travis L.

2002-11-01

Over the past 15 years NASA has investigated the use of active control technology for aircraft interior noise. More recently this work has been supported through the Advanced Subsonic Technology Noise Reduction Program (1994-2001), High Speed Research Program (1994-1999), and through the Quiet Aircraft Technology Program (2000-present). The interior environment is recognized as an important element in flight safety, crew communications and fatigue, as well as passenger comfort. This presentation will overview research in active noise and vibration control relating to interior noise being investigated by NASA. The research to be presented includes: active control of aircraft fuselage sidewall transmission due to turbulent boundary layer or jet noise excitation, active control of interior tones due to propeller excitation of aircraft structures, and adaptive stiffening of structures for noise, vibration, and fatigue control. Work on actuator technology ranging from piezoelectrics, shape memory actuators, and fluidic actuators will be described including applications. Control system technology will be included that is experimentally based, real-time, and adaptive.

Using Simulation Technique to overcome the multi-collinearity problem for estimating fuzzy linear regression parameters.

NASA Astrophysics Data System (ADS)

Mansoor Gorgees, Hazim; Hilal, Mariam Mohammed

2018-05-01

Fatigue cracking is one of the common types of pavement distresses and is an indicator of structural failure; cracks allow moisture infiltration, roughness, may further deteriorate to a pothole. Some causes of pavement deterioration are: traffic loading; environment influences; drainage deficiencies; materials quality problems; construction deficiencies and external contributors. Many researchers have made models that contain many variables like asphalt content, asphalt viscosity, fatigue life, stiffness of asphalt mixture, temperature and other parameters that affect the fatigue life. For this situation, a fuzzy linear regression model was employed and analyzed by using the traditional methods and our proposed method in order to overcome the multi-collinearity problem. The total spread error was used as a criterion to compare the performance of the studied methods. Simulation program was used to obtain the required results.

NASA - easyJet Collaboration on the Human Factors Monitoring Program (HFMP) Study

NASA Technical Reports Server (NTRS)

Srivistava, Ashok N.; Barton, Phil

2012-01-01

This is the first annual report jointly prepared by NASA and easyJet on the work performed under the agreement to collaborate on a study of the many factors entailed in flight - and cabin-crew fatigue and documenting the decreases in performance associated with fatigue. The objective of this Agreement is to generate reliable, automated procedures that improve understanding of the levels and characteristics of flight - and cabin-crew fatigue factors, both latent and proximate, whose confluence will likely result in unacceptable flight crew performance. This study entails the analyses of numerical and textual data collected during operational flights. NASA and easyJet are both interested in assessing and testing NASA s automated capabilities for extracting operationally significant information from very large, diverse (textual and numerical) databases, much larger than can be handled practically by human experts.

Second Interim Report NASA - easyJet Collaboration on the Human Factors Monitoring Program (HFMP) Study

NASA Technical Reports Server (NTRS)

Srivistava, Ashok N.; Barton, Phil

2012-01-01

This is the second interim report jointly prepared by NASA and easyJet on the work performed under the agreement to collaborate on a study of the factors entailed in flight and cabin-crew fatigue, and decreases in performance associated with fatigue. The objective of this Agreement is to generate reliable procedures that aid in understanding the levels and characteristics of flight and cabin-crew fatigue factors, both latent and proximate, whose confluence will likely result in unacceptable crew performance. This study entails the analyses of numerical and textual data collected during operational flights. NASA and easyJet are both interested in assessing and testing NASA s automated capabilities for extracting operationally significant information from very large, diverse (textual and numerical) databases; much larger than can be handled practically by human experts.

Non-pharmacological interventions to manage fatigue and psychological stress in children and adolescents with cancer: an integrative review.

PubMed

Lopes-Júnior, L C; Bomfim, E O; Nascimento, L C; Nunes, M D R; Pereira-da-Silva, G; Lima, R A G

2016-11-01

Cancer-related fatigue (CRF) is the most stressful and prevalent symptom in paediatric oncology patients. This integrative review aimed to identify, analyse and synthesise the evidence of non-pharmacological intervention studies to manage fatigue and psychological stress in a paediatric population with cancer. Eight electronic databases were used for the search: PubMed, Web of Science, CINAHL, LILACS, EMBASE, SCOPUS, PsycINFO and the Cochrane Library. Initially, 273 articles were found; after the exclusion of repeated articles, reading of the titles, abstracts and the full articles, a final sample of nine articles was obtained. The articles were grouped into five categories: physical exercise, healing touch, music therapy, therapeutic massage, nursing interventions and health education. Among the nine studies, six showed statistical significance regarding the fatigue and/or stress levels, showing that the use of the interventions led to symptoms decrease. The most frequently tested intervention was programmed physical exercises. It is suggested that these interventions are complementary to conventional treatment and that their use can indicate an improvement in CRF and psychological stress. © 2015 John Wiley & Sons Ltd.

[Effects of Foot-Reflexology Massage on Fatigue, Stress and Postpartum Depression in Postpartum Women].

PubMed

Choi, Mi Son; Lee, Eun Ja

2015-08-01

To identify the effects of foot reflexology massage on fatigue, stress and depression of postpartum women. A nonequivalent control group pre-post design was used. A total of 70 women in a postpartum care center were recruited and were assigned to the experimental group (35) or control group (35). Foot reflexology massage was provided to the experimental group once a day for three days. Data were collected before and after the intervention program which was carried out from December, 2013 to February, 2014. Data were analyzed using Chi-square test, Fisher's exact test, and t-test. The level of fatigue in the experimental group was significantly lower than the control group (t=-2.74, p=.008). The level of cortisol in the urine of women in the experimental group was significantly lower than the control group (t=-2.19, p=.032). The level of depression in the experimental group was significantly lower than the control group (t=-3.00, p=.004). The results show that the foot reflexology massage is an effective nursing intervention to relieve fatigue, stress, and depression for postpartum women.

