Hard Boundary Research Articles

Evaluation of Mechanism for EGR Deposit Formation Based on Spatially- and Time-Resolved Scanning-Electron-Microscope Observation

<div class="section abstract"><div class="htmlview paragraph">Exhaust gas recirculation (EGR) is widely used in diesel engines to reduce nitrogen oxide emissions. To meet the strict emission regulations, e.g., Real Driving Emissions, the EGR system is required to be used at temperatures lower than the present ones. However, under cool conditions, an adhesive deposit forms on the EGR valve or cooler because of the particulate matter and other components present in the diesel exhaust. This causes sticking of the EGR valve or degradation of the heat-exchange performance, which are serious problems. In this study, the EGR deposit formation mechanism was investigated based on spatially- and time-resolved scanning electron microscopy (SEM) observation. The deposit was formed in a custom-made sample line using real exhaust emitted from a diesel engine. The exhaust including soot was introduced into the sample line for 24 h (maximum duration), and the formed deposit was observed using SEM. The deposit was formed on the surface of the sample line below 300 °C (wall temperature) and had two layers: the deposit formed near the surface of the sample line had hard and dense structures, such as a lacquer (called a hard deposit), and the deposit formed on the hard deposit was powdery and exhibited a “grape-like” shape similar to particulate matter (called a powdery deposit). The amounts of both types of deposits increased in proportion to the duration of the exhaust supply. According to the SEM observations of the hard deposit, powdery deposit, and boundary layer between the positions where the hard and powdery deposits were formed, the hard deposit was formed by taking in the powdery deposit, when the exhaust including soot was supplied.</div></div>

Effects of the Top Edge Impedance on Sound Barrier Diffraction

Sound barriers can be configured with different top edge impedance to improve their noise control performance. In this paper, the integral equation method was used to calculate the sound field of a barrier with various top edge impedance, and the effects of the barrier top edge impedance on sound barrier diffraction were investigated. The simulation results showed that the noise reduction performance of a sound barrier with a soft boundary on its top edge was larger than that with a hard boundary, but there were some impedance values which, if assigned to the top edge boundary, would give the sound barrier even better noise reduction performance. It was found that the sound barrier with a good top edge impedance formed a dipole-like radiation pattern above the barrier to expand the effective range of the shadow zone. The research discoveries reported in this paper point out the potentials of using acoustics metamaterials or active control methods to implement the desired good impedance on the top edge of a sound barrier for better noise reduction.

Spatial aggregation and specificity of incidents with wildlife make tea plantations in southern India potential buffers with protected areas

Abstract: Many wildlife species survive in human-modified landscapes and understanding the opinions of those who share space with wildlife will aid conservation efforts. Using a questionnaire, we assessed the presence of 12 mammal species in 78 tea plantations in the Nilgiris, southern India. We obtained data on (i) plantation size, location, and elevation, (ii) species presence over a year, (iii) type and number of wildlife incidents caused, (iv) financial cost of wildlife damage, and (v) support for wildlife conservation. We used a generalized linear model to assess whether the distance to protected areas, elevation, and plantation size influenced species presence and the effect of these variables and wildlife incidents on support for conservation. Among all species reported, Bonnet Macaque, Wild Boar, and Porcupine were the most widespread, and the former two and the Gaur reportedly caused >50% of damages. Crop damage was the most frequent (74%, n = 244), whereas livestock predation, attacks on people, and infrastructure damage constituted <10% of incidents reported. The cost of wildlife damage was negligible for 72 estates and significant for six. The number of species increased with proximity to protected areas, with increasing elevation and plantation area. Plantation management (62%) supported wildlife conservation, and support increased with decreasing plantation size, increasing distance to protected areas, and with a higher number of species reported, but decreased with increasing incidents of wildlife damage. Mitigating impacts of a few widely distributed species that cause disproportionate damage and compensating those that incur disproportionately high costs could increase support for conservation. Education and awareness programs for the plantation community can further help increase support and participation in wildlife conservation activities. Plantations can thus serve as supplementary habitats for wildlife in regions where hard boundaries between protected areas and human settlements prevail.

