Miracle-dz/UniFAR-FTUs huggingface dataset:
Predicting strength of SCC using artificial neural network and multivariable regression analysis

In the present study an Artificial Neural Network (ANN) was used to predict the compressive strength of self-compacting concrete. The data developed experimentally for self-compacting concrete and the data sets of a total of 99 concrete samples were used in this work. ANN\'s are considered as nonlinear statistical data modeling tools where complex relationships between inputs and outputs are modeled or patterns are found. In the present ANN model, eight input parameters are used to predict the compressive strength of self-compacting of concrete. These include varying amounts of cement, coarse aggregate, fine aggregate, fly ash, fiber, water, super plasticizer (SP), viscosity modifying admixture (VMA) while the single output parameter is the compressive strength of concrete. The importance of different input parameters for predicting the strengths at various ages using neural network was discussed in the study. There is a perfect correlation between the experimental and prediction of the compressive strength of SCC based on ANN with very low root mean square errors. Also, the efficiency of ANN model is better compared to the multivariable regression analysis (MRA). Hence it can be concluded that the ANN model has more potential compared to MRA model in developing an optimum mix proportion for predicting the compressive strength of concrete without much loss of material and time.
A Periodic Deformation Mechanism of a Soft Actuator for Crawling and Grasping

Periodic locomotion in nature has provided many inspirations for soft actuators. Compared with rigid actuators, soft actuators can transform into versatile shapes to adapt to different working environments and are able to interact with the human in a safer manner because of their compliance. However, soft actuators often suffer from complex structures designs and complicated sequences of stimuli to achieve periodic locomotion. To overcome this shortcoming, a periodic deformation mechanism based on strain energy storing is proposed in this paper. Guided by this mechanism, a simple soft actuator is designed without complicated control systems. The soft actuator involves shape memory alloy and silicon rubber. Crawling and grasping of the soft actuator are achieved by electrical heating methods. The proposed mechanism can provide inspiration for the design of soft actuators, smart wearable equipment, and medical devices.
Computer aided design of water-resistant adsorbent for formaldehyde abatement

Formaldehyde is a well-known indoor air pollutant that is regulated by authorities worldwide. Formaldehyde has adverse health effects in humans, especially as a sensory irritant to the eyes and to the upper air way, and more importantly, it is a known carcinogen. Adsorption by carbon adsorbents is an old, but indispensable cleaning technology for combating indoor formaldehyde. In this study, we report isotherms and 2D-density distributions by conducting comprehensive Monte Carlo simulation. The effects of the functional group and pore size were investigated. We found that formaldehyde has a different response when the number of functional group and pore size change from that of water. Therefore, by tuning pore size and functionalities it may be feasible to produce real materials that retain effective capture of formaldehyde but which avoid pore blocking by water based on the differences in adsorption properties between water and formaldehyde.
Sandwich plates with gradient lattice cores subjected to air blast loadings

Abstract The dynamic responses of multi-layer gradient pyramid lattice sandwich plates subjected to blast loadings were investigated by employing numerical simulation method in this paper. The relative densities of core layers were adjusted by varying cross-sectional dimensions of lattice truss. Six kinds of gradient configurations were proposed based on the arrangement of various lattice core layers. The mechanical properties of 304 stainless steel used in this analyses were simulated using rate-dependent JC constitutive model, and the blast loadings were imposed to the sandwich structures using CONWEP loading mode. The validation of the simulation approach was studied by a comparison of simulation results with the existing experimental results from the literature. The back sheet deflection and the support reaction were analyzed to evaluate the blast resistance of multi-layer gradient sandwich structures. It can be found that the gradient configuration, of which relative density of core layer increases layer by layer from front sheet to back sheet, has the most excellent blast resistance. The dynamic response of gradient lattice sandwich structures in the case of different standoff distances and different explosive charges were calculated. And the relationships between intensity of load and blast resistance of the gradient sandwich structures with pyramid lattice core were analyzed.
Grain Boundary Processes in Strengthening, Weakening, and Superplasticity