Thermal-Mechanical Stress Analysis of PWR Pressure Vessel and Nozzles under Grid Load-Following Mode: Interim Report on the Effect of Cyclic Hardening Material Properties and Pre-existing Cracks on Stress Analysis Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohanty, Subhasish; Soppet, William; Majumdar, Saurin

This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable under the work package for environmentally assisted fatigue as part of DOE’s Light Water Reactor Sustainability Program. In a previous report (September 2015), we presented tensile and fatigue test data and related hardening material properties for 508 low-alloys steel base metal and other reactor metals. In this report, we present thermal-mechanical stress analysis of the reactor pressure vessel and its hot-leg and cold-leg nozzles based on estimated material properties. We also present results frommore » thermal and thermal-mechanical stress analysis under reactor heat-up, cool-down, and grid load-following conditions. Analysis results are given with and without the presence of preexisting cracks in the reactor nozzles (axial or circumferential crack). In addition, results from validation stress analysis based on tensile and fatigue experiments are reported.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

MANDELL, JOHN F.; SAMBORSKY, DANIEL D.; CAIRNS, DOUGLAS

This report presents the major findings of the Montana State University Composite Materials Fatigue Program from 1997 to 2001, and is intended to be used in conjunction with the DOE/MSU Composite Materials Fatigue Database. Additions of greatest interest to the database in this time period include environmental and time under load effects for various resin systems; large tow carbon fiber laminates and glass/carbon hybrids; new reinforcement architectures varying from large strands to prepreg with well-dispersed fibers; spectrum loading and cumulative damage laws; giga-cycle testing of strands; tough resins for improved structural integrity; static and fatigue data for interply delamination; andmore » design knockdown factors due to flaws and structural details as well as time under load and environmental conditions. The origins of a transition to increased tensile fatigue sensitivity with increasing fiber content are explored in detail for typical stranded reinforcing fabrics. The second focus of the report is on structural details which are prone to delamination failure, including ply terminations, skin-stiffener intersections, and sandwich panel terminations. Finite element based methodologies for predicting delamination initiation and growth in structural details are developed and validated, and simplified design recommendations are presented.« less

Effects of High Mean Stress on High-cycle Fatigue Behavior of PWA 1480

NASA Technical Reports Server (NTRS)

Majumdar, S.; Antolovich, S. D.; Milligan, W. W.

1985-01-01

PWA 1480 is a potential candidate material for use in the high-pressure fuel turbine blade of the space shuttle main engine. As an engine material it will be subjected to high-cycle fatigue loading superimposed on a high mean stress due to combined centrifugal and thermal loadings. The present paper describes the results obtained in an ongoing program at the Argonne National Laboratory, sponsored by NASA Lewis, to determine the effects of a high mean stress on the high-cycle fatigue behavior of this material. Straight-gauge high-cycle fatigue specimens, 0.2 inch in diameter and with the specimen axis in the 001 direction, were supplied by NASA Lewis. The nominal room temperature yield and ultimate strength of the material were 146 and 154 ksi, respectively. Each specimen was polished with 1-micron diamond paste prior to testing. However, the surface of each specimen contained many pores, some of which were as large as 50 micron. In the initial tests, specimens were subjected to axial-strain-controlled cycles. However, very little cyclic plasticity was observed.

[Counseling in the prevention of fatigue in psychiatric nurses].

PubMed

Greeff, M; Poggenpoel, M

1991-12-01

Nursing is a stressful activity and therefore it is necessary for nurses to develop effective coping mechanisms, or to strengthen existing ones in a healthy manner, in order to be capable of dealing with stress, arising from their personal and professional lives. It is, however, not solely stress itself which predisposes nurses to fatigue (physical, psychological and emotional exhaustion) but rather the chronic nature and excessive amount of stressors which place excessive demands on the energy resources and coping, mechanisms of nurses resulting in the ineffective handling of stress which in turn leads to the eventual development of fatigue. The detrimental results of this experience are, however, not confined to the nurse herself, but extends further to the patient and the organization. Thus, if fatigue is not controlled or dealt with, all parties and organizations concerned could suffer. This research covers the accompaniment function of the psychiatric nurse specialist in the prevention of fatigue in psychiatric nurses by strengthening their mental preparedness. As a possible solution to the experience of fatigue, a structured, accompanied program of three days was offered to a group of psychiatric nurses. The Solomon four group design was followed in order to eliminate influences on the subjects resulting from the completion of the self-evaluation scale as pre-test. The data which was obtained from the test results was statistically compared. Results showed that there was a definite decrease in the levels of fatigue experienced by the experimental group that received the structured accompanied programme, but no real change occurred in the control group that had merely been provided with relevant literature.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of exercise on fatigue, sleep, and performance: a randomized trial.

PubMed

Coleman, Elizabeth Ann; Goodwin, Julia A; Kennedy, Robert; Coon, Sharon K; Richards, Kathy; Enderlin, Carol; Stewart, Carol B; McNatt, Paula; Lockhart, Kim; Anaissie, Elias J

