Bottom Surface Area Research Articles

Construction of porous diamond film with enhanced electric double-layer capacitance via regrowth of diamond nanoplatelets

The engineering of porous boron-doped diamond (BDD) film has sparked significant interest in improving electric double-layer (EDL) capacitance. However, the presence of disordered and tortuous pores in the BDD film hinders the accessibility of the bottom pore surface area, leading to a decrease in specific EDL capacitance. Herein, a novel porous BDD film with vertically open pore channels is constructed through the overcoating of diamond nanoplatelet template with a BDD layer using chemical vapor deposition. Electrochemical investigations manifest that the specific areal EDL capacitance of the porous BDD is ∼428 times greater than that of the planar BDD film. More impressively, the porous BDD film demonstrates a higher specific volumetric EDL capacitance (39.30 F/cm3) and superior long-term stability (100% capacitance retention after 12,000 cycles), surpassing the performance of most developed porous BDD electrodes. The exceptional performance of the porous BDD film was attributed to the abundant vertically open pore channels, good hydrophilic property, maximized electrochemical available area, and good chemical/mechanical stability. This work benefits the development of the BDD film as an EDL micro-capacitor electrode, and the methodology proposed here shows great potentials to fabricate an ordered porous BDD nanostructure with large specific area for more electrochemical applications.

Potential energy savings of air lubrication technology on merchant ships

As the reduction of greenhouse gas emissions has become an important issue, measures and devices to reduce energy consumption are in increasing demand. In this study, the potential energy saving due to the application of air lubrication technology in merchant ships is analyzed. We propose a simplified empirical model, covering three different air lubrication technologies, based on the experimental results and assumptions taken in the existing studies. The bottom surface area covered with air is important for the efficiency of the air lubrication system, according to the sensitivity analysis. From the global fleet analysis, net-percentage power saving varies according to the operational profile as well as the technology. Net-percentage power savings of 2–5% from air bubble, 8–14% from air layer, and 16–22% from air cavity technology were obtained assuming calm-water conditions. The methodology can be adopted in early design stage and fleet-wide analyses of various energy-saving measures.

Potential of storm water storage tank outflow construction in the prevention of sewerage overload

The impact of a storm water storage tank outflow construction on its required volume is discussed. A dimensioning of the tank by a rational method applied for small sewerage systems is presented. For large systems, subroutines should be developed to take into consideration the construction details of complex storage tanks in the software enabling real time modelling of sewerage systems. Such subroutines can be tested under simple conditions using rational methods of sewerage modelling, including the approach described in the paper. In the example discussed here for two different positions of the sewer delivering to and collecting stormwater out of the tank both the tank required volume and the outflow as a function of time visibly depended on the sewer position. This was proofed for a rectangular chamber storage tank of the same bottom surface area. However, if the bottom surface area and the storage tank height were calculated in such a way to enable the same maximum value of an outflow from the tank for two different positions of the sewer both the tank volume and the outflow as a function of time were proved to be very similar. Concluding the tank volume depends visibly on the construction of outflow, but the height of the tank can be adjusted in such a way to keep the same maximum outflow for different details of the outflow construction. After this adjustment, the volume of the tank was proved to be almost independent of the construction of outflow from the tank.

Similar Carcass Surface Microbiota Observed Following Primary Processing of Different Pig Batches.

