Straight Traces Research Articles

An Investigation into the Failure Characteristics of External PCB Traces with Different Angle Bends

The design of a Printed Circuit Board (PCB) involves satisfying numerous design constraints in terms of the positioning of components and the routing of conducting tracks or traces between components. One common design constraint is limiting the maximum angular bend that a trace can make (e.g. to 45°) for several potential reasons including reliability. In this paper, we systematically investigate the failure characteristics of PCB external traces with different angle bends to understand the implications in a modern context with modern PCB manufacturing processes. This involves destructive testing of straight traces with no bends, traces with only 45° bends and traces with only 90° bends. There are three aspects to the testing: (1) maximal current testing, in which the maximum current that a trace can withstand before failure is measured, (2) failure location testing for traces with bends i.e. trace failed on straight segment or at the bend, and (3) time to failure testing. We did not find a large difference between the maximum currents that can be withstood by straight traces, traces with 45° bends and traces with 90° bends. However, some of the interesting results are that traces with 45° bends are significantly more likely to fail at the location of a bend than traces with 90° bends, and straight traces take much longer to fail on average than traces with bends for a given test current.

Flexure and Twist Test Reliability Assurance of Flexible Electronics

Abstract Additively printed flexible electronics in wearable application may be subjected to twisting or flexing depending on the form factor and the intended use. There is a dearth of standards for testing and reliability assurance of flexible electronics and reliability data for various use conditions. In this paper, a test protocol has been developed for twisting and flexing on aerosol-jet additively printed flexible circuits. Test patterns with commonly used traces geometries have been developed, aerosol-jet printed, and thermally sintered at various conditions. Effect of sintering temperature on fatigue robustness in cyclic-flexing and cyclic-twisting has been studied for straight, horse-shoe, and zig-zag trace geometries. Reliability data have been acquired under both twist and flex using continuous resistance monitoring until 100,000 cycles. Failure mechanisms have been studied for both cyclic-flexure and cyclic-twist using scanning electron microscopy (SEM) and optical imaging.

Mechanics of Regular-Shape Nanomeshes for Transparent and Stretchable Devices

Abstract Open nanomesh structures with nano/micro-scale geometric dimensions are important candidates for transparent, soft, and stretchable microelectrodes. This study developed analytical and numerical mechanics models for three types of nanomeshes that consist of regular polygons and straight traces. The analytical models described the transparency, effective stiffness, and stretchability of the nanomeshes and agree with the finite element analysis. The mechanical performances of the nanomeshes are compared based on the same level of transparency. The validated analytical expressions provide convenient guidelines for designing the nanomeshes to have levels of transparency and mechanical properties suitable for bio-integrated applications.

Natural fractures at depth in the Lower Cretaceous Kuqa Depression tight sandstones: identification and characteristics

AbstractThe Kuqa Depression in the northern Tarim Basin, NW China, is characterized by fault-controlled anticlines where natural fractures may influence production. Natural fractures in the Lower Cretaceous tight sandstones in the depression have been studied using seismic profiles, borehole images, cores and thin-sections. Results show that thrust faults, two types of opening-mode macrofractures and two types of microfractures are present. Thrust faults were generated during Cenozoic N–S-directed tectonic shortening and have hydraulically linked Jurassic source rocks and Cretaceous sandstones. Opening-mode fractures can be subdivided on the basis of sizes, filling characteristics and distribution patterns. Type 1 macrofractures are barren or mainly calcite-lined. They have straight traces with widths (opening displacements) that are of the order of magnitude of 10 μm, suggesting that their primary role is that of migration channels. Type 2 macrofractures are calcite-filled opening-mode fractures. They have an elliptical or tabular shape with sharply tapering tips. Transgranular microfractures are lens-shaped and open or filled mostly by calcite; maximum widths range between 0.01 mm and 0.1 mm. Intragranular microfractures are the most common microfracture type. They are filled by calcite, feldspar or quartz. The macrofractures and transgranular microfractures have regular distributions, while most intragranular microfractures are irregularly distributed owing to their inherited origin. The results imply that natural fractures in the tight sandstones were formed as tectonic, diagenetic and natural hydraulic origins. In situ stress and cementation analyses suggest that Type 1 macrofractures and their genesis-related microfractures have controlled the present flow system of the tight sandstones.

