scholarly journals Marine diesel engine – a novel approach of indicated power determination and related uncertainty level

2017 ◽  
Vol 168 (1) ◽  
pp. 15-20
Author(s):  
Przemysław KOWALAK ◽  
Stefan ŻMUDZKI ◽  
Tadeusz BORKOWSKI

A proposal of a new method for marine engine indicated power determination, based on direct piston position, instead of crankshaft angular position measurement, was presented. With the aid of bond graph theory, it was proved, that the new method is equivalent to conventional method. To verify hypothesis, that the new method has potential of determined indicated power uncertainty reduction, simulated calculations were carried out. Results of calculations for two marine diesel engines: medium-speed, four stroke and slowspeed two stroke type, at assumption of engine crankshaft constant speed, were compared with results obtained by a conventional method. Data, collected by means of a typical portable, industrial, digital indicator on engines in service, were used for simulation. The uncertainties of engines indicated power determined by means of two methods were analysed. The indicated power uncertainty, achieved for conventional method, was nearly twice higher than for new proposed method. Finally, uncertainty structure was analysed and evaluated for both: new and conventional method of engine indicated power determination.

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4644 ◽  
Author(s):  
Naus ◽  
Marchel ◽  
Szymak ◽  
Nowak

The paper presents the results of research on assessing the accuracy of angular position measurement relative to the sea horizon using a camera mounted on an unmanned bathymetric surveying vehicle of the Unmanned Surface Vehicle (USV) or Unmanned Aerial Vehicle (UAV) type. The first part of the article presents the essence of the problem. The rules of taking the angular position of the vehicle into account in bathymetric surveys and the general concept of the two-camera tilt compensator were described. The second part presents a mathematical description of the meters characterizing a resolution and a mean error of measurements, made on the base of the horizon line image, recorded with an optical system with a Complementary Metal-Oxide Semiconductor (CMOS) matrix. The phenomenon of the horizon line curvature in the image projected onto the matrix that appears with the increase of the camera height has been characterized. The third part contains an example of a detailed analysis of selected cameras mounted on UAVs manufactured by DJI, carried out using the proposed meters. The obtained results including measurement resolutions of a single-pixel and mean errors of the horizon line slope measurement were presented in the form of many tables and charts with extensive comments. The final part presents the general conclusions from the performed research and a proposal of directions for their further development.


Author(s):  
Л.Б. Леонтьев ◽  
Н.П. Шапкин ◽  
А.Л. Леонтьев ◽  
В.Н. Макаров ◽  
А.В. Арон

Повышение долговечности трибосопряжений судовых дизелей, определяющих их ресурс, представляет собой актуальнейшую проблему, обусловленную как безопасностью мореплавания, так и экономическими факторами. Основной причиной отказов коленчатых валов двигателей, определяющих необходимость капитального ремонта, является износ шеек. Решение проблемы повышения износостойкости и, соответственно, долговечности связано с применением трибоактивных присадок в смазку. Несмотря на глубокие и обстоятельные исследования в области применения органо-неорганических материалов для использования в качестве присадок в моторное масло для повышения долговечности трибоузлов осуществить выбор оптимального материала для конкретных условий практически невозможно, так как исследования выполнены для различных условий эксплуатации и по различным методикам. Цель работы – разработка триботехнической присадки к моторным маслам, обеспечивающей повышение надежности и эффективности технической эксплуатации судовыхсреднеоборотных дизелей путем формирования тонкопленочного металлокерамического покрытия на поверхностях трения стальных деталей трибоузлов, позволяющего получить оптимальный комплекс параметров материала износостойкого покрытия. В работе представлены исследования эксплуатационных свойств присадок в моторное масло 17 органо-неорганических триботехнических материалов 4 групп — природные и искусственные полимеры, из которых были изготовлены свыше 20 композиций и композитов. Установлено, что наиболее перспективным является использование нанокомпозитов на основе вермикулита, модифицированного кислотой, в качестве присадок в моторное масло, так как они обладают минимальными коэффициентом трения при граничной смазке (0,007–0,014) а также высокой износостойкостью стали 40Х и обеспечивают минимальную величину скорости изнашивания вкладыша подшипника, благодаря чему повышается ресурс трибосопряжения более, чем в 3 раза, и соответственно снижаются эксплуатационные расходы. Increasing the durability of the tribo-couplings of marine diesel engines, which determine their resource, is an urgent problem due to both the safety of navigation and economic factors. The main reason for engine crankshafts failures, which determine the need for major repairs, is the wear of the necks. The solution to the problem of increasing wear resistance and, accordingly, durability is associated with the use of triboactive additives in the lubricant. Despite in-depth and thorough research in the field of application of organo-inorganic materials for use as additives in engine oil to increase the durability of tribo-nodes, it is almost impossible to choose the optimal material for specific conditions, since the studies were carried out for various operating conditions and according to various methods. The purpose of the work is to develop a tribotechnical additive to motor oils that provides an increase in the reliability and efficiency of technical operation of medium-speed marine diesel engines by forming a thin-film metal-ceramic coating on the friction surfaces of steel parts of tribo-nodes, which allows to obtain an optimal set of parameters of the wear-resistant coating material. The paper presents studies of the operational properties of additives in engine oil of 17 organo-inorganic tribotechnical materials of 4 groups — natural and artificial polymers, from which more than 20 compositions and composites were made. It has been established that the most promising is the use of nanocomposites based on vermiculite modified with acid as additives in engine oil, since they have a minimum coefficient of friction with boundary lubrication (0.007-0.014) as well as high wear resistance of 40X steel and provide a minimum wear rate of the bearing liner, thereby increasing the tribo-tension life by more than 3 times, and, accordingly, operating costs are reduced.


Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4007 ◽  
Author(s):  
Qian Li ◽  
Jiabin Wu ◽  
Yunshan Chen ◽  
Jingyuan Wang ◽  
Shijie Gao ◽  
...  

In this paper, we propose a new method to improve the position measurement accuracy for Laguerre-Gaussian beams on a quadrant detector (QD). First, the error effects of the detector diameter and the gap size are taken into account, and the position error compensation factor is introduced into the conventional formula. Then, in order to reduce the number of parameters, the concept of effective radius is proposed. Thus, a new analytical expression is obtained with a best fit using the least square method. It is verified by simulation that this approach can reduce the maximum error by 97.4% when the beam radius is 0.95 mm; meanwhile, the root mean square errors under different radii are all less than 0.004 mm. The results of simulation show that the new method could effectively improve the accuracy of the QD measurement for different radii. Therefore, the new method would have a good prospect in the engineering practice of beam position measurements.


2021 ◽  
Vol 36 (5) ◽  
pp. 596-602
Author(s):  
Veli Voipio

In this article, I propose a new method for calculating and visualizing the pulse radiation within the depth range commonly used by Ground Penetrating Radar (GPR). The text describes the method and illustrates the propagation with several examples. One conventional method is also applied for a quick comparison. The method can be used to optimize GPR antennas and transmit pulse shapes.


2019 ◽  
Author(s):  
Shangyingying Li ◽  
Yanzhe Tan ◽  
Fei Yang ◽  
Lifei Liu ◽  
Shengfen Tu

Abstract Background Caudal block is widely used in paediatric anaesthetic practice. Many angles for needle insertion were compared to find a optimal angle during caudal block with high successful caudal injection and minimal risk of complications. The aim of this study is to evaluate the safety and effectivity of a new method of needle insertion at an angel of 90°to the apex of the sacral hiatus for caudal block in newborns. Methods Sixty patients were included in our study, aged 0 to 28 days, posted for inguinal hernia surgery, randomly divided into two groups: a conventional method (CM) group and a new method (NM) group. In both groups, 1 ml∙kg-1 0.5% lignocaine at a rate of approximately 0.5 ml∙s-1 was given for caudal blocks after anaesthesia, and ultrasonographic observation of local anesthetic in the epidural space. Failure rate at the first attempt, puncture frequency, complications, and durations of block were recorded. Results The failure rate at the first attempt of caudal block were 16.7% in the conventional method group and 3.3% in the new method group (p<0.05). The mean time required (standard deviation) to perform needle insertion in the conventional method group was 2.6±0.5 minutes and in new method group 1.6±0.5 minutes (p<0.05). There were three cases aspirating the needle to find blood and one case to find cerebrospinal fluid in the conventional method group. The majority level which the local anesthetic reached are L1 by ultrasound imaging, 86.7% in the conventional method group and 83.3% in the new method group. Conclusion The study found that using the new method, the chance of performing a successful caudal injection can be increased, the time and the risk can be minimized compared to conventional technique. It is a safe and effective method.


Author(s):  
Tuna Balkan ◽  
Mehmet Emin Ari

Abstract An inverted pendulum system has been designed and constructed as a physical model of inherently unstable mechanical systems. The vertical upright position of a pendulum is controlled by changing the horizontal position of a cart to which the pendulum is hinged. The stability of the system has been investigated when a fuzzy controller is used to produce the control signal, while making a single measurement. It has been shown that by using simple fuzzy rules to allow real time computation with a single angular position measurement, the system can not be made absolutely stable. However, the stability and performance of the system have been considerably improved by shrinking the membership functions of angular position, computed angular velocity and control signal when inverted pendulum is very close to the vertical upright position.


Author(s):  
A Zarehshi ◽  
AA Gharehaghaji ◽  
AA Asgharian Jeddi

Recent developments in nanocomposites that are reinforced with polymeric fibers have heightened the need for a material in fast-moving parts of machines. The research to date has focused on tensile properties of nanocomposites reinforced with polymeric nanofibers, which were produced by the conventional methods. In this work, nanocomposites were fabricated by a novel approach that comprises epoxy resin, epoxy hardener, and PAN nanofibers in which the nanofibrous layer was placed in resin as spun during the electrospinning. Then, a nanocomposite with the same materials was made using the conventional method of layering. There were enhancements in elongation at break, fracture toughness, and stress at break of nanocomposites fabricated by in situ method in comparison with the nanocomposites fabricated using the conventional method of layering.


2007 ◽  
Vol 364-366 ◽  
pp. 920-924
Author(s):  
Feng Zhou Fang ◽  
Yu Chan Liu ◽  
Qing Xiang Pei ◽  
Xiao Tang Hu

A new method on examining the micro cracks of monocrystalline silicon during nano indentation is proposed. It is established based on a study of the increasing rate of absorbed energy in nano indentation. This method provides a simple approach in understanding whether cracks on the silicon surfaces occur, while it is tedious in conventional method.


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