Zigzag Pattern Research Articles

Numerical simulation and experimental verification for the sorting behaviors of mixed biomass particles in a novel Z-shaped fluidized bed

Inclined gas–solid fluidized bed has excellent particle separation and purification performance. Hence, Z-shaped fluidized bed as a novel fluidization system is designed in this work. The effect of superficial gas velocity on the sorting behaviors of mixed biomass particles is investigated by using the computational fluid dynamics and discrete element method, and a high-speed fluidization image experiment platform is established. The density and elastic modulus of biomass particles are experimentally measured, and the shapes are characterized by sphericity. Detailed information (i.e., distribution behavior and flow velocity of particle and fluid, particle residence time, and particle force) are obtained and analyzed. Results show that particles and fluid phases are not uniformly distributed, and a core-annulus structure is observed. The mixed particles movement process is divided into rising, settling, resuspension, and separation. The predictions on the solid distribution and sorting behaviors in the fluidized bed agree well with the experimental findings. Given the different densities and sizes, clean products flow upward and impurities flow downwards when the inlet air velocity is 1.5 m/s. As the superficial gas velocity increases, the transport efficiency of mixed particles improves, but the separation degree decreases. Clean products and impurities are effectively separated under the optimal gas velocity of 1.5–2.5 m/s. Particles in the channel center have a good following performance, moving in a zigzag pattern with the fluid, but they tend to slide along the inclined wall. The dynamic forces of the mixed particles are influenced by the channel section area. These findings provide valuable insight into the development and optimization of particle purification appliances in multiphase reactors.

In-depth field survey of a rockslide detachment surface to recognise the occurrence of gravity-induced cracking

This work describes field evidence of gravity-induced cracking that has been identified on the failure scar of a small rockslide (volume = 6–7 m3) that occurred in March 2004 in the Rosandra Valley near the town of Trieste (north-eastern Italy). This shallow rock slope failure involved a limestone slope that was re-profiled through blasting about 135 years ago for the construction of an old railway, which has now been reconverted into a cycle path. Field observations ascertained that the slope failure was characterised by a cascading rupture process in which adjacent blocks collapsed in rapid sequence as a result of the progressive breakage of a number of rock bridges (domino-like collapse), thus highlighting a progressive failure mechanism. The rock bridges were localised in eccentric positions on lateral and rear release planes and failed in tension as a result of combined tensile and bending loading conditions (tensile strength of intact rock = 5 ± 2 MPa). The rockslide was triggered by cyclic loading related to freeze-thaw (ice jacking) that occurred over some consecutive days of daily snowmelt and nocturnal frost. The recognition of newly formed fractures also proves the current progressive development of 3D rupture surfaces of some unstable blocks susceptible to failure. This study provides innovative content to detect gravity-induced cracking in the field, which is an important precursory sign relating to the progressive failure of rock slopes. Gravity-induced cracks can be distinguished from pre-existing discontinuities for their more irregular profile (zigzag pattern), rougher surface, lower persistence and potentially different orientation. This study also provides some new insights into the step-path failure process of steep rock slopes. The mechanical process of initiation, growing and coalescence of gravity-induced fractures is strongly time- and stress-dependent. In the absence of external changing factors that profoundly modify the acting stress state (for instance, engineering countermeasures), progressive failure is a dynamic and irreversible process. For excavated slopes, the creation of a new rock face may abruptly provide the kinematic freedom of potentially unstable blocks, thus determining a very quick stress redistribution. If the mechanical system is not able to redistribute the stress on resisting stiff parts without overcoming the intact rock strength, gravity-induced cracking initiates and propagates until reaching slope collapse within times that are much shorter (from hours to 100–200 years) compared to natural rock slopes subjected to long-lasting geological processes (from 1000 to 2000 up to 10,000–20,000 years).

