Horizontal Gap Research Articles

Perancangan Mekanisme Pelurusan Kawat SAE 304 (UNS S30400) Galvanized Menggunakan Prinsip Pengerolan

Wire is a complement material on the manufacturing product. Therefore, the wire processes usually bestowed to the middle-low industry. Cutting and straightening wire processes are the most basic process for wire materials. In the middle-small industry, demand of wire materials is 150 kg per day. Seeing this potential, the design of a wire straightening mechanism for middle-low industries is necessary to maximize productivity. The main purpose of wire straightening mechanism design is calculating roll diameters and placement to obtain appropriate rolling force. In designing this wire straightening mechanism, the raw materials are used 3 mm SAE 304 (UNS S30400) Galvanized. The rolling method used in this mechanism is Three-Roll Bending. The empirical method is used on this analysis. Based on the analytical results, roll used on this mechanism are 5 pieces or equal with 3 cycle of rolling process with 40 mm of diameters. The vertical gap between center of rolls is 41.5 mm with 54 mm horizontal gap. Rolling force produced by the analytical roll dimension is 1608.69 N/cycle and that’s enough to give plastic deformation on the 3 mm SAE 304 (UNS S30400) Galvanized wire.

BANDWIDTH AND GAIN ENHANCEMENT OF MICROSTRIP ANTENNA USING DEFECTED GROUND STRUCTURE AND HORIZONTAL PATCH GAP

This research proposed microstrip antenna design using the Defected Ground Structure (DGS) and horizontal patch gap (HPG) for bandwidth and enhancement purposes. This design is to reduce the weakness of a microstrip antenna, which has small gain and narrow bandwidth. The design was simulated in CST Microwave Studio with a working frequency of 2.4 GHz. The design consists of three stages model, i.e., conventional design, DGS modification, and the combination DGS using a Horizontal Patch Gap (DGSHPG). The radius of the conventional circular patch is 16.7 mm. The substrate has 4.6 of dielectric constant, 1.6 of substrate height, and 0.025 of the loss tangent. The simulation results show that the DGS design produces more bandwidth and gain than a conventional design, where the bandwidth and gain improvement are 421.2 MHz and 1.73 dB, respectively. The DGS model is combined with a gap that separates the circular patch (DGSHPG) to achieve the optimum design. The results show the bandwidth and gain improvement of more than 50% and 18.1% compared to the DGS design, respectively. Other parameter performance also shows improvement, such as a reflection factor with -53.3 dB at the center frequency. The physical change also influences the patch’s radius, where it is reduced around 1.4 mm or 8.4% from the original design. Overall, the proposed design has succeeded in achieving bandwidth and gain enhancement and reducing the patch dimension.

Analyses and Optimization of Electrostatic Film Actuators Considering Electrical Breakdown

Electrostatic film actuators are an emerging flexible actuation technique based on the electrostatic field. It is typically composed of two films (the stator and the slider), each of which integrates multiple phase interdigital electrodes. Since the structure and the electrical field distribution are complex, previous researches lack parameter analysis and optimization. Although recent study models and compares the output forces at the same voltage, the actuators of different parameters could survive at different critical voltages. With the concern on the electrical breakdown, this work is a preliminary attempt to analyze the maximum force and critical voltages for different specifications using the method of moments with line-charges. The computation results give qualitative clues about the optimization of various parameters. To achieve a higher maximum force, balancing the breakdown in the vertical gap and the horizontal gap is one of the primary concerns in the design. The theoretical maximum force for electrostatic film actuators can be achieved by different parameter sets: a large insulation layer and electrode space (high critical voltage) or a thin insulation layer and electrode space (low critical voltage). Based on this knowledge, we designed and fabricated an electrostatic film actuator with a force density of 126.5 N/m2, 35% larger than the previous actuators at the same condition.

