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Sample records for allostatic load parameters

  1. Allostatic Load and Preterm Birth

    PubMed Central

    Olson, David M.; Severson, Emily M.; Verstraeten, Barbara S. E.; Ng, Jane W. Y.; McCreary, J. Keiko; Metz, Gerlinde A. S.

    2015-01-01

    Preterm birth is a universal health problem that is one of the largest unmet medical needs contributing to the global burden of disease. Adding to its complexity is that there are no means to predict who is at risk when pregnancy begins or when women will actually deliver. Until these problems are addressed, there will be no interventions to reduce the risk because those who should be treated will not be known. Considerable evidence now exists that chronic life, generational or accumulated stress is a risk factor for preterm delivery in animal models and in women. This wear and tear on the body and mind is called allostatic load. This review explores the evidence that chronic stress contributes to preterm birth and other adverse pregnancy outcomes in animal and human studies. It explores how allostatic load can be used to, firstly, model stress and preterm birth in animal models and, secondly, how it can be used to develop a predictive model to assess relative risk among women in early pregnancy. Once care providers know who is in the highest risk group, interventions can be developed and applied to mitigate their risk. PMID:26694355

  2. Allostatic load and biological anthropology.

    PubMed

    Edes, Ashley N; Crews, Douglas E

    2017-01-01

    Multiple stressors affect developing and adult organisms, thereby partly structuring their phenotypes. Determining how stressors influence health, well-being, and longevity in human and nonhuman primate populations are major foci within biological anthropology. Although much effort has been devoted to examining responses to multiple environmental and sociocultural stressors, no holistic metric to measure stress-related physiological dysfunction has been widely applied within biological anthropology. Researchers from disciplines outside anthropology are using allostatic load indices (ALIs) to estimate such dysregulation and examine life-long outcomes of stressor exposures, including morbidity and mortality. Following allostasis theory, allostatic load represents accumulated physiological and somatic damage secondary to stressors and senescent processes experienced over the lifespan. ALIs estimate this wear-and-tear using a composite of biomarkers representing neuroendocrine, cardiovascular, metabolic, and immune systems. Across samples, ALIs are associated significantly with multiple individual characteristics (e.g., age, sex, education, DNA variation) of interest within biological anthropology. They also predict future outcomes, including aspects of life history variation (e.g., survival, lifespan), mental and physical health, morbidity and mortality, and likely health disparities between groups, by stressor exposures, ethnicity, occupations, and degree of departure from local indigenous life ways and integration into external and commodified ones. ALIs also may be applied to similar stress-related research areas among nonhuman primates. Given the reports from multiple research endeavors, here we propose ALIs may be useful for assessing stressors, stress responses, and stress-related dysfunction, current and long-term cognitive function, health and well-being, and risk of early mortality across many research programs within biological anthropology.

  3. Allostasis and allostatic load: implications for neuropsychopharmacology.

    PubMed

    McEwen, B S

    2000-02-01

    The primary hormonal mediators of the stress response, glucocorticoids and catecholamines, have both protective and damaging effects on the body. In the short run, they are essential for adaptation, maintenance of homeostasis, and survival (allostasis). Yet, over longer time intervals, they exact a cost (allostatic load) that can accelerate disease processes. The concepts of allostasis and allostatic load center around the brain as interpreter and responder to environmental challenges and as a target of those challenges. In anxiety disorders, depressive illness, hostile and aggressive states, substance abuse, and post-traumatic stress disorder (PTSD), allostatic load takes the form of chemical imbalances as well as perturbations in the diurnal rhythm, and, in some cases, atrophy of brain structures. In addition, growing evidence indicates that depressive illness and hostility are both associated with cardiovascular disease (CVD) and other systemic disorders. A major risk factor for these conditions is early childhood experiences of abuse and neglect that increase allostatic load later in life and lead individuals into social isolation, hostility, depression, and conditions like extreme obesity and CVD. Animal models support the notion of lifelong influences of early experience on stress hormone reactivity. Whereas, depression and childhood abuse and neglect tend to be more prevalent in individuals at the lower end of the socioeconomic ladder, cardiovascular and other diseases follow a gradient across the full range of socioeconomic status (SES). An SES gradient is also evident for measures of allostatic load. Wide-ranging SES gradients have also been described for substance abuse and affective and anxiety disorders as a function of education. These aspects are discussed as important, emerging public health issues where the brain plays a key role.

  4. Childhood Maltreatment Predicts Allostatic Load in Adulthood

    PubMed Central

    Widom, Cathy Spatz; Horan, Jacqueline; Brzustowicz, Linda

    2015-01-01

    Childhood maltreatment has been linked to numerous negative health outcomes. However, few studies have examined mediating processes using longitudinal designs or objectively measured biological data. This study sought to determine whether child abuse and neglect predicts allostatic load (a composite indicator of accumulated stress-induced biological risk) and to examine potential mediators. Using a prospective cohort design, children (ages 0-11) with documented cases of abuse and neglect were matched with non-maltreated children and followed up into adulthood with in-person interviews and a medical status exam (mean age 41). Allostatic load was assessed with nine physical health indicators. Child abuse and neglect predicted allostatic load, controlling for age, sex, and race. The direct effect of child abuse and neglect persisted despite the introduction of potential mediators of internalizing and externalizing problems in adolescence and social support and risky lifestyle in middle adulthood. These findings reveal the long-term impact of childhood abuse and neglect on physical health over 30 years later. PMID:25700779

  5. Childhood maltreatment predicts allostatic load in adulthood.

    PubMed

    Widom, Cathy Spatz; Horan, Jacqueline; Brzustowicz, Linda

    2015-09-01

    Childhood maltreatment has been linked to numerous negative health outcomes. However, few studies have examined mediating processes using longitudinal designs or objectively measured biological data. This study sought to determine whether child abuse and neglect predicts allostatic load (a composite indicator of accumulated stress-induced biological risk) and to examine potential mediators. Using a prospective cohort design, children (ages 0-11) with documented cases of abuse and neglect were matched with non-maltreated children and followed up into adulthood with in-person interviews and a medical status exam (mean age 41). Allostatic load was assessed with nine physical health indicators. Child abuse and neglect predicted allostatic load, controlling for age, sex, and race. The direct effect of child abuse and neglect persisted despite the introduction of potential mediators of internalizing and externalizing problems in adolescence and social support and risky lifestyle in middle adulthood. These findings reveal the long-term impact of childhood abuse and neglect on physical health over 30 years later.

  6. Allostatic load and reduced cortical thickness in schizophrenia.

    PubMed

    Chiappelli, Joshua; Kochunov, Peter; Savransky, Anya; Fisseha, Feven; Wisner, Krista; Du, Xiaoming; Rowland, Laura M; Hong, L Elliot

    2016-11-24

    Structural imaging studies have consistently found reduced gray matter thickness of the cerebral cortex in schizophrenia, a finding that is evident in first episode psychosis and may be progressive in some cases. Although genetic predisposition and medication effects may contribute to cortical thinning, we hypothesize that the cumulative effects of stress may represent an environmental factor impacting brain morphology in schizophrenia. We examined the relationship between allostatic load, an index of peripheral biomarkers representing the cumulative effects of stress, and cortical thickness. Allostatic load was calculated for 44 patients with schizophrenia spectrum disorders (SSD) and 33 normal controls (NC) based on 13 cardiovascular, neuroendocrine, immune, and metabolic measurements. Controlling for age, SSD had significantly elevated allostatic load as compared with NC (p=0.008). Controlling for age, whole brain average cortical thickness was lower in SSD patients compared to NC (p=0.008). However, once allostatic load was accounted for, the group difference in cortical thickness became marginal (p=0.058). Exploratory analyses on subcomponents of allostatic load suggested that elevated immune marker C-reactive protein, stress hormones, and cardiovascular indices within allostatic load were more strongly associated with reduced cortical thickness in SSD. In NC, only the association between immune marker C-reactive protein and cortical thickness was replicated. These results support the hypothesis that allostatic load may account for some of the gray matter deficits observed in schizophrenia. Among the allostatic indices, the inflammatory mechanism appears particularly relevant to cortical thickness in both schizophrenia patients and normal controls.

  7. The cost of chronic stress in childhood: understanding and applying the concept of allostatic load.

    PubMed

    Katz, Debra A; Sprang, Ginny; Cooke, Circe

    2012-09-01

    This article explores the concept of allostatic load and its utility as an integrative framework for thinking about the impact of chronic stress on children and adolescents. Allostatic load refers to the failure or exhaustion of normal physiologic processes that occurs in response to severe, frequent, or chronic stressors. This persistent physiologic dysregulation may lead to secondary health problems such as immunosuppression, obesity, atherosclerosis, and hypertension. Allostatic load can be measured and followed as a composite index of a group of physiologic parameters which fall outside of a normal range. Although research regarding allostatic load in children is limited, this article explores relevant studies and identifies ways in which the concept of allostatic load can be used to broaden approaches to assessment, case formulation, and treatment in children. The concept of allostatic load may be of particular interest to psychodynamic psychiatrists in recognizing the ways in which chronic stress and adverse childhood experiences lead not only to negative psychological sequelae but also to long-term health consequences including the possibility of premature death. It underscores the importance of monitoring patients' physical as well as psychological health and thinking about the complex interrelations between the two.

  8. Stress, Allostatic Load, Catecholamines, and Other Neurotransmitters in Neurodegenerative Diseases

    PubMed Central

    2017-01-01

    As populations age, the prevalence of geriatric neurodegenerative diseases will increase. These diseases generally are multifactorial, arising from complex interactions among genes, environment, concurrent morbidities, treatments, and time. This essay provides a concept for the pathogenesis of Lewy body diseases such as Parkinson disease, by considering them in the context of allostasis and allostatic load. Allostasis reflects active, adaptive processes that maintain apparent steady states, via multiple, interacting effectors regulated by homeostatic comparators—“homeostats.” Stress can be defined as a condition or state in which a sensed discrepancy between afferent information and a setpoint for response leads to activation of effectors, reducing the discrepancy. “Allostatic load” refers to the consequences of sustained or repeated activation of mediators of allostasis. From the analogy of an idling car, the revolutions per minute of the engine can be maintained at any of a variety of levels (allostatic states). Just as allostatic load (cumulative wear and tear) reflects design and manufacturing variations, byproducts of combustion, and time, eventually leading to engine breakdown, allostatic load in catecholaminergic neurons might eventually lead to Lewy body diseases. Central to the argument is that catecholaminergic neurons leak vesicular contents into the cytoplasm continuously during life and that catecholamines in the neuronal cytoplasm are autotoxic. These neurons therefore depend on vesicular sequestration to limit autotoxicity of cytosolic transmitter. Parkinson disease might be a disease of the elderly because of allostatic load, which depends on genetic predispositions, environmental exposures, repeated stress-related catecholamine release, and time. PMID:21615193

  9. Stress, Allostatic Load, Catecholamines, and Other Neurotransmitters in Neurodegenerative Diseases

    PubMed Central

    2016-01-01

    As populations age, the prevalence of geriatric neurodegenerative diseases will increase. These diseases generally are multifactorial, arising from complex interactions among genes, environment, concurrent morbidities, treatments, and time. This essay provides a concept for the pathogenesis of Lewy body diseases such as Parkinson disease, by considering them in the context of allostasis and allostatic load. Allostasis reflects active, adaptive processes that maintain apparent steady states, via multiple, interacting effectors regulated by homeostatic comparators—“homeostats.” Stress can be defined as a condition or state in which a sensed discrepancy between afferent information and a setpoint for response leads to activation of effectors, reducing the discrepancy. “Allostatic load” refers to the consequences of sustained or repeated activation of mediators of allostasis. From the analogy of an idling car, the revolutions per minute of the engine can be maintained at any of a variety of levels (allostatic states). Just as allostatic load (cumulative wear and tear) reflects design and manufacturing variations, byproducts of combustion, and time, eventually leading to engine breakdown, allostatic load in catecholaminergic neurons might eventually lead to Lewy body diseases. Central to the argument is that catecholaminergic neurons leak vesicular contents into the cytoplasm continuously during life and that catecholamines in the neuronal cytoplasm are autotoxic. These neurons therefore depend on vesicular sequestration to limit autotoxicity of cytosolic transmitter. Parkinson disease might be a disease of the elderly because of allostatic load, which depends on genetic predispositions, environmental exposures, repeated stress-related catecholamine release, and time. PMID:22297542

  10. Purpose in Life Predicts Allostatic Load Ten Years Later

    PubMed Central

    Zilioli, Samuele; Slatcher, Richard B.; Ong, Anthony D.; Gruenewald, Tara

    2015-01-01

    Objective Living a purposeful life is associated with better mental and physical health, including longevity. Accumulating evidence shows that these associations might be explained by the association between life purpose and regulation of physiological systems involved in the stress response. The aim of this study was to investigate the prospective associations between life purpose and allostatic load over a 10-year period. Methods Analyses were conducted using data from the Midlife in the United States (MIDUS) survey. Assessment of life purpose, psychological covariates and demographics were obtained at baseline, while biomarkers of allostatic load were assessed at the 10-year follow-up. Results We found that greater life purpose predicted lower levels of allostatic load at follow-up, even when controlling for other aspects of psychological well-being potentially associated with allostatic load. Further, life purpose was also a strong predictor of individual differences in self-health locus of control—i.e., beliefs about how much influence individuals can exert on their own health—which, in turn, partially mediated the association between purpose and allostatic load. Although life purpose was also negatively linked to other-health locus of control —i.e., the extent to which individuals believe their health is controlled by others/chance —this association did not mediate the impact of life purpose on allostatic load. Conclusion The current study provides the first empirical evidence for the long-term physiological correlates of life purpose and supports the hypothesis that self-health locus of control acts as one proximal psychological mechanism through which life purpose may be linked to positive biological outcomes. PMID:26526322

  11. Allostatic Load and Health Status of African Americans and Whites

    ERIC Educational Resources Information Center

    Deuster, Patricia A.; Kim-Dorner, Su Jong; Remaley, Alan T.; Poth, Merrily

    2011-01-01

    Objectives: To compare health risks in 84 healthy African American and 45 white men and women after calculating allostatic load (AL) from biologic, psychosocial, and behavioral measures. Methods: Participants (18-45 years) ranging in weight from normal to obese and without hypertension or diabetes. Fitness, body fat, CRP, mood, social support,…

  12. A Multimethodological Analysis of Cumulative Risk and Allostatic Load among Rural Children.

    ERIC Educational Resources Information Center

    Evans, Gary W.

    2003-01-01

    This study modeled physical and psychosocial aspects of home environment and personal characteristics in a cumulative risk heuristic. Found that elevated cumulative risk was associated with heightened cardiovascular and neuroendocrine parameters, increased deposition of body fat, and higher summary index of total allostatic load. Replicated…

  13. Measuring allostatic load in the workforce: a systematic review

    PubMed Central

    MAUSS, Daniel; LI, Jian; SCHMIDT, Burkhard; ANGERER, Peter; JARCZOK, Marc N.

    2014-01-01

    The Allostatic Load Index (ALI) has been used to establish associations between stress and health-related outcomes. This review summarizes the measurement and methodological challenges of allostatic load in occupational settings. Databases of Medline, PubPsych, and Cochrane were searched to systematically explore studies measuring ALI in working adults following the PRISMA statement. Study characteristics, biomarkers and methods were tabulated. Methodological quality was evaluated using a standardized checklist. Sixteen articles (2003–2013) met the inclusion criteria, with a total of 39 (range 6–17) different variables used to calculate ALI. Substantial heterogeneity was observed in the number and type of biomarkers used, the analytic techniques applied and study quality. Particularly, primary mediators were not regularly included in ALI calculation. Consensus on methods to measure ALI in working populations is limited. Research should include longitudinal studies using multi-systemic variables to measure employees at risk for biological wear and tear. PMID:25224337

  14. The role of education in explaining racial/ethnic allostatic load differentials in the United States.

    PubMed

    Howard, Jeffrey T; Sparks, P Johnelle

    2015-01-01

    This study expands on earlier findings of racial/ethnic and education-allostatic load associations by assessing whether racial/ethnic differences in allostatic load persist across all levels of educational attainment. This study used data from four recent waves of the National Health and Nutrition Survey (NHANES). Results from this study suggest that allostatic load differs significantly by race/ethnicity and educational attainment overall, but that the race/ethnicity association is not consistent across education level. Analysis of interactions and education-stratified models suggest that allostatic load levels do not differ by race/ethnicity for individuals with low education; rather, the largest allostatic load differentials for Mexican Americans (p < .01) and non-Hispanic blacks (p < .001) are observed for individuals with a college degree or more. These findings add to the growing evidence that differences in socioeconomic opportunities by race/ethnicity are likely a consequence of differential returns to education, which contribute to higher stress burdens among minorities compared to non-Hispanic whites.

  15. Allostatic load in parents of children with developmental disorders: moderating influence of positive affect.

    PubMed

    Song, Jieun; Mailick, Marsha R; Ryff, Carol D; Coe, Christopher L; Greenberg, Jan S; Hong, Jinkuk

    2014-02-01

    This study examines whether parents of children with developmental disorders are at risk of elevated allostatic load relative to control parents and whether positive affect moderates difference in risk. In all, 38 parents of children with developmental disorders and 38 matched comparison parents were analyzed. Regression analyses revealed a significant interaction between parent status and positive affect: parents of children with developmental disorders had lower allostatic load when they had higher positive affect, whereas no such association was evident for comparison parents. The findings suggest that promoting greater positive affect may lower health risks among parents of children with developmental disorders.

  16. Meeting physical activity guidelines is associated with lower allostatic load and inflammation in Mexican Americans.

    PubMed

    Gay, Jennifer L; Salinas, Jennifer J; Buchner, David M; Mirza, Shaper; Kohl, Harold W; Fisher-Hoch, Susan P; McCormick, Joseph B

    2015-04-01

    Examine the relationship between physical activity (PA) and allostatic load in Mexican-Americans as well as variations by gender. Self-reported PA as well as cardiovascular, metabolic and inflammatory markers were assessed in 330 Mexican-American adults in the Cameron County Hispanic Cohort (Brownsville, TX, USA). Dependent variables included total allostatic load, blood pressure, metabolic, and inflammatory scores. PA participation was categorized as sedentary, low, moderate, high, and by whether activity was sufficient to meet public health guidelines. Logistic regression analyses were conducted using cross-sectional data, and tested interaction effects of gender and PA. High active participants had lower allostatic load and inflammatory risk than sedentary participants. These relationships held for meeting versus not meeting guidelines. Males meeting guidelines were less likely to have high inflammation than other groups. The data did not suggest a dose-response association. These findings indicate that PA may reduce accumulation of allostatic load, highlighting the importance of a physically active lifestyle across the life span.

  17. Children's Negative Emotionality Combined with Poor Self-Regulation Affects Allostatic Load in Adolescence

    ERIC Educational Resources Information Center

    Dich, Nadya; Doan, Stacey; Evans, Gary

    2015-01-01

    The present study examined the concurrent and prospective, longitudinal effects of childhood negative emotionality and self-regulation on allostatic load (AL), a physiological indicator of chronic stress. We hypothesized that negative emotionality in combination with poor self-regulation would predict elevated AL. Mothers reported on children's…

  18. Perceived Discrimination among African American Adolescents and Allostatic Load: A Longitudinal Analysis with Buffering Effects

    ERIC Educational Resources Information Center

    Brody, Gene H.; Lei, Man-Kit; Chae, David H.; Yu, Tianyi; Kogan, Steven M.; Beach, Steven R. H.

    2014-01-01

    This study was designed to examine the prospective relations of perceived racial discrimination with allostatic load (AL), along with a possible buffer of the association. A sample of 331 African Americans in the rural South provided assessments of perceived discrimination from ages 16 to 18 years. When youth were 18 years, caregivers reported…

  19. Allostatic Load: Single Parents, Stress-Related Health Issues, and Social Care

    ERIC Educational Resources Information Center

    Johner, Randy L.

    2007-01-01

    This article explores the possible relationships between allostatic load (AL) and stress-related health issues in the low-income single-parent population, using both a population health perspective (PHP) and a biological framework. A PHP identifies associations among such factors as gender, income, employment, and social support and their…

  20. Impact of alprazolam in allostatic load and neurocognition of patients with anxiety disorders and chronic stress (GEMA): observational study protocol

    PubMed Central

    Soria, Carlos A; Remedi, Carolina; Núñez, Daniel A; D'Alessio, Luciana; Roldán, Emilio J A

    2015-01-01

    Introduction The allostatic load model explains the additive effects of multiple biological processes that accelerate pathophysiology related to stress, particularly in the central nervous system. Stress-related mental conditions such as anxiety disorders and neuroticism (a well-known stress vulnerability factor), have been linked to disturbances of hypothalamo–pituitary–adrenal with cognitive implications. Nevertheless, there are controversial results in the literature and there is a need to determine the impact of the psychopharmacological treatment on allostatic load parameters and in cognitive functions. Gador study of Estres Modulation by Alprazolam, aims to determine the impact of medication on neurobiochemical variables related to chronic stress, metabolic syndrome, neurocognition and quality of life in patients with anxiety, allostatic load and neuroticism. Methods/analysis In this observational prospective phase IV study, highly sympthomatic patients with anxiety disorders (six or more points in the Hamilton-A scale), neuroticism (more than 18 points in the Neo five personality factor inventory (NEO-FFI) scale), an allostatic load (three positive clinical or biochemical items at Crimmins and Seeman criteria) will be included. Clinical variables of anxiety, neuroticism, allostatic load, neurobiochemical studies, neurocognition and quality of life will be determined prior and periodically (1, 2, 4, 8, and 12 weeks) after treatment (on demand of alprazolam from 0.75 mg/day to 3.0 mg/day). A sample of n=55/182 patients will be considered enough to detect variables higher than 25% (pretreatment vs post-treatment or significant correlations) with a 1-ß power of 0–80. t Test and/or non-parametric test, and Pearson's test for correlation analysis will be determined. Ethics and dissemination This study protocol was approved by an Independent Ethics Committee of FEFyM (Foundation for Pharmacological Studies and Drugs, Buenos Aires) and by regulatory

  1. Allostatic Load Assessment for Early Detection of Stress in the Workplace in Egypt

    PubMed Central

    Ali, Ola Sayed; Badawy, Nadia; Rizk, Sanaa; Gomaa, Hend; Saleh, Mai Sabry

    2016-01-01

    AIM: Workplace stress is hazardous for its harmful impact on employees’ health and organizational productivity. The aim of the study is to apply the Allostatic Load Index (ALI) which is a multi-component measure for health risk assessment and early detection of stress among workers in Egypt. METHODS: Sixty-two working adults randomly selected from two different working environments in Egypt were included in the study. Participants completed a self-reported questionnaire for socio-demographic and work variables. Andrews and Withey test for Job Satisfaction was filled and 3 ml blood samples were collected. Markers assessed for Allostatic Load were serum cortisol, c-reactive protein, dehydroepiandrosterone-sulphate, total thyroxine, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, total cholesterol to high-density lipoprotein ratio, systolic and diastolic blood pressures, waist to hip ratio and body mass index. The risk quartile method was used for calculation of ALI. ALI value of four or more indicates high Allostatic Load. RESULTS: Job satisfaction scale defined about a quarter of the study population (24%) to be dissatisfied with Allostatic Load of 2.4 as the mean value. Population percentage with ALI ≥4 reached 12.9% with 100% of them females. A significant association was found between Allostatic Load of primary mediators and age, the presence of chronic diseases, place of work and female gender. CONCLUSION: Female gender and the old age of the Egyptian workforce under study are at higher risk of chronic diseases. Using an alternative way -for example, the cut-point method- instead of the risk quartiles for dichotomization of markers used in ALI calculation could be more precise for early detection of stress among healthy individuals. PMID:27703581

  2. Is there an independent association between burnout and increased allostatic load? Testing the contribution of psychological distress and depression.

    PubMed

    Hintsa, Taina; Elovainio, Marko; Jokela, Markus; Ahola, Kirsi; Virtanen, Marianna; Pirkola, Sami

    2016-08-01

    Burnout has been suggested to be related to depression. We examined the relationship between burnout and allostatic load, and whether this association is independent of psychological distress and depression. We measured burnout psychological distress, depression, and allostatic load in 3283 participants. Higher burnout (β = 0.06, p =0.003) and cynicism (β = 0.03, p = 0.031) and decreased professional efficacy (β = 0.03, p = 0.007) were related to higher allostatic load independent of age, sex, education, occupation and psychological distress. Depression, however, explained 60 percent of the association. Burnout is related to higher allostatic load, and this association partly overlaps with co-occurring depression.

  3. From Childhood Maltreatment to Allostatic Load in Adulthood: The Role of Social Support.

    PubMed

    Horan, Jacqueline M; Widom, Cathy S

    2015-11-01

    Although previous research has documented that social support acts as a protective factor for individuals exposed to trauma, most research relies on assessments of social support at one point in time. The present study used data from a prospective cohort design study to examine the stability of social support from childhood through middle adulthood in individuals with documented histories of childhood abuse and neglect and matched controls (aged 0-11) and assessed the impact of social support on allostatic load, a composite measure of physiological stress response assessed through blood tests and physical measurements, in middle adulthood. Maltreated children are more likely to have unstable social support across the life span, compared to matched controls. Social support across the life span partially mediated the relationship between child maltreatment and allostatic load in adulthood, although there were differences by race and sex. These findings have implications for interventions to prevent the negative consequences of child maltreatment.

  4. Child maltreatment and allostatic load: consequences for physical and mental health in children from low-income families.

    PubMed

    Rogosch, Fred A; Dackis, Melissa N; Cicchetti, Dante

    2011-11-01

    Child maltreatment and biomarkers of allostatic load were investigated in relation to child health problems and psychological symptomatology. Participants attended a summer research day camp and included 137 maltreated and 110 nonmaltreated low-income children, who were aged 8 to 10 years (M = 9.42) and racially and ethnically diverse; 52% were male. Measurements obtained included salivary cortisol and dehydroepiandosterone, body mass index, waist-hip ratio, and blood pressure; these indicators provided a composite index of allostatic load. Child self-report and camp adult-rater reports of child symptomatology were obtained; mothers provided information on health problems. The results indicated that higher allostatic load and child maltreatment status independently predicted poorer health outcomes and greater behavior problems. Moderation effects indicated that allostatic load was related to somatic complaints, attention problems, and thought problems only among maltreated children. Risks associated with high waist-hip ratio, low morning cortisol, and high morning dehydroepiandosterone also were related to depressive symptoms only for maltreated children. The results support an allostatic load conceptualization of the impact of high environmental stress and child abuse and neglect on child health and behavioral outcomes and have important implications for long-term physical and mental health.

  5. Child Maltreatment and Allostatic Load: Consequences for Physical and Mental Health in Children from Low-Income Families

    PubMed Central

    Rogosch, Fred A.; Dackis, Melissa N.; Cicchetti, Dante

    2012-01-01

    Child maltreatment and biomarkers of allostatic load were investigated in relation to child health problems and psychological symptomatology. Participants attended a summer research day camp and included 137 maltreated and 110 nonmaltreated low-income children, who were aged 8 to 10 years (M = 9.42) and racially and ethnically diverse; 52% were male. Measurements obtained included salivary cortisol and DHEA, body-mass index, waist-hip ratio, and blood pressure; these indicators provided a composite index of allostatic load. Child self-report and camp adult-rater reports of child symptomatology were obtained; mothers provided information on health problems. The results indicated that higher allostatic load and child maltreatment status independently predicted poorer health outcomes and greater behavior problems. Moderation effects indicated that allostatic load was related to somatic complaints, attention problems, and thought problems only among maltreated children. Risks associated with high waist-hip ratio, low morning cortisol, and high morning DHEA also were related to depressive symptoms only for maltreated children. The results support an allostatic load conceptualization of the impact of high environmental stress and child abuse and neglect on child health and behavioral outcomes and have important implications for long-term physical and mental health. PMID:22018084

  6. Allostatic load is associated with chronic conditions in the Boston Puerto Rican Health Study

    PubMed Central

    Mattei, Josiemer; Demissie, Serkalem; Falcon, Luis M; Ordovas, Jose M

    2010-01-01

    Puerto Ricans living in the United States mainland present multiple disparities in prevalence of chronic diseases, relative to other racial and ethnic groups. Allostatic load (AL), or the cumulative wear and tear of physiological responses to stressors such as major life events, social and environmental burden, has been proposed as a possible mechanism for the inequalities observed in minority groups, but has not been studied in Puerto Ricans. The aim of this study was to determine the association of AL to six chronic diseases (abdominal obesity, hypertension, diabetes, and self-reported cardiovascular disease (CVD), arthritis and cancer) in Puerto Ricans, and to contrast AL to metabolic syndrome (MetS). Participants of the Boston Puerto Rican Health Study (n=1,116, ages 45–75 years) underwent a home-based interview, where questionnaires were completed and biological samples collected. A summary definition of AL was constructed using clinically-defined cutoffs and medication use for 10 physiological parameters in different body systems. Logistic regression models were run to determine associations between AL score and disease status, controlling for age, sex, smoking, alcohol use, physical activity, total fat intake and energy intake. Parallel models were also run with MetS score replacing AL. We found that increasing categories of AL score were significantly associated with abdominal obesity, hypertension, diabetes and self-reported cardiovascular disease (CVD) and arthritis, but not with self-reported cancer. The strength of associations of AL with all conditions, except diabetes and cancer, was similar to or larger than those of MetS score. In conclusion, Puerto Rican older adults experienced physiological dysregulation that was associated with increased odds of chronic conditions. AL was more strongly associated with most conditions, compared to MetS, suggesting that this cumulative measure may be a better predictor of disease. These results have prospective

  7. A streamlined approach for assessing the Allostatic Load Index in industrial employees.

    PubMed

    Mauss, Daniel; Jarczok, Marc N; Fischer, Joachim E

    2015-01-01

    Work stress is common and can lead to various bodily dysfunctions. The Allostatic Load Index (ALI) is a tool to measure the wear and tear of the body caused by chronic stress. This cross-sectional study aimed to explore the association of work-related stress and ALI in German industrial employees. A short form ALI should be developed for practical use of company physicians. In this exploration of an industrial cohort (n = 3797; 79.3% male), work stress was measured by the effort-reward imbalance (ERI) questionnaire in 2009-2011. ALI was calculated using 15 variables including anthropometric data, heart rate variability, as well as blood and urine samples based on predefined subclinical cut-off values. Differences in ALI related to low (≤1) and high (>1) ERI categories were tested. Logistic regression models estimated odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for the association between ALI and work stress controlling for multiple confounders. Employees exposed to high work stress showed higher ALI scores (p < 0.001) compared to those with low stress levels. In multivariable models, ALI was associated with work stress (OR 1.19 [95% CI: 1.00, 1.42]; p < 0.05) following adjustment for a range of potential confounders. By reducing ALI parameters to five variables this association increased modestly and remained statistically significant (OR 1.27 [95% CI: 1.05, 1.54]; p < 0.05). The results indicate that work stress is associated with ALI in German industrial employees. A short form index seems to be a promising approach for occupational health practitioners. The results should be validated in further longitudinal explorations defining a standard set of variables including gender-related thresholds.

  8. Interparental Aggression and Children’s Adrenocortical Reactivity: Testing an Evolutionary Model of Allostatic Load

    PubMed Central

    Davies, Patrick T.; Sturge-Apple, Melissa L.; Cicchetti, Dante

    2011-01-01

    Guided by an evolutionary model of allostatic load (Korte, Koolhaas, Wingfield, & McEwen, 2005), this study examined the hypothesis that the association between interparental aggression and subsequent changes in children’s cortisol reactivity to interparental conflict is moderated by their temperamental dispositions. Participants of the multi-method, longitudinal study included 201 two-year-old toddlers and their mothers. These children experienced elevated levels of aggression between parents. Consistent with the theory, the results indicated that interparental aggression predicted greater cortisol reactivity over a one year period for children who exhibited high levels of temperamental inhibition and vigilance. Conversely, for children with bold, aggressive temperamental characteristics, interparental aggression was marginally associated with diminished cortisol reactivity. Further underscoring its implications for allostatic load, increasing cortisol reactivity over the one year span was related to concomitant increases in internalizing symptoms but decreases in attention and hyperactivity difficulties. In supporting the evolutionary conceptualization, these results further supported the relative developmental advantages and costs associated with escalating and dampened cortisol reactivity to interparental conflict. PMID:21756433

  9. A developmental increase in allostatic load from ages 3 to 11 years is associated with increased schizotypal personality at age 23 years.

    PubMed

    Peskin, Melissa; Raine, Adrian; Gao, Yu; Venables, Peter H; Mednick, Sarnoff A

    2011-11-01

    Although allostatic load has been investigated in mood and anxiety disorders, no prior study has investigated developmental change in allostatic load as a precursor to schizotypal personality. This study employed a multilevel developmental framework to examine whether the development of increased allostatic load, as indicated by impaired sympathetic nervous system habituation from ages 3 to 11 years, predisposes to schizotypal personality at age 23 years. Electrodermal activity to six aversive tones was recorded in 995 subjects at age 3 years and again at 11 years. Habituation slopes at both ages were used to create groups who showed a developmental increase in habituation (decreased allostatic load), and those who showed a developmental decrease in habituation (increased allostatic load). Children who showed a developmental increase in allostatic load from ages 3 to 11 years had higher levels of schizotypal personality at 23 years. A breakdown of total schizotypy scores demonstrated specificity of findings to cognitive-perceptual features of schizotypy. Findings are the first to document a developmental abnormality in allostasis in relation to adult schizotypal personality. The relative failure to develop normal habituation to repeated stressors throughout childhood is hypothesized to result in an accumulation of allostatic load and consequently increased positive symptom schizotypy in adulthood.

  10. Stress, Place, and Allostatic Load Among Mexican Immigrant Farmworkers in Oregon.

    PubMed

    McClure, Heather H; Josh Snodgrass, J; Martinez, Charles R; Squires, Erica C; Jiménez, Roberto A; Isiordia, Laura E; Eddy, J Mark; McDade, Thomas W; Small, Jeon

    2015-10-01

    Cumulative exposure to chronic stressors has been shown to contribute to immigrants' deteriorating health with more time in US residence. Few studies, however, have examined links among common psychosocial stressors for immigrants (e.g., acculturation-related) and contexts of immigrant settlement for physical health. The study investigated relationships among social stressors, stress buffers (e.g., family support), and allostatic load (AL)--a summary measure of physiological "wear and tear"--among 126 adult Mexican immigrant farm workers. Analyses examined social contributors to AL in two locales: (1) White, English-speaking majority sites, and (2) a Mexican immigrant enclave. Our six-point AL scale incorporated immune, cardiovascular, and metabolic measures. Among men and women, older age predicted higher AL. Among women, lower family support related to higher AL in White majority communities only. Findings suggest that Latino immigrants' cumulative experiences in the US significantly compromise their health, with important differences by community context.

  11. Perceived Discrimination among African American Adolescents and Allostatic Load: A Longitudinal Analysis with Buffering Effects

    PubMed Central

    Brody, Gene H.; Lei, Man-Kit; Chae, David H.; Yu, Tianyi; Kogan, Steven M.; Beach, Steven R. H.

    2013-01-01

    This study was designed to examine the prospective relations of perceived racial discrimination with allostatic load (AL), along with a possible buffer of the association. A sample of 331 African Americans in the rural South provided assessments of perceived discrimination from ages 16 to 18 years. When youths were 18, caregivers reported parental emotional support, and youths assessed peer emotional support. AL and potential confounder variables were assessed when youths were 20. Latent Growth Mixture Modeling identified two perceived discrimination classes: high and stable and low and increasing. Adolescents in the high and stable class evinced heightened AL even with confounder variables controlled. The racial discrimination to AL link was not significant for young adults who received high emotional support. PMID:24673162

  12. Allostatic Load as a Complex Clinical Construct: A Case-Based Computational Modeling Approach.

    PubMed

    Buckwalter, J Galen; Castellani, Brian; McEwen, Bruce; Karlamangla, Arun S; Rizzo, Albert A; John, Bruce; O'Donnell, Kyle; Seeman, Teresa

    2016-01-01

    Allostatic load (AL) is a complex clinical construct, providing a unique window into the cumulative impact of stress. However, due to its inherent complexity, AL presents two major measurement challenges to conventional statistical modeling (the field's dominant methodology): it is comprised of a complex causal network of bioallostatic systems, represented by an even larger set of dynamic biomarkers; and, it is situated within a web of antecedent socioecological systems, linking AL to differences in health outcomes and disparities. To address these challenges, we employed case-based computational modeling (CBM), which allowed us to make four advances: (1) we developed a multisystem, 7-factor (20 biomarker) model of AL's network of allostatic systems; (2) used it to create a catalog of nine different clinical AL profiles (causal pathways); (3) linked each clinical profile to a typology of 23 health outcomes; and (4) explored our results (post hoc) as a function of gender, a key socioecological factor. In terms of highlights, (a) the Healthy clinical profile had few health risks; (b) the pro-inflammatory profile linked to high blood pressure and diabetes; (c) Low Stress Hormones linked to heart disease, TIA/Stroke, diabetes, and circulation problems; and (d) high stress hormones linked to heart disease and high blood pressure. Post hoc analyses also found that males were overrepresented on the High Blood Pressure (61.2%), Metabolic Syndrome (63.2%), High Stress Hormones (66.4%), and High Blood Sugar (57.1%); while females were overrepresented on the Healthy (81.9%), Low Stress Hormones (66.3%), and Low Stress Antagonists (stress buffers) (95.4%) profiles.

  13. Allostatic Load in Foreign-Born and US-Born Blacks: Evidence From the 2001–2010 National Health and Nutrition Examination Survey

    PubMed Central

    Dinwiddie, Gniesha Y.

    2015-01-01

    Objectives. We tested whether the immigrant health advantage applies to non-Hispanic Black immigrants and examined whether nativity-based differences in allostatic load exist among non-Hispanic Blacks. Methods. We used pooled data from the 2001–2010 National Health and Nutrition Examination Survey to compare allostatic load scores for US-born (n = 2745) and foreign-born (n = 152) Black adults. We used multivariate logistic regression techniques to assess the association between nativity and high allostatic load scores, controlling for gender, age, health behaviors, and socioeconomic status. Results. For foreign-born Blacks, length of stay and age were powerful predictors of allostatic load scores. For older US-born Blacks and those who were widowed, divorced, or separated, the risk of high allostatic load was greater. Conclusions. Foreign-born Blacks have a health advantage in allostatic load. Further research is needed that underscores a deeper understanding of the mechanisms driving this health differential to create programs that target these populations differently. PMID:25602865

  14. Life Events Trajectories, Allostatic Load, and the Moderating Role of Age at Arrival from Puerto Rico to the US Mainland

    PubMed Central

    Arévalo, Sandra P.; Tucker, Katherine L; Falcon, Luis M

    2014-01-01

    Our aim was to examine the effects of trajectories of stressful life events on allostatic load, measured over a two year time period, and to investigate the roles of language acculturation and age at migration in this association, in a sample of Puerto Rican migrants. We used data from the Boston Puerto Rican Health Study; a population-based prospective cohort of older Puerto Ricans recruited between the ages of 45 and 75 years. The Institutional Review Boards at Tufts Medical Center and Northeastern University approved the study. We used latent growth mixture modeling (LGMM) to identify different classes of two-year trajectories of stressful life events; analysis of variance to examine group differences by stress trajectory; and linear regression to test for the modifying effects of age at arrival on the association of stress trajectory with allostatic load at follow-up. In LGMM analysis, we identified three distinct stress trajectories; low, moderate ascending, and high. Unexpectedly, participants in the low stress group had the highest allostatic load at follow-up (F=4.4, p=0.01) relative to the other two groups. Age at arrival had a statistically significant moderating effect on the association. A reported two year period of moderate but repetitive and increasingly bad life events was associated with increases in allostatic load for participants who arrived to the U.S. mainland after the age of 5 years, and was particularly strong for those arriving between 6–11 years, but not for those arriving earlier or later. Results from this study highlight the complex effects of stress during the life course, and point to certain vulnerable periods for immigrant children that could modify long term effects of stress. PMID:25265208

  15. Shorter telomeres with high telomerase activity are associated with raised allostatic load and impoverished psychosocial resources.

    PubMed

    Zalli, Argita; Carvalho, Livia A; Lin, Jue; Hamer, Mark; Erusalimsky, Jorge D; Blackburn, Elizabeth H; Steptoe, Andrew

    2014-03-25

    Recent work has linked psychological stress with premature cellular aging as indexed by reduced leukocyte telomere length. The combination of shorter telomeres with high telomerase activity (TA) may be indicative of active cell stress. We hypothesized that older individuals characterized by shorter telomeres with high TA in unstimulated leukocytes would show signs of high allostatic load and low levels of protective psychosocial resources. We studied 333 healthy men and women aged 54-76 y who underwent laboratory testing in which we measured cardiovascular, neuroendocrine, and inflammatory responses to standardized mental stress tasks. The tasks elicited prompt increases in blood pressure (BP), heart rate, cortisol, and mediators of inflammation and reductions in heart rate variability, returning toward baseline levels following stress. However, men having shorter telomeres with high TA showed blunted poststress recovery in systolic BP, heart rate variability, and monocyte chemoattractant protein-1, together with reduced responsivity in diastolic BP, heart rate, and cortisol, in comparison to men with longer telomeres or men with shorter telomeres and low TA. Shorter telomeres with high TA were also associated with reduced social support, lower optimism, higher hostility, and greater early life adversity. These effects were independent of age, socioeconomic status, and body mass index. We did not observe differences among older women. Our findings suggest that active cell stress is associated with impaired physiological stress responses and impoverished psychosocial resources, reflecting an integration of cellular, systemic, and psychological stress processes potentially relevant to health in older men.

  16. Mismatch or allostatic load? Timing of life adversity differentially shapes gray matter volume and anxious temperament.

    PubMed

    Kuhn, Manuel; Scharfenort, Robert; Schümann, Dirk; Schiele, Miriam A; Münsterkötter, Anna L; Deckert, Jürgen; Domschke, Katharina; Haaker, Jan; Kalisch, Raffael; Pauli, Paul; Reif, Andreas; Romanos, Marcel; Zwanzger, Peter; Lonsdorf, Tina B

    2016-04-01

    Traditionally, adversity was defined as the accumulation of environmental events (allostatic load). Recently however, a mismatch between the early and the later (adult) environment (mismatch) has been hypothesized to be critical for disease development, a hypothesis that has not yet been tested explicitly in humans. We explored the impact of timing of life adversity (childhood and past year) on anxiety and depression levels (N = 833) and brain morphology (N = 129). Both remote (childhood) and proximal (recent) adversities were differentially mirrored in morphometric changes in areas critically involved in emotional processing (i.e. amygdala/hippocampus, dorsal anterior cingulate cortex, respectively). The effect of adversity on affect acted in an additive way with no evidence for interactions (mismatch). Structural equation modeling demonstrated a direct effect of adversity on morphometric estimates and anxiety/depression without evidence of brain morphology functioning as a mediator. Our results highlight that adversity manifests as pronounced changes in brain morphometric and affective temperament even though these seem to represent distinct mechanistic pathways. A major goal of future studies should be to define critical time periods for the impact of adversity and strategies for intervening to prevent or reverse the effects of adverse childhood life experiences.

  17. Mismatch or allostatic load? Timing of life adversity differentially shapes gray matter volume and anxious temperament

    PubMed Central

    Kuhn, Manuel; Scharfenort, Robert; Schümann, Dirk; Schiele, Miriam A.; Münsterkötter, Anna L.; Deckert, Jürgen; Domschke, Katharina; Haaker, Jan; Kalisch, Raffael; Pauli, Paul; Reif, Andreas; Romanos, Marcel; Zwanzger, Peter

    2016-01-01

    Traditionally, adversity was defined as the accumulation of environmental events (allostatic load). Recently however, a mismatch between the early and the later (adult) environment (mismatch) has been hypothesized to be critical for disease development, a hypothesis that has not yet been tested explicitly in humans. We explored the impact of timing of life adversity (childhood and past year) on anxiety and depression levels (N = 833) and brain morphology (N = 129). Both remote (childhood) and proximal (recent) adversities were differentially mirrored in morphometric changes in areas critically involved in emotional processing (i.e. amygdala/hippocampus, dorsal anterior cingulate cortex, respectively). The effect of adversity on affect acted in an additive way with no evidence for interactions (mismatch). Structural equation modeling demonstrated a direct effect of adversity on morphometric estimates and anxiety/depression without evidence of brain morphology functioning as a mediator. Our results highlight that adversity manifests as pronounced changes in brain morphometric and affective temperament even though these seem to represent distinct mechanistic pathways. A major goal of future studies should be to define critical time periods for the impact of adversity and strategies for intervening to prevent or reverse the effects of adverse childhood life experiences. PMID:26568620

  18. Cumulative neighborhood risk of psychosocial stress and allostatic load in adolescents.

    PubMed

    Theall, Katherine P; Drury, Stacy S; Shirtcliff, Elizabeth A

    2012-10-01

    The authors examined the impact of cumulative neighborhood risk of psychosocial stress on allostatic load (AL) among adolescents as a mechanism through which life stress, including neighborhood conditions, may affect health and health inequities. They conducted multilevel analyses, weighted for sampling and propensity score-matched, among adolescents aged 12-20 years in the National Health and Nutrition Examination Survey (1999-2006). Individuals (first level, n = 11,886) were nested within families/households (second level, n = 6,696) and then census tracts (third level, n = 2,191) for examination of the contextual effect of cumulative neighborhood risk environment on AL. Approximately 35% of adolescents had 2 or more biomarkers of AL. A significant amount of variance in AL was explained at the neighborhood level. The likelihood of having a high AL was approximately 10% higher for adolescents living in medium-cumulative-risk neighborhoods (adjusted odds ratio (OR) = 1.09, 95% confidence interval (CI): 1.08, 1.09), 28% higher for those living in high-risk neighborhoods (adjusted OR = 1.28, 95% CI: 1.27, 1.30), and 69% higher for those living in very-high-risk neighborhoods (adjusted OR = 1.69, 95% CI: 1.68, 1.70) as compared with adolescents living in low-risk areas. Effect modification was observed by both individual- and neighborhood-level sociodemographic factors. These findings offer support for the hypothesis that neighborhood risks may culminate in a range of biologically mediated negative health outcomes detectable in adolescents.

  19. Rearing history and allostatic load in adult western lowland gorillas (Gorilla gorilla gorilla) in human care.

    PubMed

    Edes, Ashley N; Wolfe, Barbara A; Crews, Douglas E

    2016-01-01

    Disrupted rearing history is a psychological and physical stressor for nonhuman primates, potentially resulting in multiple behavioral and physiological changes. As a chronic, soma-wide stressor, altered rearing may be best assessed using a holistic tool such as allostatic load (AL). In humans, AL estimates outcomes of lifetime stress-induced damage. We predicted mother-reared gorillas would have lower AL than nursery-reared and wild-caught conspecifics. We estimated AL for 27 gorillas housed at the Columbus Zoo and Aquarium between 1956 and 2014. AL estimates were calculated using biomarkers obtained during previous anesthetic events. Biomarkers in the high-risk quartile were counted toward a gorilla's AL. Rearing history was categorized as mother-reared, nursery-reared, and wild-caught. Using ANCOVA, rearing history and AL are significantly associated when age and sex are entered as covariates. Wild-caught gorillas have significantly higher AL than mother-reared gorillas. Neither wild-caught nor mother-reared gorillas are significantly different from nursery-reared gorillas. When examined by sex, males of all rearing histories have significantly lower AL than females. We suggest males face few stressors in human care and ill effects of rearing history do not follow. Wild-caught females have significantly higher AL than mother-reared females, but neither is significantly different from nursery-reared females. Combined with our previous work on AL in this group, wherein females had twofold higher AL than males, we suggest females in human care face more stressors than males. Disrupted rearing history may exacerbate effects of these stressors. Providing opportunities for females to choose their distance from males may help reduce their AL.

  20. Work Stress, Caregiving and Allostatic Load: Prospective results from Whitehall II cohort study

    PubMed Central

    Dich, Nadya; Lange, Theis; Head, Jenny; Rod, Naja Hulvej

    2015-01-01

    Objective Studies investigating health effects of work and family stress usually consider these factors in isolation. The present study investigated prospective interactive effects of job strain and informal caregiving on allostatic load (AL), a multisystem indicator of physiological dysregulation. Methods Subjects were 7,007 British civil servants from the Whitehall II cohort study. Phase 3 (1991-1994) served as the baseline, Phases 5 (1997-1999) and 7 (2002-2004) as follow-ups. Job strain (high job demands combined with low control) and caregiving (providing care to aged or disabled relatives) were assessed at baseline. AL index (possible range 0-9) was assessed at baseline and both follow-ups based on 9 cardiovascular, metabolic and immune biomarkers. Linear mixed effect models were used to examine the association of job strain and caregiving with AL. Results High caregiving burden (above the sample median weekly hours of providing care) predicted higher AL levels, with the effect strongest in those also reporting job strain [b = 0.36, 95% CI: 0.01– 0.71)]; however, the interaction between job strain and caregiving was not significant (p = 0.56). Regardless of job strain, participants with low caregiving burden (below sample median) had lower subsequent AL levels than non-caregivers [b = 0.22, 95% CI: 0.06–0.37]. Conclusions The study provides some evidence for adverse effects of stress at work combined with family demands on physiological functioning. However, providing care to others may also have health protective effects if it does not involve excessive time commitment. PMID:25984826

  1. Marital Conflict, Allostatic Load, and the Development of Children's Fluid Cognitive Performance

    ERIC Educational Resources Information Center

    Hinnant, J. Benjamin; El-Sheikh, Mona; Keiley, Margaret; Buckhalt, Joseph A.

    2013-01-01

    Relations between marital conflict, children's respiratory sinus arrhythmia (RSA), and fluid cognitive performance were examined over 3 years to assess allostatic processes. Participants were 251 children reporting on marital conflict, baseline RSA, and RSA reactivity (RSA-R) to a lab challenge were recorded, and fluid cognitive performance…

  2. Views of a good life and allostatic load: Physiological correlates of theories of a good life depend on the socioeconomic context.

    PubMed

    Levine, Cynthia S; Atkins, Alexandra Halleen; Waldfogel, Hannah Benner; Chen, Edith

    2016-01-01

    This research examines the relationship between one's theory of a good life and allostatic load, a marker of cumulative biological risk, and how this relationship differs by socioeconomic status. Among adults with a bachelor's degree or higher, those who saw individual characteristics (e.g., personal happiness, effort) as part of a good life had lower levels of allostatic load than those who did not. In contrast, among adults with less than a bachelor's degree, those who saw supportive relationships as part of a good life had lower levels of allostatic load than those who did not. These findings extend past research on socioeconomic differences in the emphasis individual or relational factors and suggest that one's theory of a good life has health implications.

  3. “Weathering” and Age Patterns of Allostatic Load Scores Among Blacks and Whites in the United States

    PubMed Central

    Geronimus, Arline T.; Hicken, Margaret; Keene, Danya; Bound, John

    2006-01-01

    Objectives. We considered whether US Blacks experience early health deterioration, as measured across biological indicators of repeated exposure and adaptation to stressors. Methods. Using National Health and Nutrition Examination Survey data, we examined allostatic load scores for adults aged 18–64 years. We estimated probability of a high score by age, race, gender, and poverty status and Blacks’ odds of having a high score relative to Whites’ odds. Results. Blacks had higher scores than did Whites and had a greater probability of a high score at all ages, particularly at 35–64 years. Racial differences were not explained by poverty. Poor and nonpoor Black women had the highest and second highest probability of high allostatic load scores, respectively, and the highest excess scores compared with their male or White counterparts. Conclusions. We found evidence that racial inequalities in health exist across a range of biological systems among adults and are not explained by racial differences in poverty. The weathering effects of living in a race-conscious society may be greatest among those Blacks most likely to engage in high-effort coping. PMID:16380565

  4. Growth Delay as an Index of Allostatic Load in Young Children: Predictions to Disinhibited Social Approach and Diurnal Cortisol Activity

    PubMed Central

    Johnson, Anna E.; Bruce, Jacqueline; Tarullo, Amanda R.; Gunnar, Megan R.

    2012-01-01

    The goal of this study was to examine whether growth delay can serve as an index of allostatic load during early development, as it is well known that the activity of stress-mediating systems inhibits growth. The participants were children adopted internationally from institutional care (n = 36), children adopted internationally from foster care (n = 6), and nonadopted children (n = 35). For the adopted children, height-for-age and weight-for-height were assessed at adoption; for all children, disinhibited social approach (DSA; termed elsewhere as “indiscriminate friendliness”) and diurnal cortisol were assessed at 6–8 years (M = 6.9 years). For internationally adopted children in general, and postinstitutionalized children specifically, linear growth delay assessed at the time of adoption was associated with more dysregulated behavior in response to an unfamiliar adult (i.e., greater DSA) and a more dysregulated diurnal cortisol rhythm (i.e., higher late-afternoon and evening values). Further, among the most growth-delayed children, higher cortisol levels later in the day were correlated with DSA. The potential for using growth delay as an allostatic load indicator and the possible problems and limitations in its use in child populations are discussed. PMID:21756437

  5. The APOA1/C3/A4/A5 cluster and markers of allostatic load in the Boston Puerto Rican Health Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The APOA1/C3/A4/A5 cluster encodes key regulators of plasma lipids. Interactions between dietary factors and single nucleotide polymorphisms (SNPs) in the cluster have been reported. Allostatic load, or physiological dysregulation in response to stress, has been implicated in shaping health disparit...

  6. Sex-specific interaction effects of age, occupational status, and workplace stress on psychiatric symptoms and allostatic load among healthy Montreal workers.

    PubMed

    Juster, Robert-Paul; Moskowitz, D S; Lavoie, Joel; D'Antono, Bianca

    2013-11-01

    Socio-demographics and workplace stress may affect men and women differently. The aim of this cross-sectional study was to assess sex-specific interactions among age, occupational status, and workplace Demand-Control-Support (D-C-S) factors in relation to psychiatric symptoms and allostatic load levels representing multi-systemic "wear and tear". It was hypothesized that beyond main effects, D-C-S factors would be moderated by occupational status and age in sex-specific directions predictive of subjective psychiatric symptoms and objective physiological dysregulations. Participants included healthy male (n = 81) and female (n = 118) Montreal workers aged 20 to 64 years (Men: M = 39.4 years, SD = 11.3; Women: M = 42.8 years, SD = 11.38). The Job Content Questionnaire was administered to assess workplace D-C-S factors that included psychological demands, decisional latitude, and social support. Occupational status was coded using the Nam--Powers--Boyd system derived from the Canadian census. Psychiatric symptoms were assessed using the Beck Anxiety Scale and the Beck Depression Inventory II. Sex-specific allostatic load indices were calculated based on fifteen biomarkers. Regression analyses revealed that higher social support was associated with less depressive symptoms in middle aged (p = 0.033) and older men (p = 0.027). Higher occupational status was associated with higher allostatic load levels for men (p = 0.035), while the reverse occurred for women (p = 0.048). Women with lower occupational status but with higher decision latitude had lower allostatic load levels, as did middle-aged (p = 0.031) and older women (p = 0.003) with higher psychological demands. In summary, age and occupational status moderated workplace stress in sex-specific ways that have occupational health implications.

  7. Neighborhood socioeconomic context and change in allostatic load among older Puerto Ricans: The Boston Puerto Rican health study.

    PubMed

    Jiménez, Marcia P; Osypuk, Theresa L; Arevalo, Sandra; Tucker, Katherine L; Falcon, Luis M

    2015-05-01

    Neighborhood context may influence health and health disparities. However, most studies have been constrained by cross-sectional designs that limit causal inference due to failing to establish temporal order of exposure and disease. We tested the impact of baseline neighborhood context (neighborhood socioeconomic status factor at the block-group level, and relative income of individuals compared to their neighbors) on allostatic load two years later. We leveraged data from the Boston Puerto Rican Health Study, a prospective cohort of aging Puerto Rican adults (aged 45-75 at baseline), with change in AL modeled between baseline and the 2nd wave of follow-up using two-level hierarchical linear regression models. Puerto Rican adults with higher income, relative to their neighbors, exhibited lower AL after two years, after adjusting for NSES, age, gender, individual-level SES, length of residence, and city. After additional control for baseline AL, this association was attenuated to marginal significance. We found no significant association of NSES with AL. Longitudinal designs are an important tool to understand how neighborhood contexts influence health and health disparities.

  8. Exploring the bio-behavioural link between stress, allostatic load & micronutrient status: A cross-sectional study among adolescent boys

    PubMed Central

    Augustine, Little Flower; Nair, Krishnapillai Madhavan; Rao, Sylvia Fernandez; Rao, Mendu Vishnu Vardhana; Ravinder, Punjal; Laxmaiah, Avula

    2016-01-01

    Background & objectives: Allostatic load (AL) is a cumulative measure of physiological deregulation and is influenced by multiple factors including nutrition. The objectives of the study were to assess AL among adolescent boys (15-19 yr) and delineate its association with psychological stress and micronutrient status. Methods: A cross-sectional, school-based study was conducted among 370 adolescent boys of five higher secondary schools from Hyderabad, India. Perceived stress, adolescent life event stress (ALES), psychological morbidity and coping were measured. Biomarkers of AL included dehydroepiandrosterone sulphate, 12-h urinary cortisol, interleukin-6, C-reactive protein, lipid profile, body mass index and blood pressure. Micronutrient status with respect to iron (haemoglobin, ferritin, hepcidin, soluble transferrin receptor), folate, vitamins B12, C and A were analyzed in a sub-sample of 146 boys. AL score ≥3 was calculated from eight biomarkers. Results: Fourteen per cent participants had no AL but 34.3 per cent had AL score of ≥ 3. Unadjusted means of ALES scores were significantly different (P = 0.045) among participants with low [mean, 95% confidence interval (CI): 580, 531-629] and high (663, 605-721) AL. After controlling for confounders, the means were significantly different for controllable life event sub-scale of ALES (P = 0.048). Adjusted hepcidin concentrations were significantly higher among participants with high AL (means, 95% CI, 27.2, 24.0-30.8 for high AL; 22.1, 20.2-24.2 μg/l for low AL, P = 0.014). Interpretation & conclusions: Build-up of AL was found in adolescent boys and was positively associated with life event stress. Iron nutrition and stress exhibited a positive association through hepcidin. The study provides a link between iron nutrition, physiological deregulation and stress. PMID:28139536

  9. Allostatic processes in the family.

    PubMed

    Repetti, Rena L; Robles, Theodore F; Reynolds, Bridget

    2011-08-01

    The concepts of allostatic load and allostatic processes can help psychologists understand how health trajectories are influenced by stressful childhood experiences in the family. This paper describes psychological pathways and two key allostatic mediators, the hypothalamic-pituitary-adrenal axis and the immune system, through which stressful early rearing conditions may influence adult mental and physical health. The action of meshed gears is introduced as a metaphor to illustrate how responses occurring within a brief time frame, for example, immediate reactions to stressors, can influence developmental and health processes unfolding over much longer spans of time. We identify early-developing psychological and biological response patterns that could link chronic stressors in childhood to later health outcomes. Some of these "precursor outcomes" (e.g., heightened vigilance and preparedness for threats; enhanced inflammatory and humoral responses to infectious microorganisms) appear to be aimed at protection from immediate dangers; they may reflect "adaptive trade-offs" that balance short-term survival advantages under harsh rearing conditions against disadvantages manifested later in development. Our analysis also suggests mechanisms that underlie resilience in risky family environments.

