Overlap Zone Research Articles

Single-strap adhesively bonded joints with square or tapered adherends in tensile test conditions

In order to ensure efficiency, safety and reliability of bonded joints, an adequate understanding of their behaviour is necessary. This work focuses on the evaluation of the deformations and stresses in adhesively bonded single-strapped joints based on a novel analytical solution, adequate both for square and tapered adherends, and by using linear or nonlinear finite element analyses. The calculus models are validated experimentally by strain gauge measurements and by using the digital image correlation method. Tensile tests are simulated analytically and numerically in order to emphasise the influence of some parameters as: the length of the outer and inner adherends, the relative length of the overlap zones, the joint eccentricity and the rigidity of the adherends. A comparison between results obtained for single-strapped joints in tension for clamped or simply supported ends is also presented.

Numerical modeling of steady-state flow of a non-Newtonian power-law fluid in a rough-walled fracture

Numerical simulations of power-law fluid flow in a rough fracture of regular or irregular topography were carried out using the finite-volume method under the assumptions of the lubrication theory approximation. The model was verified by comparing its results with analytical results available for regular 1D sinusoidal profiles across or along the flow. For a regular profile with sinusoidal variation of the aperture in both directions, the model confirmed that a geometric average can be used as a first approximation, as long as the variation in the profile is not too large. For all fracture topographies studied, reducing the exponent, i.e. making the fluid more shear-thinning, resulted in increasing equivalent hydraulic aperture. The normalized equivalent hydraulic aperture decreased with the normalized standard deviation of the fracture aperture for all fracture topographies studied, except a fracture with a large-scale feature representing a zone of overlap in the middle of the fracture. The validity of the assumptions made in the numerical simulations, in particular the lubrication theory approximation, is discussed and the directions for future work are outlined in conclusion.

PACIAE 2.1: An updated issue of the parton and hadron cascade model PACIAE 2.0

We have updated the parton and hadron cascade model PACIAE 2.0 for relativistic nuclear collisions (cf. Comput. Phys. Comm. 183(2012)333) to the new issue of PACIAE 2.1. The PACIAE model is based on PYTHIA. In the PYTHIA model, once the generated particle/parton transverse momentum $p_T$ is randomly selected, its component of $[p_x,p_y]$ was originally put on the circle with radius $p_T$ randomly. It is now replaced by put on the circumference of ellipse with half major and minor axes of $p_T(1+\delta_p)$ and $p_T(1-\delta_p)$, respectively, in order to investigate better the transverse momentum anisotropy in final hadronic state.

Effect of the Metal Block on the Stress Distributed in the Adhesively Bonded Single Lap Steel Joint

The effect of 4 mm long metal block bonded to the end of the overlap zone on the stress distributed in adhesively bonded single lap steel joint was investigated using elasto-plastic finite element method (FEM). The results from the numerical simulation showed that the stress is varied a little when the joints with a couple of 4 mm long metal block adhered to both ends of the over lap or with a couple of adhesive fillet. Compared to the joint without the metal block, it is advantageous of reducing the peak stress in the adhesive layer near the ends of the lap zone in adhesively bonded single lap steel joints but its effect is less than that of the joint with a couple of adhesive fillet. There is no evidential difference in the effects between the steel and aluminum block.

Sex difference in the communicatory significance of localized defecation sites in Arabian gazelles (Gazella arabica)

Mammalian scent marking in localized defecation sites (latrines) has often been interpreted in the context of (male) territory defense. However, latrines could have different functions in males and females, especially where territorial males monopolize groups of females with stable social alliances and pronounced home range overlap. We investigated the communicatory significance of latrines in wild Arabian gazelles (Gazella arabica) and assessed the spatial distribution of latrines within home ranges. Latrine density and utilization was highest in the center of female group home ranges, and less frequent in peripheral home range sections, pointing towards communication within groups rather than towards territoriality. When considering male home ranges, latrine densities and utilization were higher in non-overlap zones, contradicting a territorial function. This pattern appears to be caused by more females than territorial males per given area establishing latrines. A subsequent survey of latrine utilization, based on camera trapping, suggests that males use latrines for territory defense: males visited latrines in overlap zones disproportionally more often than females, and successions of two males prevailed. Our study thus highlights that male territorial marking can be masked when males and females use the same marking system for different purposes.

