Spreading Mode Research Articles

Influence of synchronous grouting on surrounding sandy cobbles during shield tunnelling process: Insights from a scaled model test

Substantial soil deformation around tail-grouting activity is frequently observed during the shield tunnelling process in the sandy cobble strata, which is attributed to the convergence and potential collapse of the soils around the tail-void left behind the shield machine. The stability of the underlying strata is significantly impacted by synchronous grouting inside the tail-void. This study examines four-opening synchronous grouting, which is frequently used in shield tunnelling of metro-tunnels, to analyze the grout-spreading mechanism and soil displacement generated by the synchronous grouting in the sandy cobble layer. Laboratory tests are used to determine the characteristics of grouting mortar and soils in accordance with the similarity theory. The model experiment outcomes show that a rise in the GVR (Grouting-Volume Ratio) can cause the settlement at the ground surface. However, as the GVR improves, the pace of settlement growth diminishes. Additionally, the expanding cover depth of the tunnel contributes to the stability of the soil after synchronous grouting. As observed in the model test, when GVR achieves its maximum amplitude (i.e., GVR = 200 %), the grout mortar cannot spread to the crown of the tail-void, necessitating secondary grouting after the synchronous grouting during tunnelling practice. After grout hardening process, it was discovered that grout material above the tunnel waist was concentrated near the upper grout openings, implying a seepage spreading mode of the grout-mortar at these locations. In contrast, grout material below the tunnel waist was evenly distributed along the periphery of the tail void. The model test outcomes may be utilized as a guide for tail-grouting while shield tunneling in sandy cobble strata.

Numerical and experimental research on axial injection end-burning hybrid rocket motors with polyethylene fuel

This study investigates the end-burning hybrid rocket motors with polyethylene fuel by the numerical simulation and experiment. Based on computational fluid dynamics, a numerical model is developed. The model is validated by two firing tests in this hybrid rocket motor, which uses oxygen and polyethylene as propellants. The results show that the numerical and experimental data are in good agreement, and the error of the chamber pressure is less than 2.63%. Based on the simulation mode, the blowoff limit of the end-burning hybrid rocket motors is investigated. When the nozzle throat diameter and the inner diameter of grain are large, it is more difficult for the hybrid rocket motor to achieve end-burning mode, i.e., the flame spreading is prevented in the narrow duct. The main reason is that when the nozzle throat and the grain port are large, chamber pressure and oxidizer flow velocity are low. Therefore, the friction velocity considering the pressure and flow velocity is proposed. The critical friction velocity is about 4.054–4.890 m/s in the hybrid rocket motors. When the friction velocity exceeds the critical friction velocity, the combustion mode in hybrid rocket motors changes from the flame spreading mode to the end-burning mode. Moreover, the regression rate formula is obtained by fitting, which shows that the regression rate has a good correlation with combustion chamber pressure. The critical friction velocity and regression rate formula can provide an important reference for end-burning hybrid rocket motors.

Intracellular mechanics and TBX3 expression jointly dictate the spreading mode of melanoma cells in 3D environments

Cell stiffness and T-box transcription factor 3 (TBX3) expression have been identified as biomarkers of melanoma metastasis in 2D environments. This study aimed to determine how mechanical and biochemical properties of melanoma cells change during cluster formation in 3D environments. Vertical growth phase (VGP) and metastatic (MET) melanoma cells were embedded in 3D collagen matrices of 2 and 4 mg/ml collagen concentrations, representing low and high matrix stiffness. Mitochondrial fluctuation, intracellular stiffness, and TBX3 expression were quantified before and during cluster formation. In isolated cells, mitochondrial fluctuation decreased and intracellular stiffness increased with increase in disease stage from VGP to MET and increased matrix stiffness. TBX3 was highly expressed in soft matrices but diminished in stiff matrices for VGP and MET cells. Cluster formation of VGP cells was excessive in soft matrices but limited in stiff matrices, whereas for MET cells it was limited in soft and stiff matrices. In soft matrices, VGP cells did not change the intracellular properties, whereas MET cells exhibited increased mitochondrial fluctuation and decreased TBX3 expression. In stiff matrices, mitochondrial fluctuation and TBX3 expression increased in VGP and MET, and intracellular stiffness increased in VGP but decreased in MET cells. The findings suggest that soft extracellular environments are more favourable for tumour growth, and high TBX3 levels mediate collective cell migration and tumour growth in the earlier VGP disease stage but play a lesser role in the later metastatic stage of melanoma.

