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2022 ◽  
Author(s):  
Emmanuel Duplay ◽  
Zhuo Fan Bao ◽  
Sebastian Rodriguez Rosero ◽  
Arnab Sinha ◽  
Andrew Jason Higgins

The application of directed energy to spacecraft mission design is explored using rapid transit to Mars as the design objective. An Earth-based laser array of unprecedented size (10-m diameter) and power (100 MW) is assumed to be enabled by ongoing developments in photonic laser technology. A phased-array laser of this size and incorporating atmospheric compensation would be able to deliver laser power to spacecraft in cislunar space, where the incident laser is focused into a hydrogen heating chamber via an inflatable reflector. The hydrogen propellant is then exhausted through a nozzle to realize specific impulses of 3000 s. The architecture is shown to be immediately reusable via a burn-back maneuver to return the propulsion unit while still within range of the Earth-based laser. The ability to tolerate much greater laser fluxes enables realizing the combination of high thrust and high specific impulse, making this approach favorable in comparison to laser-electric propulsion and occupying a parameter space similar to gas-core nuclear thermal rockets (without the requisite reactor). The heating chamber and its associated regenerative cooling and propellant handling systems are crucial elements of the design that receive special attention in this study. The astrodynamics and the extreme aerocapture maneuver required at Mars arrival after a 45-day transit are also analyzed in detail. The application of laser-thermal propulsion as an enabling technology for other rapid transit missions in the solar system and beyond is discussed.


2021 ◽  
Vol 9 ◽  
Author(s):  
Jianhua Qin ◽  
Jing Zhang ◽  
Shijie Zhu ◽  
Yingwei Wang ◽  
Tao Wan

Field observations discern that the oil production rate decreases substantially and water cut increases rapidly with the increase of steam injection cycles. Compared with steam drive, the advantage of flue gas (also called multi-component thermal gas) co-injection with steam is that flue gas can increase the reservoir pressure and expand the heating chamber. In this paper, the flue gas generated by fuel burning in the field was injected with steam to improve heavy oil recovery. This technique was investigated in the large laboratory 3D model and implemented in the field as well. The huff-n-puff process efficiency by flue gas, steam, and flue gas–steam co-injection was compared in the experiments. The field practice also demonstrated that the addition of non-condensable gas in the steam huff-n-puff process recovered more oil than steam alone. The temperature profile in the wellbore with flue gas injection is higher than that with steam injection since the low thermal conductivity of N2 reduces the heat loss. With the increase of stimulation cycles, the incremental oil recovery by flue gas injection declines significantly.


2021 ◽  
Vol 8 ◽  
Author(s):  
Ruchira Nandasiri ◽  
Afra Imran ◽  
Usha Thiyam-Holländer ◽  
N. A. Michael Eskin

RapidOxy® 100 is an automated instrument originally designed for measuring the oxidative stability of both solid and liquid samples. The compact and portable design of RapidOxy® 100, and its built-in pressurized heating chamber, provides a suitable environment for studying processing conditions. The feasibility of using oxygen or an inert atmosphere provides the ideal environment to study the effect of dry heat pre-treatment on canola antioxidants. The current study used RapidOxy® 100 to examine the impact of pressurized dry heat pre-treatment, under nitrogen, on the ultrasonic extraction of phenolic compounds. The effect of different pre-treatment temperature-time combinations of 120, 140, 160, and 180°C for 2, 5, 10, 15, and 20 min on the subsequent extraction of canola phenolic compounds was examined. The major sinapates identified by HPLC were sinapine, sinapic acid, and canolol. The optimum RapidOxy® condition for the maximum recovery of canolol was 160°C for 10 min. RapidOxy® 100 proved to be a novel and versatile instrument for enhancing the extraction of phenolic compounds.


Nafta-Gaz ◽  
2021 ◽  
Vol 77 (7) ◽  
pp. 480-489
Author(s):  
Sylwia Jędrychowska ◽  

The knowledge of the water content of various petroleum products, including lubricating oils, additives and various innovative products, is important from the point of view of manufacturing, purchasing or selling them, due to the impact on their quality and performance characteristics. In the case of lubricating oils, the presence of water can lead to premature corrosion and wear, the formation of deposits, which leads to reduced lubrication and premature clogging of filters, reduced action of additives or undesirable bacterial growth. The article presents the study on the selection of optimal conditions for the determination of water content by coulometric Karl-Fischer titration with evaporation in lubricating oils. The tests were carried out using a coulometer with a titration cell without a diaphragm by Metrohm, 917 Coulometer model with an automatic sample feeder equipped with a heating chamber 885 Compact Oven Sample Changer. Various types of lubricating oils were selected for testing, namely engine oils of different viscosity classes (5W/40, 10W/40, 15W/40, 5W/30), gear oil, hydraulic oil, turbine oil, base oil and hydraulic fluid. All selected samples of lubricating oils were tested in four different measuring conditions: 110°C and 20 ml/min; 150°C and 50 ml/min, 180°C and 50 ml/min and 150°C and 70 ml/min. It was found that for all the lubricating oils, the best results were obtained with a furnace temperature setting of 150°C and a carrier gas flow of 50 ml/min or 70 ml/min. The influence of various factors, such as the sample weight, the furnace temperature, the carrier gas flow velocity on the test course and the analysis speed, was determined. Increased carrier gas flow of up to 70 ml/min does not shorten the analysis time. In some cases, an increase in the oven temperature may speed up the analysis, but this is quite risky for some samples that decompose at given temperature. It is therefore safer to conduct the test at an oven temperature of 150°C. The speed of analysis is most influenced by an appropriate selection of the sample quantity under analysis. Depending on the water content in the tested sample, the appropriate sample weight should be selected. It should be small enough not to excessively extend the analysis, but also large enough that the amount of titrated water is at least twice as large as in the blank.