GHOSTLIER DEMARCATIONS

This memoiristic essay is a contribution to the Common Knowledge symposium titled “Fuzzy Studies: On the consequence of blur.” While probing his personal memories and making a case for devaluing our intellectual constructs, the author, an anthropologist, examines paintings by Paul Cézanne and Pieter Bruegel, poems by Wallace Stevens and W. H. Auden. The essay argues that each self-deluding “reality” we construct is only temporary, destined to fall back into the elusive, undifferentiated zone of overlap and ambiguity from which it has emerged. Therefore, the author urges, we should temper the intellectual “rage for order” with an openness to chaos and contingency, along with sustained and careful attention to creative works and religious practices in which the mind appears to grasp its limits. In this way, we may substitute what Stevens called “ghostlier demarcations” for our clear, exact, and self-deceptive certainties.

Effect of Metal Block on Stress Distribution in Weld-Bonded Steel Joint

The effect of metal block as the fillet on the stress distributed in weld-bonded single lap steel joint was investigated using elasto-plastic finite element method (FEM). The results from the numerical simulation showed that it is beneficial when the joints with a couple of right triangle metal block were adhered to both ends of the over lap. It is advantageous of reducing the peak stress in the adhesive layer near the ends of the lap zone in weld-bonded single lap steel joints so that the stress distribution in overlap zone was improved. The load-bearing capacity of the weld-bonded single lap steel joints may be elevated. There is no evidential difference in the effects between the steel and aluminum block.

P-T-t conditions, Nd and Pb isotopic compositions and detrital zircon geochronology of the Massabesic Gneiss Complex, New Hampshire: Isotopic and metamorphic evidence for the identification of Gander basement, central New England

We present new evidence for the assignment of the Neoproterozoic Massabesic Gneiss Complex of New Hampshire to the Gander terrane rather than the Avalon terrane. The majority of Avalonian (*sensu stricto*) igneous and meta-igneous rocks as defined in Maritime Canada have positive whole-rock ɛ~Nd~ compared to more negative values for Gander rocks, although there is a region of overlap in ɛ~Nd~ between the two terranes. Our samples from areas in Connecticut previously thought to be Avalonian and samples from the Willimantic dome have the same isotopic signatures as Maritime Canada Avalon. In contrast, samples from the Clinton dome of southern Connecticut plots exclusively in the Gander field. The majority of the orthogneiss samples from Lyme dome (coastal Connecticut), Pelham dome (central Massachusetts) and Massabesic Gneiss Complex also plot in the Gander field, with a few samples plotting in the overlap zone between Gander and Avalon. U-Pb age distributions of detrital zircon populations from quartzites from the Massabesic Gneiss Complex more closely approximate the data from the Lyme Dome rather than Avalon. Additionally, the similarity of the P-T-t path for the rocks of the Massabesic Gneiss Complex (established by thermobarometry and ^40^Ar/^39^Ar dating of amphibole, muscovite, biotite and K-feldspar) with that established in the Ganderian Lyme dome of southern Connecticut strengthens the assignment of these rocks to a single Gander block that docked to Laurentia during the Salinic Orogeny. The identification of Ganderian isotopic signatures for these rocks all of which show evidence for Alleghanian metamorphism, supports the hypothesis that Neoproterozoic Gander lower crustal rocks underlie southern New Hampshire, Massachusetts, and Connecticut, and that all rocks of the overlying Central Maine trough that largely escaped high-grade Alleghanian metamorphism are allochthonous. We suggest that during the Alleghanian, the docking of Gondwana caused Avalon to wedge into Gander, metamorphosing and partially melting the Massabesic Gneiss Complex to the observed P-T-t conditions, with the complex forming an uplifted sheet that was back-thrusted over the Avalonian wedge.

Cytogeography of Oxalis pes-caprae in its native range: where are the pentaploids?

