31—A STUDY OF POWER REQUIREMENTS IN RING SPINNING

The spinning geometry of a ring frame plays an important role, and the twist triangle is the critical region in ring spinning. Changes in the spinning geometry may affect yarn properties. This paper examines the idea of ring spinning with a "diagonal" yarn path, and the effect of such a path on yam properties, particularly hairiness. Both "left diagonal" and "right diagonal" yam arrangements are tried on a 24-spindle Cognetex FLC worsted ring frame. The hairiness results obtained from the Zweigle hairiness meter show that the right diagonal yam path produces yams of lower hairiness than the conventional ring spun yarn in almost all the hair length groups. Yam evenness and tenacity are not as sensitive to the change in yarn path. The mean spindle speed at break is also tested, and there is some deterioration in spinning efficiency with the right diagonal yarn path, particularly at higher spinning speeds. Results from this study may help explain variations in yarns spun on poorly aligned ring frames.

We carried out a set of experiments to compare three particle number concentration standards (NCSs) by calibrating the same condensation particle counter (CPC) unit (Model 3772, TSI Inc., Shoreview, MN, USA). The standards were, in the order of operation size range, the primary NCS of the National Institute of Advanced Industrial Science and Technology (AIST, Japan), the Single Charged Aerosol Reference (SCAR) (Finland), and the Inkjet Aerosol Generator (IAG) of AIST. The results obtained with the 3 standards were found to agree at all overlapping particle sizes within the uncertainty limits. The relative expanded uncertainties varied between 0.6% and 2.6%, depending on the size and standard, while the overall agreement between the standards was within 0.5%. The observed consistency of the results is an important step toward establishing internationally coherent particle NCSs. As a result, the CPC 3772 was successfully calibrated in a particularly wide size range, approximately from 10 nm to 10 μm. The re...

We developed a Digital Holographic Microscope (DHM) working with a partial coherent source specifically adapted to perform high throughput recording of holograms of plankton organisms in-flow, in a size range of 3 µm-300 µm, which is of importance for this kind of applications. This wide size range is achieved with the same flow cell and with the same microscope magnification. The DHM configuration combines a high magnification with a large field of view and provides high-resolution intensity and quantitative phase images refocusing on high sample flow rate. Specific algorithms were developed to detect and extract automatically the particles and organisms present in the samples in order to build holograms of each one that are used for holographic refocusing and quantitative phase contrast imaging. Experimental results are shown and discussed.

The ring spinning process has been used to produce fine and high quality staple fibre yarns. The stability of the rotating yarn loop (i.e. balloon) between the yarn-guide and the traveller-ring is crucial to the success and economics of this process. Balloon control rings are used to contain the yarn-loop, by reducing the yarn tension and decreasing the balloon flutter instability. Flutter instability here refers to the uncontrolled changes in a ballooning yarn under dynamic forces, including the air drag. Due to the significant variation in the length and radius of the balloon during the bobbin filling process, the optimal location for the balloon control ring is not easily determined. In order to address this difficulty, this study investigates the variation in the radius of a free balloon and examines the effect of balloon control rings of various diameters at different locations on yarn tension and balloon flutter stability. The results indicate that the maximum radius of a free balloon and its corresponding position depend not only on the yarn-length to balloon-height ratio, but also on yarn type and count. A control ring of suitable radius and position can significantly reduce yarn tension and decrease flutter instability of free single-loop balloons. While the balloon control rings are usually fixed to, and move in sinc with, the ring frame, results reported in this study suggest that theoretically, a balloon control ring that always remains approximately half way between the yarn-guide and the ring rail during spinning can lead to significant reduction in yarn tension.

