Concave Portions Research Articles

A nonparametric least squares regression method for forecasting building energy performance

The Convex Nonparametric Least Squares (CNLS) method assumes that the regression function is either concave or convex to forecast building energy performance. However, there may be instances where the regression function exhibits both concave and convex patterns, rendering this assumption invalid. This paper aims to address this drawback and to derive a new method called Monotone Nonparametric Least Squares (MNLS), which incorporates both concavity and convexity constraints in CNLS. It is proved that MNLS has a better goodness-of-fit performance compared to CNLS. Since MNLS contains both concave and convex portions, it is not sufficient to rely solely on the concavity assumption (or convexity assumption) during the forecasting process of building energy performance. To tackle this issue, using both concave and convex portions separately and then combining the resulting forecasts is suggested. An illustrative example is provided, and the energy performance of Hong Kong secondary schools is used as an application to demonstrate the goodness-of-fit of MNLS.

Miniature Fuel Cell with Monolithically Fabricated Si Electrodes- Application of a PDMS Flow Channel for Operando Observation -

Miniature fuel cells have attracted attention as an ultimate portable power source, and we have developed monolithically fabricated Si electrodes for the miniature fuel cells [1,2]. In the fuel cells, two Si electrodes with porous Pt catalyst layer are pressed onto either side of a PEM (polymer electrolyte membrane) , and the prototype fuel cells showed promising performances of over 500mW/cm2 output at 313K with H2-O2. However, the high output was obtained with only small reaction area. Along with enhancement of the reaction area, the performance dropped. We assumed that the performance drop is caused by flooding due to increased water production, which was ignored because MEMS fuel cells are dimensionally small and the outputs are also small. In this study, we attempted to observe the behavior of produced water on the fuel flow channel using a novel transparent channel cover as shown in figure 1. Furthermore, it was assumed that the produced water stays in the concave portions on the catalyst layer, and stripe-shaped projections were formed on the channel cover to prompt drainage of the produced water from the fuel channels.The transparent fuel channel cover was fabricated with PDMS using soft lithography techniques. Initially, a mold for the cover was made with a dry film resist. Micro stripe pattern with 40μm width were made. Considering the PDMS shrinkage during polymerization, the mold pattern had to be formed a few percent larger than the desired shape. Figure 2 shows the whole view of the PDMS channel cover on a miniature fuel cell with Si electrodes. The reaction on the Si substrate was 1mm and 4mm long. Within the area, 100μm x 100μm sections were etched down to the backside catalyst layer. Magnified view on the reaction area is shown in figure 3. It was found that the stripes were finely aligned on the concave portions on the Si electrode.Figure 4 shows the polarization curves of the power generation tests. Results with the novel fuel channel cover with stripes showed higher output compared to the conventional simple cuboid straight shape cover. Figure 5 shows the microscopic view of the channel. While produce water droplets were observed on downstream area in the conventional cuboid shape channel, no droplets were observed with the novel channel cover. It was assumed that drainage of the produced water was successfully prompted and smooth fuel supply to the catalyst layer was realized by the novel fuel channel cover. Acknowledgement This work was partly performed under the Cooperative Research Program of “NJRC Mater. &Dev.” References [1] M. Kobayashi, T. Suzuki, M. Hayase, Journal of Power Sources, 267, 622-628 (2014).[2] R. Shirai, et al., Journal of The Electrochemical Society, 166(15), D834 (2019) Figure 1

Tectono-geomorphic and active deformation studies in the Ujh basin of Northwestern Himalaya

