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Surface states refer to electronic states that exist at the surface of a material, particularly in solid-state physics and materials science. Unlike bulk states, which are found in the interior of a material, surface states arise due to the termination of the periodic potential created by the lattice of atoms in a solid. When the material's surface is exposed to the environment, the atoms at the surface are less coordinated compared to those in the bulk, leading to a distinct electronic structure.

The swelling index is a measurement used primarily in the context of materials, particularly clays and soils, to quantify the degree to which a material expands when it interacts with water or other solvents. It is an important parameter in various fields, including geotechnical engineering, agriculture, and environmental science. In the context of soils, the swelling index indicates how much a soil will swell when it becomes saturated with water. This is especially relevant for clay soils, which can significantly change volume with moisture content fluctuations.

Syntactic foam is a composite material that consists of a polymer matrix filled with hollow microspheres or microballoons. These microspheres are often made from materials like glass or ceramics, and they provide the foam with unique properties. The combination of the polymer matrix and the embedded microspheres results in a lightweight, buoyant, and strong material.

Temperature-Programmed Reduction (TPR) is a technique used in materials science and catalysis to study the reduction properties of metal oxides, catalysts, and other materials. The process involves heating a sample in a controlled manner while exposing it to a reducing agent, typically hydrogen (H₂) or other gases like carbon monoxide (CO).

In mineralogy, "tenacity" refers to the resistance of a mineral to deformation, breaking, or being separated. It describes how a mineral reacts to stress or pressure, particularly in terms of its physical properties. Tenacity can be classified into several categories based on how a mineral responds to different types of stress: 1. **Malleable**: Can be hammered into thin sheets or shaped without breaking (e.g., gold).

Terahertz nondestructive evaluation (THz NDE) is a technique that utilizes terahertz (THz) radiation, which falls in the frequency range between microwave and infrared radiation (approximately 0.1 to 10 THz), to inspect and analyze materials and structures without causing any damage. This method exploits the unique interaction of THz waves with different materials, enabling the detection of flaws, moisture content, and other properties.

Testing of advanced thermoplastic composite welds involves evaluating the integrity and performance of welded joints made from thermoplastic composite materials. These materials, which combine the properties of thermoplastics with reinforcing fibers, offer high strength-to-weight ratios, flexibility, and resistance to environmental degradation. However, they present unique challenges in welding and joining processes compared to traditional thermosetting composites or metals.

In chemistry, the term "texture" can refer to various aspects depending on the context, including the physical characteristics of a substance, the arrangement of its components, or the way it interacts with other materials. Here are some common interpretations: 1. **Solid Samples:** In solid materials, texture relates to the size, shape, and arrangement of the particles or crystals within the solid. This can affect properties such as hardness, strength, and reactivity.

Theoretical strength of a solid refers to the strength that a material can potentially exhibit based on its atomic or molecular structure, assuming ideal or perfect conditions without defects, imperfections, or dislocations. This measurement is often derived from fundamental principles of solid mechanics and materials science, particularly considering the bond strengths between atoms or molecules.

Thermal analysis is a set of techniques used to study the physical and chemical properties of materials as they change with temperature. These techniques measure how a material reacts to changes in temperature, providing insights into its behavior, stability, composition, and phase transitions. Common types of thermal analysis include: 1. **Differential Scanning Calorimetry (DSC)**: Measures the heat flow associated with phase transitions in materials as a function of temperature.

Thermal Barrier Coating (TBC) is a specialized coating applied to components, particularly those exposed to high temperatures and harsh environments, to insulate them from heat and protect them from thermal and oxidation-related damage. TBCs are commonly used in applications such as gas turbines, jet engines, and industrial heat engines, where they enable materials to withstand higher operating temperatures, improve efficiency, and extend the lifespan of components.

Thermal history coating, also known as thermal history indicator or thermal monitoring coating, refers to a type of thermochromic coating that changes color in response to temperature variations over time. This technology is often used to indicate heat exposure for materials, components, or products in various industries, including aerospace, automotive, and electronics.

Thermal Interface Material (TIM) refers to materials used to enhance the thermal conductivity between two surfaces, typically between a heat-generating component (like a CPU, GPU, or power transistor) and a heat sink or other heat dissipation element. The primary purpose of TIM is to fill microscopic air gaps and irregularities between surfaces to improve thermal transfer efficiency.

Thermal spraying is a versatile surface engineering technique used to apply a coating to a substrate to enhance its properties such as wear resistance, corrosion resistance, and thermal protection. The process involves generating a spray of molten or semi-molten materials (called feedstock) that are propelled onto the surface of a substrate. Once these particles impact the substrate, they cool and solidify, forming a coating that adheres to the surface.

Thermally Stimulated Depolarization Current (TSDC) is a technique used to study the electrical properties of insulating materials, particularly in the context of dielectric materials and polymers. This method is primarily employed to investigate charge transport mechanisms, polarization phenomena, and the behavior of electrical dipoles in materials.

Thermoelectric materials are substances that can convert temperature differences directly into electrical voltage and vice versa. They harness the thermoelectric effect, which involves the interplay between thermal and electrical conductivity. This capability makes them useful for a variety of applications, including: 1. **Power Generation**: By utilizing waste heat from industrial processes, engines, or even from the sun, thermoelectric materials can generate electricity.

Thermomechanical analysis (TMA) is a technique used to study the mechanical properties of materials as they change with temperature. It involves applying a controlled temperature program to a sample while simultaneously measuring its mechanical response, such as dimensional changes, stiffness, or viscoelastic properties. This analysis helps in understanding how materials behave under thermal conditions, which is particularly important for polymers, metals, ceramics, and composites.

Thermoplastic olefin (TPO) is a type of polymer blend made primarily from a combination of polypropylene (PP) and ethylene-propylene rubber (EPR or EPDM). TPO is characterized by its rubber-like properties, which provide flexibility, impact resistance, and durability, while also possessing the processability of thermoplastics.

A thin film is a layer of material ranging from fractions of a nanometer to several micrometers in thickness. Thin films can be composed of various materials, including metals, semiconductors, insulators, and polymers. They are often deposited onto substrates (like glass, silicon, or metals) using various techniques, such as physical vapor deposition (PVD), chemical vapor deposition (CVD), sputtering, and spin coating.

Thiomer is a term that is often associated with a specific class of pharmaceutical compounds known as thiomers or thiolated polymers. These compounds are typically modified polymers that have thiol (-SH) groups incorporated into their structure. Thiomers are researched for various applications, particularly in drug delivery systems, due to their unique properties such as enhanced stability, biocompatibility, and the ability to form strong interactions with biological components.