Visibility Criterion Research Articles

A Practicable Measurement Strategy for Compliance Checking Number Concentrations of Airborne Nano- and Microscale Fibers

Despite compelling reports on asbestos-like pathogenicity, regulatory bodies have been hesitant to implement fiber number-based exposure limits for biodurable nanoscale fibers. One reason has been the lack of a practicable strategy for assessing airborne fiber number concentrations. Here, a method is proposed, detailed and tested for compliance checking concentrations of airborne nano- and microscale fibers. It relies on Poisson statistical significance testing of the observed versus a predicted number of fibers on filters that have sampled a known volume of aerosol. The prediction is based on the exposure concentration to test. Analogous to the established counting rules for WHO-fibers, which use a phase contrast microscopy-related visibility criterion of 200 nm, the new method also introduces a cut-off diameter, now at 20 nm, which is motivated by toxicological findings on multi-walled carbon nanotubes. This cut-off already reduces the workload by a factor of 400 compared to that necessary for imaging, detecting and counting nanofibers down to 1 nm in diameter. Together with waiving any attempt to absolutely quantify fiber concentrations, a compliance check at the limit-of-detection results in an analytical workload that renders our new approach practicable. The proposed method was applied to compliance checking in 14 very different workplaces that handled or machined nanofiber-containing materials. It achieved detecting violations of the German benchmark exposure level of 10,000 nanofibers per cubic meter.

JEDDAH SCHOOL OF DESIGN

A School of Design is dedicated to the part of society who's interested in design as it will offer multiple field studies to be well-learned and practiced in its campus. The four major courses that this campus will offer are architecture, product design, fashion design, and graphic design. These four courses will be park under the roof of one building. Furthermore, as a design environment, it must have the basic facilities of studios, fabrication labs and computer labs as main functions of the building. Because it is an independent institute, it would also need some secondary needs such as a gallery and a library. The proposed space program of the project consists of admin and staff, learning facilities, educational services, display zone, student’s services and others. Site evaluation was conducted on the criteria of accessibility, views, visibility, surrounding, noise level, and infrastructure. The selected site for the project is at the intersection of the King Road and Abdulrahman Bin Alzubair Street. This project aims to create a space that suits the fields which will make studying less stressful and more enjoyable.

DI-CINEPLEX: ENTERTAINMENT AND CINEMA COMPLEX

Humans need entertainment to balance their stressful lifestyle. Normal life can be stressful, thus people need to relax to achieve a healthy lifestyle. Reducing stress with a good distraction such as entertainment or sports can drain the negative emotions. After some relax activities, humans will feel more relaxed and passive. This study aims to facilitate the balance lifestyle among the Arabian, thus proposed a project of entertainment and cinema complex in Beirut, Saudi Arabia. Several similar case studies were covered as the fundamental for the design idea. The space program of the project consists of twelve zones namely main entrance and reception halls, administration, maintenances, labour area, main cores and emergency exists, cinemas, facilities, warehouses, multi-storey parking, bike parking, outdoor stage and marina. The site located is selected based on the site evaluation criteria of accessibility, views, climatic, surrounding, visibility, supporting amenities, security, noise and distractions. The design concept of the complex is inspired by the concept of motion.

SURVIVORS UNION ADVENTURE WORLD

This study proposed a socio entertainment experiment simulated in a game that includes many different challenges that emphasis teamwork and on how to protect each other and surviving the situation. The formation of the design concepts and ideas are based on the chosen case studies such as the movie “The maze runner”, the resorts located at desert as well as the gaming world project. The project aims to integrate the game zone with others elements such as accommodation and training center. The space program of this study covered the public zone, restaurant zone, hotel zone, activities zone, outdoor activities zone, administration, and game zone. The chosen site is located at Thahban, Makkah Province Saudi Arabia based on the evaluation criteria of visibility, site size, site shape, access/ traffic, utilities, surrounding, views, demographic patterns, site attraction, topography, and expansion potential. The proposed project Survivors Union Adventure World provides an unforgettable and real challenge game experience for the player, also to build the relationship and bonding between each other.

