Horizontal Orientation Research Articles

Dimensioning Cuboid and Cylindrical Objects Using Only Noisy and Partially Observed Time-of-Flight Data.

One of the challenges of using Time-of-Flight (ToF) sensors for dimensioning objects is that the depth information suffers from issues such as low resolution, self-occlusions, noise, and multipath interference, which distort the shape and size of objects. In this work, we successfully apply a superquadric fitting framework for dimensioning cuboid and cylindrical objects from point cloud data generated using a ToF sensor. Our work demonstrates that an average error of less than 1 cm is possible for a box with the largest dimension of about 30 cm and a cylinder with the largest dimension of about 20 cm that are each placed 1.5 m from a ToF sensor. We also quantify the performance of dimensioning objects using various object orientations, ground plane surfaces, and model fitting methods. For cuboid objects, our results show that the proposed superquadric fitting framework is able to achieve absolute dimensioning errors between 4% and 9% using the bounding technique and between 8% and 15% using the mirroring technique across all tested surfaces. For cylindrical objects, our results show that the proposed superquadric fitting framework is able to achieve absolute dimensioning errors between 2.97% and 6.61% when the object is in a horizontal orientation and between 8.01% and 13.13% when the object is in a vertical orientation using the bounding technique across all tested surfaces.

Acoustic Target Strength of Jellyfish, Nemopilema nomurai, Measured at Multi-Frequency and Multi-Orientation

The jellyfish Nemopilema nomurai occupies an important position in the Northwest Pacific ecosystem, and monitoring its biomass is necessary to ensure the protection of fishery resources and the safety of offshore industrial production. The acoustic method has been proposed for jellyfish flux estimation and bloom warning, in which the target strength (TS) of the jellyfish is a crucial parameter. However, varied swimming orientations of jellyfish aggregation result in different backscatter strengths. The acoustic echo characteristics in horizontal swimming orientations and multi-frequency broadband signals are yet to be revealed. This study aims to obtain the TS of jellyfish in various orientations and to comprehensively investigate the jellyfish acoustic echo features at various frequency broadband sounds. In an anechoic tank, we used wide-band echosounder and 70 kHz, 120 kHz, and 200 kHz split-beam transducers to measure the TS of jellyfish swimming omnidirectionally. The results show a difference of approximately 4 dB in the jellyfish’s normalized TS at 70 kHz (frequency range: 45 kHz to 95 kHz) and 200 kHz (frequency range: 160 kHz to 260 kHz) center frequency. The normalized TS of jellyfish varies by around 8 dB between horizontal and vertical swimming orientations. For jellyfish swimming horizontally, the TS and bell diameter have the following least squares fits: T S D 70 k H z = 20 log D − 89.36 r 2 = 0.83 ; T S D 200 k H z = 20 log D − 93.85 r 2 = 0.83 . The swimming orientation has significant effects on TS estimation and model construction.

Wicking assisted condenser platform with patterned wettability for space application

Vapor condensation is extensively used in applications that demand the exchange of a substantial amount of heat energy or the vapor-liquid phase conversion. In conventional condensers, the condensate removal from a subcooled surface is caused by gravity force. This restricts the use of such condensers in space applications or horizontal orientations. The current study demonstrates proof-of-concept of a novel plate-type condenser platform for passively removing condensate from a horizontally oriented surface to the surrounding wicking reservoir without gravity. The condensing surface is engineered with patterned wettabilities, which enables the continuous migration of condensate from the inner region of the condenser surface to the side edges via surface energy gradient. The surrounding wicking reservoir facilitates the continuous absorption of condensate from the side edges. The condensation dynamics on different substrates with patterned wettabilities are investigated, and their condensation heat transfer performance is compared. The continuous migration of condensate drops from a superhydrophobic to a superhydrophilic area can rejuvenate the nucleation sites in the superhydrophobic area, resulting in increased heat transport. The proposed condenser design with engineered wettability can be used for temperature and humidity management applications in space.

Impact of Notches on Additively Manufactured Inconel 718 Tensile Performance.