Jeff Morris: Hearing Voices

Jeff Morris: Hearing Voices

A new iteration clustering method for rock discontinuity sets considering discontinuity trace lengths and orientations

Discontinuity clustering is an important and preliminary step in estimating discontinuity properties. To group discontinuities quickly and accurately, in this study, a new iteration clustering method (NICM) based on the data of discontinuity orientations and trace lengths is proposed, with its corresponding algorithm code developed in MATLAB. The method assumes that the trace lengths of the discontinuities obey a specific distribution, through a redistribution of the discontinuities whose membership degree values are unclear to adjust the probability density function of the trace lengths to make them more closely obey the specific distribution. The membership degree value calculation and cluster code determination are two main core modules of NICM. The characteristics of the method were analyzed with three types of numerical models in which the data are synthetic and the clustering results can be clearly grasped. In contrast, the NICM and fuzzy C-means method were applied to group the discontinuities of a rock slope at the Changhe Dam located in Sichuan Province, southwestern China, at the same time. The results clearly demonstrate that (a) a 10% enhancement in the precision can be expected by considering the distribution of the trace lengths; (b) the assumed specific distribution of the trace lengths does not have an obvious effect on the precision improvement; and (c) the problem of hard boundaries can be effectively alleviated by using the method.

Improvement of Neural-Network Classifiers Using Fuzzy Floating Centroids.

In this article, a fuzzy floating centroids method (FFCM) is proposed, which uses a fuzzy strategy and the concept of floating centroids to enhance the performance of the neural-network classifier. The decision boundaries in the traditional floating centroids neural-network (FCM) classifier are "hard." These hard boundaries force a point, such as noisy or boundary point, to be assigned to a class exclusively, thereby frequently resulting in misclassification and influencing the performance of optimization methods to train the neural network. A fuzzy strategy combined with floating centroids is introduced to produce "soft" boundaries to handle noisy and boundary points, which increases the chance of discovering the optimal neural network during optimization. In addition, the FFCM adopts a weighted target function to correct the preference to majority classes for imbalanced data. The performance of FFCM is compared with ten classification methods on 32 benchmark datasets by using indicators: average F -measure (Avg.FM) and generalization accuracy. Also, the proposed FFCM is applied to nondestructively estimate the strength grade of cement specimens based on microstructural images. In the experimental results, FFCM achieves the optimal generalization accuracy and Avg.FM on 17 datasets and 21 datasets, respectively; FFCM balances precision and recall better than its competitors for the estimation of cement strength grade.

Statistical reprogramming of macroscopic self-assembly with dynamic boundaries

Self-assembly is a ubiquitous process that can generate complex and functional structures via local interactions among a large set of simpler components. The ability to program the self-assembly pathway of component sets elucidates fundamental physics and enables alternative competitive fabrication technologies. Reprogrammability offers further opportunities for tuning structural and material properties but requires reversible selection from multistable self-assembling patterns, which remains a challenge. Here, we show statistical reprogramming of two-dimensional (2D), noncompact self-assembled structures by the dynamic confinement of orbitally shaken and magnetically repulsive millimeter-scale particles. Under a constant shaking regime, we control the rate of radius change of an assembly arena via moving hard boundaries and select among a finite set of self-assembled patterns repeatably and reversibly. By temporarily trapping particles in topologically identified stable states, we also demonstrate 2D reprogrammable stiffness and three-dimensional (3D) magnetic clutching of the self-assembled structures. Our reprogrammable system has prospective implications for the design of granular materials in a multitude of physical scales where out-of-equilibrium self-assembly can be realized with different numbers or types of particles. Our dynamic boundary regulation may also enable robust bottom-up control strategies for novel robotic assembly applications by designing more complex spatiotemporal interactions using mobile robots.

Theoretical Investigation of Spherical Aberration Coefficient Solenoid Magnetic Lens

In this study, a modulating model for solenoid magnetic field was presented. This model describes the on axis field through its hard edginess parameter as well as its axial half of half width at half peak field. The modulating model indicates to increasing the spherical aberration at the fields from real soft boundary to hard boundary modulating model. The investigation simply shows stay the peak field value constant at all order n, and the field sketch diverges to the hard boundary shape within high values of n > 60 and, as well the half of half width of field is (a) for all orders n < 6.

