Effects on DC SQUID characteristics of damping of input coil resonances

The possibility of improving dc SQUID performance by damping the input circuit resonances caused by parasitic capacitances is studied experimentally. A high-quality dc SQUID was coupled to a first-order axial gradiometer built for neuromagnetic research, and a resistor-capacitor shunt was connected in parallel with the input coil of the SQUID. Ten differentRC shunts were studied with the SQUID operating in a flux-locked loop, carefully shielded against external disturbances. It was found that increasing the shunt resistance resulted in smoother flux-voltage characteristics and smaller noise. At best, the minimum obtainable equivalent flux noise level was one-fourth that for the unshunted SQUID. The noise level is a function of the shunt resistanceR _s only, except for shunt capacitance values bringing the low-frequency resonance of the input coil close to the flux modulation frequency. At a constant bias current level, where the amplitude of the flux-voltage characteristics is at maximum, the equivalent flux noise varies asR _s ^/–0.7 . The results agree reasonably well with recently published predictions based on numerical simulations where the whole input circuit with parasitic capacitances was taken into account.     

Bayesian learning of graphical vector autoregressions with unequal lag-lengths

Graphical modelling strategies have been recently discovered as a versatile tool for analyzing multivariate stochastic processes. Vector autoregressive processes can be structurally represented by mixed graphs having both directed and undirected edges between the variables representing process components. To allow for more expressive vector autoregressive structures, we consider models with separate time dynamics for each directed edge and non-decomposable graph topologies for the undirected part of the mixed graph.Contrary to static graphical models, the number of possible mixed graphs is extremely large even for small systems, and consequently, standard Bayesian computation based on Markov chain Monte Carlo is not in practice a feasible alternative for model learning. To obtain a numerically efficient approach we utilize a recent Bayesian information theoretic criterion for model learning, which has attractive properties when the potential model complexity is large relative to the size of the observed data set. The performance of our method is illustrated by analyzing both simulated and real data sets. Our simulation experiments demonstrate the gains in predictive accuracy which can obtained by considering structural learning of vector autoregressive processes instead of unstructured models. The analysis of the real data also shows that the understanding of the dynamics of a multivariate process can be improved significantly by considering more flexible model classes.     

Using dataflow in a system of multiple single board computers

The concept of dataflow is usually limited to totally new computer structures. This paper discusses the simulation of dataflow in a symmetric system of standard microcomputer modules. The approach has advantages in that the parallelism of the computation can be expressed and handled in a natural way. The simulation of the dataflow semantics takes, however, hundreds of machine instructions for each actor execution and quite long actors are needed to keep the overhead low. The implementation of a dataflow computation using the adaptive trapezoid method for numerical integration is discussed. In this computation the total estimated overhead is less than 10 per cent.     

Studies on blends of a thermotropic liquid crystalline polymer and polybutylene terephthalate

Summary Structure-property relationships of blends of a thermotropic polyester-type main-chain LCP and polybutylene terephthalate (PBT) were investigated. LCP was melt blended with three different PBTs and the blends were processed by injection moulding or extrusion. Mechanical and thermal properties of the blends were determined and the blend structure was characterized by scanning electron microscopy (SEM). LCP acted as mechanical reinforcement for PBT and improved also its dimensional and thermal stability. The stiffness of PBT increased with increasing LCP content, but at the same time the blends became more brittle. In extrusion the orientation of LCP phases could be further enhanced by additional drawing, which led to significant improvements in strength and stiffness at LCP contents of 20–30 wt.-%.     

State‐of‐the‐Art of Friction Stir Processing

The aim of this study is to present an overall view of friction stir processing (FSP), including the method, the state‐of‐the‐art regarding current studies, and possible applications. FSP is a solid‐state thermo‐mechanical processing method. It can be used to produce defect‐free, recrystallized, homogeneous, fine grained microstructures. Structures can be processed at specific locations, through‐section or to a desired depth, or entirely. The benefits obtained with FSP include elimination of casting defects and refinement of microstructures resulting in improved strength, ductility, resistance to corrosion and fatigue, and formability (including high strain rate superplasticity). Alsosurface composites can be produced by FSP.     