2012-09-01

To compare usual care with a home-based individualized exercise program (HBIEP) in patients receiving intensive treatment for multiple myeloma (MM)and epoetin alfa therapy. Randomized trial with repeated measures of two groups (one experimental and one control) and an approximate 15-week experimental period. Outpatient setting of the Myeloma Institute for Research and Therapy at the Rockfellow Cancer Center at the University of Arkansas for Medical Sciences. 187 patients with newly diagnosed MM enrolled in a separate study evaluating effectiveness of the Total Therapy regimen, with or without thalidomide. Measurements included the Profile of Mood States fatigue scale, Functional Assessment of Cancer Therapy-Fatigue, ActiGraph® recordings, 6-Minute Walk Test, and hemoglobin levels at baseline and before and after stem cell collection. Descriptive statistics were used to compare demographics and treatment effects, and repeated measures analysis of variance was used to determine effects of HBIEP. Fatigue, nighttime sleep, performance (aerobic capacity) as dependent or outcome measures, and HBIEP combining strength building and aerobic exercise as the independent variable. Both groups were equivalent for age, gender, race, receipt of thalidomide, hemoglobin levels, and type of treatment regimen for MM. No statistically significant differences existed among the experimental and control groups for fatigue, sleep, or performance (aerobic capacity). Statistically significant differences (p < 0.05) were found in each of the study outcomes for all patients as treatment progressed and patients experienced more fatigue and poorer nighttime sleep and performance (aerobic capacity). The effect of exercise seemed to be minimal on decreasing fatigue, improving sleep, and improving performance (aerobic capacity). Exercise is safe and has physiologic benefits for patients undergoing MM treatment; exercise combined with epoetin alfa helped alleviate anemia.

Health status among long-term breast cancer survivors suffering from higher levels of fatigue: a cross-sectional study.

PubMed

Álvarez-Salvago, Francisco; Galiano-Castillo, Noelia; Arroyo-Morales, Manuel; Cruz-Fernández, Mayra; Lozano-Lozano, Mario; Cantarero-Villanueva, Irene

2018-05-05

The aims of this study were to evaluate the health status of long-term breast cancer survivors (LTBCS) suffering from higher levels of fatigue, to highlight their needs, and to establish the key points of intervention support programs. A cross-sectional observational study was conducted at the Sport and Health Joint University Institute (iMUDS) between September 2016 and July 2017 with 80 LTBCS that were classified into non-fatigued (≤ 3.9) or fatigued (≥ 4) according to the Piper Fatigue Scale (PFS) total score. The instruments used were the European Organization for Research and Treatment of Cancer Core 30 and its breast cancer (BC) module, the Visual Analog Scale (VAS), the Brief Pain Inventory (BPI), the Scale for Mood Assessment (EVEA), the International Fitness Scale (IFIS), and the Charlson Comorbidity Index. The analysis revealed that 41.2% of LTBCS were considered moderately fatigued and showed significantly higher levels for the categories of "nausea and vomiting" (P = .005), "pain," "dyspnea" and "insomnia" (P < .001), "appetite loss" (P = .002), "financial difficulties" (P = .010), "systemic therapy side effects" (P < .001), "breast symptoms" and "arm symptoms" (P = .002), and "upset by hair loss" (P = .016). In addition, LTBCS presented significantly higher levels of pain in the affected and non-affected arm, "sadness-depression." "anxiety," "anger/hostility" (All: P < .001), and lower general physical fitness (P < .001). The rest of the variables did not show significant differences. LTBCS suffering from higher levels of fatigue had lower QoL, higher level of pain, worse mood state, and lower physical fitness.

Empathy and feelings of guilt experienced by nurses: A cross-sectional study of their role in burnout and compassion fatigue symptoms.

PubMed

Duarte, Joana; Pinto-Gouveia, José

2017-06-01

The main goal of this study was to explore the relationships between empathy, empathy-based pathogenic guilt and professional quality of life (burnout and compassion fatigue). We aim to test a model in which we hypothesize that when empathic feelings are related to pathogenic guilt, burnout and compassion fatigue symptoms may be increased. Empathy is at the core of nursing practice, and has been associated with positive outcomes not only for the healthcare provider but also for the patient. However, empathy is also at the core of guilt feelings that, when excessive and misdirected, can lead to pathogenic guilt beliefs. We focused on two types of empathy-based guilt characterized by excessive responsibility over others' well-being and how these can be related to professional quality of life. This study is a cross-sectional self-report survey. Data were collected during 2014 and 2015. Two hundred ninety-eight nurses from public hospitals in Portugal's north and center region were surveyed. Professional quality of life (burnout and compassion fatigue), empathy, and empathy-based guilt were measured using validated self-report measures. Correlation analyses showed that empathy-based guilt was positively associated with empathy, and with burnout and compassion fatigue. Results from multiple mediation models further indicated when empathy is associated with empathy-based guilt, this leads to greater levels of burnout and compassion fatigue. Given the nature of their work, nurses who experience pathogenic guilt feelings may have compromised well-being, and this should be addressed in training programs aiming at preventing or treating burnout and compassion fatigue. Copyright © 2017 Elsevier Inc. All rights reserved.

Fatigue-Related Countermeasures for Long-Duration Exploration Missions

NASA Technical Reports Server (NTRS)

Whitmire, A.; Johnston, S.; Sipes, W.

2014-01-01

The NASA Human Research Program's (HRP) Behavioral Health and Performance Element (BHP) supports and conducts research to mitigate deleterious outcomes related to fatigue, sleep loss, circadian desynchronization, and work overload. Objective evidence indicates that within the context of the International Space Station (ISS), sleep is reduced and there is circadian misalignment. Despite chronic sleep loss and high workloads; however, astronauts successfully complete their missions. Contributing to their success is not only the tremendous skills and capabilities of each astronaut, but also the collaborative team efforts amongst the crew, between flight and ground crews, and through real-time care provided by medical personnel. It is anticipated that risks to human health and performance will increase in the context of exploration missions, where crewmembers will venture to deep space for extended durations and in small vehicles with limited communication with home. Hence, fatigue-related countermeasures are being developed and/or validated that include unobtrusive monitoring technologies to detect fatigue-related performance decrements, environmental countermeasures, and sleep education and training for flight and ground crews. Given that fatigue is an issue in current ISS missions, the BHP works collaboratively with Space Medicine operations to collect data in the operational environment, to validate fatigue-related countermeasures, and provide evidence-based mitigations. Our presentation will summarize fatigue-related operational research that is underway through NASA's BHP in partnership with its operational counterparts. Efforts include studies evaluating the effects of hypnotics, lighting protocols as countermeasures for circadian entrainment, and investigations involving education and training. This presentation will further identify, based on flight and terrestrial evidence, additional sleep and circadian countermeasures that may still be needed to support exploration missions. Lessons learned from transitioning research deliverables into ISS operations will also be discussed.

