Eighth Layer Research Articles

Dynamic design of hazardous chemical storage in high-rise R&D building based on numerical simulation

With the increasing demand for research on hazardous chemicals in high-rise research and development (R&D) buildings, the use of a large number of flammable chemicals increases the fire risk significantly. Therefore, the research on the storage of hazardous chemicals in high-rise R&D buildings becomes more and more important. This paper presents a maximum dynamic design method for hazardous chemical storage. A set of fire risk indicators has been established in the research, including temperature, carbon monoxide concentration, and visibility. The representative hazardous chemicals are selected through the investigation of the distribution and quantity of hazardous chemicals. Through numerical simulation of high-rise building fire with different stocks of dangerous chemicals and evacuation simulation of different fire floors, the time when the risk factors of fire occurrence reach the critical threshold of human body (ASET) and the necessary time for human evacuation (RSET) are obtained. By adjusting the amount of hazardous chemicals stored, the time to reach the hazardous critical threshold (RSET) and the time to evacuate (ASET) are changed accordingly. When RSET < ASET, the storage capacity of hazardous chemicals in the high-rise R&D building meets the target requirements. In the case study, ethanol was selected as the representative substance, and numerical simulation and example calculation were carried out on a 16-story R&D building. The amount of ethanol stored on each floor was calculated. Among them, the eighth layer has the largest ethanol storage capacity (1.81 L/m2) and the ninth layer has the smallest ethanol storage capacity (0.89 L/m2).

An Improved Rotating Box Detection Model for Litchi Detection in Natural Dense Orchards

Accurate litchi identification is of great significance for orchard yield estimations. Litchi in natural scenes have large differences in scale and are occluded by leaves, reducing the accuracy of litchi detection models. Adopting traditional horizontal bounding boxes will introduce a large amount of background and overlap with adjacent frames, resulting in a reduced litchi detection accuracy. Therefore, this study innovatively introduces the use of the rotation detection box model to explore its capabilities in scenarios with occlusion and small targets. First, a dataset on litchi rotation detection in natural scenes is constructed. Secondly, three improvement modules based on YOLOv8n are proposed: a transformer module is introduced after the C2f module of the eighth layer of the backbone network, an ECA attention module is added to the neck network to improve the feature extraction of the backbone network, and a 160 × 160 scale detection head is introduced to enhance small target detection. The test results show that, compared to the traditional YOLOv8n model, the proposed model improves the precision rate, the recall rate, and the mAP by 11.7%, 5.4%, and 7.3%, respectively. In addition, four state-of-the-art mainstream detection backbone networks, namely, MobileNetv3-small, MobileNetv3-large, ShuffleNetv2, and GhostNet, are studied for comparison with the performance of the proposed model. The model proposed in this article exhibits a better performance on the litchi dataset, with the precision, recall, and mAP reaching 84.6%, 68.6%, and 79.4%, respectively. This research can provide a reference for litchi yield estimations in complex orchard environments.

A Three-Dimensional Geological Model of the R’Mel Aquifer, Northwestern Morocco

One of the challenges of 3D geological modelling is the spatial representation of heterogeneous sedimentary rocks. The R’Mel coastal basin located in northwestern Morocco is a very suitable area for the modelling of sedimentary rock formations. This basin is part of the external Pre-Rif area and is composed of rocks of Miocene to Quaternary age (principally sand, marl, sandstone, silt, and alluvia). Due to the impact of climate change, any increase in the abstraction of groundwater can accentuate its vulnerability to marine water intrusion. Therefore, understanding of geometry of this aquifer is so important. To achieve this, a 3D geological model was developed to determine the different HydroGeological Units (HGUs) of the R’Mel aquifer. The processing and the construction of a GIS database including a detailed geological map, 125 boreholes, and 50 vertical electrical soundings (VESs), as well as the development of five geological cross-sections, helped build this model using 3D modelling software. The model provides a detailed visualization of the spatial distribution of the eight HGUs. HGUs 3 and 6 consist of marly-clayey lenses and five HGUs of Plio-Quaternary age are composed of: sand or/and sandstone (HGU 1), calcarenites and lumachelles (HGU 2), sandstone and/or shelly marine sand (HGU 4), gravel with a sandy-clayey matrix (HGU 5), and shelly sandstone and gravelly sand (HGU 7). The eighth layer (HGU 8) is composed of marls and clays of Miocene age. The generation of several geological sections from the model made it possible to identify anticlines, synclines and faults trending NNW–SSE and NNE–SSW. Theses, support the tectonics of the Gharb basin during the Mio-Plio-Quaternary. Finally, a conceptual model of the R’Mel aquifer was developed.

