233 research outputs found

    Energy-efficient control of pump units based on neural-network parameter observer

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    An observer based on an artificial neural network was designed. The observer determines the pumping unit performance depending on the operating point. Determination is based on the measured technological coordinates of the system and the pressure of the turbomechanism. Three neural networks were designed for three types of the productivity observer. The developed observer was investigated by the simulation method within different variations of disturbing actions, such as hydraulic resistance of the hydraulic system and geodetic pressure. A comparative analysis of three types of the productivity observer, built with using the pressure and different signals of the system with arbitrary change of hydraulic resistance was given. By the use of the pump unit efficiency observer, in addition to the results presented earlier, the efficiency of the productivity observer, which built with using different sensors, in water supply systems with two series-connected pump units, operating for filling the large tank, is researched. In the water supply system one pump speed is regulated, the other is unregulated. References 14, figures 5

    Over-the-scope clip (OTSC (R)) closure of a recto-acetabular fistula

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    A 25-year-old male Syrian refugee presented in our hospital with recurrent hip infections after having undergone hip arthroplasty abroad following destruction of his right hip joint by shell splinters in the Syrian civil war. The patient underwent hip arthroplasty revision with implantation of a cement spacer. CT-scan with rectal contrast media filling revealed a rectoacetabular fistula. Consecutively, the patient underwent ileostomy formation. The fistula was then successfully closed by endoscopic over-the-scope clipping (OTSC (R)). Fistulas between intestines and joints rarely develop and in the few cases published mostly extensive abdominal rescue surgery has been performed. Here, we present a case of a traumatic rectoacetabular fistula that was successfully closed by OTSC. This innovative method could represent a safe and suitable option to effectively close fistulas between joints and intestines thereby avoiding extensive rescue surgery with bowel resection or permanent ostomy

    Identifiable Acetylene Features Predicted for Young Earth-like Exoplanets with Reducing Atmospheres Undergoing Heavy Bombardment

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    The chemical environments of young planets are assumed to be largely influenced by the impacts of bodies lingering on unstable trajectories after the dissolution of the protoplanetary disk. We explore the chemical consequences of impacts within the context of reducing planetary atmospheres dominated by carbon monoxide, methane, and molecular nitrogen. A terawatt high-power laser was selected in order to simulate the airglow plasma and blast wave surrounding the impactor. The chemical results of these experiments are then applied to a theoretical atmospheric model. The impact simulation results in substantial volume mixing ratios within the reactor of 5% hydrogen cyanide (HCN), 8% acetylene (C2H2), 5% cyanoacetylene (HC3N), and 1% ammonia (NH3). These yields are combined with estimated impact rates for the early Earth to predict surface boundary conditions for an atmospheric model. We show that impacts might have served as sources of energy that would have led to steady-state surface quantities of 0.4% C2H2, 400 ppm HCN, and 40 ppm NH3. We provide simulated transit spectra for an Earth-like exoplanet with this reducing atmosphere during and shortly after eras of intense impacts. We predict that acetylene is as observable as other molecular features on exoplanets with reducing atmospheres that have recently gone through their own "heavy bombardments," with prominent features at 3.05 and 10.5 μm

    Time-resolved XUV Opacity Measurements of Warm-Dense Aluminium

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    The free-free opacity in plasmas is fundamental to our understanding of energy transport in stellar interiors and for inertial confinement fusion research. However, theoretical predictions in the challenging dense plasma regime are conflicting and there is a dearth of accurate experimental data to allow for direct model validation. Here we present time-resolved transmission measurements in solid-density Al heated by an XUV free-electron laser. We use a novel functional optimization approach to extract the temperature-dependent absorption coefficient directly from an oversampled pool of single-shot measurements, and find a pronounced enhancement of the opacity as the plasma is heated to temperatures of order the Fermi energy. Plasma heating and opacity-enhancement is observed on ultrafast time scales, within the duration of the femtosecond XUV pulse. We attribute further rises in the opacity on ps timescales to melt and the formation of warm-dense matter