Understanding and Counteracting Fatigue in Flight Crews

NASA Technical Reports Server (NTRS)

Mallis, Melissa; Neri, David; Rosekind, Mark; Gander, Philippa; Caldwell, John; Graeber, Curtis

2007-01-01

The materials included in the collection of documents describe the research of the NASA Ames Fatigue Countermeasures Group (FCG), which examines the extent to which fatigue, sleep loss, and circadian disruption affect flight-crew performance. The group was formed in 1980 in response to a Congressional request to examine a possible safety problem of uncertain magnitude due to transmeridian flying and a potential problem due to fatigue in association with various factors found in air-transport operations and was originally called the Fatigue/Jet Lag Program. The goals of the FCG are: (1) the development and evaluation of strategies for mitigating the effects of sleepiness and circadian disruption on pilot performance levels; (2) the identification and evaluation of objective approaches for the prediction of alertness changes in flight crews; and (3) the transfer and application of research results to the operational field via classes, workshops, and safety briefings. Some of the countermeasure approaches that have been identified to be scientifically valid and operationally relevant are brief naps (less than 40 min) in the cockpit seat and 7-min activity breaks, which include postural changes and ambulation. Although a video-based alertness monitor based on slow eyelid closure shows promise in other operational environments, research by the FCG has demonstrated that in its current form at the time of this reporting, it is not feasible to implement it in the cockpit. Efforts also focus on documenting the impact of untreated fatigue on various types of flight operations. For example, the FCG recently completed a major investigation into the effects of ultra-long-range flights (20 continuous hours in duration) on the alertness and performance of pilots in order to establish a baseline set of parameters against which the effectiveness of new ultra-long-range fatigue remedies can be judged.

What kind of diagnosis in a case of mobbing: post-traumatic stress disorder or adjustment disorder?

PubMed Central

Signorelli, Maria Salvina; Costanzo, Maria Cristina; Cinconze, Maria; Concerto, Carmen

2013-01-01

Over the last decade a consistent increase in stress-related psychological consequences at the workplace, usually called ‘mobbing’, has been seen. It claimed physical, psychical and social distress as its victims, leading to an increased incidence of many illnesses, such as psychosomatic disorders (ache, high blood pressure, chronic fatigue and insomnia) and psychiatric disturbances (high level of anxiety, depression and suicidal attempts). It was recently demonstrated that mobbing is significantly widespread among healthcare workers, especially among female nurses. In this report, we illustrate the case of a nurse who, after a brilliant career, underwent mobbing at the workplace, showing depression, anxiety and sleep disorders that required hospitalisation and a substantial intervention. PMID:23761569

Fibromyalgia Syndrome in Need of Effective Treatments

PubMed Central

Tsilioni, Irene; Arbetman, Lauren; Panagiotidou, Smaro; Stewart, Julia M.; Gleason, Rae M.; Russell, Irwin J.

2015-01-01

Fibromyalgia syndrome (FMS) is a chronic, idiopathic condition of widespread musculoskeletal pain, affecting primarily women. It is clinically characterized by chronic, nonarticular pain and a heightened response to pressure along with sleep disturbances, fatigue, bowel and bladder abnormalities, and cognitive dysfunction. The diagnostic criteria have changed repeatedly, and there is neither a definitive pathogenesis nor reliable diagnostic or prognostic biomarkers. Clinical and laboratory studies have provided evidence of altered central pain pathways. Recent evidence suggests the involvement of neuroinflammation with stress peptides triggering the release of neurosenzitizing mediators. The management of FMS requires a multidimensional approach including patient education, behavioral therapy, exercise, and pain management. Here we review recent data on the pathogenesis and propose new directions for research and treatment. PMID:26306765

COMMERCIAL SUPERSONIC TRANSPORT PROGRAM. PHASE II-C REPORT. HIGH STRENGTH STEEL EVALUATION FOR SUPERSONIC AIRCRAFT.

DTIC Science & Technology

JET TRANSPORT AIRCRAFT, *AIRFRAMES, SUPERSONIC AIRCRAFT, STEEL , STRUCTURAL PROPERTIES, FRACTURE(MECHANICS), FATIGUE(MECHANICS), STRESS CORROSION...MICROPHOTOGRAPHY, HIGH TEMPERATURE, NICKEL ALLOYS, COBALT ALLOYS, CARBON, BAINITE , COMMERCIAL AIRCRAFT.

Creep fatigue life prediction for engine hot section materials (ISOTROPIC)

NASA Technical Reports Server (NTRS)

Nelson, R. S.; Schoendorf, J. F.; Lin, L. S.

1986-01-01

The specific activities summarized include: verification experiments (base program); thermomechanical cycling model; multiaxial stress state model; cumulative loading model; screening of potential environmental and protective coating models; and environmental attack model.

Programs To Support You During Chemotherapy

ClinicalTrials.gov

2018-05-24

Depression; Fatigue; Stage IIA Colorectal Cancer; Stage IIB Colorectal Cancer; Stage IIC Colorectal Cancer; Stage IIIA Colorectal Cancer; Stage IIIB Colorectal Cancer; Stage IIIC Colorectal Cancer; Stage IVA Colorectal Cancer; Stage IVB Colorectal Cancer

Graphite fiber reinforced thermoplastic resins

NASA Technical Reports Server (NTRS)

Navak, R. C.