End-to-End Light License Plate Detection and Recognition Method Based on Deep Learning

In the field of intelligent robot and automatic drive, the task of license plate detection and recognition (LPDR) are undertaken by mobile edge computing (MEC) chips instead of large graphics processing unit (GPU) servers. For this kind of small computing capacity MEC chip, a light LPDR network with good performance in accuracy and speed is urgently needed. Contemporary deep learning (DL) LP recognition methods use two-step (i.e., detection network and recognition network) or three-step (i.e., detection network, character segmentation method, and recognition network) strategies, which will result in loading two networks on the MEC chip and inserting many complex steps. To overcome this problem, this study presents an end-to-end light LPDR network. Firstly, this network adopts the light VGG16 structure to reduce the number of feature maps and adds channel attention at the third, fifth, and eighth layers. It can reduce the number of model parameters without losing the accuracy of prediction. Secondly, the prediction of the LP rotated angle is added, which can improve the matching between the bounding box and the LP. Thirdly, the LP part of the feature map is cropped by the relative position of detection module, and the region-of-interest (ROI) pooling and fusion are performed. Seven classifiers are then used to identify the LP characters through the third step’s fusion feature. At last, experiments show that the accuracy of the proposed network reaches 91.5 and that the speed reaches 63 fps. In the HiSilicon 3516DV300 and the Rockchip Rv1126 Mobile edge computing chips, the speed of the network has been tested for 15 fps.

Multi-criteria ground water potentiality mapping utilizing remote sensing and geophysical data: A case study within Sinai Peninsula, Egypt

Groundwater demand has dramatically increased due to the swift demographic explosion, especially in arid areas, where groundwater is considered the main source for all purposes. Thus, this research integrates climatological, lithological, structural, topographical, hydro-morphological, and geoelectrical data to explore groundwater potential zones in the central part of Sinai Peninsula, Egypt using the GIS-based Analytic Hierarchy Process (AHP). Seven thematic layers of soil moisture, rainfall, normalized difference vegetation index, drainage density, lineament density, slope, and land use/land cover were built from different remote sensing data sets. The eighth layer represents a high-resolution lithological map of the study area, constructed utilizing the power of the support vector machine over Sentinel 2 data and accurately assessed with a previously published geological map. Ground Water Potentiality Map (GWPM) was constructed and highlighted four main areas as promising zones. Comprehensive geoelectrical analysis was executed through seventeen deep vertical electrical soundings (VESs) using Schlumberger configuration, isoresistivity mapping, and geoelectric cross-sections along five different profiles. 3D view of the studied area's subsurface geological and structural pattern with groundwater flow direction specification, and adequate aquifer characterization, revealed four main geoelectrical units. Geoelectrical data results reasonably coincided with remote sensing data findings in highlighting three freshwater potential zones. Furthermore, the study strongly recommends integrating low-cost remote sensing datasets in narrowing the zone to be intensively investigated using further costly geophysical approaches or drilling test boreholes.

Insights into detailed hierarchical puncture-resistance for Bombyx mori silkworm cocoons

Silkworm cocoons illustrate excellent puncture-resistance performance after an insight into their layers while a clear understanding of the correlation between the excellent puncture property and the silk secondary structure is still lacking. Herein, we peeled silkworm cocoon into eight layers, and a combination of examination techniques including scanning electron microscopy, tensile mechanical test, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction were applied to figure out the morphologies (surface and cross-section view), mechanical properties, secondary structure, the content of β-sheet, and crystallinity of each layer's fibroin after degumming. The results indicated that the fifth layer offers a higher level of puncture-resistance than the other layers except for the eighth layer. Additionally, a high content level of β-sheet structure and high crystallinity gives rise to the high puncture strength as for hierarchical silk fibers. In general, the new finding holds great potential inspiration for the design of puncture-resistant composites.