    Examining smoking-induced differential gene expression changes in buccal mucosa

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    <p>Abstract</p> <p>Background</p> <p>Gene expression changes resulting from conditions such as disease, environmental stimuli, and drug use, can be monitored in the blood. However, a less invasive method of sample collection is of interest because of the discomfort and specialized personnel necessary for blood sampling especially if multiple samples are being collected. Buccal mucosa cells are easily collected and may be an alternative sample material for biomarker testing. A limited number of studies, primarily in the smoker/oral cancer literature, address this tissue's efficacy as an RNA source for expression analysis. The current study was undertaken to determine if total RNA isolated from buccal mucosa could be used as an alternative tissue source to assay relative gene expression.</p> <p>Methods</p> <p>Total RNA was isolated from swabs, reverse transcribed and amplified. The amplified cDNA was used in RT-qPCR and microarray analyses to evaluate gene expression in buccal cells. Initially, RT-qPCR was used to assess relative transcript levels of four genes from whole blood and buccal cells collected from the same seven individuals, concurrently. Second, buccal cell RNA was used for microarray-based differential gene expression studies by comparing gene expression between a group of female smokers and nonsmokers.</p> <p>Results</p> <p>An amplification protocol allowed use of less buccal cell total RNA (50 ng) than had been reported previously with human microarrays. Total RNA isolated from buccal cells was degraded but was of sufficient quality to be used with RT-qPCR to detect expression of specific genes. We report here the finding of a small number of statistically significant differentially expressed genes between smokers and nonsmokers, using buccal cells as starting material. Gene Set Enrichment Analysis confirmed that these genes had a similar expression pattern to results from another study.</p> <p>Conclusions</p> <p>Our results suggest that despite a high degree of degradation, RNA from buccal cells from cheek mucosa could be used to detect differential gene expression between smokers and nonsmokers. However the RNA degradation, increase in sample variability and microarray failure rate show that buccal samples should be used with caution as source material in expression studies.</p

    Логічний синтез дискретних систем автоматичного керування при використанні програмованих реле низького рівня

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    Логічний синтез дискретних систем автоматичного керування при використанні програмованих реле низького рівня = Logical synthesis of discrete automatic control systems using low-level programmed relays / С. О. Бур’ян, М. В. Печеник, Г. Ю. Землянухіна, І. С. Єпіфанцев // Зб. наук. пр. НУК. – Миколаїв : НУК, 2021. – № 1 (484). – С. 54–60.Анотація. Для керування комплексними системами автоматизації, як правило, використовуються інтелектуальні промислові контролери, які мають досить складну структуру і високі вартісні характеристики. Разом із тим для локальних систем керування, які забезпечують виконання певної виробничої задачі або самостійно, або в рамках загального технологічного циклу, досить перспективним є використання програмних реле низького рівня, яким властиві невисока вартість, простота в програмуванні, зручність в експлуатації. Однак недоліком зазначених реле можна відзначити обмежену кількість комірок пам’яті й елементів, які записуються в програмі, що у свою чергу призводить до використання більш дорогих контролерів для локальних систем автоматизації з великою кількістю станів. Мета. Вдосконалення методу синтезу логічних схем на основі графопереходів для використання його під час розроблення дискретних систем керування технологічними процесами з великою кількістю станів за умови технічної реалізації програми на логічних реле низького класу. Методика. Вдосконалення методу синтезу полягає в перетворенні громіздкого графопереходу, який описує переходи між станами дискретної схеми в ланцюг із декількох графопереходів, кожен з яких описує частину станів системи автоматизації або технологічного процесу. Останній сигнал, який переводить поточний графоперехід у вихідний стан, є одночасно першим сигналом наступного графопереходу. Це у свою чергу знімає обмеження застосування в складних системах автоматизації логічних реле низького рівня, оскільки зменшується кількість комірок пам’яті, необхідних для написання програми. Результати. Запропонована модифікація передбачає, що замість одного графопереходу, що описує всі стани системи автоматизації, застосовується ланцюг із невеликих графопереходів, які послідовно переходять з одного на інший. При цьому зменшується кількість кон’юнктивних членів у кожному рівнянні, що дозволяє використовувати отримані рівняння для складання програм для логічних програмованих реле, що мають обмеження за кількістю комірок пам’яті та кількістю елементів, що записуються в програмі. Наукова новизна. Вдосконалено метод синтезу дискретних систем автоматизації на основі графопереходів, який полягає в перетворенні громіздкого графопереходу, що описує переходи між станами дискретної схеми, в ланцюг із декількох графопереходів, кожен з яких описує частину станів системи автоматизації або технологічного процесу. Практична значимість. Вдосконалений метод має елементи уніфікації, і його можна використовувати для синтезу логічних рівнянь, що описують системи автоматичного керування, які працюють за лінійним алгоритмом, тобто схема послідовно переходить з одного стану в інший, що є характерною рисою також і для електромеханічних систем механізмів загальнопромислового призначення циклічного режиму роботи.Abstract. To control complex automation systems, as a rule, intelligent industrial controllers are used, which have a rather complex structure and high cost characteristics. However, for local control systems that provide a certain production task either independently or within the general technological cycle is quite promising to use low-level software relays, which are characterized by low cost, ease of programming, ease of operation. However, the disadvantage of these relays is the limited number of memory cells and elements that are recorded in the program, which in turn leads to the use of more expensive controllers for local automation systems with a large number of states. Purpose. Improving the method of synthesis of logic circuits based on graph transitions for its use in the development of discrete process control systems with a large number of states under the condition of technical implementation of the program on low-class logic relays. Method. The improvement of the synthesis method is to transform a bulky graph transition, which describes the transitions between the states of a discrete circuit into a chain of several graph transitions, each of which describes part of the states of the automation system or process. The last signal that converts the current graph transition to the initial state is also the first signal of the next graph transition. This in turn removes the limitations of using low-level logic relays in complex automation systems, as it reduces the number of memory cells required to write a program. Results. The proposed modification assumes that instead of one graph transition, which describes all the states of the automation system, a chain of small graph transitions is used, which successively pass from one to another. This reduces the number of conjunctive terms in each equation, which allows you to use the resulting equations to compile programs for logic programmable relays, which are limited by the number of memory cells and the number of elements recorded in the program. Scientific novelty. The method of synthesis of discrete automation systems based on graph transitions is improved, which consists in transforming a bulky graph transition describing transitions between states of a discrete circuit into a chain of several graph transitions, each of which describes a part of automation system or process states. Practical importance. The advanced method has elements of unification and can be used to synthesize logical equations describing automatic control systems that operate on a linear algorithm, i.e. the circuit sequentially passes from one state to another, which is also a characteristic feature of electromechanical systems of general industrial mechanisms of cyclic mode work