C-E Translation of Micro Film Spreading Mode and Local Opera Development Path under the Guidance of Skopos Theory

With the continuous acceleration of globalization in today’s world, international cultural exchanges are becoming more and more frequent. However, the development of Chinese opera culture is facing challenges in contemporary era. As a new communication channel, unique advantages of micro-film can provide a new path for the development of local opera. The source text, Micro Film Spreading Mode and Local Opera Development Path, aims at passing information, with practical, informative and communicative functionality, so its translation must meet the actual needs of the target language readers to understand the content. Under the guidance of Skopos Theory on the translation of academic text, translation strategies such as literal translation, addition, and conversion have been adopted to ensure the translated text to be accurate in meaning as much as possible to the source text, and the target language is similar to that of the original author in style.

Vine Spread for Superpixel Segmentation.

Superpixel is the over-segmentation region of an image, whose basic units "pixels" have similar properties. Although many popular seeds-based algorithms have been proposed to improve the segmentation quality of superpixels, they still suffer from the seeds initialization problem and the pixel assignment problem. In this paper, we propose Vine Spread for Superpixel Segmentation (VSSS) to form superpixel with high quality. First, we extract image color and gradient features to define the soil model that establishes a "soil" environment for vine, and then we define the vine state model by simulating the vine "physiological" state. Thereafter, to catch more image details and twigs of the object, we propose a new seeds initialization strategy that perceives image gradients at the pixel-level and without randomness. Next, to balance the boundary adherence and the regularity of the superpixel, we define a three-stage "parallel spreading" vine spread process as a novel pixel assignment scheme, in which the proposed nonlinear velocity for vines helps to form the superpixel with regular shape and homogeneity, the crazy spreading mode for vines and the soil averaging strategy help to enhance the boundary adherence of superpixel. Finally, a series of experimental results demonstrate that our VSSS offers competitive performance in the seed-based methods, especially in catching object details and twigs, balancing boundary adherence and obtaining regular shape superpixels.

A topology-based evaluation of resilience on urban road networks against epidemic spread: Implications for COVID-19 responses.

Road closure is an effective measure to reduce mobility and prevent the spread of an epidemic in severe public health crises. For instance, during the peak waves of the global COVID-19 pandemic, many countries implemented road closure policies, such as the traffic-calming strategy in the UK. However, it is still not clear how such road closures, if used as a response to different modes of epidemic spreading, affect the resilient performance of large-scale road networks in terms of their efficiency and overall accessibility. In this paper, we propose a simulation-based approach to theoretically investigate two types of spreading mechanisms and evaluate the effectiveness of both static and dynamic response scenarios, including the sporadic epidemic spreading based on network topologies and trajectory-based spreading caused by superspreaders in megacities. The results showed that (1) the road network demonstrates comparatively worse resilient behavior under the trajectory-based spreading mode; (2) the road density and centrality order, as well as the network's regional geographical characteristics, can substantially alter the level of impacts and introduce heterogeneity into the recovery processes; and (3) the resilience lost under static recovery and dynamic recovery scenarios is 8.6 and 6.9%, respectively, which demonstrates the necessity of a dynamic response and the importance of making a systematic and strategic recovery plan. Policy and managerial implications are also discussed. This paper provides new insights for better managing the resilience of urban road networks against public health crises in the post-COVID era.