Grain boundaries provide strength to materials at low temperatures by impeding slip transfer and they weaken materials at high temperatures by intergranular creep processes such as grain boundary sliding (GBS) and diffusion creep. At very fine nanocrystalline grain sizes of <10 nm, it is possible to observe grain boundary weakening rather than strengthening at room temperature. Superplastic flow is observed in a wide range of materials, but the common phenomenology of a high strain rate sensitivity and extensive GBS may arise from varying importance of GBS accommodated by dislocations, diffusion creep, and interface‐controlled diffusion creep. Thus, superplasticity in metals and ceramics involves GBS with dislocation accommodation and interface‐controlled diffusion creep, respectively. It is recognized that grains retain their equiaxed shapes during diffusion creep by grain switching and grain growth. Ultrafine‐grained and nanocrystalline materials with a high strain rate sensitivity of >0.3 deform with a large GBS contribution to total strain of ≈40–80%. There are a limited number of studies showing superplasticity in fine‐grained high‐entropy alloys, involving GBS accommodated by dislocations.
Study on the Design of Cutting Disc in Ultrasonic-assisted Machining of Honeycomb Composites

To study the influences of geometrical parameters on the design of ultrasonic-assisted cutting disc tool for honeycomb composites, a finite element model integrating the cutting disk and ultrasonic horn was established. The performance of the output amplitude of the cutting disc was analyzed under different geometrical parameters including cutter radius, cutter thickness and anterior angle. Then the influences of the geometrical parameters on the energy density and bending rigidity of the cutting disc were discussed. The simulation results shown that with the increase of cutter radius, both the energy density and rigidity decreased, and the amplitude at the cutting edge increased firstly and then decreased under the interaction of the energy density and rigidity. There was an ideal interval of radius within which the amplitude reached the maximum. With the increase of cutter thickness and anterior angle, the energy density decreased while the rigidity increased, the amplitude at the cutting edge presented a declining trend.
Graphene: Structure, Synthesis, and Characterization; a brief review

In 2004, Andrei Geim and Kostya Novoselov used a simple technique to separate graphene layer from graphite. They were awarded the Nobel Prize in Physics in 2010. After this, the publications of graphene have been increasing year after year and have emerged as the most popular topic in the research field which indicates the importance of graphene research. Due to unique properties of graphene, it can be considered as promising material for various applications in the fields of physics, chemistry, material science and engineering, and biology. Consequently, this review will focus on using of biomass and other wastes as precursor material for graphene preparation. We hope it could be of any help to people who are interested in this field. The future outlook of graphene is also considered.
2-Dimensional Mapping of Damage in Moisture Contaminated Polymer Composites Using Dielectric Properties

Polymer composite materials are increasingly being adopted in civil infrastructure, oil & gas, marine, automotive and aerospace industries. Achieving ubiquitous adoption would require new advances in development of non-destructive examination methods which are cost effective relative to composite structures under test, simple to utilize and sensitive enough to ascertain the structural integrity of composite parts, especially in the absence of visible damage. This study proposes a relatively simple method for non-destructive testing of polymer composites that detects 2-dimensional micro to nano-scale damage by analysis of the effects of polymer-moisture interactions on microwave-frequency dielectric properties. In this study, we apply this method to mapping of internal damage in two widely used aerospace composite laminates; a 12-ply bismaleimide/quartz and a 16-ply epoxy/7781 fiber glass composite laminate. Specimens are dried and then immersed in deionized water, to simulate long term exposure to humid environments while measuring gravimetric moisture uptake. Localized damage is induced in the laminate specimens via low velocity impact damage of 5 and 9 Joules. A split post dielectric resonator coupled with a vector network analyzer is used to determine the spatial variation in relative permittivity across the composite laminate. Generally, results show significant increase in relative permittivity towards the center of impact damage compared to surrounding undamaged areas. This increase is indicative of internal damage as a result of micro-crack formation around the point of impact. This new free volume in the damaged area is primarily occupied by free water; driving a local increase in the relative permittivity in the damaged area due to the locally-higher ratio of free to bound water.
Characterization of heterogeneous InP-on-Si optical modulators operating between 77 K and room temperature

