Impulsive Energy Research Articles

ГЕНЕЗИС ЦІЛЕЙ І ЗАВДАНЬ ВИБУХОВОГО ШТАМПУВАННЯ (ДО 70-РІЧЧЯ ОДНІЄЇ З НАУКОВИХ ШКІЛ ХАІ)

The paper is devoted to development of one of the scientific schools Kharkiv Aviation Institute (Now National Aerospace University named after M. E. Zhukovsky “KhAI”). This school was born after World War II quite hard after period of National economy restoration and now it continues to develop during last 70 years. The article deals with the origins and genesis of objectives and tasks formulated for think tank and followers during dozens of years. Influence of the world geopolitics on development of mentioned scientific school and reached results is shown. From relatively primitive goals and tasks formulated by R. V. Pikhtovnikov in 1949 up to complicated problems of controlling of impulse energy flows to get high-precision large-dimensional sheet articles. From development of simple manufacturing process conducted in field conditions up to creation of up-to-date manufacturing complexes with correspondent buildings, equipment and technological jigs.Paper draws attention that successful development of scientific school and international expansion of labor market were stipulated by governmental support, both financial and organization ones. Paper shows results of technological systems development. Defefinite analogy with development of biological systems can be observed, i.e. evolution from the simplest to more complicated under influence of external factors.One has to note that paper deals with development of only one direction of scientific school, i.e. sheet articles forming. Research and development of such two other directions as impulse forming by impact of solid and impulse volumetric forming are waiting for their researchers. Authors of the paper tried to escape of conventional approaches of scientific schools description and concentrated on studying of objectives and tasks occurred in frames of considered scientific school. Therefore, the paper doesn’t mention many names of scientific advisors of different directions, titles of exact studies and topics, which involve crucial contribution in achievements of mentioned scientific school.

Evaluating significance of relation between a material electroerosion resistance and electroerosive machining pulse energy

The paper presents results of research into dependence of electroerosion resistance on the energy of discharge impulses during electroerosive machining. A new criterion is proposed for evaluation of electroerosion resistance of materials. A direct dependence has been determined experimentally between the electroerosion resistance and the energy of discharge impulses. This relation is weak and close to linear. A mathematical model has been developed for this dependence. Scope of application is defined for the research results.

Quantification of forearm muscle activation by ultrasound imaging and high-density electromyography

Assessment of skeletal muscle function is an active research area in rehabilitation and sports medicine. An effective assessment methodology can be used to evaluate muscle recovery or response to treatments or interventions, and for early diagnosis of skeletal muscle diseases when combined with corresponding biomarkers. The main objective of this study is to develop an engineering technique for detecting muscle activation by combined ultrasound imaging and high-density electromyography (HDEMG). An ultrasound speckle tracking algorithm was employed to measure the impulsive kinetic energy released by muscle contraction while the processed HDEMG depicted the spatial-temporal electrical response of the activated muscle. The location and time course of the muscle activation can then be quantified by detecting the precise onset of the mechanical and electrical signals from ultrasound imaging and HDEMG, respectively. To demonstrate the conceptual feasibility, experiments were performed, with synchronized dual-probe ultrasound imaging and HDEMG recorded, on the forearm of one human participant without an injury or disability. To test detections of different activation patterns, single electrical pulses were sent to the flexor carpi radialis (FCR), flexor digitorum superficialis (FDS) and the median nerve, respectively, to intentionally create cases where FCR and FDS can contract individually or simultaneously.

