Spiral Trace Research Articles

3-D Printed Inductive Displacement/Force Sensor

This article presents a flexible inductive sensor fabricated using additive 3-D printing technology. The sensor is designed in the form of a double-spiral structure and consists of two parts: the body and the lid. The designed parts of the sensor were made of a polylactic acid (PLA) filament. Inside the body, a conductive wire is embedded. The structure is thin enough to be elastic and, therefore, it is suitable for displacement or force measurement. The structure can be easily extended, which causes the inductive coupling between the spiral traces to decrease, lowering in turn its self-inductance. When it is used as a sensor, self-inductance serves as the measure of displacement. Displacement measurements up to 26 mm with 2 mm steps were made using the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$LCZ$ </tex-math></inline-formula> meter HP4227A. Three sensor structures with an outer dimension of 4.5 cm and a varying number of spiral turns (3/4, 5/4, and 7/4) were produced and examined. The change in inductance with displacement for all three structures was modeled and analyzed. The numerical simulation was compared with the obtained experimental results, and good agreement was found (the difference is below 10%). The measurement results confirmed the efficiency of the designed sensor. Additionally, measuring respiratory rate is proposed as one of its potential applications in medicine.

Gas-powder laser cladding of coatings on steel parts in transport construction

Wear-resistant coatings solves the problem of recovering highly worn parts in transport construction. For this, various technological processes for applying metal coatings are used. One of these is laser cladding. The use of a laser beam in cladding ensures low dissolution of the base in the pad, good adhesion to the base metal, and high quality of the pad. The features of the processes of obtaining surface coatings largely depend on the type and shape of the filler material and on the methods of introducing it into the laser treatment zone. As a result of the study of the cladding of the powders, the processing modes were determined in a wide range and in the “purest” form of coating properties, i.e. without the influence of the base metal. Separate weld beads were deposited on the samples. The beam was scanned along a circular path, which left a spiral trace on the sample surface, taking into account the translational motion. Assessment of the quality of cladding and microhardness was carried out on the cross section of a metallographic section. Pores, cracks, lack of fusion, non-metallic inclusions were noted. The highest quality coatings were obtained using PG-US25 powder. The formation of the coating is of higher quality. The absence of pores and cracks in the pad is ensured when the deposited powder is mixed with the base metal (there is a kind of “dilution” of the composition with respect to carbon).

Deep-Sea Trace Fossils In The West Crocker Formation, Sabah (Malaysia), And Their Palaeoenvironmental Significance

In the “flysch” series of the West Crocker Formation (Eocene–Oligocene), Kota Kinabalu, Sabah, trace fossils are fairly common although not ubiquitous. The trace fossils commonly occur as hypichnial semi- or full-reliefs on the sole of thin turbiditic sandstone beds (mainly Bouma Tc division) in the thinly bedded heterolithic sandstone-mudstone facies interpreted as submarine fan lobe deposits. Their presence in mainly the thinly bedded facies of the fan system suggests preferential production and preservation in the fine-grained “distal” parts of the Crocker submarine fan system. Trace fossil assemblages characteristic of the Nereites ichnofacies indicate sedimentary environments mainly in bathyal to abyssal water depths (&gt;2000 m). This ichnofacies is dominated by horizontal grazing, farming and feeding traces, ranging from solitary to branching tubular burrows (Ophiomorpha, Palaeophycus and Planolites) to meandering trails and tunnels (Nereites, Cosmorhaphe, Helminthopsis), as well as the spiriform burrows Spirophycus. Graphoglyptids are the most diagnostic of the Nereites ichnofacies, produced by sediment grazers and farmers (agrichnia) and often displaying intricate networks of mainly horizontal tunnels preserved as hypichnial semi-reliefs. They include the delicate spiral traces of Spirorhaphe, as well as the enigmatic hexagonal network burrow Paleodictyon. Other ichnogenera include Planolites, Thalassinoides and Ophiomorpha which are facies-crossing and not environment specific. Detailed observations of the trace fossil assemblages and the degree of bioturbation enabled different sub-ichnofacies of the Nereites ichnofacies to be distinguished. Ophiomorpha is more common in sandy “proximal” facies and tend to penetrate deeply into pre-existing turbidite beds, its presence suggests a well-oxygenated newly deposited turbidite substrate, probably in the axial region of the fan lobes. Hence, channel axis and proximal fan deposits tend to be dominated by the Ophiomorpha rudis sub-ichnofacies. The Paleodictyon sub-ichnofacies is more typical of the lower energy lobe/fan fringe subenvironments. Proximal but off-axis areas are characterized by a mixture of the Ophiomorpha rudis and Paleodictyon sub-ichnofacies.