Bacterial contamination during meat processing is a concern for both food safety and for the shelf life of pork meat products. The gut microbiota of meat-producing animals is one of the most important sources of surface contamination of processed carcasses. This microbiota is recognized to vary between pigs from different farms and could thus be reflected on the bacterial contamination of carcasses at time of processing. In this study, the microbiota of 26 carcasses of pigs originating from different farms (i.e., batches) were compared to determine if an association could be observed between carcass surface microbiota (top and bottom) and the origin of slaughtered animals. The microbiota of the top and bottom carcass surface areas was analyzed by culturing classical indicator microorganisms (mesophilic aerobic bacteria, Enterobacteria, Escherichia coli, Pseudomonas, and lactic bacteria), by the detection of Salmonella, and by 16S rRNA gene sequencing. Culture results showed higher Enterobacteria, E. coli, and lactic bacteria counts for the bottom areas of the carcasses (neck/chest/shoulder) when compared to the top areas. Salmonella was not detected in any samples. Globally, 16S rRNA gene sequencing showed a similar composition and diversity between the top and bottom carcass areas. Despite the presence of some genera associated with fecal contamination such as Terrisporobacter, Escherichia-Shigella, Turicibacter, Clostridium sensustricto1, and Streptococcus on the carcass surface, sequencing analysis suggested that there was no difference between the different batches of samples from the top and bottom areas of the carcasses. The primary processing therefore appears to cause a uniformization of the carcass global surface microbiota, with some specific bacteria being different depending on the carcass area sampled.

Unconstrained melting of phase change material in cylindrical containers inside hot water tanks: Numerical investigation and effect of aspect ratios

In this study, a numerical model with variable mushy zone constants was developed based on the enthalpy-porosity method for the unconstrained melting of phase change material (PCM) encapsulated in cylindrical containers inside hot water tanks. In particular, a method for dynamically determining mushy zone constants was established. Mushy zone constants were explicitly calculated for each element in the solid region and updated at each iteration in the solution procedure of the model. The model showed satisfactory performance, with a mean absolute relative error of 5.2% between experimental measurements and numerical results. Based on this model, the unconstrained melting process of PCM and the influence of the aspect ratio of the cylindrical container were investigated. Results showed that contact melting accelerated the heat transfer of PCM at the bottom region and further enhanced the natural convection of liquid PCM at the side region. Moreover, the aspect ratio exerted little influence on the heat transfer coefficient at side wall surfaces. The correlation between the total melting time and aspect ratio was also calculated. The peak total melting time occurred for an aspect ratio of 5.49, and the smallest total surface area corresponded to an aspect ratio of 2. Clearly, larger total surface areas do not necessarily result in shorter total melting time. Further analysis indicated that flatter containers likely to be preferable to slenderer containers in practical designs. In addition, increasing the percentage of the bottom surface area to the total surface area can increase the average heat transfer coefficient of latent heat storage units.

Study on the Inter-Electrode Process of Aluminum Electrolysis (Ⅱ)—Digital Analysis of the Anode Gas Distribution Patterns on the Anode Surface Using A See-Through Cell

The evolution behavior of anode gas during aluminum electrolysis has been a hot spot of research for energy saving and process control. In the present work, the bubble evolution behavior during aluminum electrolysis was investigated using a lab-scale see-though cell. The bubble evolution characters on an 11 cm2 (bottom surface area) flat anode, an 11 cm2 slotted anode, and a 50 cm2 flat anode were investigated with statistical analysis, respectively. The results showed that bubbles tended to generate and adhere to certain regions on the anode surface due to the heterogeneity of the carbon material, and the adhering regions moved when current density was increased. The anode slot lowered the actual current density on the anode significantly by reducing the anode bubble coverage. Influenced by the group effect of bubbles, the 50 cm2 flat anode behavior constituted a lower bubble coverage rate, lower average bubble size, and lower actual current density than the 11 cm2 flat anode.

High sensitivity In-Ga-Zn-O nanofiber-based double gate field effect transistors for chemical sensing

Herein, a high sensitivity In-Ga-Zn-O (IGZO) nanofiber channel double gate (DG) field-effect transistor (FET)-based chemical sensor is described. Transparent and flexible IGZO nanofiber channels were fabricated by electrospinning, and IGZO film channels were prepared for comparison via spin coating. We connected a separative extended gate (EG) with a chemical sensing membrane to the fabricated IGZO FETs to test their applicability to pH sensing applications. The effectiveness of the IGZO nanofiber channel was verified by comparing the pH sensitivity and non-ideal effects such as drift and hysteresis voltage with the IGZO film channel. The nanofiber channel showed much higher sensitivity in the dual gate ion-sensitive field-effect transistor (DG ISFET) than the film channel as it has an increased capacitive coupling effect due to an increase in the upper channel surface area and a decreased channel bottom surface area. The sensitivity of the DG ISFET with an IGZO nanofiber channel was 998 mV/pH at room temperature, surpassing the 384 mV/pH of the IGZO film channel, which itself far exceeded the Nernstian limit of 59.16 mV/pH. Furthermore, the nanofiber channel had a lower hysteresis voltage and drift rate compared to its amplified sensitivity, and exhibited a more stable performance than the film channel. Therefore, IGZO nanofiber-based DG FET chemical sensors are expected to be promising for use in transparent and wearable biosensor applications.