EFFECT OF SOWING METHODS ON THE YIELD AND YIELD COMPONENTS OF WHEAT UNDER TWO SEED RATES AT SULAIMANI REGION

This experiment was implemented in the College of Agricultural Engineering Sciences fields in Bakrajo-Sulaymaniyah in two consecutive cropping seasons, 2017-2018 and 2018-2019. Two seeding rates were applied with three seeding methods, seed drill, conventional scattering pattern by centrifugal seeds spreader, and an un familiar pattern in the region, which is the overlapping pattern of grain spreading lines by the distributor. the coefficient of variance (% CV) for seeds had the best value in comparison to overlap spreading, which in turn was better than conventional scattering was 1.1, 8.2 and 47.2 for seed rate of 200 kg ha-1 and 1.7, 7.6, and 44.8 for seed rate of 160 kg ha-1 respectively. The seeding rate 200 kg ha-1 was significantly recorded higher averages for most of the studied traits. The sowing patterns had significantly superior to the overlapped grain spreading lines when it recorded 106.23 cm plant high, 341.47 spikes m-2, 43.1 grains spike-1, 38.7 g thousand grains weight, 3623.74 kg ha-1, 11379.03 kg ha-1 and 0.32 harvest index. The overlapped spreading mode also significantly superior to the conventional mode of prose.

Modeling network vulnerability of urban rail transit under cascading failures: A Coupled Map Lattices approach

In terms of urban rail transit network vulnerability, most studies have focused on the changes of network topology and functional characteristics under disruptive events while ignoring the impacts of cascading failures on network performance. In this study, an improved Coupled Map Lattices model is proposed to address the evolution process of cascading failures on rail transit network. Particularly, the model quantifies important factors of cascading failures integrating quantitative failure spreading mode, anti-risk ability of stations, and perturbation index. The rail transit network vulnerability is then modeled addressing numbers of failed stations, degree of affected passengers, and loss of passenger travel time as a result of cascading failures. The methodology is applied to the metro network of Shanghai, China. Results show that the propagation of network cascading failure depends on the station's anti-risk ability, geographical location, and type of adjacent stations. Stations located in the urban center area are more susceptible to failures of adjacent stations. Furthermore, higher affected passenger volume and station coupling strength would lead to more serious and rapid spreading of failures, and thus more vulnerable of the metro system. However, the anti-risk ability of stations could effectively resist the spread of failures in the early stage, and stations with higher topology redundancy demonstrate stronger anti-risk ability.

The Mode of Trench-Parallel Subduction of the Middle Ocean Ridge

Trench-parallel subduction of mid-ocean ridges occurs frequently in plate motion history, such as along the western boundary of the Pacific plate in the early Cenozoic and along the eastern boundary of the Pacific plate at present. Such subduction may strongly alter the surface topography, volcanic activity and slab morphology in the mantle, whereas few studies have been conducted to investigate its evolutionary process. Here, we construct a 2-D viscoelastoplastic numerical model to study the modes and key parameters controlling trench-parallel subduction of mid-ocean ridges. Our model results show that the subduction modes of mid-ocean ridges can be primarily categorized into three types: the fast spreading mode, the slow spreading mode, and the extinction mode. The key factor controlling these subduction modes is the relative motion between the foregoing and the following oceanic plates, which are separated by the mid-ocean ridge. Different subduction modes exert different surface geological expressions, which may explain specific evolutionary processes related to mid-ocean ridge subduction, such as topographic deformation and the eruption gap of volcanic rocks in East Asia within 55–45 Ma and in the western North American plate during the late Cenozoic.

Magmato-tectonic mechanism of Southwest Indian Ridge (49°-50°E) inferred from quantitative morphotectonic analysis based on high-resolution multibeam bathymetry