Heterogeneous integration of InP modulators on a silicon photonic platform, fabricated by bonding III–V wafer on patterned silicon waveguides, are proved to work between 77 K and 295 K. The performance of modulators based on the Franz-Keldysh effect (bulk) and the quantum confined Stark effect (quantum-well) is investigated for wavelengths ranging within 1460 nm–1580 nm. The bulk modulator is preferred when operating over a wide range of temperatures. The demonstration of such integrated optical components at low temperatures is especially attractive for applications that demand massive data communication between cryogenic and room temperatures requiring photonic interconnect, as well as applications with extreme environmental conditions, such as outer space exploration.
Study on Mist Nozzle Spray Characteristics for Cooling Application

Evaporative cooling mist spray is a cost effective solution for many cooling applications. Selection of misting spray nozzle play a major role in order to provide the suitable spraying condition in regards to the application. One of the most widely use mist spray application is evaporative cooling of outdoor open area. This study was carried out to characterized the spray formation, size of droplet, velocity of the droplet and the angle of the spray formation from a commercial mist spray nozzle namely 1/8 SF-CE SM nozzle with 1 mm and 2 mm diameter hole. Water was supplied with different pressure of 1, 2 and 4 bar. High speed video camera and still digital camera using short burst of flash were used to produce the video and image for analysis. The results show that increase in water pressure affect the spray angle, increase droplet speed and decrease droplet size of the mist spray.
Building Blocks Development for Defect-Free Growth of GaAs on Silicon for Tandem Solar Cells

: The monolithic integration on silicon of GaAs, and more generally of III-V semiconductors, is a very attractive and promising route for the production of high efficiencies multijunctions devices in the manner of those developed for space applications on germanium, but at a much lower cost suitable for terrestrial PV applications. The purpose of this paper is to present the building blocks we have developed for defect-free growth of GaAs on silicon for tandem solar cell applications. This will be addressed from the technological point of view as well as from design, modelling and characterization perspectives. Preliminary work has allowed the identification of critical technological bottlenecks, following which solution routes have been developed as will be presented and discussed. The resulting design for a GaAs/Si tandem solar cell will then be described.
Trisialo-Fe 2 -Transferrin Does Not Improve the Diagnostic Accuracy of Carbohydrate-deficient Transferrin as a Marker of Chronic Excessive Alcohol Intake

We studied the diagnostic efficiency of two commercial tests for analysis of carbohydrate-deficient transferrin (CDT) as a marker of chronic alcohol abuse in alcoholics, %CDTri-TIA (which includes about 50% trisialo-Fe2-transferrin in CDT) and ChronAlcoI.D. (which excludes this transferrin isoform of CDT). TLFB (Timeline-Followback) and Composite International Diagnostic Interview (CIDI) 2.1-alcohol section, which are valid, reliable and fully structured diagnostic interviews, were used as gold standard for assessment of frequency and amount of alcohol intake. %CDTri-TIA showed a distinctly reduced diagnostic sensitivity (%CDTri-TIA, 52,8%: ChronAlcoI.D. 71,7%; p = 0,00) and accuracy (%CDTri-TIA, 66,2%: ChronAlcoLD., 77,9.%; p = 0,01). Diagnostic specificity was . statistically not different between the tests (%CDTri-TIA, 95,8%; ChronAlcoI.D., 91,7 %; p = 0,30). Inclusion of trisialo-Fe2-transferrin in CDT does not improve its diagnostic efficiency.
Local plasmons contribution into photocurrent of Au/GaAs surface barrier structure with Au nanoparticles on interface