Plate boundary localization, slip-rates and rupture segmentation of the Queen Charlotte Fault based on submarine tectonic geomorphology

Linking fault behavior over many earthquake cycles to individual earthquake behavior is a primary goal in tectonic geomorphology, particularly across an entire plate boundary. Here, we examine the 1150-km-long, right-lateral Queen Charlotte-Fairweather fault system using comprehensive multibeam bathymetry data acquired along the Queen Charlotte Fault (QCF) offshore southeastern Alaska and western British Columbia. Fine-scale analysis of tectonic geomorphology allowed us to identify and reconstruct 184 strike-slip piercing points over a 630 km stretch of the QCF. Age constraints from glacial recession and offshore sedimentation patterns yield a consistent slip-rate of ∼50–57 mm/yr since ∼17–12 ka, the fastest rate for a continent-ocean strike-slip fault on Earth. These slip-rates equal or exceed estimates of Pacific-North America (PA-NA) relative motion from global plate reconstructions, indicating that PA-NA motion is highly localized. The QCF cuts the seafloor along a narrow and unusually straight trace for its entire length and multiple fault traces are observed only at local step-overs. The geometry and behavior of the QCF over many earthquake cycles is simple and typical of mature faults with relatively homogeneous stress fields. Since the QCF is the primary PA-NA plate boundary, we used the trace of the QCF to define the small circle path for relative plate motion and computed the associated Euler pole. Predicted along-strike obliquity variations based on the new pole agree with observed tectonic geomorphology and suggest that previous global plate reconstructions overestimated the degree of oblique convergence along the QCF. We also find that subtle, long-wavelength (75–150 km) bends and discrete step-overs appear to define the endpoints of M>7 earthquakes, suggesting that obliquity and resultant fault geometry may control rupture segmentation and asperity development. Lastly, the agreement between predicted obliquity and tectonic geomorphology along the entire length of QCF compelled a reevaluation of regional tectonic models. In the north, the eastern Yakatat Terrane appears to be translating northwest with the Pacific plate, and slip transferred from the QCF to the Fairweather Fault results in ∼20 mm/yr of convergence along the southern St. Elias mountains. In the south, we predict a reduced rate of convergence along the QCF west of Haida Gwaii (∼5–6 mm/yr of shortening, on average) relative to previous studies. Our results support a model for transpression and strike-slip partitioning along the edge of a hot and weak Pacific Plate, leading to crustal thickening and growth of the Queen Charlotte Terrace to the west of Haida Gwaii.

Fully 3D-printed carbon nanotube field emission electron sources with in-plane gate electrode

We report the design, fabrication, and experimental characterization of the first fully additively manufactured carbon nanotube (CNT) field emission electron sources. The devices are created via direct ink writing (DIW)—one of the least expensive and most versatile additive manufacturing methods, capable of creating monolithic multi-material objects. The devices are 2.5 cm by 2.5 cm glass substrates coated with two imprints, i.e. a trace made of a CNT ink (the emitting electrode), symmetrically surrounded on both sides by a trace made of Ag microparticle ink (the in-plane extractor gate). The CNT ink is a mixture of (–COOH)-functionalized multiwalled CNTs (MWCNTs), N,N-Dimethylformamide, and ethyl cellulose. Optimization of the formulation of the CNT ink resulted in a MWCNT concentration equal to 0.82 wt% and in imprints with an electrical resistivity equal to 0.78 Ω cm. 3D-printed devices having CNT imprints with active length equal to 25 mm (a single, straight trace with 174.5 μm gap between adjacent Ag microparticle imprints) and 135 mm (a square-loop spiral with 499 μm gap between Ag microparticle adjacent imprints) were characterized in a triode configuration (i.e. using an external anode electrode) at ∼2.5 × 10–7 Torr, yielding emission currents as large as 120 μA (60 μA cm−2), start-up voltages as low as 62 V and gate transmission as high as 99%. The low-cost cold cathode technology is compatible with compact applications such as miniaturized mass spectrometry, handheld x-ray generation, and nanosatellite electric propulsion.

