Regular Shape Research Articles

Seismic behavior of irregular shaped beam-column connections

This paper reports test results and numerical analysis of special-shaped beam-column connections based on a frame-shear wall structure. Four connections of 1/5 scale ratio were tested under constant axial force and reversed lateral load on the top of column. The experiment investigated the effect of steel reinforced concrete (SRC) beam, in-plane and out of-plane reinforced concrete (RC) wall on the connections’ seismic behavior. The failure modes, hysteresis curves, ductility, strength degradation and energy-dissipating capacity of test specimens are reported. The results indicated that test joints were susceptible to suffer more brittle failure caused by formation of plastic hinge on column, which is considered unfavorable compared to conventional joint with regular shape in earthquake resisting. Adding in-plane shear walls to the connection switched column failure to beam failure mode, and significantly improved the connection’s strength, stiffness and ductility. Finite element models were detailed established and validated through experiment data. Influence of parameters including axial load ratio, concrete strength grade, section area and steel ratio of upper column, transverse hoops volumetric, RC wall of two orthogonal directions on connection’s seismic behavior were studied through modeling results.

Novel acaricidal and growth-regulating activity of Aloe vera and Rheum rhabarbarum extracts and their oil/water nanoemulsions against the camel tick, Hyalomma dromedarii

Hyalomma dromedarii is an important tick species infesting livestock. This work evaluated the novel adulticidal, insect growth-regulating, and enzymatic efficacy of ethanol plant extracts of Aloe vera and Rheum rhabarbarum and their nanoemulsions against males and engorged females of the camel tick, H. dromedarii. The physicochemical properties of nanoemulsions were evaluated. The High-Performance Liquid Chromatography (HPLC) analyses indicated that the extracts contained polyphenols and flavonoids, which could enhance their acaricidal effect. Dynamic light scattering (DLS) of the nanoemulsions of A. vera and R. rhabarbarum were 196.7 and 291 nm, whereas their zeta potentials were − 29.1 and − 53.1 mV, respectively. Transmission electron microscope (TEM) indicated that nanoemulsions showed a regular spherical shape (less than 100 nm). Fifteen days post-treatment (PT) with 25%, the mortality% of A. vera and R. rhabarbarum were 88.5 and 96.2%, respectively. Five days PT, the median lethal concentration values of A. vera, R. rhabarbarum, and their nanoemulsions were 7.8, 7.1, 2.8, and 1.02%, respectively, and their toxicity indices were 91.02, 100, 36.4, and 100%, respectively. Their median lethal time values PT with 3.5% were 6.09, 5.09, 1.75, and 1.34 days, respectively. Nanoemulsions enhanced the efficacy of the crude extract 1–7 folds, 5 days PT, and accelerated their speed of killing ticks 2–4 times. The total protein and carbohydrates, Acetylcholinesterase, Alpha esterase, and Amylase were affected PT. The reproductive potential of engorged females was adversely impacted. In conclusion, the novel A. vera and R. rhabarbarum extracts were promising acaricides, and their nanoformulations enhanced their efficacies.

Impact of ball milling on physicochemical, structural, and functional properties of Moringa oleifera L. leaf powders

Physicochemical, thermal, and structural properties of ball milling (BM) of Moringa oleifera leaf powders (M.L) were examined. By superfine grinding, three samples with different particle sizes (PAS) were produced. Specific surface area (SSA), Bulk (BD), tap (TD) densities and water solubility index (WSI) significantly increased with the decrease of PAS, while the angle of repose (AR), water holding capacity (WHC) and oil holding capacity (OHC) decreased. Also, as PAS was reduced, the flowability enhanced as the carr index changed from fair to good and AR ameliorated. Scanning electron microscopic (SEM) pictures showed that M.L were ground so finely that the form of the particles changed, started to be a regular shape and the surface roughness decreased as PAS decreased. Differential scanning calorimetry (DSC) curves showed that peak temperature decreased with the decrescent PAS. In all samples, Fourier transform infrared spectroscopy (FT-IR) detected no new chemical functional groups. No variation was found in the crystallinity index (CI) of any of the X-ray diffraction (XRD) patterns for the BM samples, while crystal size decreased.