  10. A Longitudinal Investigation of Race, Socioeconomic Status, and Psychosocial Mediators of Allostatic Load in Midlife Women: Findings from the Study of Women’s Health Across the Nation

    PubMed Central

    Upchurch, Dawn M.; Stein, Judith; Greendale, Gail A.; Chyu, Laura; Tseng, Chi-Hong; Huang, Mei-Hua; Lewis, Tené T.; Kravitz, Howard M.; Seeman, Teresa

    2015-01-01

    Objectives This research sought to assess racial and SES differences in level and change in allostatic load (AL) over time in midlife women and to test whether psychosocial factors mediate these relationships. These factors were: discrimination, perceived stress, and hostility. Methods Longitudinal data obtained from the Study of Women’s Health Across the Nation SWAN were used (n = 2063; mean age at baseline = 46.0). Latent growth curve (LGC) models evaluated the impact of demographic, menopausal, and psychosocial variables on level and change in AL over 8 years. Results Direct effects: High levels of discrimination and hostility significantly predicted higher AL (path coefficients 0.05, 0.05 respectively). High perceived stress significantly predicted a faster rate of increase of AL (path coefficient 0.06). Racial and socioeconomic status (SES) differentials were present, with African American race (path coefficient 0.23), low income (path coefficient −0.15), and low education (path coefficient −0.08) significantly predicted high AL level. Indirect effects: Significant indirect effects were found for African American race, less income, and lower education through higher discrimination, perceived stress, and hostility on level and rate of AL. Conclusion This was one of the first studies that investigated AL over multiple time periods and results supported AL as a cumulative phenomenon, affected by multiple psychosocial and demographic factors. The results suggest the complex ways in which race, SES, and psychosocial factors operate to influence AL. PMID:25886828

  11. Schore's regulation theory: maternal-infant interaction in the NICU as a mechanism for reducing the effects of allostatic load on neurodevelopment in premature infants.

    PubMed

    Weber, Ashley M; Harrison, Tondi M; Steward, Deborah K

    2012-10-01

    Premature infants confront numerous physiologic and environmental stressors in the neonatal intensive care unit (NICU) that have the potential to permanently alter their neurodevelopment. Schore's regulation theory postulates that positive maternal-infant interactions can shape the infant's developmental outcomes through inducing mechanistic changes in brain structure and function. The purposes of this article are to explain the regulation of infant neurobiological processes during interactions between mothers and healthy infants in the context of Schore's theory, to identify threats to these processes for premature infants, and to propose principles of clinical practice and areas of research necessary to establish a supportive environment and prevent or reduce maladaptive consequences for these vulnerable infants. A premature birth results in the disruption of neurodevelopment at a critical time. Chronic exposure to stressors related to the NICU environment overwhelms immature physiologic and stress systems, resulting in significant allostatic load, as measured by long-term neurodevelopmental impairments in the premature infant. Positive maternal-infant interactions during NICU hospitalization and beyond have the potential to reduce neurologic deficits and maximize positive neurodevelopmental outcomes in premature infants. The quality of the maternal-infant interaction is affected not only by the infant's developing neurobiology but also by the mother's responses to the stressors surrounding a premature birth and mothering an infant in the NICU environment. Nurses can empower mothers to overcome these stressors, promote sensitive interactions with their infants, and facilitate neurodevelopment. Research is critically needed to develop and test nursing interventions directed at assisting mothers in supporting optimal neurodevelopment for their infants.

  12. Nativity differences in allostatic load by age, sex, and Hispanic background from the Hispanic Community Health Study/Study of Latinos.

    PubMed

    Salazar, Christian R; Strizich, Garrett; Seeman, Teresa E; Isasi, Carmen R; Gallo, Linda C; Avilés-Santa, M Larissa; Cai, Jianwen; Penedo, Frank J; Arguelles, Willian; Sanders, Anne E; Lipton, Richard B; Kaplan, Robert C

    2016-12-01

    Allostatic load (AL), an index of biological "wear and tear" on the body from cumulative exposure to stress, has been little studied in US Hispanics/Latinos. We investigated AL accumulation patterns by age, sex, and nativity in the Hispanic Community Health Study/Study of Latinos. We studied 15,830 Hispanic/Latinos of Mexican, Cuban, Dominican, Puerto Rican, Central and South American descent aged 18-74 years, 77% of whom were foreign-born. Consistent with the conceptualization of AL, we developed an index based upon 16 physiological markers that spanned the cardiometabolic, parasympathetic, and inflammatory systems. We computed mean adjusted AL scores using log-linear models across age-groups (18-44, 45-54, 55-74 years), by sex and nativity status. Among foreign-born individuals, differences in AL by duration of residence in the US (<10, ≥10 years) and age at migration (<24, ≥24 years) were also examined. In persons younger than 55 years old, after controlling for socioeconomic and behavioral factors, AL was highest among US-born individuals, intermediate in foreign-born Hispanics/Latinos with longer duration in the US (≥10 years), and lowest among those with shorter duration in the US (<10 years) (P <0.0001 for increasing trend). Similarly, AL increased among the foreign-born with earlier age at immigration. These trends were less pronounced among individuals ≥55 years of age. Similar patterns were observed across all Hispanic/Latino heritage groups (P for interaction=0.5). Our findings support both a "healthy immigrant" pattern and a loss of health advantage over time among US Hispanics/Latinos of diverse heritages.

  13. Relationship of Serum Vitamin D Concentrations and Allostatic Load as a Measure of Cumulative Biological Risk among the US Population: A Cross-Sectional Study

    PubMed Central

    Frei, Regina; Haile, Sarah R.; Mutsch, Margot; Rohrmann, Sabine

    2015-01-01

    Introduction The allostatic load (AL) index is a multi-systemic measure of physiologic dysregulation known to be associated with chronic exposure to stress and adverse health outcomes. We examined the relationship between AL and serum 25-hydroxyvitamin D (25(OH)D) concentration in non-institutionalized US adults. Methods Data from the Third National Health and Nutrition Examination Survey (NHANES III, 1988–94) were used to calculate two versions of AL including 9 biomarkers and another two with 14 biomarkers (systolic and diastolic blood pressure, pulse rate, serum cholesterol, serum HDL-cholesterol, glycated hemoglobin, sex-specific waist-to-hip ratio, serum albumin, and serum C-reactive protein for AL1, and, additionally body mass index, serum triglyceride, serum creatinine, and serum herpes I & II antibodies for AL2), each set defined by predefined cut-offs or by quartiles. Serum vitamin D concentration was ranked into quartiles. Logistic regression, Poisson regression and linear regression were used to examine the association of serum 25(OH)D concentrations on AL, after adjusting for biological, physiological, socioeconomic, lifestyle, and health variables. Results Odds Ratios (OR) for high AL of the lowest 25(OH)D serum quartile were between 1.45 (95% CI: 1.28, 1.67) and 1.79 (95% CI: 1.39, 2.32) for the fully adjusted model, depending on AL version. Inverse relationships between vitamin D serum concentrations were observed for all AL versions and every adjustment. This relationship was consistent after stratification by sex, age or ethnic background. Sensitivity to low 25(OH)D concentrations was highest among the youngest group (20–39 years) with an OR of 2.11 (95% CI: 1.63, 2.73) for the lowest vitamin D quartile Q1. Conclusions Vitamin D had a consistent and statistically significant inverse association with all tested models of high AL, which remained consistent after adjusting for biological, socioeconomic, lifestyle and health variables. Our study

  14. Perinatal distress in women in low- and middle-income countries: allostatic load as a framework to examine the effect of perinatal distress on preterm birth and infant health.

    PubMed

    Premji, Shahirose

    2014-12-01

    In low- and middle-income countries (LMIC), determinants of women's and children's health are complex and differential vulnerability may exist to risk factors of perinatal distress and preterm birth. We examined the contribution of maternal perinatal distress on preterm birth and infant health in terms of infant survival and mother-infant interaction. A critical narrative and interpretive literature review was conducted. Peer-reviewed electronic databases (MEDLINE, Embase, Global Health, CINHAL), grey literature, and reference lists were searched, followed by a consultation exercise. The literature was predominantly from high-income countries. We identify determinants of perinatal distress and explicate changes in the hypothalamic-pituitary-adrenal axis, sympathetic, immune and cardiovascular systems, and behavioral responses resulting in pathophysiological effects. We suggest cultural-neutral composite measures of allostatic mediators (i.e., several biomarkers) of maternal perinatal distress as objective indicators of dysregulation in body systems in pregnant women in LMIC. Understanding causal links of maternal perinatal distress to preterm birth in women in LMIC should be a priority. The roles of allostasis and allostatic load are considered within the context of the health of pregnant women and fetuses/newborns in LMIC with emphasis on identifying objective indicators of the level of perinatal distress and protective factors or processes contributing to resilience while facing toxic stress. We propose a prospective study design with multiple measures across pregnancy and postpartum requiring complex statistical modeling. Building research capacity through partnering researchers in high-income countries and LMIC and reflecting on unique ethical challenges will be important to generating new knowledge in LMIC.

  15. Rate of loading parameters for vertically loaded piles in clay

    SciTech Connect

    Briaud, J.L.; Felio, G.Y.; Garland, E.

    1984-05-01

    The analysis of 152 laboratory tests and 32 pile load tests confirms that for clays, the faster the rate of loading, the higher the undrained shear strength and the higher the pile capacity. The data shows that the gain in undrained shear strength due to increasing rate of loading increases with increasing water content, plasticity index, liquidity index, overconsolidation ratio but with decreasing undrained shear strength. A simple model is proposed to quantify the rate of loading effects on undrained shear strength. The viscous exponent n which is the main parameter of the model can be measured by conventional laboratory tests or possibly by cone penetrometer testing, or as a last resort by the proposed empirical correlations to index properties. This model is used to develop rate dependent t-z curves and a computer program to predict the response of a pile subjected to a certain rate of vertical loading. The model and the program are checked by comparing the predicted and measured behavior of two piles.

  16. A groundwork for allostatic neuro-education.

    PubMed

    Gerdes, Lee; Tegeler, Charles H; Lee, Sung W

    2015-01-01

    We propose to enliven educational practice by marrying a conception of education as guided human development, to an advanced scientific understanding of the brain known as allostasis (stability through change). The result is a groundwork for allostatic neuro-education (GANE). Education as development encompasses practices including the organic (homeschooling and related traditions), cognitive acquisition (emphasis on standards and testing), and the constructivist (aimed to support adaptive creativity for both learner and society). Allostasis views change to be the norm in biology, defines success in contexts of complex natural environments rather than controlled settings, and identifies the brain as the organ of central command. Allostatic neuro-education contrasts with education focused dominantly on testing, or neuroscience based on homeostasis (stability through constancy). The GANE perspective is to view learners in terms of their neurodevelopmental trajectories; its objective is to support authentic freedom, mediated by competent, integrated, and expansive executive functionality (concordant with the philosophy of freedom of Rudolf Steiner); and its strategy is to be attuned to rhythms in various forms (including those of autonomic arousal described in polyvagal theory) so as to enable experiential excitement for learning. The GANE presents a variety of testable hypotheses, and studies that explore prevention or mitigation of the effects of early life adversity or toxic stress on learning and development may be of particular importance. Case studies are presented illustrating use of allostatic neurotechnology by an adolescent male carrying diagnoses of Asperger's syndrome and attention-deficit hyperactivity disorder, and a grade school girl with reading difficulties. The GANE is intended as a re-visioning of education that may serve both learners and society to be better prepared for the accelerating changes of the 21st century.

  17. A groundwork for allostatic neuro-education

    PubMed Central

    Gerdes, Lee; Tegeler, Charles H.; Lee, Sung W.

    2015-01-01

    We propose to enliven educational practice by marrying a conception of education as guided human development, to an advanced scientific understanding of the brain known as allostasis (stability through change). The result is a groundwork for allostatic neuro-education (GANE). Education as development encompasses practices including the organic (homeschooling and related traditions), cognitive acquisition (emphasis on standards and testing), and the constructivist (aimed to support adaptive creativity for both learner and society). Allostasis views change to be the norm in biology, defines success in contexts of complex natural environments rather than controlled settings, and identifies the brain as the organ of central command. Allostatic neuro-education contrasts with education focused dominantly on testing, or neuroscience based on homeostasis (stability through constancy). The GANE perspective is to view learners in terms of their neurodevelopmental trajectories; its objective is to support authentic freedom, mediated by competent, integrated, and expansive executive functionality (concordant with the philosophy of freedom of Rudolf Steiner); and its strategy is to be attuned to rhythms in various forms (including those of autonomic arousal described in polyvagal theory) so as to enable experiential excitement for learning. The GANE presents a variety of testable hypotheses, and studies that explore prevention or mitigation of the effects of early life adversity or toxic stress on learning and development may be of particular importance. Case studies are presented illustrating use of allostatic neurotechnology by an adolescent male carrying diagnoses of Asperger’s syndrome and attention-deficit hyperactivity disorder, and a grade school girl with reading difficulties. The GANE is intended as a re-visioning of education that may serve both learners and society to be better prepared for the accelerating changes of the 21st century. PMID:26347688

  18. Minimizing Load Effects on NA4 Gear Vibration Diagnostic Parameter

    NASA Technical Reports Server (NTRS)

    Dempsey, Paula J.; Zakrajsek, James J.

    2001-01-01

    NA4 is a vibration diagnostic parameter, developed by researchers at NASA Glenn Research Center, for health monitoring of gears in helicopter transmissions. The NA4 reacts to the onset of gear pitting damage and continues to react to the damage as it spreads. This research also indicates NA4 reacts similarly to load variations. The sensitivity of NA4 to load changes will substantially affect its performance on a helicopter gearbox that experiences continuously changing load throughout its flight regimes. The parameter NA4 has been used to monitor gear fatigue tests at constant load. At constant load, NA4 effectively detects the onset of pitting damage and tracks damage severity. Previous research also shows that NA4 reacts to changes in load applied to the gears in the same way it reacts to the onset of pitting damage. The method used to calculate NA4 was modified to minimize these load effects. The modified NA4 parameter was applied to four sets of experimental data. Results indicate the modified NA4 is no longer sensitive to load changes, but remains sensitive to pitting damage.

  19. Continuous damage parameter calculation under thermo-mechanical random loading.

    PubMed

    Nagode, Marko

    2014-01-01

    The paper presents a method on how the mean stress effect on fatigue damage can be taken into account under an arbitrary low cycle thermo-mechanical loading. From known stress, elastoplastic strain and temperature histories the cycle amplitudes and cycle mean values are extracted and the damage parameter is computed. In contrast to the existing methods the proposed method enables continuous damage parameter computation without the need of waiting for the cycles to close. The limitations of the standardized damage parameters are thus surpassed. The damage parameters derived initially for closed and isothermal cycles assuming that the elastoplastic stress-strain response follows the Masing and memory rules can now be used to take the mean stress effect into account under an arbitrary low cycle thermo-mechanical loading. The method includes:•stress and elastoplastic strain history transformation into the corresponding amplitude and mean values;•stress and elastoplastic strain amplitude and mean value transformation into the damage parameter amplitude history;•damage parameter amplitude history transformation into the damage parameter history.

  20. Continuous damage parameter calculation under thermo-mechanical random loading

    PubMed Central

    Nagode, Marko

    2014-01-01

    The paper presents a method on how the mean stress effect on fatigue damage can be taken into account under an arbitrary low cycle thermo-mechanical loading. From known stress, elastoplastic strain and temperature histories the cycle amplitudes and cycle mean values are extracted and the damage parameter is computed. In contrast to the existing methods the proposed method enables continuous damage parameter computation without the need of waiting for the cycles to close. The limitations of the standardized damage parameters are thus surpassed. The damage parameters derived initially for closed and isothermal cycles assuming that the elastoplastic stress–strain response follows the Masing and memory rules can now be used to take the mean stress effect into account under an arbitrary low cycle thermo-mechanical loading. The method includes:•stress and elastoplastic strain history transformation into the corresponding amplitude and mean values;•stress and elastoplastic strain amplitude and mean value transformation into the damage parameter amplitude history;•damage parameter amplitude history transformation into the damage parameter history. PMID:26150939

  1. Sensitivity of lumbar spine loading to anatomical parameters.

    PubMed

    Putzer, Michael; Ehrlich, Ingo; Rasmussen, John; Gebbeken, Norbert; Dendorfer, Sebastian

    2016-04-11

    Musculoskeletal simulations of lumbar spine loading rely on a geometrical representation of the anatomy. However, this data has an inherent inaccuracy. This study evaluates the influence of defined geometrical parameters on lumbar spine loading utilising five parametrised musculoskeletal lumbar spine models for four different postures. The influence of the dimensions of vertebral body, disc, posterior parts of the vertebrae as well as the curvature of the lumbar spine was studied. Additionally, simulations with combinations of selected parameters were conducted. Changes in L4/L5 resultant joint force were used as outcome variable. Variations of the vertebral body height, disc height, transverse process width and the curvature of the lumbar spine were the most influential. These parameters can be easily acquired from X-rays and should be used to morph a musculoskeletal lumbar spine model for subject-specific approaches with respect to bone geometry. Furthermore, the model was very sensitive to uncommon configurations and therefore, it is advised that stiffness properties of discs and ligaments should be individualised.

  2. Sediment load estimation using statistical distributions with streamflow dependent parameters

    NASA Astrophysics Data System (ADS)

    Mailhot, A.; Rousseau, A. N.; Talbot, G.; Quilbé, R.

    2005-12-01

    The classical approaches to estimate sediment and chemical loads are all deterministic: averaging methods, ratio estimators, regression methods (rating curves) and planning level load estimation methods. However, none of these methods is satisfactory since they are often inaccurate and do not take into account nor quantify uncertainty. To fill this gap, statistical methods have to be investigated. This presentation proposes a new statistical method in which sediment concentration is assimilated to a random variable and is described by distribution functions. Three types of distributions are considered: Log-Normal, Gamma and Weibull distributions. Correlation between sediment concentrations and streamflows is integrated to the model by assuming that distribution parameters (mean and coefficient of variation) are related to streamflow using several different functional forms: exponential, quadratic and power law forms for the mean, constant and linear for the coefficient of variation. Parameter estimation is realized through maximization of the likelihood function. This approach is applied on a data set (1989 to 2004) from the Beaurivage River (Quebec, Canada) with weekly to monthly sampling for sediment concentration. A comparison of different models (selection of a distribution function with functional forms relating the mean and the coefficient of variation to streamflow) shows that the Log-Normal distribution with power law mean and coefficient of variation independent of streamflow provides the best result. When comparing annual load results with those obtained using deterministic methods, we observe that ratio estimators values are rarely within the [0.1, 0.9] quantile interval. For the 1997-2004 period, ratio estimator values are almost systematically smaller than the 0.1 quantile. This could presumably be due to the small number of sediment concentration samples for these years. This study suggests that, if deterministic methods such as the ratio estimator

  3. Cumulative Risk, Maternal Responsiveness, and Allostatic Load among Young Adolescents

    ERIC Educational Resources Information Center

    Evans, Gary W.; Kim, Pilyoung; Ting, Albert H.; Tesher, Harris B.; Shannis, Dana

    2007-01-01

    The purpose of this study was to examine the impact of cumulative risk exposure in concert with maternal responsiveness on physiological indicators of chronic stress in children and youth. Middle-school children exposed to greater accumulated psychosocial (e.g., family turmoil, poverty) and physical (e.g., crowding, substandard housing) risk…

  4. Allostatic Load: Definition and Relation to Disability in Hispanic Elders

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Health disparities among minority populations are important problems that may become amplified with age, contributing to development of physical disability. Surveys of Puerto Ricans in the US mainland have consistently shown high rates of disability. One hypothesis for this is lifelong exposure to s...

  5. On dynamic loads in parallel shaft transmissions. 2: Parameter study

    NASA Technical Reports Server (NTRS)

    Lin, Edward Hsiang-Hsi; Huston, Ronald L.; Coy, John J.

    1987-01-01

    Solutions to the governing equations of a spur gear transmission model, developed in NASA TM-100180 (AVSCOM TM-87-C-2), are presented. Factors affecting the dynamic load are identified. It is found that the dynamic load increases with operating speed up to a system natural frequency. At operating speeds beyond the natural frequency the dynamic load decreases dramatically. Also. it is found that the applied load and shaft inertia have little effect on the dynamic load. Damping and friction decrease the dynamic load. Finally, tooth stiffness has a significant effect on dynamic loading; the higher the stiffness, the lower the dynamic loading. Also, the higher the stiffness the higher the rotating speed required for dynamic response.

  6. Atmospheric pressure loading parameters from very long baseline interferometry observations

    NASA Technical Reports Server (NTRS)

    Macmillan, D. S.; Gipson, John M.

    1994-01-01

    Atmospheric mass loading produces a primarily vertical displacement of the Earth's crust. This displacement is correlated with surface pressure and is large enough to be detected by very long baseline interferometry (VLBI) measurements. Using the measured surface pressure at VLBI stations, we have estimated the atmospheric loading term for each station location directly from VLBI data acquired from 1979 to 1992. Our estimates of the vertical sensitivity to change in pressure range from 0 to -0.6 mm/mbar depending on the station. These estimates agree with inverted barometer model calculations (Manabe et al., 1991; vanDam and Herring, 1994) of the vertical displacement sensitivity computed by convolving actual pressure distributions with loading Green's functions. The pressure sensitivity tends to be smaller for stations near the coast, which is consistent with the inverted barometer hypothesis. Applying this estimated pressure loading correction in standard VLBI geodetic analysis improves the repeatability of estimated lengths of 25 out of 37 baselines that were measured at least 50 times. In a root-sum-square (rss) sense, the improvement generally increases with baseline length at a rate of about 0.3 to 0.6 ppb depending on whether the baseline stations are close to the coast. For the 5998-km baseline from Westford, Massachusetts, to Wettzell, Germany, the rss improvement is about 3.6 mm out of 11.0 mm. The average rss reduction of the vertical scatter for inland stations ranges from 2.7 to 5.4 mm.

  7. A Phenomenological Model for Circadian and Sleep Allostatic Modulation of Plasma Cortisol Concentration

    DTIC Science & Technology

    2012-09-25

    RJ, Ortega-Soto H, Huerto-Delgadillo L, Camacho- Arroyo I, Roldán-Roldán G, Tamarkin L. The effect of total sleep deprivation on plasma melatonin and...A phenomenological model for circadian and sleep allostatic modulation of plasma cortisol concentration David Thorsley,1 Rachel Leproult,2,3 Karine...2012 Thorsley D, Leproult R, Spiegel K, Reifman J. A phenomenological model for circadian and sleep allostatic modulation of plasma cortisol

  8. Influences of aerodynamic loads on hunting stability of high-speed railway vehicles and parameter studies

    NASA Astrophysics Data System (ADS)

    Zeng, Xiao-Hui; Wu, Han; Lai, Jiang; Sheng, Hong-Zhi

    2014-12-01

    The influences of steady aerodynamic loads on hunting stability of high-speed railway vehicles were investigated in this study. A mechanism is suggested to explain the change of hunting behavior due to actions of aerodynamic loads: the aerodynamic loads can change the position of vehicle system (consequently the contact relations), the wheel/rail normal contact forces, the gravitational restoring forces/moments and the creep forces/moments. A mathematical model for hunting stability incorporating such influences was developed. A computer program capable of incorporating the effects of aerodynamic loads based on the model was written, and the critical speeds were calculated using this program. The dependences of linear and nonlinear critical speeds on suspension parameters considering aerodynamic loads were analyzed by using the orthogonal test method, the results were also compared with the situations without aerodynamic loads. It is shown that the most dominant factors affecting linear and nonlinear critical speeds are different whether the aerodynamic loads considered or not. The damping of yaw damper is the most dominant influencing factor for linear critical speeds, while the damping of lateral damper is most dominant for nonlinear ones. When the influences of aerodynamic loads are considered, the linear critical speeds decrease with the rise of crosswind velocity, whereas it is not the case for the nonlinear critical speeds. The variation trends of critical speeds with suspension parameters can be significantly changed by aerodynamic loads. Combined actions of aerodynamic loads and suspension parameters also affect the critical speeds. The effects of such joint action are more obvious for nonlinear critical speeds.

  9. Experimental Parameters Affecting Stripping of Rare Earth Elements from Loaded Sorptive Media in Simulated Geothermal Brines

    SciTech Connect

    Dean Stull

    2016-05-24

    Experimental results from several studies exploring the impact of pH and acid volume on the stripping of rare earth elements (REEs) loaded onto ligand-based media via an active column. The REEs in this experiment were loaded onto the media through exposure to a simulated geothermal brine with known mineral concentrations. The data include the experiment results, rare earth element concentrations, and the experimental parameters varied.

  10. Comparison of vocal loading parameters in kindergarten and elementary school teachers.

    PubMed

    Remacle, Angélique; Morsomme, Dominique; Finck, Camille

    2014-04-01

    PURPOSE Although a global picture exists of teachers' voice demands in general, few studies have compared specific groups of teachers to determine whether some are more at risk than others. This study compared the vocal loadings of kindergarten and elementary school teachers; professional and nonprofessional vocal load were determined for both groups. METHOD Twelve kindergarten and 20 elementary school female teachers without voice problems were monitored during 1 workweek using the Ambulatory Phonation Monitor. Vocal loading parameters analyzed were F0, SPL, time dose, distance dose, and cycle dose. RESULTS Comparisons between the groups showed significantly higher cycle dose and distance dose for kindergarten teachers than for elementary school teachers, in both professional and nonprofessional environments. Professional and nonprofessional voice use comparisons showed significant differences for all parameters, indicating that vocal load was higher in the professional environment for both groups. CONCLUSIONS The higher vocal doses measured in kindergarten teachers suggest that particular attention should be paid to this specific group of teachers. Although nonprofessional vocal load is lower than professional vocal load, it is important to take both into account because of their cumulative effects.

  11. Calculations of high-frequency parameters of disc-loaded waveguides

    NASA Astrophysics Data System (ADS)

    Kaschiev, M. S.; Mamonov, V. N.; Obukhov, Yu. L.; Reshetnikova, K. A.; Rubin, S. B.

    1987-12-01

    Radio-technical parameters of a disc-loaded waveguide suitable for modeling two-beam acceleration are designed. Two series of calculations using the finite element method (MULTIMODE program) and restricted region method (ALF program) lead to coinciding resonance frequencies for rectangular-disc waveguide. The MULTIMODE program package is also used for the numerical simulation of the rounded-edge-disc waveguide, the field distribution picture and several energy parameters of the designed system.

  12. Body segment inertial parameters and low back load in individuals with central adiposity.

    PubMed

    Pryce, Robert; Kriellaars, Dean

    2014-09-22

    There is a paucity of information regarding the impact of central adiposity on the inertial characteristics of body segments. Deriving low back loads during lifting requires accurate estimate of inertial parameters. The purpose was to determine the body segment inertial parameters of people with central adiposity using a photogrammetric technique, and then to evaluate the impact on lumbar spine loading. Five participants with central adiposity (waist:hip ratio>0.9, waist circumference>102 cm) were compared to a normal BMI group. A 3D wireframe model of the surface topography was constructed, partitioned into 8 body segments and then body segment inertial parameters were calculated using volumetric integration assuming uniform segment densities for the segments. Central adiposity dependent increases in body segment parameters ranged from 12 to 400%, varying across segments (greatest for trunk) and parameters. The increase in mass distribution to the trunk was accompanied by an anterior and inferior shift of the centre of mass. A proximal shift in centre of mass was detected for the extremities, along with a reduction in mass distribution to the lower extremity. L5/S1 torques (392 vs 263 Nm) and compressive forces (5918 vs 3986 N) were substantially elevated in comparison to the normal BMI group, as well as in comparison to torques and forces predicted using published BSIP equations. Central adiposity resulted in substantial but non-uniform increases in inertial parameters resulting in task specific increases in torque and compressive loads arising from different inertial and physical components.

  13. Effect of Different Loads on Stroke and Coordination Parameters During Freestyle Semi-Tethered Swimming

    PubMed Central

    Dominguez-Castells, Rocio; Arellano, Raul

    2012-01-01

    The aim of this study was to analyse to what extent the use of different loads modifies freestyle stroke and coordination parameters during semi-tethered swimming, and to examine whether those changes are positive or negative to swimming performance. First, behaviour of swimming speed (v), stroke rate (SR) and stroke length (SL) with increasing loads was examined. Secondly, mean and peak speed of propulsive phases (propvmean and propvpeak) were analysed, as well as the relative difference between them (%v). Finally, index of coordination (IdC) was assessed. Eighteen male swimmers (22.10±4.31years, 1.79±0.07m, 76.74±9.00kg) performed 12.5m maximal sprints, pulling a different load each trial (0, 1.59, 2.21, 2.84, 3.46, 4.09, 4.71, 5.34, 5.96, 6.59, 7.21 and 7.84kg). Rest between repetitions was five minutes. Their feet were tied together, keeping a pull-buoy between legs and isolating the upper limb action. A speedometer was used to measure intra-cycle speed and the test was recorded by a frontal and a lateral underwater cameras. Variables v and SL decreased significantly when load increased, while SR remained constant (p<0.05). Propvmean and propvpeak decreased significantly with increasing loads (p<0.05). In contrast, %v grew when load rose (r = 0.922, p<0.01), being significantly different from free swimming above 4.71kg. For higher loads, swimmers did not manage to keep a constant velocity during a complete trial. IdC was found to increase with loads, significantly from 2.84kg (p<0.05). It was concluded that semi-tethered swimming is one training method useful to enhance swimmers’ performance, but load needs to be individually determined and carefully controlled. PMID:23486657

  14. Allostatic Self-efficacy: A Metacognitive Theory of Dyshomeostasis-Induced Fatigue and Depression

    PubMed Central

    Stephan, Klaas E.; Manjaly, Zina M.; Mathys, Christoph D.; Weber, Lilian A. E.; Paliwal, Saee; Gard, Tim; Tittgemeyer, Marc; Fleming, Stephen M.; Haker, Helene; Seth, Anil K.; Petzschner, Frederike H.

    2016-01-01

    This paper outlines a hierarchical Bayesian framework for interoception, homeostatic/allostatic control, and meta-cognition that connects fatigue and depression to the experience of chronic dyshomeostasis. Specifically, viewing interoception as the inversion of a generative model of viscerosensory inputs allows for a formal definition of dyshomeostasis (as chronically enhanced surprise about bodily signals, or, equivalently, low evidence for the brain's model of bodily states) and allostasis (as a change in prior beliefs or predictions which define setpoints for homeostatic reflex arcs). Critically, we propose that the performance of interoceptive-allostatic circuitry is monitored by a metacognitive layer that updates beliefs about the brain's capacity to successfully regulate bodily states (allostatic self-efficacy). In this framework, fatigue and depression can be understood as sequential responses to the interoceptive experience of dyshomeostasis and the ensuing metacognitive diagnosis of low allostatic self-efficacy. While fatigue might represent an early response with adaptive value (cf. sickness behavior), the experience of chronic dyshomeostasis may trigger a generalized belief of low self-efficacy and lack of control (cf. learned helplessness), resulting in depression. This perspective implies alternative pathophysiological mechanisms that are reflected by differential abnormalities in the effective connectivity of circuits for interoception and allostasis. We discuss suitably extended models of effective connectivity that could distinguish these connectivity patterns in individual patients and may help inform differential diagnosis of fatigue and depression in the future. PMID:27895566

  15. Parameters for successful implant integration revisited part II: algorithm for immediate loading diagnostic factors.

    PubMed

    Bahat, Oded; Sullivan, Richard M

    2010-05-01

    Immediate loading of dental implants has become a widely reported practice with success rates ranging from 70.8% to 100%. Although most studies have considered implant survival to be the only measure of success, a better definition includes the long-term stability of the hard and soft tissues around the implant(s) and other adjacent structures, as well as the long-term stability of all the restorative components. The parameters identified in 1981 by Albrektsson and colleagues as influencing the establishment and maintenance of osseointegration have been reconsidered in relation to immediate loading to improve the chances of achieving such success. Two of the six parameters (status of the bone/implant site and implant loading conditions) have preoperative diagnostic implications, whereas three (implant design, surgical technique, and implant finish) may compensate for less-than-ideal site and loading conditions. Factors affecting the outcome of immediate loading are reviewed to assist clinicians attempting to assess its risks and benefits.

  16. Thermodynamic parameters of mixtures with allowance for phase transition components under shock-wave loading

    NASA Astrophysics Data System (ADS)

    Kinelovskii, S. A.; Maevskii, K. K.

    2017-02-01

    The shock-wave synthesis and compaction using powder mixtures are the one of perspective directions of new materials creation. The results of numerical experiments on modeling of shock wave loading of mixtures with allowance for phase transition components in their composition are presented. The significant change in volume in the region of phase transition components included in the mixtures allows us to expand the range of variation of thermodynamic parameters of the mixtures under shock wave loading. The calculation model is based on the assumption that all components of mixture under shock-wave loading are in thermodynamic equilibrium (model TEC). The model TEC allows us to describe the region of the polymorphic phase transition, considering the material in the region of phase transition as a mixture of low-pressure phase and high-pressure phase. The good agreement of these model calculations with the data of different authors defined on the basis of experiments is obtained. Thermodynamic parameters of the nitrides mixture, solid and porous mixtures with quartz as component were reliably described. This model is useful for determining the compositions and volume fractions of the components of the mixture to obtain the specified parameters of solid and porous materials under shock-wave loading.

  17. Formulation parameters influencing the physicochemical characteristics of rosiglitazone-loaded cationic lipid emulsion.

    PubMed

    Davaa, Enkhzaya; Park, Jeong-Sook

    2012-07-01

    To enhance the solubility of rosiglitazone, rosiglitazone-loaded cationic lipid emulsion was formulated using cationic lipid DOTAP, DOPE, castor oil, tween 20, and tween 80. The formulation parameters in terms of droplet size were optimized focused on the effect of the cationic lipid emulsion composition ratio on drug encapsulating efficiency, in vitro drug release, and cellular uptake of the rosiglitazone-loaded emulsion. Droplet sizes of a blank cationic emulsion and a rosiglitazone-loaded cationic emulsion ranged between 195-230 nm and 210-290 nm, respectively. The encapsulation efficiency of the rosiglitazone-loaded emulsion was more than 90%. The rosiglitazone-loaded cationic emulsion improved in vitro drug release over the drug alone and showed a much higher cellular uptake than rosiglitazone alone. Moreover, drug loading in cationic emulsions increased cellular uptake of rosiglitazone in insulin-resistant HepG2 cells more than the normal HepG2 cells. Taken together, these results indicate that cationic lipid emulsions could be a potential delivery system for rosiglitazone and could enhance its cellular uptake efficiency into target cells.

  18. Parameter uncertainty-based pattern identification and optimization for robust decision making on watershed load reduction

    NASA Astrophysics Data System (ADS)

    Jiang, Qingsong; Su, Han; Liu, Yong; Zou, Rui; Ye, Rui; Guo, Huaicheng

    2017-04-01

    Nutrients loading reduction in watershed is essential for lake restoration from eutrophication. The efficient and optimal decision-making on loading reduction is generally based on water quality modeling and the quantitative identification of nutrient sources at the watershed scale. The modeling process is influenced inevitably by inherent uncertainties, especially by uncertain parameters due to equifinality. Therefore, the emerging question is: if there is parameter uncertainty, how to ensure the robustness of the optimal decisions? Based on simulation-optimization models, an integrated approach of pattern identification and analysis of robustness was proposed in this study that focuses on the impact of parameter uncertainty in water quality modeling. Here the pattern represents the discernable regularity of solutions for load reduction under multiple parameter sets. Pattern identification is achieved by using a hybrid clustering analysis (i.e., Ward-Hierarchical and K-means), which was flexible and efficient in analyzing Lake Bali near the Yangtze River in China. The results demonstrated that urban domestic nutrient load is the most potential source that should be reduced, and there are two patterns for Total Nitrogen (TN) reduction and three patterns for Total Phosphorus (TP) reduction. The patterns indicated different total reduction of nutrient loads, which reflect diverse decision preferences. The robust solution was identified by the highest accomplishment with the water quality at monitoring stations that were improved uniformly with this solution. We conducted a process analysis of robust decision-making that was based on pattern identification and uncertainty, which provides effective support for decision-making with preference under uncertainty.

  19. Controller design for wind turbine load reduction via multiobjective parameter synthesis

    NASA Astrophysics Data System (ADS)

    Hoffmann, A. F.; Weiβ, F. A.

    2016-09-01

    During the design process for a wind turbine load reduction controller many different, sometimes conflicting requirements must be fulfilled simultaneously. If the requirements can be expressed as mathematical criteria, such a design problem can be solved by a criterion-vector and multi-objective design optimization. The software environment MOPS (Multi-Objective Parameter Synthesis) supports the engineer for such a design optimization. In this paper MOPS is applied to design a multi-objective load reduction controller for the well-known DTU 10 MW reference wind turbine. A significant reduction in the fatigue criteria especially the blade damage can be reached by the use of an additional Individual Pitch Controller (IPC) and an additional tower damper. This reduction is reached as a trade-off with an increase of actuator load.

  20. Derivatives of buckling loads and vibration frequencies with respect to stiffness and initial strain parameters

    NASA Technical Reports Server (NTRS)

    Haftka, Raphael T.; Cohen, Gerald A.; Mroz, Zenon

    1990-01-01

    A uniform variational approach to sensitivity analysis of vibration frequencies and bifurcation loads of nonlinear structures is developed. Two methods of calculating the sensitivities of bifurcation buckling loads and vibration frequencies of nonlinear structures, with respect to stiffness and initial strain parameters, are presented. A direct method requires calculation of derivatives of the prebuckling state with respect to these parameters. An adjoint method bypasses the need for these derivatives by using instead the strain field associated with the second-order postbuckling state. An operator notation is used and the derivation is based on the principle of virtual work. The derivative computations are easily implemented in structural analysis programs. This is demonstrated by examples using a general purpose, finite element program and a shell-of-revolution program.

  1. Spatiotemporal Parameters are not Substantially Influenced by Load Carriage or Inclination During Treadmill and Overground Walking

    PubMed Central

    Seay, Joseph F.; Gregorczyk, Karen N.; Hasselquist, Leif

    2016-01-01

    Abstract Influences of load carriage and inclination on spatiotemporal parameters were examined during treadmill and overground walking. Ten soldiers walked on a treadmill and overground with three load conditions (00 kg, 20 kg, 40 kg) during level, uphill (6% grade) and downhill (-6% grade) inclinations at self-selected speed, which was constant across conditions. Mean values and standard deviations for double support percentage, stride length and a step rate were compared across conditions. Double support percentage increased with load and inclination change from uphill to level walking, with a 0.4% stance greater increase at the 20 kg condition compared to 00 kg. As inclination changed from uphill to downhill, the step rate increased more overground (4.3 ± 3.5 steps/min) than during treadmill walking (1.7 ± 2.3 steps/min). For the 40 kg condition, the standard deviations were larger than the 00 kg condition for both the step rate and double support percentage. There was no change between modes for step rate standard deviation. For overground compared to treadmill walking, standard deviation for stride length and double support percentage increased and decreased, respectively. Changes in the load of up to 40 kg, inclination of 6% grade away from the level (i.e., uphill or downhill) and mode (treadmill and overground) produced small, yet statistically significant changes in spatiotemporal parameters. Variability, as assessed by standard deviation, was not systematically lower during treadmill walking compared to overground walking. Due to the small magnitude of changes, treadmill walking appears to replicate the spatiotemporal parameters of overground walking. PMID:28149338

  2. Influence of occlusal loading on peri-implant clinical parameters. A pilot study

    PubMed Central

    Pellicer-Chover, Hilario; Viña-Almunia, José; Romero-Millán, Javier; Peñarrocha-Oltra, David; Peñarrocha-Diago, María

    2014-01-01

    Objectives: To investigate the relation between occlusal loading and peri-implant clinical parameters (probing depth, bleeding on probing, gingival retraction, width of keratinized mucosa, and crevicular fluid volume) in patients with implant-supported complete fixed prostheses in both arches. Material and Methods: This clinical study took place at the University of Valencia (Spain) dental clinic. It included patients attending the clinic for regular check-ups during at least 12 months after rehabilitation of both arches with implant-supported complete fixed ceramo-metallic prostheses. One study implant and one control implant were established for each patient using the T-Scan®III computerized system (Tesco, South Boston, USA). The maxillary implant closest to the point of maximum occlusal loading was taken as the study implant and the farthest (with least loading) as the control. Occlusal forces were registered with the T-Scan® III and then occlusal adjustment was performed to distribute occlusal forces correctly. Peri-implant clinical parameters were analyzed in both implants before and two and twelve months after occlusal adjustment. Results: Before occlusal adjustment, study group implants presented a higher mean volume of crevicular fluid (51.3±7.4 UP) than the control group (25.8±5.5 UP), with statistically significant difference. Two months after occlusal adjustment, there were no significant differences between groups (24.6±3.8 UP and 26±4.5 UP respectively) (p=0.977). After twelve months, no significant differences were found between groups (24.4±11.1 UP and 22.5±8.9 UP respectively) (p=0.323). For the other clinical parameters, no significant differences were identified between study and control implants at any of the study times (p>0.05). Conclusions: Study group implants receiving higher occlusal loading presented significantly higher volumes of crevicular fluid than control implants. Crevicular fluid volumes were similar in both groups two and

  3. External Load Affects Ground Reaction Force Parameters Non-uniformly during Running in Weightlessness

    NASA Technical Reports Server (NTRS)

    DeWitt, John; Schaffner, Grant; Laughlin, Mitzi; Loehr, James; Hagan, R. Donald

    2004-01-01

    Long-term exposure to microgravity induces detrimefits to the musculcskdetal system (Schneider et al., 1995; LeBlanc et al., 2000). Treadmill exercise is used onboard the International Space Station as an exercise countermeasure to musculoskeletal deconditioning due to spaceflight. During locomotive exercise in weightlessness (0G), crewmembers wear a harness attached to an external loading mechanism (EL). The EL pulls the crewmember toward the treadmill, and provides resistive load during the impact and propulsive phases of gait. The resulting forces may be important in stimulating bone maintenance (Turner, 1998). The EL can be applied via a bungee and carabineer clip configuration attached to the harness and can be manipulated to create varying amounts of load levels during exercise. Ground-based research performed using a vertically mounted treadmill found that peak ground reaction forces (GRF) during running at an EL of less than one body weight (BW) are less than those that occur during running in normal gravity (1G) (Davis et al., 1996). However, it is not known how the GRF are affected by the EL in a true OG environment. Locomotion while suspended may result in biomechanics that differ from free running. The purpose of this investigation was to determine how EL affects peak impact force, peak propulsive force, loading rate, and impulse of the GRF during running in 0G. It was hypothesized that increasing EL would result in increases in each GRF parameter.

  4. An Underfrequency Load Shedding Scheme with Minimal Knowledge of System Parameters

    NASA Astrophysics Data System (ADS)

    Joe, Athbel; Krishna, S.

    2015-02-01

    Underfrequency load shedding (UFLS) is a common practice to protect a power system during large generation deficit. The adaptive UFLS schemes proposed in the literature have the drawbacks such as requirement of transmission of local frequency measurements to a central location and knowledge of system parameters, such as inertia constant H and load damping constant D. In this paper, a UFLS scheme that uses only the local frequency measurements is proposed. The proposed method does not require prior knowledge of H and D. The scheme is developed for power systems with and without spinning reserve. The proposed scheme requires frequency measurements free from the oscillations at the swing mode frequencies. Use of an elliptic low pass filter to remove these oscillations is proposed. The scheme is tested on a 2 generator system and the 10 generator New England system. Performance of the scheme with power system stabilizer is also studied.

  5. Birth of the Allostatic Model: From Cannon's Biocracy to Critical Physiology.

    PubMed

    Arminjon, Mathieu

    2016-04-01

    Physiologists and historians are still debating what conceptually differentiates each of the three major modern theories of regulation: the constancy of the milieu intérieur, homeostasis and allostasis. Here I propose that these models incarnate two distinct regimes of politization of the life sciences. This perspective leads me to suggest that the historicization of physiological norms is intrinsic to the allostatic model, which thus divides it fundamentally from the two others. I analyze the allostatic model in the light of the Canguilhemian theory, showing how the former contributed to the development of a critical epistemology immune to both naturalist essentialism and social constructivism. With a unique clarity in the history of physiology, allostasis gives us a model of the convergence of historical epistemology and scientific practice. As such it played a key role in codifying the epistemological basis of certain current research programs that, in the fields of social epidemiology and feminist neuroscience, promote what we name here a critical physiology.

  6. Parameter identification of aggregated thermostatically controlled loads for smart grids using PDE techniques

    NASA Astrophysics Data System (ADS)

    Moura, Scott; Bendtsen, Jan; Ruiz, Victor

    2014-07-01

    This paper develops methods for model identification of aggregated thermostatically controlled loads (TCLs) in smart grids, via partial differential equation (PDE) techniques. Control of aggregated TCLs provides a promising opportunity to mitigate the mismatch between power generation and demand, thus enhancing grid reliability and enabling renewable energy penetration. To this end, this paper focuses on developing parameter identification algorithms for a PDE-based model of aggregated TCLs. First, a two-state boundary-coupled hyperbolic PDE model for homogenous TCL populations is derived. This model is extended to heterogeneous populations by including a diffusive term, which provides an elegant control-oriented model. Next, a passive parameter identification scheme and a swapping-based identification scheme are derived for the PDE model structure. Simulation results demonstrate the efficacy of each method under various autonomous and non-autonomous scenarios. The proposed models can subsequently be employed to provide system critical information for power system monitoring and control.

  7. Tumor Mutational Load and Immune Parameters across Metastatic Renal Cell Carcinoma Risk Groups.

    PubMed

    de Velasco, Guillermo; Miao, Diana; Voss, Martin H; Hakimi, A Ari; Hsieh, James J; Tannir, Nizar M; Tamboli, Pheroze; Appleman, Leonard J; Rathmell, W Kimryn; Van Allen, Eliezer M; Choueiri, Toni K

    2016-10-01

    Patients with metastatic renal cell carcinoma (mRCC) have better overall survival when treated with nivolumab, a cancer immunotherapy that targets the immune checkpoint inhibitor programmed cell death 1 (PD-1), rather than everolimus (a chemical inhibitor of mTOR and immunosuppressant). Poor-risk mRCC patients treated with nivolumab seemed to experience the greatest overall survival benefit, compared with patients with favorable or intermediate risk, in an analysis of the CheckMate-025 trial subgroup of the Memorial Sloan Kettering Cancer Center (MSKCC) prognostic risk groups. Here, we explore whether tumor mutational load and RNA expression of specific immune parameters could be segregated by prognostic MSKCC risk strata and explain the survival seen in the poor-risk group. We queried whole-exome transcriptome data in renal cell carcinoma patients (n = 54) included in The Cancer Genome Atlas who ultimately developed metastatic disease or were diagnosed with metastatic disease at presentation and did not receive immune checkpoint inhibitors. Nonsynonymous mutational load did not differ significantly by the MSKCC risk group, nor was the expression of cytolytic genes-granzyme A and perforin-or selected immune checkpoint molecules different across MSKCC risk groups. In conclusion, this analysis revealed that mutational load and expression of markers of an active tumor microenvironment did not correlate with MSKCC risk prognostic classification in mRCC. Cancer Immunol Res; 4(10); 820-2. ©2016 AACR.

  8. Thermodynamic parameters of heterogeneous materials under shock-wave loading in presentation of equilibrium model

    NASA Astrophysics Data System (ADS)

    Maevskii, K. K.; Kinelovskii, S. A.

    2016-11-01

    The results of numerical experiments on modeling of shock wave loading of solid and porous heterogeneous materials on the example of molybdenum and some alloys included molybdenum as a component are presented. A thermodynamically equilibrium model is applied to describe the behavior of solid and porous materials. This model ensures good compliance with the experiment in a wide range of pressures. The gas in pores, which is a component of the medium, is taken into account in this model. The equation of state of the Mie-Grüneisen type with allowance for the dependence of the Grüneisen coefficient on temperature is used for condensed phases. The applied model allows the behavior of the molybdenum with porosity from 1 to 3 to be calculated under shock-wave loading at pressures above 5 GPa in the one-velocity and one-temperature approximations, as well as on the assumption of equal pressures for all the phases. Computational results are compared with the well-known experimental results obtained by different authors. The model permits the shock-wave loading of solid and porous alloys with molybdenum in their composition to be described reliably solely by using species parameters.

  9. Resistance Against the Intrinsic Rate of Fracture Mechanics Parameters for Polymeric Materials Under Moderate Impact Loading

    NASA Astrophysics Data System (ADS)

    Lach, R.; Seidler, S.; Grellmann, W.

    2005-09-01

    This study contributes towards understanding crack toughness as resistance against the intrinsic rate of fracture mechanics parameters. Up to now only few investigations have been done under moderate impact loading conditions. Based on experimental investigations using the crack resistance (R) concept, it has been shown that the stop block method combined with the multiple-specimen technique is a unique method for polymers under impact loading conditions in comparison with different R-curve methods. Other methods for the determination of R curve such as the low-blow technique are normally not applicable for polymers due to their time-dependent mechanical properties. The crack-tip opening displacement (CTOD) rate is a measurement of the rate sensibility of stable fracture process depending on the type of deformation, which can provide deep insights into the micromechanics and activation mechanisms during the fracture processes. In the polymeric materials mostly investigated, one can understand the stable crack propagation with three-stage processes; crack-tip blunting/crack initiation, non-stationary stable crack growth and steady-state stable crack growth (an equilibrium state). In this stable crack propagation, the values of normalized CTOD rate converge rapidly to a ‘matrix’-specific threshold. The stop block method in the multiple-specimen technique assures the criteria of the time-independent strain field around the crack tip and constant crack speed therewith and the J-integral is a valid toughness parameter.

  10. Scaling up watershed model parameters--Flow and load simulations of the Edisto River Basin

    USGS Publications Warehouse

    Feaster, Toby D.; Benedict, Stephen T.; Clark, Jimmy M.; Bradley, Paul M.; Conrads, Paul A.

    2014-01-01

    The Edisto River is the longest and largest river system completely contained in South Carolina and is one of the longest free flowing blackwater rivers in the United States. The Edisto River basin also has fish-tissue mercury concentrations that are some of the highest recorded in the United States. As part of an effort by the U.S. Geological Survey to expand the understanding of relations among hydrologic, geochemical, and ecological processes that affect fish-tissue mercury concentrations within the Edisto River basin, analyses and simulations of the hydrology of the Edisto River basin were made with the topography-based hydrological model (TOPMODEL). The potential for scaling up a previous application of TOPMODEL for the McTier Creek watershed, which is a small headwater catchment to the Edisto River basin, was assessed. Scaling up was done in a step-wise process beginning with applying the calibration parameters, meteorological data, and topographic wetness index data from the McTier Creek TOPMODEL to the Edisto River TOPMODEL. Additional changes were made with subsequent simulations culminating in the best simulation, which included meteorological and topographic wetness index data from the Edisto River basin and updated calibration parameters for some of the TOPMODEL calibration parameters. Comparison of goodness-of-fit statistics between measured and simulated daily mean streamflow for the two models showed that with calibration, the Edisto River TOPMODEL produced slightly better results than the McTier Creek model, despite the significant difference in the drainage-area size at the outlet locations for the two models (30.7 and 2,725 square miles, respectively). Along with the TOPMODEL hydrologic simulations, a visualization tool (the Edisto River Data Viewer) was developed to help assess trends and influencing variables in the stream ecosystem. Incorporated into the visualization tool were the water-quality load models TOPLOAD, TOPLOAD-H, and LOADEST

  11. [Current trends and problems in the measurement of limb loading parameters during transosseous osteosynthesis using external fixation devices].

    PubMed

    Shuts, S A; Dzhafarova, O A; Shuts, B S

    1999-01-01

    The problem in question is whether it is reasonable to equip a conventional limb external fixation apparatus with means for the diagnosis of loading parameters: the forces and displacement of the opposite supporting elements of the apparatus. It is assumed that during distraction osteogenesis it is expedient to apply load to the limb by the load rate only at the initial stage of callus regeneration (the plastic or slightly elastic mechanical state) while the most effective way to do so is to act force at later stages. A number of functions derived from the modified parameters which might aid a physician to choose the optimum limb loading parameters at different stages of treatment were considered by using as example a hypothetical ring-type apparatus equipped with means for continuous measurement of current forces applied to the apparatus and current displacements of opposite ring blocks. Specifications for the measuring system of loading parameters were defined by using an Ilizarov apparatus as an example and why possible rough measurement errors may occur is revealed. The paper shows it necessary to develop methods for calculation of parasitic deformations, i.e. those of the loaded elements of the apparatus for the evaluation of the reciprocal displacement of bone fragments.

  12. Disturbance of wildlife by outdoor winter recreation: allostatic stress response and altered activity-energy budgets.

    PubMed

    Arlettaz, Raphaël; Nusslé, Sébastien; Baltic, Marjana; Vogel, Peter; Palme, Rupert; Jenni-Eiermann, Susanne; Patthey, Patrick; Genoud, Michel

    2015-07-01

    Anthropogenic disturbance of wildlife is of growing conservation concern, but we lack comprehensive approaches of its multiple negative effects. We investigated several effects of disturbance by winter outdoor sports on free-ranging alpine Black Grouse by simultaneously measuring their physiological and behavioral responses. We experimentally flushed radio-tagged Black Grouse from their snow burrows, once a day, during several successive days, and quantified their stress hormone levels (corticosterone metabolites in feces [FCM] collected. from individual snow burrows). We also measured feeding time allocation (activity budgets reconstructed from radio-emitted signals) in response to anthropogenic disturbance. Finally, we estimated the related extra energy expenditure that may be incurred: based on activity budgets, energy expenditure was modeled from measures of metabolism obtained from captive birds subjected to different ambient temperatures. The pattern of FCM excretion indicated the existence of a funneling effect as predicted by the allostatic theory of stress: initial stress hormone concentrations showed a wide inter-individual variation, which decreased during experimental flushing. Individuals with low initial pre-flushing FCM values augmented their concentration, while individuals with high initial FCM values lowered it. Experimental disturbance resulted in an extension of feeding duration during the following evening foraging bout, confirming the prediction that Black Grouse must compensate for the extra energy expenditure elicited by human disturbance. Birds with low initial baseline FCM concentrations were those that spent more time foraging. These FCM excretion and foraging patterns suggest that birds with high initial FCM concentrations might have been experiencing a situation of allostatic overload. The energetic model provides quantitative estimates of extra energy expenditure. A longer exposure to ambient temperatures outside the shelter of snow

  13. Plyometric Long Jump Training With Progressive Loading Improves Kinetic and Kinematic Swimming Start Parameters.

    PubMed

    Rebutini, Vanessa Z; Pereira, Gleber; Bohrer, Roberta C D; Ugrinowitsch, Carlos; Rodacki, André L F

    2016-09-01

    Rebutini, VZ, Pereira, G, Bohrer, RCD, Ugrinowitsch, C, and Rodacki, ALF. Plyometric long jump training with progressive loading improves kinetic and kinematic swimming start parameters. J Strength Cond Res 30(9): 2392-2398, 2016-This study was aimed to determine the effects of a plyometric long jump training program on torque around the lower limb joints and kinetic and kinematics parameters during the swimming jump start. Ten swimmers performed 3 identical assessment sessions, measuring hip and knee muscle extensors during maximal voluntary isometric contraction and kinetic and kinematics parameters during the swimming jump start, at 3 instants: INI (2 weeks before the training program, control period), PRE (2 weeks after INI measurements), and POST (24-48 hours after 9 weeks of training). There were no significant changes from INI to PRE measurements. However, the peak torque and rate of torque development increased significantly from PRE to POST measurements for both hip (47 and 108%) and knee (24 and 41%) joints. There were significant improvements to the horizontal force (7%), impulse (9%), and angle of resultant force (19%). In addition, there were significant improvements to the center of mass displacement (5%), horizontal takeoff velocity (16%), horizontal velocity at water entrance (22%), and peak angle velocity for the knee (15%) and hip joints (16%). Therefore, the plyometric long jump training protocol was effective to enhance torque around the lower limb joints and to control the resultant vector direction, to increase the swimming jump start performance. These findings suggest that coaches should use long jump training instead of vertical jump training to improve swimming start performance.

  14. Fat or lean: adjustment of endogenous energy stores to predictable and unpredictable changes in allostatic load

    USGS Publications Warehouse

    Schultner, Jannik; Kitaysky, Alexander S.; Welcker, Jorg; Hatch, Scott

    2013-01-01

    6. Overall, results of this study support the ‘lean and fit’ hypothesis. We conclude that increased energy stores may not necessarily reflect better environmental conditions experienced by individuals or predict their higher fitness. A major advantage of adopting a lean physique when environmental conditions allow may be the avoidance of additional energetic costs for moving a heavy body. In breeding seabirds, this advantage may be more important during chick-rearing. In the focal species, the secretion of glucocorticoids might be involved in regulation of energy stores within a life history stage but does not appear to mediate an adaptive shift in energy stores between the incubating and chick-rearing stages of reproduction.

  15. The Influence of the Load Model and other Parameters on the Dynamic Behavior of Curved-in-Plane Bridges

    NASA Astrophysics Data System (ADS)

    Raftoyiannis, Ioannis G.; Michaltsos, George T.

    2016-11-01

    This paper deals with the dynamic behavior of curved-in-plane bridges where the effect of the bridge curvature radius, the moving load (vehicle) speed, the truck cant angle, the deck surface conditions and, mainly, the response accuracy depending on the vehicle model used are investigated. Besides the above parameters, the influence of several loading models is studied as well, especially the models of a concentrated load, a damped mass-load, a sequence of two concentrated loads and a real vehicle aswell as a damped vehicle,where its width is taken into account. A 3-DOF model is considered for the analysis of the bridge, while the theoretical formulation is based on a continuum approach, which has been widely used in the literature to analyze such bridges.

  16. Erythrocyte-mediated delivery of pravastatin: in vitro study of effect of hypotonic lysis on biochemical parameters and loading efficiency.

    PubMed

    Harisa, Gamaleldin I; Ibrahim, Mohamed F; Alanazi, Fars K

    2012-08-01

    Exposure of erythrocytes to hypotonic lysis creates pores in the cell membrane, through which pravastatin can enter and become trapped, after resealing them with a suitable buffer. We investigated the effects of tonicity, incubation time and drug concentration on drug loading into erythrocytes. Furthermore, we investigate the effects of pravastatin on erythrocyte oxidative stress markers and osmotic fragility behavior. Encapsulation was achieved using buffer solutions of different tonicities (0.5, 0.6 and 0.7% NaCl) and different drug concentrations (2, 4, 8 and 10 mg/mL) for a range of incubation times (15, 30, 60 and 120 min). The results demonstrated that controlled hypotonic lysis could entrap pravastatin in human erythrocytes, with acceptable loading parameters. The highest loading (34%) was achieved at 0.6% NaCl and 10 mg/mL pravastatin for 60 min incubation. At this pravastatin concentration, oxidative stress markers were similar to those seen in controls, and fragility and hematological parameters were unaffected in drug-loaded erythrocytes. These results indicate that the loading process and pravastatin concentration had no deleterious effects on the structure of pravastatin-loaded erythrocytes, suggesting that they may therefore have a similar life span to normal cells. Pravastatin-loaded erythrocytes may thus provide an effective extended-release-delivery system for pravastatin.

  17. Nanoparticle Drug Loading as a Design Parameter to Improve Docetaxel Pharmacokinetics and Efficacy

    PubMed Central

    Chu, Kevin S.; Schorzman, Allison N.; Finniss, Mathew C.; Bowerman, Charles J.; Peng, Lei; Luft, J. Christopher; Madden, Andrew; Wang, Andrew Z.; Zamboni, William C.; DeSimone, Joseph M.

