Multi Turn Research Articles

A Perspective of Multi‐Reflecting TOF MS

ABSTRACTTime‐of‐flight mass spectrometry (TOF MS) excels in rapid and high‐sensitivity analysis, making it a cornerstone of analytical chemistry. But as sample complexity explodes in omics studies, so does the need for higher resolving power to ensure accurate results. Traditional TOF instruments face a challenge: achieving high resolution often requires a very large instrument. To overcome this limitation, scientists developed alternative designs for TOF analyzers called multi‐pass TOF analyzers (MPT). These MPT analyzers come in two main configurations: multi‐turn (MTT) and multi‐reflecting (MRT). Drawing on the authors’ extensive experience, this review describes two decades of MPT advancements. It highlights the critical development of optimized analyzer designs, tracing the evolution towards mirror‐based MRT instruments, generally providing superior resolution and spatial acceptance compared to MTT. While the manuscript attempts to overview MTT advances, it primarily focuses on MRT technology. Additionally, the review explores the role of orthogonal accelerators and trap pulse converters, comparing their efficiency and the dynamic range limits imposed by space charge effects. By comparing various MRT configurations and commercially available instruments, the review sets out to inform and empower researchers so they can make informed decisions about MRT mass spectrometers.

Experimental investigation on microstructure, hardness and corrosion resistance of an electromagnetic welded titanium-stainless steel dissimilar materials

The electromagnetic welding (EMW), often known as magnetic pulse welding, is a solid-state welding technology that is used to join two different materials using high-velocity impact. In this study an attempt was made to join the Titanium(Ti)- Stainless Steel(SS 304) materials with the help of multi turn disc coil along with the field shaper. A comparative investigation was conducted on the joint’s microstructure, as well as its mechanical and corrosion properties. Inverted optical microscopy (OM) and x-ray diffraction (XRD) were used to do the microstructural characterization of the joint. The micro-Vickers hardness test was used to analyse the material’s mechanical properties. In addition, electrochemical experiments were run on the Ti-SS 304 EMW junction as well as the component materials to establish how resistant they were to corrosion. Using an electrochemical impedance analyzer, the levels of corrosion that were caused by the structures were measured while they were submerged in a solution of nitric acid at room temperature. The microstructural pictures revealed a wave-like pattern at the material’s interface, which is evidence of strong adhesion between the components. The micro vickers hardness of the joints was within the permitted range, as was the corrosion rate.

Comparative analysis of CLPHP working with binary mixtures in different concentrations

The advanced technologies in design and manufacturing of electronic components have resulted considerable heat flux through component miniaturization. For highly performing microelectronic devices production, thermal management has the priority. Other applications also like material science, fabrication technology, solar applications etc. which directly impact cost, reliability and performance. When it comes to overcome these problems efficient cooling approaches development and use will come into play. The best solution for this is Pulsating heat Pipe (PHP). A simple PHP is a two-phase heat transfer device consists of a tube with a suitable working fluid, along with an evaporator (heating)section, adiabatic section and a condenser (cooling)section. In the present work multi turn Closed Loop Pulsating Heat Pipe (CLPHP) is chosen with capillary dimensions. The experimentation is carried out with different working fluids viz. water, water-based mixtures (75%-25%) at different volumetric fill ratios 50%,60% and 75%. The heat inputs of20W, 40 W, 60 W, 80 W, 100 W applied. At various heat inputs for all the working fluids the variation of thermal resistance is plotted and observed that upon increasing heat input, thermal resistance of fluid decreases. Comparative study is also presented for same experimental setup when the binary mixtures are considered in 50%-50% as mixture concentration. This gives the better understanding of Closed Loop Pulsating Heat Pipe performance when operated at different fill ratios and concentrations for different working fluids considered.

