Ignition Delay Times of Kerosene (Jet-A)/Air Mixtures

Ignition of Jet-A/air mixtures was studied behind reflected shock waves. Heating of shock tube at temperature of 150 C was used to prepare a homogeneous fuel mixture. Ignition delay times were measured from OH emission at 309 nm and from absorption of He-Ne laser radiation at 3.3922 micrometers. The conditions behind shock waves were calculated by one-dimensional shock wave theory from initial conditions T1, P1, mixture composition and incident shock wave velocity. The ignition delay times were obtained at two fixed pressures 10, 20 atm for lean, stoichiometric and rich mixtures (ER=0.5, 1, 2) at an overall temperature range of 1040-1380 K.Comment: V.P. Zhukov, V.A. Sechenov, and A.Yu. Starikovskii, Ignition Delay Times of Kerosene(Jet-A)/Air Mixtures, 31st Symposium on Combustion, Heidelberg, Germany, August 6-11, 200

Raman-based geobarometry of ultrahigh-pressure metamorphic rocks: applications, problems, and perspectives

Raman-based geobarometry has recently become increasingly popular because it is an elegant way to obtain information on peak metamorphic conditions or the entire pressure-temperature-time (P-T-t) path of metamorphic rocks, especially those formed under ultrahigh-pressure (UHP) conditions. However, several problems need to be solved to get reliable estimates of metamorphic conditions. In this paper we present some examples of difficulties which can arise during the Raman spectroscopy study of solid inclusions from ultrahigh-pressure metamorphic rocks

The distribution, abundance and characteristics of plastic debris along the Coast of Grândola, Portugal

Coastal clean-up campaign on the coast of Grândola is an annual practice organized by the non-governmental Portuguese organization, Brigada do Mar. With the objective of developing the marine litter monitoring on the Portuguese coast, the Portuguese Marine Litter Association participated in the project with the aim of collecting primary data about the state of coastal marine litter pollution on the coast of Grândola. A close collaboration between the Grândola Municipality, Brigada do Mar and the Portuguese Marine Litter Association was set up, in order to gather information about marine litter in the coastal area of the region. The coast of Grândola was surveyed in five sampling areas along the coastline. The survey includes numbers, characteristics and abundance data. Plastic, making up 94,24 % of the registered marine litter, is a predominant material type in the marine litter of Grândola. The quantity of marine litter items differs between the sampling areas. The highest number of items (1000) were collected near the small village of Comporta. Among the microplastics, small broken plastic pieces are the most widespread. This study is important, not only to survey the current state of the marine litter on the coast, but also to promote awareness in the society and provide information for the institutes and local government

Has spatial segregation along ethnic lines increased in Helsinki metropolitan area?

Starting from the beginning of 1990s, Finland has experienced rapid growth rates in population fractions of non-native residents, with almost half of all immigrants eventually settling in Helsinki metropolitan area. This thesis studies immigrant settlement patterns in the capital region, with the purpose of reliably quantifying and documenting dynamics of ethnic residential segregation. Formation of 'ethnic enclaves' is a widely-debated issue which might have ambiguous impact on immigrants’ economic and social outcomes. Robust inference on segregation dynamics is a prerequisite for furthering understanding of the issue. However, qualitative inference on segregation dynamics is often hindered by the fact that different spatial unit sizes and/or immigrant population fractions generate random segregation of varying magnitudes. This thesis overcomes the problem by employing index of systematic segregation which is expressed as a fraction of maximum excess dissimilarity (net of random) that could possibly occur. Index of dissimilarity (Duncan index) is chosen as a baseline measure for calculating systematic index, ensuring comparability of my research to the existing body of knowledge on the phenomenon. While index of dissimilarity reports only marginal growth in segregation, systematic measure reports almost two-fold increase in ethnic residential segregation. Employing systematic index allows reliable comparison of segregation across various immigrant groups and localities. Thus, I find that immigrants from Balkan and African countries are more segregated than other foreign-born individuals. Comparison of systematic indices across largest Finnish cities reveals that Turku has been substantially more segregated than its counterparts starting from year 1995. Eventually, I isolate the measure of segregation along ethnic lines from sorting along other dimensions, such as income. I find no evidence that increase in residential segregation is driven by widening income gap between native and immigrant population. Finally, all the findings are presented compactly in two web applications, allowing flexible controls over the choice of locality of interest, immigrant group, statistics and map-types

