Bottom Box Research Articles

Structural analysis and optimal design of a spherical thin-walled stainless steel water tank without reinforced tie ribs

A spherical thin-walled stainless steel water tank without reinforced tie ribs has been designed to address the issues of easy fracture and corrosion of the ribs, difficulty in maintenance and cleaning, and short service life exposed during the use of thin-walled stainless steel water tanks with reinforced tie ribs. Firstly, an analytical model of a flat steel thin-walled water tank without reinforced tie ribs was established and subjected to static analysis under water pressure. The deformation and stress distribution patterns of the side molded plate of the flat box were obtained. Secondly, a spherical non ribbed thin-walled stainless steel water tank structure was designed with circular cross-section under different box bulge parameters, and its mechanical response characteristics under water pressure load were analyzed. A strengthening scheme was designed for the bottom box molded plate. Once again, optimize the combination design of the box scheme and the reinforcement scheme, and analyze their static, thermodynamic, and thermal solid coupling performance. Finally, the Latin Hypercube Sampling method was used to generate experimental design samples, and a response surface approximation model of a spherical thin-walled stainless steel water tank without reinforced tie ribs was constructed. The wall thickness of the box molded plate, skeleton, and reinforcement were used as design variables, and the maximum deformation and maximum equivalent stress were used as constraints. The lightweight design was carried out with the goal of minimizing mass. The research results indicate that the design program and parameter selection method for spherical thin-walled stainless steel water tanks without reinforced tie ribs proposed in the article are efficient and feasible, and can provide technical reference and theoretical support for the layout and overall optimization design of non ribbed thin-walled stainless steel water tank structures.

Double Plane Direct Shear Apparatus for Determination of Adhesion Factor in Clays

Abstract A modified direct shear assembly with two parallel shear planes was designed to enable the simultaneous and independent measurement of cohesive and adhesive resistance; it is named the “double-plane direct shear device.” The three-block specimen box of the device has top and middle blocks filled with soil specimen and the bottom block is made of solid steel. The middle box is laterally displaced while restraining the top and bottom box, leading to concurrent shearing along two parallel shear planes. Results from quick undrained testing of kaolinite at five different consistency indexes (Ic) and three different vertical stresses (σv) are presented. The stress–deformation curves show greater mobilization of adhesive stress than cohesive stress at low deformations at all Ic and σv. The deformation required for the complete mobilization of cohesive and adhesive stresses and their variation with Ic and σv is discussed. A parameter crossover deformation (dco) is defined to identify the region where adhesive stress is greater than cohesive stress, which would be useful in applications where soil stickiness is of concern. The results show that the presence of partial drainage increases the dco, which results in an increased deformation range over which adhesive stress is greater than cohesive stress, thereby increasing the stickiness susceptibility. Furthermore, results show that the adhesion factor (α, defined as the ratio of adhesion to undrained cohesion) always stayed below unity under undrained conditions, whereas under partial drainage conditions, values of α greater than unity were obtained. The study concludes that for the application where soil stickiness is of concern, the determination of α and its usage to analyze stickiness susceptibility should be performed under simulation of appropriate drainage boundary conditions.

Investigation of Shear Strength of Subbase-Subgrade Interface with Geosynthetics Reinforcement Utilizing A Large-Scale Direct Shear Test

Geosynthetics are being used to strengthen road pavement. Geosynthetic inclusions improve pavement carrying capacity, maintenance costs, highway service life, reflective cracks, and undesirable large lateral and vertical deformations. The primary purpose of this research is to determine the effectiveness of geosynthetics (geogrids and geotextiles) in stabilizing the subgrade and reinforcing the base course layers in unpaved test sections. Determine the mechanical interaction of subgrade soils (clay and sand) and aggregate road base layers (subbase) with and without reinforcement. Compute the shear strength parameters (cohesion, friction angle, and interface coefficient factor). Therefore, Large-scale direct shear experiments in the laboratory were performed on subbase-subgrade materials with and without geosynthetics, under the applying normal of stresses (25, 50, 75, and 100) kPa, indicating the quantity overburden the pressure in paving. The present research uses a large-scale direct shear apparatus with an up square box (200 mm×200 mm×100 mm) and a bottom rectangular box (200 mm×250 mm×100 mm). A direct shear test was implemented by manufacturing this equipment. The results obtained from experiments showed that biaxial geogrid G1 has the best behavior for both (subbase-clay) and (subbase-sand) and has an interface shear coefficient factor more significant than unity and equal to 1.05 and 1.02, respectively.