Rigidity of telescopic boom equipment

As a result of the study, analytical models of the rigidity of the telescopic boom equipment in the vertical and horizontal planes were developed, which take into account: the influence of uneven intersectional vertical and horizontal gaps, the flexibility of the sliding supports, the flexural rigidity of the sections, the rigidity of the telescoping hydraulic cylinder and the lifting hydraulic cylinder. The dynamic coefficient is determined, taking into account the presence of intersectional gaps, with unsteady movement in the vertical and horizontal plane. The influence of intersectional gaps on the coefficient of dynamism and rigidity of the boom equipment taking into account the uneven wear of the sliding supports is established. Keywords telescopic boom, railway crane, stiffness coefficient, dynamic coefficient

The composition of the material phase responsible for the self-healing of macro-cracks in asphalt mortar beams

ABSTRACT Self-healing of asphalt is assumed to be a flow process where bitumen flows into cracks to close them. Hence, the rheological behaviour of bitumen is one of the main factors affecting self-healing together with damage history, healing duration and pressure (external compressive forces or internal thermal expansion). Bitumen-filler interaction influences the flow and it is hypothesised that the material flowing into cracks during self-healing is a mixture of bitumen, filler and eventually fine aggregates. In the paper, the self-healing ratio was determined by mechanical testing and the self-healing was accelerated by an increase of temperature to 100°C. Material draining from asphalt mortar beams into a horizontal gap, representing a crack, was found to be a mixture of bitumen and aggregates with increasing self-healing observed with increasing bitumen and filler content. For the mortar mixture used in this study, a bitumen content of 5.4 wt% was identified to be the limit for self-healing.

Ulama dalam Penguatan Politik Identitas Perspektif Al-Qur’an

‘Ulama are commanding religious figures with far-reaching knowledge; however, currently the term ‘ulama is distorted by unscrupulous people. Frequently, Ulama’s behaviors do not reflect their prestige as Prophet’s heir even though having a number of fanatical adherents. Their fatwa has authoritative influence in establishing post-truth narration. It can cause a horizontal gap and segregation in society if their fatwas are not true. This crisis affected by the increase of identity politics during pre-post political contestation. Meanwhile, the hugest disadvantages are beared by whose tend to believe in their thoughts and behaviors. We analyzed this phenomenon from the perspective of the Qur'an on the meaning of the term ‘ulama and their role in identity politics involvement. We used sociological-normative and descriptive-phenomenological methods to reread some related verses. This study showed, for example, refered to Q.S. Ali ‘Imran (3): 104, ‘ulama are allowed to have an active and positive role in the sphere of politics.

Design, Manufacturing, and Characterization of Integrated Inductors With Two Magnetic Layers

In this article, the simulation results, the technological steps of manufacturing, and the characterization results at low and medium frequencies (20 MHz to a few hundred MHz) of integrated inductors with two magnetic layers are presented. Simulation realized with the high-frequency structure simulator (HFSS) software allows the impact of the vertical and horizontal air gaps on the inductance value for inductors with two magnetic layers to be determined. Inductors with two magnetic layers are manufactured with magnetic thicknesses varying from 100 to 500μm. The interest of this new manufacturing process is compatible with most ferrite. The measurement results show good agreement with the simulation results. By minimizing the vertical air gap, the inductance value increases with a ratio equal to the relative permeability of the magnetic material when field lines are totally canalized into the magnetic layers. The extracted resistance evolution of the inductor on the frequency is explained by taking into account the skin and proximity effects for the conductor losses and the iron losses for the magnetic material.

