Deinking of recycled office (MOW) paper was carried out by using a flotation column and adding separately sodium hydroxide, and the enzyme Cellulase Thricodema Sp., as defibrillators.

The de-inked cellulose fibers were characterized according to the standards of the paper industry, to compare the efficiency of the deinking of each chemical reagent used to hydrolyze the fibers and defibrillate them.

The computational simulation of the molecular coupling between the enzyme and cellulose was performed, to establish the enzyme-cellulose molecular complex and then to identify the principal amino-acids of endo-β-1,4-D-glucanase in this molecular link, which are responsible for the hydrolysis of the cellulose.

Experimental results show the feasibility to replace sodium hydroxide with the enzyme Cellulase Thricodema Sp., by obtaining deinked cellulose with similar optical and physical properties.

The use of the enzyme instead of sodium hydroxide avoids the contamination of the residual water; in addition to that, the column is operated more easily, taking into consideration that the pH of the system goes from alkaline to neutral.

The three generically accepted stages of glass corrosion are reviewed with focus on final stage termed alteration rate renewal (or resumption) stage when the glass may re-start corroding with the rate similar to that at the initial stage. It is emphasized that physical state and physical changes that occur in the near-surface layers can readily lead to an effective increase of leaching rate which is similar to alteration rate renewals. Experimental data on long-term (during few decades) corrosion of radioactive borosilicate glass K26 designed to immobilize high-sodium operational NPP radioactive waste evidence on resumption-like effects of radionuclides (137,134Cs) leaching. The cause of that was however related not to chemical changes in the leaching environment but rather to physical state of glass surface due to formation of small cracks and new pristine glass areas in contact with water.

Two-dimensional (2D) layered materials hosting dislocations have attracted considerable research attention in recent years. In particular, screw dislocations can result in a spiral topology and an interlayer twist in the layered materials, significantly impacting the stacking order and symmetry of the layers. Moreover, the dislocations with large strain and heavily distorted atomic registry can result in a local modification of the structures around the dislocation. The dislocations thus provide a useful route to engineering optical, electrical, thermal, mechanical and catalytic properties of the 2D layered materials, which show great potential to bring new functionalities. This article presents a comprehensive review of the experimental and theoretical progress on the growth and properties of the dislocated 2D layered materials. It also offers an outlook on the future works in this promising research field.

The transport and deposition of uranium under hydrothermal conditions in the Earth’s crust has been a subject of ongoing study but is yet to be completely understood. In addition, there is little known about the fate of nuclear waste, consisting of uranium from spent fuel and other radioactive materials, upon storage in repositories or in nuclear reactor facilities. Because the nuclear waste often comes in contact with aqueous fluids in storage environments, studies of uranyl complexation with chloride and other ligands in aqueous media, to high temperature and pressure conditions, are needed. The primary purpose of this study was to investigate the speciation of aqueous uranyl (VI) chloride complexes, in solutions having a 0.05 M uranyl concentration and [Cl] concentrations ranging from 0.2 M to 6 M, under hydrothermal conditions. The aqueous uranyl chloride complexes in the samples were studied using Raman spectroscopy and the hydrothermal diamond anvil cell (HDAC), at temperatures up to 500 °C and pressures up to ~ 0.5 GPa. The uranyl bond stretching band feature occurring in the ~810 to 870 cm-1 region was fitted using the Voigt peak shape to determine the speciation of the equilibrium uranyl chloride complexes present in the samples. As expected, the n integer value of the UO2Cln+2-n complex species increases with the increase in temperature and chloride concentration, generally trending toward charge neutrality at high temperatures.

P-type NiO powders with an average crystallite size of 16 nm as shown by x-ray diffraction analysis were produced via biosynthesis using cactus plant extract. SEM showed that the NiO powders consisted of particles with sizes in the 20-35 nm range. A cyclic voltammetric study of the NiO nanopowders showed a quasi-reversible redox processes with the NiO powder showing potential for pseudo capacitance. Through these findings the use of natural Cactus extracts is hereby shown to be a cost-effective and environmentally friendly alternative for preparing Nickel oxide nanosized powders that can be of use in a variety of energy storage applications.

