In this thesis, fluid flow and solute transport in heterogeneous aquifers and particularly in frac-tured rock have been investigated using Lagrangian Stochastic Advective-Reaction (LaSAR) framework. The heterogeneity of the aquifer structure or fracture configuration, as well as the various reaction/retention processes have been considered in the modelling approach. Advection and retention processes are considered to be the dominant transport processes. Monte-Carlo simulation results for transport of nonreactive tracers in 2D generic heterogeneous aquifers indicate that the travel time τ can be well approximated by a lognormal distribution up to a relative high degree of heterogeneity of the aquifers. Comparison between the Monte-Carlo simulation results and the results of first-order approximation reveals that the analytical solutions of the statistical moments of τ are valid only when the variability of the aquifer properties is small. For reactive tracers, Monte-Carlo simulations have been conducted by accounting for spatial variability of both hydraulic conductivity and one sorption parameter simultaneously. The simulation results indicate that the reaction flow path μ is a nonlinear function of distance for shorter distance, linear function for longer distance, and also that μ and τ are well correlated over the considered parameter range. The parameter β, which is purely determined by the flow condi-tions, quantifies the hydrodynamic control of retention processes for transport of tracers in frac-tures. Numerical simulations have been performed to study the statistical properties of the pa-rameter β, travel time τ and flow rate Q in a single heterogeneous fracture and in a sequence of fractures. The results of Monte-Carlo simulations indicate that the parameter β and τ are corre-lated with a power-law relationship β ∼ τm. The correlation between β and the flow rate Q have also been studied and an inverse power-law relationship β ∼ Q-m is proposed. The establishment of these relationships provides a link between the parameter β and measurable parameters τ (or Q). The LaSAR approach has been applied for prediction, evaluation and interpretation of the results of a number of tracer tests (TRUE-1, TRUE Block Scale and TRUE Block Scale Continuation) conducted by SKB at the Äspö site for tracer transport in fractures. The breakthrough curves may be predicted reasonably well, provided that the retention parameters, boundary conditions and hydraulic properties of the domain are given. The evaluation of TRUE tests indicates that the retention occurs mainly in the rim zone on site characterization time scales, while on the per-formance assessment time scale, diffusion and sorption in the unaltered rock matrix are likely to become dominant retention mechanisms. / QC 20100624

Ett undersöknings- och utvecklingsarbete för att lösa ett problem med att dränkbara pumpar i ett vattenavrinningssystem gick sönder med perioder på två år i genomsnitt, utfördes i samarbete med Cementa AB i Skövde. Orsak till pumpars haveri söktes och fanns vara bristande rutiner och kunskap om det underhåll pumparna krävde. För att lösa detta problem utvecklades riktlinjer för nyinköp av torruppställda pumpar för att möjliggöra kontinuerligt underhåll. Då möjligheter för placering av torruppställd pump saknades utvecklades ett pumpfundament för placering av torruppställd pump. Krav för utvecklingsarbetet togs fram i samarbete med Cementas underhållsavdelning och teoretisk dimensionering av dränkbara länspumpars dåvarande volymflödeskapacitet utfördes. Krav utvärderades och viktades med hjälp av parvis jämförelse. Dimensionering och kontroll av hållfasthet för utvecklat pumpfundamentet utfördes med hjälp av Finita Element Analyser i programvaran Pro/Engineer Creo 1.0 Mechanica. Kontroll av hållfasthet i infästning av pumpfundamentet samt svetsfogar utfördes analytiskt. Arbetet resulterade i en rekommendation till Cementa AB i Skövde att ta in offerter på nya torruppställda pumpar med hjälp av utvecklade riktlinjer och att tillverka det pumpfundament som tagits fram inom ramen för examensarbetet, för att placera nya pumpar på. Att noggrant följa de underhållsinstruktioner som pumpar har och att underlätta för personal att utföra detta underhåll ansågs kunna bidra till att pumpar skulle få en längre och mer ekonomisk livslängd. / A development project to solve problems with why submersible pumps in a run-off system broke down with periods of two years, on average, was performed in collaboration with Cementa AB in Skövde. Reason for the pumps breakdowns was searched and found to be inadequate procedures and missing knowledge of the maintenance required on the pumps. To solve this problem, guidelines for the purchase of new dry pit pumps were developed to allow for continuous maintenance. As the possibilities of placing a dry well pump did not exist at Cementa, a pump foundation was developed. Requirements for the development work were produced in cooperation with Cementas maintenance department and theoretical dimensioning of the submersible bilge pumps volume flow capacity was performed. Requirements were evaluated and weighted using Pairwise comparison. The design and control of the strength of the developed pump foundation was performed using finite element analysis in the software Pro/Engineer Creo 1.0 Mechanica. Controls of the strength of the attachment of the pump foundation and welds were performed analytically. The work resulted in a recommendation to Cementa AB in Skövde to bring in quotes on the new dry-pit pumps using the developed guidelines and to manufacture the pump foundation developed within the framework of the thesis. Cementa was also recommended to carefully follow the maintenance instructions for pumps and make it easier for staff to perform this maintenance. This was recommended to ensure that new pumps would have a longer and more economical lifetime.