This study was completed in effort to characterize the notch sensitivity of additively manufactured (AM) Inconel 718 produced by laser powder bed fusion (L-PBF). Three different root radii on V-notched test specimens and smooth specimens were evaluated under tensile conditions for specimens built in vertical and horizontal orientations. Both the total axial strain and localized notch diametral strain were measured. Finite element analysis (FEA) was completed on each specimen geometry to confirm the actual strain measurements near the notch. Test results showed the tensile strength of the notched specimens were larger than the tensile strength values of the smooth specimens. These tensile results equate to a notch-sensitivity ratio (NSR) greater than one, indicating that the L-PBF Inconel 718 material is a notch-strengthened material. It is suspected that the notch strengthening is a result of increased triaxial stress produced near the notch tip causing added material constraints, resulting in higher strength values for the notched specimens. Fractography analysis was completed on the various fracture surfaces and identified a dominate ductile failure mode within all of the specimens; however, the amount of ductility reduced with smaller notch root radii. While this study provides the initial notch responses of the L-PBF Inconel 718, further research must be completed in regard to the impact of notches on more complex loading behaviors, such as fatigue and stress-rupture conditions.

Enhanced performance of solution processed OLED devices based on PFO induced TADF emission layers

The internal quantum efficiency (IQE) of the OLED devices based on thermally activated delayed fluorescence (TADF) materials was thought to nearly 100 % by assuming the light outcoupling efficiency of 20–25 %. However, the external quantum efficiency (EQE) is still limited by the ηout. One crucial factor that affects the light output coupling efficiency is the molecular transition dipole moment of the emission molecule. In this study, poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) was chosen as an orientation inducer to enhance the horizontal orientation ratio of a TADF emitter, 2-Phenyl-4,6-bis[4-(9,9-dimethyl-9,10-dihydroacridine) phenyl] pyrimidine (DMAc-PPM), prepared using a solution method. With doping PFO in weight ratios ranging from 1 wt% to 9 wt%, the orientation factor of TADF emitter increased, which testified the inducing function of PFO. The TADF-OLED devices using PFO as an inducer exhibited an EQE increasing with the PFO doping weight ratio. The maximum EQE of 7.3 % was achieved at the doping weight ratio of 7 wt%, which increase about 1.7 times compared to the device without the PFO inducer. This observed variation of EQE differs from the trend observed in maximum luminance intensity. The increase of EQE can be attributed to the improvement of light output efficiency caused by the variation of orientation factor. The lower carrier mobility lead to the lower maximum luminance intensity. The synergistic effect of light output efficiency and carrier mobility enhanced the performance of OLED devices.

Numerical simulation and analysis of heat transfer and melting rate of nano-enhanced PCM composite embedded in a concentrator photovoltaic system

The primary objective of this research is to explore the impact of nanoparticles-infused PCM (phase change material) in the context of nano-PCM-PV technology (PV: photovoltaic panel). Computational investigations were conducted to evaluate the effectiveness of RT25HC, a paraffin wax PCM, in conjunction with various nanoparticles (MgO, TiO2, ZnO and CuO) in solar panel cooling. The study also considers the influence of PV module inclination angles (β: 0 to 90°). High-resolution numerical simulations using the ANSYS-Fluent CFD platform were employed. The findings highlight the intricate relationship between nanoparticle addition, melting kinetics, electrical efficiency and PCM enthalpy. Specifically, the melting rate of RT25HC PCM exhibits notable differences between horizontal (β = 0°) and inclined panels (β ≠ 0°), with a melting fraction of 12 % at t = 2 h for β = 0° compared to 40–44 % for β ≠ 0°. Nanoparticles maintain a higher electrical efficiency (11.6 %) for horizontal panels, whereas inclined panels (β ≠ 0°) experience declining electrical efficiency (7.5 % at t = 8 h). For β = 0°, the PCM system effectively maintains the surface panel's temperature constant at 44 °C for a long time (up to 8 h). However, when nano-PCM systems are introduced, this temperature stabilizes at a slightly lower value of 40 °C, representing a 4 °C reduction attributed to the presence of nanoparticles. Conversely, for β ≠ 0, the surface panel's temperature stabilizes at 44 °C for up to t = 2 h, then experiences a sharp increase, ultimately reaching 120 °C at t = 8 h, regardless of the type or absence of nanomaterials. Overall, the most effective application of nano-PCM for cooling the PV panel was predicted at a horizontal orientation of the panel, regardless of the nanomaterial type.

