Zig Zag Research Articles

Strain-controlled Rashba spin-orbit coupling effect in SnS and SnSe monolayers

The miniaturization of transistors and the high density of integrated circuits makes conventional transistors reach a size limit, causing leakage currents, unstable performance, and increasing production cost. Spin field effect transistors (SFETs) based on spintronics use electron spin as an information carrier and regulate electron spin degree of freedom for storing and processing information. As a class of spintronics, Rashba spin–orbit coupling (SOC) effect attracts increasing attention because of its electric tunability. SFETs based on Rashba SOC and two-dimensional materials will make a qualitative leap in future semiconductor devices. Based on first-principles calculations, it is found that the applied strains along zigzag (ZZ), armchair (AC), and biaxial direction make the bandgaps of SnS and SnSe monolayers (ML) have an indirect-direct-zero transition. SnS and SnSe ML have a more stable electron spin and stronger Rashba spin splitting than InGaAs/InAlAs heterojunction and Au(111) surface. For SnS ML, 6% tensile strain along ZZ direction not only stabilizes the electron spin but also strengthens Rashba spin splitting to a maximum of 0.76 eV Å. For SnSe ML, 2% tensile strain along biaxial direction makes Rashba spin splitting strength reach a maximum of 1.33 eV Å.

Pengaruh Kecepatan Fluida Dan Jarakantar Zig Zag Filter Foam Filler Terhadap Efektifitas Cooling Tower

The purpose of this study was to determine the effect of fluid velocity and the distance between zig zagfilters on the cooling tower by varying the distance between zig zag foam bio filters. In this study using bio filterfoam material in the form of zig zg by using wire mesh where the tested distance is 5cm, 10cm, and also 15cm. Thenthe water is heated using a heater until it reaches a temperature of 40ºC and then the water is flowed up with a pipeusing a pump and released using a nozzle, then the hot water will go down to the reservoir by passing the bio filterfoam filter that has been installed with a distance of 5cm , 10cm and 15cm. Where there is also a disposal valve thatis done that is closed and faucets are also open ½ and fully open. Good cooling value is indicated by good results oncooling or also cooling faster which is 5cm which results in an average cooling value of 36.53 ºC when the exhaustvalve is fully open, while the value is not good or less optimal cooling it is shown when the drain valve is closed at azig zag distance of 10cm and also 15cm which yields 37.60 ºC data at a zig zag distance of 15cm.

Polarization independent and non-reciprocal absorption in multi-layer anisotropic black phosphorus metamaterials.

The polarization independent and non-reciprocal absorption is particularly crucial for the realization of non-reciprocal absorption devices. Herein, we proposed and studied the absorption response of two- and three-layer anisotropic black phosphorus (BP) metamaterials by using the finite-difference time-domain (FDTD) simulation and radiation oscillator theory (ROT) analysis. It is shown that, due to unequal surface plasmon resonant modes excited in zigzag (ZZ) and armchair (AC) directions of the anisotropic BP layer, tunable polarization independent and dependent absorption can be achieved for the proposed multi-layer anisotropic BP metamaterials with AC-AC, AC-ZZ, ZZ-AC, AC-AC-φ, AC-ZZ-φ, and ZZ-AC-φ configurations. Especially, the polarization independent absorption also can be realized for odd-layer BP nanostructures. Unlike previous reports, polarization independence only can be achieved in the even-layer BP nanostructure. Moreover, tunable non-reciprocal absorption with the extremely large non-reciprocal degree (NRD) is also found in the case of AC-ZZ and ZZ-AC configurations and AC-ZZ-φ and ZZ-AC-φ configurations. These results may open up the possibility of realizing tunable polarization independent and non-reciprocal plasmonic devices based on 2D materials.

