Modellierung der Formstoffströme beim Vollformgießen

Im Rahmen dieser Arbeit wurde mit Hilfe von Distinct Element Methode und PFC3D-Programm eine 3D-Modellierung der Formstoffströme bei der Formherstellung, indem es zur Sandverdichtung unter der Vibrationseinwirkung kommt, für das Vollformgießen durchgeführt. Hierfür wurden die Fließeigenschaften des trockenen binderfreien Sandes überprüft, mit PFC3D modelliert und eine gute Übereinstimmung zwischen dem realen Sand und dem modellierten Stoff erreicht. Dadurch war es möglich, diese Modellierung für die Untersuchungen des Sandverhaltens unter Vibration zu verwenden und die Sandströmungen im Formbehälter zu beobachten. Die theoretischen Ergebnisse des Simulationsprozesses haben gezeigt, dass die durchgeführte Modellierung nicht nur die Auswahl der optimalen Vibrationsparameter bei der Formherstellung für das Vollformgießen, sondern auch die allgemeine Anwendung des mathematischen Modells für den trockenen binderfreien Sand möglich macht

Research of the process of air separation of grain material in a vertical zigzag channel

The aim of the research is to determine ways to improve the efficiency of grain materials pneumatic separation based on the study of the interaction mechanism of grains with the air flow in the channel elements, which are inclined sections of the air duct. The paper considers a modified separation method that separates the grain material according to the aerodynamic properties of the components in a vertical zigzag air channel in an aerodynamic and gravitational field. The studies were carried out by means of mathematical modeling followed by experimental confirmation of the modeling results. A computer mathematical model was created in the MathCad 13 application package to determine the parameters of the zigzag aspiration channel. This model describes the influx of parameters in the channel (width, height, cut of the zigzag ledge to the horizon, edge of the zigzag ledge) on the nature of the grain trajectory. As a result of the numerical simulation process using the mathematical package Mathematica, dependence was obtained to determine the trajectory of motion depending on the angular velocity. An increase in the pneumatic separation effect during the grain mixtures division due to the influence of the Magnus effect was established as a result of experimental studies. The design of a zigzag separator with an annular channel section has been improved based of the research carried out

Якщо позиватися, то як?

OBJECTIVE: to investigate the association of life events during pregnancy with change in antenatal anxiety and depression symptoms. We distinguished pregnancy related and non-pregnancy related events and assessed specificity of these associations for depressive or anxious symptoms. In addition, we investigated whether the associations were affected by personality or childhood adversities. DESIGN: observational prospective cohort study SETTING: primary and secondary obstetric care centres in the Netherlands PARTICIPANTS: 1603 women during their first trimester of pregnancy between May 2010 and May 2012 MEASUREMENTS AND FINDINGS: we performed linear regression analyses to test the associations of pregnancy related, non-pregnancy related life events, childhood adversities and the personality traits neuroticism and extraversion with the change in symptoms of anxiety (State Trait Anxiety Inventory) and depression (Edinburgh Postnatal Depression Scale) from week 12 to week 36. Life events during pregnancy were associated with increasing antenatal symptoms of anxiety and depression. Effect sizes associated with the highest numbers of events observed ranged from 0.59 to 1.31. Pregnancy related events were specifically associated with increasing symptoms of anxiety (p=0.009), whereas non-pregnancy related events were merely associated with an increase in symptoms of depression (p<0.001). Neither personality traits nor childhood trauma influenced the associations under study. KEY CONCLUSIONS: the most important finding is that pregnancy related life events during pregnancy increase levels of antenatal anxiety, whereas depression levels increase when women experience life events that are unrelated to pregnancy. Furthermore, non-pregnancy related events show stronger associations with increases in symptoms of anxiety or depression compared to pregnancy related events. IMPLICATIONS FOR PRACTICE: our findings may help midwives to tailor psychosocial care to the specific risks of the pregnant woman which may eventually have a positive impact on the health of mother and child

Теоретичне обґрунтування та ідентифікація процесів тепломасообміну у вібраційній сушарці з ІЧ-енергопідведенням

