Газометанный \ газокислородный ракетный двигатель. Проектирование и разработка

Хімічні ракетні двигуни – є і будуть у майбутньому найбільш широко використовуваними рушіями для транспортування на орбіту Землі. Інформаційна потреба технологій, постійно зростаюче число супутників, які необхідно виводити на орбіту змушує виробників ракетної техніки будувати двигуни з більш широким діапазоном тяги і кращою якістю роботи. З іншого боку, для мінімізації впливу на навколишнє середовище в космічній промисловості, передбачається використання екологічнобезпечних видів палива. Одним з видів палива, що є екологічнобезпечним і гарантує якісну роботу, є метан. Це паливо знаходиться в області інтересів всесвітньої ракетної галузі. Однак, на сьогоднішній день, лише кілька двигунів, що використовують метан пройшли повну перевірку, що вказує на широку область можливих удосконалень цієї техніки.Головна мета статті полягає в тому, щоб проаналізувати можливість використання метану як палива для ракетних двигунів. Авторами з використанням методів чисельної газової динаміки (CFD) проведені обчислення експериментального ракетного двигуна. Проведений аналіз є основою для проектування експериментального зразка. Експериментальне дослідження роботи нового двигуна проведено з метою підтвердження правильності обчислень. У майбутньому планується випробовування системи охолодження двигуна, що буде завершенням даного проекту.Chemical rocket engines are still and will be in the foreseeable future the most widely used means of propulsion systems in transportation into the earth's orbit. What is more, information technologies need more and more satellites constellations to be replenished. This forces the rocket industry to build rocket engines with wider range of thrust and better performance. On the other hand, in order to minimize the influence on the environment, ecologically-safe propellants are considered to be used in space industry [1]. One of propellants, which is ecologically-safe and guarantees good overall performance is methane. This fuel is in area of interests of world's rocket industry. However, till today only a few methane rocket engines were tested, so it seems to be a wide area of possible improvements in this field. The main aim of the paper will be to analyze the possibility of using methane as a fuel for the rocket engine. The authors made the computations of a model rocket engine, fueled by methane, using CFD method. The analysis stands as the basis for the design of a model rocket engine. Experimental research to check the calculations’ validity as well as testing of its cooling system will complete the design.Химические ракетные двигатели являются и будут в обозримом будущем, наиболее широко используемыми двигательными установками для транспортирования на орбиту Земли. Информационная потребность технологий, постоянно растущее число спутников, которые необходимо выводить на орбиту, вынуждает производителей ракетной техники строить двигатели с более широким диапазоном тяги и лучшим качеством работы. С другой стороны, для минимизации влияния на окружающую среду в космической промышленности, предполагается использование экологически безопасных видов топлива. Одним из видов топлива, которое является экологически-безопасным и гарантирует качественную работу, является метан. Это топливо находится в области интересов всемирной ракетной отрасли. Однако, на сегодняшний день, лишь несколько двигателей, использующих метан, прошли полную проверку, что указывает на широкую область возможных усовершенствований этой техники. Главная цель статьи состоит в том, чтобы проанализировать возможность использования метана как топлива для ракетных двигателей. Авторами с использованием методов численной газовой динамики (CFD) проведены вычисления экспериментального ракетного двигателя. Проведенный анализ является основой для проектирования экспериментального образца. Экспериментальное исследование работы нового двигателя проведено с целью подтверждения правильности вычислений. В будущем планируется испытание системы охлаждения двигательной установки, которое будет являться завершением данного проекта

Common Atlas Format and 3D Brain Atlas Reconstructor: Infrastructure for Constructing 3D Brain Atlases

