Hardening is a process of increasing the hardness of a material through heat treatment, typically by heating and then cooling the material rapidly. Surface hardening, on the other hand, is a specific type of hardening process that only affects the surface layer of the material, leaving the core unchanged. Surface hardening techniques include carburizing, nitriding, and induction hardening, which are used to improve wear resistance and durability of the material's surface. Overall, the main difference between hardening and surface hardening lies in the depth of the hardened layer and the extent of the material affected. **

Some hidden gems in London include the Leighton House Museum, a beautifully preserved Victorian home with stunning Middle Eastern-inspired interiors, and the Hampstead Heath Pergola and Hill Garden, a tranquil and picturesque spot with stunning views of the city. Another hidden gem is the Little Venice area, a peaceful canal network with charming houseboats and waterside cafes. Additionally, the Sir John Soane's Museum, a unique house museum filled with an eclectic collection of art and antiquities, is a must-visit for history and architecture enthusiasts. **

Hidden gems like Kemono Jihen are lesser-known anime series that offer a unique and captivating story, compelling characters, and stunning animation. These hidden gems often fly under the radar but have a dedicated fanbase due to their high-quality storytelling and production. Kemono Jihen, in particular, stands out for its blend of supernatural elements, mystery, and character development, making it a must-watch for fans of the genre. These hidden gems often provide a refreshing and memorable viewing experience for anime enthusiasts looking for something new and different. **

Some short anime hidden gems include "Barakamon," a heartwarming slice-of-life series about a calligrapher finding inspiration in a rural village; "Tatami Galaxy," a unique and visually stunning show about a college student's surreal experiences; and "Anohana: The Flower We Saw That Day," a touching story about a group of friends dealing with grief and guilt. These anime may not be as well-known as some others, but they offer compelling stories and memorable characters that make them worth watching. **

Case hardening involves increasing the hardness of the surface of a metal while maintaining a softer core, typically by introducing carbon or nitrogen into the surface layer. This process creates a hard outer layer that is resistant to wear and tear, while the core remains tough and durable. Surface hardening, on the other hand, involves increasing the hardness of the entire surface of a metal, typically through processes such as heat treatment or coating. This results in a uniformly hardened surface that is resistant to abrasion and other forms of surface damage. **

Some hidden gems for the PC include OBS Studio, a free and open-source software for video recording and live streaming; DaVinci Resolve, a powerful video editing software with advanced features; and HandBrake, a tool for converting video files to different formats. These software are not as well-known as some of the more popular options, but they offer high-quality features and functionality for users looking for alternatives. **

Yes, it is normal for certain materials to harden over time due to factors such as exposure to air, moisture, or temperature changes. For example, concrete hardens as it cures, and metals can harden through processes like cold working or heat treatment. However, if a material is hardening unexpectedly or excessively, it could be a sign of a problem such as improper storage or handling, or a chemical reaction taking place. It's important to understand the specific material and its properties to determine if the hardening process is normal or if there is an issue that needs to be addressed. **

One hidden gem that I would recommend is "Hollow Knight," a beautifully crafted indie game with challenging gameplay and a captivating world to explore. Another hidden gem is "Celeste," a platformer with a touching story and tight controls that make for a rewarding experience. Lastly, "Undertale" is a unique RPG that subverts traditional game mechanics and offers players a thought-provoking narrative. **