1977-01-01

The results of a program designed to optimize the fabrication procedures for graphite thermoplastic composites are described. The properties of the composites as a function of temperature were measured and graphite thermoplastic fan exit guide vanes were fabricated and tested. Three thermoplastics were included in the investigation: polysulfone, polyethersulfone, and polyarylsulfone. Type HMS graphite was used as the reinforcement. Bending fatigue tests of HMS graphite/polyethersulfone demonstrated a gradual shear failure mode which resulted in a loss of stiffness in the specimens. Preliminary curves were generated to show the loss in stiffness as a function of stress and number of cycles. Fan exit guide vanes of HMS graphite polyethersulfone were satisfactorily fabricated in the final phase of the program. These were found to have stiffness and better fatigue behavior than graphite epoxy vanes which were formerly bill of material.

Materials research for high-speed civil transport and generic hypersonics: Composites durability

NASA Technical Reports Server (NTRS)

Allen-Lilly, Heather; Cregger, Eric; Hoffman, Daniel; Mccool, Jim

1995-01-01

This report covers a portion of an ongoing investigation of the durability of composites for the High Speed Civil Transport (HSCT) program. Candidate HSCT composites need to possess the high-temperature capability required for supersonic flight. This program was designed to initiate the design, analysis, fabrication, and testing of equipment intended for use in validating the long-term durability of materials for the HSCT. This equipment includes thermally actuated compression and tension fixtures, hydraulic-actuated reversible load fixtures, and thermal chambers. This equipment can be used for the durability evaluation of both composite and adhesive materials. Thermally actuated fixtures are recommended for fatigue cycling when long-term thermomechanical fatigue (TMF) data are required on coupon-sized tension or compression specimens. Long term durability testing plans for polymer matrix composite specimens are included.

Biofuels, Biolubricants and the BioPreferred(SM) Program

USDA-ARS?s Scientific Manuscript database

The BioPreferred(SM) Program is a U.S. government initiative intended to encourage the development and widespread use of biofuels, biolubricants, and other biobased products in the U.S. The program consists of the preferred procurement and the voluntary labeling programs. Companies wishing to have t...

Compassion fatigue, burnout and compassion satisfaction among family physicians in the Negev area - a cross-sectional study.

PubMed

El-Bar, Nurit; Levy, Amalia; Wald, Hedy S; Biderman, Aya

2013-08-15

Compassion fatigue among health care professionals has gained interest over the past decade. Compassion fatigue, as well as burnout, has been associated with depersonalization and suboptimal patient care. Professional caregivers in general are exposed to the risk of compassion fatigue (CF), burnout (BO) and low levels of compassion satisfaction (CS). While CF has been studied in health care professionals, few publications address its incidence among family physicians, specifically. The objectives of this study were to assess the prevalence and severity of CF among family practitioners (FPs) in the Negev (Israel's southern region), evaluating the correlations between CF, BO and CS and their relations with socio-demographic variables and work related characteristics. Self-report anonymous Compassion Satisfaction and Fatigue Test questionnaires (CSFT) measuring CF, BO, and CS were distributed among 194 family physicians at Clalit Health Services clinics in the Negev between July 2007 and April 2008. Correlations between CF, BO and CS were assessed. Multivariable logistic regression models with backward elimination were constructed. 128 (66%) physicians responded. 46.1% of respondents scored extremely high and high for CF, 21.1% scored low for CS and 9.4% scored high for BO. Strong correlations were found between BO and CF (r = 0.769, p < 0.001), and between BO and CS (r = -0.241, p = 0.006), but no correlation was found between CS and CF. The logistic regression model showed that the only factor associated with a significantly increased risk for CF was former immigration to Israel. Increased risk for BO was associated with female gender, history of personal trauma and lack of academic affiliation. Higher CS was associated with holding management positions and teaching residents. Family physicians in the Negev are at high risk for CF, with the potential for CF- associated patient dissatisfaction, compromised patient safety and increased medical error. We propose creation of a CF educational and early intervention treatment program for family physicians and other health care professionals. Such programs would train facilitators of physician well-being and resiliency building. We also recommend analyzing contributing variables and organizational factors related to higher CF. Policy recommendations include integrating such programs within required risk management continuing medical education.

Compassion fatigue, burnout and compassion satisfaction among family physicians in the Negev area - a cross-sectional study

PubMed Central

2013-01-01

Background Compassion fatigue among health care professionals has gained interest over the past decade. Compassion fatigue, as well as burnout, has been associated with depersonalization and suboptimal patient care. Professional caregivers in general are exposed to the risk of compassion fatigue (CF), burnout (BO) and low levels of compassion satisfaction (CS). While CF has been studied in health care professionals, few publications address its incidence among family physicians, specifically. The objectives of this study were to assess the prevalence and severity of CF among family practitioners (FPs) in the Negev (Israel’s southern region), evaluating the correlations between CF, BO and CS and their relations with socio-demographic variables and work related characteristics. Methods Self-report anonymous Compassion Satisfaction and Fatigue Test questionnaires (CSFT) measuring CF, BO, and CS were distributed among 194 family physicians at Clalit Health Services clinics in the Negev between July 2007 and April 2008. Correlations between CF, BO and CS were assessed. Multivariable logistic regression models with backward elimination were constructed. Results 128 (66%) physicians responded. 46.1% of respondents scored extremely high and high for CF, 21.1% scored low for CS and 9.4% scored high for BO. Strong correlations were found between BO and CF (r = 0.769, p < 0.001), and between BO and CS (r = −0.241, p = 0.006), but no correlation was found between CS and CF. The logistic regression model showed that the only factor associated with a significantly increased risk for CF was former immigration to Israel. Increased risk for BO was associated with female gender, history of personal trauma and lack of academic affiliation. Higher CS was associated with holding management positions and teaching residents. Conclusions and policy recommendations Family physicians in the Negev are at high risk for CF, with the potential for CF- associated patient dissatisfaction, compromised patient safety and increased medical error. We propose creation of a CF educational and early intervention treatment program for family physicians and other health care professionals. Such programs would train facilitators of physician well-being and resiliency building. We also recommend analyzing contributing variables and organizational factors related to higher CF. Policy recommendations include integrating such programs within required risk management continuing medical education. PMID:23947591

Gender differences in chronic fatigue syndrome.