    2013-01-01

    Nanoparticle (NP) drug loading is one of the key defining characteristics of a NP formulation. However, the effect of NP drug loading on therapeutic efficacy and pharmacokinetics has not been thoroughly evaluated. Herein, we characterized the efficacy, toxicity and pharmacokinetic properties of NP docetaxel formulations that have differential drug loading but are otherwise identical. Particle Replication in Non-wetting Templates (PRINT®), a soft-lithography fabrication technique, was used to formulate NPs with identical size, shape and surface chemistry, but with variable docetaxel loading. The lower weight loading (9%-NP) of docetaxel was found to have a superior pharmacokinetic profile and enhanced efficacy in a murine cancer model when compared to that of a higher docetaxel loading (20%-NP). The 9%-NP docetaxel increased plasma and tumor docetaxel exposure and reduced liver, spleen and lung exposure when compared to that of 20%-NP docetaxel. PMID:23899444

  18. Comparison of Vocal Loading Parameters in Kindergarten and Elementary School Teachers

    ERIC Educational Resources Information Center

    Remacle, Angélique; Morsomme, Dominique; Finck, Camille

    2014-01-01

    Purpose: Although a global picture exists of teachers' voice demands in general, few studies have compared specific groups of teachers to determine whether some are more at risk than others. This study compared the vocal loadings of kindergarten and elementary school teachers; professional and nonprofessional vocal load were determined for…

  19. Mechanical Behaviors and Elastic Parameters of Laminated Fabric URETEK3216LV Subjected to Uniaxial and Biaxial Loading

    NASA Astrophysics Data System (ADS)

    Chen, Jianwen; Chen, Wujun; Wang, Mingyang; Ding, Yong; Zhou, Han; Zhao, Bing; Fan, Jin

    2017-01-01

    A comprehensive experimental study of the laminated fabric URETEK3216LV subjected to mono-uniaxial, uniaxial cyclic and biaxial cyclic loading was performed to expose the detailed mechanical behaviors and determine proper elastic parameters for the laminated fabrics under specific stress states. The elastic modulus-strain curves and elastic parameter response surfaces were used to reveal the mechanical behaviors, and a weighted average method of integrals was proposed to calculate the elastic parameters for different stress states. Results show that typical stress-strain curves consist of three distinct regions during loading: crimp region, nonlinear transition region and yarn extension region, which is consistent with those of the constitutive yarns. The elastic parameters and mechanical behaviors of the laminated fabric are stress-state specific, and they vary noticeably with the experimental protocols, stress ratios and stress levels. The proposed method is feasible to evaluate the elastic parameters no matter what stress states the materials are subjected to, and thus it may offer potential access to obtain accurate design and analysis of the airship structures under different loading conditions.

  20. Model measurement based identification of Francis turbine vortex rope parameters for prototype part load pressure and power pulsation prediction

    NASA Astrophysics Data System (ADS)

    Manderla, M.; Weber, W.; Koutnik, J.

    2016-11-01

    Pressure and power fluctuations of hydro-electric power plants in part-load operation are an important measure for the quality of the power which is delivered to the electrical grid. It is well known that the unsteadiness is driven by the flow patterns in the draft tube where a vortex rope is present. However, until today the equivalent vortex rope parameters for common numerical 1D-models are a major source of uncertainty. In this work, a new optimization-based grey box method for experimental vortex rope modelling and parameter identification is presented. The combination of analytical vortex rope and test rig modelling and the usage of dynamic measurements allow the identification of the unknown vortex rope parameters. Upscaling from model to prototype size is achieved via existing nondimensional parameters. In this work, a new experimental setup and system identification method is proposed which are suitable for the determination of the full set of part load vortex rope parameters in the lab. For the vortex rope, a symmetric model with cavity compliance, bulk viscosity and two pressure excitation sources is developed and implemented which shows the best correspondence with available measurement data. Due to the non-dimensional parameter definition, scaling is possible. This finally provides a complete method for the prediction of prototype part-load pressure and power oscillations. Since the proposed method is based on a simple limited control domain, limited modelling effort and also small modelling uncertainties are some major advantages. Due to the generality of the approach, a future application to other operating conditions such as full load will be straightforward.

  1. Thermodynamic parameters for mixtures of quartz under shock wave loading in views of the equilibrium model

    SciTech Connect

    Maevskii, K. K. Kinelovskii, S. A.

    2015-10-27

    The numerical results of modeling of shock wave loading of mixtures with the SiO{sub 2} component are presented. The TEC (thermodynamic equilibrium component) model is employed to describe the behavior of solid and porous multicomponent mixtures and alloys under shock wave loading. State equations of a Mie–Grüneisen type are used to describe the behavior of condensed phases, taking into account the temperature dependence of the Grüneisen coefficient, gas in pores is one of the components of the environment. The model is based on the assumption that all components of the mixture under shock-wave loading are in thermodynamic equilibrium. The calculation results are compared with the experimental data derived by various authors. The behavior of the mixture containing components with a phase transition under high dynamic loads is described.

  2. Effect of custom-made and prefabricated insoles on plantar loading parameters during running with and without fatigue.

    PubMed

    Lucas-Cuevas, Angel Gabriel; Pérez-Soriano, Pedro; Llana-Belloch, Salvador; Macián-Romero, Cecili; Sánchez-Zuriaga, Daniel

    2014-01-01

    Controversy exists whether custom-made insoles are more effective in reducing plantar loading compared to prefabricated insoles. Forty recreational athletes ran using custom-made, prefabricated, and the original insoles of their running shoes, at rest and after a fatigue run. Contact time, stride rate, and plantar loading parameters were measured. Neither the insole conditions nor the fatigue state modified contact time and stride rate. Addressing prevention of running injuries, post-fatigue loading values are of great interest. Custom-made insoles reduced the post-fatigue loading under the hallux (92 vs. 130 kPa, P < 0.05), medial midfoot (70 vs. 105 kPa, P < 0.01), and lateral midfoot (62 vs 96 kPa, P < 0.01). Prefabricated insoles provoked reductions in post-fatigue loading under the toes (120 vs. 175 kPa, P < 0.05), medial midfoot (71 vs. 105 kPa, P < 0.01), and lateral midfoot (68 vs. 96 kPa, P < 0.01). Regarding both study insoles, custom-made insoles reduced by 31% and 54% plantar loading under the medial and lateral heel compared to the prefabricated insoles. Finally, fatigue state did not influence plantar loading regardless the insole condition. In long-distance races, even a slight reduction in plantar loading at each foot strike may suppose a significant decrease in the overall stress experienced by the foot, and therefore the use of insoles may be an important protective mechanism for plantar overloading.

  3. Testing the Nanoparticle-Allostatic Cross Adaptation-Sensitization Model for Homeopathic Remedy Effects

    PubMed Central

    Bell, Iris R.; Koithan, Mary; Brooks, Audrey J.

    2012-01-01

    Key concepts of the Nanoparticle-Allostatic Cross-Adaptation-Sensitization (NPCAS) Model for the action of homeopathic remedies in living systems include source nanoparticles as low level environmental stressors, heterotypic hormesis, cross-adaptation, allostasis (stress response network), time-dependent sensitization with endogenous amplification and bidirectional change, and self-organizing complex adaptive systems. The model accommodates the requirement for measurable physical agents in the remedy (source nanoparticles and/or source adsorbed to silica nanoparticles). Hormetic adaptive responses in the organism, triggered by nanoparticles; bipolar, metaplastic change, dependent on the history of the organism. Clinical matching of the patient’s symptom picture, including modalities, to the symptom pattern that the source material can cause (cross-adaptation and cross-sensitization). Evidence for nanoparticle-related quantum macro-entanglement in homeopathic pathogenetic trials. This paper examines research implications of the model, discussing the following hypotheses: Variability in nanoparticle size, morphology, and aggregation affects remedy properties and reproducibility of findings. Homeopathic remedies modulate adaptive allostatic responses, with multiple dynamic short- and long-term effects. Simillimum remedy nanoparticles, as novel mild stressors corresponding to the organism’s dysfunction initiate time-dependent cross-sensitization, reversing the direction of dysfunctional reactivity to environmental stressors. The NPCAS model suggests a way forward for systematic research on homeopathy. The central proposition is that homeopathic treatment is a form of nanomedicine acting by modulation of endogenous adaptation and metaplastic amplification processes in the organism to enhance long-term systemic resilience and health. PMID:23290882

  4. Numerical and experimental analysis on load sharing & optimization of the joint parameters of polymer composite multi bolted joints

    NASA Astrophysics Data System (ADS)

    Latha Shankar, B.; Sudeep Kumar, T.; Shiva Shankar, G. S.

    2016-09-01

    In the present work, the bearing failure of composite bolted connections of composite laminates was analysed both experimentally and numerically. The glass fiber woven mat 600GSM/ epoxy composite laminates were prepared using wet-layup technique. The process parameters were taken care during preparation of laminates. Examination is done for various estimations of edge-to-hole diameter and width-to-hole diameter proportion. Stress is evaluated in laminates by utilizing Hart-Smith criteria. Ideal estimation of e/d proportion, d/w proportion is recommended for most extreme effectiveness. A numerical technique is utilized for the rough determination of a load shared by bolts in a numerous "bolted" joints loaded in tension were investigated experimentally and numerically. The effect of un-evenness in load shearing is suggested.

  5. The Relationship between MR Parameters and Biomechanical Quantities of Loaded Human Articular Cartilage in Osteoarthritis: An In-Vitro Study

    NASA Astrophysics Data System (ADS)

    Juráš, V.; Szomolányi, P.; Gäbler, S.; Frollo, I.; Trattnig, S.

    2009-01-01

    The aim of this study was to assess the changes in MRI parameters during applied load directly in MR scanner and correlate these changes with biomechanical parameters of human articular cartilage. Cartilage explants from patients who underwent total knee replacement were examined in the micro-imaging system in 3T scanner. Respective MRI parameters (T1 without- and T1 with contrast agent as a marker of proteoglycan content, T2 as a marker of collagen network anisotropy and ADC as a measure of diffusivity) were calculated in pre- and during compression state. Subsequently, these parameters were compared to the biomechanical properties of articular cartilage, instantaneous modulus (I), equilibrium modulus (Eq) and time of tissue relaxation (τ). Significant load-induced changes of T2 and ADC were recorded. High correlation between T1Gd and I (r = 0.6324), and between ADC and Eq (r = -0.4884) was found. Multi-parametric MRI may have great potential in analyzing static and dynamic biomechanical behavior of articular cartilage in early stages of osteoarthritis (OA).

  6. Parameters Affecting Loads on Buried Structures Subjected to Localized Blast Effects

    DTIC Science & Technology

    1992-04-01

    Structures Laboratory DEPARTMENT OF THE ARMY Waterways Experiment Station, Corps of Engineers 3909 Halls Ferry Road, Vicksburg, Mississippi 39180-6199...ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER US Army Engineer Waterways Experiment Station, Structures Laboratory, Technical Report SL-92-9...Loads on Buried Structures Subjected to Localized Blast Effects." These analyses were performed in the Structures Laboratory (SL), U.S. Army Engineer

  7. The Accuracy of Parameter Estimation in System Identification of Noisy Aircraft Load Measurement. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Kong, Jeffrey

    1994-01-01

    This thesis focuses on the subject of the accuracy of parameter estimation and system identification techniques. Motivated by a complicated load measurement from NASA Dryden Flight Research Center, advanced system identification techniques are needed. The objective of this problem is to accurately predict the load experienced by the aircraft wing structure during flight determined from a set of calibrated load and gage response relationship. We can then model the problem as a black box input-output system identification from which the system parameter has to be estimated. Traditional LS (Least Square) techniques and the issues of noisy data and model accuracy are addressed. A statistical bound reflecting the change in residual is derived in order to understand the effects of the perturbations on the data. Due to the intrinsic nature of the LS problem, LS solution faces the dilemma of the trade off between model accuracy and noise sensitivity. A method of conflicting performance indices is presented, thus allowing us to improve the noise sensitivity while at the same time configuring the degredation of the model accuracy. SVD techniques for data reduction are studied and the equivalence of the Correspondence Analysis (CA) and Total Least Squares Criteria are proved. We also looked at nonlinear LS problems with NASA F-111 data set as an example. Conventional methods are neither easily applicable nor suitable for the specific load problem since the exact model of the system is unknown. Neural Network (NN) does not require prior information on the model of the system. This robustness motivated us to apply the NN techniques on our load problem. Simulation results for the NN methods used in both the single load and the 'warning signal' problems are both useful and encouraging. The performance of the NN (for single load estimate) is better than the LS approach, whereas no conventional approach was tried for the 'warning signals' problems. The NN design methodology is also

  8. Using gait parameters to detect fatigue and responses to ice slurry during prolonged load carriage.

    PubMed

    Tay, Cheryl S; Lee, Jason K W; Teo, Ya S; Foo, Phildia Q Z; Tan, Pearl M S; Kong, Pui W

    2016-01-01

    This study examined (1) if changes in gait characteristics could indicate the exertional heat stress experienced during prolonged load carriage, and (2) if gait characteristics were responsive to a heat mitigation strategy. In an environmental chamber replicating tropical climatic conditions (ambient temperature 32°C, 70% relative humidity), 16 males aged 21.8 (1.2) years performed two trials of a work-rest cycle protocol consisting two bouts of 4-km treadmill walks with 30-kg load at 5.3km/h separated by a 15-min rest period. Ice slurry (ICE) or room temperature water (29°C) as a control (CON) was provided in 200-ml aliquots. The fluids were given 10min before the start, at the 15(th) and 30(th) min of each work cycle, and during each rest period. Spatio-temporal gait characteristics were obtained at the start and end of each work-rest cycle using a floor-based photocell system (OptoGait) and a high-speed video camera at 120Hz. Repeated-measure analysis of variance (trial×time) showed that with time, step width decreased (p=.024) while percent crossover steps increased (p=.008) from the 40(th) min onwards. Reduced stance time variability (-11.1%, p=.029) step width variability (-8.2%, p=.001), and percent crossover step (-18.5%, p=.010) were observed in ICE compared with CON. No differences in step length and most temporal variables were found. In conclusion, changes in frontal plane gait characteristics may indicate exertional heat stress during prolonged load carriage, and some of these changes may be mitigated with ice slurry ingestion.

  9. Changes in rabbit jaw-muscle activity parameters in response to reduced masticatory load.

    PubMed

    Grünheid, T; Brugman, P; Zentner, A; Langenbach, G E J

    2010-03-01

    Mechanical food properties influence the neuromuscular activity of jaw-closing muscles during mastication. It is, however, unknown how the activity profiles of the jaw muscles are influenced by long-term alterations in masticatory load. In order to elucidate the effect of reduced masticatory load on the daily habitual activity profiles of three functionally different jaw muscles, the electromyograms of the masseter, temporalis and digastric muscles were recorded telemetrically in 16 male rabbits between seven and 20 weeks of age. Starting at eight weeks of age the experimental animals were fed significantly softer pellets than the control animals. Daily muscle activity was quantified by the relative duration of muscle use (duty time), burst number and burst length in relation to multiple activity levels. The daily duty time and burst number of the masseter muscle were significantly lower in the experimental group than in the control group at 5% and 10% of the maximum activity during the two weeks following the change in food hardness. By contrast, altered food hardness did not significantly influence the activity characteristics of the temporalis and digastric muscles. The findings suggest that a reduction in masticatory load decreases the neuromuscular activity of the jaw-closing muscles that are primarily responsible for force generation during mastication. This decrease is most pronounced in the weeks immediately following the change in food hardness and is limited to the activity levels that reflect muscle contractions during chewing. These findings support the conclusion that the masticatory system manifests few diet-specific long-term changes in the activity profiles of jaw muscles.

  10. Evaluating the effects of loading parameters on single-crystal slip in tantalum using molecular mechanics

    NASA Astrophysics Data System (ADS)

    Alleman, Coleman; Ghosh, Somnath; Luscher, D. J.; Bronkhorst, Curt A.

    2014-01-01

    This study is aimed at developing a physics-based crystal plasticity finite element model for body-centred cubic (BCC) metals, through the introduction of atomic-level deformation information from molecular dynamics (MD) investigations of dislocation motion at the onset of plastic flow. In this study, three critical variables governing crystal plasticity mediated by dislocation motion are considered. MD simulations are first performed across a range of finite temperatures up to 600K to quantify the temperature dependence of critical stress required for slip initiation. An important feature of slip in BCC metals is that it is not solely dependent on the Schmid law measure of resolved shear stress, commonly employed in crystal plasticity models. The configuration of a screw dislocation and its subsequent motion is studied under different load orientations to quantify these non-Schmid effects. Finally, the influence of strain rates on thermal activation is studied by inducing higher stresses during activation at higher applied strain rates. Functional dependence of the critical resolved shear stress on temperature, loading orientation and strain rate is determined from the MD simulation results. The functional forms are derived from the thermal activation mechanisms that govern the plastic behaviour and quantification of relevant deformation variables. The resulting physics-based rate-dependent crystal plasticity model is implemented in a crystal plasticity finite element code. Uniaxial simulations reveal orientation-dependent tension-compression asymmetry of yield that more accurately represents single-crystal experimental results than standard models.

  11. Practical implementation of the corrected force analysis technique to identify the structural parameter and load distributions

    NASA Astrophysics Data System (ADS)

    Leclère, Quentin; Ablitzer, Frédéric; Pézerat, Charles

    2015-09-01

    The paper aims to combine two objectives of the Force Analysis Technique (FAT): vibration source identification and material characterization from the same set of measurement. Initially, the FAT was developed for external load location and identification. It consists in injecting measured vibration displacements in the discretized equation of motion. Two developments exist: FAT and CFAT (Corrected Force Analysis Technique) where two finite difference schemes are used. Recently, the FAT was adapted for the identification of elastic and damping properties in a structure. The principal interests are that the identification is local and allows mapping of material characteristics, the identification can be made at all frequencies, especially in medium and high frequency domains. The paper recalls the development of FAT and CFAT on beams and plates and how it can be possible to extract material characteristics in areas where no external loads are applied. Experimental validations are shown on an aluminum plate with arbitrary boundary conditions, excited by a point force and where a piece of foam is glued on a sub-surface of the plate. Contactless measurements were made using a scanning laser vibrometer. The results of FAT and CFAT are compared and discussed for material property identifications in the regions with and without foam. The excitation force identification is finally made by using the identified material properties. CFAT gives excellent results comparable to a direct measurement obtained by a piezoelectric sensor. The relevance of the corrected scheme is then underlined for both source identification and material characterization from the same measurements.

  12. RANS computations for identification of 1-D cavitation model parameters: application to full load cavitation vortex rope

    NASA Astrophysics Data System (ADS)

    Alligné, S.; Decaix, J.; Müller, A.; Nicolet, C.; Avellan, F.; Münch, C.

    2016-11-01

    Due to the massive penetration of alternative renewable energies, hydropower is a key energy conversion technology for stabilizing the electrical power network by using hydraulic machines at off design operating conditions. At full load, the axisymmetric cavitation vortex rope developing in Francis turbines acts as an internal source of energy, leading to an instability commonly referred to as selfexcited surge. 1-D models are developed to predict this phenomenon and to define the range of safe operating points for a hydropower plant. These models involve several parameters that have to be calibrated using experimental and numerical data. The present work aims to identify these parameters with URANS computations with a particular focus on the fluid damping rising when the cavitation volume oscillates. Two test cases have been investigated: a cavitation flow in a Venturi geometry without inlet swirl and a reduced scale model of a Francis turbine operating at full load conditions. The cavitation volume oscillation is forced by imposing an unsteady outlet pressure conditions. By varying the frequency of the outlet pressure, the resonance frequency is determined. Then, the pressure amplitude and the resonance frequency are used as two objectives functions for the optimization process aiming to derive the 1-D model parameters.

  13. Prediction of tip vortex self-induced motion parameters in terms of rotor blade loading

    NASA Technical Reports Server (NTRS)

    Bliss, Donald B.

    1987-01-01

    The self-induced motion of curved vortex filaments at the tip of a helicopter rotor blade is investigated analytically. The derivation of a method for inviscid roll-up (IRU) is presented in detail, with attention to the cutoff-distance reformulation of the problem, a control-volume analysis of the self-induction properties of the vortex core, the adaptation of the roll-up method of Betz (1932) to IRU in three dimensions, the treatment of linear and elliptic loading, vortices with turbulent central cores, and the effect of cutoff distance on helicopter free-wake computations. Numerical results showing the significant effect of core properties on the geometry of a rotor wake in hover are presented in graphs and briefly characterized.

  14. Knee Power Is an Important Parameter in Understanding Medial Knee Joint Load in Knee Osteoarthritis

    PubMed Central

    Calder, Kristina M; Acker, Stacey M; Arora, Neha; Beattie, Karen A; Callaghan, Jack P; Adachi, Jonathan D; Maly, Monica R

    2014-01-01

    Objective To determine the extent to which knee extensor strength and power explain variance in knee adduction moment (KAM) peak and impulse in clinical knee osteoarthritis (OA). Methods Fifty-three adults (mean ± SD age 61.6 ± 6.3 years, 11 men) with clinical knee OA participated. The KAM waveform was calculated from motion and force data and ensemble averaged from 5 walking trials. The KAM peak was normalized to body mass (Nm/kg). The mean KAM impulse reflected the mean total medial knee load during stride (Nm × seconds). For strength, the maximum knee extensor moment attained from maximal voluntary isometric contractions (MVIC) was normalized to body mass (Nm/kg). For power, the maximum knee extensor power during isotonic contractions, with the resistance set at 25% of MVIC, was normalized to body mass (W/kg). Covariates included age, sex, knee pain on the Knee Injury and Osteoarthritis Outcome Score, gait speed, and body mass index (BMI). Relationships of the KAM peak and impulse with strength and power were examined using sequential stepwise forward linear regressions. Results Covariates did not explain variance in the KAM peak. While extensor strength did not, peak knee extensor power explained 8% of the variance in the KAM peak (P = 0.02). Sex and BMI explained 24% of the variance in the KAM impulse (P < 0.05). Sex, BMI, and knee extensor power explained 31% of the variance in the KAM impulse (P = 0.02), with power contributing 7% (P < 0.05). Conclusion Knee extensor power was more important than isometric knee strength in understanding medial knee loads during gait. PMID:24920175

  15. Monitoring internal load parameters during competitive synchronized swimming duet routines in elite athletes.

    PubMed

    Rodríguez-Zamora, Lara; Iglesias, Xavier; Barrero, Anna; Torres, Lorena; Chaverri, Diego; Rodríguez, Ferran A

    2014-03-01

    The aim of the study is to compare the heart rate (HR) and rate of perceived exertion (RPE) responses as internal load indicators while performing duet routines during training and competition, both in the technical and free programs of synchronized swimming (SS). Participants were 10 SS Olympic medalists (age, 17.4 ± 3.0 years; height, 164.0 ± 6.1 cm; body mass, 52.0 ± 6.4 kg; training, 36.3 ± 6.2 h·wk; experience, 9.2 ± 2.6 years). They were monitored while performing the same technical duet or free duet, during a training session (T) and during an official competition (C). Heart rate was continuously monitored. Rate of perceived exertion was assessed using the Borg CR10 scale. Heart rate responses during T and C were almost identical: pre-exercise mean HR (b·min) was 130.5 ± 13.9 (T) and 133.6 ± 7.7 (C) and quickly increased yielding mean peak values of 184.8 ± 5.8 (T) and 184.8 ± 6.6 (C), with interspersed bradycardic events down to 86.6 ± 4 (T) and 86.3 ± 5 (C). Routines were perceived as "hard" to "extremely hard" by the swimmers in both conditions, and mean RPE scores (0-10+) were equally high during C (7.9 ± 1.2) and T (7.5 ± 1.2) (p = 0.223). Rate of perceived exertion inversely correlated with minimum (R = -0.545; p = 0.008) and mean HR (R = -0.452; p = 0.026) and positively correlated with HRrange (R = 0.520; p = 0.011). The internal load imposed by SS duets performed during training is virtually identical to that elicited in a real competitive situation. Therefore, practicing competitive routines is suitable for developing and maintaining the cardiovascular fitness that is needed for specific conditioning in elite synchronized swimmers, with the added value of favoring exercise automaticity, interindividual coordination, and artistic expression simultaneously.

  16. Parameter analysis of PEM fuel cell hysteresis effects for transient load use

    NASA Astrophysics Data System (ADS)

    Talj, R.; Azib, T.; Béthoux, O.; Remy, G.; Marchand, C.; Berthelot, E.

    2011-05-01

    This paper focuses on the hysteresis effect of the polarization characteristics of a polymer electrolyte membrane fuel cell (PEMFC), mainly due to the compressor-air supply system dynamics. Indeed in PEMFC/ultracapacitor hybrid vehicles, fuel cells can be used to supply the low frequencies of the power demand only. First, the different parts of a FC system are described and modeled in order to analyze the transient stack performance decrease and to identify its main influential factors for automotive applications. Then, apart from humidity and temperature variations, each phenomenon is dynamically described, leading to a complete mathematical model based on macroscopic component parameters. Thus, an analytical model based on this set of equations enables us to draw the static voltage versus current FC characteristics. Furthermore, the hysteresis effect on the V-I curve, which still occurs during low dynamic responses, is shown while temperature and humidity are kept constant. Finally, dynamic responses of the Ballard PEMFC Nexa 1200 W generator are analyzed, and detailed experimentation and simulation are carried out for a large magnitude sinusoidal waveform at different frequencies.

  17. Working memory load-related electroencephalographic parameters can differentiate progressive from stable mild cognitive impairment.

    PubMed

    Missonnier, P; Deiber, M-P; Gold, G; Herrmann, F R; Millet, P; Michon, A; Fazio-Costa, L; Ibañez, V; Giannakopoulos, P

    2007-12-05

    Recent studies described several changes of endogenous event-related potentials (ERP) and brain rhythm synchronization during memory activation in patients with Alzheimer's disease (AD). To examine whether memory-related EEG parameters may predict cognitive decline in mild cognitive impairment (MCI), we assessed P200 and N200 latencies as well as beta event-related synchronization (ERS) in 16 elderly controls (EC), 29 MCI cases and 10 patients with AD during the successful performance of a pure attentional detection task as compared with a highly working memory demanding two-back task. At 1 year follow-up, 16 MCI patients showed progressive cognitive decline (PMCI) and 13 remained stable (SMCI). Both P200 and N200 latencies in the two-back task were longer in PMCI and AD cases compared with EC and SMCI cases. During the interval 1000 ms to 1700 ms after stimulus, beta ERS at parietal electrodes was of lower amplitude in PMCI and AD compared with EC and SMCI cases. Univariate models showed that P200, N200 and log% beta values were significantly related to the SMCI/PMCI distinction with areas under the receiver operating characteristic curve of 0.93, 0.78 and 0.72, respectively. The combination of all three EEG hallmarks was the stronger predictor of MCI deterioration with 90% of correctly classified MCI cases. Our data reveal that PMCI and clinically overt AD share the same pattern of working memory-related EEG activation characterized by increased P200-N200 latencies and decreased beta ERS. They also show that P200 latency during the two-back task may be a simple and promising EEG marker of rapid cognitive decline in MCI.

  18. HIRREM™: a noninvasive, allostatic methodology for relaxation and auto-calibration of neural oscillations

    PubMed Central

    Gerdes, Lee; Gerdes, Peter; Lee, Sung W; H Tegeler, Charles

    2013-01-01

    Disturbances of neural oscillation patterns have been reported with many disease states. We introduce methodology for HIRREM™ (high-resolution, relational, resonance-based electroencephalic mirroring), also known as Brainwave Optimization™, a noninvasive technology to facilitate relaxation and auto-calibration of neural oscillations. HIRREM is a precision-guided technology for allostatic therapeutics, intended to help the brain calibrate its own functional set points to optimize fitness. HIRREM technology collects electroencephalic data through two-channel recordings and delivers a series of audible musical tones in near real time. Choices of tone pitch and timing are made by mathematical algorithms, principally informed by the dominant frequency in successive instants of time, to permit resonance between neural oscillatory frequencies and the musical tones. Relaxation of neural oscillations through HIRREM appears to permit auto-calibration toward greater hemispheric symmetry and more optimized proportionation of regional spectral power. To illustrate an application of HIRREM, we present data from a randomized clinical trial of HIRREM as an intervention for insomnia (n = 19). On average, there was reduction of right-dominant temporal lobe high-frequency (23–36 Hz) EEG asymmetry over the course of eight successive HIRREM sessions. There was a trend for correlation between reduction of right temporal lobe dominance and magnitude of insomnia symptom reduction. Disturbances of neural oscillation have implications for both neuropsychiatric health and downstream peripheral (somatic) physiology. The possibility of noninvasive optimization for neural oscillatory set points through HIRREM suggests potentially multitudinous roles for this technology. Research is currently ongoing to further explore its potential applications and mechanisms of action. PMID:23532171

  19. Characterization of load bearing metrological parameters in reptilian exuviae in comparison to precision-finished cylinder liner surfaces

    NASA Astrophysics Data System (ADS)

    Abdel-Aal, H. A.; El Mansori, M.

    2014-10-01

    Design of precise functional surfaces is essential for many future applications. In the technological realm, the accumulated experience with construction of such surfaces is not sufficient. Nature provides many examples of dynamic surfaces worthy of study and adoption, at least in concept, within human engineering. This work probes the load-bearing metrological features of the ventral skin in snakes. We examine the structure of two snake species that mainly move by rectilinear locomotion. These are Python regius (Pythonidae) and Bitis gabonica (Vipridae). To this end, we focus on the load-bearing characteristics of the ventral skin surface (i.e., the Sk family of parameters). Therefore, detailed comparison is drawn between the metrological structure of the reptilian surfaces and two sets of technological data. The first set pertains to an actual commercial cylinder liner, whereas the second set is a summary of recommended surface finish metrological values for several commercial cylinder liner manufacturers. The results highlight several similarities between the two types of surfaces. In particular, it is shown that there is a striking correspondence between the sense of texture morphology within both surfaces (although their construction evolved along entirely different paths). It is also shown that reptilian surfaces manifest a high degree of specialization with respect to habitat constraints on wear resistance and adhesive effects. In particular, their surface displays a high degree of pre-conditioning to functional requirements, which eliminates the need for a running-in period.

  20. Scaling up watershed model parameters: flow and load simulations of the Edisto River Basin, South Carolina, 2007-09

    USGS Publications Warehouse

    Feaster, Toby D.; Benedict, Stephen T.; Clark, Jimmy M.; Bradley, Paul M.; Conrads, Paul A.

    2014-01-01

    As part of an ongoing effort by the U.S. Geological Survey to expand the understanding of relations among hydrologic, geochemical, and ecological processes that affect fish-tissue mercury concentrations within the Edisto River Basin, analyses and simulations of the hydrology of the Edisto River Basin were made using the topography-based hydrological model (TOPMODEL). A primary focus of the investigation was to assess the potential for scaling up a previous application of TOPMODEL for the McTier Creek watershed, which is a small headwater catchment to the Edisto River Basin. Scaling up was done in a step-wise manner, beginning with applying the calibration parameters, meteorological data, and topographic-wetness-index data from the McTier Creek TOPMODEL to the Edisto River TOPMODEL. Additional changes were made for subsequent simulations, culminating in the best simulation, which included meteorological and topographic wetness index data from the Edisto River Basin and updated calibration parameters for some of the TOPMODEL calibration parameters. The scaling-up process resulted in nine simulations being made. Simulation 7 best matched the streamflows at station 02175000, Edisto River near Givhans, SC, which was the downstream limit for the TOPMODEL setup, and was obtained by adjusting the scaling factor, including streamflow routing, and using NEXRAD precipitation data for the Edisto River Basin. The Nash-Sutcliffe coefficient of model-fit efficiency and Pearson’s correlation coefficient for simulation 7 were 0.78 and 0.89, respectively. Comparison of goodness-of-fit statistics between measured and simulated daily mean streamflow for the McTier Creek and Edisto River models showed that with calibration, the Edisto River TOPMODEL produced slightly better results than the McTier Creek model, despite the substantial difference in the drainage-area size at the outlet locations for the two models (30.7 and 2,725 square miles, respectively). Along with the TOPMODEL

  1. Effect of the Initial Load Parameters on the K-shell Output of Al Planar Wire Arrays Operating in the Microsecond Implosion Regime

    SciTech Connect

    Shishlov, A.; Chaikovsky, S.; Fedunin, A.; Fursov, F.; Kokshenev, V.; Kurmaev, N.; Labetsky, A.; Oreshkin, V.; Rousskikh, A.; Labetskaya, N.

    2009-01-21

    A set of microsecond implosion experiments was carried on the GIT-12 generator to study the radiative performance of Al planar wire arrays. The load parameters such as a wire diameter, a gap between the wires, the number of wires, and the total planar wire mass and width were varied during the experiments, however the implosion time and the peak implosion current were almost the same for all load configurations. This ensured equal energy deposition to the plasma due to kinetic mechanisms for all load configurations. Two implosion regimes with the implosion times of 1050 ns and 850 ns were investigated. The experimental data on the K-shell radiation yield and power at varying load parameters are presented.

  2. Application of quality by design approach to optimize process and formulation parameters of rizatriptan loaded chitosan nanoparticles.

    PubMed

    Shirsat, Ajinath Eknath; Chitlange, Sohan S

    2015-01-01

    The purpose of present study was to optimize rizatriptan (RZT) chitosan (CS) nanoparticles using ionic gelation method by application of quality by design (QbD) approach. Based on risk assessment, effect of three variables, that is CS %, tripolyphosphate % and stirring speed were studied on critical quality attributes (CQAs); particle size and entrapment efficiency. Central composite design (CCD) was implemented for design of experimentation with 20 runs. RZT CS nanoparticles were characterized for particle size, polydispersity index, entrapment efficiency, in-vitro release study, differential scanning calorimetric, X-ray diffraction, scanning electron microscopy (SEM). Based on QbD approach, design space (DS) was optimized with a combination of selected variables with entrapment efficiency > 50% w/w and a particle size between 400 and 600 nm. Validation of model was performed with 3 representative formulations from DS for which standard error of - 0.70-3.29 was observed between experimental and predicted values. In-vitro drug release followed initial burst release 20.26 ± 2.34% in 3-4 h with sustained drug release of 98.43 ± 2.45% in 60 h. Lower magnitude of standard error for CQAs confirms the validation of selected CCD model for optimization of RZT CS nanoparticles. In-vitro drug release followed dual mechanism via, diffusion and polymer erosion. RZT CS nanoparticles were prepared successfully using QbD approach with the understanding of the high risk process and formulation parameters involved and optimized DS with a multifactorial combination of critical parameters to obtain predetermined RZT loaded CS nanoparticle specifications.

  3. Application of quality by design approach to optimize process and formulation parameters of rizatriptan loaded chitosan nanoparticles

    PubMed Central

    Shirsat, Ajinath Eknath; Chitlange, Sohan S.

    2015-01-01

    The purpose of present study was to optimize rizatriptan (RZT) chitosan (CS) nanoparticles using ionic gelation method by application of quality by design (QbD) approach. Based on risk assessment, effect of three variables, that is CS %, tripolyphosphate % and stirring speed were studied on critical quality attributes (CQAs); particle size and entrapment efficiency. Central composite design (CCD) was implemented for design of experimentation with 20 runs. RZT CS nanoparticles were characterized for particle size, polydispersity index, entrapment efficiency, in-vitro release study, differential scanning calorimetric, X-ray diffraction, scanning electron microscopy (SEM). Based on QbD approach, design space (DS) was optimized with a combination of selected variables with entrapment efficiency > 50% w/w and a particle size between 400 and 600 nm. Validation of model was performed with 3 representative formulations from DS for which standard error of − 0.70–3.29 was observed between experimental and predicted values. In-vitro drug release followed initial burst release 20.26 ± 2.34% in 3–4 h with sustained drug release of 98.43 ± 2.45% in 60 h. Lower magnitude of standard error for CQAs confirms the validation of selected CCD model for optimization of RZT CS nanoparticles. In-vitro drug release followed dual mechanism via, diffusion and polymer erosion. RZT CS nanoparticles were prepared successfully using QbD approach with the understanding of the high risk process and formulation parameters involved and optimized DS with a multifactorial combination of critical parameters to obtain predetermined RZT loaded CS nanoparticle specifications. PMID:26317071

  4. In vivo photodynamic activity of photosensitizer-loaded nanoparticles: formulation properties, administration parameters and biological issues involved in PDT outcome.

    PubMed

    Vargas, Angelica; Eid, Michael; Fanchaouy, Mohammed; Gurny, Robert; Delie, Florence

    2008-05-01

    Encapsulation of hydrophobic photosensitizers (PS) into polymeric nanoparticles (NP) has proven to be an effective alternative to organic solvents for their formulation. As NP size controls NP passage through endothelial barriers, it is a key parameter for achieving passive targeting of cancer tissues and choroidal neovascularization, secondary to age-related macular degeneration, the main applications of photodynamic therapy. In the present study, a hydrophobic PS, the meso-tetra(p-hydroxyphenyl)porphyrin, was encapsulated into biodegradable NP made of poly(D,L-lactide-co-glycolide) 50:50 via an emulsification-diffusion technique. NP batches having mean diameters of 117, 285, and 593 nm were obtained with narrow size distribution. Using the chorioallantoic membrane (CAM) of the developing chick embryo, it was demonstrated that the increase in the NP size decreased photodynamic activity in vivo. The activity of PS-loaded NP was not influenced by the volume of injection and was kept intact at least 6h after NP reconstitution. Investigation of NP circulation after IV administration by fluorescence measurements revealed that 117 nm NP reached Tmax earlier than larger NP. Confocal imaging of CAM vessels demonstrated PS uptake by endothelial cells after NP administration. It was concluded that NP size controls the photodynamic activity of the encapsulated PS.

  5. Effect of WOW process parameters on morphology and burst release of FITC-dextran loaded PLGA microspheres.

    PubMed

    Mao, Shirui; Xu, Jing; Cai, Cuifang; Germershaus, Oliver; Schaper, Andreas; Kissel, Thomas

    2007-04-04

    Using fluorescein isothiocyanate labeled dextran (FITC-dextran 40, FD40) as a hydrophilic model compound, microspheres were prepared by a WOW double emulsion technique. Influence of process parameters on microsphere morphology and burst release of FD40 from PLGA microspheres was studied. Internal morphology of microspheres was investigated by stereological method via cryo-cutting technique and scanning electron microscopy (SEM). Drug distribution in microspheres was observed with confocal laser scanning microscopy (CLSM). Polymer nature (RG503 and RG503H) had significant influence on the micro-morphology of microspheres. Increase in continuous water phase volume (W2) led to increased surface porosity but decreased internal porosity. By increasing PVA concentration in the continuous phase from 0.1 to 1%, particle size changed marginally but burst release decreased from 12.2 to 5.9%. Internal porosity of microspheres decreased considerably with increasing polymer concentration. Increase in homogenization speed during the primary emulsion preparation led to decreased internal porosity. Burst release decreased with increasing drug loading but increased with drug molecular weight. Drug distribution in microspheres depended on preparation method. The porosity of microspheres decreased with time in the diffusion stage, but internal morphology had no influence on the release behavior in the bioerosion stage. In summary, surface porosity and internal morphology play a significant role in the release of hydrophilic macromolecules from biodegradable microspheres in the initial release phase characterized by pore diffusion.

  6. Selective ensemble modeling load parameters of ball mill based on multi-scale frequency spectral features and sphere criterion

    NASA Astrophysics Data System (ADS)

    Tang, Jian; Yu, Wen; Chai, Tianyou; Liu, Zhuo; Zhou, Xiaojie

    2016-01-01

    It is difficult to model multi-frequency signal, such as mechanical vibration and acoustic signals of wet ball mill in the mineral grinding process. In this paper, these signals are decomposed into multi-scale intrinsic mode functions (IMFs) by the empirical mode decomposition (EMD) technique. A new adaptive multi-scale spectral features selection approach based on sphere criterion (SC) is applied to these IMFs frequency spectra. The candidate sub-models are constructed by the partial least squares (PLS) with the selected features. Finally, the branch and bound based selective ensemble (BBSEN) algorithm is applied to select and combine these ensemble sub-models. This method can be easily extended to regression and classification problems with multi-time scale signal. We successfully apply this approach to a laboratory-scale ball mill. The shell vibration and acoustic signals are used to model mill load parameters. The experimental results demonstrate that this novel approach is more effective than the other modeling methods based on multi-scale frequency spectral features.

  7. Cumulative Socioeconomic Status Risk, Allostatic Load, and Adjustment: A Prospective Latent Profile Analysis with Contextual and Genetic Protective Factors

    ERIC Educational Resources Information Center

    Brody, Gene H.; Yu, Tianyi; Chen, Yi-Fu; Kogan, Steven M.; Evans, Gary W.; Beach, Steven R. H.; Windle, Michael; Simons, Ronald L.; Gerrard, Meg; Gibbons, Frederick X.; Philibert, Robert A.

    2013-01-01

    The health disparities literature has identified a common pattern among middle-aged African Americans that includes high rates of chronic disease along with low rates of psychiatric disorders despite exposure to high levels of cumulative socioeconomic status (SES) risk. The current study was designed to test hypotheses about the developmental…

  8. Characterization of Biosensors Based on Recombinant Glutamate Oxidase: Comparison of Crosslinking Agents in Terms of Enzyme Loading and Efficiency Parameters

    PubMed Central

    Ford, Rochelle; Quinn, Susan J.; O’Neill, Robert D.

    2016-01-01

    Amperometric l-glutamate (Glu) biosensors, based on both wild-type and a recombinant form of l-glutamate oxidase (GluOx), were designed and characterized in terms of enzyme-kinetic, sensitivity and stability parameters in attempts to fabricate a real-time Glu monitoring device suitable for future long-term detection of this amino acid in biological and other complex media. A comparison of the enzyme from these two sources showed that they were similar in terms of biosensor performance. Optimization of the loading of the polycationic stabilization agent, polyethyleneimine (PEI), was established before investigating a range of crosslinking agents under different conditions: glutaraldehyde (GA), polyethylene glycol (PEG), and polyethylene glycol diglycidyl ether (PEGDE). Whereas PEI-free biosensor designs lost most of their meager Glu sensitivity after one or two days, configurations with a 2:5 ratio of dip-evaporation applications of PEI(1%):GluOx(400 U/mL) displayed a 20-fold increase in their initial sensitivity, and a decay half-life extended to 10 days. All the crosslinkers studied had no effect on initial Glu sensitivity, but enhanced biosensor stability, provided the crosslinking procedure was carried out under well-defined conditions. The resulting biosensor design based on the recombinant enzyme deposited on a permselective layer of poly-(ortho-phenylenediamine), PoPD/PEI2/GluOx5/PEGDE, displayed good sensitivity (LOD < 0.2 μM), response time (t90% < 1 s) and stability over a 90-day period, making it an attractive candidate for future long-term monitoring of Glu concentration dynamics in complex media. PMID:27669257

  9. Parameter Estimation of Actuators for Benchmark Active Control Technology (BACT) Wind Tunnel Model with Analysis of Wear and Aerodynamic Loading Effects

    NASA Technical Reports Server (NTRS)

    Waszak, Martin R.; Fung, Jimmy

    1998-01-01

    This report describes the development of transfer function models for the trailing-edge and upper and lower spoiler actuators of the Benchmark Active Control Technology (BACT) wind tunnel model for application to control system analysis and design. A simple nonlinear least-squares parameter estimation approach is applied to determine transfer function parameters from frequency response data. Unconstrained quasi-Newton minimization of weighted frequency response error was employed to estimate the transfer function parameters. An analysis of the behavior of the actuators over time to assess the effects of wear and aerodynamic load by using the transfer function models is also presented. The frequency responses indicate consistent actuator behavior throughout the wind tunnel test and only slight degradation in effectiveness due to aerodynamic hinge loading. The resulting actuator models have been used in design, analysis, and simulation of controllers for the BACT to successfully suppress flutter over a wide range of conditions.

  10. Influence of loading cycle profile and frequency on a biomechanical parameter of a model of a balloon kyphoplasty-augmented lumbar spine segment: a finite element analysis study.

    PubMed

    Li, Yuan; Lewis, Gladius

    2010-01-01

    For patients who are suffering debilitating and persistent pain due to vertebral compression fracture(s) and for whom conservative therapies have not provided relief, balloon kyphoplasty (BKP) is used as a surgical option. There are only a very few literature reports on the use of the finite element analysis (FEA) method to obtain biomechanical parameters of models of spine segments that include BKP augmentation at a given level. In each of these studies, the applied loading used was quasi-static. During normal activities of daily living, the patient's spine would be subject to dynamically-applied loading. Thus, the question of the influence of the characteristics of a dynamically-applied loading cycle on biomechanical parameters of a spine that includes BKP-augmented segment(s) is germane; however, a study of this issue is lacking. We investigated this issue in the present FEA work, with the spine segment model being the L1-L3 motion segment units (MSUs) (a segment that is commonly augmented using BKP) and prophylactic BKP simulated at L2. The dynamic load was the compressive load-versus-time cycle to which the L3-L4 MSU is subjected during gait. Four cases of the cycle were considered, corresponding to slow-, normal-, fast- and very fast-paced gait. The loading cycle was applied to the superior surface of L1 while the inferior surface of L3 was fully constrained. It was found that (1) the global mean von Mises stress during the loading cycle (σVMG), in each tissue in the model increased in going from a slow-paced gait cycle to a very fast-paced gait cycle; and (2) for the slow-paced gait cycle, with increase in frequency of the cycle, f (1 ≤ f ≤ 3 Hz), σVMG in each of these tissues increased. Potential uses of the present findings are identified.

  11. Assessment of the effect of anthropometric data on the alterations of cardiovascular parameters in Lithuanian elite male basketball players during physical load.

    PubMed

    Žumbakytė-Šermukšnienė, Renata; Kajėnienė, Alma; Berškienė, Kristina; Daunoravičienė, Algė; Sederevičiūtė-Kandratavičienė, Rasa

    2012-01-01

    OBJECTIVES. The aim of the study was to assess the effect of the anthropometric data of basketball players on the alterations of cardiovascular parameters during the physical load applying the model of integrated evaluation. MATERIAL AND METHODS. The research sample consisted of 113 healthy Caucasian male basketball players, candidates of the Lithuanian National men's basketball teams. Basketball players were divided into 2 groups: 69 taller and heavier male basketball players (with a higher percentage of body fat) (TMB) and 44 shorter and less heavy male basketball players (with a lower percentage of body fat) (SMB). The amount of fat, expressed in percentage, was measured using the body composition analyzer TBF-300. "Kaunas-Load," a computerized ECG analysis system, was used to evaluate the functional condition of the cardiovascular system during the load. RESULTS. The TMB group had a lower heart rate during the warming-up phase and the steady state of the load as compared with the SMB group (P<0.05). The JT interval in the TMB group was greater during the warming-up and the steady state as compared with the SMB group (P<0.05). The JT/RR ratio index in the TMB group was found to be lower in the warming-up phase and in the steady state compared with the respective parameter in the SMB group (P<0.05). CONCLUSIONS. The cardiovascular system of taller and heavier male basketball players with a greater relative amount of body fat functioned more economically.

  12. Improving the accuracy of derivation of the Williams’ series parameters under mixed (I+II) mode loading by compensation of measurement bias in the stress field components data

    NASA Astrophysics Data System (ADS)

    Lychak, Oleh V.; Holyns'kiy, Ivan S.

    2016-12-01

    A new method for compensation of bias in the stress field components measurement data used for Williams’ series parameters derivation was presented. Essential increase of accuracy of derivation of SIF-related leading terms in series under mixed (I+II) mode loading was demonstrated. It was shown that a relatively low value of bias in the stress field components data error could result in the essential deviation of the values of derived Williams’ coefficients and the crack tip coordinates.

  13. Modal parameter identification of a compression-loaded CFRP stiffened plate and correlation with its buckling behaviour

    NASA Astrophysics Data System (ADS)

    Chaves-Vargas, M.; Dafnis, A.; Reimerdes, H.-G.; Schröder, K.-U.

    2015-10-01

    In order to study the dynamic response and the buckling behaviour of several load-carrying structural components of civil aircraft when subjected to transient load scenarios such as gusts or a landing impact, a generic mid-size aircraft is defined within the European research project DAEDALOS. From this aircraft, several sections or panels in different regions such as wing, vertical tailplane and fuselage are defined. The stiffened carbon-fibre-reinforced plastic (CFRP) plate investigated within the present work represents a simplified version of the wing panel selected from the generic aircraft. As part of the current work, the buckling behaviour and the modal properties of the stiffened plate under the effect of a static in-plane compression load are studied. This is accomplished by means of a test series including quasi-static buckling tests and an experimental modal analysis (EMA). One of the key objectives pursued is the correlation of the modal properties to the buckling behaviour by studying the relationship between the natural frequencies of the stiffened plate and its corresponding buckling load. The experimental work is verified by a finite element analysis.

  14. Combined use of VUV and UVC photoreactors for the treatment of hospital laundry wastewaters: Reduction of load parameters, detoxification and life cycle assessment of different configurations.

    PubMed

    de Oliveira Schwaickhardt, Rômulo; Machado, Ênio Leandro; Lutterbeck, Carlos Alexandre

    2017-07-15

    The present research investigated the treatment of hospital laundry wastewaters by the combined use of photochemical VUV and UVC reactors. Seven different configurations were tested and the performances of each of them were evaluated based on the removal of the load parameters, detoxification and life cycle assessment (LCA). The characterization of studied wastewaters included analysis of the following parameters: COD, BOD5, TKN, total P, pH, turbidity and conductivity. Acute ecotoxicity was evaluated using Daphnia magna. Ultraviolet-Visible (UV-Vis) spectroscopy was performed to determine the organic fraction and chromatography coupled to the mass spectrometer (GC-MS) was used for the qualitative characterization of priority pollutants. Characterization parameters showed the presence of drugs like lidocaine and dipyrone and a high organic load with a poor biodegradability. Wastewaters presented an extreme acute toxicity against D. magna (EC50 6.7%). The ozonation process (mainly generated by the VUV reactor) obtained the best results concerning the ratio between the consumed energy and the removed COD and the UVC process presented the lowest environmental impacts for the characterization and normalization parameters of the LCA. Normalization revealed that the highest environmental burdens were associated with human toxicity, ecotoxicity and eutrophication of surface waters as well as to the use of non-renewable resources. VUV/UVC/O3 process presented the best results considering detoxification (EC50 100%).

  15. Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms

    NASA Astrophysics Data System (ADS)

    Katiyatiya, C. L. F.; Muchenje, V.; Mushunje, A.

    2014-08-01

    Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals (P < 0.05). Zazulwana cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms (P < 0.05). High tick loads were recorded for cows with long hairs. Hair lengths were longest during the winter season in the coastal areas of Zazulwana and Honeydale (P < 0.05). White and brown-white patched cows had significantly longer (P < 0.05) hair strands than those having a combination of red, black and white colour. Cortisol and THI were significantly lower (P < 0.05) in summer season. Red blood cells, haematoglobin, haematocrit, mean cell volumes, white blood cells, neutrophils, lymphocytes, eosinophils and basophils were significantly different (P < 0.05) as some associated with age across all seasons and correlated to THI. It was concluded that the location, coat colour and season had effects on hair length, cortisol levels, THI, HP and tick loads on different body parts and heat stress in Nguni cows.

  16. Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms

    NASA Astrophysics Data System (ADS)

    Katiyatiya, C. L. F.; Muchenje, V.; Mushunje, A.

    2015-06-01

    Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals ( P < 0.05). Zazulwana cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms ( P < 0.05). High tick loads were recorded for cows with long hairs. Hair lengths were longest during the winter season in the coastal areas of Zazulwana and Honeydale ( P < 0.05). White and brown-white patched cows had significantly longer ( P < 0.05) hair strands than those having a combination of red, black and white colour. Cortisol and THI were significantly lower ( P < 0.05) in summer season. Red blood cells, haematoglobin, haematocrit, mean cell volumes, white blood cells, neutrophils, lymphocytes, eosinophils and basophils were significantly different ( P < 0.05) as some associated with age across all seasons and correlated to THI. It was concluded that the location, coat colour and season had effects on hair length, cortisol levels, THI, HP and tick loads on different body parts and heat stress in Nguni cows.

  17. Effect of an allostatic modulator on stress blood indicators and meat quality of commercial young bulls in Mexico.

    PubMed

    Rubio Lozano, M S; Méndez Medina, R D; Reyes Mayorga, K; Rubio García, M E; Ovando, M A; Ngapo, T M; Galindo Maldonado, F A

    2015-07-01

    To assess the effect of an allostatic modulator (AM) on stress blood indicators and meat quality traits, the feed of 80 non-castrated 18-20 month-old bulls was supplemented with 10 g/day of an AM for 30 days before slaughter. Another 80 bulls served as control animals. The AM was comprised of ascorbic acid, acetoxybenzoic acid and sodium and potassium chloride. Blood samples were taken at slaughter for analyses of hematocrit value, erythrocyte and leukocyte counts, and glucose, lactate and cortisol concentrations. Post-mortem measures of meat color and pH were made at 24h and color, shear force and cooking loss on meat from 20 animals at 28 days. The AM supplementation resulted in lower hematocrit value, erythrocyte count and glucose level (P<0.05), higher a* (P<0.0001) and b* (P<0.0001) at 24h and lower b* (P<0.05) at 28 days. Thus AM treatment improved some stress blood indicators and meat color and therefore merits further investigation.

  18. Apparent Dependence of Rate- and State-Dependent Friction Parameters on Loading Velocity and Cumulative Displacement Inferred from Large-Scale Biaxial Friction Experiments

    NASA Astrophysics Data System (ADS)

    Urata, Yumi; Yamashita, Futoshi; Fukuyama, Eiichi; Noda, Hiroyuki; Mizoguchi, Kazuo

    2016-11-01

    We investigated the constitutive parameters in the rate- and state-dependent friction (RSF) law by conducting numerical simulations, using the friction data from large-scale biaxial rock friction experiments for Indian metagabbro. The sliding surface area was 1.5 m long and 0.5 m wide, slid for 400 s under a normal stress of 1.33 MPa at a loading velocity of either 0.1 or 1.0 mm/s. During the experiments, many stick-slips were observed and those features were as follows. (1) The friction drop and recurrence time of the stick-slip events increased with cumulative slip displacement in an experiment before which the gouges on the surface were removed, but they became almost constant throughout an experiment conducted after several experiments without gouge removal. (2) The friction drop was larger and the recurrence time was shorter in the experiments with faster loading velocity. We applied a one-degree-of-freedom spring-slider model with mass to estimate the RSF parameters by fitting the stick-slip intervals and slip-weakening curves measured based on spring force and acceleration of the specimens. We developed an efficient algorithm for the numerical time integration, and we conducted forward modeling for evolution parameters (b) and the state-evolution distances (L_{c} ), keeping the direct effect parameter (a) constant. We then identified the confident range of b and L_{c} values. Comparison between the results of the experiments and our simulations suggests that both b and L_{c} increase as the cumulative slip displacement increases, and b increases and L_{c} decreases as the loading velocity increases. Conventional RSF laws could not explain the large-scale friction data, and more complex state evolution laws are needed.

  19. The Influence of Geometrical Parameters on the Buckling Behavior of Conical Shell by the Single Perturbation Load Approach

    NASA Astrophysics Data System (ADS)

    Di Pasqua, Maria Francesca; Khakimova, Regina; Castro, Saullo G. P.; Arbelo, Mariano A.; Riccio, Aniello; Degenhardt, Richard

    2015-08-01

    Since the development of the first theories to predict the buckling induced by axial compression in shells sensitive to imperfections, a significant discrepancy between theoretical and experimental results has been observed. Donnell and Koiter are among the first authors demonstrating, for these structures, the relevant influence of the geometrical imperfections on the reduction of the buckling load. Currently, the preliminary design of imperfections sensitive shell structures used in space applications is carried out according to the NASA SP-8007guideline. However, several studies have proven that this guideline leads to over-conservative design configurations when considering the geometrical and material imperfections existing in real cones. Since the pioneer work of Arbocz, alternative methods have been investigated to overcome this issue. Among the different approaches, in this paper, the Single Perturbation Load Approach (SPLA), originally developed byHühne as a deterministic way to calculate the knock-down factor of imperfection sensitive shells, is further studied. Indeed, a numerical investigation about the application of the SPLA to the simulation of the mechanical behavior of imperfection sensitive composite conical structures under axial compression is presented. This study is related to part of the work performed in the frame of the European Union (EU) project DESICOS.

  20. Biodegradation of BTEX in a fungal biofilter: influence of operational parameters, effect of shock-loads and substrate stratification.

    PubMed

    Rene, Eldon R; Mohammad, Balsam T; Veiga, María C; Kennes, Christian

    2012-07-01

    The effect of relative humidity (RH: 30% to >95%) of a gas-phase mixture composed of benzene, toluene, ethylbenzene and para-, meta- and ortho-xylenes (BTEX), inlet concentrations (0.2-12.6 g m(-3)), and empty bed residence times (EBRTs) (48-144 s) was tested in a fungi-dominant biofilter. A maximum elimination capacity (EC(max)) of 244.2 gBTEX m(-3) h(-1) was achieved at a total inlet loading rate (ILR(T)) of 371.2 gBTEXm(-3) h(-1) (RH: 65%). The transient-state response was tested by increasing the ILR(T), in two steps, from ~50 to 850 gm(-3) h(-1) and from ~50 to 320 g m(-3) h(-1), at a constant EBRT of 41.7s. Increasing the ILR(T) reduced the total BTEX removal efficiency (RE(T)) from >97% to 35%, and from >90% to 60% during medium and high shock-load, respectively. When subjected to short (4d) and long-term (7d) shut-down periods, the biofilter was able to recover high EC(max) of, respectively, 200 and 72 gBTEX m(-)3 h(-1) after resuming operation.

  1. Effects of lipid composition and preparation conditions on physical-chemical properties, technological parameters and in vitro biological activity of gemcitabine-loaded liposomes.

    PubMed

    Calvagno, Maria Grazia; Celia, Christian; Paolino, Donatella; Cosco, Donato; Iannone, Michelangelo; Castelli, Francesco; Doldo, Patrizia; Frest, Massimo

    2007-01-01

    The effects of lipid composition and preparation conditions on the physicochemical and technological properties of gemcitabine-loaded liposomes, as well as the in vitro anti-tumoral activity of various liposome formulations were investigated. Three liposome formulations were investigated: DPPC/Chol/Oleic acid (8:3:1 molar ratio, liposomes A), DPPC/Chol/DPPS (6:3:1 molar ratio, liposomes B) and DPPC/Chol/DSPE-MPEG (6:3:1 molar ratio, liposomes C). Multilamellar liposomes were prepared by using the TLE, FAT and DRV methods, while small unilamellar liposomes were obtained by extrusion through polycarbonate filters. Light scattering techniques were used to characterize liposome formulations. Loading capacity and release profiles of gemcitabine from various liposome formulations were also investigated. Caco-2 cells were used to evaluate in vitro the antitumoral activity of gemcitabine-loaded liposomes with respect to the free drug and also the intracellular drug uptake. Preparation methods and liposome lipid composition influenced both physicochemical parameters and drug delivery features. Liposomes with a size ranging from 200 nm to 7 microm were obtained. The gemcitabine entrapment was higher than that expected probably due to an interaction with the liposome lipid components. The following decreasing loading capacity order was observed: liposome B>liposome C>liposome A. Gemcitabine release from various liposome formulations is modulated by two different processes, i.e. desorption from and permeation through liposomal bilayers. MTT assay showed a greater cytotoxic effect of gemcitabine-loaded liposomes with respect to the free drug. The following decreasing anticancer activity order was observed between the various liposome formulations: liposome C>liposome A>liposome B. The increased anticancer activity is correlated to the ability of the colloidal carrier to increase the intracellular drug uptake. Due to the encouraging results and to the high liposome modularity

  2. Water quality parameters and total aerobic bacterial and vibrionaceae loads in eastern oysters (Crassostrea virginica) from oyster gardening sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oyster gardening is a practice designed to restore habitat for marine life and to improve water quality. This study determined physical and chemical water quality parameters at two oyster gardening sites in the Delaware Inland Bays and compared them with total aerobic bacteria and Vibrionaceae conc...