This work reports on the use of diatomaceous earth (DE) waste and organic binder derived from Corchorus olitorius, locally known as “Mrenda” in the design of an efficient water filtration membranes. Charcoal powder was incorporated to enhance the porosity of the membrane. The firing was done at temperatures varying from 700.0 °C to 1150.0 °C. The DE waste samples comprised 79.0% silica (by mass) and 11.0% total flux content compared to porter’s clay that had 50.0% silica, 28.8% AL2O3 and 7.0% total flux content. On the other hand, the “Mrenda” binder contained 6.5% total organic matter. The use of the plant-derived binder enhanced the mechanical strength of the greenware by 52.7% and the fired membranes by 152.2%. The fabricated DE waste-based membranes were 15.0% stronger than clay-based ceramic membranes prepared under similar conditions. A sintering temperature of 900.0 °C was optimal in producing porous membranes for filtering of 4.1 liters of water per hour. The pore diameter of the membranes fabricated from DE waste only ranged between 2.0 nm – 99.0 nm. On micro-organisms filtering efficacy, the DE waste-based membranes and those fabricated with 5.0% charcoal were 99.9% and 88.4% effective in the removal of E. coli and Rotavirus respectively.

Herein we describe a technique for preparing samples from cycled Li-ion batteries with minimal contact with atmospheric water for examination by TEM and to provide the results of an analysis of the SEI in Li-ion cells. The electrode samples were prepared in a glove box by manipulation with a diamond tipped pen to carefully dislodge particles directly onto the TEM sample holder. Electrodes were extracted from Li-ion cells that contained a cathode of high capacity, manganese rich NCM (HCMR-NCM). Nanometer-sized MnF2 crystal particles embed themselves in the SEI layer of the anodes as observed and confirmed by HRTEM lattice image analysis and EELS. Cross-sections of the SEI layer reveal that the thickness of the SEI and propensity for MnF2 crystal deposition is non-uniform.

We have successfully synthesized GexSe1-x (x = 0.225) glass samples and incorporated commercially produced (Protein Mods) carbon nanotubes (CNTs) into the glass samples. We investigated the glass transition temperature (Tg) using modulated differential scanning calorimetry (MDSC). CNTs, being a very hygroscopic material as well as oxygen absorbing material, needed to be cleaned under vacuum with the hot water-bath to get rid of contaminants. We used contaminant-free CNTs for our study. The same cleaning process was used to prepare GexSe1-x (x = 0.225) glass samples with and without CNTs. The base GexSe1-x (x = 0.225) glass sample has a Tg of 220°C. The Tg was found to be independent of starting materials (germanium and selenium) from different sources as well as hot water-bath temperature. The Tg was found to be lower when 5% CNT's by mass was added to the base GexSe1-x (x = 0.225) glass sample. For 10% incorporation, the Tg was found to increase from that of 5% and it was found to decrease from that of 10% when 15% CNTs was added to the base glass sample. We also found that the Tg for GexSe1-x (x = 0.225) glass samples with the incorporation of 5% not-cleaned CNTs was 10oC higher, indicating the sensitivity of Tg on contaminants. Further, it was found that the variation of Tg with the incorporation of bulk carbon into the GexSe1-x (x = 0.225) glass samples was inconsistent compared to the contaminant-free CNTs incorporation.

Recruitment of mesenchymal stem cells (MSCs) to damaged tissue is a crucial step to modulate tissue regeneration. Here, the migration of human adipose-derived stem cells (hADSCs) responding to thermal and mechanical stimuli was investigated using programmable shape-memory polymer actuator (SMPA) sheets. Changing the temperature repetitively between 10 and 37 °C, the SMPA sheets are capable of reversibly changing between two different pre-defined shapes like an artificial muscle. Compared to non-actuating sheets, the cells cultured on the programmed actuating sheets presented a higher migration velocity (0.32 ± 0.1 vs. 0.57 ± 0.2 μm/min). These results could motivate the next scientific steps, for example, to investigate the MSCs pre-loaded in organoids towards their migration potential.

The need to achieve a uniform distribution of concentrated solar flux in the photovoltaic, thermal or any other receivers is a common problem; therefore, the optical characterization of the concentration system is necessary to determinate the physical characteristics of the receptors. In this work, a parabolic dish concentrator of 1.65x1.65 m2, developed by research from the University of Arizona, is optically characterized under normal operating conditions, also known as environmental conditions that refer to non-controlled conditions as solar radiation, environmental temperature and wind velocity that could affect slightly, by thermal and mechanical efforts, the distribution profiles of the concentrated solar radiation. The set used for the evaluation consisted of the parabolic mirror and Chilled Lambertian Flat Surface installed in the focal point on the optical axis of the mirror. The evaluation was divided into two parts: a theoretical part that consist on using ray tracing simulation and an experimental part that corresponds to image analysis. The used methodology in this work has been stablish in many researches, so this is a reliable method. The global optical error was 2.3 mrad under normal operating conditions.