Behavior of axially loaded L-shaped RC columns strengthened using steel jacketing

Other than rectangular and circular columns, the most commonly used sections in reinforced concrete (RC) buildings in Saudi Arabia are L-shaped columns with a re-entrant angle of 90° or more. The structural designers are using L-shaped columns to meet the architectural and functional constraints of the building without obstructing the movement. Strengthening of such L-shaped RC columns is required to increase their load capacity for a number of reasons, such as an increase in the number of stories, the change of building use, design error(s), or construction defect(s). This research studied experimentally and analytically the behavior of strengthened L-shaped RC columns. The test matrix comprised two groups of six half-scale L-shaped RC columns. In the first and second groups, respectively, columns had 90° and 135° re-entrant corners. Each group had three columns: one unstrengthened control specimen used as a baseline for comparison and two steel-jacketed columns. In the first strengthened specimen, there was a 25 mm gap at the interface of the steel jacket with the ends (bottom base and top box), whereas, in the second specimen, the jacket was connected with the ends. The column specimens were concentrically loaded in compression until failure. It is demonstrated that strengthening of L-shaped columns with disconnected steel jackets had limited improvement in the axial load capacity ranging from 26% to 29% over the unstrengthened ones, while upgrading the columns with connected steel jackets had major enhancement in the axial load capacity varying from 68% to 79% over the control specimens. Furthermore, an analytical model that considers concrete confinement and axial load contributed by connected steel jacket was developed for assessing the axial capacity of tested specimens. Good agreement was achieved between the experimental and analytical peak loads with errors in prediction ranging from 1% to 6%.

Why Are Psychiatrists Hesitant to Refer Patients For Interventional Treatments?

Why Are Psychiatrists Hesitant to Refer Patients For Interventional Treatments?

The influence of saturation on the interface shear strength of clay and nonwoven geotextile

The paper presents a series of modified direct shear tests to investigate the interface shear strength between clay and nonwoven geotextile under different normal stresses and degrees of saturation. The modified direct shear apparatus consists of a 60 mm × 60 mm square shear box assembly with a 60 mm × 60 mm acrylic block inserted in the bottom shear box. A woven geotextile layer was glued to the top of the acrylic block, while the top shear box was filled by the compacted clayey soil. The results revealed that the interface shear strength of clay and nonwoven geotextile reduced by 13.4-27.7% when changing from optimum moisture content (OMC) of the soil to saturation condition. The high permeability of nonwoven geotextile induced the dissipation of excess pore water pressure at the interface when shearing. As a result, the adhesion factor of the clay-geotextile interface increased from about 0.6 for the specimens at OMC to over 0.8 for consolidated saturated specimens. In contrast, for the impermeable reinforcement, the interface shear strength analysis of previous studies shows that the adhesion factor of the reinforcement and clayey soil would be reduced when increasing the water content of the clay specimens.
 Keywords:
 adhesion factor; clay; nonwoven geotextile, interface shear strength; saturation.

Clinical risk factors in SUDEP: A nationwide population-based case-control study.

In the article “Clinical risk factors in SUDEP: A nationwide population-based case-control study” by Sveinsson et al.,1 the bottom box in figure 1 should read “n = 255” and the fifth box down on the right should read “Controls.” The editorial staff regret the errors.

Design of Sustainable PV Module for Efficient Power Generation During Faults

The design of a sustainable photovoltaic (PV) module with advantages of high power output during faulty and hot-spot conditions is presented. This PV module is designed by incorporating a small modification in the existing PV modules. The cost involved in modification is negligible during the initial fabrication process. In a commercial market, all PV modules have only one junction box that contains terminals from various strings. Bypass diodes and output cables are connected with these terminals in the junction box. In the existing PV module, two substrings are connected in series, and its output terminals are given to the junction box. The proposed PV module has two junction boxes: one at the top and another at the bottom. The top box has top-end terminals of each substring, whereas the bottom box has bottom-end terminals of each substring. By having two junction boxes, the proposed PV module provides an opportunity to remodify the string connections during fault conditions. This research work analyzed the performance of existing and proposed PV modules under faulty and hot-spot conditions. This analysis verifies the sustainable nature of the proposed PV module.