New insights into the early evolution of horizontal spiral trace fossils and the age of the Brioverian series (Ediacaran–Cambrian) in Brittany, NW France

AbstractIn northwestern France, the Brioverian series is a thick siliciclastic succession deposited during the Cadomian cycle (c. 750–540 Ma). In the uppermost Brioverian beds, previous studies unravelled an assemblage dominated by simple horizontal trace fossils associated with microbially stabilized surfaces. Here, we report Spirodesmos trace fossils – one-way, irregular and regular horizontal spirals – from Crozon (Finistère, Brittany), Montfort-sur-Meu and St-Gonlay (Ille-et-Vilaine, Brittany). After reviewing the literature on horizontal spiral trace fossils, an Ediacaran–Fortunian Spirodesmos pool is identified from marginal-marine to shelf settings, while an Ordovician–Recent trend formed in the deep-marine realm. These results suggest that an onshore–offshore migration in Spirodesmos took place during Ediacaran–Fortunian to Ordovician time, similar to what happened in graphoglyptids. In addition, the age of the uppermost Brioverian beds (Ediacaran or early Cambrian) is still a pending question. Here, we report two new U–Pb detrital zircon datings from sandstone samples in St-Gonlay, giving maximum deposition ages of 551 ± 7 Ma and 540 ± 5 Ma. Although these results do not discard an Ediacaran age for the uppermost Brioverian beds, a Fortunian age is envisioned because the new dating corroborates previous dating from Brittany, Mayenne and Normandy. However, the intervals of error of the radiometric dating, and the dominance of non-penetrative trace fossils associated with matgrounds (an ecology more typical of the Ediacaran Period), do not allow definitive conclusions on the age of the uppermost Brioverian beds.

Direct printing of sub-30 m liquid metal patterns on three-dimensional surfaces for stretchable electronics

In this study, a liquid metal is directly printed on various types of surfaces using an automated dispensing system. A particular class of liquid metals called eutectic gallium–indium (Ga: 75.5% In: 24.5% by weight ratio) was chosen and printed on flat, inclined (20°, 30°, 40°, and 50°), and curved ( = 0.02, 0.03, 0.04, and 0.05 mm−1) surfaces. The inner diameter of the dispenser nozzle, the distance between the nozzle tip and the surface of the substrate, turned out to be the crucial parameters that determine the performance of printing, based on the experimental evaluation of the relationship between the trace width and the parameters. We were able to control the trace width under 200 m as small as 22 m by adjusting the parameters we tested. To the best of our knowledge, an EGaIn trace 22 m in width is the smallest one achieved by direct printing of a liquid metal on three-dimensional (3D) surfaces. Also, we were able to print not only straight lines but also curved patterns, such as spiral shapes. This will lead to the miniaturization of stretchable electronics with any pattern shapes consisting of straight lines and curves. As an example of applications of the proposed method, a micro-scale pressure sensor with a spiral trace pattern was fabricated, and its performance was evaluated with loading and unloading tests. Another application of the proposed method includes direct printing of stretchable electronics on surfaces with arbitrary shapes and curvatures. It was demonstrated with a seven-segment display circuit and soft sensors printed on a mannequin hand. We believe the proposed method and its applications will open a new space in development of soft electronics and robots.

