Shape Modification Research Articles

An Investigation of Charm Quark Jet Spectrum and Shape Modifications in Au+Au Collisions at \(\sqrt {s_{NN}} = 200\) GeV

An Investigation of Charm Quark Jet Spectrum and Shape Modifications in Au+Au Collisions at \(\sqrt {s_{NN}} = 200\) GeV

Improvement of undulator radiation intensity using edge radiation

The intensification of undulator radiation caused by the application of edge radiation due to a relativistic electron passing through a straight section is analytically and numerically investigated. Here, the modification of the undulator orbit shape of the cosine wave function to a triangular wave function is shown to increase the peak radiation for an undulator. The principle of the intensification effect is based on the superimposition of the edge radiation field from tilted straight sections, which create the triangular wave orbit. The tilt angles for the straight sections have values of rad for the longitudinal axis of the undulator, where is a relativistic factor. The longitudinal length of a straight section has a value of for a radiation wavelength Using a simple model, an analytical equation for the radiation intensity for an undulator with a triangular orbit is derived. The results obtained using the equation are in agreement with those obtained using a numerical radiation code. The peak radiation intensity is estimated to be about two times larger than that of an ordinary planar undulator with K = 1 and the same longitudinal length.

Machine Learning Applied to EIT: Image Reconstruction, Displaced Electrodes and Boundary Shape

Electrical Impedance Tomography (EIT) is a noninvasive, nonradioactive technique used to obtain an internal image of a body or object. This work addresses several EIT-related problems using Artificial Neural Networks (ANNs). The EIT method consists of performing measurements of electrical potentials in a set of electrodes while different patterns of electrical current are applied. This work proposes the use of a modified version of LeNet-5 to determine the conductivity distribution within the domain, resulting in an image of the interior of the boundary in which the electrodes are positioned. There are two sources of errors in the usage of EIT in medical images. The first one is the displacement of the electrodes, which are supposed to be equidistant; and the second one is the modification of the boundary shape. The human body is not rigid, and due to breathing the boundary shape changes, leading to the displacement of electrodes. A modified version of LeNet-5 is also used to determine the changes of the boundary shape, and classifiers, such as Support Vector Machine (SVM), Random Forest and K-nearest Neighbors (KNN), are used to determine the displaced electrodes. In this work, all methods are used apart. Then, the reconstruction algorithm does not yet consider these sources of errors.

Probe the nanoparticle-nucleus interaction via coarse-grained molecular model.

The present study reports on a computational model that systematically evaluates the effect of physical factors, including size, surface modification, and rigidity, on the nuclear uptake of nanoparticles (NPs). The NP-nucleus interaction is a crucial factor in biomedical applications such as drug delivery and cellular imaging. While experimental studies have provided evidence for the influence of size, shape, and surface modification on nuclear uptake, theoretical investigations on how these physical factors affect the entrance of NPs through the nuclear pore are lacking. Our results demonstrate that larger NPs require a higher amount of energy to enter the nucleus compared to smaller NPs. This highlights the importance of size as a critical factor in NP design for nuclear uptake. Additionally, surface modification of NPs can impact the nuclear uptake pathway, indicating the potential for tailored NP design for specific applications. Notably, our findings also reveal that the rigidity of NPs has a significant effect on the transport process. The interplay between physicochemical properties and nuclear pore is found to determine nuclear uptake efficiency. Taken together, our study provides new insights into the design of NPs for precise and controllable NP-nucleus interaction, with potential implications for the development of efficient and targeted drug delivery systems and imaging agents.

Knowledge-Based Design of Multifunctional Polymeric Nanoparticles.

Conventional drug delivery systems (DDS) today still face several drawbacks and obstacles. High total doses of active pharmaceutical ingredients (API) are often difficult or impossible to deliver due to poor solubility of the API or undesired clearance from the body caused by strong interactions with plasma proteins. In addition, high doses lead to a high overall body burden, in particular if they cannot be delivered specifically to the target site. Therefore, modern DDS must not only be able to deliver a dose into the body, but should also overcome the hurdles mentioned above as examples. One of these promising devices are polymeric nanoparticles, which can encapsulate a wide range of APIs despite having different physicochemical properties. Most importantly, polymeric nanoparticles are tunable to obtain tailored systems for each application. This can already be achieved via the starting material, the polymer, by incorporating, e.g., functional groups. This enables the particle properties to be influenced not only specifically in terms of their interactions with APIs, but also in terms of their general properties such as size, degradability, and surface properties. In particular, the combination of size, shape, and surface modification allows polymeric nanoparticles to be used not only as a simple drug delivery device, but also to achieve targeting. This chapter discusses to what extent polymers can be designed to form defined nanoparticles and how their properties affect their performance.

