Die bestimmung des Schwefels im Sprit nach der Verbrennungsmethode

Zusammenfassung Die Lampen-Methode von American Society of Testing Materials (A. S. T. M.) zur Bestimmung des Schwefelgehaltes in Erdölprodukten wurde für die Bestimmung von kleinen im Sprit als Verunreinigung vorkommenden Schwefelmengen modifiziert. Für die Bestimmung wurde eine Apparatur entworfen und ausgeführt, in der der Sprit in einem entschwefelten Luftstrom verbrannt und der schwefelenthaltende Teil der Verbrennungsgase quantitativ absorbiert wird. Der Aufbau und die Anwendung der Apparatur werden eingehend beschrieben. Mit der Apparatur können gleichzeitig drei Doppelbestimmungen durchgeführt werden.Der zu Schwefeldioxyd oxydierte Schwefel wird in ammoniakalischer Wasserstoffperoxydlösung absorbiert und der gebildete Sulfatschwefel in einer alkoholhaltigen Lösung als Benzidinsulfat gefällt. Die Benzidin- (Schwefel-) Menge wird spektrophotometrisch bei der Wellenlänge 250 mµ (2500 Å) bestimmt.Der totale Erfassungsbereich der Methode bei Verbrennung von etwa 20 g Sprit beträgt 0,015–6,0 mg Schwefel in 100 ml Sprit. Nach den durchgeführten Probebestimmungen bei Schwefelgehalten von 2,1 und 0,77 mg in 100 ml war die Streuung etwa 0,09 und der mittlere Fehler etwa 0,04. Bei den Schwefelgehalten unter 0,2 mg in 100 ml müssen die Resultate als halbquantitativ behandelt werden. Durch Vergrößerung der verbrannten Spritmenge ist es möglich, die Methode empfindlicher zu machen.Die Methode ist auch für die Bestimmung des Schwefelgehaltes in Methanol und anderen Alkoholen geeignet.     

Planning for multiple measurement channels in a continuous-state POMDP

Continuous-state partially observable Markov decision processes (POMDPs) are an intuitive choice of representation for many stochastic planning problems with a hidden state. We consider a continuous-state POMDPs with finite action and observation spaces, where the POMDP is parametrised by weighted sums of Gaussians, or Gaussian mixture models (GMMs). In particular, we study the problem of optimising the selection of measurement channel in such a framework. A new error bound for a point-based value iteration algorithm is derived, and a method for constructing a subset of belief states that attempts to reduce the error bound is implemented. In the experiments, applying continuous-state POMDPs for optimal selection of the measurement channel is demonstrated, and the performance of three GMM simplification methods is compared. Convergence of a point-based value iteration algorithm is investigated by considering various metrics for the obtained control policies.     

Energy-efficient control strategy for variable speed-driven parallel pumping systems

The article aims to find a solution for the energy efficiency improvements in variable speed-controlled parallel pumping systems with lesser initial data and without additional flow metering and start-up measurements. This paper introduces a new control strategy for variable speed-controlled parallel pumps based on flow rate estimation and pump operation analysis utilizing variable speed drives. The energy-saving potential of the new control strategy is studied with simulations and laboratory measurements. The energy consumption of the parallel pumps using the new control strategy is compared with the traditional rotational speed control strategy of parallel pumps. The benefit of the new control strategy is the opportunity to operate variable speed-controlled parallel pumps in a region which suggests improved energy efficiency and lower risk of mechanical failure of the controlled pumps compared with traditional control. The article concludes by discussing the implications of the findings for different applications and varying system conditions.     

Optimization issues of the broke management system in papermaking

This paper presents an optimization strategy for the design and operation of a broke management system in a papermaking process. A stochastic model based on a two-state Markov process is presented for the broke system and a multiobjective and bi-level stochastic optimization model is developed featuring (i) a multiobjective operational subproblem for the optimization of the broke dosage and (ii) a multiobjective design problem formulation. An efficient optimization strategy is proposed for the operational subproblem along with a simulation based Pareto optimal solution for the design problem, and illustrated with a detailed case study.     

Hydrolysis behaviour of crosslinked poly(ester anhydride) networks prepared from functionalised poly(ε-caprolactone) precursors

Biodegradable poly(ester anhydride) networks based on functionalised poly(ε-caprolactone) precursors with different hydrophobicities, molecular weights and architectures were synthesised. Networks that were prepared from the star-shaped precursors clearly showed higher gel contents and crosslinking densities than the networks that were prepared from the linear precursors. Functionalising with different alkenylsuccinic anhydrides and/or varying the molecular weight of the precursor, the thermal properties, surface hydrophobicity and erosion of the crosslinked networks were widely tailored. The dissolution behaviour of the networks changed dramatically as the molecular weight of the precursor increased from 2000 to 4000 g/mol or the alkenyl chain of the alkenylsuccinic anhydride increased from 8 to 18 carbons. The networks that were prepared from the lower molecular weight precursors, without an alkenyl chain or with an 8 carbon alkenyl chain, lost their mass in a few days, whereas the networks that were prepared from higher molecular weight precursors or contained a hydrophobic 18 carbon alkenyl chain did not show any mass loss over a period of 8 weeks.     

