On the durability of cores and rest roll dynamics

The printing industry is facing the same challenges as many other industries, in that demand is increasing for its processes to run faster and more reliably. Roll weight, width and web speed are steadily increasing which put increasing demands on unwinding stability and durability of cores.Durability and especially the unwinding stability of cores is one of the most important topics when designing new wider printing machine unwinders. The majority of paper and printing industry processes run with recyclable paperboard cores. A change in core geometry could lead to significant retrofitting costs for both the paper mill and printer.Winder and printing press reel stand design, especially with regards to chucks, can have a considerable effect on the maximum tolerated roll weight and unwinding web speed. It is important to use the right combinations of cores and chucks to maximize performance and cost savings.The risk of rest reel explosions increases rapidly in the vicinity of the resonance frequency of a rest reel. It is important to know the safe web speed ranges in different situations. The range of safe web speed can be estimated according to the presented theory. The maximum tolerated mid span vibration is typically +/-5 mm.Cores must also withstand the alternating, cyclic roll supporting stresses during winding and unwinding. The risk of core failure can be minimized by using cores which have sufficiently high dynamic delamination strength (roll weight capacity).The durability of cores can be estimated by dynamic chuck load capacity tests and by testing cores in simulated winding-unwinding conditions. The simulation test results are reduced to correspond to certain confidence levels by reducing the simulation curve by a certain number of standard deviations.With a sufficient number of chuck load capacity tests, statistically reduced winding-unwinding simulation results and test data concerning behavior of cores in the vicinity of resonance, core recommendations can be built for core users as shown here

Study of CD elongation of core in winding

In this paper the elongation of a core in a roll bottom is studied experimentally and theoretically. The CD elongation effects are of interest especially because they are known to contribute prominently to a two-drum winder vibration or roll instability phenomenon called bouncing in the paper industry.Analytical and numerical calculation models are used to study the effect of different geometrical, material, etc., parameters on the core and paper CD elongation. If the free lateral elongation and rotation is allowed and the friction between paper and the core is neglected, the radial and tangential stresses of the core are due to the radial pressure only. The lateral and shear stresses are equal to zero and the elongation depends on the pressure, Poisson's ratios in the thickness-machine and thickness-cross directions, elastic modulus in the thickness and tangential directions and the geometry. If the lateral frictional farces between the paper and core are also taken into account, another, equally effective elongation mechanism is introduced.The measurements of the paper and core elongation are in accordance with the calculated results. In practice, cores expand typically +/-1 mm/m depending on the tightness of the roll bottom and core properties. This study shows that the core elongation increases linearly with the radial pressure. Small diameter cores lengthen less than large cores. Cores with thicker wall thickness lengthen less than thinner cores, and cores with a bigger winding angle lengthen less than cores with a smaller winding angle (conventional cores).The radial moduli of paper and the core wall also play an important role in the elongation of the core. Preliminary studies suggest that the softer the paper the more it tends to widen. According to paper stack modulus measurements, the radial modulus of paper layers in the roll bottom can be less than 100 MPa, even with high winding pressures. The radial elastic modulus of the core wall is usually 100 - 200 MPa or even greater depending on the core type. It is possible that the frictional force between the core and paper could force the core to elongate more than it would without paper

Global epidemiology of hip fractures: a study protocol using a common analytical platform among multiple countries