  3. Immediate Provisionalization and Nonfunctional Loading of a Single Implant in the Maxillary Esthetic Zone: A Clinical Presentation and Parameters for Consideration

    PubMed Central

    Michalakis, Konstantinos X.; Kalpidis, Christos D. R.; Kirmanidou, Yvone; Hirayama, Hiroshi; Calvani, Pasquale Lino; Pissiotis, Argiris L.

    2013-01-01

    Restoration of single tooth loss with implant supported prosthesis is now considered a highly predictable treatment. However, the maxillary anterior region still presents a challenge for both the prosthodontist and the periodontist because of the inherent difficulties encountered in the provisionalization and harmonic incorporation of the definitive prosthesis into patient's dentogingival complex. This paper presents a clinical case of a single implant placed immediately after the extraction of a maxillary central incisor, followed by immediate provisionalization and nonfunctional loading. The surgical and the restorative techniques are described, and the parameters of consideration for this approach are presented. PMID:24383012

  4. The impact of preparation parameters on typical attributes of chitosan-heparin nanohydrogels: particle size, loading efficiency, and drug release.

    PubMed

    Shahbazi, Mohammad-Ali; Hamidi, Mehrdad

    2013-11-01

    Today, developing an optimized nanoparticle (NP) preparation procedure is of paramount importance in all nanoparticulate drug delivery researches, leading to expanding more operative and clinically validated nanomedicines. In this study, a one-at-a-time experimental approach was used for evaluating the effect of various preparation factors on size, loading, and drug release of hydrogel NPs prepared with ionotropic gelation between heparin and chitosan. The size, loading efficiency (LE) and drug release profile of the NPs were evaluated when the chitosan molecular weight, chitosan concentration, heparin addition time to chitosan solution, heparin concentration, pH value of chitosan solution, temperature, and mixing rate were changed separately while other factors were in optimum condition. The results displayed that size and LE are highly influenced by chitosan concentration, getting an optimum of 63 ± 0.57 and 75.19 ± 2.65, respectively, when chitosan concentration was 0.75 mg/ml. Besides, heparin addition time of 3 min leaded to 74.1 ± 0.79 % LE with no sensible effect on size and release profile. In addition, pH 5.5 showed a minimum size of 63 ± 1.87, maximum LE of 73.81 ± 3.13 and the slowest drug release with 63.71 ± 3.84 % during one week. Although LE was not affected by temperature, size and release reduced to 63 ± 0 and 74.21 ± 1.99% when temperature increased from 25°C to 55°C. Also, continuous increase of mixer rate from 500 to 3500 rpm resulted in constant enhancement of LE from 58.3 ± 3.6 to 74.4 ± 2.59 as well as remarkable decrease in size from 148 ± 4.88 to 63 ± 2.64.

  5. Increases in mature brain-derived neurotrophic factor protein in the frontal cortex and basal forebrain during chronic sleep restriction in rats: possible role in initiating allostatic adaptation.

    PubMed

    Wallingford, J K; Deurveilher, S; Currie, R W; Fawcett, J P; Semba, K

    2014-09-26

    Chronic sleep restriction (CSR) has various negative consequences on cognitive performance and health. Using a rat model of CSR that uses alternating cycles of 3h of sleep deprivation (using slowly rotating activity wheels) and 1h of sleep opportunity continuously for 4 days ('3/1' protocol), we previously observed not only homeostatic but also allostatic (adaptive) sleep responses to CSR. In particular, non-rapid eye movement sleep (NREMS) electroencephalogram (EEG) delta power, an index of sleep intensity, increased initially and then declined gradually during CSR, with no rebound during a 2-day recovery period. To study underlying mechanisms of these allostatic responses, we examined the levels of brain-derived neurotrophic factor (BDNF), which is known to regulate NREMS EEG delta activity, during the same CSR protocol. Mature BDNF protein levels were measured in the frontal cortex and basal forebrain, two brain regions involved in sleep and EEG regulation, and the hippocampus, using Western blot analysis. Adult male Wistar rats were housed in motorized activity wheels, and underwent the 3/1 CSR protocol for 27 h, for 99 h, or for 99 h followed by 24h of recovery. Additional rats were housed in either locked wheels (locked wheel controls [LWCs]) or unlocked wheels that rats could rotate freely (wheel-running controls [WRCs]). BDNF levels did not differ between WRC and LWC groups. BDNF levels were increased, compared to the control levels, in all three brain regions after 27 h, and were increased less strongly after 99 h, of CSR. After 24h of recovery, BDNF levels were at the control levels. This time course of BDNF levels parallels the previously reported changes in NREMS delta power during the same CSR protocol. Changes in BDNF protein levels in the cortex and basal forebrain may be part of the molecular mechanisms underlying allostatic sleep responses to CSR.

  6. A model for homeopathic remedy effects: low dose nanoparticles, allostatic cross-adaptation, and time-dependent sensitization in a complex adaptive system

    PubMed Central

    2012-01-01

    Background This paper proposes a novel model for homeopathic remedy action on living systems. Research indicates that homeopathic remedies (a) contain measurable source and silica nanoparticles heterogeneously dispersed in colloidal solution; (b) act by modulating biological function of the allostatic stress response network (c) evoke biphasic actions on living systems via organism-dependent adaptive and endogenously amplified effects; (d) improve systemic resilience. Discussion The proposed active components of homeopathic remedies are nanoparticles of source substance in water-based colloidal solution, not bulk-form drugs. Nanoparticles have unique biological and physico-chemical properties, including increased catalytic reactivity, protein and DNA adsorption, bioavailability, dose-sparing, electromagnetic, and quantum effects different from bulk-form materials. Trituration and/or liquid succussions during classical remedy preparation create “top-down” nanostructures. Plants can biosynthesize remedy-templated silica nanostructures. Nanoparticles stimulate hormesis, a beneficial low-dose adaptive response. Homeopathic remedies prescribed in low doses spaced intermittently over time act as biological signals that stimulate the organism’s allostatic biological stress response network, evoking nonlinear modulatory, self-organizing change. Potential mechanisms include time-dependent sensitization (TDS), a type of adaptive plasticity/metaplasticity involving progressive amplification of host responses, which reverse direction and oscillate at physiological limits. To mobilize hormesis and TDS, the remedy must be appraised as a salient, but low level, novel threat, stressor, or homeostatic disruption for the whole organism. Silica nanoparticles adsorb remedy source and amplify effects. Properly-timed remedy dosing elicits disease-primed compensatory reversal in direction of maladaptive dynamics of the allostatic network, thus promoting resilience and recovery from

  7. Minimum Detectable Change in Medial Tibiofemoral Contact Force Parameters: Derivation and Application to a Load-Altering Intervention.

    PubMed

    Barrios, Joaquin; Willson, John

    2017-04-01

    Medial tibiofemoral joint contact forces can be estimated using musculoskeletal models. To assess change in these forces that accompany load-modifying interventions, minimum detectable change (MDC) thresholds must be established. The primary study purpose was to derive MDCs for medial tibiofemoral peak force and force impulse during walking. The secondary purpose was to identify the proportions of individuals exhibiting reductions greater than these MDCs when walking with lateral foot wedging. Eight healthy individuals provided 3-dimensional gait data over 3 test sessions to serve as inputs for an inverse dynamics-driven medial tibiofemoral contact force model, from which MDCs for peak force and impulse were derived. The MDC was 0.246 BW (8.7%) for peak force and 0.0385 BW∙s (3.7%) for impulse. Then, 25 healthy individuals provided gait data by walking with and without 6° laterally wedged foot orthoses, and the proportion of individuals exhibiting changes in medial tibiofemoral contact peak force and impulse values exceeding the MDC threshold was determined. For impulse and peak force, 52% and 4% of participants exhibited a decrease exceeding the MDC, respectively. In summary, medial tibiofemoral contact force MDCs were derived, with impulse showing greater sensitivity than peak force to the effects of a biomechanical intervention.

  8. Eccentric and concentric loading of the triceps surae: an in vivo study of dynamic muscle and tendon biomechanical parameters.

    PubMed

    Chaudhry, Saira; Morrissey, Dylan; Woledge, Roger C; Bader, Dan L; Screen, Hazel R C

    2015-04-01

    Triceps surae eccentric exercise is more effective than concentric exercise for treating Achilles tendinopathy, however the mechanisms underpinning these effects are unclear. This study compared the biomechanical characteristics of eccentric and concentric exercises to identify differences in the tendon load response. Eleven healthy volunteers performed eccentric and concentric exercises on a force plate, with ultrasonography, motion tracking, and EMG applied to measure Achilles tendon force, lower limb movement, and leg muscle activation. Tendon length was ultrasonographically tracked and quantified using a novel algorithm. The Fourier transform of the ground reaction force was also calculated to investigate for tremor, or perturbations. Tendon stiffness and extension did not vary between exercise types (P = .43). However, tendon perturbations were significantly higher during eccentric than concentric exercises (25%-40% higher, P = .02). Furthermore, perturbations during eccentric exercises were found to be negatively correlated with the tendon stiffness (R2 = .59). The particular efficacy of eccentric exercise does not appear to result from variation in tendon stiffness or extension within a given session. However, varied perturbation magnitude may have a role in mediating the observed clinical effects. This property is subject-specific, with the source and clinical time-course of such perturbations requiring further research.

  9. Influence of notch shape on deformation mechanisms and energy parameters of fracture of 12Cr1MoV steel under impact loading

    NASA Astrophysics Data System (ADS)

    Panin, S. V.; Vlasov, I. V.; Maruschak, P. O.; Moiseenko, D. D.; Berto, F.; Vinogradov, A.; Bischak, R. T.

    2016-11-01

    Impact loading curves and fracture energy of the notched 12Cr1MoV ductile steel specimens are analyzed. The qualitative description and quantitative parameters are obtained for major stages of ductile and brittle fracture depending on the shape of the notch and the stress stiffness ahead. It is shown that a zone with enhanced plasticity is formed in the vicinity of V-, U-, and I-shaped notches at 20°C testing temperature, giving rise to ductile fracture. The stress stiffness at the notch tip increased with testing temperature reduced to -40°C. Using the quantitative description of fracture surfaces, a physical-mechanical scheme of the specimen fracture was suggested for the case of enhanced and localized (constrained) plasticity near the stress concentrator tip.

  10. Exploring the relationship between hydrologic parameters and nutrient loads using digital elevation model and GIS - a case study from Sugarcreek headwaters, Ohio, U.S.A.

    PubMed

    Prasad, V Krishna; Ortiz, Ariel; Stinner, Ben; McCartney, David; Parker, Jason; Hudgins, Deana; Hoy, Casey; Moore, Richard

    2005-11-01

    Ohio is typical among the Midwestern and Eastern United States with high levels of water pollutants, the main sources being from agriculture. In this study, we used a digital elevation model in conjunction with hydrological indices to determine the role of landscape complexity affecting the spatial and temporal variation in pollutant levels, in one of the most impaired headwater streams in Ohio. More than eighty five percent of the study area is dominated by agriculture. Spatial distribution of slope (S), altitude and wetness index along with other watershed parameters such as flow direction, flow accumulation, stream networks, flow stream orders and erosion index were used within a Geographic Information Systems framework to quantify variation in nitrate and phosphate loads to headwater streams. Stream monitoring data for nutrient loads were used to correlate the observed spatial and temporal patterns with hydrological parameters using multiple linear regressions. Results from the wetness index calculated from a digital elevation model suggested a range of 0.10-16.39, with more than 35% having values less than 4.0. A Revised Universal Soil Loss Equation (RUSLE) predicted soil loss in the range of 0.01-4.0 t/ha/yr. Nitrate nitrogen levels in the study area paralleled precipitation patterns over time, with higher nitrate levels corresponding to high precipitation. Atmospheric deposition through precipitation could explain approximately 35% of total nitrate levels observed in streams. Among the different topographic variables and hydrological indices, results from the step-wise multiple regression suggested the following best predictors, (1) elevation range and upstream flow length for nitrate, (2) flow direction and upstream flow length for ammonia-nitrogen and slope, and (3) elevation range for phosphate levels. Differences in the landscape models observed for nitrate, phosphate and ammonia-nitrogen in the surface waters were attributed partly to differences in the

  11. Time-domain parameter identification of aeroelastic loads by forced-vibration method for response of flexible structures subject to transient wind

    NASA Astrophysics Data System (ADS)

    Cao, Bochao

    Slender structures representing civil, mechanical and aerospace systems such as long-span bridges, high-rise buildings, stay cables, power-line cables, high light mast poles, crane-booms and aircraft wings could experience vortex-induced and buffeting excitations below their design wind speeds and divergent self-excited oscillations (flutter) beyond a critical wind speed because these are flexible. Traditional linear aerodynamic theories that are routinely applied for their response prediction are not valid in the galloping, or near-flutter regime, where large-amplitude vibrations could occur and during non-stationary and transient wind excitations that occur, for example, during hurricanes, thunderstorms and gust fronts. The linear aerodynamic load formulation for lift, drag and moment are expressed in terms of aerodynamic functions in frequency domain that are valid for straight-line winds which are stationary or weakly-stationary. Application of the frequency domain formulation is restricted from use in the nonlinear and transient domain because these are valid for linear models and stationary wind. The time-domain aerodynamic force formulations are suitable for finite element modeling, feedback-dependent structural control mechanism, fatigue-life prediction, and above all modeling of transient structural behavior during non-stationary wind phenomena. This has motivated the developing of time-domain models of aerodynamic loads that are in parallel to the existing frequency-dependent models. Parameters defining these time-domain models can be now extracted from wind tunnel tests, for example, the Rational Function Coefficients defining the self-excited wind loads can be extracted using section model tests using the free vibration technique. However, the free vibration method has some limitations because it is difficult to apply at high wind speeds, in turbulent wind environment, or on unstable cross sections with negative aerodynamic damping. In the current

  12. The stress of growing old: sex- and season-specific effects of age on allostatic load in wild grey mouse lemurs.

    PubMed

    Hämäläinen, Anni; Heistermann, Michael; Kraus, Cornelia

    2015-08-01

    Chronic stress [i.e. long-term elevation of glucocorticoid (GC) levels] and aging have similar, negative effects on the functioning of an organism. Aged individuals' declining ability to regulate GC levels may therefore impair their ability to cope with stress, as found in humans. The coping of aged animals with long-term natural stressors is virtually unstudied, even though the ability to respond appropriately to stressors is likely integral to the reproduction and survival of wild animals. To assess the effect of age on coping with naturally fluctuating energetic demands, we measured stress hormone output via GC metabolites in faecal samples (fGCM) of wild grey mouse lemurs (Microcebus murinus) in different ecological seasons. Aged individuals were expected to exhibit elevated fGCM levels under energetically demanding conditions. In line with this prediction, we found a positive age effect in the dry season, when food and water availability are low and mating takes place, suggesting impaired coping of aged wild animals. The age effect was significantly stronger in females, the longer-lived sex. Body mass of males but not females correlated positively with fGCM in the dry season. Age or body mass did not influence fGCM significantly in the rainy season. The sex- and season-specific predictors of fGCM may reflect the differential investment of males and females into reproduction and longevity. A review of prior research indicates contradictory aging patterns in GC regulation across and even within species. The context of sampling may influence the likelihood of detecting senescent declines in GC functioning.

  13. Multi-parameter scaling of divertor power load profiles in D, H and He plasmas on JET and implications for ITER

    NASA Astrophysics Data System (ADS)

    Fundamenski, W.; Eich, T.; Devaux, S.; Jachmich, S.; Jakubowski, M.; Thomsen, H.; Arnoux, G.; Militello, F.; Havlickova, E.; Moulton, D.; Brezinsek, S.; Maddison, G.; McCormick, K.; Huber, A.; EFDA Contributors, JET

    2011-08-01

    Inter-ELM and ELM divertor power loads were measured on JET in dedicated deuterium, hydrogen and helium discharges. Matched triplets (D, H, He) were obtained for different values of magnetic field, B, plasma current, Ip, line average plasma density, n, and heating power, P. In this paper, the above experiments are described and the results are presented in terms of empirical scalings of inter-ELM and ELM wetted areas (power widths) versus engineering parameters. The inter-ELM wetted area on the outer target is found to scale roughly as B^{-0.57+/- 0.32}q_{cyl}^{1.0+/- 0.31} P_{sol}^{0.23+/- 0.09} Z^{0.3+/- 0.1}n^0A^0 , where A and Z and the fuel ion mass and charge numbers, and qcyl is the cylindrical safety factor, and the ELM wetted area as B^{-0.82+/- 0.25}q_{cyl}^{0.82+/- 0.25} n^{0.24+/- 0.19}P_{sol}^{0.20+/- 0.11} E_{ELM,5}^{0.22+/- 0.1} A^0Z^0 . The obtained inter-ELM scalings are then compared with those previously reported in the literature and with a wide range of 0D theoretical predictions. For this purpose a family of scrape-off layer power width models was constructed based on a permutation of different assumptions for parallel and perpendicular transport. It is found that a combination of parallel electron conduction and drift-ordered radial convection offers the best overall match to the empirical data, closely followed by models based on marginal stability to interchange/ballooning modes and ion convection with transport ordered radial velocity. Finally, implications for ITER are tentatively drawn, and a revised estimate for the power width in ITER is proposed. Extrapolating to ITER based on the empirical JET scaling and the optimum size scaling of R0.7±0.6, obtained based on comparison with simple models, yields a median outer target inter-ELM power width of ~5.5 ± 2 mm (mapped to the outer mid-plane), in close agreement with previous estimates and the ITER design value. The most pessimistic forecasts (little or no size scaling and inverse linear

  14. Use of an allostatic neurotechnology by adolescents with postural orthostatic tachycardia syndrome (POTS) is associated with improvements in heart rate variability and changes in temporal lobe electrical activity.

    PubMed

    Fortunato, John E; Tegeler, Catherine L; Gerdes, Lee; Lee, Sung W; Pajewski, Nicholas M; Franco, Meghan E; Cook, Jared F; Shaltout, Hossam A; Tegeler, Charles H

    2016-03-01

    Autonomic dysregulation and heterogeneous symptoms characterize postural orthostatic tachycardia syndrome (POTS). This study evaluated the effect of high-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM(®)), a noninvasive, allostatic neurotechnology for relaxation and auto-calibration of neural oscillations, on heart rate variability, brain asymmetry, and autonomic symptoms, in adolescents with POTS. Seven subjects with POTS (three males, ages 15-18) underwent a median of 14 (10-16) HIRREM sessions over 13 (8-17) days. Autonomic function was assessed from 10-min continuous heart rate and blood pressure recordings, pre- and post-HIRREM. One-minute epochs of temporal high-frequency (23-36 Hz) brain electrical activity data (T3 and T4, eyes closed) were analyzed from baseline HIRREM assessment and subsequent sessions. Subjects rated autonomic symptoms before and after HIRREM. Four of seven were on fludrocortisone, which was stopped before or during their sessions. Heart rate variability in the time domain (standard deviation of the beat-to-beat interval) increased post-HIRREM (mean increase 51%, range 10-143, p = 0.03), as did baroreflex sensitivity (mean increase in high-frequency alpha 65%, range -6 to 180, p = 0.05). Baseline temporal electrical asymmetry negatively correlated with change in asymmetry from assessment to the final HIRREM session (p = 0.01). Summed high-frequency amplitudes at left and right temporal lobes decreased a median of 3.8 μV (p = 0.02). There was a trend for improvements in self-reported symptoms related to the autonomic nervous system. Use of HIRREM was associated with reduced sympathetic bias in autonomic cardiovascular regulation, greater symmetry and reduced amplitudes in temporal lobe high-frequency electrical activity, and a trend for reduced autonomic symptoms. Data suggest the potential for allostatic neurotechnology to facilitate increased flexibility in autonomic cardiovascular regulation, possibly

  15. Design of calcium phosphate ceramics for drug delivery applications in bone diseases: A review of the parameters affecting the loading and release of the therapeutic substance.

    PubMed

    Parent, Marianne; Baradari, Hiva; Champion, Eric; Damia, Chantal; Viana-Trecant, Marylène

    2017-02-21

    Effective treatment of critical-size defects is a key challenge in restorative surgery of bone. The strategy covers the implantation of biocompatible, osteoconductive, bioactive and biodegradable devices which (1) well interact with native tissue, mimic multi-dimensional and hierarchical structure of bone and (2) are able to enhance bone repair, treating post implantation pathologies or bone diseases by local delivery of therapeutic agents. Among different options, calcium phosphate biomaterials are found to be attractive choices, due to their excellent biocompatibility, customisable bioactivity and biodegradability. Several approaches have been established to enhance this material ability to be loaded with a therapeutic agent, in order to obtain an in situ controlled release that meets the clinical needs. This article reviews the most important factors influencing on both drug loading and release capacity of porous calcium phosphate bone substitutes. Characteristics of the carrier, drug/carrier interactions, experimental conditions of drug loading and evaluation of drug delivery are considered successively.

  16. Effect of Monotherapy with Darunavir/Ritonavir on Viral Load in Seminal Fluid, and Quality Parameters of Semen in HIV-1-Positive Patients.

    PubMed

    Lopez-Ruz, Miguel A; Navas, Purificación; López-Zúñiga, Miguel A; Gonzalvo, María Carmen; Sampedro, Antonio; Pasquau, Juan; Hidalgo-Tenorio, Carmen; Javier, Rosario; Castilla, José A

    2016-01-01

    Patients with human immunodeficiency virus type 1 (HIV-1) who receive antiretroviral therapy (ART) often achieve increased survival and improved quality of life. In this respect, monotherapy with darunavir/ritonavir (mDRV/r) can be a useful treatment strategy. This prospective study analyses the effect of mDRV/r on sperm quality and viral load in a group of 28 patients who had previously been given conventional ART and who had recorded a viral load <20 copies/mL for at least six months. These patients were given mDRV/r at a dose of 800/100 mg for 48 weeks. At baseline (V0), CD4, CD8, FSH, LH and testosterone levels were measured, together with HIV-1 viral load in plasma and semen. In addition, seminal fluid quality was studied before mDRV/r treatment was prescribed. At week 48 (V1), HIV-1 viral load in plasma and semen and the quality of the seminal fluid were again measured. The results obtained indicate that at V0, 10% of the patients with ART had a positive viral load in seminal fluid (>20 copies/ml), and that at V1, after mDRV/r treatment, this figure had fallen to 3%. The quality of seminal fluid was close to normal in 57% of patients at V0 and in 62% at V1. We conclude that, similar to ART, mDRV/r maintains HIV-1 viral load in most patients, and that there is no worsening in seminal fluid quality.

  17. Effect of Monotherapy with Darunavir/Ritonavir on Viral Load in Seminal Fluid, and Quality Parameters of Semen in HIV-1-Positive Patients

    PubMed Central

    Lopez-Ruz, Miguel A.; Navas, Purificación; López-Zúñiga, Miguel A.; Gonzalvo, María Carmen; Sampedro, Antonio; Pasquau, Juan; Hidalgo-Tenorio, Carmen; Javier, Rosario; Castilla, José A.

    2016-01-01

    Patients with human immunodeficiency virus type 1 (HIV-1) who receive antiretroviral therapy (ART) often achieve increased survival and improved quality of life. In this respect, monotherapy with darunavir/ritonavir (mDRV/r) can be a useful treatment strategy. This prospective study analyses the effect of mDRV/r on sperm quality and viral load in a group of 28 patients who had previously been given conventional ART and who had recorded a viral load <20 copies/mL for at least six months. These patients were given mDRV/r at a dose of 800/100 mg for 48 weeks. At baseline (V0), CD4, CD8, FSH, LH and testosterone levels were measured, together with HIV-1 viral load in plasma and semen. In addition, seminal fluid quality was studied before mDRV/r treatment was prescribed. At week 48 (V1), HIV-1 viral load in plasma and semen and the quality of the seminal fluid were again measured. The results obtained indicate that at V0, 10% of the patients with ART had a positive viral load in seminal fluid (>20 copies/ml), and that at V1, after mDRV/r treatment, this figure had fallen to 3%. The quality of seminal fluid was close to normal in 57% of patients at V0 and in 62% at V1. We conclude that, similar to ART, mDRV/r maintains HIV-1 viral load in most patients, and that there is no worsening in seminal fluid quality. PMID:27442068

  18. Tank tests to determine the effect of varying design parameters of planing-tail hulls II : effect of varying depth of step, angle of after- body keel, length of afterbody chine, and gross load

    NASA Technical Reports Server (NTRS)

    Dawson, John R; Mckann, Robert; Hay, Elizabeth S

    1946-01-01

    The second part of a series of tests made in Langley tank no. 2 to determine the effect of varying design parameters of planing-tail hulls is presented. Results are given to show the effects on resistance characteristics of varying angle of afterbody keel, depth of step, and length of afterbody chine. The effect of varying the gross load is shown for one configuration. The resistance characteristics of planing-tail hulls are compared with those of a conventional flying-boat hull. The forces on the forebody and afterbody of one configuration are compared with the forces on a conventional hull. Increasing the angle of afterbody keel had small effect on hump resistance and no effect on high-speed resistance but increased free-to-trim resistance at intermediate speeds. Increasing the depth of step increased hump resistance, had little effect on high-speed resistance, and increased free-to-trim resistance at intermediate speeds. Omitting the chines on the forward 25 percent of the afterbody had no appreciable effect on resistance. Omitting 70 percent of the chine length had almost no effect on maximum resistance but broadened the hump and increased spray around the afterbody. Load-resistance ratio at the hump decreased more rapidly with increasing load coefficient for the planing-tail hull than for the representative conventional hull, although the load-resistance ratio at the hump was greater for the planing-tail hull than for the conventional hull throughout the range of loads tested. At speeds higher than hump speed, load-resistance ratio for the planing-tail hull was a maximum at a particular gross load and was slightly less at heavier and lighter gross loads. The planing-tail hull was found to have lower resistance than the conventional hull at both the hump and at high speeds, but at intermediate speeds there was little difference. The lower hump resistance of the planing-tail hull was attributed to the ability of the afterbody to carry a greater percentage of the

  19. Computation of load performance and other parameters of extra high speed modified Lundell alternators from 3D-FE magnetic field solutions

    NASA Technical Reports Server (NTRS)

    Wang, R.; Demerdash, N. A.

    1992-01-01

    The combined magnetic vector potential - magnetic scalar potential method of computation of 3D magnetic fields by finite elements, introduced in a companion paper, in combination with state modeling in the abc-frame of reference, are used for global 3D magnetic field analysis and machine performance computation under rated load and overload condition in an example 14.3 kVA modified Lundell alternator. The results vividly demonstrate the 3D nature of the magnetic field in such machines, and show how this model can be used as an excellent tool for computation of flux density distributions, armature current and voltage waveform profiles and harmonic contents, as well as computation of torque profiles and ripples. Use of the model in gaining insight into locations of regions in the magnetic circuit with heavy degrees of saturation is demonstrated. Experimental results which correlate well with the simulations of the load case are given.

  20. Sediment Loads and Yield, and Selected Water-Quality Parameters in Clear Creek, Carson City and Douglas County, Nevada, Water Years 2004-07

    USGS Publications Warehouse

    Seiler, Ralph L.; Wood, James L.

    2009-01-01

    Some reaches of Clear Creek above U.S. Highway 395 have experienced severe erosion as a result of fires, extreme precipitation events, and past and current human activities in the basin. Previous evaluations of erosion in the basin have concluded that most of the sediment produced and transported in the basin was associated with U.S. Highway 50, a four-lane highway that roughly parallels Clear Creek through much of the basin. During this study (water years 2004-07), construction of roads and a large residential area and golf course in the area began and are likely to affect water quality and sediment transport in the basin. Sediment data were collected between October 2003 and September 2007 (water years 2004-07) from three sites along Clear Creek. Annual suspended-sediment load was estimated to range from 1,456 tons in water year 2006 to only 100 tons in water year 2004, which corresponds to suspended-sediment yields of 93.9 tons per square mile per year in 2006 to 6.4 tons per square mile per year in 2004. In water year 2006, the suspended-sediment load on December 31, 2005, alone exceeded the combined annual load for water years 2004, 2005, and 2007. Bedload sediment was estimated to comprise 73 percent of total sediment load in the creek. Mean annual suspended-sediment yield in Clear Creek basin was much greater than yields in the Logan House, Edgewood, and Glenbrook Creek basins in the adjacent Lake Tahoe basin. Comparison of data collected during this study with data collected by university researchers in the 1970s is inconclusive as to whether fundamental changes in basin sediment characteristics have occurred during the 30-year period because different methods and sampling locations were used in the earlier studies.

  1. Load cell

    DOEpatents

    Spletzer, Barry L.

    1998-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs, each directly proportional to one of the six general load components.

  2. Load cell

    DOEpatents

    Spletzer, B.L.

    1998-12-15

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs, each directly proportional to one of the six general load components. 16 figs.

  3. Load cell

    DOEpatents

    Spletzer, Barry L.

    2001-01-01

    A load cell combines the outputs of a plurality of strain gauges to measure components of an applied load. Combination of strain gauge outputs allows measurement of any of six load components without requiring complex machining or mechanical linkages to isolate load components. An example six axis load cell produces six independent analog outputs which can be combined to determine any one of the six general load components.

  4. The Design of Nanostructured Metronidazole-Loaded HPC/Oxide Xerogel Composites: Influence of the Formulation Parameters on In Vitro Characterisation.

    PubMed

    Czarnobaj, Katarzyna

    2015-10-01

    In this study, oxide and polymer/oxide xerogels with metronidazole were prepared and examined as carriers of drug for the local application to the bone. The nanoporous SiO2-CaO-P2O5 and HPC-SiO2-CaO-P2O5 xerogel materials with different amounts of the polymer [hydroxypropyl cellulose (HPC)] were prepared using the sol-gel technology, and their physicochemical properties were characterised with respect to chemical structure [by Fourier transform infrared spectroscopy (FTIR)], porosity and the specific surface area of solids (BET), crystallinity [by X-ray powder diffraction (XRD)], morphology [by scanning electron microscope (SEM)] and the in vitro release of the metronidazole over time (by UV-vis spectroscopy, in the ultraviolet light region). HPC-modified oxide xerogels as the carriers of drug showed slower release of metronidazole, due to the structure and stronger interactions with drug as compared with the pure oxide xerogel. Kinetic analysis indicated diffusional mechanism of drug release from all xerogel carriers. HPC addition to the oxide material resulted in a decrease in the porosity and improved the bioactive properties of xerogels. Obtained results for xerogel composites suggest that the metronidazole-loaded xerogels could be attractive candidates for local delivery systems particularly to a bone.

  5. Damage Monitoring of Unidirectional C/SiC Ceramic-Matrix Composite under Cyclic Fatigue Loading using A Hysteresis Loss Energy-Based Damage Parameter at Room and Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Longbiao, Li

    2016-06-01

    The damage evolution of unidirectional C/SiC ceramic-matrix composite (CMC) under cyclic fatigue loading has been investigated using a hysteresis loss energy-based damage parameter at room and elevated temperatures. The experimental fatigue hysteresis modulus and fatigue hysteresis loss energy versus cycle number have been analyzed. By comparing the experimental fatigue hysteresis loss energy with theoretical computational values, the interface shear stress corresponding to different cycle number and peak stress has been estimated. The experimental evolution of fatigue hysteresis loss energy and fatigue hysteresis loss energy-based damage parameter versus cycle number has been predicted for unidirectional C/SiC composite at room and elevated temperatures. The predicted results of interface shear stress degradation, stress-strain hysteresis loops corresponding to different number of applied cycles, fatigue hysteresis loss energy and fatigue hysteresis loss energy-based damage parameter as a functions of cycle number agreed with experimental data. It was found that the fatigue hysteresis energy-based parameter can be used to monitor the fatigue damage evolution and predict the fatigue life of fiber-reinforced CMCs.

  6. A Load Frequency Control in an Off-Grid Sustainable Power System Based on a Parameter Adaptive PID-Type Fuzzy Controller

    NASA Astrophysics Data System (ADS)

    Ronilaya, Ferdian; Miyauchi, Hajime

    2014-10-01

    This paper presents a new implementation of a parameter adaptive PID-type fuzzy controller (PAPIDfc) for a grid-supporting inverter of battery to alleviate frequency fluctuations in a wind-diesel power system. A variable speed wind turbine that drives a permanent magnet synchronous generator is assumed for demonstrations. The PAPIDfc controller is built from a set of control rules that adopts the droop method and uses only locally measurable frequency signal. The output control signal is determined from the knowledge base and the fuzzy inference. The input-derivative gain and the output-integral gain of the PAPIDfc are tuned online. To ensure safe battery operating limits, we also propose a protection scheme called intelligent battery protection (IBP). Several simulation experiments are performed by using MATLAB®/SimPowersystems™. Next, to verify the scheme's effectiveness, the simulation results are compared with the results of conventional controllers. The results demonstrate the effectiveness of the PAPIDfc scheme to control a grid-supporting inverter of the battery in the reduction of frequency fluctuations.

  7. Research of some operating parameters and the emissions level variation in a spark ignited engine through on-board investigation methods in different loading conditions

    NASA Astrophysics Data System (ADS)

    Iosif, Ferenti; Baldean, Doru Laurean

    2014-06-01

    The present paper shows research made on a spark ignited engine with port fuel injection in different operation conditions in order to improve the comprehension about the cold start sequence, acceleration when changing the gear ratios, quality of combustion process and also any measures to be taken for pollutant reduction in such cases. The engineering endeavor encompasses the pollutants investigation during the operation time of gasoline supplied engine with four inline cylinders in different conditions. The temperature and any other parameters were measured with specific sensors installed on the engine or in the exhaust pipes. All the data collected has been evaluated using electronic investigation systems and highly developed equipment. In this manner it has enabled the outline of the idea of how pollutants of engine vary in different operating conditions. Air quality in the everyday environment is very important for the human health, and thus the ambient air quality has a well-known importance in the European pollution standards and legislation. The high level of attention directed to the pollution problem in the European lifestyle is a driving force for all kinds of studies in the field of the reduction of engine emission.

  8. Effect of different iron loads on serum and tissue biochemical parameters and liver hepcidin mRNA abundance of neonatal piglets.

    PubMed

    Lia, Mengyun; Yin, Qingqiang; Dang, Xiaowei; Chang, Juan; Zuo, Ruiyu; Zheng, Qiuhong

    2011-12-01

    Iron (Fe) is an essential and important trace element for animals. In order to study its metabolism and relationship with hepcidin, piglet models of Fe-deficiency and Fe-overload were established by intramuscular injection with different doses of Fe-dextran (150 mg Fe/ml) within 1 week of age. Twelve piglets were divided into three groups of four animals: deficiency, regular and overload group, receiving 0 ml, 1 ml and 6 ml Fe-dextran, respectively. The piglets were euthanised at the age of 7 days for analysis. The results showed that the Fe-concentrations in liver, spleen and serum of piglets in the overload group were higher than in the regular and deficiency groups (p < 0.05). In the overload group, several serum biochemical parameters, e.g. globulin, total bilirubin, total cholesterol, high density lipoprotein (HDL), malondialdehyde, glutathione peroxidase (GPx), peroxidase and xanthine oxidase were higher, while alkaline phosphatase (AKP) and triglycerides were lower, compared with the regular group (p < 0.05). The serum concentrations of AKP, total bilirubin and peroxidase in the deficiency group were lower, while HDL and GPx were higher, compared with the regular group (p < 0.05). Hepcidin mRNA abundance was 131 times lower in the liver of piglets with Fe-deficiency, and 7 times higher in the overloaded group than that in the regular group (p < 0.05). In conclusion, Fe-overload and deficiency would influence Fe-metabolism, serum biochemical indexes, oxidation state and hepcidin mRNA abundance in piglet liver.

  9. Effects of Childhood Stress Can Accumulate in the Body. Science Brief

    ERIC Educational Resources Information Center

    National Scientific Council on the Developing Child, 2008

    2008-01-01

    This brief presents the findings of a study that examined the effects of "allostatic load" on children in poverty at age 9 and 13. "Allostatic load" refers to the measurement of the cumulative wear and tear on the body that results from experiencing stress. Research shows that high allostatic load in childhood is associated with long-term…

  10. Load controller and method to enhance effective capacity of a photovoltaic power supply using a dynamically determined expected peak loading

    DOEpatents

    Perez, Richard

    2005-05-03

    A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply.

  11. LOADING DEVICE

    DOEpatents

    Ohlinger, L.A.

    1958-10-01

    A device is presented for loading or charging bodies of fissionable material into a reactor. This device consists of a car, mounted on tracks, into which the fissionable materials may be placed at a remote area, transported to the reactor, and inserted without danger to the operating personnel. The car has mounted on it a heavily shielded magazine for holding a number of the radioactive bodies. The magazine is of a U-shaped configuration and is inclined to the horizontal plane, with a cap covering the elevated open end, and a remotely operated plunger at the lower, closed end. After the fissionable bodies are loaded in the magazine and transported to the reactor, the plunger inserts the body at the lower end of the magazine into the reactor, then is withdrawn, thereby allowing gravity to roll the remaining bodies into position for successive loading in a similar manner.

  12. Carbohydrate Loading.

    ERIC Educational Resources Information Center

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  13. Use of Flexible Body Coupled Loads in Assessment of Day of Launch Flight Loads

    NASA Technical Reports Server (NTRS)

    Starr, Brett R.; Yunis, Isam; Olds, Aaron D.

    2011-01-01

    A Day of Launch flight loads assessment technique that determines running loads calculated from flexible body coupled loads was developed for the Ares I-X Flight Test Vehicle. The technique was developed to quantify DOL flight loads in terms of structural load components rather than the typically used q-alpha metric to provide more insight into the DOL loads. In this technique, running loads in the primary structure are determined from the combination of quasi-static aerodynamic loads and dynamic loads. The aerodynamic loads are calculated as a function of time using trajectory parameters passed from the DOL trajectory simulation and are combined with precalculated dynamic loads using a load combination equation. The potential change in aerodynamic load due to wind variability during the countdown is included in the load combination. In the event of a load limit exceedance, the technique allows the identification of what load component is exceeded, a quantification of how much the load limit is exceeded, and where on the vehicle the exceedance occurs. This technique was used to clear the Ares I-X FTV for launch on October 28, 2009. This paper describes the use of coupled loads in the Ares I-X flight loads assessment and summarizes the Ares I-X load assessment results.

  14. LOADED WAVEGUIDES

    DOEpatents

    Mullett, L.B.; Loach, B.G.; Adams, G.L.

    1958-06-24

    >Loaded waveguides are described for the propagation of electromagnetic waves with reduced phase velocities. A rectangular waveguide is dimensioned so as to cut-off the simple H/sub 01/ mode at the operating frequency. The waveguide is capacitance loaded, so as to reduce the phase velocity of the transmitted wave, by connecting an electrical conductor between directly opposite points in the major median plane on the narrower pair of waveguide walls. This conductor may take a corrugated shape or be an aperature member, the important factor being that the electrical length of the conductor is greater than one-half wavelength at the operating frequency. Prepared for the Second U.N. International ConferThe importance of nuclear standards is duscussed. A brief review of the international callaboration in this field is given. The proposal is made to let the International Organization for Standardization (ISO) coordinate the efforts from other groups. (W.D.M.)

  15. Space Shuttle fatigue loads spectra for prelaunch and liftoff loads

    NASA Technical Reports Server (NTRS)

    Goldish, Judith; Ortasse, Raphael

    1994-01-01

    Fatigue loads spectra for the prelaunch and liftoff flight segments of the Space Shuttle were developed. A variety o methods were used to determine the distributions of several important parameters, such as time of exposure on the launch, pad, month of launch, and wind speed. Also, some lessons learned that would be applicable to development of fatigue loads spectra for other reusable space vehicles are presented.

  16. Essentials of filoviral load quantification.

    PubMed

    Cnops, Lieselotte; van Griensven, Johan; Honko, Anna N; Bausch, Daniel G; Sprecher, Armand; Hill, Charles E; Colebunders, Robert; Johnson, Joshua C; Griffiths, Anthony; Palacios, Gustavo F; Kraft, Colleen S; Kobinger, Gary; Hewlett, Angela; Norwood, David A; Sabeti, Pardis; Jahrling, Peter B; Formenty, Pierre; Kuhn, Jens H; Ariën, Kevin K

    2016-07-01

    Quantitative measurement of viral load is an important parameter in the management of filovirus disease outbreaks because viral load correlates with severity of disease, survival, and infectivity. During the ongoing Ebola virus disease outbreak in parts of Western Africa, most assays used in the detection of Ebola virus disease by more than 44 diagnostic laboratories yielded qualitative results. Regulatory hurdles involved in validating quantitative assays and the urgent need for a rapid Ebola virus disease diagnosis precluded development of validated quantitative assays during the outbreak. Because of sparse quantitative data obtained from these outbreaks, opportunities for study of correlations between patient outcome, changes in viral load during the course of an outbreak, disease course in asymptomatic individuals, and the potential for virus transmission between infected patients and contacts have been limited. We strongly urge the continued development of quantitative viral load assays to carefully evaluate these parameters in future outbreaks of filovirus disease.

  17. Load Diffusion in Composite Structures

    NASA Technical Reports Server (NTRS)

    Horgan, Cornelius O.; Simmonds, J. G.

    2000-01-01

    This research has been concerned with load diffusion in composite structures. Fundamental solid mechanics studies were carried out to provide a basis for assessing the complicated modeling necessary for large scale structures used by NASA. An understanding of the fundamental mechanisms of load diffusion in composite subcomponents is essential in developing primary composite structures. Analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and assessing results from finite element analyses. The decay behavior of stresses and other field quantities provides a significant aid towards this process. The results are also amendable to parameter study with a large parameter space and should be useful in structural tailoring studies.

  18. Load controller and method to enhance effective capacity of a photovotaic power supply using a dynamically determined expected peak loading

    DOEpatents

    Perez, Richard

    2003-04-01

    A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply. The expected peak loading of the variable load can be dynamically determined within a defined time interval with reference to variations in the variable load.

  19. Articulatory Parameters.

    ERIC Educational Resources Information Center

    Ladefoged, Peter

    1980-01-01

    Summarizes the 16 parameters hypothesized to be necessary and sufficient for linguistic phonetic specifications. Suggests seven parameters affecting tongue shapes, three determining the positions of the lips, one controlling the position of the velum, four varying laryngeal actions, and one controlling respiratory activity. (RL)

  20. The effect of operating conditions on resistance parameters of filter media and limestone dust cake for uniformly loaded needle felts in a pilot scale test facility at ambient conditions.

    PubMed

    Saleem, Mahmood; Krammer, Gernot; Tahir, M Suleman

    2012-09-01

    Resistance parameters are essential for the prediction of pressure drop in bag filters. The reported values for limestone dust differ in magnitude and also depend on operating parameters. In this work, experimental data is provided from a pilot scale pulse-jet regenerated bag filter test facility for three types of needle felts using air and limestone dust at ambient conditions. Results reveal that specific resistance of filter media is independent of velocity while the specific resistance of filter cake increases linearly with filtration velocity. Residual pressure drop is almost constant, independent of upper pressure drop limit. The cake resistance at constant velocity fits to a second degree polynomial whereas it increases linearly with the velocity. A linear relation is reported here for all the cases. The resistance of filter cake decreases at higher upper pressure drop limit.

  1. The DEMO wall load challenge

    NASA Astrophysics Data System (ADS)

    Wenninger, R.; Albanese, R.; Ambrosino, R.; Arbeiter, F.; Aubert, J.; Bachmann, C.; Barbato, L.; Barrett, T.; Beckers, M.; Biel, W.; Boccaccini, L.; Carralero, D.; Coster, D.; Eich, T.; Fasoli, A.; Federici, G.; Firdaouss, M.; Graves, J.; Horacek, J.; Kovari, M.; Lanthaler, S.; Loschiavo, V.; Lowry, C.; Lux, H.; Maddaluno, G.; Maviglia, F.; Mitteau, R.; Neu, R.; Pfefferle, D.; Schmid, K.; Siccinio, M.; Sieglin, B.; Silva, C.; Snicker, A.; Subba, F.; Varje, J.; Zohm, H.

    2017-04-01

    For several reasons the challenge to keep the loads to the first wall within engineering limits is substantially higher in DEMO compared to ITER. Therefore the pre-conceptual design development for DEMO that is currently ongoing in Europe needs to be based on load estimates that are derived employing the most recent plasma edge physics knowledge. An initial assessment of the static wall heat load limit in DEMO infers that the steady state peak heat flux limit on the majority of the DEMO first wall should not be assumed to be higher than 1.0 MW m‑2. This compares to an average wall heat load of 0.29 MW m‑2 for the design {\\tt {EU}}{\\tt {~}}{\\tt {DEMO1}}{\\tt {~2015}} assuming a perfect homogeneous distribution. The main part of this publication concentrates on the development of first DEMO estimates for charged particle, radiation, fast particle (all static) and disruption heat loads. Employing an initial engineering wall design with clear optimization potential in combination with parameters for the flat-top phase (x-point configuration), loads up to 7 MW m‑2 (penalty factor for tolerances etc not applied) have been calculated. Assuming a fraction of power radiated from the x-point region between 1/5 and 1/3, peaks of the total power flux density due to radiation of 0.6–0.8 MW m‑2 are found in the outer baffle region. This first review of wall loads, and the associated limits in DEMO clearly underlines a significant challenge that necessitates substantial engineering efforts as well as a considerable consolidation of the associated physics basis.

  2. Intelligent electrical outlet for collective load control

    DOEpatents

    Lentine, Anthony L.; Ford, Justin R.; Spires, Shannon V.; Goldsmith, Steven Y.

    2015-10-27

    Various technologies described herein pertain to an electrical outlet that autonomously manages loads in a microgrid. The electrical outlet can provide autonomous load control in response to variations in electrical power generation supply in the microgrid. The electrical outlet includes a receptacle, a sensor operably coupled to the receptacle, and an actuator configured to selectively actuate the receptacle. The sensor measures electrical parameters at the receptacle. Further, a processor autonomously controls the actuator based at least in part on the electrical parameters measured at the receptacle, electrical parameters from one or more disparate electrical outlets in the microgrid, and a supply of generated electric power in the microgrid at a given time.

  3. Optimization of drug loading to improve physical stability of paclitaxel-loaded long-circulating liposomes.

    PubMed

    Kannan, Vinayagam; Balabathula, Pavan; Divi, Murali K; Thoma, Laura A; Wood, George C

    2015-01-01

    The effect of formulation and process parameters on drug loading and physical stability of paclitaxel-loaded long-circulating liposomes was evaluated. The liposomes were prepared by hydration-extrusion method. The formulation parameters such as total lipid content, cholesterol content, saturated-unsaturated lipid ratio, drug-lipid ratio and process parameters such as extrusion pressure and number of extrusion cycles were studied and their impact on drug loading and physical stability was evaluated. A proportionate increase in drug loading was observed with increase in the total phospholipid content. Cholesterol content and saturated lipid content in the bilayer showed a negative influence on drug loading. The short-term stability evaluation of liposomes prepared with different drug-lipid ratios demonstrated that 1:60 as the optimum drug-lipid ratio to achieve a loading of 1-1.3 mg/mL without the risk of physical instability. The vesicle size decreased with an increase in the extrusion pressure and number of extrusion cycles, but no significant trends were observed for drug loading with changes in process pressure or number of cycles. The optimization of formulation and process parameters led to a physically stable formulation of paclitaxel-loaded long-circulating liposomes that maintain size, charge and integrity during storage.

  4. The load dependence of rate constants.

    PubMed

    Walcott, Sam

    2008-06-07

    As experimental techniques in biophysics have progressed at the single molecule level, there has been considerable interest in understanding how external mechanical influences (such as load) affect chemical reactions. The majority of biophysical studies investigating load-dependent kinetics use an equation where the rate constant exponentially depends on force, which is sometimes called Bell's equation. This equation requires the determination of two parameters that describe the potential energy-strain function: k(0), which is the reaction rate in the absence of load, and x(c), which is the difference in strain between the reactant and transition states. However, there have been theoretical studies based on Kramers' theory suggesting that the rate constant should have load-dependent pre-exponential terms and nonlinear load-dependent terms in the exponential. Kramers' theory requires an exact knowledge of the potential energy-strain function, which is in general not known for an experimental system. Here, we derive a general approximation of Kramers' theory where the potential energy-strain function is described by five parameters, which can, for small loads, be reduced to four-, three-, and finally to two parameters (Bell's equation). We then use an idealized physical system to validate our approximations to Kramers' theory and show how they can predict parameters of interest (such as k(0) and x(c)) better than Bell's equation. Finally, we show previously published experimental data that are not well fitted by Bell's equation but are adequately fitted by these more exact equations.

  5. Optical components damage parameters database system

    NASA Astrophysics Data System (ADS)

    Tao, Yizheng; Li, Xinglan; Jin, Yuquan; Xie, Dongmei; Tang, Dingyong

    2012-10-01

    Optical component is the key to large-scale laser device developed by one of its load capacity is directly related to the device output capacity indicators, load capacity depends on many factors. Through the optical components will damage parameters database load capacity factors of various digital, information technology, for the load capacity of optical components to provide a scientific basis for data support; use of business processes and model-driven approach, the establishment of component damage parameter information model and database systems, system application results that meet the injury test optical components business processes and data management requirements of damage parameters, component parameters of flexible, configurable system is simple, easy to use, improve the efficiency of the optical component damage test.

  6. Methods for Analyzing Electric Load Shape and its Variability

    SciTech Connect

    Price, Philip

    2010-05-12

    Current methods of summarizing and analyzing electric load shape are discussed briefly and compared. Simple rules of thumb for graphical display of load shapes are suggested. We propose a set of parameters that quantitatively describe the load shape in many buildings. Using the example of a linear regression model to predict load shape from time and temperature, we show how quantities such as the load?s sensitivity to outdoor temperature, and the effectiveness of demand response (DR), can be quantified. Examples are presented using real building data.

  7. Gear mesh stiffness and load sharing in planetary gearing

    NASA Technical Reports Server (NTRS)

    Kasuba, R.; August, R.

    1984-01-01

    An interactive computerized analysis was developed for determining load sharing among planetary gears. The load sharing is established as a function of transmitted torque, degree of sun gear fixity, component flexibility, gear tooth quality, and phasing of individual planet gears. A nonlinear variable gear tooth mesh stiffness model was used to simulate the sun/plant and planet/ring gear meshes. The determined load sharing and gear mesh stiffness parameters then can be used for the subsequent assessment of dynamic load factors.

  8. Load sensing system

    DOEpatents

    Sohns, Carl W.; Nodine, Robert N.; Wallace, Steven Allen

    1999-01-01

    A load sensing system inexpensively monitors the weight and temperature of stored nuclear material for long periods of time in widely variable environments. The system can include an electrostatic load cell that encodes weight and temperature into a digital signal which is sent to a remote monitor via a coaxial cable. The same cable is used to supply the load cell with power. When multiple load cells are used, vast

  9. Heat Load Estimator for Smoothing Pulsed Heat Loads on Supercritical Helium Loops

    NASA Astrophysics Data System (ADS)

    Hoa, C.; Lagier, B.; Rousset, B.; Bonnay, P.; Michel, F.

    Superconducting magnets for fusion are subjected to large variations of heat loads due to cycling operation of tokamaks. The cryogenic system shall operate smoothly to extract the pulsed heat loads by circulating supercritical helium into the coils and structures. However the value of the total heat loads and its temporal variation are not known before the plasma scenario starts. A real-time heat load estimator is of interest for the process control of the cryogenic system in order to anticipate the arrival of pulsed heat loads to the refrigerator and finally to optimize the operation of the cryogenic system. The large variation of the thermal loads affects the physical parameters of the supercritical helium loop (pressure, temperature, mass flow) so those signals can be used for calculating instantaneously the loads deposited into the loop. The methodology and algorithm are addressed in the article for estimating the heat load deposition before it reaches the refrigerator. The CEA patented process control has been implemented in a Programmable Logic Controller (PLC) and has been successfully validated on the HELIOS test facility at CEA Grenoble. This heat load estimator is complementary to pulsed load smoothing strategies providing an estimation of the optimized refrigeration power. It can also effectively improve the process control during the transient between different operating modes by adjusting the refrigeration power to the need. This way, the heat load estimator participates to the safe operation of the cryogenic system.

  10. Supergranular Parameters

    NASA Astrophysics Data System (ADS)

    Udayashankar, Paniveni

    2016-07-01

    I study the complexity of supergranular cells using intensity patterns from Kodaikanal solar observatory. The chaotic and turbulent aspect of the solar supergranulation can be studied by examining the interrelationships amongst the parameters characterizing supergranular cells namely size, horizontal flow field, lifetime and physical dimensions of the cells and the fractal dimension deduced from the size data. The findings are supportive of Kolmogorov's theory of turbulence. The Data consists of visually identified supergranular cells, from which a fractal dimension 'D' for supergranulation is obtained according to the relation P α AD/2 where 'A' is the area and 'P' is the perimeter of the supergranular cells. I find a fractal dimension close to about 1.3 which is consistent with that for isobars and suggests a possible turbulent origin. The cell circularity shows a dependence on the perimeter with a peak around (1.1-1.2) x 105 m. The findings are supportive of Kolmogorov's theory of turbulence.

  11. Acoustic loading effects on oscillating rod bundles

    SciTech Connect

    Lin, W.H.

    1980-01-01

    An analytical study of the interaction between an infinite acoustic medium and a cluster of circular rods is described. The acoustic field due to oscillating rods and the acoustic loading on the rods are first solved in a closed form. The acoustic loading is then used as a forcing function for rod responses, and the acousto-elastic couplings are solved simultaneously. Numerical examples are presented for several cases to illustrate the effects of various system parameters on the acoustic reaction force coefficients. The effect of the acoustic loading on the coupled eigenfrequencies are discussed.

  12. Optimal airframe synthesis for gust loads

    NASA Technical Reports Server (NTRS)

    Hajela, P.

    1986-01-01

    An optimization capability for sizing airframe structures that are subjected to a combination of deterministic and random flight loads was established. The random vibration environment introduces the need for selecting a statistical process that best describes the random loads and permits computation of the dynamic response parameters of interest. Furthermore, it requires a formulation of design constraints that would minimize the conservativeness in the design and retain computational viability. The random loads are treated as a stationary, homogeneous process with a Gaussian probability distribution. The formulation of the analysis problem, the structure of the optimization programming system and a representative numerical example are discussed.

  13. Load Model Data Tool

    SciTech Connect

    David Chassin, Pavel Etingov

    2013-04-30

    The LMDT software automates the process of the load composite model data preparation in the format supported by the major power system software vendors (GE and Siemens). Proper representation of the load composite model in power system dynamic analysis is very important. Software tools for power system simulation like GE PSLF and Siemens PSSE already include algorithms for the load composite modeling. However, these tools require that the input information on composite load to be provided in custom formats. Preparation of this data is time consuming and requires multiple manual operations. The LMDT software enables to automate this process. Software is designed to generate composite load model data. It uses the default load composition data, motor information, and bus information as an input. Software processes the input information and produces load composition model. Generated model can be stored in .dyd format supported by GE PSLF package or .dyr format supported by Siemens PSSE package.

  14. Load Induced Blindness

    PubMed Central

    Macdonald, James S. P.; Lavie, Nilli

    2008-01-01

    Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005d`) was consistently reduced with high, compared to low, perceptual load but was unaffected by the level of working memory load. Because alternative accounts in terms of expectation, memory, response bias, and goal-neglect due to the more strenuous high load task were ruled out, these experiments clearly demonstrate that high perceptual load determines conscious perception, impairing the ability to merely detect the presence of a stimulus—a phenomenon of load induced blindness. PMID:18823196

  15. Influence parameters of impact grinding mills

    NASA Technical Reports Server (NTRS)

    Hoeffl, K.; Husemann, K.; Goldacker, H.

    1984-01-01

    Significant parameters for impact grinding mills were investigated. Final particle size was used to evaluate grinding results. Adjustment of the parameters toward increased charge load results in improved efficiency; however, it was not possible to define a single, unified set to optimum grinding conditions.

  16. Phalange Tactile Load Cell

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Diftler, Myron A. (Inventor); Linn, Douglas Martin (Inventor); Platt, Robert (Inventor); Griffith, Bryan Kristian (Inventor)

    2010-01-01

    A tactile load cell that has particular application for measuring the load on a phalange in a dexterous robot system. The load cell includes a flexible strain element having first and second end portions that can be used to mount the load cell to the phalange and a center portion that can be used to mount a suitable contact surface to the load cell. The strain element also includes a first S-shaped member including at least three sections connected to the first end portion and the center portion and a second S-shaped member including at least three sections coupled to the second end portion and the center portion. The load cell also includes eight strain gauge pairs where each strain gauge pair is mounted to opposing surfaces of one of the sections of the S-shaped members where the strain gauge pairs provide strain measurements in six-degrees of freedom.

  17. Dual Operating Parameter Relationship with Engine Performance

    NASA Astrophysics Data System (ADS)

    Devi. I, Aparna; Ramesh, R.; Kumar, N. Ravi; Charan, G. Shiva

    2016-11-01

    In order to reduce emissions and maximize performance of internal combustion engines, it is important to understand the relationship between operating parameters and performance. Estimation of engine performance under simultaneous variation of operating parameters is not well addressed in literature. In the present work an attempt has been made to develop a relationship between engine performance (brake thermal efficiency) and operating parameters such as load and compression ratio. Experiments were conducted varying load and compression ratio and Brake Thermal Effiency obtained was recorded. The results of the model were validated with the experimental results.

  18. Load regulating expansion fixture

    DOEpatents

    Wagner, Lawrence M.; Strum, Michael J.

    1998-01-01

    A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located therebetween. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components.

  19. Load regulating expansion fixture

    DOEpatents

    Wagner, L.M.; Strum, M.J.

    1998-12-15

    A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils is disclosed. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located therebetween. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components. 1 fig.

  20. Load sensing system

    DOEpatents

    Sohns, C.W.; Nodine, R.N.; Wallace, S.A.

    1999-05-04

    A load sensing system inexpensively monitors the weight and temperature of stored nuclear material for long periods of time in widely variable environments. The system can include an electrostatic load cell that encodes weight and temperature into a digital signal which is sent to a remote monitor via a coaxial cable. The same cable is used to supply the load cell with power. When multiple load cells are used, vast inventories of stored nuclear material can be continuously monitored and inventoried of minimal cost. 4 figs.

  1. Dynamic localized load balancing

    NASA Astrophysics Data System (ADS)

    Balandin, Sergey I.; Heiner, Andreas P.

    2003-08-01

    Traditionally dynamic load balancing is applied in resource-reserved connection-oriented networks with a large degree of managed control. Load balancing in connectionless networks is rather rudimentary and is either static or requires network-wide load information. This paper presents a fully automated, traffic driven dynamic load balancing mechanism that uses local load information. The proposed mechanism is easily deployed in a multi-vendor environment in which only a subset of routers supports the function. The Dynamic Localized Load Balancing (DLLB) mechanism distributes traffic based on two sets of weights. The first set is fixed and is inverse proportional to the path cost, typically the sum of reciprocal bandwidths along the path. The second weight reflects the utilization of the link to the first next hop along the path, and is therefore variable. The ratio of static weights defines the ideal load distribution, the ratio of variable weights the node-local load distribution estimate. By minimizing the difference between variable and fixed ratios the traffic distribution, with the available node-local knowledge, is optimal. The above mechanism significantly increases throughput and decreases delay from a network-wide perspective. Optionally the variable weight can include load information of nodes downstream to prevent congestion on those nodes. The latter function further improves network performance, and is easily implemented on top of the standard OSPF signaling. The mechanism does not require many node resources and can be implemented on existing router platforms.