Au/SiO2 core-shell nanoparticles have been used to increase the photocurrent in the surface barrier structure Au/GaAs. The method for theoretical calculation of interaction between light and the system of ordered nanoparticles placed on the surface barrier structures has been proposed. Local plasmons excited in the nanoparticles produce additional carriers due to scattering, prolonged interaction with semiconductor and enhanced evanescent electromagnetic field, thus they increase the photocurrent.
Efficient isogeometric finite element formulations for coupled systems on deforming surfaces

This thesis presents various isogeometric finite element formulations for the efficient computation of coupled systems on deforming surfaces. The surface deformation is described by the Kirchhoff-Love thin shell equation, which is a fourth-order nonlinear partial differential equation (PDE). A curvilinear surface parameterization is used throughout the proposed formulations to allow for general surface shapes and deformations. In the first part of this thesis, a novel adaptive local surface refinement technique based on locally refinable non-uniform rational B-splines (LR NURBS) is presented. For a convenient embedding into general finite element codes, the Bézier extraction operator for LR NURBS is formulated. An automatic remeshing technique is presented that allows adaptive local refinement and coarsening of LR NURBS. This technique is applied to frictionless and frictional sliding contact of deforming thin shells. Several numerical examples demonstrate the benefit of LR NURBS: Compared to uniform refinement, LR NURBS can achieve high accuracy at lower computational cost. In the second part of this thesis, a general theory and isogeometric finite element formulation for studying mass conserving phase transitions on deforming thin shells is presented. The mathematical problem is governed by the coupling of the Kirchhoff-Love shell PDE with the Cahn-Hilliard PDE for phase transitions, which can be derived from surface mass balance in the framework of irreversible thermodynamics. The coupling leads to a system of two fourth-order nonlinear PDEs, that live on an evolving two-dimensional manifold. Structured NURBS and unstructured spline spaces are utilized for these interpolations. In order to use multi-patch NURBS discretizations, an approach for continuity constraints at patch interfaces is proposed. The resulting finite element formulation is discretized in time by the generalized-α scheme. An adaptive time stepping approach is presented and the coupled system is fully linearized within a monolithic Newton-Raphson approach. The behavior of the coupled system is illustrated by several numerical examples exhibiting phase transitions on deforming tori and spheres. Within the last part of this thesis, an adaptive phase field formulation for dynamic fracture of brittle shells is presented. The fracture evolution equation employs a fourth-order phase field formulation and bases on Griffith’s theory of brittle fracture. This fourth-order PDE is coupled with the Kirchhoff-Love shell PDE. LR NURBS are used for the surface discretization. The temporal discretization is based on the generalized-α scheme and the discretized coupled system is solved within a monolithic Newton-Raphson scheme. The proposed formulation is fully adaptive in space and time, by using an adaptive local refinement approach and an adaptive time stepping scheme. The interaction between surface deformation and crack evolution is demonstrated by several numerical examples.
On mechanical characterization of 3-D printed PLA-PVC-wood dust-Fe3O4 composite

In recent past, fused deposition modeling (FDM)-based functional prototypes have been explored in printing of composites for 4-D applications as smart thermoplastics. The 3-D printed parts with 4-D properties have wide utility in structural/nonstructural engineering applications. Some studies have reported preparation of feedstock filament as composite material comprising of polylactic acid (PLA) reinforced with polyvinyl chloride (PVC), wood dust, and magnetite (Fe3O4). But hitherto very little has been reported on mechanical characterization of 3-D printed PLA-PVC-wood dust-Fe3O4 composite. The present work is an extension of study reported on mechanical and magnetic properties-based characterization of feedstock filament prepared for FDM, to understand the effect of processing parameters on properties of functional prototypes in structural/nonstructural engineering applications. For mechanical characterization, analysis of variance (ANOVA) and historical data approach have been used in optimization of 3-D printing condition in two stages. From ANOVA, it has been figured out that infill density of 100%, infill angle of 45°, and infill speed of 70 mm/s have given best result for peak strength and break strength in first stage. Further, the results of ANOVA model suggested that either there were some missing independent variables or interaction of present variables with each other was playing role in output. In second stage, historical data approach was used to understand the affect of interactions present among the input variables. The morphological analysis suggested that the sample printed with maximum density and low infill angle has minimum porosity and thus shows better mechanical properties. The results were supported with photomicrographs to understand the effect of porosity in the fractured sample.
Semiconductor Nanofabrication via Metal-Assisted Chemical Etching: Ternary III-V Alloys and Alternative Catalysts