Experimental Studies on Thermo-mechanical Coupled Behavior of Pile-Clay Interface

The thermo-mechanical coupled behavior of pile-soil interface is very important for the mechanical performance of energy pile. It is studied in this paper by the thermo-mechanical coupled direct shear tests with a temperature controllable concrete specimen in the top shear box and a Kaolin clay specimen in the bottom shear box. The results show that the strength of pile-clay interface significantly depends on the temperature, the temperature cycle number and the over-consolidation ratios of clay. With the heating-cooling cycles, the interface strength can increase and decrease monotonically or non-monotonically depending on the stress state and history of clay, which is generally a thermo-elasto-plastic process. It is shown that the thermo-mechanical coupled pile-clay interface behavior is the net effect of the pore water transportation and the rearrangement of clay particles near the interface as well as the thermal consolidation/expansion of clay.

Investigation of effects of temperature cycles on soil-concrete interface behavior using direct shear tests

The intermittent operation of the ground source heat pump connected to thermo-active geo-structures (e.g. energy piles) results in cyclic thermal loading on the soil-structure interface. To investigate the effects of cyclic thermal loading on soil-structure interface properties, a conventional direct shear device was modified by replacing the bottom shear box with a concrete plate (with smooth and rough surfaces) that has embedded aluminum tubes to heat and cool the interface. A series of tests were performed with interface temperatures of 4.5, 22.5, and 42.5 °C, respectively. The constant normal stresses of the direct shear tests were 27.6, 41.4, and 100 kPa. The tests were conducted both under cooling and heating conditions with thermal cycle numbers of 0.5 and 10.5. The tests were conducted at a shearing rate of 3 mm/min. The effects of water content changes on the shear strength of soil-concrete interface was also investigated by performing tests with soil water content ranging from 15% to 19%. The responses of soil-concrete interface subjected to temperature change and cycles and different water contents are presented in this paper.

Numerical simulation of partially filled liquid containers with special type bottom geometry under earthquake excitation

Numerical simulation of liquid in partially filled tank of flat bottom and bottom box shape is investigated in the present paper. Previously, dynamic response of flat bottom tank has been carried out numerously, but the dynamic response of bottom box tank remains unclear. Therefor a parametric study on bottom box shape tank is carried out to understand the dynamic response of contained liquid under both harmonic excitation and real earthquake excitation. The efficacy of the present numerical model is verified by comparing the results with the published results. Galerkin’s finite element method is used to derive the modal equations of motion for sloshing. The slosh wave displacement, hydrodynamic pressure distribution and the base shear, are quantified for the bottom box shape tank. According to the dynamic analysis results larger size of bottom box significantly reduces the effective mass of liquid which keeps the container on safer side than the flat bottom container.

Water Content–Density Criteria for Determining Geomembrane–Fly Ash Interface Shear Strength

The aim of the present paper was to determine shear strength at the interface between fly ash, as a material underlying artificial sealing layer of storage yards, and HDPE geomembranes. The fly ash was compacted at moisture contents ranging over optimum water contents ± 5% using the standard Proctor test. The shear strength and interaction tests were conducted in classic direct shear apparatus with a cylindrical shear box. For interface strength tests the bottom box frame was equipped with a polycarbonate platen, which enabled geomembrane fixing. The shear strength of the interface contact of fly ash–smooth HDPE geomembrane did not greatly depend on moisture at compaction; however, it was important for textured geomembrane. The lowest interface strength was obtained at the highest moisture w= wopt + 5%, and the greatest values at moistures w ≥ wopt, for both geomembranes.

Characterization and control of “bottom box water spot”, a new citrus rind disorder in Spain

Characterization and control of “bottom box water spot”, a new citrus rind disorder in Spain

Dustproof cooling of the electrical box

In present are electrical boxes cooled by air through the intake hole on the bottom electrical box to the box space with electrotechnical elements and exhaust through the hole at the top to the surrounding by natural convection. This cooling method is effective but operate with the risk of contamination electrotechnical elements by dust sucking from surrounding air. The goal of this work is solution of the dustproof cooling of the electrical box by natural convection. The work deal with design of the device with the heat transfer by the phase change of the working fluid and experimental measuring its thermal performance at the cooling electrotechnical elements loaded by heat 1 200 W in the dustproof electrical box.