Due to its instantaneous effects on the genetics, phenotype, physiology and/or ecology of a plant, polyploidy can play an important role in facilitating plant invasions. Understanding the determinants of invasiveness in species with multiple ploidy levels requires a detailed knowledge of ploidy composition in native versus invaded ranges. Using DNA flow cytometry, we performed representative ploidy screening (277 localities, 333 individuals) across the native range of Oxalis pes-caprae and compared the data with those from invaded ranges. Both ranges showed striking differences in ploidy composition: whereas tetra- and especially pentaploids successfully colonized secondary areas, only di-, (very rare) tri- and tetraploids (dominant) were found in the native range of this species. Disregarding the diploid var. sericea, diploids and tetraploids of the nominate variety showed largely parapatric distribution in the native range, with a zone of overlap in the Northern Cape Province. Our results challenge the conventional scenario of the introduction of pentaploid individuals from the Greater Cape Floristic Region. The origin of the pentaploid cytotype is unclear and molecular tools applied in a large scale screening are needed to understand the invasion history of the species.

Chilled but not frosty: understanding the role of climate in the hybridization between the Mediterranean Fraxinus angustifolia Vahl and the temperate Fraxinus excelsior L. (Oleaceae) ash trees

AbstractAimTo examine mechanisms related to the formation of hybrid zones between the Mediterranean narrow‐leaved ash tree Fraxinus angustifolia Vahl and the common ash Fraxinus excelsior L., a mostly temperate tree species, at the continental scale.LocationTemperate and Mediterranean Europe and the western part of the Black Sea basin.MethodsWe used species distribution models to determine the potential zones of sympatry between the two species, which remain largely unknown. In addition, we analysed 58 populations and 456 samples of ash tree that spanned most of the distribution of the two species across Europe, and included both parental species and selected hybrid populations. Levels of hybridization in the 58 populations were estimated using 19 nuclear microsatellite loci, including six anonymous nuclear single sequence repeat (SSR) markers and 13 recently developed single sequence repeats from expressed RNA sequence tags (EST‐SSRs).ResultsBayesian assignment supported the notion of two separate gene pools regardless of the type of marker used, which suggest an ancient population structure. Populations located within the predicted overlap zones had intermediate levels of admixture with a tendency for hybrid populations to occur towards temperate areas. Selection analyses indicated that six of the EST‐SSRs had been subjected to stabilizing selection whereas two others had been subjected to directional selection. Results of spatial filtering on the allele frequencies of the loci under directional selection suggest that the number of days of frost and summer temperatures are both ecological factors that can limit the extent of the hybrid zone. Moreover, areas associated with known or predicted hybrid zones showed abrupt changes in allele frequencies compared with the periphery of the distributions.Main conclusionsOur analyses suggest that the hybrid structure in these closely related ash species is ancient and asymmetric and that climate‐driven selection, in particular cold weather, can potentially limit the extent of hybrid populations.

Spatial analysis of the back reflected laser light during CO2-laser cutting of metal sheets

During laser material processing such as laser welding or cutting, it is known that the whole laser power is not only absorbed in or transmitted through the interaction zone, but a significant percentage is also reflected back to the laser source. Some publications analyzing the laser welding process showed a clear correlation between the reflected laser power and the result of the process. In this report, the authors analyze the information content of back reflected laser light during the high-power CO2-laser cutting of metal sheets. For this purpose, laser reflections are detected coaxially via a scraper-mirror online during laser cutting with a high time resolution. For different materials (mild steel, stainless steel, aluminum) and thicknesses (1 and 3 mm), a detailed spatial analysis on where the laser beam is reflected from (cutting front or workpiece surface) will be given. The spatial analysis of the reflected laser light shows that only 10% is reflected from the cutting front in the kerf. The main part (>90%) is reflected from the overlap zone of the laser beam with the workpiece surface outside the cutting kerf. Therefore, the signal strongly depends on the surface roughness of the treated material. It will be shown that, as expected, reflective surfaces with little roughness show higher CO2-laser reflections than rough surfaces with a higher level of roughness. Furthermore, the fraction of back reflected laser light increases with higher cutting feed rate which can be explained with a larger overlapping zone of the CO2-laser beam with the workpiece surface in front of the cutting kerf. In addition, the back reflection signal also strongly depends on the position of the focal plane with respect to the workpiece surface. This relationship can be used to measure the absolute position of the focal plane in-process as well as detecting an undesired focus shift during laser cutting.