Southwest Indian Ridge (SWIR) is a typical ultra-slow spreading ridge which has been extensively studied based on geophysical survey, geochemical sampling and morphological feature extraction. In this paper, based on the high-resolution multibeam bathymetric data, we extract seven types of topography, including fault, axial rift, axial volcanic ridge (AVR), axial trough, AVR's remnant, volcanic cone and oceanic core complex (OCC). We perform quantitative morphotectonic statistic, verifying the relations between the topography and magmato-tectonic mechanism of SWIR 49–50°E. The analyzed results of flank topography show that the average seafloor depth of the southern flank is shallower than that of the northern flank. The Total Cumulative Length of the faults in the northern and southern flank is 624.6 km and 948.2 km. The number, Total density, Average Length and Maximum Length of the faults in the southern flank are higher than those in the northern flank. An OCC and detachment faults locate in the southern flank. The asymmetry in flank topography indicates the asymmetric spreading mode of the study area. The analyzed results of the axial topography show that AVRs and troughs develop in the rift. The rift is narrower and shallower in the AVR regions, and wider and deeper in the trough regions. These observations support the partition of magmatic and less-magmatic stretching in the study area, and indicate the relation between the variation of rift's depth-width and the magmato-tectonic accretion.

COVID-19 Pandemic/Lockdown and its Impact on Sustainable Access to Safe Water in the Developing World: A Case Study

COVID-19 pandemic has impacted on the global socio-economic spectrum, including water accessibility especially in developing countries. The global achievement in water access subsector at the end of MDGS could be jeopardized with the unabated prevalence of a novel and contagious disease which knows no bound. With the pandemic and its spreading mode through close contact which brought about the total lockdown of the global community, accessibility to improved water could have been restricted. To assess the impact of the disease/lockdown on water access, a survey was conducted during the lockdown-free days across randomly selected inhabitants of Iwo, Osun State, Nigeria. Data analysis was descriptive. The results revealed that the disease/lockdown restricted the movement of the respondents to search for potable water. Respondents adopted various strategies to ensure water availability in their homes including night fetching (12.2%), rotation (16.2%), purchase (1.4%), surface sources (8.8%) among others. About 78.3% either agreed or strongly agreed that the pandemic had pronounced impacts on domestic water supply and subjected them to untold hardship searching for water while trying to avoid physical contact. This work, therefore recommends review of global target on water access to ensure each house is connected to safe and sustainable water sources.

Scale effect of amount of molten corium and outlet diameters on corium spreading

The difference in the amount of molten corium and outlet diameter influences the corium spreading, which is essential to enhance the safety of nuclear power plants. To investigate this phenomenon, in this work, the influence of the scale relation between the amount of molten metal and the outlet diameter (L/D) on the corium spreading was investigated. Experiments involving the spreading of a molten corium simulant on a stainless-steel plate were performed under various nozzle sizes and sample amounts. The spreading behavior during the experiment was recorded via a video camera. Based on the obtained experimental data, a dimensionless analysis was performed to determine the dominant parameters responsible for the spreading phenomena, and spreading models were developed to infer the solidified area and thickness. The results indicated that the spreading mode may vary at approximately L/D = 6, owing to the change in the force balance represented by the Weber and Reynolds numbers. The developed spreading model considering both the length and thickness values can help understand and predict the spreading of the fuel debris in the first floor.

Drugs For Ayurvedic Hand Sanitizer And Nasal Spray And Its Method Of Preparation

Infection causing microbes spread through the air, water, contaminated food, cloth, equipment or from infected person to healthy one. The evidence collected on spreading mode of COVID-19 is mostly through skin contact and respiratory droplets. However, just in contact with the microbe is not enough to cause the disease. Reaching the germ to the internal body is the critical step involved in the manifestation of illness. Contact transmission for the sign of disease in an individual can occur from skin to the inner body especially when the infected part (mostly hands) reaches the mucous membrane of open cavities such as mouth, nose, eyes or open wound. Therefore the use of good quality sanitizers to prevent infections such as COVID-19 is one of the critical measures.Ayurveda is a rich source of vast information on therapeutic potentials of numerous herbs. Many simple to complex formulations can be prepared by using the therapeutic attributes of these herbs. Therefore in the present work, an attempt has been made to initiate the manufacturing of Ayurveda hand sanitizers based on various Ayurvedic medicated drugs mentioned in Samhitas, as developing countries such as India are facing a shortage of hand sanitizers which is a must prevent the spread of COVID-19. The shortage has resulted in an internal price hike, and thus there is a need for a homemade affordable way of sanitizing hands. Therefore by using a combination of antimicrobial, disinfectant, anti-allergic, skin disease curing herbs along can be recommended for the preparation of Ayurveda hand sensitizers. By using similar herbs, nasal spray and aerosols for cleaning and increasing the strength of the respiratory tract can also be prepared.