  2. Compact X-band high power load using magnetic stainless steel

    SciTech Connect

    Tantawi, S.G. |; Vlieks, A.E.

    1995-05-01

    We present design and experimental results of a high power X-band load. The load is formed as a disk-loaded waveguide structure using lossy, Type 430 stainless steel. The design parameters have been optimized using the recently developed mode-matching code MLEGO. The load has been designed for compactness while maintaining a band width greater than 300 MHz.

  3. Climatic indicators for estimating residential heating and cooling loads

    SciTech Connect

    Huang, Y.J.; Ritschard, R.; Bull, J.; Chang, L.

    1986-11-01

    An extensive data base of residential energy use generated with the DOE-2.1A simulation code provides an opportunity for correlating building loads predicted by an hourly simulation model to commonly used climatic parameters such as heating and cooling degree-days, and to newer parameters such as insolation-days and latent enthalpy-days. The identification of reliable climatic parameters for estimating cooling loads and the incremental loads for individual building components, such as changing ceiling and wall R-values, infiltration rates or window areas is emphasized.

  4. Dielectrically Loaded HTS Spiral Antenna

    NASA Astrophysics Data System (ADS)

    Ramasamy, J.; Hanna, D.; Vlasov, Y. A.; Larkins, G. L.; Moeckly, B. H.

    2004-06-01

    The objective of this work is to fabricate, test, and study a dielectrically loaded high temperature superconductor (HTS) spiral antenna that would operate in the frequency band of 10 MHz to 200 MHz. The antenna is formed by depositing and patterning a YBa2Cu3O7 (YBCO) thin film on top of 4-inch-diameter sapphire and Yittria Stabilized ZrO2 substrates. The presence of the HTS material guarantees low conductor loss in the antenna. A thick epitaxial layer of strontium titanate (STO) is then deposited on top of the YBCO for high dielectric constant loading. This set-up can be simulated using the Fidelity software routine, a Finite Difference Time Domain based program from Zeland, Inc. We have simulated the performance of this antenna structure, first in free space and then after loading with the dielectric slabs. Important parameters such as feed point impedance and antenna gain are studied for different simulation conditions. The dielectric ensures reduced feed point impedance as well as improvement of the low frequency response of the antenna.

  5. High power s-band vacuum load

    SciTech Connect

    Neubauer, Michael; Dudas, Alan; Krasnykh, Anatoly

    2016-12-29

    Through a combination of experimentation and calculation the components of a novel room temperature dry load were successfully fabricated. These components included lossy ceramic cylinders of various lengths, thicknesses, and percent of silicon carbide (SiC). The cylinders were then assembled into stainless steel compression rings by differential heating of the parts and a special fixture. Post machining of this assembly provided a means for a final weld. The ring assemblies were then measured for S-parameters, individually and in pairs using a low-cost TE10 rectangular to TE01 circular waveguide adapter specially designed to be part of the final load assembly. Matched pairs of rings were measured for assembly into the final load and a sliding short designed and fabricated to assist in determining the desired short location in the final assembly. The plan for the project was for Muons, Inc. to produce prototype loads for long-term testing at SLAC. The STTR funds for SLAC were to upgrade and operate their test station to ensure that the loads would satisfy their requirements. Phase III was to be the sale to SLAC of loads that Muons, Inc. would manufacture. However, an alternate solution that involved a rebuild of the old loads, reduced SLAC budget projections, and a relaxed time for the replacement of all loads meant that in-house labor will be used to do the upgrade without the need for the loads developed in this project. Consequently, the project was terminated before the long term testing was initiated. However, SLAC can use the upgraded test stand to compare the long-term performance of the ones produced in this project with their rebuilt loads when they are available.

  6. CRITICAL LOADS METHODS

    EPA Science Inventory

    I summarize the results of an interagency project that 1) defines a generic approach to quantifying and reporting critical loads, and 2) exercises that generic approach by examining a data rich system -- the critical loads of sulfur deposition and it's effect on the chronic acidi...

  7. Strip and load data

    NASA Technical Reports Server (NTRS)

    Jones, R. H.

    1984-01-01

    The method of taking batch data files and loading these files into the ADABAS data base management system (DBMS) is examined. This strip and load process allows the user to quickly become productive. Techniques for data fields and files definition are also included.

  8. Microbial load monitor

    NASA Technical Reports Server (NTRS)

    Caplin, R. S.; Royer, E. R.

    1977-01-01

    Design analysis of a microbial load monitor system flight engineering model was presented. Checkout of the card taper and media pump system was fabricated as well as the final two incubating reading heads, the sample receiving and card loading device assembly, related sterility testing, and software. Progress in these areas was summarized.

  9. Load induced blindness.

    PubMed

    Macdonald, James S P; Lavie, Nilli

    2008-10-01

    Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005, for a review). Here we varied the level of perceptual load in a letter-search task and assessed its effect on the conscious perception of a search-irrelevant shape stimulus appearing in the periphery, using a direct measure of awareness (present/absent reports). Detection sensitivity (d') was consistently reduced with high, compared to low, perceptual load but was unaffected by the level of working memory load. Because alternative accounts in terms of expectation, memory, response bias, and goal-neglect due to the more strenuous high load task were ruled out, these experiments clearly demonstrate that high perceptual load determines conscious perception, impairing the ability to merely detect the presence of a stimulus--a phenomenon of load induced blindness.

  10. Load Induced Blindness

    ERIC Educational Resources Information Center

    Macdonald, James S. P.; Lavie, Nilli

    2008-01-01

    Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005, for a review). Here we varied the level of…

  11. Transportation and handling loads

    NASA Technical Reports Server (NTRS)

    Ostrem, F. E.

    1971-01-01

    Criteria and recommended practices are presented for the prediction and verification of transportation and handling loads for the space vehicle structure and for monitoring these loads during transportation and handling of the vehicle or major vehicle segments. Elements of the transportation and handling systems, and the forcing functions and associated loads are described. The forcing functions for common carriers and typical handling devices are assessed, and emphasis is given to the assessment of loads at the points where the space vehicle is supported during transportation and handling. Factors which must be considered when predicting the loads include the transportation and handling medium; type of handling fixture; transport vehicle speed; types of terrain; weather (changes in pressure of temperature, wind, etc.); and dynamics of the transportation modes or handling devices (acceleration, deceleration, and rotations of the transporter or handling device).

  12. Compensator configurations for load currents' symmetrization

    NASA Astrophysics Data System (ADS)

    Rusinaru, D.; Manescu, L. G.; Dinu, R. C.

    2016-02-01

    This paper approaches aspects regarding the mitigation effects of asymmetries in 3-phase 3-wire networks. The measure consisting in connecting of load current symmetrization devices at the load coupling point is presented. A time-variation of compensators parameters is determined as a function of the time-recorded electrical values. The general sizing principle of the load current symmetrization reactive components is based on a simple equivalent model of the unbalanced 3-phase loads. By using these compensators a certain control of the power components transits is ensured in the network. The control is based on the variations laws of the compensators parameters as functions of the recorded electrical values: [B] = [T]·[M]. The link between compensator parameters and measured values is ensured by a transformation matrix [T] for each operation conditions of the supply network. Additional conditions for improving of energy and efficiency performance of the compensator are considered: i.e. reactive power compensation. The compensator sizing algorithm was implemented into a MATLAB environment software, which generate the time-evolution of the parameters of load current symmetrization device. The input data of application takes into account time-recording of the electrical values. By using the compensator sizing software, some results were achieved for the case of a consumer connected at 20 kV busbar of a distribution substation, during 24 hours measurement session. Even the sizing of the compensators aimed some additional network operation aspects (power factor correction) correlated with the total or major load symmetrizations, the harmonics aspects of the network values were neglected.

  13. Mechanical Predictors of Discomfort during Load Carriage

    PubMed Central

    Wettenschwiler, Patrick D.; Lorenzetti, Silvio; Stämpfli, Rolf; Rossi, René M.; Ferguson, Stephen J.; Annaheim, Simon

    2015-01-01

    Discomfort during load carriage is a major issue for activities using backpacks (e.g. infantry maneuvers, children carrying school supplies, or outdoor sports). It is currently unclear which mechanical parameters are responsible for subjectively perceived discomfort. The aim of this study was to identify objectively measured mechanical predictors of discomfort during load carriage. We compared twelve different configurations of a typical load carriage system, a commercially available backpack with a hip belt. The pressure distribution under the hip belt and the shoulder strap, as well as the tensile force in the strap and the relative motion of the backpack were measured. Multiple linear regression analyses were conducted to investigate possible predictors of discomfort. The results demonstrate that static peak pressure, or alternatively, static strap force is a significant (p<0.001) predictor of discomfort during load carriage in the shoulder and hip region, accounting for 85% or more of the variation in discomfort. As an additional finding, we discovered that the regression coefficients of these predictors are significantly smaller for the hip than for the shoulder region. As static peak pressure is measured directly on the body, it is less dependent on the type of load carriage system than static strap force. Therefore, static peak pressure is well suited as a generally applicable, objective mechanical parameter for the optimization of load carriage system design. Alternatively, when limited to load carriage systems of the type backpack with hip belt, static strap force is the most valuable predictor of discomfort. The regionally differing regression coefficients of both predictors imply that the hip region is significantly more tolerant than the shoulder region. In order to minimize discomfort, users should be encouraged to shift load from the shoulders to the hip region wherever possible, at the same time likely decreasing the risk of low back pain or injury

  14. Fuzzy system applications for short-term electric load forecasting

    NASA Astrophysics Data System (ADS)

    Al-Kandari, Ahmad Mohammad

    Load forecasting is an important function in economic power generation, allocation between plants (Unit Commitment Scheduling), maintenance scheduling, and for system security applications such as peak shaving by power interchange with interconnected utilities. In this thesis the problem of fuzzy short term load forecasting is formulated and solved. The thesis starts with a discussion of conventional algorithms used in short-term load forecasting. These algorithms are based on least error squares and least absolute value. The theory behind each algorithm is explained. Three different models are developed and tested in the first part of the thesis. The first model (A) is a regression model that takes into account the weather parameters in summer and winter seasons. The second model (B) is a harmonics based model, which does not account for weather parameters, but considers the parameters as a function of time. Model (B) can be used where variations in weather parameters are not available. Finally, model (C) is created as a hybrid combination of models A and B. The parameters of the three models are estimated using the two static estimation algorithms and are used later to predict the load for twenty-four hours ahead. The results obtained are discussed and conclusions are drawn for these models. In the second part of the thesis new fuzzy models are developed for crisp load power with fuzzy load parameters and for fuzzy load power with fuzzy load parameters. Three fuzzy models (A), (B) and (C) are developed. The fuzzy load model (A) is a fuzzy linear regression model for summer and winter seasons. Model (B) is a harmonic fuzzy model, which does not account for weather parameters. Finally fuzzy load model (C) is a hybrid combination of fuzzy load models (A) and (B). Estimating the fuzzy parameters for the three models turns out to be one of linear optimization. The fuzzy parameters are obtained for the three models. These parameters are used to predict the load as a

  15. Cable load sensing device

    DOEpatents

    Beus, Michael J.; McCoy, William G.

    1998-01-01

    Apparatus for sensing the magnitude of a load on a cable as the cable is employed to support the load includes a beam structure clamped to the cable so that a length of the cable lies along the beam structure. A spacer associated with the beam structure forces a slight curvature in a portion of the length of cable under a cable "no-load" condition so that the portion of the length of cable is spaced from the beam structure to define a cable curved portion. A strain gauge circuit including strain gauges is secured to the beam structure by welding. As the cable is employed to support a load the load causes the cable curved portion to exert a force normal to the cable through the spacer and on the beam structure to deform the beam structure as the cable curved portion attempts to straighten under the load. As this deformation takes place, the resistance of the strain gauges is set to a value proportional to the magnitude of the normal strain on the beam structure during such deformation. The magnitude of the normal strain is manipulated in a control device to generate a value equal to the magnitude or weight of the load supported by the cable.

  16. Load Balancing Scientific Applications

    SciTech Connect

    Pearce, Olga Tkachyshyn

    2014-12-01

    The largest supercomputers have millions of independent processors, and concurrency levels are rapidly increasing. For ideal efficiency, developers of the simulations that run on these machines must ensure that computational work is evenly balanced among processors. Assigning work evenly is challenging because many large modern parallel codes simulate behavior of physical systems that evolve over time, and their workloads change over time. Furthermore, the cost of imbalanced load increases with scale because most large-scale scientific simulations today use a Single Program Multiple Data (SPMD) parallel programming model, and an increasing number of processors will wait for the slowest one at the synchronization points. To address load imbalance, many large-scale parallel applications use dynamic load balance algorithms to redistribute work evenly. The research objective of this dissertation is to develop methods to decide when and how to load balance the application, and to balance it effectively and affordably. We measure and evaluate the computational load of the application, and develop strategies to decide when and how to correct the imbalance. Depending on the simulation, a fast, local load balance algorithm may be suitable, or a more sophisticated and expensive algorithm may be required. We developed a model for comparison of load balance algorithms for a specific state of the simulation that enables the selection of a balancing algorithm that will minimize overall runtime.

  17. Local load shedding

    SciTech Connect

    Adibi, M.M.; Thorne, D.K. )

    1988-08-01

    Equipment overloads in an underground transmission network are caused by unscheduled outages. Repairs or replacements of damaged cables and/or transformers in urban areas are inherently difficult and time-consuming. Therefore, for overloads greatly in excess of short-time ratings, speed of load shedding is of paramount importance. Under such conditions, the system operator is faced with: recognizing the problem, determining the course of action and shedding the correct amount of load at the right locations. These tasks are difficult to perform, particularly under pressure of time. Reliance on pre-specified load shedding lists is not satisfactory since the load shedding lists do not necessarily match the amounts and locations of the required loads to be shed. Clearly, there has been a need for a local load shedding scheme, which in the first order of importance, would relieve the overloaded equipment within the time limits imposed by the equipment short-time ratings and in the second order of importance, would ''minimize'' the amount of load to be curtailed. This paper describes an approach which meets the dual objective, providing a practical solution to a difficult engineering/operating problem.

  18. Load research manual. Volume 3. Load research for advanced technologies

    SciTech Connect

    Brandenburg, L.; Clarkson, G.; Grund, Jr., C.; Leo, J.; Asbury, J.; Brandon-Brown, F.; Derderian, H.; Mueller, R.; Swaroop, R.

    1980-11-01

    This three-volume manual presents technical guidelines for electric utility load research. Special attention is given to issues raised by the load data reporting requirements of the Public Utility Regulatory Policies Act of 1978 and to problems faced by smaller utilities that are initiating load research programs. The manual includes guides to load research literature and glossaries of load research and statistical terms. In Volume 3, special load research procedures are presented for solar, wind, and cogeneration technologies.

  19. LOADING MACHINE FOR REACTORS

    DOEpatents

    Simon, S.L.

    1959-07-01

    An apparatus is described for loading or charging slugs of fissionable material into a nuclear reactor. The apparatus of the invention is a "muzzle loading" type comprising a delivery tube or muzzle designed to be brought into alignment with any one of a plurality of fuel channels. The delivery tube is located within the pressure shell and it is also disposed within shielding barriers while the fuel cantridges or slugs are forced through the delivery tube by an externally driven flexible ram.

  20. 16. UPPER PASSENGER LOADING ZONE, NOTE LOADING ZONE BELOW WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. UPPER PASSENGER LOADING ZONE, NOTE LOADING ZONE BELOW WITH TURN STILES - Jefferson National Expansion Memorial Arch, Mississippi River between Washington & Poplar Streets, Saint Louis, Independent City, MO

  1. Motor characteristics in the control of a compliant load

    NASA Astrophysics Data System (ADS)

    Harokopos, E. G.; Mayne, R. W.

    1986-02-01

    This paper considers a servomechanism consisting of a DC-motor, a gear train and an inertial mass controlled through a compliant drive. The compliance is modeled as a spring between the gear box and inertia, and the interaction between the actuator and its load is considered. Dimensionless parameters are defined to describe this interaction, and the influence of the parameters on open- and closed-loop performance is discussed. System behavior is relatively sensitive to one particular dimensionless parameter related to damping provided by electromechanical interaction. Results of this effort illustrate the concept of quantitative controllability and indicate the possibility of controlling flexible loads conveniently by an appropriate choice of actuator parameters.

  2. Static and transient beam loading of a synchrotron

    SciTech Connect

    Zhang, S.Y.; Weng, W.T.

    1992-07-13

    In a synchrotron, when the beam induced current is comparable to the driver current, the RF cavity is subjected to beam loading perturbation and corrective steps have to be implemented to regain beam stability. In this paper, the static and transient beam loading will be studied. We first discuss the static beam loading, which includes the cavity detuning condition, the stability condition, and the generator power dissipation. The beam current induced beam phase deviation is used as criterion to study the transient beam loading. The upgraded and the old AGS RF system parameters are used as an example to demonstrate how to choose cavity and generator parameters to satisfy the stability requirements under the beam loading. The dynamic models for the beam loading with beam control, and the beam loading with fast power amplifier feedback are presented and analyzed. It is shown that the beam phase and radial feedbacks alone are insufficient for the transient beam loading compensation, but the fast power amplifier feedback can provide effective correction on the beam loading. The limitation of the fast feedback and the beam loading with tuning and AVC loops are also discussed.

  3. Intervertebral disc response to cyclic loading--an animal model.

    PubMed

    Ekström, L; Kaigle, A; Hult, E; Holm, S; Rostedt, M; Hansson, T

    1996-01-01

    The viscoelastic response of a lumbar motion segment loaded in cyclic compression was studied in an in vivo porcine model (N = 7). Using surgical techniques, a miniaturized servohydraulic exciter was attached to the L2-L3 motion segment via pedicle fixation. A dynamic loading scheme was implemented, which consisted of one hour of sinusoidal vibration at 5 Hz, 50 N peak load, followed by one hour of restitution at zero load and one hour of sinusoidal vibration at 5 Hz, 100 N peak load. The force and displacement responses of the motion segment were sampled at 25 Hz. The experimental data were used for evaluating the parameters of two viscoelastic models: a standard linear solid model (three-parameter) and a linear Burger's fluid model (four-parameter). In this study, the creep behaviour under sinusoidal vibration at 5 Hz closely resembled the creep behaviour under static loading observed in previous studies. Expanding the three-parameter solid model into a four-parameter fluid model made it possible to separate out a progressive linear displacement term. This deformation was not fully recovered during restitution and is therefore an indication of a specific effect caused by the cyclic loading. High variability was observed in the parameters determined from the 50 N experimental data, particularly for the elastic modulus E1. However, at the 100 N load level, significant differences between the models were found. Both models accurately predicted the creep response under the first 800 s of 100 N loading, as displayed by mean absolute errors for the calculated deformation data from the experimental data of 1.26 and 0.97 percent for the solid and fluid models respectively. The linear Burger's fluid model, however, yielded superior predictions particularly for the initial elastic response.

  4. Uncertainties in critical loads and target loads of sulphur and nitrogen for European forests: analysis and quantification.

    PubMed

    Reinds, Gert Jan; de Vries, Wim

    2010-03-15

    An analysis of the uncertainties in critical loads and target loads of sulphur (S) and nitrogen (N) for 182 European forest soils was carried out using the Very Simple Dynamic (VSD) model. The VSD model was calibrated with a Bayesian approach using prior probability functions for model parameters based on literature data, data from 200 Dutch forest sites and from simulated denitrification rates from a detailed ecosystem model. The calibration strongly improved the fit of the model to observed soil and soil solution concentrations, especially for pH and base saturation. Calibration also narrowed down the ranges in input parameters. The uncertainty analysis showed which parameters contribute most to the uncertainty in the critical loads and target loads. Base cation weathering and deposition and the parameters describing the H-Al equilibrium in the soil solution determine the uncertainty in the maximum critical loads for S, CL(max)(S), when based on the aluminium to base cation (Al/Bc) criterion. Uncertainty in CL(max)(S) based on an acid neutralizing capacity (ANC) criterion is completely determined by base cation inputs alone. The denitrification fraction is the most important source of uncertainty for the maximum critical loads of N, CL(max)(N). N uptake and N immobilisation determine the uncertainties in the critical load for N as a nutrient, CL(nut)(N). Calibration of VSD reduced the uncertainty: the coefficient of variation (CV) was reduced for all critical loads and criteria. After calibration, the CV for CL(max)(S) was below 0.4 for almost all plots; however for CL(max)(N) high values occurred for plots with high denitrification rates. Model calibration also improved the robustness of target load estimates: after calibration, no target loads were needed in any of the simulations for 40% of the plots, with the uncalibrated model there was a positive probability for the need of a target load for almost all plots.

  5. A load factor formula

    NASA Technical Reports Server (NTRS)

    Miller, Roy G

    1927-01-01

    The ultimate test of a load factor formula is experience. The chief advantages of a semi rational formula over arbitrary factors are that it fairs in between points of experience and it differentiates according to variables within a type. Structural failure of an airplane apparently safe according to the formula would call for a specific change in the formula. The best class of airplanes with which to check a load factor formula seems to be those which have experienced structural failure. Table I comprises a list of the airplanes which have experienced failure in flight traceable to the wing structure. The load factor by formula is observed to be greater than the designed strength in each case, without a single exception. Table II comprises the load factor by formula with the designed strength of a number of well-known service types. The formula indicates that by far the majority of these have ample structural strength. One case considered here in deriving a suitable formula is that of a heavy load carrier of large size and practically no reserve power.

  6. Experimental investigation on single person's jumping load model

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Wang, Haoqi; Wang, Ling

    2015-12-01

    This paper presents a modified half-sine-squared load model of the jumping impulses for a single person. The model is based on a database of 22,921 experimentally measured single jumping load cycles from 100 test subjects. Threedimensional motion capture technology in conjunction with force plates was employed in the experiment to record jumping loads. The variation range and probability distribution of the controlling parameters for the load model such as the impact factor, jumping frequency and contact ratio, are discussed using the experimental data. Correlation relationships between the three parameters are investigated. The contact ratio and jumping frequency are identified as independent model parameters, and an empirical frequency-dependent function is derived for the impact factor. The feasibility of the proposed load model is established by comparing the simulated load curves with measured ones, and by comparing the acceleration responses of a single-degree-of-freedom system to the simulated and measured jumping loads. The results show that a realistic individual jumping load can be generated by the proposed method. This can then be used to assess the dynamic response of assembly structures.

  7. Durability of Polymeric Coatings: Cyclic Loading and Free Volumes

    NASA Astrophysics Data System (ADS)

    Chen, Hongmin; Peng, Qinghua; Wu, Yichu; Li, Ying; Zhang, Junjie; Sandreczki, T. C.; Zhang, Renwu; Jean, Y. C.; Richardson, J. R.

    2002-03-01

    The mechanical durability of seven commercially polymeric coatings is investigated using slow positron beam techniques to monitor changes in sub nanometer defects during the cyclic loading process. Doppler broadened energy spectra and positron annihilation lifetime measurements were performed as a function of the slow positron energy at different periods of cycling loading. The positron annihilation dada show that both S-defect parameter and ortho-positronium intensity decrease as the loading cycles increase. The results indicate a loss of free volumes due to mechanical loading and cycling. A direct correlation between the loss of free-volume parameter and of loading cycle is observed. This is interpreted as that durability of polymeric coatings is controlled by the atomic level defects. It is shown that the slow positron beam is very successful probe in detecting the very early stages of coating degradation due to mechanical processes. Supported by NSF-CMS-9812717

  8. Tectonics of planetary loading - A general model and results

    NASA Astrophysics Data System (ADS)

    Janes, D. M.; Melosh, H. J.

    1990-12-01

    The tectonics of planetary loading is investigated using an analytical model for determining the stresses in an arbitrarily thick spherical shell due to an idealized axisymmetric load. The model includes the flat plate and thin shell membrane approximations as end members, and makes it possible to determine the nature of the transition between them. Using this model, the stress states and the resulting tectonic patterns due to an idealized exponential load are determined as functions of five dimensionless parameters: the ratio of the lithospheric thickness to the planetary radius; the decay width of the load; the 'support parameter', which is the ratio of the buoyancy to the flexural support; the angular distance from the load center; and the normalized radial distance from the planet center.

  9. Truck loading rack blending

    SciTech Connect

    Boubenider, E.

    1995-12-01

    Blending, the combining of two or more components to make a single product, has become widely used in most loading rack applications. Blending should not be confused with additive injection, which is the injection of very small doses of enhancers, detergents and dyes into a product stream. Changes in the environmental protection laws in the early 90`s have put increasing demands on marketing terminals with regards to reformulated fuels and environmental protection concerns. As a result of these new mandates, terminals have turned to blending at the loading rack as an economical and convenient means in meeting these new requirements. This paper will discuss some of these mandates and how loading rack blending is used for different applications. Various types of blending will also be discussed along with considerations for each method.

  10. Elastomeric load sharing device

    NASA Technical Reports Server (NTRS)

    Isabelle, Charles J. (Inventor); Kish, Jules G. (Inventor); Stone, Robert A. (Inventor)

    1992-01-01

    An elastomeric load sharing device, interposed in combination between a driven gear and a central drive shaft to facilitate balanced torque distribution in split power transmission systems, includes a cylindrical elastomeric bearing and a plurality of elastomeric bearing pads. The elastomeric bearing and bearing pads comprise one or more layers, each layer including an elastomer having a metal backing strip secured thereto. The elastomeric bearing is configured to have a high radial stiffness and a low torsional stiffness and is operative to radially center the driven gear and to minimize torque transfer through the elastomeric bearing. The bearing pads are configured to have a low radial and torsional stiffness and a high axial stiffness and are operative to compressively transmit torque from the driven gear to the drive shaft. The elastomeric load sharing device has spring rates that compensate for mechanical deviations in the gear train assembly to provide balanced torque distribution between complementary load paths of split power transmission systems.

  11. Shuttle car loading system

    NASA Technical Reports Server (NTRS)

    Collins, E. R., Jr. (Inventor)

    1985-01-01

    A system is described for loading newly mined material such as coal, into a shuttle car, at a location near the mine face where there is only a limited height available for a loading system. The system includes a storage bin having several telescoping bin sections and a shuttle car having a bottom wall that can move under the bin. With the bin in an extended position and filled with coal the bin sections can be telescoped to allow the coal to drop out of the bin sections and into the shuttle car, to quickly load the car. The bin sections can then be extended, so they can be slowly filled with more while waiting another shuttle car.

  12. Microbial load monitor

    NASA Technical Reports Server (NTRS)

    Caplin, R. S.; Royer, E. R.

    1978-01-01

    Attempts are made to provide a total design of a Microbial Load Monitor (MLM) system flight engineering model. Activities include assembly and testing of Sample Receiving and Card Loading Devices (SRCLDs), operator related software, and testing of biological samples in the MLM. Progress was made in assembling SRCLDs with minimal leaks and which operate reliably in the Sample Loading System. Seven operator commands are used to control various aspects of the MLM such as calibrating and reading the incubating reading head, setting the clock and reading time, and status of Card. Testing of the instrument, both in hardware and biologically, was performed. Hardware testing concentrated on SRCLDs. Biological testing covered 66 clinical and seeded samples. Tentative thresholds were set and media performance listed.

  13. Residential load profiles for photovoltaic simulation studies

    NASA Astrophysics Data System (ADS)

    Rudisill, J. F.; Lathrop, J. W.

    In order to analyze the performance of photovoltaic (PV) systems in residential applications, it is necessary to consider the load characteristics. This paper describes a computer based model which simulates the demand of a 'typical' residential customer. Input parameters allow the model to be customized for different lifestyles and different geographical locations. Previous research has utilized hourly intervals of the time domain, based on utility averages. Since the electrical demand (and solar supply) can change instantaneously, the continuous time feature is necessary in order to accurately analyze the effect of various load management strategies. The residential load was divided into heating-ventilating-air conditioning, water heating, and diversified components. The model incorporates the interactive effects of the three components as well as temporal, meteorological, and geographic effects.

  14. The Effects of Load Distribution and Gradient on Load Carriage

    DTIC Science & Technology

    2010-12-01

    Postural adjustments while standing with two types of loaded backpack. Ergonomics, 30(10), 1425–1430. Bobet, J. & Norman, R. W. (1984). Effects of...Danise, B., Milanese, S., Pirunsan, U., & Trott, P. (2002). Adolescent standing postural response to backpack loads: a randomized controlled...loads are authorized. Numerous studies conclude that backpack loads have a huge impact on soldiers’ load carrying ability. The platoon’s combat

  15. Ocean Tide Loading Computation

    NASA Technical Reports Server (NTRS)

    Agnew, Duncan Carr

    2005-01-01

    September 15,2003 through May 15,2005 This grant funds the maintenance, updating, and distribution of programs for computing ocean tide loading, to enable the corrections for such loading to be more widely applied in space- geodetic and gravity measurements. These programs, developed under funding from the CDP and DOSE programs, incorporate the most recent global tidal models developed from Topex/Poscidon data, and also local tide models for regions around North America; the design of the algorithm and software makes it straightforward to combine local and global models.

  16. Reconstruction of Orion Engineering Development Unit (EDU) Parachute Inflation Loads

    NASA Technical Reports Server (NTRS)

    Ray, Eric S.

    2013-01-01

    The process of reconstructing inflation loads of Capsule Parachute Assembly System (CPAS) has been updated as the program transitioned to testing Engineering Development Unit (EDU) hardware. The equations used to reduce the test data have been re-derived based on the same physical assumptions made by simulations. Due to instrumentation challenges, individual parachute loads are determined from complementary accelerometer and load cell measurements. Cluster inflations are now simulated by modeling each parachute individually to better represent different inflation times and non-synchronous disreefing. The reconstruction procedure is tailored to either infinite mass or finite mass events based on measurable characteristics from the test data. Inflation parameters are determined from an automated optimization routine to reduce subjectivity. Infinite mass inflation parameters have been re-defined to avoid unrealistic interactions in Monte Carlo simulations. Sample cases demonstrate how best-fit inflation parameters are used to generate simulated drag areas and loads which favorably agree with test data.

  17. Transfer Mechanisms for Heavy Loads

    NASA Technical Reports Server (NTRS)

    Cassisi, V.

    1986-01-01

    Soft hydraulic system gently maneuvers loads. Upper and lower load-transfer mechanisms attach through mounting holes in vertical beam adjustable or gross positioning. Fine positioning of load accomplished by hydraulic cylinders that move trunnion support and trunnion clamp through short distances. Useful in transferring large loads in railroads, agriculture, shipping, manufacturing, and even precision assembly of large items.

  18. Five-Parameter Bivariate Probability Distribution

    NASA Technical Reports Server (NTRS)

    Tubbs, J.; Brewer, D.; Smith, O. W.

    1986-01-01

    NASA technical memorandum presents four papers about five-parameter bivariate gamma class of probability distributions. With some overlap of subject matter, papers address different aspects of theories of these distributions and use in forming statistical models of such phenomena as wind gusts. Provides acceptable results for defining constraints in problems designing aircraft and spacecraft to withstand large wind-gust loads.

  19. Dynamic Strength Ceramic Nanocomposites Under Pulse Loading

    NASA Astrophysics Data System (ADS)

    Skripnyak, Evgeniya G.; Skripnyak, Vladimir V.; Vaganova, Irina K.; Skripnyak, Vladimir A.

    2015-06-01

    Multi-scale computer simulation approach has been applied to research of strength of nanocomposites under dynamic loading. The influence of mesoscopic substructures on the dynamic strength of ceramic and hybrid nanocomposites, which can be formed using additive manufacturing were numerically investigated. At weak shock wave loadings the shear strength and the spall strength of ceramic and hybrid nanocomposites depends not only phase concentration and porosity, but size parameters of skeleton substructures. The influence of skeleton parameter on the shear strength and the spall strength of ceramic nanocomposites with the same concentration of phases decreases with increasing amplitude of the shock pulse of microsecond duration above the double amplitude of the Hugoniot elastic limit of nanocomposites. This research carried out in 2014 -2015 was supported by grant from The Tomsk State University Academic D.I. Mendeleev Fund Program and also Ministry of Sciences and Education of Russian Federation (State task 2014/223, project 1943, Agreement 14.132.

  20. LOADING AND UNLOADING DEVICE

    DOEpatents

    Treshow, M.

    1960-08-16

    A device for loading and unloading fuel rods into and from a reactor tank through an access hole includes parallel links carrying a gripper. These links enable the gripper to go through the access hole and then to be moved laterally from the axis of the access hole to the various locations of the fuel rods in the reactor tank.

  1. Multidimensional spectral load balancing

    DOEpatents

    Hendrickson, Bruce A.; Leland, Robert W.

    1996-12-24

    A method of and apparatus for graph partitioning involving the use of a plurality of eigenvectors of the Laplacian matrix of the graph of the problem for which load balancing is desired. The invention is particularly useful for optimizing parallel computer processing of a problem and for minimizing total pathway lengths of integrated circuits in the design stage.

  2. Load research manual. Volume 1. Load research procedures

    SciTech Connect

    Brandenburg, L.; Clarkson, G.; Grund, Jr., C.; Leo, J.; Asbury, J.; Brandon-Brown, F.; Derderian, H.; Mueller, R.; Swaroop, R.

    1980-11-01

    This three-volume manual presents technical guidelines for electric utility load research. Special attention is given to issues raised by the load data reporting requirements of the Public Utility Regulatory Policies Act of 1978 and to problems faced by smaller utilities that are initiating load research programs. In Volumes 1 and 2, procedures are suggested for determining data requirements for load research, establishing the size and customer composition of a load survey sample, selecting and using equipment to record customer electricity usage, processing data tapes from the recording equipment, and analyzing the data. Statistical techniques used in customer sampling are discussed in detail. The costs of load research also are estimated, and ongoing load research programs at three utilities are described. The manual includes guides to load research literature and glossaries of load research and statistical terms.

  3. Measuring alignment of loading fixture

    DOEpatents

    Scavone, Donald W.

    1989-01-01

    An apparatus and method for measuring the alignment of a clevis and pin type loading fixture for compact tension specimens include a pair of substantially identical flat loading ligaments. Each loading ligament has two apertures for the reception of a respective pin of the loading fixture and a thickness less than one-half of a width of the clevis opening. The pair of loading ligaments are mounted in the clevis openings at respective sides thereof. The loading ligaments are then loaded by the pins of the loading fixture and the strain in each loading ligament is measured. By comparing the relative strain of each loading ligament, the alignment of the loading fixture is determined. Preferably, a suitable strain gage device is located at each longitudinal edge of a respective loading ligament equidistant from the two apertures in order to determine the strain thereat and hence the strain of each ligament. The loading ligaments are made substantially identical by jig grinding the loading ligaments as a matched set. Each loading ligament can also be individually calibrated prior to the measurement.

  4. CHOICE OF PROTON DRIVER PARAMETERS FOR A NEUTRINO FACTORY.

    SciTech Connect

    KIRK, H.G.; BERG, J.S.; FERNOW, R.C.; GALLARDO, J.C.; SIMOS, N.; WENG, W.

    2006-06-23

    We discuss criteria for designing an optimal ''green field'' proton driver for a neutrino factory. The driver parameters are determined by considerations of space charge, power capabilities of the target, beam loading and available RF peak power.

  5. Load controller and method to enhance effective capacity of a photovoltaic power supply

    DOEpatents

    Perez, Richard

    2000-01-01

    A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply. The renewable supply may comprise, for example, a photovoltaic power supply or a wind-based power supply.

  6. Modeling Aircraft Wing Loads from Flight Data Using Neural Networks

    NASA Technical Reports Server (NTRS)

    Allen, Michael J.; Dibley, Ryan P.

    2003-01-01

    Neural networks were used to model wing bending-moment loads, torsion loads, and control surface hinge-moments of the Active Aeroelastic Wing (AAW) aircraft. Accurate loads models are required for the development of control laws designed to increase roll performance through wing twist while not exceeding load limits. Inputs to the model include aircraft rates, accelerations, and control surface positions. Neural networks were chosen to model aircraft loads because they can account for uncharacterized nonlinear effects while retaining the capability to generalize. The accuracy of the neural network models was improved by first developing linear loads models to use as starting points for network training. Neural networks were then trained with flight data for rolls, loaded reversals, wind-up-turns, and individual control surface doublets for load excitation. Generalization was improved by using gain weighting and early stopping. Results are presented for neural network loads models of four wing loads and four control surface hinge moments at Mach 0.90 and an altitude of 15,000 ft. An average model prediction error reduction of 18.6 percent was calculated for the neural network models when compared to the linear models. This paper documents the input data conditioning, input parameter selection, structure, training, and validation of the neural network models.

  7. Load measurement system with load cell lock-out mechanism

    NASA Technical Reports Server (NTRS)

    Le, Thang; Carroll, Monty; Liu, Jonathan

    1995-01-01

    In the frame work of the project Shuttle Plume Impingement Flight Experiment (SPIFEX), a Load Measurement System was developed and fabricated to measure the impingement force of Shuttle Reaction Control System (RCS) jets. The Load Measurement System is a force sensing system that measures any combination of normal and shear forces up to 40 N (9 lbf) in the normal direction and 22 N (5 lbf) in the shear direction with an accuracy of +/- 0.04 N (+/- 0.01 lbf) Since high resolution is required for the force measurement, the Load Measurement System is built with highly sensitive load cells. To protect these fragile load cells in the non-operational mode from being damaged due to flight loads such as launch and landing loads of the Shuttle vehicle, a motor driven device known as the Load Cell Lock-Out Mechanism was built. This Lock-Out Mechanism isolates the load cells from flight loads and re-engages the load cells for the force measurement experiment once in space. With this highly effective protection system, the SPIFEX load measurement experiment was successfully conducted on STS-44 in September 1994 with all load cells operating properly and reading impingement forces as expected.

  8. Electrical Load Modeling and Simulation

    SciTech Connect

    Chassin, David P.

    2013-01-01

    Electricity consumer demand response and load control are playing an increasingly important role in the development of a smart grid. Smart grid load management technologies such as Grid FriendlyTM controls and real-time pricing are making their way into the conventional model of grid planning and operations. However, the behavior of load both affects, and is affected by load control strategies that are designed to support electric grid planning and operations. This chapter discussed the natural behavior of electric loads, how it interacts with various load control and demand response strategies, what the consequences are for new grid operation concepts and the computing issues these new technologies raise.

  9. 32. VAL, DETAIL SHOWING LOADING PLATFORM, PROJECTILE LOADING CAR, LAUNCHER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. VAL, DETAIL SHOWING LOADING PLATFORM, PROJECTILE LOADING CAR, LAUNCHER SLAB AND UNDERSIDE OF LAUNCHER BRIDGE LOOKING SOUTHWEST. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  10. Shot loading trainer analysis

    SciTech Connect

    Peterson, T.K.

    1995-02-15

    This document presents the results from the analysis of the shot loading trainer (SLT). This device will be used to test the procedure for installing shot into the annulus of the Project W-320 shipping container. To ensure that the shot is installed uniformly around the container, vibrators will be used to settle the shot. The SLT was analyzed to ensure that it would not jeopardize worker safety during operation. The results from the static analysis of the SLT under deadweight and vibrator operating loads show that the stresses in the SLT are below code allowables. The results from the modal analysis show that the natural frequencies of the SLT are far below the operating frequencies of the vibrators, provided the SLT is mounted on pneumatic tires. The SLT was also analyzed for wind, seismic, deadweight, and moving/transporting loads. Analysis of the SLT is in accordance with SDC-4.1 for safety class 3 structures (DOE-RL 1993) and the American Institute of Steel Construction (AISC) Manual of Steel Construction (AISC 1989).

  11. Buffet Load Alleviation

    NASA Technical Reports Server (NTRS)

    Ryall, T. G.; Moses, R. W.; Hopkins, M. A.; Henderson, D.; Zimcik, D. G.; Nitzsche, F.

    2004-01-01

    High performance aircraft are, by their very nature, often required to undergo maneuvers involving high angles of attack. Under these conditions unsteady vortices emanating from the wing and the fuselage will impinge on the twin fins (required for directional stability) causing excessive buffet loads, in some circumstances, to be applied to the aircraft. These loads result in oscillatory stresses, which may cause significant amounts of fatigue damage. Active control is a possible solution to this important problem. A full-scale test was carried out on an F/A-18 fuselage and fins using piezoceramic actuators to control the vibrations. Buffet loads were simulated using very powerful electromagnetic shakers. The first phase of this test was concerned with the open loop system identification whereas the second stage involved implementing linear time invariant control laws. This paper looks at some of the problems encountered as well as the corresponding solutions and some results. It is expected that flight trials of a similar control system to alleviate buffet will occur as early as 2001.

  12. Load regulating latch

    NASA Technical Reports Server (NTRS)

    Appleberry, W. T. (Inventor)

    1977-01-01

    A load regulating mechanical latch is described that has a pivotally mounted latch element having a hook-shaped end with a strike roller-engaging laterally open hook for engaging a stationary strike roller. The latch element or hook is pivotally mounted in a clevis end of an elongated latch stem that is adapted for axial movement through an opening in a support plate or bracket mounted to a structural member. A coil spring is disposed over and around the extending latch stem and the lower end of the coil spring engages the support bracket. A thrust washer is removably attached to the other end of the latch stem and engages the other end of the coil spring and compresses the coil spring thereby preloading the spring and the latch element carried by the latch stem. The hook-shaped latch element has a limited degree of axial travel for loading caused by structural distortion which may change the relative positions of the latch element hook and the strike roller. Means are also provided to permit limited tilt of the latch element due to loading of the hook.

  13. Load responsive hydrodynamic bearing

    DOEpatents

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  14. Elevated Temperature Slow Crack Growth of Silicon Nitride Under Dynamic, Static and Cyclic Flexural Loading

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Salem, Jonathan A.; Nemeth, Noel; Gyekenyesi, John P.

    1994-01-01

    The slow crack growth parameters of a hot-pressed silicon nitride were determined at 1200 and 1300 C in air by statically, dynamically and cyclicly loading bend specimens. The fatigue parameters were estimated using the recently developed CARES/Life computer code. Good agreement exists between the flexural results. However, fatigue susceptibility under static uniaxial tensile loading, reported elsewhere, was greater than in flexure. Cyclic flexural loading resulted in the lowest apparent flexural fatigue susceptibility.

  15. Flow processes in overexpanded chemical rocket nozzles. Part 2: Side loads due to asymmetric separation

    NASA Technical Reports Server (NTRS)

    Schmucker, R. H.

    1984-01-01

    Methods for measuring the lateral forces, occurring as a result of asymmetric nozzle flow separation, are discussed. The effect of some parameters on the side load is explained. A new method was developed for calculation of the side load. The values calculated are compared with side load data of the J-2 engine. Results are used for predicting side loads of the space shuttle main engine.

  16. Mechanical loading, damping, and load-driven bone formation in mouse tibiae.

    PubMed

    Dodge, Todd; Wanis, Mina; Ayoub, Ramez; Zhao, Liming; Watts, Nelson B; Bhattacharya, Amit; Akkus, Ozan; Robling, Alexander; Yokota, Hiroki

    2012-10-01

    Mechanical loads play a pivotal role in the growth and maintenance of bone and joints. Although loading can activate anabolic genes and induce bone remodeling, damping is essential for preventing traumatic bone injury and fracture. In this study we investigated the damping capacity of bone, joint tissue, muscle, and skin using a mouse hindlimb model of enhanced loading in conjunction with finite element modeling to model bone curvature. Our hypothesis was that loads were primarily absorbed by the joints and muscle tissue, but that bone also contributed to damping through its compression and natural bending. To test this hypothesis, fresh mouse distal lower limb segments were cyclically loaded in axial compression in sequential bouts, with each subsequent bout having less surrounding tissue. A finite element model was generated to model effects of bone curvature in silico. Two damping-related parameters (phase shift angle and energy loss) were determined from the output of the loading experiments. Interestingly, the experimental results revealed that the knee joint contributed to the largest portion of the damping capacity of the limb, and bone itself accounted for approximately 38% of the total phase shift angle. Computational results showed that normal bone curvature enhanced the damping capacity of the bone by approximately 40%, and the damping effect grew at an accelerated pace as curvature was increased. Although structural curvature reduces critical loads for buckling in beam theory, evolution apparently favors maintaining curvature in the tibia. Histomorphometric analysis of the tibia revealed that in response to axial loading, bone formation was significantly enhanced in the regions that were predicted to receive a curvature-induced bending moment. These results suggest that in addition to bone's compressive damping capacity, surrounding tissues, as well as naturally-occurring bone curvature, also contribute to mechanical damping, which may ultimately affect

  17. Variable loading roller

    DOEpatents

    Williams, D.M.

    1988-01-21

    An automatic loading roller for transmitting torque in traction drive devices in manipulator arm joints includes a two-part camming device having a first cam portion rotatable in place on a shaft by an input torque and a second cam portion coaxially rotatable and translatable having a rotating drive surface thereon for engaging the driven surface of an output roller with a resultant force proportional to the torque transmitted. Complementary helical grooves in the respective cam portions interconnected through ball bearings interacting with those grooves effect the rotation and translation of the second cam portion in response to rotation of the first. 14 figs.

  18. Multidimensional spectral load balancing

    SciTech Connect

    Hendrickson, B.; Leland, R.

    1993-01-01

    We describe an algorithm for the static load balancing of scientific computations that generalizes and improves upon spectral bisection. Through a novel use of multiple eigenvectors, our new spectral algorithm can divide a computation into 4 or 8 pieces at once. These multidimensional spectral partitioning algorithms generate balanced partitions that have lower communication overhead and are less expensive to compute than those produced by spectral bisection. In addition, they automatically work to minimize message contention on a hypercube or mesh architecture. These spectral partitions are further improved by a multidimensional generalization of the Kernighan-Lin graph partitioning algorithm. Results on several computational grids are given and compared with other popular methods.

  19. Microbial Load Monitor

    NASA Technical Reports Server (NTRS)

    Gibson, S. F.; Royer, E. R.

    1979-01-01

    The Microbial Load Monitor (MLM) is an automated and computerized system for detection and identification of microorganisms. Additionally, the system is designed to enumerate and provide antimicrobic susceptibility profiles for medically significant bacteria. The system is designed to accomplish these tasks in a time of 13 hours or less versus the traditional time of 24 hours for negatives and 72 hours or more for positives usually required for standard microbiological analysis. The MLM concept differs from other methods of microbial detection in that the system is designed to accept raw untreated clinical samples and to selectively identify each group or species that may be present in a polymicrobic sample.

  20. Plug Loads Conservation Measures

    SciTech Connect

    Ian Metzger, Jesse Dean

    2010-12-31

    This software requires inputs of simple plug loads inventory information and calculates the energy and cost benefits of various retrofit opportunities. This tool includes energy conservation measures for: Vending Machine Misers, Delamp Vending Machine, Desktop to Laptop retrofit, CRT to LCD monitors retrofit, Computer Power Management Settings, and Energy Star Refrigerator retrofit. This tool calculates energy savings, demand reduction, cost savings, building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.

  1. Variable loading roller

    DOEpatents

    Williams, Daniel M.

    1989-01-01

    An automatic loading roller for transmitting torque in traction drive devices in manipulator arm joints includes a two-part camming device having a first cam portion rotatable in place on a shaft by an input torque and a second cam portion coaxially rotatable and translatable having a rotating drive surface thereon for engaging the driven surface of an output roller with a resultant force proportional to the torque transmitted. Complementary helical grooves on the respective cam portions interconnected through ball bearings interacting with those grooves effect the rotation and translation of the second cam portion in response to rotation of the first.

  2. Some properties of a 5-parameter bivariate probability distribution

    NASA Technical Reports Server (NTRS)

    Tubbs, J. D.; Brewer, D. W.; Smith, O. E.

    1983-01-01

    A five-parameter bivariate gamma distribution having two shape parameters, two location parameters and a correlation parameter was developed. This more general bivariate gamma distribution reduces to the known four-parameter distribution. The five-parameter distribution gives a better fit to the gust data. The statistical properties of this general bivariate gamma distribution and a hypothesis test were investigated. Although these developments have come too late in the Shuttle program to be used directly as design criteria for ascent wind gust loads, the new wind gust model has helped to explain the wind profile conditions which cause large dynamic loads. Other potential applications of the newly developed five-parameter bivariate gamma distribution are in the areas of reliability theory, signal noise, and vibration mechanics.

  3. Characterization of cephalexin loaded nonionic microemulsions.

    PubMed

    Fanun, Monzer; Papadimitriou, Vassiliki; Xenakis, Aristotelis

    2011-09-01

    Water/propylene glycol/sucrose laurate/ethoxylated mono-di-glyceride/isopropyl myristate/peppermint oil U-type microemulsions were used to solubilize cephalexin. Microemulsion dilution and interfacial factors contributing to the cephalexin solubilization were evaluated. Cephalexin solubilization capacity increases with the increase in the aqueous phase volume fraction (φ) up to 0.4 then decreases. Electrical conductivity of drug loaded and drug free microemulsions increases with φ. The hydrodynamic radius measured by dynamic light scattering of the oil-in-water loaded microemulsions decreases with temperature. The microemulsions were characterized by the volumetric parameters, density, excess volume, ultrasonic velocity and isentropic compressibility. The microemulsion densities increase with φ up to 0.8 then decrease. The excess volume decreases with φ up to 0.8 then stabilizes. Ultrasonic velocities increase with the increase in φ while isentropic compressibility decreases. Analysis of the volumetric parameters enabled the characterization of structural transition along the microemulsion phase region. The presence of water-in-oil, bicontinuous and oil-in-water microemulsions, at aqueous phase volume fractions below 0.2, between 0.3 and 0.7 and above 0.8, respectively were found. Interfacial properties and dynamic structure of the monolayer for drug loaded and drug free microemulsions, were studied by electron paramagnetic resonance spectroscopy employing the nitroxide spin probe 5-doxylstearic acid. The rigidity of the interface was affected by the water content and also the presence of cephalexin.

  4. Load Component Database of Household Appliances and Small Office Equipment

    SciTech Connect

    Lu, Ning; Xie, YuLong; Huang, Zhenyu; Puyleart, Francis; Yang, Steve

    2008-07-24

    This paper discusses the development of a load component database for household appliances and office equipment. To develop more accurate load models at both transmission and distribution level, a better understanding on the individual behaviors of home appliances and office equipment under power system voltage and frequency variations becomes more and more critical. Bonneville Power Administration (BPA) has begun a series of voltage and frequency tests against home appliances and office equipments since 2005. Since 2006, Researchers at Pacific Northwest National Laboratory has collaborated with BPA personnel and developed a load component database based on these appliance testing results to facilitate the load model validation work for the Western Electricity Coordinating Council (WECC). In this paper, the testing procedure and testing results are first presented. The load model parameters are then derived and grouped. Recommendations are given for aggregating the individual appliance models to feeder level, the models of which are used for distribution and transmission level studies.

  5. Load Diffusion in Composite and Smart Structures

    NASA Technical Reports Server (NTRS)

    Horgan, Cornelius O.; Ambur, D. (Technical Monitor); Nemeth, M. P. (Technical Monitor)

    2003-01-01

    The research carried out here builds on our previous NASA supported research on the general topic of edge effects and load diffusion in composite structures. Further fundamental solid mechanics studies were carried out to provide a basis for assessing the complicated modeling necessary for the multi-functional large scale structures used by NASA. An understanding of the fundamental mechanisms of load diffusion in composite subcomponents is essential in developing primary composite structures. Some specific problems recently considered were those of end effects in smart materials and structures, study of the stress response of pressurized linear piezoelectric cylinders for both static and steady rotating configurations, an analysis of the effect of pre-stressing and pre-polarization on the decay of end effects in piezoelectric solids and investigation of constitutive models for hardening rubber-like materials. Our goal in the study of load diffusion is the development of readily applicable results for the decay lengths in terms of non-dimensional material and geometric parameters. Analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and assessing results from finite element analyses.

  6. Redefining solubility parameters: the partial solvation parameters.

    PubMed

    Panayiotou, Costas

    2012-03-21

    The present work reconsiders a classical and universally accepted concept of physical chemistry, the solubility parameter. Based on the insight derived from modern quantum chemical calculations, a new definition of solubility parameter is proposed, which overcomes some of the inherent restrictions of the original definition and expands its range of applications. The original single solubility parameter is replaced by four partial solvation parameters reflecting the dispersion, the polar, the acidic and the basic character of the chemical compounds as expressed either in their pure state or in mixtures. Simple rules are adopted for the definition and calculation of these four parameters and their values are tabulated for a variety of common substances. In contrast, however, to the well known Hansen solubility parameters, their design and evaluation does not rely exclusively on the basic rule of "similarity matching" for solubility but it makes also use of the other basic rule of compatibility, namely, the rule of "complementarity matching". This complementarity matching becomes particularly operational with the sound definition of the acidic and basic components of the solvation parameter based on the third σ-moments of the screening charge distributions of the quantum mechanics-based COSMO-RS theory. The new definitions are made in a simple and straightforward manner, thus, preserving the strength and appeal of solubility parameter stemming from its simplicity. The new predictive method has been applied to a variety of solubility data for systems of pharmaceuticals and polymers. The results from quantum mechanics calculations are critically compared with the results from Abraham's acid/base descriptors.

  7. Design of a biaxial mechanical loading bioreactor for tissue engineering.

    PubMed

    Bilgen, Bahar; Chu, Danielle; Stefani, Robert; Aaron, Roy K

    2013-04-25

    We designed a loading device that is capable of applying uniaxial or biaxial mechanical strain to a tissue engineered biocomposites fabricated for transplantation. While the device primarily functions as a bioreactor that mimics the native mechanical strains, it is also outfitted with a load cell for providing force feedback or mechanical testing of the constructs. The device subjects engineered cartilage constructs to biaxial mechanical loading with great precision of loading dose (amplitude and frequency) and is compact enough to fit inside a standard tissue culture incubator. It loads samples directly in a tissue culture plate, and multiple plate sizes are compatible with the system. The device has been designed using components manufactured for precision-guided laser applications. Bi-axial loading is accomplished by two orthogonal stages. The stages have a 50 mm travel range and are driven independently by stepper motor actuators, controlled by a closed-loop stepper motor driver that features micro-stepping capabilities, enabling step sizes of less than 50 nm. A polysulfone loading platen is coupled to the bi-axial moving platform. Movements of the stages are controlled by Thor-labs Advanced Positioning Technology (APT) software. The stepper motor driver is used with the software to adjust load parameters of frequency and amplitude of both shear and compression independently and simultaneously. Positional feedback is provided by linear optical encoders that have a bidirectional repeatability of 0.1 μm and a resolution of 20 nm, translating to a positional accuracy of less than 3 μm over the full 50 mm of travel. These encoders provide the necessary position feedback to the drive electronics to ensure true nanopositioning capabilities. In order to provide the force feedback to detect contact and evaluate loading responses, a precision miniature load cell is positioned between the loading platen and the moving platform. The load cell has high accuracies of 0

  8. Design of a Biaxial Mechanical Loading Bioreactor for Tissue Engineering

    PubMed Central

    Bilgen, Bahar; Chu, Danielle; Stefani, Robert; Aaron, Roy K.

    2013-01-01

    We designed a loading device that is capable of applying uniaxial or biaxial mechanical strain to a tissue engineered biocomposites fabricated for transplantation. While the device primarily functions as a bioreactor that mimics the native mechanical strains, it is also outfitted with a load cell for providing force feedback or mechanical testing of the constructs. The device subjects engineered cartilage constructs to biaxial mechanical loading with great precision of loading dose (amplitude and frequency) and is compact enough to fit inside a standard tissue culture incubator. It loads samples directly in a tissue culture plate, and multiple plate sizes are compatible with the system. The device has been designed using components manufactured for precision-guided laser applications. Bi-axial loading is accomplished by two orthogonal stages. The stages have a 50 mm travel range and are driven independently by stepper motor actuators, controlled by a closed-loop stepper motor driver that features micro-stepping capabilities, enabling step sizes of less than 50 nm. A polysulfone loading platen is coupled to the bi-axial moving platform. Movements of the stages are controlled by Thor-labs Advanced Positioning Technology (APT) software. The stepper motor driver is used with the software to adjust load parameters of frequency and amplitude of both shear and compression independently and simultaneously. Positional feedback is provided by linear optical encoders that have a bidirectional repeatability of 0.1 μm and a resolution of 20 nm, translating to a positional accuracy of less than 3 μm over the full 50 mm of travel. These encoders provide the necessary position feedback to the drive electronics to ensure true nanopositioning capabilities. In order to provide the force feedback to detect contact and evaluate loading responses, a precision miniature load cell is positioned between the loading platen and the moving platform. The load cell has high accuracies of 0

  9. Load Control System Reliability

    SciTech Connect

    Trudnowski, Daniel

    2015-04-03

    This report summarizes the results of the Load Control System Reliability project (DOE Award DE-FC26-06NT42750). The original grant was awarded to Montana Tech April 2006. Follow-on DOE awards and expansions to the project scope occurred August 2007, January 2009, April 2011, and April 2013. In addition to the DOE monies, the project also consisted of matching funds from the states of Montana and Wyoming. Project participants included Montana Tech; the University of Wyoming; Montana State University; NorthWestern Energy, Inc., and MSE. Research focused on two areas: real-time power-system load control methodologies; and, power-system measurement-based stability-assessment operation and control tools. The majority of effort was focused on area 2. Results from the research includes: development of fundamental power-system dynamic concepts, control schemes, and signal-processing algorithms; many papers (including two prize papers) in leading journals and conferences and leadership of IEEE activities; one patent; participation in major actual-system testing in the western North American power system; prototype power-system operation and control software installed and tested at three major North American control centers; and, the incubation of a new commercial-grade operation and control software tool. Work under this grant certainly supported the DOE-OE goals in the area of “Real Time Grid Reliability Management.”

  10. Shuttle propellant loading instrumenation development

    NASA Technical Reports Server (NTRS)

    Hamlet, J.

    1975-01-01

    A continuous capacitance sensor was developed and an analog signal conditioner was evaluated to demonstrate the acceptability of these items for use in the space shuttle propellant loading system. An existing basic sensor concept was redesigned to provide capability for cryogenic operation, to improve performance, and to minimize production costs. Sensor development verification consisted of evaluation of sensor linearity, cryogenic performance, and stability during vibration. The signal conditioner evaluation consisted mainly of establishing the effects of the variations in temperature and cable parameters and evaluating the stability. A sensor linearity of 0.04 in. was achieved over most of the sensor length. The sensor instability caused by vibration was 0.04 percent. The cryogenic performance data show a maximum instability of 0.19 percent at liquid hydrogen temperature; a theoretical calibration can be computed a within 1 percent. The signal conditioner evaluation showed that, with temperature compensation, all error sources typically contribute much less than 1 percent. An estimate of the accuracy achievable with the sensor and signal conditioner shows an rss estimate of 0.75 in. for liquid oxygen and 1.02 in. for liquid hydrogen. These are approximately four times better than the shuttle requirements. Comparison of continuous sensor and discrete sensor performance show the continuous sensor to be significantly better when there is surface activity due to sloshing, boiling, or other disturbances.

  11. Respiratory Changes in Response to Cognitive Load: A Systematic Review

    PubMed Central

    Grassmann, Mariel; Vlemincx, Elke; von Leupoldt, Andreas; Mittelstädt, Justin M.

