Standstill State Research Articles

Discovery of a new IW And-type dwarf nova with both tilted disc and tidal instability

ABSTRACT IW And-type dwarf novae are anomalous Z Cam stars featured with outbursts happening during standstill states, which are not expected in the standard disc instability model. The physical mechanisms for these variations remain unclear. In this study, we report the discovery of a new candidate IW And-type dwarf nova J0652+2436, identified with its frequent outbursts from the slowly rising standstill states. Luckily, the Transiting Exoplanet Survey Satellite observations during a long standstill state and the earlier K2 observations give a chance to find the orbital and negative superhump period in the light curve of J0652+2436, allowing the measurement of its mass ratio of 0.366. This mass ratio is marginally possible for the tidal instability to set in according to previous smoothed particle hydrodynamics simulations. Thus, we propose that the outbursts in J0652+2436 are likely to be caused by the growing accretion disc during standstills, in favour of the previous hypothesis of the mechanisms lying in all IW And stars. We conclude that J0652+2436 might be the first IW And star with both a precessing tilted disc and tidal instability, which will be an important laboratory for studying the accretion disc dynamics and help understand the IW And phenomenon.

Safe Distance Model for Control of Vehicle Emergency Collision Avoidance

The vehicle needs to be able to assist the driver in realizing the control strategy of emergency collision avoidance to ensure the safety of car drivers during driving. This article introduces the basic principles of vehicle emergency collision avoidance using time to collision (TTC) and Berkeley safety distance models. In addition, the Berkeley model was improved so that it could be adjusted for different driving styles. On the simulation platform, simulation experiments were carried out on the driving conditions of the front vehicle at a standstill state, at a constant speed and at a deceleration state. The performance of three collision avoidance strategies were analysed. The results showed that the extroverted driver had the fastest response speed, followed by the moderate driver and the introverted driver; no matter what the working condition, the increase in the driving speed of the driver could reduce the distance between the vehicle and the vehicle in front when the vehicle stopped due to braking, increasing the risk of rear-end collision; no matter what the working condition, the anti-collision strategy that adopted the improved Berkeley model could effectively adapt to different driving styles, keeping a stable distance from the front vehicle when stopping due to braking and the distance between the vehicles was larger than the other two collision avoidance strategies.

Methodology to Evaluate the Mechanical Stress in High-Speed Electric Machines With Buried Magnets

High-speed electric machines are gaining importance due to their high power density. The evaluation of the mechanical stress in the rotor is a crucial part of the design process for this type of machines. It is insufficient to evaluate just the static mechanical stress at maximum speed. The dynamic mechanical stress between the state of standstill and maximum speed needs to be considered as well to ensure the high fatigue strength of the rotor. One criterion that is commonly used to analyze the dynamic load in a material is the Smith diagram. In this work, a new methodology is introduced to consider both, the dynamic and the static mechanical stress, in the rotor of a high-speed electric machine. First, the von Mises stress criterion is used to examine the static mechanical stress in the rotor core. Second, the Smith diagram is used to evaluate the dynamic mechanical stress and the high fatigue resistant of the rotor. The methodology is, then, applied to a high-speed electric machine with two different types of buried magnets: 1) a rotor with buried magnets in v-shape and 2) a rotor with a buried bar magnet. Both rotors are analyzed concerning their state of stress. It can be seen that high dynamic stress occurs at the bridges in the rotor. The stress alternates with an amplitude up to σ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">alt </sub> = 290 MPa. The designs are though limited due to the high static stress at the bridges of the magnet slot.

Threats and Opportunities of the COVID 19 on Tourism Industry in Sri Lanka and South Asian Region