PubMed

Faro, Mònica; Sàez-Francás, Naia; Castro-Marrero, Jesús; Aliste, Luisa; Fernández de Sevilla, Tomás; Alegre, José

2016-01-01

Chronic fatigue syndrome (CFS) is a chronic condition that predominantly affects women. To date, there are few epidemiologic studies on CFS in men. The objective of the study was to assess whether there are gender-related differences in CFS, and to define a clinical phenotype in men. A prospective, cross-sectional cohort study was conducted including CFS patients at the time of diagnosis. Sociodemographic data, clinical variables, comorbid phenomena, fatigue, pain, anxiety/depression, and health quality of life, were assessed in the CFS population. A comparative study was also conducted between genders. The study included 1309 CFS patients, of which 119 (9.1%) were men. The mean age and symptoms onset were lower in men than women. The subjects included 30% single men vs. 15% single women, and 32% of men had specialist work vs. 20% of women. The most common triggering factor was an infection. Widespread pain, muscle spasms, dizziness, sexual dysfunction, Raynaud's phenomenon, morning stiffness, migratory arthralgias, drug and metals allergy, and facial oedema were less frequent in men. Fibromyalgia was present in 29% of men vs. 58% in women. The scores on physical function, physical role, and overall physical health of the SF-36 were higher in men. The sensory and affective dimensions of pain were lower in men. The clinical phenotype of the men with CFS was young, single, skilled worker, and infection as the main triggering agent. Men had less pain and less muscle and immune symptoms, fewer comorbid phenomena, and a better quality of life. Copyright © 2014 Elsevier España, S.L.U. y Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

Androgen deprivation therapy for prostate cancer: long-term safety and patient outcomes

PubMed Central

Ahmadi, Hamed; Daneshmand, Siamak

2014-01-01

Androgen deprivation therapy (ADT) constitutes the first-line treatment for patients with locally advanced tumors, recurrent or metastatic disease. Given its widespread use, clinicians should be familiar with common side effects of this treatment. This review focuses on common side effects of ADT and available treatment options to control the side effects. Also, it briefly compares continuous ADT with other therapeutic approaches for androgen deprivation in prostate cancer patients. Similar to hormonal medications, newer non-hormonal therapeutic options including gabapentin and acupuncture have at best moderate effect in controlling hot flashes in patients on ADT. Supervised and/or home exercise programs significantly improve ADT-related fatigue, metabolic/cardiovascular side effects, and cognitive dysfunction. Denosumab, a human monoclonal antibody against RANK-L, is more effective than bisphosphonates in preventing skeletal-related events in patients with metastatic or castrate-resistant prostate cancer and unlike bisphosphonates, it can also reduce the risk of vertebral fractures in men receiving ADT for non-metastatic prostate cancer. Toremifene, a selective estrogen receptor inhibitor, has dual beneficial effects on ADT-related osteoporosis and metabolic dysfunction. Metformin coupled with lifestyle modification is also a well-tolerated treatment for metabolic changes during ADT. While producing similar oncological outcomes, intermittent ADT is associated with higher quality of life in patients under ADT by improving bone health, less metabolic and hematologic complications, and fewer hot flashes and sexual dysfunction events. PMID:25045284

Local and National Testing in the UK: The Last Ten Years.

ERIC Educational Resources Information Center

Gipps, Caroline; Goldstein, Harvey

New developments in testing in the United Kingdom (UK) since 1965 are described. Standardized testing at the local level declined dramatically with the widespread introduction of comprehensive secondary education. However, in the late 1970's widespread local testing programs were re-introduced for the purposes of monitoring student progress,…

Economic Development and the University: A Case Study of a Failed Program.

ERIC Educational Resources Information Center

Senter, Richard, Jr.

1996-01-01

The role of the university in programs to stimulate economic development is examined, and the case of one such program that failed is described. Problems within the program included financial losses in large projects, corruption, widespread public criticism, and criminal convictions of two top program officers. Possible solutions, including…

Evaluation of the Accelerated Reader Program in Chesapeake, VA, Public Schools

ERIC Educational Resources Information Center

Chase, Elaine; Goodin, Penny; Nichols, W. Randolph

2010-01-01

The Accelerated Reader program from Renaissance Learning Inc. is a popular program implemented in elementary and middle schools across the country that encourages students to read and monitors their progress in the program. Despite its widespread use and popularity, there have been some questions about the program's effectiveness at increasing…

E-Mentoring for Social Equity: Review of Research to Inform Program Development

ERIC Educational Resources Information Center

Single, Peg Boyle; Single, Richard M.