Preparing HNS/n-Al heat-resistant microspheres with enhanced combustion performance using droplet microfluidic technology

Reducing the formation of large carbon clusters during the combustion of energetic materials (EMs) and improving their comprehensive performance hold great significance. With fluororubber (F2604) as a binder, this study prepared HNS/n-Al microspheres with different n-Al contents (5%, 10%, and 15%) using droplet microfluidic technology. Then, it characterized and tested the morphology, particle size distribution, dispersibility, crystal structure, thermal properties, mechanical sensitivity, and combustion behavior of the microspheres. The results show that the prepared microspheres had regular shapes, uniform particle sizes, and excellent dispersibility and contained more homogeneous components than physically mixed samples. Furthermore, the microspheres retained the crystal structures of the raw materials, enjoying high safety performance. The thermal analysis shows that HNS/n-Al microspheres had high heat resistance (thermal decomposition temperature: over 354 °C) and that a higher n-Al content was associated with more thorough thermal decomposition reactions of HNS (HNS: 83%, HNS/n-Al: 84%, 86%, and 93%). The ignition experiments show that the HNS/n-Al microspheres possessed excellent and stable combustion performance, as evidenced by more complete combustion reactions and significantly elevated energy release efficiency. Therefore, it is expected to achieve high-energy and high-speed responses of carbon-rich EMs and promote their practical applications.

On the unsteady interactions between a sweeping jet and afterbody vortices

In this paper, a sweeping jet was applied to control the afterbody vortices behind a 30° slanted-base cylinder at a Reynolds number of 87 000. Phase-locked stereo particle image velocimetry measurements were conducted during a sweeping jet actuation cycle, and insights of the complex three-dimensional interaction process between the sweeping jet and the afterbody vortices have been obtained for the first time. It is found that in the near-field of the jet orifice (x/c < 0.3), the jet swings from side to side over the endplate between the afterbody vortex pair. An intersection between them around x/c = 0.3 causes the sweeping jet to take on a zigzag pattern as it propagates downstream along the slanted surface. From x/c = 0.6 onwards, the intensity of this interaction decreases as the afterbody vortices become detached from the base. Nevertheless, the sweeping jet continues invading the afterbody vortices from their inner side and pushes its way outwards from the underside of the afterbody vortices causing them to weaken further. Furthermore, the interaction between sweeping jets and afterbody vortices results in a cyclic variation in the circulation of afterbody vortices, which increases in magnitude at downstream locations. Except for the phases where a merger between the afterbody vortex and the sweeping occurs, a reduction in the circulation is observed. Finally, the level of interaction between sweeping jets and afterbody vortices intensifies as the strength of the sweeping jet increases resulting in the afterbody vortices being penetrated by the sweeping jet and their regular shape being momentarily destroyed.

Mechanical and biodegradability of porous PCL/PEG copolymer-reinforced cellulose nanofibers for soft tissue engineering applications.

The design and development of a new class of biomaterial has gained particular interest in producing polymer scaffold for biomedical applications. Mechanical properties, biological and controlling pores scaffold of the biomaterials are important factors to encourage cell growth and eventual tissue repair and regeneration. In this study, poly-ε-caprolactone (PCL) /polyethylene glycol (PEG) copolymer (80/20) incorporated with CNF scaffolds were made employing solvent casting and particulate leaching methods. Four mass percentages of CNF (1, 2.5, 5, and 10wt.%) were integrated into the copolymer through a silane coupling agent. Mechanical properties were determined using Tensile Tester data acquisition to investigate the effect of porosity, pore size, and CNF contents. Tensile strength obtained for PCL/PEG- 5wt.% CNF was 16MPa, which drastically decreased after creating a porous structure to 7.1MPa. The optimum parameters of the results were found to be 5wt.% for CNF, 240μm for pore size, and 83% for porosity. Scanning electron microscopy (SEM) micrograph reveals that consistent pore size and regular pore shape were accomplished after the addition of CNF-5wt.% into PCL/PEG. The results of mass loss of PCL/PEG reinforced-CNF 1% have clearly enhanced to double values compared with PCL/PEG copolymer and three times with PCL/PEG scaffold-CNF 1%. In addition, all PCL/PEG reinforced and scaffold- CNF were partially disintegrated under composting conditions confirming their biodegradable behavior. This also provides a possible solution for the end life of these biomaterials.