A 3D meshfree crack propagation algorithm for the dynamic fracture in arbitrary curved shell

In this work, we proposed a meshfree crack propagation algorithm for dynamic fracture in arbitrary curved shell structures. In the numerical simulation of shell fracture, the treatment of crack discontinuity and simulation of fracture fragments are involved. In meshfree methods, since the connection between particles can be changed easily, which makes it suitable for dealing with such problems. In this study, firstly, the crack initiation algorithm for both ductile and brittle material is proposed based on the damage evolution. Besides, in the simulation, we assume that the crack tip coincides with the stress point, which means that the crack tip moves from one stress point to another, and by connecting the crack tip, the crack path is generated. Then a 3D visibility criterion for arbitrary curved shell structures is established, based on which the support domain of stress points is cut by the crack path to model the crack discontinuity. Finally, the crack propagation algorithm for dynamic fracture in curved shells is established; several numerical examples are studied to verify the reliability of the proposed algorithm.

PEMIKIRAN IMAM TAQI AL-DIN AL-SUBKI (683/1284-756/1355) BERKAITAN KRITERIA KENAMPAKAN ANAK BULAN: Imam Taqī al-Dīn al-Subkī (683/1284-756/1355) on Criteria for Lunar Crescent’s Visibility Issues

Taqī al-Dīn al-Subkī (d. 756/1355) has been unreservedly credited as one of the scholars in the fiqh and usul al-fiqh. His most important scholarly work Adillah fī Ithbāt al-Ahillah, clearly demonstrates his sholarship in the sciences of lunar crescent’s visibility. It will then explore how his positions corresponds or are relevant to lunar crescent visibility criteria issues in the contemporary ages. This article concludes that al-Subkī views on those isues are still relevant to the some current issues related to lunar crescent’s visibility criteria.

Дополненная реальность при визуализации данных с использованием свойств «золотого» сечения

Augmented reality, as a result of introducing into the field of perception data providing the best visualization of information, is increasingly attracting the attention of specialists in the field of software for demonstration complexes and geographic information systems. The visibility of the visualized information is important both for the work of the operator and users of the information system. Using the laws of visual perception of objects associated with the properties of the «golden» section, it is possible to formulate a visualization criterion for visualized data that characterizes the integrated perception of information displayed on the screen of a video monitor or projection panel. The purpose of the study presented in the article is to determine the visualization criterion for visualized data based on the properties of the «golden» section and study the conditions for its provision by the example of displaying of metadata on a monitor screen and projection panel. The visualization criterion is determined through the coverage coefficient of the screen area with information. The optimal value of the coefficient corresponds to the mathematical definition of the «golden» section. As a result of the study, it is necessary to highlight the analysis of the properties of the «golden» section when displaying information and the definition of the visualization criterion for data visualization, which allows operators and consumers to comprehensively perceive video data on electronic projection tools. Iterative algorithms have been developed for selecting the scale of data display by the criterion of visibility: an algorithm for analyzing the displayed layer data using an electronic map as an example and an algorithm for sequential layer analysis. The influence of the scale of the displayed data on the visibility of their visualization on screens of various sizes is investigated. The practical value of the results lies in the fact that the proposed criterion represents a mathematical interpretation of the property of the «golden» section for the visualization of information on modern electronic means of displaying data.

El coronel sí tiene quien le lea

Este artículo presenta los resultados de investigación a partir de la aproximación a dos proyectos innovadores en promoción de la lectura en el Caribe colombiano; La Carreta Literaria, en el departamento de Bolívar, y Biblioburro, en el departamento del Magdalena. Los objetivos de la investigación se direccionan a evaluar los efectos de la cooperación internacional en los proyectos a partir de la evaluación cualitativa de los criterios de visibilidad, cobertura, sostenibilidad y replicabilidad, realizando además un análisis crítico de las experiencias para establecer su relación con tres dimensiones de desarrollo; la inclusión y cohesión social, la participación ciudadana y la sostenibilidad cultural.
 Como técnica de investigación, se llevaron a cabo entrevistas semiestructuradas con diferentes grupos poblacionales siguiendo el método cualitativo de la sociología comprensiva. En general, los resultados de la investigación están encaminados a establecer los nexos entre prácticas de lectura y escritura, desarrollo humano y cooperación internacional.

