An analysis of targeted properties of materials used for preservation and storage of heritage collections

The aim of this study was to stress the importance of investigating the prop- erties of preservation enclosure materials in order to identify the ones that are able to protect their contents more efficiently. Since not all information on materials is covered by international standards and technical specifica- tions, nine paper-based materials used for making preservation enclosures (file folders, passepartouts, boxes etc.) were investigated. A selective analysis of the materials' properties was carried out to determine smoothness, water absorptiveness, water wettability, water vapor permeability, tensile strength, folding endurance, bursting strength, puncture strength, as well as loss of bursting strength caused by dry heat and 100% RH. Results obtained from measuring smoothness, water absorptiveness, water wettability and water vapor transmission rate indicate that a material outside of ISO 16245:2009 grammage requirements for making file covers can exhibit more desirable properties than the one that meets multiple standards for storage and preservation. Additionally, results showed that bursting strength of enclosure materials was significantly affected by both extreme microclimate condi- tions. However, 100% RH had affected bursting strength of the investigated materials more than dry heat. The presented procedure proved to be a useful indicator of materials’ properties within the context of heritage collections preservation and storage.

Exploring the Limits of the Rapid-Charging Performance of Graphite as the Anode in Lithium-Ion Batteries

Graphite is, in principle, applicable as a high-power anode in lithium-ion batteries (LIBs) given its high intralayer lithium diffusivity at room temperature. However, such cells are known to exhibit poor capacity retention and/or undergo irreversible side reactions including lithium plating when charged at current rates above ~2C (~740 mA g-1). To explore the inherent materials properties that limit graphite anodes in rapid-charge applications, a series of full-cells consisting of graphite as the anode and a standard Li[Ni0.8Mn0.1Co0.1]O2 (NMC811) cathode was investigated. Instead of a conventional cathode-limited cell design, an anode-limited approach was used in this work to ensure that the overall cell capacity is only determined by the graphite electrode of interest. The optimized N:P capacity ratio was determined as N/P = 0.67, enabling stable cycling across a wide range of charging rates (4-20C) without inhibition by the NMC811 cathode. The results show that unmodified, highly crystalline graphite can be an excellent anode for rapid-charge applications at up to 8C, even with a standard electrolyte and NMC811 cathode and in cells with 1.0 mAh cm-2 loadings. As a rule, capacity and specific energy are inversely proportional to crystallite size at high rates; performance can likely be improved by electrolyte/cathode tuning.

An Analytical Approach for Computing the Coefficient of Refrigeration Performance in Giant Inverse Magnetocaloric Materials

An analytical approach for computing the coefficient of refrigeration performance (CRP) was described for materials that exhibited a giant inverse magnetocaloric effect (MCE), and their governing thermodynamics were reviewed. The approach defines the magnetic work input using thermodynamic relationships rather than isothermal magnetization data discretized from the literature. The CRP was computed for only cyclically reversible temperature and entropy changes in materials that exhibited thermal hysteresis by placing a limit on their operating temperature in a thermodynamic cycle. The analytical CRP serves to link meaningful material properties in first-order MCE refrigerants to their potential work and efficiency and can be employed as a metric to compare the behaviors of dissimilar alloy compositions or for materials design. We found that an optimum in the CRP may exist that depends on the applied field level and Clausius–Clapeyron (CC) slope. Moreover, through a large literature review of NiMn-based materials, we note that NiMn(In/Sn) alloys offer the most promising materials properties for applications within the bounds of the developed framework.