Measuring urban waterlogging depths from video images based on reference objects

AbstractCamera surveillance systems can record urban waterlogging processes. Objects with regular shapes and fixed sizes captured by the camera can be utilized to calculate urban waterlogging depths based on geometric principles. In this study, we propose a machine learning‐based method to measure urban waterlogging depths using wheels and traffic buckets captured in video images as reference objects. This method is validated through laboratory experiments and observed data. The results demonstrate that: (1) the urban waterlogging depths calculated using urban reference objects show high consistency with the observed water level data; (2) in the laboratory scenario, the probability of error within 3 cm for measurements based on the hub, tire, and traffic bucket are 99.07%, 99.38%, and 81.55%, respectively; (3) in the real‐world scenario, the probability of error within 3 cm for measurements based on car hubs and pickup truck hubs are 97.30% and 95.14%, respectively. In conclusion, urban waterlogging depths can be accurately measured using reference objects with regular shapes. The proposed method can help obtain waterlogging data with higher temporal and spatial resolution at lower economic costs, which is of great significance for urban flood control.

Preparation of Ribes nigrum L. polysaccharides-stabilized selenium nanoparticles for enhancement of the anti-glycation and α-glucosidase inhibitory activities

Seven kinds of selenium nanoparticles (RP-SeNPs) were prepared by using the polysaccharides extracted from Ribes nigrum L. (RP) as the stabilizer and dispersant. Among them, RP-SeNPs-1 (94.2 nm), RP-SeNPs-2 (101.2 nm) and RP-SeNPs-3 (107.6 nm) with relatively smaller mean particle size exhibited stronger α-glucosidase inhibitory activity than other RP-SeNPs (115.3–164.2 nm) and SeNPs (288.9 nm). Ultraviolet-visible spectrophotometry, Fourier transform-infrared, X-ray diffraction, energy dispersive X-ray and X-ray photoelectron spectroscopy analyses confirmed that SeNPs were ligated with RP to form nanocomposites and displayed amorphous form. Electron microscopy images revealed that RP-SeNPs-1 − RP-SeNPs-3 were regular shape spherical nanocomposites with much better dispersion than SeNPs. Compared with SeNPs, RP-SeNPs displayed relatively high thermal, storage, pH and salt ion stability. Moreover, RP-SeNPs-1–RP-SeNPs-3 showed significantly better anti-glycation and α-glucosidase inhibitory activity than SeNPs, especially RP-SeNPs-1 with the smallest particle size. Inhibitory kinetics analysis indicated that SeNPs and RP-SeNPs inhibited α-glucosidase with competitive type and reversible mechanism. In addition, the conformation of the α-glucosidase was changed after binding with the SeNPs and RP-SeNPs-1. Fluorescence quenching and isothermal titration calorimetry assays revealed that these two nanoparticles could interact with α-glucosidase to form non-fluorescent complexes through hydrogen bonding, and the formation was spontaneously driven by enthalpy.

The electrothermal color-changing fabric based on high-sensitivity thermochromic microcapsules

High sensitivity including low color hydrolysis and a narrow temperature range of color-changing is important to thermochromic microcapsules. However, it is a challenge for conventional ternary thermochromic systems to realize the fast change of colors. A new class of high-sensitivity microcapsules and electrothermal color-changing fabrics were designed and synthesized by introducing CNTs into thermochromic systems via microencapsulation and coating technology. The high sensitivity was attributed to the enhanced filler CNTs and binary core phase change materials (1-Tetradecanol/1-Octadecanol). Moreover, the dosage amount of CNTs, core-to-shell ratios, and particle size on the temperature sensitivity of microcapsules were investigated. From the results, the optimized microcapsules with regular spherical shape exhibited a narrow color-change temperature range of 30–35 ℃ and low color hydrolysis of 11 ℃. As the core wall ratio increased from 1:1–3:1, the color change temperature range of microcapsules became narrower and the color hydrolysis was lower. According to the phase change behaviors, thermochromic microcapsules with a melting enthalpy of 70.64 J/g performed a good thermal regulation capacity. Furthermore, the reversible thermochromic performance of obtained microcapsules remained stable through 500 thermal cycles, demonstrating excellent thermal cycling stability. Combining the obtained microcapsules and electrothermal fabrics, highly sensitive electro-thermochromic (ETC) fabrics by voltage were prepared. Under the supplied voltage of 6 V, the ETC fabrics exhibited outstanding cyclic electrothermal color-changing performance. This unique design concept for high-sensitivity ETC fabrics has great potential applications in personal thermal management, the cooling of electronic devices, visible displays, and so on.