Effects of crayfish density, body size and substrate on consumption of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) eggs by invasive rusty crayfish [(Orconectes rusticus (Girard, 1852)

The density and size of benthic predators such as crayfish and the physical characteristics of aquatic habitats including benthic substrate size have been hypothesized to significantly affect levels of lake sturgeon (Acipenser fulvescens) egg consumption. The invasive rusty crayfish (Orconectes rusticus) was used to quantify consumption and apportion variation in egg loss in an experimental setting. Experiments consisted of large flow-through rectangular tanks (0.8 m wide, 2.96 m2 total bottom surface area) receiving river water to mimic natural diel temperature regimes. Four crayfish densities were tested (5, 10, 15, 30 individuals or 1.7, 3.4, 5.1, 10.1 individuals/m2) that span the range of densities observed in natural settings. Crayfish were allowed to freely move among three substrates commonly found at spawning locations where lake sturgeon eggs are deposited (cobble, gravel and sand). After an acclimation period (15 min), 200 lake sturgeon eggs were randomly scattered over each substrate category (600 eggs per tank). Mean (± SE) egg consumption over 48 hr was 80 ± 3% (range 19–100% across 16 replicate trials). Egg consumption increased significantly as a function of increasing crayfish density. The effect of substrate size, however, depended significantly on crayfish density (substrate size × predator density interaction). Egg consumption significantly increased as substrate size decreased (e.g. from gravel to sand), at both high and low crayfish densities. Egg consumption also increased with increasing mean crayfish body size. Our results revealed that levels of lake sturgeon egg consumption by rusty crayfish are high in some settings. Further work is needed to determine if egg consumption in natural river settings is similarly high and whether egg consumption by crayfish and other egg predators could negatively affect population levels of recruitment.

Dynamic fragmentation of ice spheres: Two specific fracture patterns

Although ice materials are commonly found not only in our daily life on the earth but also in space, e.g. in the rings of Saturn, their fracture mechanisms, especially those in a dynamic range, have not been fully clarified. In our previous investigation, therefore, collision of a brittle ice sphere (diameter 25, 50 or 60 mm) that is free falling against a fixed plate of ice or polycarbonate has been experimentally observed using high-speed digital video cameras at a frame rate of up to 150,000 frames per second. It has been recognized that there exist basically only two specific fracture patterns generated by this dynamic impact: (i) “Top”-type fracture, normally at a relatively smaller impact speed, where only the bottom surface areas of a sphere are fragmented into small pieces by the impact at bottom and a relatively large top-shaped portion is left unbroken; and (ii) “orange segments”-type in which rather flat fracture planes extend approximately along the central axis of the sphere and split the sphere into three or four larger segments of comparable size. Preliminary comparison of the experimental findings with linear elastic wave fields obtained numerically by three-dimensional finite difference calculations suggests two distinct spatiotemporal scales: (1) The “top” fracture pattern is induced by the propagation of surface waves with relatively shorter wavelengths from the bottom along the free surface of the sphere, quickly producing fracture only near the bottom; (2) In the “orange segments”-type fracture, a longer contact time makes largely stressed regions enlarge more slowly and widely (quasi-statically-like) and larger fracture planes develop along the axis of the sphere. The above speculations seem to be supported by recent computations adopting the Discontinuous Galerkin (DG) method that treat more rigorously the mechanics of dynamic contact between the sphere and plate.