This study focuses on the morphotectonic analysis of the Ujh River basin, examining various aspects related to geometrical changes in the drainage basin caused by tectonic and erosional processes. The topographic development of the Ujh River basin is a response to enhanced tectonic deformation caused by Main Central Thrust (MCT) and Main Boundary Thrust (MBT). We assume that the basin asymmetry, tilting, incision, and migration of the river basin are regulated by the compressive force generated between MBT and MCT. The results were characterized by a high Asymmetry Factor (Af) indicating greater asymmetry suggesting a rightward tilting with low Valley Floor to Valley Width (Vf) values which indicate differential uplift and incision owing to ongoing tectonic processes. The high Stream Length Gradient (SL) Index values in the MCT zone, indicate sudden topographic breaks caused by the vertical tectonic uplift with active erosion processes. The Ujh River basin is in a disequilibrium state, with convex portions indicating uplift and concave portions indicating subsidence on the slope-area plot. The χ analysis, plotting χ values against elevation, highlights upliftment and erosion zones along the trunk stream, with major slope breaks and high χ values observed in the upstream region, particularly along the MCT. Overall, the Ujh River basin exhibits morphotectonic characteristics indicating ongoing tectonic activity and a state of disequilibrium.

Formation of aligned needle‐like crystals of 9,10‐dibromoanthracene in small droplets

AbstractOne‐dimensional micromaterials are potentially applicable in various technologies, including sensor fabrications. Variations in the sensing performance of such materials can be ameliorated by their regular arrangement. For example, the materials can be aligned unidirectionally. However, controlling both their orientation and spacing remains challenging. In this study, small evenly spaced droplets were aligned on a surface and the solvent in the droplets was then evaporated in air to obtain evenly spaced, aligned needle‐like crystals of the solute. The droplets were confined to the concave portions of regular wrinkles formed due to buckling instability on a polydimethylsiloxane (PDMS) rubber surface. However, crystallization in small droplets with diameters of less than 100 μm was difficult to achieve because the probability of nucleus formation in each droplet was very low. To address this drawback, nuclei were added to the droplets externally, obtaining well‐aligned needle‐like crystals of 9,10‐dibromoanthracene (DBA), an organic semiconductor. The advantages of this method include its simplicity, cost efficiency, and applicability to fragile materials, because the application of mechanical force to the needle‐like crystals is not required.

Defining bounding surfaces within and between eolian and non-eolian deposits, Lower Jurassic Navajo Sandstone, Moab Area, Utah, U.S.A.: Implications for subdividing erg system strata

ABSTRACTA model-independent, sequence stratigraphic approach is used to define bounding surfaces in the Navajo Sandstone in order to identify an architectural hierarchy of genetically related sedimentary packages and the surfaces that bound them across multiple scales of both eolian and non-eolian components of an erg system. Seven bounding surfaces and eight depositional units are defined, from small to large scale. A lamina-deviation surface bounds wedge- and tabular-shaped sets of laminae and/or laminasets, separating those that have different angle orientations on the dune slipface. A bed-deviation surface bounds a succession of beds (crossbeds) that lie at different angles or orientations to bedding above, below, or adjacent to it. A bedset-deviation surface is curved, inclined, and/or wavy and irregular that bounds bedsets and their internal stratification patterns; that is, bed-deviation surfaces, and lamina-deviation surfaces. A simple surface is gently inclined with or without small, concave or convex segments that bound beds and bedsets. A composite surface is horizontal with or without concave, curved, or irregular portions of that surface. A complex surface is laterally extensive (∼ 1–10+ km) that regionally bounds and truncates underlying conterminous and interfingered eolian and non-eolian strata. An amalgamated surface is a regionally extensive (∼ 10 to 100s km) mappable unconformity, merged unconformities, and their laterally equivalent conformable surface that can exhibit local to regional pedogenic modification, lags, and significant (meters to 10s m) paleotopographic relief. The genetically related sedimentary packages typically bounded by like or higher-rank surfaces are defined as laminae, laminasets, bed, bedsets, and simple, composite, complex, and amalgamated units. Field relationships of strata and surfaces are key to reconstructing the interactions between eolian and non-eolian deposits and the processes they represent at the local, regional, and basin scale. This classification scheme can be applied to erg-system strata to fully integrate changes in diverse facies within and between contiguous deposits.

