Experience with model-based performance, reliability, and adaptability assessment of a complex industrial architecture

In this paper, we report on our experience with the application of validated models to assess performance, reliability, and adaptability of a complex mission critical system that is being developed to dynamically monitor and control the position of an oil-drilling platform. We present real-time modeling results that show that all tasks are schedulable. We performed stochastic analysis of the distribution of task execution time as a function of the number of system interfaces. We report on the variability of task execution times for the expected system configurations. In addition, we have executed a system library for an important task inside the performance model simulator. We report on the measured algorithm convergence as a function of the number of vessel thrusters. We have also studied the system architecture adaptability by comparing the documented system architecture and the implemented source code. We report on the adaptability findings and the recommendations we were able to provide to the system’s architect. Finally, we have developed models of hardware and software reliability. We report on hardware and software reliability results based on the evaluation of the system architecture.     

Volatilization of hydrogen sulfide from a quiescent surface

Air-water mass transfer of hydrogen sulfide from a shallow tank with a quiescent surface under the influence of weak wind stress on the water surface was studied numerically using a two-dimensional model. The flow field in the tank was investigated using a computational code based on a finite volume, which is used to numerically solve momentum, mass and continuity conservation equations. The results show that water phase flow field is strongly dependent on the wind-induced surface velocity and the aspect ratio of the tank. Based on the numerical study, the liquid-side mass transfer coefficient is correlated with Reynolds number (R(e)), tank aspect ratio (AR) and Schmidt number (S(c)). Overall mass transfer coefficient (K(L)) values extend further downstream as the R(e) number increases.     

Adsorption of lead and copper on bentonite and grapeseed activated carbon in single- and binary-ion systems

In this study, bentonite originating from Turkey (Eski?ehir province) and activated carbon obtained from grapeseed were used as adsorbents for the removal of lead (Pb²⁺) and copper (Cu²⁺) ions from aqueous solutions. Experiments were performed in single- and binary-ion systems at constant temperature of 298 K and pH value of 5. In order to describe the adsorption mechanism Langmuir, Freundlich and Temkin isotherms were used. The total adsorption capacity values of adsorbents were compared. It was observed that the total adsorption capacity values were changed depending on the type of adsorbent used, type of metal ion and interaction between metal ions.     

Untersuchungen zum Transfer pharmakologisch wirksamer Substanzen aus der Nutztierhaltung in Porree und Weißkohl

Investigation on the transfer of pharmacologically active substances used in animal husbandry into leek and cabbage. The potential of leek and cabbage for uptake of highly prescribed veterinary drugs (antibiotics) was tested in hydroponically grown plants. For this purpose the antibiotics sulfadiazine (SFD), enrofloxacine (ENR), tetracycline (TC), chlortetracycline (CTC) and monensine (MON) were chosen. A further aim was to gain data on the situation of vegetables grown in agricultural practise with regard to antibiotic residues. The evident effects of the antibiotics on plants grown hydroponically (each antibiotic was administered at 5 μmol/l nutrient solution) were greatly different: With regard to leek there were no visible effects (MON, SFD), a weak bleaching of the younger leaf sections (CTC), and strong effects of ENR. The (phytotoxic) effects of antibiotics on cabbage were much more distinct. CTC caused a yellowing of the plant vasculature in cabbage. MON induced lesions on some leaves and finally led to leaf wilting. With administration of ENR a nearly complete bleaching of young leaves was observed. Using LC-MS/MS-methods (low-resolution and high-resolution MS) the administered antibiotics, as well as conversion products and metabolites, were separately identified and quantified in various organs of leek (roots, young and old sections of leaves) and cabbage (roots, stalks, young and old leaves). Depending on the type of antibiotic, vegetable species, and plant organ, the detected concentrations of antibiotic residues comprised several orders of magnitude ranging from μg/kg to mg/kg of fresh weight (fw). The highest concentrations of antibiotics were found in roots of both vegetable species: CTC and TC were detected at approximately 10 mg/kg fw in cabbage roots and at approximately 20 mg/kg fw in leek roots and ENR was determined at approximately 12 mg/kg fw in cabbage roots. Low amounts of ENR were metabolised to ciprofloxacine (CIP). ENR occurred at similar concentrations of approximately 7 mg/kg fw in roots and old leaves of cabbage, indicating a high transport rate of this antibiotic in the cabbage plant. In stalks, young and old leaves of cabbage and in young and old leaf sections of leek all administered antibiotics were detected. Within these antibiotics, ENR and CTC and their conversion products, e. g. demeclocycline (DMC) and TC, occurred at the highest concentrations. SFD and MON were found in considerably lower concentrations (<100 μg/kg fw). The results of our experiments in hydroponic cultures, using defined concentrations of antibiotics in the nutrient solution, evidently demonstrate that cabbage and leek have a very high potential for uptake of a number of veterinary antibiotic drugs, especially for tetracycline and ENR.     