Onset and performance of a two layer oscillating heat pipe in a heat spreader

Experiments were performed to characterize a two-layer oscillating heat pipe in a heat spreading plate heated locally on one side and cooled throughout the other side. The 23-turn oscillating heat pipe with 2 mm hydraulic diameter square channels and interconnected between the layers was charged with a 70 percent fluid loading of degassed DI water. The effect of heating location, operating temperature and orientation were examined. The results showed that the thermal conductance (W/K) of the plate could be increased by more than 100 percent for a heater position near the edge of the plate but less for a central position where conduction through the plate was more effective. The change in the thermal conductance of the oscillating heat pipe path with the effective heat transfer through this path appeared independent of heater position but decreased modestly with operating temperature and for a horizontal plate orientation. The operation of the oscillating heat pipe was correlated using the heated wall superheat and the change in saturation pressure with temperature. The results suggest these were inversely correlated but the boundary delineating the onset of operation depended on orientation. Evidence of hysteresis effects and suppression of oscillation were observed.

Microstructural evolution and mechanical properties of Ti-6Al-4V in situ alloyed with 3.5 wt.% Cu by laser powder bed fusion

The present work deals with the fabrication of Ti-6Al-4V in situ alloyed with 3.5 wt.% Cu (Ti-6Al-4V–3.5Cu), its microstructural evolution, and its related tensile properties. Specimens with a relative density of 99 ± 0.1% presented a microstructure that differed from that of pure Ti-6Al-4V in LPBF, which usually exhibits a fully martensitic structure (α′). In Ti-6Al-4V–3.5Cu, apart from α-Ti, β-Ti, and intermetallic Ti2Cu were also observed, generated by in situ martensite decomposition. Initially solidified large columnar β-Ti grains underwent a martensitic transformation to α′. Cyclic reheating caused by layer-wise deposition during LPBF enabled the diffusion of Cu and V, allowing the transformation of α′ to stable α-Ti and the precipitation of β-Ti and Ti2Cu. The α′ decomposition and formation of β-Ti and Ti2Cu contributed to an UTS of 1362 ± 14 MPa and an Rp0.2 of 1313 ± 14 MPa in the horizontal specimen orientation in the as-built state. The elongation at fracture was 3.9 ± 0.6%. In the vertical orientation, the specimens exhibited an UTS of 1305 ± 19 MPa, an Rp0.2 of 1215 ± 23 MPa, and an elongation at fracture of 5.4 ± 1.5%. Stress-relief annealing reduced the UTS and Rp0.2 to 1099 ± 6 MPa and 1014 ± 5 MPa, respectively, with an increase in elongation at fracture to 6.7 ± 0.4% in the horizontal specimen orientation. In the vertical specimen orientation, stress relief annealing resulted in an UTS of 1051 ± 13 MPa and an Rp0.2 of 926 ± 18 MPa. The elongation at fracture was increased to 11.3 ± 1.3%.

Head-to-Head Analysis of Vertical vs Horizontal Incision Patterns in Breast Reconstruction: Surgical Outcomes and Aesthetic Implications.