The paper contains theoretical substantiation of the processes of radiation-convective heat and mass transfer between all the defining objects inside the vibration dryer with IR energy supply. The presented equations, developed on the basis of the heat and material balance, describe the basic dynamic characteristics of the drying mode for oil-bearing grain material in a continuously operating IR dryer.Since there is no exact analytic solution of the presented mathematical model shaped as a system of differential equations with partial derivatives, the authors propose an approximate solution. The latter allows identifying the dependences between the distribution of temperature and moisture content of grain and oil-containing materials along the length of the dryer for any moment of time.The numerical solution of the reduced mathematical model is possible only with the presence of certain interconnected kinetic coefficients. The kinetic coefficients can not be found experimentally by direct measurements; therefore, the article proposes a method to overcome these difficulties. The presented approximate analytical solution of the synthesized mathematical model, with the use of the method of inverse problems, has allowed determining sets of coefficients by the results of the experimental identification of dehydration. In the future, experimentally identified parametric complexes of the model can be used in the analysis of the drying process for approximate solutions or for further exact numerical solution.Experimental studies of dehydration of grain material have proved that when the power of an IR source is increased from 400 to 500 W, the time for drying from the initial moisture content of 11 % to 8.75 % decreases from 9 to 7 minutes. It is determined that the Rebinder effect characterizing the dampness and thermal properties of the material decreases with a decrease in the moisture content from 0.04 at 11 % to 0.01 at 9 %. This is interesting from the practical point of view as the obtained results and the developed mathematical model can be used for increasing the energy efficiency of the processes of thermal drying in typical facilities that prepare oil-bearing grain materials for their processing.Теоретически обоснованы процессы радиационно-конвективного тепломассообмена между всеми определяющими объектами внутри вибрационной сушилки с ИК-энергопводом. На основе теплового и материального балансов определены уравнения, описывающие основные динамические характеристики режима сушки маслосодержащего зернового материала в непрерывно действующей ИК-сушилке.В связи с тем, что точного аналитического решения представленной математической модели в виде системы дифференциальных уравнений в частных производных не существует, предложено приближенное решение. Оно позволяет идентифицировать зависимости распределения температуры и влагосодержания зернового и маслосодержащего материала по длине сушилки для любого момента времени.Численное решение приведенной математической модели возможно только при наличии определенных взаимосвязанных кинетических коэффициентов. Кинетические коэффициенты экспериментально прямыми измерениями найти невозможно, поэтому в статье предложен метод преодоления этих трудностей. На основе представленного приближенного аналитического решения синтезированной математической модели, с использованием метода обратных задач, определяются комплексы коэффициентов по результатам экспериментальной идентификации процесса обезвоживания. В дальнейшем экспериментально идентифицированные параметрические комплексы модели можно использовать при анализе процесса сушки на приближенных решениях или для дальнейшего точного численного решения.На основе экспериментальных исследований обезвоживания зерноматериала установлено, что при увеличении мощности ИК-источника от 400 до 500Вт время сушки с начальной влажности материала 11 % до 8,75 % уменьшается с 9 до 7 минут. Определено, что критерий Ребиндера, характеризующий влаготепловые характеристики материала, уменьшается при уменьшении его влажности из величины 0,04 при 11 % до 0,01 при 9 %. Это интересно с практической точки зрения и дает возможность использовать полученные результаты и математическую модель при энергетическом совершенствовании реализации процессов термической сушки в типичных объектах подготовки к переработке маслосодержащего зерноматериалаТеоретично обґрунтовано процеси радіаційно-конвективного тепломасообміну між усіма визначальними об’єктами всередині вібраційної сушарки з ІЧ-енергопідведенням. На основі теплового і матеріального балансів визначено рівняння, які описують основні динамічні характеристики режиму сушіння олієвмісного зернового матеріалу в безперервно діючій ІЧ-сущарці. У зв’язку з тим, що точного аналітичного розв’язку представленої математичної моделі у вигляді системи диференціальних рівнянь у частинних похідних не існує. Запропоноване наближене рішення дозволяє ідентифікувати залежності розподілу температури і вологовмісту зернового та олієвмісного матеріалу за довжиною сушарки для будь-якого моменту часу.Чисельний розв’язок наведеної математичної моделі можливий лише при наявності визначених взаємопов’язаних кінетичних коефіцієнтів. Кінетичні коефіцієнти експериментально прямими вимірами знайти не можливо, тому у статті запропоновано метод подолання цих труднощів. На основі представленого наближеного аналітичного розв’язку синтезованої математичної моделі, з використанням методу обернених задач визначаються комплекси коефіцієнтів за результатами експериментальної ідентифікації процесу зневоднення. В подальшому експериментально ідентифіковані параметричні комплекси моделі можливо використовувати при аналізі процесу сушіння на наближених розв’язках або для подальшого точного чисельного розв’язку.На основі експериментальних досліджень зневоднення зерноматеріалу встановлено, що при збільшенні потужності ІЧ-джерела від 400 до 500Вт час сушіння з початкової вологості матеріалу 11 % до 8,75 % зменшується з 9 до 7 хвилин. Визначено, що критерій Ребіндера, який характеризує вологотеплові характеристики матеріалу, зменшується при зменшенні його вологості з величини 0,04 при 11 % до 0,01 при 9 %. Це є цікавим з практичної точки зору і дає можливість використовувати отримані результати і математичну модель при енергетичному удосконаленні реалізації процесів термічного сушіння в типових об’єктах підготовки до переробки олієвмісних зерноматеріалі