Design and analysis of microstrip antenna with zig-zag feeder for wireless communication applications

This paper is presented a microstrip antenna with a zig-zag feeder for wireless communication, it has a wideband frequency spectrum (2-14) GHz. The proposed antenna is designed with a zig zag feed line which gave a wideband frequency and acceptable gain (7.448-5.928) dB, this antenna has zig zag slots printed in the ground plane on a lower side of the dielectric substrate, a certain form tuning stub is used to increase the matching between the feeder in the top layer of the substrate and ground plane in the bottom, this stub has an elliptical slot to performance matching input impedance with the feed line. The feeding technique used to feed this antenna is a strip feed line of 50 Ω. Different types of techniques are used to enhance the bandwidth of this antenna to get a wideband suitable for the requirements of the UWB antenna such as adjust the feed point position of the feed line with a tuning stub. All the radiation properties of the presented antenna are tested such as bandwidth, radiation pattern, and, gain.

Density functional theory study of the mechanical behavior of silicene and development of a Tersoff interatomic potential model tailored for elastic behavior

Silicene, a graphene-like 2D material made from Si atoms, has been fabricated and studied for its promising applications in micro/nanoelectronics. For the reliable function of silicene devices, it is important to investigate silicene’s mechanical properties. In this study, the authors conducted density functional theory (DFT) simulations of mechanical tests of silicene and investigated the elastic modulus and mechanical response such as structural transformation. In addition, the authors optimized the Tersoff potential parameters using a gradient-based minimization with a grid search method in hyperdimensional parameter space, to match the DFT calculation results in the elastic regime. With the new parameter set, the elastic moduli of silicene in the zigzag (ZZ) and armchair (AC) directions were computed with molecular statics (MS) simulations and compared with those of other Si interatomic potential models and DFT results. In addition, uniaxial tensile tests along the ZZ and AC directions were performed to examine how far the Tersoff model is transferable with our new parameter set to describe the nonlinear mechanical behavior of silicene. The results of uniaxial tensile tests suggest that the angle penalty function in the Tersoff model needs to be modified and that the stress–strain curve predicted with this modification shows improvement compared to the original function.

Reconstructed edges of T phase transition metal dichalcogenides

As surfaces are to bulk materials, edge configurations greatly influence the properties and ensuing applications of two-dimensional (2D) materials. Being a large family of “beyond graphene”, 2D transition metal dichalcogenides (TMDCs) have many potential applications due to diverse phases and tunable properties. Unlike the well-studied H phase TMDCs initiated by MoS2, the edge structures of T phase TMDCs remain poorly studied. Herein, taking freestanding T phase PtSe2 as a prototype, we rationally construct 43 edge structures on the basis of conventional zigzag (ZZ) and armchair (AC) edges, and systematically evaluate their thermodynamic stabilities and relevant properties using density functional theory. Twelve most stable reconstructed edges (five ZZ-oriented and seven AC-oriented) are found to be highly stable at different experimental conditions, which can be achieved by precise control of synthesis conditions. Further Wulff constructions suggest hexagonal shapes with ZZ edges would be the equilibrium structures of the freestanding T phase PtSe2 clusters or quantum dots. Electronic structure calculations show tunable band gap via edge reconstruction. Some reconstructed edges also exhibit excellent catalytic activity for hydrogen evolution reaction. Our work is expected to advance the knowledge of edge structures of T-phase TMDCs, and motivates materials design via TMDC edge engineering.

The Mechanism of Graphene Vapor-Solid Growth on Insulating Substrates.

Wafer-scale single-crystal graphene film directly grown on insulating substrates via the chemical vapor deposition (CVD) method is desired for building high-performance graphene-based devices. In comparison with the well-studied mechanism of graphene growth on transition metal substrates, the lack of understanding on the mechanism of graphene growth on insulating surfaces greatly hinders the progress. Here, by using first-principles calculation, we systematically explored the absorption of various carbon species CHx (x = 0, 1, 2, 3, 4) on three typical insulating substrates [h-BN, sapphire, and quartz] and reveal that graphene growth on an insulating surface is dominated by the reaction of active carbon species with the hydrogen-passivated graphene edges and thus is less sensitive to the type of the substrate. The dominating gas phase precursor, CH3, plays two key roles in graphene CVD growth on an insulating substrate: (i) to feed the graphene growth and (ii) to remove excessive hydrogen atoms from the edge of graphene. The threshold reaction barriers for the growth of graphene armchair (AC) and zigzag (ZZ) edges were calculated as 3.00 and 1.94 eV, respectively; thus the ZZ edge grows faster than the AC one. Our theory successfully explained why the circumference of a graphene island grown on insulating substrates is generally dominated by AC edges, which is a long-standing puzzle of graphene growth. In addition, the very slow graphene growth rate on an insulating substrate is calculated and agrees well with existing experimental observations. The comprehensive insights on the graphene growth on insulating surfaces at the atomic scale provide guidance on the experimental design for high-quality graphene growth on insulating substrates.