New Technologies in Ammonia Refrigerating and Air-Conditioning Systems

This review paper describes a brief historic perspective of transition from natural refrigerants to synthetic and now back to natural refrigerants. The thermodynamic, physical and safety properties of ammonia are presented. The advantages and disadvantages of ammonia refrigerant are discussed. The heat exchanger technology has seen introduction of compact and efficient equipment both in shell and tube and plate technologies. The micro-channel exchangers are being introduced in the automotive industry and it could soon enter into the commercial and industrial refrigeration markets. Compact heat exchangers are of interest due to their low refrigerant inventory features. A new electromotor technology is being developed now, using encapsulated copper windings or aluminum windings for semi-hermetic ammonia compressors. A hermetic scroll compressor for ammonia small refrigerating systems is also in the offing. In the last several years large numbers of air conditioning systems with ammonia chillers have been installed in commercial and public facilities. In large industrial systems where there is a need for low evaporating temperatures, Ammonia/Carbon Dioxide cascade systems are being proposed and installed.     

Moderate energy restriction with high protein diet results in healthier outcome in women

Background

Intense exercise induces increased blood neutrophil counts and decreased lymphocyte counts, and leads to inflammation and immunosuppression. It was previously reported that cystine and theanine (CT) supplementation by long-distance runners before a training camp suppressed the changes of these blood parameters observed in un-supplemented control subjects after the camp. The purpose of the present study was to determine the effects of CT supplementation on the inflammatory response and immune state before and after intense endurance exercise in long-distance runners at a training camp.

Methods

Sixteen long-distance runners were allocated to one of two groups given CT supplements (700 mg cystine + 280 mg theanine daily) or placebo (8 in each group) for 7 days prior to and during a 9-day training camp. Daily run training averaged 19.9 km/day prior to the camp and 28.6 km/day during the camp. On the initial and final days of the camp, blood samples were collected before and after 15 km morning interval running workouts (1000 m × 15 times) and analyzed for neutrophil and lymphocyte counts and myoglobin.

Results

The relative change in exercise-induced blood neutrophil count (% of pre-exercise values) was significantly lower in the CT group than in the placebo group (163.3 ± 43.2% vs. 200.4 ± 19.6%, p = 0.044) on the initial day of camp, but not on the last day. The decline in lymphocyte count (% of pre-exercise values) was significantly less in the CT group than in the placebo group (60.2 ± 19.2% vs. 36.2 ± 12.0%, p = 0.010) on the initial day of camp, but not on the last day. In blood myoglobin, there was a trend toward lower % of pre-exercise values in the CT group (p < 0.09) on both measurement days.

Conclusion

CT supplementation significantly attenuated the increase in neutrophil count and the reduction in lymphocyte count induced by intense endurance exercise. These results suggest that CT supplementation may suppress the exercise-induced fluctuation of the blood immunocompetent cells and may help to reduce the alteration of the immune state.     

Infrared laser ablation atmospheric pressure photoionization mass spectrometry

In this paper we introduce laser ablation atmospheric pressure photoionization (LAAPPI), a novel atmospheric pressure ion source for mass spectrometry. In LAAPPI the analytes are ablated from water-rich solid samples or from aqueous solutions with an infrared (IR) laser running at 2.94 μm wavelength. Approximately 12 mm above the sample surface, the ablation plume is intercepted with an orthogonal hot solvent (e.g., toluene or anisole) jet, which is generated by a heated nebulizer microchip and directed toward the mass spectrometer inlet. The ablated analytes are desolvated and ionized in the gas-phase by atmospheric pressure photoionization using a 10 eV vacuum ultraviolet krypton discharge lamp. The effect of operational parameters and spray solvent on the performance of LAAPPI is studied. LAAPPI offers ~300 μm lateral resolution comparable to, e.g., matrix-assisted laser desorption ionization. In addition to polar compounds, LAAPPI efficiently ionizes neutral and nonpolar compounds. The bioanalytical application of the method is demonstrated by the direct LAAPPI analysis of rat brain tissue sections and sour orange (Citrus aurantium) leaves.     

Polymeric dual-slab waveguide interferometer for biochemical sensing applications

A polymer based dual-slab waveguide Young's interferometer was demonstrated for biochemical sensing. Evanescent field is utilized for probing the binding events of biomolecules on the waveguide surface. Refractive index sensing in analyte and protein adsorption on the sensing surface were investigated with glucose de-ionized water solution and bovine serum albumin, immunoglobulin G solutions in phosphate buffered saline buffer. A detection limit of 10(-5) RIU and 4 pg/mm(2) was achieved for homogeneous and surface sensing, respectively. Also, the influence of water absorption inside the polymeric device on the measurement stability was evaluated. The results indicate that the waveguide polymer sensor fabricated with the spin coating technique can achieve a satisfactory sensitivity for homogeneous refractive index sensing and, as well, for monitoring molecular binding events on the surface.