Consideration of Lamination Structural Analysis in a Multi-Layered Composite and Failure Analysis on Wing Design Application.

A finite element (FE) model is developed to study the structural performance on a composite wing of a UAV with a tubercle design at the leading edge of the wing. The experimental study of the designation of the composite at the wing skin is carried out to prove the simulation validity through material characteristics. In this paper, the numerical modeling for simulation is highlighted to correlate the process parameter setting of simulation replicating the actual experimental tests. The percentage difference was calculated to be 11.1% by tensile and 10.47% by flexural. The numerical work applied the study of FE analysis and developed a standardized numerical approach for structural optimization, known as FE-ACP simulation. The significant findings of deformation are obtained according to Schrenk’s aerodynamic loading, while the prediction of failure mode of Tsai–Wu under interaction among stresses and strains was acquired at the seventh and eighth layer of both spars.

Defending against insider threats with network security's eighth layer

It would be an understatement to say 2020 was a year of change, but here we are in March 2021, a world away from March 2020. As the UK Government juggles the socio-economic impacts of Covid-19 and now Brexit, daily news briefings are announcing new guidelines and initiatives to tackle a whole host of problems old and new yet it feels like the growing cyber security threat has been pushed to the bottom of the importance list. With the changes in work practices brought about by the pandemic, security teams have found themselves going back to basics. One area that needs special attention is the so-called ‘layer eight’ – the user. Organisations need to look at how they can reduce deliberate or inadvertent threats from insiders as working from home becomes the new normal. Businesses must implement strict network security policies, as well as looking at the role that the entire organisation plays in network security strategies, argues Phil Chapman of Firebrand Training.

Psychosocial needs of adolescents and young adults with eczema: A secondary analysis of qualitative data to inform a behaviour change intervention

This study aimed to explore adolescents and young adults' experiences of symptoms related to their eczema in order to determine their psychosocial needs. A secondary qualitative analysis of two data sources collected through semi-structured interviews for two different projects, SKINS project and Eczema Care Online project. In total, there were 28 transcripts with adolescents and young adults with eczema having a mean age of 19.5years available to analyse. Interview data were collected from face-to-face interviews that were recorded and transcribed. Inductive thematic analysis explored data about symptoms and organized according to psychosocial needs. Adolescents and young adults with eczema experience both visible symptoms (such as flaky, dry, and inflamed skin) and invisible symptoms (such as itch, pain, exhaustion, and mental distress) that elicit different psychosocial needs. These psychosocial needs are to (i) be understood; (ii) be perceived as normal; and (iii) receive emotional support. Interviewees described a struggle between wanting their peers and family to understand but take their eczema seriously whilst not wanting to stand out and instead to be perceived as 'normal', which they would define as being perceived as other adolescents. This has implications on behaviours, such as seeking support, avoiding going out, hiding their skin, as well as emotional implications, such as social isolation and feeling anxious and low. Having a better understanding of young people's experiences and psychosocial needs will provide a framework on how best to support adolescents and young adults when managing symptoms related to eczema. Statement of contribution What is already known on this subject? Eczema has a high impact on children and is considered a burden by children and adults with eczema. However, it is unclear what impact eczema has on adolescents and young adults. Adolescents and young adults with chronic conditions are known to be vulnerable to negative psychosocial outcomes but psychosocial needs and how to best support this age group with eczema are unknown What does this add? Three psychosocial needs were developed from evaluating the impact of visible and invisible symptoms of eczema: The need to feel understood (mostly reflective of invisible symptoms such as itch and pain and visible symptoms such as scratching). The need to be perceived as 'normal': visible symptoms such as flaky, inflamed skin make them stand out in comparison with their peers and a need emerged to blend in. The need for emotional support: adolescents and young adults searched for this from their health care providers, from shared experiences and from online resources. Adolescents and young adults with eczema appear to feel ambivalent about wishing the impact of the condition to be acknowledged whilst wishing the condition to be invisible to others. This ambivalence had further impact on feeling self-conscious, seeking support, and dealing with unsolicited advice.