Control of the Transformer Phase Powers Using a Single-Phase Voltage Source

Power flow in three-phase distribution grids containing single-phase prosumer voltage sources strongly depends on the RMS value of the voltage of these sources and their phase shifts in relation to the grid voltage. The ideal way to control single-phase prosumer sources should guarantee no return active power to the MV grid through a distribution transformer and no additional reactive power flows in the LV grid. This means that the active power of the one-phase voltage source is consumed by other single-phase customers (in the same phase or in other phases) and the reactive power of this source is equal to zero. The paper presents the results of the investigations of the dynamic control system of a single-phase voltage source that allows meeting these conditions. On the basis of steady-state calculations, the static characteristics of the above-mentioned control, needed to determine of the proper working point of a prosumer source were also obtained. The control process involves the control of the RMS value and phase angle of the voltage source against the phase voltage of the LV grid, to which the source is connected, with simultaneous control of the current phase angle issued by the power source against voltage. The result of the research is the confirmation of the necessity of using a zig–zag connection of the secondary side of distribution transformers. The developed control system of the prosumer voltage source does not fully control the active power of individual phases of the distribution transformer. The paper shows that the power losses in a distribution transformer strongly depend not only on the active power of the prosumer source, but also on its effective voltage and phase in relation to the transformer voltage.

MANEUVERING PERFORMANCE OF TUGBOAT USING COMPUTATIONAL FLUID DYNAMICS (CFD) APPROACH

Concerning on navigational safety of a ship, comprehensive investigation of manoeuvrability of the ship is prominently required. The turning instability due to improper speed and magnitude of the rudder angle is vulnerable to serious accidents such as collision especially in the confined waters. This paper presents a computational fluid dynamic analyses on manoeuvrability performance of a tug in calm water. Here, the characteristics of the turning ability and zig-zag characteristics of the tug has been assessed due to effect of the various angles of twin-rudder and turning speeds. The results revealed that the increase of rudder’s angle resulted in subsequent reduction of her advance diameter from 144 m, 108 m, 96 m to 92 m. While for zig zag manoeuvre, the first overshoot angle is 0.6° and 1.08° for 10°/10° and 20°/20° rudder’s angle respectively. The first overshoot and second overshoot angle are within the IMO criteria which is below 20° and 25°. However, the increase of turning speed from 7 knots to 9 knots has been proportional with the increase of the turning diameter (advance diameter) from 70 m to 105.2 m. Basically, the turning performances of the tug manoeuvring with the turning speed of 7 to 9 knots incorporated with rudder’s angle 20°, 25°, 30° and 35° have been complied with IMO manoeuvring standards. This preliminary analysis contributes very valuable findings at early ship design stage to provide a safety of the navigational guidance for turning ability of the tug.

Dynamically tunable narrowband anisotropic total absorption in monolayer black phosphorus based on critical coupling

A dynamically tunable anisotropic narrowband absorber based on monolayer black phosphorous (BP) is proposed in the terahertz (THz) band. The proposed absorber consists of a monolayer BP and a silicon (Si) grating, which is placed on a silica (SiO2) isolation layer and a gold (Au) substrate. The benefit from the critical coupling mechanism with guided resonance is the efficiency of the absorption can reach 99.9% in the armchair (AC) direction and the natural anisotropy of BP makes it only 87.2% in the zigzag (ZZ) direction. Numerical and theoretical studies show that the absorption efficiency of the structure is operatively controlled by critical coupling conditions, including the geometric parameters of the Si grating, the electron doping of BP and the angle of incident light, etc. More importantly, in the absence of plasmon response, this structure greatly enhances the interaction between light and matter in monolayer BP. In particular, there are several advantages in this structure, such as extremely high-efficiency absorption, excellent tunability, outstanding intrinsic anisotropy and easy manufacturing, which will show unusual and promising potential applications in the design of BP-based tunable high-performance devices.