Kink Oscillations of Coronal Loops

Kink oscillations of coronal loops, i.e., standing kink waves, is one of the most studied dynamic phenomena in the solar corona. The oscillations are excited by impulsive energy releases, such as low coronal eruptions. Typical periods of the oscillations are from a few to several minutes, and are found to increase linearly with the increase in the major radius of the oscillating loops. It clearly demonstrates that kink oscillations are natural modes of the loops, and can be described as standing fast magnetoacoustic waves with the wavelength determined by the length of the loop. Kink oscillations are observed in two different regimes. In the rapidly decaying regime, the apparent displacement amplitude reaches several minor radii of the loop. The damping time which is about several oscillation periods decreases with the increase in the oscillation amplitude, suggesting a nonlinear nature of the damping. In the decayless regime, the amplitudes are smaller than a minor radius, and the driver is still debated. The review summarises major findings obtained during the last decade, and covers both observational and theoretical results. Observational results include creation and analysis of comprehensive catalogues of the oscillation events, and detection of kink oscillations with imaging and spectral instruments in the EUV and microwave bands. Theoretical results include various approaches to modelling in terms of the magnetohydrodynamic wave theory. Properties of kink oscillations are found to depend on parameters of the oscillating loop, such as the magnetic twist, stratification, steady flows, temperature variations and so on, which make kink oscillations a natural probe of these parameters by the method of magnetohydrodynamic seismology.

Low-energy high-frequency Ho-YAG lithotripsy: is RIRS going forward? A case-control study.

Retrograde Intra-Renal Surgery (RIRS) plays a primary role in renal stone treatment context. Energy, frequency and width of laser impulse can be modulated by surgeons to achieve better outcomes. In our study, patients with single renal stone sized 10-20mm were retrospectively divided into two groups. Patients of Group 1 underwent RIRS with Low-Energy (LE) High-Frequency (HF) settings using Lumenis® 120-W high-power Ho:YAG laser. Patients of Group 2 (control) underwent RIRS using "standard" settings by means of Sphinx® Jr 30W Ho:YAG system. Follow-up was conducted with a CT scan at 3months after RIRS in both groups. Procedure success was defined as stone-free or presence of ≤ 4mm fragments (Clinical Insignificant Residual Fragments-CIRF). A total number of 199 patients were included: 86 LE/HF RIRS (Group 1) vs 113 "conventional" RIRS (Group 2). Mean operative time was 56.6 (± 19.4) min in Group 1 vs 65.2 (± 25.2) min in Group 2 (p = 0.01). Mean hospitalization time was 2.5 ± 1.7days for Group 1 vs 2.9 ± 3.2days for Group 2 (p = 0.2). Peri-operative complications were counted: eight in Group 1 and 11 in Group 2 (p > 0.05). At 3-month control, stone-free rate was 69% (59/86 patients) in Group 1 vs 65% (73/113 patients) in Group 2 (p = 0.6). Success rate was 93% (80/86) in Group 1 in comparison to 82% (93/113) in Group 2 (p = 0.03). In conclusion, LE/HF RIRS seems to be a feasible and effective technique with a reduction of operative time and optimal results in terms of "stone-free" and "success" rates. Further studies are needed to ensure the validity of our results and to give evidence-based statements.

Prevention of IOL Laser Damage after YAG Laser Destruction in Children with Secondary Cataract

Background. In recent years there is a tendency to more often admission in our institution children with multiple IOL damage caused by laser treatment of secondary cataract operated at local hospitals.Purpose. To analyze the causes of laser damage to IOL in children underwent YAG laser destruction of secondary cataract and find best ways to prevent them.Patients and methods. We analyzed the frequency of acrylic IOL damage after YAG-laser destruction in 593 children with congenital, posttraumatic and postuveal cataract at age from 6 months to 17 years (one third of patients were less than 3 years old). All laser operations were performed on identical YAG-laser, by the same protocol and by one surgeon.Results. We confirmed that main reliable prevention factor of damage to IOL in children is the precise focus of laser beam. In past 10 years in our institution, we managed to decrease frequency of laser damage to IOL in children with secondary cataract in 4.5 times due to performing operations under general anesthesia (43.8 % in 2007–2008, 65.8 % in 2018). Thus, decreasing frequency from 5.9 % to 1.3 % in the same age group of patients.Conclusion. To achieve the effective prevention of laser damage to IOL in cases of YAG laser destruction of secondary cataract it is essential to use general anesthesia in following conditions: children 5 or below age, non-contact children of older age, children with nystagmus, CNS pathology, psychomotor development delay. It is unacceptable to perform this operations without general anesthesia in children that can’t fix the gaze. Furthermore it is important to use contact lenses to fix the eyes of a child, select the individual less invasive method and technique of laser operation, utilize single short impulses with minimal effective energy, thoroughly follow standard safe energy modes (impulse energy shouldn’t be more than 2.4 mJ, impulse number should be not more than 100).

