1,435 research outputs found
On energy harvesting from ambient vibration
No full textFuture MEMS devices will harvest energy from their environment. One can envisage an autonomous condition monitoring vibration sensor being powered by that same vibration, and transmitting data over a wireless link; inaccesible or hostile environments are obvious areas of application. The base excitation of an elastically mounted magnetic seismic mass moving past a coil, considered previously by several authors, is analysed in detail. The amplitude of the seismic mass is limited in any practical device and this, together with the magnitude and frequency of the excitation define the maximum power that can be extracted from the environment. The overall damping coefficient (part of which is mechanical) is associated with the harvesting and dissipation of energy and also the transfer of energy from the vibrating base into the system
Applying the Flood Vulnerability Index as a Knowledge base for flood risk assessment
No full textFloods are one of the most common and widely distributed natural risks to life and property worldwide. An important part of modern flood risk management is to evaluate vulnerability to floods. This evaluation can be done only by using a parametric approach. Worldwide there is a need to enhance our understanding of vulnerability and to also develop methodologies and tools to assess vulnerability. One of the most important goals of assessing flood vulnerability is to create a readily understandable link between the theoretical concepts of flood vulnerability and the day-to-day decision-making process and to encapsulate this link in an easily accessible tool.Hydraulic EngineeringCivil Engineering and Geoscience
The Impact of Soil Erosion in the Upper Blue Nile on Downstream Reservoir Sedimentation
No full textPopulation growth in the Blue Nile Basin has led to fast land-use changes from forest to agricultural land, which resulted in speeding up the soil erosion processes producing highly negative impacts on the local soil fertility and agricultural productivity. The eroded sediment is transported downstream by water and sinks in the lower basin where it significantly reduces reservoir storage and irrigation canals capacity. The only effective solution to mitigate the sedimentation problem is to limit the sediment inputs from upstream by locally implementing erosion control practices. However, given the vastness and remoteness of the involved areas, this first requires the knowledge of the most critical zones. The book identifies the sources of the sediment depositing in the Lower Blue Nile Basin and quantifies the amounts involved providing essential information for the planning and implementation of any interventions aiming at reducing soil erosion. The methods used consist of extensive field work covering most of the basin, watershed, hydrodynamic and morphodynamic modelling and, for the first time, the mineralogical analysis of the sediment at the sources and sinks. The method is successful in indentifying the areas providing most of the transported sediment, where it is recommended to start with erosion control practices.Hydraulic EngineeringCivil Engineering and Geoscience
Работа в советской авиапромышленности. Из воспоминаний Г.А. Черемухина
No full textPublished by N.G. Georguiyeva This is a publication of an excerpt from the G.A. Cheremukhin's memoirs «The work in the aircraft industry» (1921-2009). He was a famous aircraft designer noted both in Russia and abroad. This fragment contains the previously little known information on the beginning of the creation of a strategic bomber TU-4 in 1945-1947. N.G. Georgieva prepared this publication on the basis of the manuscript of his memoirs. The preface and footnotes contain biographic data on people who were mentioned in the memoirs and who were working together with the author of the memoirs.Публикация отрывка из воспоминаний «Работа в советской авиапромышленности» Г.А. Черемухина (1921-2009) - известного в России и за рубежом российского авиаконструктора. Приведенный отрывок содержит малоизвестную информацию о начале создания в 1945-1947 гг. стратегического бомбардировщика Ту-4. Публикация подготовлена Н.Г. Георгиевой по рукописи воспоминаний. Введение и примечания содержат биографические сведения об упомянутых в тексте мемуаров лицах, работавших с автором воспоминаний
PUBLICATIONS OF URAL FORESTER N.G. MALGIN IN THE “MINING JOURNAL” (1860s)
No full textАвтор реконструирует и интерпретирует идеи известного уральского лесничего XIX в. Н.Г. Мальгина о проблемах и перспективах развития лесного дела на горнозаводском Урале.The author reconstructs and interprets the ideas of the famous Ural forester of the 19th century N.G. Malgin about the problems and prospects for the development of forestry in the mining plant Urals
The challenges of machine translation of academic publications
No full textClear translation remains a major challenge to better communication and understanding of the international academic literature, despite advances in Machine Translation (MT). Automatic translation systems which captured the detail and the sense of any manuscript in any language for a reader from any other linguistic background would find global applications.In this article, we discuss the current opportunities and constraints to the wider use of machine translation and computer-assisted human translation (CAT). At the present stage of technology development, these instruments offer a number of advantages to specialists working with scientific texts. These include the facility to skim and scan large amounts of information in foreign languages, and to act as digital dictionaries, thesauri and encyclopedias. Word-to-word and phrase-to-phrase translation between many languages and scripts is now well advanced. The availability of modern machine translation has therefore changed the work of specialist scientific translators, placing greater emphasis on more advanced text and sense editing skills. However, machine translation is still challenged by the nuances of language and culture from one society to another, particularlyin the freestyle literature of the arts and humanities. Scientific papers are generally much more structured, but the quality of machine translation still largely depends on the quality of the source text. This varies considerably between different scientific disciplines and from one author to another. The most advanced translation systems are making steady progress. It is timely to revisit traditional training programmes in the field of written translation to focus on the development of higher-level research competencies, such as terminology search, and so to make best use of evolving machine translation technologies. More widely, we consider that there is a challenge across the higher education systems in all countries to develop a simple, clear and consistent “international” writing style to assist fast, reliable and low-cost machine translation and hence to advance mutual understanding across the global scientific literature