Fracture behavior dependent on crack-tip shapes in nanoscale crack-defect monolayer boron nitride sheets

ABSTRACT Nanoscale defects, including cracks, circular holes, and the triangular-shaped defects, often occur in the growth of boron nitride nanosheets (BNNS). In this study, the fracture behavior of chiral BNNS with different crack-tip shapes and the interactions of nanoscale crack-defects are studied using molecular dynamics (MD) simulations and finite element (FE) analysis. Both MD and FE results indicate that the fracture strength of BNNS with two crack tips (t = 2) is significantly higher than that with one crack tip (t = 1), in which the difference in zigzag (ZZ) direction is more obvious than that in armchair (AC) direction, mainly due to the fact that the change of bond angles near the crack tips is more substantial in the ZZ direction than those in the AC direction. Our results show that the fracture strength of BNNS strongly depends on crack-tip shapes, chiral angles, the defect-to-crack tip spacing and deflection angles. Checking against the current MD simulations and FE analysis shows the present results are reasonable. This study should be of great importance for enhancing the fracture performance of BNNS by modulating their crack-tip shapes and the interactions of nanoscale crack-defects.

A novel graphene pressure sensor with zig–zag shaped piezoresistors for maximum strain coverage for enhancing the sensitivity of the pressure sensor

The demand for flexible and wearable sensors is increasing day by day due to varied applications in the biomedical field. Especially highly sensitive sensors are required for the detection of the low signal from the body. It is important to develop a pressure sensor that can convert the maximum input signal into the electrical output. In this paper, the design and performance of graphene piezoresistive pressure sensors have been investigated by zig–zag piezoresistors on the square diaphragm. On the applied pressure, deformation is sensed by the piezoresistors above the diaphragm. Finite element analysis is carried out to investigate the effect of zig–zag piezoresistors on the square diaphragm. Simulated results for the optimized design are obtained for an operating range of 0–100 psi for pressure sensitivity.

Catalyst particle size dependent carbon nanotube cloning

The single walled carbon nanotube (SWCNT) cloning or its seeded growth with a catalyst particle docked on one of its ends was proposed as the ultimate solution for chirality-specific SWCNT synthesis and, therefore, revealing the effect of catalyst particle size on the robustness of the SWCNT cloning is crucial for experimental designs. Through systematic atomic simulations, we have clearly demonstrated that the robustness of SWCNT cloning depends on both the chiral angle of the SWCNT and the ratio of the diameters between the SWCNT and the docked catalyst particle. The zigzag (ZZ) or near ZZ SWCNTs are highly sensitive to the size of the docked catalyst particle. A small change of the catalyst particle size could lead to a variation of the SWCNT’s chirality. In contrast, armchair (AC) or near-AC SWCNTs are less sensitive to the size of the docked catalyst particle and able to maintain their original chiralities within ∼30% variation of the catalyst particle size. This study greatly deepens our understanding of SWCNT’s growth mechanism and provides a quantitative guidance for SWCNT cloning.

ZigZagZ: Improving mechanical performance in extrusion additive manufacturing by nonplanar toolpaths

