Shape Of Fragments Research Articles

Experimental Research on the Energy Evolution of Concrete under Impact Loading.

This paper presents an experimental study on the dynamic strength of concrete by using a split Hopkinson pressure bar. The stress-strain relationship and fragmentation degree of concrete were analyzed. The change process of the incident energy, reflection energy, transmission energy and consumption energy of concrete was calculated. The corresponding relationship between the variation of each energy and the stress state of concrete was studied. The law of energy evolution during the concrete fracture process was determined and the mechanism of concrete dynamic strength increase was revealed from the perspective of energy. The results show that the higher the strain rate, the higher the fragmentation degree of concrete, the smaller the grain diameter of fragments, the easier cracks are to pass directly through the aggregate, and the more regular the fragment shape. The change process of increasing amplitude of concrete consumption energy can reflect four mechanical states of concrete: stress increase, stress slow releasing, stress rapid releasing, and return-to-zero stress. Since the increase in reflected energy does not increase immediately with the increase in strain rate, it leads to the hysteresis of energy release in concrete, resulting in an increase in the dynamic strength of concrete.

Active laminated-plate model for spontaneous bending of Hydra tissue fragments driven by supracellular actomyosin bundles

The outstanding regeneration of Hydra’s excised tissue fragments occurs via initial spontaneous bending to some quasi-stable shape in several minutes. However, the underlying mechanism and dynamics of such initial spontaneous bending are still debated. Here, we propose that the spontaneous bending is driven mechanically by supracellular actomyosin bundles inherited from parent Hydra. Our active laminated-plate (ALP) model predicts that the equilibrium fragment shape is determined by anisotropy in contractility and elasticity. We construct a minimal dynamic ALP model including three dissipation mechanisms. By variational analysis and bead-spring simulations, we find that the bending process starts diffusively from the edges and relaxes exponentially to the equilibrium shape. The different dissipation mechanisms take place at distinct timescales: the viscous drag occurs in 0.001 seconds, while the interlayer frictional sliding and cellular dissipation take place in minutes. The ALP model could be adapted to study multi-layered viscoelastic tissues with nematic cytoskeletal structures and provides a useful framework for tissue morphogenesis and regeneration.

Responses of the Siberian crane population to temporal and spatial hydrological variations in stopover sites in northeast China

The Siberian crane (Grus leucogeranus), a critically endangered species, is used as an indicator species for ecosystem stability because of its sensitivity to the environment. The distribution of Siberian cranes has shown dramatic fluctuations on an order of magnitude at the main stopover site (Jilin Momoge National Nature Reserve) since the present century, which poses a great challenge to the conservation of endangered species. Research on the threshold values of key factors of the Siberian crane in stopover habitats and the relationship between the Siberian crane and hydrological temporal and spatial fluctuations can promote endangered species conservation. The response of population changes and distribution patterns of Siberian cranes to hydrological temporal and spatial patterns of wetlands was analyzed from 1984 to 2020. The results showed that population changes and distribution patterns of Siberian cranes were highly correlated with hydrological temporal and spatial patterns in the study area, and their variation trend was the same. However, there were obvious stage migration changes in the core activity area of the Siberian crane (1984–2000, 2001–2010 and 2010–2020). The habitat characteristics of fragmentation, dispersion and complex shape of water bodies changed from steady to dramatic fluctuations and then leveled off in the core activity area of Siberian cranes during the 37 years of migration transit. This was closely related to the early agricultural reclamation and the later ecological water replenishment project in the study area. In addition, the trend of the water pattern index of the spatial distribution of Siberian crane active habitat was also closely related to their habitat selection preference. When the perimeter area fractal dimension of water (1.27–1.40), landscape division index (0.73–0.95) and aggregation index (80.97–91.36) are within a certain stable threshold, the stopover habitat of the Siberian crane is suitable. This study will provide scientific guidance for the conservation of the Siberian crane population and the development of wetland restoration projects.