Modern aesthetically optimized breast reconstruction requires collaboration between the patient, breast surgeon, and plastic surgeon. To optimize both surgical outcome and aesthetic results, incision patterns must be carefully planned. We aimed to determine whether vertical or horizontal orientation of mastectomy incision was preferred in the general population and to analyze corresponding complication profiles. A retrospective review was performed of all patients undergoing bilateral mastectomy followed by autologous breast reconstruction utilizing either vertical or horizontal incision from January 2011 to November 2022. Postoperative complications of the 2 incision patterns were analyzed. Additionally, crowdsourcing was utilized to assess aesthetic implications of horizontal and vertical incision patterns on postoperative pictures of completed breast reconstruction. Survey rater demographics were also analyzed to assess differences in scoring based on voter characteristics. There were no significant differences in postoperative breast complications between patients with horizontal or vertical incisions when considering wound, infection, seroma, hematoma, fat necrosis, or overall complications (P > .05). Crowdsourcing showed that, regardless of voter demographics, vertical incisions were preferred over horizontal incisions (P < .001). Additionally, voters who knew someone who had undergone breast reconstruction were more likely to rate all incision patterns higher than other voters (P < .001). Although there are no significant differences in complication profiles between vertical and horizontal incisions in autologous breast reconstruction patients, vertical incision patterns are preferred aesthetically by the general population.

Study on Mechanical Properties of Pineapple Leaf-Glass Fiber Hybrid Composites for Car Body Applications

The purpose of this study was to determine the mechanical properties of glass fiber composites and fiber, orientation and variations pineapple with a different composition of the main tarik.Bahan tests used are glass fiber, pineapple fiber, lye (NaOH), epoxy resin and hardener. Specimens composites made by the method of hand lay up with variations in the composition of the glass fiber 6%: pineapple fiber 4%, the glass fiber 9%: pineapple fiber 6%, glass fibers 12%: pineapple fiber 8%, glass fibers 15%: pineapple fiber 10% and with random fiber orientation and horizontal. Making the specimens was performed by reference to standard ASTM D 638.Hasil this test shows that the highest tensile strength in horizontal fiber orientation with the volume fraction of 25% sebesar143.98 MPa, while the lowest occurred in a random fiber orientation of 10% amounting to 13.45 MPa. Fault Composite glass fiber and epoxy pineapple fiber bermatrik average can be classified as a single fracture type.

First-principles calculation of cresol contaminants removal from wastewater environment

In this study, the environment of different cresol (O-cresol, M-cresol, P-cresol) molecules in wastewater were simulated, so as to construct calculation models for the adsorption of single and multiple cresol molecules on Ag(111) surface. All the first-principles calculations are based on the density functional theory. The analysis of adsorption parameters shows that the aromatic ring plane remained horizontal orientation, but the methyl group and the hydroxyl group tilt upward. With the increasing number of cresol molecules, angles between the aromatic ring plane and the top atomic plane of Ag(111) surface increase, and this phenomenon is more obvious in 1O-1M_Ag(111) system. The angle between the aromatic ring plane of cresol molecule and the top atomic plane of Ag(111) surface does not change significantly when three types of cresol molecules are adsorbed, indicating that there is no strong effect between adsorbed cresol molecule and Ag(111) surface. The shortest atomic distance of 3O_Ag(111) system is 1.418 Å and its corresponding maximum adsorption energy is 13.190 eV. It indicates that the structure is the most stable and the adsorption process is the easiest to occur. Results of electron structure analysis show that the superposition peaks (-1.6eV) of O-p orbital and C-p orbital are closer to the Fermi level during the adsorption of single P-cresol molecule, indicating that the system is unstable. For two cresol molecules, 1O-1P_Ag(111) adsorption system shows more superimposed peaks in the range of (-15∼-2) eV. The number of overlapping peaks of adsorption of three types of cresols decreases due to the addition of the third type of cresol molecule. More charge transfers between Ag(111) surface and cresol molecules are observed in 3O_Ag(111) and 1O-1M_Ag(111) adsorption systems, which confirm the strong adsorption effect between them.

Origins of the improved device performance in solution-processed TADF organic light-emitting devices with a polymer underneath layer

In solution-processed organic light-emitting devices (OLEDs), a polymer interface layer underneath the emission layer is essential to improving the device's performance. The typical polymer is Poly (9-vinylcarbazole) (PVK), which can dramatically increase the device efficiency whereas the mechanisms are not well understood. In this work, we explored the related mechanisms by smart experimental design and measurements. The results reveal that in addition to reducing the hole current density and balancing the carrier distribution, the PVK underneath layer also improves the film morphology and enhances the horizontal orientation of the transition dipole moment of the thermally activated delayed fluorescence (TADF) emitters. Consequently, the device's efficiency and stability are notably increased by about three times. This work provides insights into the origins of improved device performance in solution-processed TADF OLEDs with a polymer underneath layer and also highlights the effect of the underneath layer on the film formation of the solution-processed emission layer.