One of the challenges of modern neuroscience is integrating voluminous data of diferent modalities derived from a variety of specimens. This task requires a common spatial framework that can be provided by brain atlases. The first atlases were limited to two-dimentional presentation of structural data. Recently, attempts at creating 3D atlases have been made to offer navigation within non-standard anatomical planes and improve capability of localization of different types of data within the brain volume. The 3D atlases available so far have been created using frameworks which make it difficult for other researchers to replicate the results. To facilitate reproducible research and data sharing in the field we propose an SVG-based Common Atlas Format (CAF) to store 2D atlas delineations or other compatible data and 3D Brain Atlas Reconstructor (3dBAR), software dedicated to automated reconstruction of three-dimensional brain structures from 2D atlas data. The basic functionality is provided by (1) a set of parsers which translate various atlases from a number of formats into the CAF, and (2) a module generating 3D models from CAF datasets. The whole reconstruction process is reproducible and can easily be configured, tracked and reviewed, which facilitates fixing errors. Manual corrections can be made when automatic reconstruction is not sufficient. The software was designed to simplify interoperability with other neuroinformatics tools by using open file formats. The content can easily be exchanged at any stage of data processing. The framework allows for the addition of new public or proprietary content

Mobile test stand for rocket engines

W artykule przedstawiono projekt koncepcyjny mobilnej hamowni silników rakietowych o ciągu do 10kN. Stanowisko do badania silników wraz z systemem zasilania i niezbędnym oprzyrządowaniem zamontowane jest na samochodzie terenowym, dzięki czemu testy odbywać się mogą w bezpiecznych lokalizacjach, z dala od terenów zamieszkałych. Systemy hamowni przystosowane są do zasilania silnika kriogenicznym materiałem pędnym - w szczególności ciekłym metanem oraz ciekłym tlenem.A concept of the mobile test stand for rocket engines is proposed The test stand with its equipment (including pressure feed system) is mounted on all-terrain vehicle, which enables running the experiments in suitable locations, away from the living site. The test stand will be able to captive firing liquid rocket engines with thrust up to 10kN, that are operating especially on liquid methane and liquid oxygen

Investigation of heat transfer behind detonation wave

Wartykule przedstawiono wyniki badań nad wymianą ciepła za falą detonacyjną propagującą w jednorodnej, stacjonarnej mieszaninie H2-O2. Badania przeprowadzone zostały na poziomie eksperymentalnym jak i teoretycznym. Część eksperymentalna skupia się na szybkim pomiarze temperatury na drodze, propagującej w rurze uderzeniowej, fali detonacyjnej, na podstawie którego wyznaczyć można strumień ciepła przekazywany do ścianki. Wyniki eksperymentów porównane zostały z wynikami obliczeń teoretycznych. Obliczenia przeprowadzone zostały w oparciu o model analityczny zaproponowany przez Sichela i Davida [1], w którym jako parametry wejściowe wykorzystano wyniki symulacji CFD (Obliczeniowej Mechaniki Płynów, ang. Computational Fluid Dynamics) nielepkiego, reagującego gazu. Uzyskane wyniki posłużą do oceny możliwości chłodzenia komory spalania wykorzystującej zjawisko wirującej detonacji.Investigation of heat transfer behind detonation wave that propagates in stationary, homogeneous H2-O2 mixture is described in this article. Investigation was conducted both experimentally and theoretically. Experiments were carried in the shock tube, and focused on fast temperature measurements which were the basis for evaluation of heat flux behind detonation wave. Calculations were conducted using analytical model proposed by Sichel and David. Input parameters for the model were obtained via CFD simulations of reactive, compressible, inviscid flow. The results will be useful for evaluation of heat transfer in Rotating Detonation Combustion Chamber

Development of liquid green propellant rocket engines

W artykule zawarto zestawienie i omówienie ekologicznych materiałów pędnych będących obecnie tematem najliczniejszych publikacji w zakresie badań nad ciekłymi rakietowymi materiałami pędnymi stanowiącymi realną alternatywę dla obecnie stosowanych mieszanin typu MMH/MON, UDMH/NTO, czy hydrazyna. Należą do nich ADN, HAN, HNF oraz HTP. Dodatkowo, przedstawione zostały programy badań kosmicznych, gdzie jako źródło napędu platform satelitarnych zastosowanie znalazły opisane ekologiczne materiały pędne. Przedstawiono również wyzwania stojące przed konstruktorami pracującymi nad silnikami na ciekłe materiały pędne, a także trendy dotyczące ich przyszłych zastosowań.This article contains the survey of the non-toxic, environment friendly and low cost, green propellants being intensively investigated by the space propulsion communities. These propellants represent compounds with the highest potential to be used as an alternatives for the mixture of MMH/MON, UDMH/NTO or hydrazine in monopropellant propulsion. They include ADN, HAN, HNF and HTP. Additionally, the newest space missions with the utilization of the green propellants in their ACS (Attitude Control Systems) were described. The new challenges for the design and determination of the current trends in the field of development of the liquid rocket engines are also included