The ionic plasma produced by a hypervelocity particle impact can be analysed to determine compositional informa- tion for the original particle by using a time-of-flight mass spectrometer. Such methods have been adopted on interplanetary dust detectors to perform in-situ analyses of encountered grains, for example, the Cassini Cosmic Dust Analyser (CDA). In order to more fully understand the data returned by such instruments, it is necessary to study their response to impacts in the laboratory. Accordingly, data are shown here for the mass spectra of ionic plasmas, produced through the acceleration of microparticles via a 2 MV van de Graa accelerator and their impact on a dimensionally correct CDA model with a rhodium target. The microparticle dusts examined have three dierent chemical compositions: metal (iron), organic (polypyrrole and polystyrene latex) and mineral (aluminosilicate clay). These microparticles have mean diameters in the range 0.1 to 1.6 m and their velocities range from 1-50 km s 1 . They thus cover a wide range of compositions, sizes and speeds expected for dust particles encountered by spacecraft in the Solar System. The advent of new low-density, microparticles with highly controllable attributes (composition, size) has enabled a number of new investigations in this area. The key is the use of a conducting poly- mer, either as the particle itself or as a thin overlayer on organic (or inorganic) core particles. This conductive coating permits ecient electrostatic charging and acceleration. Here, we examine how the projectile's chemical composition influences the ionic plasma produced after the hypervelocity impact. This study thus extends our understanding of impact plasma formation and detection. The ionization yield normalized to particle mass was found to depend on impact speed to the power (3.4 0.1) for iron and (2.9 0.1) for polypyrrole coated polystyrene and aluminosilicate clay. The ioization signal rise time was found to fall for all projectile materials from a few microseconds at low impact speeds (3 km s 1 ) to a few tenths of a microsecond at higher speeds (approximately 16 km s 1 for aluminosilicate particles and approximately 28 km s 1 for iron and polystyrene particles). At speeds greater than these the rise time was a constant few tenths of a microsecond independent of impact speed. The mass resolution of the time of flight spectrometer was found to be non-linear at high masses above 100 amu. It wasm=m= 5f orm= 1 amu and 40 for m= 200 amu. However, although at high masses most mass peaks had the resolution quoted, there were also occasional much narrower mass peaks observed, suggesting that at 250 to 280 amum=m= 80 to 100. The lower resolutions may be due to closely spaced mass peak signals eectively merging into one observed peak due to the (greater but still finite) resolution found for the isolated mass peaks. Complex mass spectra have been reproducibly obtained from a number of dierent projectiles that display many charged molecular fragments with masses up to 250 amu and with periodicities of 12-14 amu. These new studies reveal an extremely strong dependence of the time-of-flight mass spectra on the impact speed, particularly at low velocities (1-20 km s 1 ). In some impact velocity regimes it is possible to distinguish time-of-flight spectra originating from organic microparticles from those obtained from iron microparticles. However, such discrimination was not possible at high impact speeds, nor was it possible to distinguish between the time-of-flight spectra obtained for aluminosilicate particles from those obtained for iron projectiles.

In a reactive routing protocol such as DSR, when a route search message is flooded, a large number of nodes learn the path to the originator of the search. Moreover, each of these nodes learns paths to all upstream nodes along the route to the originator. Thus, during a route search, a large amount of topology information is distributed and stored in cache. This information is then used to reduce the number of hops future route search messages must travel. In this paper a model of the impact of topology cache is developed. The model allows the impact of cache to be estimated for a wide range of node speeds, node densities, network sizes, and values of cache timeout. When compared to simulation, the model predicts the number of hops that the route search message spreads within 10%. This model allows a wide range of analysis to be performed. For example, the paper includes an investigation of optimal cache timeout and an investigation of the impact of cache in highly mobile environments.

In a reactive routing protocol such as DSR, when a route search message is flooded, a large number of nodes learn the path to the originator of the search. Moreover, each of these nodes learns paths to all upstream nodes along the route to the originator. Thus, during a route search, a large amount of topology information is distributed and stored in cache. This information is then used to reduce the number of hops future route search messages must travel. In this paper a model of the impact of topology cache is developed. The model allows the impact of cache to be estimated for a wide range of node speeds, node densities, network sizes, and values of cache timeout. When compared to simulation, the model predicts the number of hops that the route search message spreads within 10%. This model allows a wide range of analysis to be performed. For example, the paper includes an investigation of optimal cache timeout and an investigation of the impact of cache in highly mobile environments.