A Static and Dynamic Attention Framework for Multi Turn Dialogue Generation

Recently, research on open domain dialogue systems have attracted extensive interests of academic and industrial researchers. The goal of an open domain dialogue system is to imitate humans in conversations. Previous works on single turn conversation generation have greatly promoted the research of open domain dialogue systems. However, understanding multiple single turn conversations is not equal to the understanding of multi turn dialogue due to the coherent and context dependent properties of human dialogue. Therefore, in open domain multi turn dialogue generation, it is essential to modeling the contextual semantics of the dialogue history rather than only according to the last utterance. Previous research had verified the effectiveness of the hierarchical recurrent encoder-decoder framework on open domain multi turn dialogue generation. However, using an RNN-based model to hierarchically encoding the utterances to obtain the representation of dialogue history still face the problem of a vanishing gradient. To address this issue, in this article, we proposed a static and dynamic attention-based approach to model the dialogue history and then generate open domain multi turn dialogue responses. Experimental results on the Ubuntu and Opensubtitles datasets verify the effectiveness of the proposed static and dynamic attention-based approach on automatic and human evaluation metrics in various experimental settings. Meanwhile, we also empirically verify the performance of combining the static and dynamic attentions on open domain multi turn dialogue generation.

Fluid flow analysis in a closed loop pulsating heat pipe-simulation study

Thermal Management is needed very much in modern day electronics as there is complexity in the systems leading to rapid thermal management requirement. Cooling technology is the main solution for reducing heat dissipation rates. Pulsating heat pipe which consists of an heated section evaporator, cooling section condenser and an adiabatic section is one of the promising two phase heat transfer devices in the present day scenario. In the present paper a simulation study model has been modelled to analyze the distribution of fluid flow in the pipe and also the temperature variation from evaporator to condenser. A multi turn Closed loop Pulsating pipe operating with different working fluids at different fill ratios has been selected. The design consists of copper capillary tube of 2 mm and 3 mm inner and outer diameters respectively and a length of 264 mm. The liquid slugs and vapor bubbles will be observed along with the temperatures in the evaporator and condenser sections of CLPHP working with base fluids viz… water, methanol and ethanol at volume fill ratios of 50%, 60% and 75%. with a constant heat Input of 60 W. The performance parameter thermal resistance has been calculated from the difference of average temperatures for a given heat input. The temperature, thermal resistance and fill ratio graphs are drawn for comparative study of CLPHP working at different conditions for working fluids considered.

복수개의 엔코더를 이용한 다회전 앱솔루트 엔코더

A multi-turn absolute encoder is a sensor that can measure the multi-turn rotation angle of a shaft. Recently, multi-turn absolute encoders have been studied and developed for robots. In particular, the compact hollow joint structure used in cooperative robots requires a hollow multi-turn encoder with high performance and space efficiency. In this paper, we present an absolute encoder system model that consists of multiple encoders, and propose a method to compute the multi-turn rotation angle of the system. Using the proposed method, a multi turn encoder system was designed and developed for the hollow joint of the robot. The method succeeded in measuring the absolute rotation angle with a resolution of ±0.004 rad through 84 turns of the shaft.

Predicting the Effect of Field Shaper in Electromagnetic Welding Using FEM

The research work presents a 3D numerical simulation to predict the distribution of magnetic field and pressure in the desired region of the tubular jobs using coils with and without field shapers in electromagnetic welding (EMW). For finite element (FE) simulation, single-turn (ST) and multi-turn (MT) (disk type) coils are considered to analyze the effects of field shapers with varying material combinations in ANSYS MAXWELL environment. The change in magnetic field distribution on the outer peripheral region of the flyer tube along axial direction with and without field shaper is graphically shown and compared. Also, variation of magnetic pressure on the flyer tube with respect to increasing voltage and time is compared individually for various material combinations of ST/MT coil and field shaper. Results show that in welding simulation (FE) using single-turn Cu and SS coils with field shapers of Be, Nb and Ta, the magnetic pressure increases by 34, 12 and 11% and 35, 12 and 11%, respectively, as compared to the coil with no field shaper. In case of multi-turn SS coil with Cu and Be field shapers, the magnetic pressure increases by 16 and 10%, respectively. The novelty of the work is the proper guideline to select the material combinations for ST/MT coils and field shapers and positioning of work pieces inside the coil in order to achieve maximum utilization of input energy in EMW system.