    Control system for ion Penning traps at the AEgIS experiment at CERN

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    The AEgIS experiment located at the Antiproton Decelerator at CERN aims to measure the gravitational fall of a cold antihydrogen pulsed beam. The precise observation of the antiatoms in the Earth gravitational field requires a controlled production and manipulation of antihydrogen. The neutral antimatter is obtained via a charge exchange reaction between a cold plasma of antiprotons from ELENA decelerator and a pulse of Rydberg positronium atoms. The current custom electronics designed to operate the 5 and 1 T Penning traps are going to be replaced by a control system based on the ARTIQ & Sinara open hardware and software ecosystem. This solution is present in many atomic, molecular and optical physics experiments and devices such as quantum computers. We report the status of the implementation as well as the main features of the new control system

    Development of a detector for inertial sensing of positronium at AEgIS (CERN)

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    The primary goal of the AEgIS collaboration at CERN is to measure the gravitational acceleration on neutral antimatter. Positronium (Ps), the bound state of an electron and a positron, is a suitable candidate for a force-sensitive inertial measurement by means of deflectometry/interferometry. In order to conduct such an experiment, the impact position and time of arrival of Ps atoms at the detector must be detected simultaneously. The detection of a low-velocity Ps beam with a spatial resolution of (88 ± 5) μm was previously demonstrated [1]. Based on the methodology employed in [1] and [2], a hybrid imaging/timing detector with increased spatial resolution of about 10 μm was developed. The performance of a prototype was tested with a positron beam. The concept of the detector and first results are presented

    Positronium laser cooling via the 13S1^3S-23P2^3P transition with a broadband laser pulse

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    We report on laser cooling of a large fraction of positronium (Ps) in free-flight by strongly saturating the 13S1^3S-23P2^3P transition with a broadband, long-pulsed 243 nm alexandrite laser. The ground state Ps cloud is produced in a magnetic and electric field-free environment. We observe two different laser-induced effects. The first effect is an increase in the number of atoms in the ground state after the time Ps has spent in the long-lived 33P3^3P states. The second effect is the one-dimensional Doppler cooling of Ps, reducing the cloud's temperature from 380(20) K to 170(20) K. We demonstrate a 58(9) % increase in the coldest fraction of the Ps ensemble.Comment: 6 pages, 5 figure
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