Hybrid deposition additive manufacturing: novel volume distribution, thermo-mechanical characterization, and image analysis

(c) The Author/sCAUL read and publish agreement 2022The structural integrity of additive manufacturing structures is a pronounced challenge considering the voids and weak layer-to-layer adhesion. One of the potential ways is hybrid deposition manufacturing (HDM) that includes fused filament fabrication (FFF) with the conventional filling process, also known as “HDM composites". HDM is a potential technique for improving structural stability by replacing the thermoplastic void structure with a voidless epoxy. However, the literature lacks investigation of FFF/epoxy HDM-based composites regarding optimal volume distribution, effects of brittle and ductile FFF materials, and fractographic analysis. This research presents the effects of range of volume distributions (10–90%) between FFF and epoxy system for tensile, flexure, and compressive characterization. Volume distribution in tensile and flexure samples is achieved using printable wall thickness, slot width, and maximum width. For compression, the printable wall thickness, slot diameter, and external diameter are considered. Polylactic acid and acrylonitrile butadiene styrene are used to analyze the brittle and ductile FFF structures. The research reports novel application of image analysis during mechanical characterization using high-quality camera and fractographic analysis using scanning electron microscopy (SEM). The results present surprising high tensile strain (0.038 mm/mm) and compressive strength (64.5 MPa) for lower FDM-percentages (10%, 20%) that are explained using in situ image analysis, SEM, stress–strain simulations, and dynamic mechanical analysis (DMA). In this regard, the proposed work holds novelty to apply DMA for HDM. The optimal volume distributions of 70% and 80% alongside fractographic mechanisms for lower percentages (10%, 20%) can potentially contribute to structural applications and future material-based innovations for HDM.fals

Exploring thermoelectric materials for renewable energy applications: The case of highly mismatched alloys based on AlBi1-xSbx and InBi1-xSbx

The high throughput thermoelectric devices are considered promising futuristic energy source to control global warming and realize the dream of green energy and sustainable environment. The ability of the highly mismatched alloys (HMAs), to show the intriguing impact on the physical properties with controlled modifications, has extended their promise to thermoelectric applications. Here, we examine comprehensively the potential of the two prototypical HMAs such as AlBi1-xSbx and InBi1-xSbx for thermoelectric applications within density functional theory together with the Boltzmann transport theory. For comprehensive understanding, alloying of these materials has been performed over the entire composition range. From our calculations, we found, the replacement of Sb with Bi leads to a significant evolution in the energy band-gap and effective masses of the charge carriers that consequently deliver enhancement in thermoelectric response. Improvement of magnitude 1.25 eV and 0.986 eV has been respectively recorded in band-gaps of AlBi1-xSbx and InBi1-xSbx for the across composition alloying. Similarly, by the electronic-structure engineering of HMAs, thermoelectric properties such as, the Seebeck coefficients over Fermi-level were found to be improved from 82.90 µV/K to 107.52 µV/K for AlBi1-xSbx and 60.32 µV/K to 92.73 µV/K for InBi1-xSbx. As a result, the thermoelectric figure of merit (ZT) and power factor show considerable enhancement as a function of alloying composition for both alloys at room temperature. However, at a higher temperature, the thermal conductivity of these materials experience an exponential increase, results in lower ZT values. Overall, the observed evolution in the electronic structure and thermoelectric response for replacing Sb over Bi is significant in AlBi1-xSbx as compared to InBi1-xSbx. Hence, with the capability of significant and controlled evolution in electronic-structure and subsequent thermoelectric properties, HMAs particularly AlBi1-xSbx are believed potential candidates for thermoelectric applications

Cultural References in Films: An Audience Reception Study of Subtitling into Arabic

This article focuses on the issue of capturing cultural references in subtitled translations. It addresses three shortcomings in current translation scholarship. First, most of the studies in audiovisual translation focused on cultural references are primarily based on European languages and contexts. Second, the typologies resulting from those studies focus solely on verbal references and often ignore the multimodal meaning-making situation in which cultural references are construed or their non-verbal nature. Third, most of the extant studies on the translation strategies used are descriptive, rather than grounded in empirical reception studies. This article will report and discuss the data collected on an experimental study examining the reception of cultural references on films subtitled into Arabic. It will revisit the traditional understanding of cultural references as limited to the verbal mode and examine the impact of domesticating and Foreignisation methods on Saudi-Arabian viewers’ meaning-making process

New Trends in Nuclear Science

This book will hopefully shed light on some of the advances taking place within nuclear science research in recent times. It describes the interesting results of some modern nuclear science research carried out by bright scientists and researchers in different parts of the world. The book is divided into five chapters. The first one is an introductory chapter to explain the nature and purpose of the book and the logic and significance of its contents. The second chapter is a concise introduction to the core subject of nuclear science, which is the nuclear reactions. This chapter also touches on the fundamental and basic physics underlining major nuclear reactions. Chapter three addresses some recent advances related to the famous nuclear detector material namely CdTe. The authors suggest that the modern detector based on CdTe materials can be developed as a multi-element detection platform that allows for the direct conversion of information generated by passing X/y-radiations through an examined object into an array of digital electrical signals without using an intermediate visible image on a fluorescent screen. In chapter four, a new study on the effect of unintended and accidental nuclear impact on the environment is discussed. In the last chapter, Thomas W. Grimshaw; from The University of Texas at Austin, USA; has composed an interesting study on the so-called cold nuclear fusion or the more widely known low energy nuclear reaction (LENR). He, among others, argues that nuclear cold fusion, if realized and understood, could be a significant source of cheap and clean energy. This book will hopefully encourage readers, researchers, and scientists to look further into the frontier topics of modern nuclear science and make the needed efforts to develop its cause and uses