Impact of Rock Fragment Shapes and Soil Cohesion on Runoff Generation and Sediment Yield of Steep Cut Slopes under Heavy Rainfall Conditions

The erodibility and erosion resistance of Quaternary sediments play a pivotal role in both the hydrologic and erosion processes of soil cut slopes. To investigate the runoff and sediment yield of soil cut slopes along the Pai-Mo road, we performed indoor simulated rainfall experiments under a 50° steep slope and high rainfall intensity (120 mm/h), based on the area’s climatic characteristics and Quaternary sediment properties. The experiments included various rock fragment contents (30%, 40%, and 50%), different levels of rock fragment roundness (i.e., rounded gravel, angular gravel), and varying soil cohesion. The results indicated that the average infiltration rate of the uncemented rounded gravel soil slope (URGSS) was higher than that of the uncemented angular gravel soil slope (UAGSS), resulting in less runoff and a delayed initial runoff time. The runoff shear stress, runoff power, drag coefficient, and Reynolds number of the URGSS were smaller than those of the UAGSS. In contrast, the Froude number and flow velocity of the URGSS were larger, resulting in a stronger runoff erosion capacity. The sediment yield of the URGSS was approximately two times that of the UAGSS, and the cumulative sediment yield was about 20% higher. The cemented angular gravel soil slope (CAGSS) had a larger runoff rate, runoff shear stress, runoff power, and flow velocity than those of the UAGSS, leading to less sediment yield. Overall, a more rounded shape and a larger radius of curvature of the spherical particles resulted in stronger erosion, due to local turbulence. Therefore, the rill density and cumulative sediment yield of the steep alluvial cut slope were greater than that of the steep colluvial cut slope under heavy rainfall. Moreover, due to its strong cohesion, only raindrop splash erosion and inter-rill erosion occurred on the steep moraine cut slopes under heavy rainfall.

Analysis of the fractional composition of the dust of the working area when drilling composite materials based on carbon fibers

Modern production of unmanned aerial vehicles is characterized by the use of high-tech materials based on carbon fibers, the assembly operations of which are characterized by a large number of mechanical drilling operations, which are performed mainly by hand using a carbide tool with a diamond coating. The paper presents a study of the concentrations and dispersion of the dust composition and the geometric shape of the dust-forming particles in the working space of workers of machining shops during the technological operations of drilling, milling and countersinking of packages of composite materials based on carbon polyacrylonitrile fibers. On the basis of the conducted experiments, the regularities of the distribution of dust of different fractions in the horizontal and vertical planes of the working space at a distance covering the zone of the immediate location of the worker during this type of operation were determined. The obtained data made it possible to record a significant excess of the maximum allowable concentrations of finely dispersed residues of polyacrylonitrile fibers in the working area of the drill, 2.5 and 10 μm in size and elements of the carbon matrix. In order to investigate the possibility of a negative impact of the dust of the working area on the body of the worker, a study of the fractionation and geometric shape of carbon fiber fragments was performed using raster microscopy, based on which it was concluded that the fiber fragments have a spear-shaped, pointed shape, and the carbon matrix forms conglomerates, which are characterized sharp edges and can cause significant damage when they affect the human respiratory system. On the basis of the obtained results, recommendations were given in the work to improve the indicators of the dust load of workers to normalized values with the help of the use of special suction devices and personal protective equipment with special filters.

Effect of agricultural microplastic and mesoplastic in the vermicomposting process: Response of Eisenia fetida and quality of the vermicomposts obtained

This work evaluates the effect of agricultural plastic waste (APW) in two particle sizes, microplastic and film debris, and subjected to a pre-treatment by exposure to UV-C, in the development of the vermicomposting process. Eisenia fetida health status and metabolic response and the vermicompost quality and enzymatic activity were determined. The environmental significant of this study is mainly related to how can affect plastic presence (depending on plastic type, size and/or if it is partially degraded) not only to this biological process of organic waste degradation, but also to the vermicompost characteristics, since these organic materials will be reintroduced in the environment as organic amendments and/or fertilizers in agriculture. The plastic presence induced a significant negative effect in survival and body weight of E. fetida with an average decrease of 10% and 15%, respectively, and differences on the characteristics of the vermicomposts obtained, mainly related with NPK content. Although the plastic proportion tested (1.25% f. w.) did not induce acute toxicity in worms, effects of oxidative stress were found. Thus, the exposure of E. fetida to AWP with smaller size or pre-treated with UV seemed to induce a biochemical response, but the mechanism of oxidative stress response did not seem to be dependent on the size or shape of plastic fragments or pre-treated plastic.