The Study of the Profile Errors of Straight Teethed Shaper Cutters in the CAD-Environment

It is well known that straight-teethed shaper cutters present theoretical profile error, which leads to a deviation of the cut gear tooth profile from the involute profile. Taking advantage of the CAD environment, we have visualized and studied shaper cutters at different stages of sharpening. This is advantageous because the effect of any shape or dimension modification of the rake face can be immediately and easily controlled in the design process, thereby saving precious design time. The aim of our research was to create a 3D model in a CAD environment to visualize different sharpening methods and the profile of shaper cutters at different wear stages, and to estimate the inherent profile errors. The aim of using different sharpening methods was to improve the lateral cutting geometry (especially the lateral relief angle) and also to reduce or – at least – keep the profile error within the accepted limits. During the measurements, both the rake angle and the cutter rack profile angle were changed in order to improve the geometry. The edge was generated using numerically computed points and Autodesk Inventor's special commands. Comparative analyses were performed.

Elongation and plasmonic activity of embedded metal nanoparticles following heavy ion irradiation.

Shape modification of embedded nanoparticles by swift heavy ion (SHI) irradiation is an effective way to produce nanostructures with controlled size, shape, and orientation. In this study, randomly oriented gold nanorods embedded in SiO2 are shown to re-orient along the ion beam direction. The degree of orientation depends on the irradiation conditions and the nanorod's initial size. SHI irradiation was also applied to modify spherical metallic nanoparticles embedded in Al2O3. The results showed that they elongate due to the irradiation comparably to those embedded in SiO2. Metallic nanostructures embedded in dielectric matrices can exhibit localized surface plasmon (LSP) modes. The elongated nanoparticles investigated by means of dark-field spectroscopy showed two discrete peaks which correspond to longitudinal and transverse modes.

A Study on the Effects of Cross-sectional Shape Modification on Series-coupled Structures using SEA

A Study on the Effects of Cross-sectional Shape Modification on Series-coupled Structures using SEA

Magnetic Behavior of Virgin and Lithiated NiFe2O4 Nanoparticles

A series of virgin and lithia-doped Ni ferrites was synthesized using egg-white-mediated combustion. Characterization of the investigated ferrites was performed using several techniques, specifically, X-ray Powder Diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and High-resolution transmission electron microscopy (HRTEM). XRD-based structural parameters were determined. A closer look at these characteristics reveals that lithia doping enhanced the nickel ferrite lattice constant (a), unit cell volume (V), stress (ε), microstrain (σ), and dislocation density (δ). It also enhanced the separation between magnetic ions (LA and LB), ionic radii (rA, rB), and bond lengths (A-O and B-O) between tetrahedral (A) and octahedral (B) locations. Furthermore, it enhanced the X-ray density (Dx) and crystallite size (d) of random spinel nickel ferrite displaying opposing patterns of behavior. FTIR-based functional groups of random spinel nickel ferrite were determined. HRTEM-based morphological properties of the synthesized ferrite were investigated. These characteristics of NiFe2O4 particles, such as their size, shape, and crystallinity, demonstrate that these manufactured particles are present at the nanoscale and that lithia doping caused shape modification of the particles. Additionally, the prepared ferrite’s surface area and total pore volume marginally increased after being treated with lithia, depending on the visibility of the grain boundaries. Last, but not least, as the dopant content was increased through a variety of methods, the magnetization of virgin nickel ferrite fell with a corresponding increase in coercivity. Uniaxial anisotropy, rather than cubic anisotropy, and antisite and cation excess defects developed in virgin and lithia-doped nickel ferrites because the squareness ratio (Mr/Ms) was less than 0.5. Small squareness values strongly recommend using the assessed ferrites in high-frequency applications.

Axial Compression Behavior of Wall-like Reinforced Concrete Columns Retrofitted Using Different FRP Schemes

Experimental and numerical investigations on the retrofitting of half-scale wall-like reinforced concrete (RC) columns were conducted. The axial compressive behavior of the control un-strengthened wall-like RC column (having a section aspect ratio of four) was compared with the strengthened columns. The columns were strengthened by employing external confinement through fiber-reinforced polymer (FRP) wraps and/or steel/FRP strips with/without modification of the column cross-section. The characteristics of axial load versus displacement and strain curves were discussed. The experimental results were also compared with the numerical models, which were first validated against the previous studies. A reasonably close agreement was achieved between the numerical and the test results with an error in prediction of less than 10% for the peak load. With the different schemes used for confinement, the enhancement in the load capacity of strengthened columns was in the range of 30–42% of the control column. In addition, significant ductility improvements were seen in schemes that employed the FRP wraps after shape modification.

