Magnetic and fluorescent nanoparticles are widely studied in biomedical research such as drug delivery, imaging, etc. Hybrid nanoparticles combining both magnetic and fluorescent properties are particularly interesting. In this manuscript, we report a recent study on Fe3O4-Au hybrid nanoparticles displaying fluorescence. Fe3O4-Au hybrid nanoparticles were synthesized via solution phase chemical reaction in inert N2 atmosphere. The synthesized hybrid nanoparticles were characterized by UV-Vis-NIR spectroscopy and fluorescence spectroscopy, XRD, TEM, etc. The optimal synthesis condition yields stable, uniform hybrid nanoparticles without impurities. The correlation between fluorescent life- time and sizes, compositions, shapes of hybrid nanoparticles was discussed. Biomedical applications of synthesized hybrid nanoparticles, utilizing their fluorescent and magnetic properties, are still undergoing.

Fluoride levels in drinking water exceeding 1.5 mg/L especially underground water can be detrimental to health. Various defluoridation technologies exist such as reverse osmosis, adsorption and ion exchange. However, adsorption has been preferred over the other due to its low cost and ease of operation. In this study, a novel adsorbent nanomaterial was prepared to remove fluoride from drinking water. The influence of different parameters such as pH, contact time, co-existing ions and dosage were investigated in order to understand the sorption behaviour of the adsorbent under varying conditions. The adsorption process best fitted with the Langmuir model with a maximum adsorption capacity of 62.5 mg/g. The adsorbent can be used under normal water pH=7. Anions and cations had no influence on the sorption capacity except for chlorides, carbonates and bicarbonates. The adsorbent reduced fluoride concentration from 10 ppm to approximately 1.5 ppm per 50 mg nanocomposite loading as recommended by World Health Organization. The synthesized nanocomposite can be used for defluoridation of water with high fluoride concentrations beyond recommended limit.

Graphene reinforced natural rubber composites are developed to study the improvement in mechanical and tribological properties of natural rubber by the introduction of graphene as reinforcement. Constant strain minimization method has been applied to calculate Young’s and shear modulus of developed structures. A three-layer model containing Fe (Iron) atoms at the top and bottom and polymer matrices in the middle has been constructed to calculate the tribological properties. A shear loading is applied to the top iron nanorod by sliding it to the surface of the polymer matrices for 600 ps with a velocity of 0.01 nm/ps. The results show the increase of 185% in Young’s modulus, 32% in shear modulus and 48% in hardness by reinforcing natural rubber with single-layer graphene oxide sheet, respectively. Also, reduction of 28% and 36% in the friction coefficient and abrasion rate obtained by the introduction of graphene oxide sheet in natural rubber matrix. Also, interaction energy between graphene and natural rubber, the angle, bond and kinetic energy of the polymer and composites has been calculated and discussed.

Although Pb-based perovskite solar cells already achieve power conversion efficiencies (PCE) beyond 20 %, the use of toxic Pb is causing considerable environmental concern. As a consequence, a variety of alternative cations have been investigated to replace Pb2+ in the perovskite structure. Methylammonium bismuth iodide (MA3Bi2I9, MBI) has shown promising results for environmentally benign and chemically stable devices. While the PCE of MBI-based solar cells are still comparably low, structural improvements have been made by using chemical vapor deposition (CVD). CVD allows for the well-controlled formation of coherent and dense MBI layers in contrast to solution-processing. In this work, CVD as a possible MBI fabrication method for efficient and size-scalable solar cells is discussed. The precursors MA iodide (MAI) and Bi iodide (BiI3) are deposited in an alternating deposition process forming the desired MBI perovskite on the heated substrate. Substrate temperatures as well as deposition times of each precursor are varied with the aim of forming coherent and dense MBI layers. Optimized films are further processed to solar cell prototypes and compared with solution-processed reference devices. The results reveal that CVD possesses great potential to enable the manufacture of MBI photovoltaic (PV) devices processed in a solvent-free environment.

