Uniform Rod Research Articles

Microstructure and properties of Cu-doped β-Ga2O3 rod prepared with liquid metallic gallium

One-dimensional β-Ga2O3 is expected for potential applications in electronics, sensors, and optoelectronics. Gallium hydroxide (GaO(OH)) with different Cu doping was prepared via the hydrothermal method using liquid metallic gallium and copper chloride dihydrate (CuCl2·2H2O) as the starting materials. The material was then transformed to β-Ga2O3 after calcination at 800 °C. SEM images reveal that the obtained powders are well dispersed and have a uniform rod morphology with a length of 13–14 μm and a width of approximately 500 nm. The addition of Cu ion significantly improves the surface morphology of the rod and effectively inhibits the generation of intrinsic oxygen vacancies. And the relative Fermi energy level of Cu-doped β-Ga2O3 undergoes a notable shift from 2.81 eV to 1.25 eV, suggesting the formation of p-type conductivity. Meanwhile, the PL spectra of the Cu-doped samples exhibit emission peaks in the red wavelength range, which is expected for new applications.

An Efficient Progressive Grid Generation Method Considering Internal Quality and Boundary Grid Adjustment

Due to its elegant appearance and high structural efficiency, free-form grid structures are increasingly adopted in architectural design. However, it is a challenging task for engineers to generate a uniform and well-shaped grid on a free-form surface while considering the processing of both interior and boundary of grid, especially for composite surfaces. To generate well-shaped grids with uniform rods, regular cells and smooth visual effects over free-form surfaces, this paper develops an innovative triangular grid generation method capable of automatically managing grid boundary with extending initial surface. In the method, nodes of grid structure are considered to be zero mass particles and are progressively added to the extended surface from geometric center to the boundary of surface. A boundary-processing algorithm is then established to evenly distribute nodes on initial boundary curve, while ensuring that grid cells at the boundary do not exhibit elongation. A mechanical simulation system based on spring-mass model is improved to optimize spatial grid structure, rods of grid are regarded as linear springs, a surface attraction force and an anchoring force are performed on grid nodes. Moreover, the proposed method allows architects change grid direction and rods length easily, which can greatly improve the efficiency of design. Several case studies show that the method can effectively avoid distortion of grids and generate well-shaped grids that can meet aesthetic requirements.

Drag of Rankine bodies embedded in porous media at small Darcy numbers

This paper studies the flow over a solid inclusion embedded in a porous medium of low permeability. We study Rankine bodies which represent circular cylinders and spheres when the aspect ratio is one, and thin plates and almost uniform rods when the aspect ratio is small. Using boundary layer theory, the flow field and pressure distribution are determined. It is found that the pressure drag dominates the shear drag except for small aspect ratios. Thus, geometry plays a decisive role in the choice of using the Darcy equation or the Darcy-Brinkman equation. The results are important for the determination of flow resistance of a non-homogeneous porous medium which has solid inclusions.

Rod-Shaped Mesoporous Zinc-Containing Bioactive Glass Nanoparticles: Structural, Physico-Chemical, Antioxidant, and Immuno-Regulation Properties.

Bioactive glass nanoparticles (BGNs) are applied widely in tissue regeneration. Varied micro/nanostructures and components of BGNs have been designed for different applications. In the present study, nanorod-shaped mesoporous zinc-containing bioactive glass nanoparticles (ZnRBGNs) were designed and developed to form the bioactive content of composite materials for hard/soft tissue repair and regeneration. The nanostructure and components of the ZnRBGNs were characterized, as were their cytocompatibility and radical-scavenging activity in the presence/absence of cells and their ability to modulate macrophage polarization. The ZnRBGNs possessed a uniform rod shape (length ≈ 500 nm; width ≈ 150 nm) with a mesoporous structure (diameter ≈ 2.4 nm). The leaching liquid of the nanorods at a concentration below 0.5 mg/mL resulted in no cytotoxicity. More significant improvements in the antioxidant and M1-polarization-inhibiting effects and the promotion of M2 polarization were found when culturing the cells with the ZnRBGNs compared to when culturing them with the RBGNs. The doping of the Zn element in RBGNs may lead to improved antioxidant and anti-inflammatory effects, which may be beneficial in tissue regeneration/repair.

