Modeling and control of various styles of paper machine headboxes

In this thesis non-linear mathematical models of a typical paper machine approach system with three different styles of headboxes are presented. The non-linear models include the dynamics of the fan pump, DC motor, pressure screen, attenuator, headbox and piping sections. Headbox models of a hydraulic and two air-cushioned headboxes (traditional and internal weir) are covered. The models were developed from first principles. Total head at the headbox slice is controlled by manipulation of the applied armature voltage of the variable speed DC motor. Stock level in the air-cushioned headboxes is controlled by manipulation of the air pad bleed valve. Simple analog Proportional-Integral (PI) controllers were selected to track without offset the desired level and total head set-points. The downhill simplex method developed by Nelder and Mead was used for controller fine-tuning. The performance criterion was the integrated absolute error (IAE) with weighting factors for both pressure and level loops. Frequency responses for each model were generated using a commercially available software program called EASY5™. Step and frequency response plots were generated at operating points of 60, 75 and 90 kPa to evaluate the non-linear behaviour of each headbox model. The step response plots highlighted the strong interaction that exists between level and pressure loops of the air-cushioned headboxes. With the PI gains used the transient responses of the pressure loop of all headboxes were underdamped. The open-loop frequency responses in all models illustrated the non-linearity of the centrifugal fan pump. In addition the effect of the fan pump on the stock level and total head was found to be strong. The effect of the bleed valve on the stock level was also determined to be strong. With the traditional headbox the effect of the bleed valve on the total head was found to be weak whereas with the weir headbox at low frequencies it was found to be strong. One-way decoupling was proposed to improve the control performance of the aircushioned headbox level loop. For simplicity a lead / lag compensator was selected to approximate the ideal decoupling frequency response determined directly from the open-loop frequency responses. A significant reduction in stock level deviations before and after the addition of one-way decoupling in both the time and frequency domain was observed thereby proving its usefulness when combined with the feedback PI controllers

Combining Models of Root-Zone Hydrology and Geoelectrical Measurements: Recent Advances and Future Prospects

Recent advances in measuring and modeling root water uptake along with refined electrical petrophysical models may help fill the existing gap in hydrological root model parametrization. In this paper, we discuss the choices to be made to combine root-zone hydrology and geoelectrical data with the aim of characterizing the active root zone. For each model and observation type we discuss sources of uncertainty and how they are commonly addressed in a stochastic inversion framework. We point out different degrees of integration in the existing hydrogeophysical approaches to parametrize models of root-zone hydrology. This paper aims at giving emphasis to stochastic approaches, in particular to Data Assimilation (DA) schemes, that are generally identified as the best way to combine geoelectrical data with Root Water Uptake (RWU) models. In addition, the study points out a more suitable objective function taken from the optimal transport theory that better captures complex geometry of root systems. Another pathway for improvement of geoelectrical data integration into RWU models using DA relies on the use of stem based methods as a leverage to introduce more extensive root knowledge into RWU macroscopic hydrological models

Renal Evaluation in Women with Preeclampsia

Background/Aims: Preeclampsia (PE) is a cause of glomerulopathy worldwide. Urinary retinol-binding protein (RBP) is a marker of proximal tubular dysfunction, albuminuria is an endothelial injury marker, urine protein:creatinine ratio (PCR) may have a predictive value for renal disease later in life, and, recently, podocyturia has been proposed as a sensitive tool in pregnancy, but it needs to be tested. The aim of this study was to evaluate renal involvement in PE and healthy pregnancy. Methods: Case-control study with 39 pregnant women assessed after 20 weeks of gestation (25 in the control group, CG, and 14 in the PE group) by performing urinary tests. Results: Mean (±SD) age and gestational age of the CG were 26.9 ± 6.4 years and 37.1 ± 5.0 weeks, and of the PE group 26.4 ± 6.9 years and 30.6 ± 5.6 weeks, respectively (p = 0.001). Mean (±SD) urinary RBP (p = 0.017), albuminuria (p = 0.002), and urinary albumin concentration (UAC) ratio (p = 0.006) of the CG were 0.4 ± 0.7 mg/l, 7.3 ± 6.9 mg/l, and 8.2 ± 6.7 mg/g and of the PE group 2.0 ± 4.4 mg/l, 2,267.4 ± 2,130.8 mg/l (p = 0.002), and 3,778.9 ± 4,296.6 mg/g (p = 0.006), respectively. Mean (±SD) urine PCR in the PE group was 6.7 ± 6.1 g/g (p Conclusions: Urinary RBP, PCR, albuminuria, and UAC ratio were elevated in the PE group in comparison to the CG. Podocyturia did not predict PE

methods and tools for the development of adaptive applications

n/

A Newly Identified Essential Complex, Dre2-Tah18, Controls Mitochondria Integrity and Cell Death after Oxidative Stress in Yeast

A mutated allele of the essential gene TAH18 was previously identified in our laboratory in a genetic screen for new proteins interacting with the DNA polymerase delta in yeast [1]. The present work shows that Tah18 plays a role in response to oxidative stress. After exposure to lethal doses of H2O2, GFP-Tah18 relocalizes to the mitochondria and controls mitochondria integrity and cell death. Dre2, an essential Fe/S cluster protein and homologue of human anti-apoptotic Ciapin1, was identified as a molecular partner of Tah18 in the absence of stress. Moreover, Ciapin1 is able to replace yeast Dre2 in vivo and physically interacts with Tah18. Our results are in favour of an oxidative stress-induced cell death in yeast that involves mitochondria and is controlled by the newly identified Dre2-Tah18 complex

Principles of Hand Fracture Management

The hand is essential in humans for physical manipulation of their surrounding environment. Allowing the ability to grasp, and differentiated from other animals by an opposing thumb, the main functions include both fine and gross motor skills as well as being a key tool for sensing and understanding the immediate surroundings of their owner