Blends of poly butylene terephthalate (PBT) and polycarbonate (PC) form a very important class of commercial blends in numerous applications requiring materials with good chemical resistance, impact resistance even at low temperatures, and aesthetic and flow characteristics. PC and PBT are usually blended in a twin screw extruder (TSE). Product melt volume flow rate (MVR) is a property used to monitor product quality while blending the PC/PBT in a twin screw extruder. It is usually measured off line in a quality control laboratory using extrusion plastometer on samples collected discretely during the compounding operation. Typically a target value representing the desired value of the quality characteristics for an in-control process, along with upper and lower control limits are specified. As long as the MVR measurement is within the control limits, the sample is approved and the whole compounded blend is assumed to meet the specification. Otherwise, the blend is rejected. Because of infrequent discrete sampling, corrective actions are usually applied with delay, thus resulting in wasted material. It is important that the produced PC/PBT blend pellets have consistent properties. Variability and fault usually arise from three sources: human errors, feed material variability, and machine operation (i.e. steady state variation). Among these, the latter two are the major ones affecting product quality. The resulting variation in resin properties contributes to increased waste products, larger production cost and dissatisfied customers. Motivated by this, the objective of this project was to study the compounding operation of PC/PBT blend in a twin screw extruder and to develop a feasible methodology that can be applied on-line for monitoring properties of blends on industrial compounding operations employing available extruder input and output variables such as screw speed, material flow rate, die pressure and torque. To achieve this objective, a physics-based model for a twin screw extruder along with a MVR model were developed, examined and adapted for this study, and verified through designed experiments. This dynamic model for a TSE captures the important dynamics, and relates measurable process variables (screw speed, torque, feed rates, pressure etc.) to ones that are not being measured (material holdups and compositions at the partially and filled section along a TSE barrel). This model also provides product quality sensors or inferential estimation techniques for prediction of viscosity and accordingly MVR. The usefulness of the model for inferential MVR sensing and fault diagnosis was demonstrated on experiments performed on a 58 mm co-rotating twin-screw extruder for an industrial compounding operation at a SABIC Innovative Plastics plant involving polycarbonate – poly butylene terephthalate blends. The results showed that the model has the capability of identifying faults (i.e., process deviation from the nominal conditions) in polymer compounding operations with the twin screw extruder. For instance, the die pressure exhibited a change as a function of changes in raw materials and feed composition of PC and PBT. In the presence of deviations from nominal conditions, the die pressure parameters are updated. These die pressure model parameters were identified and updated using the recursive parameter estimation method. The recursive identification of the die pressure parameters was able to capture very well the effects of changes in raw material and/or composition on the die pressure. In addition, the developed MVR model showed a good ability in monitoring product MVR on-line and inferentially from output process variables such as die pressure which enables quick quality control to maintain products within specification limits and to minimize waste production.

