Articles de revues : « Gravitational Pump »

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Uhl, Jean-François, et Claude Gillot. « Anatomy of the veno-muscular pumps of the lower limb ». Phlebology : The Journal of Venous Disease 30, n^o 3 (10 janvier 2014) : 180–93. http://dx.doi.org/10.1177/0268355513517686.

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Objective To study the anatomy of the veno-muscular pumps of the lower limb, particularly the calf pump, the most powerful of the lower limb, and to confirm its crucial importance in venous return. Methods In all, 400 cadaveric limbs were injected with green Neoprene latex followed by an anatomical dissection. Results The foot pump is the starter of the venous return. The calf pump can be divided into two anatomical parts: the leg pump located in the veins of the soleus muscle and the popliteal pump ending in the popliteal vein with the unique above-knee collector of the medial gastrocnemial veins. At the leg level, the lateral veins of the soleus are the bigger ones. They drain vertically into the fibular veins. The medial veins of the soleus, smaller, join the posterior tibial veins horizontally. At the popliteal level, medial gastrocnemial veins are the largest veins, which end uniquely as a large collector into the popliteal vein above the knee joint. This explains the power of the gastrocnemial pump: during walking, the high speed of the blood ejection during each muscular systole acts like a nozzle creating a powerful jet into the popliteal vein. This also explains the aspiration (Venturi) effect on the deep veins below. Finally, the thigh pump of the semimembranosus muscles pushes the blood of the deep femoral vein together with the quadriceps veins into the common femoral vein. Conclusion The veno-muscular pumps of the lower limb create a chain of events by their successive activation during walking. They play the role of a peripheral heart, which combined with venous valves serve to avoid gravitational reflux during muscular diastole. A stiffness of the ankle or/and the dispersion of the collectors inside the gastrocnemius could impair this powerful pump and so worsen venous return, causing development of severe chronic venous insufficiency.

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Wang, Zaiyuan, Jiehao Wang, Fan Li, Yuhang Li, Long Tian et Qiang Liu. « Yb-Doped All-Fiber Amplifier with Low-Intensity Noise in mHz Range Oriented to Space-Borne Gravitational Wave Detection ». Applied Sciences 13, n^o 10 (22 mai 2023) : 6338. http://dx.doi.org/10.3390/app13106338.

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We present a low-intensity noise single-frequency Yb-doped all-fiber amplifier oriented to space-borne gravitational wave detection. Relative intensity noise (RIN) below −70 dBc/Hz @ 1 mHz~1 Hz was achieved by virtue of feedback-loop-based intensity noise suppression. Based on systematic noise analysis and experimental investigation, we found that the pump noise and temperature-dependent noise of the fiber splitter and the photodetector contributed mainly to the RIN of the fiber amplifier. Therefore, we carefully designed a feedback-loop-based Yb-doped all-fiber amplifier, and finely stabilized the temperature of the pump diode, fiber splitters, and photodetectors. Consequently, the RIN can be suppressed down to −72.5 dBc/Hz around 1 mHz. This low-intensity all-fiber Yb-doped amplifier can be used for space-borne gravitational-wave detection.

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Jun Lu, Yunqing Fan, Jingna Song, Huayu Tang et Chuck Yu. « Application of Hydroturbine Pump in Water Source Heat Pump Drainage Gravitational Potential Energy Recovery System ». Indoor and Built Environment 19, n^o 5 (20 août 2010) : 546–54. http://dx.doi.org/10.1177/1420326x10378808.

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Ren, Haoling, Shiyi Wu, Tianliang Lin, Yonghua Zhang, Cheng Miao et Zhongshen Li. « Energy Saving Characteristics of a Winch System Driven by a Four-Quadrant Hydraulic Pump ». Machines 10, n^o 12 (28 novembre 2022) : 1126. http://dx.doi.org/10.3390/machines10121126.

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In this study, an integrated system of winch driving and potential energy recovery using a four-quadrant pump was proposed, aimed at the large amount of recoverable gravitational potential energy in a winch system. The proposed system changed the original open system into a closed-structure part, using a four-quadrant pump to drive the winch, and an open-structure part, using an open hydraulic pump to balance torque. The closed-structure and open-structure parts were coaxial, and connected with the engine through the transfer case, which was able to make full use of the four-quadrant pump characteristics. It was able to achieve flow regeneration when the weight was lowered, and to achieve direct use of gravitational potential energy. The AMESim model of the original and proposed systems was further established according to a working characteristics analysis of the energy consumption of the winch-driving system. The simulation results verified that the proposed system kept good controllability while recovering potential energy. An experimental prototype was built; the test results showed that, compared with the original winch system, the proposed system increased lifting speed and reduced fuel consumption significantly. Additionally, diesel consumption was reduced by 87% in the descending process.

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Davis, Michael J., Joshua P. Scallan, John H. Wolpers, Mariappan Muthuchamy, Anatoliy A. Gashev et David C. Zawieja. « Intrinsic increase in lymphangion muscle contractility in response to elevated afterload ». American Journal of Physiology-Heart and Circulatory Physiology 303, n^o 7 (1 octobre 2012) : H795—H808. http://dx.doi.org/10.1152/ajpheart.01097.2011.

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Collecting lymphatic vessels share functional and biochemical characteristics with cardiac muscle; thus, we hypothesized that the lymphatic vessel pump would exhibit behavior analogous to homeometric regulation of the cardiac pump in its adaptation to elevated afterload, i.e., an increase in contractility. Single lymphangions containing two valves were isolated from the rat mesenteric microcirculation, cannulated, and pressurized for in vitro study. Pressures at either end of the lymphangion [input pressure (Pin), preload; output pressure (Pout), afterload] were set by a servo controller. Intralymphangion pressure (PL) was measured using a servo-null micropipette while internal diameter and valve positions were monitored using video methods. The responses to step- and ramp-wise increases in Pout (at low, constant Pin) were determined. PL and diameter data recorded during single contraction cycles were used to generate pressure-volume (P-V) relationships for the subsequent analysis of lymphangion pump behavior. Ramp-wise Pout elevation led to progressive vessel constriction, a rise in end-systolic diameter, and an increase in contraction frequency. Step-wise Pout elevation produced initial vessel distention followed by time-dependent declines in end-systolic and end-diastolic diameters. Significantly, a 30% leftward shift in the end-systolic P-V relationship accompanied an 84% increase in dP/d t after a step increase in Pout, consistent with an increase in contractility. Calculations of stroke work from the P-V loop area revealed that robust pumps produced net positive work to expel fluid throughout the entire afterload range, whereas weaker pumps exhibited progressively more negative work as gradual afterload elevation led to pump failure. We conclude that lymphatic muscle adapts to output pressure elevation with an intrinsic increase in contractility and that this compensatory mechanism facilitates the maintenance of lymph pump output in the face of edemagenic and/or gravitational loads.

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Mubarokhah, Lailatul, et Wijanarka Wijanarka. « Uji bakteriologis air di PDAM GT Kabupaten Magelang dengan metode MPN Quanty-Tray ». JURNAL BIOLOGI PAPUA 11, n^o 1 (29 mai 2019) : 18–23. http://dx.doi.org/10.31957/jbp.747.

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Water is the main need for life. The bacteriological requirements for clean water are the presence or absence of Coliform bacteria and E. coli in water. The purpose of this study was to determine the quality of water from gravity springs and pump springs as a source of water in Magelang Regency PDAM GT and Magelang Regency community. This study was to finding out the bacteriological test of water in Magelang Regency PGT. This study was to know bacteriological water testing techniques using the MPN Quanti-method Tray in Magelang Regency PGT. The method used in this study is the Quanty-Tray Most Probable Number (MPN) method. The sample of this study were two gravitational springs namely Sample A and Sample B and two pumping springs namely Sample C and Sample D. The results of MPN calculations from the four springs did not meet the requirements of clean water ready to be distributed to the community because Coliform in the spring gravity water and pumps and found E. coli in the pump spring water. Key words: coliform, MPN quanty-tray, bacteriological requirement.

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Chechin, L. M. « Dark matter halo as the dispersional gravitational lens ». Modern Physics Letters A 29, n^o 37 (4 décembre 2014) : 1440002. http://dx.doi.org/10.1142/s0217732314400021.

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Based on the time-variability of the dark matter (DM) parameter of state (PoS) type of [Formula: see text], the conception of dispersional gravitational lens (DGL) was proposed. The dependency of refractive index of DM halo on its own global oscillations was found. It was shown that DM does not oscillate with optical or ultraviolet and X-ray diapasons, but it may oscillate with essentially low frequency — ϖ DM ≥10-15 Hz . Hence, it is possible to talk about the ultra weak DM oscillations, and the very cold dark matter (VCDM) particles whose masses are larger than m VCDM ≥10-42 eV . It was marked briefly that DM global oscillations will gradually pump with elastic energy the galaxy's baryonic matter. Hence, they may be the real reason of its subsequent fragmentation and the inner galaxy structure formation.

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Kontos, Antonios, et Rainer Weiss. « Photon emission spectrum of ion pumps ». Review of Scientific Instruments 94, n^o 3 (1 mars 2023) : 034503. http://dx.doi.org/10.1063/5.0138917.

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As the sensitivity of gravitational-wave detectors increases, new sources of noise appear. A potential source of noise may arise from charge accumulating on the mirrors of the experiment, the origin of which can be related to UV photons from the surroundings. In order to test one hypothesis, we measured the photon emission spectrum from a type of ion pump that is used in the experiment, an Agilent VacIon Plus 2500 l/s. We found that there is significant emission of UV photons above 5 eV, capable of knocking electrons off mirrors or surrounding surfaces and charging them. Photon emission measurements were taken as a function of gas pressure, ion-pump voltage setting, and type of pumped gas. The overall emission and shape of the measured photon spectrum are consistent with bremsstrahlung as the mechanism for the production of the photons.

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Makarieva, A. M., et V. G. Gorshkov. « Biotic pump of atmospheric moisture as driver of the hydrological cycle on land ». Hydrology and Earth System Sciences Discussions 3, n^o 4 (30 août 2006) : 2621–73. http://dx.doi.org/10.5194/hessd-3-2621-2006.