Using water as an example, it is shown that monitoring the change in the loss tangent is a high sensitive method that allows determining the activation energy of relaxation processes in nanostructured water with high accuracy. The use of sensors, the electrodes of which are not in direct contact with the liquid under study is shown to be reasonable. The conditions for obtaining reliable information on the properties of water and its solutions are also justified, namely: measurements should be carried out using pulse methods for several seconds, and then measurements should be stopped to avoid contamination of the solutions studied by electrolysis products. The method of monitoring the magnitude of the loss tangent at fixed frequencies allows the acidity of solutions (pH value) to be controlled at the same time without using specialized instruments for acidity studying.

Propagating inhomogeneous electromagnetic waves called surface plasmon polaritons (SPPs) can be excited by free-space beams on corrugated conducting surfaces at resonance angles determined by corrugation period, permittivity, and optical frequency. SPPs are coupled to and co-propagate with surface charge displacements. Complete electrical isolation of individual conducting corrugations prevents the charge displacement necessary to sustain an SPP, such that excitation resonances of traveling SPPs are absent. However, SPPs can be excited via electric induction if a smooth conducting surface exists below and nearby the isolated conducting corrugations. The dependence of SPP excitation resonances on that separation is experimentally investigated here at long-wave infrared wavelengths. We find that excitation resonances for traveling SPPs broaden and disappear as the dielectric’s physical thickness is increased beyond ~1% of the free-space wavelength. The resonance line width increases with refractive index and optical thickness of the dielectric.

Low-cost, light-weight, low-power, large-format, room-temperature, mid-wave infrared (MWIR) detectors are needed for reduced-scale aircraft. An opportunity, suggested by direct-read X-radiography systems, is the use of thin film transistor (TFT) array as read-out integrated circuit (ROIC) for low-cost sensors deposited directly and unpatterned onto this ROIC. TFTs have already been thoroughly optimized for power, weight, large-format, and cost by the flat-panel-display industry. We present experimental investigation of aqueous-spray-deposited, mid-wave-IR, metal-chalcogenide heterojunction CdS/PbS photodiodes for this application. Measured responsivity, detectivity D*, and photoresponse spectra are reported.

Silver nanoparticles (Ag NPs) have unique optical, electrical, and thermal properties and are being incorporated into products that range from photovoltaics to biological and chemical sensors. The production of silver nanoparticles has been increasing worldwide in the nanotechnology industry due to the variety of applications and are very likely to reach aquatic ecosystems damaging them. Due to their small size and high surface area to volume ratio of NPs, they can strongly interact with life cells and cause damage to tested animals. Based on the mentioned previously, it is necessary to evaluate the silver nanoparticle nanotoxicity in aquatic ecosystems to prevent possible ingestion or transfer to humans. Also, the research will benefit aquatic systems due to less pollution around aquatic organisms. The objectives of this research included: i) production and characterization of stable silver nanoparticles in water, ii) characterizing the optical properties by UV-Vis spectroscopy and morphology by HR-TEM and; iii) evaluate the toxicity of silver nanoparticles in aquatic organisms, i.e Artemia salina. Results obtained evidenced that Ag NPs showed an intense absorption peak at 448 nm. This broad peak is due to the phenomenon called surface plasmon resonance (SPR) that is responsible for a variety of phenomena, including nanoscale optical focusing, negative refraction, and surface-enhanced Raman scattering. HR-TEM measurements evidenced the spherical form of the nanoparticles and its small size at around 12-20 nm. In addition, Electron Diffraction analyses suggested the composition of the nanoparticle, which contained only Ag0. The toxicity assays were evaluated using different concentrations of purified Ag NPs. During the cytotoxicity assay, it was demonstrated that Ag NPs were not toxic to Artemia salina after 24 and 48 hours of exposure. However, silver (as silver nitrate) evidenced high toxicity to Artemia salina at larval stage.

Ancient Roman concrete presents exceptional durability, low-carbon footprint, and interlocking minerals that add cohesion to the final composition. Understanding of the structural characteristics of these materials using X-ray tomography (XRT) is of paramount importance in the process of designing future materials with similar complex heterogeneous structures. We introduce Materials Data Science algorithms centered on image analysis of XRT that support inspection and quantification of microstructure from ancient Roman concrete samples. By using XRT imaging, we access properties of two concrete samples in terms of three different material phases as well as estimation of materials fraction, visualization of the porous network and density gradients. These samples present remarkable durability in comparison with the concrete using Portland cement and nonreactive aggregates. Internal structures and respective organization might be the key to construction durability as these samples come from ocean-submersed archeological findings dated from about two thousand years ago. These are preliminary results that highlight the advantages of using non-destructive 3D XRT combined with computer vision and machine learning methods for systematic characterization of complex and irreproducible materials such as archeological samples. One significant impact of this work is the ability to reduce the amount of data for several computations to be held at minimalistic computational infrastructure, near real-time, and potentially during beamtime while materials scientists are still at the imaging facilities.