(Invited) Sequential 3D Process Integration: Opportunities for Low Temperature Processing

3D sequential integration of two stacked transistor levels has been recently demonstrated with success on 300 mm wafers with a maximum thermal budget approaching 650°C-20 minutes for the completion of the top level [1]. However, such thermal budget is still too high to avoid any degradation of the bottom transistors performance [2]. Thus, for several technological modules, such as dopant activation, gate stack formation, spacers deposition and source/ drain epitaxy, very low temperature processes must be developed. For low temperature junction activation, solid phase epitaxy regrowth (SPER) is a first option, with typical annealing conditions around 600°C-1 minute [1]. Sub-microsecond laser annealing is a second approach, with the capability to selectively heat a sub-µm surface region. In this paper, we review recent advances in UV pulsed laser annealing in view of 3D sequential integration. Based on 2D numerical simulations, we optimized the process structure for the upper source and drain activation and recrystallization upon laser annealing (wavelength: 308 nm), while trying to avoid any degradation of the bottom transistor. An anti-reflective capping layer over the top transistors is found to reduce laser energy absorption in the upper gate (Figure 1). The lower gate maximum temperature can be reduced down to 600°C (pulse duration: 160 ns) with a structure combining favorable bottom BOX and inter-level SiO2 thicknesses (Figure 2). Moreover, with a shorter laser pulse (80 ns), the bottom level temperature can even approach 500°C while the upper level layers reach 1200°C. To mimic the optimal structures with simple vehicle tests and evaluate the laser annealing process window for dopant activation, SOI structures (25 nm BOX, 23 nm top Si layer) have been implanted with As, BF2 or P, then capped with 30 nm SiN and annealed using SCREEN-LASSE LT-3100 system at various laser energy densities. Sheet resistance measurements combined with SIMS profiles and TEM cross-section observations (Figure 3) allowed us to identify the different regimes encountered as a function of the laser fluence. The process window starts when the whole region amorphized by implantation on top of the single crystalline thin seed layer is melt, and stops with the full SOI layer melt. Around the optimal energy density, we reached perfect crystal recovery and high dopant activation levels, comparable to those obtained with spike RTP. Concerning the laser pulse duration, a trade-off is to be found: The process window is reasonably large in case of a 160 ns pulse and becomes narrower with a 80 ns pulse but such shorter laser treatment is more favorable in terms of heat diffusion. To avoid global routing congestion, the 3D sequential architecture requires the introduction of inter-tier Back-End-Of-line (iBEOL) levels routing the bottom tier. As a consequence, such iBEOL needs to support the thermal budget applied for the top tier processing. Coupling numerical simulations with experimental tests on simplified structures, we investigated the impact of pulsed laser annealing on such inter-level metal interconnection. Based on 28 nm standard design rules, we integrated one metal level (Cu) using porous SiOCH as ultra-low-k dielectric and the appropriate barrier layers. Before submitting such structures to laser annealing, we deposited 50 nm or 120 nm inter-level SiO2 and 20 nm amorphous Si (a-Si) to simulate the top transistor level. According to simulations, above relaxed interconnect regions (large interconnect pitch), the average thermal conductivity of the stack is lower, promoting a slightly faster temperature rise in these regions, compared to more dense regions. A thicker inter-level oxide layer contributes to reduce the peak temperature of the Cu interconnects. Finally, line resistance and lateral capacitance measurements show no modification upon laser annealing, even with conditions leading to the melt of the top a-Si layer, for both 50 and 120 nm inter-level oxides (Figure 4). All these results provide guidelines for low temperature junction formation in a 3D sequential integration using nanosecond laser annealing, reinforcing this technique as a true alternative to SPER.

Remembering the Slide Rule [Back to Basics

Languishing in the bottom drawer or memento box of many mature engineers and scientists is an instrument that helped produce the smallest to the most complex designs for hundreds of years. The Slide Rule, once carried by many of us on our belt or prominently displayed on a pile of books to let the world know that we were “techies,” was the “calculator” for generations of designers. As with many technologies it became obsolete suddenly and in a matter of a few years was relegated to history, but more about that later.

Dynamic Performance of Stacked Packaging Units

Stacked packaging units is the main form of distribution packaging of products. Its dynamic performance is not fully understood. This paper investigated the influence of the constraint, input vibration, location and contact nonlinearity on the dynamic performance of three layers stacked packaging units. The dynamic contact force between surfaces and acceleration response of products were obtained. In sine sweep vibrations, the constraint to stacked packaging units has an obvious influence on the dynamic characteristics. The acceleration response of product is associated with the vibration mode. The force amplification factor is in general between 1.5 and 2, but it can close to 3 on top layer in the case of no fixed. In random vibrations, non‐Gaussian data of dynamic contact force appear when Gaussian data of input vibration pass through the stacked packaging units, resulting a Weibull distribution of force level‐crossing. The force level‐crossing diagram becomes more abrupt with the decreasing of input vibration level, smoother from the top contact surface to middle and bottom ones, and moves right and becomes smoother with the constraint strengthen. In the case of lower input level, Gaussian distribution of force level‐crossing appears. The force power spectral density (PSD) between bottom box and table is much larger than that between boxes, which is significantly influenced by the first resonance frequency. However, the acceleration PSD of product is significantly influenced by both the first and second resonance frequencies, and controlled by the vibration mode. It depends much on the value of input acceleration PSD around the resonance frequencies.