Microscopic origins of anisotropy for the epitaxial growth of 3C-SiC (0001) vicinal surface: A kinetic Monte Carlo study

In order to investigate the microscopic evolution of the step flow growth process and reveal the microscopic origins of crystalline anisotropy during the epitaxial growth of 3C-SiC (0001) vicinal surface, a three-dimensional Kinetic Monte Carlo model is established, in which Si and C are considered individually. The helicoidal boundary condition is applied to the direction perpendicular to the step, and the periodic boundary condition is used in the direction along the step. Then, the effects of crystalline anisotropy on lateral growth rate, morphologies of step patterns, and growth mode are studied. The results show that the lateral growth rate in [1−210] is larger than that in ⟨1−100⟩, and the zigzag and meandering patterns of step are constructed in [1−210] and ⟨1−100⟩ directions, respectively, which is consistent with the experimental observations. Two possible origins of anisotropy are also revealed: one is the higher concentration of the edge sites of the step and the larger bonding energy in the [1−210] direction and another is the adatom diffusion along the edge of the step. Finally, a larger area of pure step flow growth mode is obtained in the [1−210] direction, which is good for lowering the cost for 3C-SiC epitaxial layers.

Tunable Friction Properties of Periodic Wrinkled BaTiO3 Membranes

AbstractThe wrinkled patterns may find potential applications in the areas that require tunable friction properties, such as flexible electronics, nanomechanical systems, and biomedical devices. However, the regulation of wrinkled patterns and the influence of friction property remain poorly understood, especially in the field of oxides. The epitaxial wrinkled BaTiO3 (BTO) membranes are prepared by the pulsed laser deposition and water‐dissolution process. The patterns, amplitude, and wavelength of the wrinkled BTO membranes are dependent on the thickness, pre‐stretched mechanical stress, and heat treatment. The friction properties of the wrinkled BTO membranes exhibit various anisotropic and periodic features due to the varying wrinkled patterns as applying different mechanical stress, including anisotropy with 180° angular periodicity, anisotropy with 360° angular periodicity, and isotropy, corresponding to the parallel, zigzag, and labyrinth patterns, respectively. Moreover, the heat process can further alter the magnitude of the friction property, showing a downward trend with increasing temperature. These results provide a better understanding of the friction properties of wrinkled patterns and pave a novel way to alter the friction properties for extensive applications.

Experimental study of the behaviour and failure modes of tapered castellated steel beams

Abstract This article discusses the experimental testing of tapered castellated beams (TCBs) under mid-span concentrated load. These beams are created by cutting the webs of standard I-sections in a particular zigzag pattern and rejoining the two parts by placing variable expansion plates between web posts and welding them together. Generally, the depth of the mid-span will be increased. A standard I-section (IPE140) was selected as a parent beam to fabricate three TCB specimens and one prismatic castellated beam. The experimental results showed that the ultimate load capacity of the TCBs could be increased up to 140% of the ultimate load capacity of the parent section. Fabricating a TCB is an effective way of increasing the allowable load of a long-span member while remaining within International Building Code-defined deflection limits. The experimental results showed that the allowable load at deflection (L/360) increased up to 183% of the allowable load for the control specimen at the same deflection. Finally, the experimental results showed that web-post buckling and joint-weld rupture failure modes occurred in TCBs due to the formation of high shear forces that tried to twist the web posts.

Bridge-weigh-in-motion approach for simultaneous multiple vehicles on concrete-box-girder bridges

Bridge-weigh-in-motion (BWIM) is a robust system that can accurately obtain traffic information to facilitate bridge design, maintenance, and management. However, the main issue with the existing BWIM approaches is their limited suitability for simultaneous multiple-vehicle cases on multiple-lane bridges. To address this limitation, in this study, a novel BWIM approach is proposed. The approach is built around the removal of the non-localized portion of the strain response. Keeping the localized portion of the strain response, which is not sensitive to nearby loads, allows for enhanced detection. The superiority of this approach stems from its capability to handle multiple-vehicle cases. These may present with an arbitrary number of trucks and light-weight vehicles, simultaneously passing the bridge in any arbitrary pattern or configuration. To show the applicability of the approach, a finite element (FE) model of a long-span concrete-box-girder bridge was simulated. The model was validated against the experimental data collected under known large events. The FE model was then used to consider single-truck events (for proof-of-concept) as well as complex multiple-truck traffic cases. These were including in-one-row trucks, zigzag patterns, side-by-side trucks, and a combination of several trucks with several light-weight vehicles present. The results demonstrated that the proposed BWIM approach is capable of obtaining the axle weights and gross vehicle weight (GVW) of the traversing trucks. Based on all complex multiple-truck cases, the overall mean absolute errors for GVW and axle weight estimations were 4.5% and 11.3%, respectively.