Building on the ruins of empire: the Uganda Railway and the LAPSSET corridor in Kenya

This article explores colonial (dis-)continuities between the planned Lamu Port–South Sudan–Ethiopia Transport (LAPSSET) development corridor and the Uganda Railway (UR). The historical approach to infrastructure studies highlights the effects of large-scale infrastructures beyond their immediate material impact, and reveals their potential power to structure mobilities, historicities and politics of scale. With reference to relational theories, it is argued that the two projects gain their respective significance not only through their ability to connect distant places, but also by blocking and severing other competing ways of being mobile. Particularly, both infrastructure projects create technologies enabling easier and faster flow of capital and commodities but limit previously prevalent mobilities practised by caravans and semi-nomadic people in the region. Both projects, furthermore, produce particular ways of remembering the past and anticipating the future. The article identifies a major discontinuity in the politics of scale they respectively imply: while the UR aimed at producing a clear scalar hierarchy between empire and colony, the LAPSSET alleges to dissolve hard boundaries between scalar instances. This article is based on qualitative data collected during fieldwork along the proposed route of the LAPSSET corridor, as well as archive work regarding the UR.

Agreement between Two Commonly Used Pulp Tests in Determining Pulp Vitality

Background: The pulp tissue is confined within hard tissue boundaries and cannot be examined directly for health evaluation. Hence, its assessment is usually based on sensibility tests. Accurate diagnosis of the pulpal status requires evaluation with combination of sensibility tests. The objective of this study was to assess the mutual agreement between the electric pulp test and cold test in determining pulp vitality. Methods: Total 106 patients, aged 18 to 30 years, attending the dental OPD of Operative Dentistry/Endodontics department; Dr. Ishrat-ul-Ibad Institute of Oral Health Sciences, Karachi were selected for the study. The cold and electric pulp tests were used to determine the presence or absence of tingling sensation. Teeth were marked as vital in presence and non-vital in absence of any tingling or painful response. Agreement between these two tests was calculated using SPSS-18. To calculate the mean and standard deviation, descriptive statistics were applied for quantitative variables. For qualitative variables, frequencies and percentages were calculated. Kappa statistics was applied for agreement between electric pulp and cold test. Results: The cold test showed that 70.8% of the teeth were vital and 29.2% were necrotic. The electrical pulp test showed that 74.5% were vital and 25.5% were necrotic. The outcome showed 83.0% agreement between the tests; with kappa value of 0.574 which provided sufficient agreement with p-value=0.000. Conclusion: There was a high agreement found between the cold test and electric pulp test. Assessment of pulp vitality would be more accurate when EPT and Endo frost are used in combination.

Hunting, husbandry, exchange and ritual: animal use and meaning at Moxviquil, Chiapas Mexico

This study investigates the animal use of the ancient inhabitants of Moxviquil, a small urban center in the Jovel Valley of highland Chiapas, Mexico, that was occupied during the Late Classic (AD 600-900) and Early Postclassic periods (AD 900-1250). Zooarchaeological remains were recovered from the monumental zone, from a neighboring hilltop residential group, and from the funerary cave located immediately below the residential group. Rather than a hard boundary between house and wilderness, sacred and profane, the distribution of different species and elements reflect the ways in which animals and animal products were interwoven through the fabric of cultural practice. Domestic spaces reflect the selective husbandry and hunting of animals for everyday living, compared to the high-status crafts and dedicatory contexts of royal residences, and the carefully constructed microcosm of ritual activities represented in the funerary cave. Following Rapoport (1982) and Barthes (2012), we use a framework of low-level, mid-level and high-level meanings to understand everyday hunting and domestication practice, status and exchange relationships, and medicinal and ceremonial uses. Considering the meanings of particular animal species can provide a holistic perspective on the cultural practices that shaped royal, residential and ritual spaces at Moxviquil, and provide a perspective on broader issues of agro-urbanism and resiliency in highland Maya polities.

