Walls Of Box Research Articles

Topographic effects on wave resonance in the narrow gap between fixed box and vertical wall

Multiple coastal and offshore structures deployed side by side with narrow gap may be subject to large-amplitude free surface resonance, which can lead to green water on the deck and cause rapid increase of hydrodynamic loading on structures. Here, the resonant motions of the free surface inside a narrow gap between a fixed box and a vertical wall excited by incident regular waves with various wave heights are simulated using a two-dimensional numerical wave tank. The topographies of plane slopes with different inclinations are deployed in front of the vertical wall. The main focus of this paper is on the influences of the topographical variation on the fluid resonance inside the narrow gap. For the first time, it is found that the fluid resonant frequency decreases monotonously with the topographical slope, and both the amplification of the resonant wave height and the reflection coefficient present a pattern of fluctuation with the slope. For all the topographies considered in this paper, both the fluid resonant frequency and the amplification of the resonant wave height are shown to decrease with the incident wave height; while the variation trend of the reflection coefficient with the incident wave height depends on the topographical slope.

Physics design for a lithium vapor box divertor experiment on magnum PSI

The lithium vapor box divertor is a potential solution for power exhaust in toroidal confinement devices. The divertor plasma interacts with a localized, dense cloud of lithium vapor, leading to volumetric radiation, cooling, recombination, and detachment. To minimize contamination of the core plasma, lithium vapor is condensed on cool (300–400°C) baffles upstream of the detachment point. Before implementing this in a toroidal plasma device with a slot divertor geometry, we consider an experiment with a scaled baffled-pipe geometry in the high-power linear plasma device Magnum-PSI. Three 15 cm-scale open cylinders joined by 6 cm diameter ‘nozzles’ are positioned on the plasma beam axis upstream of a target. The central box may be loaded with several tens of grams of lithium, which can be evaporated at 650°C to produce a vapor predicted, using a simple plasma-neutral interaction model, to be dense enough to cause volumetric detachment in the plasma. The power delivered to the target and box walls as measured by increases in their temperatures after a 10 s plasma pulse can be compared to determine the effectiveness of the vapor in detaching the plasma. Direct Simulation Monte Carlo simulations are performed to estimate the flow rates of lithium vapor between the boxes and to estimate the trapping of H2 delivered by the plasma in the boxes, which could inadvertently lead to detachment. Details of the geometry, simulations, and possible diagnostic techniques are presented.

Single molecule analysis of structural fluctuations in DNA nanostructures.

DNA origami is an excellent tool for building complex artificial nanostructures. Functionalization of these structures provides the possibility of precise organization of matter at the nanoscale. In practice, efforts in this endeavour can be impeded by electrostatic repulsion or other dynamics at the molecular scale, resulting in uncompliant local structures. Using single molecule FRET microscopy combined with coarse-grained Brownian dynamics simulations, we investigated here the local structure around the lid of a DNA origami box, which can be opened by specific DNA keys. We found that FRET signals for the closed box depend on buffer ion concentrations and small changes to the DNA structure design. Simulations provided a view of the global and local structure and showed that the distance between the box wall and lid undergoes fluctuations. These results provide methods to vizualise and improve the local structure of three-dimensional DNA origami assemblies and offer guidance for exercising control over placement of chemical groups and ligands.

Dynamic response and damage analysis of steel box wall under internal blast loading

Different loading conditions, different structural dimensions, or different structural materials will lead to different damage results. In this study, blast experiment of steel box model under internal explosion was conducted and the numerical methods are validated through comparison of experimental and numerical results. Then, a series of multi-box models were built, and a large number of numerical simulations considering two kinds of steel, different plate thickness ranging from 0.005 to 0.025 m, and different TNT explosive mass ranging from 5 to 2000 kg were carried out using the validated numerical methods. Two damage modes, convex damage and concave damage, were observed. The dynamic response and damage mechanism were analyzed, and the results show that the different damage modes of the first wall will lead to different damage results of the second wall. Through dimensional analysis, a two-dimensional dimensionless number for internal blast analysis was suggested. Clear physical meanings are conveyed in the dimensionless number. After that, prediction of the damage modes was studied using the proposed dimensionless number. A damage mode map was plotted based on the two-dimensional dimensionless number, and an empirical equation for rapid prediction of damage mode of steel box wall under internal blast loading is proposed.