Thematic Structure and Thematic Progression in Research Articles Published in Scopus-Indexed International Journals

Publishing in highly-indexed journals is greatly competitive, thus writing a qualified and eligible text becomes more challenging for a second/foreign language writer of English. A good text should be written logically and organized effectively according to the role of good academic writing. Thematic structure and thematic progression contribute to the development of a well-structured meaningful text. This study examines the use of thematic structure and thematic progression in research articles published in Q1 and Q2 Scopus-indexed international journals as well as their relationship to achieve the texts’ coherence. This is a descriptive qualitative study within the framework of Systemic Functional Linguistics (SFL) that employs discourse analysis. 3426 clauses gathered from ten research articles were analyzed by using Halliday and Matthiessen’s (2014) taxonomy of thematic structure and Eggins’s (2004) theory of thematic progression. This study highlights three major findings. Firstly, in terms of thematic structure, the textual theme is massively used followed by the topical and interpersonal theme. The predominance of the textual theme implies the authors’ ability in developing the logical relations between clauses. Secondly, in terms of the thematic progression, the theme reiteration pattern is frequently employed, followed by the multiple-rheme and the zig-zag pattern. The tremendous use of the theme reiteration indicates the authors’ ability in maintaining the focus of the texts. Thirdly, the relationship between thematic structure and thematic progression constructs logical relations between the clauses to achieve the texts’ coherence. Finally, this study provides some pedagogical implications for the teaching of English as a second/foreign language.

Evaluation of Micro and Macro-level Coherence of Students Argumentative Essays in ESAWEEK Writing Competition

One of the most important aspects of writing a meaningful text is to achieve its coherence within the text. This study evaluated students' argumentative essays' micro and macro-level coherence in the ESA WEEK writing competition. This research is a qualitative study in the form of a discourse analysis approach by using the theory through the lens of micro and macro-level coherence (Thornburry, 2005). This study reveals several findings. Almost all the texts are sufficient to have good logical relations. The most frequent connections are additive and causal ties. In terms of logical relationships, the most frequent pattern in the texts was the zig-zag pattern, and the rarely used was the multiple rheme pattern. Even though all patterns were in texts, some rogue sentences were still found in each text. The keywords could represent the texts' topic or theme in almost every paragraph. It made readers guess the main issue quickly. Some writers could build a schema well, but others could not. Most of the texts organized in argumentative essays structure has Introduction-Body-Conclusion. This study can be used as a consideration to write meaningful and coherent text and references in the same field of discourse analysis.

A facile one-pot synthesis of a new 3,7-diethyl-1H- [1,2,4]triazino [4,3-b] [1,2,4]triazine-4,8-dione: Structural, thermal, and photoluminescent properties

A one-step condensation reaction of α-ketobutyric acid with diaminoguanidine in aqueous medium results in 3,7‑diethyl-1H- [1,2,4]triazino [4,3-b] [1,2,4]triazine-4,8‑dione. The newly formed compound was characterized by FT-IR, UV, 1H NMR, and 13C NMR spectroscopic techniques. The single-crystal X-ray structure of the compound was studied and showed crystallization in a monoclinic system C2/c with a = 22.70(2) Å, b = 5.028(5) Å, c = 17.802(16) Å, α = 90°, β = 93.96(3)°, γ = 90°, Z = 8, and R1/wR2 [I ≥ 2σ(I)] = R1 = 0.0461, wR2 = 0.0904. The structural units are surrounded by CH…O and NH…N interactions that generate zigzag patterns perpendicular to each other. The thermal reactivity and stability were analyzed by TG-DTA (thermogravimetry-differential thermal analysis) in both air and nitrogen atmospheres. In air, the compound showed an endothermic decomposition followed by exothermic combustion via triazine intermediate. In a nitrogen atmosphere, the compound showed endothermic decomposition followed by continuous combustion to produce gaseous products. This compound exhibited photoluminescent emission at λex = 380 nm.

