Droplet–surface impact at high pressures

The present work is a study of droplet–surface collisions at high pressures.A technique adapted from Lagrangian particle tracking is presented. The tracking technique is a hybrid between traditional high-speed, high-resolution photography used for drop studies and particle tracking velocimetry. It is suitable for high pressure systems with very short relaxation distances and with a non-steady background fluid.Collisions of droplets towards dry and wet walls were studied for systems of liquid decane with CO₂ or N₂ as gas phase, and a single component, two phase pure CO₂ system at saturation. At low impact velocities, higher deposition efficiencies were observed for collisions against the dry wall compared to the wet wall. The events are described in terms of micro-scale mechanisms. Additionally, deposition efficiency maps are given, and it is shown how to use these in two different modelling frameworks.     

Coefficient of Friction Measurements for Thermoplastics and Fibre Composites Under Low Sliding Velocity and High Pressure

Friction materials for typical brake applications are normally designed considering thermal stability as the major performance criterion. There are, however, brake applications with very limited sliding velocities, where the generated heat is insignificant. In such cases it is possible that friction materials which are untypical for brake applications, like thermoplastics and fibre composites, can offer superior performance in terms of braking torque, wear resistance and cost than typical brake linings. In this paper coefficient of friction measurements for various thermoplastic and fibre composite materials running against a steel surface are presented. All tests were carried out on a pin-on-disc test-rig in reciprocating operation at a fixed sliding speed and various pressure levels for both dry and grease lubricated conditions. Moreover, a generic theoretical framework is introduced in order to interpret the changes of friction observed during the running-in phase.     

Household air pollution from wood burning in two reconstructed houses from the Danish Viking Age

During 13 winter weeks, an experimental archeology project was undertaken in two Danish reconstructed Viking Age houses with indoor open fireplaces. Volunteers inhabited the houses under living conditions similar to those of the Viking Age, including cooking and heating by wood fire. Carbon monoxide (CO) and particulate matter (PM_2.5) were measured at varying distances to the fireplace. Near the fireplaces CO (mean) was 16 ppm. PM_2.5 (mean) was 3.40 mg/m³, however, measured in one house only. The CO:PM mass ratio was found to increase from 6.4 to 22 when increasing the distance to the fire. Two persons carried CO sensors. Average personal exposure was 6.9 ppm, and from this, a personal PM_2.5 exposure of 0.41 mg/m³ was estimated. The levels found here were higher than reported from modern studies conducted in dwellings using biomass for cooking and heating. While this may be due to the Viking house design, the volunteer's lack of training in attending a fire maybe also played a role. Even so, when comparing to today's issues arising from the use of open fires, it must be assumed that also during the Viking Age, the exposure to woodsmoke was a contributing factor to health problems.     

丹麦区域供热水处理标准简介

在丹麦,许多区域供热系统都曾经有过由于有垢形成或由于腐蚀而造成的管道破坏及能源损失,这是由于水处理不充分或缺乏水处理造成的。当原有的区域供热系统被更新的时候,在某些部位需要修理之前将水处理水平提高通常是非常重要的。因为只有水质符合要求我们才能使系统能使用更长时间。１９８８年,ＤａｎｓｋｅＦｊｅｒｖａｒｍｅｖｅｒｋｅｒｓＦｏｒｅｎ－ｉｎｇ（丹麦区域供热协会）为适应发展需要提供了如今丹麦区域供热系统应用的给水和循环水的建议。这些标准应用的温度范围为３５℃至１８０℃,而且必须强调的是系统中不能有铝材存…     

Comparison of isolation procedures for essential oils

Summary The influence of the time of distillation on the composition of the essential oils isolated from seed of ajowan, caraway, coriander, and cumin was investigated. The oils were isolated by distillation, as well as by simultaneous distillation-extraction. It was observed that the order of recovery of the oil constituents was determined by their solubility in the distillation water. Hence, the oxygenated compounds, although with higher boiling points, distilled before the hydrocarbons. In comparison, data are included for the oils obtained by solvent extraction from ground seed of the same species. In these cases the proportion of hydro carbons was higher than in the distilled oils. There was also evidence to suggest thatp-cymene in the oils of ajowan and cumin was partly an artefact of distillation.