Heat Generation in Cratonic Mantle Roots—New Trace Element Constraints From Mantle Xenoliths and Implications for Cratonic Geotherms

Abstract Heat generation within the cratonic lithospheric mantle (CLM) is an important but poorly determined parameter for constructing cratonic geotherms. Direct measurement of heat producing element (HPE: K, U, and Th) concentrations in bulk‐rock samples of cratonic mantle roots—provided as xenoliths in volcanic rocks such as kimberlites—is mostly compromised by infiltration of host melt into the xenoliths, resulting in over‐estimates of heat production. Here we use in situ methods (laser ablation inductively coupled plasma mass spectrometry) on minerals from a variety of cratonic mantle peridotites to avoid host‐magma contamination enabling new, more accurate determinations of heat production for a wide spectrum of model mantle lithologies. The most melt‐depleted, least metasomatized peridotites indicate that heat generation in un‐metasomatized depleted cratonic lithospheric mantle is negligible, at ∼0.00004 µW/m3, 102 to 103 times less than models that use more enriched or metasomatized compositions. Refertilized cratonic peridotites, typical of many kimberlite hosted xenoliths, have more elevated, but still low heat generation, of 0.006 µW/m3. We propose that the heat generation of typical cratonic mantle peridotite lies between these two bounds, that is, between 0.00004 and 0.006 µW/m3. Both values produce lower estimates of lithospheric thickness, by ∼10 to up to 80 km, depending on model assumptions, than estimates using higher HPE concentrations measured on bulk‐rock xenolith material

The impact of the diurnal cycle on the microbial transcriptome in the rhizosphere of barley.

While root exudation follows diurnal rhythms, little is known about the consequences for the microbiome of the rhizosphere. In this study, we used a metatranscriptomic approach to analyze the active microbial communities, before and after sunrise, in the rhizosphere of barley. We detected increased activities of many prokaryotic microbial taxa and functions at the pre-dawn stage, compared to post-dawn. Actinomycetales, Planctomycetales, Rhizobiales, and Burkholderiales were the most abundant and therefore the most active orders in the barley rhizosphere. The latter two, as well as Xanthomonadales, Sphingomonadales, and Caulobacterales showed a significantly higher abundance in pre-dawn samples compared to post-dawn samples. These changes in taxonomy coincide with functional changes as genes involved in both carbohydrate and amino acid metabolism were more abundant in pre-dawn samples compared to post-dawn samples. This study significantly enhances our present knowledge on how rhizospheric microbiota perceives and responds to changes in the soil during dark and light periods

A T-DNA mutant screen that combines high-throughput phenotyping with the efficient identification of mutated genes by targeted genome sequencing.

Background: Nitrogen dioxide (NO2) triggers hypersensitive response (HR)-like cell death in Arabidopsis thaliana. A high-throughput mutant screen was established to identify genes involved in this type of programmed cell death.Results: Altogether 14,282 lines of SALK T-DNA insertion mutants were screened. Growing 1000 pooled mutant lines per tray and simultaneous NO2 fumigation of 4 trays in parallel facilitated high-throughput screening. Candidate mutants were selected based on visible symptoms. Sensitive mutants showed lesions already after fumigation for 1 h with 10 ppm (ppm) NO2 whereas tolerant mutants were hardly damaged even after treatment with 30 ppm NO2. Identification of T-DNA insertion sites by adapter ligation-mediated PCR turned out to be successful but rather time consuming. Therefore, next generation sequencing after T-DNA-specific target enrichment was tested as an alternative screening method. The targeted genome sequencing was highly efficient due to (1.) combination of the pooled DNA from 124 candidate mutants in only two libraries, (2.) successful target enrichment using T-DNA border-specific 70mer probes, and (3.) stringent filtering of the sequencing reads. Seventy mutated genes were identified by at least 3 sequencing reads. Ten corresponding mutants were re-screened of which 8 mutants exhibited NO2-sensitivity or -tolerance confirming that the screen yielded reliable results. Identified candidate genes had published functions in HR, pathogen resistance, and stomata regulation.Conclusions: The presented NO2 dead-or-alive screen combined with next-generation sequencing after T-DNAspecific target enrichment was highly efficient. Two researchers finished the screen within 3 months. Moreover, the target enrichment approach was cost-saving because of the limited number of DNA libraries and sequencing runs required. The experimental design can be easily adapted to other screening approaches e.g. involving high-throughput treatments with abiotic stressors or phytohormones