This study reports on the effect of introducing TiO2 compact layer on the photovoltaic characteristics of TiO2/Nb2O5 composite dye sensitized solar cell. The compact layer was deposited by spray pyrolysis technique. It was observed that introduction of 60 nm thick compact layer improved the short circuit current density Jsc ,Open circuit voltage Voc, and efficiency of the cell from 4.9 mA/cm2 to 8.2 mA/cm2, 6.8×10-1 V to 7.2×10-1 V and 1.9 % to 3.4 % respectively compared to traditional cell prepared without compact layer. Electrochemical impedance spectroscopy confirmed an increase in recombination resistance from 5.5×101 Ω.cm2 for bare DSSC to 9.0×101 Ω.cm2 for DSSC with compact layer thereby improving electron lifetime of the cells from 2.5×10-4 s to 386.9×10-4 s.

While the use of iron oxide nanoparticles as magnetic resonance contrast agents for clinical imaging is established, they are more recently experiencing renewed interest as alternatives to gadolinium-based contrast agents. Ultra-small iron oxide nanoparticles have unique pharmacokinetics, metabolic and imaging properties. These properties have led to improved techniques for imaging a variety of vascular, oncologic and inflammatory conditions with iron oxide nanoparticles. Current research efforts are aimed at harnessing the characteristics of these nanoparticles to advance magnetic resonance imaging techniques and explore new therapeutic potentials. While there are some limitations to the use of iron oxide nanoparticles, including allergies to parenteral iron and iron storage disorders, the practicable applications for these agents will continue to expand. The purpose of this review is to provide a brief overview of the history and synthesis of iron oxide nanoparticles, their current applications in clinical imaging and their prospective clinical applications.

A novel series of copolymers were obtained from the copolymerization of 1-ethynylpyrene (EP) (known as pyrenylacetylene) and ethynylbenzene (EB) (named also phenylacetylene) with WCl6 as catalyst and toluene as solvent, using different monomer molar ratios EP/EB (80:20, 60:40, 50:50; 40:60, 20:80). The optical properties of the obtained copolymers Poly(EP-co-EB) were determined by absorption and fluorescence spectroscopy. Absorption spectra of the copolymers Poly(EP-co-EB) showed that copolymers containing phenylacetylene units possess a lower degree of conjugation than the homopolymer trans-poly(1-ethynylpyrene) (trans-PEP), since they showed a twisted conformation. These results were confirmed by emission spectroscopy showing the formation of excimers for those copolymers containing high pyrene content.

The Reaction Centers (RCs) proteins are membrane proteins representing the key component so flight energy transduction in photosynthetic organisms. Upon photon absorption, these photoenzymes produce a long lasting intra protein hole electron couples whose charges are separated by 3 nanometers. The dipoles formed within the RCs can be effectively employed as transducing cores of several biological-organic hybrid devices whose design can accomplish photocurrents generation or act as phototransistor. To widen the application of the RCs to as many substrate as possible one valuable strategy is the bioconjugation of the protein with specific molecules ad-hoc selected to improve enzymatic performance and/or integration in proper scaffolding. In the present manuscript, we investigate the changes of the isoelectric point of the RC from the carotenoidless strain of the photosynthetic bacterium Rhodobacter sphaeroides R26 by inducing “in silico” mutations to predict on the role of the aminoacids involved in the bioconjugation.

Ceria (CeO2) possesses a distinctive redox property due to a reversible conversion to its nonstoichiometric oxide and has been considered as a promising catalyst in the oxidative coupling of methane. Since a heterogeneously catalytic process usually takes place only on the surface of catalysts, it is reasonably expected that the performance of a catalyst, such as CeO2, highly relies on its size- and shape-dependent surface structure. We report our recent progress in achieving exclusive crystal facet-terminated CeO2 nanocrystals using a shape-controlled synthesis protocol in a one-pot colloidal system. We modified a two-phase solvothermal approach to fabricate cubic and truncated octahedral CeO2 nanocrystals with a size-control. During the two-phase solvothermal process, we propose that the Ce-precursors transfer from the aqueous layer to the interface of the organic phase, promoted by the capping ligands (as known as phase-transfer catalysts), for the oxidation and nucleation, and subsequently form CeO2 nanocrystals in the organic layer. As different capping ligands favor binding on diverse crystal facets, tuning the composition of the capping ligand with a precise control could generate nanocrystals that are dominated by a single type of facets with a relatively narrow size distribution.