Environmental aspects of ancient city planning: a pilot study on Ancient Thouria in the Peloponnese, Greece

ABSTRACT In this paper environmental, topographic and geological data of the Classical till Roman Times thriving city of Ancient Thouria situated in Messenia, SW Peloponnese, Greece are presented in context to their archaeological interpretation of the study area’s landscape and usage. Using environmental and geographic factors in collaboration with soil characterization, a preliminary spatial analysis was conducted, aiming at the archaeological interpretation of parameters such as water availability, weather conditions, topography, settlement accessibility and land fertility, taking under account analytical data of soil samples retrieved from a section of an ongoing excavation. The study was conducted using a digital elevation model of the area that enabled the examination of the criteria of watershed, slope, aspect and visibility and assisted X-ray Fluorescence analysis of soil samples from the Asklepieion excavated area thus highlighting the contribution of spatial and in situ analysis to archaeology.

An isogeometric-meshfree collocation approach for two-dimensional elastic fracture problems with contact loading

A strong form-based isogeometric-meshfree moving least-squares collocation (IMMLS-C) approach is developed for two-dimensional linear elastic fracture problems with contact loading. The IMMLS-C approach uses reproducing conditions to establish an equivalence between MLS shape functions and isogeometric basis functions. The advantages of this approach include the exact geometry representation, convenient crack modeling and flexible adaptive refinement. The IMMLS-C approach focuses on solving fracture problems based on strong formulations without requiring the numerical integration of Galerkin weak forms. Traction-free boundary conditions are enforced over a set of collocation points located on both sides of a crack surface. The displacement discontinuity along the crack surface is modeled by the visibility criterion and the singularity of near-tip stress fields is captured by adaptive mesh refinement without adding tip-enrichment functions, thereby reducing the degrees of freedom compared with the extended finite element method. Moreover, contact constraints are enforced by introducing a penalty algorithm to the strong formulations. The numerical results demonstrate that the adaptive refinement is able to achieve a high convergence rate at a low computational cost.

An h-adaptive meshfree-enriched finite element method based on convex approximations for the three-dimensional ductile crack propagation simulation

A new numerical approach for modeling the three-dimensional ductile crack propagation problem is presented. The approach is obtained by the introduction of an h-adaptive finite element refinement scheme using the element-wise meshfree enrichments and meshfree visibility criteria to achieve the desired accuracy due to the material nonlinearity and topological changes in the presence of displacement discontinuity. To ensure the element compatibility condition, meshfree convex approximations are employed to the finite element refinement scheme. A crack propagation algorithm combining the meshfree discretization and the crack surface tracking scheme is proposed. To further simplify the freeform surface generation in this moving discontinuity problem, a meshfree particle integration method is considered. Finally, two numerical benchmarks are studied to examine the effectiveness of present method in the three-dimensional ductile crack propagation analysis.

The new hilaal visibility criterion for tropical region

We propose a new Hilaal (lunar crescent formed immediately after conjunction) visibility criterion apply to tropical region utilizing modified mathematical model of near-sun objects visibility. By using only naked eye positive sightings of Hilaal, then we are calculating the Moon and Sun observation parameters to obtain the visibility function for each case. Moon – Sun altitude difference (ARCV – Arc of Vision) and elongation (ARCL – Arc of Light) at the first observable moment have been chosen as parameters and used in developing new visibility criterion. The data show that the minimum ARCV and ARCL value for naked eye observation at the moment of Hilaal is observed are 8.4° and 7.1°, respectively. Our results can be proposed as a scientifically criterion for constructing Hijri calendar for tropical region (including Indonesia) as an alternative to Jakarta Recommendations criterion.

Analisis Nuzul Al-Quran dengan Gerhana Matahari Cincin Perspektif Astronomi

Historians differ in their opinion regarding the time of Nuzūl al-Qur’ān i.e the 17th, 19th, 21st and 24th Ramadhan -12 H. The author is interested in verifying the time of Nuzūl al-Qur’ān by tracing the events that can be read easily the time and date i.e annular solar eclipse 27th January 632 AD when the death of Ibraham's son Muhammad. The author uses new moon data of Accurate Times 5.6 month data with crescent visibility criteria of Odeh and new MABIMS and by adding the 13th month (nasī') every 3 years to find out the date of the Nuzūl al-Qur’ān event. The purposes of this research are to know the date of Nuzūl al-Qur’ān by tracing annular solar eclipse 27th January 632 AD and to know the factors of the different date of Nuzūl al-Qur’ān among historians. This research uses historical research methods with steps: Heuristics (Source Collection), Source Criticism, Interpretation and Historiography (Presentation of results). The results of this research are Nuzūl al-Qur’ān occurred on Monday, 17 Ramadhan -12 H which coincided with 19 January 610 M