    2016-01-01

    When people focus attention or carry out a demanding task, their breathing changes. But which parameters of respiration vary exactly and can respiration reliably be used as an index of cognitive load? These questions are addressed in the present systematic review of empirical studies investigating respiratory behavior in response to cognitive load. Most reviewed studies were restricted to time and volume parameters while less established, yet meaningful parameters such as respiratory variability have rarely been investigated. The available results show that respiratory behavior generally reflects cognitive processing and that distinct parameters differ in sensitivity: While mentally demanding episodes are clearly marked by faster breathing and higher minute ventilation, respiratory amplitude appears to remain rather stable. The present findings further indicate that total variability in respiratory rate is not systematically affected by cognitive load whereas the correlated fraction decreases. In addition, we found that cognitive load may lead to overbreathing as indicated by decreased end-tidal CO2 but is also accompanied by elevated oxygen consumption and CO2 release. However, additional research is needed to validate the findings on respiratory variability and gas exchange measures. We conclude by outlining recommendations for future research to increase the current understanding of respiration under cognitive load. PMID:27403347

  12. Ozone depletion and chlorine loading potentials

    NASA Technical Reports Server (NTRS)

    Pyle, John A.; Wuebbles, Donald J.; Solomon, Susan; Zvenigorodsky, Sergei; Connell, Peter; Ko, Malcolm K. W.; Fisher, Donald A.; Stordal, Frode; Weisenstein, Debra

    1991-01-01

    The recognition of the roles of chlorine and bromine compounds in ozone depletion has led to the regulation or their source gases. Some source gases are expected to be more damaging to the ozone layer than others, so that scientific guidance regarding their relative impacts is needed for regulatory purposes. Parameters used for this purpose include the steady-state and time-dependent chlorine loading potential (CLP) and the ozone depletion potential (ODP). Chlorine loading potentials depend upon the estimated value and accuracy of atmospheric lifetimes and are subject to significant (approximately 20-50 percent) uncertainties for many gases. Ozone depletion potentials depend on the same factors, as well as the evaluation of the release of reactive chlorine and bromine from each source gas and corresponding ozone destruction within the stratosphere.

  13. Parameter Estimation of Partial Differential Equation Models.

    PubMed

    Xun, Xiaolei; Cao, Jiguo; Mallick, Bani; Carroll, Raymond J; Maity, Arnab

    2013-01-01

    Partial differential equation (PDE) models are commonly used to model complex dynamic systems in applied sciences such as biology and finance. The forms of these PDE models are usually proposed by experts based on their prior knowledge and understanding of the dynamic system. Parameters in PDE models often have interesting scientific interpretations, but their values are often unknown, and need to be estimated from the measurements of the dynamic system in the present of measurement errors. Most PDEs used in practice have no analytic solutions, and can only be solved with numerical methods. Currently, methods for estimating PDE parameters require repeatedly solving PDEs numerically under thousands of candidate parameter values, and thus the computational load is high. In this article, we propose two methods to estimate parameters in PDE models: a parameter cascading method and a Bayesian approach. In both methods, the underlying dynamic process modeled with the PDE model is represented via basis function expansion. For the parameter cascading method, we develop two nested levels of optimization to estimate the PDE parameters. For the Bayesian method, we develop a joint model for data and the PDE, and develop a novel hierarchical model allowing us to employ Markov chain Monte Carlo (MCMC) techniques to make posterior inference. Simulation studies show that the Bayesian method and parameter cascading method are comparable, and both outperform other available methods in terms of estimation accuracy. The two methods are demonstrated by estimating parameters in a PDE model from LIDAR data.

  14. Structural Design Parameters for Germanium

    NASA Technical Reports Server (NTRS)

    Salem, Jon; Rogers, Richard; Baker, Eric

    2017-01-01

    The fracture toughness and slow crack growth parameters of germanium supplied as single crystal beams and coarse grain disks were measured. Although germanium is anisotropic (A* 1.7), it is not as anisotropic as SiC, NiAl, or Cu. Thus the fracture toughness was similar on the 100, 110, and 111 planes, however, measurements associated with randomly oriented grinding cracks were 6 to 30 higher. Crack extension in ring loaded disks occurred on the 111 planes due to both the lower fracture energy and the higher stresses on stiff 111 planes. Germanium exhibits a Weibull scale effect, but does not exhibit significant slow crack growth in distilled water. (n 100), implying that design for quasi static loading can be performed with scaled strength statistics. Practical values for engineering design are a fracture toughness of 0.69 0.02 MPam (megapascals per square root meter) and a Weibull modulus of m 6 2. For well ground and reasonable handled coupons, average fracture strength should be greater than 40 megapascals. Aggregate, polycrystalline elastic constants are Epoly 131 gigapascals, vpoly 0.22.

  15. Deformation parameters influencing prepreg tack

    SciTech Connect

    Ahn, K.J.; Seferis, J.C. ); Pelton, T.; Wilhelm, M. )

    1992-01-01

    A compression to tension apparatus and a methodology capable of measuring prepreg tack have been analyzed in detail in order to establish fundamental material and operating characteristics. Both intrinsic and extrinsic parameters influencing prepreg tack were identified and analyzed using commercially available carbon fiber/epoxy prepregs and mechanical testing equipment. Two different factors, (1) contact (or wetting) area of adjacent prepreg plies and (2) viscoelastic properties of the prepreg, were found to control prepreg tack. At low temperatures, contact area was the main deformation controlling step, while at high temperatures, the viscoelastic property of the prepreg was found to be dominant. Both interlaminar and intralaminar deformations were observed depending on the prepreg systems examined as well as the operating conditions of the test. In addition, hold time, hold pressure, loading rate, resin content, and out-time were also found to affect prepreg tack. Energy of separation, which may be viewed as a descriptor of prepreg tack, was observed to increase with increasing hold time, hold pressure, and loading rate. Energy of separation also showed a maximum value at a specific resin content for a specific prepreg system, while it decreased with increasing prepreg out-time due to prepreg surface characteristic change rather than bulk physical aging. Conclusively, it was observed that prepreg tack must be viewed as an extrinsic, bulk, but surface-sensitive, viscoelastic property which depends on material as well as operating conditions.

  16. MEASUREMENT OF WASTE LOADING IN SALTSTONE

    SciTech Connect

    Harbour, J; Vickie Williams, V

    2008-07-18

    One of the goals of the Saltstone variability study is to identify the operational and compositional variables that control or influence the important processing and performance properties of Saltstone grout mixtures. One of those properties of importance is the Waste Loading (WL) of the decontaminated salt solution (DSS) in the Saltstone waste form. Waste loading is a measure of the amount of waste that can be incorporated within a waste form. The value of the Saltstone waste loading ultimately determines the number of vaults that will be required to disposition all of the DSS. In this report, the waste loading is defined as the volume in milliliters of DSS per liter of Saltstone waste form. The two most important parameters that determine waste loading for Saltstone are water to cementitious material (w/cm) ratio and the cured grout density. Data are provided that show the dependence of waste loading on the w/cm ratio for a fixed DSS composition using the current premix material (45% Blast Furnace Slag (BFS), 45% Fly Ash (FA) and 10% Ordinary Portland Cement (OPC)). The impact of cured grout density on waste loading was also demonstrated. Mixes (at 0.60 w/cm) made with a Modular Caustic side extraction Unit (MCU) simulant and either OPC or BFS have higher cured grout densities than mixes made with premix and increase the WL to 709 mL/L for the OPC mix and 689 mL/L for the BFS mix versus the value of 653 mL/L for MCU in premix at 0.60 w/cm ratio. Bleed liquid reduces the waste loading and lowers the effective w/cm ratio of Saltstone. A method is presented (and will be used in future tasks) for correcting the waste loading and the w/cm ratio of the as-batched mixes in those cases where bleed liquid is present. For example, the Deliquification, Dissolution and Adjustment (DDA) mix at an as-batched 0.60 w/cm ratio, when corrected for % bleed, gives a mix with a 0.55 w/cm ratio and a WL that has been reduced from 662 to 625 mL/L. An example is provided that

  17. Size, Loading Efficiency, and Cytotoxicity of Albumin-Loaded Chitosan Nanoparticles: An Artificial Neural Networks Study.

    PubMed

    Baharifar, Hadi; Amani, Amir

    2017-01-01

    When designing nanoparticles for drug delivery, many variables such as size, loading efficiency, and cytotoxicity should be considered. Usually, smaller particles are preferred in drug delivery because of longer blood circulation time and their ability to escape from immune system, whereas smaller nanoparticles often show increased toxicity. Determination of parameters which affect size of particles and factors such as loading efficiency and cytotoxicity could be very helpful in designing drug delivery systems. In this work, albumin (as a protein drug model)-loaded chitosan nanoparticles were prepared by polyelectrolyte complexation method. Simultaneously, effects of 4 independent variables including chitosan and albumin concentrations, pH, and reaction time were determined on 3 dependent variables (i.e., size, loading efficiency, and cytotoxicity) by artificial neural networks. Results showed that concentrations of initial materials are the most important factors which may affect the dependent variables. A drop in the concentrations decreases the size directly, but they simultaneously decrease loading efficiency and increase cytotoxicity. Therefore, an optimization of the independent variables is required to obtain the most useful preparation.

  18. Coordination of Economic Load Dispatch and Load Frequency Control for Interconnected Power System

    NASA Astrophysics Data System (ADS)

    Shankar, R.; Chatterjee, K.; Chatterjee, T. K.

    2015-03-01

    This paper deals with the coordination of economic load dispatch and load frequency control concepts of the interconnected power system. The total change in the particular control area is shared by each unit according to their participation factor obtained from the calculation of the economic load dispatch. In this work, two control areas are considered, the first control area contains the combination of hydro, thermal and gas generating unit and in the second control area, it contains the combination of the thermal and hydro generating units. Integral controller is used for secondary controller for load frequency control mechanism. A digital simulation is used in conjunction with the genetic algorithm (GA) technique to determine the optimum parameters of the individual gain of integral controller. Three different types of performance indices are considered to measure the appropriateness of the proposed controller. The optimum values of the gains improve the dynamic performance of the controller and reduce the overshoot and maximum frequency deviation and net tie-line power flow deviation error for a particular load change. To show the effectiveness of the proposed controller, simulation result is shown in result and discussion section.

  19. Estimation of dynamic rotor loads for the rotor systems research aircraft: Methodology development and validation

    NASA Technical Reports Server (NTRS)

    Duval, R. W.; Bahrami, M.

    1985-01-01

    The Rotor Systems Research Aircraft uses load cells to isolate the rotor/transmission systm from the fuselage. A mathematical model relating applied rotor loads and inertial loads of the rotor/transmission system to the load cell response is required to allow the load cells to be used to estimate rotor loads from flight data. Such a model is derived analytically by applying a force and moment balance to the isolated rotor/transmission system. The model is tested by comparing its estimated values of applied rotor loads with measured values obtained from a ground based shake test. Discrepancies in the comparison are used to isolate sources of unmodeled external loads. Once the structure of the mathematical model has been validated by comparison with experimental data, the parameters must be identified. Since the parameters may vary with flight condition it is desirable to identify the parameters directly from the flight data. A Maximum Likelihood identification algorithm is derived for this purpose and tested using a computer simulation of load cell data. The identification is found to converge within 10 samples. The rapid convergence facilitates tracking of time varying parameters of the load cell model in flight.

  20. Cyclic-loading Induced Lattice-Strain Asymmetry in Loading and Transverse Directions

    SciTech Connect

    Huang, E-Wen; Barabash, Rozaliya; Clausen, Bjorn; Liaw, Peter K

    2012-01-01

    Cyclic-loading effects on a nickel-based superalloy are investigated with in-situ neutron-diffraction measurements. The thermoelastic-temperature evolution subjected to cyclic loading is estimated based on the lattice-strain evolution. The atomic thermoelastic responses are compared with the measured bulk temperature evolution. Two transitions in the temperature-evolution are observed. The first transition, observed with the neutron-measurement results, is associated with the cyclic hardening/softening-structural transformation. The second transition is observed at larger number of fatigue cycles. It has a distinct origin and is related to the start of irreversible structural transformations during fatigue. A lattice-strain asymmetry behavior is observed. The lattice-strain asymmetry is quantified as a grain-orientation-dependent transverse/loading parameter (P-ratio). The P-ratio parameter evolution reveals the irreversible plastic deformation subjected to the fatigue. The irreversible fatigue phenomena might relate to the formation of the microcracks. At elevated temperatures the cyclic hardening/softening transition starts at lower fatigue cycles as compared to room temperature. A comparison between the room-temperature and the elevated-temperature fatigue experiments is performed. The P-ratio parameters show the same irreversible trends at both the room and the elevated temperatures.

  1. Cooling loads in laboratories

    SciTech Connect

    Wilkins, C.K.; Cook, M.R.

    1999-07-01

    The heating, ventilating, and air-conditioning (HVAC) system for a laboratory must be designed with consideration for safety, air cleanliness, and space temperature. The primary safety concern is to ensure proper coordination between fume hood exhaust and makeup air supply. Air cleanliness is maintained by properly filtering supply air, by delivering adequate room air changes, and by ensuring proper pressure relationships between the laboratory and adjacent spaces. Space temperature is maintained by supplying enough cooling air to offset the amount of heat generated in the room. Each of these factors must be considered, and the one that results in the largest ventilation rate is used to establish the supply and exhaust airflows. The project described in this paper illustrates a case where cooling load is the determining factor in the sizing of the air systems.

  2. Offshore tanker loading system

    SciTech Connect

    Baan, J. de; Heijst, W.J. van.

    1994-01-04

    The present invention relates to an improved flexible loading system which provides fluid communication between a subsea pipeline and a surface vessel including a hose extending from the subsea pipeline to a first buoyancy tank, a second hose extending from the first buoyancy tank to a central buoyancy tank, a second buoyancy tank, means connecting said second buoyancy tank to the sea floor and to the central buoyancy tank whereby the forces exerted on said central buoyant tank by said second hose and said connecting means are balanced to cause said central buoyancy tank to maintain a preselected position, a riser section extending upwardly from said central buoyancy tank and means on the upper termination for engagement by a vessel on the surface to raise said upper termination onto the vessel to complete the communication for moving fluids between the subsea pipeline and the vessel. In one form the means for connecting between the sea floor to the second buoyancy tank includes an anchor on the sea floor and lines extending from the anchor to the second buoyancy tank and from the second buoyancy tank to the central buoyancy tank. In another form of the invention the means for connecting is a third hose extending from a second subsea pipeline to the second buoyancy tank and a fourth hose extending from the second buoyancy tank to the central buoyancy tank. The central buoyancy tank is preferred to be maintained at a level below the water surface which allows full movement of the vessel while connected to the riser section. A swivel may be positioned in the riser section and a pressure relief system may be included in the loading system to protect it from sudden excess pressures. 17 figs.

  3. Load Diffusion in Composite and Smart Structures

    NASA Technical Reports Server (NTRS)

    Horgan, C. O.

    2003-01-01

    The research carried out here builds on our previous NASA supported research on the general topic of edge effects and load diffusion in composite structures. Further fundamental solid mechanics studies were carried out to provide a basis for assessing the complicated modeling necessary for the multi-functional large scale structures used by NASA. An understanding of the fundamental mechanisms of load diffusion in composite subcomponents is essential in developing primary composite structures. Some specific problems recently considered were those of end effects in smart materials and structures, study of the stress response of pressurized linear piezoelectric cylinders for both static and steady rotating configurations, an analysis of the effect of pre-stressing and pre-polarization on the decay of end effects in piezoelectric solids and investigation of constitutive models for hardening rubber-like materials. Our goal in the study of load diffusion is the development of readily applicable results for the decay lengths in terms of non-dimensional material and geometric parameters. Analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and assessing results from finite element analyses. The decay behavior of stresses and other field quantities provides a significant aid towards this process. The analysis is also amenable to parameter study with a large parameter space and should be useful in structural tailoring studies. Special purpose analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and in assessing results from general purpose finite element analyses. For example, a rational basis is needed in choosing where to use three-dimensional to two-dimensional transition finite elements in analyzing stiffened plates and shells. The decay behavior of stresses and other field quantities furnished by

  4. Power system very short-term load prediction

    SciTech Connect

    Trudnowski, D.J.; Johnson, J.M.; Whitney, P.

    1997-02-01

    A fundamental objective of a power-system operating and control scheme is to maintain a match between the system`s overall real-power load and generation. To accurately maintain this match, modern energy management systems require estimates of the future total system load. Several strategies and tools are available for estimating system load. Nearly all of these estimate the future load in 1-hour steps over several hours (or time frames very close to this). While hourly load estimates are very useful for many operation and control decisions, more accurate estimates at closer intervals would also be valuable. This is especially true for emerging Area Generation Control (AGC) strategies such as look-ahead AGC. For these short-term estimation applications, future load estimates out to several minutes at intervals of 1 to 5 minutes are required. The currently emerging operation and control strategies being developed by the BPA are dependent on accurate very short-term load estimates. To meet this need, the BPA commissioned the Pacific Northwest National Laboratory (PNNL) and Montana Tech (an affiliate of the University of Montana) to develop an accurate load prediction algorithm and computer codes that automatically update and can reliably perform in a closed-loop controller for the BPA system. The requirements include accurate load estimation in 5-minute steps out to 2 hours. This report presents the results of this effort and includes: a methodology and algorithms for short-term load prediction that incorporates information from a general hourly forecaster; specific algorithm parameters for implementing the predictor in the BPA system; performance and sensitivity studies of the algorithms on BPA-supplied data; an algorithm for filtering power system load samples as a precursor to inputting into the predictor; and FORTRAN 77 subroutines for implementing the algorithms.

  5. Effects of loading methods on rabbit welfare and meat quality.

    PubMed

    Mazzone, G; Vignola, G; Giammarco, M; Manetta, A C; Lambertini, L

    2010-05-01

    The effects of different loading methods on the welfare, carcass characteristics and meat quality traits of hybrid commercial rabbits were investigated. 384 male rabbits, 82 days old, were transported from the farm to the slaughterhouse. At the farm, 192 rabbits were loaded onto the truck smoothly (S) and 192 rabbits were loaded roughly (R). The S loading method consisted of carefully placing each rabbit into the transport crates. In the R method, the loading was hurriedly and carelessly executed by the transport operator, throwing each animal into the crates fixed on the truck. Live weight before and after transport as well as slaughter data were recorded for each rabbit, and a subset of 80 carcasses were evaluated for meat quality. Blood samples from 80 rabbits were analysed for haematological and biochemical parameters. A significant neutrophilia (P<0.001), lymphocytopaenia (P<0.001) and an increase in serum aspartate aminotransferase (AST) (P<0.01), alanine aminotransferase (ALT) (P<0.001) and creatine kinase (CK) activities (P<0.001) were recorded in all rabbits after transport, independent of the loading method. A twofold increase in serum corticosterone concentration (6.23 vs. 14.88 ng/mL; P=0.001) was observed in all rabbits following transport. Results suggest that the stress parameters analysed were more influenced by transport and handling itself rather than by the different loading methods. The results showed that there was no adverse effect of loading method on carcass traits. Furthermore, the stress condition evidenced by haematological and biochemical parameters prior to slaughter did not affect meat quality.

  6. Variable response load limiting device

    NASA Technical Reports Server (NTRS)

    Mcsmith, Dwight D. (Inventor)

    1988-01-01

    An energy absorbing device used as a load limiting member in a structure to control its response to applied loads is described. It functions by utilizing a spool assembly having flanged ends and an interior cavity of sufficiently large diameter to cause it to deform plastically at a prescribed load. In application, the spool is utilized as a pivot point for the legs of an airplane seat. When properly designed and integrated into the seat arrangement the spool will twist about its axis, deforming plastically when the impact load exceeds the spool yield value. Through this deformation, the spool absorbs the kinetic energy of the movement of the seat at a substantially constant rate, thereby controlling the level of loads transmitted to the seat occupant. By proper sizing and collection of materials, it is possible to control load response in a predictable manner.

  7. Visualization of parameter space for image analysis.

    PubMed

    Pretorius, A Johannes; Bray, Mark-Anthony P; Carpenter, Anne E; Ruddle, Roy A

    2011-12-01

    Image analysis algorithms are often highly parameterized and much human input is needed to optimize parameter settings. This incurs a time cost of up to several days. We analyze and characterize the conventional parameter optimization process for image analysis and formulate user requirements. With this as input, we propose a change in paradigm by optimizing parameters based on parameter sampling and interactive visual exploration. To save time and reduce memory load, users are only involved in the first step--initialization of sampling--and the last step--visual analysis of output. This helps users to more thoroughly explore the parameter space and produce higher quality results. We describe a custom sampling plug-in we developed for CellProfiler--a popular biomedical image analysis framework. Our main focus is the development of an interactive visualization technique that enables users to analyze the relationships between sampled input parameters and corresponding output. We implemented this in a prototype called Paramorama. It provides users with a visual overview of parameters and their sampled values. User-defined areas of interest are presented in a structured way that includes image-based output and a novel layout algorithm. To find optimal parameter settings, users can tag high- and low-quality results to refine their search. We include two case studies to illustrate the utility of this approach.

  8. Dynamic load balancing of applications

    DOEpatents

    Wheat, S.R.

    1997-05-13

    An application-level method for dynamically maintaining global load balance on a parallel computer, particularly on massively parallel MIMD computers is disclosed. Global load balancing is achieved by overlapping neighborhoods of processors, where each neighborhood performs local load balancing. The method supports a large class of finite element and finite difference based applications and provides an automatic element management system to which applications are easily integrated. 13 figs.

  9. Dynamic load balancing of applications

    DOEpatents

    Wheat, Stephen R.

    1997-01-01

    An application-level method for dynamically maintaining global load balance on a parallel computer, particularly on massively parallel MIMD computers. Global load balancing is achieved by overlapping neighborhoods of processors, where each neighborhood performs local load balancing. The method supports a large class of finite element and finite difference based applications and provides an automatic element management system to which applications are easily integrated.

  10. Structural dynamics payload loads estimates

    NASA Technical Reports Server (NTRS)

    Engels, R. C.

    1982-01-01

    Methods for the prediction of loads on large space structures are discussed. Existing approaches to the problem of loads calculation are surveyed. A full scale version of an alternate numerical integration technique to solve the response part of a load cycle is presented, and a set of short cut versions of the algorithm developed. The implementation of these techniques using the software package developed is discussed.

  11. Effects of Loading Duration and Short Rest Insertion on Cancellous and Cortical Bone Adaptation in the Mouse Tibia

    PubMed Central

    Yang, Haisheng; Embry, Rachel E.; Main, Russell P.

    2017-01-01

    The skeleton’s osteogenic response to mechanical loading can be affected by loading duration and rest insertion during a series of loading events. Prior animal loading studies have shown that the cortical bone response saturates quickly and short rest insertions between load cycles can enhance cortical bone formation. However, it remains unknown how loading duration and short rest insertion affect load-induced osteogenesis in the mouse tibial compressive loading model, and particularly in cancellous bone. To address this issue, we applied cyclic loading (-9 N peak load; 4 Hz) to the tibiae of three groups of 16 week-old female C57BL/6 mice for two weeks, with a different number of continuous load cycles applied daily to each group (36, 216 and 1200). A fourth group was loaded under 216 daily load cycles with a 10 s rest insertion after every fourth cycle. We found that as few as 36 load cycles per day were able to induce osteogenic responses in both cancellous and cortical bone. Furthermore, while cortical bone area and thickness continued to increase through 1200 cycles, the incremental increase in the osteogenic response decreased as load number increased, indicating a reduced benefit of the increasing number of load cycles. In the proximal metaphyseal cancellous bone, trabecular thickness increased with load up to 216 cycles. We also found that insertion of a 10 s rest between load cycles did not improve the osteogenic response of the cortical or cancellous tissues compared to continuous loading in this model given the age and sex of the mice and the loading parameters used here. These results suggest that relatively few load cycles (e.g. 36) are sufficient to induce osteogenic responses in both cortical and cancellous bone in the mouse tibial loading model. Mechanistic studies using the mouse tibial loading model to examine bone formation and skeletal mechanobiology could be accomplished with relatively few load cycles. PMID:28076363

  12. Alaska Village Electric Load Calculator

    SciTech Connect

    Devine, M.; Baring-Gould, E. I.

    2004-10-01

    As part of designing a village electric power system, the present and future electric loads must be defined, including both seasonal and daily usage patterns. However, in many cases, detailed electric load information is not readily available. NREL developed the Alaska Village Electric Load Calculator to help estimate the electricity requirements in a village given basic information about the types of facilities located within the community. The purpose of this report is to explain how the load calculator was developed and to provide instructions on its use so that organizations can then use this model to calculate expected electrical energy usage.

  13. In vitro loading of apoferritin.

    PubMed

    de Silva, D; Miller, D M; Reif, D W; Aust, S D

    1992-03-01

    This study compared the effect of loading apoferritin either with ferrous ammonium sulfate in various buffers or with ceruloplasmin and chelated ferrous iron. It was shown that loading of apoferritin with ferrous ammonium sulfate was dependent on buffer and pH, and was directly related to the rate of iron autoxidation. The ceruloplasmin-dependent loading of apoferritin, however, was unaffected by these factors. Isoelectric focusing and amino acid analysis of the differently loaded ferritins showed that ferrous ammonium sulfate loading of apoferritin resulted in the depletion of the basic amino acids, lysine and histidine, probably as a result of protein oxidation. No significant differences in amino acid composition was noted for ceruloplasmin-loaded ferritin. Furthermore, ferritin loaded with ferrous ammonium sulfate released more iron than either native or ceruloplasmin-loaded ferritin when either paraquat or EDTA was used as an iron mobilizing agent. We suggest that the loading of apoferritin with ferrous ammonium sulfate occurred as a result of iron autoxidation and may result in oxidation of amino acids and loss of integrity of the protein, and that ceruloplasmin may act as a catalyst for the incorporation of iron into apoferritin in a manner more closely related to that occurring in vivo.

  14. High-Power Rf Load

    DOEpatents

    Tantawi, Sami G.; Vlieks, Arnold E.

    1998-09-01

    A compact high-power RF load comprises a series of very low Q resonators, or chokes [16], in a circular waveguide [10]. The sequence of chokes absorb the RF power gradually in a short distance while keeping the bandwidth relatively wide. A polarizer [12] at the input end of the load is provided to convert incoming TE.sub.10 mode signals to circularly polarized TE.sub.11 mode signals. Because the load operates in the circularly polarized mode, the energy is uniformly and efficiently absorbed and the load is more compact than a rectangular load. Using these techniques, a load having a bandwidth of 500 MHz can be produced with an average power dissipation level of 1.5 kW at X-band, and a peak power dissipation of 100 MW. The load can be made from common lossy materials, such as stainless steel, and is less than 15 cm in length. These techniques can also produce loads for use as an alternative to ordinary waveguide loads in small and medium RF accelerators, in radar systems, and in other microwave applications. The design is easily scalable to other RF frequencies and adaptable to the use of other lossy materials.

  15. Estimating Nitrogen Loads, BMPs, and Target Loads Exceedance Risks

    EPA Science Inventory

    The Wabash River (WR) watershed, IN, drains two-thirds of the state’s 92 counties and has primarily agricultural land use. The nutrient and sediment loads of the WR significantly increase loads of the Ohio River ultimately polluting the Gulf of Mexico. The objective of this study...

  16. Crane-Load Contact Sensor

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert; Mata, Carlos; Cox, Robert

    2005-01-01

    An electronic instrument has been developed as a prototype of a portable crane-load contact sensor. Such a sensor could be helpful in an application in which the load rests on a base in a horizontal position determined by vertical alignment pins (see Figure 1). If the crane is not positioned to lift the load precisely vertically, then the load can be expected to swing once it has been lifted clear of the pins. If the load is especially heavy, large, and/or fragile, it could hurt workers and/or damage itself and nearby objects. By indicating whether the load remains in contact with the pins when it has been lifted a fraction of the length of the pins, the crane-load contact sensor helps the crane operator determine whether it is safe to lift the load clear of the pins: If there is contact, then the load is resting against the sides of the pins and, hence, it may not be safe to lift; if contact is occasionally broken, then the load is probably not resting against the pins, so it should be safe to lift. It is assumed that the load and base, or at least the pins and the surfaces of the alignment holes in the load, are electrically conductive, so the instrument can use electrical contact to indicate mechanical contact. However, DC resistance cannot be used as an indicator of contact for the following reasons: The load and the base are both electrically grounded through cables (the load is grounded through the lifting cable of the crane) to prevent discharge of static electricity. In other words, the DC resistance between the load and the pins is always low, as though they were always in direct contact. Therefore, instead of DC resistance, the instrument utilizes the AC electrical impedance between the pins and the load. The signal frequency used in the measurement is high enough (.1 MHz) that the impedance contributed by the cables and the electrical ground network of the building in which the crane and the base are situated is significantly greater than the contact

  17. Influence of load by high power on the optical coupler

    NASA Astrophysics Data System (ADS)

    Bednarek, Lukas; Poboril, Radek; Vanderka, Ales; Hajek, Lukas; Nedoma, Jan; Vasinek, Vladimir

    2016-12-01

    Nowadays, aging of the optical components is a very current topic. Therefore, some investigations are focused on this area, so that the aging of the optical components is accelerated by thermal, high power and gamma load. This paper deals by findings of the influence of the load by laser with high optical power on the transmission parameters of the optical coupler. The investigated coupler has one input and eight outputs (1x8). Load by laser with high optical power is realized using a fiber laser with a cascade configuration EDFA amplifiers. The output power of the amplifier is approximately 250 mW. Duration of the load is moving from 104 hours to 139 hours. After each load, input power and output powers of all branches are measured. Following parameters of the optical coupler are calculated using formulas: the insertion losses of the individual branches, split ratio, total losses, homogeneity of the losses and cross-talk between different branches. All measurements are performed at wavelengths 1310 nm and 1550 nm. Individual optical powers are measured 20 times, due to the exclusion of statistical error of the measurement. After measuring, the coupler is connected to the amplifier for next cycle of the load. The paper contains an evaluation of the results of the coupler before and after four cycles of the burden.

  18. Earth's surface loading study using InSAR

    NASA Astrophysics Data System (ADS)

    Amelung, F.; Zhao, W.; Doin, M. P.

    2014-12-01

    Earth's surface loading/unloading such as glacier retreat, lake water level change, ocean tide, cause measurable (centimeter to millimeter) surface deformation from Synthetic Aperture Radar Interferometry (InSAR). Such seasonal or decadal deformation signals are useful for the estimation of the amount of load and the parameterization of crust and upper mantle - typically under an elastic or a visco-elastic mechanism. Since 2010, we established a study of surface loading using small baseline InSAR time-series analysis. Four sites are included in this study, which are Vatnajokull ice cap, Lake Yamzho Yumco, Petermann glacier, and Barnes ice cap using different satellites such as ERS1/2, Envisat, Radarsat-2, TerraSAR-X. We present results that mainly answer three questions: 1) Is InSAR time-series capable for the detection of millimeter level deformation due to surface loading; 2) When the Earth's rheology is known, how much load change occured; 3) When the surface loading is known, what are the Earth's parameters such as Young's modulus, viscosity. For glacier retreat problem, we introduce a new model for the ice mass loss estimation considering the spatial distribution of ice loss. For lake unloading problem, modeled elastic parameters are useful for the comparison to other 1-D models, e.g. the model based on seismic data.

  19. Taming the inevitable: significant parameters of teeter end impacts

    NASA Astrophysics Data System (ADS)

    Schorbach, V.; Dalhoff, P.; Gust, P.

    2014-06-01

    Two bladed wind turbines are recently discussed more often as the question arises for the most suitable offshore turbine concept. Regarding this turbine concept, a solution for the more challenging dynamics is required. A teetered hub has been a solution for quite an amount of the former two bladed turbines. During normal operation this is an efficient possibility to eliminate the hub bending moment coming from unequal blade loading. But looking at extreme load cases the teeter end impact is a major problem. The teeter end impact is quite often described as the occasion which destroys the load reducing advantage of the teeter mechanism. However, a more detailed analysis of the intensity of the hub out of plane bending moment of the teeter end impact including influencing parameters is not given in literature. For this study, the teetered turbine CART2 from NREL is simulated with the aeroelastic tool Bladed 4.5. Design load cases leading to teeter end impacts have been identified for the CART2. The influence of different parameters of teeter end impacts will be analysed. A distinction of these parameters can be made between turbine parameters and teeter system parameters. Rotor mass and speed are turbine parameters. Pitch-teeter-coupling, the free teeter angle and the damping or stiffness of the restraint system belong to the teeter system parameters. The importance of these parameters will be investigated on three different IEC 61400-1-ed. 2 load cases leading to teeter end impacts. The simulation results will be compared with a dimensional analysis of the analytical teeter equations. Results of this study show which parameters have the most significant influence on teeter end impacts. In short, this paper will contribute to a better understanding of teeter end impacts, which are widely regarded as a severe problem but whose nature has not been the subject of a detailed analysis so far.

  20. Parameter Plane Design Method

    DTIC Science & Technology

    1989-03-01

    Th usr a toente aninteer a thca sms b esta 1 Fp-ocsing 2. Enter P1 values, lwgt, ldig - > 9 Table I give us proper values. Table 1. PARAMETER TABLE...necessary and identify by block number) In this thesis a control systems analysis package is developed using parameter plane methods. It is an interactive...designer is able to choose values of the parameters which provide a good compromise between cost and dynamic behavior. 20 Distribution Availability of

  1. HYDROGEN ATOM THERMAL PARAMETERS.

    PubMed

    JENSEN, L H; SUNDARALINGAM, M

    1964-09-11

    Isotropic hydrogen atom thermal parameters for N,N'- hexamethylenebispropionamide have been determined. They show a definite trend and vary from approximately the same as the mean thermal parameters for atoms other than hydrogen near the center of the molecule to appreciably greater for atoms near the end. The indicated trend for this compound, along with other results, provides the basis for a possible explanation of the anomolous values that have been obtained for hydrogen atom thermal parameters.

  2. Perceptual Load Alters Visual Excitability

    ERIC Educational Resources Information Center

    Carmel, David; Thorne, Jeremy D.; Rees, Geraint; Lavie, Nilli

    2011-01-01

    Increasing perceptual load reduces the processing of visual stimuli outside the focus of attention, but the mechanism underlying these effects remains unclear. Here we tested an account attributing the effects of perceptual load to modulations of visual cortex excitability. In contrast to stimulus competition accounts, which propose that load…

  3. Spring loaded locator pin assembly

    DOEpatents

    Groll, Todd A.; White, James P.

    1998-01-01

    This invention deals with spring loaded locator pins. Locator pins are sometimes referred to as captured pins. This is a mechanism which locks two items together with the pin that is spring loaded so that it drops into a locator hole on the work piece.

  4. Robust Multimodal Cognitive Load Measurement

    DTIC Science & Technology

    2014-03-26

    dimension, Hurst exponent ) of electroencephalogram (EEG) signals to evaluate changes in working memory load during the performance of a cognitive task...dimension, Hurst exponent ) of electroencephalogram (EEG) signals to evaluate changes in working memory load during the performance of a cognitive task with...approximate entropies, wavelet-based complexity measures, correlation dimension, Hurst exponent ) of electroencephalogram (EEG) signals to evaluate changes

  5. Cerebrovascular Injury in Blast Loading

    DTIC Science & Technology

    2010-01-01

    TITLE: Cerebrovascular injury in blast loading PRINCIPAL INVESTIGATOR: Kenneth L. Monson, PhD...SUBTITLE Cerebrovascular injury in blast loading 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-08-1-0295 5c. PROGRAM ELEMENT NUMBER 6...and pH control. 15. SUBJECT TERMS Blast brain injury; cerebrovascular injury and dysfunction; shock tube 16. SECURITY CLASSIFICATION OF: 17

  6. Spring loaded locator pin assembly

    DOEpatents

    Groll, T.A.; White, J.P.

    1998-03-03

    This invention deals with spring loaded locator pins. Locator pins are sometimes referred to as captured pins. This is a mechanism which locks two items together with the pin that is spring loaded so that it drops into a locator hole on the work piece. 5 figs.

  7. Angular-compliant hydrodynamic bearing performance under dynamic loads

    NASA Astrophysics Data System (ADS)

    Harnoy, A.; Rachoor, H.

    1993-07-01

    The study is focused on a dynamically loaded composite bearing, consisting of a hydrodynamic journal bearing inside the internal race of a rolling-element bearing. In this combination, the hydrodynamic bearing has an angular-compliant sleeve with a restricted freedom of rotation around its axis. Under static loads, the improvement is primarily in a significant reduction of friction and wear during the starting and stopping. Under periodical loads, our analysis shows that the performance depends on two dimensionless design parameters. Below particular critical values of these parameters, the results show a considerable improvement, demonstrated by a reduction of the maximum eccentricity. However, above the critical values, the bearing becomes unstable. These results indicate the significance of incorporating this computer assisted computation for each design.

  8. Algae inhibition experiment and load characteristics of the algae solution

    NASA Astrophysics Data System (ADS)

    Xiong, L.; Gao, J. X.; Zhang, Y. X.; Yang, Z. K.; Zhang, D. Q.; He, W.

    2016-08-01

    It is necessary to inhibit microbial growth in an industrial cooling water system. This paper has developed a Monopolar/Bipolar polarity high voltage pulser with load adaptability for an algal experimental study. The load characteristics of the Chlorella pyrenoidosa solution were examined, and it was found that the solution load is resistive. The resistance is related to the plate area, concentration, and temperature of the solution. Furthermore, the pulser's treatment actually inhibits the algae cell growth. This article also explores the influence of various parameters of electric pulses on the algal effect. After the experiment, the optimum pulse parameters were determined to be an electric field intensity of 750 V/cm, a pulse width per second of 120μs, and monopolar polarity.

  9. Dynamic analysis of load carriage biomechanics during level walking.

    PubMed

    Ren, Lei; Jones, Richard K; Howard, David

    2005-04-01

    This paper describes an investigation into the biomechanical effects of load carriage dynamics on human locomotion performance. A whole body, inverse dynamics gait model has been developed which uses only kinematic input data to define the gait cycle. To provide input data, three-dimensional gait measurements have been conducted to capture whole body motion while carrying a backpack. A nonlinear suspension model is employed to describe the backpack dynamics. The model parameters for a particular backpack system can be identified using a dynamic load carriage test-rig. Biomechanical assessments have been conducted based on combined gait and pack simulations. It was found that the backpack suspension stiffness and damping have little effect on human locomotion energetics. However, decreasing suspension stiffness offers important biomechanical advantages. The peak values of vertical pack force, acting on the trunk, and lower limb joint loads are all moderated. This would reduce shoulder strap pressures and the risk of injury when heavy loads are carried.

  10. Integrated loading rate determination for wastewater infiltration system sizing

    SciTech Connect

    Jenssen, P.D. . Centre for Soil and Environmental Research); Siegrist, R.L. )

    1991-01-01

    One of the principal parameters used in wastewater system design is the hydraulic loading rate. Historically the determination of the loading rate has been a straight forward process involving selection of a rate based on soil texture or water percolation rate. Research and experience over the past decade has provided additional insight into the complex processes occurring within wastewater-amended soil systems and has suggested the fallacy of this approach. A mean grain size vs. sorting (MESO) diagram constitutes a new basis for soil classification for wastewater infiltration system design. Crude characterization of the soil hydraulic properties is possible according to the MESO Diagram and loading rate as well as certain purification aspects can be assessed from the diagram. In this paper, an approach is described based on the MESO Diagram that integrates soil properties and wastewater pretreatment to yield a loading rate. 53 refs., 3 figs., 2 tabs.

  11. Load support system analysis high speed input pinion configuration

    NASA Technical Reports Server (NTRS)

    Gassel, S. S.; Pirvics, J.

    1979-01-01

    An analysis and a series of computerized calculations were carried out to explore competing prototype design concepts of a shaft and two taper-roller bearings systems to support the high-speed input pinion of an advanced commercial helicopter transmission. The results were used to evaluate designs both for a straddle arrangement where the pinion gear is located between the bearings and for a cantilever arrangement where the pinion is outboard of the two bearings. Effects of varying parameters including applied gear load, preload, wall thickness, interference fits, bearing spacing and pinion gear location on system rigidity, load distribution and bearing rating life were assessed. A comparison of the bearing load distributions for these designs demonstrated that the straddle more equally distributes both radial and axial loads. The performance of these designs over a range of shaft rotational speeds, with lubrication and friction effects included, is also discussed.

  12. Issues related to SPR joints subjected to fatigue loads

    NASA Astrophysics Data System (ADS)

    De Luca, A.; Senatore, F.; Greco, A.

    2016-05-01

    SPR joints will represent an alternative solution to spot welding in automotive field. However, their fatigue behavior shows several critical issues. After a brief introduction of this new solution, different crack modes are described, emphasizing the parameters that characterize them, i.e. the applied loads, the geometry of the joint and other phenomenon as fretting, vibration and corrosion.

  13. A Load Shortening Curve Library for Longitudinally Stiffened Panels

    DTIC Science & Technology

    2010-08-01

    curves. These are compared with similar curves calculated using nonlinear FEA and using design formulas published by the International Association...of parameters values used in load-shortening curve libraries ........................... 7 Table 3: Nonlinear solution strategy...direct assessment with nonlinear finite element analysis (FEA) first reported by Chen et al. [9]. A recent study comparing the ultimate strengths of

  14. Umbilical cable recovery load analysis

    NASA Astrophysics Data System (ADS)

    Yan, Shu-wang; Jia, Zhao-lin; Feng, Xiao-wei; Li, Shi-tao

    2013-06-01

    Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field. The severe ocean environment makes great challenges to umbilical maintenance and repair work. Damaged umbilical is usually recovered for the regular operation of the offshore production system. Analysis on cables in essence is a two-point boundary problem. The tension load at the mudline must be known first, and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation. The recovery analysis also involves umbilical-soil interaction and becomes more complicated. Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed. The analysis results provide a theoretical reference for offshore on-deck operation.

  15. In vivo axial loading of the mouse tibia.

    PubMed

    Melville, Katherine M; Robling, Alexander G; van der Meulen, Marjolein C H

    2015-01-01

    Noninvasive methods to apply controlled, cyclic loads to the living skeleton are used as anabolic procedures to stimulate new bone formation in adults and enhance bone mass accrual in growing animals. These methods are also invaluable for understanding bone signaling pathways. Our focus here is on a particular loading model: in vivo axial compression of the mouse tibia. An advantage of loading the tibia is that changes are present in both the cancellous envelope of the proximal tibia and the cortical bone of the tibial diaphysis. To load the tibia of the mouse axially in vivo, a cyclic compressive load is applied up to five times a week to a single tibia per mouse for a duration lasting from 1 day to 6 weeks. With the contralateral limb as an internal control, the anabolic response of the skeleton to mechanical stimuli can be studied in a pairwise experimental design. Here, we describe the key parameters that must be considered before beginning an in vivo mouse tibial loading experiment, including methods for in vivo strain gauging of the tibial midshaft, and then we describe general methods for loading the mouse tibia for an experiment lasting multiple days.

  16. Buckling behavior of long anisotropic plates subjected to combined loads

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    1995-01-01

    A parametric study is presented of the buckling behavior of infinitely long symmetrically laminated anisotropic plates subjected to combined loads. The study focuses on the interaction of a subcritical (stable) secondary loading state of constant magnitude and a primary destabilizing load that is increased in magnitude until buckling occurs. The loads, considered in this report are uniform axial compression, pure in-plane bending, transverse tension and compression, and shear. Results are presented that were obtained by using a special purpose nondimensional analysis that is well suited for parametric studies of clamped and simply supported plates. In particular, results are presented for a +/- 45(sub S) graphite-epoxy laminate that is highly anisotropic and representative of a laminate used for spacecraft applications. In addition, generic buckling-design charts are presented for a wide range of nondimensional parameters that are applicable to a broad class of laminate constructions. These results show the general behavioral trends of specially orthotropic plates and the effects of flexural anisotropy on plates subjected to various combined loading conditions. An important finding of the present study is that the effects of flexural anisotropy on the buckling resistance of a plate can be significantly more important for plates subjected to combined loads than for plates subjected to single-component loads.

  17. Rock Directed Breaking Under the Impulse Load

    NASA Astrophysics Data System (ADS)

    Khomeriki, Sergo; Mataradze, Edgar; Chikhradze, Nikoloz; Losaberidze, Marine; Khomeriki, Davit; Shatberashvili, Grigol

    2016-10-01

    In the work the problem of directed chipping of facing stone material by means of managing of explosion process is considered. The technology of the mining of decorative stone by the use of explosion energy means the very rapid transfer of potential energy of elastic deformations to kinetic energy. As a result, the explosion impulse, in the expanse of the inertia of rock massive, does not cause the increase of existing cracks. In the course of explosion, the shock wave is propagated by ultrasonic velocity and in this case the medium parameters (pressure, density, temperature, velocity) increase in spurts. In spite of this fact the all three conservation laws of mechanics remain valid on basis of three laws the equations are derived by which the parameters of shock wave may be defined by means of the rock physical-mechanical properties. The load on the body volume at breaking under explosion acts over very small period of the time. Therefore, stressed-deformed state of the rock was studied when the impulse load acts on the boundary. It was considered that the mining of the blocks of facing stone is performed from the hard rocks. This means that the breaking proceeds in the zone of elastic deformation. In the conditions of mentioned assumptions, the expression of the stress tensor and displacement of vector components initiated by stressed-deformed state in the rock are written.

  18. Relations between demographic parameters.

    PubMed

    Demetrius, L

    1979-05-01

    The mean life-expectancy e describes the average prospective life-time of an individual aged zero. This parameter can be explicitly described in terms of the survivorship distribution of the population. The Malthusian parameter r represents the asymptotic growth rate of a population. This parameter can be implicitly expressed in terms of the net-maternity distribution. The parameters e and r incompletely incorporate the age-specific fertility and mortality pattern of a population; distinct populations may have the same growth rate but different net-maternity functions; distinct populations may be characterized by the same mean life expectation but may have different survivorship distributions. This article analyzes a class of parameters called the entropy of a population (Demetrius, 1974a) which distinguishes between net-maternity functions with the same growth rate and also mortality distributions with the same mean life expectation. This class of parameters measures the convexity of the fertility and mortality distributions. This paper analyzes the relations between the entropy parameter and the standard demographic parameters.

  19. Cognitive Load Theory: How Many Types of Load Does It Really Need?

    ERIC Educational Resources Information Center

    Kalyuga, Slava

    2011-01-01

    Cognitive load theory has been traditionally described as involving three separate and additive types of load. Germane load is considered as a learning-relevant load complementing extraneous and intrinsic load. This article argues that, in its traditional treatment, germane load is essentially indistinguishable from intrinsic load, and therefore…

  20. Selection of operating machinery parameters for a bucket excavator

    SciTech Connect

    Fabrichnyi, Y.F.; Baboshin, K.V.; Etinger, I.M.; Mekk, V.A.

    1985-05-01

    The mining industry uses extensively single-bucket excavators of the straight shovel type, like the EKG-4.6, as the most effective way of loading previously loosened hard and abrasive excavated rocks. Therefore, an increase in their working efficiency, mainly as regards increasing productivity, reducing load on the operating machinery, and reducing wear of the operating machinery elements, is of particular importance. Analysis shows that the possibilities for this lie in the correct selection of movement trajectory parameters for the excavator bucket, which for existing excavators are inadequate for loading excavated rock. The authors study here the effect of trajectory parameters on excavator bucket filling, and on their basis they select parameters for the operating machinery.

  1. Changes in biochemical and functional parameters for men during exercise

    PubMed Central

    Karanauskiene, Diana; Zaicenkoviene, Kristina; Stasiule, Loreta

    2015-01-01

    Benefits of physical activity are undeniable. The aim of the present research was to determine the effects of physical activity and age on cholesterol and glucose levels in the blood, as well as changes in the functional parameters of the cardiovascular system, during stepwise increases in physical load for men employed in the same place, but with different levels of physical activity. The subjects were 95 military officers who were divided into groups according to the level of physical activity of their occupation, with veloergometry used as physical load. Cholesterol and glucose levels in the blood were taken as biochemical indices. The results showed that occupational physical activity had a positive effect on biochemical and cardiovascular functional parameters before, during, and after the physical load. Only the cardiovascular rate (systolic blood pressure) in older subjects was significantly higher than that of the younger persons; for all other parameters, age had no effect at all. PMID:28352696

  2. Parametric studies on the load-deflection characteristics of hydraulic snubbers

    SciTech Connect

    Subudhi, M.; Curreri, J., Bezler, P.; Hartzman, M.

    1984-01-01

    Hydraulic snubbers are extensively used in the nuclear power industry for supporting high energy piping systems subjected to dynamic loadings. These devices allow the piping system to displace freely under slowly applied loads, but lock up under sudden excitations. This paper presents the governing differential equations describing the hydro-mechanical mechanisms of a typical snubber. A finite difference computer code, SNUBER, was developed to solve these equations. Using the code, the load deflection characteristics of the unit were developed for a range of parameters of interest. The parameters included leakage orifice area, initial piston location, eyebolt clearance and reservoir pressures. The results include the load deflection characteristics for various combinations of the controlling parameters and some chamber pressure time history profiles. It is intended that the nonlinear characteristic of the snubbers be incorporated into a structural dynamic analysis program to allow prediction of the overall response of nuclear piping supported by these devices and subjected to a variety of loadings.

  3. On dynamic loads in parallel shaft transmissions. 1: Modelling and analysis

    NASA Technical Reports Server (NTRS)

    Lin, Edward Hsiang-Hsi; Huston, Ronald L.; Coy, John J.

    1987-01-01

    A model of a simple parallel-shaft, spur-gear transmission is presented. The model is developed to simulate dynamic loads in power transmissions. Factors affecting these loads are identified. Included are shaft stiffness, local compliance due to contact stress, load sharing, and friction. Governing differential equations are developed and a solution procedure is outlined. A parameter study of the solutions is presented in NASA TM-100181 (AVSCOM TM-87-C-3).

  4. Spinning Reserve from Responsive Load

    SciTech Connect

    Kueck, John D; Kirby, Brendan J; Laughner, T; Morris, K

    2009-01-01

    As power system costs rise and capacity is strained demand response can provide a significant system reliability benefit at a potentially attractive cost. The 162 room Music Road Hotel in Pigeon Forge Tennessee agreed to host a spinning reserve test. The Tennessee Valley Authority (TVA) supplied real-time metering and monitoring expertise to record total hotel load during both normal operations and testing. Preliminary testing showed that hotel load can be curtailed by 22% to 37% depending on the outdoor temperature and the time of day. The load drop was very rapid, essentially as fast as the 2 second metering could detect.

  5. Parameter estimating state reconstruction

    NASA Technical Reports Server (NTRS)

    George, E. B.

    1976-01-01

    Parameter estimation is considered for systems whose entire state cannot be measured. Linear observers are designed to recover the unmeasured states to a sufficient accuracy to permit the estimation process. There are three distinct dynamics that must be accommodated in the system design: the dynamics of the plant, the dynamics of the observer, and the system updating of the parameter estimation. The latter two are designed to minimize interaction of the involved systems. These techniques are extended to weakly nonlinear systems. The application to a simulation of a space shuttle POGO system test is of particular interest. A nonlinear simulation of the system is developed, observers designed, and the parameters estimated.

  6. 14 CFR 23.421 - Balancing loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Balancing loads. 23.421 Section 23.421... Balancing Surfaces § 23.421 Balancing loads. (a) A horizontal surface balancing load is a load necessary to... balancing surfaces must be designed for the balancing loads occurring at any point on the limit...

  7. 14 CFR 23.421 - Balancing loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Balancing loads. 23.421 Section 23.421... Balancing Surfaces § 23.421 Balancing loads. (a) A horizontal surface balancing load is a load necessary to... balancing surfaces must be designed for the balancing loads occurring at any point on the limit...

  8. 14 CFR 23.421 - Balancing loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Balancing loads. 23.421 Section 23.421... Balancing Surfaces § 23.421 Balancing loads. (a) A horizontal surface balancing load is a load necessary to... balancing surfaces must be designed for the balancing loads occurring at any point on the limit...

  9. 14 CFR 23.421 - Balancing loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Balancing loads. 23.421 Section 23.421... Balancing Surfaces § 23.421 Balancing loads. (a) A horizontal surface balancing load is a load necessary to... balancing surfaces must be designed for the balancing loads occurring at any point on the limit...

  10. 14 CFR 23.421 - Balancing loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Balancing loads. 23.421 Section 23.421... Balancing Surfaces § 23.421 Balancing loads. (a) A horizontal surface balancing load is a load necessary to... balancing surfaces must be designed for the balancing loads occurring at any point on the limit...

  11. The brain hypocretins and their receptors: mediators of allostatic arousal.

    PubMed

    Carter, Matthew E; Schaich Borg, Jana; de Lecea, Luis

    2009-02-01

    The hypocretins (abbreviated 'Hcrts' - also called 'orexins') are two neuropeptides secreted exclusively by a small population of neurons in the lateral hypothalamus. These peptides bind to two receptors located throughout the brain in nuclei associated with diverse cognitive and physiological functions. Initially, the brain Hcrt system was found to have a major role in the regulation of sleep/wake transitions. More recent studies indicate Hcrts may play a role in other physiological functions, including food intake, addiction, and stress. Taken together, these studies suggest a general role for Hcrts in mediating arousal, especially when an organism must respond to unexpected stressors and challenges in the environment.

  12. Bone QUS measurement performed under loading condition, a more accuracy ultrasound method for osteoporosis diagnosis.

    PubMed

    Liu, Chengrui; Niu, Haijun; Fan, Yubo; Li, Deyu

    2012-10-01

    Osteoporosis is a worldwide health problem with enormous social and economic impact. Quantitative ultrasound (QUS) method provides comprehensive information on bone mass, microstructure and mechanical properties of the bone. And the cheap, safe and portable ultrasound equipment is more suitable for public health monitoring. QUS measurement was normally performed on bone specimens without mechanical loading. But human bones are subjected to loading during routine daily activities, and physical loading leads to the changes of bone microstructure and mechanical properties. We hypothesized that bone QUS parameters measured under loading condition differ from those measured without loading because the microstructure of bone was changed when loading subjected to bone. Furthermore, when loading was subjected on bone, the loading-lead microstructure change of osteoporosis bone may larger than that of health bone. By considering the high relationship between bone microstructure and QUS parameters, the QUS parameters of osteoporosis bone may changed larger than that of health bone. So osteoporosis may be detected more effectively by the combination of QUS method and mechanical loading.

  13. Estimation of Forest Fuel Load from Radar Remote Sensing

    NASA Technical Reports Server (NTRS)

    Saatchi, Sassan; Despain, Don G.; Halligan, Kerry; Crabtree, Robert

    2007-01-01

    Understanding fire behavior characteristics and planning for fire management require maps showing the distribution of wildfire fuel loads at medium to fine spatial resolution across large landscapes. Radar sensors from airborne or spaceborne platforms have the potential of providing quantitative information about the forest structure and biomass components that can be readily translated to meaningful fuel load estimates for fire management. In this paper, we used multifrequency polarimetric synthetic aperture radar imagery acquired over a large area of the Yellowstone National Park (YNP) by the AIRSAR sensor, to estimate the distribution of forest biomass and canopy fuel loads. Semi-empirical algorithms were developed to estimate crown and stem biomass and three major fuel load parameters, canopy fuel weight, canopy bulk density, and foliage moisture content. These estimates when compared directly to measurements made at plot and stand levels, provided more than 70% accuracy, and when partitioned into fuel load classes, provided more than 85% accuracy. Specifically, the radar generated fuel parameters were in good agreement with the field-based fuel measurements, resulting in coefficients of determination of R(sup 2) = 85 for the canopy fuel weight, R(sup 2)=.84 for canopy bulk density and R(sup 2) = 0.78 for the foliage biomass.

  14. Estimation of forest fuel load from radar remote sensing

    USGS Publications Warehouse

    Saatchi, S.; Halligan, K.; Despain, D.G.; Crabtree, R.L.

    2007-01-01

    Understanding fire behavior characteristics and planning for fire management require maps showing the distribution of wildfire fuel loads at medium to fine spatial resolution across large landscapes. Radar sensors from airborne or spaceborne platforms have the potential of providing quantitative information about the forest structure and biomass components that can be readily translated to meaningful fuel load estimates for fire management. In this paper, we used multifrequency polarimetric synthetic aperture radar (SAR) imagery acquired over a large area of the Yellowstone National Park by the Airborne SAR sensor to estimate the distribution of forest biomass and canopy fuel loads. Semiempirical algorithms were developed to estimate crown and stem biomass and three major fuel load parameters, namely: 1) canopy fuel weight; 2) canopy bulk density; and 3) foliage moisture content. These estimates, when compared directly to measurements made at plot and stand levels, provided more than 70% accuracy and, when partitioned into fuel load classes, provided more than 85% accuracy. Specifically, the radar-generated fuel parameters were in good agreement with the field-based fuel measurements, resulting in coefficients of determination of R2 = 85 for the canopy fuel weight, R 2 = 0.84 for canopy bulk density, and R2 =0.78 for the foliage biomass. ?? 2007 IEEE.

  15. Maximizing TDRS Command Load Lifetime

    NASA Technical Reports Server (NTRS)

    Brown, Aaron J.

    2002-01-01

    The GNC software onboard ISS utilizes TORS command loads, and a simplistic model of TORS orbital motion to generate onboard TORS state vectors. Each TORS command load contains five "invariant" orbital elements which serve as inputs to the onboard propagation algorithm. These elements include semi-major axis, inclination, time of last ascending node crossing, right ascension of ascending node, and mean motion. Running parallel to the onboard software is the TORS Command Builder Tool application, located in the JSC Mission Control Center. The TORS Command Builder Tool is responsible for building the TORS command loads using a ground TORS state vector, mirroring the onboard propagation algorithm, and assessing the fidelity of current TORS command loads onboard ISS. The tool works by extracting a ground state vector at a given time from a current TORS ephemeris, and then calculating the corresponding "onboard" TORS state vector at the same time using the current onboard TORS command load. The tool then performs a comparison between these two vectors and displays the relative differences in the command builder tool GUI. If the RSS position difference between these two vectors exceeds the tolerable lim its, a new command load is built using the ground state vector and uplinked to ISS. A command load's lifetime is therefore defined as the time from when a command load is built to the time the RSS position difference exceeds the tolerable limit. From the outset of TORS command load operations (STS-98), command load lifetime was limited to approximately one week due to the simplicity of both the onboard propagation algorithm, and the algorithm used by the command builder tool to generate the invariant orbital elements. It was soon desired to extend command load lifetime in order to minimize potential risk due to frequent ISS commanding. Initial studies indicated that command load lifetime was most sensitive to changes in mean motion. Finding a suitable value for mean motion

  16. Loading and conjugating cavity biostructures

    DOEpatents

    Hainfeld, J.F.

    1995-08-22

    Methods for the preparation and use of a biological delivery system are disclosed. The method of preparation includes the loading of a non-biological material into a biostructure having a load-bearing structure. The method also includes the removal of some of the biostructure`s contents and the loading of a non-biological material into the biostructure. The biostructure is biologically compatible with the host, and preferably is derived from the host, the host`s species or a related species. The loaded biostructure is used directly, or it can be targeted to specific cells, tissues and/or organs within a host. The targeted biostructure can be used to deliver the non-biological material to a specified tissue, organ or cell within a host for diagnostic, therapeutic or other purposes. 11 figs.

  17. Plutonium Immobilization Can Loading Concepts

    SciTech Connect

    Kriikku, E.; Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.; Rogers, L.; Fiscus, J.; Dyches, G.