Compound fault diagnosis of rolling bearings based on improved tunable Q-factor wavelet transform

In order to solve the difficulty of compound fault diagnosis of rolling bearings, a novel rolling bearings fault diagnosis method based on improved tunable Q-factor wavelet transform (TQWT) is proposed in this paper. Firstly, a new evaluation index of signal decomposition called KR is defined by summing kurtosis and root mean square (RMS) with weight. KR is the compromise between impulse factor and energy factor, which can better represent the fault characteristics of sub-bands obtained by TQWT. Secondly, the KR is used to improve the TQWT. The improved TQWT can adaptively determine the parameters Q-factor and decomposition level. Thirdly, the bearing vibration signal is decomposed by the improved TQWT and the sub-bands are sorted descending according to the KR. Finally, the Hilbert envelope analysis is carried out and the fault types are determined by comparing the fault characteristic frequencies obtained from the Hilbert envelopes to the fault characteristic frequencies calculated by formula. The proposed fault diagnosis method is fully evaluated by simulation and experiments. The results demonstrate that the KR takes advantage of kurtosis and RMS and can be better used to optimize the parameter of TQWT. And the compound fault features of rolling bearings can be accurately separated into different sub-bands by the improved TQWT, which is helpful to improve the accuracy of compound fault diagnosis of rolling bearings.

Noise Waveforms within Seabed Vibrations and Their Associated Evanescent Sound Fields

While the effects of sound pressures in water have been studied extensively, very much less work has been done on seabed vibrations. Our previous work used finite element modeling to interpret the results of field trials, studying propagation through graded seabeds as excited by impulsive energy applied to a point. A new simulation has successfully replicated further features of the original observations, and more field work has addressed other questions. We have concentrated on the water-particle motion near the seabed, as this is well known to be critical for benthic species. The evanescent pressure sound fields set up as the impulsive vibration energy passes are expected to be important for the local species, such as crabs and flatfish. By comparison with effects occurring away from boundaries, these seismic interface waves create vigorous water-particle motion but proportionately less sound pressure. This comparative increase ratio exceeds 12 for unconsolidated sediment areas, as typically used for piling operations.

Comparative analysis of electromechanical processes in induction-dynamic converter with mobile inductor and two disks

General description of the research topic. The article presents a comprehensive study of traditional induction-dynamic mechanisms (with one disk and a fixed coil) and multi-core induction-dynamic mechanisms (linear pulse induction converters) with a movable coil and two disks. Actuality of the topic. Such induction-dynamic mechanisms are widely used in various fields, in particular, in electrical apparatus industry, where speed is one of the most important characteristics. The purpose of the article is a comparative analysis and refinement of the characteristics of the traditional induction-dynamic system with one disk and a fixed coil and multi-core one with a movable coil and two disks. Research method, scientific novelty. The calculations are based on the solution of the equations of the electromagnetic field and the equations for the electric circuit of the coil. Practical significance and main conclusions. During the calculations, the values of electromagnetic force and force impulse acting on the moving disk, energy losses in the system and electromagnetic energy of the system are determined. The results of the study are presented in the form of graphs, namely, the coil current and total magnetic energy for a traditional induction-dynamic mechanism with one disk and for multi-core one with two disks, Joule losses in a fixed coil and disk (in a traditional system) and in a moving coil and two disks (in a multi-core system), force impulse and electromagnetic force of a moving coil (in a multi-core system) and a moving disk (in a traditional and a multi-core system) total impulse of the moving parts of the induction-dynamic mechanism with a multi-core system, as well as the electromagnetic force and the total force acting on the moving parts of the induction-dynamic mechanism with a multi-core system. It is shown that the induction-dynamic mechanism with two disks is less effective in terms of electromagnetic force, impulse and electromagnetic energy than the induction-dynamic mechanism of the traditional layout.