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Abstract. In this paper the basic geophysical and ecological principles are jointly analyzed that allow the landmasses of Earth to remain moistened sufficiently for terrestrial life to be possible. 1. Under gravity, land inevitably loses water to the ocean. To keep land moistened, the gravitational water runoff must be continuously compensated by the atmospheric ocean-to-land moisture transport. Using data for five terrestrial transects of the International Geosphere Biosphere Program we show that the mean distance to which the passive geophysical air fluxes can transport moisture over non-forested areas, does not exceed several hundred kilometers; precipitation decreases exponentially with distance from the ocean. 2. In contrast, precipitation over extensive natural forests does not depend on the distance from the ocean along several thousand kilometers, as illustrated for the Amazon and Yenisey river basins and Equatorial Africa. This points to the existence of an active biotic pump transporting atmospheric moisture inland from the ocean. 3. Physical principles of the biotic moisture pump are investigated based on the previously unstudied properties of atmospheric water vapor, which can be either in or out of hydrostatic equilibrium depending on the lapse rate of air temperature. A novel physical principle is formulated according to which the low-level air moves from areas with weak evaporation to areas with more intensive evaporation. Due to the high leaf area index, natural forests maintain high transpiration fluxes, which support the ascending air motion over the forest and "suck in" moist air from the ocean, which is the essence of the biotic pump of atmospheric moisture. In the result, the gravitational runoff water losses from the optimally moistened forest soil can be fully compensated by the biotically enhanced precipitation at any distance from the ocean. 4. It is discussed how a continent-scale biotic water pump mechanism could be produced by natural selection acting on individual trees. 5. Replacement of the natural forest cover by a low leaf index vegetation leads to an up to tenfold reduction in mean continental precipitation and runoff, in contrast to the previously available estimates made without accounting for the biotic moisture pump. The analyzed body of evidence testifies that the long-term stability of an intense terrestrial water cycle is unachievable without the recovery of natural, self-sustaining forests on continent-wide areas.

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Makarieva, A. M., et V. G. Gorshkov. « Biotic pump of atmospheric moisture as driver of the hydrological cycle on land ». Hydrology and Earth System Sciences 11, n^o 2 (27 mars 2007) : 1013–33. http://dx.doi.org/10.5194/hess-11-1013-2007.

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Abstract. In this paper the basic geophysical and ecological principles are jointly analyzed that allow the landmasses of Earth to remain moistened sufficiently for terrestrial life to be possible. 1. Under gravity, land inevitably loses water to the ocean. To keep land moistened, the gravitational water runoff must be continuously compensated by the atmospheric ocean-to-land moisture transport. Using data for five terrestrial transects of the International Geosphere Biosphere Program we show that the mean distance to which air fluxes can transport moisture over non-forested areas, does not exceed several hundred kilometers; precipitation decreases exponentially with distance from the ocean. 2. In contrast, precipitation over extensive natural forests does not depend on the distance from the ocean along several thousand kilometers, as illustrated for the Amazon and Yenisey river basins and Equatorial Africa. This points to the existence of an active biotic pump transporting atmospheric moisture inland from the ocean. 3. Physical principles of the biotic moisture pump are investigated based on the previously unstudied properties of atmospheric water vapor, which can be either in or out of aerostatic equilibrium depending on the lapse rate of air temperature. A novel physical principle is formulated according to which the low-level air moves from areas with weak evaporation to areas with more intensive evaporation. Due to the high leaf area index, natural forests maintain high evaporation fluxes, which support the ascending air motion over the forest and "suck in" moist air from the ocean, which is the essence of the biotic pump of atmospheric moisture. In the result, the gravitational runoff water losses from the optimally moistened forest soil can be fully compensated by the biotically enhanced precipitation at any distance from the ocean. 4. It is discussed how a continent-scale biotic water pump mechanism could be produced by natural selection acting on individual trees. 5. Replacement of the natural forest cover by a low leaf index vegetation leads to an up to tenfold reduction in the mean continental precipitation and runoff, in contrast to the previously available estimates made without accounting for the biotic moisture pump. The analyzed body of evidence testifies that the long-term stability of an intense terrestrial water cycle is unachievable without the recovery of natural, self-sustaining forests on continent-wide areas.

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Firdaus, Rohim Aminullah, Munasir Munasir, Evi Suaebah et Arie Realita. « Implementasi Pembuatan Free Energy Water Pump untuk Mengatasi Ketersediaan Kebutuhan Air pada Lahan Pertanian Masyarakat Desa Manarwi Bangil Pasuruan ». Lumbung Inovasi : Jurnal Pengabdian kepada Masyarakat 7, n^o 4 (27 décembre 2022) : 710–16. http://dx.doi.org/10.36312/linov.v7i4.975.

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Bangil adalah salah satu kecamatan yang ada di Pasuruan sekaligus sebagai ibukota Kabupaten. Secara Geografis, letak Kecamatan Bangil merupakan daerah paling utara di Kabupaten Pasuruan. Pemanfaatan lahan pertanian di bangil tidak hanya digunakan untuk menanam padi, tetapi jenis tanaman dan jenis ikan air tawar bisa menjadi alternatif sebagai pemanfaatan lahan yang ada di wilayah Bangil. Menurut Badan Statistik pada tahun 2021 hasil produksi padi mengalami penurunan sebesar 0,43%. Penurunan produksi pertanian terutama di daerah bangil kelurahan Manarwi terjadi akibat kurangnya pemerataan ketersediaan air dan mengandalkan ketersediaan air di musim hujan saja. Untuk itu agar pemerataan air tercukupi dengan baik, perlu adanya alat alternatif sebagai penyalur ketersediaan kebutuhan air. Pompa air berbasis energi terbarukan bisa menjadi salah satu alternatif untuk mengatasi hal tersebut. Dengan konsep pompa air yang ramah lingkungan, mudah dibuat dan di aplikasikan, tidak membutuhkan bahan bakar atau peralatan elektronik menjadi alternatif baru dan memberikan keuntungan dalam menekan pengeluaran dan tergolong sebagai alat yang murah serta bisa digunakan dalam jangka waktu yang lama. Hal ini mendorong tim PKM untuk memberikan pengarahan dan pembuatan pompa air berbasis free energy kepada masyarakat di wilayah Manarwi. Komponene masyarakat diajak untuk terlibat dalam pembuatan dan pemanfaatan pompa air berbasis free energi ini, meliputi pemerintahan tingakat desa, dan masayarakat di wilayah manarwi. Tahapan pelatihan dan pembuatan Pompa free energy ini meliputi pengetahuan tentang free energy water pump, menjelaskan prinsip kerja free energy water pump, pembuatan free energy water pump, dan menjelaskan serta pengaplikasian free energy water pump dalam bidang pertanian. Keberhasilan pelatihan ini dievaluasi baik pelaksanaannya maupun hasilnya. Evaluasi tersebut dilakukan dengan menggunakan angket respon peserta pelatihan terhadap pelaksanaan kegiatan pelatihan. Hasil angket respon adalah sebagai berikut : terhadap perlunya kegiatan PKM ini sebesar 85%, wawasan system kerja water pump 85%, wawasan tentang prinsip gaya gravitasi pada sistem water pump 82,5%, kegiatan diskusi 80%, pembuatan alat 90%, dan perlunya perkembangan alat 92,5%. The Implementation of Making a Free Energy Water Pump to Improve the Availability of Water Needs on Agricultural Land for the Community of Manarwi Bangil Pasuruan Village Bangil is one of the sub-districts in Pasuruan, which is also the district capital. Geographically, the location of Bangil District is the northernmost area in Pasuruan Regency. The utilization of agricultural land in Bangil is not only used for planting rice, but types of plants and freshwater fish can be an alternative for land use in the Bangil area. According to the Statistics Agency, in 2021, rice production will decrease by 0.43%. The decline in agricultural production, especially in the Bangil area of ??the Manarwi sub-district, occurred due to the lack of equal distribution of water availability and reliance only on water availability in the rainy season.For this reason, so that water distribution is fulfilled correctly, it is necessary to have an alternative tool as a distributor of the availability of water needs. Renewable energy-based water pumps can be an alternative to overcome this. With the concept of a water pump that is environmentally friendly, easy to make and apply, and does not require fuel or electronic equipment, it is a new alternative. It provides the advantage of reducing expenses, is classified as a cheap tool, and can be used for a long time. This prompted the PKM team to give directions and manufacture water pumps based on free energy for the people in the Manarwi area. Community components are invited to be involved in the manufacture and use of this free energy-based water pump, including village-level government and the community in the Manarwi area. The stages of training and making this free energy pump include knowledge, explaining the working principles, making free energy water pumps, and explaining and applying free energy water pumps in agriculture. The success of this training is evaluated both in its implementation and results. The evaluation was carried out using a questionnaire from the training participants' responses to the performance of the training activities. The results of the response questionnaire are as follows: regarding the need for this PKM activity by, 85%, insight into the working system of the water pump 85%, insight into the principle of gravitational force in the water pump system 82.5%, discussion activities 80%, tool making 90%, and the need for tool development 92.5%.

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Huang, Da Wei, Bai Yan Liu et Ru Wei Zhang. « Trajectory Optimization Method for Follow-Up Control of Concrete Pump Truck ». Applied Mechanics and Materials 415 (septembre 2013) : 3–8. http://dx.doi.org/10.4028/www.scientific.net/amm.415.3.

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The follow-up control of concrete pump truck is in order to solve the problem that whole boom follows the movement of boom end under the artificial traction. Focus on real-time detection of boom end azimuth change and inverse kinematic problems of redundant boom system, two-axis gravitational accelerometer is used to detect azimuthal variation of boom end, and the best motion trajectory of boom is determined by solving constrained nonlinear optimization function which takes minimum displacement distance of barycentre for the whole boom as the optimization goal. At last, relative azimuth and translation of boom end, rotation of boom are solved together to make translation and rotation of boom being synchronization. In this way to ensure whole boom follows the artificial traction in theory. In order to verify the discussion above, matlab is used to simulate several different working conditions for the follow-up control of boom.

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Gladyshev, V. O., E. A. Sharandin, A. V. Skrabatun et P. P. Nikolaev. « Competing processes in generation of the third optical harmonic in air under femtosecond infrared repetitively pulsed excitation ». Journal of Physics : Conference Series 2081, n^o 1 (1 novembre 2021) : 012003. http://dx.doi.org/10.1088/1742-6596/2081/1/012003.