A New Strategy for Consumption of Functional Lipids from Ericerus pela (Chavannes): Study on Microcapsules and Effervescent Tablets Containing Insect Wax-Derived Policosanol.

In this study, we addressed various challenges associated with the consumption of functional lipids from the Ericerus pela (Chavannes), including unfavorable taste, insolubility in water, difficulty in oral intake, low bioavailability, and low psychological acceptance. Our study focused on the microencapsulation of policosanol, the key active component of insect wax, which is a mixture of functional lipids secreted by the Ericerus pela (Chavannes). We developed two innovative policosanol products, microcapsules, and effervescent tablets, and optimized their preparation conditions. We successfully prepared microcapsules containing insect wax-derived policosanol using the spray-drying method. We achieved 92.09% microencapsulation efficiency and 61.67% powder yield under the following conditions: maltodextrin, starch sodium octenyl succinate, and (2-hydroxy)propyl-β-cyclodextrin (HPβCD) at a ratio of 1:1:1, core-to-wall materials at a ratio of 1:10, 15% solid content, spray dryer feed temperature at 60 °C, inlet air temperature at 140 °C, and hot-air flow rate at 0.5 m3/min. The microcapsules exhibited a regular spherical shape with a minimal water content (1.82%) and rapid dispersion in water (within 143.5 s). These microcapsules released policosanol rapidly in simulated stomach fluid. Moreover, effervescent tablets were prepared using the policosanol-containing microcapsules. The tablets showed low friability (0.32%), quick disintegration in water (within 99.5 s), and high bubble volume. The microcapsules and effervescent tablets developed in this study presented effective solutions to the insolubility of policosanol in water. These products were portable and offered customizable tastes to address the psychological discomfort related to insect-based foods, thus providing a novel strategy for the consumption and secondary processing of insect lipids.

The effect of Cr atoms: From non-stoichiometric Ge-Te to Cr2Ge2Te6

The traditional phase change material Ge-Te presents a large difference with Cr2Ge2Te6 (CrGT) in the phase change properties. Compared with Ge-Te, the two-dimensional van der Waals material CrGT presents a reversed resistance state, in which the crystalline phase is in a high-resistance state and the amorphous phase is in a low-resistance state. Nevertheless, there are some structural similarities between the two materials. CrGT may be regarded as the Cr doping of Ge-Te. It is necessary to investigate the evolution of the structure and phase change properties of Ge-Te to CrGT through Cr doping. In this study, phase change materials Ge40Te60 (GT) and CrGT were fabricated. Subsequently, a series of intermediate state films were fabricated by changing the Ge/Te/Cr cation-to-anion ratio. Surprisingly, the coexistence of the CrGT and GT phases was observed in all intermediate films. As a result, a gradual reversal in the resistance between the amorphous and crystalline states can be observed. Transmission electron microscopy experiments were also performed to characterize the grain growth and the phase separation. Unlike GT, CrGT island-like crystal grains usually have boundaries with regular shapes. The pure CrGT-based device exhibited an excellent device performance. This work may provide a useful guide for further application of the CrGT phase change material.