Higher primary stability of tuberosity fixation in reverse fracture arthroplasty with 135° than with 155° humeral inclination

Proximal humeral fractures in elderly patients are frequently treated with reverse total shoulder arthroplasty, and tuberosity healing improves clinical outcome and patient satisfaction. So far reverse prostheses with different humeral inclination (HI) angles have been used. However, it has not been investigated yet if the HI angle affects the primary stability of the tuberosity fixation in primary reverse total shoulder arthroplasty for proximal humeral fractures in a biomechanical setting. A 4-part fracture was created in 7-paired human cadaver proximal humeri after preceding power analysis. After randomization in a pairwise fashion, reverse prostheses with either 135° (n = 7) or 155° (n = 7) were implanted. The tuberosities were reduced anatomically to the metaphysis of the prostheses and were fixed with 3 suture cerclages in a standardized technique. Tightening was performed with a cerclage tension device with 50 Newton meter (N m). Before biomechanical testing, the initial vertical and horizontal gap formation was measured. The humeri were placed in a custom-made test setup enabling internal and external rotation. Cyclic loading with a gradually increasing load magnitude was applied with a material testing machine starting with 20 N m and increasing by 5 N m after each 100th cycle until failure (>15° rotation of the tuberosities). Any motion of the tuberosities was measured with a 3-dimensional camera system. Overall, the 155° group reached an average of 1460 ± 270 cycles and the 135° group of 1900 ± 271 cycles (P = .048). In contrast to the 135° group, in the 155° group, a mean initial vertical (0.3 ± 0.7 mm) and horizontal (2.7 ± 3.3 mm) gap formation could be observed before cyclic loading. After 1100 cycles, the 155° group showed increased rotation of both lesser and greater tuberosities in all 3 axes around the humeral shaft compared with the 135° group. Primary stability of the reattached tuberosities is significantly increased, whereas rotational movements are decreased in prostheses with an anatomic HI of 135° compared with a 155° HI according to the original Grammont design. In addition, a 135° HI allows an exact anatomic reposition of the tuberosities, whereas this was not possible for the 155° design. However, transferability and clinical relevance of these biomechanical results have to be verified with clinical studies.

Immediate dental implant placement with a horizontal gap more than two millimetres: a randomized clinical trial

The purpose of this study was to evaluate the horizontal dimensional changes in buccal alveolar bone immediately after dental implant placement in the upper premolar area with horizontal gaps >2mm. A total of 48 patients were enrolled in this randomized clinical trial and were randomly assigned to one of three groups. Group I (flap with graft; n=16) patients received an immediate implant with bone graft, membrane, and primary flap closure. Group II (flap without graft; n=16) patients received an immediate implant with primary flap closure only. Group III (flapless without graft; n=16) patients received an immediate implant without graft, membrane, or primary closure. Cone beam computed tomography (CBCT) scans were obtained preoperatively, immediately after implant placement, and at 6 months postoperative to evaluate horizontal dimensional changes in the buccal alveolar bone. Pain intensity was measured using a numerical rating scale. CBCT examinations revealed that bone had filled the horizontal gap in all three groups. Group II showed the greatest horizontal dimensional changes in the buccal alveolar bone, followed by group I. The least amount of change was recorded for group III. Furthermore, significantly less postoperative pain was recorded in group III when compared to the other groups. Short-term results suggest that the ‘flapless without graft’ technique shows similar results to the ‘flap with graft technique’ for immediate implant placement in the maxillary premolar extraction site with a horizontal gap >2mm, when the bone plate is intact.

High-efficiency cross-polarization conversion metamaterial using spiral split-ring resonators

We report on a high-efficiency cross-polarization conversion metamaterial design consisting of novel spiral split-ring resonators (SRRs). Numerical simulations on the resonant electric field and surface current distributions demonstrate that the cross-polarization response is attributed to the charge accumulation in the horizontal SRR gap. The dependencies of resonance frequency on the structural parameters of the SRR reveal that an inductive-capacitive resonance dominates the SRR. We further show that the polarization conversion efficiency can be significantly enhanced by integrating two orthogonal gratings, which enable a linear polarization wave to be rotated to its orthogonal direction with a high efficiency of ∼90%. These results offer a way to engineer novel high-performance metamaterial polarization devices.