Stress Constraints From Shear‐Wave Analysis in Shallow Sediments at an Actively Seeping Pockmark on the W‐Svalbard Margin

AbstractMechanisms related to sub‐seabed fluid flow processes are complex and inadequately understood. Petrophysical properties, availability of gases, topography, stress directions, and various geological parameters determine the location and intensity of leakage which change over time. From tens of seafloor pockmarks mapped along Vestnesa Ridge on the west‐Svalbard margin, only six show persistent present‐day seepage activity in sonar data. To investigate the causes of such restricted gas seepage, we conducted a study of anisotropy within the conduit feeding one of these active pockmarks (i.e., Lunde Pockmark). Lunde is ∼400–500 m in diameter, and atop a ∼300–400 m wide seismic chimney structure. We study seismic anisotropy using converted S‐wave data from 22 ocean‐bottom seismometers (OBSs) located in and around the pockmark. We investigate differences in symmetry plane directions in anisotropic media using null energy symmetries in transverse components. Subsurface stress distribution affects fault/fracture orientations and seismic anisotropy, and we use S‐wave and high‐resolution 3D seismic data to infer stress regimes in and around the active seep site and study the effect of stresses on seepage. We observe the occurrence of changes in dominant fault/fracture and horizontal stress orientations in and around Lunde Pockmark and conclude minimum (NE‐SW) and maximum (SE‐NW) horizontal stress directions. Our analysis indicates a potential correlation between hydrofractures and horizontal stresses, with up to a ∼32% higher probability of alignment of hydrofractures and faults perpendicular to the inferred minimum horizontal stress direction beneath the Lunde Pockmark area.

Monitoring of Pore Orientation by in Operando Grazing Incidence Small-Angle X-ray Scattering during Templated Electrodeposition of Mesoporous Pt Films.

We have used in operando grazing incidence small-angle X-ray scattering (GISAXS) to monitor structural changes during templated electrodeposition of mesoporous platinum films on gold electrodes from a ternary lyotropic liquid crystalline mixture of aqueous hexachloroplatinic acid and the diblock copolymer surfactant Brij56. While the cylindrical micelles of the lyotropic liquid crystal (LLC) in the hexagonal phase have a center-to-center distance of 7.5 nm with a preferential alignment parallel to the electrode surface, the electrodeposited platinum films contain highly ordered mesopores arranged in a 2D hexagonal structure, with a center-to-center distance of about 8.5 nm and a preferential orientation perpendicular to the electrode surface. The progression of structural changes of the LLC template and the deposited mesoporous Pt could be monitored for the first time in operando by GISAXS: within the first 14 s of deposition, a nucleation burst of Pt coincides with a loss of preferential alignment of the LLC. Initially, the morphology of the 2-dimensionally nucleated Pt replicates the Au substrate. During the following 5 to 7 min, the growth morphology of the Pt film changes, and vertically aligned mesopores form. Our results indicate mutual interaction between the species involved in the electrodeposition and the LLC template, leading to a partial loss of horizontal orientation of the LLC during Pt nucleation before vertical rearrangement of the micelles to the electrode surface. The vertically aligned mesopores in the Pt and the possibility to produce freestanding films make these materials interesting in fields such as electrocatalysis, energy harvesting, and nanofluidics.