Covid 19 Global pandemic has now brought the entire socio-economic structures in to a standstill state all over the world. It has already challenged the global operations of several business sectors. Time has come to rethink how to recover and regain of the economy, employment and business functions with a fresh beginning in most of the worsened economic sectors. South Asia (Bangladesh, Bhutan, India, Pakistan, Nepal, Sri Lanka; Afghanistan and the Maldives) with a population of 1.8 billion has been severely affected by the COVID-19 pandemic due to poor public health infrastructure, pervasive informality and poor coverage of social protection. The key sectors such as MSMEs, tourism and labour-intensive exports such as readymade garments have been most adversely impacted, leading to loss of jobs for the millions of people in the sub-region. The economic growth has come to a grinding halt and the threat of rising incidence of poverty, hunger and inequality is real. This sudden fall in tourism industry have created severe economic and social consequences within and beyond tourism in the region. Sri Lanka is a country with open economy, has hit badly under this circumstances, in particularly the Sri Lankan export market. Sri Lankan Rupee is depreciating and U.S Dollar has increased to Rs.197/= by January 2021. Total export of Sri Lanka in 2019 was $16.14Bn which comprised $11.94Bn from Merchandise exports and $4.2Bn from service sector. The services sector revenue generation was mainly from the tourism industry which amounts to $3.6Bn during 2019. However this was 18% drop compares to previous year which was $4.2Bn in 2018, following the Easter Sunday attack in April 2019. As a result of Covid – 19 global pandemic outbreaks, many countries imposed travel restrictions and locked down no of cities/countries. Sri Lankan government imposed Island wide curfew on 20^th March 2020 resulting tourism industry dropped to the bottom while crippling the Sri Lankan economy. For Sri Lanka, tourism sector’s contribution towards countries development is been quite considerable. This paper discuss the present situation, how to recapture the tourism market and to create new opportunities for future growth in this foreign currency earning very important sector in Sri Lanka as well as in South Asian Region.

“Remaining” as the Natural Expression of the Ontological Monism in Proclus and Pseudodionysius the Areopagite

This study is a comparative investigation of Proclus’ and Pseudo-Dionysius the Areopagite’s positions about “remaining” as demonstrative of the ontological monism. Focusing the attention, first of all, to the Neoplatonist philosopher, who represents polytheism, it comes that “remaining” indicates the state of standstill and unchangeability of those beings which are able to function as productive principles. Thus, a transcendental and a productive plane are identified, a parameter which combines the apophatic with the affirmative approaches. The theory about “unparticipated-participated-participating” brings to the light a middle phase between “remaining” and “procession”, in order the relation “one-multitude” to develop. In Pseudo-Dionysius the Areopagite, “remaining” appears in two planes: a) the transcendent One, which does not take part in the production process, b) the One which includes all the beings in the form of archetypical reasons. Note that this is not an eternal co-existence or an ontological identification of the beings with the One’s substance or a transition from the first One to the second, as Proclus suggests. Pseudo-Dionysius just describes the providential function of the One, which is manifested owing to its goodness. In conclusion, the main difference between the two thinkers is how they conceive the notion of “metaphysical multitude”: in Proclus, it indicates a hierarchy of beings, while, in Pseudo-Dionysius, it expresses the inner richness of the unity. In both the worldviews though, the ontological prospect which is formed is actually an optimistic one.

RANCANG BANGUN MOBIL AERO ANTI GRAVITASI BERBASIS MIKROKONTROLLER DSPIC30F

&lt;p&gt;The car continues to develop the technology for the sake of convenience for the user to get a car. Currently the cars already provide many services, including : features - features, the fuelefficient, environmentally friendly, and safety while driving. But comfort when driving on the road is still not perceived as bottlenecks that often occur. Cars are often stuck in traffic will experience a diecasting machine, because the machine lights up constantly - constantly in a state of standstill. Researchers of this problem offers solutions in the field of transport. Researchers create Design of Aero Anti-Gravity Car Microcontroller-based dsPIC30F . It was inspired from a means of transportation that can resist the force of gravity, among others : airplanes, helicopters, jets and rockets. So that the principle of work on the Anti-Gravity Car s is the aerodynamic system of microcontroller-based dsPIC30F. &lt;br /&gt; &lt;br /&gt;Keywords : Aero Anti-grvitasi Car, DSPIC30F.Aerodynamic&lt;/p&gt;

Current Epidemiological Data on Asthma Management in South Korea from Qualitative Assessment of Asthma Management by Health Insurance Review and Assessment Service (HIRA).