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Abstract Parametric interaction of electromagnetic and gravitational waves with the radiation generation at the third harmonic wavelength is one of the ways to detect gravitational interaction in a material medium. To implement the effect in question, superstrong fields must be used, but in this case competing nonlinear processes arise, leading to the generation of the third harmonic as a result of laser radiation filamentation. This paper investigates the characteristics of the radiation recorded for femtosecond (250 fs) laser pulses with a wavelength of λ = 1032 nm focused in air. The threshold pump power made it possible to observe the formation of a filament with concomitant generation of narrow-band radiation at the focus of the lens at the third harmonic wavelength λ = 344 nm. The research presents spectral and spatial dependences of ultraviolet radiation (λ = 344 nm) at pumping power of infrared radiation (λ = 1032 nm) of 500 mW. Energy dependences of the third harmonic generation efficiency in the power range from 150 to 1750 mW are obtained.

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Whittaker, Peter B., Xiaolin Wang, Klaus Regenauer-Lieb, David Blair et Hui Tong Chua. « Geothermal air conditioning : typical applications using deep-warm and shallow-cool reservoirs for cooling in Perth, Western Australia ». International Journal for Simulation and Multidisciplinary Design Optimization 5 (2014) : A10. http://dx.doi.org/10.1051/smdo/2013010.

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Geothermal heat is a sustainable form of alternative energy, commonly associated with the production of electricity along tectonic plate boundaries and in volcanically active zones. Outside of these special regions however it is rare to find a geothermal gradient high enough to achieve pay back on projects for generating electricity. On the other hand regions containing sedimentary aquifers are far more common and these aquifers frequently have a sufficiently high temperature gradient to make direct use of the thermal energy attractive. Meanwhile highly permeable aquifers occurring at shallow depths are possible sources for cooling water or can be both heat sources and sinks when used in combination with heat pumps. We provide a case study for the use of thermally driven absorption chillers on the University of Western Australia campus in Perth and discuss two ongoing projects: one for the heating and cooling of the offices of the Australian Resources Research Council using a reversible heat pump and the other the climate control of the planned Australian International Gravitational Observatory.

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Qian, Kun-Xi, Teng Jing et Hao Wang. « Applications of Permanent Maglev Bearing in Heart Pumps and Turbine Machine ». ISRN Mechanical Engineering 2011 (6 avril 2011) : 1–4. http://dx.doi.org/10.5402/2011/896463.

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Earnshaw's theorem (1839) stated that no stationary object made of magnets in a fixed configuration can be held in stable equilibrium by any combination of static magnetic or gravitational forces. What will happen by a moving body like a rotating passive magnetic levitator? Nobody has given an answer until now. The author applied a self-made passive magnetic bearing to radial pump and turbine machine and found that if the rotating speed could be higher than a critical value, 3250 rpm for a pump and 1800 rpm for a turbine, the rotors would be disaffiliated from stators and keep the rotation stable. It seems that the fast rotating levitator has a so-called “Gyroeffect” which makes the passive maglev rotator stable. These results have extended Earnshaw's theorem from static to dynamic equilibrium. In static state or by a speed lower than critical value, the passive maglev rotator cannot keep rotation stable; if the rotating speed is higher than critical speed, the passive magnetic levitator will have Gyroeffect and thereby stabilize its rotation.

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Uche, Chikadibia Kalu Awa, Eza Val Hyginus Udoka, Abigaba Kisakye, Kugonza Francis Maxwell et Okafor O. Wisdom. « Design of a Solar Powered Water Supply System for Kagadi Model Primary School in Uganda ». Journal of Engineering, Technology, and Applied Science (JETAS) 5, n^o 2 (26 août 2023) : 67–78. http://dx.doi.org/10.36079/lamintang.jetas-0502.548.

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The presence of water is a prerequisite condition for the existence and sustainability of life on the planet. Adequate supply of clean water is even more significant for a primary school as it ensures hydration, sanitation, hygiene leading to a general wellbeing of the pupils. This research work successful designed a solar powered water supply system for Kagadi Model Primary School (KMPS) and its environs. The research design takes into account the population of the students, total daily water demand, water source potential in terms of quality and quantity and insolation potential of the study area which formed the bed bedrock of the suitable location of the designed system. This developed system will help to distribute water fairly to the KMPS and its environ at very a cheap and steady manner for the pump will be powered with solar energy. The solar water pump will be energized using solar energy system to pump water into the storage facility (reservoir) before distributing it by the help of gravitational force to various locations for consumption. This designed solar powered energy system when implemented will curb the problem of water scarcity, provide clean water and reduce unhygienic nature of the environment as it in line with Sustainable Development Goals (SDGs). This study recommends the implementation of this design to provide clean and steady water supply for the residents of the study area.

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Stukel, Michael R., Moira Décima et Michael R. Landry. « Quantifying biological carbon pump pathways with a data-constrained mechanistic model ensemble approach ». Biogeosciences 19, n^o 15 (5 août 2022) : 3595–624. http://dx.doi.org/10.5194/bg-19-3595-2022.

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Abstract. The ability to constrain the mechanisms that transport organic carbon into the deep ocean is complicated by the multiple physical, chemical, and ecological processes that intersect to create, transform, and transport particles in the ocean. In this paper we develop and parameterize a data-assimilative model of the multiple pathways of the biological carbon pump (NEMUROBCP). The mechanistic model is designed to represent sinking particle flux, active transport by vertically migrating zooplankton, and passive transport by subduction and vertical mixing, while also explicitly representing multiple biological and chemical properties measured directly in the field (including nutrients, phytoplankton and zooplankton taxa, carbon dioxide and oxygen, nitrogen isotopes, and 234Thorium). Using 30 different data types (including standing stock and rate measurements related to nutrients, phytoplankton, zooplankton, and non-living organic matter) from Lagrangian experiments conducted on 11 cruises from four ocean regions, we conduct an objective statistical parameterization of the model and generate 1 million different potential parameter sets that are used for ensemble model simulations. The model simulates in situ parameters that were assimilated (net primary production and gravitational particle flux) and parameters that were withheld (234Thorium and nitrogen isotopes) with reasonable accuracy. Model results show that gravitational flux of sinking particles and vertical mixing of organic matter from the euphotic zone are more important biological pump pathways than active transport by vertically migrating zooplankton. However, these processes are regionally variable, with sinking particles most important in oligotrophic areas of the Gulf of Mexico and California Current, sinking particles and vertical mixing roughly equivalent in productive coastal upwelling regions and the subtropical front in the Southern Ocean, and active transport an important contributor in the eastern tropical Pacific. We further find that mortality at depth is an important component of active transport when mesozooplankton biomass is high, but it is negligible in regions with low mesozooplankton biomass. Our results also highlight the high degree of uncertainty, particularly amongst mesozooplankton functional groups, that is derived from uncertainty in model parameters. Indeed, variability in BCP pathways between simulations for a specific location using different parameter sets (all with approximately equal misfit relative to observations) is comparable to variability in BCP pathways between regions. We discuss the implications of these results for other data-assimilation approaches and for studies that rely on non-ensemble model outputs.

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Frajuca, Carlos, et Fabio da Silva Bortoli. « Limitation of Gravitational Wave Detector Niobè Sensitivity by the Frequency Tracking Noise ». International Journal of Modern Physics : Conference Series 45 (janvier 2017) : 1760017. http://dx.doi.org/10.1142/s2010194517600175.

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The gravity wave detector at the University of Western Australia was based on a bending flap of [Formula: see text] tuned near the fundamental resonant frequency of a [Formula: see text] resonant-bar of [Formula: see text] at a temperature of [Formula: see text]. The displacement of the bending flap was monitored with a [Formula: see text] superconducting re-entrant cavity transducer. The performance of the transducer is related to the development of a low noise microwave pump oscillator to drive the transducer. This work studies the influence of the frequency tracking noise of Niobè. It had a burst sensitivity of [Formula: see text] with a long term operation from 1993 to early 1998. It had the lowest observed noise temperature. Using the characteristics of the detector, NIOBÈ should had reached a much better sensitivity that the one measure. It seems that the noise introduced in the system by the frequency tracking device was not taken into account at the time of operation, this noise gives a value of [Formula: see text], what is the value that limited the detector sensitivity to the one measured at the time of operation.

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Ekong, Moses. « Perfusion Fixation : A Vital Process for Neuroanatomical Research ». NIgerian Journal of Neuroscience 8, n^o 2 (31 mars 2017) : 38–43. http://dx.doi.org/10.47081/njn2017.8.2/001.

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Perfusion fixation is a vital technique that preserves tissues, also preparing them for further techniques in histology, histochemistry, immunohistochemistry and electron microscopy. The need for proper preservation of neural tissues for morphological and immunoreactivity studies led to the discovery of this technique which mostly makes use of the vascular system to allow for uniform tissue preservation. The technique makes use of electric pressure pump or gravitational force for perfusion based on the available equipment, and the type of fixative used is determined by the type of analysis to be done. However, this method is limited when tissues other than the target are required, or when there is a delay in tissue perfusion.

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Zheng, Y., J. C. Anderson, V. Suresh et J. B. Grotberg. « Effect of Gravity on Liquid Plug Transport Through an Airway Bifurcation Model ». Journal of Biomechanical Engineering 127, n^o 5 (20 avril 2005) : 798–806. http://dx.doi.org/10.1115/1.1992529.

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Many medical therapies require liquid plugs to be instilled into and delivered throughout the pulmonary airways. Improving these treatments requires a better understanding of how liquid distributes throughout these airways. In this study, gravitational and surface mechanisms determining the distribution of instilled liquids are examined experimentally using a bench-top model of a symmetrically bifurcating airway. A liquid plug was instilled into the parent tube and driven through the bifurcation by a syringe pump. The effect of gravity was adjusted by changing the roll angle (ϕ) and pitch angle (γ) of the bifurcation (ϕ=γ=0deg was isogravitational). ϕ determines the relative gravitational orientation of the two daughter tubes: when ϕ≠0deg, one daughter tube was lower (gravitationally favored) compared to the other. γ determines the component of gravity acting along the axial direction of the parent tube: when γ≠0deg, a nonzero component of gravity acts along the axial direction of the parent tube. A splitting ratio Rs, is defined as the ratio of the liquid volume in the upper daughter to the lower just after plug splitting. We measured the splitting ratio, Rs, as a function of: the parent-tube capillary number (Cap); the Bond number (Bo); ϕ; γ; and the presence of pre-existing plugs initially blocking either daughter tube. A critical capillary number (Cac) was found to exist below which no liquid entered the upper daughter (Rs=0), and above which Rs increased and leveled off with Cap. Cac increased while Rs decreased with increasing ϕ, γ, and Bo for blocked and unblocked cases at a given Cap>Cac. Compared to the nonblockage cases, Rs decreased (increased) at a given Cap while Cac increased (decreased) with an upper (lower) liquid blockage. More liquid entered the unblocked daughter with a blockage in one daughter tube, and this effect was larger with larger gravity effect. A simple theoretical model that predicts Rs and Cac is in qualitative agreement with the experiments over a wide range of parameters.