2005-01-01

The advent of user-friendly email programs and web browsers created possibilities for widespread use of e-mentoring programs. In this review of the research, we presented the history of e-mentoring programs and defined e-mentoring and structured e-mentoring programs, focusing on large-scale e-mentoring programs that addressed issues of social…

Effects of Sex and Fatigue on Biomechanical Measures During the Drop-Jump Task in Children

PubMed Central

Briem, Kristín; Jónsdóttir, Kolbrún Vala; Árnason, Árni; Sveinsson, Þórarinn

2017-01-01

Background: Female athletes have a higher rate of anterior cruciate ligament (ACL) injury than males from adolescence and into maturity, which is suggested to result from sex-specific changes in dynamic movement patterns with maturation. Few studies have studied movement strategies and response to fatigue in children. Purpose: To evaluate the effect of fatigue on biomechanical variables associated with increased risk for ACL injury during a drop-jump (DJ) performance in children. Study Design: Controlled laboratory study. Methods: A total of 116 children (mean age, 10.4 years) were recruited from local sports clubs and performed 5 repetitions of a DJ task before and after a fatigue protocol. Kinematic and kinetic data from initial contact (IC) to the first peak vertical ground reaction force (vGRF) were analyzed for both limbs, including limb and fatigue as within-subject factors for analyses between boys and girls. Pearson correlation coefficients were calculated to identify associations between variables of interest. Results: Girls demonstrated greater peak vGRF values than boys (by 8.1%; P < .05), there were greater peak vGRF values for the right limb than the left (by 6.2%; P < .001), and fatigue led to slightly greater values (P < .05). Although weak, the correlation between peak vGRF values and knee flexion excursion was stronger for girls (r = –0.20) than boys (r = –0.08) (P < .006). Fatigue resulted in greater knee flexion angles at IC and less excursion during landing, more so for girls (by 6.1° vs 1.4°; interaction, P < .001), although the knee flexion moment was generally lowered by fatigue (P < .001). Limb asymmetry in knee flexion moments was more pronounced for boys than for girls (interaction, P < .05), contrary to that seen in frontal plane knee moments, where asymmetry was much greater in girls than boys (interaction, P < .001). Conclusion: Even as young athletes, girls and boys seem to adopt dissimilar movement strategies and are differently affected by fatigue. Clinical Relevance: Injury prevention programs should be considered at an earlier age in an effort to lower the risk of ACL injury in athletes. PMID:28203593

Severe eosinophilic colitis caused by neuropathic agents in a patient with chronic fatigue syndrome and functional abdominal pain: case report and review of the literature.

PubMed

Fragkos, Konstantinos C; Barragry, John; Fernando, Charisma Shahi; Novelli, Marco; Begent, Joanna; Zárate-Lopez, Natalia

2018-06-01

Eosinophilic colitis is a rare clinical condition that belongs to the group of eosinophilic gastrointestinal disorders. Its occurrence can be primary or secondary to infection, medications, or autoimmune/hematological conditions. We present a case of a young female adult with severe chronic fatigue syndrome, widespread chronic pain, including functional abdominal pain, who developed severe eosinophilic colitis following successive treatments with gabapentin and pregabalin. On both occasions, symptoms manifested as abdominal pain, diarrhea, and eosinophilia and improved upon discontinuation of the medications. Magnetic resonance imaging of the small bowel demonstrated an ascending colon colitis, and endoscopic investigations confirmed florid colitis mainly in the ascending colon with biopsies demonstrating a dense eosinophilic infiltrate with micro-abscesses. Serum eosinophil counts correlated well with the timing of the agents' administration. There was no other organ involvement. Symptoms improved upon discontinuation of the drugs and steroid administration. Eosinophilic colitis is an exceptionally rare entity and its mechanism of action is still unclear. Suspicion of eosinophilic colitis should be raised if a patient presents with abdominal pain, diarrhea, and peripheral eosinophilia following treatment with pregabalin or gabapentin. © Georg Thieme Verlag KG Stuttgart · New York.

Comparison of education and balneotherapy efficacy in patients with fibromyalgia syndrome: A randomized, controlled clinical study.

PubMed

Koçyiğit, Burhan Fatih; Gür, Ali; Altındağ, Özlem; Akyol, Ahmet; Gürsoy, Savaş

2016-04-01

Fibromyalgia is a disease characterized by chronic, widespread pain. Pharmacological and non-pharmacological treatment methods are used. The aim of the present study was to determine the effect of balneotherapy on treatment of fibromyalgia syndrome, compared with education alone. A total of 66 patients diagnosed with fibromyalgia syndrome were randomly separated into balneotherapy and control groups. Patients in both groups were informed about fibromyalgia syndrome. In addition, the balneotherapy group received 21 sessions of spa treatment with 34.8 °C thermomineral water, attending the spa 5 days a week. Patients were evaluated by visual analogue scale, tender point count, fibromyalgia impact questioning, and modified fatigue impact scale at initiation of treatment on the 15th day, 1st month, 3rd month, and 6th month. Evaluations were performed by the same doctor. Statistically significant improvement was detected in all parameters, compared to starting evaluation, in both groups. Most improved results among all parameters were observed in the balneotherapy group on the first 3-month follow-up. In addition, all parameters beyond tender point count and modified fatigue impact were improved on 6-month follow-up. It was concluded that addition of balneotherapy to patient education has both short- and long-term beneficial effects on female patients with fibromyalgia.

Integrated Review of the Association of Cytokines with Fibromyalgia and Fibromyalgia Core Symptoms

PubMed Central

Lyon, Debra

2013-01-01

Fibromyalgia (FMS) is a chronic widespread pain and fatigue syndrome that affects 3 to 6 million adults in the United States. Core symptoms of fibromyalgia include pain, fatigue, and mood and sleep disturbances. To date, consensus has not been reached among researchers regarding the pathogenesis of FMS nor the specific role of cytokine activation on the neuroendocrine-immune response patterns in persons with FMS. The purpose of this article is to describe and synthesize the results of research studies focused on the relationship between cytokines and FMS and among cytokines and core symptoms of FMS. There is some support in the literature for relationships among FMS symptoms and cytokines; however, there are discrepant findings related to whether pro- and anti-inflammatory cytokines are elevated or reduced in persons with FMS and whether or not their levels correlate with the core symptoms of this disorder. Although the use of cytokine biomarkers must be considered exploratory at this time due to the lack of consistent empirical findings, biobehavioral research focused on understanding the relationship of FMS with cytokines may lead to a better understanding of this complex syndrome. This knowledge may ultimately contribute to the development of interventions for symptom management that address not only the symptom manifestation but also a biological mediator of symptoms. PMID:19933683

Yoga-Based Rehabilitation Program in Reducing Physical and Emotional Side Effects in Patients With Cancer

ClinicalTrials.gov

2017-01-23

Alopecia; Anxiety; Breast Carcinoma; Cognitive Side Effects of Cancer Therapy; Colorectal Carcinoma; Depression; Fatigue; Lung Carcinoma; Nausea and Vomiting; Pain; Psychological Impact of Cancer; Sleep Disorder; Weight Change

The ITS/CVO mainstreaming program

DOT National Transportation Integrated Search

1998-11-01

Researchers sought to determine if fatigue is an equally important factor in influencing the safety of local/short haul truck operations as it is in influencing the safety of long-haul commercial vehicle operations. Accordingly, researchers conducted...