A classification scheme for ventricular arrhythmias using wavelets analysis

Identification and classification of ventricular arrhythmias such as rhythmic ventricular tachycardia (VT) and disorganized ventricular fibrillation (VF) are vital tasks in guiding implantable devices to deliver appropriate therapy in preventing sudden cardiac deaths. Recent studies have shown VF can exhibit strong regional organizations, which makes the overlap zone between the fast paced rhythmic VT and VF even more ambiguous. Considering that implantable cardioverter-defibrillator (ICD) are primarily rate dependent detectors of arrhythmias and that there may be patients who suffer from arrhythmias that fall in the overlap zone, it is essential to identify the degree of affinity of the arrhythmia toward VT or organized/disorganized VF. The method proposed in this work better categorizes the overlap zone using Wavelet analysis of surface ECGs. Sixty-three surface ECG signal segments from the MIT-BIH database were used to classify between VT, organized VF (OVF), and disorganized VF (DVF). A two-level binary classifier was used to first extract VT with an overall accuracy of 93.7% and then the separation between OVF and DVF with an accuracy of 80.0%. The proposed approach could assist clinicians to provide optimal therapeutic solutions for patients in the overlap zone of VT and VF.

Research on the static strength performance of adhesive single lap joints subjected to extreme temperature environment for automotive industry

Adhesive bonding technique is widely studied and adopted in automotive industry in recent years, which leads to satisfactory joint mechanical properties and lightweight effects. In this study, the static mechanical performance of adhesively bonded joints after different temperature exposures was investigated through joint quasi-static shear-strength test. A response surface method using MATLAB programming was utilised to analyse the influences of exposure temperature and adhesive mechanical attributes on joint static strength. Visual inspection and scanning electron microscopy were later performed on the fracture surfaces to explain the failure mechanisms. Test results showed that long-term temperature exposure caused degradation in joint strength and failure displacement. It was found through response surface curve that comparing to higher temperature exposure, lower temperature causes greater and faster environmental degradation. Different types of fracture surfaces in the overlap zone were also detected through comparing adhesive joints under different environmental treatments.

Brief communication: New Y-chromosome binary markers improve phylogenetic resolution within haplogroup R1a1

Haplogroup R1a1-M198 is a major clade of Y chromosomal haplogroups which is distributed all across Eurasia. To this date, many efforts have been made to identify large SNP-based subgroups and migration patterns of this haplogroup. The origin and spread of R1a1 chromosomes in Eurasia has, however, remained unknown due to the lack of downstream SNPs within the R1a1 haplogroup. Since the discovery of R1a1-M458, this is the first scientific attempt to divide haplogroup R1a1-M198 into multiple SNP-based sub-haplogroups. We have genotyped 217 R1a1-M198 samples from seven different population groups at M458, as well as the Z280 and Z93 SNPs recently identified from the "1000 Genomes Project". The two additional binary markers present an effective tool because now more than 98% of the samples analyzed assign to one of the three sub-haplogroups. R1a1-M458 and R1a1-Z280 were typical for the Hungarian population groups, whereas R1a1-Z93 was typical for Malaysian Indians and the Hungarian Roma. Inner and Central Asia is an overlap zone for the R1a1-Z280 and R1a1-Z93 lineages. This pattern implies that an early differentiation zone of R1a1-M198 conceivably occurred somewhere within the Eurasian Steppes or the Middle East and Caucasus region as they lie between South Asia and Eastern Europe. The detection of the Z93 paternal genetic imprint in the Hungarian Roma gene pool is consistent with South Asian ancestry and amends the view that H1a-M82 is their only discernible paternal lineage of Indian heritage.

Spatial pattern analysis and competition between Acacia karroo trees in humid savannas

It is unclear whether inter-tree competition plays a role in determining the woody plant cover of humid savannas. Spatial point-pattern analysis can give insights to the underlying processes affecting the individuals in a population. We assessed the spatial patterns of Acacia karroo trees from savannas in KwaZulu-Natal, using conventional nearest neighbour analysis and second-order spatial statistics such as Ripley’s K- and L-functions, and the univariate and bivariate O-ring statistics. We predicted that juvenile trees would be spatially aggregated, because of facilitation between shrubs when zones of overlap are relatively small, while adult trees would be regularly spaced because of the effects of density-dependent mortality (i.e. consistent with the honeycomb rippling model). We found that juvenile trees were more aggregated than expected by chance, and the overall spatial distribution of all trees was also found to be aggregated, with no evidence of regularity among large individuals. Nearest neighbour analysis, however, revealed significant positive correlations between the sum of the distances to the four nearest neighbours and the sum of the canopy diameters of the target tree and its four nearest neighbours, indicating the presence of competition. In sum, these findings suggest that competitive interactions between A. karroo trees at these sites are relatively weak, and result in decreased performance (smaller canopy diameters) rather than mortality, thus preventing a regular pattern of tree distribution. We advocate the use of both methods of detecting competitive interactions in the field, especially if the effects of competition are too subtle to result in differential mortality.