INTRODUCTION: Hip fractures are associated with a high burden of morbidity and mortality. Globally, there is wide variation in the incidence of hip fracture in people aged 50 years and older. Longitudinal and cross-geographical comparisons of health data can provide insights on aetiology, risk factors, and healthcare practices. However, systematic reviews of studies that use different methods and study periods do not permit direct comparison across geographical regions. Thus, the objective of this study is to investigate global secular trends in hip fracture incidence, mortality and use of postfracture pharmacological treatment across Asia, Oceania, North and South America, and Western and Northern Europe using a unified methodology applied to health records. METHODS AND ANALYSIS: This retrospective cohort study will use a common protocol and an analytical common data model approach to examine incidence of hip fracture across population-based databases in different geographical regions and healthcare settings. The study period will be from 2005 to 2018 subject to data availability in study sites. Patients aged 50 years and older and hospitalised due to hip fracture during the study period will be included. The primary outcome will be expressed as the annual incidence of hip fracture. Secondary outcomes will be the pharmacological treatment rate and mortality within 12 months following initial hip fracture by year. For the primary outcome, crude and standardised incidence of hip fracture will be reported. Linear regression will be used to test for time trends in the annual incidence. For secondary outcomes, the crude mortality and standardised mortality incidence will be reported. ETHICS AND DISSEMINATION: Each participating site will follow the relevant local ethics and regulatory frameworks for study approval. The results of the study will be submitted for peer-reviewed scientific publications and presented at scientific conferences

Conduct disorder in girls: neighborhoods, family characteristics, and parenting behaviors

<p>Abstract</p> <p>Background</p> <p>Little is known about the social context of girls with conduct disorder (CD), a question of increasing importance to clinicians and researchers. The purpose of this study was to examine the associations between three social context domains (neighborhood, family characteristics, and parenting behaviors) and CD in adolescent girls, additionally testing for race moderation effects. We predicted that disadvantaged neighborhoods, family characteristics such as parental marital status, and parenting behaviors such as negative discipline would characterize girls with CD. We also hypothesized that parenting behaviors would mediate the associations between neighborhood and family characteristics and CD.</p> <p>Methods</p> <p>We recruited 93 15–17 year-old girls from the community and used a structured psychiatric interview to assign participants to a CD group (n = 52) or a demographically matched group with no psychiatric disorder (n = 41). Each girl and parent also filled out questionnaires about neighborhood, family characteristics, and parenting behaviors.</p> <p>Results</p> <p>Neighborhood quality was not associated with CD in girls. Some family characteristics (parental antisociality) and parenting behaviors (levels of family activities and negative discipline) were characteristic of girls with CD, but notll. There was no moderation by race. Our hypothesis that the association between family characteristics and CD would be mediated by parenting behaviors was not supported.</p> <p>Conclusion</p> <p>This study expanded upon previous research by investigating multiple social context domains in girls with CD and by selecting a comparison group who were not different in age, social class, or race. When these factors are thus controlled, CD in adolescent girls is not significantly associated with neighborhood, but is associated with some family characteristics and some types of parental behaviors. However, the mechanisms underlying these relationships need to be further investigated. We discuss possible explanations for our findings and suggest directions for future research.</p

Conhecimento vocal e a importância da voz como recurso pedagógico na perspectiva de professores universitários

OBJETIVO: investigar o conhecimento vocal e sua importância como recurso pedagógico em professores universitários. MÉTODOS: participaram 112 docentes, média de 46,60 anos, 35,7% do sexo masculino e 64,3% do feminino, 66,1% doutores. Utilizou-se o questionário Condições de Produção Vocal-Professor, adaptado pela pesquisadora, além da inserção de novas questões abertas e fechadas de interesse para o estudo, as quais foram assinaladas em uma escala analógica de zero a dez. Foram coletadas amostras de voz dos professores e analisadas por avaliação fonoaudiológica. As questões fechadas receberam tratamento estatístico, considerando-se a média das notas autorreferidas, em cada variável pesquisada. Os resultados foram correlacionados a partir das variáveis: sexo e presença/ausência de alteração vocal. Organizaram-se as respostas das questões abertas por similaridade de conteúdo e frequência de ocorrência. RESULTADOS: constatou-se associação significante entre sexo feminino e voz fina, fadiga e perda da voz; presença de distúrbio de voz e autorreferência à voz fraca, rouquidão, voz insuficiente para o trabalho e fadiga vocal. Os professores participaram da pesquisa para colaborar e melhorar a voz na docência; mudariam suas vozes nos aspectos de intensidade, tom e modulação; os recursos vocais mais utilizados em sala de aula foram variação de tom e intensidade, modulação e pausas; e quando a voz está alterada, recorrem ao repouso vocal e à hidratação. Atribuiu-se a média de 9,42 para a voz como recurso pedagógico. CONCLUSÃO: o conhecimento vocal dos participantes foi apropriado e eles avaliaram a voz como recurso pedagógico essencial