    1998-05-01

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses five can loading conceptual designs and the lists the advantages and disadvantages for each concept. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas. The can loading welder and cutter are very similar to the existing Savannah River Site (SRS) FB-Line bagless transfer welder and cutter and thus they are a low priority development item.

  18. Sandia Wind Turbine Loads Database

    DOE Data Explorer

    The Sandia Wind Turbine Loads Database is divided into six files, each corresponding to approximately 16 years of simulation. The files are text files with data in columnar format. The 424MB zipped file containing six data files can be downloaded by the public. The files simulate 10-minute maximum loads for the NREL 5MW wind turbine. The details of the loads simulations can be found in the paper: “Decades of Wind Turbine Loads Simulations”, M. Barone, J. Paquette, B. Resor, and L. Manuel, AIAA2012-1288 (3.69MB PDF). Note that the site-average wind speed is 10 m/s (class I-B), not the 8.5 m/s reported in the paper.

  19. Structural load control during construction

    NASA Astrophysics Data System (ADS)

    Mikulas, Martin

    The topics are presented in viewgraph form and include the following: examples of high transient loadings on large space structures; energy absorbing/load limiting strut research objectives; scope of research on energy absorbing struts to date; energy characteristics of cantilevered trusses with a tip load; ten bay long resilient truss example; stored energy characteristics of one meter deep truss; energy absorbing potential for 10-bay 5-meter deep truss; schematic of energy absorbing strut; linear load and motion control actuator; rigid body response of a solar array to the shuttle thruster pressure impingement; solar array piecewise linear response; solar array characteristics; solar array tip deflection and required actuator stroke; solar array response from finite element analysis; 12 bay energy absorbing test bed dynamics; and new AERO-Lab with 12-bay test beam.

  20. Loading and conjugating cavity biostructures

    DOEpatents

    Hainfeld, James F.

    1997-11-25

    Methods for the preparation and use of a biological delivery system are disclosed. The method of preparation includes the loading of a non-biological material into a biostructure having a load-bearing structure. The method also includes the removal of some of the biostructure's contents and the loading of a non-biological material into the biostructure. The biostructure is biologically compatible with the host, and preferably is derived from the host, the host's species or a related species. The loaded biostructure is used directly, or it can be targeted to specific cells, tissues and/or organs within a host. The targeted biostructure can be used to deliver the non-biological material to a specified tissue, organ or cell within a host for diagnostic, therapeutic or other purposes.

  1. Duty Cycle of Deformational Loading Influences the Growth of Engineered Articular Cartilage.

    PubMed

    Ng, Kenneth W; Mauck, Robert L; Wang, Christopher C-B; Kelly, Terri-Ann N; Ho, Mandy M-Y; Chen, Faye Hui; Ateshian, Gerard A; Hung, Clark T

    2009-09-01

    This study examines how variations in the duty cycle (the duration of applied loading) of deformational loading can influence the mechanical properties of tissue engineered cartilage constructs over one month in bioreactor culture. Dynamic loading was carried out with three different duty cycles: 1 h on/1 h off for a total of 3 h loading/day, 3 h continuous loading, or 6 h of continuous loading per day, with all loading performed 5 days/week. All loaded groups showed significant increases in Young's modulus after one month (vs. free swelling controls), but only loading for a continuous 3 and 6 h showed significant increases in dynamic modulus by this time point. Histological analysis showed that dynamic loading can increase cartilage oligomeric matrix protein (COMP) and collagen types II and IX, as well as prevent the formation of a fibrous capsule around the construct. Type II and IX collagen deposition increased with increased with duration of applied loading. These results point to the efficacy of dynamic deformational loading in the mechanical preconditioning of engineered articular cartilage constructs. Furthermore, these results highlight the ability to dictate mechanical properties with variations in mechanical input parameters, and the possible importance of other cartilage matrix molecules, such as COMP, in establishing the functional material properties of engineered constructs.

  2. Buckling Behavior of Long Symmetrically Laminated Plates Subjected to Shear and Linearly Varying Axial Edge Loads

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    1997-01-01

    A parametric study of the buckling behavior of infinitely long symmetrically laminated anisotropic plates that are subjected to linearly varying edge loads, uniform shear loads, or combinations of these loads is presented. The study focuses on the effects of the shape of linearly varying edge load distribution, plate orthotropy, and plate flexural anisotropy on plate buckling behavior. In addition, the study exmines the interaction of linearly varying edge loads and uniform shear loads with plate flexural anisotropy and orthotropy. Results obtained by using a special purpose nondimensional analysis that is well suited for parametric studies of clamped and simply supported plates are presented for [+/- theta](sub s), thin graphite-epoxy laminates that are representative of spacecraft structural components. Also, numerous generic buckling-design charts are presented for a wide range of nondimensional parameters that are applicable to a broad class of laminate constructions. These charts show explicitly the effects of flexural orthotropy and flexural anisotropy on plate buckling behavior for linearly varying edge loads, uniform shear loads, or combinations of these loads. The most important finding of the present study is that specially orthotropic and flexurally anisotropic plates that are subjected to an axial edge load distribution that is tension dominated can support shear loads that are larger in magnitude than the shear buckling load.

  3. Split torque transmission load sharing

    NASA Technical Reports Server (NTRS)

    Krantz, T. L.; Rashidi, M.; Kish, J. G.

    1992-01-01

    Split torque transmissions are attractive alternatives to conventional planetary designs for helicopter transmissions. The split torque designs can offer lighter weight and fewer parts but have not been used extensively for lack of experience, especially with obtaining proper load sharing. Two split torque designs that use different load sharing methods have been studied. Precise indexing and alignment of the geartrain to produce acceptable load sharing has been demonstrated. An elastomeric torque splitter that has large torsional compliance and damping produces even better load sharing while reducing dynamic transmission error and noise. However, the elastomeric torque splitter as now configured is not capable over the full range of operating conditions of a fielded system. A thrust balancing load sharing device was evaluated. Friction forces that oppose the motion of the balance mechanism are significant. A static analysis suggests increasing the helix angle of the input pinion of the thrust balancing design. Also, dynamic analysis of this design predicts good load sharing and significant torsional response to accumulative pitch errors of the gears.

  4. Drug Loading of Mesoporous Silicon

    NASA Astrophysics Data System (ADS)

    Moffitt, Anne; Coffer, Jeff; Wang, Mengjia

    2011-03-01

    The nanostructuring of crystalline solids with low aqueous solubilities by their incorporation into mesoporous host materials is one route to improve the bioavailability of such solids. Earlier studies suggest that mesoporous Si (PSi), with pore widths in the range of 5-50 nm, is a candidate for such an approach. In this presentation, we describe efforts to load curcumin into free-standing microparticles of PSi. Curcumin is a compound extracted from turmeric root, which is an ingredient of curry. Curucmin has shown activity against selected cancer cell lines, bacteria, and other medical conditions. However, curcumin has a very low bioavailability due to its extremely low water solubility (0.6 μ g/mL). Incorporation of curcumin was achieved by straightforward loading of the molten solid at 185circ; C. Loading experiments were performed using PSi particles of two different size ranges, 45-75 μ m and 150-250 μ m. Longer loading times and ratio of curcumin to PSi leads to a higher percentage of loaded curcumin in both PSi particle sizes (as determined by weight difference). The extent of curcumin crystallinity was assessed by x-ray diffraction (XRD). The solubility and release kinetics of loaded curcumin from the PSi was determined by extraction into water at 37circ; C, with analysis using UV-VIS spectrometry. NSF-REU and TCU.

  5. Structural assessment of accident loads

    SciTech Connect

    Wagenblast, G.R., Westinghouse Hanford

    1996-05-28

    Structural assessments were made for specific accident loads for specific catch, receiver, and storage tanks. The evaluation herein represents level-of-effort order-of-magnitude estimates of limiting loads that would lead to collapse or rupture of the tank and unmitigated loss of confinement for the waste. Structural capacities were established using failure criteria. Compliance with codes such as ACI, ASCE, ASME, RCRA, UBC, WAC, and DOE Orders was `NOT` maintained. Normal code practice is to prevent failure with margins consistent with expected variations in loads and strengths and confidence in analysis techniques. The evaluation herein represent estimates of code limits without code load factors or code strength reduction factors, and loading beyond such a limit is considered as an onset of some failure mode. The exact nature of the failure mode and its relation to a safe condition is a judgment of the analyst. Consequently, these `RESULTS SHALL NOT BE USED TO ESTABLISH OPERATING OR SAFETY LOAD LIMITS FOR THESE TANKS`.

  6. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  7. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  8. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  9. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  10. 14 CFR 23.511 - Ground load; unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... coefficient of friction of 0.8 applied to the main gear and its supporting structure. (b) Unequal tire loads... CATEGORY AIRPLANES Structure Ground Loads § 23.511 Ground load; unsymmetrical loads on multiple-wheel...

  11. Monte Carlo studies of sampling strategies for estimating tributary loads

    SciTech Connect

    Richards, R.P.; Holloway, J.

    1987-10-01

    Monte Carlo techniques were used to evaluate the accuracy and precision of tributary load estimates, as these are affected by sampling frequency and pattern, calculation method, watershed size, and parameter behavior during storm runoff events. Simulated years consisting of 1460 observations were chosen at random with replacement from data sets of more than 4000 samples. Patterned subsampling of these simulated years produced data appropriate to each sampling frequency and pattern, from which load estimates were calculated. Thus, results for all sampling strategies were based on the same series of simulate years. Sampling frequencies ranged from 12 to roughly 600 samples per year. Unstratified and flow-stratified sampling were examined, and loads were calculated with and without the use of the Beale Ratio Estimator. All loads were evaluated by comparison with loads calculated from all 1460 samples in the simulated year. Studies consisting of 1000 iterations were repeated twice for each of five parameters in each of three watersheds. The results show that bias and precision of loading estimates are affected not only by the frequency and pattern of sampling and the calculation approach used, but also by the watershed size and the behavior of the chemical species being monitored. Furthermore, considerable interaction exists between these factors. In every case, loads based on flow-stratified sampling and calculated using the Beale ratio estimator provided the best results among the strategies examined. Differences in bias and precision among watersheds and among transported materials are related to the variability of instantaneous fluxes in the systems being monitored. These differences are qualitatively predictable from knowledge of the time behavior of the material and hydrological systems involved.

  12. Monte Carlo Studies of Sampling Strategies for Estimating Tributary Loads

    NASA Astrophysics Data System (ADS)

    Richards, R. Peter; Holloway, Jim

    1987-10-01

    Monte Carlo techniques were used to evaluate the accuracy and precision of tributary load estimates, as these are affected by sampling frequency and pattern, calculation method, watershed size, and parameter behavior during storm runoff events. Simulated years consisting of 1460 observations were chosen at random with replacement from data sets of more than 4000 samples. Patterned subsampling of these simulated years produced data appropriate to each sampling frequency and pattern, from which load estimates were calculated. Thus results for all sampling strategies were based on the same series of simulated years. Sampling frequencies ranged from 12 to roughly 600 samples per year. Unstratified and flow-stratified sampling were examined, and loads were calculated with and without the use of the Beale Ratio Estimator. All loads were evaluated by comparison with loads calculated from all 1460 samples in the simulated year. Studies consisting of 1000 iterations were repeated twice for each of five parameters in each of three watersheds. The results show that bias and precision of loading estimates are affected not only by the frequency and pattern of sampling and the calculation approach used, but also by the watershed size and the behavior of the chemical species being monitored. Furthermore, considerable interaction exists between these factors. In every case, loads based on flow-stratified sampling and calculated using the Beale ratio estimator provided the best results among the strategies examined. Differences in bias and precision among watersheds and among transported materials are related to the variability of instantaneous fluxes in the systems being monitored. These differences are qualitatively predictable from knowledge of the time behavior of the material and hydrological systems involved. Attempts to derive quantitative relationships to predict the sampling effort required to achieve a specified level of precision have not been successful.

  13. 14 CFR 23.507 - Jacking loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) Vertical-load factor of 1.35 times the static reactions. (2) Fore, aft, and lateral load factors of 0.4 times the vertical static reactions. (b) The horizontal loads at the jack points must be reacted...

  14. 14 CFR 23.507 - Jacking loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Vertical-load factor of 1.35 times the static reactions. (2) Fore, aft, and lateral load factors of 0.4 times the vertical static reactions. (b) The horizontal loads at the jack points must be reacted...

  15. 14 CFR 23.507 - Jacking loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Vertical-load factor of 1.35 times the static reactions. (2) Fore, aft, and lateral load factors of 0.4 times the vertical static reactions. (b) The horizontal loads at the jack points must be reacted...

  16. 14 CFR 23.507 - Jacking loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Vertical-load factor of 1.35 times the static reactions. (2) Fore, aft, and lateral load factors of 0.4 times the vertical static reactions. (b) The horizontal loads at the jack points must be reacted...

  17. 14 CFR 23.507 - Jacking loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) Vertical-load factor of 1.35 times the static reactions. (2) Fore, aft, and lateral load factors of 0.4 times the vertical static reactions. (b) The horizontal loads at the jack points must be reacted...

  18. Drainage basin control of acid loadings to two Adirondack lakes

    NASA Astrophysics Data System (ADS)

    Booty, W. G.; Depinto, J. V.; Scheffe, R. D.

    1988-07-01

    Two adjacent Adirondack Park (New York) calibrated watersheds (Woods Lake and Cranberry Pond), which receive identical atmospheric inputs, generate significantly different unit area of watershed loading rates of acidity to their respective lakes. A watershed acidification model is used to evaluate the watershed parameters which are responsible for the observed differences in acid loadings to the lakes. The greater overall mean depth of overburden on Woods Lake watershed, which supplies a greater buffer capacity as well as a longer retention time of groundwater, appears to be the major factor responsible for the differences.

  19. Effects of state recovery on creep buckling under variable loading

    NASA Technical Reports Server (NTRS)

    Robinson, D. N.; Arnold, S. M.

    1988-01-01

    Structural alloys embody internal mechanisms that allow recovery of state with varying stress and elevated temperature, i.e., they can return to a softer state following periods of hardening. Such material behavior is known to strongly influence structural response under some important thermomechanical loadings, for example, that involving thermal ratchetting. The influence of dynamic and thermal recovery on the creep buckling of a column under variable loading is investigated. The column is taken as the idealized (Shanley) sandwich column. The constitutive model, unlike the commonly employed Norton creep model, incorporates a representation of both dynamic and thermal (state) recovery. The material parameters of the constitutive model are chosen to characterize Narloy Z, a representative copper alloy used in thrust nozzle liners of reusable rocket engines. Variable loading histories include rapid cyclic unloading/reloading sequences and intermittent reductions of load for extended periods of time; these are superimposed on a constant load. The calculated results show that state recovery significantly affects creep buckling under variable loading.

  20. Effects of state recovery on creep buckling under variable loading

    NASA Technical Reports Server (NTRS)

    Robinson, D. N.; Arnold, S. M.

    1990-01-01

    Structural alloys embody internal mechanisms that allow recovery of state with varying stress and elevated temperature, i.e., they can return to a softer state following periods of hardening. Such material behavior is known to strongly influence structural response under some important thermomechanical loadings, for example, that involving thermal ratchetting. The influence of dynamic and thermal recovery on the creep buckling of a column under variable loading is investigated. The column is taken as the idealized (Shanley) sandwich column. The constitutive model, unlike the commonly employed Norton creep model, incorporates a representation of both dynamic and thermal (state) recovery. The material parameters of the constitutive model are chosen to characterize Narloy Z, a representative copper alloy used in thrust nozzle liners of reusable rocket engines. Variable loading histories include rapid cyclic unloading/reloading sequences and intermittent reductions of load for extended periods of time; these are superimposed on a constant load. The calculated results show that state recovery significantly affects creep buckling under variable loading.

  1. Effects of state recovery on creep buckling under variable loading

    NASA Technical Reports Server (NTRS)

    Robinson, D. N.; Arnold, S. M.

    1986-01-01

    Structural alloys embody internal mechanisms that allow recovery of state with varying stress and elevated temperature, i.e., they can return to a softer state following periods of hardening. Such material behavior is known to strongly influence structural response under some important thermomechanical loadings, for example, that involving thermal ratchetting. The influence of dynamic and thermal recovery on the creep buckling of a column under variable loading is investigated. The column is taken as the idealized (Shanley) sandwich column. The constitutive model, unlike the commonly employed Norton creep model, incorporates a representation of both dynamic and thermal (state) recovery. The material parameters of the constitutive model are chosen to characterize Narloy Z, a representative copper alloy used in thrust nozzle liners of reusable rocket engines. Variable loading histories include rapid cyclic unloading/reloading sequences and intermittent reductions of load for extended periods of time; these are superimposed on a constant load. The calculated results show that state recovery significantly affects creep buckling under variable loading. Structural alloys embody internal mechanisms that allow recovery of state with varying stress and time.

  2. Engine System Loads Analysis Compared to Hot-Fire Data

    NASA Technical Reports Server (NTRS)

    Frady, Gregory P.; Jennings, John M.; Mims, Katherine; Brunty, Joseph; Christensen, Eric R.; McConnaughey, Paul R. (Technical Monitor)

    2002-01-01

    Early implementation of structural dynamics finite element analyses for calculation of design loads is considered common design practice for high volume manufacturing industries such as automotive and aeronautical industries. However with the rarity of rocket engine development programs starts, these tools are relatively new to the design of rocket engines. In the NASA MC-1 engine program, the focus was to reduce the cost-to-weight ratio. The techniques for structural dynamics analysis practices, were tailored in this program to meet both production and structural design goals. Perturbation of rocket engine design parameters resulted in a number of MC-1 load cycles necessary to characterize the impact due to mass and stiffness changes. Evolution of loads and load extraction methodologies, parametric considerations and a discussion of load path sensitivities are important during the design and integration of a new engine system. During the final stages of development, it is important to verify the results of an engine system model to determine the validity of the results. During the final stages of the MC-1 program, hot-fire test results were obtained and compared to the structural design loads calculated by the engine system model. These comparisons are presented in this paper.

  3. The effects of load drop, uniform load and concentrated loads on waste tanks

    SciTech Connect

    Marusich, R.M., Westinghouse Hanford

    1996-09-06

    This document provides the supporting calculations performed by others specifically for the TWRS FSAR and more detailed summaries of the important references issued in the past regarding the effects of various loads.

  4. MSSM without free parameters

    NASA Astrophysics Data System (ADS)

    Kitano, Ryuichiro; Motono, Ryuji; Nagai, Minoru

    2016-12-01

    It is often argued that the minimal supersymmetric standard model has O (100 ) free parameters, and the generic parameter region is already excluded by the null observation of the flavor and C P -violating processes as well as the constraints from the LHC experiments. This situation naturally leads us to consider the case where all the dangerous soft supersymmetry breaking terms, such as the scalar masses and scalar couplings, are absent, while only the unified gaugino mass term and the μ term are nonvanishing at the grand unification scale. We revisit this simple situation taking into account the observed Higgs boson mass, 125 GeV. Since the gaugino mass and the μ term are fixed in order to explain the Higgs boson and the Z boson masses, there is no free parameter left in this scenario. We find that there are three independent parameter sets that exist including ones which have not been discussed in the literature. We also find that the abundance of the dark matter can be explained by relic gravitinos which are nonthermally produced as decay products of the supersymmetry particles while satisfying constraints from big bang nucleosynthesis. We discuss the effects of the gravity mediation which generically gives a contribution to the soft terms of the order of the gravitino mass. It turns out that a newly found parameter set is preferable to explain the Higgs boson mass as well as the gravitino dark matter while satisfying the constraints from the electric dipole moments of the electron and the nucleon.

  5. Self-aligning biaxial load frame

    DOEpatents

    Ward, Michael B.; Epstein, Jonathan S.; Lloyd, W. Randolph

    1994-01-01

    An self-aligning biaxial loading apparatus for use in testing the strength of specimens while maintaining a constant specimen centroid during the loading operation. The self-aligning biaxial loading apparatus consists of a load frame and two load assemblies for imparting two independent perpendicular forces upon a test specimen. The constant test specimen centroid is maintained by providing elements for linear motion of the load frame relative to a fixed crosshead, and by alignment and linear motion elements of one load assembly relative to the load frame.

  6. Self-aligning biaxial load frame

    DOEpatents

    Ward, M.B.; Epstein, J.S.; Lloyd, W.R.

    1994-01-18

    An self-aligning biaxial loading apparatus for use in testing the strength of specimens while maintaining a constant specimen centroid during the loading operation. The self-aligning biaxial loading apparatus consists of a load frame and two load assemblies for imparting two independent perpendicular forces upon a test specimen. The constant test specimen centroid is maintained by providing elements for linear motion of the load frame relative to a fixed cross head, and by alignment and linear motion elements of one load assembly relative to the load frame. 3 figures.

  7. 29 CFR 1919.29 - Limitations on safe working loads and proof loads.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Limitations on safe working loads and proof loads. 1919.29... Loads; Heat Treatment; Competent Persons § 1919.29 Limitations on safe working loads and proof loads. The proof loads specified by §§ 1919.27 and 1919.28 shall be adjusted as necessary to meet...

  8. Aircraft parameter estimation

    NASA Technical Reports Server (NTRS)

    Iliff, Kenneth W.

    1987-01-01

    The aircraft parameter estimation problem is used to illustrate the utility of parameter estimation, which applies to many engineering and scientific fields. Maximum likelihood estimation has been used to extract stability and control derivatives from flight data for many years. This paper presents some of the basic concepts of aircraft parameter estimation and briefly surveys the literature in the field. The maximum likelihood estimator is discussed, and the basic concepts of minimization and estimation are examined for a simple simulated aircraft example. The cost functions that are to be minimized during estimation are defined and discussed. Graphic representations of the cost functions are given to illustrate the minimization process. Finally, the basic concepts are generalized, and estimation from flight data is discussed. Some of the major conclusions for the simulated example are also developed for the analysis of flight data from the F-14, highly maneuverable aircraft technology (HiMAT), and space shuttle vehicles.

  9. Target parameter estimation

    NASA Technical Reports Server (NTRS)

    Hocking, W. K.

    1989-01-01

    The objective of any radar experiment is to determine as much as possible about the entities which scatter the radiation. This review discusses many of the various parameters which can be deduced in a radar experiment, and also critically examines the procedures used to deduce them. Methods for determining the mean wind velocity, the RMS fluctuating velocities, turbulence parameters, and the shapes of the scatterers are considered. Complications with these determinations are discussed. It is seen throughout that a detailed understanding of the shape and cause of the scatterers is important in order to make better determinations of these various quantities. Finally, some other parameters, which are less easily acquired, are considered. For example, it is noted that momentum fluxes due to buoyancy waves and turbulence can be determined, and on occasions radars can be used to determine stratospheric diffusion coefficients and even temperature profiles in the atmosphere.

  10. Loading effects in GPS vertical displacement time series

    NASA Astrophysics Data System (ADS)

    Memin, A.; Boy, J. P.; Santamaría-Gómez, A.; Watson, C.; Gravelle, M.; Tregoning, P.

    2015-12-01

    Surface deformations due to loading, with yet no comprehensive representation, account for a significant part of the variability in geodetic time series. We assess effects of loading in GPS vertical displacement time series at several frequency bands. We compare displacement derived from up-to-date loading models to two global sets of positioning time series, and investigate how they are reduced looking at interannual periods (> 2 months), intermediate periods (> 7 days) and the whole spectrum (> 1day). We assess the impact of interannual loading on estimating velocities. We compute atmospheric loading effects using surface pressure fields from the ECMWF. We use the inverted barometer (IB) hypothesis valid for periods exceeding a week to describe the ocean response to the pressure forcing. We used general circulation ocean model (ECCO and GLORYS) to account for wind, heat and fresh water flux. We separately use the Toulouse Unstructured Grid Ocean model (TUGO-m), forced by air pressure and winds, to represent the dynamics of the ocean response at high frequencies. The continental water storage is described using GLDAS/Noah and MERRA-land models. Non-hydrology loading reduces the variability of the observed vertical displacement differently according to the frequency band. The hydrology loading leads to a further reduction mostly at annual periods. ECMWF+TUGO-m better agrees with vertical surface motion than the ECMWF+IB model at all frequencies. The interannual deformation is time-correlated at most of the locations. It is adequately described by a power-law process of spectral index varying from -1.5 to -0.2. Depending on the power-law parameters, the predicted non-linear deformation due to mass loading variations leads to vertical velocity biases up to 0.7 mm/yr when estimated from 5 years of continuous observations. The maximum velocity bias can reach up to 1 mm/yr in regions around the southern Tropical band.

  11. Effect of a circular hole on the buckling of cylindrical shells loaded by axial compression.

    NASA Technical Reports Server (NTRS)

    Starnes, J. H., Jr.

    1972-01-01

    An experimental and analytical investigation of the effect of a circular hole on the buckling of thin cylindrical shells under axial compression was carried out. The experimental results were obtained from tests performed on seamless electroformed copper shells and Mylar shells with a lap joint seam. These results indicated that the character of the shell buckling was dependent on a parameter which is proportional to the hole radius divided by the square root of the product of the shell radius and thickness. For small values of this parameter, there was no apparent effect of the hole on the buckling load. For slightly larger values of the parameter, the shells still buckled into a general collapse configuration, but the buckling loads were sharply reduced as the parameter increased. For still larger values of the parameter, the buckling loads were further reduced, and the shells buckled into a stable local buckling configuration.

  12. Peak load management: Potential options

    SciTech Connect

    Englin, J.E.; De Steese, J.G.; Schultz, R.W.; Kellogg, M.A.

    1989-10-01

    This report reviews options that may be alternatives to transmission construction (ATT) applicable both generally and at specific locations in the service area of the Bonneville Power Administration (BPA). Some of these options have potential as specific alternatives to the Shelton-Fairmount 230-kV Reinforcement Project, which is the focus of this study. A listing of 31 peak load management (PLM) options is included. Estimated costs and normalized hourly load shapes, corresponding to the respective base load and controlled load cases, are considered for 15 of the above options. A summary page is presented for each of these options, grouped with respect to its applicability in the residential, commercial, industrial, and agricultural sectors. The report contains comments on PLM measures for which load shape management characteristics are not yet available. These comments address the potential relevance of the options and the possible difficulty that may be encountered in characterizing their value should be of interest in this investigation. The report also identifies options that could improve the efficiency of the three customer utility distribution systems supplied by the Shelton-Fairmount Reinforcement Project. Potential cogeneration options in the Olympic Peninsula are also discussed. These discussions focus on the options that appear to be most promising on the Olympic Peninsula. Finally, a short list of options is recommended for investigation in the next phase of this study. 9 refs., 24 tabs.

  13. A gravity loading countermeasure skinsuit

    NASA Astrophysics Data System (ADS)

    Waldie, James M.; Newman, Dava J.

    2011-04-01

    Despite the use of several countermeasures, significant physiological deconditioning still occurs during long duration spaceflight. Bone loss - primarily due to the absence of loading in microgravity - is perhaps the greatest challenge to resolve. This paper describes a conceptual Gravity Loading Countermeasure Skinsuit (GLCS) that induces loading on the body to mimic standing and - when integrated with other countermeasures - exercising on Earth. Comfort, mobility and other operational issues were explored during a pilot study carried out in parabolic flight for prototype suits worn by three subjects. Compared to the 1- or 2-stage Russian Pingvin Suits, the elastic mesh of the GLCS can create a loading regime that gradually increases in hundreds of stages from the shoulders to the feet, thereby reproducing the weight-bearing regime normally imparted by gravity with much higher resolution. Modelling shows that the skinsuit requires less than 10 mmHg (1.3 kPa) of compression for three subjects of varied gender, height and mass. Negligible mobility restriction and excellent comfort properties were found during the parabolic flights, which suggests that crewmembers should be able to work normally, exercise or sleep while wearing the suit. The suit may also serve as a practical 1 g harness for exercise countermeasures and vibration applications to improve dynamic loading.

  14. Probabilistic load simulation: Code development status

    NASA Technical Reports Server (NTRS)

    Newell, J. F.; Ho, H.

    1991-01-01

    The objective of the Composite Load Spectra (CLS) project is to develop generic load models to simulate the composite load spectra that are included in space propulsion system components. The probabilistic loads thus generated are part of the probabilistic design analysis (PDA) of a space propulsion system that also includes probabilistic structural analyses, reliability, and risk evaluations. Probabilistic load simulation for space propulsion systems demands sophisticated probabilistic methodology and requires large amounts of load information and engineering data. The CLS approach is to implement a knowledge based system coupled with a probabilistic load simulation module. The knowledge base manages and furnishes load information and expertise and sets up the simulation runs. The load simulation module performs the numerical computation to generate the probabilistic loads with load information supplied from the CLS knowledge base.

  15. Probabilistic load simulation: Code development status

    NASA Astrophysics Data System (ADS)

    Newell, J. F.; Ho, H.

    1991-05-01

    The objective of the Composite Load Spectra (CLS) project is to develop generic load models to simulate the composite load spectra that are included in space propulsion system components. The probabilistic loads thus generated are part of the probabilistic design analysis (PDA) of a space propulsion system that also includes probabilistic structural analyses, reliability, and risk evaluations. Probabilistic load simulation for space propulsion systems demands sophisticated probabilistic methodology and requires large amounts of load information and engineering data. The CLS approach is to implement a knowledge based system coupled with a probabilistic load simulation module. The knowledge base manages and furnishes load information and expertise and sets up the simulation runs. The load simulation module performs the numerical computation to generate the probabilistic loads with load information supplied from the CLS knowledge base.

  16. The use of ultrasonic signals and optical method to estimate the damage of materials after fatigue loading

    NASA Astrophysics Data System (ADS)

    Mishakin, V. V.; Mitenkov, F. M.; Klyushnikov, V. A.; Danilova, N. V.

    2010-12-01

    The influence of fatigue load of steels on parameters of ultrasonic and microplastic characteristics has been studied. A phenomenological theory, which connects process of damage accumulation (before appearance of crack) under fatigue loading with acoustic parameters and microplastic parameters, has been developed. Experimental studies showed that the combination of nondestructive methods of control (acoustical and optical) allows one to estimate the state of materials at an early stage of destruction in both low-cycle and high-cycle areas.

  17. An electricity price model with consideration to load and gas price effects.

    PubMed

    Huang, Min-xiang; Tao, Xiao-hu; Han, Zhen-xiang

    2003-01-01

    Some characteristics of the electricity load and prices are studied, and the relationship between electricity prices and gas (fuel) prices is analyzed in this paper. Because electricity prices are strongly dependent on load and gas prices, the authors constructed a model for electricity prices based on the effects of these two factors; and used the Geometric Mean Reversion Brownian Motion (GMRBM) model to describe the electricity load process, and a Geometric Brownian Motion(GBM) model to describe the gas prices; deduced the price stochastic process model based on the above load model and gas price model. This paper also presents methods for parameters estimation, and proposes some methods to solve the model.

  18. Operating experience with high beam currents and transient beam loading in the SLC damping rings

    SciTech Connect

    Minty, M.G.; Akre, R.; Krejcik, P.; Siemann, R.H.

    1995-06-01

    During the 1994 SLC run the nominal operating intensity in the damping rings was raised from 3.5 {times} 10{sup 10} to greater than 4 {times} 10{sup 10} particles per bunch (ppb). Stricter regulation of rf system parameters was required to maintain stability of the rf system and particle beam. Improvements were made in the feedback loops which control the cavity amplitude and loading angles. Compensation for beam loading was also required to prevent klystron saturation during repetition rate changes. To minimize the effects of transient loading on the rf system, the gain of the direct rf feedback loop and the loading angles were optimized.

  19. Multiaxial fatigue behavior of tubular joints under variable amplitude loading conditions

    SciTech Connect

    Abel, A.; Wu, S.; Yu, X.

    1994-12-31

    An analytical approach has been developed for the study of fatigue life of tubular joints used in offshore structures when random loading conditions are applied. The method is based on linear elastic fracture mechanics and surface fatigue crack propagation. Using the line-spring element method, stress intensity factors of a part-through surface crack are computed. Crack propagation under random loading conditions with distribution parameters is calculated leading to fatigue life prediction if the statistical characteristics of random loading conditions are known. This method can be also used in predicting the remaining lives of tubular joints when cracks are detected and random loading conditions are applied.

  20. Games with fuzzy parameters

    NASA Astrophysics Data System (ADS)

    Messaoud, Deghdak

    2010-11-01

    In this paper, we study the existence of equilibrium in non-cooperative game with fuzzy parameters. We generalize te results of Larbani and Kacher(2008, 2009) in infinite dimentional spaces. The proof is based on the Browder-Fan fixed point theorem.

  1. Phenological Parameters Estimation Tool

    NASA Technical Reports Server (NTRS)

    McKellip, Rodney D.; Ross, Kenton W.; Spruce, Joseph P.; Smoot, James C.; Ryan, Robert E.; Gasser, Gerald E.; Prados, Donald L.; Vaughan, Ronald D.

    2010-01-01

    The Phenological Parameters Estimation Tool (PPET) is a set of algorithms implemented in MATLAB that estimates key vegetative phenological parameters. For a given year, the PPET software package takes in temporally processed vegetation index data (3D spatio-temporal arrays) generated by the time series product tool (TSPT) and outputs spatial grids (2D arrays) of vegetation phenological parameters. As a precursor to PPET, the TSPT uses quality information for each pixel of each date to remove bad or suspect data, and then interpolates and digitally fills data voids in the time series to produce a continuous, smoothed vegetation index product. During processing, the TSPT displays NDVI (Normalized Difference Vegetation Index) time series plots and images from the temporally processed pixels. Both the TSPT and PPET currently use moderate resolution imaging spectroradiometer (MODIS) satellite multispectral data as a default, but each software package is modifiable and could be used with any high-temporal-rate remote sensing data collection system that is capable of producing vegetation indices. Raw MODIS data from the Aqua and Terra satellites is processed using the TSPT to generate a filtered time series data product. The PPET then uses the TSPT output to generate phenological parameters for desired locations. PPET output data tiles are mosaicked into a Conterminous United States (CONUS) data layer using ERDAS IMAGINE, or equivalent software package. Mosaics of the vegetation phenology data products are then reprojected to the desired map projection using ERDAS IMAGINE

  2. The Parameters of Postmodernism.

    ERIC Educational Resources Information Center

    Zurbrugg, Nicholas

    Hypothesizing that the tendency to define postmodern culture negatively derives from overliteral and undercritical responses to European theorists, this book of essays identifies the wide parameters of postmodernism. The book demonstrates that the literary and artistic temper of the postmodern condition in Europe and America cannot adequately be…

  3. Determining safe limits for significant task parameters during manual lifting.

    PubMed

    Singh, Ravindra Pratrap; Batish, Ajay; Singh, Tejinder Pal

    2014-04-01

    This experimental study investigated the effect of lifting task parameters (i.e., lifting weight, frequency, coupling, asymmetric angle, and vertical, horizontal, and travel distances) for various dynamic human lifting activities on the ground reaction forces of workers. Ten male workers loaded containers from different levels asymmetrically during experimental trials. The experimental design evolved using Taguchi's Fractional Factorial Experiments. Three factors (lifting weight, frequency, and vertical distance) were observed to be significant. The results showed that vertical reaction forces increase when workers lift weight from floor to shoulder height frequently. It was also observed that instantaneous loading rate increases with more weight, vertical distance, and frequency; a significant extra loading rate is required to change the lower level of load, frequency, and vertical distance to higher levels. Safe limits for significant factors were determined to result in optimal performance of the manual lifting task.

  4. Fifty years of genetic load

    SciTech Connect

    Wallace, B.

    1991-01-01

    This book discusses the radiation effects on Drosophila. It was originally thought that irradiating Drosophila would decrease the average fitness of the population, thereby leading to information about the detrimental effects of mutations. Surprisingly, the fitness of the irradiated population turned out to be higher than that of the control population. The original motivation for the experiment was as a test of genetic load theory. The average fitness of a population is depressed by deleterious alleles held in the population by the balance between mutation and natural selection. The depression is called the genetic load of the population. The load dose not depend on the magnitude of the deleterious effect of alleles, but only on the mutation rate.

  5. Symplastic phloem loading in poplar.

    PubMed

    Zhang, Cankui; Han, Lu; Slewinski, Thomas L; Sun, Jianlei; Zhang, Jing; Wang, Zeng-Yu; Turgeon, Robert

    2014-09-01

    Sap is driven through phloem sieve tubes by an osmotically generated pressure gradient between source and sink tissues. In many plants, source pressure results from thermodynamically active loading in which energy is used to transfer sucrose (Suc) from mesophyll cells to the phloem of leaf minor veins against a concentration gradient. However, in some species, almost all trees, correlative evidence suggests that sugar migrates passively through plasmodesmata from mesophyll cells into the sieve elements. The possibility of alternate loading mechanisms has important ramifications for the regulation of phloem transport and source-sink interactions. Here, we provide experimental evidence that, in gray poplar (Populus tremula × Populus alba), Suc enters the phloem through plasmodesmata. Transgenic plants were generated with yeast invertase in the cell walls to prevent Suc loading by this route. The constructs were driven either by the constitutive 35S promoter or the minor vein-specific galactinol synthase promoter. Transgenic plants grew at the same rate as the wild type without symptoms of loading inhibition, such as accumulation of carbohydrates or leaf chlorosis. Rates of photosynthesis were normal. In contrast, alfalfa (Medicago sativa) plants, which have limited numbers of plasmodesmata between mesophyll and phloem, displayed typical symptoms of loading inhibition when transformed with the same DNA constructs. The results are consistent with passive loading of Suc through plasmodesmata in poplar. We also noted defense-related symptoms in leaves of transgenic poplar when the plants were abruptly exposed to excessively high temperatures, adding to evidence that hexose is involved in triggering the hypersensitive response.

  6. Airloads research study. Volume 1: Flight test loads acquisition

    NASA Technical Reports Server (NTRS)

    Bartlett, M. D.; Feltz, T. F.; Olsen, A. D., Jr.; Smith, D. B.; Wildermuth, P. F.

    1984-01-01

    The acquisition of B-1 aircraft flight loads data for use in subsequent tasks of the Airloads Research Study is described. The basic intent is to utilize data acquired during B-1 aircraft tests, analyze these data beyond the scope of Air Force requirements, and prepare research reports that will add to the technology base for future large flexible aircraft. Flight test data obtained during the airloads survey program included condition-describing parameters, surface pressures, strain gage outputs, and loads derived from pressure and strain gauges. Descriptions of the instrumentation, data processing, and flight load survey program are included. Data from windup-turn and steady yaw maneuvers cover a Mach number range from 0.7 to 2.0 for a wing sweep position of 67.5 deg.

  7. Modeling the responses of TSM resonators under various loading conditions

    SciTech Connect

    BANDEY,HELEN L.; MARTIN,STEPHEN J.; CERNOSEK,RICHARD W.; HILLMAN,A. ROBERT

    1999-03-01

    The authors developed a general model that describes the electrical responses of thickness shear mode resonators subject to a variety of surface conditions. The model incorporates a physically diverse set of single component loadings, including rigid solids, viscoelastic media, and fluids (Newtonian or Maxwellian). The model allows any number of these components to be combined in any configuration. Such multiple loadings are representative of a variety of physical situations encountered in electrochemical and other liquid phase applications, as well as gas phase applications. In the general case, the response of the composite load is not a linear combination of the individual component responses. The authors discuss application of the model in a qualitative diagnostic fashion to gain insight into the nature of the interfacial structure, and in a quantitative fashion to extract appropriate physical parameters such as liquid viscosity and density, and polymer shear moduli.

  8. Multi-band Monopole Antennas Loaded with Metamaterial TL

    NASA Astrophysics Data System (ADS)

    Song, Zhi-jie; Liang, Jian-gang

    2015-05-01

    A novel metamaterial transmission line (TL) by loading complementary single Archimedean spiral resonator pair (CSASRP) is investigated and used to design a set of multi-frequency monopole antennas. The particularity is that the CSASRP which features dual-shunt branches in the equivalent circuit model is directly etched in the signal strip. By smartly controlling the element parameters, three antennas are designed and one of them covering UMTS and Bluetooth bands is fabricated and measured. The antenna exhibits impedance matching better than -10 dB and normal monopolar radiation patterns at working bands of 1.9-2.22 and 2.38-2.5 GHz. Moreover, the loaded element also contributes to the radiation, which is the major advantage of this prescription over previous lumped-element loadings. The proposed antenna is also more compact over previous designs.

  9. Influence of plasma loading in a hybrid muon cooling channel

    SciTech Connect

    Freemire, B.; Stratakis, D.; Yonehara, K.

    2015-05-03

    In a hybrid 6D cooling channel, cooling is accomplished by reducing the beam momentum through ionization energy loss in wedge absorbers and replenishing the momentum loss in the longitudinal direction with gas-filled rf cavities. While the gas acts as a buffer to prevent rf breakdown, gas ionization also occurs as the beam passes through the pressurized cavity. The resulting plasma may gain substantial energy from the rf electric field which it can transfer via collisions to the gas, an effect known as plasma loading. In this paper, we investigate the influence of plasma loading on the cooling performance of a rectilinear hybrid channel. With the aid of numerical simulations we examine the sensitivity in cooling performance and plasma loading to key parameters such as the rf gradient and gas pressure.

  10. CMP dummy pattern based on VSB writer load

    NASA Astrophysics Data System (ADS)

    Sakata, Wakahiko; Osawa, Isaku; Narukawa, Shogo; Takikawa, Tadahiko; Mohri, Hiroshi

    2010-05-01

    The load of VSB-EB mask writers has significantly increased since particularly RET/OPC and CMP dummy pattern generation technologies were widely adopted into designs at advanced nodes, with the result that the volume of mask data patterns was increased exponentially. In order to reduce the load of VSB mask writer, we've focused on CMP dummy patterns and developed a method of reducing CMP dummy pattern, which can smartly write CMP dummy patterns without not only deteriorating the CMP effects by them and also increasing the total number of the mask writer's shot count. To that end, we are aiming to establish a VSB-mask-writer-friendly CMP dummy pattern generation flow with CMP simulator developers by providing a mask writer parameter for them. This paper shows the first experimental results of our mask writer's load reduction work.

  11. Passively Shunted Piezoelectric Damping of Centrifugally-Loaded Plates

    NASA Technical Reports Server (NTRS)

    Duffy, Kirsten P.; Provenza, Andrew J.; Trudell, Jeffrey J.; Min, James B.

    2009-01-01

    Researchers at NASA Glenn Research Center have been investigating shunted piezoelectric circuits as potential damping treatments for turbomachinery rotor blades. This effort seeks to determine the effects of centrifugal loading on passively-shunted piezoelectric - damped plates. Passive shunt circuit parameters are optimized for the plate's third bending mode. Tests are performed both non-spinning and in the Dynamic Spin Facility to verify the analysis, and to determine the effectiveness of the damping under centrifugal loading. Results show that a resistive shunt circuit will reduce resonant vibration for this configuration. However, a tuned shunt circuit will be required to achieve the desired damping level. The analysis and testing address several issues with passive shunt circuit implementation in a rotating system, including piezoelectric material integrity under centrifugal loading, shunt circuit implementation, and tip mode damping.

  12. Thermal-structural combined loads design criteria study

    NASA Technical Reports Server (NTRS)

    Deriugin, V.; Brogren, E. W.; Jaeck, C. L.; Brown, A. L.; Clingan, B. E.

    1972-01-01

    A study was conducted to determine methodology for combining thermal structural loads and assessing the effects of the combined loads on the design of a thermal protection system and a hot structure of a high cross range delta wing space shuttle orbiter vehicle. The study presents guidelines for establishing a basis for predicting thermal and pressure environments and for determining limit and ultimate design loads on the vehicle during reentry. Limit trajectories were determined by using dispersions on a representative nominal mission and system parameters expected during the life of the vehicle. Nine chosen locations on the vehicle surface having TPS or hot structures were examined, and weight sensitivity analyses were performed for each location.

  13. Analysis of Modeling Parameters on Threaded Screws.

    SciTech Connect

    Vigil, Miquela S.; Brake, Matthew Robert; Vangoethem, Douglas

    2015-06-01

    Assembled mechanical systems often contain a large number of bolted connections. These bolted connections (joints) are integral aspects of the load path for structural dynamics, and, consequently, are paramount for calculating a structure's stiffness and energy dissipation prop- erties. However, analysts have not found the optimal method to model appropriately these bolted joints. The complexity of the screw geometry cause issues when generating a mesh of the model. This paper will explore different approaches to model a screw-substrate connec- tion. Model parameters such as mesh continuity, node alignment, wedge angles, and thread to body element size ratios are examined. The results of this study will give analysts a better understanding of the influences of these parameters and will aide in finding the optimal method to model bolted connections.

  14. Evaluation of the Hinge Moment and Normal Force Aerodynamic Loads from a Seamless Adaptive Compliant Trailing Edge Flap in Flight

    NASA Technical Reports Server (NTRS)

    Miller, Eric J.; Cruz, Josue; Lung, Shun-Fat; Kota, Sridhar; Ervin, Gregory; Lu, Kerr-Jia; Flick, Pete

    2016-01-01

    A seamless adaptive compliant trailing edge (ACTE) flap was demonstrated in flight on a Gulfstream III aircraft at the NASA Armstrong Flight Research Center. The trailing edge flap was deflected between minus 2 deg up and plus 30 deg down in flight. The safety-of-flight parameters for the ACTE flap experiment require that flap-to-wing interface loads be sensed and monitored in real time to ensure that the structural load limits of the wing are not exceeded. The attachment fittings connecting the flap to the aircraft wing rear spar were instrumented with strain gages and calibrated using known loads for measuring hinge moment and normal force loads in flight. The safety-of-flight parameters for the ACTE flap experiment require that flap-to-wing interface loads be sensed and monitored in real time to ensure that the structural load limits of the wing are not exceeded. The attachment fittings connecting the flap to the aircraft wing rear spar were instrumented with strain gages and calibrated using known loads for measuring hinge moment and normal force loads in flight. The interface hardware instrumentation layout and load calibration are discussed. Twenty-one applied calibration test load cases were developed for each individual fitting. The 2-sigma residual errors for the hinge moment was calculated to be 2.4 percent, and for normal force was calculated to be 7.3 percent. The hinge moment and normal force generated by the ACTE flap with a hinge point located at 26-percent wing chord were measured during steady state and symmetric pitch maneuvers. The loads predicted from analysis were compared to the loads observed in flight. The hinge moment loads showed good agreement with the flight loads while the normal force loads calculated from analysis were over-predicted by approximately 20 percent. Normal force and hinge moment loads calculated from the pressure sensors located on the ACTE showed good agreement with the loads calculated from the installed strain gages.

  15. Load and Rate of Change of Load Detection System.

    DTIC Science & Technology

    The present invention relates to a system for detecting and recording the level and rate of change of landing loads in the struts of aircraft landing...to a minimum pressure to record the level and rate of change of pressure detected by the sensor.

  16. Differences in Obesity Rates Among Minority and White Women: The Latent Role of Maternal Stress.

    PubMed

    Patchen, Loral; Rebok, George; Astone, Nan M

    2016-07-01

    White and minority women experience different rates of obesity in the United States. Yet our understanding of the dynamics that give rise to this gap remains limited. This article presents a conceptual framework that considers pathways leading to these different rates. It draws upon the life-course perspective, allostatic load, and the weathering hypothesis to identify pathways linking childbearing, stress, and obesity. This conceptual framework extends prior work by identifying age at first birth as an important parameter that influences these pathways. Empirical evidence to test these pathways is needed.

  17. Analysis of high load dampers

    NASA Technical Reports Server (NTRS)

    Bhat, S. T.; Buono, D. F.; Hibner, D. H.

    1981-01-01

    High load damping requirements for modern jet engines are discussed. The design of damping systems which could satisfy these requirements is also discusseed. In order to evaluate high load damping requirements, engines in three major classes were studied; large transport engines, small general aviation engines, and military engines. Four damper concepts applicable to these engines were evaluated; multi-ring, cartridge, curved beam, and viscous/friction. The most promising damper concept was selected for each engine and performance was assessed relative to conventional dampers and in light of projected damping requirements for advanced jet engines.

  18. Material behavior under complex loading

    SciTech Connect

    Breuer, H.J.; Raule, G.; Rodig, M.

    1984-09-01

    Studies of material behavior under complex loading form a bridge between standard material testing methods and the stress analysis calculations for reactor components at high temperatures. The aim of these studies is to determine the influence of typical load change sequences on material properties, to derive the equations required for stress analyses, to carry out tests under multiaxial conditions, and to investigate the structural deformation mechanisms of creep buckling and ratcheting. The present state of the investigations within the high-temperature gas-cooled reactor materials program is described, with emphasis on the experimental apparatus, the scope of the program, and the initial results obtained.

  19. Method for loading resin beds

    DOEpatents

    Notz, Karl J.; Rainey, Robert H.; Greene, Charles W.; Shockley, William E.

    1978-01-01

    An improved method of preparing nuclear reactor fuel by carbonizing a uranium loaded cation exchange resin provided by contacting a H.sup.+ loaded resin with a uranyl nitrate solution deficient in nitrate, comprises providing the nitrate deficient solution by a method comprising the steps of reacting in a reaction zone maintained between about 145.degree.-200.degree. C, a first aqueous component comprising a uranyl nitrate solution having a boiling point of at least 145.degree. C with a second aqueous component to provide a gaseous phase containing HNO.sub.3 and a reaction product comprising an aqueous uranyl nitrate solution deficient in nitrate.

  20. Dynamic load identification for stochastic structures based on Gegenbauer polynomial approximation and regularization method

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Sun, Xingsheng; Han, Xu; Jiang, Chao; Yu, Dejie

    2015-05-01

    Based on the Gegenbauer polynomial expansion theory and regularization method, an analytical method is proposed to identify dynamic loads acting on stochastic structures. Dynamic loads are expressed as functions of time and random parameters in time domain and the forward model of dynamic load identification is established through the discretized convolution integral of loads and the corresponding unit-pulse response functions of system. Random parameters are approximated through the random variables with λ-probability density function (PDFs) or their derivative PDFs. For this kind of random variables, Gegenbauer polynomial expansion is the unique correct choice to transform the problem of load identification for a stochastic structure into its equivalent deterministic system. Just via its equivalent deterministic system, the load identification problem of a stochastic structure can be solved by any available deterministic methods. With measured responses containing noise, the improved regularization operator is adopted to overcome the ill-posedness of load reconstruction and to obtain the stable and approximate solutions of certain inverse problems and the valid assessments of the statistics of identified loads. Numerical simulations demonstrate that with regard to stochastic structures, the identification and assessment of dynamic loads are achieved steadily and effectively by the presented method.

  1. [Physiological-occupational assessment of acoustic load with equal energy but different time and informational characteristics].

    PubMed

    Suvorov, G A; Shkarinov, L N; Kravchenko, O K; Kur'erov, N N

    1999-01-01

    The article deals with results of experimental study comparing effects of 4 types of acoustic load--noise (constant and impulse) and music (electronic symphonic one and rap)--on hearing sensitivity, processes in nervous system and subjective evaluation. All types of acoustic load were equal in energy (on evaluation according to equivalent level during the experiment). The study included 2 levels of load--90 and 95 dB. The differences revealed demonstrate importance of impulse parameters of noise and musical load for reactions of acoustic analyzer and central nervous system. The experiments show that evaluation of harm caused by temporary and impulse noises should be based not only on assessment of specific (hearing) function, but also on parameters of central nervous system state. The authors found that music of certain acoustic and informational parameters may harm hearing function.

  2. 46 CFR 122.335 - Loading doors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Loading doors. 122.335 Section 122.335 Shipping COAST... Requirements § 122.335 Loading doors. (a) Except as allowed by paragraph (b) of this section, the master of a vessel fitted with loading doors shall assure that all loading doors are closed and secured during...

  3. 14 CFR 23.537 - Seawing loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Seawing loads. 23.537 Section 23.537... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.537 Seawing loads. Seawing design loads must be based on applicable test data. Emergency Landing Conditions...

  4. 14 CFR 27.341 - Gust loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Gust loads. 27.341 Section 27.341... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.341 Gust loads. The rotorcraft must be designed to withstand, at each critical airspeed including hovering, the loads resulting from...

  5. 14 CFR 29.301 - Loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Loads. 29.301 Section 29.301 Aeronautics... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements General § 29.301 Loads. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and...

  6. 14 CFR 27.301 - Loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Loads. 27.301 Section 27.301 Aeronautics... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements General § 27.301 Loads. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and...

  7. 14 CFR 23.537 - Seawing loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Seawing loads. 23.537 Section 23.537... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.537 Seawing loads. Seawing design loads must be based on applicable test data. Emergency Landing Conditions...

  8. 14 CFR 29.301 - Loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Loads. 29.301 Section 29.301 Aeronautics... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements General § 29.301 Loads. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and...

  9. 14 CFR 29.301 - Loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Loads. 29.301 Section 29.301 Aeronautics... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements General § 29.301 Loads. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and...

  10. 14 CFR 27.301 - Loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Loads. 27.301 Section 27.301 Aeronautics... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements General § 27.301 Loads. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and...

  11. 14 CFR 27.865 - External loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false External loads. 27.865 Section 27.865... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction External Loads § 27.865 External loads. (a) It must be shown by analysis, test, or both, that the rotorcraft external load attaching means...

  12. 14 CFR 27.301 - Loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Loads. 27.301 Section 27.301 Aeronautics... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements General § 27.301 Loads. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and...

  13. 46 CFR 169.689 - Demand loads.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Demand loads. 169.689 Section 169.689 Shipping COAST... Electrical Electrical Installations on Vessels of 100 Gross Tons and Over § 169.689 Demand loads. Demand loads must meet § 111.60-7 of this chapter except that smaller demand loads for motor feeders...

  14. 14 CFR 23.537 - Seawing loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Seawing loads. 23.537 Section 23.537... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.537 Seawing loads. Seawing design loads must be based on applicable test data. Emergency Landing Conditions...

  15. 14 CFR 29.341 - Gust loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Gust loads. 29.341 Section 29.341... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.341 Gust loads. Each rotorcraft must be designed to withstand, at each critical airspeed including hovering, the loads...

  16. 14 CFR 23.537 - Seawing loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Seawing loads. 23.537 Section 23.537... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.537 Seawing loads. Seawing design loads must be based on applicable test data. Emergency Landing Conditions...

  17. 14 CFR 29.865 - External loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false External loads. 29.865 Section 29.865... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction External Loads § 29.865 External loads. (a) It must be shown by analysis, test, or both, that the rotorcraft external load attaching means...

  18. 14 CFR 29.865 - External loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false External loads. 29.865 Section 29.865... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction External Loads § 29.865 External loads. (a) It must be shown by analysis, test, or both, that the rotorcraft external load attaching means...

  19. 14 CFR 27.301 - Loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Loads. 27.301 Section 27.301 Aeronautics... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements General § 27.301 Loads. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and...

  20. 14 CFR 29.341 - Gust loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Gust loads. 29.341 Section 29.341... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.341 Gust loads. Each rotorcraft must be designed to withstand, at each critical airspeed including hovering, the loads...

  1. 14 CFR 29.341 - Gust loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Gust loads. 29.341 Section 29.341... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.341 Gust loads. Each rotorcraft must be designed to withstand, at each critical airspeed including hovering, the loads...

  2. 14 CFR 27.341 - Gust loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Gust loads. 27.341 Section 27.341... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.341 Gust loads. The rotorcraft must be designed to withstand, at each critical airspeed including hovering, the loads resulting from...

  3. 14 CFR 29.341 - Gust loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Gust loads. 29.341 Section 29.341... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.341 Gust loads. Each rotorcraft must be designed to withstand, at each critical airspeed including hovering, the loads...

  4. 14 CFR 29.301 - Loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Loads. 29.301 Section 29.301 Aeronautics... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements General § 29.301 Loads. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and...

  5. 14 CFR 29.301 - Loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Loads. 29.301 Section 29.301 Aeronautics... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements General § 29.301 Loads. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and...

  6. 14 CFR 29.865 - External loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false External loads. 29.865 Section 29.865... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction External Loads § 29.865 External loads. (a) It must be shown by analysis, test, or both, that the rotorcraft external load attaching means...

  7. 14 CFR 23.537 - Seawing loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Seawing loads. 23.537 Section 23.537... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.537 Seawing loads. Seawing design loads must be based on applicable test data. Emergency Landing Conditions...

  8. 14 CFR 27.341 - Gust loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Gust loads. 27.341 Section 27.341... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.341 Gust loads. The rotorcraft must be designed to withstand, at each critical airspeed including hovering, the loads resulting from...

  9. 14 CFR 27.865 - External loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false External loads. 27.865 Section 27.865... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction External Loads § 27.865 External loads. (a) It must be shown by analysis, test, or both, that the rotorcraft external load attaching means...

  10. 14 CFR 27.341 - Gust loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Gust loads. 27.341 Section 27.341... STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.341 Gust loads. The rotorcraft must be designed to withstand, at each critical airspeed including hovering, the loads resulting from...

  11. 14 CFR 27.865 - External loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false External loads. 27.865 Section 27.865... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction External Loads § 27.865 External loads. (a) It must be shown by analysis, test, or both, that the rotorcraft external load attaching means...

  12. 46 CFR 169.689 - Demand loads.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Demand loads. 169.689 Section 169.689 Shipping COAST... Electrical Electrical Installations on Vessels of 100 Gross Tons and Over § 169.689 Demand loads. Demand loads must meet § 111.60-7 of this chapter except that smaller demand loads for motor feeders...

  13. 14 CFR 29.341 - Gust loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Gust loads. 29.341 Section 29.341... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 29.341 Gust loads. Each rotorcraft must be designed to withstand, at each critical airspeed including hovering, the loads...

  14. A novel two-axis load sensor designed for in situ scratch testing inside scanning electron microscopes.

    PubMed

    Huang, Hu; Zhao, Hongwei; Wu, Boda; Wan, Shunguang; Shi, Chengli

    2013-02-18

    Because of a lack of available miniaturized multiaxial load sensors to measure the normal load and the lateral load simultaneously, quantitative in situ scratch devices inside scanning electron microscopes and the transmission electron microscopes have barely been developed up to now. A novel two-axis load sensor was designed in this paper. With an I-shaped structure, the sensor has the function of measuring the lateral load and the normal load simultaneously, and at the same time it has compact dimensions. Finite element simulations were carried out to evaluate stiffness and modal characteristics. A decoupling algorithm was proposed to resolve the cross-coupling between the two-axis loads. Natural frequency of the sensor was tested. Linearity and decoupling parameters were obtained from the calibration experiments, which indicate that the sensor has good linearity and the cross-coupling between the two axes is not strong. Via the decoupling algorithm and the corresponding decoupling parameters, simultaneous measurement of the lateral load and the normal load can be realized via the developed two-axis load sensor. Preliminary applications of the load sensor for scratch testing indicate that the load sensor can work well during the scratch testing. Taking advantage of the compact structure, it has the potential ability for applications in quantitative in situ scratch testing inside SEMs.

  15. Strain Gage Load Calibration of the Wing Interface Fittings for the Adaptive Compliant Trailing Edge Flap Flight Test

    NASA Technical Reports Server (NTRS)

    Miller, Eric J.; Holguin, Andrew C.; Cruz, Josue; Lokos, William A.