Validity Testing of a Simplistic Design Version of a Kinematic Arm for Postural Measurement of Human Body Segments (May 2017)

In all engineering industries complaints about back pain and low back injuries are very high. Major factor for such back injuries are associated with Load handling tasks. In industries type of such lifting activities in percentage is to extend 77% and bending activity up to 56%.According to US department of labour report back injuries account to be 20% of all injuries and 25% of annual worker compensation goes for such injuries. So one of the important areas of Kinematic And kinetic measurements are useful is load lifting. Different methods have been evolved for carrying out Kinematic measurements, selection depend upon type of study, type of kinematic parameter to obtained merits and demerits of the methods and cost of study. Need of alternative methods which satisfy the study requirements and also compensate the cost leads to a development of "Kinematic Arm” In one of study made by Belli et al(1992) Developed Kinematic arm for three dimensional recording of human movements. They Validate and tested successfully the device. Error values for static quasi-static human motions are less than tracking system and film or video analysis ,Also device is five times cheaper than above two well known methods. Based on the guidelines of study by Belli et al a Kinematic arm has been designed and fabricated for validation testing of positional measurements of human body segments subject to different postures during load lifting. The Kinematic arm consists of four light rigid pipe linked together by three joints. One end of arm is connected to fixed reference point while other end can move freely in the three spatial directions. the free movement is allowed in all spatial directions by orientation of the axes of the three revolute joints. At each joint a potentiometer (multi turn 50 Kilo-ohm) is mounted and connected to an electronic interface to measure the angle between two link elements involved. Three potentiometers are connected in series and fed a constant current from the circuit. Output from potentiometer is amplified and measured and calibrated in terms of angles. Angles a1(t),a2(t),a3(t).measured and by appropriate trigonometric equations can calculate instantaneous position. Equation for velocity and acceleration have been established in order to evaluate the exact performance of kinematic arm for positional measurements Kinematic arm is tested for the static and quasi-static conditions for different body postures successfully. Results obtained are within the range of theoretical estimation of errors.

Inductively coupled small self resonant coil (SSRC) reader antennas for HF RFID applications

A new model of inductively coupled high frequency radio frequency identification (HF RFID) reader antennas is presented in this paper based on the idea of using the self resonance frequency (SRF) of a small multi turn coil. The introduced multi turn small self resonant coil (MT SSRC) antenna is mathematically analyzed in terms of SRF, number of turns, dimensions and dielectric characteristics of the insulation, where present. Based on the analysis, a compact planar version of MT SSRC antennas having two turns, the two turn planar SSRC (TTP SSRC), is investigated and the dependency of the SRF to the antenna dimension is observed. A TTP SSRC antenna operating at 13.56MHz is fabricated and is compared with an old model of HF RFID antennas; an optimized Q factor and a more uniform near field pattern is obtained for the new antenna. The benefits of the obtained optimized Q factor and uniform near pattern is explained for smart shelf application. Also, a number of TTP SSRC antennas operating at a distinct frequency, 13.56MHz here, are fabricated on different substrates and it is shown that the Q factor and dimension of the TTP SSRC antenna could be controlled and adjusted based on the dielectric characteristics of the substrate. The new antenna prototype has a beneficial application to smart shelf applications in HF RFID.