The ATPase Pathway That Drives the Kinesin-14 Kar3Vik1 Powerstroke

Kar3, a Saccharomyces cerevisiae microtubule minus-end-directed kinesin-14, dimerizes with either Vik1 or Cik1. The C-terminal globular domain of Vik1 exhibits the structure of a kinesin motor domain and binds microtubules independently of Kar3 but lacks a nucleotide binding site. The only known function of Kar3Vik1 is to cross-link parallel microtubules at the spindle poles during mitosis. In contrast, Kar3Cik1 depolymerizes microtubules during mating but cross-links antiparallel microtubules in the spindle overlap zone during mitosis. A recent study showed that Kar3Vik1 binds across adjacent microtubule protofilaments and uses a minus-end-directed powerstroke to drive ATP-dependent motility. The presteady-state experiments presented here extend this study and establish an ATPase model for the powerstroke mechanism. The results incorporated into the model indicate that Kar3Vik1 collides with the microtubule at 2.4 μm(-1) s(-1) through Vik1, promoting microtubule binding by Kar3 followed by ADP release at 14 s(-1). The tight binding of Kar3 to the microtubule destabilizes the Vik1 interaction with the microtubule, positioning Kar3Vik1 for the start of the powerstroke. Rapid ATP binding to Kar3 is associated with rotation of the coiled-coil stalk, and the postpowerstroke ATP hydrolysis at 26 s(-1) is independent of Vik1, providing further evidence that Vik1 rotates with the coiled coil during the powerstroke. Detachment of Kar3Vik1 from the microtubule at 6 s(-1) completes the cycle and allows the motor to return to its initial conformation. The results also reveal key differences in the ATPase cycles of Kar3Vik1 and Kar3Cik1, supporting the fact that these two motors have distinctive biological functions.

Snellen versus logMAR visual acuity charts for evaluating driving standards in patients with neovascular macular degeneration

Purpose: To evaluate the use of Snellen and modified Early Treatment Diabetic Retinopathy Study (ETDRS) charts in estimating compliance with the UK Driver and Vehicle Licensing Agency visual acuity standard in patients with neovascular age-related macular degeneration. Methods: Patients with neovascular age-related macular degeneration in at least one eye underwent acuity test using 2m ETDRS chart, 6m Snellen chart and number plate test at 20m. The overlap zones between pass and fail in terms of ETDRS and Snellen charts were analyzed. The levels of descending acuity on the ETDRS chart that corresponded to varying percentages of patients passing or failing the number plate test were analyzed. Results: In total, 26 patients failed the number plate test and 24 patients passed. Fail acuities ranged from 6/36 to 6/6 on Snellen and from 49L to 79L on ETDRS chart. Pass acuities ranged from 6/12 to 6/5 on Snellen and from 67L to 85L on ETDRS chart. The overlap zone of acuities that contained patients who passed and failed was narrower with the ETDRS chart (69L–79L) compared to Snellen ( 6/6-6/12, which is equivalent to 85L-70L on ETDRS chart format). Conclusion: There are overlap zones of acuities in which patient’s presumptive eligibility to drive cannot be reliably estimated. An ETDRS cut-off of 77L provides a reasonable estimate of ability to pass the number plate test. These findings should provide a useful evidence base for advising patients of their compliance with the number plate test based on their logMAR acuity.

Partial closure of a crack-like cavity in an isotropic medium

On the basis of elasticity theory, a mathematical model is formulated for the closure of a crack-like cavity in an isotropic medium; the ends of the cavity are subject to the adhesive forces of the material. It is assumed that the interaction of the cavity surfaces under the action of bulk and surface loads may lead to zones of surface overlap. The unknowns that characterize cavity closure may be determined by the solution of a system of singular integrodifferential equations. The integral equations may be reduced to a system of nonlinear algebraic equations and solved by successive approximation. The contact stress, the forces between the edges of the cavity, and the dimensions of the end contact zones are determined.