In this work, the compounding of polycarbonate (PC) / poly-butylene terephthalate (PBT) blends was studied for the purpose of improving quality of products with reduced wastage and finally to satisfaction of end users. The effect of material rheological characteristics and processing conditions on compounding of PC /PBT was investigated through statistical experiments carried out on a 58 mm twin-screw extruder at SABIC Innovative Plastics Limited (formerly GE Plastics Limited) in Cobourg, Ontario. Melt Volume-Flow Rate (MVR) is the most commonly used property to monitor the quality of products of PC/PBT blends. The MVR was studied with different sampling times and correlations between product properties (melt flow) and processing conditions (screw speed, flow rates) were discussed. The rheological behavior of PC/PBT blends was investigated by dynamic and capillary rheometers. The effects of processing conditions (screw speed, feed rate) on viscosity were measured and it was found that the Cox-Merz rule is not valid for PC/PBT blends. The change of morphology of PC/PBT blends was observed under a scanning electron microscope (SEM) by using different types of samples. Those samples were (i) PC/PBT blends pellets, (ii) PC/PBT blend samples, but collected after completing the rheological tests in the parallel plate rheometer, and (iii) PC/PBT blend samples, but collected after completing the rheological tests in the capillary rheometer. There was evidence that the samples collected after completing the tests in the parallel and capillary rheometer might be degraded due to temperature and time.

Blends of poly butylene terephthalate (PBT) and polycarbonate (PC) form a very important class of commercial blends in numerous applications requiring materials with good chemical resistance, impact resistance even at low temperatures, and aesthetic and flow characteristics. PC and PBT are usually blended in a twin screw extruder (TSE). Product melt volume flow rate (MVR) is a property used to monitor product quality while blending the PC/PBT in a twin screw extruder. It is usually measured off line in a quality control laboratory using extrusion plastometer on samples collected discretely during the compounding operation. Typically a target value representing the desired value of the quality characteristics for an in-control process, along with upper and lower control limits are specified. As long as the MVR measurement is within the control limits, the sample is approved and the whole compounded blend is assumed to meet the specification. Otherwise, the blend is rejected. Because of infrequent discrete sampling, corrective actions are usually applied with delay, thus resulting in wasted material. It is important that the produced PC/PBT blend pellets have consistent properties. Variability and fault usually arise from three sources: human errors, feed material variability, and machine operation (i.e. steady state variation). Among these, the latter two are the major ones affecting product quality. The resulting variation in resin properties contributes to increased waste products, larger production cost and dissatisfied customers. Motivated by this, the objective of this project was to study the compounding operation of PC/PBT blend in a twin screw extruder and to develop a feasible methodology that can be applied on-line for monitoring properties of blends on industrial compounding operations employing available extruder input and output variables such as screw speed, material flow rate, die pressure and torque. To achieve this objective, a physics-based model for a twin screw extruder along with a MVR model were developed, examined and adapted for this study, and verified through designed experiments. This dynamic model for a TSE captures the important dynamics, and relates measurable process variables (screw speed, torque, feed rates, pressure etc.) to ones that are not being measured (material holdups and compositions at the partially and filled section along a TSE barrel). This model also provides product quality sensors or inferential estimation techniques for prediction of viscosity and accordingly MVR. The usefulness of the model for inferential MVR sensing and fault diagnosis was demonstrated on experiments performed on a 58 mm co-rotating twin-screw extruder for an industrial compounding operation at a SABIC Innovative Plastics plant involving polycarbonate – poly butylene terephthalate blends. The results showed that the model has the capability of identifying faults (i.e., process deviation from the nominal conditions) in polymer compounding operations with the twin screw extruder. For instance, the die pressure exhibited a change as a function of changes in raw materials and feed composition of PC and PBT. In the presence of deviations from nominal conditions, the die pressure parameters are updated. These die pressure model parameters were identified and updated using the recursive parameter estimation method. The recursive identification of the die pressure parameters was able to capture very well the effects of changes in raw material and/or composition on the die pressure. In addition, the developed MVR model showed a good ability in monitoring product MVR on-line and inferentially from output process variables such as die pressure which enables quick quality control to maintain products within specification limits and to minimize waste production.