Prokaryotes in subsoil - evidence for a strong spatial separation of different phyla by analysing co-occurrence networks.

Microbial communities in soil provide a wide range of ecosystem services. On the small scale, nutrient rich hotspots in soil developed from the activities of animals or plants are important drivers for the composition of microbial communities and their functional patterns. However, in subsoil, the spatial heterogeneity of microbes with differing lifestyles has been rarely considered so far. In this study, the phylogenetic composition of the bacterial and archaeal microbiome based on 16S rRNA gene pyrosequencing was investigated in the soil compartments bulk soil, drilosphere, and rhizosphere in top- and in the subsoil of an agricultural field. With co-occurrence network analysis, the spatial separation of typically oligotrophic and copiotrophic microbes was assessed. Four bacterial clusters were identified and attributed to bulk topsoil, bulk subsoil, drilosphere, and rhizosphere. The bacterial phyla Proteobacteria and Bacteroidetes, representing mostly copiotrophic bacteria, were affiliated mainly to the rhizosphere and drilosphere—both in topsoil and subsoil. Acidobacteria, Actinobacteria, Gemmatimonadetes, Planctomycetes, and Verrucomicrobia, bacterial phyla which harbor many oligotrophic bacteria, were the most abundant groups in bulk subsoil. The bacterial core microbiome in this soil was estimated to cover 7.6% of the bacterial sequencing reads including both oligotrophic and copiotrophic bacteria. In contrast the archaeal core microbiome includes 56% of the overall archaeal diversity. Thus, the spatial variability of nutrient quality and quantity strongly shapes the bacterial community composition and their interaction in subsoil, whereas archaea build a stable backbone of the soil prokaryotes due to their low variability in the different soil compartments

Tracing long-distance electron transfer and cable bacteria in freshwater sediments by agar pillar gradient columns.

Cable bacteria (CB) perform electrogenic sulphur oxidation (e-SOX) by spatially separating redox-half-reactions over cm-distances. For freshwater systems, the ecology of CB is not yet well understood, partly because they proved difficult to cultivate. This study introduces a new "agar pillar" approach to selectively enrich and investigate CB-populations. Within sediment columns, a central agar pillar is embedded, providing a sediment-free gradient-system in equilibrium with the surrounding sediment. We incubated freshwater sediments from a streambed, a sulfidic lake, and a hydrocarbon polluted aquifer in such agar pillar columns. Microprofiling revealed typical patterns of e-SOx, such as the development of a suboxic zone and the establishment of electric potentials. The bacterial communities in the sediments and agar pillars were analysed over depth by PacBio near-full-length 16S rRNA gene amplicon sequencing, allowing for a precise phylogenetic placement of taxa detected. The selective niche of the agar pillar was preferentially colonized by CB related to Candidatus Electronema for surface-water sediments, including several potentially novel species, but not for putative groundwater CB affiliated with Desulfurivibrio spp. The presence of CB was seemingly linked to co-enriched fermenters, hinting at a possible role of e-SOx-populations as an electron sink for heterotrophic microbes. These findings add to our current understanding of the diversity and ecology of CB in freshwater systems, and to a discrimination of CB from surface and groundwater sediments. The agar pillar approach provides a new strategy that may facilitate the cultivation of redox gradient-dependent microorganisms, including previously unrecognized CB populations