Errata: Vol. 65, No. 20.

In the MMWR report, "Fatal Abusive Head Trauma Among Children Aged <5 Years - United States, 1999-2014," multiple errors occurred in the figure on page 507 (corrected text is noted by underline). The top box should have read, "The underlying cause code in the death record must indicate assault as the intent of injury." The bottom left box should have read, "Abusive head trauma diagnosis codes (S02.0-S02.1, S02.7-S02.9, S04.0, S06.0-S06.9, S07.1, S07.8-S07.9, S09.7-S09.8, T90.2, T90.5, T90.8-T90.9)." The bottom right box should have read, "Must exclude all abusive head trauma injury codes," and "Must exclude all of these traumatic brain injury diagnosis codes."

Angiotensin-II, the Brain, and Hypertension: An Update.

Despite enormous therapeutic advancements, the incidence of hypertension continues to rise1 and remains a medical burden of global proportions.2 This is likely due, in part, to the complex pathogenesis of hypertension.1 In addition to pathological processes in peripheral cardiovascular organs, the central nervous system (CNS) has emerged as a major culprit. The renin–angiotensin system (RAS) plays a crucial role in cardiovascular control, and both systemic angiotensin-II (Ang-II) and centrally generated Ang-II signal through complex neural networks to contribute to the development of hypertension (Figure). Although the effects of Ang-II within the brain are multifaceted, several key hypertensive players have emerged, including oxidative stress, endoplasmic reticulum stress, inflammation, and transcription factor activation. The purpose of this review is to provide a brief update on recent work related to Ang-II, the brain, and hypertension with a specific focus on Hypertension articles when appropriate. Figure. Simplified schematic illustrating the signaling pathways ( top box), as well as neural networks and sympathetic nervous system influenced physiological outputs ( middle box) involved in the development of hypertension due to peripherally or locally generated angiotensin-II (Ang-II) action in the brain. Common animal models used to evaluate Ang-II, the brain, and hypertension are also highlighted ( bottom box). See text for additional details. AP indicates area postrema; AP-1, activator protein-1; AT1aR, angiotensin type 1a receptor; CVLM, caudal ventral lateral medulla; DOCA, deoxycorticosterone acetate; ER, endoplasmic reticulum; EP1R, prostaglandin E receptor 1; IML, intermediolateral nucleus; MnPO, median preoptic nucleus; NAD(P)H, nicotinamide adenine dinucleotide phosphate; NTS, nucleus tractus solitarii; NF-κB, nuclear factor-κB; OVLT, organum vasculosum lamina terminalis; PP, posterior pituitary; PVN, paraventricular nucleus of the hypothalamus; ROS, reactive oxygen species; RVLM, rostral ventral lateral medulla; SFO, subfornical organ; SHR, spontaneously hypertensive rat; and SON, supraoptic nucleus. Dysregulation of the RAS is common in human hypertension,3 …

The Vertical Spatial Metaphor of Moral Concepts and Its Influence on Cognition

Three studies investigate the vertical spatial metaphor of moral concepts and its influence on cognition. Study 1 was a paper-pencil forced-choice task in which participants saw a cartoon character and two square boxes (one above and one below the character), and were asked to place moral and immoral words into the top or the bottom box of their own will. A matching effect appeared both between the moral terms and the above/up space, and between the immoral terms and the below/down space. Study 2 was a computerized categorization task carried out in E-prime. Participants were instructed to categorize words according to whether they were positive or negative in meaning as quickly and accurately as possible. Response times were shorter when moral words appeared at the top of the screen, and when immoral words appeared at the bottom. Study 3 employed a implicit priming task in which participants first memorized moral or immoral concepts and then estimated the height of objects. concepts led to height overestimation while immoral ones led to underestimation. All together, the results suggest that, for Chinese language, there is psychological reality of Moral is up, immoral is down. Such a spatial representation of Chinese moral concepts exists at both the conscious and the subconscious level. Other cognitive activities can be influenced by the spatial metaphor of moral concepts subtly. And this new effect is called the Cognitive Deviation Effect of Chinese Concepts’ Metaphorical Representation.