WAVE FORMATION AT THE SUPER-FINISHING DISCS CERAMIC

The phenomenon of wave formation on the super-finished surface of ceramic disks made of ceramic materials with different machinability is considered. The General nature of wave formation during superfinishing and other machining processes (grinding, runningin) due to the loss of stability of the technological system is shown. Reviewed the condition of wave generation, including higher cutting speeds, it is necessary to increase the performance of the super-finishing, and changes sizes of diamond bar height on the buckling and wave generation on the treated surface of the ceramic disk. The influence of the processing time and the interaction force of the bar and the workpiece on the frequency of self-excited vibrations and wave formation is revealed. It has been experimentally established that with a decrease in the workability of ceramics, the rate of increase in the waviness amplitude decreases. Recommendations for reducing the rate of increase in the height of undulation are given.

E-Line Powered Mechanical Tool Technologies Provide Efficient, Reduced Risk Solutions in Complex Intervention Operations

Latest developments in drilling and wellbore completion technologies lead to even more complex intervention conditions. Conventional techniques using slickline or coiled tubing are ill-suited for many of these conditions due to operational complexity, effectiveness, or efficiency. Powered mechanical intervention with e-line alleviates some of these limitations and opens lower risk intervention applications. This paper details two applications: a fishing operation that could not be performed with slickline or coiled tubing and a completion disk rupturing operation where the operator saved 1.5 days. Powered mechanical intervention is a combination of complementary technologies that enable "intelligently controlled intervention operations." Downhole tractors enable access into complex well trajectories. Surface-controlled, powered anchors coupled with a linear actuator can generate very high axial forces with precise and real-time downhole measurements of forces and displacement. Operating parameters can be monitored in real time to prevent damage to damaged completion components. Uncontrolled tool movement due to high differential pressures is prevented. Such precise control of downhole forces and movements enables complex intervention operations previously done with coiled tubing or a full workover. The first application example details a fishing operation. A retrievable plug along with its setting tool was stuck in the production tubing after prematurely setting. Multiple fishing attempts with heavy-duty slickline jars were unsuccessful. Coiled tubing was not deployed as its lack of force precision could have generated excessive downhole force and sheared the fish. An e-line-conveyed linear actuator tool was used to latch onto the fish with the help of an overshot and was released from the retrievable plugs by application of optimal, highly controlled, linear force to minimize damage. The second case involved rupturing a ceramic disk installed in completion. High differential pressure across the disk restricted the use of slickline which could have been damaged due to the high expected differential pressure. The alternative with coiled tubing milling requires a larger personnel and equipment footprint in addition to the associated HSE exposure and lack of efficiency. An innovative technique using the e-line linear actuator and a pointed chisel was devised and deployed. Real-time feedback from the tool sensors gave confirmation of the rupturing of various components of the ceramic disk, and the anchors eliminated any tool movement during pressure equalization. The operation was completed in 12 hours, resulting in time savings of almost 36 hours. An e-line intervention is a low risk, effective, and efficient solution while having an accurate depth and positioning, coupled with controlled downhole operations. With precise control of operating parameters, operations which were previously possible with coiled tubing or workover can be done on e-line more efficiently.

Optimization of Non-Uniform Deformation on Piezoelectric Circular Diaphragm Energy Harvester with a Ring-Shaped Ceramic Disk

Piezoelectric energy harvesting technology using the piezoelectric circular diaphragm (PCD) has drawn much attention because it has great application potential in replacing chemical batteries to power microelectronic devices. In this article, we have found a non-uniform strain distribution inside the PCD energy harvester. From the edge to the center of the ceramic disk, its output voltage first increases and then decreases. This uneven output voltage reduces the output power of the PCD energy harvester. Based on this phenomenon, we reduce the ceramic disk diameter and dig a hole in the center, analyzing the effect of removing the ceramic disk’s low output voltage part on the PCD energy harvester. The experimental results show that removing the ceramic disk’s low output voltage part can improve the output power, reduce the resonance frequency, and increase the optimal impedance of the PCD energy harvester. Under the conditions of 10 g proof mass, 9.8 m/s2 acceleration, the PCD energy harvester with a 19-mm diameter and a 6-mm hole can reach a maximum output power of 8.34 mW.

Degree of Conversion of Light Cured Resin Cements Polymerized under Two Thicknesses of Different Lithium Silicate Ceramics

Objective: To show the consequence of two thicknesses of ceramic on the polymerization of resin cement light cured when three different lithium silicate ceramics were used. Materials and Methods: 42 ceramic slices were prepared from three types of ceramics, Emax CAD, Celtra Duo CAD and Vita suprinity CAD (n=14). They were further divided into two subgroups according to thicknesses into sub group thickness 0.5mm and sub group thickness 1mm (n=7). Teflon moulds were fabricated with specific dimensions, where the ceramic disc was placed followed by light cured resin cement Bisco choice 2 veneer and a glass slab with finger pressure applied. Curing with Ascent® PX LED light cure unit for 20 seconds took place, where the tip placed over the ceramic sample directly. Cement film was then separated from the ceramic disk and subjected to analysis by Fourier Transform Infrared Spectroscope. Uncured cement samples were also subjected to analysis. Results: Celtra DUO CAD ceramic showed higher degree of polymerization that of Emax and Vita suprinity while the difference between Emax and Suprinity on the degree of polymerization was not significant. Also, ceramic thicknesses had a significant effect on the degree of polymerization of the resin cement. Conclusion: Thickness of ceramics up to 1mm affects the polymerization of resin cement significantly.

Влияние ультразвукового излучения на время всплытия микропузырьков воздуха

Представлены результаты экспериментального исследования влияния ультразвукового излучения, генерируемого дисковым пьезокерамическим элементом ЦТС-19, на время всплытия микропузырьков, выделяемых из пересыщенного воздухом водного раствора. Показано, что под действием ультразвука происходит объединение пузырьков в комплексы, что увеличивает скорость их всплытия. Зависимость времени всплытия от частоты излучения носит сложный характер, применение ультразвука с частотой 160 кГц может снизить время всплытия с 39,9 до 13,5 с. Результаты работы могут быть использованы для увеличения производительности установок очистки сточных вод методом напорной флотации. The paper presents the results of an experimental study of the effect of ultrasonic radiation generated by a piezoelectric ceramic disk on the ascent time of microbubbles released from an aqueous solution saturated with air. It was shown that being irradiated by ultrasound, the bubbles combine into complexes, which increases the rate of their ascent. Dependency of the ascent time on the frequency of ultrasonic radiation is of a complex nature; however, the use of ultrasound with a frequency of 160 kHz can reduce the ascent time from 39.9 to 13.5 s. The results can be used to increase the productivity of wastewater treatment plants by pressure flotation.