“Aerosoltrap”—A New Device for Inertial Dust Separation: CFD Simulations with Experimental Validation

Inertial separation of dust from air and gas streams using settling or baffle chambers is simple and cost effective. In order to increase the effectiveness of a single chamber, AerosolTrap has been developed. This new device uses four chambers in series, stacked on top of each other. The aim of the present study is to examine the performance of AerosolTrap and investigate if computational fluid dynamics (CFD) simulations can be used as a tool to optimize its geometry. Simulations and validating laboratory experiments have been performed using different flows and different mix of particles. This article describes the methodology used and presents results showing that CFD simulations predict the general characteristics of the AerosolTrap well but underestimate the separation coefficient slightly.     

Film-forming capability in rough surface EHL investigated using contact resistance

Highly loaded machine elements such as gears and cams have a non-smooth surface topography that is created during manufacturing. It is well known that the film-building properties of such surfaces may be different from those that are perfectly smooth. The capability to form a separating film may also be altered in time due to run-in phenomena. In this study, a smooth steel ball was loaded against rough steel discs and run under pure rolling as well as sliding conditions. Several different steel surfaces were tested under nominal EHL conditions, where the contact was monitored by means of its electrical resistance and capacitance. Each surface was first run in for 15 min, followed by a sweep-in speed determining the lift-off curve. Electrical contact measurements were continuously conducted during run in as well as lift-off. Fully formulated gear oil and its base fluid were used as test lubricants. Results show that run in of a surface seems to be a competition between conformation of surface topography and tribofilm formation. At the tested conditions, the formation of a tribofilm is dependent on the initial surface topography and is created rapidly causing less metal–metal contact. This film also seems to effectively prohibit changes in surface topography causing less structural run in than expected.     

Enantiomeric Specificity in a Pheromone–Kairomone System of Two Threatened Saproxylic Beetles, Osmoderma eremita and Elater ferrugineus

The scarab beetle Osmoderma eremita and its larval predator, the click beetle Elater ferrugineus, are threatened saproxylic beetles regarded as indicators of the species-richness of insect fauna of hollow deciduous trees. Male O. eremita produce the pheromone (R)-(+)-γ-decalactone to attract conspecific females, and this compound is also utilized by E. ferrugineus as a kairomone, presumably for detection of tree hollows containing prey. We have investigated enantiomeric specificity to γ-decalactone in this pheromone–kairomone system by electrophysiological and field trapping experiments. In single-sensillum recordings from male and female O. eremita, which used the (R)-enantiomer and the racemic mixture of γ-decalactone as odor stimuli, numerous olfactory receptor neurons (ORNs) responding to both stimuli were found. No neurons responded preferentially to the racemic mixture, showing that these beetles seem to lack receptors specific for the (S)-enantiomer. The enantiomeric specificity of ORNs was confirmed by gas chromatography-linked single-sensillum recordings where the two enantiomers in a racemic mixture were separated on a chiral column. Furthermore, in field experiments that used the (R)-enantiomer and the racemic mixture as lures, the attraction of O. eremita females corresponded to the amount of (R)-enantiomer released from lures with the (S)-enantiomer displaying no antagonistic effects. Trap catch data also suggested that the (S)-enantiomer is not a behavioral antagonist for E. ferrugineus. The odor-based system can be highly efficient in attracting the larval predator where trap catch in 1 yr almost equaled the total number of specimens collected in Sweden until 1993. Our study shows that racemic γ-decalactone could be used for cost-effective monitoring of both beetles.     

Compensation Effect of Benzene Hydrogenation on Pt(111) and Pt(100) Analyzed by the Selective Energy Transfer Model

Kinetic measurements at low temperatures (310–360 K) using gas chromatography (GC) for benzene hydrogenation on Pt(100) and Pt(111) single crystal surfaces have been carried out at Torr pressures. These kinetic measurements demonstrated a linear compensation effect for the production of cyclohexane. A detailed application of the model of selective energy transfer to the experimentally obtained results yields the vibrational frequency of the adsorbate leading to reaction. This frequency is attributed to ring distortion modes. The vibrational frequency of the heat bath, or catalyst, is ascribed to a Pt-H mode. An approximate heat of adsorption of the reacting molecule is also calculated from the model.     