单点金刚石车削刀痕的螺旋正弦轨迹气囊抛光去除

单点金刚石车削刀痕的螺旋正弦轨迹气囊抛光去除

单点金刚石车削刀痕的螺旋正弦轨迹气囊抛光去除

单点金刚石车削刀痕的螺旋正弦轨迹气囊抛光去除

Analyses of bombardment traces on the tube head of a relativistic backward wave oscillator

In the repetitive experiments of relativistic backward wave oscillators operating at either low or high magnetic field, we found that the spiral traces appeared on the surfaces of the tube heads (entrance to the reflector and slow wave structure). Three possible causes: electrons emitted from the cathode base, cathode plasma, and cathode negative ion, are analyzed. Among them, the cathode negative ion is the most likely factor leading to the traces. The negative ions are generated by electron impact-ionization and ion impact-ionization of molecules that are desorbed from the cathode by the Ohmic heating of explosive electron emission. Due to the larger mass of negative ion, it cannot be restricted effectively by the magnetic field and will basically move along the electric field line. Many negative ions bombard the tube head with a Larmor radius of several centimeters, and the traces are connected to form spiral lines. The viewpoint of cathode negative ion current is further confirmed by the comparative experiments that show that a graphite cathode after being immersed in water for 12 h results in heavier traces, while a larger anode and cathode gap leads to slighter traces. Some suggestions are provided to reduce the production and the effect of cathode negative ion current.

The printable motor the trick is to use circuit board traces for coils - [Resources

I started out by just wanting to make a very small drone. But I quickly realized that there was a limiting factor in just how small and light I could make any design: the motors. Even small motors are still discrete packages that have to be attached to all the other electronic and structural elements. So I began wondering if there was a way to merge these elements and save some mass. • I drew inspiration from how some radio systems antennas made from the copper traces on a printed circuit board (PCB). Could I use something similar to create a magnetic field strong enough to drive a motor? I decided to see if I could build a motor of the axial flux type using electromagnetic coils fashioned from a PCB's traces. In an axial flux motor, the electromagnetic coils forming the motor's stator are mounted parallel to a disk-shaped rotor. Permanent magnets are embedded in the disk of the rotor. Driving the stator coils with alternating current causes the rotor to spin. • The first challenge was making sure I could create enough magnetic flux to turn the rotor. It's simple enough to pattern a flat spiral coil trace and run current through it, but I limited my motor to a diameter of 16 millimeters, so that the overall motor diameter was comparable to that of the smallest off-the-shelf brushless motors. Sixteen millimeters meant I could fit only about 10 turns per spiral and 6 coi ls in total, arranged under the disk of the rotor. Ten turns just isn't enough to produce a sufficient magnetic field. But the nice thing about PCBs is that it's pretty easy today to make one with multiple layers. By printing stacks of coils, with coils on each of four layers, I was able to get 40 turns per coil, enough to turn a rotor.

The numerical simulation based on CFD of hydraulic turbine pump

As the functions of hydraulic turbine pump including self-adjusting and compensation with each other, it is far-reaching to analyze its internal flow by the numerical simulation based on CFD, mainly including the pressure field and the velocity field in hydraulic turbine and pump.The three-dimensional models of hydraulic turbine pump are made by Pro/Engineer software;the internal flow fields in hydraulic turbine and pump are simulated numerically by CFX ANSYS software. According to the results of the numerical simulation in design condition, the pressure field and the velocity field in hydraulic turbine and pump are analyzed respectively .The findings show that the static pressure decreases systematically and the pressure gradient is obvious in flow area of hydraulic turbine; the static pressure increases gradually in pump. The flow trace is regular in suction chamber and flume without spiral trace. However, there are irregular traces in the turbine runner channels which contrary to that in flow area of impeller. Most of traces in the flow area of draft tube are spiral.

Effects of Dielectric Substrates and Ground Planes on Resonance Frequency of Archimedean Spirals.