Why Do Colloidal Wurtzite Semiconductor Nanoplatelets Have an Atomically Uniform Thickness of Eight Monolayers?

Herein we employed a first-principles method based on density functional theory to investigate the surface energy and growth kinetics of wurtzite nanoplatelets to elucidate why nanoplatelets exhibit a uniform thickness of eight monolayers. We synthesized a series of wurtzite nanoplatelets (ZnSe, ZnS, ZnTe, and CdSe) with an atomically uniform thickness of eight monolayers. As a representative example, the growth mechanism of 1.39 nm thick (eight monolayers) wurtzite ZnSe nanoplatelets was studied to substantiate the proposed growth kinetics. The results show that the growth of the seventh and eighth layers along the [112̅0] direction of 0.99 nm (six monolayers) ZnSe magic-size nanoclusters is accessible, whereas the growth of the ninth layer is unlikely to occur because the formation energy is large. This work not only gives insights into the synthesis of atomically uniform thick wurtzite semiconductor nanoplatelets but also opens up new avenues to their applications in light-emitting diodes, catalysis, detectors, and lasers.

Three-dimensional grain growth during multi-layer printing of a nickel-based alloy Inconel 718

Heterogeneous grain structure is a source of the inhomogeneity in structure and properties of the metallic components made by multi-layer additive manufacturing (AM). During AM, repeated heating and cooling during multi-layer deposition, local temperature gradient and solidification growth rate, deposit geometry, and molten pool shape and size govern the evolution of the grain structure. Here the effects of these causative factors on the heterogeneous grain growth during multi-layer laser deposition of Inconel 718 are examined by a Monte Carlo method based grain growth model. It is found that epitaxial columnar grain growth occurs from the substrate or previously deposited layer to the curved top surface of the deposit. The growth direction of these columnar grains is controlled by the molten pool shape and size. The grains in the previously deposited layers continue to grow because of the repeated heating and cooling during the deposition of the successive layers. Average longitudinal grain area decreases by approximately 80% when moving from the center to the edge of the deposit due to variable growth directions dependent on the local curvatures of the moving molten pool. The average horizontal grain area increases with the distance from the substrate, with a 20% increase in the horizontal grain area in a short distance from the third to the eighth layer, due to competitive solid-state grain growth causes increased grain size in previous layers.

Ring-core method in determining the amount of non-uniform residual stress in laminated composites: experimental, finite element and theoretical evaluation

Residual stresses in composite constructions are created because of non-uniform contraction of layers during cooling from curing to ambient temperature. The aim of this study is to investigate the feasibility of incremental ring-core method to estimate non-uniform residual stresses in various laminates of polymer matrix composites. To carry out this test, glass/epoxy specimens were selected in two different types of symmetric cross-ply laminate $$\left( \left[ 0^{\circ }_{4}/90^{\circ }_{4}\right] _{S}\right) $$ and symmetric quasi-isotropic laminate $$\left( \left[ 0^{\circ }_{2}/\pm 45^{\circ }/90^{\circ }_{2}\right] _{S}\right) $$ . The samples were created using hand layup and vacuum bagging. By experimental tests, released strains measured during milling process and coefficient factors for every annular groove machining operations were obtained by finite element modeling. As well, residual stresses were calculated by classical lamination plate theory. For symmetric cross-ply, the maximum difference between experimental and theoretical results was about 16%, which was observed in the first and eighth layers. Symmetric quasi-isotropic specimen showed also good agreement between the results and the maximum measurement error of 8% was observed. For the mentioned two cases, summation of components of the residual stress in all directions is near to zero. The results of this study show that in the ring-core method, because of the nature and higher volume of material removal than other methods, values of residual stress released are higher and the results have a good consistency compared with the theoretical values.