Integrated retrograde and antegrade contact electro-impulse lithotripsy in the treatment of kidneys and ureteropelvic junction stones

Introduction. Nowadays, the tactics of removing stones from the kidneys and the ureteropelvic junction are widely covered and described in detail in modern guidelines. Determination of one or another treatment way depends on stone specific features and patient`s constitutional peculiarities. However, usage of percutaneous or retrograde access only does not always allow achieving a good result. In sophisticated cases, such as a large-size branchy renal stone, a “penetrated” stone in the ureter’s upper third, or some patient`s anatomic peculiarities, search for new ways to remove such stones with integrating accesses. Purpose of the study. To evaluate the removal efficiency of kidney stones and ureteropelvic junction by a combination of retrograde and percutaneous lithotripsy using electrical impulse energy. Materials and methods. In 2014-2019 in Siberian State Medical University Clinics (Tomsk, Russia), the integrated retrograde and percutaneous lithotripsy was applied in 26 cases to patients that had differently positioned kidneys’ and ureteropelvic junction stones. The treatment was based on the usage of the electro-impulse lithotriptor Urolith-105M (Lithotech Medical, Israel, MedLine LLP, Russia). In some cases, the laser lithotriptor Calculase II (Karl Storz, Germany) was also engaged. Result. The patients were aged from 25 to 76 (women - 69.2%). The calculus average size was 19.5 mm (varying from 5 to 51 mm). The calculus average density was 1229 HU (from 510 to 1720 HU). The operation average duration was 131 minutes (from 40 to 280 minutes). The incidence of complications was 3.84%. The complete calculus destruction occurred in 92.3% of cases. The overall response rate in re-operations reached up 100%. Conclusion. Integration of antegrade and retrograde accesses with use of the electro-impulse energy in removing complex stones from ureteropelvic junctions and kidneys proved to be an efficient method of treatment and demonstrated great results. Furthermore, this option of the single-step access to the stones is the only one possible in some cases when the extracorporeal lithotripsy is contraindicated, application of upfront surgery is quite risky, or endoscopic methods as an antegrade/retrograde mono-access are not effective .

Wave redirection, localization, and non-reciprocity in a dissipative nonlinear lattice by macroscopic Landau–Zener tunneling: Theoretical results

We consider an asymmetric dissipative network of two semi-infinite nonlinear lattices with weak linear inter-lattice coupling and study its capacity for passive wave redirection and non-reciprocity. Each lattice is composed of linearly grounded oscillators with essentially nonlinear (i.e., non-linearizable) next-neighbor intra-lattice coupling, and it supports breather propagation. Irreversible breather redirection between lattices is governed by a macroscopic analog of the quantum Landau–Zener tunneling (LZT) effect, whereby impulsive energy initially induced to the “excited lattice” is passively and irreversibly redirected to the “absorbing lattice.” Moreover, this wave redirection is realized only in a specific range of impulse intensity (energy), otherwise motion localization occurs. In this work, we show that LZT breather redirection in the dissipative network occurs only when the normalized linear inter-coupling stiffness is larger than the viscous damping ratio of the individual lattice oscillators, with breather arrest and localization occurring otherwise. Then, through a reduced-order model, we provide guidance for selecting the system parameters of the lattice network for robust breather redirection despite the presence of dissipation. To this end, we study the acoustic non-reciprocity and formulate a quantitative measure for studying it based on measured time-series responses at the four free boundaries of the finite network. Then, we show the dependence of non-reciprocity in this system on the intensity (energy) of the applied impulse. These results pave the way for conceiving practical nonlinear lattice networks with inherent capacities for passive wave redirection and acoustic non-reciprocity that are tunable (self-adaptive) to the applied impulsive excitations.