CFD Analysis of Multi turn Pulsating Heat pipe

Pulsating Heat Pipe (PHP) is a heat exchanger device which absorbs heat from evaporator region and transfers it to the condenser region. The flow in pipe is Multi-Phase flow. Vapour plugs and Liquid slugs are formed in PHP due to the capillary action.CFD modeling is done in ANSYS CFX with two turns of PHP and Methanol is used as the working fluid and a fill ratio of 60%. At evaporator boundary, heat flux that is equivalent to 10 W to 70 W is supplied and the condenser boundary is set as heat flux of range 4423 W/m^2 and in the adiabatic section heat flux is zero. The obtained CFD results are compared with the experimental paper [1].The CFD analysis is performed and the outputs of the simulations are plotted in graphs and contours. Decrease in the methanol temperature at the evaporator suggests that heat is carried away to the condenser part. Change in volume fractions of methanol and air in three regions viz. evaporator, adiabatic region and condenser reflects to the flow pattern of the fluid inside the PHP.

Experimental Investigation and Performance Evaluation of a Multi Turn Closed Loop Pulsating Heat Pipe

Pulsating heat pipe (PHP) is a passive heat transfer device, which transfers heat from one region to another with exceptional heat transfer capacity. It utilizes the latent heat of vaporization of the working fluid as well as the sensible heat. As a result, the effective thermal conductivity is higher than that of the conductors. An experimental study on three turn closed loop pulsating heat pipe with three different working fluids viz., Acetone, Methanol, Heptane and distilled water were employed. The PHP is made up of brass material with an inner diameter of 1.95mm, with a total length of 1150 mm for different fill ratios (FR) was employed .The PHP is tested for the thermal resistance and the heat transfer coefficient. The experimental result strongly demonstrates that acetone is a better working fluid among the working fluids considered in terms of higher heat transfer coefficient and lower thermal resistance.

Influence of process variables on the hydrodynamics and performance of a single loop pulsating heat pipe

An experimental investigation on the performance of closed loop pulsating heat pipe (CLPHP) is reported in this article. The chosen single loop geometry can be considered as the basic building block of a multi turn CLPHP. The loop with 4mm internal diameter is made of quartz glass tube to facilitate the visualization of the circulation process through the entire loop including evaporator and condenser. Temperatures measured at different locations of the loop on its wall also help to understand the complex hydrodynamics. The observation reveals different operating ranges like no flow, oscillating flow and through flow depending on the loop orientation, filling ratio and input power. There also exists an optimum filling ratio (within 50–40%) and an optimum inclination angle (within 50–70°) where the thermal resistance of the loop is the minimum. From the visualization a possible explanation for the best loop performance at a typical angle of inclination has been provided. Cease of circulation at an inclination angle close to 0° has also been visualized. Finally, a flow regime map for single loop CLPHP is presented.

High-material yield fabrication of YBCO coated conductors by Nd:YAG-PLD system

Abstract In order to fabricate superconducting coated conductors with lower cost, fabrication processes are required high material yield. We report an improvement of the material yield of YBCO films prepared by inside-plume Nd:YAG pulsed laser deposition method on metal substrates with an architecture of CeO2/LMO/IBAD-MgO/GZO/HastelloyTM. In this study, we shortened a distance from the target to the substrate ( dT-S ) in order to improve the material yield. Additionally, we have used Nd:YAG laser because initial and running costs are anticipated to be lower than those of excimer laser. As a result, by shorting the dT-S from 40 mm to 20 mm, the material yield increased on 10 mm×10 mm substrates. Additionally, by changing the O2 pressure ( P O2) from 40 Pa to 400 Pa at dT-S = 20 mm, the material yield had a local maximal value of 18.6% at P O2=200 Pa. On multi-turn (MT) metal substrates, the material yield reached 56.0%. However, the critical current density ( J c) of the YBCO film which was deposited at dT-S = 20 mm and P O2=200 Pa on the 10 mm×10 mm substrate was 1.2 MA/cm2 at the edges and 0.2 MA/cm2 at the center at 77 K in self-field, although the YBCO films showed good aligned crystal textures. In order to improve this non-uniformity, we tilted the surface normal of the target 15 degree from a line connecting target and substrate. As a result, we achieved the uniformity in deposition rate. Then, we prepared YBa1.78Cu2.9O y target to fabricate YBCO films with stoichiometric composition and obtained the uniform-high J c.

