Explore the vast range of titles available.

Jet electrochemical machining (Jet-ECM) is a significant prospective electrochemical machining process for the fabrication of micro-sized features. Traditionally and normally, the Jet-ECM process is carried out with its electrolytic jet being vertically impinged downstream against the workpiece. Therefore, other jet orientations, including a vertically upstream orientation and a horizontal orientation, have rarely been adopted. In this study, three jet orientations were applied to electrolytic jet machining, and the effect of jet orientations on machining characteristics was systemically investigated. Horizontal jet orientation is of great benefit in achieving accurate micro-sized features with excellent surface quality with either a static jet or a scanning jet for the Jet-ECM. On the other hand, the Jet-ECM with a horizontal jet orientation has a smaller material removal rate (MMR) than the ones with vertical jet orientations, which have almost the same MMR. It was found that an enhancement of machining localization and a reduction of MMR for horizontal jet electrochemical machining primarily results from an improvement of the mass-transfer field. The horizontal orientation of the jet is beneficial for the Jet-ECM processes to improve machining accuracy.

Organic light-emitting diode (OLED) technology is promising for ultrahigh-definition displays and other applications, but further improvements in efficiency and colour purity are desired. Here, we designed and synthesized an ultrapure green emitter called DBTN-2, which is organoboron based and features a highly distorted fused π-conjugated molecular design. This design concept substantially reduces the relaxation energy between the geometries of the excited and ground states, leading to a full-width at half-maximum emission of only 20 nm. Furthermore, the different excitation characters of the singlet and triplet states enhance the spin–orbit couplings leading to highly efficient operation. The introduction of the multiple carbazole moieties gives rise to a charge-resonance-type excitation feature of the triplet states, thus resulting in a high density of the triplet states and a rate of reverse intersystem crossing (kRISC) as fast as 1.7 × 105 s−1. An ultrapure green OLED exploiting DBTN-2 as an emitter without optimized cavity effects and colour filters operated with Commission Internationale de l’Eclairage coordinates of (0.19, 0.74), satisfying the requirement for a commercial green OLED display. Moreover, in combination with a photoluminescence quantum yield of near 100% and a strong horizontal dipole orientation in the doped film, an excellent external quantum efficiency of 35.2% with suppressed efficiency roll-off is simultaneously obtained.An organoboron-emitter, DBTN-2, yields a green organic light-emitting diode with ultrapure colour and high efficiency.

The detection of cosmic neutrinos with energies above a teraelectronvolt (TeV) offers a unique exploration into astrophysical phenomena 1 , 2 – 3 . Electrically neutral and interacting only by means of the weak interaction, neutrinos are not deflected by magnetic fields and are rarely absorbed by interstellar matter: their direction indicates that their cosmic origin might be from the farthest reaches of the Universe. High-energy neutrinos can be produced when ultra-relativistic cosmic-ray protons or nuclei interact with other matter or photons, and their observation could be a signature of these processes. Here we report an exceptionally high-energy event observed by KM3NeT, the deep-sea neutrino telescope in the Mediterranean Sea 4 , which we associate with a cosmic neutrino detection. We detect a muon with an estimated energy of 12 0 − 60 + 110 petaelectronvolts (PeV). In light of its enormous energy and near-horizontal direction, the muon most probably originated from the interaction of a neutrino of even higher energy in the vicinity of the detector. The cosmic neutrino energy spectrum measured up to now 5 , 6 – 7 falls steeply with energy. However, the energy of this event is much larger than that of any neutrino detected so far. This suggests that the neutrino may have originated in a different cosmic accelerator than the lower-energy neutrinos, or this may be the first detection of a cosmogenic neutrino 8 , resulting from the interactions of ultra-high-energy cosmic rays with background photons in the Universe. A very high-energy muon observed by the KM3NeT experiment in the Mediterranean Sea is evidence for the interaction of an exceptionally high-energy neutrino of cosmic origin.  

Two-phase flow boiling of working fluid within a closed-loop oscillating heat pipe in the horizontal orientation (HCLOHP) was studied visually. The HCLOHP was made of Pyrex glass tubes with an inside and outside diameter of 2 and 7 mm, respectively. The evaporator, adiabatic and condenser of the HCLOHP were 50 mm in length. The internal flow phenomena was carefully investigated for various number of turns, evaporator temperatures and filling ratios of the two working fluids, i.e. distilled water and absolute ethanol. The HCLOHP was installed on cooling and heating copper plates and the two-phase flow patterns were recorded by digital still and video cameras. The rate of heat transferred to the cooling water at the condenser was evaluated. The fluid motion characteristics may be separated into two main conditions viz., the oscillating slug flow and the standstill condition. The thermal performance improved when the number of turns reached the critical value of 10 turns at which the vapor fraction was small and the time fraction of oscillating flow was long. For both working fluids, the time fraction of oscillating flow was longest for 50% filling ratio, which led to the lowest thermal resistances. The wavy vapor-liquid interface which induced the vapor/liquid slug train formation was only found for water. Nucleate boiling followed by oscillating flow was discovered in the evaporator part only at the 50% and 80% filling ratios of water. At these filling ratios the thermal resistance of water tended to be lower than that of ethanol.

In this study, the effect of different horizontal and vertical orientations of a model sample (cuboid gellan gel samples containing Maillard reactants) on microwave heat processing was investigated in the solid-state and magnetron microwave systems. To achieve this target, seven orientations inside both microwave cavities were defined. Two of the investigated sample orientations were in a vertical position with and without turntable rotation, and five in a horizontal position. Furthermore, samples at horizontal orientations were put at an angle position without turntable rotation. To analyze the microwave heating patterns, infrared (IR) pictures and photographs of the gellan gel samples were taken after processing to document IR-based thermal and Maillard color changes, respectively. Three main factors for improvement of the heating homogeneity were identified: first, processing samples in the solid-state microwave system; second, position variation of the sample by turntable activated; and third, horizontal orientation. In addition, it was observed that placing the gellan gel samples in a vertical position in the magnetron microwave system resulted in considerably more absorbed power and a more uniform microwave heat processing compared to other horizontal orientations in this system. This indicated a non-uniform microwave field distribution. The results of this study can also confirm the importance of designing suitable food packaging: a vertical shape for more microwave energy absorbance and thus, more energy efficiency, and a horizontal shape for more uniform microwave heat processing.