Reconstruction of Equivalent Emission Sources for PCBs From Near-Field Scanning Using a Differential Evolution Algorithm

An efficient method to extract equivalent radiated emission sources for printed circuit boards (PCBs) from near-field (NF) scanning data is presented. The equivalent sources are represented by elemental magnetic dipoles placed over a planar surface on the component side of a PCB. A global optimization procedure, based on the differential evolution algorithm, is used to determine the components of each dipole moment, by exploiting only the magnitude of the scanned NF data. The number and positions of the equivalent dipoles are predetermined by analyzing the scanning NF data, which is based on the NF radiation pattern of a single straight trace on a PCB. The effects of both of the spacing of the scanning points and the distance between the scanning and the reconstruction planes on the accuracy of the reconstructed results are studied. The proposed method is validated by the comparison of the reconstructed and full-wave results for PCBs with different types of traces.

A Trade Street of a Small Town as a Public Space(by the Example of Nizhny Novgorod Region)

Located round Nizhny Novgorod one of thelarge commercial and industrial centres of the Povolzhie (the Volga region), these towns possess their own regional specific character determined by the historically developed trade and craft traditions. The location of the main trade street in the town generallayout its relation to the transportation scheme, its planning, housing, architectural dominants, transformations and losses, today's state are studied for each town. Various types of trade streets built in thelate XVIII - early XX centuries are shown: a street-corridor with straight tracing and continuous masonry housing (Gostinny Ryad street in Arzamas), a street with direct tracing and dispersed masonry and masonry-wooden housing (Bolshaya Sovetskaya street in lyskovo), a street with curved picturesque tracing and continuous masonry housing (Nizhegorodskaya street in Pavlovo), space formed by three streets with a multiraw arrangement of continuous masonry buildings (Gorky street Bolshoy Kirovskiy sezd Kooperativny sezd in Gorodets). Two types of today's existence of historically formed trade streets of a smalltown are revealed i.e. an active use (Arzamas, Pavlovo) and stagnation (Lyskovo, Gorodets).Main problems of trade streets' modern use and conditions under which these streets may become valuable public spaces in contemporary understanding of this meaning are identified based on studying historical-culturat natural-ecologicat social-economic, architectural and town-planning criteria of assessment of trade streets' viability in modern conditions and ascertaining potential of their development related to the high historical-cultural value of such complexes.

BULLDOZING AND RESTING TRACES OF FRESHWATER MUSSEL ANODONTA WOODIANA AND SUBSTRATE CHARACTERISTICS IN LAKE-MARGIN AND RIVER SETTINGS OF UMBRIA, ITALY

The neoichnology of the freshwater mussel Anodonta ( Sinanodonta ) woodiana (Lea, 1834) is examined herein in some continental environments of Umbria (central Italy), such as lake-margin and river dam-margin settings. This study, based on analysis of about 200 traces, reveals that this mussel burrows employing two types of behaviours: bulldozing which produces horizontal meanders to straight bilobate traces, often filled with peloidal faecal pellets (pseudofaeces and backfill), and resting (vertical stationary into substrate) while filter feeding. A new type of very soft substrate, the ‘cloudground’ is proposed. It is placed at the water-sediment interface, above the soupground. After four years of observation, the cloudground was buried with shells and traces, preserving through the fossilization barrier about 20% of the Anodonta traces. This bivalve activity is a useful tool to recognize preservation of mud in quiet environments and parallels ichnological evidence of unknown epichnial trace fossils in the continental realm. Cloudground with resting traces must be investigated also in modern marine basin floor environments where cloud of mud dominates and considered also in geological record.

A Fuzzy Path Preview Algorithm for the Rice Transplanting Robot Navigation System

Path preview is the key to realizing automatic navigation control that can guide the navigational direction of the vehicle trace. The preview point must be regulated dynamically according to the predetermined navigational features of the actual path preview control to obtain the ideal path trace result. Based on the “preview follower theory” combined with the driver’s experience and utilizing the Matlab (The MathWorks, Inc., Natick, Massachusetts, USA) fuzzy control toolbox, a fuzzy algorithm of the preview point has been proposed in the paper. The navigation control system embedded in the path planning and preview control algorithm has been applied in the experiment to trace a predetermined navigational straight way, 90°curve and arc way to operate a rice transplanting robot. The results showed that the lateral DRMS (distance root mean square error) of the straight trace is approximately 0.33 m, and the maximum error is approximately 0.71 m; the lateral DRMS of the 90°curve trace is approximately 0.73 m, and the maximum error is approximately 1.85 m; the lateral DRMS of the arc way trace is approximately 1.03 m, and the maximum error is approximately 2.56 m; and the total mean error is approximately 0.6 m. According to the outcome of the experiment, the relevant algorithm can basically meet the requirements of rice transplanting robot guidance.