Forest fragmentation and its associated edge-effects reduce tree species diversity, size, and structural diversity in Madagascar’s transitional forests

AbstractTropical forests are being cleared at an accelerating rate, despite being one of the most important habitats for global biodiversity. Many remaining tropical forest tracts are now highly degraded and fragmented, which presents a major problem for sensitive and threatened forest-dwelling species that depend on this habitat for survival. In this study, we assessed the impacts of forest fragmentation, and its associated edge-effects, on tree species diversity, tree size, and structural diversity within the transitional forests of north west Madagascar. Using data collected from 9,619 trees within 200 vegetation plots, we calculated species diversity indices, a range of dendrometry measurements, and Shannon-Weaver diversity indices of structure, which we compared among core and edge areas of a continuous forest and a fragmented forest. We found that species diversity, tree size, and structural diversity was significantly reduced in fragmented forest, and within forest edge areas in comparison to core, continuous forest. We also observed species diversity and structural diversity to be strongly influenced by the total size, core area size, and shape of forest fragments. Whilst we found fragmentation and edge-effects to individually impact tree species diversity, size and structural diversity, fragmentation and edge-effects are strongly correlated and affect natural forest synergistically. Our results provide evidence that forest fragmentation seriously degrades habitat quality and integrity of transitional forests, which is of great concern for the threatened species that inhabit them. Urgent conservation efforts are needed to halt ongoing forest fragmentation throughout the tropics, and reforestation and restoration efforts are required to reconnect isolated forest patches and to reduce forest edge area.

Assessment of Small-Scale Microplastics Abundance and Characterization in Urban River: A Case Study in Metro River, Indonesia

Microplastic pollution is a pressing environmental concern with detrimental effects on aquatic ecosystems and human health. This study aimed to investigate microplastic contamination in a rapidly urbanizing area along a river and to examine the spatial distribution of microplastic abundance across the study area based on land use type. Seven sampling points were selected along the study site and microplastic samples were extracted using density separation and wet peroxidation (WPO) methods. The characteristics of the microplastic particles, including size, color, shape, and abundance, were analyzed to understand their properties. The results indicated that the microplastic abundance values ranged from 28.33 to 133.00 particles/liter, with an average of 73.55 particles/liter. Small microplastic particles (SMP), with sizes ranging from 1 μm to 1 mm, along with fragment shapes, and clear colors were predominant in the study area. A generalized additive model was utilized to assess the relationship between land use and microplastic abundance. The model demonstrated a significant influence of built-up areas on the presence of microplastics (p-value < 0.05), with an r2 value of 0.76. Residential areas near the river were identified as the likely primary sources of the microplastics.

Updates on the DebriSat hypervelocity experiment and characterization of fragments in support of environmental models