---

Vergleich von Isolierungsverfahren ätherischer ÖleII. Ajowan, Künunel, Koriander und Kreuzkümmel

Zusammenfassung Der Einfluß der Destillationsäuer auf die Zusammensetzung der ätherischen Öle von Ajowan, Kümmel, Koriander und Kreuzkümmel wurde untersucht. Die Öle wurden sowohl durch Destillation als auch durch ein Destillation-Extraktionsverfahren isoliert. Es wurde gezeigt, daß die Reihenfolge der Ölbestandteile während der Destillation bestimmt wurde von ihrer Löslichkeit im Destillationswasser, weshalb die höher siedenden sauerstoffhaltigen Komponenten schneller als die Kohlenwasserstoffe übergehen.Zum Vergleich wurden Angaben aufgenommen für Öle, die mit organischen Lösungsmitteln aus gemahlenen Früchten extrahiert worden waren. In diesen Fällen war die Menge der Kohlenwasserstoffe höher als bei den destillierten Ölen. Es gibt Hinweise dafür, daßp-Cymol in Ajowan- und Kreuzkümmelöl teilweise ein Artefakt der Destillation ist.

---

---

Part I: Chem. Mikrobiol. Technol. Lebensm. (in press)     

Fabrication and characterization of PEDOT nanowires based on self-assembled peptide nanotube lithography

In this article we demonstrate the use of self-assembled peptide nanotube structures as masking material in a rapid, mild and low cost fabrication of polymerized p-toluenesulfonate doped poly(3,4-ethylenedioxythiophene) (PEDOT:TsO) nanowire device. In this new fabrication approach the PEDOT:TsO nanowire avoids all contact with any organic solvents otherwise traditionally used in clean room fabrication. This can be achieved due to the intriguing properties of the self-assembled peptide nanotubes utilized as a dry etching mask for the patterning of the PEDOT:TsO nanowire. The peptide nanotubes, despite remaining stable during the reactive ion etching procedure, can be dissolved rapidly in water afterwards. The fabricated PEDOT:TsO nanowire devices exhibit excellent electrical characteristics. Finally, the potential of PEDOT:TsO nanowires as temperature sensors has been demonstrated and the high resolution of the sensor was illustrated.     

Simple tool to evaluate the impact of daylight on building energy consumption

This paper presents a simple building simulation tool for integrated daylight and thermal analysis. The tool is capable of importing the thermal and visual properties for different glazings and shading positions from the Window Information System (WIS) program. A coupled ray-tracing and radiosity methodology is used to derive the daylight levels for different sky conditions. Both detailed daylight distribution for a particular day and time and hourly discrete values on a yearly basis may be obtained. For an integrated simulation the hourly daylight levels are fed into an existing simple thermal simulation program capable of calculating energy demand and the indoor environment. Straightforward control systems for general and task lighting systems have been implemented together with a shading control strategy that adjusts the shading according to the indoor operative temperature, the risk of glare and the profile angle of the sun. The implemented daylight calculation method allows for shades from the window recess and overhang, and for distant shades blocking the sky vault. Comparisons with the ray-tracing program Radiance show that the accuracy of this approach is adequate for predicting the energy implications of photoresponsive lighting control. The amount of input is small, which makes the tool useful for integrated daylight optimisation in the early design process.     

Electrostatic force microscopy of self-assembled peptide structures

In this report electrostatic force microscopy (EFM) is used to study different peptide self-assembled structures such as tubes and particles. It is shown that not only geometrical information can be obtained using EFM, but also information about the composition of different structures. In particular we use EFM to investigate the structures of diphenylalanine peptide tubes, particles, and CSGAITIG peptide particles placed on pre-fabricated SiO(2) surfaces with a backgate. We show that the cavity in the peptide tubes could be due to the presence of water residues. Additionally we show that self-assembled amyloid peptides form spherical solid structures containing the same self-assembled peptide in its interior. In both cases transmission electron microscopy is used to verify these structures. Further, the limitations of the EFM technique are discussed, especially when the observed structures become small compared with the radius of the AFM tip used. Finally, an agreement between the detected signal and the structure of the hollow peptide tubes is demonstrated.     

Improvements on a laser scattering technique for droplet size measurements applied to a gas-liquid separation equipment

The knowledge of droplet size distributions in a gas-liquid separation equipment is of high relevance due to the importance of removal efficiency in these systems. Different techniques could be used to measure droplet size, being one of them the diffraction of a laser beam. The laser is located behind glasses, being the formation of droplets on the glasses one of the main problems encountered when using this technique.Due to this major problem, different innovative solutions have been proposed and implemented to the gas-liquid separation column in order to obtain satisfactory results. A shutter mechanism, a purge gas and combination of these two solutions were tested. It was shown that the modified technique is suitable for liquid droplet measurements under ambient conditions.It has been also shown that the combination of these two solutions reduced considerably the amount of droplets that interacts with the glasses, allowing getting better data.