Immobilization of CO2 at Room Temperature Using the Specific Sub‐NM Space of 1D Uneven‐Structured C60 Polymer Film

AbstractImmobilization and reuse of CO2 are urgent tasks for sustaining the global environment. Here it is demonstrated that CO2 can be immobilized by reaction with H2O at room temperature (RT) in the specific sub‐nm space of 1D uneven‐structured C60 polymer (1D polymer) film, even though the reaction does not occur at RT in the gas phase (activation energy: 2 eV). First‐principles calculations reveal that the CO2 molecule is stacked as a bridge between the concave portions of adjacent 1D polymer frameworks via locally induced Coulomb interactions. Such induced charge polarization activates CO2 both by weakening its double‐bonds and by lowering its lowest unoccupied molecular orbital energy due to the bending motion. In addition, the flexible π orbitals of the 1D polymer provide the optimal Coulomb field to stabilize the transition state of the CO2 + H2O reaction remarkably. These factors work together to make the reaction possible at RT.

Polarization of concave domains by traveling wave pinning.

Pattern formation is one of the most fundamental yet puzzling phenomena in physics and biology. We propose that traveling front pinning into concave portions of the boundary of 3-dimensional domains can serve as a generic gradient-maintaining mechanism. Such a mechanism of domain polarization arises even for scalar bistable reaction-diffusion equations, and, depending on geometry, a number of stationary fronts may be formed leading to complex spatial patterns. The main advantage of the pinning mechanism, with respect to the Turing bifurcation, is that it allows for maintaining gradients in the specific regions of the domain. By linking the instant domain shape with the spatial pattern, the mechanism can be responsible for cellular polarization and differentiation.

An Integrated Procedure to Assess the Stability of Coastal Rocky Cliffs: From UAV Close-Range Photogrammetry to Geomechanical Finite Element Modeling

The present paper explores the combination of unmanned aerial vehicle (UAV) photogrammetry and three-dimensional geomechanical modeling in the investigation of instability processes of long sectors of coastal rocky cliffs. The need of a reliable and detailed reconstruction of the geometry of the cliff surfaces, beside the geomechanical characterization of the rock materials, could represent a very challenging requirement for sub-vertical coastal cliffs overlooking the sea. Very often, no information could be acquired by alternative surveying methodologies, due to the absence of vantage points, and the fieldwork could pose a risk for personnel. The case study is represented by a 600 m long sea cliff located at Sant’Andrea (Melendugno, Apulia, Italy). The cliff is characterized by a very complex geometrical setting, with a suggestive alternation of 10 to 20 m high vertical walls, with frequent caves, arches and rock-stacks. Initially, the rocky cliff surface was reconstructed at very fine spatial resolution from the combination of nadir and oblique images acquired by unmanned aerial vehicles. Successively, a limited area has been selected for further investigation. In particular, data refinement/decimation procedure has been assessed to find a convenient three-dimensional model to be used in the finite element geomechanical modeling without loss of information on the surface complexity. Finally, to test integrated procedure, the potential modes of failure of such sector of the investigated cliff were achieved. Results indicate that the most likely failure mechanism along the sea cliff examined is represented by the possible propagation of shear fractures or tensile failures along concave cliff portions or over-hanging due to previous collapses or erosion of the underlying rock volumes. The proposed approach to the investigation of coastal cliff stability has proven to be a possible and flexible tool in the rapid and highly-automated investigation of hazards to slope failure in coastal areas.

Cut Surface Features in Various Die-Cutting Processes

Currently, the shaped parts combined with straight, concave, and convex portions are increasingly fabricated. To produce the straight portion, the shearing theory is usually applied. As well as, to produce the concave and convex portions, the punching and blanking theories are usually applied. However, with the same die-cutting process parameters, the comparison of cut surface features of straight, concave, and convex portions has not been investigated yet. Therefore, in the present research, the comparison of the cut surface features in various die-cutting processes, including shearing, blanking, and punching processes are investigated. The finite element method (FEM) was used as a tool to investigate these cut surface features. The cut surface features were investigated and clearly identified via the changes of the stress distribution analyses. The results elucidated that with the same die-cutting process parameters, the different cut surface features were obtained. Specifically, the crack formations were easily generated in the case of blanking process, following by the shearing and punching processes, respectively. Therefore, the smooth cut surface was smallest in the case of blanking process, following by the shearing and punching processes, respectively. The laboratory experiments were carried out to verify the accuracy of the FEM simulation results. Based on the cut surface features, the FEM simulation results showed good agreement with the experimental results in terms of the cut surface features. Therefore, to design the die-cutting process parameters to meet the product requirements of complicated shapes, the understanding on these working process parameters being upon the shaped parts is necessarily.