To develop, maintain, and update orbital debris environmental and break-up models, such as the NASA Orbital Debris Engineering Model (ORDEM) and the NASA Standard Satellite Breakup Model (SSBM), the NASA Orbital Debris Program Office (ODPO) relies on the most recent validated datasets from various measurement sources, both laboratory and environmental. One key project that will provide insight for break-up events using modern-day spacecraft materials and construction techniques is the DebriSat laboratory hypervelocity-impact test. Based on the mass of the target, the projectile, and the impact velocity, the expected number of fragments greater than 2 mm, generated using the NASA SSBM, was estimated to be close to 85,000. To date, the DebriSat fragment database continues to grow, with over 200,000 fragments collected that will help inform updates to the SSBM. Additionally, the growing fragment ensemble will support key parameters for the next release of NASA's environmental models, employing fragment shapes, densities, and size distributions. To further support these environmental models, specifically the size parameter used in ground-based optical measurements, optical characterization on a subset of DebriSat fragments is being conducted in ODPO's Optical Measurement Center (OMC). Broadband bidirectional reflectance distribution (BRDF) measurements will provide insight into the optical-based NASA Size Estimation Model (OSEM). The OSEM equates an object's brightness to size (e.g., diameter of a disk or sphere) given several assumed parameters, including a defined phase function, albedo, and range. To address the first defined parameter, the ODPO has been using ray-tracing software to simulate light conditions in the OMC and to generate phase functions (i.e., specular, Lambertian, and experimentally derived) of known shapes, materials, and sizes. This simulated data, in addition to the experimentally derived measurements collected in the OMC, will aid in determining whether a new phase function would be suitable for an updated OSEM. The OSEM also assumes a single-value albedo, thus pre-impact spectral measurements on a subset of DebriSat materials were acquired for baseline material characterization and to provide insight into spacecraft material taxonomies. This DebriSat spectral data, along with spectral measurements from other known spacecraft material samples, will allow for better analyses of albedo variations and the effect on size calculations of defined laboratory targets, thus further supporting OSEM updates. This paper provides an overview of DebriSat, the status of the project, updates on the parameter distributions, an overview of the NASA SSBM, and ongoing fragment characterization efforts within the OMC.

Microplastic pollution in table salt and sugar: Occurrence, qualification and quantification and risk assessment

Microplastics (MPs) have recently been observed in many products and environmental samples, ranging from drinking water to food products. In this study, the contamination of several popular brands of Iranian table salts and sugars by MPs was investigated. By using an optical and staining stereomicroscopic method the samples were counted. Results showed MPs were detected in all samples of salts and sugars. The average amounts of MPs in different brands of salt and sugar observed were 55.2 ± 43.7 MP/kg and 57.7 ± 20.6 particles/kg, respectively. Based on Nile red staining the average microplastics in salts and sugars were 151.3 ± 61.8 and 226 ± 99.5 particles/kg. Most MPs were present in the shape of fragments (78.57 % and 95.8 %), while only a few were in the fiber shape (21.43 % and 4.1 %) in salts and sugars, respectively. The qualifying of plastic particles was conducted with Fourier-transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM). Polyethylene (PE) and polypropylene (PP) were identified as the most likely polymers. The maximum annual exposure of MPs was approximately 15,540 and 23,660 particles/kg/bw/year for adults and 3552 and 5408 particles/kg/bw/year for children through salts and sugars, respectively. Based on these findings, it can be concluded that MPs can enter the food chain through additives (such as heavy metals, toxic organic matter and pathogens), and can affect human health.

Different driving mechanisms of spatial heterogeneity at the community and landscape levels in the wetland ecosystem dominated by hydro‐ecological processes

AbstractThe analysis of wetland patterns and their driving mechanisms is the research focus of discussion in wetland ecology. In this study, we tried to analyse the spatial differentiation patterns of community and landscape levels dominated by hydro‐ecological processes. The spatial differentiation patterns of landscape patterns and their driving mechanisms were explored in focus. This study was based on 30‐year land cover data of Baiyangdian Wetland Nature Reserve in North China Plain, China, constructing an ecological response relationship matrix between inundation frequency and vegetation cover frequency for the spatial divide at the community and landscape level. By constructing a landscape index set and analysing the index set using clustering, non‐metric multidimensional scale analysis, discriminant and redundancy analysis, we finally obtained the differentiation characteristics of wetland landscape patterns and their driving mechanisms. The spatial differentiation of community levels along the water level gradient showed a banded distribution pattern of submerged‐floating‐emerge to meadow shrubs, but the stability of the hydrological regime dominated the spatial differentiation of landscape levels. Wetland landscapes along the stability gradient of the hydrological regime were divided into stable and fluctuating zones. The stable zone had the landscape pattern characteristics of low fragmentation, simple and regular shape and high numbers of different patch types; the landscape pattern of the fluctuating zone was characterized by a high fragmentation and complex shape, with a small number of different patch types and a non‐uniform distribution. The analysis of the driving mechanism showed that the stability of the hydrological regime was the only reason for the formation of the landscape pattern of the stable zone. The combined effect of human‐dominated and natural‐supplemented effects jointly drove the formation of the landscape pattern of the fluctuating zone. The influence of human on the landscape pattern of the fluctuating zone showed a trend of spatial expansion from high areas to shallow water areas. The combination of traditional landscape indices and aquatic ecological processes characterized the spatial differentiation of wetland landscape patterns, and also verified the feasibility of this method. This study was a successful example of conducting ecological process‐oriented landscape level spatial differentiation analysis. The results of the study are intended to provide recommendations for the rational and effective use and precise conservation of wetland plant and animal resources and the restoration of wetland ecosystems.