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Wahyudi, Bagus, Akhmad Faizin et Sudjito Soeparman. « Increasing Efficiency of Overshot Waterwheel with Overflow Keeper Double Nozzle (OKDN) by Using Hydraulic Ram System ». Applied Mechanics and Materials 330 (juin 2013) : 209–13. http://dx.doi.org/10.4028/www.scientific.net/amm.330.209.

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Waterwheel has been developed over two millennia to be efficient hydraulic machine but have weaknesses due to his inability to increase the torque although the flow of water has been increased - because the efficiency of this water wheel is only dependent on the volume of buckets and gravitational those are always constant. In this study demonstrated a new method to improve the torque of overshot waterwheel (OWW) by recapturing overflow of water from the buckets and the excess flow from the channel to be converted into kinetic energy through the nozzle and then squirt against to the curve vane in the buckets by using hydraulic ram pump system. The result of performance test proved that OKDN using hydraulics ram able to improve their efficiency more than conventional overshot wheel.

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Xu, Yanhe, Jianzhong Zhou, Chu Zhang, Yuncheng Zhang, Chaoshun Li et Zhongdong Qian. « A parameter adaptive identification method for a pumped storage hydro unit regulation system model using an improved gravitational search algorithm ». SIMULATION 93, n^o 8 (1 mars 2017) : 679–94. http://dx.doi.org/10.1177/0037549717695669.

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With increasing wind farm, solar farm, and pump storage plant integrations, intense frequency fluctuation of the pumped storage hydro unit (PSHU) under the no-load running condition, which is caused by its operation along the S-shaped curve, has been noted and researched. So, parameter identification of the PSHU regulation system (PSHURS) is crucial in precise modeling of the PSHU and can provide support for the optimized control and stability analysis of the power system. In this paper, a parameter adaptive identification method together with an improved gravitational search algorithm (IGSA) is proposed and applied to solve the identification problem for a PSHURS under the no-load condition. The IGSA, which is based on the standard gravitational search algorithm, accelerates convergence speed with a combination of the Pbest- Gbest-guided search strategy and the adaptive elastic-ball method and improves the local optimal with the added chemotaxis operator of the bacterial foraging algorithm. Furthermore, for the parameter adaptive identification method, the parameter performance evaluator is employed to devise the moving step of the agent of the chemotaxis operator. The illustrative experiment for parameter identification of the PSHURS is used to verify the feasibility and effectiveness of the proposed method. Comparison with other methods clearly shows that the adaptive parameter identification method along with the IGSA perform best for all identification indicators.

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Zhang, Yong Yong. « A Design Scheme of Device for Producing Fresh Water ». Advanced Materials Research 912-914 (avril 2014) : 559–62. http://dx.doi.org/10.4028/www.scientific.net/amr.912-914.559.

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This paper designed a new device for producing fresh water. In order to solve the problem of freshwater shortage in the offshore drilling platform or barren island, Firstly the device will change wave energy into gravitational potential energy of the floater. Then the gravitational potential energy of the floater is converted into mechanical energy by the intermediate transmission device. and mechanical energy is converted into pressure energy by the vacuum pump. The pressure of the system is reduced. The saturation temperature of water is further fall. Then the evaporation of seawater required heat is reduced. so the device has the effect of saving energy. Firstly, this paper established the mathematical model in the steady state. Through the analysis of the mathematical model, water production can meet the fresh water requirements of offshore drilling platforms, the device has the economic efficiency and good energy saving effect.. Research contents Firstly, through consulting data and sampling methods, we determine the amount of fresh water of offshore drilling platform on one day, and the minimum water production capacity should be determined; and determine the structural frame work platform sea area near the stable system and weather related natural factors (example: wind speed, wave height, wave cycle).The related natural factors in each season the working platform nearby the offshore drilling platform should be determined.(example: wind speed, wave height, wave cycle). Secondly, according to the analysis of survey results and data, we calculate the dilution tank capacity and the minimum pressure to bear; designing shape of floater , the determination of its size, the reasonable selection of materials, rational design of the wave shape, determine the size, screening materials; reasonable arrangements for the design of negative pressure fresh water conversion device installation. The reasonable installation of the device on the drilling platform Thirdly, we consider the low limit, tank capacity and the size of floater, and errors should be taken into account, then we can determine the working volume of vacuum pump, selecting materials, reasonable pipeline design; determining the size of solar panels and the calculation of the generation. Fourthly, we calculate the minimum driving force, the average working distance of float and power of the pump by the data Fifthly, we considering the various data, then testing weather design of the device is very reasonable through the reasonable calculation; And according to the minimum driving force and float force, we calculate parameters of intermediate transmission mechanism, the design efficient transmission device; by considering the proper placement of solar energy device. Fig. 1 is the research process. Fig. 1 the research process

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Nazir, Muhammad Shahzad, Sami ud Din, Wahab Ali Shah, Majid Ali, Ali Yousaf Kharal, Ahmad N. Abdalla et Padmanaban Sanjeevikumar. « Optimal Economic Modelling of Hybrid Combined Cooling, Heating, and Energy Storage System Based on Gravitational Search Algorithm-Random Forest Regression ». Complexity 2021 (13 mai 2021) : 1–13. http://dx.doi.org/10.1155/2021/5539284.

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The hybridization of two or more energy sources into a single power station is one of the widely discussed solutions to address the demand and supply havoc generated by renewable production (wind-solar/photovoltaic (PV), heating power, and cooling power) and its energy storage issues. Hybrid energy sources work based on the complementary existence of renewable sources. The combined cooling, heating, and power (CCHP) is one of the significant systems and shows a profit from its low environmental impact, high energy efficiency, low economic investment, and sustainability in the industry. This paper presents an economic model of a microgrid (MG) system containing the CCHP system and energy storage considering the energy coupling and conversion characteristics, the effective characteristics of each microsource, and energy storage unit is proposed. The random forest regression (RFR) model was optimized by the gravitational search algorithm (GSA). The test results show that the GSA-RFR model improves prediction accuracy and reduces the generalization error. The detail of the MG network and the energy storage architecture connected to the other renewable energy sources is discussed. The mathematical formulation of energy coupling and energy flow of the MG network including wind turbines, photovoltaic (PV), CCHP system, fuel cell, and energy storage devices (batteries, cold storage, hot water tanks, and so on) are presented. The testing system has been analysed under load peak cutting and valley filling of energy utilization index, energy utilization rate, the heat pump, the natural gas consumption of the microgas turbine, and the energy storage unit. The energy efficiency costs were observed as 88.2% and 86.9% with heat pump and energy storage operation comparing with GSA-RFR-based operation costs as 93.2% and 93% in summer and winter season, respectively. The simulation results extended the rationality and economy of the proposed model.

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Geng, Wei Dong, Yu Gong, Li Zhang, Chun Lei Pan et Jian De Wu. « Pipeline Dehydration Station Centralized Control System ». Applied Mechanics and Materials 224 (novembre 2012) : 539–42. http://dx.doi.org/10.4028/www.scientific.net/amm.224.539.

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The iron ore concentrate transport is one of an important factor in restricting the mining economic development; pipeline is a good solution with the hydraulic. The Dongchuan pipes are the use of the gravitational potential energy to achieve transporting concentrates by the way of self-flowing drop. The project is highly energy saving demonstration. However, it has a high demand of the control system of the end of the pipe dehydration station running due to the complex topography. Centralized control system given in this paper, having the characteristic of high reliability, operating performance, real-time strong, versatile and high economic benefits. The system realize the intelligent monitoring of the whole plant, all equipment control, the detection signal into the control room, remote control of the bottom pump system on the mountain, all equipment automatically switches to control. The system has a certain generalization.

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Andrade, Luiz A., César A. Costa, Odylio D. Aguiar, Carlos Frajuca, Marbey M. Mosso, Abelardo Podcameni, Henrique J. P. P. da Silva et Nadja S. Magalhães. « Ultra-low phase noise 10 GHz oscillator to pump the parametric transducers of the Mario Schenberg gravitational wave detector ». Classical and Quantum Gravity 21, n^o 5 (13 février 2004) : S1215—S1219. http://dx.doi.org/10.1088/0264-9381/21/5/122.

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Wang, Zi-Fei, Liang Sun, Qiu-Yang Li et Hao Cheng. « Two typical merging events of oceanic mesoscale anticyclonic eddies ». Ocean Science 15, n^o 6 (25 novembre 2019) : 1545–59. http://dx.doi.org/10.5194/os-15-1545-2019.

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Abstract. The long-term theoretical “energy paradox” of whether the final state of two merging anticyclones contains more energy than the initial state is studied by considering two typical merging events of ocean mesoscale eddies. The results demonstrate that the total mass (volume), total circulation (area integration of vorticity), and total angular momentum (AM) are conserved if the orbital AM relative to the center of mass is taken into account as the eddies rotate around the center of mass before merging. For subsurface merging, the mass trapped by the Taylor–Proudman effect above the subsurface eddies should also be included. Both conservation laws of circulation and orbital AM have been overlooked in previous theoretical studies. As a result of fusion during merging, the total eddy kinetic energy decreases slightly. In contrast, the total eddy potential energy (EPE) increases after merging. The increase in EPE is mostly supported by the loss of gravitational potential energy (PE) via eddy sinking below the original level prior to merging. This implies that the merging of eddies requires background gravitational PE to be converted to EPE. In contrast, the vorticity and enstrophy consequently decrease after merging. Thus, the eddy merging effect behaves as a “large-scale energy pump” in an inverse energy cascade. It is noted that eddy conservation and conversion laws depend on the laws of physical dynamics, even if additional degrees of freedom can be provided in a mathematical model.