The problem of sense-and-avoid for Unmanned Aircraft Systems (UAS) is genuinely multi-dimensional: there is a wide range of UAS sizes, speeds, and maneuverability, as well as missions for which these UAS will be used. There are also a variety of sensors that might be used for sense-and-avoid, which have widely varying capabilities to measure distance or angle to an obstacle, as well as closing rate, and time to collision. Most sensors are not able to provide all required information about the geometry of an encounter; therefore, using a combination of sensors offers one possible solution. We are investigating the concept that there may be a variety of possible sensor solutions for each distinct UAS capability or mission. By studying the breadth of UAS types and missions, and selectively testing certain sensors in the field, we are evaluating the limits to the capabilities of sensors and sensor combinations. This report is on the progress of this multi-dimensional evaluation. We have scoped the dimensions for evaluating UAS capabilities and the capabilities of sensors. We are experimentally evaluating sensor parameters on a variety of aircraft to validate the specified capabilities. This reports on our methodology for field evaluation of sensor technology and the lessons learned on evaluation platforms and capabilities.

Chapter 3 - Equipment

Insight into ball milling for size reduction and nanoparticles production of H-Y zeolite

Negative-salient permanent magnet motors (NSPMMs) have a potential application in the field of electric vehicles (EVs) due to their wide constant-power speed range and high efficiency. However, the researches of NSPMMs used for EVs and the relationships between the design parameters of the motor and drive performances of the EV are still absent. First, the operating characteristics of permanent magnet drive motors are investigated. Second, the relationships between the distribution of the driving cycles of the EV and the design parameters of the motor are summarized. Then, a negative-salient hybrid permanent magnet motor with excellent performances in the full-speed range and remedies for its negative impact are proposed. The electromagnetic performances of the proposed topology are compared with the conventional motor by finite element method and the performance evaluation of the electrical driving system is carried out. Finally, a prototype is manufactured and tested. The simulation and experimental results show that the proposed motor exhibits favorable characteristics such as low torque ripple, wide constant-power speed range, high efficiency in a wide speed range and low rare-earth consumption. The results verify the feasibility of the proposed topology applied to EVs.

Technology Update Advances in drilling and reaming with casing or liners (DwC, DwL, RwC, and RwL) are yielding unprecedented capabilities in well design and construction. These innovations reflect the continued evolution of a versatile system of technologies that has grown in two decades from a tool to improve efficiency and mitigate drilling hazards to a system enabling advanced wellbore construction. Advancing the Technology Modern DwC involves a suite of capabilities for drilling and reaming with either the primary string or liner. The concept has a long history. In the 1950s, the production sections of wells were drilled using tubing that was ultimately cemented in the hole without recovering the bit. Slimhole coring technology from the mining industry was tried in the 1990s in an effort to improve exploration efficiency. Over the next decade, DwC technology and versatility grew. In addition to eliminating nonproductive time (NPT) tripping drillpipe out of the hole and the associated wellbore problems, DwC emerged as an effective means of proactively mitigating wellbore instability, lost circulation, and pressure transition issues. The introduction of an integrated casing drive system in the early 2000s enabled the safe and efficient rotation, reciprocation, and circulation of the casing, which led to other benefits such as ensuring high-integrity cementing and zonal isolation. Advances in casing bit design began to resolve the inherent challenge of durability vs. subsequent drillout. With growing wellbore complexity and challenges, DwC technology evolved from discrete hazard mitigation to a larger capability well plan optimization. Greater capability advanced the end objective from solving an immediate problem to constructing a high-integrity wellbore—as designed and to the total depth (TD). The latest innovations continue this wellbore construction advance on multiple fronts. Strengthening the Wellbore Plastering has been one of the more intriguing and elusive benefits of DwC techniques. The so-called smear effect crushes cuttings against the formation to form a barrier to circulation losses and enhance wellbore stability. But achieving it on a regular, predictable basis has been difficult. Plastering occurs in some wells but not in others. A greater understanding of this process is providing the means to produce and accelerate wellbore plastering reliably, thus substantially strengthening the wellbore. The first field application of the process is planned. Research has shown that the key to plastering is the concurrence of the formation’s permeability and fracture matrix with a wide range of particle sizes in the annulus. If these factors do not correspond, plastering does not occur. The main variables are the range of particle sizes and the speed of achieving an optimal size distribution. While grinding in the casing wellbore annulus can reduce cuttings to a wide range of size over time, the delay in achieving the appropriate distribution allows time for problems to develop. Early achievement of the optimal particle distribution is critical to success.