表面微細テクスチャによる切削工具・切りくず間の付着拘束緩和が加工力低減に及ぼす影響

Cutting force can be reduced by using surface micro-textured tools even under dry conditions. In the previous research, it was found that the surface textures for reduction in cutting force must have concave portions intermittently at the contact region far away from the cutting edge. This result supposes that textures bring about a reduction in adhesive force acting at the interface and reduce cutting force. In order to investigate an effect of surface textures on reduction in adhesive force, dry friction tests with the loading and unloading process were carried out. The results indicated that the surface textures can reduce the adhesive force. Moreover, a cutting model established by the slip-line field method was proposed in order to consider the effect of adhesive force on the deformation field state including shear angle, chip curl radius and tool-chip contact length which strongly affects cutting force. The change in the deformation field state following the reduction in the adhesive force corresponds to the experimental results with the textured tools. From the results, it was suggested that the mechanisms of reduction in cutting force attached under dry conditions can be well described by considering the existence of adhesive restriction between tool and chip.

Reconstruction of water-tight surfaces through Delaunay sculpting

Given a finite set of points S⊆R2, we define a proximity graph called as shape-hull graph (SHG(S)) that contains all Gabriel edges and a few non-Gabriel edges of Delaunay triangulation of S. For any S, SHG(S) is topologically regular with its boundary (referred to as shape-hull (SH)) homeomorphic to a simple closed curve. We introduce the concept of divergent concavity for simple, closed, planar curves based on the alignment of curves in concave portions and discuss various measures to characterize curves having divergent concavity. Under sufficiently dense sampling, we prove that SH(S), where S is sampled from a divergent concave curve ΣD, represents a piece-wise linear approximation of ΣD. We extend this result to provide a sculpting algorithm for closed surface reconstruction from a set of raw samples. The surface is constructed through a repeated elimination of Delaunay tetrahedra subjected to circumcenter and topological constraints. Theoretically, we justify our algorithm by establishing a topological guarantee on the 3D shape-hull with the help of topological rules. We demonstrate the effectiveness of our approach with experimental results on models with sharp features and sparsely distributed point clouds. Compared to existing sculpting approaches for surface reconstruction that require either a parameter tuning or several stages, our approach is simple, non-parametric, single stage and reconstructs topologically correct piece-wise linear approximation for divergent concave surfaces.

Heuristic Method for Identifying Concave Pareto Frontiers in Multi-Objective Dynamic Programming Problems

Aerospace engineers and analysts tasked with informing system-level decisions commonly seek to identify the frontier of Pareto-optimal solutions with respect to objectives of interest. For problems in which decisions are made over multiple stages or periods, dynamic programming can be an efficient and effective method for identifying such a Pareto frontier. To employ traditional dynamic programming, however, a single objective function must be defined. Aggregation of multiple objectives into a single objective using traditional simple additive weighting has the limitation of permitting identification of only points on convex portions of the Pareto frontier. This can translate into detection of a frontier with significant and misleading gaps. This paper proposes a theory-motivated aggregation function modification and method to improve the ability of dynamic programming procedures to detect concave portions of Pareto frontiers in multi-objective, multistage problems. Following a theoretical motivation and method definition, a military aircraft route planning example is provided to illustrate the method’s accuracy and efficiency.

Laser detection of ultrasonic waves with concave portions of the wave fronts

Special features of ultrasonic pulse wave field detection with concave regions of the wave fronts are investigated with the use of ultrasonic laser interferometry technique. Experimental proofs of the wave front with concave regions are obtained and it is found that the nonmonotonic wave front profiles are well described by the fourth-order even polynomial. The model proposed is applied to the investigation of the spatiotemporal structure of elastic wave fields on solid surfaces. The results obtained can be used for estimating the local wave front curvature.