Controlling magnetic-semiconductor properties of the Si- and Al-doped blue phosphorene monolayer

Doping has been widely employed as an efficient method to diversify the materials properties. In this work, the structural, magnetic, and electronic properties of pristine, aluminum(Al)-, and silicon(Si)-doped blue phosphorene monolayer are investigated using first-principles calculations. Pristine monolayer is a non-magnetic wide gap semiconductor with a band gap of 1.81 eV. The 1Si-doped system is a ferromagnetic semiconductor. However, the magnetism is turned off when increasing the dopant composition with small Si-Si distance. Further separating the dopants recovers step by step the magnetic properties, and an antiferromagnetic(AFM)-ferromagnetic(FM) state transition will take place at large dopants separation. In contrast, Al doping retains the non-magnetic semiconductor behavior of blue phosphorene. However, significant energy gap reduction is achieved, where this parameter exhibits a strong dependence on the dopant concentration and doping configuration. Such control may also induce the indirect-direct gap transition. Our results introduce prospective two-dimensional (2D) materials for applications in spintronic and optoelectronic nano devices, which can be realized and stabilized in experiments as suggested by the calculated formation and cohesive energies.

Data-Driven Prediction of Grain Boundary Segregation and Disordering in High-Entropy Alloys in a 5D Space

Grain boundaries (GBs) can critically influence the microstructural evolution and various materials properties. However, a fundamental understanding of GBs in high-entropy alloys (HEAs) is lacking because of the complex couplings...

Diels–Alder Cycloaddition with CO, CO2, SO2, or N2 Extrusion: A Powerful Tool for Material Chemistry

Phenyl, naphthyl, polyarylphenyl, coronene, and other aromatic and polyaromatic moieties primarily influence the final materials’ properties. One of the synthetic tools used to implement (hetero)aromatic moieties into final structures is Diels–Alder cycloaddition (DAC), typically combined with Scholl dehydrocondensation. Substituted 2-pyranones, 1,1-dioxothiophenes, and, especially, 1,3-cyclopentadienones are valuable substrates for [4 + 2] cycloaddition, leading to multisubstituted derivatives of benzene, naphthalene, and other aromatics. Cycloadditions of dienes can be carried out with extrusion of carbon dioxide, carbon oxide, or sulphur dioxide. When pyranones, dioxothiophenes, or cyclopentadienones and DA cycloaddition are aided with acetylenes including masked ones, conjugated or isolated diynes, or polyynes and arynes, aromatic systems are obtained. This review covers the development and the current state of knowledge regarding thermal DA cycloaddition of dienes mentioned above and dienophiles leading to (hetero)aromatics via CO, CO2, or SO2 extrusion. Particular attention was paid to the role that introduced aromatic moieties play in designing molecular structures with expected properties. Undoubtedly, the DAC variants described in this review, combined with other modern synthetic tools, constitute a convenient and efficient way of obtaining functionalized nanomaterials, continually showing the potential to impact materials sciences and new technologies in the nearest future.

Measurement of Dielectric and Magnetic Constants of Ferrofluid-Doped Sol-Gels by a Resonant Cavity Method

Materials with specific electromagnetic properties are increasingly used for the realization of passive components. Therefore, electromagnetic characterization is a priority to know these materials properties. This study focuses on the electromagnetic characterization of 10 nm maghemite ferrofluid doped sol-gel using a resonant cavity method. We deposited the sol-gel by dipping/removal on an alumina substrate in order to make measurements on the cavity to determine the complex permittivity and permeability. Two studies were carried out; the first consisted in varying the doped sol-gel thickness of layers of the same concentration in the realization of samples; and the second consisted in varying the volume concentration of ferrofluid according to the matrix dimensions. The first study showed that the dielectric constants do not vary with the thickness of the magnetic sol-gel layers. In the second study, measurements also showed that the gyromagnetic resonance is the same for all samples regardless of the ferrofluid volume concentration.

Structural properties of TiO2-SnO2 thin films prepared by new pyrolysis solid-phase method

Nanoscale TiO2-SnO2 films with the Ti:Sn ratio 1:99, 3:97 and 5:95 mol%, respectively, were obtained by solid-phase low-temperature pyrolysis method. The synthesized materials were studied by X-ray phase analysis and scanning electron microscopy (SEM) analysis. Regardless of the modified agents’ concentration, the structure of cassiterite was observed for all synthesized materials. When studying the effect of synthesis parameters on the materials properties, it was shown that both an increase in the Ti4+ concentration and in the calcination temperature leads to an increase in the particle size.