Can in vivo surface dental enamelmicrobiopsies be used to measure remote lead exposure?

Measuring lead in the surface dental enamel (SDE) using biopsies is a rapid, safe, and painless procedure. The dental enamel lead levels (DELLs) decrease from the outermost superficial layer to the inner layer of dental enamel, which becomes crucial for the biopsy depth (BD) measurement. However, whether the origin of lead found in SDE is fully endogenous is not yet established. There is also controversy about the biopsy protocol. The aims of this study were to investigate if DELLs are altered by extrinsic contamination (A) and to evaluate the real geometric figure formed by the erosion provoked by biopsy procedure and the respective BD in SDE (B). To accomplish the aim A, lead from 90 bovine incisor crowns lead was determined by graphite furnace atomic absorption spectrometer as a function of exposure time and lead concentration. Two biopsies were performed in each tooth, before and after lead exposure. Six 15-tooth groups differed by exposure time (1 or 30min) and lead concentrations (A. 0mg/L-placebo, B. 0.01mg/L-standard for drinking water, or C. 0.06mg/L-concentration found in contaminated groundwater). Phosphorus was determined by an inductively coupled plasm optical emission spectrometer to quantify the enamel removed. To compare intakes/losses of lead in SDE among the groups, values of DELL differences between before and after lead exposure were compared by ANOVA (p < 0.05). To attain the objective B, one extracted human permanent tooth was studied by confocal Raman microscopy. Lead measurements and the surface profile were determined. There was no difference in DELL among the groups (p = 0.964). The biopsy bottom surface area, analyzed by microscopy, showed an irregular area, with regions of peaks and valleys, where areas with depth ranging from 0.2 (peaks) to 1.8μm (valleys) (± 0.1μm) could be found. BD carried out in vivo is commonly calculated using the cylinder height formula. The real BD was shown to be very similar to already published data. In conclusion, the SDE of erupted teeth does not seem to be susceptible to environmental lead intake, being thus reliable to measure remote exposures to lead.

Magnetic fixtures for enhancement of smoothing effect by electron beam melting

In large-area electron beam (EB) irradiation method developed recently, high energy density EB can be obtained without focusing the beam. Therefore, large-area EB of 60mm in diameter can be used for instant melting and evaporation of the wide area material surface, and high efficient surface finishing is possible. However, if the workpiece has a hole shape, the EB concentrates in the entrance edge or inside wall of the hole. Thus, it is difficult to smooth the hole bottom surface. Previous study showed that the surface smoothing and micro-deburring effects for non-magnetic workpiece could be improved by setting a magnetic block under the workpiece, since the electrons tend to concentrate the magnetic block along magnetic lines. In this study, smoothing of hole bottom surface was experimentally investigated by setting a magnetic block under a workpiece in large-area EB irradiation. Expansion of smoothing area of the bottom surface was also tried by setting a through hole at the center of the magnetic block. It was clarified that wide area of hole bottom surface could be smoothed by large- area EB irradiation by setting the magnetic block under workpiece. The surface roughness decreased to less than 3.0μmRz at the area of hole bottom surface. When the hole diameter was 20mm and hole depth was less than 40mm, smoothing area of 10mm in diameter was obtained by using the magnetic block. Moreover, the smoothing area was sufficiently expanded by setting a through hole with an appropriate diameter in magnetic block.

Frustum pyramid shape of indium bump to lengthen cycling life of InSb infrared detector

The thermal deformation appearing in indium antimonide infrared focal plane arrays (InSb IRFPAs) subjected to thermal shock tests, will easily incur the fracture of InSb chip, this phenomenon restricts the final yield of InSb IRFPAs. In light of the proposed equivalent method, the three dimensional structural modeling of InSb IRFPAs is developed, and the simulated strain distributions are consistent with the buckling pattern, the shallow groove and the local flatness, appearing on the top surface of InSb IRFPAs at the corresponding regions. After comparing the deformation profiles at different regions, we deduce that the top surface flatness of InSb IRFPAs will be improved with frustum pyramid indium bump arrays, and this deduction is verified by the subsequent simulation results. That is, when the top surface area of indium bump is smaller than its bottom surface area, in this paper, the diameter of indium bump bottom surface is set with 24 μm, the simulated Z-components of strain is uniformly covering the whole top surface of InSb IRFPAs, and the deformation amplitude is decreased slowly with the decreasing top surface area of indium frustum pyramid arrays. These findings are beneficial to further improve the flatness of InSb IRFPAs, correspondingly, to lengthen its temperature cycling life.