The static recrystallization kinetics of four steels microalloyed with Nb, Ti and Nb–Ti have been investigated, covering conventional and hot direct rolling conditions. The influence of the grain size on the recrystallization time has been studied for a wide range of grain sizes (20–1000 μm). For the same deformation conditions it has been observed that the quadratic dependence on grain size works well in the range of finergrain sizes (<160 μm). In contrast, the recrystallization times measured at coarse grain sizes are significantly lower than those predicted by this dependence. However, when the whole grain size range analysed is considered, a linear dependence on grain size gives the best fit to experimental data. The effect of strain on the recrystallization kinetics has been also analysed for different initial grain sizes. It has been observed that the time to reach a 50% recrystallized fraction (t0.5) shows a dependence on strain of the type t0.5∝ε-p, the exponent being influenced by the initial grain size. A unique equation has been proposed to describe the static recrystallization kinetics of Nb, Ti and Nb–Ti microalloyed steels. The predictions of the equations have been compared to previously published data on similar steels.

To evaluate the ability of 100/Sn140 kV (Sn, tin filter) dual-energy computed tomography (CT) to differentiate urinary stone types in a patient cohort with a wide range of body sizes. Eighty human urinary stones were categorised into four groups (uric acid; cystine; struvite, oxalate and brushite together; and apatite) and imaged in 30-50-cm-wide water tanks using clinical 100/Sn140 kV protocols. The CT number ratio (CTR) between the low- and high-energy images was calculated. Thresholds for differentiating between stone groups were determined using receiver operating characteristics (ROC) analysis. Additionally, 86 stones from 66 patients were characterised using the size-adaptive CTR thresholds determined in the phantom study. In phantoms, the area under the ROC curve for differentiating between stone groups ranged from 0.71 to 1.00, depending on phantom size. In patients, body width ranged from 28.5 to 50.0 cm, and 79.1 % of stones were correctly characterised. Sensitivity and specificity for correctly identifying the stone category were 100 % and 100 % (group 1), 100 % and 95.3 % (group 2), 85.7 % and 60.9 % (group 3), and 52.6 % and 92.5 % (group 4). Dual-energy CT can provide in vivo urinary stone characterisation for patients over a wide range of body sizes. • Dual-energy CT helps assessment of urinary stone composition in vivo. • 100/Sn140 kV DECT differentiates among four stone types with 79.1 % accuracy. • In vivo diagnostic test achievable in patients with many body sizes.

A new 5-parameter MOS transistor mismatch model is introduced capable of predicting transistor mismatch with very high accuracy for ohmic and saturation strong inversion regions, including short channel transistors. The new model is based on splitting the contribution of the mobility degradation parameter mismatch into two components, and modulating them as the transistor transitions from ohmic to saturation regions. The model is tested for a wide range of transistor sizes (30), and shows excellent precision, never reported before for such a wide range of transistor sizes, including short channel transistors.