Iterative suppression of Kerr-induced instabilities in Bessel beams using on-axis intensity shaping

Kerr-induced instabilities in zeroth-order Bessel beams with low focusing angle prevent the formation of longitudinally uniform plasma rods in the filamentation regime. These instabilities lead to the oscillation of the beam on-axis intensity via the generation of new spatial frequencies by a first stage of spectral broadening followed by a second stage of four-wave mixing. Here, we numerically demonstrate an efficient approach to drastically reduce the instabilities due to the second stage. It is based on shaping the longitudinal intensity profile with spatio-spectral components in opposition of phase to the Kerr-generated ones via an iterative approach. Zeroth-order Bessel beams with a longitudinal flat intensity plateau can be generated in a few iterations in the nonlinear regime. This is performed in both monochromatic and pulsed femtosecond regimes.

Uniform Colloidal Polymer Rods by Stabilizer-Assisted Liquid-Crystallization-Driven Self-Assembly.

The synthesis of anisotropic colloidal building blocks is essential for their self-assembly into hierarchical materials. Here, a highly efficient stabilizer-assisted liquid-crystallization-driven self-assembly (SA-LCDSA) strategy was developed to achieve monodisperse colloidal polymer rods. This strategy does not require the use of block copolymers, but only homopolymers or random copolymers. The resulting rods have tunable size and aspect ratios, as well as well-defined columnar liquid crystal structures. The integrated triphenylene units enable the rods to exhibit unusual photo-induced fluorescence enhancement and accompanying irradiation memory effect, which, as demonstrated, are attractive for information encryption/decryption of paper documents. In particular, unwanted document decryption during delivery can be examined by fluorescence kinetics. This SA-LCDSA-based approach can be extended to synthesize other functional particles with desired π-molecular units.

DESIGN OF SHELL CONJUNCTION ZONES IN PRESSURE VESSELS

Separation forces occur in shell junctions of fuel tanks due to the change in its geometry. To compensate the forces, thrust rings are placed in these zones. Moreover, there is a necessity to determine a form and dimensions of the trust ring cross section with consideration of the operation conditions. Welding is used to join trust rings with a shell in case of conventional manufacturing. Nowadays, additive manufacturing technology is constantly being developed. Additive method allows to create objects with various geometry, in a layer-by-layer way of addition of the material in accordance with a computer model. These new technological capabilities make the task of determining of the geometry of the fuel tank in the shell’s junctions zone actual. 
 The following work provides a consideration of two approaches to the determination of the conversion geometry of shells in-between area instead of trust ring. The first approach is based on determination of a median surface with the use of rational cubic splines and membrane theory of shells. The second approach is based on the use of topology optimization of the initial design. The choice of the first approach relates to the fact that standard energy functional like potential energy of uniform bent rod or uniform sheet can be described with cubic splines. In the following work the use of rational cubical splines for build-up a transitive area in a junction zone of the spherical-conical vessel is considered. Spline parameters are determined based on the condition of median surface propagation of the transitive zone in its probable location. Thickness of the shell in the transitive area was evaluated due to the membrane theory of shells with the use of Huber von Mises Hencky theory of failure. Obtained solutions are tested in numerical models of spherical-conical vessel. Comparison of two approaches is carried out and practical recommendations are given.