Ground Surface Ruptures and Near‐Fault, Large‐Scale Displacements Caused by the Wenchuan Ms8.0 Earthquake Derived from Pixel Offset Tracking on Synthetic Aperture Radar Images

Abstract:The 12 May 2008 Wenchuan Ms8.0 earthquake produced surface displacements along the causative fault, the Yingxiu‐Beichuan Fault, which are up to several meters near the fault. Because of the large gradient, satellite synthetic aperture radar (SAR) interferometric data are strongly incoherent; the usual SAR interferometry method does not allow such displacements to be measured. In the present study, we employed another approach, the technique based on pixel offset tracking, to solve this problem. The used image data of six tracks are from the Advanced Land Observing Satellite, Phased Array type L‐band Synthetic Aperture Radar (ALOS/PALSAR) dataset of Japan. The results show that the entire surface rupture belt is 238 km long, extending almost linearly in a direction of 42° north–east. It is offset left laterally by a north–west‐striking fault at Xiaoyudong, and turns at Gaochuan, where the rupture belt shifts toward the south by 5 km, largely keeping the original trend. In terms of the features of the rupture traces, the rupture belt can be divided into five sections and three types. Among them, the Beichuan–Chaping and Hongkou–Yingxiu sections are relatively complex, with large widths and variable traces along the trend. The Pingtong–Nanba and Qingping–Jingtang sections appear uniform, characterized by straight traces and small widths. West of Yingxiu, the rupture traces are not clear. North of the rupture belt, surface displacements are 2.95 m on average, mostly 2–3.5 m, with 7–9 m the maximum near Beichuan. South of the rupture belt, the average displacement is 1.75 m, dominated by 1–2 m, with 3–4 m at a few sites. In the north, the displacements in the radar line of sight are of subsidence, and in the south, they are uplifted, in accordance with a right‐slip motion that moves the northern wall of the fault to the east, and the southern wall to the west, respectively. Along the Guanxian–Jiangyou Fault, there is a uplift zone in the radar line of sight, which is 66 km long, 1.5–6 km wide, and has vertical displacements of approximately 2 m, but no observable rupture traces.

Application research of image fusion in ultrasonic tomography of concrete

To comprehensively utilize the inversion results of different parameters, the image fusion algorithm based on wavelet transform was adopted to synthesize the images by straight ray tracing and bend ray tracing. The application example shows that the image fusion can effectively integrate the image information. And the fusion rule can significantly reduce background noise and highlight the defect details, which is suitable for the concrete ultrasonic tomography image.

Surface deformation during the Mw 6.4 (8 June 2008) Movri Mountain earthquake in the Peloponnese, and its implications for the seismotectonics of western Greece

The Movri Mountain earthquake (Mw 6.4), western Greece, was likely caused by dextral‐slip along a blind high‐angle fault, and generated a complex pattern of co‐seismic surface ruptures southwest of the Gulf of Corinth. The mapped Nisi, Michoi, and Vithoulkas rupture segments have similar lengths (5–6 km) and vertical offset on the order of 25, 10, and 5 cm, respectively. They are commonly expressed as straight or jagged linear traces with secondary cracks radiating from the main segments. Horizontal slip vector analysis indicates extensional faulting processes for all rupture segments. Although these faults exert some control on the fluvial drainage pattern and at least one of them was ruptured during past events, their escarpments are poorly preserved. The indistinct topographic expression of the studied faults and their complex rupture patterns can be attributed to the distribution of the deformation over a blind fault.