COUPLED OPTIMIZATION IN STEADY-STATE THERMOELASTICITY

Necessary optimaliry conditions for a static optimization problem in thermoelasticity are derived by calculus of variations. Optimal boundary heat fluxes and surface tractions are then found by means of a numerical method of solution that utilizes the finite-element and conjugate-gradient methods. It is found that the coefficient of linear thermal expansion of the solid body serves as the coupling parameter, affecting the optimal temperature as well as the displacement fields, a property which is not seen in a classical analysis of steady-state thermoelasticity.     

Investigation of the rotary swaging and heat treatment on the behavior of W- and γ-phases in PM 92.5W–5Ni–2.5Fe–0.26Co heavy alloy

The effects of rotary swaging and different heat treatment procedures on the W- and γ-phases behavior of PM 92.5W–5Ni–2.5Fe (wt.%) heavy alloy microalloyed with cobalt have been studied. The investigation was performed on sintered and cold rotary swaged samples deformed with area reduction from 5 to 30%. One batch of swaged samples was annealed in vacuum at 1473 K for 7.2 ks and then furnace-cooled to the room temperature, whereas another batch of swaged samples was previously deformed 30% and strain aged in argon and nitrogen in the temperature range between 473 and 1123 K for 3.6 ks. Strengthening of W- and γ-phases was investigated by applying microhardness measurements. Effects of the degree of deformation, parameters of heat treatment and strain aging on microstructural changes have been studied. Mechanical properties, hardness and microhardness of phases as a function of the degree of deformation and heat treatment were analyzed by applying statistical modeling. A correlation between deformation behavior of phases, effect of heat treatment and alloy properties was also discussed.     

Determination of selected mycotoxins in mould cheeses with liquid chromatography coupled to tandem with mass spectrometry

A simple and feasible method is described for analysing nine mycotoxins in cheese matrix. The method involves liquid extraction followed by high performance liquid chromatographic separation and mass spectrometric detection of the analytes, and allows the determination of aflatoxins B1, B2, G1, G2 and M1, ochratoxin A, mycophenolic acid, penicillic acid and roquefortine C simultaneously. Average recoveries of the mycotoxins from spiked samples at concentration levels of 5-200 µg kg^-1 ranged from 96-143%. Within-day relative standard deviations at these concentration levels varied from 2.3-12.1%. The limit of quantification for aflatoxin M1 was 0.6 µg kg^-1 and for the other compounds 5 µg kg^-1. The method developed was applied for analysing these mycotoxins in blue and white mould cheeses purchased from Finnish supermarkets. Roquefortine C was detected in all of the blue mould cheese samples in concentrations of 0.8-12 mg kg^-1. One blue cheese contained also 0.3 mg kg^-1 mycophenolic acid. The other investigated mycotoxins were absent in the samples.     

Synovial-type (group II) phospholipase A2 human seminal plasma

Phospholipase A2 (PLA2) was analysed in seminal plasma of fertile, subfertile, and vasectomized men as well as in prostatic secretion and tissue. Immunological cross-reactivity was observed between synovial-type PLA2 antiserum and the enzyme present in seminal plasma. There was a highly significant correlation between the concentration of the synovial-type PLA2, as measured by a time-resolved fluoroimmunoassay and the catalytic activity of the PLA2. The results show that the PLA2 content in human seminal plasma is very high (approximately 1000 times of that present in blood plasma) and that the enzyme belongs to the synovial-type group II phospholipase A2. The results also indicate that the enzyme is secreted by the prostate.     

Acute toxicity removal in textile finishing wastewater by Fenton's oxidation, ozone and coagulation-flocculation processes

This study evaluates the effectiveness of Fenton's oxidation (FO) process and ozone (O3) oxidation compared with a coagulation-flocculation (CF) process to remove effluent toxicity as well as colour and COD from a textile industry wastewater. Daphnia magna was used to test acute toxicity in raw and pre-treated wastewater. The operational parameters for each process were determined on the basis of complete toxicity removal. The FO process removed COD at a higher rate (59%) than O3 (33%) while colour removal was similar (89% and 91%, respectively). The CF process removed both COD and colour at rates similar to the FO process. A colour range of 150-250 platin-cobalt (Pt-Co) unit was assessed for toxicity.