Nanoparticles Titanium Dioxide with Thymus vulgaris extract in preservation and prolong the shelf life of cheese

Cheese is considered a perishable food that is affected by microorganisms, and due to the properties of nanomaterials that have antimicrobial activity, they have been used synergistically with plant extracts in inhibiting the action of microorganisms that cause cheese spoilage. In this study, TiO2 (Titanium dioxide) nanoparticles were synthesized using Thymus vulgaris leaves extract (TVLE) . Atomic Force Microscopywas used to investigate Titanium dioxide/ TVLE nanoparticles characterize, which improved the regular spherical shape and granular distribution of nanoparticles with a particle size of 13 nm . The results showed that the minimum inhibitory concentration (MIC) of Titanium dioxide was at a concentration of 4 mg/ml and 80 mg/ml for TVLE, while it was 2 + 20 mg /ml for Titanium dioxide and TVLE .The inhibitory effect increased against Brucella melitensis recorded 12 mm when mixing Titanium dioxide and TVLE, compared with the inhibitory effect of Titanium dioxide, which recorded 10.5 mm and TVLE, with an inhibition diameter 8.1 mm. The effect of using titanium particles and thyme leaves’ extract was studied alone at a concentration of 4 mg/ml and 80 mg/ml and also when mixed in the microbial properties and pH of white soft cheese samples, which were prepared in the laboratory and contaminated with Brucella melitensis at refrigerated storage conditions (5Cº) for 21days. The effect of the synergism relationship between TiO2 / TVLE significantly reduced the total number of microorganisms in samples contaminated and uncontaminated with B. melitensis. Adding titanium dioxide and TVLE at concentrations of 4 and 80 mg/ml contributed significantly to maintaining the pH level during the storage period compared with the control group.

Influence of magnetic field on the physicochemical properties of water molecule under growing of cucumber plant in an arid region

This study highlights the potential impact of magnetic fields on water quality, which could have implications for plant growth and development. Theoretical estimates of changes in surface tension, pH, and some other properties due to passing water through a magnetic field for a certain period were experimentally validated in this study. Overall, the results revealed changes in the physicochemical properties of water after magnetic field application. In accordance, pH significantly (p < 0.05) increased from 2 to 2.25, from 4 to 4.5, from 6 to 6.45, from 7.3 to 7.8, and from 8 to 8.7 and except at pH10, which decreased from 10 to 9.7. In addition, the model developed in this study indicated that the change of electrical conductivity (EC) decreased from 9 to 6.11 dS m−1 with an increasing number of run flow through the magnetic field. The decline in EC can be described as follows: magnetically treated water contains fine colloidal molecules and electrolytic chemicals that respond to a magnetic field by enhancing their ability for precipitation, resulting in a fall in EC. Moreover, the Hardness values of recirculated water were decreased after magnetic field application. This corroborates the decline of calcium carbonate adhesion and surface tension values as increases in hydrogen bonding between protons and water molecules and changes in the distribution of molecules in magnetized water. As the internal electrical field grew and the hydration shells surrounding the constituent ions weakened, EC decreased. Lastly, by using an electronic microscope, observing the water in regular, such as regular hexagonal tree shape instead of random irregular shapes after magnetic field application, confirming that the magnetic field had a significant effect on the physical properties of water molecules. In conclusion, magnetic behavior may improve water quality, resulting in increased development and plant growth.

Ultrasound diagnosis and treatment of branchial cleft cyst and preoperative management.

The ultrasonic diagnosis of cervical and facial cystic masses, as well as cases of missed diagnosis and misdiagnosis, was examined, to improve the diagnosis of branchial cleft anomalies. A retrospective analysis was conducted on 17 patients with branchial cleft cyst anomalies, including 11 males and 6 females, aged 12-53years, with an average age of 33 ± 2years, were unilateral single. All patients who underwent an ultrasound examination and image storage for retrospective analysis, and both longitudinal and transverse sections were scanned to observe the shape, size, boundary, peripheral relationship, and blood flow signal of the masses. All cases were examined with an enhanced CT scan, and pathological reports were generated. Among the 17 cases of branchial cleft anomalies, 15 cases were branchial cleft cysts, while one case involved fistula formation and one case involved sinus tract formation. Based on the type of branchial cleft, the first, second, and third cysts were classified in 4, 12, and 1 case, respectively. The sensitivity rate and specificity of ultrasonic diagnosis were 14/17 (82.4%) and 4/6 (66.7%), respectively. Ultrasonic characteristic analysis for the masses can be found in simple cystic masses or hypoechoic masses, most of them are of a regular shape and have a distinct boundary, and almost no blood flow signal. All patients who were misdiagnosed exhibited blood flow signals, including 1 patient with an abundant blood flow signal, 1 patient suspected of having ectopic thyroid with an abnormal function due to the rat-tail sign, 2 patients misdiagnosed as local inflammatory focus, and 1 patient misdiagnosed with tuberculous lymphadenitis. Ultrasound has a detection rate of up to 100% for cervical and facial masses, providing a fundamental determination of lesion characteristics and specific guidance for preoperative diagnosis. If the blood flow signals can be identified and carefully considered their peripheral relationship, the diagnostic rate can be improved.