Time-varying output formation tracking of heterogeneous linear multi-agent systems with dynamical controllers

This paper is concerned with the problem of time-varying output formation tracking of heterogeneous linear multi-agent systems on a directed communication topology that the leaders do not communicate with each other. Specifically, with injecting impulses to the states of the controllers, a dynamical control protocol is proposed, which not only reduces communication consumption, but also avoids the damage of the impulsive energy to the devices at impulsive instants. Besides, the protocol is designed using the measured output of the agents, which is more practical than those designed using the states of the agents. Then, some sufficient conditions with regard to the gain matrices and the coupling parameter are derived to guarantee that the states of the followers achieve time-varying output formation and track the convex combination of the states of the leaders as well. Finally, a numerical example is shown to validate the effectiveness of the theoretical result.

Simulation of impulsively induced viscoelastic jets using the Oldroyd-B model

Abstract

Hypothesis: Bacteria benefiting from electromagnetic field in peripheral neuropathy

ABSTRACT Recent research has already been shown widespread locations of bacteria in various tissues and organs of a healthy host organism. These bacteria (hereinafter referred to as persistent microbiota, PM) cause neither noticeable destruction nor toxins production – no immune response can be noticed either. The role of the PM is unknown. The host nervous system is not an exception and can also be inhabited by the PM. We found that various bacteria were capable of benefiting from the electromagnetic field (EMF). The main advantage of these bacteria, apparently, lies in the increasing supply of ionic forms of compounds into the cells. Since microorganisms use the energy of electrical impulses, their possible colonization of the host’s nerve circuit will weaken the nerve signals. The presented hypothesis aims to draw attention to the following points: i) microbial colonization of the host nervous system will lead to the weakening of nerve signals, ii) the sensitivity of bacteria to EMF permits to affect on their activity with electromagnetic treatment.

200 Years of Trafalgar: From Jubilation to Commemoration

The author of this article attempts to trace the evolution of the British memory concerning the Battle of Trafalgar, which predetermined the long-term dominance of Britain on the seas. Almost immediately after receiving the first news of Trafalgar and the death of H. Nelson, large-scale ceremonies began which were associated with a grand victory on the national scale. By the beginning of the twentieth century, the era of the “living memory” of Trafalgar was over. At the same time, radical changes in the balance of geopolitical forces made the British think again and again about Trafalgar. Even though the First and Second World Wars pushed the images of glorious victories at sea in the distant era of the Napoleonic wars into the background in the minds of the British, during the 150th anniversary of Trafalgar, the British military and state elite tried to revive the glorious images of the distant past, using “historical resources” to maintain the national spirit. The dynamics in the awareness of the British elite and the public of the importance of the anniversary was remarkable as it evolved from semi-indifference to events of the widest scope. Fifty years later, London made another attempt to use the anniversary of Trafalgar to raise patriotic sentiments among the British youth, as well as strengthen the military-strategic partnership with its allies. At the same time, analysts noted the progressive loss of the fundamental moments for the national identity of the British. The author concludes that the perception of the image of Trafalgar by the British has passed a difficult path over 200 years, which demonstrated a variant of the development of “living memory”, which, despite all attempts to preserve the energy and direction of the original impulse, is being inevitably replaced by what is now commonly called commemoration.

ИССЛЕДОВАНИЯ ПЕРЕДАЧИ СИЛОВЫХ ИМПУЛЬСОВ ЧЕРЕЗ РЕЗЬБОВЫЕ СОЕДИНЕНИЯ БУРИЛЬНОЙ КОЛОННЫ ПРИ ВРАЩАТЕЛЬНО-УДАРНОМ БУРЕНИИ ПИЛОТНЫХ СКВАЖИН ДЛЯ БЕСТРАНШЕЙНОЙ ПРОКЛАДКИ ТРУБОПРОВОДОВ