A kinetic model for ECM decellularization with Trypsin and Deoxycholic Acid as reactants in a batch system has been developed. The decellularization mechanism has been analysed by solving a series of ordinary differential equations relating heterogeneous reaction kinetics at the solid/liquid interface to mass transfer of reactant and products. In order to remove the Deoxyribonucleic acid (DNA) of porcine, special emphasis has been given to the surface area for regulating the depth and amount of the penetration of the reagent, the numerical analysis thereof, and the corresponding experiment were carried out. The effect of chemical reaction order, rate constants and mass transfer coefficients on the overall decellularization rate has been analysed and discussed.

In this work, a very high, locally applied electric field was used to induce whisker nucleation on an Sn film. The field was generated by using a conductive AFM tip and applying a voltage bias between the sample and the conductive cantilever. The tip-sample separation distance was thus controllable, and any dielectric breakdown could be avoided. At locations where the AFM tip was positioned for an extended period, minuscule whiskers were observed, whose growth direction matched vertical orientation of the field.

We report the investigation on the properties of a novel Te precursor (i-C3H7)2Te and its effectiveness in fabricating MoTe2. The vapor pressure of the precursor was obtained by measuring the pressure as a function of its temperature in a sealed chamber. As a result it showed a high vapor pressure of 552.1 Pa at room temperature. The decomposition of the precursor was also investigated using DFT calculation. It was shown that the most likely reaction during the course of the decomposition of (i-C3H7)2Te is (i-C3H7)2Te → H2Te + 2 C3H7. The effectiveness of the precursor on the fabrication of MoTe2 was also investigated. Sputter-deposited MoO3 was tellurized in a quartz-tube furnace at the temperature up to 440°C. The resulting film showed that the 80% of the original MoO3 was tellurized to form MoTe2. It was also shown that further optimization of tellurization is required in order to prevent formation of metal Mo and elemental Te.

The role of oxide nanoparticles in cavity formation of a nano-oxide-dispersed ferritic steel subjected to (Fe + He) dual-ion and (Fe + He + H) triple-ion irradiations has been studied using transmission electron microscopy to elucidate the synergistic effects of helium and hydrogen on radiation tolerance of nano-oxide-dispersed ferritic steel for fusion energy systems. The effect of oxide nanoparticles on suppressing radiation-induced void swelling is clearly revealed from the observation of preferred trapping of helium bubbles at oxide nanoparticles, which results in a unimodal distribution of cavities in the (Fe + He) dual-ion irradiated specimen. An adverse effect of hydrogen implantation, however, is revealed from the observation of a bimodal distribution of cavities with large and facetted voids in association with the formation of HFe5O8-based hydroxide in local regions of the (Fe + He + H) triple-ion irradiated specimen.

This work further advances the micromagnetic stimulation (μMS) technology, which has shown the capability of stimulating the nervous system using magnetic induction in a focal region of tissue by discharging a time-varying current through a sub-millimeter size coil. However, μMS was originally based on commercial off the shelf (COTS) inductors, which are designed to maximize efficiency and minimize its losses albeit shielding off the magnetic field from reaching the neural tissue. In this work, we study and fabricate microscale coil structures for next-generation μMS devices. The coil was designed to optimize the flux injected into the tissue by using a planar square spiral coil geometry, which was previously shown to be optimal for neuronal stimulation. The results of the electromagnetic Finite Elements Method (FEM) simulations of the proposed μMS device show that even though the spiral has a fully symmetric design, it nonetheless exhibits an asymmetry in the induced electric field in the tissue that can potentially be used for activating neurons with a specific axonal orientation. Such devices could become the brain and heart stimulators of the future with their contactless ability to deliver the neuronal stimulation needed for therapeutic efficacy in patients in need of implantable cardioverter-defibrillators or pace-makers, or patients with Parkinson’s disease, epilepsy.