Data Glove Using Soft and Stretchable Piezoresistive Sensors.

This research investigates the design and implementation of elastomer-based piezoresistive strain sensors and applies them to a data glove to demonstrate their application. The piezoresistive strain sensors are made by mixing Ecoflex 00-30 and carbon-black nanoparticles and then using stencil and doctor blading to deposit the piezoresistive traces as a mass fabrication technique. The primary objective is to integrate two sensing piezoresistive elements as one single-piece sensor that detects the bending angles of the metacarpophalangeal and proximal interphalangeal joints of each finger. Using a unique zig-zag pattern allows to selectively mask any unwanted piezoresistive sensing. The sensor has a gage factor of 0.68. Experiments conducted have demonstrated that the use of these soft, flexible, and stretchable piezoresistive sensors is repeatable and viable sensors for data-glove and has the potential for other wearable applications.

RETRACTED: The effect of the zigzag arrangement of lithium-ion batteries inside the air duct of an office building for heating and evaluation of the impact of the number of air outlets in different seasons of the year

This paper examines a hybrid battery system for heating an office building. Lithium cells have been one of the most common devices with high energy storage. However, the heat generated when they are placed close to each other has been a significant problem in these systems. A system is designed in this paper to use heat for heating a residential unit. The battery packs are placed inside the air duct, and each pack has 81 batteries 18,650. The batteries are arranged in a zigzag pattern. The airflow passes through the batteries, cools the batteries, and then is directed into the building. For each floor of the building, one of the ventilation units is considered with a battery. The model with three outlets causes the highest maximum temperature (TMax) of battery cells and the minimum heat transfer coefficient (HETC) among different models, while the 1-outlet one has the lowest TMax of battery cells and the maximum HETC. However, using the single-outlet model leads to the maximum pressure drop (ΔP), and the outlet air has the minimum temperature. At the same time, using the three-outlet model creates the minimum ΔP, and the outlet air temperature (TOutlet) has the maximum value. The model with 3 outlets can reduce the required heating energy consumption (ENC) by 23% in spring.

Study of electronic and mechanical properties of single walled Carbon nanotube (SWCNT) via substitutional Boron doping in zigzag and armchair pattern

Herein, we have studied the electronic and mechanical properties of Boron (B) doped (6,1) SWCNT in zigzag and armchair pattern by using Density Functional Theory (DFT) and ab−initio Molecular Dynamics (MD) simulations. A systematic periodic B-doping on (6,1) SWCNT was performed along with two different patterns: armchair(along the tube axis) and zigzag (along the tube curvature). The DFT calculations showed the dependence of the electronic properties of the SWCNT on the doping pattern as well as odd and even number of doping concentration. We also found the significant variation in mechanical response of the SWCNT tube on the dopant concentrations and doping patterns. Doping with one B atom enhanced the failure stress value by 70% but the Young’s modulus value reduced by 4.57% as compared with the pristine (6,1) SWCNT.

Development of a Microneedle Swab for Acquisition of Genomic DNA From Buccal Cells.

A swab is a tool for obtaining buccal DNA from buccal mucus for biological analysis. The acquisition of a sufficient amount and high quality of DNA is an important factor in determining the accuracy of a diagnosis. A microneedle swab (MN swab) was developed to obtain more oral mucosal tissues non-invasively. Eight types of MN swabs were prepared with varying combinations of patterns (zigzag or straight), number of MNs, intervals of MNs, and sharpness of tips. When MN swab was applied up to 10 times, the tissue amount and DNA yield increased compared to commercial swabs. A zigzag pattern of microneedles was found to be more efficient than a straight pattern and increasing the number of microneedles in an array increased the DNA yield. The MN swab collected about twice the DNA compared to the commercial swab. In an in vivo test using mini pigs, the lower cycle threshold values of mucosal samples collected with MN swabs compared to samples collected with commercial swabs indicated that a greater amount of DNA was collected for SNP genotyping. A polymer MN swab is easy to manufacture by a single molding process, and it has a greater sampling capacity than existing commercial swabs.