The Association Between Body Mass Index and Anxious Arousal, Depressive, and Insomnia Symptoms Among World Trade Center Responders

Elevations in body mass index (BMI) among World Trade Center (WTC) responders may be associated with poor mental health outcomes. The current study examined the association of BMI with anxious arousal, depressive, and insomnia symptoms among this group. Participants were 412 WTC responders (89.4% male, Mage = 55.3 years, SD = 8.66) who completed health monitoring assessments (self-report and objective) as part of the Long Island site of the WTC Health Program (LI-WTC-HP). Results suggested BMI was statistically significant only in relation to anxious arousal (sr2 = .02, p = .008), after accounting for age and sex. The current study suggests that weight management programs may aid in promoting additional benefits for WTC responders by reducing anxious arousal symptoms as a function of reduced BMI

Building data marts to analyze university faculty activities using power BI

Evaluating the performance of university faculty is a hard task because of the diversity of the work performed. The authors assume that the founder of the university evaluates the effectiveness of the university according to performing the teaching staff. The aim of the study is to improve the monitoring of key performance indicators of the university teaching staff based on data management. The authors present an information system to support decision-making related to the teaching staff at Kemerovo State University. The authors of the paper describe creating such a system using Business Intelligence technologies step by step. The authors identified data sources, designed the structure of the data mart and built ETL-processes for its filling, implemented various analytical dashboards. Implementing the information system in the daily activities of the university allows responding promptly to changes in the key indicators, forecasting their further change, deciding on activation of efforts in the chosen direction or types of work

Inferring trajectories of psychotic disorders using dynamic causal modeling

Introduction: Illness course plays a crucial role in delineating psychiatric disorders. However, existing nosologies consider only its most basic features (e.g., symptom sequence, duration). We developed a Dynamic Causal Model (DCM) that characterizes course patterns more fully using dense timeseries data. This foundational study introduces the new modeling approach and evaluates its validity using empirical and simulated data. Methods: A three-level DCM was constructed to model how latent dynamics produce symptoms of depression, mania, and psychosis. This model was fit to symptom scores of nine patients collected prospectively over four years, following first hospitalization. Simulated subjects based on these empirical data were used to evaluate model parameters at the subject-level. At the group-level, we tested the accuracy with which the DCM can estimate the latent course patterns using Parametric Empirical Bayes (PEB) and leave-one-out cross-validation. Results: Analyses of empirical data showed that DCM accurately captured symptom trajectories for all nine subjects. Simulation results showed that parameters could be estimated accurately (correlations between generative and estimated parameters >= 0.76). Moreover, the model could distinguish different latent course patterns, with PEB correctly assigning simulated patients for eight of nine course patterns. When testing any pair of two specific course patterns using leave-one-out cross-validation, 30 out of 36 pairs showed a moderate or high out-of-samples correlation between the true group-membership and the estimated group-membership values. Conclusion: DCM has been widely used in neuroscience to infer latent neuronal processes from neuroimaging data. Our findings highlight the potential of adopting this methodology for modeling symptom trajectories to explicate nosologic entities, temporal patterns that define them, and facilitate personalized treatment

Cognitive impairment among World Trade Center responders: Long-term implications of re-experiencing the 9/11 terrorist attacks

AbstractIntroductionDuring the World Trade Center (WTC) attacks, responders who helped in search, rescue, and recovery endured multiple traumatic and toxic exposures. One-fifth subsequently developed post-traumatic stress disorder (PTSD). PTSD has been linked to dementia in veterans. This study examined the association between WTC-related PTSD and cognitive impairment (CI) in WTC responders.MethodsA one-third sample of responders (N = 818) reporting for annual monitoring visits were screened for cognitive impairment and dementia using the Montreal Cognitive Assessment from January 2014–April 2015. Concurrent diagnoses of PTSD and major depressive disorder (MDD), as well as serial PTSD and depressive symptom inventories, collected since 2002, were examined in relation to current CI.ResultsApproximately 12.8% and 1.2% of responders in this sample respectively had scores indicative of CI and possible dementia. Current PTSD and MDD were associated with CI. Longitudinal results revealed that re-experiencing symptoms were consistently associated with CI (aRR = 2.88, 95% confidence interval = 1.35–6.22), whereas longitudinal increases in other PTSD and depressive symptoms in the years before screening were evident only among those with CI.ConclusionsAnalyses replicated results from Veterans studies and further highlighted the importance of re-experiencing symptoms, a major component of PTSD that was consistently predictive of CI 14 years later. Clinicians should monitor CI when treating individuals with chronic PTSD