이중 랜드마크 인식 기반 AGV 이동 제어

본 논문에서는 화장장이란 특수한 실내 공간에서 시신을 최종 목적지인 화장로까지 안전하게 운구할 수 있는 무인이송차량(AGV)의 이동 제어 문제를 다루고자 한다. 바닥에 유도라인을 매립하는 방식은 화장장 환경에 적합하지 않기 때문에, 적외선 센서 기반 AGV 이동 궤적 제어 방식을 제안한다. 이 방식은 AGV가 근적외선을 방사하여 미리 부착된 랜드마크(landmark) 판독을 통해 해당 경로를 따라 주행하게 된다. 이러한 방식이 갖는 문제점은 랜드마크 배열 과정에서 사각 지역(dead zone) 및 중첩 지역(overlap zone)이 존재할 수 있다는 점이다. 이를 해결하기 위해 이중 랜드마크 인식을 통해 센싱 과정에서의 오차 발생 과정을 최소화할 것이다. 또한, 화장로에 진입하기 위한 회전 구간에서는 회전 직후 화장로의 진입로와 일직선을 유지하도록 AGV 안쪽 바퀴와 바깥쪽 바퀴의 가속도 제어를 위한 알고리즘을 제안할 것이다. 본 논문에서 제안한 방식은 모의 차량에 적용하여 그 타당성을 검증하였다. 실제 국내 화장장에 본 논문에서 개발한 AGV 시스템을 적용하여 오차 범위 내에서 동작함을 확인하였다. In this paper the problem of a moving control of an automatic guided vehicle(AGV) which transports a dead body to a designated cinerator safely in a crematorium, an special indoor environment, will be discussed. Since a method of burying guided lines in the floor is not proper to such an environment, a method of moving control of an AGV based on infrared ray sensors is now proposed. With this approach, the AGV emits infrared ray to the landmarks adheres to the ceiling to find a moving direction and then moves that direction by recognizing them. One of the typical problems for this method is that dead zone and/or overlapping zone may exist when the landmarks are deployed. To resolve this problem, an algorithm of recognizing double landmarks at each time is applied to minimize occurrences of sensing error. In addition, at the turning area to entering the designated cinerator, to fit an AGV with the entrance of the designated cinerator, an algorithm of controlling the velocity of both the inner and outer wheel of it. The functional correctness of our proposed algorithm has been verified by using a prototype vehicle. Our real AGV system has been applied to a crematorium and it moves automatically within an allowable range of location error.

Is there a link between faulting and magmatism in the south-central Aegean Sea?

AbstractA distinct spatial relationship between surface faulting, magmatic intrusions and volcanic activity exists in the Aegean continental crust. In this paper, we provide detailed structural observations from key onshore areas, as well as compilations of lineament maps and earthquake locations with focal plane solutions from offshore areas to support such a relationship. Although pluton emplacement was associated with low-angle extensional detachments, the NNE- to NE-trending strike-slip faults also played an important role in localizing the Middle Miocene plutonism, providing ready pathways to deeper magma batches, and controlling the late-stage emplacement and deformation of granites in the upper crust. Additionally, the linear arrangements of volcanic centres, from the Quaternary volcanoes along the active South Aegean Volcanic Arc, are controlled primarily by NE-trending faults and secondarily by NW-trending faults. These volcanic features are located at several extensional settings, which are associated with the main NE-trending faults, such as (i) in the extensional steps or relay zones between strike-slip and oblique-normal fault segments, (ii) at the overlap zones between oblique-normal faults associated with an extensional strike-slip duplex and (iii) at the tip zone of a NE-trending divergent dextral strike-slip zone. The NE trend of volcano-tectonic features, such as volcanic cone alignments, concentration of eruptive centres, hydrothermal activity and fractures, indicates the significant role of tectonics in controlling fluid and magma pathways in the Aegean upper crust. Furthermore, microseismicity and focal mechanisms of earthquakes in the area confirm the activity and present kinematics of these NE- trending faults.