Superconducting self-resonant spiral structures are of current interest for applications both in metamaterials and as probe coils for nuclear magnetic resonance (NMR) spectroscopy for high-sensitivity chemical analysis. Accurate spiral models are available in the literature for behavior of a spiral below and up to self-resonance. However, knowledge of the higher modes is also important. We present the relationships between the spiral parameters and the multiple mode frequencies of single sided spirals on dielectric substrates as modeled by method of moments simulation. In the absence of a ground plane, we find that the mode frequency has a linear though not necessarily harmonic dependence on the mode number. The effect of a thick substrate can be approximated by an effective dielectric constant. But when the thickness is less than 20% of the spiral trace width (router - rinner) this approximation is no longer accurate. We have developed a simple empirical formula to predict the higher modes.

Spiral Inductors With Floating Low-Loss RF Shields for &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$LC$ &lt;/tex-math&gt;&lt;/inline-formula&gt; Resonator Applications

A method for designing $LC$ tank circuits to improve energy efficiency and reduce layout area is described. The approach uses a projected shield that is floating, overlaps the trace of the overlying inductor, and adds capacitance to the tank’s inductor. Capacitance is distributed along the spiral traces, and the layout area is thus decreased. In this paper, we investigate the properties of spiral inductors with and without projected shielding, and compare the method with similar circuits including those with floating shields shaped as patterned ground shields. In addition, a measurement methodology for $LC$ tank resonators is developed and presented. Test structures are implemented as microstrip spiral inductors and evaluated as $LC$ tank circuits that resonate between 100 and 500 MHz. The $Q$ values of shielded structures are up to 7% greater than those without shields, and area savings for $LC$ resonators—compared with side-by-side layouts of $L$ and $C$ —are up to 35%.

An Embedded Inductor Using Sendust Powder Composite Films for Step-Up DC–DC Converter

An embedded inductor constructed with Sendust powder composite films and embedded circuits is proposed. The composite films consist of mixed Sendust flaked powders and EPDM rubber. An embedded circuit is an etched spiral copper trace with 16 turns and two layers. Copper trace is patterned with a dimension of 0.025 mm thickness, 0.1 mm width, and 0.1 mm pitch. Regarding the performances of the proposed inductor, it was obtained that the simulated inductance and copper resistance are 4.7 uH and 770 mΩ, respectively, while the measured results are 5.0 uH and 720 mQ, respectively. Measurements also show that the proposed inductor has relative high permeability and quality factor in a wide range of frequencies. It was confirmed that inductance of this inductor has a good stability to high frequency. To verify the usefulness of this inductor, the embedded inductor with a flexibility and the dimension of 10 mm × 7 mm × 0.3 mm was applied to a step-up dc-dc converter that is fabricated in the flexible printed circuit. The output power of the fabricated dc-dc converter is 1.8 W (4.5 V/400 mA), and the switching frequency is 1.2 MHz. Finally, the fabricated dc-dc converter was tested and the maximum efficiency of 84% was obtained.

Frame frequency prediction for Risley-prism-based imaging laser radar.

A dual-wedge scanner has potential applications in laser imaging radar. To realize fast scanning imaging without a blind region, the rotation rates of the wedges have to be controlled to perform beam scanning along appropriate track paths. The first-order paraxial approximation method is employed to investigate the 2D scan patterns and path density for different angular frequency ratios of the wedges rotating steadily in the same and opposite directions. The frame rate of no-blind-region scanning imaging is estimated in terms of the imaging coverage requirement. The internal relations between the rotation rates, the instantaneous field of view (IFOV), and the imaging velocity are revealed. The results show that the spiral scanning trace, resulting from co-rotating wedges, is dense in the center and sparse at the edge of the scanning field. The reverse results can be obtained for the rosette scanning trace, resulting from counter-rotating wedges. The denser the scanning trace is, the longer the scan period is. The faster the wedges rotate and the wider the IFOV is, the higher the frame rate is. When the ratio of the width of IFOV to the angular radius of the scanning field is 0.15, the frame rate of no-blind-region spiral scanning imaging can be up to 18 fps for wedge rotation rate of 12000 r/min, and that for rosette scanning imaging can be up to 20 fps.