Author(s):  
Julia de Oliveira NEVES ◽  
Franciele de Oliveira DIAS ◽  
Laís Stabile PRONI ◽  
Maria Letícia Oliveira e FREITAS ◽  
Carolina Simonetti LODI ◽  
...  

O objetivo desse trabalho foi avaliar a atividade antimicrobiana do hidróxido de cálcio (HC) associada a nanopartículas de prata (Ag-NPs) sobre biofilme de Enterococus faecalis. 144 espécimes de dentina foram inoculadas em placas contendo meio de cultura com E. faecalis (ATCC 29212) para a formação de biofilme.  As medicações foram preparadas na proporção de 1:1 de HC e soro estéril e, em seguida, pesada e adicionada às concentrações de Ag-NPs 2,5%, 5% e 10%. Decorridos 14 dias, os espécimes foram lavados, transferidos para uma nova placa onde as medicações foram colocadas sobre o biofilme e deixados em estufa a 37°C por 2, 7 e 14 dias. Espécimes sem tratamento foram usados como controle negativo. Após cada tempo experimental, os espécimes foram lavados, agitados, diluídos e plaqueados em triplicata em M-Enterococcus. As unidades formadoras de colônia foram contadas e analisadas estatisticamente (p<0,05). Os resultados mostraram que não houve diferença estatística entre a medicação de HC e o grupo controle nos períodos de 2 e 7 dias, mesmo quando associados às diferentes concentrações da Ag-NPs. Após 14 dias de contato direto com a medicação, houve uma redução do biofilme bacteriano nos grupos de HC sozinho e associado à prata, quando comparado com o grupo controle, mas nenhuma diferença foi observada entre os grupos de HC. Diante dos resultados, podemos concluir que a associação da Ag-NPs não contribuiu para a atividade antimicrobiana do HC.   ANTIMICROBIAL ANALYSIS OF THE USE OF SILVER NANOPARTICLES WITH CALCIUM HYDROXIDE AS INTRACANAL MEDICATION   ABSTRACT This paper aims at evaluating the antimicrobial activity of calcium hydroxide (CH) in association with silver nanoparticles (AgNPs) over the Enterococus faecalis biofilm.144 dentine specimens were inoculated in plates containing culture medium with E. faecalis (ATCC 29212) to biofilm formation. Medication was prepared in proportion 1:1 of CH and sterile serum, then weighted and added to 2,5%, 5%, and 10% AgNPs concentrations. No earlier than 14 days, the specimens were washed, transferred to a new plate where medication was applied over the biofilm and rested in heating chamber at 37 ºC during 2, 7, and 14 days. Specimens with no treatment were used as a negative control. After each trial time, the specimens were washed, mixed, diluted, and plated in triplicate at M-Enterococcus. The colony-forming units were counted and statistically analyzed (p<0,05). The results showed that there was no statistical difference between CH medication and the group of control during the period of 2 and 7 days, even when they were associated with different concentrations of AgNPs. After 14 days of direct contact with the medication, there was a reduction of the bacterial biofilm in the groups of CH itself and associated with silver, when compared to the control group, but no difference was observed in the group of CH. In view of the results, we can conclude that the association of AgNPs does not contribute to the antimicrobial activity of the CH.   Keywords: Antibacterial.  Silver. Endodontics.  Enterococcus faecalis.


Author(s):  
N. G. Kulneva ◽  
V. A. Fedoruk ◽  
N. A. Matvienko ◽  
E. M. Ponomareva

The article discusses the concepts of continuous vacuum apparatus operation: vertical VKT (VKT – Verdampfungs-Kristallisations-Turm) and horizontal cascade of VKH vacuum apparatus (VKH —horizontal vacuum pan) from BMA (Germany). The advantages and features of the vertical continuous vacuum apparatus VKT are shown, as well as the possibilities for increasing the efficiency of the product department of sugar factories. Thanks to the special design of the crystallization chambers, the low massecuite level above the heating chamber and the use of mechanical stirrers in each chamber, the VKT apparatus can operate without difficulty with a very small temperature difference between heating steam and massecuite, as well as with an absolute heating steam pressure well below 1 bar. With optimal use of VKT vacuum apparatus, a variety of energy-saving schemes can be implemented, for example, double-effect evaporation in the crystallization section. Part of the secondary crystallization steam is used to heat one of the VKT units, which saves the heating steam of the evaporator unit used for this purpose. With an increase in the productivity of the sugar factory, it is possible to quickly equip the VKT apparatus with an additional chamber. The device works continuously throughout the season, especially with products with massecuite purity of more than 94%. The chambers are cleaned without stopping the entire apparatus. The boiling of massecuite of all stages of crystallization in VKT devices ensures a uniform operating mode of the food compartment, allows to achieve an increase in sugar yield and helps to reduce steam consumption at the plant.