After investigation, it was found that due to natural environmental conditions such as rain and snow temperature, equipment such as down conductor above the terminals, and natural swings of wires, the terminal blocks of the down conductor bushing on the high voltage side of the main transformer of a 500kV substation will deteriorate and deform. Following the force analysis and experiment on the down conductor bushing terminal block on the high voltage side of the main transformer, it is found that the weak structure of the bushing terminal block lies in the vertical orientation of the terminal and the connection point of the transverse structure, and its horizontal external force limit value is 1.91KN. In this paper, it was finally decided to improve the terminal structure by erecting diagonal supports between the vertical and transverse structures of the terminals. The improved terminal block can be subjected to an external force of 5KN horizontally, and the terminal shape is within the safe range. It can ensure the safety and stability of the main transformer bushing terminal block.

Bright and efficient organic emitters of near-infrared light would be of use in applications ranging from biological imaging and medical therapy to night-vision devices. Here we report how a new class of Pt( II ) complex phosphors have enabled the fabrication of organic light-emitting diodes that emit light at 740 nm with very high efficiency and radiance due to a high photoluminescence quantum yield of ∼81% and a highly preferred horizontal dipole orientation. The best devices exhibited an external quantum efficiency of 24 ± 1% in a normal planar organic light-emitting diode structure. The incorporation of a light out-coupling hemisphere structure further boosts the external quantum efficiency up to 55 ± 3%. New design of Pt( II ) phosphors yield near-infrared organic light-emitting diodes with high efficiency and brightness.

The cytotoxicity of 2D graphene-based nanomaterials (GBNs) is highly important for engineered applications and environmental health. However, the isotropic orientation of GBNs, most notably graphene oxide (GO), in previous experimental studies obscured the interpretation of cytotoxic contributions of nanosheet edges. Here, we investigate the orientation-dependent interaction of GBNs with bacteria using GO composite films. To produce the films, GO nanosheets are aligned in a magnetic field, immobilized by crosslinking of the surrounding matrix, and exposed on the surface through oxidative etching. Characterization by small-angle X-ray scattering and atomic force microscopy confirms that GO nanosheets align progressively well with increasing magnetic field strength and that the alignment is effectively preserved by crosslinking. When contacted with the model bacterium Escherichia coli, GO nanosheets with vertical orientation exhibit enhanced antibacterial activity compared with random and horizontal orientations. Further characterization is performed to explain the enhanced antibacterial activity of the film with vertically aligned GO. Using phospholipid vesicles as a model system, we observe that GO nanosheets induce physical disruption of the lipid bilayer. Additionally, we find substantial GO-induced oxidation of glutathione, a model intracellular antioxidant, paired with limited generation of reactive oxygen species, suggesting that oxidation occurs through a direct electrontransfer mechanism. These physical and chemical mechanisms both require nanosheet penetration of the cell membrane, suggesting that the enhanced antibacterial activity of the film with vertically aligned GO stems from an increased density of edges with a preferential orientation for membrane disruption. The importance of nanosheet penetration for cytotoxicity has direct implications for the design of engineering surfaces using GBNs.

Low-back pain is the number one cause of disability in the world, with mechanical loading as one of the major risk factors. Exoskeletons have been introduced in the workplace to reduce low back loading. During static forward bending, exoskeletons have been shown to reduce back muscle activity by 10% to 40%. However, effects during dynamic lifting are not well documented. Relative support of the exoskeleton might be smaller in lifting compared to static bending due to higher peak loads. In addition, exoskeletons might also result in changes in lifting behavior, which in turn could affect low back loading. The present study investigated the effect of a passive exoskeleton on peak compression forces, moments, muscle activity and kinematics during symmetric lifting. Two types (LOW and HIGH) of the device, which generate peak support moments at large and moderate flexion angles, respectively, were tested during lifts from knee and ankle height from a near and far horizontal position, with a load of 10 kg. Both types of the trunk exoskeleton tested here reduced the peak L5S1 compression force by around 5–10% for lifts from the FAR position from both KNEE and ANKLE height. Subjects did adjust their lifting style when wearing the device with a 17% reduced peak trunk angular velocity and 5 degrees increased lumbar flexion, especially during ANKLE height lifts. In conclusion, the exoskeleton had a minor and varying effect on the peak L5S1 compression force with only significant differences in the FAR lifts.

In this study, the full free motion of the filament in vortex structures is numerically simulated, and the influence of model parameters and horizontal position on the propulsion efficiency of the filament is investigated. With the “data + physics” approach with the immersed boundary method and Random Forest (RF) method, an RF model is initially employed to screen 189 sets of numerical experiments using a minimal amount of flow field physical data to select experimental groups capable of generating vortex bands. The selected experimental groups are then used to complete numerical experiments, followed by the re-introduction of a minimal amount of data and the use of the RF model to identify the motion modes of the filament. The experimental results indicate that the stretching coefficient of the filament has a negative effect on the thrust coefficient when the filament is in the vortex. The thrust of the filament decreases with increasing horizontal distance. The RF model demonstrates excellent identification capabilities, correctly classifying the vortex street structure with only three sets of data from three test points, achieving a high accuracy rate of 95% in identifying the motion modes of the filament.