Tests of New Box Steel Replaceable Piers Under Axial Compression

A new recoverable box steel bridge column with bottom replaceable piers was proposed. The axial compressive tests were initially performed on fourteen specimens which have three different types of steel replaceable piers. Results demonstrate that all three types of structural measures improve the specimens’ strength and deformation performance. Compared to the installing of the low yield point steel plates, the embedded shell plates and the longitudinal ribs on the box walls result in a greater increase of the specimens’ bearing capacity and ductile performance. When the specimen has the longitudinal ribs installed on the box walls and the smaller space of transverse stiffeners, its bearing capacity is increased. The specimens’ ductility is improved when the space of transverse stiffeners and the height of low yield point steel plates decrease. The specimens’ bearing capacity and ductility are only slightly affected by the variation of the embedded shell’s radian. Finally, a simplified calculation formula for the axial compressive bearing capacity of the bottom replaceable piers is proposed.

Experimental performances of a thermoelectric cooler box with thermoelectric position variations

An experimental performance investigation on thermoelectric cooler box with several positions of the thermoelectric was performed. The cooling system of the cooler box comprised a thermoelectric module model TEC1-12706, a heatsink-fan, an inner heat sink, a bottle of water with a volume of 360 ml. The positions of the thermoelectric were at the top, on the bottom, and on the wall. The inner cooler box size employed was 215 mm × 175 mm × 130 mm, and the thickness of the cooler box walls was 50 mm. The experiment was conducted for about 18,000 s at the open ambient temperature. The power used was constant of about 38.08 W. The results showed that the COP decreased with the times, and the best position of the thermoelectric placement of this study was on the wall.

Comparative Study on Absorbed Dose Distribution of Potato and Onion in X-ray and Electron Beam System by MCNPX2.6 Code

The absorbed dose distribution and depth dose of X-ray and electron irradiation in a phantom of water, a box of onion and potato powder, and a box of fresh onions and potatoes were calculated by using Monte Carlo N-Particle extended (MCNPX2.6) code. Simulation parameters were extracted from a Rhodotron accelerator at Yazd Radiation Processing Center (YRPC). The estimated absorbed dose distribution and depth dose in the water phantom show the well-distributed absorbed dose of 0.8–1.8 kGy for X-ray. This finding is consistent with the experimental results. However, the dose depth and distribution of electron irradiation are inappropriate. As such, the optimum conditions were obtained for electron irradiation by varying box thickness, beam current and distance between energy source and box surface. Optimum energy and current, box wall thickness, and distance between energy source and box surface were also estimated for onion and potato powders and for fresh onions and potatoes to achieve the appropriate dose distribution and desired depth dose of 1–3 kGy for onion and potato powder and 0.1–1 kGy for fresh onions and potatoes. Therefore, appropriate irradiation processes to powders and fresh materials are X-ray and electron irradiation, respectively.

РОЗРОБКА ТА ЗАСТОСУВАННЯ СТАНКОВОГО ОБЛАДНАННЯ ДЛЯ ВИРОЩУВАННЯ ПОРОСЯТ ЗА УМОВ ПРОМИСЛОВОЇ ТЕХНОЛОГІЇ

In the article it is presented the results of the development and application of new technical means and the machine equipment intended for housing and feeding sows with offspring. The expansion of production volumes is impossible without reconstruction of existing premises, replacement and improvement of technological equipment, improvement of the system of housing and feeding. The purpose of this work is a comparative study of the efficiency of the use of new technological equipment designed to improve conditions of housing sow and accelerate the training of piglets to early feeding. The research was carried out in the conditions of the industrial complex at the Industrial Meat Company Ltd (STF TOV Agrokombinat “Maiak”) with a production capacity of 6 thousand heads of pigs per year, village of Verkhnia Syrovatka, Sumy district, Sumy region. The main task of the development and improvement of the machine for receiving the farrowings and housing of sows with offspring was to change the way of transforming the partition walls of the fixing box and improve the conditions for activating the game and feed behavior of animals. The achievement of the task is carried out by installing arcuate clamps that restrict the movement of sows, or increase the area of free movement. On a P-shaped bench, a container with a lattice bottomit it is installed a container with bottomit to feed piglets with pre-starter mixed fodder with various specific additives. This container is planted on the axle so that it can rotate freely when the sow, pressing on the button to receive feed. The sows as a result of the search and fodder reflexes pushes the container with a ril, raises and revolves around the axis, and the feed is shaken through the grid bottom on the floor of the machine. The sow chooses the feed, and the piglets mimic it and try to pick it up, which helps to accelerate the training the piglets to the feeding of dry prestarter. Under such a volumetric planing decision of the maschine, the area used for motivated animals more efficiently, more comfortable conditions are created for increasing the motor activity of the sow and the piglets, the process of training the latter to feed and the working conditions of the operator is accelerated. In the course of the research it was determined that the newly developed constructive decisions of the machine in the sows of the experimental groupit was increased motor activity (on 82, min or 73.15%). The duration of consumption of feed in the experimental sows both groups was almost the same. Piglets of the experimental group significantly exceeded their control peers for playing activity (on 46.1 minutes or 26.25%) and the duration of consumption of feed (on 60.1 min, or on 32.27%). The weight of the piglets’ litter in the experimental group was higher, compared with the control at 8.24 kg or 10.76%. Thus, the advantage of a new machine compared to the prototype is to create the best conditions for increasing the activity of the sow and piglets and the faster training of the young piglets to feed. The machine meets the existing principles of the EU countries regarding the welfare provision of sows and piglets and promotes their productivity. Keywords: m achine equipment, pglets, sows, live weight, average daily gain, behavior, feed automatic, bunker self- feeder