2021 ◽  
Vol 86 (5-2) ◽  
Author(s):  
Askar Artikov ◽  
Zulhumar Masharipova ◽  
Marziya Karimullaeva
Keyword(s):  

2021 ◽  
pp. 004051752110106
Author(s):  
Jumei Zhao ◽  
Hongtao Zhou ◽  
Huizhen Ke ◽  
Xueliang Xiao ◽  
Qingqing Wang ◽  
...  

In this work, a polypropylene (PP) porous film was made-up by melt electrospinning. The fibrous film was coated by a superthin layer of silicon dioxide (SiO2) gel. The surface morphology of the SiO2 gel was decoded by scanning electron microscopy and atomic force microscopy. The SiO2 gel interface with film, as well as its crystallinity, were characterized by Fourier transform infrared spectroscopy, energy dispersive spectroscopy, and X-ray diffraction. The PP composite film's thermomechanical properties were studied through thermal shrinkage, thermal gravimetric analysis, dynamic mechanical analysis, and an Instron tensile machine with a heating chamber. The results showed that the coated SiO2 gel network could effectively reduce the PP film's thermal shrinkage by 48.5% without change of crystallinity. The coated SiO2 gel is capable of enlarging the decomposition temperature range and the storage modulus of the PP film. Meanwhile, it was discovered that, along with the increase of measured temperature, the loads on both pure PP film and PP/SiO2 gel film decreased under a constant strain, or the tensile strain of both of them was enhanced under the same load. The solid gel network endows the PP electrospun film with relatively higher thermal safety.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Eshan Agrawal ◽  
Vinod Tungikar

Purpose Aluminium matrix composites are subjected to wear as well as higher temperature applications such as pistons, cylinder heads and blocks for car engines. Therefore, it is important to evaluate the performance of aluminium metal matrix composite at elevated temperature. Design/methodology/approach In the present work wear performance of Al-TiC composite with 7.5% reinforcement of TiC powder is carried out at elevated temperature. The composite specimens are prepared with the help of centrifugal casting method to get the large segregation of reinforcement on the outer layer of the composite which is subjected to wear. Taguchi method is used for preparing design of experiments. Findings The wear test is performed on DUCOM pin on disc setup having the heating chamber facility. The results of wear test are analysed with the help of MINITAB 19 software. The results show that temperature has dominant effect on the wear rate. The mathematical model through regression is predicted for wear rate and coefficient of friction. The study of worn-out surface is performed with the help of scanning electron microscope. The micrographs show that the type of wear is changes from abrasive to severe wear and some delamination. Originality/value The experiments are conducted as per ASTM standards. The results give the mathematical equation for wear rate and coefficient of friction at elevated temperatures.


Author(s):  
Anatoly Elshin ◽  
◽  
Vyacheslav Kozhukhov ◽  
Petr Elshin ◽  
◽  
...  

To reduce production costs in the design and creation of an inductive-conductive heater (ICH), it is necessary to carry out a preliminary calculation as accurately as possible. This is possible when using the most approximate electrical circuit for replacing the ICH to a real object. It becomes possible to assess the work of the ICH in various operating conditions, including emergency conditions, using simpler modeling. An inductive-conductive heater transformertype is a three-rod W-shaped magnetic circuit with primary windings, which are covered by a heat exchanger (HE) of three concentric systems of electrically conductive cylinders with an internal slotted channel for the coolant. The energy from the mains supply is inductively transferred to the heat exchanger through the air gap by means of the primary winding. The secondary circuit of an electromagnetic device is a heat exchanger in which electrical energy is converted into heat. The heat flux from the heated cylindrical walls of the HE conductively heats the coolant circulating in the system to the required temperature. The large surface area of the HE allows you to avoid its overheating in relation to the coolant, which has a positive effect during the operation of the ICH in heating and hot water supply systems, significantly reducing the deposition of water impurities on the walls of the HE. The service life of the device is increased to 100 thousand hours or more. In the work, the synthesis of elements of the ICH equivalent circuit is carried out and the results of calculating the characteristics of the stationary mode of a number of products are presented. The equivalent circuit allows you to simulate electromagnetic processes in devices of different power, voltage and industrial frequencies in the range of 50…1000 Hz. If the configuration of the heating chamber (secondary circuit) is changed, the parameters of the elements of the equivalent circuit are adjusted without changing the general construction algorithm. For new products of inductive-conductive heating, there are no bibliographic data for calculating the elements of the equivalent circuit, especially regarding the formation of the replacement circuit of the secondary circuit, determined by the design of the heating chamber. To fill this gap, the authors have done this work.


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