Актуальность. Пилотные скважины при горизонтально-направленном бурении можно отнести к скважинам малого диаметра, которые находят широкое применение в горном деле, в частности, для детальной разведки и подземной разработки руд цветных металлов, для дегазации горных выработок угольных шахт, а также во многих других отраслях промышленности, где необходимо по технологическим или техническим условиям ограничивать диаметр скважины. Для эффективного бурения таких скважин в перемежаемых по твердости горных породах буровые установки оснащаются ударными механизмами, формирующими в бурильной колонне ударные (силовые) импульсы в виде волн упругой деформации, воздействующие через бурильную колонну на разрушаемую горную породу.При этом неизбежно рассеивание энергии импульсов в резьбовых соединениях. Если соединения бурильных труб предназначены только для вращательного бурения, то потери энергии силовых импульсов в них могут быть недопустимо большими, а работоспособность и прочность существенно снижены. Хотя резьбовые соединения принято считать неподвижными, в действительности при одновременном нагружении их крутящим моментом, усилием подачи на забой бурового инструмента и силовыми импульсами неизбежно возникают малые проскальзывания по контактным поверхностям элементов соединений бурильных труб. На этих относительных перемещениях совершают работу силы трения, вызывая энергетические потери, количественно оценить которые можно экспериментальным путем.Научное обоснование и разработка рекомендаций по проектированию и созданию новых конструкций резьбовых соединений бурильных колонн для повышения эффективности способа вращательно-ударного бурения скважин является актуальной научно-технической задачей. Цель: выполнить анализ динамических процессов в резьбовых соединениях бурильной колонны при передаче силовых импульсов от ударного узла к породоразрушающему инструменту;построить гистерезисные диаграммы, позволяющие на основе выполненных экспериментов оценить энергетические потери, связанные с работой сил неупругого сопротивления в местах контакта сопряженных деталей резьбовых соединений во время распространения через них силовых импульсов;показать на примерах бесполезность попыток добиться эффективной передачи ударных импульсов через соединения труб, применяемых при вращательном способе бурения, и обосновать рекомендации по разработке принципиально новых ниппельных соединений труб, предлагаемых Национальным исследовательским Томским политехническим университетом для бурения пилотных скважин, ранее успешно прошедших производственные испытания на рудниках цветной металлургии в Кыргыстане и Казахстане с непосредственным участием авторов. Объектом исследования являются бурильные колонны с муфтовыми и ниппельными соединениями, которые применяются при вращательно-ударном способе бурения скважин, а также резьбовые соединения труб для пилотных скважин горизонтально-направленного бурения. Методика: обзор источников научной литературы по вопросам передачи ударных импульсов по бурильной колонне; обоснование возможности эффективногоиспользования вращательно-ударного способа бурения для прокладки коммуникаций бестраншейным методом, а также определение величины потерь энергии в резьбовых соединениях труб на основе моделирования нагружения на лабораторном стенде. Результаты. На основе экспериментальной работы и компьютерного моделированияустановлены взаимосвязи параметров резьбовых соединений и эффективности передачи ударных импульсов по бурильной колонне; выявлено, что обеспечение минимально возможного значения жесткости соединительного элемента при наибольшей контактной жесткости сопряженных витков соединения приводит к повышению коэффициента передачи амплитуды силы и энергии импульсов. Применяемые в настоящее время соединения бурильных труб для горизонтально-направленного бурения скважин не пригодны для вращательно-ударного способа бурения из-за отражений волн деформации от участков резьбовых соединений бурильных труб без соединительных элементов (муфт или специальных ниппелей закрытого типа).

Gender Differences in Psychological Symptoms and Psychotherapeutic Processes in Japanese Children.