Application of Mangrove Timber in Reinforcing Concrete

Use of mangrove timber beams for supporting floor slabs in historic buildings in Zanzibar Stone Town is still applied although the available structural data on mangrove timber is inadequate. This concern has called for an investigation on the structural properties of mangrove timber, so that the information obtained could help to establish the structural strength of the existing floor slabs in historic buildings. Hence, mangrove timber specimens were sampled from Zanzibar, and tested in the laboratory for their strengths in tension, compression and shear. The test results showed that mangrove is a hardwood timber of strength class D70, the highest rank of timber classification. Also, concrete beam specimens reinforced with mangrove timber rods, and others reinforced with structural steel were studied. The obtained test results showed that beams reinforced with mangrove timber rods with enlarged ends performed better than those reinforced with uniform mangrove rods. The strength of the beams reinforced with mangrove timber was found to be 50% of the beams reinforced with steel bars, implying that mangrove timber can be used to reinforce concrete beams.

Tailing copper cobalt sulfide particle-decorated tube-like structure as efficient active material of battery supercapacitor hybrid

Copper cobalt sulfide (CuCo2S4) has received intensive attentions as one of effective battery-type materials of battery supercapacitor hybrids (BSH), because of numerous redox states and large conductivity. Morphology has been widely reported to play important roles on energy storage ability. Tube-like structure is beneficial for providing large surface area at inner/outer surface, and efficient charge transfer paths in one-dimensional directions. In this study, the CuCo2S4 particle-decorated tube-like structure is firstly designed on nickel foam via the hydrothermal process at different temperatures. The effects on morphology, composition and electrochemical performance are examined. The CuCo2S4 synthesized at 160 °C shows the most uniform rod size and regularly distributed particles on surface. The highest specific capacitance (CF) of 831.7 F/g corresponding to the capacity of 115.6 mAh/g is achieved for the optimal CuCo2S4 electrode, due to the largest electrochemical surface area with multiple active sites. A BSH is fabricated by using the CuCo2S4 positive electrode and the activated carbon negative electrode. A wide potential window of 1.5 V and the maximum energy density of 32.1 Wh/kg at power density of 1.1 kW/kg are achieved. The CF retention of 78.8% and Coulombic efficiency of 95.5% are also attained after 10,000 charge/discharge cycles for the BSH.

Compact aerial ultrasonic source integrating the transverse vibration part with the bolt-clamped Langevin transducer

We have previously developed a compact circular vibrating plate aerial ultrasonic source with a grooved uniform rod that can produce a large vibration displacement by using piston vibration and emit intense sound waves perpendicular to the vibration surface. In this paper, to create a compact ultrasonic source that can radiate intense aerial ultrasonic waves, we produced a compact aerial ultrasonic source integrating the transverse vibration part with a bolt-clamped Langevin transducer and we investigated the sound source characteristics. These results demonstrated that compared with a conventional source, the length of our source was shorter, the sound pressure was higher, and its structure was simpler.

Spongy TiO2 layers deposited by gig-lox sputtering processes: Contact angle measurements

The use of nanostructured materials is increasingly widespread thanks to their particular properties that can improve the performance of devices in various scientific applications. One of them is in the architecture of perovskite solar cells characterized by high photoconversion efficiency values that make them able to compete with silicon solar cells. In this framework, we deposited TiO2 sponges by reactive sputtering based on a grazing-incidence geometry combined with the local oxidation of species. The deposited material gains 50% porosity in volume through depths of hundreds of nanometers and consists of a forest of uniform rods separated by mesopores (pipelines) arising from the grazing geometry. Many previous studies showed how TiO2 can improve the efficiency of perovskite solar cells. In this article, we investigated the change of the wettability values of the TiO2 samples before and after a postdeposition thermal annealing treatment. For comparison, the influence of the annealing on the wettability of the glass substrate is also reported.