Early work of N.G. (Dick) de Bruijn in analysis and some of my own
No full textThere are parallels between de Bruijn’s early work in analysis and that of the author. However, Dick’s work soon became much broader and deeper. While the present paper reviews several topics of common interest, its main content is a short version of Dick’s important article related to Riemann’s Hypothesis, entitled ‘The roots of trigonometric integrals’ [N.G. de Bruijn, The roots of trigonometric integrals, Duke Math. J. 17 (1950) 197-226]. The associated ‘de Bruijn-Newman constant’ is also discussed
Monograph review: Valeeva N.G. Chistopol county zemstvo of the Kazan province (1865–1914)
No full textThe article gives an overview of the monograph of N.G. Valeeva Chistopol County Zemstvo of the Kazan province (1865–1914). Being a study of local lore in the book, at the same time, questions related to the institute of zemstvo self-government are raised. Using the example of the zemstvo of one of the largest districts of the Kazan province, the mechanism of the functioning of local government is presented. Particular attention is paid to Zemstvo events in the field of medicine, education and agriculture. The author attaches great importance to the personality factor and, applying an anthropological approach, shows the influence of individual outstanding zemstvo people on the development of the county
Low head hydropower for local energy solutions
No full textThe role of small hydropower is becoming increasingly important on a global level. Increasing energy demand and environmental awareness has further triggered research and development into sustainable low cost technologies. In developing countries, particularly in rural areas, local power generation could considerably improve living conditions. With this in mind, the development of a next generation low head hydropower machines was subject of investigation in the EU-project HYLOW. Being part of the research lines of that project, this thesis presents a numerical modelling approach to improve the design of machines like water wheels for increased hydraulic efficiency. Nowadays, Computational Fluid Dynamics (CFD) enables numerical models to be quite accurate and incorporate physical complexities like free surfaces and rotating machines. The results of the CFD simulations carried out in this research show that a change in blade geometry can result in higher torque levels, thereby increasing performance. Numerical simulations also enabled to determine the optimal wheel-width to channel-width ratio and further improve performance by modifying the channel bed conditions upstream and downstream of the water wheel. With a power rating in the low kilowatt range, low-head hydropower machines like optimised water wheels seem to have a clear potential for small-scale energy generation, thereby contributing to achieving the Sustainable Development Goals by providing local energy solutions.Dissertation submitted in fulfillment of the requirements of the Board for Doctorates of Delft University of Technology and of the Academic Board of the UNESCO-IHE Institute for Water Education.Environmental Fluid Mechanic
Changes in the visual analyzer occurring as a result of space flight
No full text
M.A. Valyakh1,2, N.G. Baeva1,2
1 City Clinical Hospital No. 15, Moscow, Russian Federation
2 Pirogov Russian National Research Medical University, Moscow, Russian Federation
Nowadays, objectives of space medicine are to study the impact of space factors (microgravity, hypogravity, space radiation) on the human body, as well as to develop recommendations for improving the performance of crew members during space expeditions.
Microgravity occurs while being at a great distance from celestial bodies when their gravitational influence is very small. And hypogravity, in turn, is a variant of reduced gravity.
Over the past few years, NASA officers have repeatedly recorded changes in the visual organ of astronauts after long space missions, in particular, they manifested an optic nerve swelling, a reduction in the anterior-posterior axial length of the eye, a change in blood flow velocity, and hypermetropia. European scientists obtained similar data. Also, velvet-like exudates were ophthalmoscopically revealed and visual field loss was recorded. National scientists have reported a varying severity of optic nerve swelling in astronauts after long space missions.
The article presents a structured review of the results of both foreign and national scientists as a result of astronaut survey during space missions and after their completion.
Key words: microgravity, hypogravity, space flight, intraocular pressure, optic nerve swelling, hypermetropia, intracranial pressure.
For citation: Valyakh M.A., Baeva N.G. Changes in the visual analyzer occurring as a result of space flight. Russian Journal of Clinical Ophthalmology. 2019;19(1):27–30.
About the authors:
1,2Maxim A. Valyakh — ophthalmologist, assistant of the Department of Ophthalmology;
1,2Nadezhda G. Baeva — ophthalmologist; graduate student.
1City Clinical Hospital No. 15. 23, Veshnyakovskaya str., Moscow, 111539, Russian Federation.
2Pirogov Russian National Research Medical University. 1, Ostrovityanova str., Moscow, 117997, Russian Federation.
Contact information: Maxim A. Valyakh, e-mail: [email protected]. Financial Disclosure: no author has a financial or property interest in any material or method mentioned. There is no conflict of interests. Received 14.11.2018.<br
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