Description of complex viewing geometries of fusion tomography diagnostics by ray-tracing.

Ray-tracing techniques are applied to bolometry, a diagnostic where the finite collection volume is particularly sensitive to the machine and detector configuration. A technique is presented that can handle arbitrarily complex aperture and collimator geometries, neglecting reflection effects. Sight lines from the ASDEX Upgrade bolometer foils were ray-traced with a path tracing algorithm, where the optical path is represented by a statistical bundle of ray paths connecting the foil surface with the slit geometry. By using the full 3D machine model for the detector box and first wall, effects such as occlusion and vignetting were included in the calculation of the bolometer's étendue. Inversion matrices calculated with the ray-tracing technique were compared with the more conventional single-ray approach and shown to be naturally more constrained, requiring less regularisation. The two models were tested on a sample radiation scenario, and the common single-ray approximation is shown to be insufficient. These results are particularly relevant for the divertor where strong emission gradients may be present. The technique developed generalises well to arbitrarily complex viewing geometries and collimators, opening up a new design space for bolometer configurations that might not normally have been considered.

Optimization of flow control devices to minimize the grade mixing in steelmaking tundish

The minimization of grade intermixing in a tundish is one of the import concern of steelmakers. Different design and operating parameters of the tundish, as well as flow control devices (FCDs), has been used in last decade by researchers to modify the flow characteristics of melt in the tundish. In the present work, the three-dimensional numerical investigations have been carried out to optimise the design of FCDs in multi-strand tundish by using response surface methodology. The interaction of design parameters i.e., shroud depth, advanced pouring box (APB) wall angle, dam height and dam position has been studied by the response surface plots. An effort has been made to quantify the impact of APB angle and shroud depth. Moreover, these two FCDs have important implications in future for efficient inclusion removal. The quantification of intermixed grade steel in tundish has been made at each strand. Further, average output from all strand has been analyzed and the optimum design of FCDs has been suggested. An important finding from this study is that some FCDs have an adverse impact on mixing in the far zone of the tundish.

Eco-engineering rock pools to a seawall in a tropical estuary: Microhabitat features and fine sediment accumulation

Seawalls made from rock and concrete are engineered to defend coastlines and infrastructure from sea level rise, storm surge and shoreline erosion. However, while they provide a poor substitute for natural intertidal habitat, emerging designs addressing this biodiversity deficit have incorporated eco-engineering concepts with promising results. This study tested whether adding inexpensive household flower boxes (artificial rock pools) to a seawall in a tropical region would support benthic flora and fauna, and whether simple orientation of boxes improves benthic assemblage colonization. Boxes were positioned at mean tide height (1.1 m AHD) along a seawall in tropical Townsville, Australia. Nine boxes were deployed: three positioned vertically on the seawall, while three positioned at 45° facing towards the sea, and three positioned at 45° facing towards the land. Tilting the artificial rock pools at 45° compared overhang walls (simulating rocky shoreline ledge microhabitat) to vertical walls of artificial rock pools. After 12mths, boxes had accumulated (particularly inside on overhang walls compared to outside walls) a greater surface cover of algae and invertebrates. After the second year, box inside walls supported vastly different assemblages compared to outside box walls regardless of orientation, with the most diverse benthic assemblage found on overhang walls, giving support to the conclusion that artificial rock pools on seawalls support more biodiversity (of native species, with no non-indigenous species found) from tilting and creating overhangs. The turbid nature of this coastal region contributed to sediment accumulation at about 25 mm/yr, regardless of box orientation, which may pose maintenance problems (and cost) for managers, and if unchecked could negate any advantages offered by these engineered pool features.

Mechanical properties of ten-egg boxes made of different materials.