Exploring the thermoelectric response of novel polymorphs of ZnO for renewable energy applications using first-principles approaches

The inexpensive, earth abundant, and non-toxic thermoelectric materials are relentlessly demanded to realize the dream of sustainable energy and overcome the energy crisis. To do so, a lot of studies are being conducted on different materials at different levels. However, the energy crisis is still a big challenge. Some polymorphs of zinc oxide (ZnO) being cheaper, non-toxic, and exhibiting good thermoelectric response at high temperatures have shown its adequate potential to play a role in sustainable energy technologies. In this study, we attempt to explore the thermoelectric response of different types of ZnO polymorphs named as sphalerite, wurtzite, CsCl, NiAs, GeP, BeO, 5-5 type versus chemical potential and temperature and the study is carried out by full-potential (FP) linearised (L) augmented plane wave (APW) plus local orbitals ( lo) (FPL(APW+lo) approach structured within density functional theory (DFT) and Boltzmann transport theory. Our obtained results of thermoelectric power factors for sphalerite, wurtzite, CsCl, NiAs, GeP, BeO, 5-5 type of the polymorphs of ZnO are recorded as 8.04 x 10(11) W/mK(2)s, 7.01 x 10(11) W/mK(2)s, 11.7 x 10(11) W/mK(2)s, 4.90 x 10(11) W/mK(2)s, 4.97 x 10(11) W/mK(2)s, 2.28 x 10(11) W/mK(2)s, and 5.31 x 10(11) W/mK(2)s respectively. Hence, the considered polymorphs of ZnO have been found to exhibiting the great potential to replace expensive, rare, and toxic thermoelectric materials

Exploring single-layered SnSe honeycomb polymorphs for optoelectronic and photovoltaic applications

Single-layered tin selenide that shares the same structure with phosphorene and possesses intriguing optoelectronic properties has received great interest as a two-dimensional material beyond graphene and phosphorene. Herein, we explore the optoelectronic response of the newly discovered stable honeycomb derivatives (such as α, β, γ, δ, and ɛ) of single-layered SnSe in the framework of density functional theory. The α, β, γ, and δ derivatives of a SnSe monolayer have been found to exhibit an indirect band gap, however, the dispersion of their band-gap edges demonstrates multiple direct band gaps at a relatively high energy. The ɛ-SnSe, however, features an intrinsic direct band gap at the high-symmetry Γ point. Their energy band gaps (0.53, 2.32, 1.52, 1.56, and 1.76 eV for α-, β-, γ-, δ-, and ɛ-SnSe, respectively), calculated at the level of the Tran-Blaha modified Becke-Johnson approach, mostly fall right in the visible range of the electromagnetic spectrum and are in good agreement with the available literature. The optical spectra of these two-dimensional (2D) SnSe polymorphs (besides β-SnSe) are highly anisotropic and possess strictly different optical band gaps along independent diagonal components. They show high absorption in the visible and UV ranges. Similarly, the reflectivity, refraction, and optical conductivities inherit strong anisotropy from the dielectric functions as well and are highly visible-UV polarized along the cartesian coordinates, showing them to be suitable for optical filters, polarizers, and shields against UV radiation. Our investigations suggest these single-layered SnSe allotropes as a promising 2D material for next-generation nanoscale optoelectronic and photovoltaic applications beyond graphene and phosphorene

Defect engineering for enhanced optical and photocatalytic properties of ZnS nanoparticles synthesized by hydrothermal method

Abstract Defect engineering is a promising method for improving light harvesting in photocatalytic materials like Zinc sulphide (ZnS). By altering the S/Zn molar ratio during hydrothermal processes, Zn and S defects are successfully introduced into the ZnS crystal. The band structures can be modified by adding defects to the crystal structure of ZnS samples. During the treatment process, defects are formed on the surface. XRD and Raman studies are used for the confirmation of the crystallinity and phase formation of the samples. Using an X-ray peak pattern assessment based on the Debye Scherer model, the Williamson-Hall model, and the size strain plot, it was possible to study the influence of crystal defect on the structural characteristics of ZnS nanoparticles. The band gap (Eg) values were estimated using UV–Vis diffuse spectroscopy (UV–Vis DRS) and found that the Eg is reduced from 3.28 to 3.49 eV by altering the S/Zn molar ratio. Photoluminescence study (PL) shows these ZnS nanoparticles emit violet and blue radiations. In keeping with the results of XRD, TEM demonstrated the nanoscale of the prepared samples and exhibited a small agglomeration of homogenous nanoparticles. Scanning electron microscopy (SEM) was used to examine the surface morphology of the ZnS particles. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and X-ray photoelectron spectroscopy (XPS) were used to evaluate and validate the elemental composition. XPS results indicate the presence of defects on the prepared ZnS nanoparticles. For the investigation of vacancy-dependent catalytic activity under exposure to visible light, defective ZnS with different quantities of Zn and S voids are used as catalysts. The lowest S/Zn sample, ZnS0.67 and the highest S/Zn sample, ZnS3, show superior photocatalytic activity