Since 2015, the Health Insurance Review and Assessment Service (HIRA) has performed annual qualitative assessments of asthma management provided by all medical institutions that care for asthma patients in Korea. According to the third report of qualitative assessment of asthma management in 2017, the assessment appears to have contributed to improving the quality of asthma care provided by medical institutions, especially primary clinics. However, there is still a gap between the ideal goals of asthma management and actual health care policies/regulations in real clinical settings, which leads to the state of standstill with respect to the quality of asthma management despite considerable efforts such as the qualitative assessment of asthma management by national agencies such as the HIRA. At this point, a harmonized approach is needed to raise the level of asthma management among several components including medical policies, efforts of academic associations such as education and distribution of the guideline for management, and reliable financial support by the government.

Effect of Memantine on Motor Behavioral Phenomena in Rats of Different Ages

Alzheimer’s disease is a neurogenerative disease characterized by significant worsening of memory, disorders in the emotional sphere, and impairment of cognitive and motor functions. Agonists of NMDA receptors are used as potential therapeutic agents for correction of the above disorders, and memantine is one of such drugs. This agent decelerates the progressive development of neurodegenerative processes. It demonstrated a neuromodulatory action on motor behavioral phenomena in 2- and 13-month-old rats placed in nowel conditions of free behavior; estimation was performed before and after peroral introduction of 10 mg/kg memantine. Videorecording of the animals’ behavior with subsequent analysis of the records was used in the experiments. According to the obtained data, memantine decreased, in general, motor activity of the rats, increased the duration of episodes of their quiet standstill state, and, simultaneously, somewhat increased the intensity of research phenomena. These results show that memantine weakens the state of fear and anxiety related to potential dangers in an unknown surrounding, promotes manifestations of the research reflex, and makes adaptation of the rats to novel conditions more rapid.

Hurricane-Induced Loads on Offshore Wind Turbines with Considerations for Nacelle Yaw and Blade Pitch Control

During extreme tropical storm systems such as hurricanes, offshore wind turbines are required to have adequate structural integrity in parked condition and with blades pitched to feather. Such turbine states are preferred in order to mitigate loads on the turbine blades; simultaneously, yaw control is required so as to track the changing wind direction in this configuration. During a hurricane, however, it is possible that a turbine's yaw control system might operate abnormally due to damage of the control and protection system or due to loss of the electric grid and/or insufficient backup power. In earlier studies, the authors have shown that feathered blades can lead to higher tower bending moments in the side-to-side (lateral) direction rather than in the fore-aft (longitudinal) direction. In the present study, we carry out an in-depth investigation of the effect of several alternative parked configurations on an offshore turbine's response using numerical simulations with coupled wind-wave fields during a hurricane. We use these output wind-wave fields obtained from the University of Miami Coupled Model (UMCM), a fully coupled atmosphere-wave-ocean model that is used to simulate the storm and associated environmental fields and is able to represent relevant physical processes at the air-sea interface. In this study, we evaluate: (1) the effect of different nacelle yaw angles relative to the wind direction (i.e., different amounts of yaw error or misalignment); (2) the effect of different blade pitch angles; (3) the effect of different turbine parking strategies—e.g., parked and at a standstill or in an idling state; and (4) load maxima at different blade azimuthal configurations while the turbine is in a standstill state. The effects of the different turbine parked configurations on turbine response are evaluated under only wind loads first; later, wave loads are included to reflect possible joint metocean conditions likely to be encountered during a hurricane.

Gendered innovations in orthopaedic science: Title IX education: book learnin' and bone mendin'.

Gendered innovations in orthopaedic science: Title IX education: book learnin' and bone mendin'.

Polyphosphazene membrane for desulfurization: Selecting poly[bis(trifluoroethoxy) phosphazene] for pervaporative removal of thiophene

Concerning the standstill state of pervaporation desulfurization, development of new pervaporation desulfurization membranes is vital. The polymer selection can be based on solubility parameter theory. Using group contribution method, the solubility parameter of poly[bis(trifluoroethoxy) phosphazene] (PTFEP) was calculated. The differences in solubility parameters between thiophene and polymers including PTFEP were calculated and investigated for their potential application as pervaporation desulfurization membranes. PTFEP had the most similar solubility parameter to thiophene among the polymers calculated in this work. The results indicated superior possibility for its application in pervaporation desulfurization. PTFEP was thus synthesized and characterized by DSC, GPC, XPS, 1H-NMR and 31P-NMR. The PTFEP composite membrane was fabricated and utilized in pervaporation removal of thiophene. A pretty high sulfur enrichment factor of 15.69 was obtained which confirmed the results suggested by the solubility parameter theory. Compared with literatures, we positively believe that an increase in solubility parameter differences causes a decrease in sulfur enrichment factor. Meanwhile, the swelling behavior and morphology of the membrane, the effect of feed temperature, and the effect of feed sulfur concentration were also investigated.