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Naqvi, Azmi, Dinesh C. Sharma et Pradip Nahar. « Low Cost Microfluidic Device for Assaying Blood Glucose ». Biosciences, Biotechnology Research Asia 16, n^o 2 (28 juin 2019) : 279–87. http://dx.doi.org/10.13005/bbra/2744.

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Herein, gravitational force based low cost colorimetric microfluidic device is developed for diagnostic purpose. Microfluidic system is developed by using discarded pen refills. Refill is filled with three layers of polymer. Bottom of the refill is filled with the polymer polyvinyl chloride (PVC). Second layer from the bottom i.e the layer above PVC layer is filled with silica gel immobilized with horse radish peroxidase (HRP), glucose oxidase (GOD) and o- dianisidine (dye). Whereas, third and the top most layer is filled with untreated silica gel. One drop of blood is poured at the inlet of microfluidic device. Without applying any external power, blood moves through the silica packed region by gravitational pull and capillary action of silica gel. Serum separation started within 30 seconds and subsequently within 2 min., serum successfully separates from blood by pure silica gel. The separated serum then comes in contact with the silica gel immobilized with enzymes and dye. The colour of the silica beads immobilized with enzymes and dye changes from white to orange when comes in contact with glucose in serum. Determination of the glucose in the blood is carried out on a desktop scanner. The developed microfluidic device do not require (i) pump or device to propel the fluid (ii) any type of special mesh or sieve to separate the serum from the blood. Microfluidic device developed is cheap and suitable for low cost setting areas.

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Huang, Jiamin, Qilai Zhao, Junjie Zheng, Chengzi Huang, Quan Gu, Wanpeng Jiang, Kaijun Zhou et al. « A 102 W High-Power Linearly-Polarized All-Fiber Single-Frequency Laser at 1560 nm ». Photonics 9, n^o 6 (4 juin 2022) : 396. http://dx.doi.org/10.3390/photonics9060396.

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A 1560 nm high-power linearly-polarized all-fiber single-frequency narrow-linewidth laser with near diffraction-limited beam quality is demonstrated. The Yb–Er energy transfer efficiency and the ability of the signal laser to capture pump light have been improved by specifically choosing the pumping wavelength and the input signal power in the final power amplifier stage of this laser system. Under the off-peak absorption pumping wavelength of 940 nm, along with the maximum input signal power of 6 W, a maximum output power of 102 W with a slope efficiency of 40.5% is acquired. At the highest output power status, a polarization extinction ratio (PER) of 15.5 dB, a linewidth of 3.05 kHz, and a beam quality of Mx2 = 1.14, My2 = 1.06 are obtained, respectively. This advanced single-frequency fiber laser has great potential for the long-range coherent Doppler lidar and the next generation of gravitational wave detection.

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Tang, Chuan, Chenghua Zhang, Dan He, Feng Zhang, Yu Wei, Zhongqing Yang et Yunfei Yan. « Research on Gravity Energy Saving Reconstruction Technology of Circulating Cooling Water in Mechanical Ventilation Cooling Tower of a Steel Plant ». Energies 16, n^o 17 (29 août 2023) : 6274. http://dx.doi.org/10.3390/en16176274.

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There is a height drop in the rain area of the circulating cooling water in mechanical ventilation circulating cooling towers, resulting in the ineffective use of gravitational potential energy. High-level water collection is an effective way to reduce the energy consumption of the cooling tower. Based on this, aiming to solve the gravity energy waste problem of circulating water in the cooling tower of a steel plant, this paper innovatively puts forward the high-level water tank to utilize the energy-saving transformation technology of turbine power generation and pump power saving. Additionally, this paper explores the energy-saving effects of the two methods under different height drops. The results show that the maximum utilizable rain area height of the cooling tower is 5 m, while the annual electric energy output of turbine technology can reach 4.704 million kW·h. The high water collection technology can reduce pump power consumption and save up to 7.35 million kW·h per year of electric energy, maintaining a more significant energy-saving ability compared with the turbine power generation technology. In terms of performance, the design of a high-level water tank is to help eliminate rain areas and improve the heat exchange efficiency of water and gas, so that the water temperature of the outgoing tower is 0.13 °C lower than that of the conventional cooling tower. Meanwhile, the ventilation resistance in the rain area is weakened, the resistance coefficient can be reduced by about 40–50%, and the noise can be reduced by about 10 dB (A) under the action of the water collection device. According to the economic evaluation, the total cost of turbine power generation technology is 0.563 million dollars and the total cost of high-level water collection technology is 0.446 million dollars. The cost can be realized within two years, but the high-level water collection technology avoids additional pump maintenance costs and has better economy. This study provides a theoretical basis for the transformation and optimization design of mechanical ventilation cooling towers, and has important reference value.

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Hicks, J. W., et H. S. Badeer. « Siphon mechanism in collapsible tubes : application to circulation of the giraffe head ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 256, n^o 2 (1 février 1989) : R567—R571. http://dx.doi.org/10.1152/ajpregu.1989.256.2.r567.

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Controversy exists over the principles involved in determining blood flow to the head of a giraffe, specifically over the role of gravity pressure (pgh) in the collapsible jugular vein in facilitating uphill flow in arteries. This study investigated the pressures within vertically oriented models containing both rigid and collapsible tubes. An inverted U tube was constructed (height = 103 cm) of thick rubber tubing in the ascending limb and collapsible dialysis tubing in the descending limb. Water flow was induced by a variable speed pump maintained at the reservoir level such that the descending limb was partially collapsed. Pressure measurements were made at various levels within the U tube by two methods: 1) with the transducer at same level as the tip of the water-filled catheter and 2) with the transducer at the reservoir level. During flow, the pressure at any point was nearly atmospheric along the length of the descending limb. Such methods of obtaining pressure indicated that the pressure gradient within the partially collapsed descending limb was the sum of viscous flow pressure (P1-P2 of Poiseuille) and gravitational pressure (pgh). To study the facilitatory effect of a siphon, the descending limb was compared with a horizontally placed limb (length = 100 cm), and the flow was kept constant. Calculations of hydraulic "work" (pressure x flow) indicated that with a partially collapsed descending limb, work of the pump was reduced by 15% compared with uphill flow to the elevated horizontal position. It is concluded that the siphon mechanism operates in a partially collapsed descending limb of a siphon loop.

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Scallan, Joshua P., John H. Wolpers, Mariappan Muthuchamy, David C. Zawieja, Anatoliy A. Gashev et Michael J. Davis. « Independent and interactive effects of preload and afterload on the pump function of the isolated lymphangion ». American Journal of Physiology-Heart and Circulatory Physiology 303, n^o 7 (1 octobre 2012) : H809—H824. http://dx.doi.org/10.1152/ajpheart.01098.2011.

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We tested the responses of single, isolated lymphangions to selective changes in preload and the effects of changing preload on the response to an imposed afterload. The methods used were similar to those described in our companion paper. Step-wise increases in input pressure (Pin; preload) over a pressure range between 0.5 and 3 cmH2O, at constant output pressure (Pout), led to increases in end-diastolic diameter, decreases in end-systolic diameter, and increases in stroke volume. From a baseline of 1 cmH2O, Pin elevation by 2–7 cmH2O consistently produced an immediate fall in stroke volume that subsequently recovered over a time course of 2–3 min. Surprisingly, this adaptation was associated with an increase in the slope of the end-systolic pressure-volume relationship, indicative of an increase in contractility. Lymphangions subjected to Pout levels exceeding their initial ejection limit would often accommodate by increasing diastolic filling to strengthen contraction sufficiently to match Pout. The lymphangion adaptation to various pressure combinations (Pin ramps with low or high levels of Pout, Pout ramps at low or intermediate levels of Pin, and combined Pin + Pout ramps) were analyzed using pressure-volume data to calculate stroke work. Under relatively low imposed loads, stroke work was maximal at low preloads (Pin ∼2 cmH2O), whereas at more elevated afterloads, the optimal preload for maximal work displayed a broad plateau over a Pin range of 5–11 cmH2O. These results provide new insights into the normal operation of the lymphatic pump, its comparison with the cardiac pump, and its potential capacity to adapt to increased loads during edemagenic and/or gravitational stress.

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Lee, Jun, Kiyoung Kim et Hoon Sohn. « The Unknown Abnormal Condition Monitoring Method for Pumped-Storage Hydroelectricity ». Sensors 23, n^o 14 (12 juillet 2023) : 6336. http://dx.doi.org/10.3390/s23146336.

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Pumped-storage hydroelectricity (PSH) is a facility that stores energy in the form of the gravitational potential energy of water by pumping water from a lower to a higher elevation reservoir in a hydroelectric power plant. The operation of PSH can be divided into two states: the turbine state, during which electric energy is generated, and the pump state, during which this generated electric energy is stored as potential energy. Additionally, the condition monitoring of PSH is generally challenging because the hydropower turbine, which is one of the primary components of PSH, is immersed in water and continuously rotates. This study presents a method that automatically detects new abnormal conditions in target structures without the intervention of experts. The proposed method automatically updates and optimizes existing abnormal condition classification models to accommodate new abnormal conditions. The performance of the proposed method was evaluated with sensor data obtained from on-site PSH. The test results show that the proposed method detects new abnormal PSH conditions with an 85.89% accuracy using fewer than three datapoints and classifies each condition with a 99.73% accuracy on average.

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Lv, Cong, Yanhe Xu, Xin Wu et Qing Zhang. « Characteristic Analysis and Optimal Regulation of Primary Frequency Regulation Condition in Low Water Head Area Based on Hydraulic-Mechanical-Electrical Coupling Model of Pumped Storage Unit ». Complexity 2020 (11 janvier 2020) : 1–17. http://dx.doi.org/10.1155/2020/6161784.