A Study of the Optical Properties of Cosmetics Measured by Polarized Light Goniophotometry

Polymethylmethacrylate powders are commonly used to improve the spreadability and blurring effects of powder foundation cosmetics. In this study, the opacity and haze effect of four types of polymethylmethacrylate powders and their 10wt% powder foundation formulation was evaluated. The distorted random hemispherical particulates with both concave and convex portions showed the highest haze and opacity value as a single powder substance. And as a formulated phase, the powder foundation formulation containing particulates with fine pores provided the highest haze and opacity value. We also examined the quantity of reflected light over the angular range 20-75° by polarized light goniophotometry. The total reflected light intensity, surface-reflected light, and internally reflected light were characterized. These studies demonstrated that hemispherical PMMA powders produce natural brilliance by creating high internally reflected light which is similar to the total reflection profile of artificial skin.

Edge Extraction using Image and Three-Axis Tactile Data

Abstract This paper describes a hand-arm system equipped with optical three-axis tactile sensors and a binocular vision sensor. The vision compensates for the limitations of tactile information and tactile sensing, and vice versa. The tactile sensor can obtain geometrical data as real scale, while image data requires calibration to obtain length as a metric unit. Even if stereovision is used, we cannot obtain sufficient precision. In the evaluation test, the robotic hand equipped with tactile sensors traces an object including convex and concave portions to evaluate edge trace precision. Error of distance obtained by the binocular vision is around ± 10 mm when distance between the camera and object is around 600 mm. When the hand-arm robot touches the convex portion of the object, size data obtained by the vision is modified within ± 0.5 mm accuracy. Since the robotic finger is too thick to touch the bottom of the concave, size data of the concave portion obtained by tactile sensing includes relatively large error of around 4 mm. However, the robot finger can follow the contour with ± 0.5 mm accuracy except for the bottom portion. Therefore, vision sensing is not sufficient for precise edge exploration and modification based on tactile sensing is required.

Size, species, and fire behavior predict tree and liana mortality from experimental burns in the Brazilian Amazon

Anthropogenic understory fires have affected large areas of tropical forest in recent decades, particularly during severe droughts. Yet, the mechanisms that control fire-induced mortality of tropical trees and lianas remain ambiguous due to the challenges associated with documenting mortality given variation in fire behavior and forest heterogeneity. In a seasonally dry Amazon forest, we conducted a burn experiment to quantify how increasing understory fires alter patterns of stem mortality. From 2004 to 2007, tree and liana mortality was measured in adjacent 50-ha plots that were intact (B0 – control), burned once (B1), and burned annually for 3 years (B3). After 3 years, cumulative tree and liana mortality (≥1 cm dbh) in the B1 (5.8% yr −1) and B3 (7.0% yr −1) plots significantly exceeded mortality in the control (3.2% yr −1). However, these fire-induced mortality rates are substantially lower than those reported from more humid Amazonian forests. Small stems were highly vulnerable to fire-induced death, contrasting with drought-induced mortality (measured in other studies) that increases with tree size. For example, one low-intensity burn killed >50% of stems <10 cm within a year. Independent of stem size, species-specific mortality rates varied substantially from 0% to 17% yr −1 in the control, 0% to 26% yr −1 in B1, and 1% to 23% yr −1 in B3, with several species displaying high variation in their vulnerability to fire-induced mortality. Protium guianense (Burseraceae) exhibited the highest fire-induced mortality rates in B1 and B3, which were 10- and 9-fold greater than the baseline rate. In contrast, Aspidosperma excelsum (Apocynaceae), appeared relatively unaffected by fire (0.3% to 1.0% mortality yr −1 across plots), which may be explained by fenestration that protects the inner concave trunk portions from fire. For stems ≥10 cm, both char height (approximating fire intensity) and number of successive burns were significant predictors of fire-induced mortality, whereas only the number of consecutive annual burns was a strong predictor for stems <10 cm. Three years after the initial burn, 62 ± 26 Mg ha −1 (s.e.) of live biomass, predominantly stems <30 cm, was transferred to the dead biomass pool, compared with 8 ± 3 Mg ha −1 in the control. This biomass loss from fire represents ∼30% of this forest's aboveground live biomass (192 (±3) Mg ha −1; >1 cm DBH). Although forest transition to savanna has been predicted based on future climate scenarios, our results indicate that wildfires from agricultural expansion pose a more immediate threat to the current carbon stocks in Amazonian forests.