Ray transfer matrix for a spiral phase plate

We present a ray transfer matrix for a spiral phase plate. Using this matrix we determine the stability of an optical resonator made of two spiral phase plates and trace stable ray orbits in the resonator. Our results should be relevant to laser physics, optical micromanipulation, quantum information, and optomechanics.

A Wide-Band, High Isolation UHF Lumped-Element Ferrite Circulator

A novel, spiral trace topology for a lumped-element, ferrite circulator is demonstrated in this letter. By employing this new topology, along with various optimization methods, we achieve high isolation and wide bandwidth for UHF applications. Based on simulation data, circulator isolation of 30 dB or more is possible over the 245-355 MHz frequency range. The isolation response of a fabricated spiral trace circulator exceeds 30 dB, but over a shifted and wider frequency range of 260 to 390 MHz.

An integrated inductor for high current with using Fe-Si metal alloy composite films

An integrated inductor, using 0.1 mm Fe-Si alloy composite films, has been developed with a dimension of 4.8 mm × 4.5 mm × 1.0 mm thickness. The developed inductor is structured by stacking of metal alloy composite films with μR = 19.5, which consist of mixed Fe-Si alloy powders and epoxy resin for high current application. These stacked films have an etched spiral copper trace with 9 and quarter turns for 4 layers on each film. Copper trace is patterned with a dimension of 0.07 mm thickness, 0.45 mm width, and 1 mm pitch using photolithography technology. In order to evaluate the performance of the developed inductor, inductance and DC resistance were simulated and measured. The simulated result of 1.05 μH and 83 mΩ is well coincided with measured results of 1 μH and 88 mΩ. It is also confirmed that the inductor has a high current capacity of 3 A rated and 6 A saturated values. As an application, a synchronous step down DC-DC converter using the developed inductor is fabricated with the output power of 6.6 W (3.3 V/2 A) and the switching frequency of 3 MHz. Finally, the maximum efficiency of 87% is achieved from the experiment of this DC-DC converter.

Relationship between the Seismic Coefficient and the Unfactored Geosynthetic Force in Reinforced Earth Structures

AbstractThis paper presents an integrated analytical method for calculating the resultant unfactored geosynthetic force in reinforced earth structures under seismic loading conditions. The method utilizes a pseudostatic limit equilibrium approach for assessing the internal stability of a reinforced earth structure, assuming a potential rotational failure along a log spiral trace. A closed-form solution is presented for determining the sum of all horizontal forces mobilized in the geosynthetic reinforcement along their intersection with the critical log spiral surface. This mobilized sum is then redistributed among the individual layers to determine the unfactored reinforcement forces that are needed to resist the applied seismic acceleration. Parametric studies were utilized, and the results are presented in a series of design charts for different conditions. Such charts can be used to determine the required tensile strength of the reinforcement for a given seismic coefficient. Alternatively, for a given ...

Method to Have Multilayer Thermal Insulation Provide Damage Detection

Method to Have Multilayer Thermal Insulation Provide Damage Detection

Detonability of natural gas–air mixtures

Direct initiation experiments were carried out in a 105 cm diameter tube to study detonation properties and evaluate the detonability limits for mixtures of natural gas (NG) with air. The natural gas was primarily methane with 1.5–1.7% of ethane. A stoichiometric methane–oxygen mixture contained in a large plastic bag was used as a detonation initiator. Self-supporting detonations with velocities and pressures close to theoretical CJ values were observed in NG–air mixtures containing from 5.3% to 15.6% of NG at atmospheric pressure. These detonability limits are wider than previously measured in smaller channels, and close to the flammability limits. Detonation cell patterns recorded near the limits vary from large cells of the size of the tube to spiral traces of spin detonations. Away from the limits, detonation cell sizes decrease to about 20 cm for 10% NG, and are consistent with existing data for methane–air mixtures obtained in smaller channels. Observed cell patterns are very irregular, and contain secondary cell structures inside primary cells and fine structures inside spin traces.