The analysis and occurrence of hydrazine toxins in fresh and processed false morel,Gyromitra esculenta

Summary Two methods for the extraction and determination of hydrazines in false morel,Gyromitra esculenta, were compared. Extraction under acid hydrolysis yielded much higher levels of the hydrazines, measured as monomethylhydrazine (MMH), than a direct solvent extraction. This shows that the greater part of the hydrazines in the false morel is chemically bound. Further studies are required to reveal the extent to which these stable hydrazine compounds are liberated in the human stomach after ingestion of false morels. The total amounts of MMH in Swedish fresh false morels varied from 40 to 150 mg/kg. Boiling the fungus in large amounts of water for 2 x 5 min effectively reduced the levels to 10% of the original amounts. After drying in the open air at room temperature for 3 months, as much as 30%-71 % of MMH remained in the fungus. These results suggest that the drying of false morels is an inadequate method of detoxication.

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Analyse und Vorkommen der Hydrazintoxine in frischen und eingedosten Lorcheln,Gyromitra esculenta

Zusammenfassung Zwei Methoden zur Extraktion und Bestimmung von Hydrazinen in der Frühjahrslorchel,Gyromitra esculenta, wurden miteinander verglichen. Die Extraktion unter sauren hydrolytischen Bedingungen ergibt viel mehr Hydrazine, bestimmt als Monomethylhydrazin (MMH), als durch eine direkte Lösungsmittelextraktion. Dieses Verhältnis zeigt, daß der größte Teil des Hydrazins in der Frühjahrslorchel chemisch gebunden ist. Weitere Untersuchungen sind nötig, um klarzulegen, ob größere Anteile dieser stabilen Verbindungen im Magen des Menschen nach dem Verzehr von Frühjahrslorcheln freigesetzt werden können. Die totale Menge von MMH in schwedischen frischen Frühjahrslorcheln variierte von 40 bis 150 mg/kg. Das Kochen der Pilze in großen Mengen Wasser für 2 x 5 min reduziert den Gehalt bis zu 10% der ursprünglichen Menge. Nach dem Trocknen an der Luft bei Zimmertemperatur während drei Monaten blieb etwa 30–71% von MMH in dem Pilz zurück. Diese Ergebnisse deuten daraufhin, daß das Trocknen von Frühjahrslorcheln eine ungenügende Methode zur Entfernung des Giftes ist.

     

Spatial analysis of diffusion tensor tractography statistics along the inferior fronto-occipital fasciculus with application in progressive supranuclear palsy

Background

The purpose of the study was to develop a method for analysis of diffusion parameters along white matter (WM) tracts, using spatial normalization based on anatomical landmarks, and to introduce the apparent area coefficient (AAC). The method’s applicability was tested in the inferior fronto-occipital fasciculus (IFO) in patients with progressive supranuclear palsy (PSP) and healthy controls (HCs).

Methods

A framework for analysis of diffusion parameters was developed. Spatial normalization of the tracts was performed using anatomical landmarks, to avoid deformations caused by cerebral atrophy. Initially, 38 HCs were used to optimize a threshold for the minimal size of regions that differ between groups. The fractional anisotropy, mean diffusivity, AAC, and the hemispheric asymmetry index (AI), were compared between 11 PSP patients and 15 HCs.

Results

The method was feasible for analysis of PSP patients and HCs. The AI showed that the observed hemispheric asymmetry of AAC was significantly larger in PSP patients compared with HCs in small regions of the IFO.

Conclusions

The method was successfully employed for analysis of diffusion parameters along the IFO in a patient group. This method can be potentially useful in studies of WM diseases, with or without cerebral atrophy.     

Assessing,exploring, and monitoring quality of offset colour prints

Variations in offset print quality relate to numerous parameters of printing press and paper. To maintain a constant high print quality press operators need to assess, explore and monitor quality of prints. Today assessment is mainly done manually. This paper presents a novel system for assessing and predicting values of print quality attributes, where the adopted, random forests (RFs)-based, modeling approach also allows quantifying the influence of different paper and press parameters on print quality. In contrast to other print quality assessment systems the proposed system utilises common, simple print marks known as double grey-bars. Novel virtual sensors assessing print quality attributes using images of double grey-bars are presented. The inferred influence of paper and printing press parameters on quality of colour prints shows clear relation with known print quality conditions. Thorough analysis and categorisation of related work is also given in the paper.