This study was conducted to evaluate mechanical properties of ten-egg boxes, which are the most commonly used egg boxes in many countries of Central and South-Eastern Europe. Six ten-egg boxes were tested, two made of cardboard, two made of expanded polystyrene and two made of general purpose solid polystyrene, each from a different producer. There were no significant differences in basic dimensions between tested boxes of various materials, while the significant differences were occurred in weight and box wall thickness. Test included measuring of vertical forces required for deforming complete box and at particular place for each egg in a box till contact with eggs. According to the obtained results, cardboard boxes can provide the best mechanical protection for eggs. The average force required for deforming complete cardboard box was 83.6% higher than for solid polystyrene box, and even 289.5% higher than for expanded polystyrene box. The average force required for deforming cardboard box at particular place for each egg in a box was 60.8% higher than for polystyrene box, and 74.0% higher than for expanded polystyrene box. The disadvantage of cardboard boxes is that they are not resistant to the impact of moisture as polystyrene boxes and in the case of an increase in box moisture due to storage in inappropriate conditions their mechanical resistance decreases.

The multi-axial strength performance of composited structural B-C-W members subjected to shear forces

This paper presents a new method to compute the shear strength of composited structural B-C-W members. These B-C-W members, defined as concrete-filled steel box beams, columns and shear walls, consist of a slender rectangular steel plate box filled with concrete and inserted steel plates connecting the two long-side steel plates. These structural elements are intended to be used in structural members of super-tall buildings and nuclear safety-related structures. The concrete confined by the steel plate acts to be in a multi-axial stressed state: therefore, its shear strength was calculated on the basis of a concrete\'s failure criterion model. The shear strength of the steel plates on the long sides of the structural element was computed using the von Mises plastic strength theory without taking into account the buckling of the steel plate. The spacing and strength of the inserted plates to induce plate yielding before buckling was determined using elastic plate theory. Therefore, a predictive method to compute the shear strength of composited structural B-C-W members without considering the shear span ratio was obtained. A coefficient considering the influence of the shear span ratio was introduced into the formula to compute the anti-lateral bearing capacity of composited structural B-C-W members. Comparisons were made between the numerical results and the test results along with this method to predict the anti-lateral bearing capacity of concrete-filled steel box walls. Nonlinear static analysis of concrete-filled steel box walls was also conducted by using ABAQUS and the results agreed well with the experimental data.

Numerical study of hydrogen-air combustion characteristics in a novel micro-thermophotovoltaic power generator

In the present work, a micro combustor for thermophotovoltaic (TPV) devices is proposed which is included a U-shaped microtube in a box with a secondary fluid in space between U-shaped microtube and box walls. By utilizing the three-dimensional CFD model, combustion characteristics of the premixed lean hydrogen-air mixture in the present micro combustor are studied numerically with detailed chemistry and transport taking into account heat transfer through the wall. The results show that the establishment of secondary flows and better preheating in the curved tubes is caused the flammability limits to be at least four times in comparison with straight tubes. Combustion characteristics are studied for different parameters, namely inlet velocity, wall thermal conductivity, heat loss conditions, tube curvature and number of U-shaped tubes. By increasing inlet velocity up to 16m/s, flame front moves toward downstream, the maximum temperature is increased and rate of reactions is intensified. The highest efficiency for thermophotovoltaic devices is calculated at 4m/s inlet velocity. A wall thermal conductivity of 3W/m K creates a better condition for flame stability. It is shown that the secondary fluid with higher thermal diffusivity could improve combustion characteristics. Energy conversion efficiency (ηQ), emitter efficiency (ηRad) and total energy conversion efficiency of the TPV (ηtotal) is utilized to investigate the simulated cases for the present geometry. This type of micro combustor is well fitted for thermophotovoltaic applications.

Subjective listening tests: Perception and preference of simulated sound fields

Concert hall sound fields were simulated by architecture students and anechoic recordings were convolved to create auralizations in those simulated performance spaces. Then an architectural feature was altered digitally and a second track was auralized. College music students were recruited, tested for hearing loss, and brought to a low-reverberance room with a spatial sound array of 28 mounted speakers. They were asked to identify which of the two simulated tracks they prefer. We compared simulated performance spaces: (1) with four tiers of balconies vs with one tier of balcony; (2) with an over-stage canopy vs without a canopy; (3) with separate balcony boxes vs with a continuous balcony not fragmented by box walls; and (4) with a higher scattering coefficient vs a lower scattering coefficient. Those in the audience will be invited to judge preference between the tracks for themselves. The study will be framed by the extraordinary career arc of Bert Kinzey who engaged architecture students in the study of architectural acoustics at both Virginia Tech and at the University of Florida.