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Pumped storage power station is an important regulating tool for peak load regulation and frequency regulation of the power grid, especially its primary frequency regulation function, which is of profound significance for the safety and stability of the power grid. As the core equipment of the pumped storage power station, the reversible design of the pump turbine makes it easy to have hydraulic fluctuation and mechanical instability when the unit runs to the “S” characteristic area, which will cause the frequency oscillation of the generator under the condition of primary frequency regulation. Therefore, some innovative work is studied in this paper: (1) an accurate hydraulic-mechanical-electrical coupling system mathematical model of pumped storage unit regulation system (PSURS) is established based on full characteristic curve of the pump turbine and seventh-order synchronous generator and excitation system; (2) the dynamic response characteristics of primary frequency regulation of pumped storage unit (PSU) under different water heads and different frequency disturbances are analyzed by numerical simulation; (3) in view of the unstable condition of the unit under the large frequency disturbance when it operates in the low head and small load area, the objective optimization function considering the ITAE index of hydraulic, mechanical, and electrical factors is proposed; and (4) fractional-order PID controller and the bacterial-foraging chemotaxis gravitational search algorithm (BCGSA) combined optimization strategy is used for PSURS optimization regulation and parameter optimization. The results show that the joint optimization strategy proposed in this paper has smaller objective function value, and makes the PSURS pass through the unbalanced area quickly, with better primary frequency regulation speed and smaller regulation depth.

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Nygaard, Gerhard Haukenes, Erlend H. Vefring, Kjell Kåre Fjelde, Geir Naevdal, Rolf Johan Lorentzen et Saba Mylvaganam. « Bottomhole Pressure Control During Drilling Operations in Gas-Dominant Wells ». SPE Journal 12, n^o 01 (1 mars 2007) : 49–61. http://dx.doi.org/10.2118/91578-pa.

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Summary To obtain an underbalanced pressure condition, nitrogen gas can be injected into the drillstring. Simultaneous injection of liquids and gases leads to a highly dynamic flow system. During pipe connections, pressure transients can cause the bottomhole pressure to rise above the pore pressure of the reservoir or fall below the reservoir collapse pressure. Migration of gas during pipe connection and inflow from the reservoir will also cause bottomhole pressure changes. This paper presents a methodology for controlling the bottomhole pressure during drilling operations in gas-dominant wells. The methodology incorporates a dynamic model of the well fluid flow and the well-reservoir interaction. Available control actions during the drilling process are the gas injection rate prior to the pipe connection and choke valve settings during the pipe connection. Measurement of the pump rates, pump pressures, choke pressure and the bottomhole pressure are also available to support the control actions. However, during pipe connections and in the event of transient signal failures, the bottomhole pressure measurements will be suppressed. The control methodology used is based on a nonlinear model predictive control system, which predicts the near-future behavior of the well, and uses these predictions to obtain the optimal choke settings. The model parameters are calibrated using measurements from the well to ensure that the model is suitable for the predictions. A field-based case with gas injection has been examined using this control methodology. The results indicate that model based control can be utilized in developing an automated and integrated pump rate and choke-control system for underbalanced drilling operations. Introduction Injection of nitrogen gas into the drillstring while drilling is often used to obtain underbalanced pressure conditions in the reservoir section of the well. When drilling into a low-pressure reservoir, where the reservoir pore pressure is substantially lower than 1 SG, a large amount of nitrogen gas is needed to achieve underbalanced conditions. This causes the gas properties of the fluid mixture to be dominant in the well. During pipe connection, where the fluid velocity is reduced, gas and liquid segregate because of gravitational forces. In addition, loss of friction pressure causes the pressure difference between the reservoir pressure and the bottomhole well pressure to increase. This results in a larger influx of reservoir fluids into the well. To achieve more stable pressure conditions in the well, the choke setting and the circulation pump rates can be adjusted (Perez-Tellez et al. 2004; Nygaard et al. 2004). This paper evaluates a method for controlling the bottomhole pressure during the whole drilling operation, including operations related to pipe connections.

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Tamburini, Christian, Marc Garel, Aude Barani, Dominique Boeuf, Patricia Bonin, Nagib Bhairy, Sophie Guasco et al. « Increasing Hydrostatic Pressure Impacts the Prokaryotic Diversity during Emiliania huxleyi Aggregates Degradation ». Water 13, n^o 19 (23 septembre 2021) : 2616. http://dx.doi.org/10.3390/w13192616.

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In the dark ocean, the balance between the heterotrophic carbon demand and the supply of sinking carbon through the biological carbon pump remains poorly constrained. In situ tracking of the dynamics of microbial degradation processes occurring on the gravitational sinking particles is still challenging. Our particle sinking simulator system (PASS) intends to mimic as closely as possible the in situ variations in pressure and temperature experienced by gravitational sinking particles. Here, we used the PASS to simultaneously track geochemical and microbial changes that occurred during the sinking through the mesopelagic zone of laboratory-grown Emiliania huxleyi aggregates amended by a natural microbial community sampled at 105 m depth in the North Atlantic Ocean. The impact of pressure on the prokaryotic degradation of POC and dissolution of E. huxleyi-derived calcite was not marked compared to atmospheric pressure. In contrast, using global O2 consumption monitored in real-time inside the high-pressure bottles using planar optodes via a sapphire window, a reduction of respiration rate was recorded in surface-originated community assemblages under increasing pressure conditions. Moreover, using a 16S rRNA metabarcoding survey, we demonstrated a drastic difference in transcriptionally active prokaryotes associated with particles, incubated either at atmospheric pressure or under linearly increasing hydrostatic pressure conditions. The increase in hydrostatic pressure reduced both the phylogenetic diversity and the species richness. The incubation at atmospheric pressure, however, promoted an opportunistic community of “fast” degraders from the surface (Saccharospirillaceae, Hyphomonadaceae, and Pseudoalteromonadaceae), known to be associated with surface phytoplankton blooms. In contrast, the incubation under increasing pressure condition incubations revealed an increase in the particle colonizer families Flavobacteriaceae and Rhodobacteraceae, and also Colwelliaceae, which are known to be adapted to high hydrostatic pressure. Altogether, our results underline the need to perform biodegradation experiments of particles in conditions that mimic pressure and temperature encountered during their sinking along the water column to be ecologically relevant.

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Lee, Donghwa, Ilhwan Kim et Kwangjo Lee. « Investigation of 1064-nm Pumped Type II SPDC in Potassium Niobate for Generation of High Spectral Purity Photon Pairs ». Crystals 11, n^o 6 (26 mai 2021) : 599. http://dx.doi.org/10.3390/cryst11060599.

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The generation and detection of nonclassical light of about 2 μm has good potential in an emerging field of high-sensitivity metrology, especially gravitational wave detection, as well as free-space quantum communication. A pair of photons is generated through a spontaneous parametric down-conversion (SPDC) process in a nonlinear optic crystal, which can be properly entangled in a spatial region where two beams with each polarization overlap or in a Sagnac-loop interferometer configuration. We investigated theoretically and numerically Type II SPDC in a potassium niobate (KNbO3, KN) crystal, which is useful as a material platform for generating photon pairs of high spectral purity in the 2-μm range. The technique is based on the frequency degenerate SPDC under Type II extended phase matching (EPM). We described the EPM characteristics of KN and showed that it is practically feasible for a 1064-nm pumped SPDC under moderate temperature conditions. The effective nonlinear optic coefficient of KN is at least four-times larger than those of other crystals using the Type II EPM approach, which implies a significant improvement in SPDC efficiency. The joint spectral analysis showed that a pair of photons can be generated with a high purity of 0.995 through proper pump filtering.

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Tokar, Danut, Adriana Tokar et Marius Adam. « Experimental Study for the Analysis of the Potential Energy Conversion of Wastewater Discharged from Installations and Equipment’s of the Civil and Industrial Buildings ». IOP Conference Series : Materials Science and Engineering 1203, n^o 2 (1 novembre 2021) : 022076. http://dx.doi.org/10.1088/1757-899x/1203/2/022076.

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Abstract Even though the science and technology in the field of energy production for buildings has reached an advanced stage of development, there is still a considerable part of the population who do not have access to electricity. Currently, renewable energy (Solar, Wind, Geothermal, Hydro, Wave energy, Biogas), are considered sources that will meet future energy requirements, but have geographical limitations, are not available throughout the territory and are difficult to integrate into energy systems due to of the unpredictable character, their functioning being determined by the weather conditions. Also, the power and efficiency of renewable energy systems are still limited. Given that gravity (the fundamental forces of nature) is available everywhere, regardless of the climatic conditions, it represents an inexhaustible source of energy. In the context of apocalyptic scenarios or cyberattacks on energy systems, gravitational electrical systems can offer solutions for restoring electricity supply from simple to most complex solutions. The article explores the conversion of potential energy from wastewater of the technological processes, into electricity. The study was performed on an experimental stand designed to be connected to the drainage system of a water-to-water heat pump. The efficiency of potential energy conversion for applicability to wastewater discharging systems of equipping civil and industrial buildings was analysed.

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Sultanov, F. R., Ch Daulbayev, B. Bakbolat et Z. A. Mansurov. « Separation Efficiency of Water/Oil Mixtures by Hydrophilic and Oleophobic Membranes Based on Stainless Steel Meshes with Openings of Various Sizes ». Eurasian Chemico-Technological Journal 20, n^o 3 (28 septembre 2018) : 195. http://dx.doi.org/10.18321/ectj721.

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This article is focused on development of hydrophilic and oleophobic composition which serves as a coating for substrate presented by stainless steel meshes with different sizes of their openings. Membranes obtained by dip-coating method are hydrophilic and oleophobic and this may be applied for efficient separation of organic liquids and water by simple and inexpensive gravitational separation. Investigations presented in the article show that the size of openings of meshes influence on the formation of hydrophilicity and oleophobicity of membrane, as well as the nature of used polymers, which serve as a coating, since membranes based on 400 mesh coated with Poly(diallyldimethylammonium chloride) (PDDA)/ pentadecafluorooctanoic acid (PFOA)/SiO2 demonstrate different wettability in regard to organic liquids of different densities. In particular, membrane based on mesh 400 coated with PDDA/PFOA/SiO2 exhibits strong oleophobicity to less dense non-polar organic solvents – kerosene, which does not penetrate the membrane, while more dense liquids, such as vacuum pump oil, are able to penetrate it, but the rate of penetration is rather slow, 10 ml per 21 min. Obtaining of membranes with uniform coating by hydrophilic-oleophobic compositions without clogging of their openings and creation of openings of required sizes for a particular case is also a subject of study of this article.

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Sari, Dewi Purnama, Novi Kurniasih et Alex Fernandes. « Pemanfaatan Listrik Tenaga Surya Sebagai Pasokan Listrik Untuk Menghidupkan Mesin Pompa Air Masyarakat Dusun Cilatak, Desa Sukadana, Kecamatan Ciomas, Kabupaten Serang, Banten ». TERANG 3, n^o 1 (3 octobre 2020) : 68–79. http://dx.doi.org/10.33322/terang.v3i1.1019.