Atomic diffusion in the Fe [0 0 1] ∑ = 5 (3 1 0) and (2 1 0) symmetric tilt grain boundary

Both the formation and diffusion activation energies of single vacancy migrating intra-layer and inter-layer near the Fe [001] Σ=5 (310) and (210) symmetric tilt grain boundaries have been calculated by using the MAEAM and a MD method. From energy minimization, the vacancy concentration in the second layer is higher than the one in the other layers for both (310) and (210) STGBs. By the diffusion activation energies of the vacancies migrating intra-layer and inter-layer, the vacancies located from the first to the eighth layers of (310) STGB as well as the ones located from the first to the tenth layers of (210) STGB are favorably migrated to the second layer. Thus there is a vacancy aggregation tendency to the second layer near the grain boundary. For the vacancy migrating intra-layer and inter-layer, the influences of the grain boundary are respectively as far as to the fifth and eighth layers for (310) STGB as well as to the sixth and tenth layers for (210) STGB.

Agrobacterium tumefaciens-Mediated Transformation of Maize Endosperm as a Tool to Study Endosperm Cell Biology

Developing maize (Zea mays) endosperms can be excised from the maternal tissues and undergo tissue/cell-type differentiation under in vitro conditions. We have developed a method to transform in vitro-grown endosperms using Agrobacterium tumefaciens and standard binary vectors. We show that both aleurone and starchy endosperm cells can be successfully transformed using a short cocultivation with A. tumefaciens cells. The highest transformation rates were obtained with the A. tumefaciens EHA101 strain and the pTF101.1 binary vector. The percentage of aleurone cells transformed following this method varied between 10% and 22% whereas up to the eighth layer of starchy endosperm cells underneath the aleurone layer showed transformed cells. Cultured endosperms undergo normal cell type (aleurone and starchy endosperm) differentiation and storage protein accumulation, making them suitable for cell biology and biochemical studies. In addition, transgenic cultured endosperms are able to express and accumulate epitope-tagged storage proteins that can be isolated for biochemical assays or used for immunolabeling techniques.

Efficacy of spinosad in layer-treated wheat against five stored-product insect species

The biological insecticide spinosad was evaluated in laboratory bioassays as a surface treatment for wheat to control adult Rhyzopertha dominica, Sitophilus oryzae and three psocid species, Liposcelis paeta, L. bostrychophila, and Lepinotus reticulatus. Spinosad was applied at 1 ppm to 35 g of wheat placed in a vial or to the upper one half, one fourth, or one eighth layer of the wheat; insects were either added to the vials before or after the wheat. When R. dominica were introduced into the vials after the wheat, mortality was 100% except for 83% mortality in the one eighth layer treatment. In contrast, when adults were placed in the vials before the wheat, mortality was 100% only when all of the wheat was treated. Mortality of S. oryzae was lower compared to R. dominica but there was some evidence of upward movement into the treated layers. Mortality of L. paeta and L. bostrychophila was <50% when the entire quantity was treated, in contrast to 100% mortality of L. reticulatus. However, for all psocid species, overall mortality decreased with decreasing depth of the treated layer. The results of this laboratory study show that while spinosad has some effectiveness as a layer treatment on a column of wheat, efficacy will be dependent on the target species, the depth of the treated layer, and the upward or downward mobility of the insect species.

The effect of heat treatment on the physical properties of sol–gel derived ZnO thin films

Zinc oxide (ZnO) thin films were deposited on microscope glass substrates by sol–gel spin coating method. Zinc acetate (ZnAc) dehydrate was used as the starting salt material source. A homogeneous and stable solution was prepared by dissolving ZnAc in the solution of monoethanolamine (MEA). ZnO thin films were obtained after preheating the spin coated thin films at 250 °C for 5 min after each coating. The films, after the deposition of the eighth layer, were annealed in air at temperatures of 300 °C, 400 °C and 500 °C for 1 h. The effect of thermal annealing in air on the physical properties of the sol–gel derived ZnO thin films are studied. The powder and its thin film were characterized by X-ray diffractometer (XRD) method. XRD analysis revealed that the annealed ZnO thin films consist of single phase ZnO with wurtzite structure (JCPDS 36-1451) and show the c-axis grain orientation. Increasing annealing temperature increased the c-axis orientation and the crystallite size of the film. The annealed films are highly transparent with average transmission exceeding 80% in the visible range (400–700 nm). The measured optical band gap values of the ZnO thin films were between 3.26 eV and 3.28 eV, which were in the range of band gap values of intrinsic ZnO (3.2–3.3 eV). SEM analysis of annealed thin films has shown a completely different surface morphology behavior.