This study investigates the effect of novel non-planar deposition methods in fused filament fabrication (FFF) additive manufacturing. A range of non-planar geometries were developed including a ZigZagZ sequence in which filaments were deposited as the nozzle moved in the X or Y direction while simultaneously zigzagging up-and-down i.e. in the Z direction. As a result, repeating non-planar layers were generated throughout the specimen’s geometry. The use of the ZigZagZ toolpath to deposit the material significantly improved the mechanical performance of parts manufactured by FFF in the Z-direction by up to 62% in strength, 123% in strain-at-fracture and 245% in toughness compared to an optimised conventional planar geometry. All specimens in the study had only a single filament through their thickness; they were specially developed to enable precise mechanical characterisation. This is the first work to have developed and analysed nonplanar deposition with cyclic nonplanar nozzle movement of a geometric length scale similar to the nozzle diameter. Three novel toolpath designs were developed for this study: (i) zigzag (ZZ), based on the aforementioned ZigZagZ deposition; (ii) up-down (UD) involving vertically deposited nonplanar bulges with interconnecting planar sections; (iii) forward-back (FB) employing the nozzle’s movement forward and backward during planar deposition to enhance the nozzle’s contact and promote the ploughing of the deposited filament. These designs - along with the conventional planar toolpath designs (original (OR)) - were characterised and their mechanical properties compared to generate new understanding about the impact of deposition with the Z coordinate varying along the path on performance. The geometrical outcomes of these different deposition strategies were analysed microscopically to assess the effects of nonplanar toolpaths on the filament-scale geometry. It was established that the ZZ strategies resulted in higher extruded-filament thickness compared to OR. Additionally, various ZZ designs were developed to understand the impact of the zigzag height-to-width ratio and size not only on mechanical properties, but also geometry and fracture path. Fractographic analysis indicated that nonplanar FFF extrusion promoted through-filament fracture, suggesting a reduced concentration of stresses at interlayer bonds by redirecting the load into the filament; this could contribute to the increased level of toughness observed in ZZ specimens. The understanding developed in this study is readily adaptable for the use in both single-wall and infill geometries to provide their improved mechanical performance. A broad range of potential industrial applications and research relevance resulting from the findings is discussed in addition to future development opportunities. • Zigzag interfaces improved load-bearing capacity, strain-at-fracture and toughness. • Interfacial weakness is caused by filament-scale geometry, not the bond. • Nonplanar geometry overcame geometric vulnerabilities of the interface in FFF. • Zigzag nonplanar unit can be used for both thin-walled and infilled structures. • Zigzag geometry redirected the load into the filament, increasing plasticity.

“CONSTANT, ZIG-ZAG LINEAR, OR MULTIPLE?”: THEMATIC PROGRESSION PATTERNS ON EFL STUDENTS’ RECOUNT TEXTS

The main problem faced by EFL students in writing English texts includes the difficulties to produce a cohesive and coherent text that it seems necessary to show how the tools of Theme and Rheme can be used to help construct the students' good English writing. This study aimed to find out the types of thematic progression patterns in each clause of the recount texts written by students and the dominant pattern of thematic progression revealed from the texts. The research design of this study is a qualitative method which employed the study instrument of the students' recount texts at class IX of SMAN 2 Langsa, Aceh. A content analysis approach by using a Theme and Rheme framework generated from a theory of Systemic Functional Linguistics (SFL) was used to analyze the thematic progression patterns on the students' recount texts, which included several steps: reading the student's texts, identifying the theme and rheme of every clause of the student's text, describing the thematic progression patterns of student's text and drawing the thematic progression pattern on student's text. The findings of the analysis indicated that there are three (3) thematic progression patterns found on the students' recount texts: the Theme Constant, the Theme Zig Zag Linear pattern and Theme Multiple patterns. The dominant type of thematic progression patterns constructed by the students into their recount texts was revealed mostly on 123 constant or reiteration patterns (76.8%), followed by zig-zag patterns of 35 times (21.8%) and 9 times (1.25%) of multiple patterns. The results of this study will be facilitative as the tools for English language teaching and learning classrooms particularly for writing English texts.

Pengaruh Tipe Infill dan Temperatur Nozzle terhadap Kekuatan Tarik Produk 3D Printing Filamen Pla+ Esun

The increasing technology of the manufacturing industry now makes the industry competition, especially in the field of manufacturing increasingly stringent in developing products with accurate dimensions. The process of getting accurate and precise dimension results is very important in improving the quality of a product to be made. With the development of this technology, the manufacturing industry has begun to develop products with the method of adding materials known as rapid prototyping or layer manufacturing, one of which is technology using 3D printing machines. This research was carried out on a PRUSA 3D Printing FDM model with dimensions of 220 mm x 220 mm x 250 mm and using a nozzle measuring 0.4 mm. The material used is a PLA + filament with a diameter of 1.75 mm with variations in the nozzle temperature parameters (205 ° C, 215 ° C, 225 ° C), layer thickness 0.2, bed temperature 60 ° C, travel speed 100, printing speed 50 , infill type (Grid, Lines, Triangles, Tri Hexagon, Cubic, Cubic Subdivision, Octet, Quarter Qubic, Concentric, Zig Zag, Cross, Cross 3D, Gyroid) which will be determined in Ultimaker Cura 4.4.0 software, resulting in 39 printed sample. The results obtained after testing the highest tensile strength values are found in the 22nd test specimen that is 43.20 MPa with 215 nozzle temperature parameters and Infill Type Concentric, while the lowest tensile strength values are found in the 22nd test specimen which is 24.50 MPa with nozzle temperature parameters 205 ° C and Infill Type Cross.