High throughput biofiltration for odour control at water purification plant

[Abstract] A high throughput trickling biofilter for odour control was designed basing on the principles of biotrickling filter technology developed in Moscow Bakh Institute of Biochemistry. All the necessary blocks except a fan: temperature and humidity control unit, a biofilter bed, an irrigation system, a control block and display unit are combined within one compact biofiltration module – a standard container 6000x2400x2400 mm. The plant is thermo-insulated that enables outdoor installation. The biofilter is easily scaled up by adding extra filtration beds. A typical biofiltration module rated for 5,000-10,000 m3/h has a contact time of 3-6 s (biofilter bed total volume – 10.5 m3) and a maximum footprint of 14.5 m2. After extensive pilot plant studies the first 5000 m3/h trickling biofilter easily scalable to 20000 m3/h was installed at Moscow Water Works in spring 2007 to control odour emissions - hydrogen sulfide, mercaptanes and other malodorous volatile organic compounds in up to 60 mg/m3 concentration. The performance results of the industrial biofilter are discusse

TEACHERS` SUPPORT SERVICE AS A PART OF FLEXIBLE EDUCATION CONCEPT: EXPERIENCE OF PR CHINA

In 2020 China became the first country of the world that faced all the challenges of the COVID-19 pandemic, including the ones that dealt with education. They were the first ones to provide lock-down and distance education as the only education reality as well as the first ones to face all the positive and negative repercussions of the process mentioned. That’s why the Chinese experience (both negative and positive) is worth presenting and exploring. There is one more peculiarity of the Chinese educational system that makes it unique and lets the country in a short period make a distance education system became competitive with the traditional off-line one. It is a teachers` support system that includes not only the teachers training system (vocational training activities), but also financial support for using different online-education tools, direct assistance of a group of specialists during preparing and lessoning, psychological support etc. The study aims to present the positive educational and organisation experience already approved in China. When writing the article, methods such as observation, study of normative and scientific literature were used for a comprehensive analysis of the new pedagogical reality - the teachers` support service

Disturbance impulse effects on large umbrella space reflector dynamics

Large umbrella space antennas are essential for communication, monitoring and observation of Earth and space objects. Despite investigations devoted to space antenna dynamics, the disturbance impulse shape effect on the root mean square error of spacecraft antenna reflecting surface has not been studied. This paper overcomes this gap describing disturbance impulse impact on root mean square error of spacecraftantenna reflecting surface relative to paraboloid via nonlinear finite element method. Based on numerical results root mean square dependency on disturbance time for rectangular and sine impulses was calculated. This approach could be applied in studying antenna reflecting surface response on disturbance impulse for different types of perspective large space antennas

Calculation method for cable-beam shell structures

This paper presents a calculation method suitable for cable-beam shell structures. It is based on both nonlinear finite element and force density methods. The main idea is to define the solution sequence for stress - strain state problem of above mentioned structures by nonlinear finite element method. Every successive solution involves the previous one as an initial estimate in convergent domain. To find an initial estimate for the first solution a force density method is used. The proposed method is tested on a new large space umbrella reflector

Evaluation of thermal properties of insulation systems in pitched roofs

The article outlines the basic requirements for pitched roof insulation systems. The analysis of the properties of thermal insulation materials used in insulation systems was conducted. It is substantiated that the thermal resistance of such structures on the surface of the roof is formed taking into account the thermal conductivity of thermal insulation, thermal conductivity of wooden rafters and heat loss through the leakiness of joints and mounting devices. An assessment was made of the effect of loads of various types on the heat-insulating layer, namely: the effect of the air flow in the ventilated gap; the movement of the vapor-air mixture in the material; condensation of water vapor and penetration of drip liquid; exfiltration of air at the joints of the plates and on the surfaces of contact with the supporting structures. The expediency of using products on the basis of unstitched polyethylene foam in the construction of pitched roofs with a wooden roof system, taking into account the advantages and features of this material, as well as taking into account the possibility of creating a seamless insulating shell, is substantiated