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The Community Service program activity of the Electricity and Renewable Energy Faculty lecturer team at the PLN Technology Institute for the 2019/2020 fiscal year was carried out in Sukadana village, Ciomas district, Serang region, Banten precisely at RT 011 RW 003 Cilatak hamlet. The selection of Sukadana village as a place to implement Community Service is because this village is still experiencing problems in the construction and development facilities and infrastructure. The problems that are currently being experienced by villagers regarding the clean water distribution for ablution of villagers in the mosque. During this time for ablution in mosque, villagers only rely on water from mountain springs whose distribution relies on gravitational pressure through a plastic hose and accommodated in a large tub located beside the mosque. In addition to being used for ablution, water is also used by villagers to bathing, washing, etc., so that when used for ablution sometimes it is no longer clean because it has been mixed with soapy water used for bathing and washing. Based on those problems, our team provided solution to partner in the form of infrastructure development and clean water supply by reconfiguring the clean water distribution installation for ablution in the mosque by installing solar water pump. The method used in the implementation of this Community Service activity is to approach the villagers during the survey through interviews by providing solution to the problem and conducting questionnaires and socialization in the form of a brief education. The results of the activities have been done by installing 2 units of DC water pump @180 Watt, 4 units of polycrystalline solar modules @100 Wp, 2 units of battery @100 Ah 12 V and 2 units of solar charge controller. With the implementation of Community Service activities in Sukadana village, aside from being able to help overcome the problems faced by partner, besides that it can provide progress and development of infrastructure for partner village and the existence of a partnership that makes that village as IT PLN assisted village.

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Hamoudi, Maha R. A., Akram H. Abdulwahhab, Amanj Walid Khalid, Deelan Authman et Rebin Ali Mohammed Ameen. « Transportation of Cuttings in Inclined Wells ». UKH Journal of Science and Engineering 2, n^o 2 (13 décembre 2018) : 3–13. http://dx.doi.org/10.25079/ukhjse.v2n2y2018.pp3-13.

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One of the most important functions performed by drilling fluid is the removal of cutting from the bottom of the hole to the surface. This function must be performed efficiently if not, the cuttings produced during drilling process will accumulate in the annulus. This problem in directional drilling is featured by gravitational forces. Problems resulting from inefficient cutting transport include pipe stuck, wear of bit, reduction in penetration rate, high torque and drag with many other problems encountered. In high angle deviated wells, the cutting goes through a complex path to the surface where some of the cuttings gravitate to the low side of the well. Reduction in any problem associated with improper cutting transport require good understanding in cutting transport mechanisms. This research focuses on calculating the minimum annular velocity of drilling fluid and minimum pump flow rate which is required to achieve hole- cleaning and lifting of the cutting to the surface, taking into consideration the main parameters that affect the coring capacity of the drilling fluid, for this purpose, data of a deviated well (X) located in Kurdistan region of Iraq is collected to determine slip velocity, annular velocity, critical flow rate and carrying capacity index taking in consideration the mud used and the angle of the deviation using the drilling formula spread sheet V1.6.

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Supriadi, Herman, et Rudy Sunarja Rivai. « Pengembangan Investasi Irigasi Kecil untuk Peningkatan Produksi Padi Mendukung Swasembada Beras ». Analisis Kebijakan Pertanian 16, n^o 1 (29 juin 2018) : 43. http://dx.doi.org/10.21082/akp.v16n1.2018.43-57.

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Community’s small irrigation investment gives impact on expansion of rice planted area and production. The study aims to assess impacts of small irrigation investment on rice planted area, production, and farmers’ income enhancement, and it was carried out during period of March to December 2013 in rainfed lowland areas in West Java, Central Java, and West Nusa Tenggara Provinces. Development of small irrigation based on community investment (SIBCI) is analyzed using Net Present Value, Incremental Benefit / Cost Ratio and Financial Internal Rate of Return approaches. Small irrigation was useful for improving rice planted area, production, and farmers’ income. Application of self-help water pumps was able to increase the area of wetland rice and cropping index. Small irrigation investments in both pump and gravity were financially feasible. The role of communities in small irrigation investment was significant despite financial limitation. Non-governmental funds allocated for pump irrigation network development were relatively small compared to that of gravity. Farmers’ participation in gravitational irrigation construction was relatively low and not all farmers became the P3A members. Small irrigation development requires synergy of social, physical, human, and natural capitals. Community’s participation in individual irrigation investment was relatively low contrary to that of managed by groups. The government need to collaborate with communities to manage water resources into community-based productive irrigation. AbstrakInvestasi irigasi kecil oleh masyarakat memberikan dampak terhadap peningkatan luas tanam dan produksi padi. Penelitian bertujuan mengkaji dampak irigasi kecil terhadap peningkatan luas tanam dan produksi padi. Penelitian dilakukan pada bulan Maret - Desember 2013 pada agro-ekosistem lahan tadah hujan di Jawa Barat, Jawa Tengah dan Nusa Tenggara Barat. Pengembangan irigasi kecil berbasis investasi masyarakat (IKBIM) dianalisis menggunakan Net Present Value, Incremental Benefit/Cost Ratio dan Financial Internal Rate of Return. Irigasi kecil sangat besar manfaatnya dalam meningkatkan perluasan tanam, produksi dan pendapatan petani. Penggunaan pompa secara swadaya mampu meningkatkan luas areal padi sawah dan indeks pertanaman. Investasi irigasi kecil baik pompa maupun gravitasi dinilai layak dilakukan. Peran masyarakat dalam investasi irigasi kecil sangat dominan, yang ditunjukkan dengan modal sosialnya yang tinggi, tetapi sering terbentur pada kemampuan finansial yang terbatas. Dana swadaya masyarakat yang dialokasikan untuk pengembangan jaringan irigasi pompa relatif kecil dibanding jaringan irigasi grafitasi. Partisipasi petani dalam pembangunan fisik untuk Irigasi Gravitasi masih rendah dan tidak semua petani menjadi anggota P3A. Pengembangan irigasi kecil memerlukan sinergi modal sosial, fisik, manusia dan alam. Tingkat partisipasi masyarakat kecil sekali untuk investasi irigasi yang dikelola secara perorangan (swasta). Sebaliknya, jika dikelola oleh kelompok maka partisipasi masyarakat cukup besar. Pemerintah perlu bekerjasama dengan masyarakat untuk membangun potensi sumber daya air menjadi irigasi pertanian produktif berbasis masyarakat.

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Tong, Zheming, Zhongqin Yang, Qing Huang et Qiang Yao. « Numerical Modeling of the Hydrodynamic Performance of Slanted Axial-Flow Urban Drainage Pumps at Shut-Off Condition ». Energies 15, n^o 5 (4 mars 2022) : 1905. http://dx.doi.org/10.3390/en15051905.

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Increasing extreme rainfall events caused by global climate change have had a significant impact on urban drainage systems. As a critical component of a pumping station, a large-scale slanted axial-flow pump (SAFP) featuring high specific speed plays a critical role in mitigating urban flooding and waterlogging. In this study, to reveal the transient characteristics of a SAFP at shut-off conditions, a computational fluid dynamics (CFD) based approach with dynamic mesh was proposed. Multiple shut-off conditions with various shut-down speeds of the sluice gate (SG) were modeled. Our analysis demonstrated that both the shut-off conditions and the slanted structure have conspicuous impacts on the hydrodynamic performance of a SAFP. Reducing the shut-down speed leads to a greater reverse flow rate and higher runner speed. The water hammer effect was simulated with different shut-down speeds, increasing the water head by 5.07–10.42 m, the axial force by 163.46–297.06 kN∙m, and the axial moment by 116.05–224.01 kN∙m. Compared with the axial direction, moments in the radial directions were found with more obvious oscillation as a result of stronger rotor–stator interaction. Due to the gravitational effect of the slanted structure, the fluctuation of the runner in vertical direction presented an off-axis characteristic compared with the horizontal one. As the SG speed increased, pressure fluctuations gradually decreased at various locations across the SAFP.

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Fomina, G. A., A. V. Salnikov et M. I. Koloteva. « STUDIES OF THE HUMAN CARDIOVASCULAR SYSTEM WITH THE USE OF ULTRASONIC METHODS IN SPACE MISSIONS : MAIN RESULTS AND FORWARD RESEARCHES ». Aerospace and Environmental Medicine 57, n^o 6 (2023) : 85–93. http://dx.doi.org/10.21687/0233-528x-2023-57-5-85-93.

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Integral ultrasonic investigations of cosmonauts' cardiovascular system (echocardiography, 2D-echography and dopplerography of vessels) at relative rest and studies of the hemodynamic reaction to LBNP (dopplerography of the brain and femoral arteries) were performed with participation of 26 cosmonauts before launch, during missions (8 to 438 days in duration) and after landing. Overall, more than 200 investigations were made at rest and 124 during the LBNP test. It was found that in microgravity the antigravity vascular tone regulation gradually becomes useless. Absence of gravitational stimuli leads to weakening of arterial resistance in all vascular regions below the heart level, blood displacement toward the areas with low vascular resistance, venostasis in the cervicocephalic and abdominal regions, and increase of leg veins capacity and compliance. However, the vital hemodynamic parameters, such as the pump function of the heart, blood supply to the brain, blood pressure and HR remain stable even during a long period in microgravity. Results of USI conducted during the LBNP test imitating the orthostatic blood distribution evidence that the femoral arteries resistance to blood displacement toward the leg arteries degrades progressively as mission continues. Degradation of the vasoconstrictive ability of leg arteries and increase of leg venous capacity and compliance are responsible for the orthostatic instability developing in space. Simultaneous recording of blood flow in the brain and femoral arteries is used to evaluate the reaction of hemodynamics to real and imitated orthostatic effects and to detect initial symptoms of orthostatic instability. The technique can be useful in designing novel methods for preventing orthostatic instability, and controlling their effectiveness.

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Alfian Hamsi et Tulus Burhanuddin Sitorus. « MECHANISM OF WATER DISTRIBUTION ON LEMON FARM LAND ». ABDIMAS TALENTA : Jurnal Pengabdian Kepada Masyarakat 3, n^o 2 (2 octobre 2019) : 118–24. http://dx.doi.org/10.32734/abdimastalenta.v3i2.2638.