Evaluation of Empirical Separation Efficiency Theories for Uniflow Cyclones for Different Particle Types and Experimental Verification

Cyclones serve as essential devices in various industries for the removal of particulate matter from gases and liquids, contributing to improved equipment efficiency and longevity by mitigating the wear and damage caused by dust and small particles. Uniflow cyclones offer improved accessibility due to their predominantly horizontal orientation. This characteristic enhances the ease of maintenance and operation. This study focuses on investigating the collection efficiency of uniflow centrifugal cyclones for oil mist and fine dust particles ranging from 0.5µm to 29 µm in diameter. The investigation is based on the specific vane angles βv of a swirl inducer from 0∘ to 60∘ at a flow rate V˙ of 130 Ls−1. The measured collection efficiencies are compared with theoretical efficiencies calculated using six different empirical approaches. The different results for oil and fine dust particles are discussed. Comparison of the experimental results with the empirical models demonstrated that certain models closely matched the observed separation efficiencies for different aerosols and vane angles βv (respectively, their induced radial velocities V). Through a systematic examination, this research aims to provide more insight into the validity of empirical approaches for different particle types and compositions using a uniflow-cyclonic system.

Non‐Doped Blue AIEgen‐Based OLED with EQE Approaching 10.3 %

AbstractAggregation‐induced emission (AIE) luminogens (AIEgens) are attractive for the construction of non‐doped blue organic light‐emitting diodes (OLEDs) owning to their high emission efficiency in the film state. However, the large internal inversion rate (kIC(Tn)) between high‐lying triplet levels (Tn) and Tn‐1 causes a huge loss of triplet excitons, resulting in dissatisfied device performance of these AIEgens‐based non‐doped OLEDs. Herein, we designed and synthesized a blue luminogen of DPDPB‐AC by fusing an AIEgen of TPB‐AC and a DMPPP, which feature hot exciton and triplet‐triplet annihilation (TTA) up‐conversion process, respectively. DPDPB‐AC successfully inherits the AIE feature and excellent horizontal dipole orientation of TPB‐AC. Furthermore, it owes smaller kIC(Tn) than TPB‐AC. When DPDPB‐AC was applied in OLED as non‐doped emitting layer, an outstanding external quantum efficiency of 10.3 % and an exceptional brightness of 69311 cd m−2 were achieved. The transient electroluminescent measurements and steady‐state dynamic analysis confirm that both TTA and hot exciton processes contribute to such excellent device performance. This work provides a new insight into the design of efficient organic fluorophores by managing high‐lying triplet excitons.

Non-Doped Blue AIEgen-Based OLED with EQE Approaching 10.3 .

Aggregation-induced emission (AIE) luminogens (AIEgens) are attractive for the construction of non-doped blue organic light-emitting diodes (OLEDs) owning to their high emission efficiency in the film state. However, the large internal inversion rate (kIC (Tn) ) between high-lying triplet levels (Tn ) and Tn-1 causes a huge loss of triplet excitons, resulting in dissatisfied device performance of these AIEgens-based non-doped OLEDs. Herein, we designed and synthesized a blue luminogen of DPDPB-AC by fusing an AIEgen of TPB-AC and a DMPPP, which feature hot exciton and triplet-triplet annihilation (TTA) up-conversion process, respectively. DPDPB-AC successfully inherits the AIE feature and excellent horizontal dipole orientation of TPB-AC. Furthermore, it owes smaller kIC (Tn) than TPB-AC. When DPDPB-AC was applied in OLED as non-doped emitting layer, an outstanding external quantum efficiency of 10.3 % and an exceptional brightness of 69311 cd m-2 were achieved. The transient electroluminescent measurements and steady-state dynamic analysis confirm that both TTA and hot exciton processes contribute to such excellent device performance. This work provides a new insight into the design of efficient organic fluorophores by managing high-lying triplet excitons.

Ultrahigh-resolution 9C seismic survey in a landslide prone area in southwest of Sweden