In situ determination of Sb distribution in Sb/GaAs(0 0 1) layer for high-density InAs quantum dot growth

An Sb-adsorbed GaAs(0 0 1) substrate that serves as a template for high-density InAs quantum dot (QD) growth was investigated using in situ X-ray diffraction. The Sb distribution in the top eight layers from the surface was determined by crystal truncation rod scattering analysis. It was found that Sb atoms penetrated to the eighth layer when GaAs(0 0 1) came in contact with an Sb environment. The amounts of Sb in the first and second layers were, however, saturated at 1 3 atomic layer (AL) and 2 3 AL, respectively. A comparison between the X-ray results and atomic force microscopy observations of the QD density showed that the formation of high-density QDs is correlated with the total amount of Sb in the surface and subsurface layers.

Structural analysis of the c(4 × 2) reconstruction in Si(0 0 1) and Ge(0 0 1) surfaces by low-energy electron diffraction

The c(4 × 2) structures in (0 0 1) surfaces of Si and Ge have been studied by low-energy electron diffraction (LEED). Using a proper cleaning method for the Si surface, we were able to observe clear c(4 × 2) LEED patterns up to incident energy of ∼400 eV as well as the Ge surface. Extensive experimental intensity–voltage curves allowed us to optimize the asymmetric dimer model up to the eighth layer (including the dimer layer) in depth in the dynamical LEED calculation. Optimized structural parameters are almost the same for the Si and Ge except for the height of the buckled-up atom of the asymmetric dimer. For the Ge surface, the structural parameters are in excellent agreement with those obtained by a previous theoretical calculation. The tilt angle and bond length of the dimer are 18 ± 1 (19 ± 1)° and 2.4 ± 0.1 (2.5 ± 0.1) Å for the Si(0 0 1) (Ge(0 0 1)), respectively.

Buildup Mechanism for Poly(l-lysine)/Hyaluronic Acid Films onto a Solid Surface

The formation of a new kind of biocompatible film based on poly(l-lysine) and hyaluronic acid (PLL/HA) by alternate deposition of PLL and HA was investigated. Optical waveguide lightmode spectroscopy, streaming potential measurements, atomic force microscopy, and quartz crystal microbalance (QCM) were used to analyze the different aspects of the buildup process such as the deposited mass after each new polyelectrolyte adsorption, the overall surface charge of the film, and its morphology. As for “conventional” polyelectrolyte multilayer systems, the driving force of the buildup process is the alternate overcompensation of the surface charge after each PLL and HA deposition. The construction of (PLL/HA)n films takes place over two buildup regimes. The first one is characterized by the formation of isolated islands that grow both by addition of new polyelectrolytes on their top and by mutual coalescence of the islands. The second regime sets in once a continuous film is formed after the eighth layer pair de...

Cation Distribution and Helimagnetic Structure of the Ba2(Zn1-xMgx)2Fe12O22System as Revealed by Magnetization Measurements and Neutron Diffraction

Magnetization measurements and neutron diffraction experiments were carried out on single crystals of Ba 2 (Zn 1- x Mg x ) 2 Fe 12 O 22 , where x is the Mg concentration ranging from x =0 to 1.0. The Fe ions present in the octahedral sites have a tendency to decrease with increasing x . The configuration of Fe magnetic moments in the Mg-rich crystal is a distorted helimagnetic one consisting of large and small ferrimagnetic bunches. We have found that there are competing exchange interactions among Fe magnetic moments lying on the forth, fifth and eighth layers of Mg-rich crystal. The exchange integrals J 45 , J 48 and J 58 were determined using the molecular field approximation: J 45 / J 58 =0.365±0.008 and J 48 / J 58 =0.503±0.016 at 9 K. These values provide a clear interpretation of the turn angle of the helix as well as the helimagnetic structure for the Ba 2 (Zn 1- x Mg x ) 2 Fe 12 O 22 system.