Finite Element Analysis of Carbon Nanotube Structured Badminton Racket

The deflection sensitivity of badminton racket and specific design parameters need to be considered while developing a rugged racket structure. Titanium alloys, ceramics, fibreglass and carbon fibers are using to develop badminton rackets. During swing and hit the racket for smashes, the structural failures are challenging. This paper focused on material selection to withstand to the max load applied. Armchair and Zig–Zag Carbon Nano Tubes are studied using Finite Element Modelling (FEM). The Stress–Strain curve, modulus of Elasticity, Bending Stiffness and Moment of Inertia are analysed with varying radius of the carbon nanotube. Max bend is 900 along with twist angle 500 is applied on SWCNT Structures. The harvested results are impressive with reasonably good elastic and applied loads withstand properties to elect the Zig–Zag SWCNT structures for developing the badminton rackets.

Mechanically Tunable Near-Field Radiative Heat Transfer between Monolayer Black Phosphorus Sheets.

As a cutting-edge two-dimensional (2D) material, black phosphorous (BP) has been demonstrating a promising performance in the field of near-field radiative heat transfer (NFRHT) due to the excitation ability of its surface plasmon polaritons. Here, we have systematically demonstrated the effect of mechanical strain on the NFRHT between two separate BP sheets. First-principles calculations predict that a certain amount of mechanical strain (4% along biaxial or 6% along zigzag (ZZ)) can trigger an orthogonal switch of anisotropic optical conductivity by regulating the effective mass of electrons. The mismatched coupling of surface plasmon polaritons between the pristine and strained BP results in a 73% change in NFRHT. The studied mechanically tunable NFRHT unfolds a new degree of freedom for controlling the near-field heat transfer and sheds light on an invaluable approach to designing two-dimensional material-based thermal and electrical applications.

Effect of infill pattern on mechanical properties of 3D printed PLA and cPLA

PLA are the most sustainable alternatives and can fit in a wide-range of applications of electronics, nonwoven fabrics and food packaging. With these PLA’s adaptability and suitability in many techniques of production such as injection moulding, extrusion, and blow moulding, PLA has become high interest in the production process. Besides, PLA as a thermoplastic polyester that mostly obtained from renewable materials [1]. Infill patterns can affect the mechanical properties of 3D printed PLA and cPLA. PLA with zig zag infill pattern has higher tensile strength of 23.409 MPa compared to PLA with grid and concentric infill pattern. Meanwhile, cPLA with grid infill pattern has higher tensile strength of 30.5638 MPa compared to cPLA with concentric and zig zag infill pattern. By using the suitable infill pattern parameter, the 3D printed PLA and cPLA can have good mechanical properties and can be applied in packaging, pharmaceuticals, textiles, automotive, biomedical and tissue engineering. It has been widely investigated for biomedical applications due to its biodegradability and biocompatibility.

Tensor and Cartesian products for nanotori, nanotubes and zig–zag polyhex nanotubes and their applications to 13C NMR spectroscopy

We have developed novel topological techniques to generate distance degree vector sequences (DDS) and distance degree scalar sequences(SS) of tensor and Cartesian products of graphs. We establish that the tensor products of two distance degree regular graphs is distance degree regular. We apply the mathematical techniques thus developed for both tensor and Cartesian products to enumerate NMR signals and intensity patterns through the partitioning of equivalence classes accomplished by the use of distance degree vector sequences. In particular the techniques are applied to several nano materials such as carbon nanotori, monocyclic cylindrical nanotubes and zig–zag polyhex carbon nanotubes. It is shown that DDS sequences satisfactorily partition carbon vertices into equivalence classes for these nanomaterials. We also demonstrate applications of the developed techniques to diagrammatic representations of energy decompositions in molecular interactions.