SUMMARY We studied the benefits of a nine-component (9C) seismic survey over a landslide-prone area in southwest of Sweden to retrieve ultrahigh-resolution shear wave reflection images of the subsurface as well as crucial information on physical properties of the sediments. A complete, 1 m shot and receiver spacing, multicomponent 2-D seismic profile was acquired using three-component microelectromechanical-system-based landstreamer receivers, and a 5-kg sledgehammer strike in vertical and horizontal orientations as three-component seismic source. Given the rich number of shear wave reflections observed on all the 9C data, the processing work focused on their retrievals. It revealed three distinct reflections, two of which associated with coarse-grained materials and one with an extremely undulating bedrock surface. Given the extremely slow shear wave velocities on the order of 60–100 m s−1, we obtained ultrahigh-resolution shear wave sections avoiding temporal and spatial aliasing. Imaging results suggest vertical-source and horizontal-radial receiver (V–HR), and horizontal-transverse source–receiver orientations (HT–HT) provided the most optimum images of the subsurface. A non-hyperbolic algorithm was applied to the normal-moveout corrections justified by the traveltime differences of the bedrock reflection in different shear wave sections. The improved images by incorporating the anisotropy term suggest that the data set reveals moderate shear wave anisotropy along some portions of the profile. The Vp/Vs ratio obtained by using bedrock reflection in P- and S-wave sections suggests values ranging 10–16, which implies high water content. Areas with lower Vp/Vs coincides with greater anisotropic parameters and this can indicate disturbed clays or presence of sensitive clays.

High-performance blue OLED using multiresonance thermally activated delayed fluorescence host materials containing silicon atoms

We report three highly efficient multiresonance thermally activated delayed fluorescence blue-emitter host materials that include 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene (DOBNA) and tetraphenylsilyl groups. The host materials doped with the conventional N7,N7,N13,N13,5,9,11,15-octaphenyl-5,9,11,15-tetrahydro-5,9,11,15-tetraaza-19b,20b-diboradinaphtho[3,2,1-de:1’,2’,3’-jk]pentacene-7,13-diamine (ν-DABNA) blue emitter exhibit a high photoluminescence quantum yield greater than 0.82, a high horizontal orientation greater than 88%, and a short photoluminescence decay time of 0.96–1.93 μs. Among devices fabricated using six synthesized compounds, the device with (4-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)phenyl)triphenylsilane (TDBA-Si) shows high external quantum efficiency values of 36.2/35.0/31.3% at maximum luminance/500 cd m−2/1,000 cd m−2. This high performance is attributed to fast energy transfer from the host to the dopant. Other factors possibly contributing to the high performance are a T1 excited-state contribution, inhibition of aggregation by the bulky tetraphenylsilyl groups, high horizontal orientation, and high thermal stability. We achieve a high efficiency greater than 30% and a small roll-off value of 4.9% at 1,000 cd m−2 using the TDBA-Si host material.

Using fracture-based continuum modeling of coupled geomechanical-hydrological processes for numerical simulation of hydraulic fracturing

This paper describes numerical simulation of hydraulic fracturing using fracture-based continuum modeling (FBCM) of coupled geomechanical-hydrological processes to evaluate a technique for high-density fracturing and fracture caging. The simulations are innovative because of modeling discrete fractures explicitly in continuum analysis. A key advantage of FBCM is that fracture initiation and propagation are modeled explicitly without changing the domain grid (i.e. no re-meshing). Further, multiple realizations of a preexisting fracture distribution can be analyzed using the same domain grid. The simulated hydraulic fracturing technique consists of pressurizing multiple wells simultaneously: initially without permeating fluids into the rock, to seed fractures uniformly and at high density in the wall rock of the wells; followed by fluid injection to propagate the seeded fracture density hydraulically. FBCM combines the ease of continuum modeling with the potential accuracy of modeling discrete fractures and fracturing explicitly. Fractures are modeled as piecewise planar based on intersections with domain elements; fracture geometry stored as continuum properties is used to calculate parameters needed to model individual fractures; and rock behavior is modeled through tensorial aggregation of the behavior of discrete fractures and unfractured rock. Simulations are presented for previously unfractured rock and for rock with preexisting fractures of horizontal, shallow-dipping, steeply dipping, or vertical orientation. Simulations of a single-well model are used to determine the pattern and spacing for a multiple-well design. The results illustrate high-density fracturing and fracture caging through simultaneous fluid injection in multiple wells: for previously unfractured rock or rock with preexisting shallow-dipping or horizontal fractures, and in situ vertical compressive stress greater than horizontal. If preexisting fractures are steeply dipping or vertical, and considering the same in situ stress condition, well pressurization without fluid permeation appears to be the only practical way to induce new fractures and contain fracturing within the target domain.