We report on the results of coherent X-ray diffraction imaging (CXDI) and ptychography measurements of two individual core-shell-shell GaAs/(In,Ga)As/GaAs nanowires (NWs) grown by molecular beam epitaxy (MBE) on patterned Si(111) substrate. CXDI at the axial GaAs 111 Bragg reflection was applied at different positions along the NW axis in order to characterize the NWs in terms of structural homogeneity along the radial directions. At each positon 3D reciprocal space maps have been recoded and inverted using phase retrieval algorithms. The CXDI were complemented by 2D ptychography measurements at GaAs 111 Bragg reflection probing the same NWs with respect to their structural homogeneity. Both methods provide structural homogeneity for NW1 and NW2 except at the bottom part of the NWs. In case of NW2 CXDI and ptychography show changes in the structure of the top part of the NW indicated by 60° rotation of the indicated three-fold rotational symmetry in the observed diffraction patterns and changes in the strain field reconstructed from ptychography.

Extensive work has been done on the modification of multi-walled carbon nanotubes (MWCNTs) to improve their characteristics. Here, polystyrene (PS) was adsorbed on the surface of MWCNTs by dispersion process, using toluene as medium. PS modified MWCNTs (PS-MWCNTs) have been dispersed in polymethylmethacrylate (PMMA) matrix to prepare composite, PS-MWCNTs/PMMA. It is expected that PS adsorbed at the surface of the MWCNTs will help in improving the interaction between MWCNTs and PMMA which results uniform and homogeneous dispersion of the former in later. Thus, synthesized composites were characterized by UV-Vis and FTIR spectroscopy to monitor the functionality of developed product. Electrical parameters including conductivity and dielectric properties were measured with the help of LCR meter. Electrical characters of the composites were explored by investigating the effect of contents of PS-MWCNTs on conductivity and dielectric properties. Percolation behaviour was examined and calculated value of percolation threshold was 0.1wt%.

The apparent diffusion coefficients of La, Nd, Eu, Dy, Er, and Lu in compacted bentonites were investigated at various bicarbonate concentrations. The apparent diffusion coefficients of these lanthanides tended to decrease with increasing dry density. At bicarbonate concentrations below 0.25 M, lanthanum had the largest diffusion coefficient (ca. 10-13 m2/s) at 1.0 Mg/m3, and the diffusion coefficient decreased with increasing atomic number. On the other hand, at bicarbonate concentrations above 0.25 M, lutetium had the largest diffusion coefficient, and the diffusion coefficient decreased with decreasing atomic number. In particular, lanthanum and neodymium had diffusion coefficients below 10-14 m2/s, even at 1.0 Mg/m3. The diffusion coefficient of europium was around 10-13 m2/s at 1.0 Mg/m3 and was influenced less by the bicarbonate concentration. The diffusion coefficient of lutetium increased from 2 × 10-14 to 10-12 m2/s as the bicarbonate concentration was increased to 1.0 M. The concentration of carbonate ion in the pore water of bentonite is estimated to be much lower than that in solutions in contact with bentonite from the viewpoints of solubility and chemical species of lanthanides.

Graphene and graphene oxide are being investigated for use in drug delivery systems, bioimaging, and antimicrobial applications. However, their effects, if any, on healthy cells need to be established before they can be deemed safe for therapeutic use. This research tested whether graphene oxide (GO) and/or partially reduced graphene oxide (pRGO) exhibit antimicrobial properties on Staphylococcus aureus; and also examined the growth and proliferation of dermal fibroblasts and keratinocytes in media modified with graphene oxide or partially reduced graphene oxide. Staphylococcus aureus was able to proliferate in both GO and pRGO- modified growth media as well as on gelatin made with GO and pRGO solutions. Both GO and pRGO increased dermal fibroblast doubling time and displayed lower cell counts compared to the control, with pRGO exerting a more pronounced effect than GO. After 4 days of keratinocyte incubation, GO and pRGO showed cell counts 75-80% less than the control. Cell counts of test samples dropped even lower by day 5 while the control cell count increased, suggesting that more investigation into the properties as well as the safety of graphene and its derivatives needs to be done before it is implemented for medical applications.