Radio tracking of the interplanetary coronal mass ejection driven shock crossed by Ulysses on 10 May 2001

We report on the detection of type II radio emission which was observed for more than a day prior to the arrival of an interplanetary shock at Ulysses. We use local spectral emission peaks, computerized from time‐averaged intensity spectra of the type II burst, to track the associated emitting shock. In the spectrogram plotted as a function of time and inverse frequency, these peaks appear as elongated clusters of data points, organized in fundamental‐harmonic bands and delineating drifting emission features. Least squares linear fittings to identified clusters give straight traces with different slopes. Most of these, when extrapolated to the Sun, are found to converge nearly at the same starting time, allowing determination of the average shock speed. Shortly before the shock crossing, intense Langmuir waves were detected at the electron plasma frequency upstream of the shock. This plasma wave enhancement together with the radio emission observed predominantly at the harmonic of the plasma frequency, all point to the occurrence of the type II radio source region in the upstream electron foreshock. We have accurately substracted the thermal noise background from the observed emission intensity to deduce the type II brightness temperatures at the fundamental and harmonic near the shock crossing. The measured brightness temperature of the type II harmonic emission is found to peak at a value of ≃3 × 1013 K just after the shock crossing; just before, the harmonic brightness temperature is ≃1012 K and the fundamental brightness temperature ≃8 × 1011 K.

A complex seismogenic shear zone: The Düzce segment of North Anatolian Fault (Turkey)

This work highlights how surface geological data can integrate and complete a fault characterization including its seismogenic depth. We investigated the area struck by the November, 1999, Mw 7.1 earthquake that ruptured the Düzce segment of the North Anatolian Fault Zone (NAFZ) after the August, 1999, Mw 7.4 Izmit earthquake. To explore the persistency or evolution of the active fault setting at the surface, we compared detailed coseismic surface expressions with the long-term morphology and structural architecture of the Düzce zone. We identified a simple 1999 coseismic fault trace (CFT) and an older complex fault system (RFS) involving a wider zone of deformation. Two different parts of the Düzce segment were recognized. A western section presents a staircase trajectory of the coseismic fault trace that reactivated part of the older fault system. An eastern section presents a straight coseismic fault trace that cross-cuts the older and complex fault system. The western Düzce fault segment splays out from the Izmit counterpart of the NAFZ, forming a releasing fault junction. By comparing a model of its coseismic surface deformation field with the long-term morphology, we observed that the present topography of this western section results from the NAFZ activity by repeating coseismic deformations like those in 1999. The mechanical interaction in the release fault junction produces local transtension across the western Düzce fault and justifies its stable complexity. It does not evolve into a straight trace. The surface boundary between the Düzce fault sections also separates at depth two fault sections: one with low slip to the west, and another with a big asperity to the east. Thus, the Izmit/Düzce interaction (1) may produce an unfavorable setting for a build-up of asperities in the western Düzce segment and (2) could delay the propagation of the Izmit rupture along the Düzce segment that nucleates mainshocks only on its eastern section. In other words, the arrangement of the fault junction may permanently control how the two sections of the Düzce fault behave and rupture.

Reducing Warpage of Printed Circuit Boards by Using Wavy Traces

Printed circuit boards (PCB’s) often warp when subjected to temperature changes, associated with either the manufacturing process or the usage. In order to reduce the warpage, waviness was introduced in the electric traces. Model PCB’s were manufactured and tested. The elastic stiffnesses of the PCB’s were determined using a coupled experimental-analytical vibration method, whereas coefficient of thermal expansions (CTE’s) and warpage were measured by placing strain-gage instrumented specimens in an environmental chamber and varying the temperature. Unit cell finite element (FE) analyses of PCB’s with both straight and wavy traces were performed to predict thermoelastic behavior. Both experimental tests and numerical analyses conclude that the PCB’s with wavy traces warped approximately 40% to 60% less than the PCB’s with straight traces.