Gender differences have been documented in the prevalence of psychological symptoms. Tic disorders and autism spectrum disorder (ASD) are more common in male clinical samples, while selective mutism and trichotillomania are more common in female clinical samples. In a review of 84 published case studies of Japanese children, this study explored gender differences in the prevalence of four categories of symptoms and expressions made in therapy for tics, selective mutism, autism spectrum disorder (ASD), and trichotillomania. Case studies were evaluated using both qualitative coding and statistical analysis. The findings were mostly consistent with epidemiological surveys and empirical research on adults. The gender differences in symptom prevalence and their expression could be summarized as differences in more direct aggression for boys versus indirect aggression for girls. The objective and progress in the therapy were to control impulsive energy for boys and to express energy for girls.

Oscillation and Evolution of Coronal Loops in a Dynamical Solar Corona

Observations have revealed two regimes of kink oscillations of coronal loops. Large amplitude oscillations excited by impulsive energy releases such as coronal mass ejections are characterised by their strong damping by resonant absorption. Lower amplitude oscillations may also be excited and sustained by the ubiquitous motions present in the corona and so are characterised as being decayless. We perform numerical simulations to study the oscillation and evolution of coronal loops in a dynamical environment. We investigate the observational signatures of kink oscillations and the Kelvin-Helmholtz instability in terms of high-resolution seismological and spatial data analysis techniques. We find that low amplitude kink oscillations are capable of generating significant changes in the loop profile which can affect estimates of the transverse loop inhomogeneity based on seismological and forward modelling methods. The disparity between methods may be indicative of nonlinear evolution of coronal loops. The influence on forward modelling estimates could also account for previous observational evidence favouring loops having wider inhomogeneous layers.

Solar Flare–CME Coupling throughout Two Acceleration Phases of a Fast CME

Abstract Solar flares and coronal mass ejections (CMEs) are closely coupled through magnetic reconnection. CMEs are usually accelerated impulsively within the low solar corona, synchronized with the impulsive flare energy release. We investigate the dynamic evolution of a fast CME and its associated X2.8 flare occurring on 2013 May 13. The CME experiences two distinct phases of enhanced acceleration, an impulsive one with a peak value of ∼5 km s−2, followed by an extended phase with accelerations up to 0.7 km s−2. The two-phase CME dynamics is associated with a two-episode flare energy release. While the first episode is consistent with the “standard” eruption of a magnetic flux rope, the second episode of flare energy release is initiated by the reconnection of a large-scale loop in the aftermath of the eruption and produces stronger nonthermal emission up to γ-rays. In addition, this long-duration flare reveals clear signs of ongoing magnetic reconnection during the decay phase, evidenced by extended hard X-ray bursts with energies up to 100–300 keV and intermittent downflows of reconnected loops for >4 hr. The observations reveal that the two-step flare reconnection substantially contributes to the two-phase CME acceleration, and the impulsive CME acceleration precedes the most intense flare energy release. The implications of this non-standard flare/CME observation are discussed.

A Novel Condition Indicator for Bearing Fault Detection Within Helicopter Transmission

Helicopter usage and monitoring system (HUMS) is one of the critical systems for helicopter’s safety and reliability. Whilst HUMS has proven to be effective in detecting gears’ defects, bearing failures are not adequately detected using current monitoring indicators. Detection of bearing faults in helicopter gearboxes is made challenging by the presence of the complicated signal transmission path attenuating the monitored signal to the receiving sensor. To ensure safe operation of helicopters, this research proposes a novel condition indicator to detect bearing faults in helicopter gearboxes. For this purpose, vibration measurements captured from a CS-29 category ‘A’ helicopters test rig were utilized for detecting a bearing defect that has occurred in the epicyclic module of the main gearbox. Signals of rolling element bearings under various fault conditions were collected, and an adaptive filter algorithm was utilized to separate the random component of the signal. The resultant signatures were then further processed using wavelet analysis to extract the bearing signal of interest. Results showed that this new indicator successfully detect bearing faults. Besides, the impulse energy indicator responds consistently to the fault severity compared to the traditional indicators such as RMS and kurtosis. A technique to extract frequency band corresponding to the bearing fault impulses has been developed and tested. The technique employs the adaptive filter signal separation, wavelet packet decomposition and the combination of RMS and kurtosis to select the optimum filter band.