In this work, we study the hard-magnetic properties and its influence on the microstructure of MnBi-based glass-coated microwires obtained by Taylor-Ulitovsky process, as well as their magnetic and thermal dependence in the range of 200 K-360 K. We obtained glass-coated microwires pieces trough of the Taylor-Ulitovsky process. Glass-coated microwires exhibited the formation of Low-Temperature Intermetallic Phase (LTIP)-MnBi, as confirmed by scanning electron microscopy (SEM). Energy Dispersive Spectroscopy (EDS) elemental chemical composition analysis showed LTIP regions interspersed within Bi- and Mn-rich areas. Magnetic properties were determined by vibrating sample magnetometry (VSM), for which a considerable intrinsic coercivity field (iHc) up to 6000 Oe at 360 K, together with a saturation magnetization (Ms) of 57.49 emu/cm3. Therefore, this combination of properties renders LTIP is a promising precursor with potential for applications at high temperatures.

This work decribes the enhancement of the electrical figures of merit of an Electrolyte Gated Thin-Film Transistor (EG-TFT) comprising a nanocomposite of n-type tungsten disulfide (WS2) nanotubes (NTs) dispersed in a regio-regular p-type poly(3-hexylthiophene-2,5-diyl) (P3HT) polymeric matrix. P3HT/WS2 nanocomposites loaded with different concentrations of NTs, serving as EG-TFTs electronic channel materials have been studied and the formulation has been optimized. The resulting EG-TFTs figures of merit (field-effect mobility, threshold voltage and on-off ratio) are compared with those of the device comprising a bare P3HT semiconducting layer. The optimized P3HT/WS2 nanocomposite, comprising a 60% by weight of NTs, results in an improvement of all the elicited figures of merit with a striking ten-fold increase in the field-effect mobility and the on/off ratio along with a sizable enhancement of the in-water operational stability of the device.

Silver nanoparticle based microelectrodes embedded between layers of hydrogel material were successfully fabricated. 3D bioprinting is employed to print the entire bioelectronics platform comprising of conducting silver ink and Gelatin methacryloyl (GelMA) hydrogel. The additive manufacturing technique of bioprinting gives design freedom for the circuit, saves material and shortens the time to fabricate the bioelectronics platform. The silver platform shows excellent electrical conductivity, structural flexibility and stability in wet environment. It is tested for biocompatibility using C2C12 murine myoblasts cell line. The work demonstrates the potential of the fabricated platform for the realization of practical bioelectronic devices.

The cadmium telluride (CdTe) photovoltaic (PV) comprise an efficient and cost-effective technology for harvesting solar energy. However, device efficiency remains limited in part by low-open circuit voltage (VOC) and fill factor (FF) due to inefficient transport of photo-generated charge carriers. Given the deep valence band of CdTe, the use of copper/gold (Cu/Au) as a back contact serves primarily to narrow the width of the inherent Schottky junction evident in CdTe solar cells (in our laboratory, Cu/Au has been used as a standard back contact). For efficient transport of carriers to and into the back contact, a hole transport layer (HTL) is desired with valence band edge comparable to that of CdTe (∼ -5.9 eV). Here, we report solution-processed nanocrystal (NCs) based thin films as HTLs in CdTe solar cells. The earth abundant materials we discuss include iron pyrite (FeS2), nickel-alloyed iron pyrite (NixFe1-xS2), zinc copper sulfide (ZnxCu1-xS) nanocomposites, and perovskite-based films. The FeS2 and NixFe1-xS2 NCs are synthesized by a hot-injection route, and thin films are fabricated by drop-casting, and spin-coating techniques using colloidal NCs. ZnxCu1-xS thin films are fabricated by chemical bath deposition. These NC-based thin films are applied and studied as the HTLs in CdTe devices. On using these materials, the device performance can be increased up to 10% compared to the standard Cu/Au back contact. Here, we discuss the benefits, challenges, and opportunities for these back contact materials in CdTe photovoltaics.

