<p><a>This dissertation focused on better understanding the fundamental processes that control organic and inorganic contaminant interaction with plastic plumbing pipes. Plastic pipes are increasingly being installed for drinking water plumbing, but their role in affecting drinking water quality has received little study. It is well-known that plastic pipes can sorb and release organic contaminants and be difficult to decontaminate. Several problems were identified in the literature and through discussions with industry: (1) Past guidance issued to communities affected by petroleum contaminated water does not seem to specifically consider plastic plumbing pipe remediation, (2) investigators have also identified heavy metals can accumulate on pipe inner walls, (3) Others have proposed certain heavy metals can catalyze plastic water pipe degradation, (4) No nondestructive cleaning methods were found for removing metal scales from plastic pipes.</a> These topics were a basis for studies conducted because lack of information inhibits greater protection of public health, safety, and welfare.</p> This dissertation involved the application of knowledge and techniques from the environmental engineering and science, polymer engineering, and material science disciplines. Chapter 1 focused on the response of copper and plastic pipes (i.e., chlorinated polyvinylchloride (cPVC), high-density polyethylene (HDPE), crosslinked polyethylene (PEX)) exposed to petroleum contaminated drinking water. Bench-scale results revealed that pipe rinsing followed by a single 3 day water stagnation period removed target monoaromatic hydrocarbons (MAH) from copper pipes, but much longer (<u>></u>15 days) time was required for decontaminating cPVC, HDPC, and PEX pipes. Benzene, trimethylbenzene and polynuclear aromatic hydrocarbons, some of which are not typically considered in drinking water contamination investigations, were found desorbed into clean drinking water from pipes. Future plumbing decontamination guidance should consider the conditions necessary for plastic pipe remediation. Chapter 2 describes the influence of drinking water conditions on heavy metal contaminant – low density polyethylene (LDPE) pellet surface interactions. Mixed metal drinking water solutions were applied and contained Cu, Fe, Mn, Pb and Zn at 30 µg/L. LDPE was selected as the model polymer because of its prior use for piping in Europe, use in bench-scale studies by others, and similarity to products used for the manufacture of more complex materials in the USA (HDPE, PEX). As expected, metal loadings were about 5 times greater for aged LDPE pellets suspended in solution compared to new LDPE pellets. This difference was attributed to the aged plastic surfaces having oxygen containing functional groups, increased surface area, and enhanced hydrophilicity. Metal loading was lower at pH >9.5 and in the presence of dissolved organic contaminants. The presence of free chlorine and corrosion inhibitor also decreased metal adsorption onto LDPE pellets. These factors likely enabled metal precipitation thereby not allowing metal species to adsorb to LDPE pellets suspended in water. XPS results showed deposited metals (i.e., Cu, Pb, Zn) primarily consisted of hydroxides and oxides. To further understand heavy metal – plastic pipe interactions, Chapter 3 involved the use of metal and plastic pipe rigs and exhumed PEX plumbing pipes. Exhumed cold and hot water PEX pipes contained a noticeable amount of heavy metals (i.e., most abundant metals were 2049 mg/m² Fe, 400 mg/m² Ca, 438 mg/m² Zn and 150 mg/m² P). Metal release and deposition onto PEX pipe was examined using bench-scale pipe rigs that contained new PEX pipe, brass valves, and copper pipe. Two water matrices (pH 4 and 7.5) and two temperatures (23^oC and 55^oC) were explored. The pH 4 water often accelerated metal leaching from brass valves, and a greater amount of heavy metals deposited on PEX pipes at high water pH and temperature (pH 4 and 55^oC) conditions. Oxygen containing functional groups were detected on PEX pipes connected to a brass valve or a brass valve combined copper pipe, but were not found on PEX pipe only (controls) samples, indicating that certain configurations may facilitate plastic pipe degradation. The last chapter describes the ability of a new lignin derived ligand to remove metal deposits from exhumed PEX plumbing pipes. When the ligand concentration was ≥ 5mM, more than 95% of sorbed metals (i.e., Cu, Fe, Mn, Pb and Zn) were removed. The ligand favored certain metals over others (Cu > Zn > Fe > Mn > Pb) and heavy metal removal mechanisms were proposed. This dissertation provides insights into the role of plastic pipes on drinking water quality. As plastic pipes continue to be installed, it is in the interest of public health, welfare, and safety to understand their role in positively and negatively affecting drinking water safety.

This master’s thesis focuses on rationalization of production line for plastic windows production in RI OKNA a.s. (Inc.). Evaluation of production line’s current estate is being done as well as weak point detection. On these bases some new variations for improvement are being suggested. The winning variation is drown up into the technological project and put through an economical evaluation.

No description available.