S3R: Shape and Semantics-Based Selective Regularization for Explainable Continual Segmentation Across Multiple Sites.

In clinical practice, it is desirable for medical image segmentation models to be able to continually learn on a sequential data stream from multiple sites, rather than a consolidated dataset, due to storage cost and privacy restrictions. However, when learning on a new site, existing methods struggle with a weak memorizability for previous sites with complex shape and semantic information, and a poor explainability for the memory consolidation process. In this work, we propose a novel Shape and Semantics-based Selective Regularization ( [Formula: see text]) method for explainable cross-site continual segmentation to maintain both shape and semantic knowledge of previously learned sites. Specifically, [Formula: see text] method adopts a selective regularization scheme to penalize changes of parameters with high Joint Shape and Semantics-based Importance (JSSI) weights, which are estimated based on the parameter sensitivity to shape properties and reliable semantics of the segmentation object. This helps to prevent the related shape and semantic knowledge from being forgotten. Moreover, we propose an Importance Activation Mapping (IAM) method for memory interpretation, which indicates the spatial support for important parameters to visualize the memorized content. We have extensively evaluated our method on prostate segmentation and optic cup and disc segmentation tasks. Our method outperforms other comparison methods in reducing model forgetting and increasing explainability. Our code is available at https://github.com/jingyzhang/S3R.

Meta-analysis of correlation between CT-based features and invasive properties of pure ground-glass nodules.

Several studies have revealed that computed tomography (CT) features can make a distinction in the invasive properties of pure ground-glass nodules (pGGNs). However, imaging parameters related to the invasive properties of pGGNs are unclear. This meta-analysis was designed to decipher the correlation between the invasiveness of pGGNs and CT-based features, and ultimately to be conducive to making rational clinical decisions. We searched a series of databases, including PubMed, Embase, Web of Science, Cochrane Library, Scopus, wanfang, CNKI, VIP, as well as CBM databases, until September 20, 2022, for the eligible publications only in Chinese or English. This meta-analysis was implemented with the Stata 16.0 software. Ultimately, 17 studies published between 2017 and 2022 were included. According to the meta-analysis, we observed a larger maximum size of lesions in invasive adenocarcinoma (IAC) versus that in preinvasive lesions (PIL) [SMD=1.37, 95% CI (1.07-1.68), P<0.05]. Meanwhile, there were also increased mean CT values of IAC [SMD=0.71, 95% CI (0.35, 1.07), P<0.05], the incidence of pleural traction sign [OR=1.94, 95% CI (1.24, 3.03), P<0.05], the incidence of IAC spiculation [OR=1.55, 95% CI (1.05, 2.29), P<0.05] in comparison to those of PIL. Nevertheless, IAC and PIL exhibited no significant differences in vacuole sign, air bronchogram, regular shape, lobulation and vascular convergence sign (all P>0.05). Therefore, IAC and PIL manifested different CT features of pGGNs. The maximum diameter of lesions, mean CT value, pleural traction sign and spiculation are important indicators to distinguish IAC and PIL. Reasonable use of these features can be helpful to the treatment of pGGNs.

