Parameter calibration in a model of the secondary settling tank in wastewater treatment

In a wastewater treatment plant, particles (activated sludge) are separated from the liquid in a process called continuous sedimentation. This process is of crucial importance when purifying water in a wastewater treatment plant. This report will focus on a special case of sedimentation, namely batch sedimentation, which means that no flux into or out from the sedimentation tank are present. The goal is to implement and calibrate a mathematical model, that describes the phenomenon. During batch sedimentation, both in reality and in the model world, the conservation law implies solutions with shock waves. These shock waves set high standard for the numerical method used in the implementation. A specific model for this purpose is going to be used. Some interesting results were found about the induction period in the initial phase of the sedimentation. Further improvements were observed when dispersion was taken into account in the model. Nevertheless, there is no doubt about the fact that more research in this area is needed

The Causal Effect of Parent’s Schooling on Children’s Schooling: A Comparison of Estimation Methods

Recent studies that aim to estimate the causal link between the education of parents and their children provide evidence that is far from conclusive. This paper explores why. There are a number of possible explanations. One is that these studies rely on different data sources, gathered in different countries at different times. Another one is that these studies use different identification strategies. Three identification strategies that are currently in use rely on: identical twins; adoptees; and instrumental variables. In this paper we apply each of these three strategies to one particular Swedish data set. The purpose is threefold: (i) explain the disparate evidence in the recent literature; (ii) learn more about the quality of each identification procedure; and (iii) get at better perspective about intergenerational effects of education. We find that the three identification strategies all produce intergenerational schooling estimates that are lower than the corresponding OLS estimates, indicating the importance of accounting for ability bias. But interestingly, when applying the three methods to the same data set, we are able to fully replicate the discrepancies across methods found in the previous literature. Our findings therefore indicate that the estimated impact of parental education on that of their child in Sweden does depend on identification, which suggests that country and cohort differences do not lie behind the observed disparities. Finally, we conclude that income is a mechanism linking parent’s and children’s schooling, that can partly explain the diverging results across methods.intergenerational mobility, education, causation, selection, identification

The Causal Effect of Parents' Schooling on Children's Schooling - A Comparison of Estimation Methods

We review the empirical literature that estimates the causal effect of parent’s schooling on child’s schooling, and conclude that estimates differ across studies. We then consider three explanations for why this is: (a) idiosyncratic differences in data sets; (b) differences in remaining biases between different identification strategies; and (c) differences across identification strategies in their ability to make out-of-sample predictions. We conclude that discrepancies in past studies can be explained by violations of identifying assumptions. Our reading of past evidence, together with an application to Swedish register data, suggests that intergenerational schooling associations are largely driven by selection. Parental schooling constitutes a large part of the parental nurture effect, but as a whole does not play a large role.intergenerational mobility, education, causation, selection, identification

Design of a Pole Climbing Unit

Temporary surveillance with an easily deployable surveillance unit can give a tactical advantage for police in situations when big crowds suddenly gather. It can also be used by fire department during fires or in the private security sector on construction sites and other such temporary areas requiring surveillance. This report describes the process of developing the climbing system for such a surveillance unit. Firstly a pre-study is made to determine what is required of the climbing system. Poles are studied online and by walking around in different cities. Also researched in the pre-study is possible competition. Following the pre-study is research on possible customer needs. Concept generation follows where concepts compete against each other in concept screening and concept scoring based on the initial research. The final winner is developed to a working prototype. The prototype uses belts to tighten itself to a pole in two different places. By holding the pole with one belt the other belt can be lifted which allows the robot to climb. The final prototype works but needs improvements before it is market ready.Temporary surveillance with an easily deployable camera can give a tactical advantage for police in riots or similar situations when big crowds suddenly gather, or for the fire department when a fire breaks out. This is a brief description of the development for a prototype pole climbing unit where a camera in a later product can be attached

Molecular Dynamics Simulations of Phospholipid Bilayers with Cholesterol

AbstractTo investigate the microscopic interactions between cholesterol and lipids in biological membranes, we have performed a series of molecular dynamics simulations of large membranes with different levels of cholesterol content. The simulations extend to 10ns, and were performed with hydrated dipalmitoylphosphatidylcholine (DPPC) bilayers. The bilayers contain 1024 lipids of which 0–40% were cholesterol and the rest DPPC. The effects of cholesterol on the structure and mesoscopic dynamics of the bilayer were monitored as a function of cholesterol concentration. The main effects observed are a significant ordering of the DPPC chains (as monitored by NMR type order parameters), a reduced fraction of gauche bonds, a reduced surface area per lipid, less undulations—corresponding to an increased bending modulus for the membrane, smaller area fluctuations, and a reduced lateral diffusion of DPPC-lipids as well as cholesterols

Moniosaisen kaiuttimen muotoiluprosessi

Tässä opinnäytteessä tarkastellaan muotoilullisten lähtökohtien vaikutuksia kaiutinsuunnitteluun. Vallitseville kaiutinratkaisuille on etsitty vaihtoehtoja muotoilun keinoin. Opinnäyte toteutettiin käytännön prosessina, jonka tuloksena syntyi kaiutinprototyyppi. Projektissa tutkittiin moniosaisuuden vaikutuksia kaiuttimen visualisuuteen sekä käytettävyyteen. Sen avulla pystyttiin tuomaan uudenlaisia vaihtoehtoja kaiuttimien sisutukselliseen rooliin sekä äänelliseen työnjakoon. Myös materiaaleista sekä valmistustekniikoista hankittu tietotaito ja kokemukset ovat luoneet pohjaa tulevaisuuden kehitystyölle. Kaiutinsuunnittelua voidaan jatkossa tehdä entistä innovatiivisemmin

NOMAD-Ref: visualization, deformation and refinement of macromolecular structures based on all-atom normal mode analysis

Normal mode analysis (NMA) is an efficient way to study collective motions in biomolecules that bypasses the computational costs and many limitations associated with full dynamics simulations. The NOMAD-Ref web server presented here provides tools for online calculation of the normal modes of large molecules (up to 100 000 atoms) maintaining a full all-atom representation of their structures, as well as access to a number of programs that utilize these collective motions for deformation and refinement of biomolecular structures. Applications include the generation of sets of decoys with correct stereochemistry but arbitrary large amplitude movements, the quantification of the overlap between alternative conformations of a molecule, refinement of structures against experimental data, such as X-ray diffraction structure factors or Cryo-EM maps and optimization of docked complexes by modeling receptor/ligand flexibility through normal mode motions. The server can be accessed at the URL