This master's thesis is focused on analyzing problems during the execution of contracts selected company, which deals with custom manufacturing thermoplastic injection molding. The thesis proposed possible solutions for identified problems.

Die Laserablation gekoppelt mit der Massenspektrometrie mit induktiv gekoppeltem Plasma ist eine vielversprechende direkte Feststofftechnik, die sich jedoch bei der Analyse von Kunststoffen wegen des Mangels an matrixangepassten zertifizierten Referenzmaterialien nicht durchsetzen konnte. Vorherige Arbeiten belegen polymerabhängige Abtragsraten. Das oft als interner Standard verwendete Intensitätssignal des Kohlenstoffisotopes 13C zur Korrektur dieser Unterschiede wird in der Literatur kritisch diskutiert. In dieser Arbeit als ein Teil des BMBF-geförderten MaxLaP-Projektes wurden matrixangepasste Standards auf Polyethylen- und Acrylnitril-Butadien-Styrolbasis entwickelt. In diese Standards wurden Br, Cd, Cu, Cr, Fe, Sb in organischer und anorganischer Form ihrer Verbindungen mittels Extrusion eingearbeitet. Die quantitative Zusammensetzung der Materialien wurde mittels ETV-ICP-OES, DC-arc-OES, RFA und ICP-MS nach Mikrowellendruckaufschluss überprüft. Die Verfahren wurden für die Kunststoffanalyse optimiert. Die mikroskopische Homogenität der Einarbeitung wurde mittels µ-SYRFA und LA-ICP-MS untersucht. Zur Untersuchung der Matrixeffekte während der LA-ICP-MS und der matrixunabhängigen Kalibrierung für Kunststoffe wurden der Einfluss der chemischen Verbindung der Additive, die Größe, der bei der Laserablation gebildeten Partikel und die Art des Kunststoffes auf die Laserablation analysiert. Die Korrektur des verschiedenen Materialabtrages über die Verwendung des 13C-Signals konnte für 21 verschiedene Kunststoffe erfolgreich durchgeführt werden. Allerdings zeigen die zugesetzten Additive ein nicht identisches Verhalten hinsichtlich Transport und Ionisierung. Weitere Ergebnisse belegen eine Anreicherung der Additive in verschiedenen Partikelgrößen sowie eine deutlich unterschiedliche Partikelbildung bei Ablationen von verschiedenen polymeren Matrices, was zu einer verstärkten Elementfraktionierung bei einer nicht matrixangepassten Kalibrierung führt. / Laser ablation coupled to a mass spectrometer with inductively coupled plasma (LA-ICP-MS) is a promising direct solid sampling technique. Due to the lack of matrix matched standard materials laser ablation is not well established in polymer analysis. In a recent study a polymer dependent interaction with the laser beam was reported, which resulted in a polymer depending ablation rate. The usage of the carbon-13-signal intensity as internal standard to correct these differences as commonly applied has been critically discussed in literature. In this work as part of a BMBF-supported MaxLaP-project (matrix effects during laser ablation of polymers) matrix matched standards based on polyethylene and acrylonitrile butadiene styrene were developed. In these materials Br, Cd, Cu, Cr, Fe and Sb were incorporated as organic and inorganic compounds through extrusion. Quantitative composition of the materials was determined by ETV-ICP-OES, DC-arc-OES, XRF and ICP-MS after high pressure microwave digestion. Analytical methods were optimized for trace analysis in plastic matrices. Microscopic homogeneity was examined by µ-SyXRF as well as LA-ICP-MS. In order to investigate the matrix effects and to determine the possibility of a matrix independent calibration for plastic materials, the influence of the chemical form of the additives, size of the formed particles and the type of the plastic on the LA-ICP-MS measurements were analyzed. The correction of the material uptake by the carbon-13-signal was successfully applied for 21 different types of plastic. However, different incorporated additives show a different transport and ionization behavior. Furthermore, our results confirm a different enrichment of the additives depending on particle size and a significantly different particle formation for different types of plastic, which leads to a more pronounced elemental fractionation by not using a matrix matched calibration.