A new thermal conductivity model for nanorod-based nanofluids

As a new kind of solid/liquid suspension, nanofluid needs to be further explored since its measured thermal conductivity is significantly greater than the classic prediction when containing specially shaped particles, for instance nanorods. Various thermal conductivity models for spherical or tubular nanoparticles based nanofluid have been proposed, but none is specifically responsible for nanorod-based nanofluids. In this paper, a physical model of a nanorod with an interfacial layer in a fluid medium is split apart in axial and radial direction respectively to build various differential equations. And a new thermal conductivity model for nanorod based nanofluids is developed based on the combination of the analytic solutions of those differential equations. The allocation proportion of heat conduction in axial and radial directions in the present model is depended upon the ratio of the flanking and ends (top and bottom) surface area of the nanorod. Finally, the present model and some classic models are compared with the available experimental data retrieved for thermal conductivity of nanorod based nanofluids. And the comparison results show the present model achieves better precision.

Simulation of Edge Defects Behavior of Slabs in the Sizing Press and Roughing Mill of a Hot Strip Mill

Defects in cast slabs can be developed or reduced during hot rolling depending on size, location and distribution of primary defects, quality of the alloy, as well as rolling parameters. Defects, such as cracks, voids, or inclusions and their behavior in the material during rolling severely affects the final product quality. The aim of this work is to develop a 3D finite element method (FEM) model in order to analyze the behavior of surface defects during the deformation in the sizing press and in the roughing mill during hot rolling. To reach this aim, firstly different FEM models for different ideal (without defects and misalignment) slab geometries, rolled with different reduction steps, are developed and studied. After verifying these ideal models, the defects are implemented in the models and their behaviors during deformation are studied. It could be stated that there is a borderline condition for the surface topography and position in the side of the slab, moving the defect to the top or bottom surface area. Moreover, it could be stated that defects implemented on the surface of the slab remain on the surface and do not move into the slab during sizing in the press and the roughing procedure.

Dynamics analysis and design methodology of roll-resistant hydraulically interconnected suspensions for tri-axle straight trucks

A new hydraulically interconnected suspension (HIS) system is proposed to enhance the roll dynamics of the tri-axle straight trucks. The impedance of the hydraulic system is derived with impedance transfer matrix method, and integrated to establish the equations of motion of the mechanical and hydraulic coupling system. Based on the obtained equations, the additional mode stiffness/damping of the vehicle body and wheel state forces are explicitly described with the physical parameters of the hydraulic system. The obtained results indicate that the proposed HIS system can be able to independently enhance the mode stiffness/damping, in which the additional bounce/pitch and roll/warp mode stiffness are determined by the difference and summation of the top and the corresponding bottom piston surface area, respectively. The mode damping is caused by the direction and roll damper valves, simultaneously. The later valves alter the mode damping like the accumulators change the mode stiffness. The comparison of dynamic responses between the trucks with the conventional suspension and the HIS system shows that the HIS system can effectively suppress the roll motion of the truck body and favorably reduce the warp mode force for the wheel stations. Finally, the loss coefficients of the damper valves are tuned in terms of dimensionless factors to handle the compromising indices based on the dynamic responses.

Topological magnetoelectric effects in thin films of topological insulators

We propose that the topological magneto-electric (ME) effect, a hallmark of topological insulators (TIs), can be realized in thin films of TIs in the $\nu=0$ quantum Hall state under magnetic field or by doping two magnetic ions with opposite signs of exchange coupling. These setups have the advantage compared to previously proposed setups that a uniform configuration of magnetic field or magnetization is sufficient for the realization of the topological ME effect. To verify our proposal, we numerically calculate ME response of TI thin films in the cylinder geometry and that of effective 2D models of surface Dirac fermions. The ME response is shown to converge to the quantized value corresponding to the axion angle $\theta=\pm \pi$ in the limit of the large top and bottom surface area of TI films, where non-topological contributions from the bulk and the side surface are negligible.

