Cet article traite de la découverte de lithopone phosphorescent sur des dessins à l'aquarelle, datés entre 1890 et 1905, de l'artiste Américain John La Farge et de l'histoire du lithopone dans l'industrie des pigments à la fin du 19e et au début du 20e siècle. Malgré de nombreuses qualités souhaitables pour une utilisation en tant que blanc dans les aquarelles et les peintures à l'huile, le développement du lithopone comme pigment pour artistes a été compliqué de par sa tendance à noircir lorsqu'il est exposé au soleil. Sa disponibilité et son usage par les artistes demeurent incertains parce que les catalogues des marchands de couleurs n'étaient généralement pas explicites à indiquer si les pigments blancs contenaient du lithopone. De plus, lors d'un examen visuel, le lithopone peut être confondu avec le blanc de plomb et sa phosphorescence de courte durée peut facilement être ignorée par l'observateur non averti. À ce jour, le lithopone phosphorescent a seulement été documenté sur une autre œuvre: une aquarelle de Van Gogh. En plus de l'histoire de la fabrication du lithopone, cet article décrit le mécanisme de sa phosphorescence et son identification à l'aide de la spectroscopie Raman et de la spectrofluorimétrie. En este artículo se discute el descubrimiento del litopón fosforescente en dibujos a la acuarela por el artista americano John La Farge, fechados de 1890 a 1905, y la historia del litopón en la industria de los pigmentos a finales del Siglo XIX y principios del Siglo XX. A pesar de tener muchas cualidades deseables para su uso en pintura para acuarela o pinturas al óleo blancas, el desarrollo del litopón como pigmento para artistas fue obstaculizado por su tendencia a oscurecerse con la luz solar. Su disponibilidad para los artistas y su adopción por ellos sigue siendo poco clara, ya que por lo general los catálogos comerciales de los coloristas no eran explícitos al describir si los pigmentos blancos contenían litopón. Además, el litopón se puede confundir con blanco de plomo durante el examen visual, y su fosforescencia de corta duración puede ser fácilmente pasada por alto por el observador desinformado. A la fecha, el litopón fosforescente ha sido documentado solamente en otra obra mas: una acuarela por Van Gogh. Además de la historia de la fabricación del litopón, el artículo detalla el mecanismo para su fosforescencia, y su identificación con la ayuda de espectroscopía de Raman, y de espectrofluorimetría. Este artigo discute a descoberta de litopônio fosforescente em desenhos de aquarela do artista americano John La Farge datados de entre 1890 e 1905 e a história do litopônio na indústria de pigmento no final do século XIX e início do século XX. Apesar de ter muitas qualidades desejáveis para o uso em aquarela branca ou tintas a óleo, o desenvolvimento do litopônio como um pigmento de artistas foi prejudicado por sua tendência a se escurecer na luz solar. Sua disponibilidade para e uso por parte de artistas ainda não está clara, uma vez que os catálogos comerciais dos vendedores de tintas geralmente não eram explícitos na descrição de pigmentos brancos como algo que contém litopônio. Além disso, o litopônio pode ser confundido com o branco de chumbo durante o exame visual e sua fosforescência de curta duração pode ser facilmente perdida pelo observador desinformado. O litopônio fosforescente foi documentado em apenas um outro trabalho até hoje: uma aquarela de Van Gogh. Além da história da manufatura do litopônio, o artigo detalha o mecanismo para a sua fosforescência e sua identificação auxiliada pela espectroscopia de Raman e espectrofluorimetria.
TiO2 comes in many different forms. However, only a few of these forms are considered food-grade (acceptable to be added to food). Many studies that raised concern about the safety of TiO2, including the concern for genotoxicity, used forms of TiO2 that are not considered acceptable for use in food and have different properties than food-grade TiO2. Other studies did use food-grade TiO2, but took steps to break the material down into smaller particles than what would normally be found in food.
3. Photocatalysis The photocatalytic properties of anatase make it valuable for environmental applications such as air and water purification. Manufacturers are exploring its potential in self-cleaning surfaces and photocatalytic reactors, which can degrade pollutants under UV light.
On the other hand, the U.S. Food and Drug Administration (FDA) in their Final Administrative Order on Sunscreen Drug Products posted in September 2021 still accepts titanium dioxide up to 25% in the list of Generally Recognized As Safe and Effective (GRASE) in the main document, without further clarification on what kind or size of particles [9]. However, on page 24 (Sunscreen containing nanomaterials) FDA clearly “distinguish nanomaterials from other forms of these ingredients'' (zinc oxide and titanium dioxide) and ask for comments on “any particular nanomaterials that you believe should not be permitted for use in OTC sunscreen products”. To the best of our knowledge, this Agency did not ban the use of nanoparticulate titanium dioxide in any form, even though it is mentioned on page 34 that the anatase form is the more photoactive one, due to the lack of evidence with real sunscreens OTC (over the counter) in vivo. Moreover, other regulations in Latin America (MERCOSUR agreement, 2006) do not state clearly their position on the use of nanoparticulate TiO2NPs [10].
The versatility of self-stick foam strips does not end there. They can also be used in crafting and DIY projects. Crafters frequently use these strips to add dimension to their projects, create texture, or even as a bonding agent for various materials. From scrapbooking to model building, the adhesive properties and varying thicknesses of foam strips make them an invaluable resource for creative minds.