Additive Benefits of Radium-223 Dichloride and Bortezomib Combination in a Systemic Multiple Myeloma Mouse Model

Osteolytic bone disease is a hallmark of multiple myeloma (MM) mediated by MM cell proliferation, increased osteoclast activity, and suppressed osteoblast function. The proteasome inhibitor bortezomib targets MM cells and improves bone health in MM patients. Radium-223 dichloride (radium-223), the first targeted alpha therapy approved, specifically targets bone metastases, where it disrupts the activity of both tumor cells and tumor-supporting bone cells in mouse models of breast and prostate cancer bone metastasis. We hypothesized that radium-223 and bortezomib combination treatment would have additive effects on MM. In vitro experiments revealed that the combination treatment inhibited MM cell proliferation and demonstrated additive efficacy. In the systemic, syngeneic 5TGM1 mouse MM model, both bortezomib and radium-223 decreased the osteolytic lesion area, and their combination was more effective than either monotherapy alone. Bortezomib decreased the number of osteoclasts at the tumor–bone interface, and the combination therapy resulted in almost complete eradication of osteoclasts. Furthermore, the combination therapy improved the incorporation of radium-223 into MM-bearing bone. Importantly, the combination therapy decreased tumor burden and restored body weights in MM mice. These results suggest that the combination of radium-223 with bortezomib could constitute a novel, effective therapy for MM and, in particular, myeloma bone disease.     

Occurrence and removal of organic pollutants in sewages and landfill leachates

Sewages of different composition and the effluents of four sewage treatment plants (STPs), plus sewage sludges were analysed for semivolatile organic priority pollutants. Furthermore, 11 landfill leachates were analysed to evaluate their contribution to sewage pollutants when co-treated. Bis(2-ethylhexyl) phthalate (DEHP) was the pollutant occurring at highest concentrations (up to 122 microg/l) and it was present in all sewages and leachates; concentrations of other phthalates were usually below 17 microg/l. Some polycyclic aromatic hydrocarbons (PAH) (<1 microg/l) and 2,6-dinitrotoluene (< or =5.9 microg/l) were also present in many of the sewages and leachates. Phthalates were present in STP effluents in low concentrations (<8 microg/l), while PAHs were usually not present. DEHP concentrations were at the same level in the sewage consisting of household wastewater and stormwater runoff and the sewages also including industrial discharges and landfill leachates, while PAHs were present in sewages containing industrial discharges. Leachate contribution to the total pollutant load to the STP was less than 1%. Sorption of DEHP to different particle size fractions in sewage was studied by serial membrane filtration. Most of the DEHP (71-84%) was attached to the particles 0.1-41 microm in size, and approximately 10-27% of the DEHP was sorbed on particles larger than 41 microm. Less than 6% of the DEHP was in the fraction below 0.1 microm and readily available for microbial degradation.     

Fatty acids of a whitefish (Coregonus albula) flesh lipids

Using gas chromatographic-mass spectrometric methods 50 fatty acid components of the flesh lipids of a fresh-water whitefish have been examined in detail. The total lipids represented, on average, 3.0% of the wet weight of whitefish fillets. Saturated, monoenoic and polyenoic fatty acids were present in proportions of 31.4, 22.4 and 44.2%, respectively. About half of the total saturated acids was composed of palmitic acid (16:0, 16.1 %), which is generally abundant in fish lipids. The proportion of saturated iso- and anteiso-acids was 2.9%. The major monoenoic acid was oleic acid (18:1,ω9 10.6%), whereas the monoenoic C₂₀-acids were present only in minor amounts and the monenoic C₂₂-acids were not detected at all. The polyenoic fatty acids were predominantly of ω3 series with docosahexaenoic (22:6ω3, 9.4%) and cicosapentaenoic (20:5ω3, 7.7%) acids as the major components. Linoleic (18:2ω6), linolenic (18:3ω3), octadecatetraenoic (18:4ω3) and arachidonic (20:4ω6) acids were also present in remarkable proportions each amounting to about 4.5% of the total fatty acids.     

High-Pressure Gelatinization of Barley Starch at Low Moisture Levels and Elevated Temperature

High-pressure gelatinization of barley starch at low water contents and at elevated temperature was performed in a differential scanning calorimeter equipped with a pressure chamber. Microscopic examination of the samples showed complete loss of birefringence and rupture of granular structure in most samples. The results indicated that enthalpy levels much higher than those in high-moisture gelatinization are needed to attain proper gelatinization and plastification of starch at low water contents.