High speed production of YBCO precursor films by advanced TFA-MOD process

YBa 2Cu 3O 7− y (YBCO) long tapes derived from the metal-organic deposition (MOD) method using the starting solution containing trifluoroacetate (TFA) have been developed with high critical currents ( I c ) over 200 A/cm-width. However, high speed production of YBCO films is simultaneously necessary to satisfy the requirements of electric power device applications in terms of cost and the amounts of the tapes. In this work, we developed a new TFA-MOD starting solution using F-free salt of Y, TFA salt of Ba and Cu-Octylate for application to the coating/calcination process and discussed several issues by using the Multi-turn (MT) Reel-to-Reel (RTR) system calcination furnace for the purpose of high throughput without degradation of the properties. The coating system was improved for uniform deposition qualities in both longitudinal and transversal directions. YBCO films using the new starting solution at the traveling rate of 10 m/h in coating/calcination by the MT-RTR calcination furnace showed the values of the critical current density of 1.6 MA/cm 2 as thick as 1.5 μm at 77 K under the self fields after firing at the high heating rate in the crystallization.

Development of multi-turn reel-to-reel crystallization large furnace for high production rate of YBa 2Cu 3O y coated conductors derived from TFA–MOD process

YBa 2Cu 3O y (YBCO) coated conductors were fabricated by trifluoroacetates (TFA)–metal organic deposition (MOD) previously using a single reel-to-reel (RTR) crystallization furnace with a gas flow system parallel to the tape surface which could realize only a low production rate. In this study, we developed a new multi-turn (MT) RTR furnace with a vertical gas flow system to increase the production rate of the crystallization step and attained the uniform reaction in the tapes of the multi-turn system. We fabricated YBCO films with different conditions partial pressure of water vapor, the total pressure and the gas flow volume using the MT-RTR furnace with the vertical gas flow system, in order to investigate the influence of the processing parameters on the growth rate and the superconducting properties of the YBCO films. It was found that the growth rate of the YBCO phase film increased under the conditions of the high gas flow rate, the low total pressure and the high water vapor partial pressure. As a result, 21 times higher J c value was attained at 17 times faster growth rate than that without controlling the processing parameters in the crystallization step. This is thought to be due to the suppression of coarsening of Y 2Cu 2O 5 and CuO particles in the precursor film. Consequently, the high I c,end-to-end value of 250 A was achieved in a 5 m long tape fabricated at the production rate of 3 m/h using the only two lanes of the entire MT-RTR crystallization furnace with 10 lanes.

Beam Loss in Initial Acceleration Process of KEK Booster

Beam intensity in KEK booster decreases within one milli second to about a half of the injected. This loss is explained by the mechanism of the increasing shift of the equilibrium orbits due to the rapid growing of the momentum spread accompanied with the increase of the accelerating RF voltage. The calculation of this loss was made numerically taking into account the beam distribution in the horizontal phase space resulting from the multi turn injection, momentum distribution of the injected beam and the distribution in the RF bucket. An important point in this calculation is that the number of the particles which takes relatively large momentum deviation in the bucket is not so small as expected, for example, from a Gaussian distribution but rather large because of the rotation of the particles in the bucket due to the synchrotron motion. Therefore many particles experience rather large shift of the equilibrium orbit, which results in much loss of the beam as is observed.

Multi Turn and Single Turn Extraction from the Bonn Isochronous Cyclotron

The isochronous cyclotron at the BONN university is a multi particle variable energy machine. Its basic design is very similar to the Julich Cyclotron. The relatively low maximum energy of approx. 30 MeV deuterons and the high energy gain per turn of 220 keV results in a large turn separation of 3 mm at the extraction radius. The machine operates in the single turn extraction mode as well as in the multi turn extraction mode.