Cerium-iron phosphate nano flower bifunctional electrocatalyst for efficient electrochemical detection and catalytic reduction of hazardous 4-nitrophenol

Since 4-nitrophenol (4-NP) is a high-priority hazardous contaminant that can harm humans, animals, and plants, detecting and determining its presence in the environment is an issue of utmost importance. This study was focused on the electrochemical detection of 4-NP using a cerium-iron phosphate electrode modified on a glassy carbon electrode (CeFeP/GC). X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction, and X-ray photoelectron spectroscopy confirmed the formation of CeFeP. TEM analysis reveals that CeFeP formation is a flower-like morphology comprising several uniform rods. As synthesized, flower-like CeFeP catalyst was used for excellent bifunctional electrochemical detection and reduction of toxic 4-NP. Cyclic voltammetry and differential pulse voltammetry (DPV) were performed to analyze the stepwise electrode-modification process. The CeFeP/GC electrode displayed a higher cathodic current response at a low potential of − 0.44 V for 4-NP detection. At optimized conditions, CeFeP/GC electrode showed a wide range sensitivity of 0.1–50 μM with a limit of detection (LOD) of 0.01 μM. Additionally, the CeFeP catalyst was employed for the catalytic degradation of 4-NP and exhibited excellent catalytic activity towards 4NP- reduction. The proposed catalyst completes the reduction reaction within 11 min. The proposed bifunctional electrocatalyst is a very useful, inexpensive, and novel sensor platform with considerable potential for environmental applications

Dynamics of longitudinal impact in uniform and composite rods with effects of various support conditions

A finite element formulation is developed in this paper to analyze impact-induced waves in a rod collide with a striking mass. The formulation is established based on St. Venant's contact theory. Effects of mass ratios and boundary conditions, whether fixed, free, or elastic, are investigated. Both uniform rods and composite rods are considered. A shortcoming in traditional finite element models is to consider the rod and the struck mass as separate identities that gives inaccurate results for the discontinuity at the arrival of the impact wave. Instead, the proposed model considers the rod and the struck mass as one system that gives extremely accurate corresponding results. Wave propagation, transmission, and reflection from the constraint end and at the discontinuous interface are thoroughly analyzed. Succession collision that may occur between the struck mass and the rod is also investigated. Whenever it is possible, the finite element results are compared with analytical solutions. The analytical solutions are obtained with either the direct mode superposition method (DMSM) or wave theory. The proposed model can be used to model many systems that are subjected to longitudinal impact loadings and for crack detection. The model has the potential to be extended to perform simulation and analysis for many practical applications, like nanostructures under impact loads.

Galvanostatic Li Electrodeposition in LiTFSI-PC Electrolyte: Part I. Effects of Current Density in Initial Stage

Galvanostatic electrodeposition of Li was carried out in 1 M LiTFSI/PC electrolyte to investigate the effect of current density on the morphological variations during the initial stage of the electrodeposition. The solid electrolyte interphase (SEI) formation process was analyzed from the potential change combined with XPS and UPS measurements along with SEM observation of Li deposits. A significant difference in the deposited Li morphology was observed depending on the current density. The simultaneous growth of whisker-like and granular deposits was noticed at lower current density, while the experiments at higher current densities evolved rather uniform mesoscopic-sized rod development. The formation behavior of SEI prior to Li deposition also differed between lower and higher current densities, of which the transition was about 4 mA cm−2. It was deduced that the formation history of SEI affected the surface defect density heterogeneity and mass transport properties inside SEI. The event of “sprouting,” in which Li precipitates nucleated and grown in SEI are extruded from the SEI layer into the electrolyte, certainly influenced the subsequent growth mode. The diffusion coefficient of Li+ in the SEI galvanostatically formed on Ni substrate in 1 M LiTFSI/PC was estimated to be in the order of 10−9 cm2 s−1.

Synthesis of Uniform Size Rutile TiO2 Microrods by Simple Molten-Salt Method and Its Photoluminescence Activity.