Toughening static and dynamic damping characteristics of ultra-high performance concrete via interfacial modulation approaches

The damping capacity is one of major concerns for structures under dynamic loads, which significantly affects the safety and service life. Ultra-high performance concrete (UHPC) is a new generation of cementitious material characterized by superior mechanical strength and durability, exhibiting enormous potential in application to innovative structures. However, the weak steel fiber-matrix interface within UHPC leads to insufficient damping performance and poses threats to UHPC structures under extreme dynamic loading conditions. In this paper, various interfacial modulation approaches were investigated to improve static and dynamic damping properties of UHPC, including physical shape and chemical modification of steel fibers, macrofibers and microfibers hybridization. Results show that the interfacial modulation can significantly enhance damping ratio, loss factor and energy dissipation ratio of UHPC, where the chemical modification of steel fibers endows the highest damping ratio. The loss factor and energy dissipation ratio of UHPC reach 0.579 and 0.091 after interfacial modulation, which improved by more than 110% and 100%, respectively. The working mechanisms behind variations of damping performance are attributed to the toughening in interfacial bond and load transfer, leading to improvement in energy dissipating ability of interface. Furthermore, a comprehensive comparison between UHPC and existing vibration damping materials was conducted through multi-criteria analysis from the perspectives of damping performance, mechanical strength, processability and economic benefit, and UHPC with chemical modification of steel fibers exhibits the best overall performance. The findings contribute to inspiring a novel structural vibration control strategy through UHPC with enhanced static and dynamic damping properties for resisting extreme loads.

A novel approach for suppressing leakage flow through turbine blade tip gaps

Tip clearance leakage flow of the turbine bade is an important factor limiting the augment of the high pressure turbine efficiency, which should be suppressed utilizing certain methods. However, the passive control method with the traditional structure is more and more difficult to satisfy the suppressing ability of the advanced turbine demand. In the present paper, a synergetic suppressing method by combining the approach of blade shape modification and spontaneous injection is adopted, to construct a novel tip structure. The aerodynamic characteristics of the tip leakage flow (TLF) with different blade tip configurations, such as the squealer, squealer-winglet (SW) and squealer-winglet-spontaneous injection holes (SWS) composite configurations, are numerically investigated. The impacts of several key geometric parameters, such as the winglet width and the space ng of spontaneous injection holes, are also discussed. Due to the adjustment of the winglet, the SW tip configuration can get better suppressing effect on TLF than the squealer tip. The SWS synergetic suppression tip decrease the leakage flow rate and the leakage mixing loss on the basis of the SW tip due to the blocking effect of the spontaneous injection flow. The key geometric parameters study shows that the suppressing effect of the TLF can be improved by reasonably increasing the winglet width and reducing the spacing between spontaneous injection holes.

Single-objective aerodynamic optimization of a streamlined bridge deck subjected to shape modification using a polynomial emulator and genetic algorithm

Single-objective aerodynamic optimization of a streamlined bridge deck subjected to shape modification using a polynomial emulator and genetic algorithm

Antagonist muscle torque at the ankle interfere with maximal voluntary contraction under isometric and anisometric conditions

While resultant maximal voluntary contraction (MVC) is commonly used to assess muscular performance, the simultaneous activation of antagonist muscles may dramatically underestimate the strength of the agonist muscles. Although quantification of antagonist torque has been performed in isometric conditions, it has yet to be determined in anisometric conditions. The aim of the study was to compare the mechanical impact of antagonist torque between eccentric, isometric and concentric contractions in PF and DF MVCs. The MVCs in dorsiflexion (DF) and plantar-flexion (PF) were measured in isometric, concentric and eccentric conditions (10° s-1) in nine healthy men (26.1 ± 2.7 years; 1.78 ± 0.05 m; 73.4 ± 6.5 kg) through two sessions. Electromyographic (EMG) activities from the soleus, gastrocnemius medialis and lateralis, and tibialis anterior muscles were simultaneously recorded. The EMG biofeedback method was used to quantify antagonist torque. Resultant torque significantly underestimated agonist torque in DF MVC (30–65%) and to a lesser extent in PF MVC (3%). Triceps surae antagonist torque was significantly modified with muscle contraction type, showing higher antagonist torque in isometric (29 Nm) than in eccentric (23 Nm, p < 0.001) and concentric (14 Nm, p < 0.001) conditions and resulting in modification of the DF MVC torque-velocity shape. Estimation of the antagonist torque in isometric or anisometric conditions provides new relevant insights to improve neuromuscular performance assessment and to better design strength training and rehabilitation programs related to the torque applied by agonist and antagonist muscles.