Magmatic and tectonic segmentation of the intermediate-spreading Costa Rica Rift—a fine balance between magma supply rate, faulting and hydrothermal circulation

SUMMARY 3-D tomographic modelling of wide-angle seismic data, recorded at the intermediate-spreading Costa Rica Rift, has revealed a P-wave seismic velocity anomaly low located beneath a small overlapping spreading centre that forms a non-transform discontinuity at the ridge axis. This low velocity zone displays a maximum velocity anomaly relative to the ‘background’ ridge axis crustal structure of ∼0.5 km s−1, has lateral dimensions of ∼10 × 5 km, and extends to depths ≥2.5 km below the seabed, placing it within layer 2 of the oceanic crust. We interpret these observations as representing increased fracturing under enhanced tectonic stress associated with the opening of the overlapping spreading centre, that results in higher upper crustal bulk porosity and permeability. Evidence for ongoing magmatic accretion at the Costa Rica Rift ridge axis takes the form of an axial magma lens beneath the western ridge segment, and observations of hydrothermal plume activity and microearthquakes support the presence of an active fluid circulation system. We propose that fracture pathways associated with the low velocity zone may provide the system through which hydrothermal fluids circulate. These fluids cause rapid cooling of the adjacent ridge axis and any magma accumulations which may be present. The Costa Rica Rift exists at a tipping point between episodic phases of magmatic and tectonically enhanced spreading. The characteristics inherited from each spreading mode have been preserved in the crustal morphology off-axis for the past 7 Myr. Using potential field data, we contextualize our seismic observations of the axial ridge structure at the whole segment scale, and find that the proposed balance between magmatic and tectonically dominated spreading processes observed off-axis may also be apparent along-axis, and that the current larger-scale magma supply system at the Costa Rica Rift may be relatively weak. Based on all available geophysical observations, we suggest a model for the inter-relationships between magmatism, faulting and fluid circulation at the Costa Rica Rift across a range of scales, which may also be influenced by large lithosphere scale structural and/or thermal heterogeneity.

РАСЧЕТ БУРНОГО ПОТОКА ВОДЫ НА ВЫХОДЕ ИЗ КРУГЛОЙ ТРУБЫ В НИЖНЕМ БЬЕФЕ ВОДОПРОПУСКНЫХ СООРУЖЕНИЙ

The article proposes a mathematical modeling of the rapid flow spreading in the wide downstream of the culvert depending on the flow rate, the relative expansion of the downstream and the depth of the water at the outlet of the round pipe. An open water flow is considered in a non-pressure spreading mode. When the Froude numbers are large than four in the channel with a relative expansion of b = 3–7, pairing is established according to the type of free flow of a two-dimensional turbulent flow, the depths and flow rates at each point, the geometry of the free flow zone are determined. The flow parameters are calculated at any point of the free flow area using the Maple software package. The adequacy of the model extreme current line with the experimental one is shown.

Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus.

One important feature of the major opportunistic human pathogen Staphylococcus aureus is its extraordinary ability to rapidly acquire resistance to antibiotics. Genomic studies reveal that S. aureus carries many virulence and resistance genes located in mobile genetic elements, suggesting that horizontal gene transfer (HGT) plays a critical role in S. aureus evolution. However, a full and detailed description of the methodology used to study HGT in S. aureus is still lacking, especially regarding natural transformation, which has been recently reported in this bacterium. This work describes three protocols that are useful for the in vitro investigation of HGT in S. aureus: conjugation, phage transduction, and natural transformation. To this aim, the cfr gene (chloramphenicol/florfenicol resistance), which confers the Phenicols, Lincosamides, Oxazolidinones, Pleuromutilins, and Streptogramin A (PhLOPSA)-resistance phenotype, was used. Understanding the mechanisms through which S. aureus transfers genetic materials to other strains is essential to comprehending the rapid acquisition of resistance and helps to clarify the modes of dissemination reported in surveillance programs or to further predict the spreading mode in the future.

