Narrow Results

The paper studies the effect of temperature ($T$), ($T=300$, 3200, 4000, 5000, 6000, 7000K) at pressure $P=0$GPa; pressure ($P$), ($P=0$, 100, 200, 300, 350, 400GPa) at $T=7000$K and thermal annealing time ($t$), $t=47.8$ps (after 10⁵ steps) at $T=7000$K, $P=400$Gpa) on the structure of MgSiO₃ bulk 3000 atoms by Molecular Dynamics (MD) simulation using Born–Mayer (BM) pair interaction potential and periodic boundary conditions. The structural results are analyzed through the Radial Distribution Function (RDF), the Coordination Number (CN), the angle distribution, size ($l$), total energy of the system ($E_{\mathrm{\text{tot}}}$) and the bonding lengths. The results show that the temperature and pressure had influenced the structural properties of MgSiO₃ bulk and formation process geology of the Earth. In addition, the center of the Earth with $T=7000$K and $P=350$GPa has appearance and disappearance of the Si–Si, Si–O, O–O, Si–Mg, O–Mg, Mg–Mg bonds and SiO₄, SiO₅, SiO₆, MgO₃, MgO₄, MgO₅, MgO₆, MgO₇, MgO₈, MgO₉, MgO${}_{10}$, MgO${}_{11}$, MgO${}_{12}$ angle distributions. When increasing the depth of the Earth’s surface $(h)$ lead to size $(l)$ of MgSiO₃ decreases, total energy of the system ($E_{\mathrm{\text{tot}}}$) increases, position of first peak of Radial Distribution Function (RDF) is $(r)$, height of RDF is $g(r)$ varies greatly with $h$ from $h=0$km to $h=1820$km, gradually decreasing with $h$ from $h=2000$km to $h=3200$km and the smallest structural change with $h>3200$km that shows has influence affects on the geological formation of the Earth.

This paper studies the effect of atoms number $(N)$ of bulk Ag: $N=2916$ atoms (Ag${}_{2916}$), 4000 atoms (Ag${}_{4000}$), 5324 atoms (Ag${}_{5324})$, 6912 atoms (Ag${}_{6912})$ at temperature $T=300$K, 400K, 500K, 600K, 700K, 800K, 900K, 1000K on bulk Ag${}_{5324}$ and annealing time $t$ = 200 ps on the structure and phase transition of Ag bulk by Molecular Dynamics (MD) method with Sutton–Chen (SC) pair interaction potential, periodic boundary conditions. The structural results are analyzed through the Radial Distribution Function (RDF), the total energy of the system ($E_{tot})$, the size $(l)$, the phase transition (determined by the relationship between $E_{tot}$ and $T$), and combined with the Common Neighbors Analysis (CNA) method. The obtained results show that the first peak’s position ($r)$ of the RDF has negligible change value, $r=2.78$Å, which is completely consistent with the experimental results. For bulk Ag, there are always four types of structure: FCC, HCP, BCC, Amor and glass transition temperature $T_g=500$K. When decreasing the temperature, bulk Ag changes from liquid state to crystalline state, when increasing the annealing time at $T_g=500$K, bulk Ag changes from amorphous phase to crystalline phase state, leading to the increase of FCC, HCP, BCC structures and the decrease of Amor structure. The obtained results will be used as guide for future experiments.

Cellulose with at least one of its dimensions less than or equal to 100 nm is termed as nanocellulose. It is a unique and promising natural material extracted from native cellulose and produced by certain microbial cells and cell-free systems. Nanocellulose has received immense consideration in last couple of decades owing to its abundance, renewability, remarkable physical properties, special surface chemistry, and excellent biological features (biocompatibility, biodegradability, and non-toxicity). Taking advantage of the structure and properties of nanocellulose, the current science of biomaterials aims at developing new and formerly non-existing materials with novel and multifunctional properties, in an attempt to meet current requirements in different fields such as biomedicine, the environment, energy, pharmaceutics, agriculture, food, etc. This chapter provides an overview of different synthesis methods of nanocellulose: mechanical approaches by applying high-pressure, grinding, crushing, sonication, and milling; chemical synthesis involving alkaline, acidic, oxidation, and enzymatic treatment; as well as by using bacteria and cell-free systems. It further discusses different morphological forms of nanocellulose including cellulose nanocrystals (CNCs), cellulose nanofibers (CNFs), bacterial nanocellulose (BNC), and cellulose produced by cell-free systems, in terms of their features such as chemical structure, macrostructural morphology, physico-mechanical properties, thermal and biological properties, rheology, optical behavior, and their interrelationships and applications.