Identification of Bubble Nebulae around NGC 55 ULX-1 with MUSE Observations

Using the Multi Unit Spectroscopic Explorer (MUSE) instrument on the Very Large Telescope, we identified three bubble nebulae (denoted as A, B, and C) around an ultraluminous X-ray source (ULX) in NGC 55. Bubble A shows a regular elliptical shape surrounding the ULX, with a morphology similar to the canonical ULX bubble around NGC 1313 X-2. It is most likely inflated by the ULX disk wind with a mechanical power close to 1039 erg s−1. Bubble B lies 11″ away from the ULX on the sky plane and is not contiguous to Bubble A. It displays a bow-shock-like morphology, and is likely driven by a collimated dark jet from the ULX with a mechanical power of about 3 × 1038 erg s−1. If this scenario is correct, we predict that Bubble B should present radio emission with a flux of about 1–102 μJy at 5 GHz. Bubble C appears within Bubble A, with a velocity and velocity dispersion distinct from the rest of Bubble A. Its nature is unclear and could be part of Bubble A as a result of low local density. The optical counterpart of ULX-1 exhibits broad Hα, consistent with emission from a hot disk wind.

TiN Inclusions Formation in Ti-Al Deoxidized Ultra-low Carbon Steel

TiN inclusion in steel is easy to cause surface defects in ultra-low carbon steel. TiN was studied by analyzing their formation mechanisms, compositions, and morphology through SEM (scanning electron microscope) and EDS (energy-dispersive X-ray spectroscopy). Thermodynamic analysis through kinetic simulations of the different stages of RH degassing was conducted by the FactSageTM software package. TiN inclusions can distribute either randomly or in clusters with exogenous inclusions. Most of the TiN inclusions are regular cubic shapes. Some of them have a black center which is alumina inclusion. The alumina inclusions formed by reoxidation can catch TiN inclusions and combine with them because of the strong combining affinity between them. Ti is a strong nitride former in liquid steel, and TiN mostly forms during cooling or solidification. The maximum temperature is approximately 1, 430 °C. The growth of TiN inclusions can be controlled by adjusting the Ti and N contents (N< 30 ppm).

Water-augmented vaporizing foil actuator welding: Process performance and mechanisms clarifications

This paper proposes a novel impact welding method named water-augmented vaporizing foil actuator welding, in which liquid water is introduced to alter the foil’s vaporization process, thus altering the induced driving pressure and the final welding performance. A series of comparative experiments were performed to confirm the effectiveness of the process and to understand the underlying mechanism. The proposed process decreased the lower-bound required discharge energy by 58–69%, increased the peel strength by 30–60%, and significantly reduced the variability in the critical standoff distance at the lower bound of the weld window. In addition, the proposed process resolved the robustness issue by producing a much more regular and repeatable shape of the weld area compared to conventional VFAW. Furthermore, three potential mechanisms have been proposed to explain the process improvement: the added water 1) increased the electrical energy deposition, 2) introduced additional energy from the aluminum-water chemical reaction, and 3) provided a more efficient force-transfer medium. In summary, this paper introduces a novel impact welding method with much improved process capability and robustness compared to conventional vaporizing foil actuator welding. In addition, due to its simplicity, this method may be easily extended for other forms of impulse metalworking, which may stimulate a wide interest for the community of high velocity metalworking.

Polyhedral Colloidal Clusters Assembled from Amphiphilic Nanoparticles in Deformable Droplets.

Polyhedral colloidal clusters assembled from functional inorganic nanoparticles have attracted great interest in both scientific research and applications. However, the spontaneous assembly of colloidal nanoparticles into polyhedral clusters with regular shape and tunable structures remains a grand challenges. Here, we successfully construct Mackay icosahedral and regular tetrahedral colloidal clusters assembled from gold nanoparticles grafted with a mixture of polystyrene (PS) and poly(2-vinylpyridine) (P2VP) homopolymers by precisely tuning the interfacial interaction between the nanoparticles and the oil/water interface. By increasing the proportion of hydrophilic P2VP ligands on the surface of gold nanoparticles, the Mackay icosahedral clusters can transform into regular tetrahedral clusters in order to maximize the surface area of the polyhedral assembly. Furthermore, we reveal the formation mechanism of these regular polyhedral colloidal clusters. The formation of polyhedral colloidal clusters is not only dependent on the entropy but also determined by the interfacial free energy. This finding demonstrates an effective approach to organize nanoparticles into polyhedral colloidal clusters with potential applications in various fields.