A robust meshfree method for analysis of cohesive crack propagation problems

In this paper, a new numerical approach is presented for the analysis of cohesive crack propagation in quasi-brittle materials. This approach effectively takes advantage of meshfree radial point interpolation method (RPIM) in conjunction with an accurate integration technique for simulation of cohesive crack growth. Using meshfree methods makes it possible to simply and efficiently model the propagation of the cohesive crack by adding a few number of nodes in the vicinity of the crack tip at each step of crack propagation. Furthermore, a discrete crack can easily be modeled in the meshfree formulation by methods such as visibility criterion. The meshfree method used here is based on the global weak formulation whose domain integrations are calculated with the background decomposition method (BDM). This integration technique can suitably evaluate the domain integrals with high accuracy and minimum computational cost. For the sake of modeling cohesive crack propagation path, consecutive straight segments are used, for each of which interfacial intervals are utilized to apply the constitutive law of cohesive zone. The discretized system of equations for the proposed meshfree method is derived and it is shown how the cohesive forces contribute in generation of the stiffness matrix. Through some numerical examples, the accuracy and efficiency of the proposed method for the analysis of cohesive crack propagation are verified. Also, the accuracy and efficiency of the proposed method are compared to other widely-used numerical schemes. By these examples, the superb efficiency of the presented technique is assessed. Particularly, it is shown that the number of nodes required for achieving accurate results is considerably smaller than other numerical methods such as the extended finite element method XFEM.

Stress resultant intensity factors evaluation of cracked folded structures by 6DOFs flat shell meshfree modeling

Several numerical examples for cracked folded structures are analyzed to investigate the mixed-mode stress resultant intensity factors (SRIFs). The kinematic formulations of structures are derived by the first order shear deformation plate theory. A Galerkin meshfree six degrees of freedom (6DOFs) flat shell is employed, in which the reproducing kernel (RK) is used as the meshfree interpolant. A diffraction method, visibility criterion and enriched basis are introduced to model the through crack. J-integral is evaluated based on the stress resultants and is decomposed into the symmetric and asymmetric parts for extracting the mixed-mode SRIFs. Not only the stiffness matrix but also the J-integral are discretized by nodes. They are numerically integrated by the stabilized conforming nodal integration (SCNI) and the sub-domain stabilized conforming integration (SSCI) techniques. The effectiveness of the meshfree modeling and accuracy in the SRIFs are discussed.

Vector visibility graph from multivariate time series: a new method for characterizing nonlinear dynamic behavior in two-phase flow

Visibility graph provides a well-tried and tested framework for graph-theoretical time series analysis. However, further research still needs to be conducted to extend visibility graph from univariate time series to multivariate time series. In this paper, we propose an algorithm to convert multivariate time series into a directed complex network termed vector visibility graph (VVG). The algorithm maps the multivariate time series to vector space and defines the visibility criteria between vectors. The constructed graphs inherit major property of the series in their topology demonstrated by the fact that random graphs are derived from multivariate random series, and scale-free networks are derived from multivariate fractal series. Finally, the VVG is employed to analyze the conductance sensor signals of typical flow patterns (bubble flow, slug flow, and churn flow) of gas–liquid two-phase flow. The average degree of vector visibility graphs can be utilized for flow pattern recognition. Moreover, the migration of the peak position of the degree distribution can effectively characterize the changes in fluid structure. The result indicates that VVG can effectively characterize nonlinear dynamic behavior in gas–liquid flow patterns.

Analytical field-of-regard representation for rapid and accurate prediction of agile satellite imaging opportunities

Agile Earth observation satellites (AEOSs) possess high-attitude maneuverability and achieve better efficiency than traditional platforms in imaging missions. Onboard mission scheduling of agile satellites requires rapid and accurate prediction of imaging opportunities. This problem has not yet been fully investigated in the previous literature. Our study presents a precise analytical model for field-of-regard (FoR) representation of agile satellites and applies a self-adaptive Hermite interpolation technique for rapid determination of imaging opportunities. The FoR of an agile satellite is regarded as a large virtual field-of-view (FoV) synthesized from infinite instantaneous FoVs of onboard camera corresponding to all possible orientations of agile satellite within limits of maximum maneuverability. Analytical equations of the bounding envelope of the FoR are formulated through quadratic curve fitting. Visibility criteria of the analytical FoR model are derived and piecewise cubic polynomials featured with autonomous searching for interpolation points are used to approximate the visibility functions. Numerical simulations show that the analytical FoR model approximates the truth model with an accuracy of better than 99%. In addition, the self-adaptive algorithm significantly reduces the computational cost for imaging opportunity determination compared to traditional trajectory checking method.