In this work, the compounding of polycarbonate (PC) / poly-butylene terephthalate (PBT) blends was studied for the purpose of improving quality of products with reduced wastage and finally to satisfaction of end users. The effect of material rheological characteristics and processing conditions on compounding of PC /PBT was investigated through statistical experiments carried out on a 58 mm twin-screw extruder at SABIC Innovative Plastics Limited (formerly GE Plastics Limited) in Cobourg, Ontario. Melt Volume-Flow Rate (MVR) is the most commonly used property to monitor the quality of products of PC/PBT blends. The MVR was studied with different sampling times and correlations between product properties (melt flow) and processing conditions (screw speed, flow rates) were discussed. The rheological behavior of PC/PBT blends was investigated by dynamic and capillary rheometers. The effects of processing conditions (screw speed, feed rate) on viscosity were measured and it was found that the Cox-Merz rule is not valid for PC/PBT blends. The change of morphology of PC/PBT blends was observed under a scanning electron microscope (SEM) by using different types of samples. Those samples were (i) PC/PBT blends pellets, (ii) PC/PBT blend samples, but collected after completing the rheological tests in the parallel plate rheometer, and (iii) PC/PBT blend samples, but collected after completing the rheological tests in the capillary rheometer. There was evidence that the samples collected after completing the tests in the parallel and capillary rheometer might be degraded due to temperature and time.

Currently 884 million people worldwide are living without access to an improved source of drinking water (WHO/UNICEF, 2011). Piped-water on premises is the ultimate goal of World Health Organization (WHO) due to the ability to treat all of the water and distribute it safely in pressurized pipes. However, Household Water Treatment and Safe Storage (HWTS) is an option for improving the quality of drinking water where that infrastructure is not yet developed, especially where there is a risk of recontamination between point of collection and point of use (Clasen, 2006). This study analyzed one such HWTS, the ceramic pot water filter. The study compared the hydraulic properties of the FilterPure (FP) and Potters for Peace (PFP) ceramic pot filters through a thirteen-month field study in the Dominican Republic and laboratory studies at the University of South Florida. In the field study 55 filters were tested for first hour flow rate and hydraulic conductivity. Eight first hour flow rate tests were conducted in the field on one month intervals during months 7- 13. FP filters had an average first hour flow rate of 553 ml/hr and PFP Filters had a first hour flow rate of 395 ml/hr. No significant change in first hour flow rate was observed over time in FP filters. PFP experienced an average increase of 31 ml/hr per month during the seven-month testing period. Falling head tests were conducted on four filters in the laboratory and the flow rate was modeled to determine hydraulic conductivity. Hydraulic conductivity values for FP filters ranged from k = 0.0495 - 0.0831 cm/hr and for PFP filters ranged from k = 0.0136 - 0.0389 cm/hr. Eight out of 29 (26%) Potters for Peace filters in the field had first hour flow rates of less than 250 ml/hr by month nine of the study and had to be replaced and removed from the study. In total 24 of 55 (44%) filters (8 FP and 16 PFP) had to be removed from the study due to several reasons discussed in this thesis.