    2014-01-01

    The safety-of-flight parameters for the Adaptive Compliant Trailing Edge (ACTE) flap experiment require that flap-to-wing interface loads be sensed and monitored in real time to ensure that the structural load limits of the wing are not exceeded. This paper discusses the strain gage load calibration testing and load equation derivation methodology for the ACTE interface fittings. Both the left and right wing flap interfaces were monitored; each contained four uniquely designed and instrumented flap interface fittings. The interface hardware design and instrumentation layout are discussed. Twenty-one applied test load cases were developed using the predicted in-flight loads. Pre-test predictions of strain gage responses were produced using finite element method models of the interface fittings. Predicted and measured test strains are presented. A load testing rig and three hydraulic jacks were used to apply combinations of shear, bending, and axial loads to the interface fittings. Hardware deflections under load were measured using photogrammetry and transducers. Due to deflections in the interface fitting hardware and test rig, finite element model techniques were used to calculate the reaction loads throughout the applied load range, taking into account the elastically-deformed geometry. The primary load equations were selected based on multiple calibration metrics. An independent set of validation cases was used to validate each derived equation. The 2-sigma residual errors for the shear loads were less than eight percent of the full-scale calibration load; the 2-sigma residual errors for the bending moment loads were less than three percent of the full-scale calibration load. The derived load equations for shear, bending, and axial loads are presented, with the calculated errors for both the calibration cases and the independent validation load cases.

  16. Stiffness characteristics of airfoils under pulse loading

    NASA Astrophysics Data System (ADS)

    Turner, Kevin Eugene

    The turbomachinery industry continually struggles with the adverse effects of contact rubs between airfoils and casings. The key parameter controlling the severity of a given rub event is the contact load produced when the airfoil tips incur into the casing. These highly non-linear and transient forces are difficult to calculate and their effects on the static and rotating components are not well understood. To help provide this insight, experimental and analytical capabilities have been established and exercised through an alliance between GE Aviation and The Ohio State University Gas Turbine Laboratory. One of the early findings of the program is the influence of blade flexibility on the physics of rub events. The core focus of the work presented in this dissertation is to quantify the influence of airfoil flexibility through a novel modeling approach that is based on the relationship between applied force duration and maximum tip deflection. This relationship is initially established using a series of forward, non-linear and transient analyses in which simulated impulse rub loads are applied. This procedure, although effective, is highly inefficient and costly to conduct by requiring numerous explicit simulations. To alleviate this issue, a simplified model, named the pulse magnification model, is developed that only requires a modal analysis and a static analyses to fully describe how the airfoil stiffness changes with respect to load duration. Results from the pulse magnification model are compared to results from the full transient simulation method and to experimental results, providing sound verification for the use of the modeling approach. Furthermore, a unique and highly efficient method to model airfoil geometries was developed and is outlined in this dissertation. This method produces quality Finite Element airfoil definitions directly from a fully parameterized mathematical model. The effectiveness of this approach is demonstrated by comparing modal

  17. Physical Parameter Eclipse Mapping

    NASA Astrophysics Data System (ADS)

    Vrielmann, S.

    The tomographic method Physical Parameter Eclipse Mapping is a tool to reconstruct spatial distributions of physical parameters (like temperatures and surface densities) in accretion discs of cataclysmic variables. After summarizing the method, we apply it to multi-colour eclipse light curves of various dwarf novae and nova-likes like VZ Scl, IP Peg in outburst, UU Aqr, V2051 Oph and HT Cas in order to derive the temperatures (and surface densities) in the disc, the white dwarf temperature, the disc size, the effective temperatures and the viscosities. The results allows us to establish or refine a physical model for the accretion disc. Our maps of HT Cas and V 2051Oph, for example, indicate that the (quiescent) disc must be structured into a cool, optically thick inner disc sandwiched by hot, optically thin chromospheres. In addition, the disc of HT Cas must be patchy with a covering factor of about 40% caused by magnetic activity in the disc.

  18. Geoengineering design parameters workshop

    SciTech Connect

    St. John, C.M. and Associates, Grand Junction, CO ); Kim, Kunsoo . Rockwell Hanford Operations)

    1985-12-12

    A one-day workshop on the subject of the geotechnical design parameters, in situ stress and rock mass strength, for a nuclear waste repository in basalt was held in Rapid City, South Dakota, on June 25, 1989. A panel comprised of five widely recognized experts in the field of rock mechanics, met to discuss the state of stress at the Hanford Site and the strength of a basalt rock mass. This report summarizes the discussions that took place and presents a set of final position statements developed collaboratively by the panel and the workshop moderator. The report concludes with a set of specific recommendations for future actions considered necessary to adequately define the in situ stress and the rock mass strength at the Hanford Site and to document the position of the Basalt Waste Isolation Project in respect to these two critical design parameters.

  19. Military display performance parameters

    NASA Astrophysics Data System (ADS)

    Desjardins, Daniel D.; Meyer, Frederick

    2012-06-01

    The military display market is analyzed in terms of four of its segments: avionics, vetronics, dismounted soldier, and command and control. Requirements are summarized for a number of technology-driving parameters, to include luminance, night vision imaging system compatibility, gray levels, resolution, dimming range, viewing angle, video capability, altitude, temperature, shock and vibration, etc., for direct-view and virtual-view displays in cockpits and crew stations. Technical specifications are discussed for selected programs.

  20. Predicting the settlement of coarse granular materials under vertical loading

    NASA Astrophysics Data System (ADS)

    Quezada, Juan Carlos; Saussine, Gilles; Breul, Pierre; Radjaï, Farhang

    2014-07-01

    Granular materials are widely used in industrial processes despite their complex and poorly understood mechanical behaviour both in static and dynamic regimes. A prototypical example is the settlement and compaction of a granular bed under vibrational loading. The elementary mechanisms of this process are still unclear and there is presently no established theory or methodology to predict the settlement and its statistical variability. By means of a parametric study, carried out on a full-scale track, and a critical analysis of density relaxation laws, we introduce a novel settlement model in coarse granular materials under cyclic loading. Our extensive experimental data indicate that the settlement process is governed by three independent parameters strongly correlated with the vibration intensity and initial packing fraction. We show that the mean settlement is well predicted by the model with its parameter values extracted from experimental data.

  1. Analysis of concrete containment structures under severe accident loading conditions

    SciTech Connect

    Porter, V.L.

    1993-12-31

    One of the areas of current interest in the nuclear power industry is the response of containment buildings to internal pressures that may exceed design pressure levels. Evaluating the response of structures under these conditions requires computing beyond design load to the ultimate load of the containment. For concrete containments, this requirement means computing through severe concrete cracking and into the regime of wide-spread plastic rebar and/or tendon response. In this regime of material response, an implicit code can have trouble converging. This paper describes some of the author`s experiences with Version 5.2 of ABAQUS Standard and the ABAQUS concrete model in computing the axisymmetric response of a prestressed concrete containment to ultimate global structural failure under high internal pressures. The effects of varying the tension stiffening parameter in the concrete material model and variations of the parameters for the CONTROLS option are discussed.

  2. Predicting the settlement of coarse granular materials under vertical loading.

    PubMed

    Quezada, Juan Carlos; Saussine, Gilles; Breul, Pierre; Radjaï, Farhang

    2014-07-16

    Granular materials are widely used in industrial processes despite their complex and poorly understood mechanical behaviour both in static and dynamic regimes. A prototypical example is the settlement and compaction of a granular bed under vibrational loading. The elementary mechanisms of this process are still unclear and there is presently no established theory or methodology to predict the settlement and its statistical variability. By means of a parametric study, carried out on a full-scale track, and a critical analysis of density relaxation laws, we introduce a novel settlement model in coarse granular materials under cyclic loading. Our extensive experimental data indicate that the settlement process is governed by three independent parameters strongly correlated with the vibration intensity and initial packing fraction. We show that the mean settlement is well predicted by the model with its parameter values extracted from experimental data.

  3. Stress transfer efficiency in model composites under dynamic loading

    NASA Astrophysics Data System (ADS)

    Koimtzoglou, C.; Kostopoulos, V.; Galiotis, C.

    The micromechanics of tension-tension fatigue loading in model single-fibre composite geometries is investigated in this paper. In an attempt to emulate the conditions encountered in full carbon fibre composites, the fibres were prestrained prior to the curing process to ensure that they were free of high residual compressive stresses as a result of resin shrinkage. The resulting specimens were grouped into two categories depending on the level of the initial fibre prestrain (case A low, case B high). The cyclic load is designed to be well below the endurance fatigue limit of the polymer matrix ( 0.6%), and to have a frequency low enough to avoid unwanted thermal post curing. Throughout the preparation procedure, as well as during fatigue loading, the fibre stress (strain) was constantly monitored by means of laser Raman spectroscopy. The fibre axial stress distributions at each fatigue step were converted to interfacial shear stress (ISS) distributions, from which important parameters such as the maximum ISS the system can accommodate, the transfer length for efficient stress built-up and the length required for the attainment of maximum ISS were obtained. The results showed that, up to 2×106 loading cycles, the main parameters which affected the stress transfer efficiency at the interface were the fibre fracture process itself and the viscoelastic behaviour of the matrix material.

  4. Optimize Short Term load Forcasting Anomalous Based Feed Forward Backpropagation

    NASA Astrophysics Data System (ADS)

    Mulyadi, Y.; Abdullah, A. G.; Rohmah, K. A.

    2017-03-01

    This paper contains the Short-Term Load Forecasting (STLF) using artificial neural network especially feed forward back propagation algorithm which is particularly optimized in order to getting a reduced error value result. Electrical load forecasting target is a holiday that hasn’t identical pattern and different from weekday’s pattern, in other words the pattern of holiday load is an anomalous. Under these conditions, the level of forecasting accuracy will be decrease. Hence we need a method that capable to reducing error value in anomalous load forecasting. Learning process of algorithm is supervised or controlled, then some parameters are arranged before performing computation process. Momentum constant a value is set at 0.8 which serve as a reference because it has the greatest converge tendency. Learning rate selection is made up to 2 decimal digits. In addition, hidden layer and input component are tested in several variation of number also. The test result leads to the conclusion that the number of hidden layer impact on the forecasting accuracy and test duration determined by the number of iterations when performing input data until it reaches the maximum of a parameter value.

  5. Evaluation of a load cell model for dynamic calibration of the rotor systems research aircraft

    NASA Technical Reports Server (NTRS)

    Duval, R. W.; Bahrami, H.; Wellman, B.

    1985-01-01

    The Rotor Systems Research Aircraft uses load cells to isolate the rotor/transmission system from the fuselage. An analytical model of the relationship between applied rotor loads and the resulting load cell measurements is derived by applying a force-and-moment balance to the isolated rotor/transmission system. The model is then used to estimate the applied loads from measured load cell data, as obtained from a ground-based shake test. Using nominal design values for the parameters, the estimation errors, for the case of lateral forcing, were shown to be on the order of the sensor measurement noise in all but the roll axis. An unmodeled external load appears to be the source of the error in this axis.

  6. PRB rail loadings shatter record

    SciTech Connect

    Buchsbaum, L.

    2008-09-15

    Rail transport of coal in the Powder River Basin has expanded, with a record 2,197 trains loaded in a month. Arch Coal's Thunder basin mining complex has expanded by literally bridging the joint line railway. The dry fork mine has also celebrated its safety achievements. 4 photos.

  7. Estimation of Unattenuated Factor Loadings.

    ERIC Educational Resources Information Center

    Woodward, Todd S.; Hunter, Michael A.

    1999-01-01

    Demonstrates that traditional exploratory factor analytic methods, when applied to correlation matrices, cannot be used to estimate unattenuated factor loadings. Presents a mathematical basis for the accurate estimation of such values when the disattenuated correlation matrix or the covariance matrix is used as input. Explains how the equations…

  8. Computer aided design of three-dimensional waveguide loaded cavities

    NASA Astrophysics Data System (ADS)

    Goren, Yehuda; Yu, David U. L.

    1989-02-01

    We have developed two simple methods to calculate the power transport through an external waveguide of a loaded cavity utilizing the RF parameters obtained from the frequency domain codes. In the first method the external power loss through an open waveguide is expressed in terms of equivalent circuit coupling parameters between a closed waveguide and a cavity to which it is connected. As we shall see, this equivalent circuit approach is limited in it applicability only to structures with high loaded Q values, say Q(sub L) less than 200. In the second method, the power flow through an external waveguide is calculated from an analysis of the electromagnetic field components of the standing waves in the closed waveguide-cavity structure. Our models make use of the MAFIA code to obtain values of structural parameters and fields when an external waveguide is abruptly terminated with a metal surface. A typical model consists of an output cavity attached via an iris to a short waveguide section ended with a conducting cap. Our methodologies of calculating the loaded Q(sub L) in terms of the parameters of the closed waveguide-cavity model are described in the following sections. We have obtained reasonable and encouraging results for several loaded cavities whose values of Q(sub L) have been experimentally measured. Of particular interest is the application to low-Q structures such as the relativistic klystron output cavities. The electromagnetic field method yields good agreement with experimental measurements. This method has also been successfully applied to high gradient accelerating structures with slots for damping out higher modes as recently proposed by Palmer.

  9. Finite Element Analysis of a Dynamically Loaded Flat Laminated Plate

    DTIC Science & Technology

    1980-07-01

    Numoer of layers; 12 maximum) NLINC (Number of load increments with time; NLINC21) IPLOT ( Plot parameter, 1 if plot required, 0 if no plot required...when plots are requested; in this case, the line segment cards must define the perimeter of solid continuously. The order of line segment cards...Thickness of layer 2) TH(3) (Thickness of layer 3) etc. up to TH (NUMLA) 68 PLOT TITLE CARD* Format (8A10) Columns 1-80 Title (Title printed under

  10. Study of monitoring load failure of an actuator system

    NASA Astrophysics Data System (ADS)

    Salles, G.; Grellet, G.; Filippetti, F.; Yahoui, H.

    1998-11-01

    This paper addresses the problem of an actuator's load monitoring through a particular fault pattern effects analysis. A load's failure, like a dip of torque superimposed on a constant or sinusoidal steady state load, has an effect on the motor's supply currents. In some cases the high stress and the toxicity of the operating environment of the actuator lead to the inaccessibility of the motor and load set and don't authorize the positioning of sensors. Consequently we use the motor current spectral analysis for the detection of the faults that occur in the load. To propose a global method, this paper presents an approach for the automation of the monitoring and diagnosis processes and studies the capabilities of an easy tool, the spectrogram, to detect the apparition of the fault during the work of the actuator and the signature obtained with different kind of faults and supplies. It also proposes a methodology to determine the parameters of the dip of torque fault. To conclude this study, we show the validity area of the method to other king of failure patterns.

  11. The evaluation of a turbulent loads characterization system

    SciTech Connect

    Kelley, N.D.; McKenna, H.E.

    1996-01-01

    In this paper we discuss an on-line turbulent load characterization system that has been designed to acquire loading spectra from turbines of the same design operating in several different environments and from different turbine designs operating in the same environment. This System simultaneously measures the rainflow-counted alternating and mean loading spectra and the hub-height turbulent mean shearing stress and atmospheric stability associated with the turbulent inflow. We discuss the theory behind the measurement configuration and the results of proof-of-concept testing recently performed at the National Wind Technology Center (NWTC) using a Bergey EXCEL-S 10-kW wind turbine. The on-line approach to characterizing the load spectra and the inflow turbulent scaling parameter produces results that are consistent with other measurements. The on-line approximation of the turbulent shear stress or friction velocity u* also is considered adequate. The system can be used to characterize turbulence loads during turbine deployment in a wide variety of environments. Using the WISPER protocol, we found that a wide-range, variable-speed turbine will accumulate a larger number of stress cycles in the low-cycle, high-amplitude (LCHA) region when compared with a constant speed rotor under similar inflow conditions.

  12. Load Distribution in Congested Scale-Free Networks

    NASA Astrophysics Data System (ADS)

    Zheng, Jian-Feng; Gao, Zi-You; Fu, Bai-Bai

    In this work, we study the effects of scale-free topology and congestion on load distribution. Congestion effect can be described by link cost functions, which map link flows into travel times. Two different kinds of link's practical capacity (it is similar to link's capacity for transport) which is a parameter in link cost functions, i.e., uniform case and nonuniform case, are investigated. After introducing the effect of congestion, load distribution is typically discussed in Barábasi-Albert and Goh scale-free networks. In the uniform case, for Barábasi-Albert scale-free networks, we recover a power-law behavior for load distribution with a larger exponent, as compared with the distribution of betweenness centrality; for Goh scale-free networks, we also recover a power-law behavior and its exponent approaches to the exponent of degree distribution. While in the nonuniform case, the power-law behavior for load distribution may not always be conserved in both Barábasi-Albert and Goh scale-free networks. That is to say, different kinds of load distributions are obtained under different conditions. It may shed some light to study traffic dynamics on scale-free networks.

  13. Progressive failure of large deformation composites under dynamic tensile loading

    NASA Astrophysics Data System (ADS)

    Xing, Liqun

    The applications of polymer based composite materials in structural components under dynamic loading have increased dramatically. The accurate understanding and modeling of the material mechanical behavior is the basis for the composite structure design and analysis. This research was designed to investigate the progressive failure nature of woven polymer-based composites under dynamic tensile loading conditions. A plain-woven E-glass/vinyl ester composite was selected and a generalized anisotropic material characterization procedure was developed. Off-axial tensile dynamic loading experiments with different strain rates and temperature was conducted. A nonlinear and rate dependent constitutive model used for the polymer-based composites under tensile dynamic tensile loading was constructed. The comparison shows a good match with testing data and a good prediction of stress to failure values. A hybrid method that combined the classical laminate theory with material microstructure analysis was presented to model the large strain to failure phenomenon. A single material parameter failure criteria based on Monkman-Grant concept was built to represent the materials anisotropic and rate dependency natural for tensile loading. And the strength concept based on the material constitution relationship and failure criteria was established to for structure analyses.

  14. Modelling of a chaotic load of wind turbines drivetrain

    NASA Astrophysics Data System (ADS)

    Bielecki, Andrzej; Barszcz, Tomasz; Wójcik, Mateusz

    2015-03-01

    The purpose of this paper is to present a model of the load of the wind turbine gears for simulation of real, varying operational conditions for modelling of wind turbine vibration. The characteristics of the wind, which generates chaotically varying loads on the drivetrain components generating load in teeth and bearings of gears during torque transfer, are discussed. A generator of variable load of wind turbines drivetrain is proposed. Firstly, the module for generation of wind speed is designed. It is based on the approach in which the wind speed was considered as a time series approximated by the Weierstrass function. Secondly, the rotational speed of the main shaft is proposed as a function of the wind speed value. The function depends on a few parameters that are fitted by using a genetic algorithm. Finally, the model of torque of the main shaft is introduced. This model has been created by using a multi-layer artificial neural network. The results show that the proposed approach yields a very good fit for the experimental data. The fit brings about the proper reproducing of all the aspects of the load that are crucial for causing fatigue and, as a consequence, damaging of gears of the wind turbines.

  15. Modified multi-load method for nonlinear source characterisation

    NASA Astrophysics Data System (ADS)

    Rämmal, Hans; Bodén, Hans

    2007-02-01

    Linear frequency domain prediction codes are useful for calculation of low-frequency sound transmission in duct and pipe systems. To calculate insertion loss of mufflers or the level of radiated sound information about the acoustic source is needed. The source model used in the low-frequency plane wave range is the linear time invariant one-port model. The acoustic source data is usually obtained from experimental tests where multi-load methods and especially the two-load method are most commonly used. The exhaust pulsations of for example an IC-engine are of high level, and the engine is not a perfectly linear and time invariant source. It is therefore of interest to develop source models and experimental techniques that try to take this nonlinearity into account. In this paper a modified version of the two-load method to improve the characterisation of nonlinear acoustic one-port sources has been developed and tested. Simulation results as well as experimental data from various source configurations for a modified compressor and experimental data from 6-cylinder turbocharged truck diesel engine were used to validate the method. The influence of parameters controlling the linearity of the system was investigated. The time-variance of the source model was varied and the accuracy of source characterisation results using the two-load method and the modified two-load method was evaluated.

  16. Monitoring Training Loads: The Past, the Present, and the Future.

    PubMed

    Foster, Carl; Rodriguez-Marroyo, Jose A; de Koning, Jos J

    2017-03-02

    Training monitoring is about keeping track of what athletes accomplish in training, for the purpose of improving the interaction between coach and athlete. Over history there have been several basic schemes of training monitoring. In the earliest days training monitoring was about observing the athlete during standard workouts. However, difficulty in standardizing the conditions of training made this process unreliable. With the advent of interval training, monitoring became more systematic. However, imprecision in the measurement of HR evolved interval training toward index workouts, where the main monitored parameter was average time required to complete index workouts. These measures of training load focused on the external training load, what the athlete could actually do. With the advent of interest from the scientific community, the development of the concept of metabolic thresholds, and the possibility of trackside measurement of HR, lactate, VO2 and power output, there was greater interest in the internal training load, allowing better titration of training loads in athletes of differing ability. These methods show much promise, but often require laboratory testing for calibration, and tend to produce too much information, in too slow of a time frame, to be optimally useful to coaches. The advent of the TRIMP concept by Banister suggested a strategy to combine intensity and duration elements of training into a single index concept, training LOAD. Although the original TRIMP concept was mathematically complex, the development of the Session RPE and similar low tech methods has demonstrated a way to evaluate training LOAD, along with derived variables, in a simple, responsive way. Recently, there has been interest in using wearable sensors to provide high resolution data of the external training load. These methods are promising, but problems relative to information overload and turn-around time to coaches remain to be solved.

  17. Coupling between meteorological factors and ambient aerosol load

    NASA Astrophysics Data System (ADS)

    Tandon, Ankit; Yadav, Sudesh; Attri, Arun K.

    2010-03-01

    The coarser (CPM) and respirable (RPM) fractions of aerosol loads collected in a time sequence, during the onset of winter season in Delhi region, were subjected to Principal Component Analysis (15 elemental variables, 39 samples); the absolute mass contributed by each identified source to the CPM and RPM was quantified by using Absolute Principal Component Score (APCS) and Positive Matrix Factorization (PMF) method. Interestingly, the mass contributed by the local crustal source (material) to both fractions manifested undulating periodic behavior, a dominating harmonic corresponding to 24-h period was detected by using Discrete Fourier Transform (DFT). The corresponding harmonics, of varying strengths, were also detected in the recorded meteorological factors: Planetary Boundary Layer (PBL), Surface Level Temperature (T), Surface Level Relative Humidity (RH) and Wind Speed (WS). The analysis of the respective harmonic strength within the CPM, RPM, and meteorological factors suggested that the undulation observed in both size fractions of aerosol load from the local crust was affected by the meteorological factors. The large proportion of undulating loads (CPM and RPM), explained by the dominating harmonic, was fully accounted for by the empirical relation involving the discrete coupling parameters, and the recorded meteorological factors: PBL, T, RH and WS. The analysis suggests that the magnitude and the direction ('positive' load increase and 'negative' the reverse) of coupled meteorological factors'(s) effect on ambient CPM, RPM load is determined by the phase difference between the harmonic explaining the aerosol fraction's load and the corresponding harmonic present in the respective meteorological factor. The absolute mass contributions arising from the identified sources (APCS and PMF) allowed us to calculate the baseline ambient concentrations of undulating CPM and RPM loads, in the region of this study, affected by meteorological factors only.

  18. Nonlinear Bulging Factors for Longitudinal and Circumferential Cracks in Cylindrical Shells Subjected to Combined Loads

    NASA Technical Reports Server (NTRS)

    Young, Richard D.; Rose, Cheryl A.; Starnes, James H., Jr.

    2000-01-01

    Results of a geometrically nonlinear finite element parametric study to determine curvature correction factors or bulging factors that account for increased crack-tip stresses due to curvature for longitudinal and circumferential cracks in unstiffened cylindrical shells subjected to combined loads are presented. Nondimensional parameters varied in the study include the shell curvature parameter, l , which is a function of the shell radius, the shell wall thickness, and the crack length; a pressure loading parameter, h , which is a function of the shell geometry, material properties and the applied internal pressure; and a biaxial loading parameter, c , which is the ratio of the farfield axial stress to the farfield circumferential stress. The major results are presented in the form of contour plots of the bulging factor as a function of these three nondimensional parameters. These plots identify the ranges of the shell curvature and loading parameters for which the effects of geometric nonlinearity are significant, and show the effect of the biaxial loads on the value of the bulging factor. Simple empirical expressions for the bulging factor are then derived from the numerical results and are shown to predict accurately the nonlinear response of shells with longitudinal and circumferential cracks.

  19. A variable parameter parametric snake method

    NASA Astrophysics Data System (ADS)

    Marouf, A.; Houacine, A.

    2015-12-01

    In this paper, we introduce a new approach to parametric snake method by using variable snake parameters. Adopting fixed parameter values for all points of the snake, as usual, constitutes by itself a limitation that leads to poor performances in terms of convergence and tracking properties. A more adapted choice should be the one that allows selection depending on the image region properties as on the contour shape and position. However, such variability is not an easy task in general and a precise method need to be defined to assure contour point dependent tuning at iterations. We were particularly interested in applying this idea to the recently presented parametric method [1]. In the work mentioned, an attraction term is used to improve the convergence of the standard parametric snake without a significant increase in computational load. We show here, that improved performances can ensue from applying variable parameter concepts. For this purpose, the method is first analyzed and then a procedure is developed to assure an automatic variable parameter tuning. The interest of our approach is illustrated through object segmentation results.

  20. Interactions Between Modality of Working Memory Load and Perceptual Load in Distractor Processing.

    PubMed

    Koshino, Hideya; Olid, Pilar

    2015-01-01

    The present study investigated interactions between working memory load and perceptual load. The load theory (Lavie, Hirst, de Fockert, & Viding, 2004 ) claims that perceptual load decreases distractor interference, whereas working memory load increases interference. However, recent studies showed that effects of working memory might depend on the relationship between modalities of working memory and task stimuli. Here, we examined whether the relationship between working memory load and perceptual load would remain the same across modalities. The results of Experiment 1 showed that verbal working memory load did not affect a compatibility effect for low perceptual load, whereas it increased the compatibility effect for high perceptual load. In Experiment 2, the compatibility effect remained the same regardless of visual working memory load. These results suggest that the effects of working memory load and perceptual load depend on the relationship between the modalities of working memory and stimuli.

  1. Influence of Operating Parameters on Running-in Wear of EN-31 Steel

    NASA Astrophysics Data System (ADS)

    Hanief, M.; Wani, M. F.

    2016-10-01

    In this paper, effect of operating parameters (temperature, surface roughness and load) was investigated to determine the influence of each parameter on the wear rate. A mathematical model was developed to establish a functional relationship between the running-in wear rate and the operating parameters. The proposed model being non-linear, it was linearized by logarithmic transformation and the optimal values of model parameters were obtained by least square method. It was found that the surface roughness has significant effect on wear rate followed by load and temperature. The adequacy of the model was estimated by statistical methods (coefficient of determination (R2) and mean absolute percentage error (MAPE)) .

  2. End Effects and Load Diffusion in Composite Structures

    NASA Technical Reports Server (NTRS)

    Horgan, Cornelius O.; Ambur, D. (Technical Monitor); Nemeth, M. P. (Technical Monitor)

    2002-01-01

    The research carried out here builds on our previous NASA supported research on the general topic of edge effects and load diffusion in composite structures. Further fundamental solid mechanics studies were carried out to provide a basis for assessing the complicated modeling necessary for large scale structures used by NASA. An understanding of the fundamental mechanisms of load diffusion in composite subcomponents is essential in developing primary composite structures. Specific problems recently considered were focussed on end effects in sandwich structures and for functionally graded materials. Both linear and nonlinear (geometric and material) problems have been addressed. Our goal is the development of readily applicable design formulas for the decay lengths in terms of non-dimensional material and geometric parameters. Analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and assessing results from finite element analyses. The decay behavior of stresses and other field quantities provides a significant aid towards this process. The analysis is also amenable to parameter study with a large parameter space and should be useful in structural tailoring studies.

  3. 14 CFR 25.511 - Ground load: unsymmetrical loads on multiple-wheel units.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Loads § 25.511 Ground load: unsymmetrical loads on multiple-wheel units. (a) General. Multiple-wheel... gear unit using four or more wheels per unit, must be considered; and (2) The ground reactions must be... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ground load: unsymmetrical loads...

  4. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ethylene oxide: Loading and off loading. 154.1730... Operating Requirements § 154.1730 Ethylene oxide: Loading and off loading. (a) The master shall ensure that before ethylene oxide is loaded into a cargo tank: (1) The tank is thoroughly clean, dry, and free...

  5. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ethylene oxide: Loading and off loading. 154.1730... Operating Requirements § 154.1730 Ethylene oxide: Loading and off loading. (a) The master shall ensure that before ethylene oxide is loaded into a cargo tank: (1) The tank is thoroughly clean, dry, and free...

  6. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ethylene oxide: Loading and off loading. 154.1730... Operating Requirements § 154.1730 Ethylene oxide: Loading and off loading. (a) The master shall ensure that before ethylene oxide is loaded into a cargo tank: (1) The tank is thoroughly clean, dry, and free...

  7. Loads Model Development and Analysis for the F/A-18 Active Aeroelastic Wing Airplane

    NASA Technical Reports Server (NTRS)

    Allen, Michael J.; Lizotte, Andrew M.; Dibley, Ryan P.; Clarke, Robert

    2005-01-01

    The Active Aeroelastic Wing airplane was successfully flight-tested in March 2005. During phase 1 of the two-phase program, an onboard excitation system provided independent control surface movements that were used to develop a loads model for the wing structure and wing control surfaces. The resulting loads model, which was used to develop the control laws for phase 2, is described. The loads model was developed from flight data through the use of a multiple linear regression technique. The loads model input consisted of aircraft states and control surface positions, in addition to nonlinear inputs that were calculated from flight-measured parameters. The loads model output for each wing consisted of wing-root bending moment and torque, wing-fold bending moment and torque, inboard and outboard leading-edge flap hinge moment, trailing-edge flap hinge moment, and aileron hinge moment. The development of the Active Aeroelastic Wing loads model is described, and the ability of the model to predict loads during phase 2 research maneuvers is demonstrated. Results show a good match to phase 2 flight data for all loads except inboard and outboard leading-edge flap hinge moments at certain flight conditions. The average load prediction errors for all loads at all flight conditions are 9.1 percent for maximum stick-deflection rolls, 4.4 percent for 5-g windup turns, and 7.7 percent for 4-g rolling pullouts.

  8. CELSS engineering parameters

    NASA Technical Reports Server (NTRS)

    Drysdale, Alan; Sager, John; Wheeler, Ray; Fortson, Russ; Chetirkin, Peter

    1993-01-01

    The most important Controlled Ecological Life Support System (CELSS) engineering parameters are, in order of decreasing importance, manpower, mass, and energy. The plant component is a significant contributor to the total system equivalent mass. In this report, a generic plant component is described and the relative equivalent mass and productivity are derived for a number of instances taken from the KSC CELSS Breadboard Project data and literature. Typical specific productivities (edible biomass produced over 10 years divided by system equivalent mass) for closed systems are of the order of 0.2.

  9. NICMOS Defocus parameter test

    NASA Astrophysics Data System (ADS)

    Dashevsky, Ilana

    2007-07-01

    This proposal tests the new NICMOS non-nominal focus positions, which are implemented in the front-end systems and are specified in the Phase II using the CAMERA-FOCUS=DEFOCUS Optional Parameter. The targets from Proposals 9832 and 11063 are used in this Proposal. The GO Proposal 9832 is an example of how GOs may use the new non-nominal focus implementation for detector 3. Proposal 11063 is the NICMOS focus monitor, which will be used to verify the non-nominal focus for all 3 detectors.

  10. Force response of the fingertip pulp to repeated compression--effects of loading rate, loading angle and anthropometry.

    PubMed

    Serina, E R; Mote, C D; Rempel, D

    1997-10-01

    Repeated loading of the fingertips has been postulated to contribute to tendon and nerve disorders at the wrist during activities associated with prolonged fingertip loading such as typing. To fully understand the pathomechanics of these soft tissue disorders, the role of the fingertip pulp in attenuating the applied dynamic forces must be known. An experiment was conducted to characterize the response of the in vivo fingertip pulp under repeated, dynamic, compressive loadings, to identify factors that influence pulp dynamics, and to better understand the force modulation by the pulp. Twenty subjects tapped repeatedly on a flat plate with their left index finger, while the contact force and pulp displacement were measured simultaneously. Tapping trials were conducted at three fingertip contact angles from the horizontal plane (0 degree, 45 degrees, and 90 degrees) and five tapping rates (0.25, 0.5, 1, 2, and 3 Hz). The fingertip pulp responds as a viscoelastic material, exhibiting rate-dependence, hysteresis, and a nonlinear force-displacement relationship. The pulp was relatively compliant at forces less than 1 N, but stiffened rapidly with displacement at higher forces for all loading conditions. This suggests that high-frequency forces of a small magnitude (< 1 N) are attenuated by the nonlinearly stiffening pulp while these forces of larger magnitude are transmitted to the bone. Pulp response was significantly influenced by the angle of loading. Fingertip dimensions, gender, and subject age had little to no influence on pulp parameters.

  11. Efficient load measurements using singular value decomposition

    NASA Technical Reports Server (NTRS)

    Yao, Kung; Balakrishnan, A. V.

    1988-01-01

    Various basic research was performed on efficient load measurement estimation techniques for aircraft structure analysis. An overview is presented of the load measurement problem. Two basic equivalent approaches to load measurement evaluations were considered. Under approach 1, the load values are modeled as depending linearly on the measured values. Under approach 2, the measured values depend linearly on the load values. By using the modern Singular Value Decomposition method, it was shown that under all conditions of the number of loads and number of gages, approach 1 is equivalent to approach 2. By using the conventional normal equation (linear regression) approach, approach 1 is only valid when the number of loads is equal to or greater than the number of gages, while approach 2 is the reverse. Furthermore, except for the case of the number of loads equals the number of gages, the load prediction formulas under the two approaches are not equivalent.

  12. Fault detection of planetary gearboxes using new diagnostic parameters

    NASA Astrophysics Data System (ADS)

    Lei, Yaguo; Kong, Detong; Lin, Jing; Zuo, Ming J.

    2012-05-01

    Planetary gearboxes are commonly used in modern industry because of their large transmission ratio and strong load-bearing capacity. They generally work under heavy load and tough working environment and therefore their key components including sun gear, planet gears, ring gear, etc are subject to severe pitting and fatigue crack. Planetary gearboxes significantly differ from fixed-axis gearboxes and exhibit unique behavior, which invalidates the use of the diagnostic parameters developed and suitable for fixed-axis gearboxes. Therefore, there is a need to develop parameters specifically for detecting and diagnosing faults of planetary gearboxes. In this study, two diagnostic parameters are proposed based on the examination of the vibration characteristics of planetary gearboxes in both time and frequency domains. One is the root mean square of the filtered signal (FRMS) and the other is the normalized summation of positive amplitudes of the difference spectrum between the unknown signal and the healthy signal (NSDS). To test the proposed diagnostic parameters, we conducted experiments on a planetary gearbox test rig with sun gear faults including a cracked tooth and a pitted tooth. The vibration signals were measured under different motor speeds. The proposed parameters are compared with the existing parameters reported in the literature. The comparison results show the proposed diagnostic parameters perform better than others.

  13. Sensitivity of footbridge vibrations to stochastic walking parameters

    NASA Astrophysics Data System (ADS)

    Pedersen, Lars; Frier, Christian

    2010-06-01

    Some footbridges are so slender that pedestrian traffic can cause excessive vibrations and serviceability problems. Design guidelines outline procedures for vibration serviceability checks, but it is noticeable that they rely on the assumption that the action is deterministic, although in fact it is stochastic as different pedestrians generate different dynamic forces. For serviceability checks of footbridge designs it would seem reasonable to consider modelling the stochastic nature of the main parameters describing the excitation, such as for instance the load amplitude and the step frequency of the pedestrian. A stochastic modelling approach is adopted for this paper and it facilitates quantifying the probability of exceeding various vibration levels, which is useful in a discussion of serviceability of a footbridge design. However, estimates of statistical distributions of footbridge vibration levels to walking loads might be influenced by the models assumed for the parameters of the load model (the walking parameters). The paper explores how sensitive estimates of the statistical distribution of vertical footbridge response are to various stochastic assumptions for the walking parameters. The basis for the study is a literature review identifying different suggestions as to how the stochastic nature of these parameters may be modelled, and a parameter study examines how the different models influence estimates of the statistical distribution of footbridge vibrations. By neglecting scatter in some of the walking parameters, the significance of modelling the various walking parameters stochastically rather than deterministically is also investigated providing insight into which modelling efforts need to be made for arriving at reliable estimates of statistical distributions of footbridge vibrations. The studies for the paper are based on numerical simulations of footbridge responses and on the use of Monte Carlo simulations for modelling the stochastic nature of

  14. Walking with a Backpack using Load Distribution and Dynamic Load Compensation Reduces Metabolic Cost and Adaptations to Loads.

    PubMed

    Park, Joon-Hyuk; Stegall, Paul; Zhang, Haohan; Agrawal, Sunil

    2016-11-09

    In this study, we showed a way of reducing the metabolic cost of walking with a backpack using load distribution and dynamic load compensation, provided by a wearable upper body device. This device distributes the backpack load between the shoulders and the pelvis, senses the vertical motion of the pelvis, and provides gait synchronized compensatory forces to reduce the dynamic loads from a backpack. It was hypothesized that by reducing dynamic loads from a backpack during load carriage, the users gait and postural adaptation, muscular effort and metabolic cost would be reduced. This hypothesis was supported by biomechanical and physiological measurements on a group of young healthy subjects, as they walked on a treadmill under 4 different conditions: unloaded; with a backpack, loaded with 25% of their body weight, supported on the shoulders; with the same load distributed between the shoulders and the pelvis; and with dynamic load compensation in addition to load distribution. The results showed reductions in gait and postural adaptations, muscle activity, vertical and braking ground reaction forces, and metabolic cost while carrying the same backpack load with the device. We conclude that the device can potentially reduce the risk of musculoskeletal injuries and muscle fatigue associated with carrying heavy backpack loads while reducing the metabolic cost of loaded walking.

  15. Spinning Reserve From Responsive Loads

    SciTech Connect

    Kirby, B.J.

    2003-04-08

    Responsive load is the most underutilized reliability resource available to the power system today. It is currently not used at all to provide spinning reserve. Historically there were good reasons for this, but recent technological advances in communications and controls have provided new capabilities and eliminated many of the old obstacles. North American Electric Reliability Council (NERC), Federal Energy Regulatory Commission (FERC), Northeast Power Coordinating Council (NPCC), New York State Reliability Council (NYSRC), and New York Independent System Operator (NYISO) rules are beginning to recognize these changes and are starting to encourage responsive load provision of reliability services. The Carrier ComfortChoice responsive thermostats provide an example of these technological advances. This is a technology aimed at reducing summer peak demand through central control of residential and small commercial air-conditioning loads. It is being utilized by Long Island Power Authority (LIPA), Consolidated Edison (ConEd), Southern California Edison (SCE), and San Diego Gas and Electric (SDG&E). The technology is capable of delivering even greater response in the faster spinning reserve time frame (while still providing peak reduction). Analysis of demand reduction testing results from LIPA during the summer of 2002 provides evidence to back up this claim. It also demonstrates that loads are different from generators and that the conventional wisdom, which advocates for starting with large loads as better ancillary service providers, is flawed. The tempting approach of incrementally adapting ancillary service requirements, which were established when generators were the only available resources, will not work. While it is easier for most generators to provide replacement power and non-spinning reserve (the slower response services) than it is to supply spinning reserve (the fastest service), the opposite is true for many loads. Also, there is more financial

  16. Thermal loading of natural streams

    USGS Publications Warehouse

    Jackman, Alan P.; Yotsukura, Nobuhiro

    1977-01-01

    The impact of thermal loading on the temperature regime of natural streams is investigated by mathematical models, which describe both transport (convection-diffusion) and decay (surface dissipation) of waste heat over 1-hour or shorter time intervals. The models are derived from the principle of conservation of thermal energy for application to one- and two-dimensional spaces. The basic concept in these models is to separate water temperature into two parts, (1) excess temperature due to thermal loading and (2) natural (ambient) temperature. This separation allows excess temperature to be calculated from the models without incoming radiation data. Natural temperature may either be measured in prototypes or calculated from the model. If use is made of the model, however, incoming radiation is required as input data. Comparison of observed and calculated temperatures in seven natural streams shows that the models are capable of predicting transient temperature regimes satisfactorily in most cases. (Woodard-USGS)

  17. Auditory perceptual load: A review.

    PubMed

    Murphy, Sandra; Spence, Charles; Dalton, Polly

    2017-02-08

    Selective attention is a crucial mechanism in everyday life, allowing us to focus on a portion of incoming sensory information at the expense of other less relevant stimuli. The circumstances under which irrelevant stimuli are successfully ignored have been a topic of scientific interest for several decades now. Over the last 20 years, the perceptual load theory (e.g. Lavie, 1995) has provided one robust framework for understanding these effects within the visual modality. The suggestion is that successful selection depends on the perceptual demands imposed by the task-relevant information. However, less research has addressed the question of whether the same principles hold in audition and, to date, the existing literature provides a mixed picture. Here, we review the evidence for and against the applicability of perceptual load theory in hearing, concluding that this question still awaits resolution.

  18. On Combinations of Random Loads

    DTIC Science & Technology

    1980-01-01

    NPS55-80-006 NAVAL POSTGRADUATE SCHOOL NM ’Monterey, California 00 •2• • TD -E E C AN : JUN 16 1980 i ON COMBINATIONS OF RANDOM LOADS by D. P. Gaver...of MKn is close to that of Mn for K large. PROPOSITION (3.3). Let F and G be as in (3.5), and u be such that (un)-c L(un) n as n ÷ (3.6) Then lim HKn

  19. Efficient Solutions in Load Planning

    DTIC Science & Technology

    2004-04-01

    The current load planning capability is achieved through a conference and the use of a trim and stability tool. In order to make this process more...mathematical modelling of combustion processes , especially concentrating on spontaneous ignition. Jane works in the Amphibious and Mine Warfare...directives, (b) amphibious planning process and (c) mounting, embarkation and landing planning. It is with stage (c) that this paper is concerned. "Plans

  20. Structural dynamics payload loads estimates

    NASA Technical Reports Server (NTRS)

    Engels, R. C.

    1981-01-01

    The development of a full scale payload integration method which reduces the cost of a load cycle and is capable of land long very large systems is discussed. The method solves the coupled booster/payload system equations and does not involve additional approximations as compared to the standard transient analysis. The method is cost effective and directly applicable to the shuttle payload design case.

  1. Display Parameters and Requirements

    NASA Astrophysics Data System (ADS)

    Bahadur, Birendra

    The following sections are included: * INTRODUCTION * HUMAN FACTORS * Anthropometry * Sensory * Cognitive * Discussions * THE HUMAN VISUAL SYSTEM - CAPABILITIES AND LIMITATIONS * Cornea * Pupil and Iris * Lens * Vitreous Humor * Retina * RODS - NIGHT VISION * CONES - DAY VISION * RODS AND CONES - TWILIGHT VISION * VISUAL PIGMENTS * MACULA * BLOOD * CHOROID COAT * Visual Signal Processing * Pathways to the Brain * Spatial Vision * Temporal Vision * Colour Vision * Colour Blindness * DICHROMATISM * Protanopia * Deuteranopia * Tritanopia * ANOMALOUS TRICHROMATISM * Protanomaly * Deuteranomaly * Tritanomaly * CONE MONOCHROMATISM * ROD MONOCHROMATISM * Using Colour Effectively * COLOUR MIXTURES AND THE CHROMATICITY DIAGRAM * Colour Matching Functions and Chromaticity Co-ordinates * CIE 1931 Colour Space * CIE PRIMARIES * CIE COLOUR MATCHING FUNCTIONS AND CHROMATICITY CO-ORDINATES * METHODS FOR DETERMINING TRISTIMULUS VALUES AND COLOUR CO-ORDINATES * Spectral Power Distribution Method * Filter Method * CIE 1931 CHROMATICITY DIAGRAM * ADDITIVE COLOUR MIXTURE * CIE 1976 Chromaticity Diagram * CIE Uniform Colour Spaces and Colour Difference Formulae * CIELUV OR L*u*v* * CIELAB OR L*a*b* * CIE COLOUR DIFFERENCE FORMULAE * Colour Temperature and CIE Standard Illuminants and source * RADIOMETRIC AND PHOTOMETRIC QUANTITIES * Photopic (Vλ and Scotopic (Vλ') Luminous Efficiency Function * Photometric and Radiometric Flux * Luminous and Radiant Intensities * Incidence: Illuminance and Irradiance * Exitance or Emittance (M) * Luminance and Radiance * ERGONOMIC REQUIREMENTS OF DISPLAYS * ELECTRO-OPTICAL PARAMETERS AND REQUIREMENTS * Contrast and Contrast Ratio * Luminance and Brightness * Colour Contrast and Chromaticity * Glare * Other Aspects of Legibility * SHAPE AND SIZE OF CHARACTERS * DEFECTS AND BLEMISHES * FLICKER AND DISTORTION * ANGLE OF VIEW * Switching Speed * Threshold and Threshold Characteristic * Measurement Techniques For Electro-optical Parameters * RADIOMETRIC

  2. Control Allocation with Load Balancing

    NASA Technical Reports Server (NTRS)

    Bodson, Marc; Frost, Susan A.

    2009-01-01

    Next generation aircraft with a large number of actuators will require advanced control allocation methods to compute the actuator commands needed to follow desired trajectories while respecting system constraints. Previously, algorithms were proposed to minimize the l1 or l2 norms of the tracking error and of the actuator deflections. The paper discusses the alternative choice of the l(infinity) norm, or sup norm. Minimization of the control effort translates into the minimization of the maximum actuator deflection (min-max optimization). The paper shows how the problem can be solved effectively by converting it into a linear program and solving it using a simplex algorithm. Properties of the algorithm are also investigated through examples. In particular, the min-max criterion results in a type of load balancing, where the load is th desired command and the algorithm balances this load among various actuators. The solution using the l(infinity) norm also results in better robustness to failures and to lower sensitivity to nonlinearities in illustrative examples.

  3. Inducer Hydrodynamic Load Measurement Devices

    NASA Technical Reports Server (NTRS)

    Skelley, Stephen E.; Zoladz, Thomas F.

    2002-01-01

    Marshall Space Flight Center (MSFC) has demonstrated two measurement devices for sensing and resolving the hydrodynamic loads on fluid machinery. The first - a derivative of the six component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This "rotating balance" was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining both the amplitude and frequency content associated with operating in various cavitation modes. The second device - a high frequency response pressure transducer surface mounted on a rotating component - was merely an extension of existing technology for application in water. MSFC has recently completed experimental evaluations of both the rotating balance and surface-mount transducers in a water test loop. The measurement bandwidth of the rotating balance was severely limited by the relative flexibility of the device itself, resulting in an unexpectedly low structural bending mode and invalidating the higher frequency response data. Despite these limitations, measurements confirmed that the integrated loads on the four-bladed inducer respond to both cavitation intensity and cavitation phenomena. Likewise, the surface-mount pressure transducers were subjected to a range of temperatures and flow conditions in a non-rotating environment to record bias shifts and transfer functions between the transducers and a reference device. The pressure transducer static performance was within manufacturer's specifications and dynamic response accurately followed that of the reference.

  4. Inducer Hydrodynamic Load Measurement Devices

    NASA Technical Reports Server (NTRS)

    Skelley, Stephen E.; Zoladz, Thomas F.; Turner, Jim (Technical Monitor)

    2002-01-01

    Marshall Space Flight Center (MSFC) has demonstrated two measurement devices for sensing and resolving the hydrodynamic loads on fluid machinery. The first - a derivative of the six-component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This rotating balance was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining both the amplitude and frequency content associated with operating in various cavitation modes. The second device - a high frequency response pressure transducer surface mounted on a rotating component - was merely an extension of existing technology for application in water. MSFC has recently completed experimental evaluations of both the rotating balance and surface-mount transducers in a water test loop. The measurement bandwidth of the rotating balance was severely limited by the relative flexibility of the device itself, resulting in an unexpectedly low structural bending mode and invalidating the higher-frequency response data. Despite these limitations, measurements confirmed that the integrated loads on the four-bladed inducer respond to both cavitation intensity and cavitation phenomena. Likewise, the surface-mount pressure transducers were subjected to a range of temperatures and flow conditions in a non-rotating environment to record bias shifts and transfer functions between the transducers and a reference device. The pressure transducer static performance was within manufacturer's specifications and dynamic response accurately followed that of the reference.

  5. Passive detection of vehicle loading

    NASA Astrophysics Data System (ADS)

    McKay, Troy R.; Salvaggio, Carl; Faulring, Jason W.; Salvaggio, Philip S.; McKeown, Donald M.; Garrett, Alfred J.; Coleman, David H.; Koffman, Larry D.

    2012-01-01

    The Digital Imaging and Remote Sensing Laboratory (DIRS) at the Rochester Institute of Technology, along with the Savannah River National Laboratory is investigating passive methods to quantify vehicle loading. The research described in this paper investigates multiple vehicle indicators including brake temperature, tire temperature, engine temperature, acceleration and deceleration rates, engine acoustics, suspension response, tire deformation and vibrational response. Our investigation into these variables includes building and implementing a sensing system for data collection as well as multiple full-scale vehicle tests. The sensing system includes; infrared video cameras, triaxial accelerometers, microphones, video cameras and thermocouples. The full scale testing includes both a medium size dump truck and a tractor-trailer truck on closed courses with loads spanning the full range of the vehicle's capacity. Statistical analysis of the collected data is used to determine the effectiveness of each of the indicators for characterizing the weight of a vehicle. The final sensing system will monitor multiple load indicators and combine the results to achieve a more accurate measurement than any of the indicators could provide alone.

  6. PASSIVE DETECTION OF VEHICLE LOADING

    SciTech Connect

    Garrett, A.

    2012-01-03

    The Digital Imaging and Remote Sensing Laboratory (DIRS) at the Rochester Institute of Technology, along with the Savannah River National Laboratory is investigating passive methods to quantify vehicle loading. The research described in this paper investigates multiple vehicle indicators including brake temperature, tire temperature, engine temperature, acceleration and deceleration rates, engine acoustics, suspension response, tire deformation and vibrational response. Our investigation into these variables includes building and implementing a sensing system for data collection as well as multiple full-scale vehicle tests. The sensing system includes; infrared video cameras, triaxial accelerometers, microphones, video cameras and thermocouples. The full scale testing includes both a medium size dump truck and a tractor-trailer truck on closed courses with loads spanning the full range of the vehicle's capacity. Statistical analysis of the collected data is used to determine the effectiveness of each of the indicators for characterizing the weight of a vehicle. The final sensing system will monitor multiple load indicators and combine the results to achieve a more accurate measurement than any of the indicators could provide alone.

  7. Loss parameter calculations

    SciTech Connect

    Cook, J.M.

    1995-07-01

    Sands and Rees propose an electronic bench measurement of the impulse energy loss of a stored particle bunch to vacuum-chamber components. The components act as the outer conductor of a coaxial line with a thin wire as center conductor. Short pulses are then transmitted through this coaxial system to simulate relativistic particle bunches. Their proposal has since been implemented by several investigators and has become a well-known technique. They derive a first-order approximation to the loss parameter {kappa} for use in these measurements. The purpose of this note is to point out that exact expression for {kappa} is as simple as its first-order approximation and to recommend its use even when {kappa} is small.

  8. Precision cosmological parameter estimation

    NASA Astrophysics Data System (ADS)

    Fendt, William Ashton, Jr.

    2009-09-01

    methods. These techniques will help in the understanding of new physics contained in current and future data sets as well as benefit the research efforts of the cosmology community. Our idea is to shift the computationally intensive pieces of the parameter estimation framework to a parallel training step. We then provide a machine learning code that uses this training set to learn the relationship between the underlying cosmological parameters and the function we wish to compute. This code is very accurate and simple to evaluate. It can provide incredible speed- ups of parameter estimation codes. For some applications this provides the convenience of obtaining results faster, while in other cases this allows the use of codes that would be impossible to apply in the brute force setting. In this thesis we provide several examples where our method allows more accurate computation of functions important for data analysis than is currently possible. As the techniques developed in this work are very general, there are no doubt a wide array of applications both inside and outside of cosmology. We have already seen this interest as other scientists have presented ideas for using our algorithm to improve their computational work, indicating its importance as modern experiments push forward. In fact, our algorithm will play an important role in the parameter analysis of Planck, the next generation CMB space mission.

  9. Beam loading in magnicon deflection cavities

    SciTech Connect

    Hafizi, B.; Gold, S.H.

    1997-02-01

    The radio frequency (RF) source for the next linear collider (NLC) is required to generate a power of 1/2--1 GW per tube in a 200-ns pulse, or 100--200 J of energy in a pulse of up to a few {micro}s in duration, at a frequency of 10--20 GHz. A variety of RF sources are under investigation at the present time aimed at fulfilling the needs of the NLC. These include the X-band klystron, Gyroklystron, traveling-wave tube, harmonic convertor, chopper-driven traveling-wave tube, and magnicon. Here, analysis of the beam-deflection cavity interaction in a magnicon is presented and compared with experiment. For a driven cavity a dispersion relation is obtained wherein the interaction modifies the cold-cavity factor and the resonance frequency. In terms of a lumped-parameter equivalent circuit the interaction corresponds to a complex-values beam admittance Y{sub b} in parallel with the cavity admittance. The response of the gain cavities is modified by the same admittance. In a magnicon, Y{sub b} is a sensitive function of the solenoidal focusing magnetic field B{sub 0}, thus providing a convenient means of adjusting the cavity properties in experiments. When the relativistic gyrofrequency is twice the drive frequency, ImY{sub b} = 0 and the beam does not load the cavity. Analytical expressions of the variation of the detuning, instantaneous bandwidth (i.e., loaded quality factor) and gain with B{sub 0} are derived. Simulation results are presented to verify the linear analysis with ideal beams and to illustrate the modifications due to finite beam emittance. Results of the magnicon experiment at the Naval Research Laboratory are examined in the light of the analysis.

  10. UK catchment nutrient loads 1993-2003, a new approach using harmonised monitoring scheme data: temporal changes, geographical distribution, limiting nutrients and loads to coastal waters.

    PubMed

    Earl, Timothy J; Upton, Graham J G; Nedwell, David B

    2014-07-01

    The work provides robust estimates of nutrient loads (nitrate and phosphate) from all UK catchments: as required by the Water Framework Directive to monitor catchments' health, and to inform management of these environments. To calculate nutrient loads, data for nutrient concentrations and water flow are combined. In the UK, flow data are typically available at hourly intervals at more than 1300 gauging stations but concentration data are collected less frequently (roughly weekly) and at fewer locations (about 280). The sparseness of the concentration data limits the occasions for which load can be calculated, so a mathematical model was derived which was used to interpolate the concentrations between measurements. The model's parameters provide useful information about the annual nutrient concentration cycles within any catchment, and permitted improved estimates of both the annual loads of N and P, and of the N : P ratios, from mainland UK catchments. Data from 1993-2003 showed nitrate loads from UK catchments were generally constant, while orthophosphate loads generally declined. N : P ratios suggested that most catchments in the north and west of the UK were potentially P-limited although a few were potentially N-limited, while many in central and eastern UK oscillated seasonally between N and P limitation. Knowledge of the nutrient which is potentially limiting to biological productivity is a key factor for management of a catchment's nutrient loads. Calculations of nutrient export loads to coastal regions showed that UK catchments contributed only about 16.5% of total fluvial loads of nitrate to the North Sea, or about 3% of the total N loads when inputs from the Atlantic were included. Orthophosphate loads from the UK catchments into the North Sea were only 1.7% of the total P inputs from rivers and the Atlantic but did not include riverine inputs of P adsorbed to particles.

  11. [Variability of breathing pattern during inspiratory elastic load].

    PubMed

    D'Negri, Carlos E; Pessolano, Fernando A; De Vito, Eduardo L

    2009-01-01

    In humans, lung ventilation exhibits breath-to-breath variability and dynamics that are nonlinear, complex and chaotic. Our objective was to characterize the breathing pattern variational activity in anesthetized dogs (n: 8) breathing through threshold inspiratory elastic load (7 to 50 cm H2O). Starting from flow signal and tracheal and esophageal pressures, we analyzed inspiratory time (Ti), timing (expiratory time, Te; total time, Ttot; and Ti/Ttot) and central drive (Vt/Ti) and variables related to it (tidal volume, Vt and pulmonary ventilation, Ve). We measured gross variability (variances), low frequency oscillations (spectral analysis), and short term memory (autocorrelation analysis). Loading decreased variance of the mean values of Te, Ttot, Vt and Vt/Ti (p < 0.05); the mean of variances for Ti/Ttot increased (p < 0.005) while it decreased for Vt and Vt/Ti (p < 0.05). In general, percent of data recordings with low frequency oscillations (OB%) decreased (p < 0.02). During heavy load, timing parameters percent of data recordings with autocorrelations (AU%) did not change, but Vt and its related parameters decreased their AU% (p < 0.005). There was a positive correlation (r: 0.955, p < 0.001) between the existence of low frequency oscillations and autocorrelations for Vt and its related parameters, while timing variables did not show such a correlation. In conclusion, threshold elastic load induced a monotonous respiratory pattern. The short term memory decreased during inspiratory stage while increased during expiratory stage. These changes occurred during anesthesia suggesting that certain suprapontine structures may not be obligatory to induce them.

  12. Maximum and minimum return losses from a passive two-port network terminated with a mismatched load

    NASA Technical Reports Server (NTRS)

    Otoshi, T. Y.

    1993-01-01

    This article presents an analytical method for determining the exact distance a load is required to be offset from a passive two-port network to obtain maximum or minimum return losses from the terminated two-port network. Equations are derived in terms of two-port network S-parameters and load reflection coefficient. The equations are useful for predicting worst-case performances of some types of networks that are terminated with offset short-circuit loads.

  13. 30 CFR 75.1318 - Loading boreholes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) When loading boreholes drilled at an angle of 45 degrees or greater from the horizontal in solid rock or loading long holes drilled upward in anthracite mines— (1) The first cartridge in each...

  14. 30 CFR 75.1318 - Loading boreholes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) When loading boreholes drilled at an angle of 45 degrees or greater from the horizontal in solid rock or loading long holes drilled upward in anthracite mines— (1) The first cartridge in each...

  15. 30 CFR 75.1318 - Loading boreholes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) When loading boreholes drilled at an angle of 45 degrees or greater from the horizontal in solid rock or loading long holes drilled upward in anthracite mines— (1) The first cartridge in each...

  16. 30 CFR 75.1318 - Loading boreholes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) When loading boreholes drilled at an angle of 45 degrees or greater from the horizontal in solid rock or loading long holes drilled upward in anthracite mines— (1) The first cartridge in each...

  17. 30 CFR 75.1318 - Loading boreholes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) When loading boreholes drilled at an angle of 45 degrees or greater from the horizontal in solid rock or loading long holes drilled upward in anthracite mines— (1) The first cartridge in each...

  18. 30 CFR 56.6600 - Loading practices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Electricity § 56.6600 Loading practices. If extraneous electricity is suspected in an area where electric... levels of extraneous electricity are found, the source shall be determined and no loading shall...

  19. 30 CFR 56.6600 - Loading practices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Electricity § 56.6600 Loading practices. If extraneous electricity is suspected in an area where electric... levels of extraneous electricity are found, the source shall be determined and no loading shall...

  20. 30 CFR 56.6600 - Loading practices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Electricity § 56.6600 Loading practices. If extraneous electricity is suspected in an area where electric... levels of extraneous electricity are found, the source shall be determined and no loading shall...