Designing and Implementing Effective In-School Alternatives to Suspension.

ERIC Educational Resources Information Center

Mizell, M. Hayes

Because of widespread disillusion with suspension as a discipline procedure, school officials are developing inschool alternative programs. Institution of such a program must begin with reflection about how current disciplinary programs are succeeding or failing. The primary purposes of the program must include helping the child and identifying…

Crack Growth Behavior in the Threshold Region for High Cycle Fatigue Loading

NASA Technical Reports Server (NTRS)

Forman, Royce G.; Figert, J.; Beek, J.; Ventura, J.; Martinez, J.; Samonski, F.

2011-01-01

This presentation describes results obtained from a research project conducted at the NASA Johnson Space Center (JSC) that was jointly supported by the FAA Technical Center and JSC. The JSC effort was part of a multi-task FAA program involving several U.S. laboratories and initiated for the purpose of developing enhanced analysis tools to assess damage tolerance of rotorcraft and aircraft propeller systems. The research results to be covered in this presentation include a new understanding of the behavior of fatigue crack growth in the threshold region. This behavior is important for structural life analysis of aircraft propeller systems and certain rotorcraft structural components (e.g., the mast). These components are often designed to not allow fatigue crack propagation to exceed an experimentally determined fatigue crack growth threshold value. During the FAA review meetings for the program, disagreements occurred between the researchers regarding the observed fanning (spread between the da/dN curves of constant R) in the threshold region at low stress ratios, R. Some participants believed that the fanning was a result of the ASTM load shedding test method for threshold testing, and thus did not represent the true characteristics of the material. If the fanning portion of the threshold value is deleted or not included in a life analysis, a significant penalty in the calculated life and design of the component would occur. The crack growth threshold behavior was previously studied and reported by several research investigators in the time period: 1970-1980. Those investigators used electron microscopes to view the crack morphology of the fatigue fracture surfaces. Their results showed that just before reaching threshold, the crack morphology often changed from a striated to a faceted or cleavage-like morphology. This change was reported to have been caused by particular dislocation properties of the material. Based on the results of these early investigations, a program was initiated at JSC to repeat these examinations on a number of aircraft structural alloys that were currently being tested for obtaining fatigue crack growth properties. These new scanning electron microscope (SEM) examinations of the fatigue fracture faces confirmed the change in crack morphology in the threshold crack tip region. In addition, SEM examinations were further performed in the threshold crack-tip region before breaking the specimens open (not done in the earlier published studies). In these examinations, extensive crack forking and even 90-degree crack bifurcations were found to have occurred in the final threshold crack-tip region. The forking and bifurcations caused numerous closure points to occur that prevented full crack closure in the threshold region, and thus were the cause of the fanning at low-R values. Therefore, we have shown that the fanning behavior was caused by intrinsic dislocation properties of the different alloy materials and were not the result of a plastic wake that remains from the load-shedding test phase. Also, to accommodate the use of da/dN data which includes fanning at low R-values, an updated fanning factor term has been developed and will be implemented into the NASGRO fatigue crack growth software. The term can be set to zero if it is desired that the fanning behavior is not be modeled for particular cases, such as when fanning is not a result of the intrinsic properties of a material.

Biaxial tests of flat graphite/epoxy laminates

NASA Technical Reports Server (NTRS)

Liebowitz, H.; Jones, D. L.

1981-01-01

The influence of biaxially applied loads on the strength of composite materials containing holes was analyzed. The analysis was performed through the development of a three dimensional, finite element computer program that is capable of evaluating fiber breakage, delamination, and matrix failure. Realistic failure criteria were established for each of the failure modes, and the influence of biaxial loading on damage accumulation under monotonically increasing loading was examined in detail. Both static and fatigue testing of specially designed biaxial specimens containing central holes were performed. Static tests were performed to obtain an understanding of the influence of biaxial loads on the fracture strength of composite materials and to provide correlation with the analytical predictions. The predicted distributions and types of damage are in reasonable agreement with the experimental results. A number of fatigue tests were performed to determine the influence of cyclic biaxial loads on the fatigue life and residual strength of several composite laminates.

Development of a decision support system for analysis and solutions of prolonged standing in the workplace.

PubMed

Halim, Isa; Arep, Hambali; Kamat, Seri Rahayu; Abdullah, Rohana; Omar, Abdul Rahman; Ismail, Ahmad Rasdan

2014-06-01

Prolonged standing has been hypothesized as a vital contributor to discomfort and muscle fatigue in the workplace. The objective of this study was to develop a decision support system that could provide systematic analysis and solutions to minimize the discomfort and muscle fatigue associated with prolonged standing. The integration of object-oriented programming and a Model Oriented Simultaneous Engineering System were used to design the architecture of the decision support system. Validation of the decision support system was carried out in two manufacturing companies. The validation process showed that the decision support system produced reliable results. The decision support system is a reliable advisory tool for providing analysis and solutions to problems related to the discomfort and muscle fatigue associated with prolonged standing. Further testing of the decision support system is suggested before it is used commercially.