Slow cooling of phosphate melt at liquid nuclear waste solidification yields glass-crystalline material. Partial crystallization during melt solidification results in elemental partitioning among crystalline phase and glass: Al, Cr, Fe are concentrated in the crystalline phosphate phase while Ca, Ni, La, U enter predominantly in the residual glass. Glass dissolution rate and leach rate of La and U as rare earth and actinide surrogates depends strongly on the glass composition, for example reduction of Al2O3 content in the glass to ∼10-12 wt.% increases leachability by three orders of magnitude as compared to the glass with specified composition (∼18-22 wt.% Al2O3).

Mesoporous silicas were synthesized via a surfactant-templated sol-gel route using castor oil as the templating agent under acidic medium. The resulting silicas were subsequently amine functionalized with 3-aminopropyltriethoxysilane (NH2-MTS), [3-(2-aminoethylamino)-propyl]trimethoxysilane (NN-MTS), and [3-(diethylamino)propyl]trimethoxysilane(DN-MTS) to introduce surface basicity. Surface physicochemical properties were characterized by field emission gun scanning electron microscopy (FEGSEM), nitrogen porosimetry, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and diffuse reflectance infrared fourier transform spectroscopy (DRIFTS). As-synthesised materials exhibit type IV adsorption-desorption isotherms characteristic of mesoporous structures. Clusters of spherical shaped materials were observed by FEGSEM, suggesting growth of silica occurs within colloidal dispersions. High-resolution N 1s XP spectra and DRIFT spectra confirmed the presence of amine groups in the organo-amine functionalised mesoporous silicas. The amine functionalised mesoporous silicas were active for the transesterification of tributyrin with methanol, with conversion found to increase from NH2-MTS< NN-MTS< DN-MTS.

This is a cross institution project involving four Institutes of Technology in Ireland. The objective of this project is to assess the use of technology to enhance the assessment of laboratory sessions in Science and Health. In science, health and engineering, the laboratory sessions are at the core of the learning process for skill development. These laboratory sessions focus on the skills acquisition. The Irish Institute of Technology sector, in particular, develops these skills and considers them essential for ‘professionally ready’ graduates. In terms of student progression and retention, the assessment structure has been identified as having a significant impact on student engagement.

The Technology Enhanced Assessment Methods (TEAM) project led by Dundalk Institute of Technology and partnering with Institute of Technology Sligo, Athlone Institute of Technology and Institute of Technology Carlow is exploring the potential offered by digital technologies to address these concerns. It aims to develop a framework for applying the principles of effective assessment and feedback to practical assessment. The TEAM project also aims to facilitate dialogue among stakeholders about what it is we want student to learn in laboratory sessions and how our assessment can facilitate this. A peer network of discipline-specific academics and students in the Science and Health field has been established across all four Institutes. As the network focuses on authentic skills assessment in all core modules, including physics and chemistry, the best practice from this project will inform future assessment procedures across laboratory sessions and may be considered for application within a Science and Materials Engineering context.

Assessing the skills acquired in this environment takes many forms. Using student and stakeholder feedback along with an extensive literature review of the area, the team identified key technologies that cut across science and health disciplines, with the potential to influence and enable the learning process. The emphasis was on developing a powerful learning environment approach to enable students to deepen their learning through engagement with the process. The areas identified are: (i) Pre-practical preparation (videos and quizzes), (ii) Electronic laboratory notebooks and ePortfolios, (iii) Digital Feedback technologies and (iv) Rubrics).

This paper describes the student experience and perceptions of the adoption of digital technology in science practical assessments. It also describes the process involved in setting up the pilot structure and it presents the initial results from the student survey.