Pre-control of shell expansion fracture process by high energy beam

Aiming at the dynamic deformation and fracture response of high-energy precontrolled shell under high strain rate,the expansion and fracture process of 40CrMnSiB steel precontrolled shell was studied by numerical modeling and experiment.The results show that:In detonation loading condition,the high energy beam precontrol shell expansion fracture process can be divided into three stages of free expansion,precontrol fracture and matrix fracture.Firstly, the brittle fracture occurs in the fusion region, and the crack starts at the bottom of the cavity region and propagates along the fusion region to the outer wall of the shell. After the brittle fracture is completed, the adiabatic shear fracture occurs in the matrix, and the normal line between the fracture surface and the inner wall of the fragment is 45 °.The recovered fragment shape is in the shape of precontrolled quadpyramid,and the fragment quality is concentrated in the precontrol area. the fragment dispersion has a good distribution law,which better verifies the pre-control effect of high-energy beam pre-control technology on the fragment shape and the direction of dispersion,and provides technical reference for further optimization of high-energy beam pre-control warhead structure.

High‐throughput genotyping in estimating genetic resources and detecting pathogens in aquaculture

High‐throughput genotyping in estimating genetic resources and detecting pathogens in aquaculture

Study the Influence of Fragment Shape on Penetration Failure Process of Thin Target Plate

In order to study the influence of fragment shape on the process of penetrating the target plate, the spherical and cubic structural steel fragments of the same mass which penetrating aluminum target plate has been studied by theoretical and numerical simulation calculations. The theoretical calculation shows that the ballistic limit velocity of the fragments of the cube structure is higher than that of the spherical structure when the fragments of the same mass penetrate the target plate of the same thickness. Numerical simulations have obtained the penetration process and failure rule of the fragment to the target plate. The results show that the target plate failure during the penetration process of the spherical fragment is a tensile failure mode, however, the penetration process of the cube structure fragment are shear and tensile mixed failure modes.

Anaphylatoxin C5a receptor signaling induces mitochondrial fusion and sensitizes retinal pigment epithelial cells to oxidative stress

Mitochondrial dynamics is a morphological balance between fragmented and elongated shapes, reflecting mitochondrial metabolic status, cellular damage, and mitochondrial dysfunction. The anaphylatoxin C5a derived from complement component 5 cleavage, enhances cellular responses involved in pathological stimulation, innate immune responses, and host defense. However, the specific response of C5a and its receptor, C5a receptor (C5aR), in mitochondria is unclear. Here, we tested whether the C5a/C5aR signaling axis affects mitochondrial morphology in human-derived retinal pigment epithelial cell monolayers (ARPE-19). C5aR activation with the C5a polypeptide induced mitochondrial elongation. In contrast, oxidatively stressed cells (H2O2) responded to C5a with an enhancement of mitochondrial fragmentation and an increase in the number of pyknotic nuclei. C5a/C5aR signaling increased the expression of mitochondrial fusion-related protein, mitofusin-1 (MFN1) and − 2 (MFN2), as well as enhanced optic atrophy-1 (Opa1) cleavage, which are required for mitochondrial fusion events, whereas the mitochondrial fission protein, dynamin-related protein-1 (Drp1), and mitogen-activated protein kinase (MAPK)-dependent extracellular signal-regulated protein kinase (Erk1/2) phosphorylation were not affected. Moreover, C5aR activation increased the frequency of endoplasmic reticulum (ER)-mitochondria contacts. Finally, oxidative stress induced in a single cell within an RPE monolayer (488 nm blue laser spot stimulation) induced a bystander effect of mitochondrial fragmentation in adjacent surrounding cells only in C5a-treated monolayers. These results suggest that C5a/C5aR signaling produced an intermediate state, characterized by increased mitochondrial fusion and ER-mitochondrial contacts, that sensitizes cells to oxidative stress, leading to mitochondrial fragmentation and cell death.