Uniform-size rutile TiO2 microrods were synthesized by simple molten-salt method with sodium chloride as reacting medium and different kinds of sodium phosphate salts as growth control additives to control the one-dimensional (1-D) crystal growth of particles. The effect of rutile and anatase ratios as a precursor was monitored for rod growth formation. Apart from uniform rod growth study, optical properties of rutile microrods were observed by UV−visible and photoluminescence (PL) spectroscopy. TiO2 materials with anatase and rutile phase show PL emission due to self-trapped exciton. It has been observed that synthesized rutile TiO2 rods show various PL emission peaks in the range of 400 to 900 nm for 355 nm excitation wavelengths. All PL emission appeared due to the oxygen vacancy present inside rutile TiO2 rods. The observed PL near the IR range (785 and 825 nm) was due to the formation of a self-trapped hole near to the surface of (110) which is the preferred orientation plane of synthesized rutile TiO2 microrods.

Design, Cytotoxicity, and Tumor Targeted Drug Delivery of 5Fluorouracil Encapsulated in pH-Sensitive Co-polymers GG-g-P (HEMA) Conjugate Riboflavin Thin-Film

The study finds the design, cytotoxicity, and tumor-targeted drug delivery of 5Fluorouracil encapsulated in pH-sensitive guar gum grafted polymer. Cancer targeting 5FU loaded GG grafted p(HEMA) conjugated riboflavin thin-film (GG-g-P(HEMA)-RF) was successfully fabricated from guar gum, 2-hydroxy ethyl methacrylate, and riboflavin targeting agents using N, N-methylene bis acrylamide as a crosslinking agent in the presence of tetramethylethylenediamminne (TEMED) initiator Ammonium persulfate act as a catalyst. FT-IR and XRD spectroscopy techniques were used to analyze the structural features of the GG-g-P(HEMA)-RF. The results of SEM revealed that the carrier is of uniform rod shape, with a low porosity index and outstanding performance in phrases of 5FU encapsulation and extended-release ability. Targeted drug delivery strategies have received special attention from the scientific world due to advantages such as more effective therapy and reduction of side effects. Cytotoxicity effects of 5FU loaded GG-g-P(HEMA)-RF against Ehrlich Ascites Carcinoma (EAC) cells in vitro were investigated at different concentrations (0, 25, 50, 100, and 150 μg/mL) using trypan blue exclusion assay. The MTT cytotoxic assay investigated cell viability against EAC experimental models and implied the excellent biocompatibility of the carrier. The results revealed the anti-proliferative effect along with molecular signaling of apoptosis and generated reactive oxygen species (ROS) in Ehrlich Ascites Carcinoma cell lines. The morphological changes of apoptosis were evident in EAC cells and were observed using optical microscopy after staining. DPPH free radical scavenging assay was carried out to determine the radical scavenging activity of the 5FU loaded and unloaded GG-g-P(HEMA)-RF. The 5FU loaded GG-g-P(HEMA)-RF with DNA interaction was examined by electronic and spectroscopic fluorescence methods.

Numerical investigation of geometrically nonlinear clamped uniform rods and rods with sections varying exponentially free vibration

The present paper is intended to investigate the problem of linear and non-linear longitudinal free vibration of uniform rods and rods whose cross-sections vary exponentially at large vibration amplitudes. The method adopted consists in discretizing the energy term on linear kij and non-linear rigidity tensor bijkl, as well as the mass tensor mij. Therefore, the formulation of this structure is based on Lagrange equations and the harmonic balance method so as to obtain the nonlinear algebraic equations. These latter are solved numerically and analytically through the explicit and linearized method. The response of Clamped-Clamped uniform and non-uniform rods on our structure are highlighted in the amplitude frequency and associated first three mode shapes. Moreover, this research leads to study the influence of the exponential slope on the maximum displacement, thus emphasizing the non-uniform bars usefulness. The obtained results are then compared with the available literature with a view to validating this theory. As a perspective, the method used in this paper would be pushed to study the FDM material, taking into account other parameters related to additive manufacturing, and later to be validated experimentally. Longitudinal vibrations are important in mechanical structures; therefore, the determination of their dynamic behaviour needs to be understood. In the present study, the effect of the displacement amplitude on the exponential slope of the structure was analysed, which led to the determination of the reduction range of the vibration amplitude under resonance. However, this should be taken into account in the design process. Besides, the usefulness of the non-linearity geometric effects was demonstrated to examine these structures by considering all the parameters involved. A linearized procedure is used to solve a nonlinear algebra equation. The use of this method leads to reduce calculation time contrary to iterative methods.