放射光動的トポグラフ法の開発と二次再結晶過程観察への応用

White X-ray topography by synchrotron radiation provides a powerful means for dynamic imaging and mapping of structural inhomogeneities in bulk materials. "Synchrotron radiation dynamic micro topography method" has been developed by a combination of a high performance furnace and a direct type X-ray TV camera to white synchrotron radiation for the best use of the highly bright and parallel beam of synchrotron radiation source at the Photon Factory in the National Laboratory for High Energy Physics. The method has been applied to dynamic observation of rapidly progressing phenomena at high-temperatures such as the migration of secondary recrystallization fronts in grain-oriented silicon steel.The migration of secondary recrystallization fronts is found not uniform in both time and location. Migrating fronts show a zigzag shape and move from protruding points preferentially. The migrating behavior shows the following three types : burst motion at a rate of 0.05 to 0.2 mm/s, gradual migration with 0.01 to 0.02 mm/s, and standstill state. The size of regions consumed by a front motion is constant and is as large as 0.2 to 1.0 mm in diameter. Dislocations are observed in the growing grains and subboundaries are formed by connection of migration fronts to surround retained areas.

A novel approach on a parameter self-tuning method in an ac servo system

This paper describes a newly developed parameter identification method for three-phase induction machines. The identification is performed in two steps corresponding to the two states of the machine, namely the initial standstill state and the normal operating state. In each step, on-line identification of parameters indispensable to description of the machine dynamics can be realized by observing the behaviour of the stator current and voltage. These parameters are stator winding self-inductance, transient inductance, rotor circuit time constant and stator winding resistance. At standstill state, they are identified from the stator voltage waveform, when a ramp current is supplied to the stator by a dc power amplifier. At the operating state these parameters are identified by solving a set of equations obtained from the phasor relationship between stator current and voltage. This identification technique is applied to a PWM drive system and can lead to parameter self-tuning in an ac servo control system.

On Several Problems Regarding the Development of Demographic Theory in China Since the Founding of the People's Republic

Policy theory over the last 30 years, as Comrade Tian sees it, can be divided into 3 developmental stages: 1) from 1949 to 1957 saw the rise of "population controlism" represented by the sociological school; 2) from the late 1950s into the early 1960s featured the "new Population Theory" represented by Ma Yinchu, and a "theory of human hands and power" formulated in the course of criticism and repudiation; and 3) after the 1960s population studies were at a state of standstill or only 1/2 active. While advocating birth control, Comrade Mao Zedong showed inadequacy in regard to demographic theory and in practice he lacked sufficient understanding of the gravity of New China's population problem. In reviewing the developmental history of demographic theory in new China, it would be very inappropriate not to analyze and evaluate realistically Mao Zedong's thinking on population but only criticize certain of his faults. The main manifestations in Comrade Tian Xueyuan's division of the stages of development of new China's population theory are: 1) the first stage is unable to reflect accurately the objective reality of a healthy development of China's population theory, 2) the third stage includes 2 entirely different developmental periods before and after the smashing of the "gang of four," and 3) Tian's stages did not convey the development and change in Comrade Mao Zedong's demographic thinking in the different stages and their influence on the development of China's population theory. Tian Xueyuan and Zedong differ in terms of content of the developmental stages of population theory, not in terms of the time of the stages.

A Novel Approach on Parameter Self-Tuning Method in AC Servo System

This paper describes a newly developed parameter identification method of induction machine. Identification procedure consists of two steps: one is at initial state of standstill and the other is at operating state. In each step, on-line identification of parameters indispensable to description of machine dynamics can be realized by observing behaviors of stator current and voltage. They are stator winding self-inductance, transient inductance, rotor circuit time constant and stator winding resistance. At standstill state, they are identified from stator voltage wave to ramp current. At operating state these parameters are also identified by solving a set of equations obtained from vectorial relation between stator current and voltage. This identification technique is applied to PWM drive system and can lead to parameter self-tuning in ac servo control system.