Global epidemiology of hip fractures: a study protocol using a common analytical platform among multiple countries

INTRODUCTION: Hip fractures are associated with a high burden of morbidity and mortality. Globally, there is wide variation in the incidence of hip fracture in people aged 50 years and older. Longitudinal and cross-geographical comparisons of health data can provide insights on aetiology, risk factors, and healthcare practices. However, systematic reviews of studies that use different methods and study periods do not permit direct comparison across geographical regions. Thus, the objective of this study is to investigate global secular trends in hip fracture incidence, mortality and use of postfracture pharmacological treatment across Asia, Oceania, North and South America, and Western and Northern Europe using a unified methodology applied to health records. METHODS AND ANALYSIS: This retrospective cohort study will use a common protocol and an analytical common data model approach to examine incidence of hip fracture across population-based databases in different geographical regions and healthcare settings. The study period will be from 2005 to 2018 subject to data availability in study sites. Patients aged 50 years and older and hospitalised due to hip fracture during the study period will be included. The primary outcome will be expressed as the annual incidence of hip fracture. Secondary outcomes will be the pharmacological treatment rate and mortality within 12 months following initial hip fracture by year. For the primary outcome, crude and standardised incidence of hip fracture will be reported. Linear regression will be used to test for time trends in the annual incidence. For secondary outcomes, the crude mortality and standardised mortality incidence will be reported. ETHICS AND DISSEMINATION: Each participating site will follow the relevant local ethics and regulatory frameworks for study approval. The results of the study will be submitted for peer-reviewed scientific publications and presented at scientific conferences

Attention-deficit hyperactivity disorder and nonsuicidal self-injury in a clinical sample of adolescents: the role of comorbidities and gender.

BACKGROUND: The aim of the present study was to investigate the possible association between attention-deficit hyperactivity disorder (ADHD) and non-suicidal self-injury (NSSI) with special focus on the role of comorbidities and gender in a clinical sample of adolescents with both a dimensional and a categorical approach to psychopathology. METHODS: Using a structured interview, the Mini International Neuropsychiatric Interview Kid and a self-rated questionnaire, the Deliberate Self-Harm Inventory, the authors examined 202 inpatient adolescents (aged: 13-18 years) in the Vadaskert Child and Adolescent Psychiatric Hospital and Outpatient Clinic, Budapest, Hungary. Descriptive statistics, Mann-Whitney U test, chi-square test and mediator model were used. RESULTS: Fifty-two adolescents met full criteria for ADHD and a further 77 showed symptoms of ADHD at the subthreshold level. From the 52 adolescents diagnosed with ADHD, 35 (67.30%) had NSSI, of whom there were significantly more girls than boys, boys: n = 10 (28.60%), girls: n = 25 (71.40%) ((chi(2)(1) = 10.643 p < .001 varphi = .452). Multiple mediation analyses resulted in a moderated mediation model in which the relationship between symptoms of ADHD and the prevalence of current NSSI was fully mediated by the symptoms of comorbid conditions in both sex. Significant mediators were the symptoms of affective and psychotic disorders and suicidality in both sexes and the symptoms of alcohol abuse/dependence disorders in girls. CONCLUSIONS: ADHD symptoms are associated with an increased risk of NSSI in adolescents, especially in the case of girls. Our findings suggest that clinicians should routinely screen for the symptoms of ADHD and comorbidity, with a special focus on the symptoms of affective disorders and alcohol abuse/dependence psychotic symptoms to prevent NSSI