ConvNet-Based Localization of Anatomical Structures in 3-D Medical Images.

Localization of anatomical structures is a prerequisite for many tasks in a medical image analysis. We propose a method for automatic localization of one or more anatomical structures in 3-D medical images through detection of their presence in 2-D image slices using a convolutional neural network (ConvNet). A single ConvNet is trained to detect the presence of the anatomical structure of interest in axial, coronal, and sagittal slices extracted from a 3-D image. To allow the ConvNet to analyze slices of different sizes, spatial pyramid pooling is applied. After detection, 3-D bounding boxes are created by combining the output of the ConvNet in all slices. In the experiments, 200 chest CT, 100 cardiac CT angiography (CTA), and 100 abdomen CT scans were used. The heart, ascending aorta, aortic arch, and descending aorta were localized in chest CT scans, the left cardiac ventricle in cardiac CTA scans, and the liver in abdomen CT scans. Localization was evaluated using the distances between automatically and manually defined reference bounding box centroids and walls. The best results were achieved in the localization of structures with clearly defined boundaries (e.g., aortic arch) and the worst when the structure boundary was not clearly visible (e.g., liver). The method was more robust and accurate in localization multiple structures.

Experimental Study on Melting and Solidification of Phase Change Material Thermal Storage

Melting and solidification process of Phase Change Materials (PCMs) are investigated experimentally. The tested PCMs are Paraffin wax and Steric acid which typically used for solar water heater. The objective is to explore the characteristics of the PCM when it is being melted and solidified. The experiments are performed in a glass box. One side of the box wall is heated while the opposite wall is kept constant and other walls are insulated. Temperature of the heated wall are kept constant at 80°C, 85°C, and 90°C, respectively. Every experiment is carried out for 600 minutes. Temperatures are recorded and the melting and solidification processes are pictured by using camera. The results show that the melting process starts from the upper part of the thermal storage. In the solidification process, it starts from the lower part of the thermal storage. As a thermal energy storage, Paraffin wax is better than Steric acid. This is because Paraffin wax can store more energy. At heat source temperature of 90°C, thermal energy stored by Paraffin wax and Stearic acid is 61.84 kJ and 57.39 kJ, respectively. Thus it is better to used Paraffin wax in the solar water heater as thermal energy storage.

Exact solution of the Fokker-Planck equation for isotropic scattering

An analytic solution for a Fokker-Planck equation that describes propagation of energetic particles through a scattering medium is obtained. The solution is found in terms of an infinite series of mixed moments of particle distribution. The spatial dispersion of a particle cloud released at t=0 evolves through three phases, ballistic (t<Tc), transdiffusive (t~Tc) and diffusive (t>>Tc), where Tc is the collision time.The ballistic phase is characterized by a decelerating expansion of the initial point source in form of a "box" distribution with thickening walls. The next, transdiffusive phase is marked by the box walls thickened to its size and a noticeable slow down of expansion. Finally, the evolution enters the conventional diffusion phase.

Estructura de la estación intermodal Bir Mourad Raïs (Argel)

In this article the most significant features of the Bir Mourad Raïs Intermodal Station, in Algiers, are described, as well as the most important aspects of the structural design and the characteristics of the analysis, in particular those corresponding to the consideration of the seismic action. Eventually the dimensioning of concrete elements, especially box and sheet walls, is explained, establishing the ductility requirements and the calculations performed to verify its fulfillment.

Statistical considerations on stationary-random noise propagating through a solid medium

In this paper the noise propagation through a solid medium is considered to study how the parameters of the statistical model change. In particular the external and internal sound fields of a box are taken into account. It is experimentally shown that the variance of the real and the imaginary parts of the external stationary random noise change differently while going through the box walls. The generalized Rayleigh distribution is shown to be more suitable to model the noise inside the cavity instead of the classical Rayleigh distribution. Starting from this outcome it has been studied how this noise affects a signal. It is known that a signal modulus affected by stationary random noise can be described by using the Rice distribution if the real and imaginary parts of the noise are statistically independent and identically distributed with zero mean and equal variances. Otherwise the less popular generalized Rice distribution must be used. The main differences of using the Rice or the generalized Rice distributions are shown by considering phasors both with constant and variable phases. In this paper it is shown that the bias estimation depends on the phase of the phasor if the variances of the real and imaginary parts are different and a numerical quantification is given. The attained results are useful when performing measurements of the sound pressure field due to a sound source inside a cavity affected by external noise.