Improvement of the aerodynamic behavior of a sport utility vehicle numerically by using some modifications and aerodynamic devices

The present study proposes aerodynamically optimized exterior designs of a sport utility vehicle using computational fluid dynamics analysis based on steady-state Reynolds-averaged Navier–Stokes turbulence models. To achieve an optimal design, modifications of the outer shape and adding some aerodynamic devices are investigated. This study focuses on modifying this vehicle model’s upper and front parts. At the same time, the rear diffuser and spare tire on the back door as a fairing are used as aerodynamic devices for improving streamlines. All these modifications and add-on devices are simulated individually or in combination to achieve the best exterior design. A variety of Reynolds numbers are used for determining the optimization variables. Tetrahedral cells are used throughout the global domain because of the sharp edges in the geometry of the Discovery car model. At the same time, prism cells around car surfaces are adopted to improve the accuracy of the results. A good agreement between the numerical drag coefficient in the present study for the baseline models and the experimental data has been achieved. Changes in the drag and lift coefficients are calculated for all models. It is clear from the numerical results that the use of combined modifications and add-on devices has a significant effect in improving the overall aerodynamic behavior. As a result, the drag coefficient for the optimal design of the Discovery 4th generation is reduced from 0.4 to 0.352 by about 12% compared to the benchmark. Simultaneously, the lift coefficient is 0.037 for optimal design, and it is an acceptable value. It is found that combining all optimal modified configurations can improve both CD and CL simultaneously.

Slamming impact induced hydrodynamic response in wave-piercing catamaran beam elements with controller

When subjected to a slamming load, wave-piercing catamarans may be vulnerable to damage and deck diving. Aluminum beams are one of the key components of catamaran vessels and improving their stiffness and dynamic smart management is crucial to reducing the impact of waves at sea. The numerical analysis and mathematical modeling of the wave-piercing catamaran beam elements are fresh topics that largely depend on smart control issues. Based on a 2D Wanger type impact force model, this work presents a numerical benchmark study for the hydrodynamic analysis and smart control of wave-piercing catamaran beam elements. The Rankine panel approach also takes into account the impact of the wave-piercing catamaran's forward speed. The wave-piercing catamaran's smart control system consists of a proportional-differential (PD) controller with two piezoelectric layers acting as an actuator and a sensor on the top and bottom surfaces of the beams, respectively. Carbon nanotubes (CNTs) are employed as reinforcement to increase the stiffness of porous beams while assuming their agglomeration effects based on the Mori-Tanaka model. Refined zigzag shear deformation beam theory (RZSDBT) is used to mathematically represent the smart structure, and the related motion equations are generated using the energy technique. The differential quadrature method (DQM) and the Newmark method are used to solve the framework in order to capture the dynamic deflection and flexural moment and describe the Gibbs phenomenon. The effects of the controller, externally applied voltage, CNTs as reinforcement, forward speed, modification of shape and pressure distribution, porosity, deadrise angle, and external loads caused by demi-hulls and the cross-deck are all investigated using numerical studies. These studies look at how these factors affect dynamic deflection, flexural moment and Gibbs phenomenon. Regarding the primary goal of this work, the findings showed that the harmful effects can be greatly controlled with a PD controller. In other words, we can state unequivocally that the controller's assistance reduces the pressure distribution's discontinuity or spike while enhancing the beam's dry area. Additionally, the dynamic deflection and flexural moment are decreased by 49% and 37%, respectively, by employing the controller. The use of CNTs as beam reinforcement, which can reduce dynamic deflection and flexural moment by around 50% and 33%, respectively, is another goal of this work.