Oxygen Vacancies in CrO2: The Influences to Half Metallicity and the Formation Mode

The electronic structures of chromium dioxide (CrO2) with different concentrations and distributions of oxygen vacancy were investigated by first-principle calculations based on density functional theory. It was found that even at fairly high vacancy concentration, the half metallicity of CrO2 keeps intact as long as oxygen vacancies do not pair in the same octahedron; when two vacancies appear in one octahedron, the half metallic nature of CrO2 may be severely weakened or completely destroyed even at much lower vacancy concentration depending on the vacancy-pair configuration. Our results suggest that the half metallicity of CrO2 is more sensitive to the relative positions of oxygen vacancies than to the vacancy concentration. By investigating the position dependence of the formation energy, the formation and the spreading mode of oxygen vacancies were discussed. The results show that once an oxygen vacancy forms, the next oxygen vacancy tends to appear in the equatorial plane of the same octahedron to reduce Cr4+ to Cr3+. This kind of pairing nature indicates that the oxygen vacancies may tend to spread in a planar mode along the [00l] direction.

Thin three-dimensional droplets on an oscillating substrate with contact angle hysteresis.

Recent experiments [P. Brunet, J. Eggers, and R. D. Deegan, Phys. Rev. Lett. 99, 144501 (2007)10.1103/PhysRevLett.99.144501] have shown that a liquid droplet on an inclined plane can be made to move uphill by sufficiently strong, vertical oscillations. In order to investigate this counterintuitive phenomenon we use a model in which liquid inertia and viscosity are assumed negligible so that the motion of the droplet is dominated by the applied acceleration due to the oscillation of the plate, gravity, and surface tension. We explain how the leading order motion of the droplet can be separated into a spreading mode and a swaying mode. For a linear contact line law, the maximum rise velocity occurs when these modes are in phase. We show that, both with and without contact angle hysteresis, the droplet can climb uphill and also that, for certain contact line laws, the motion of the droplet can produce footprints similar to experimental results. We show that if the two modes are out of phase when there is no contact angle hysteresis, the inclusion of hysteresis can force them into phase. This in turn increases the rise velocity of the droplet and can, in some cases, cause a sliding droplet to climb.

Evaporation of liquid droplets from a surface of anodized aluminum

The results of study of evaporation of water droplets and NaCl salt solution from a solid substrate made of anodized aluminum are presented in this paper. The experiment provides the parameters describing the droplet profile: contact spot diameter, contact angle, and droplet height. The specific rate of evaporation was calculated from the experimental data. The water droplets or brine droplets with concentration up to 9.1 % demonstrate evaporation with the pinning mode for the contact line. When the salt concentration in the brine is taken up to 16.7 %, the droplet spreading mode was observed. Two stages of droplet evaporation are distinguished as a function of phase transition rate.

Thermal Spreading with Flat-Plate Oscillating Heat Pipes

The thermal performance of a flat-plate oscillating heat pipe operating as a heat spreader was experimentally investigated. The copper flat-plate oscillating heat pipe had overall dimensions of , possessed two layers of minichannels, and was charged with acetone to a filling ratio of approximately 80%. The flat-plate oscillating heat pipe was centrally heated with a square heat source and had a copper pin-fin heat sink attached to its opposite side for crossflowing air at speeds of either 1, 2, or . The results clearly indicated that the flat-plate oscillating heat pipe is capable of operating in the thermal spreading mode, providing for a 10–15% reduction in total thermal resistance (relative to pure copper) and managing heat inputs up to 230 W () with the maximum surface temperature not exceeding 100°C. In addition, the temperature uniformity of the heat sink was greater when attached to the flat-plate oscillating heat pipe, especially for lower Reynolds numbers (airspeeds). A critical heat input was required to initiate the flat-plate oscillating heat pipe, and this heat input increased with Reynolds number. This study further confirms the heating mode directly affects the heat transfer performance of a flat-plate oscillating heat pipe.