Plastic wastes and surface antibiotic resistance genes pollution in mangrove environments.

Mangroves are located at the intersection of land and sea and are also heavily affected by plastic wastes. Biofilms of plastic wastes in mangroves are reservoirs for antibiotic resistance genes (ARGs). In this study, plastic wastes and ARG pollution were investigated from three typical mangrove areas in Zhanjiang, South China. Transparent was the dominant colors of plastic wastes in three mangroves. Fragment and film shape accounted for 57.73-88.23% of plastic waste samples in mangroves. In addition, 39.50% of plastic wastes in protected area mangroves are PS. The metagenomic results shows that the 175 ARGs were found on plastic wastes of the three mangroves, the abundance accounting for 91.11% of the total ARGs. The abundance of Vibrio accounted for 2.31% of the total bacteria genera in aquaculture pond area mangrove. Correlation analysis shows that a microbe can carry multiple ARGs that may improve resistance to antibiotics. Microbes are the potential hosts of most ARGs, suggesting that ARGs can be transmitted by microbes. Because the mangroves are closely related to human activities and the high abundance of ARGs on plastic increases the ecological risks, people should improve plastic waste management and prevent the spread of ARGs by reducing plastic pollution.

Pathoanatomy of pertrochanteric fractures - a postmortem study

BackgroundRecent pathoanatomic studies based on 3D CT reconstructions have questioned validity of AO/OTA classification because it does not reflect the reality and requires revision. These 3D CT studies, however, do not allow analysis of all details. Therefore, we have exploited the possibility to analyze the pathoanatomy of pertrochanteric fractures on postmortem specimens. Material and methodsFrom the collection of the Institute of Anatomy, the authors obtained 16 specimens of hip joints of individuals who had sustained a pertrochanteric fracture and died within 30 days of the injury, with anteroposterior radiographs of the injured hip available in all of them. The number of major fragments and their shape, and the courses of the main fracture lines were studied. ResultsThree major fragments (a proximal head and neck fragment, a distal diaphyseal fragment and a posterior flat fragment), separated by three types of fracture lines (primary, secondary and tertiary lines) were identified. The primary line separated the proximal fragment (head and neck) from the distal diaphyseal fragment. The secondary fracture line separated the posterior flat fragment from the distal diaphyseal fragment. The tertiary fracture line split the posterior fragment into two parts. A key factor for fracture instability is the defect of the posterior cortex, which depends on the size and shape of the posterior fragment. Avulsion of the lesser trochanter and the adjacent cortex results in an unstable configuration of fracture lines on the medial side, while on the lateral side a large posterior fragment weakens the lateral trochanteric wall. ConclusionIn agreement with recent CT studies, the findings of this pathoanatomical study change, in a number of aspects, the traditional view of the pathoanatomy and classification of pertrochanteric fractures, and introduces the concept of three, instead of the traditional four, main fragments.