Microstructure and Mechanical Properties of 22MnB5 Hot Stamping Part

Microstructure and mechanical properties of different area of 22MnB5 hot stamping part were analysis by experiment. The results show that the maximum tensile strength reaches 1578MPa at bottom surface area, and the elongation is at the region of 8.5~12 with die cooling area, and the area of bottom surface has higher tensile strength than that of side wall area. Martensite is formed with die cooling, and tempered martensite and undissolved ferrites were found at side wall area. The microstructure of area with air cooling is composed of ferrite and pearlite, and a small amount of martensite.

The phase separation in a rectangular microchannel by micro-membrane

A phase separator was formed by populating an enclosed micro-membrane at the microchannel center. When a bubble train in the bare duct interacted with the micro-membrane, a single bubble was separated into two daughter bubbles to flow in the two side regions. The separated bubbles never entered the micro-membrane inside due to the increased surfaced energy. A multiscale numerical scheme using the Volume of Fluid (VOF) method tracked the gas–liquid interface. The results identified that the separator consisted of a phase separating section and a fully phase separation section. Within the separating section, the two side regions contained confined bubble train flow. The liquid plugs were gradually shortened along the flow direction, caused by liquid flowing towards the micro-membrane inside. Liquid circulations were observed within liquid plugs. The gas–liquid could be fully separated. Within the fully phase separation section, gas was flowing in the side regions, with ultra-thin liquid films on solid walls. The separator had the potential to be used as a condenser. The heat transfer enhancement is related to Ar (the bubble project area relative to the bottom surface area) and an averaged liquid film thickness. In contrast to the bare duct section, the fully phase separation section significantly increased Ar and decreased liquid film thicknesses. The heat transfer intensity in the fully separated flow section can be ten times of that in the bare duct section.

Holding wild caught red king crab, Paralithodes camtschaticus: effects of stocking density and feeding on survival and meat content

In this study, the effects of different stocking densities on survival, injury and meat content of captive male red king crab (mean weight = 2.6 kg) were examined. The first experiment was carried out in square plastic tanks with stocking densities of 100, 150 and 200 kg m−3 for 56 days. In a second experiment, king crabs were kept at a stocking density of 60 kg m−3 and were either fed or not fed. Both mortality and occurrence of injuries increased significantly with increasing stocking density. In the highest density groups, mortality and frequency of injury was 17% and 14% respectively, compared with 5% and 4% in the 150 kg m−3 group. The percentage meat content was significantly lower at the final census compared with the initial census in all stocking density groups. In Experiment 2, there were no mortalities or injuries in either the fed or unfed treatments. The average percentage meat content increased in the fed treatment and decreased in the starved treatments. The results show that adult male king crab can maintain high survival rates at stocking densities up to 150 kg m−3 in holding facilities of the design used in the present study for periods up to 2 months. However, to reduce mortality and frequency of injury over this period densities as low as 60 kg m−3 and a holding system with a large bottom surface area are recommended.

Reconstruction of Bottom Surface of Shoe Last Based on Foot Pressure Distribution

The thesis presents a reconstruction of bottom surface of shoe last based on foot pressure distribution in order to relieve the influence caused by plantar pressure concentration. First, in order to match the plantar pressure data and the shoe last data, the shoe last data is processed to locate the center location of the heel, the sole and the big feet thumb. Then the pressure data is also processed to extract the corresponding data which is interpolated and fitted of the area of the heel, the sole and the big feet thumb. and then the establish area of bottom surface is determined depending on the pressure data of three area. Finally, based on the extracted pressure data and the convex-concave coefficient of pressure data, the reconstruction of bottom surface of shoe last is achieved.