Business model design spaces in socio-technical transitions: The case of electric driving in the Netherlands

Whereas research acknowledges the potential of business model innovation (BMI) to destabilize an existing regime, the impact of a socio-technical system in transition on BMI remains under-conceptualized. To advance work in this direction, this study expands the concept of a business model design space (BMDS), which describes the opportunities and constraints to design novel ways of creating and capturing value from niche technologies available at a given point in time in a transition. Illustrated with the case of electric vehicles in the Netherlands, we show how BMI are affected by and, in turn, affect this design space. We find that the policy and the science and technology dimensions of the socio-technical system form hard boundaries to the BMDS that niche actors cannot directly overcome via BMI. Yet, BMI can push the softer industry, market, and cultural boundaries of the BMDS by supporting niche expansion via coupling novel technologies to business models that (i) conform to the current regime, or that (ii) attempt to transform the regime. This paper offers an analytical framework that connects firm- and system-level to support the exploration of questions like how much novelty niche actors can introduce into a ST-system at specific points in a transition.

Robust Estimation of Vehicle Motion States Utilizing an Extended Set-Membership Filter

Reliable vehicle motion states are critical for the precise control performed by vehicle active safety systems. This paper investigates a robust estimation strategy for vehicle motion states by feat of the application of the extended set-membership filter (ESMF). In this strategy, a system noise source is only limited as unknown but bounded, rather than the Gaussian white noise claimed in the stochastic filtering algorithms, such as the unscented Kalman filter (UKF). Moreover, as one part of this strategy, a calculation scheme with simple structure is proposed to acquire the longitudinal and lateral tire forces with acceptable accuracy. Numerical tests are carried out to verify the performance of the proposed strategy. The results indicate that as compared with the UKF-based one, it not only has higher accuracy, but also can provide a 100% hard boundary which contains the real values of the vehicle states, including the vehicle’s longitudinal velocity, lateral velocity, and sideslip angle. Therefore, the ESMF-based strategy can proffer a more guaranteed estimation with robustness for practical vehicle active safety control.

Spatial and climatic variables independently drive elevational gradients in ant species richness in the Eastern Himalaya.

Elevational gradients are considered important for understanding causes behind gradients in species richness due to the large variation in climate and habitat within a small spatial extent. Geometric constraints are thought to interact with environmental variables and influence elevational patterns in species richness. However, the geographic setting of most mountain ranges, particularly continuity with low elevation areas may reduce the effect of geometric constraints at lower elevations. In the present study, we test the effects of climatic gradients and continuity with the low elevation plains of the eastern Himalayan mountain range on patterns of species richness. We studied species richness of ants (Hymenoptera: Formicidae) on an elevational gradient between 600m and 2400m in the Eastern Himalaya–part of Himalaya biodiversity hotspot. Ants were sampled in nine elevational bands of 200m with four transects in each band using pitfall and Winkler traps. We used regression models to identify the most important environmental variables that predict species richness and used constrained null models to test the effects of contiguity between the mountain range and plains. We find a monotonic decline in species richness of ants with elevation. Temperature was a more important predictor of species richness than habitat complexity. Geometric constraints model weighted by temperature with a soft lower boundary and hard upper boundary best explained the species richness pattern. This suggests that a combination of climate and geometric constraints drive the elevational species richness patterns of ants.

Knowledge and uncertainty in Lyme disease detection: an evidence-based activism research study in the UK

ABSTRACT There are increasing levels of concern about policy and practice related to Lyme disease testing and diagnosis in the UK. A complex debate has emerged, with patient groups challenging clinical and testing practices. This paper focuses on four dimensions of diagnostic testing: accuracy, types of test, clinical application and test interpretation, to illustrate the divergence amongst and between official and patient group views. We explore these issues via analysis of information from sources including patient organisations’ documents and statutory policy and professional publications, supplemented by data from an online questionnaire survey. Our analysis shows a lack of consistency in policy, consumerist strategies among patients, and official policy that inhibits illness identity and maintains hard boundaries between patients’ experience and public health practice. We suggest that medical policy and practice have become entrenched in defensive testing and clinical protocol. We note recently emerging trends in consultation and patient group involvement, illustrating more participative public health governance. As a joint patient organisation-academic project, we contribute to understanding of patient organisation activism in public health by demonstrating our own collaborative, reflective ‘evidence-based’ activist research. Notably, in doing so we deploy a variety of forms of knowledge and ‘evidence’ beyond the often-acknowledged ‘experiential’ and ‘embodied’ forms. On this basis, we recommend that shared-decision-making and ‘facilitational’ advocacy would improve patients’ empowerment and their experiences of testing and diagnosis. We argue that such reforms will enhance the perceived legitimacy of ‘chronic’ Lyme disease claims even under the prevailing conditions of scientific and medical uncertainty.