DYNAMICS INTERACTION OF THE SHARE MOLE PLOW WITH SOIL IN THE FORMATION OF THE CAVITY FORIMPERVIOUS SCREEN

To maintain moisture and best spread it in the horizontal direction under in-soil irrigation of agricultural plants there is a necessity of laying moisturizers together with an impermeable screen. For this purpose, share mole plow can be used. Substantiation of tool's geometrical parameters and modes of operation is an actual scientific problem. Solution of this problem requires formalizing the soil as the medium on which the tool is directed, as well as formalizing the interaction of the tool with the soil. This article discusses the dynamics of the ploughshare forming a horizontal gap into which the anti-filter screen extends. For this, the interaction of the plowshare of the mole with the soil in the contact zone during compaction of the walls of the formed cavity is under considered. Herewith, the degree of compaction of the walls affects the stability of the arch of the formed cavity. During the study, the soil is presented in the form of an elastic viscous deformable medium, and the ploughshare - in the form of an absolutely solid. The surface of this solid is described by a three-dimensional equation in an implicit form, the coefficients of which characterize the geometric parameters of the tool. In a previous article, the authors obtained functions of the rates of soil deformations from the action of the tool. Based on the strains functions with use the physical equations of the connection between stress and strains, the functions of the stress components on the mechanical properties of the soil and the parameters of the tool are obtained. The stress components obtained in the contact zone of the plowshare with the soil made it possible to determine the function of changing the specific volume of the soil. This function is inversely proportional to soil density. The use of equilibrium equations on the contact surface made it possible to determine the components of the forces that act from the soil side on the ploughshare. Integration of the obtained components of the distributed forces over the ploughshare surfaces made it possible to obtain the sum of the resistance forces to the ploughshare movement, depending on the mechanical properties of the soil and tool parameters. As a result of the study, rational parameters of the equation coefficients of the ploughshare surface that characterize its geometric parameters are determined.

Applying the adjoint-free 4dVar assimilation to modeling the Kuroshio south of Japan

Operational ocean nowcast/forecast systems require real-time sampling of oceanic data for representing realistic oceanic conditions. Satellite altimetry plays a key role in detecting mesoscale variability of the ocean currents. The 10-day sampling period and horizontal gaps between the altimetry tracks of 100 km cause difficulties in capturing shorter-term/smaller-scale ocean current variations. Operational systems based on a three-dimensional variational method (3dVar) do not take into account temporal variability of the data within data assimilation time windows. Four-dimensional data assimilation technique is considered as a possible tool for more efficient utilization of the observations arriving from satellite altimeters by the dynamically constrained interpolation. In this study, we develop and test the performance of the adjoint-free four-dimensional variational method (a4dVar) for operational use in regional models. Numerical experiments targeting the Kuroshio path variations south of Japan demonstrate that the a4dVar scheme dynamically corrects the initial condition so as to effectively reduce the satellite altimetry data misfit during a 9-day time window. The corrected initial condition further contributes to improvements in the skill of reconstruction of the Kuroshio path variation in a 30-day lead hindcast run.

Time- and strain-dependent nanoscale structural degradation in phase change epitaxial strontium ferrite films

Topotactic phase transition between metallic, perovskite SrFeO3 and insulating, Brownmillerite SrFeO2.5 has been extensively studied due to the potential applications in resistive switching devices for neuromorphic computing. However, its practical utilization as memristors has been hindered by the structural instability of SrFeO3, which is often ascribed to the generation of oxygen vacancies to form SrFeO3-δ. Here we reveal that the dominating defects generated in SrFeO3 epitaxial thin films are atomic scale gaps generated as a result of interfacial strain. Our correlated time- and strain-dependent measurements show that tensile strained SrFeO3 films form vertical, nanoscale gaps that are SrO-rich, which are accountable for the observed metal-to-insulator transition over time. On the other hand, compressively strained or small lattice mismatched SrFeO3 films mainly yield horizontal gaps with a smaller impact on the in-plane transport. The atomic scale origin of such defects and their impact on device performance need to be further understood in order to integrate phase change materials in oxide electronics.