A Total Lagrangian SPH method for modelling damage and failure in solids

An algorithm is proposed to model crack initiation and propagation within the Total Lagrangian Smoothed Particle Hydrodynamics (TLSPH) framework. TLSPH avoids the tensile instability encountered in conventional Eulerian kernel-based Smoothed Particle Hydrodynamics (SPH) by making use of the Lagrangian kernel. In the present approach, the support domain of a particle is modified, where it only interacts with its immediately neighbouring particles. The gradient correction is employed to avoid the inconsistency of SPH approximation induced by insufficient neighbouring particles. A virtual link is used to define the level of interaction between each particle pair. The state of the virtual link is determined by damage law or cracking criterion. The virtual link approach allows easy and natural modelling of cracking surfaces without explicit cracking treatments such as particle splitting, field enrichment or visibility criterion. The performance of the proposed approach is demonstrated via a few numerical examples of both brittle and ductile failure under impact loading.

Visible Humanity

The objective of this work is to utilize Visible Human Project type imaging on a donated human cadaver specimen and integrate that image data and resultant anatomical modeling with the medical history and life experience of the donor for the education of medical and healthcare students. The Visible Human Project (1991) was focused on producing three‐dimensional, photographic image data of optimal human anatomy. Criteria for Visible Human specimens required a young donated cadaver with no visible pathology and no surgical interventions. In 2000, a woman presented with a passionate desire to be a “visible human”. It was eventually agreed (after she examined the freezer and cryomacrotome that would be used to section her) that her wish would be granted if the conditions of her death made it possible and if she would also include her medical and life history including video documentation of her remaining life as part of her donation. Motivation for her body and life history donation was to increase compassion among healthcare workers. In contrast to Visible Human Project criteria, she was 72 years old in 2000, had 26 surgeries including four cervical screws with connecting wires to stabilize her cervical vertebrae and a prosthetic hip. She survived melanoma, breast cancer and severe depression. She was sure and determined she would die within a year. She passed away on February 16, 2015. She was imaged with CT and MR and frozen. A plastic copy of her hip prosthesis was 3D printed from the CT data. The hip region was thawed and the prosthetic hip replaced with the plastic copy to permit sectioning the pelvis. The cervical screws and wires were not removed and were successfully sectioned. The cadaver was blocked into four subunits, each less than 20” in height in a manner similar to the Visible Human. Each block was embedded in polyvinyl alcohol dyed blue. Photographic images with 7,360 × 4,912 pixels (pixel size = 63 microns) were acquired in Nikon raw image format. Data includes over 20,000 transverse cross‐sectional photographs, CT and MR images, medical records and hours of recorded video of her life from 2002 till her death. She was introduced to participants at the Fourth Visible Human Conference in Keystone Colorado, October 17–19, 2002. At that conference, some participants participated in videotaped interviews with the donor.Segmentation of the photographic images has begun and 3D models of her aged vasculature reveal their tortuosity and pathology. 4K and HD videos of the cross‐sectional photographs have been rendered and will be available for viewing. CT renderings of the whole body and the cervical vertebral fusion will also be presented. This is NOT part of the Visible Human Project and that was made clear to the donor prior to herSupport or Funding InformationFunding provided by Touch of Life Technologies, Inc. and the University of Colorado Department of Cell and Developmental Biology.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Transient polarized radiative transfer in cloud layers: numerical simulation of imaging lidar returns.

In this paper, we investigate the time-dependent backscattering halo of a pulsed light beam in a layer of scattering medium. We start from numerical simulations of polarized radiative transfer in the layer, which immediately reveals the effect under investigation. Then we analyze time-dependent structure of the light field using the simulation results. From the radiation field, we extract two principal components, immediately forming the halo structure. For each diffuse and ballistic component, we use the proper theoretical model, yielding a convenient analytic description of the time-dependent behavior of the radiation field. From the theory developed by us, we derive a simple numerical criterion of visibility of the halo. Finally, we validate our theory against Monte Carlo radiative transfer simulations. Thus, we propose a quantitative explanation of the studied effect.