Deconvolution of background-subtracted shift-and-add image by a modeled point-spread-function

Shift-and-add (SAA) is a simple method for celestial speckle imaging. However, the raw SAA-image, a direct output of the SAA operations, is not useful, because a seeing-dependent huge background is superimposed on the high-resolution image of the object. To obtain the latter, a background subtraction (BGS) is applied on the raw SAA-image. The BGS-image so obtained includes negativities due to an over-subtraction that causes brightnesses of the object’s image biased downward. The negativity in the BGS-image can be removed by a deconvolution with a point-spread-function (PSF) that has negative values. In this paper, we model the PSF with a shape that possesses peak and concave portions, and perform a deconvolution by iteratively estimating the object’s image and the model parameters. The simulated experiment has shown that the present algorithm can restore the object’s image with unbiased brightnesses. Processing the observed speckle data of Io (a Jupiter satellite) by the present method has yielded a feasible Io image with reduced negativities.

Bubble generation and transport in a microfluidic device with high aspect ratio

Bubble generation and transport in a micro-device composed of a micro-T-junction and a following serpentine micro-channel was experimentally investigated. It has a rectangular cross-sectional with an aspect ratio of 7.425. Air and water were used as gas and liquid, respectively. Mixtures of water–glycerol and water–Tween-20 were used to study the effects of liquid viscosity and surface tension. Compared with previous T-junction bubble generation, the liquid and gas inlets orientation was switched in this work. The continuous flow was driven from the perpendicular channel and the dispersion flow was from the main channel. It shows that the break-up process has three periodic steps under certain operating conditions. The dimensionless bubble length L/ w in the micro-channel with high aspect ratio is much larger than that in square microchannels. A correlation is proposed to correlate L/ w with liquid flow rate J L , gas flow rate J G , and liquid viscosity μ L . Surface tension σ can change the bubble shape but almost does not affect the bubble length in this fast break-up process. Additionally, a long bubble may be broken up at the corners at the same time because the locations of gas and liquid are exchanged relative to the concave and convex portions of an elbow after a turn which may result in the change of fluid velocities and gas–liquid pressure drop.

Surface Acoustic Wave Duplexer Composed of SiO2/Cu Electrode/LiNbO3 Structure Having Convex and Concave Portions

The transition bandwidth of 20 MHz between the transmission (Tx: 1850–1910 MHz) and the receiving (Rx: 1930–1990 MHz) bands of personal communication service (PCS) handy phones in the United States (US) is very narrow compared with those of other systems. We have already realized surface acoustic wave (SAW) duplexers with sizes of 5.0×5.0×1.7 and 3.0×2.5×1.2 mm3 for PCS handy phones in the US with an excellent temperature coefficient of frequency (TCF) by using a shear horizontal (SH) wave on a flattened SiO2/Cu electrode/36–48° YX-LiTaO3 structure and a Rayleigh wave on a SiO2/Cu electrode/120–128° YX-LiNbO3 structure. Although the surface of the above-mentioned structures is flattened SiO2, we have also studied the shape of the SiO2 surface. As a result, in addition to increasing the stop-band width, which corresponds to the reflection coefficient, the TCF and power durability have been improved by forming convex portions on the surface of the SiO2 over the interdigital transducer (IDT) gaps.

The kinematic design of a planar-cam type pick-and-place device

The planar-cam type pick-and-place device can clearly and effectively achieve the desired curvilinear motion of its end effector, and it can be designed and fabricated easily. By employing the concept of velocity instant center, the cam profiles, the paths of cutters, the pressure angles and the radii of curvature of the dual cams of the planar-cam type pick-and-place device can be expressed parametrically. The cam profiles may have concave portions, and each minimum radius of curvature of the concave portion of the dual cam profiles is the upper bound of the grinding-wheel radius that may not cause undercutting.