Addressing Horizontal and Vertical Gaps in Educational Systems

Students are often ill-prepared for the leap in expectations within disciplines when they make the transition from secondary to university-level instruction. Moreover, another equally large challenge exacerbates these vertical disciplinary gaps. At all levels, instruction takes place largely in disciplinary silos – in language and literature, history, mathematics, science, and so on. Learning goals in these silos are often phrased in very different language, e.g. ‘becoming a reader’ (or writer) in language arts, ‘inquiry’ in science, and ‘problem solving’ in mathematics. Such horizontal gaps result in instruction being far less coherent from the student’s perspective than it might be. The Teaching for Robust Understanding framework, known as TRU, may provide a means of addressing both kinds of gap. TRU focuses on the nature of learning environments that support the development of students as powerful learners. Through the lens of the TRU framework one can see commonalities across disciplines and across grade levels, and shape instructional practices accordingly. Within any particular discipline, treating students as active sense makers and arranging learning environments to provide opportunities for active sense making may help to bridge the gap between secondary and higher education.

Electric field emission characteristics of a triode-structured metallic edge emitter from geometric conditions

Spindt-tip type cold electron emission has potential in various applications; however, it has a limited current capacity that prevents the emitters from being used for higher current sources, and the fabrication of the emitters is not easy. In this study, we investigate the electric field emission characteristics of a triode-structured metallic edge emitter from geometric conditions. We perform a systematic simulation based on Fowler-Nordheim theory to analyze the feasibility of using the proposed emitter. The dependences of the emission current, electron transmittance, and region of the triode mode on specific geometrical parameters, including the anode-gate vertical distance, gate-cathode vertical distance, gate-cathode horizontal distance, anode voltage, and gate voltage, are analyzed. The results show that the electric field for a narrow gate-cathode vertical distance is superior to the electric field of the gate electrode for a narrow gate-cathode horizontal distance, while the electric field for a wide gate-cathode vertical gap is more dominant than the electric field of the anode electrode for a wide gate-cathode horizontal gap. Moreover, the electron transmittance gradually increases with a low gate voltage, wide anode-gate vertical distance, and high anode voltage, and the region of the triode mode also increases with a high gate voltage, wide anode-gate vertical distance, and low anode voltage. Consequently, our results appear to be effective for an optimization in an experiment and are expected to improve present electric field emission techniques.

A modified leaky multi-trench fiber with managing chromatic dispersion

A new scheme of modified multi-trench fiber (MTF) with chromatic dispersion management is proposed. In this structure, the low refractive-index trenches are broken along the x and y axes by four gaps. The rod-arrays, composed of high Ge-doped rods, are arranged symmetrically in the horizontal gaps. The numerical investigations indicate that the mode area of 1051μm2 can be achieved in effective single-mode (SM) operation at 1.064μm wavelength. The high-order modes (HOMs) are well suppressed. Moreover, through optimizing the key parameters of rod-arrays, the zero chromatic dispersion is controllable and can be maintained at 1.064μm wavelength. We hope that the modified MTF can be further applied to high power fiber lasers and amplifiers.

Influence of the shape of the inner boundary on thermomagnetic convection in the annulus between horizontal cylinders: Heat transfer enhancement

The paper studies convection in a horizontal annular gap filled with a magnetic fluid or gaseous oxygen under the influence of gravitational and magnetic forces. A current-carrying conductor and an external uniform magnetic field magnetizing an internal cylinder of a material with high magnetic permeability were considered as a source of a magnetic field. The influence of the shape of the inner cylinder and the magnitude of the magnetic field gradient on the heat transfer was studied. It is found that the strength of the magnetic field created by a current-carrying conductor is insufficient to compete with gravitational convection. In the absence of gravity, a variety of convective structures and the hysteretic nature of the transition between them were discovered. The shape of the conductor is an additional factor affected the convection.The effect of a high gradient magnetic field of a magnetizing inner cylinder on convection is studied too. In the case of magnetic fluid, this can ensure the excess of magnetic forces over gravitational by hundreds of times. Heat transfer in an external field with strength of 150 kA/m from a circular magnetized cylinder can be increased 3–4 times, and in a field of 1000 kA/m 4–6 times compared with natural gravitational convection. Heat transfer can be further enhanced by 40–50% by choosing the shape of the inner cylinder.The magnetic field can increase heat transfer through an annular gap filled with gaseous oxygen, 2 times.