Urban Journeys of the Rhizomatic Line

Using visual hierarchy, representational media often separate diverse urban experiences. Three categories of foreground, middle ground, and background are easily distinguished in photography and painting. Urban sketches separate buildings, figures, and natural features. In architectural working drawing, “poché, entourage, and mosaïque” forms a structural system for representing cut walls, environment, and texture respectively[1]. Recently, photogrammetry or Lidar scanning claim to break these hierarchies by creating “a uniform unbiased document of things in space as they exist.”[2] However, these tools fail to reveal the speculative imaginary experiences hidden behind surfaces.This series of my drawings that I named “rhizomatic line”, is the result of a non-hierarchical process inspired by French philosophers Gilles Deleuze and Felix Guattari's concept of rhizomes. Described as an array of attractions without beginning or end, a rhizome negotiates between things, “fosters connections between fields, the removal of blockages.”[3] Rather than producing fragmented abstract shapes, the rhizomatic line moves between the objects and intertwines them. Seemingly recording eye movement, rhizomatic, line does not construct complete outlines, but through loosing their completion, it connects them. As it explores the city, it does not differentiate between humans, pedestrian lines, high-rise building edges, urban skylines, stairways, leaves of a small plant hiding behind a window in a private room, entrances to residential units atop towers, or imaginative spaces.When looking at similar images, different people show different eye movements.[4] A designer sees the world in the process of construction, and from multiple perspectives at once. Architects use a specific language to draw rhizomatic lines. Axonometric projection takes advantage of both the visual aspect of perspective in photography, as well as the mathematical precision of orthographic projection in computer cartesian systems. Although I do not claim that my rhizomatic lines are true or close to the vision, I emphasize on " a continuous space in which elements are in constant motion."[5] The dotted texture suggests one understanding of the scene's porosity, among many others. Through the blurring of boundaries between poché, entourage, and mosaïque, only a portion of the image is displayed as a work under construction, inviting the viewer to complete it with their imagination. In this sense, a rhizomatic line is not a cartesian representation of space. This single “active line” ending in itself, is an exploratory journey fusing imaginations, speculations, desires, memories, and dreams about the city; “a walk for a walk's sake.”[6] [1] Michael Young, Reality Modeled After Images: Architecture and Aesthetics After the Digital Image. (New York: Routledge, 2021), 10. [2] Young, Reality Modeled After Images: Architecture and Aesthetics After the Digital Image. 53. [3] Gilles Deleuze and Felix Guattari, A Thousand Plateaus: Capitalism and Schizophrenia. Translated by Brian Massumi, (Minneapolis: University of Minnesota, 1987), 12. [4] Alfred Yarbus. "Eye Movements During Perception of Complex Objects." Eye Movements and Vision”, (Springer: Boston, MA, 1967) [5] Stan Allen. "Construction with Lines: On Projection", Practice: Architecture, Technique+ Representation. (New York: Routledge, 2009), 19. [6] Paul Klee. Pedagogical Sketchbook. Translated by Sybil Moholy-Nagy, (New York: Praeger Publisher,1953), 16.

Analysis of Fragment Distributions from Carbon-Fiber-Reinforced Composite Panels Subjected to Hypervelocity Impacts

In the last decades, carbon-fiber-reinforced composite plates (CFRPs) have been widely employed for various structural applications on board spacecraft. Compared to metals, CFRPs present different mechanical properties related to the anisotropy of the fibers; this can strongly influence the response of CFRPs to hypervelocity impacts. In this work, four impact experiments performed on thin panels of CFRPs are presented to assess the influence of the impact velocity and of the impactor size on the fragmentation process; experimental data include fragment cumulative size and shape distributions. It is shown that size distributions strongly differ from aluminum plates in terms of the total number and shape. Significant differences are also shown on the shape distributions, which are mostly related to the presence of needle-shaped fragments.

Criteria for the implementation of ecological corridors in fragmented areas in southern Brazil

The present study aims to analyze the potential of areas for the implementation of ecological corridors. The study area represents a transition between the Atlantic Forest and Cerrado domains and is extensively fragmented. Geographic Information System was used to determine suitable areas for the implementation of ecological corridors based on their ecological and structural potential, while multi-criteria classification was used to generate a final ecological map of the area. Weights and notes were assigned to vegetation class, river width, elevation and declivity in their respective maps, which were overlaid using ArcGis 10.3 software. Structural analysis of the area used the landscape metrics mean area, mean shape and total edge of fragments and mean connectivity among fragments in Fragstats software. The results indicated an ecologically and structurally suitable area for the implementation of ecological corridors in the study area.