Comparing bowel lengthening procedures: which, when, and why?

Purpose of reviewIntestinal failure secondary to short bowel syndrome is still a very serious condition. Treatment consists of parenteral nutrition to provide nutrients and maintain body weight. During the last decades, intestinal lengthening procedures have become more available. The goal of this review is to discuss the results of the literature on the most commonly performed intestinal lengthening procedures.Recent findingsLongitudinal Intestinal Lengthening, Serial Transverse Enteroplasty (STEP), and Spiral Intestinal Lengthening and Tailoring (SILT) are currently the most frequently reported intestinal lengthening procedures. The most recent literature of these procedures is described with respect to indication, technical details, complications, short and long-term outcome, and PN independence.SummaryOn the basis of indication, surgical complexity, complications, and clinical success, we conclude that the STEP procedure is probably the best choice for most centers.

A spiral laser scanning routine for powder bed fusion inspired by natural predator-prey behaviour

ABSTRACT Additive manufacturing by laser powder bed fusion (LPBF) requires process parameters that consider both local and global thermal gradients to address material and component quality issues caused by non-uniform heating and cooling. Here, we develop an analogy between natural predator-prey behaviour and heat flow in LPBF, and consequently derive a spiral pattern that is translated into a discrete vector pattern compatible with LPBF. A power optimisation routine is applied to the spiral pattern to maintain constant melt pool depth, and the simulated thermal histories are compared to well-established zig-zag and helix scan patterns. From these results, we propose that the spiral pattern reduces the spatial variation of temperature, while a larger area remains above a specified threshold temperature at the end of the scan. Consequently, the spiral pattern may be promising for printing crack-prone materials, and for parameter optimisation of LPBF overall, and should be experimentally validated in future work.

Investigation on Residual Strength and Failure Mechanism of the Ceramic/UHMWPE Armors after Ballistic Tests

In this paper, the ballistic damage mechanism and residual bearing capacity of ceramic/backing plate armor were investigated. First, a series of lightweight armors were prepared, consisting of ceramic and ultra-high molecular weight polyethylene fiber-reinforced resin matrix composite (UHMWPE) plates, and were wrapped in a high-strength fabric. Then, the ceramic/UHMWPE armors were hit by one or two bullets, and finally subjected to compression testing. The results showed that the main failure mode of integral ceramic/UHMWPE armors was ceramic brittle fracture. Many zigzag patterns on the compression curve indicated that the specimens had undergone the stages of crack propagation, ceramic fragment reorganization, plastic deformation of UHMWPE backing plate, interlaminar tearing, and overall fracture. The failure of spliced ceramic/UHMWPE armors was mainly due to the dislocation between ceramic sheets; the smooth compression curves indicated that there was no recombination of ceramic fragments and obvious interlayer debonding during the compression. Under the maximum load, each ceramic/UHMWPE armor with ballistic damage did not suddenly break and fail. The structure and thickness of ceramic plates all had an impact on residual strength: under the same structure, the greater the thickness, the greater the residual strength, but the relationship between them was not linear; under the same thickness, the residual strength of the spliced ceramic/UHMWPE armor was higher. The residual strength was also related to the number of shots: after two bullets hit, its value was only one-third of that after one bullet hit.

Generation of continuous hybrid zig-zag and contour paths for 3D printing

The generation of the printing paths is a decisive step in additive manufacturing (AM). There is a variety of patterns that offer different characteristics, but those that are strictly continuous become especially relevant in certain types of AM by extrusion, with materials like bioinks, carbon or clays, since they do not allow the retraction of the material and travelling movements result in the generation of artifacts. In this work, we present (1) a method that generates continuous paths to fill 2D polygons with a hybrid zig-zag and contour pattern with any direction and line separation, which extends an algorithm that decomposes the 2D area to be filled into convex areas, overcoming its limitations to generate less subpolygons in certain cases, (2) a method to join the subpolygon trajectories such that a continuous path that fills the whole polygon is obtained, and (3) a publicly available dataset containing (a) a set of 2D polygons that are relevant to test the performance of the algorithms and (b) the results of filling those polygons with our methodology. Results show that the developed methods produce satisfactory results for the polygons contained in the evaluation dataset, including a couple of demonstrations of real 3D prints with the generated trajectories. Further work is needed to extend the methodology to produce suitable solutions for polygons with curved holes.