Improved Magnetic Circuit Model for Magnetic Shielding Effectiveness in Rogowski Coil

The magnetic circuit approach is commonly used as a powerful analysis and design tool for magnetic devices because of its computational simplicity and comparable accuracy. Currently, magnetic circuit solutions for magnetic shielding effectiveness assume a rectangular shell structure of shielding under vertical external magnetic fields, leading to inaccuracies in parametric analysis. In this article, an improved magnetic circuit model is proposed by considering the hollow cylindrical structure of shielding to investigate magnetic shielding effectiveness in Rogowski coils. The proposed model is verified by simulation studies based on the finite-element method (FEM) for a wide range of design parameters. It is shown that magnetic shielding effectiveness of magnetic circuit models has no more than 27% error for horizontal air gaps and 17% for vertical air gaps when the shielding thicknesses and the shielding distances from non-magnetic former are varied from 5 to 30 mm. The proposed magnetic circuit approach has also been confirmed by magnetic shielding of a hollow toroidal structure. It is found that the maximum percentage error in the magnetic shielding effectiveness does not exceed 18% for the same parameter range. The method is also validated for the changes in air gaps, permeability of shielding materials, and the major radius of the non-magnetic former.

Adaptation accuracy of milled lithium disilicate crowns: A 2D and 3D microCT analysis.

Evaluate the effects of the scanning techniques and the crystallization in the internal and marginal adaptation of milled lithium disilicate crowns by two techniques computer microtomography analysis. Sixteen polyurethane teeth prepared for a complete crown were divided into two groups according to the scanner method (n = 8): indirect (IND), dental stone models were scanned with laser-surface scanner, and direct (DIR), digital typodont creates with an intraoral scanner. Internal and marginal gap were evaluated by micro-computed tomography (microCT). The replica technique (RT) was applied for analysis of total volume (TV) and marginal volume (MV) gap in microCT. The data showed normal distribution (Shapiro-Wilk test). One-way ANOVA (scanner techniques) with repeated measures (crystallization) was performed. Multiple comparisons were performed with Bonferroni adjustment (α = .05). The axial gap showed a significant difference between the times (P = .017) for lower values after crystallization. The vertical marginal gap presented a significant difference in times for higher value after crystallization (P = .001). The marginal horizontal gap IND was greater than DIR after crystallization (P = .001) and IND before lower than after crystallization. For TV was not significant difference and MV in DIR was reduction (P = .002) after crystallization. Crystallization changes the relationship between the crown and tooth, reducing internal gap and preventing the adequate fit in indirect and direct scanning. The measure gap under technological methodology is useful for adjust clinical parameters prosthetic in the CAD/CAM and the applicability of the new possibilities of analysis.

Modal characteristics and the tunability of horizontal hybrid gap plasmonic waveguide

We propose and numerically investigate the modal characteristics of tunable horizontal hybrid gap plasmonic (HGP) waveguides at the optical communication wavelength of 1.55 μm. The HGP waveguides consist of a metal wedge coupled with a dielectric waveguide via an air gap in the horizontal direction. We obtain a long propagation length (at centimeter scale) in these HPG waveguides while maintaining the propagation mode size at a deep-subwavelength scale (λ2/104). The tunable mechanisms for the HGP waveguides are analyzed in detail. We also propose a liquid-based tunable HGP waveguide and analyze the tunable characteristics of this device in detail. The simulation results indicate that the proposed tunable HGP waveguides have a high potential for applications in reconfigurable plasmonic devices and lab-on-a-chip systems.