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Pump is mechanical device to increase the pressure energy of a fluid. Generaly pumps are used to lift the water from low level to high level. These are of two types,namely reciprocating pumps and centrifugal pumps. On centrifugal pumps the centrifugal force or variation of pressure due to rotation is responsible for their operation or working. The program of community services as implementation of sciences and technology intended to introduced and give skill training about water supply units to the community at Desa Sempa jaya ,Kabupaten Deli-Karo. In this area the people have a problem about availibity of water for agricultute, when mountain Sinabung gets eruption the leave of plantation are covered with dust and damaged to citrus plants,in dry season orange plants lack of water even though the success of the harvest is very dependent on water. The program was carried out by designing, fabricating and erecting the unit of water supply,consist of deepwell pump,piping system, valve,tee,bent,tower tank and panel control. The result of this community services showed that the capacity of pumps are 6 liter/menit,head are 50-70 meter,power 2 HP,speed 1500 rpm.capacity of tower tank 5400 liter, the pump may supply the water to tower tank until full about 2 hours,and the farmer may use the water from the tower tank by gravitation about 3 days.

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Martinez, Miguel A. S., Nicholas C. Stone et Brian D. Metzger. « Orphaned exomoons : Tidal detachment and evaporation following an exoplanet–star collision ». Monthly Notices of the Royal Astronomical Society 489, n^o 4 (5 septembre 2019) : 5119–35. http://dx.doi.org/10.1093/mnras/stz2464.

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ABSTRACT Gravitational perturbations on an exoplanet from a massive outer body, such as the Kozai–Lidov mechanism, can pump the exoplanet’s eccentricity up to values that will destroy it via a collision or strong interaction with its parent star. During the final stages of this process, any exomoons orbiting the exoplanet will be detached by the star’s tidal force and placed into orbit around the star. Using ensembles of three- and four-body simulations, we demonstrate that while most of these detached bodies either collide with their star or are ejected from the system, a substantial fraction, $\sim 10{{\ \rm per\ cent}}$, of such ‘orphaned’ exomoons (with initial properties similar to those of the Galilean satellites in our own Solar system) will outlive their parent exoplanet. The detached exomoons generally orbit inside the ice line, so that strong radiative heating will evaporate any volatile-rich layers, producing a strong outgassing of gas and dust, analogous to a comet’s perihelion passage. Small dust grains ejected from the exomoon may help generate an opaque cloud surrounding the orbiting body but are quickly removed by radiation blow-out. By contrast, larger solid particles inherit the orbital properties of the parent exomoon, feeding an eccentric disc of solids that drains more gradually on to the star via Poynting–Robertson drag, and which could result in longer time-scale dimming of the star. For characteristic exomoon evaporation times of ∼105–106 yr, attenuation of the stellar light arising from one or more out-gassing exomoons provides a promising explanation for both the dipping and secular dimming behaviour observed from KIC 8462852 (Boyajian’s Star).

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Lee, Seungmi, Heui-Jin Park, Eunice B. Lee, Do Hyeon Lee, Dalwoong Choi et Kyung-Min Lim. « Disposition of Aerosols of Isothiazolinone-Biocides : BIT, MIT and OIT ». Toxics 10, n^o 12 (10 décembre 2022) : 770. http://dx.doi.org/10.3390/toxics10120770.

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Biocides are widely used in everyday life, and accordingly, human exposure to them is inevitable. Especially, the inhalational exposure of humans to biocides and resultant respiratory toxicity are gaining public interest due to the recent catastrophe associated with humidifier disinfectants. Aerosolized chemicals are subject to gravitational deposition and chemical degradation. Therefore, the characterization of the disposition of aerosols is essential to estimate the inhalational exposure to biocides. Here, we compared the disposition of aerosols of one of the commonly used biocide classes, isothiazolinone-based biocides, BIT, MIT, and OIT. An acrylic chamber (40 cm × 40 cm × 50 cm) was created to simulate the indoor environment, and a vacuum pump was used to create airflow (1 LPM). Biocides were sprayed from a vertical nebulizer placed on the ceiling of the chamber, and the distribution of particle sizes and volume was measured using the Optical Particle Sizer (OPS) 3330 device. During and after the aerosol spraying, airborne biocides and those deposited on the surface of the chamber were sampled to measure the deposition using LC-MS/MS. As a result, the broad particle size distribution was observed ranging from 0.3 to 8 μm during the nebulization. The inhalable particle faction (>2 μm) of the isothiazolinones was 32–67.9% in number but 1.2 to 6.4% in volume. Most of the aerosolized biocides were deposited on the chamber’s surface while only a minimal portion was airborne (<1%) after the nebulization. More importantly, significant amounts of MIT and OIT were degraded during aerosolization, resulting in poor total recovery compared to BIT (31%, 71% vs. 97% BIT). This result suggests that some isothiazolinones may become unstable during nebulization, affecting their disposition and human exposure significantly.

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Koskov, M. A., et A. F. Pshenichnikov. « Thermomagnetic convection in a hydrodynamic loop : the role of drop-like aggregates ». ВЕСТНИК ПЕРМСКОГО УНИВЕРСИТЕТА. ФИЗИКА, n^o 4 (2023) : 45–54. http://dx.doi.org/10.17072/1994-3598-2023-4-45-54.

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In order to clarify the effect of drop-like aggregates on the thermomagnetic convection of a fer-rofluid in a vertical hydrodynamic circuit (convective loop), two series of experiments were carried out, which differ in the dispersed composition of single-domain particles in the fluid. This particular geometry of the cavity with the ferrofluid was chosen because in a closed hydrodynamic circuit the best conditions are created for thermomagnetic convection and the heat transfer en-hancement, provided that a magnetic field is applied to the heated section of the circuit in one of its vertical sections. In this case, the field nonuniformity in the cross section of the channel form-ing the loop is sufficiently small, and the ponderomotive force acting on the liquid is directed along the tube. The heated section of the circuit, which is affected by a nonuniform magnetic field, ‘works’ as a kind of thermomagnetic pump and a circulation flow occurs in the circuit. In the first series of experiments, we used a ferrofluid containing a coarse fraction of particles capable of causing thermodynamic instability of the ferrofluid in a magnetic field (spinodal decomposition) and the formation of drop-like aggregates. The second series of experiments was carried out with a ferrofluid that had undergone magnetic separation and was free from coarse particles. It is shown that the results of convective experiments differ qualitatively depending on the disperse composi-tion of particles and the presence of drop-like aggregates. A ferrofluid with a coarse fraction com-pletely blocks the global circulation flow, including gravitational convection, while a separated ferrofluid, purified from large particles, increases the intensity of convection in a strong magnetic field and the integral heat flux by 6–7 times.

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Rakov, Ivan V. « METHODOLOGY FOR EVALUATING PARAMETERS OF THE ELECTRICAL COMPLEX «CABLE LINE — INDUCTION MOTOR» BASED ON POWER CONSUMPTION BALANCE ». Electrical and data processing facilities and systems 19, n^o 3 (2023) : 101–17. http://dx.doi.org/10.17122/1999-5458-2023-19-3-101-117.

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Relevance In the Russian Federation, 82 % of oil is produced using Electric Submersible Pumps (ESP), while only 63 % of wells are equipped with such pumps. Since more than half of the operating wells are equipped with ESP, developing methods to reduce operating costs for these wells is a rational and logical allocation of human, material, and financial resources. One method to increase the profitability of oil production from low- and medium-flow rate wells is to transition a well equipped with ESP from continuous operation to intermittent operation, specifically cyclic operation. Intermittent operation reduces energy consumption by up to 40 % and increases oil production by 3 % due to partial gravitational separation of the produced fluid during accumulation. However, the negative effect of transitioning to intermittent operation is reflected in the reduction of the average runtime before failure due to a decreased ESP hydroprotection resource, accelerated wear of the pump unit thrust bearings, and intermediate radial bearings. The cause of these negative effects is the increased vibration level during intensive startup. One way to address these issues is transitioning from the existing scalar open-loop control system to a vector sensorless control system for the ESP. To implement such a system, it is necessary to obtain information about the vector of the ESP state variables. A promising approach to obtaining information about the ESP state involves creating observers based on explicit mathematical models. To create an observer for the state variables, mathematical models for each component of the studied system must be developed and combined into a unified system. When measuring currents and voltages at the output of the step-up transformer, the studied system will be an electric complex «Cable Line — Induction Motor». To implement this observer, it is necessary to determine the parameters of the equivalent circuit of the studied complex. Based on the above, developing a methodology for identifying the parameters of the equivalent circuit of the electric complex «Cable Line — Induction Motor» when measuring currents and voltages on the surface is a timely and relevant task. Solving this task will create prerequisites for the implementation of a vector control system for the ESP, increasing the reliability of the ESP during intermittent operation, and consequently, increasing the profitability of oil production from low- and medium-flow rate oil wells. Aim of research To develop and experimentally confirm the effectiveness of a methodology for assessing the parameters of the electric complex «Cable Line — Induction Motor» based on the balance of consumed power. Research methods Analysis of literary sources, system analysis, mathematical modeling, experimental research. Results The effectiveness of the methodology for assessing the parameters of the electric complex «Cable Line — Induction Motor» based on the balance of consumed power has been experimentally tested and confirmed.

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Nådland, I. H., J. Wesche, D. D. Sheriff et K. Toska. « Does venous insufficiency impair the exercise-induced rise in arterial leg blood flow ? » Phlebology : The Journal of Venous Disease 26, n^o 8 (21 septembre 2011) : 326–31. http://dx.doi.org/10.1258/phleb.2011.010092.

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Objectives It has been shown that the leg muscle pump increases the immediate rise in arterial leg blood flow during upright exercise in healthy subjects. The present study is the first to investigate the muscle pump effect in exercise hyperaemia in patients with venous insufficiency, who should be lacking an optimally functioning muscle pump. Methods Any muscle pump effect is more pronounced in an upright position because of gravitation. The exercise-induced rise in femoral artery flow (FF) (ultrasound Doppler) was thus compared in the supine and 30° head-up tilted position in 10 patients. Results Neither the transient nor the steady-state rise in FF showed any difference between positions. This is in contrast to the previous findings in healthy subjects, where the transient rise in FF was larger in the tilted position. Conclusion The muscle pump effect in exercise hyperaemia seems to be reduced or lacking in these patients.

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