An approach for recovering initial temperature via a bounded linear time sampling

We have improved the results of DeVore and Zuazua's work in [6] and addressed some questions posed in their paper. By constructing a linearly growing finitely many future times in a bounded interval, we have improved their result of recovering initial temperature profile from known temperature measurements at a fixed location of a body and at finitely many later times. More explicitly, we have constructed a finitely many times with a linear growth in a bounded interval such that the temperature measurements taken at a fixed location of a thin uniform homogeneous rod of length π and at these finite time instances lead to a recovery of the initial temperature profile with a desired accuracy provided the initial temperature is in a suitable closed subset of L2[0,π].

Fabrication of pH responsive FU@Eu-MOF nanoscale metal organic frameworks for lung cancer therapy

Fabrication of biocompatible drug delivery systems (DDS) with enhanced permeation -retention effect and precise targeting is a major challenge in cancer therapy. The present study focused on fabrication of europium metal-organic framework (EuMOF) as pH responsive drug delivery system for sea weed polysaccharide fucoidan (FU@Eu-MOF) by one-pot synthesis method and assess its anticancer potential against lung cancer. Fabricated Eu-MOF exhibited high drug loading efficiency (22.15% by wt) and pH responsive controlled release of drug fucoidan (85.3 ± 0.02% in 48 h at pH 5.0). Material characterization revealed the formation of monodispersed uniform rod shaped structure decorated with fucoidan on the surface with average particle size of 71 ± 0.21 nm. Results of anticancer studies revealed that FU@Eu-MOF showed enhanced anticancer potential (IC50 value 32.17 ± 0.06 μg/ml) in lung cancer cells (A549) when compared to fucoidan alone (IC50 60.34 ± 0.03 μg/ml). Mechanism of anticancer potential revealed that FU@Eu-MOF enhanced ROS level inducing mitochondrial dysfunction and DNA damage leading to apoptosis. Safety evaluation studies revealed that FU@Eu-MOF showed neither cytotoxic, nor hemolytic activity under in vitro condition. To conclude the results of the study reveals FU@Eu-MOF as promising biocompatible material for drug delivery system for lung cancer therapy and other biomedical applications.

Hydrochloric acid-mediated synthesis of ZnFe2O4 small particle decorated one-dimensional Perylene Diimide S-scheme heterojunction with excellent photocatalytic ability

The recyclable and stable ZnFe2O4 small particle decorated one-dimensional perylene diimide (PDI) S-scheme heterojunction (1D PDI/ZnFe2O4) is prepared by the hydrochloric acid-mediated (HCl-mediated) strategy, interestingly, the morphology of the 1D PDI/ZnFe2O4 can also be effectively regulated by HCl-mediated process, the existence of HCl can regulate PDI into a uniform rod structure, while the co-existence of HCl and PDI can limit ZnFe2O4 to become the uniform small particles. More importantly, based on the 1D rod structure of PDI and the small size effect of ZnFe2O4, carriers can migrate to the surface more easily, which can improve the photocatalytic activity. Meanwhile, due to the appropriate energy level structure, the S-scheme heterojunction structure is formed between PDI and ZnFe2O4, which eliminates meaningless photo-generated charge carriers through recombination and introduces strong redox to further enhance the photodegradation effect, thereby, 1D PDI/ZnFe2O4 exhibits excellent photocatalytic ability, under the visible light irradiation, the degradation rate of tetracycline (TC) with 1D PDI/ZnFe2O4 (66.67%) is 9.18 times that with PDI (7.26%) and 9.73 times that with ZnFe2O4 (6.85%). This work proposes new ideas for the assembly of magnetic organic-inorganic S-scheme heterojunction photocatalysts.