Booster pump mechanical seals are fundamental to the efficient and reliable operation of pumping systems. Understanding their design, functionality, different types, and the importance of maintenance can significantly enhance operational performance and prevent costly downtime. By investing in quality seals and adhering to rigorous maintenance protocols, industries can ensure that their booster pumps operate at peak efficiency, delivering reliable service for years to come.
Improving Indoor Comfort
3. Water Treatment Facilities These seals play a crucial role in maintaining the efficiency and cleanliness of equipment in water treatment systems.
An exterior door weather seal is a type of sealing material that is installed around the perimeter of exterior doors. Its primary function is to close gaps between the door and its frame, preventing air leaks, moisture infiltration, and dirt or pest entry. Weather seals can be made from various materials, including rubber, foam, vinyl, and silicone. Each material has its advantages and disadvantages, making it essential to choose one that fits your specific needs.
Types of Weather Stripping
5. Safe and Non-Toxic Silicone is a non-toxic material, making these strips safe for various applications, including those within the healthcare sector. They are often used in medical devices and other health-related products due to their biocompatibility and ease of cleaning.
Materials Used
In addition to cosmetic benefits, rubber edge trims are an excellent choice for safety considerations. Safety should always be a priority in design, especially in high-traffic areas or products used in close proximity to people. The soft, flexible nature of rubber reduces the risk of cuts or abrasions caused by sharp edges. In places like schools, hospitals, and playgrounds, where safety is paramount, using flexible rubber edge trim can prevent injuries, thereby creating a more secure environment for everyone. Furthermore, these trims can also reduce noise when closing doors or drawers, contributing to a quieter atmosphere.
Wide rubber weather stripping is typically made from a soft, flexible rubber material that is designed to seal gaps and cracks around doors and windows. This helps to prevent heat loss in the winter and keep cool air in during the summer, saving you money on your energy bills and making your home more comfortable.
1. Protection from Physical Damage One of the primary functions of door trim protectors is to shield the sensitive surfaces of car doors from dents and scratches caused by accidental bumps in parking lots, careless movements during entry or exit, or even minor collisions. The protectors act as a barrier, absorbing impact and protecting the underlying door trim.
Additionally, the thermal insulation properties of rubber foam strips can improve energy efficiency. They help seal gaps around windows, doors, and other areas, reducing drafts and minimizing heating and cooling loss. This can lead to significant savings on energy bills over time.
When it comes to home improvement, one often-overlooked component is the weather stripping on exterior doors. Properly installed weather stripping not only enhances the aesthetic appeal of your home but also plays a crucial role in energy efficiency and comfort.
1. Felt Weather Stripping This type is typically used in older vehicles and is often less effective than newer options. Felt can compress over time and may become less durable.
In today’s world, where DIY projects and home improvement are becoming increasingly popular, cheap foam tape has emerged as a staple tool for a wide range of applications. This versatile adhesive tape, known for its durability and flexibility, is perfect for both professionals and hobbyists alike. With a blend of affordability and practicality, foam tape offers an array of uses, making it an essential item in any toolkit or household.
The role of silicone foam seals in modern manufacturing and product design cannot be overstated. Their unique combination of temperature resistance, chemical stability, and flexibility makes them ideal for a wide range of applications across multiple industries. As technology advances and the demand for more efficient and durable sealing solutions grows, silicone foam seals will continue to be a critical component in ensuring the reliability and longevity of products. Whether in automotive engineering, electronics, HVAC systems, or construction, investing in quality silicone foam seals is essential for enhanced performance and reduced maintenance costs over the lifespan of products.
In the HVAC industry, these pumps help in circulating water within heating and cooling systems. Their efficiency in maintaining optimal pressure levels contributes to energy savings and improved operational performance.
- Construction In the construction industry, these seals are used to weatherproof windows, doors, and roofing elements. They improve energy efficiency in buildings and protect against external elements.
One of the standout characteristics of 1% thick foam tape is its ability to conform to irregular surfaces. Unlike traditional adhesives that may not bond well to uneven textures, foam tape can easily fill gaps and adhere to both smooth and rough materials. This quality makes it especially popular in scenarios like mounting, sealing, and insulating.
Installation and Maintenance
Application of 4-Inch Weather Stripping
2. Thickness and Density Select the appropriate foam thickness and density to meet the sealing requirements.
In addition to these types of weather stripping, there are also some specialized options available for specific applications. For example, door sweeps are used to seal the gap between the bottom of a door and the floor, while door shoes are used to seal the gap between the bottom of a door and the threshold. These specialized options can provide additional insulation and help to further reduce drafts and energy loss.
Benefits of Enhanced Soundproofing
The Concept of Zero Leak
- Construction and Renovation Ideal for installing windows, doors, and panels, the tape provides a strong seal that enhances energy efficiency by reducing drafts.
1. Reduced Leakage One of the primary benefits of dry running mechanical seals is their ability to minimize leakage. This is particularly important in industries where fluid loss can have significant environmental or safety implications.
4. Brush Door Sweeps Featuring bristles that conform to uneven surfaces, these are particularly effective for keeping out dust and small pests.
What is a Mechanical Oil Seal?
3. Noise Reduction Apart from temperature control, door seals also offer sound insulation. They can help minimize the amount of noise that enters or exits a room, contributing to a quieter and more peaceful environment. This is especially beneficial for homes located in noisy areas or for those who value tranquility.