Darbe nagrinėta Šalčios upė, jos tyrimui buvo pasirinkti 24 vandens mėginių ėmimo taškai, kuriuose nustatytos tokių biogeninių medžiagų koncentracijos: amonio azoto, nitratų azoto, nitritų azoto, pH ir bendrojo fosforo. Pagal gautus duomenis iš hidrometeorologijos tarnybos nustatyta debito priklausomybė nuo klimato veiksnių. Atsižvelgiant į fizines-geografines sąlygas ir įvertinus maksimalius metinius kritulius bei vienos liūties kritulius, nustatytas susidarančio nuotėkio pobūdis. Išanalizavus gautus natūrinių tyrimų rezultatus, nustatyti veiksniai, lemiantys didžiausią upės vandens taršą. Pagal gautus duomenis nustatyta upės ekologinė būklė. Darbą sudaro 6 dalys: įvadas, mokslinės literatūros apžvalga, tyrimo objektas ir metodika, tyrimų rezultatai, išvados, literatūra. Darbo apimtis: 69 p. teksto be priedų, 34 iliustracijos, 9 lentelės, 65 literatūros šaltiniai. / The scientific literature related to the issue and research methodology is discribed in this master work. In the work was analyzed Šalčia’s River, there were selected 24 sampling points where was detected concentrations of these nutrients: ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, pH, and total phosphorus. According to the data obtained from the Hydrometeorological Service there were determined flow dependence on climatic factors. In view of the physical-geographical conditions and the evaluation of the maximum annual rainfall and the rainfall of a storm there were generated runoff patterns. The analysis of the results obtained during the experimental helped to determine the factors leading to maximum river water pollution. According to the data obtained there was found ecological status of the river. The work consists of six parts: introduction, literature review, research and methodology, results, conclusions and references. Work size: 69 p. text, 34 figures, 9 tables, 65 references.

The work started with the clinical observations in patients working in buildings with indoor air problems. Signs of seborrhoeic dermatitis, erythematous facial skin conditions and itching conditions on the trunk were noted. Another point of departure was the attribution of facial skin symptoms to VDT work by patients. A questionnaire-based prevalence study of symptoms compatible with the Sick Building Syndrome (SBS) and facial skin symptoms in 4,943 office workers formed the basis for two case referent studies, one focusing on SBS, the other on facial skin symptoms in VDT workers. The prevalence of SBS was three times higher in women than men. The prevalence was higher in young persons and in atopies. Facial skin symptoms showed the same pattern. Psychosocial work load, paper and VDT work were also risk indicators for SBS and for skin symptoms. The symptom excess in women was analyzed with reference to differences in biological or acquired risks and different illness and reporting behaviour. In spite of inequalities in social conditions at home and at work and differences in physical working conditions, these differences could only explain a small part of the gender difference. The odds ratio for SBS in women was lowered from 3.4 in the crude analysis to 3.0 in the multivariate analysis. Effect modification was in most cases stronger in men and the clinical validation of the questionnaire refuted the hypothesis that women over-report symptoms. The results indicate that the gender difference in symptom prevalence is part of a general pattem common to psychosomatic illnesses. In the case referent study of SBS, atopy, psychosocial work load, buildings built or renovated after 1977, the presence of photocopiers and a low outdoor air flow rate were risk indicators. The association between air quality and the occurrence of SBS symptoms was demonstrated by a flow-response relation between the outdoor air flow rate and SBS symptoms. In the case referent study of skin symptoms in VDT work, psychosocial work load, electric background fields, the presence of fluorescent lights with plastic shields and low cleaning frequency were risk indicators. The clinical findings in the two case groups and their referents supported the applied relevance of the studies. Compared with the referents, the SBS cases had more work- related facial erythema, seborriioeic dermatitis and general pruritus, while skin symptom cases, had more work-related facial erythema than their referents. The results show that SBS symptoms and facial skin symptoms have a multifactorial background with constitutional, psychosocial and physical risk indicators. As the indoor air quality is a determinant of SBS symptoms, and the building itself is but one source of indoor air pollution, it is suggested that the name Sick Building Syndrome (SBS) be replaced by Indoor Air Syndrome (IAS). / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1994, härtill 5 uppsatser.</p> / digitalisering@umu

Thesis (Ph.D.); Submitted to Iowa State Univ., Ames, IA (US); 19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2134" Meera Jay Desai. US Department of Energy 12/19/2004. Report is also available in paper and microfiche from NTIS.