Der Vortrag beschreibt wie sich mittels der unterschiedlichen Berechnungsverfahren zur Lösung dynamischer Strukturpobleme der Einschlag eines idealisierten Bruchstücks in eine Schutzwand berechnen lässt. Dies wird mittels zweier kommerzieller FEM-Programme beschrieben: a.) Creo Simulate nutzt zur Lösung die Methode der modalen Superposition, d.h., es können nur lineare dynamische Systeme mit rein modaler Dämpfung berechnet werden. Kontakt zwischen zwei Bauteilen lässt sich damit nicht erfassen. Die unbekannte Kraft-Zeit-Funktion des Einschlagvorganges muss also geeignet abgeschätzt und als äußere Last auf die Schutzwand aufgebracht werden. Je dynamischer der Einschlagvorgang, desto eher wird der Gültigkeitsbereich des zugrunde liegenden linearen Modells verlassen. b.) Abaqus/Explicit nutzt ein direktes Zeitintegrationsverfahren zur schrittweisen Lösung der zugrunde liegenden Differentialgleichung, die keine tangentiale Steifigkeitsmatrix benötigt. Damit können sowohl Materialnichtlinearitäten als auch Kontakt geeignet erfasst und damit die Kraft-Zeit-Funktion des Einschlages ermittelt werden. Auch bei extrem hochdynamischen Vorgängen liefert diese Methode ein gutes Ergebnis. Es müssen dafür jedoch weit mehr Werkstoffdaten bekannt sein, um das nichtlineare elasto-plastische Materialverhalten mit Schädigungseffekten korrekt zu beschreiben. Die Schwierigkeiten der Werkstoffdatenbestimmung werden in den Grundlagen erläutert. / The presentation describes how to analyze the impact of an idealized fragment into a stell protective panel with different dynamic analysis methods. Two different commercial Finite Element codes are used for this: a.) Creo Simulate: This code uses the method of modal superposition for analyzing the dynamic response of linear dynamic systems. Therefore, only modal damping and no contact can be used. The unknown force-vs.-time curve of the impact event cannot be computed, but must be assumed and applied as external force to the steel protective panel. As more dynamic the impact, as sooner the range of validity of the underlying linear model is left. b.) Abaqus/Explicit: This code uses a direct integration method for an incremental (step by step) solution of the underlying differential equation, which does not need a tangential stiffness matrix. In this way, matieral nonlinearities as well as contact can be obtained as one result of the FEM analysis. Even for extremely high-dynamic impacts, good results can be obtained. But, the nonlinear elasto-plastic material behavior with damage initiation and damage evolution must be characterized with a lot of effort. The principal difficulties of the material characterization are described.

Der Vortrag beschreibt wie sich mittels der unterschiedlichen Berechnungsverfahren zur Lösung dynamischer Strukturpobleme der Einschlag eines idealisierten Bruchstücks in eine Schutzwand berechnen lässt. Dies wird mittels zweier kommerzieller FEM-Programme beschrieben: a.) Creo Simulate nutzt zur Lösung die Methode der modalen Superposition, d.h., es können nur lineare dynamische Systeme mit rein modaler Dämpfung berechnet werden. Kontakt zwischen zwei Bauteilen lässt sich damit nicht erfassen. Die unbekannte Kraft-Zeit-Funktion des Einschlagvorganges muss also geeignet abgeschätzt und als äußere Last auf die Schutzwand aufgebracht werden. Je dynamischer der Einschlagvorgang, desto eher wird der Gültigkeitsbereich des zugrunde liegenden linearen Modells verlassen. b.) Abaqus/Explicit nutzt ein direktes Zeitintegrationsverfahren zur schrittweisen Lösung der zugrunde liegenden Differentialgleichung, die keine tangentiale Steifigkeitsmatrix benötigt. Damit können sowohl Materialnichtlinearitäten als auch Kontakt geeignet erfasst und damit die Kraft-Zeit-Funktion des Einschlages ermittelt werden. Auch bei extrem hochdynamischen Vorgängen liefert diese Methode ein gutes Ergebnis. Es müssen dafür jedoch weit mehr Werkstoffdaten bekannt sein, um das nichtlineare elasto-plastische Materialverhalten mit Schädigungseffekten korrekt zu beschreiben. Die Schwierigkeiten der Werkstoffdatenbestimmung werden in den Grundlagen erläutert. / The presentation describes how to analyze the impact of an idealized fragment into a stell protective panel with different dynamic analysis methods. Two different commercial Finite Element codes are used for this: a.) Creo Simulate: This code uses the method of modal superposition for analyzing the dynamic response of linear dynamic systems. Therefore, only modal damping and no contact can be used. The unknown force-vs.-time curve of the impact event cannot be computed, but must be assumed and applied as external force to the steel protective panel. As more dynamic the impact, as sooner the range of validity of the underlying linear model is left. b.) Abaqus/Explicit: This code uses a direct integration method for an incremental (step by step) solution of the underlying differential equation, which does not need a tangential stiffness matrix. In this way, matieral nonlinearities as well as contact can be obtained as one result of the FEM analysis. Even for extremely high-dynamic impacts, good results can be obtained. But, the nonlinear elasto-plastic material behavior with damage initiation and damage evolution must be characterized with a lot of effort. The principal difficulties of the material characterization are described.