Effects of cohesive zones on small faults and implications for secondary fracturing and fault trace geometry

Fracture mechanics theory and field observations together indicate that the shear stress on many faults is non-uniform when they slip. If the shear stress were uniform, then: (a) a physically implausible singular stress concentration theoretically would develop at a fault end; and (b) a single curved ‘tail fracture’ should open up at the end of every fault trace, intersecting the fault at approximately 70 °. Tail fractures along many small faults instead range in number, commonly form behind fault trace ends, have nearly straight traces and intersect a fault at angles less than 50 °. A ‘cohesive zone’, in which the shear stress is elevated near the fault end, can eliminate the stress singularity and can account for the observed orientation, shape, and distribution of tail fractures. Cohesive zones also should cause a fault to bend. If the cohesive zone shear stress were uniform, then the distance from the fault end to the bend gives the cohesive zone length. The nearly straight traces of the tail fractures and the small bends observed near some fault ends implies that the faults slipped with low stress drops, less than 10% of the ambient fault-parallel shear stress.

Shear zones formed along long, straight traces of fault zones during the 28 June 1992 Landers, California, earthquake : A. M. Johnson, R. W. Fleming & K. M. Cruikshank, Bulletin - Seismological Society of America, 84(3), 1994, pp 499–510

Shear zones formed along long, straight traces of fault zones during the 28 June 1992 Landers, California, earthquake : A. M. Johnson, R. W. Fleming & K. M. Cruikshank, Bulletin - Seismological Society of America, 84(3), 1994, pp 499–510

Shear zones formed along long, straight traces of fault zones during the 28 June 1992 Landers, California, earthquake

Abstract Surface rupturing during the 28 June 1992 Landers, California, earthquake, east of Los Angeles, accommodated right-lateral offsets up to about 6 m along segments of distinct, en-echelon fault zones with a total length of 80 km. The offsets were accommodated generally not by faults—distinct slip surfaces—but rather by shear zones, tabular bands of localized shearing. Along simple stretches of fault zones at Landers the rupture is characterized by telescoping of shear zones and intensification of shearing: broad shear zones of mild shearing, containing narrow shear zones of more intense shearing, containing even narrower shear zones of very intense shearing, which may contain a fault. Thus the ground ruptured across broad belts of shearing with clearly defined, subparallel walls, oriented NW. Each broad belt consists of a broad zone of mild shearing, extending across its entire width (50 to 200 m), and much narrower (a few meters wide) shear zones that accommodate most of the offset of the belt and are portrayed by en-echelon tension cracks. In response to right-lateral shearing, the slices of ground bounded by the tension cracks rotated in a clockwise sense, producing left-lateral shearing, and the slices were forced against the walls of the shear zone, producing thrusting. Even narrower shear zones formed within the narrow shear zones. Although these probably are guides to right-lateral fault segments below, the surface rupturing during the earthquake is characterized not by faulting, but by the formation of shear zones at various scales.

Identification of Wrench Faults Using Subsurface Structural Data: Criteria and Pitfalls (1)

Many structures imaged with reflection seismic can resemble a wrench fault system because of the great structural diversity of strike-slip faults and the wide range of contractional and extensional features associated with these faults. Because of these resemblances, numerous faults are misidentified as wrench faults by workers using subsurface structural data. Credible identification requires combinations of profile and map criteria: (1) narrow, long, straight, throughgoing, solitary master fault or zone of deformation, (2) steep to moderate dip of the master fault at depth, (3) offset of the top of basement, (4) changes in relative upthrown side, separation sense, and/or fault dip direction at depth or along the strike of the master fault, (5) narrow fault slices within the master fault zone that steepen and join at depth (negative and positive flower structures), (6) different separation sense and orientation of relative upthrown side at these fault slices, and (7) coeval, en echelon flanking structures. The identification should be confirmed with other criteria that refute alternative interpretations. The main pitfalls to a reliable identification are not considering alternative structural styles and the misinterpretation of features or patterns that superficially resemble wrench systems. The profile geometries of basement-involved reverse or normal faults, particularly those with structural inversion, can resemble the single strand of convergent or divergent wrench faults. Profile geometries of flower structures can be mimicked by narrow contractional horsts or narrow extensional grabens, complexly faulted anticlines or synclines, splay faults, fault zones intruded by salt or shale, and overprinted structures. Pitfalls in interpreting map relationships are possible when structural patterns combine several tectonic influences, are controlled by rock anisotropy, or include elements hat are not coeval, and if the patterns characteristic of other styles are misinterpreted. Many erroneous identifications of wrench faults can be eliminated by demonstrating that the investigated fault or feature lacks a straight trace, lateral length, or throughgoing continuity.