Kate Gleason College of Engineering Rochester Institute of Technology Degree: Doctor of Philosophy Program: Microsystems Engineering Author’s Name: Thomas S. Wilhelm Advisor’s Name: Parsian K. Mohseni, Ph.D. Dissertation Title: Semiconductor Nanofabrication via Metal-Assisted Chemical Etching: Ternary III-V Alloys and Alternative Catalysts The increasing demand for complex devices that utilize three-dimensional nanostructures has incentivized the development of adaptable and versatile semiconductor nanofabrication strategies. Without the introduction and refinement of methodologies to overcome traditional processing constraints, nanofabrication sequences risk becoming obstacles that impede device evolution. Crystallographic wet-chemical etching (e.g., Si in KOH) has historically been sufficient to produce textured Si surfaces with smooth sidewalls, though it lacks the ability to yield high aspect-ratio features. Physical and chemical plasma etching (e.g., reactive-ion etching) evolved to allow for the creation of vertical structures within integrated circuits; however, the high energy ion bombardment associated with dry etching can cause lattice and sidewall damage that is detrimental to device performance, particularly as structures progress within the microand nano-scale regimes. Metal-assisted chemical etching (MacEtch) provides an alternative processing scheme that is both solution-based and highly anisotropic. This fabrication method relies on a suitable catalyst (e.g., Au, Ag, Pt, or Pd) to induce semiconductor etching in a solution containing an oxidant and an etchant. The etching would otherwise be
Graded index fiber as an all-fiber saturable absorber for large energy conventional soliton and dissipative soliton generation

In this work, we investigate the possibility of achieving nanojoule level pulse energy in an all-fiber Er-doped oscillator by using a graded index multimode fiber (GIMF) as the saturable absorber (SA). This GIMF-based SA demonstrates the desirable characteristics of high-power tolerance, large modulation depth of 29.6%, and small saturation fluence of ∼7.19×10−3 μJ/cm2, which contribute to the high-energy soliton generation. In the experiments, the oscillator generates stable ultrafast pulse trains with high pulse energy/average output power up to 13.65 nJ/212.4 mW in the anomalous regime and 6.25 nJ/72.5mW in the normal regime, which are among the highest energy/average output power values achieved by all-fiber Er lasers. The results obtained demonstrate that the GIMF-based SA can be used as an effective photonic device for high-energy wave-breaking free pulse generation.
Effect of adding nano-calcined clay and nano-lime on the geotechnical properties of expansive clayey soil

The objective of this paper is to investigate the effect of nano-calcined clay (NCC) and nano-lime (NL) on some engineering properties of the expansive clayey soil. Three soil samples quarried from three different sites in the south of Syria have been investigated. They were thermally treated up to three different levels (450, 650 and 850°C) for 3 hours. Then, they were ground to have a particle size of less than 100 nano-meter. Three replacement levels of NCC were used, i.e. 0%, 1% and 2%. XRD technique has been employed to detect the phases occurring in the clayey samples before and after the thermal treatment. Pozzolanic activity of the calcined clayey soil has been studied using the modified Chapelle test. Atterberg limits, compaction, free swell, swelling pressure, linear shrinkage, shear strength and CBR have particularly been investigated. Test results revealed the positive effect of NCC. Plasticity index (PI) was reduced by more than 50% when 2% NCC was added to the natural soil. In addition, 0.6% NL was added to further investigate the combined effect of NL and NCC on the properties of the clayey soil. All investigated properties were significantly improved when NCC and NL were added together, i.e. swelling pressure and linear shrinkage values were reduced to less than 15% when compared with those of the natural soil.