FINANCIAL SUSTAINABILITY AND FINANCIAL REPORTING PRACTICES IN DEVELOPING COUNTRIES: EVIDENCE FROM IRAQ

This study seeks to discover the nature of the link between the financial reporting methods used by nonprofit organizations in Iraq and their long-term financial viability. NPO financial reporting methods now are not consistent with their nature. According to the exploratory study, they do not satisfy stakeholder expectations, which also shows that the general assessment of the financial reporting system of Iraqi NPOs is inadequate. For the three years, 2015-2017, data from a study of 70 Iraq-registered NGOs shows that most financial sustainability metrics were poor, except the current ratio, which shows that 69% of NPOs had sufficient cash. However, when it comes to solvency (39%) and saving (19%) as well as defensive interval, the data show a zigzag pattern of decrease (46 percent ). As a result of inadequate Iraqi financial reporting standards and low economic sustainability indicators, the study concludes that nonprofit organizations' financial reporting system is integrated with financial sustainability

Size quantification of non-spherical bubbles by ultrasound

Ultrasonic detection is an effective method to quantify bubbles in opaque liquid, and acoustic scattering model is the key in ultrasonic inversion technique. Classical scattering models are usually based on the spherical assumption and <em>ka</em> is much less than 1. However, these conditions are not always satisfied in practical applications. In this study, a quantitative strategy of ultrasonic inversion is proposed for non-spherical bubbles and <em>ka</em> deviation assumption. A series solution model for a spherical gas bubble is established without considering the <em>ka</em> constraint, and it was compared with the classical Medwin (<em>ka</em><<1) and Anderson (<em>ka</em>≈1) models. The difference in their scattering cross sections <em>σ<sub>bs</sub></em> is only at the higher order formants of scattering and so the fitted line can be used to solve the multi-valued problem between <em>σ<sub>bs</sub></em> and <em>ka</em>. For a non-spherical bubble, <em>σ<sub>bs</sub></em> is determined by the frequency domain backscattering signal and size is characterized by the equivalent radius<em> a</em><sup>*</sup>and the inversion is performed by fitted curve from series solution model. Ultrasonic quantitative results were examined by high-speed photography. Results show that bubble rises in a zigzag pattern and non-spherical bubbles, their scattering cross sections are measured by the frequency domain scattering signal obtained at a position of ultrasonic measurement and the equivalent radius is inverted by the series solution fitting curve. The deviation between the results and the actual results <em>r</em><sub>0</sub> is about 1mm(relative error less than 45%) when 9≤<em>kr</em><sub>0</sub>≤35. This method can be used for acoustic inversion of non-spherical bubbles in a certain range of measurement accuracy.

New Benchmark Functions for Single-Objective Optimization Based on a Zigzag Pattern

Benchmarking plays a crucial role in both development of new optimization methods, and in conducting proper comparisons between already existing methods, particularly in the field of evolutionary computation. In this paper, we develop new benchmark functions for bound-constrained single-objective optimization that are based on a zigzag function. The proposed zigzag function has three parameters that control its behaviour and difficulty of the resulting problems. Utilizing the zigzag function, we introduce four new functions and conduct extensive computational experiments to evaluate their performance as benchmarks. The experiments comprise of using the newly proposed functions in 100 different parameter settings for the comparison of eight different optimization algorithms, which are a mix of canonical methods and best performing methods from the Congress on Evolutionary Computation competitions. Using the results from the computational comparison, we choose some of the parametrization of the newly proposed functions to devise an ambiguous benchmark set in which each of the problems introduces a statistically significant ranking among the algorithms, but the ranking for the entire set is ambiguous with no clear dominating relationship between the algorithms. We also conduct an exploratory landscape analysis of the newly proposed benchmark functions and compare the results with the benchmark functions used in the Black-Box-Optimization-Benchmarking suite. The results suggest that the new benchmark functions are well suited for algorithmic comparisons.