Improving the ductility, toughness, and electrical conductivity of poly(lactic acid) by forming poly(lactic acid)/thermoplastic polyester elastomer blend and blend‐based nanocomposites

AbstractIn this study, poly(lactic acid) (PLA)/thermoplastic polyester elastomer (TPEE) (70/30) blend and blend‐based nanocomposites with carbon nanotube (CNT) as a nanofiller were fabricated by conventional melt mixing. Scanning electron microscopy results showed that the blend had a biphasic morphology, and CNTs were selectively distributed in the dispersed TPEE domains in the composites. The presence of CNTs induced the agglomeration and shape modification of TPEE domains, consequently influencing the examined properties. Differential scanning calorimetry results revealed that the crystallizability of PLA was improved after blending with TPEE, and further CNT incorporation increased the crystallization temperature of TPEE during cooling. The elongation at break (EB) and notched impact strength (IS) of PLA were evidently improved in the blend and composites. In particular, the EB and IS in the composites increased by up to 290% and 43%, respectively. The electrical resistivity of neat components and the blend decreased by up to eight orders of magnitude after 3 phr CNT loading due to double percolation in TPEE domains and dispersed CNTs. A percolation threshold at ca. 1 phr CNT loading for electrical conductivity was determined. Rheological property analysis suggested the formation of a pseudo‐network structure, which was attributed to the CNTs increasing the viscosity of the TPEE domains in the composites.

Performance Evaluation of Tillage Knife Discharge Microchannel

Abstract Liquid mineral fertilizers (LMF) have a high sorption ability, can be metered precisely, and the intra-soil application of LMF is relevant. However, the agricultural equipment for this process that introduces the liquid fertilizer under processed soil layer in the form of a wide band has not yet been proposed. The purpose of the study is to evaluate the performance of a 102 mm wide rectangular discharge microchannel of the proposed soil tillage knife designed for deep tillage and intra-soil application of liquid fertilizers and to study the influence of the microchannel length (L) and slot height (h) on the uniformity of discharge. Solidworks Flow Simulation® was used during investigations, and simulation results were compared with experiment results. It has been determined that the effective slot height for water discharge at V i = 3–4 m·s−1 is 0.1 (±0.01) mm, an effective microchannel length is 20 (±2) mm, and the influence of L depends on h. Sheet thickness will not change at a distance of 10–15 mm (b). Fall angle is 0–5°. In conclusion, the proposed discharge microchannel with asymmetrical feed is applicable for intra-soil application of LMF, and the surface tension effect has to be considered. A way to enhancing the sheet uniformity is the geometrical modification of feed channel shape.

Effects of Different Shaped Cavities and Bumps on Flow Structure and Wing Performance

The stall of an aircraft is one of the most dangerous phenomena in the aviation world, resulting in a sudden loss of lift because of boundary layer separation. This work aims to delay separation and to improve wing aerodynamic performances by introducing bumps and cavities on the upper surfaces of the wing. A numerical study on the effects of both cavities and bumps on flow structures and wing aerodynamics of NACA 0012 profile is conducted. The CFX code has been used to perform calculations of steady and uncompressible Reynolds Averaged Naviers-Stokes equations. The airfoil has been exposed to a free stream velocity of 5.616 m/s and chord based Reynolds number of 3.6 x 105 (chord length). A series of test on unmodified airfoil has been carried out for various turbulence models at angles of attack ranging from 0° to 15°. Then, the two-equation k-ω SST (Shear Stress Transport) has been retained for the further cases. Different configurations obtained through a modification of cavities and bumps shape, dimension, and position on the airfoil chord are investigated. Both the shapes considered are semi-spherical and semi-cylindrical, placed at two positions on the airfoil chord. The first location is in suction pick at X/C= 0.3 and the second one is at 0.7. Results show that the application of bumps delays the boundary layer separation and increase drag coefficient. A slight enhancement in lift and drag is observed at angle of attack of 15° for the cases where the cavities are placed at 0.7 m from the leading edge. In addition, calculations show that the stability of the vortex formed inside the cavities depends strongly on their shape and the cylindrical one has better performances.

Small-Molecule 3D Ligand for RNA Recognition: Tuning Selectivity through Scaffold Hopping.

Targeting RNAs with small molecules is considered the next frontier for drug discovery. In this context, the development of compounds capable of binding RNA structural motifs of low complexity with high affinity and selectivity would greatly expand the number of targets of potential therapeutic value. In this study, we demonstrate that tuning the three-dimensional shape of promiscuous nucleic acid binders is a valuable strategy for the design of new selective RNA ligands. Indeed, starting from a known cyanine, the simple replacement of a phenyl ring with a [2.2]paracyclophane moiety led to a new compound able to discriminate between nucleic acids showing different structural characteristics with a marked affinity and selectivity for an octahairpin loop RNA sequence. This shape modification also affected the in cellulo behavior of the cyanine. These results suggest that scaffold hopping is a valuable strategy to improve the selectivity of RNA/small-molecule interactions and highlight the need to explore a new chemical space for the design of selective RNA ligands.