A Soft Decoding Algorithm with Hard Decision Boundary Factor for High-Order M-APSK Signal

High-order amplitude phase shift keying is adopted in the latest digital satellite broadcasting system, which presents new challenges to the design of a receiver demodulation scheme. This study focuses on the soft decision decoding algorithm. Traditionally, maximum likelihood soft decision based on log likelihood ratio estimation is often used as a decoding scheme. Accordingly, a soft decision algorithm based on hard decision boundary is designed and the corresponding soft decision estimation formula is derived. Numerical analytical results show that the proposed soft decision algorithm can improve the error performance of a system and substantially reduce the complexity of implementation.

Hard carbon coatings antifriction properties improvement by alloying

The efficiency of hard carbon coatings with different structure to improve the tribological performance of contacting surfaces of machine parts working in heavily loaded conditions has been analyzed. The possibility of increasing the antifriction and wear-resistant characteristics of these coatings by doping them with metals of the chromium subgroup of the Periodic table has been demonstrated. The possible mechanisms of hard carbon coatings dry and boundary friction tribological properties improvement by alloying have been considered. The possible role of alloying elements choice, structural and tribochemical factors has been discussed.

Memory, Migration, and Modern Fiction: An Introduction

This introduction situates refugee and migrant fiction within discourses of memory studies, transnational migration, and cosmopolitanism. It describes a reorientation to place and time in refugee and migrant fiction that is defined by the ambient rather than hard boundaries of time and space. Memory and migration are bound together in such a way that the new place may offer the migrant a less intransigent dislocation, a reduced sense of alienation. A cosmopolitan approach to the transmission of refugee memory is one way to remember the past: by putting it in the service of a better future.

Holding time influence on creep behavior of transient liquid phase bonded joints of Hastelloy X

Transient liquid phase (TLP) bonding using various holding times (5, 80, 320, and 640 min) was conducted on Hastelloy X using an Ni–Cr–B–Si–Fe filler metal at 1070 °C. High temperature stress rupture (creep) tests were performed on the TLP bonded joints at 816 °C under a stress of 110 MPa. The 320 min holding time sample had the highest rupture life (95.9 ks). The presence of uniformly distributed borides along the joint grain boundaries was determined to be the primary reason for improved creep properties. These particles were observed using electron backscattered diffraction (EBSD). The large values of creep strain observed in the 640 min holding time sample were due to a decrease in the number of grain boundary borides present in the joint area. An investigation on the creep fracture surfaces revealed a transition of the failure mechanism from transgranular to intergranular with increasing holding time. The fracture surface and elemental map were studied using electron probe microanalysis (EPMA); results showed that cracks initiated at the interface of eutectic components in samples with lower holding times (5 and 80 min), while the hard and brittle grain boundary borides available in the joint were the preferred sites for crack initiation in the 320 min sample.

Point-coupling Hamiltonian for frequency-independent linear optical devices

We present the point-coupling Hamiltonian as a model for frequency-independent linear optical devices acting on propagating optical modes described as a continua of harmonic oscillators. We formally integrate the Heisenberg equations of motion for this Hamiltonian, calculate its quantum scattering matrix, and show that an application of the quantum scattering matrix on an input state is equivalent to applying the inverse of classical scattering matrix on the annihilation operators describing the optical modes. We show how to construct the point-coupling Hamiltonian corresponding to a general linear optical device described by a classical scattering matrix, and provide examples of Hamiltonians for some commonly used linear optical devices. Finally, in order to demonstrate the practical utility of the point-coupling Hamiltonian, we use it to rigorously formulate a matrix-product-state based simulation for time-delayed feedback systems wherein the feedback is provided by a linear optical device described by a scattering matrix as opposed to a hard boundary condition (e.g. a mirror with less than unity reflectivity).